Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2016	Feb. 22, 2017	Jun. 30, 2016
Document and Entity Information [Abstract]
Entity Registrant Name	KIRBY CORP
Entity Central Index Key	0000056047
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Public Float			$ 3,278,025,000
Entity Common Stock, Shares Outstanding		53,957,000
Document Fiscal Year Focus	2016
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2016

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 5,634	$ 5,885
Accounts receivable:
Trade - less allowance for doubtful accounts of $7,240 ($9,374 in 2015)	297,177	290,931
Other	95,327	102,443
Inventories - at lower of average cost or market	185,402	184,511
Prepaid expenses and other current assets	49,411	45,283
Deferred income taxes	13,604	11,723
Total current assets	646,555	640,776
Property and equipment:
Marine transportation equipment	4,071,972	3,806,850
Land, buildings and equipment	256,925	252,913
Property and equipment	4,328,897	4,059,763
Accumulated depreciation	1,407,523	1,280,783
Property and equipment - net	2,921,374	2,778,980
Investment in affiliates	2,622	2,090
Goodwill	598,131	586,718
Other assets	134,817	143,717
Total assets	4,303,499	4,152,281
Current liabilities:
Current portion of long-term debt	0	0
Income taxes payable	3,288	3,564
Accounts payable	134,571	132,799
Accrued liabilities:
Interest	5,397	5,412
Insurance premiums and claims	123,371	111,705
Employee compensation	26,916	37,243
Taxes - other than on income	15,481	13,525
Other	13,313	16,369
Deferred revenues	36,001	41,300
Total current liabilities	358,338	361,917
Long-term debt - less current portion	722,802	774,849
Deferred income taxes	719,057	669,808
Other long-term liabilities	90,435	66,511
Total long-term liabilities	1,532,294	1,511,168
Contingencies and commitments
Kirby stockholders' equity:
Common stock, $.10 par value per share. Authorized 120,000,000 shares, issued 59,776,000 in 2016 and 2015	5,978	5,978
Additional paid-in capital	432,459	434,783
Accumulated other comprehensive income - net	(51,007)	(44,686)
Retained earnings	2,342,236	2,200,830
Treasury stock - at cost, 5,921,000 shares in 2016 and 6,056,000 in 2015	(320,348)	(328,094)
Total Kirby stockholders' equity	2,409,318	2,268,811
Noncontrolling interests	3,549	10,385
Total equity	2,412,867	2,279,196
Total liabilities and equity	$ 4,303,499	$ 4,152,281

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Current assets:
Trade, allowance for doubtful accounts	$ 7,240	$ 9,374
Kirby stockholders' equity:
Common stock, par value per share (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	120,000,000	120,000,000
Common stock, shares issued (in shares)	59,776,000	59,776,000
Treasury stock, shares (in shares)	5,921,000	6,056,000

CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenues:
Marine transportation	$ 1,471,893	$ 1,663,090	$ 1,770,684
Diesel engine services	298,780	484,442	795,634
Total revenues	1,770,673	2,147,532	2,566,318
Costs and expenses:
Costs of sales and operating expenses	1,126,952	1,362,366	1,694,882
Selling, general and administrative	174,752	193,237	210,416
Taxes, other than on income	22,730	20,699	16,677
Depreciation and amortization	200,917	192,240	169,312
Loss (gain) on disposition of assets	127	(1,672)	(781)
Total costs and expenses	1,525,478	1,766,870	2,090,506
Operating income	245,195	380,662	475,812
Equity in earnings of affiliates	532	451	384
Other expense	(291)	(663)	(345)
Interest expense	(17,690)	(18,738)	(21,461)
Earnings before taxes on income	227,746	361,712	454,390
Provision for taxes on income	(84,942)	(133,742)	(169,782)
Net earnings	142,804	227,970	284,608
Less: Net earnings attributable to noncontrolling interests	(1,398)	(1,286)	(2,602)
Net earnings attributable to Kirby	$ 141,406	$ 226,684	$ 282,006
Net earnings per share attributable to Kirby common stockholders:
Basic (in dollars per share)	$ 2.63	$ 4.12	$ 4.95
Diluted (in dollars per share)	$ 2.62	$ 4.11	$ 4.93

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings	$ 142,804	$ 227,970	$ 284,608
Other comprehensive income (loss), net of taxes:
Pension and postretirement benefits	(6,321)	16,322	(44,294)
Foreign currency translation adjustments	0	29	(35)
Change in fair value of derivative instruments	0	0	85
Total other comprehensive income (loss), net of taxes	(6,321)	16,351	(44,244)
Total comprehensive income, net of taxes	136,483	244,321	240,364
Net earnings attributable to noncontrolling interests	(1,398)	(1,286)	(2,602)
Comprehensive income attributable to Kirby	$ 135,085	$ 243,035	$ 237,762

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash flows from operating activities:
Net earnings	$ 142,804	$ 227,970	$ 284,608
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	200,917	192,240	169,312
Provision (credit) for doubtful accounts	(467)	1,426	3,577
Provision for deferred income taxes	51,296	62,755	77,976
Loss (gain) on disposition of assets	127	(1,672)	(781)
Equity in earnings of affiliates, net of distributions and contributions	(532)	449	(384)
Amortization of unearned share-based compensation	11,675	11,104	11,591
Amortization of major maintenance costs	19,869	22,126	16,409
Amortization of debt issuance costs	801	1,377	2,362
Increase (decrease) in cash flows resulting from changes in:
Accounts receivable	(12,750)	129,908	(176,544)
Inventory	3,182	(7,320)	(56,468)
Other assets	(30,853)	(15,551)	(14,145)
Income taxes payable	15,413	477	(4,544)
Accounts payable	(1,739)	(81,808)	44,645
Accrued and other liabilities	14,295	(22,176)	81,295
Net cash provided by operating activities	414,038	521,305	438,909
Cash flows from investing activities:
Capital expenditures	(231,066)	(345,475)	(355,144)
Acquisitions of businesses and marine equipment	(137,072)	(41,250)	(31,800)
Proceeds from disposition of assets	18,617	24,429	10,393
Net cash used in investing activities	(349,521)	(362,296)	(376,551)
Cash flows from financing activities:
Borrowings (payments) on bank credit facilities, net	(52,848)	160,784	75,550
Payments on long-term debt	0	(100,000)	(108,000)
Return of investment to noncontrolling interests	(1,976)	(1,778)	(3,192)
Proceeds from exercise of stock options	321	3,712	7,519
Purchase of treasury stock	(1,827)	(241,105)	(15,321)
Payment of contingent liability	0	0	(4,756)
Acquisition of noncontrolling interest	(8,438)	0	0
Excess tax benefit from equity compensation plans	0	964	6,119
Net cash used in financing activities	(64,768)	(177,423)	(42,081)
Increase (decrease) in cash and cash equivalents	(251)	(18,414)	20,277
Cash and cash equivalents, beginning of year	5,885	24,299	4,022
Cash and cash equivalents, end of year	5,634	5,885	24,299
Supplemental disclosures of cash flow information:
Interest paid	19,878	20,586	19,622
Income taxes paid	18,162	69,584	90,460
Capital expenditures included in accounts payable	(2,037)	2,206	0
Fair value of property transferred in acquisition	$ 3,681	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Total
Balance at beginning of year at Dec. 31, 2013	$ 5,978	$ 410,615	$ (16,793)	$ 1,692,140	$ (81,254)	$ 11,467
Excess (deficit) of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		8,345
Tax benefit (expense) realized from equity compensation plans		6,119					$ 6,119
Issuance of restricted stock, net of forfeitures		(8,195)
Amortization of unearned compensation		11,591
Acquisitions of noncontrolling interests		0				0
Net earnings attributable to Kirby for the year				282,006			282,006
Purchase of treasury stock (35,000 in 2016 and 3,316,000 in 2015)					(15,321)
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (170,000 in 2016, 166,000 in 2015 and 211,000 in 2014)					3,049
Net earnings attributable to noncontrolling interests						2,602	2,602
Return of investment to noncontrolling interests						(3,192)	3,192
Other comprehensive income (loss), net of taxes			(44,244)				(44,244)
Balance at end of year at Dec. 31, 2014	5,978	428,475	(61,037)	1,974,146	(93,526)	10,877
Excess (deficit) of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		3,530
Tax benefit (expense) realized from equity compensation plans		964					964
Issuance of restricted stock, net of forfeitures		(9,290)
Amortization of unearned compensation		11,104
Acquisitions of noncontrolling interests		0				0
Net earnings attributable to Kirby for the year				226,684			226,684
Purchase of treasury stock (35,000 in 2016 and 3,316,000 in 2015)					(241,105)
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (170,000 in 2016, 166,000 in 2015 and 211,000 in 2014)					6,537
Net earnings attributable to noncontrolling interests						1,286	1,286
Return of investment to noncontrolling interests						(1,778)	1,778
Other comprehensive income (loss), net of taxes			16,351				16,351
Balance at end of year at Dec. 31, 2015	5,978	434,783	(44,686)	2,200,830	(328,094)	10,385	2,279,196
Excess (deficit) of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		(755)
Tax benefit (expense) realized from equity compensation plans		(824)					(824)
Issuance of restricted stock, net of forfeitures		(10,218)
Amortization of unearned compensation		11,675
Acquisitions of noncontrolling interests		(2,202)				(6,258)
Net earnings attributable to Kirby for the year				141,406			141,406
Purchase of treasury stock (35,000 in 2016 and 3,316,000 in 2015)					(1,827)
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (170,000 in 2016, 166,000 in 2015 and 211,000 in 2014)					9,573
Net earnings attributable to noncontrolling interests						1,398	1,398
Return of investment to noncontrolling interests						(1,976)	1,976
Other comprehensive income (loss), net of taxes			(6,321)				(6,321)
Balance at end of year at Dec. 31, 2016	$ 5,978	$ 432,459	$ (51,007)	$ 2,342,236	$ (320,348)	$ 3,549	$ 2,412,867

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - Treasury Stock [Member] - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Purchase of treasury stock (in shares)	35,000	3,316,000
Treasury stock issued upon exercise of stock options and issuance of restricted stock (in shares)	170,000	166,000	211,000

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	(1) Summary of Significant Accounting Policies Principles of Consolidation. The consolidated financial statements include the accounts of Kirby Corporation and all majority-owned subsidiaries (“the Company”). All investments in which the Company owns 20% to 50% and exercises significant influence over operating and financial policies are accounted for using the equity method. All material intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to reflect the current presentation of financial information. Accounting Policies Cash Equivalents. Cash equivalents consist of all short-term, highly liquid investments with maturities of three months or less at date of purchase. Accounts Receivable. In the normal course of business, the Company extends credit to its customers. The Company regularly reviews the accounts and makes adequate provisions for probable uncollectible balances. It is the Company’s opinion that the accounts have no impairment, other than that for which provisions have been made. Included in accounts receivable as of December 31, 2016 and 2015 were $84,453,000 and $90,166,000, respectively, of accruals for revenues earned which have not been invoiced as of the end of each year. The Company’s marine transportation and diesel engine services operations are subject to hazards associated with such businesses. The Company maintains insurance coverage against these hazards with insurance companies. Included in accounts receivable as of December 31, 2016 and 2015 were $88,182,000 and $77,684,000, respectively, of receivables from insurance companies to cover claims in excess of the Company’s deductible. Concentrations of Credit Risk. Financial instruments which potentially subject the Company to concentrations of credit risk are primarily trade accounts receivables. The Company’s marine transportation customers include the major oil refining and petrochemical companies. The diesel engine services customers are oil and gas service companies, marine transportation companies, commercial fishing companies, power generation companies, and the United States government. The Company regularly reviews its accounts and estimates the amount of uncollectible receivables each period and establishes an allowance for uncollectible amounts. The amount of the allowance is based on the age of unpaid amounts, information about the current financial strength of customers, and other relevant information. Estimates of uncollectible amounts are revised each period, and changes are recorded in the period they become known. Fair Value of Financial Instruments. Cash, accounts receivable, accounts payable and accrued liabilities have carrying values that approximate fair value due to the short-term maturity of these financial instruments. The fair value of the Company’s debt instruments is more fully described in Note 5, Long-Term Debt. Property, Maintenance and Repairs. Property is recorded at cost. Improvements and betterments are capitalized as incurred. Depreciation is recorded on the straight-line method over the estimated useful lives of the individual assets as follows: marine transportation equipment, 5-40 years; buildings, 10-40 years; other equipment, 2-10 years; and leasehold improvements, term of lease. When property items are retired, sold or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts with any gain or loss on the disposition included in the statement of earnings. Maintenance and repairs on vessels built for use on the inland waterways are charged to operating expense as incurred and includes the costs incurred in United States Coast Guard (“USCG”) inspections unless the shipyard extends the life or improves the operating capacity of the vessel which results in the costs being capitalized. Drydocking on Ocean-Going Vessels. The Company’s ocean-going vessels are subject to regulatory drydocking requirements after certain periods of time to be inspected, have planned major maintenance performed and be recertified by the American Bureau of Shipping (“ABS”). These recertifications generally occur twice in a five year period. The Company defers the drydocking expenditures incurred on its ocean-going vessels due to regulatory marine inspections by the ABS and amortizes the costs of the shipyard over the period between drydockings, generally 30 or 60 months, depending on the type of major maintenance performed. Drydocking expenditures that extend the life or improve the operating capability of the vessel result in the costs being capitalized. The Company recognized amortization of major maintenance costs of $19,869,000, $22,126,000 and $16,409,000 for the years ended December 31, 2016, 2015 and 2014, respectively, in costs of sales and operating expenses. Routine repairs and maintenance on ocean-going vessels are expensed as incurred. Interest is capitalized on the construction of new ocean-going vessels. Interest expense excludes capitalized interest of $2,974,000, $3,026,000 and $639,000 for the years ending December 31, 2016, 2015 and 2014, respectively. Environmental Liabilities. The Company expenses costs related to environmental events as they are incurred or when a loss is considered probable and estimable. Goodwill. The excess of the purchase price over the fair value of identifiable net assets acquired in transactions accounted for as a purchase is included in goodwill. The Company conducted its annual goodwill impairment test at November 30, 2016 and 2015. For 2016 and 2015, the Company noted no impairment of goodwill. The Company will continue to conduct goodwill impairment tests as of November 30 of subsequent years, or whenever events or circumstances indicate that interim impairment testing is necessary. The amount of goodwill impairment, if any, is typically measured based on projected discounted future operating cash flows using an appropriate discount rate. The gross carrying value of goodwill at December 31, 2016 and 2015 was $615,598,000 and $604,185,000, respectively, and accumulated amortization at December 31, 2016 and 2015 was $15,566,000. Accumulated impairment losses were $1,901,000 at December 31, 2016 and 2015. Net goodwill for the marine transportation segment was $382,227,000 and $381,243,000 at December 31, 2016 and 2015, respectively. The increase in net goodwill for the marine transportation segment was due to the purchase of an inland tank barge fleet in 2016 which is more fully described in Note 2, Acquisitions. Net goodwill for the diesel engine services segment was $215,904,000 and $205,475,000 at December 31, 2016 and 2015, respectively. The increase in net goodwill for the diesel engine services segment was mainly due to the acquisition of an engine supply and repair business in 2016, also more fully described in Note 2, Acquisitions. Revenue Recognition. The majority of marine transportation revenue is derived from term contracts, ranging from one to five years, some of which have renewal options, and the remainder is from spot market movements. The majority of the term contracts are for terms of one year. The Company is a provider of marine transportation services for its customers and, in almost all cases, does not assume ownership of the products it transports. A term contract is an agreement with a specific customer to transport cargo from a designated origin to a designated destination at a set rate or at a daily rate. The rate may or may not escalate during the term of the contract, however, the base rate generally remains constant and contracts often include escalation provisions to recover changes in specific costs such as fuel. A spot contract is an agreement with a customer to move cargo from a specific origin to a designated destination for a rate negotiated at the time the cargo movement takes place. Spot contract rates are at the current “market” rate, including fuel, and are subject to market volatility. The Company uses a voyage accounting method of revenue recognition for its marine transportation revenues which allocates voyage revenue based on the percent of the voyage completed during the period. There is no difference in the recognition of revenue between a term contract and a spot contract. Diesel engine service products and services are generally sold based upon purchase orders or preferential service agreements with the customer that include fixed or determinable prices and that do not include right of return or significant post-delivery performance obligations. Diesel engine parts sales are recognized when title passes upon shipment to customers or when customer-specific acceptance requirements are met. Service revenue is recognized as the service is provided. Diesel manufacturing and assembly projects revenue is reported on the percentage of completion method of accounting using measurements of progress towards completion appropriate for the work performed. Stock-Based Compensation. The Company has share-based compensation plans covering selected officers and other key employees as well as the Company’s Board of Directors. Stock-based grants made under the Company’s stock plans are recorded at fair value on the date of the grant and the cost is recognized ratably over the vesting period of the stock option or restricted stock. Stock option grants are valued at the date of grant as calculated under the Black-Scholes option pricing model. The Company’s stock-based compensation plans are more fully described in Note 8, Stock Award Plans. Taxes on Income. The Company follows the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Accrued Insurance. Accrued insurance liabilities include estimates based on individual incurred claims outstanding and an estimated amount for losses incurred but not reported (“IBNR”) or fully developed based on past experience. Insurance premiums, IBNR losses and incurred claim losses, in excess of the Company’s deductible for 2016, 2015 and 2014 were $23,085,000, $23,737,000 and $25,416,000, respectively. Noncontrolling Interests. The Company has a majority interest in and is the general partner in several affiliated entities. In situations where losses applicable to the minority interest in the affiliated entities exceed the limited partners’ equity capital, such excess and any further loss attributable to the minority interest is charged against the Company’s interest in the affiliated entities. If future earnings materialize in the respective affiliated entities, the Company’s interest would be credited to the extent of any losses previously absorbed. Treasury Stock. The Company follows the average cost method of accounting for treasury stock transactions. Impairment of Long-Lived Assets and for Long-Lived Assets to Be Disposed Of. The Company reviews long-lived assets and certain identifiable intangibles for impairment by vessel class whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability on marine transportation assets is assessed based on vessel classes, not on individual assets, because identifiable cash flows for individual marine transportation assets are not available. Projecting customer contract volumes allows estimation of future cash flows by projecting pricing and utilization by vessel class but it is not practical to project which individual marine transportation asset will be utilized for any given contract. Because customers do not specify which particular vessel is used, prices are quoted based on vessel classes not individual assets. Nominations of vessels for specific jobs are determined on a day by day basis and are a function of the equipment class required and the geographic position of vessels within that class at that particular time as vessels within a class are interchangeable and provide the same service. The Company’s vessels are mobile assets and equipped to operate in geographic regions throughout the United States and the Company has in the past and expects to continue to move vessels from one region to another when it is necessary due to changing markets and it is economical to do so. Barge vessel classes are based on similar capacities, hull type, and type of product and towing vessels are based on similar hull type and horsepower. Recoverability of the vessel classes is measured by a comparison of the carrying amount of the assets to future net cash flows expected to be generated by the assets. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell. Accounting Standards In August 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments” (“ASU 2016-15”) to create consistency in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 is effective for annual and interim periods beginning after December 15, 2017. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”) which simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, forfeitures, minimum statutory tax withholding requirements, classification as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for annual and interim periods beginning after December 15, 2016. The Company will adopt the provisions of ASU 2016-09 on January 1, 2017 and the Company does not expect the adoption of ASU 2016-09 to have a material impact on its consolidated financial statements. However, the adoption will result in some income statement volatility in 2017 and beyond due to the requirement that the tax effects of exercised or vested equity awards be recognized as discrete items in income tax expense or benefit in the income statement in the reporting period in which they occur. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”) to increase transparency and comparability among organizations by requiring recognition of lease assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018, with early adoption permitted. A modified retrospective approach is required. The Company has formed a project team to evaluate the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. The project team has completed training on the new standard and has started lease review and documentation, but the Company has not yet determined the effect of ASU 2016-02 on its ongoing financial reporting. In November 2015, the FASB issued ASU 2015-17, “Balance Sheet Classification of Deferred Taxes” (“ASU 2015-17”) which requires that deferred tax liabilities and assets be classified as noncurrent on the balance sheet. The current requirement that deferred tax liabilities and assets of a tax-paying component of an entity be offset and presented as a single amount is not affected by this guidance. ASU 2015-17 is effective for annual and interim periods beginning after December 15, 2016 but early application is permitted and the guidance may be applied either prospectively to all deferred tax liabilities and assets or retrospectively to all periods presented. The Company will adopt the provisions of ASU 2015-17 on January 1, 2017 and the Company does not expect the adoption of ASU 2015-17 to have a material impact on its consolidated financial statements. In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory” (“ASU 2015-11”) which applies to inventory that is measured using first-in, first-out (“FIFO”) or average cost. Under the guidance, an entity should measure inventory that is within the scope of this update at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. ASU 2015-11 is effective for annual and interim periods beginning after December 15, 2016, and should be applied prospectively with early adoption permitted at the beginning of an interim period or annual reporting period. The Company will adopt the provisions of ASU 2015-11 on January 1, 2017 and the Company does not expect the adoption of ASU 2015-11 to have a material impact on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”). ASU 2015-03 requires debt issuance costs to be presented in the balance sheet as a direct deduction from the associated debt liability. Effective January 1, 2016, the Company adopted the provisions of ASU 2015-03 and prior period amounts have been reclassified to conform to the current period presentation. The December 31, 2015 net debt issuance costs of $3,985,000 have been reclassified in the consolidated balance sheet from other assets to long-term debt, less current portion. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern” (“ASU 2014-15”), which provides guidance about management's responsibility in evaluating whether there is substantial doubt relating to an entity’s ability to continue as a going concern and to provide related footnote disclosures as applicable. Adoption of ASU 2014-15 as of December 31, 2016 did not impact the Company’s financial statements or disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 will replace most existing revenue recognition guidance in United States Generally Accepted Accounting Principles when it becomes effective. In July 2015, the FASB voted to delay the effective date of ASU 2014-09 by one year, making it effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted as of the original effective date. ASU 2014-09 permits the use of either the retrospective, modified retrospective or prospective with a cumulative catch-up approach. The Company has formed a project team to evaluate the standard and determine the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. The project team has completed training on the new standard and has started contract review and documentation. The Company has not yet selected a transition method nor has it determined the effect of ASU 2014-09 on its ongoing financial reporting.

Acquisitions	12 Months Ended
Acquisitions	Dec. 31, 2016
Acquisitions [Abstract]
Acquisitions	(2) ACQUISITIONS On October 11, 2016, the Company purchased certain assets of Valley Power Systems, Inc. and Valley Power Systems Northwest, Inc. (collectively “VPS”) for $11,440,000 in cash. The assets purchased are mainly related to the EMD Power Products (“EMD”) engine supply and repair business of VPS and include an EMD distributor agreement to sell engines in nine western states. As a result of the acquisition, the Company recorded $8,330,000 of goodwill and $2,070,000 of intangibles with a weighted average amortization period of approximately 15 years. The Company expects all of the goodwill to be deductible for tax purposes. On June 30, 2016, the Company purchased an 80,000 barrel coastal tank barge from TD Equipment Finance, Inc. (“TD Equipment”) for $13,682,000 in cash. The Company had been leasing the barge from TD Equipment prior to its purchase. On June 2, 2016, the Company purchased four coastal tugboats from Crosby Marine Transportation LLC for $26,450,000 in cash. The four coastal tugboats have an average age of 13 years. On April 15, 2016, the Company purchased the inland tank barge fleet of SEACOR Holdings Inc. (“Seacor”) from subsidiaries of Seacor for a total value of $89,181,000. The assets purchased consisted of 27 inland 30,000 barrel tank barges and 14 inland towboats. The purchase price was comprised of $85,500,000 in cash and the transfer to Seacor of a Florida-based ship docking tugboat with a value of $3,681,000. The average age of the 27 inland tank barges was ten years. Seacor, through its subsidiary, SCF Waxler Marine LLC, transported refined petroleum products, petrochemicals and black oil on the Mississippi River System and the Gulf Intracoastal Waterway. As a result of the acquisition, the Company recorded $985,000 of goodwill and expects all of the goodwill to be deductible for tax purposes. No intangibles other than goodwill were identified in the acquisition. Pro forma results of the acquisitions made in 2016 have not been presented as the pro forma revenues, earnings before taxes on income, net earnings and net earnings per share would not be materially different from the Company’s actual results.

- Definition

The entire disclosure for a business combination (or series of individually immaterial business combinations) completed during the period, including background, timing, and recognized assets and liabilities. The disclosure may include leverage buyout transactions (as applicable).

+ References

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-Name Accounting Standards Codification
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+ Details

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2016
Fair Value Measurements [Abstract]
Fair Value Measurements	(4) Fair Value Measurements The accounting guidance for using fair value to measure certain assets and liabilities establishes a three tier value hierarchy, which prioritizes the inputs to valuation techniques used in measuring fair value. These tiers include: Level 1, defined as observable inputs such as quoted prices in active markets for identical assets or liabilities; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs in which little, if any, market data exists, therefore requiring an entity to develop its own assumptions about the assumptions that market participants would use in pricing the asset or liability. Cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities have carrying values that approximate fair value due to the short-term maturity of these financial instruments. The fair value of the Company’s debt instruments is described in Note 5, Long-Term Debt. Certain assets are measured at fair value on a nonrecurring basis. These assets are adjusted to fair value when there is evidence of impairment. During the years ended December 31, 2016 and 2015, there was no indication that the Company’s long-lived assets were impaired, and accordingly, measurement at fair value was not required.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Long-Term Debt

12 Months Ended

Dec. 31, 2016

Long-Term Debt [Abstract]

Long-Term Debt

(5) Long-Term Debt

Long-term debt at December 31, 2016 and 2015 consisted of the following (in thousands):

	2016			2015
Long-term debt, including current portion:
$550,000,000 revolving credit facility due April 30, 2020	$	225,986		$	278,834
$150,000,000 senior notes Series A due February 27, 2020		150,000			150,000
$350,000,000 senior notes Series B due February 27, 2023		350,000			350,000
$10,000,000 credit line due June 30, 2017		—			—
	$	725,986		$	778,834
Unamortized debt issuance costs		(3,184	)		(3,985	)
	$	722,802		$	774,849

The aggregate payments due on the long-term debt in each of the next five years were as follows (in thousands):

2017	$	—
2018		—
2019		—
2020		375,986
2021		—
Thereafter		350,000
	$	725,986

The Company has a $550,000,000 unsecured revolving credit facility (“Revolving Credit Facility”) with a syndicate of banks, with JPMorgan Chase Bank, N.A. as the administrative agent bank, with a maturity date of April 30, 2020. In addition, the credit agreement allows for a $300,000,000 increase in the aggregate commitments of the banks in the form of revolving credit loans or term loans, subject to the consent of each bank that elects to participate in the increased commitment. The variable interest rate spread varies with the Company’s senior debt rating and is currently 1.00% over the London Interbank Offered Rate (“LIBOR”) or equal to an alternate base rate calculated with reference to the agent bank’s prime rate, among other factors (“Alternate Base Rate”). The commitment fee is currently 0.10%. The Revolving Credit Facility contains certain restrictive financial covenants including an interest coverage ratio and a debt-to-capitalization ratio. In addition to financial covenants, the Revolving Credit Facility contains covenants that, subject to exceptions, restrict debt incurrence, mergers and acquisitions, sales of assets, dividends and investments, liquidations and dissolutions, capital leases, transactions with affiliates and changes in lines of business. Borrowings under the Revolving Credit Facility may be used for general corporate purposes, the purchase of existing or new equipment, the purchase of the Company’s common stock, or for business acquisitions. As of December 31, 2016, the Company was in compliance with all Revolving Credit Facility covenants and had $225,986,000 of debt outstanding under the Revolving Credit Facility. The average borrowing under the Revolving Credit Facility during 2016 was $249,247,000, computing by averaging the daily balance, and the weighted average interest rate was 1.5%, computed by dividing the interest expense under the Revolving Credit Facility by the average Revolving Credit Facility borrowing. The Revolving Credit Facility includes a $25,000,000 commitment which may be used for standby letters of credit. Outstanding letters of credit under the Revolving Credit Facility were $2,518,000 as of December 31, 2016.

The Company has $500,000,000 of unsecured senior notes (“Senior Notes Series A” and “Senior Notes Series B”) with a group of institutional investors, consisting of $150,000,000 of 2.72% Senior Notes Series A due February 27, 2020 and $350,000,000 of 3.29% Senior Notes Series B due February 27, 2023. No principal payments are required until maturity. The Senior Notes Series A and Series B contain certain covenants on the part of the Company, including an interest coverage covenant, a debt-to-capitalization covenant and covenants relating to liens, asset sales and mergers, among others. The Senior Notes Series A and Series B also specify certain events of default, upon the occurrence of which the maturity of the notes may be accelerated, including failure to pay principal and interest, violation of covenants or default on other indebtedness, among others. As of December 31, 2016, the Company was in compliance with all Senior Notes Series A and Series B covenants and had $150,000,000 of Senior Notes Series A outstanding and $350,000,000 of Senior Notes Series B outstanding.

The Company has a $10,000,000 line of credit (“Credit Line”) with Bank of America, N.A. (“Bank of America”) for short-term liquidity needs and letters of credit, with a maturity date of June 30, 2017. The Credit Line allows the Company to borrow at an interest rate agreed to by Bank of America and the Company at the time each borrowing is made or continued. The Company had no borrowings outstanding under the Credit Line as December 31, 2016. Outstanding letters of credit under the Credit Line were $1,012,000 as of December 31, 2016.

The estimated fair value of total debt outstanding at December 31, 2016 and 2015 was $715,330,000 and $764,781,000, respectively, which differs from the carrying amount of $722,802,000 and $774,849,000, respectively, included in the consolidated financial statements. The fair value was determined using an income approach that relies on inputs such as yield curves.

Taxes on Income

12 Months Ended

Dec. 31, 2016

Taxes on Income [Abstract]

Taxes on Income

(6) Taxes on Income

Earnings before taxes on income and details of the provision for taxes on income for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	2016		2015		2014
Earnings before taxes on income — United States	$	227,746	$	361,712	$	454,390

Provision for taxes on income:
Federal:
Current	$	28,919	$	64,707	$	81,953
Deferred		49,685		59,582		72,920
State and local		6,338		9,453		14,909
	$	84,942	$	133,742	$	169,782

During the three years ended December 31, 2016, 2015 and 2014, the tax benefit (expense) related to the exercise of stock options and the issuance of restricted stock that were allocated directly to additional paid-in capital were $(824,000), $964,000 and $6,119,000, respectively.

The Company’s provision for taxes on income varied from the statutory federal income tax rate for the years ended December 31, 2016, 2015 and 2014 due to the following:

	2016			2015			2014
United States income tax statutory rate		35.0	%		35.0	%		35.0	%
State and local taxes, net of federal benefit		1.8			1.7			2.2
Other – net		.5			.3			.2
		37.3	%		37.0	%		37.4	%

The tax effects of temporary differences that give rise to significant portions of the current deferred tax assets and non-current deferred tax assets and liabilities at December 31, 2016 and 2015 were as follows (in thousands):

	2016			2015
Current deferred tax assets:
Compensated absences	$	739		$	829
Allowance for doubtful accounts		2,534			3,288
Insurance accruals		6,218			4,234
Other		4,113			3,372
	$	13,604		$	11,723

Non-current deferred tax assets and liabilities:
Deferred tax assets:
Postretirement health care benefits	$	2,234		$	2,501
Insurance accruals		2,910			3,410
Deferred compensation		11,124			10,534
Unrealized loss on defined benefit plans		28,832			25,245
Operating loss carryforwards		7,846			5,188
Other		21,622			20,702
Valuation allowances		(7,417)			(4,716)
		67,151			62,864

Deferred tax liabilities:
Property		(654,751	)		(604,737	)
Deferred state taxes		(54,812	)		(53,542	)
Pension benefits		(2,799	)		(8,471	)
Goodwill and other intangibles		(51,551	)		(44,185	)
Other		(22,295	)		(21,737	)
		(786,208	)		(732,672	)
	$	(719,057	)	$	(669,808	)

The Company has determined that it is more likely than not that all federal deferred tax assets at December 31, 2016 will be realized, including its operating loss carryforwards of $429,000 that expire in various amounts through 2030.

The valuation allowance for state deferred tax assets as of December 31, 2016 and 2015 was $7,417,000 and $4,716,000, respectively, related to the Company’s state net operating loss carryforwards based on the Company’s determination that it is more likely than not that the deferred tax assets will not be realized. Expiration of these state net operating loss carryforwards vary by state through 2036 and none will expire in fiscal 2017. Total deferred tax assets were $88,172,000 and $79,303,000 as of December 31, 2016 and 2015, respectively. Total deferred tax assets, net of valuation allowances, were $80,755,000 and $74,587,000 as of December 31, 2016 and 2015, respectively.

The Company or one of its subsidiaries files income tax returns in the United States federal jurisdiction and various state jurisdictions. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service for the 2013 through 2015 tax years. With few exceptions, the Company and its subsidiaries’ state income tax returns are open to audit under the statute of limitations for the 2010 through 2015 tax years.

As of December 31, 2016, the Company has provided a liability of $2,573,000 for unrecognized tax benefits related to various income tax issues which includes interest and penalties. The amount that would impact the Company’s effective tax rate, if recognized, is $1,737,000, with the difference between the total amount of unrecognized tax benefits and the amount that would impact the effective tax rate being primarily related to the federal tax benefit of state income tax items. It is not reasonably possible to determine if the liability for unrecognized tax benefits will significantly change prior to December 31, 2017 due to the uncertainty of possible examination results.

A reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014, is as follows (in thousands):

	2016			2015			2014
Balance at beginning of year	$	1,958		$	1,171		$	949
Additions based on tax positions related to the current year		187			339			470
Additions for tax positions of prior years		867			785			39
Reductions for tax positions of prior years		(441	)		(337	)		(287	)
Settlements		(552	)		—			—
Balance at end of year	$	2,019		$	1,958		$	1,171

The Company accounts for interest and penalties related to uncertain tax positions as part of its provision for federal and state income taxes. The Company recognized net expense of $88,000, $216,000 and $40,000 in interest and penalties for the years ended December 31, 2016, 2015 and 2014, respectively. The Company had $554,000, $522,000 and $306,000 of accrued liabilities for the payment of interest and penalties at December 31, 2016, 2015 and 2014, respectively.

Leases

12 Months Ended

Dec. 31, 2016

Leases [Abstract]

Leases

(7) Leases

The Company and its subsidiaries currently lease various facilities and equipment under a number of cancelable and noncancelable operating leases. Lease agreements for barges have terms from one to 12 years expiring at various dates through 2023. Lease agreements for towing vessels chartered by the Company have terms from 30 days to five years expiring at various dates through 2019; however, approximately half of the towing vessel charter agreements are for terms of one year or less. Total rental expense for the years ended December 31, 2016, 2015 and 2014 was as follows (in thousands):

	2016		2015		2014
Rental expense:
Marine equipment — barges	$	13,791	$	14,092	$	19,780
Marine equipment — towing vessels		137,609		143,067		136,331
Other buildings and equipment		11,182		9,383		9,146
Rental expense	$	162,582	$	166,542	$	165,257

Future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2016 were as follows (in thousands):

	Land, Buildings		Marine Equipment
	And Equipment		Barges		Towing Vessels		Total
2017	$	12,027	$	10,419	$	83,949	$	106,395
2018		11,049		8,718		20,532		40,299
2019		8,829		4,581		314		13,724
2020		7,508		3,813		—		11,321
2021		7,007		1,574		—		8,581
Thereafter		74,390		2,474		—		76,864
	$	120,810	$	31,579	$	104,795	$	257,184

Stock Award Plans

12 Months Ended

Dec. 31, 2016

Stock Award Plans [Abstract]

Stock Award Plans

(8) Stock Award Plans

The Company has share-based compensation plans which are described below. The compensation cost that has been charged against earnings for the Company’s stock award plans and the income tax benefit recognized in the statement of earnings for stock awards for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	2016		2015		2014
Compensation cost	$	11,675	$	11,104	$	11,591
Income tax benefit	$	4,378	$	4,120	$	4,358

The Company has an employee stock award plan for selected officers and other key employees which provides for the issuance of stock options, restricted stock and performance awards. The exercise price for each option equals the fair market value per share of the Company’s common stock on the date of grant. Substantially all stock options outstanding under the plan have terms of seven years and vest ratably over three years. No performance awards payable in stock have been awarded under the plan. At December 31, 2016, 1,987,512 shares were available for future grants under the employee plan and no outstanding stock options under the employee plan were issued with stock appreciation rights.

The following is a summary of the stock option activity under the employee plan described above for the years ended December 31, 2016, 2015 and 2014:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2013		379,604		$	55.42
Granted		75,204		$	98.91
Exercised		(119,276	)	$	42.07
Canceled or expired		(12,576	)	$	68.89
Outstanding at December 31, 2014		322,956		$	69.95
Granted		114,894		$	74.99
Exercised		—		$	—
Canceled or expired		(7,418	)	$	86.28
Outstanding at December 31, 2015		430,432		$	71.01
Granted		186,706		$	53.50
Exercised		—		$	—
Canceled or expired		(16,017	)	$	80.17
Outstanding at December 31, 2016		601,121		$	65.33

Under the employee plan, stock options exercisable were 321,942, 239,518 and 157,140 at December 31, 2016, 2015 and 2014, respectively.

The following table summarizes information about the Company’s outstanding and exercisable stock options under the employee plan at December 31, 2016:

		Options Outstanding								Options Exercisable
Range of Exercise Prices		Number Outstanding		Weighted Average Remaining Contractual Life in Years		Weighted Average Exercise Price		Aggregated Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregated Intrinsic Value
$	31.35 – $36.35		16,910		0.1	$	32.82				16,910	$	32.82
$	46.74 – $51.23		212,335		4.8	$	50.03				56,629	$	46.74
$	64.89 – $74.99		302,735		4.1	$	70.29				202,309	$	69.51
$	93.64 – $96.85		33,987		4.1	$	94.31				22,658	$	94.31
$	101.46 – $104.37		35,154		4.2	$	102.60				23,436	$	102.60
$	31.35 – $104.37		601,121		4.2	$	65.33	$	4,175,000		321,942	$	67.73	$	1,747,000

The following is a summary of the restricted stock award activity under the employee plan described above for the years ended December 31, 2016, 2015 and 2014:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2013		399,278		$	54.92
Granted		97,706		$	97.46
Vested		(141,870	)	$	45.64
Forfeited		(33,661	)	$	63.56
Nonvested balance at December 31, 2014		321,453		$	71.04
Granted		122,740		$	75.04
Vested		(113,958	)	$	60.73
Forfeited		(18,508	)	$	82.00
Nonvested balance at December 31, 2015		311,727		$	75.73
Granted		190,610		$	53.56
Vested		(105,109	)	$	69.93
Forfeited		(19,573	)	$	76.06
Nonvested balance at December 31, 2016		377,655		$	66.14

The Company has a stock award plan for nonemployee directors of the Company which provides for the issuance of stock options and restricted stock. The director plan provides for automatic grants of restricted stock to nonemployee directors after each annual meeting of stockholders. In addition, the director plan allows for the issuance of stock options or restricted stock in lieu of cash for all or part of the annual director fee at the option of the director. The exercise prices for all options granted under the plan are equal to the fair market value per share of the Company’s common stock on the date of grant. The terms of the options are ten years. The restricted stock issued after each annual meeting of stockholders vests six months after the date of grant. Options granted and restricted stock issued in lieu of cash director fees vest in equal quarterly increments during the year to which they relate. At December 31 2016, 522,457 shares were available for future grants under the director plan. The director stock award plan is intended as an incentive to attract and retain qualified independent directors.

The following is a summary of the stock option activity under the director plan described above for the years ended December 31, 2016, 2015, and 2014:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2013		320,322		$	50.64
Granted		42,000		$	99.52
Exercised		(63,988	)	$	39.08
Outstanding at December 31, 2014		298,334		$	60.01
Exercised		(77,905	)	$	47.65
Outstanding at December 31, 2015		220,429		$	64.37
Exercised		(9,000	)	$	35.72
Canceled or expired		(6,000	)	$	99.52
Outstanding at December 31, 2016		205,429		$	64.60

Under the director plan, options exercisable were 205,429, 220,429 and 298,334 at December 31, 2016, 2015 and 2014, respectively.

The following table summarizes information about the Company’s outstanding and exercisable stock options under the director plan at December 31, 2016:

		Options Outstanding								Options Exercisable
Range of Exercise Prices		Number Outstanding		Weighted Average Remaining Contractual Life in Years		Weighted Average Exercise Price		Aggregate Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregate Intrinsic Value
$	29.60 – $36.82		21,000		0.9	$	32.69				21,000	$	32.69
$	41.24 – $56.45		71,276		2.7	$	52.34				71,276	$	52.34
$	61.89 – $62.48		41,153		4.8	$	62.34				41,153	$	62.34
$	75.17 – $99.52		72,000		5.7	$	87.35				72,000	$	87.35
$	29.60 – $99.52		205,429		4.0	$	64.60	$	1,891,000		205,429	$	64.60	$	1,891,000

The following is a summary of the restricted stock award activity under the director plan described above for the years ended December 31, 2016, 2015 and 2014:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2013		384		$	75.65
Granted		8,160		$	99.52
Vested		(8,252	)	$	98.41
Nonvested balance at December 31, 2014		292		$	99.52
Granted		20,350		$	78.52
Vested		(18,851	)	$	79.77
Nonvested balance at December 31, 2015		1,791		$	68.73
Granted		23,074		$	64.89
Vested		(24,518	)	$	65.17
Nonvested balance at December 31, 2016		347		$	64.89

The total intrinsic value of all stock options exercised under all of the Company’s plans was $266,000, $2,555,000 and $11,671,000 for the years ended December 31, 2016, 2015 and 2014, respectively. The actual tax benefit realized for tax deductions from stock option exercises was $100,000, $948,000 and $4,388,000 for the years ended December 31, 2016, 2015 and 2014, respectively.

The total intrinsic value of all the restricted stock vestings under all of the Company’s plans was $6,928,000, $10,270,000 and $14,847,000 for the years ended December 31, 2016, 2015 and 2014, respectively. The actual tax benefit realized for tax deductions from restricted stock vestings was $2,598,000, $3,810,000 and $5,583,000 for the years ended December 31, 2016, 2015 and 2014, respectively.

As of December 31, 2016, there was $3,422,000 of unrecognized compensation cost related to nonvested stock options and $18,055,000 related to restricted stock. The stock options are expected to be recognized over a weighted average period of approximately 1.4 years and restricted stock over approximately 3.1 years. The total fair value of stock options vested was $2,495,000, $2,180,000 and $3,759,000 during the years ended December 31, 2016, 2015 and 2014, respectively. The fair value of the restricted stock vested was $6,928,000, $10,270,000 and $14,847,000 for the years ended December 31, 2016, 2015 and 2014, respectively.

The weighted average per share fair value of stock options granted during the years ended December 31, 2016, 2015 and 2014 was $17.30, $25.18 and $36.05, respectively. The fair value of the stock options granted during the years ended December 31, 2016, 2015 and 2014 was $3,231,000, $2,893,000 and $4,226,000, respectively. The Company currently uses treasury stock shares for restricted stock grants and stock option exercises. The fair value of each stock option was determined using the Black-Scholes option pricing model. The key input variables used in valuing the stock options during the years ended December 31, 2016, 2015 and 2014 were as follows:

	2016			2015			2014
Dividend yield	None			None			None
Average risk-free interest rate		1.5	%		1.3	%		2.0	%
Stock price volatility		30	%		33	%		33	%
Estimated option term		Six years			Six years			Six years or seven years

- Definition

The entire disclosure for compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details.

+ References + Details

Retirement Plans

12 Months Ended

Dec. 31, 2016

Retirement Plans [Abstract]

Retirement Plans

(9) Retirement Plans

The Company sponsors a defined benefit plan for its inland vessel personnel and shore based tankermen. The plan benefits are based on an employee’s years of service and compensation. The plan assets consist primarily of equity and fixed income securities.

The fair value of plan assets was $257,517,000 and $243,588,000 at December 31, 2016 and 2015 respectively. As of December 31, 2016 and 2015, these assets were allocated among asset categories as follows:

Asset Category	2016			2015			Current Minimum, Target and Maximum Allocation Policy
U.S. equity securities		51	%		50	%		30% — 50%— 70	%
International equity securities		19	%		18	%		0% — 20%— 30	%
Debt securities		30	%		28	%		15% — 30%— 55	%
Cash and cash equivalents		—	%		4	%		0% — 0%— 5	%
		100	%		100	%

The plan assets are invested entirely in common collective trusts. These instruments are public investment vehicles valued using the net asset value provided by the administrator of the fund. The net asset value is classified within Level 2 of the valuation hierarchy as set forth in the accounting guidance for fair value measurements because the net asset value price is quoted on an inactive private market although the underlying investments are traded on an active market.

The Company’s investment strategy focuses on total return on invested assets (capital appreciation plus dividend and interest income). The primary objective in the investment management of assets is to achieve long-term growth of principal while avoiding excessive risk. Risk is managed through diversification of investments within and among asset classes, as well as by choosing securities that have an established trading and underlying operating history.

The Company makes various assumptions when determining defined benefit plan costs including, but not limited to, the current discount rate and the expected long-term return on plan assets. Discount rates are determined annually and are based on a yield curve that consists of a hypothetical portfolio of high quality corporate bonds with maturities matching the projected benefit cash flows. The Company assumed that plan assets would generate a long-term rate of return of 7.0% and 7.5% in 2016 and 2015, respectively. The Company developed its expected long-term rate of return assumption by evaluating input from investment consultants comparing historical returns for various asset classes with its actual and targeted plan investments. The Company believes that its long-term asset allocation, on average, will approximate the targeted allocation.

The Company’s pension plan funding strategy has historically been to contribute an amount equal to the greater of the minimum required contribution under ERISA or the amount necessary to fully fund the plan on an accumulated benefit obligation (“ABO”) basis at the end of the fiscal year. The ABO is based on a variety of demographic and economic assumptions, and the pension plan assets’ returns are subject to various risks, including market and interest rate risk, making an accurate prediction of the pension plan contribution difficult. The Company’s pension plan funding was 94% of the pension plan’s ABO at December 31, 2016.

The Company sponsors an unfunded defined benefit health care plan that provides limited postretirement medical benefits to employees who met minimum age and service requirements, and to eligible dependents. The plan limits cost increases in the Company’s contribution to 4% per year. The plan is contributory, with retiree contributions adjusted annually. The plan eliminated coverage for future retirees as of December 31, 2011. The Company also has an unfunded defined benefit supplemental executive retirement plan (“SERP”) that was assumed in an acquisition in 1999. That plan ceased to accrue additional benefits effective January 1, 2000.

The following table presents the change in benefit obligation and plan assets for the Company’s defined benefit plans and postretirement benefit plan (in thousands):

													Other Postretirement Benefits
	Pension Benefits												Postretirement
	Pension Plan						SERP						Welfare Plan
	2016			2015			2016			2015			2016			2015
Change in benefit obligation
Benefit obligation at beginning of year	$	297,325		$	315,075		$	1,526		$	1,637		$	891		$	1,264
Service cost		13,402			14,683			—			—			—			—
Interest cost		14,123			13,302			65			64			29			36
Actuarial loss (gain)		19,120			(39,474	)		12			(30	)		(198	)		(321	)
Gross benefits paid		(6,794	)		(6,261	)		(146	)		(145	)		(47	)		(88	)
Benefit obligation at end of year	$	337,176		$	297,325		$	1,457		$	1,526		$	675		$	891

Accumulated benefit obligation at end of year	$	272,591		$	238,775		$	1,457		$	1,526		$	675		$	891

Weighted-average assumption used to determine benefit obligation at end of year
Discount rate		4.2	%		4.5	%	4.2	%	4.5	%	4.2	%	4.5	%
Rate of compensation increase	Service- based table			Service- based table			—		—		—		—
Health care cost trend rate
Initial rate		—			—		—		—		7.0	%	6.5	%
Ultimate rate		—			—		—		—		5.0	%	5.0	%
Years to ultimate		—			—		—		—		2021		2019

Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation
Increase	$	—	$	—	$	—	$	—	$	74		$	107
Decrease		—		—		—		—		(64	)		(93	)

Change in plan assets
Fair value of plan assets at beginning of year	$	243,588		$	242,275		$	—		$	—		$	—		$	—
Actual return on plan assets		20,723			(2,426	)		—			—			—			—
Employer contribution		—			10,000			146			145			47			88
Gross benefits paid		(6,794	)		(6,261	)		(146	)		(145	)		(47	)		(88	)
Fair value of plan assets at end of year	$	257,517		$	243,588		$	—		$	—		$	—		$	—

The following table presents the funded status and amounts recognized in the Company’s consolidated balance sheet for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2016 and 2015 (in thousands):

													Other Postretirement Benefits
	Pension Benefits												Postretirement
	Pension Plan						SERP						Welfare Plan
	2016			2015			2016			2015			2016			2015
Funded status at end of year
Fair value of plan assets	$	257,517		$	243,588		$	—		$	—		$	—		$	—
Benefit obligations		(337,176	)		(297,325	)		(1,457	)		(1,526	)		(675	)		(891	)
Funded status and amount recognized at end of year	$	(79,659	)	$	(53,737	)	$	(1,457	)	$	(1,526	)	$	(675	)	$	(891	)

Amounts recognized in the consolidated balance sheets
Noncurrent asset	$	—		$	—		$	—		$	—		$	—		$	—
Current liability		—			—			(150	)		(149	)		(56	)		(68	)
Long-term liability		(79,659	)		(53,737	)		(1,307	)		(1,377	)		(619	)		(823	)

Amounts recognized in accumulated other comprehensive income
Net actuarial loss (gain)	$	87,658	$	77,940	$	494	$	508	$	(5,773	)	$	(6,319	)
Prior service cost (credit)		—		—		—		—		—			—
Accumulated other compensation income	$	87,658	$	77,940	$	494	$	508	$	(5,773	)	$	(6,319	)

The projected benefit obligation and fair value of plan assets for pension plans with a projected benefit obligation in excess of plan assets at December 31, 2016 and 2015 were as follows (in thousands):

	Pension Benefits
	Pension Plan				SERP
	2016		2015		2016		2015
Projected benefit obligation in excess of plan assets
Projected benefit obligation at end of year	$	337,176	$	297,325	$	1,457	$	1,526
Fair value of plan assets at end of year		257,517		243,588		—		—

The projected benefit obligation, accumulated benefit obligation and fair value of plan assets for pension plans with an accumulated benefit obligation in excess of plan assets at December 31, 2016 and 2015 were as follows (in thousands):

	Pension Benefits
	Pension Plan				SERP
	2016		2015		2016		2015
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation at end of year	$	337,176	$	—	$	1,457	$	1,526
Accumulated benefit obligation at end of year		272,591		—		1,457		1,526
Fair value of plan assets at end of year		257,517		—		—		—

The following tables presents the expected cash flows for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2016 and 2015 (in thousands):

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2016		2015		2016		2015		2016		2015
Expected employer contributions
First year	$	—	$	—	$	153	$	152	$	50	$	70

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2016		2015		2016		2015		2016		2015
Expected benefit payments (gross)
Year one	$	8,032	$	7,678	$	153	$	152	$	58	$	81
Year two		8,835		8,298		157		157		58		86
Year three		9,646		9,013		155		154		58		86
Year four		10,400		9,748		151		152		58		86
Year five		11,201		10,415		148		149		57		85
Next five years		70,419		63,860		514		608		199		341

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2016		2015		2016		2015		2016			2015
Expected federal subsidy
Year one	$	—	$	—	$	—	$	—	$	(7	)	$	(11	)
Year two		—		—		—		—		(7	)		(11	)
Year three		—		—		—		—		(7	)		(11	)
Year four		—		—		—		—		(7	)		(12	)
Year five		—		—		—		—		(7	)		(12	)
Next five years		—		—		—		—		(33	)		(55	)

The components of net periodic benefit cost and other changes in plan assets and benefit obligations recognized in other comprehensive income for the Company’s defined benefit plans for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	Pension Benefits
	Pension Plan									SERP
	2016			2015			2014			2016			2015			2014
Components of net periodic benefit cost
Service cost	$	13,402		$	14,683		$	10,645		$	—		$	—		$	—
Interest cost		14,123			13,302			12,839			65			64			73
Expected return on plan assets		(16,805	)		(17,921	)		(18,858	)		—			—			—
Amortization:
Actuarial loss		5,484			7,728			701			26			28			16
Prior service credit		—			—			—			—			—			—
Net periodic benefit cost		16,204			17,792			5,327			91			92			89

Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		15,203			(19,127	)		72,737			12			(30	)		180
Recognition of actuarial loss		(5,484	)		(7,728	)		(701	)		(26	)		(28	)		(16	)
Recognition of prior service credit		—			—			—			—			—			—
Total recognized in other comprehensive income		9,719			(26,855	)		72,036			(14	)		(58	)		164

Total recognized in net periodic benefit cost and other comprehensive income	$	25,923		$	(9,063	)	$	77,363		$	77		$	34		$	253

Weighted average assumptions used to determine net periodic benefit cost
Discount rate		4.5	%	4.1	%	5.0	%	4.5	%	4.1	%	5.0	%
Expected long-term rate of return on plan assets		7.0	%	7.5	%	7.5	%	—		—		—
Rate of compensation increase	Service- based table			4.25	%	4.25	%	—		—		—

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2017 are as follows (in thousands):

	Pension Benefits
	Pension Plan		SERP
Actuarial loss	$	5,477	$	28
Prior service credit		—		—
	$	5,477	$	28

The components of net periodic benefit cost and other changes in benefit obligations recognized in other comprehensive income for the Company’s postretirement benefit plan for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
	2016			2015			2014
Components of net periodic benefit cost
Service cost	$	—		$	—		$	—
Interest cost		29			36			110
Amortization:
Actuarial gain		(747	)		(793	)		(649	)
Prior service cost		—			—			—
Net periodic benefit cost		(718	)		(757	)		(539	)

Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial gain		(198	)		(322	)		(1,065	)
Recognition of actuarial gain		747			793			649
Recognition of prior service cost		—			—			—
Adjustment for actual Medicare Part D reimbursement		(3	)		(3	)		(8	)
Total recognized in other comprehensive income		546			468			(424	)

Total recognized in net periodic benefit cost and other comprehensive income	$	(172	)	$	(289	)	$	(963	)

Weighted average assumptions used to determine net periodic benefit cost
Discount rate	4.5	%	4.1	%	5.0	%
Health care cost trend rate:
Initial rate	6.5	%	7.0	%	7.0	%
Ultimate rate	5.0	%	5.0	%	5.0	%
Years to ultimate	2019		2019		2018

Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost
Increase	$	4		$	5		$	7
Decrease		(3	)		(4	)		(6	)

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2017 are as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
Actuarial gain	$	(668	)
Prior service cost		—
	$	(668	)

The Company also contributes to a multiemployer pension plan pursuant to a collective bargaining agreement which covers certain vessel crew members of its coastal operations and expires on April 30, 2018. The Company began participation in the Seafarers Pension Trust (“SPT”) with the Penn Maritime, Inc. acquisition on December 14, 2012.

Contributions to the SPT are made currently based on a per day worked basis and charged to expense as incurred and included in costs of sales and operating expenses in the consolidated statement of earnings. During 2016 and 2015, the Company made contributions of $877,000 and $1,202,000, respectively, to the SPT. The Company’s contributions to the SPT exceeded 5% of total contributions to the SPT in 2015. Total contributions for 2016 are not yet available. The Company did not pay any material surcharges in 2015 or 2016.

The federal identification number of the SPT is 13-6100329 and the Certified Zone Status is Green at December 31, 2015. The Company’s future minimum contribution requirements under the SPT are unavailable because actuarial reports for the 2016 plan year are not yet complete and such contributions are subject to negotiations between the employers and the unions. The SPT was neither in endangered or critical status for the 2015 plan year, the latest period for which a report is available, as the funded status was in excess of 100%. Based on an actuarial valuation performed as of December 31, 2015, there would be no withdrawal liability if the Company chose to withdraw from the SPT although the Company currently has no intention of terminating its participation in the SPT.

In addition to the defined benefit plans, the Company sponsors various defined contribution plans for substantially all employees. The aggregate contributions to the plans were $18,213,000, $24,077,000 and $23,356,000 in 2016, 2015 and 2014, respectively.

Other Comprehensive Income

12 Months Ended

Dec. 31, 2016

Other Comprehensive Income [Abstract]

Other Comprehensive Income

(10) Other Comprehensive Income

The Company’s changes in other comprehensive income for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	2016									2015							2014
	Gross Amount			Income Tax (Provision) Benefit			Net Amount			Gross Amount		Income Tax (Provision) Benefit			Net Amount		Gross Amount			Income Tax (Provision) Benefit			Net Amount
Pension and postretirement benefits (a):
Amortization of net actuarial loss	$	4,763		$	(1,825	)	$	2,938		$	6,963	$	(2,667	)	$	4,296	$	68		$	(26	)	$	42
Actuarial gains (losses)		(15,013	)		5,754			(9,259	)		19,482		(7,456	)		12,026		(71,843	)		27,507			(44,336	)

Foreign currency translation adjustments		—			—			—			29		—			29		(35	)		—			(35	)

Change in fair value of derivative instruments (b):
Unrealized gains (losses)		—			—			—			—		—			—		24			(9	)		15
Reclassified to net earnings		—			—			—			—		—			—		121			(51	)		70
Total	$	(10,250	)	$	3,929		$	(6,321	)	$	26,474	$	(10,123	)	$	16,351	$	(71,665	)	$	27,421		$	(44,244	)

(a)	Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 9 – Retirement Plans)

(b)	Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in costs of sales and operating expenses.

Earnings Per Share

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Earnings Per Share

(11) Earnings Per Share

The following table presents the components of basic and diluted earnings per share for the years ended December 31, 2016, 2015 and 2014 (in thousands, except per share amounts):

	2016			2015			2014
Net earnings attributable to Kirby	$	141,406		$	226,684		$	282,006
Undistributed earnings allocated to restricted shares		(999	)		(1,345	)		(1,643	)
Income available to Kirby common stockholders — basic		140,407			225,339			280,363
Undistributed earnings allocated to restricted shares		999			1,345			1,643
Undistributed earnings reallocated to restricted shares		(997	)		(1,343	)		(1,637	)
Income available to Kirby common stockholders — diluted	$	140,409		$	225,341		$	280,369

Shares outstanding:
Weighted average common stock issued and outstanding		53,834			55,056			57,006
Weighted average unvested restricted stock		(380	)		(327	)		(332	)
Weighted average common stock outstanding — basic		53,454			54,729			56,674
Dilutive effect of stock options		58			97			193
Weighted average common stock outstanding — diluted		53,512			54,826			56,867
Net earnings per share attributable to Kirby common stockholders:
Basic	$	2.63		$	4.12		$	4.95

Diluted	$	2.62		$	4.11		$	4.93

Certain outstanding options to purchase approximately 240,000, 227,000 and 75,000 shares of common stock were excluded in the computation of diluted earnings per share as of December 31, 2016, 2015 and 2014, respectively, as such stock options would have been antidilutive.

Quarterly Results (Unaudited)

12 Months Ended

Dec. 31, 2016

Quarterly Results (Unaudited) [Abstract]

Quarterly Results (Unaudited)

(12) Quarterly Results (Unaudited)

The unaudited quarterly results for the year ended December 31, 2016 were as follows (in thousands, except per share amounts):

	Three Months Ended
	March 31, 2016			June 30, 2016			September 30, 2016			December 31, 2016
Revenues	$	458,733		$	441,582		$	434,708		$	435,650
Costs and expenses		393,399			374,868			378,400			378,684
Gain (loss) on disposition of assets		67			94			(122	)		(166	)
Operating income		65,401			66,808			56,186			56,800
Other income (expense)		135			179			(120	)		47
Interest expense		(4,193	)		(4,513	)		(4,507	)		(4,477	)
Earnings before taxes on income		61,343			62,474			51,559			52,370
Provision for taxes on income		(22,859	)		(23,365	)		(19,206	)		(19,512	)
Net earnings		38,484			39,109			32,353			32,858
Less: Net earnings attributable to noncontrolling interests		(385	)		(167	)		(343	)		(503	)
Net earnings attributable to Kirby	$	38,099		$	38,942		$	32,010		$	32,355

Net earnings per share attributable to Kirby common stockholders:
Basic	$	0.71		$	0.72		$	0.59		$	0.60
Diluted	$	0.71		$	0.72		$	0.59		$	0.60

The unaudited quarterly results for the year ended December 31, 2015 were as follows (in thousands, except per share amounts):

	Three Months Ended
	March 31, 2015			June 30, 2015			September 30, 2015			December 31, 2015
Revenues	$	587,673		$	543,156		$	532,565		$	484,138
Costs and expenses		486,136			445,113			437,115			400,178
Gain (loss) on disposition of assets		1,555			91			(400	)		426
Operating income		103,092			98,134			95,050			84,386
Other income (expense)		60			(303	)		22			9
Interest expense		(5,250	)		(4,759	)		(4,449	)		(4,280	)
Earnings before taxes on income		97,902			93,072			90,623			80,115
Provision for taxes on income		(36,491	)		(34,696	)		(33,512	)		(29,043	)
Net earnings		61,411			58,376			57,111			51,072
Less: Net earnings attributable to noncontrolling interests		(333	)		(301	)		(268	)		(384	)
Net earnings attributable to Kirby	$	61,078		$	58,075		$	56,843		$	50,688

Net earnings per share attributable to Kirby common stockholders:
Basic	$	1.09		$	1.04		$	1.04		$	0.94
Diluted	$	1.09		$	1.04		$	1.04		$	0.94

Quarterly basic and diluted earnings per share may not total to the full year per share amounts, as the weighted average number of shares outstanding for each quarter fluctuates as a result of the assumed exercise of stock options.

Contingencies and Commitments	12 Months Ended
Contingencies and Commitments	Dec. 31, 2016
Contingencies and Commitments [Abstract]
Contingencies and Commitments	(13) Contingencies and Commitments In 2009, the Company was named a Potentially Responsible Party (“PRP”) in addition to a group of approximately 250 named PRPs under the Comprehensive Environmental Response, Compensation and Liability Act of 1981 (“CERCLA”) with respect to a Superfund site, the Portland Harbor Superfund site (“Portland Harbor”) in Portland, Oregon. The site was declared a Superfund site in December 2000 as a result of historical heavily industrialized use due to manufacturing, shipbuilding, petroleum storage and distribution, metals salvaging, and electrical power generation activities which led to contamination of Portland Harbor, an urban and industrial reach of the lower Willamette River located immediately downstream of downtown Portland. The Company’s involvement arises from four spills at the site after it was declared a Superfund site, as a result of predecessor entities’ actions in the area. To date, there is no information suggesting the extent of the costs or damages to be claimed from the 250 notified PRPs. Based on the nature of the involvement at the Portland Harbor site, the Company believes its potential contribution is de minimis; however, to date neither the Environmental Protection Agency (“EPA”) nor the named PRPs have performed an allocation of potential liability in connection with the site nor have they provided costs and expenses in connection with the site. In January 2015, the Company was named as a defendant in a Complaint filed in the U.S. District Court of the Southern District of Texas, USOR Site PRP Group vs. A&M Contractors, USES, Inc. et al. This is a civil action pursuant to the provisions of CERCLA and the Texas Solid Waste Disposal Act for recovery of past and future response costs incurred and to be incurred by the USOR Site PRP Group for response activities at the U.S. Oil Recovery Superfund Site. The property was a former sewage treatment plant owned by defendant City of Pasadena, Texas from approximately 1945 until it was acquired by U.S. Oil Recovery in January 2009. Throughout its operating life, the U.S. Oil Recovery facility portion of the USOR Site received and performed wastewater pretreatment of municipal and Industrial Class I and Class II wastewater, characteristically hazardous waste, used oil and oily sludges, and municipal solid waste. Associated operations were conducted at the MCC Recycling facility portion of the USOR Site after it was acquired by U.S. Oil Recovery from the City of Pasadena in January 2009. Initially, the plaintiff stayed prosecution of the case pending responses to initial settlement demands. In January 2016, the Company filed responsive pleadings in this matter. Based on the nature of the involvement at the USOR Site, the Company believes its potential contribution is de minimis; however, to date neither the EPA nor the named PRPs have performed an allocation of potential liability in connection with the site nor have they provided costs and expenses in connection with the site. On October 13, 2016, the Company, as a successor to Hollywood Marine, Inc., was issued a General Notice under CERCLA in which it was named as a PRP for liabilities associated with the SBA Shipyard Site located near Jennings, Louisiana (“Site”). The Site was added to the EPA’s National Priorities List of sites under CERCLA in September 2016. SBA used the facility for construction, repair, retrofitting, sandblasting, and cleaning and painting of barges beginning in 1965. Three barge slips and a dry dock are located off the Mermentau River. The slips were used to dock barges during cleaning or repair. In 2001, a group of PRPs that had been former customers of the SBA Shipyard facility formed an organization called the SSIC Remediation, LLC (hereinafter, “the Companies”) to address removal actions at the Site. In 2002, EPA approved an Interim Measures/Removal Action of Hazardous/Principal Threat Wastes at SBA Shipyards, Inc. (pursuant to RCRA Section 3008(h)) that was proposed by SBA Shipyard and the Companies. Interim removal activities were conducted from March 2001 through January 2005 under an EPA 2002 Order and Agreement. In September 2012, the Louisiana Department of Environmental Quality requested EPA address the SBA Shipyard site under CERCLA authority. The Company is investigating its activities in connection with Site. With respect to the above sites, the Company has recorded reserves, if applicable, for its estimated potential liability for its portion of the EPA’s past costs claim based on information developed to date including various factors such as the Company’s liability in proportion to other responsible parties and the extent to which such costs are recoverable from third parties. On October 13, 2016, the tug Nathan E. Stewart and barge DBL 55, an articulated tank barge and tugboat unit, ran aground at the entrance to Seaforth Channel on Atholone Island, British Columbia. The grounding resulted in a breach of a portion of the Nathan E. Stewart’s fuel tanks causing a discharge of diesel fuel into the water. The USCG and the National Transportation Safety Board (“NTSB”) designated the Company as a party of interest in their investigation as to the cause of the incident. The Canadian authorities including Transport Canada and the Canadian Transportation Safety Board are also investigating the cause of the incident. The Company is subject to claims from third parties as well as the provincial and federal government as a result of the incident. The Company has various insurance policies covering liabilities including pollution, property, marine and general liability and believes that it has satisfactory insurance coverage for the cost of cleanup and salvage operations as well as other potential liabilities arising from the incident. On March 22, 2014, two tank barges and a towboat (the M/V Miss Susan), owned by Kirby Inland Marine, LP, a wholly owned subsidiary of the Company, were involved in a collision with the M/S Summer Wind on the Houston Ship Channel near Texas City, Texas. The lead tank barge was damaged in the collision resulting in a discharge of intermediate fuel oil from one of its cargo tanks. The USCG and the NTSB named the Company and the Captain of the M/V Miss Susan, as well as the owner and the pilot of the M/S Summer Wind, as parties of interest in their investigation as to the cause of the incident. Sea Galaxy Ltd is the owner of the M/S Summer Wind. The Company is participating in the natural resource damage assessment and restoration process with federal and state government natural resource trustees. The Company and the owner of the M/S Summer Wind filed actions in the U.S. District Court for the Southern District of Texas seeking exoneration from or limitation of liability relating to the foregoing incident as provided for in the federal rules of procedure for maritime claims. The two actions were consolidated for procedural purposes since they both arise out of the same occurrence. Multiple parties filed claims in limitation seeking various damages under the Oil Pollution Act of 1990 (“OPA”), including claims for business interruption, loss of profit and loss of use of natural resources (OPA claimants). On November 2, 2016, the Company, the M/S Summer Wind and its owners and the OPA claimants entered into a settlement agreement pursuant to which the parties have resolved their respective claims against one another. The dismissal of the OPA claims was entered by the Court on November 14, 2016. The Company has also been named as a defendant in a civil action by two crewmembers of the M/V Miss Susan, alleging damages under the general maritime law and the Jones Act. The Company is defending the civil action in the proceeding in Galveston Civil District Court. The Company is processing claims that have not been filed in the limitation matter that are properly presented, documented and recoverable under OPA. On September 13, 2016, the Company entered into a Consent Decree with the Department of Justice (“DOJ”) to settle civil penalty provisions under Section 311(b) of the Clean Water Act involving the discharge of intermediate fuel oil as a result of the collision between the tank barge and the M/S Summer Wind. Under the Consent Decree, the Company agreed to pay a civil penalty of $4,900,000 and undertake certain actions relating to navigation procedures. On September 27, 2016, the DOJ filed the proposed Consent Decree with the U.S. District Court for the Southern District of Texas along with an Original Complaint setting out the allegations that the Company is civilly liable for violation of Section 311(b) of the Clean Water Act. The Consent Decree was approved by the federal court on November 14, 2016. The Company believes it has adequate insurance coverage for pollution, marine and other potential liabilities arising from the incident. The Company believes it has accrued adequate reserves for the incident and does not expect the incident to have a material adverse effect on its business or financial condition. In addition, the Company is involved in various legal and other proceedings which are incidental to the conduct of its business, none of which in the opinion of management will have a material effect on the Company’s financial condition, results of operations or cash flows. Management believes that it has recorded adequate reserves and believes that it has adequate insurance coverage or has meritorious defenses for these other claims and contingencies. Certain Significant Risks and Uncertainties. The preparation of financial statements in conformity with United States generally accepted accounting principles requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. However, in the opinion of management, the amounts would be immaterial. The customer base of the marine transportation segment includes major industrial petrochemical and chemical manufacturers, refining companies and agricultural chemical manufacturers operating in the United States. During the first nine months of 2016, approximately 80% of marine transportation’s inland revenues were from movements of such products under term contracts and during the 2016 fourth quarter, approximately 75% of inland marine transportation revenues were under term contracts, typically ranging from one year to five years, some with renewal options. During 2016, approximately 80% of the marine transportation’s coastal revenues were under term contracts. While the manufacturing and refining companies have generally been customers of the Company for numerous years (some as long as 40 years) and management anticipates a continuing relationship, there is no assurance that any individual contract will be renewed. No single customer of the marine transportation segment accounted for 10% of the Company’s revenues in 2016, 2015 and 2014. Major customers of the diesel engine services segment include inland and offshore barge operators, oilfield service companies, oil and gas operators and producers, offshore fishing companies, marine and on-highway transportation companies, the United States government, and power generation, nuclear and industrial companies. The segment operates as an authorized distributor in 17 eastern states, nine western states and the Caribbean, and as non-exclusive authorized service centers for EMD throughout the rest of the United States for marine and power generation applications. The diesel engine services segment’s relationship with EMD has been maintained for 51 years. The segment also operates factory-authorized full service marine dealerships for Cummins, Detroit Diesel and John Deere high-speed diesel engines and Twin Disc marine gears in the Gulf Coast region, as well as an authorized marine dealer for Caterpillar in Alabama, Kentucky, Louisiana and New Jersey. United has maintained continuous exclusive distribution rights for MTU and Allison since 1946. United is one of MTU’s top five distributors of MTU off-highway engines in North America with exclusive distribution rights in Oklahoma, Arkansas, Louisiana and Mississippi. In addition, as a distributor of Allison transmission products, United has distribution rights in Oklahoma, Arkansas and Louisiana. Finally, United is also the distributor for parts service and warranty on Daimler engines and related equipment in Oklahoma, Arkansas and Louisiana. The results of the diesel engine services segment are largely tied to the industries it serves and, therefore, can be influenced by the cycles of such industries. No single customer of the diesel engine services segment accounted for 10% of the Company’s revenues in 2016, 2015 and 2014. Weather can be a major factor in the day-to-day operations of the marine transportation segment. Adverse weather conditions, such as high or low water, tropical storms, hurricanes, tsunamis, fog and ice, can impair the operating efficiencies of the marine fleet. Shipments of products can be delayed or postponed by weather conditions, which are totally beyond the control of the Company. Adverse water conditions are also factors which impair the efficiency of the fleet and can result in delays, diversions and limitations on night passages, and dictate horsepower requirements and size of tows. Additionally, much of the inland waterway system is controlled by a series of locks and dams designed to provide flood control, maintain pool levels of water in certain areas of the country and facilitate navigation on the inland river system. Maintenance and operation of the navigable inland waterway infrastructure is a government function handled by the Army Corps of Engineers with costs shared by industry. Significant changes in governmental policies or appropriations with respect to maintenance and operation of the infrastructure could adversely affect the Company. The Company’s marine transportation segment is subject to regulation by the USCG, federal laws, state laws and certain international conventions, as well as numerous environmental regulations. The Company believes that additional safety, environmental and occupational health regulations may be imposed on the marine industry. There can be no assurance that any such new regulations or requirements, or any discharge of pollutants by the Company, will not have an adverse effect on the Company. The Company’s marine transportation segment competes principally in markets subject to the Jones Act, a federal cabotage law that restricts domestic marine transportation in the United States to vessels built and registered in the United States, and manned and owned by United States citizens. The Jones Act cabotage provisions occasionally come under attack by interests seeking to facilitate foreign flag competition in trades reserved for domestic companies and vessels under the Jones Act. The Company believes that continued efforts will be made to modify or eliminate the cabotage provisions of the Jones Act. If such efforts are successful, certain elements could have an adverse effect on the Company. The Company has issued guaranties or obtained standby letters of credit and performance bonds supporting performance by the Company and its subsidiaries of contractual or contingent legal obligations of the Company and its subsidiaries incurred in the ordinary course of business. The aggregate notional value of these instruments is $13,983,000 at December 31, 2016, including $3,799,000 in letters of credit and $10,184,000 in performance bonds. All of these instruments have an expiration date within three years. The Company does not believe demand for payment under these instruments is likely and expects no material cash outlays to occur in connection with these instruments.

Segment Data

12 Months Ended

Dec. 31, 2016

Segment Data [Abstract]

Segment Data

(14) Segment Data

The Company’s operations are aggregated into two reportable business segments as follows:

Marine Transportation — Provides marine transportation principally by United States flag vessels of liquid cargoes throughout the United States inland waterway system, along all three United States coasts, in Alaska and Hawaii and, to a lesser extent, in United States coastal transportation of dry-bulk cargoes. The principal products transported include petrochemicals, black oil, refined petroleum products and agricultural chemicals.

Diesel Engine Services — Provides after-market services for medium-speed and high-speed diesel engines, reduction gears and ancillary products for marine and power generation applications, distributes and services high-speed diesel engines, transmissions and pumps, and manufactures and remanufactures oilfield service equipment, including pressure pumping units, for the land-based oilfield service and oil and gas operator and producer markets.

The Company’s two reportable business segments are managed separately based on fundamental differences in their operations. The Company’s accounting policies for the business segments are the same as those described in Note 1, Summary of Significant Accounting Policies. The Company evaluates the performance of its segments based on the contributions to operating income of the respective segments, and before income taxes, interest, gains or losses on disposition of assets, other nonoperating income, noncontrolling interests, accounting changes, and nonrecurring items. Intersegment revenues, based on market-based pricing, of the diesel engine services segment from the marine transportation segment of $24,672,000, $26,203,000 and $25,769,000 in 2016, 2015 and 2014, respectively, as well as the related intersegment profit of $2,467,000, $2,620,000 and $2,577,000 in 2016, 2015 and 2014, respectively, have been eliminated from the tables below.

The following table sets forth by reportable segment the revenues, profit or loss, total assets, depreciation and amortization, and capital expenditures attributable to the principal activities of the Company for the years ended December 31, 2016, 2015 and 2014 (in thousands):

	2016			2015			2014
Revenues:
Marine transportation	$	1,471,893		$	1,663,090		$	1,770,684
Diesel engine services		298,780			484,442			795,634
	$	1,770,673		$	2,147,532		$	2,566,318
Segment profit (loss):
Marine transportation	$	257,102		$	374,842		$	429,864
Diesel engine services		3,186			18,921			60,063
Other		(32,542	)		(32,051	)		(35,537	)
	$	227,746		$	361,712		$	454,390
Total assets:
Marine transportation	$	3,622,348		$	3,451,553		$	3,317,696
Diesel engine services		628,290			637,549			736,129
Other		52,861			63,179			83,789
	$	4,303,499		$	4,152,281		$	4,137,614
Depreciation and amortization:
Marine transportation	$	184,291		$	175,798		$	154,019
Diesel engine services		12,833			12,498			11,463
Other		3,793			3,944			3,830
	$	200,917		$	192,240		$	169,312
Capital expenditures:
Marine transportation	$	217,423		$	311,862		$	340,315
Diesel engine services		5,915			28,907			7,486
Other		7,728			4,706			7,343
	$	231,066		$	345,475		$	355,144

The following table presents the details of “Other” segment profit (loss) for the years ended December 31, 2016, 2015 and 2014 (in thousands):

	2016			2015			2014
General corporate expenses	$	(14,966	)	$	(14,773	)	$	(14,896	)
Interest expense		(17,690	)		(18,738	)		(21,461	)
Gain (loss) on disposition of assets		(127	)		1,672			781
Other income (expense)		241			(212	)		39
	$	(32,542	)	$	(32,051	)	$	(35,537	)

The following table presents the details of “Other” total assets as of December 31, 2016, 2015 and 2014 (in thousands):

	2016		2015		2014
General corporate assets	$	50,239	$	61,089	$	81,250
Investment in affiliates		2,622		2,090		2,539
	$	52,861	$	63,179	$	83,789

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2016
Related Party Transactions [Abstract]
Related Party Transactions	(15) Related Party Transactions Richard J. Alario, a current director of the Company, was Chief Executive Officer of Key Energy Services, Inc. (“Key Energy”) until his retirement on March 1, 2016. Key Energy paid the Company $80,000 during the period of January 1, 2016 to March 1, 2016, $572,000 in 2015 and $1,232,000 in 2014 for oilfield service equipment and for parts and service. Such sales and service were in the ordinary course of business of the Company. The Company is a 50% owner of The Hollywood Camp, L.L.C. (“The Hollywood Camp”), a company that owns and operates a hunting and fishing facility used by the Company primarily for customer entertainment. The Hollywood Camp allocates lease and lodging expenses to its members based on their usage of the facilities. Key Energy paid The Hollywood Camp $221,000 during the period of January 1, 2016 to March 1, 2016, $1,236,000 in 2015 and $1,634,000 in 2014 for use of the facility. The Company paid The Hollywood Camp $3,143,000 in 2016, $2,830,000 in 2015 and $2,303,000 in 2014 for its share of facility expenses. The husband of Amy D. Husted, Vice President and General Counsel of the Company, is a partner in the law firm of Strasburger & Price, LLP. The Company paid the law firm $779,000 in 2016, $596,000 in 2015 and $1,184,000 in 2014 for legal services in connection with matters in the ordinary course of business of the Company. The Company is a 50% owner of Bolivar Terminal Co., Inc. (“Bolivar”), a company that provides barge fleeting services (temporary barge storage facilities) in the Houston, Texas area. The Company paid Bolivar $1,314,000 in 2016, $895,000 in 2015 and $561,000 in 2014 for barge fleeting services. Such services were in the ordinary course of business of the Company.

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation. The consolidated financial statements include the accounts of Kirby Corporation and all majority-owned subsidiaries (“the Company”). All investments in which the Company owns 20% to 50% and exercises significant influence over operating and financial policies are accounted for using the equity method. All material intercompany accounts and transactions have been eliminated in consolidation. Certain reclassifications have been made to reflect the current presentation of financial information.
Cash Equivalents	Cash Equivalents. Cash equivalents consist of all short-term, highly liquid investments with maturities of three months or less at date of purchase.
Accounts Receivable	Accounts Receivable. In the normal course of business, the Company extends credit to its customers. The Company regularly reviews the accounts and makes adequate provisions for probable uncollectible balances. It is the Company’s opinion that the accounts have no impairment, other than that for which provisions have been made. Included in accounts receivable as of December 31, 2016 and 2015 were $84,453,000 and $90,166,000, respectively, of accruals for revenues earned which have not been invoiced as of the end of each year. The Company’s marine transportation and diesel engine services operations are subject to hazards associated with such businesses. The Company maintains insurance coverage against these hazards with insurance companies. Included in accounts receivable as of December 31, 2016 and 2015 were $88,182,000 and $77,684,000, respectively, of receivables from insurance companies to cover claims in excess of the Company’s deductible.
Concentrations of Credit Risk	Concentrations of Credit Risk. Financial instruments which potentially subject the Company to concentrations of credit risk are primarily trade accounts receivables. The Company’s marine transportation customers include the major oil refining and petrochemical companies. The diesel engine services customers are oil and gas service companies, marine transportation companies, commercial fishing companies, power generation companies, and the United States government. The Company regularly reviews its accounts and estimates the amount of uncollectible receivables each period and establishes an allowance for uncollectible amounts. The amount of the allowance is based on the age of unpaid amounts, information about the current financial strength of customers, and other relevant information. Estimates of uncollectible amounts are revised each period, and changes are recorded in the period they become known.
Fair Value of Financial Instruments	Fair Value of Financial Instruments. Cash, accounts receivable, accounts payable and accrued liabilities have carrying values that approximate fair value due to the short-term maturity of these financial instruments. The fair value of the Company’s debt instruments is more fully described in Note 5, Long-Term Debt.
Property, Maintenance and Repairs	Property, Maintenance and Repairs. Property is recorded at cost. Improvements and betterments are capitalized as incurred. Depreciation is recorded on the straight-line method over the estimated useful lives of the individual assets as follows: marine transportation equipment, 5-40 years; buildings, 10-40 years; other equipment, 2-10 years; and leasehold improvements, term of lease. When property items are retired, sold or otherwise disposed of, the related cost and accumulated depreciation are removed from the accounts with any gain or loss on the disposition included in the statement of earnings. Maintenance and repairs on vessels built for use on the inland waterways are charged to operating expense as incurred and includes the costs incurred in United States Coast Guard (“USCG”) inspections unless the shipyard extends the life or improves the operating capacity of the vessel which results in the costs being capitalized.
Drydocking on Ocean-Going Vessels	Drydocking on Ocean-Going Vessels. The Company’s ocean-going vessels are subject to regulatory drydocking requirements after certain periods of time to be inspected, have planned major maintenance performed and be recertified by the American Bureau of Shipping (“ABS”). These recertifications generally occur twice in a five year period. The Company defers the drydocking expenditures incurred on its ocean-going vessels due to regulatory marine inspections by the ABS and amortizes the costs of the shipyard over the period between drydockings, generally 30 or 60 months, depending on the type of major maintenance performed. Drydocking expenditures that extend the life or improve the operating capability of the vessel result in the costs being capitalized. The Company recognized amortization of major maintenance costs of $19,869,000, $22,126,000 and $16,409,000 for the years ended December 31, 2016, 2015 and 2014, respectively, in costs of sales and operating expenses. Routine repairs and maintenance on ocean-going vessels are expensed as incurred. Interest is capitalized on the construction of new ocean-going vessels. Interest expense excludes capitalized interest of $2,974,000, $3,026,000 and $639,000 for the years ending December 31, 2016, 2015 and 2014, respectively.
Environmental Liabilities	Environmental Liabilities. The Company expenses costs related to environmental events as they are incurred or when a loss is considered probable and estimable.
Goodwill	Goodwill. The excess of the purchase price over the fair value of identifiable net assets acquired in transactions accounted for as a purchase is included in goodwill. The Company conducted its annual goodwill impairment test at November 30, 2016 and 2015. For 2016 and 2015, the Company noted no impairment of goodwill. The Company will continue to conduct goodwill impairment tests as of November 30 of subsequent years, or whenever events or circumstances indicate that interim impairment testing is necessary. The amount of goodwill impairment, if any, is typically measured based on projected discounted future operating cash flows using an appropriate discount rate. The gross carrying value of goodwill at December 31, 2016 and 2015 was $615,598,000 and $604,185,000, respectively, and accumulated amortization at December 31, 2016 and 2015 was $15,566,000. Accumulated impairment losses were $1,901,000 at December 31, 2016 and 2015. Net goodwill for the marine transportation segment was $382,227,000 and $381,243,000 at December 31, 2016 and 2015, respectively. The increase in net goodwill for the marine transportation segment was due to the purchase of an inland tank barge fleet in 2016 which is more fully described in Note 2, Acquisitions. Net goodwill for the diesel engine services segment was $215,904,000 and $205,475,000 at December 31, 2016 and 2015, respectively. The increase in net goodwill for the diesel engine services segment was mainly due to the acquisition of an engine supply and repair business in 2016, also more fully described in Note 2, Acquisitions.
Revenue Recognition	Revenue Recognition. The majority of marine transportation revenue is derived from term contracts, ranging from one to five years, some of which have renewal options, and the remainder is from spot market movements. The majority of the term contracts are for terms of one year. The Company is a provider of marine transportation services for its customers and, in almost all cases, does not assume ownership of the products it transports. A term contract is an agreement with a specific customer to transport cargo from a designated origin to a designated destination at a set rate or at a daily rate. The rate may or may not escalate during the term of the contract, however, the base rate generally remains constant and contracts often include escalation provisions to recover changes in specific costs such as fuel. A spot contract is an agreement with a customer to move cargo from a specific origin to a designated destination for a rate negotiated at the time the cargo movement takes place. Spot contract rates are at the current “market” rate, including fuel, and are subject to market volatility. The Company uses a voyage accounting method of revenue recognition for its marine transportation revenues which allocates voyage revenue based on the percent of the voyage completed during the period. There is no difference in the recognition of revenue between a term contract and a spot contract. Diesel engine service products and services are generally sold based upon purchase orders or preferential service agreements with the customer that include fixed or determinable prices and that do not include right of return or significant post-delivery performance obligations. Diesel engine parts sales are recognized when title passes upon shipment to customers or when customer-specific acceptance requirements are met. Service revenue is recognized as the service is provided. Diesel manufacturing and assembly projects revenue is reported on the percentage of completion method of accounting using measurements of progress towards completion appropriate for the work performed.
Stock-Based Compensation	Stock-Based Compensation. The Company has share-based compensation plans covering selected officers and other key employees as well as the Company’s Board of Directors. Stock-based grants made under the Company’s stock plans are recorded at fair value on the date of the grant and the cost is recognized ratably over the vesting period of the stock option or restricted stock. Stock option grants are valued at the date of grant as calculated under the Black-Scholes option pricing model. The Company’s stock-based compensation plans are more fully described in Note 8, Stock Award Plans.
Taxes on Income	Taxes on Income. The Company follows the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax basis and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date.
Accrued Insurance	Accrued Insurance. Accrued insurance liabilities include estimates based on individual incurred claims outstanding and an estimated amount for losses incurred but not reported (“IBNR”) or fully developed based on past experience. Insurance premiums, IBNR losses and incurred claim losses, in excess of the Company’s deductible for 2016, 2015 and 2014 were $23,085,000, $23,737,000 and $25,416,000, respectively.
Noncontrolling Interests	Noncontrolling Interests. The Company has a majority interest in and is the general partner in several affiliated entities. In situations where losses applicable to the minority interest in the affiliated entities exceed the limited partners’ equity capital, such excess and any further loss attributable to the minority interest is charged against the Company’s interest in the affiliated entities. If future earnings materialize in the respective affiliated entities, the Company’s interest would be credited to the extent of any losses previously absorbed.
Treasury Stock	Treasury Stock. The Company follows the average cost method of accounting for treasury stock transactions.
Impairment of Long-Lived Assets and for Long-Lived Assets to Be Disposed Of	Impairment of Long-Lived Assets and for Long-Lived Assets to Be Disposed Of. The Company reviews long-lived assets and certain identifiable intangibles for impairment by vessel class whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability on marine transportation assets is assessed based on vessel classes, not on individual assets, because identifiable cash flows for individual marine transportation assets are not available. Projecting customer contract volumes allows estimation of future cash flows by projecting pricing and utilization by vessel class but it is not practical to project which individual marine transportation asset will be utilized for any given contract. Because customers do not specify which particular vessel is used, prices are quoted based on vessel classes not individual assets. Nominations of vessels for specific jobs are determined on a day by day basis and are a function of the equipment class required and the geographic position of vessels within that class at that particular time as vessels within a class are interchangeable and provide the same service. The Company’s vessels are mobile assets and equipped to operate in geographic regions throughout the United States and the Company has in the past and expects to continue to move vessels from one region to another when it is necessary due to changing markets and it is economical to do so. Barge vessel classes are based on similar capacities, hull type, and type of product and towing vessels are based on similar hull type and horsepower. Recoverability of the vessel classes is measured by a comparison of the carrying amount of the assets to future net cash flows expected to be generated by the assets. If such assets are considered to be impaired, the impairment to be recognized is measured by the amount by which the carrying amount of the assets exceeds the fair value of the assets. Assets to be disposed of are reported at the lower of the carrying amount or fair value less costs to sell.
Accounting Standards	Accounting Standards In August 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments” (“ASU 2016-15”) to create consistency in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows. ASU 2016-15 is effective for annual and interim periods beginning after December 15, 2017. Early adoption is permitted. The Company is currently evaluating the impact that the adoption of this standard will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”) which simplifies several aspects of the accounting for share-based payment transactions, including income tax consequences, forfeitures, minimum statutory tax withholding requirements, classification as either equity or liabilities, and classification on the statement of cash flows. ASU 2016-09 is effective for annual and interim periods beginning after December 15, 2016. The Company will adopt the provisions of ASU 2016-09 on January 1, 2017 and the Company does not expect the adoption of ASU 2016-09 to have a material impact on its consolidated financial statements. However, the adoption will result in some income statement volatility in 2017 and beyond due to the requirement that the tax effects of exercised or vested equity awards be recognized as discrete items in income tax expense or benefit in the income statement in the reporting period in which they occur. In February 2016, the FASB issued ASU No. 2016-02, “Leases (Topic 842)” (“ASU 2016-02”) to increase transparency and comparability among organizations by requiring recognition of lease assets and lease liabilities on the balance sheet and disclosure of key information about leasing arrangements. ASU 2016-02 is effective for annual and interim periods beginning after December 15, 2018, with early adoption permitted. A modified retrospective approach is required. The Company has formed a project team to evaluate the impact that the adoption of this standard will have on its consolidated financial statements and disclosures. The project team has completed training on the new standard and has started lease review and documentation, but the Company has not yet determined the effect of ASU 2016-02 on its ongoing financial reporting. In November 2015, the FASB issued ASU 2015-17, “Balance Sheet Classification of Deferred Taxes” (“ASU 2015-17”) which requires that deferred tax liabilities and assets be classified as noncurrent on the balance sheet. The current requirement that deferred tax liabilities and assets of a tax-paying component of an entity be offset and presented as a single amount is not affected by this guidance. ASU 2015-17 is effective for annual and interim periods beginning after December 15, 2016 but early application is permitted and the guidance may be applied either prospectively to all deferred tax liabilities and assets or retrospectively to all periods presented. The Company will adopt the provisions of ASU 2015-17 on January 1, 2017 and the Company does not expect the adoption of ASU 2015-17 to have a material impact on its consolidated financial statements. In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory” (“ASU 2015-11”) which applies to inventory that is measured using first-in, first-out (“FIFO”) or average cost. Under the guidance, an entity should measure inventory that is within the scope of this update at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal and transportation. ASU 2015-11 is effective for annual and interim periods beginning after December 15, 2016, and should be applied prospectively with early adoption permitted at the beginning of an interim period or annual reporting period. The Company will adopt the provisions of ASU 2015-11 on January 1, 2017 and the Company does not expect the adoption of ASU 2015-11 to have a material impact on its consolidated financial statements. In April 2015, the FASB issued ASU 2015-03, “Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”). ASU 2015-03 requires debt issuance costs to be presented in the balance sheet as a direct deduction from the associated debt liability. Effective January 1, 2016, the Company adopted the provisions of ASU 2015-03 and prior period amounts have been reclassified to conform to the current period presentation. The December 31, 2015 net debt issuance costs of $3,985,000 have been reclassified in the consolidated balance sheet from other assets to long-term debt, less current portion. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern” (“ASU 2014-15”), which provides guidance about management's responsibility in evaluating whether there is substantial doubt relating to an entity’s ability to continue as a going concern and to provide related footnote disclosures as applicable. Adoption of ASU 2014-15 as of December 31, 2016 did not impact the Company’s financial statements or disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 requires an entity to recognize the amount of revenue to which it expects to be entitled for the transfer of promised goods or services to customers. ASU 2014-09 will replace most existing revenue recognition guidance in United States Generally Accepted Accounting Principles when it becomes effective. In July 2015, the FASB voted to delay the effective date of ASU 2014-09 by one year, making it effective for fiscal years, and interim periods within those years, beginning after December 15, 2017, with early adoption permitted as of the original effective date. ASU 2014-09 permits the use of either the retrospective, modified retrospective or prospective with a cumulative catch-up approach. The Company has formed a project team to evaluate the standard and determine the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. The project team has completed training on the new standard and has started contract review and documentation. The Company has not yet selected a transition method nor has it determined the effect of ASU 2014-09 on its ongoing financial reporting.

Inventories (Tables)

12 Months Ended

Dec. 31, 2016

Inventories [Abstract]

Schedule of Details of Inventories

The following table presents the details of inventories as of December 31, 2016 and 2015 (in thousands):

	December 31, 2016		December 31, 2015
Finished goods	$	178,740	$	163,501
Work in process		6,662		21,010
	$	185,402	$	184,511

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2016

Long-Term Debt [Abstract]

Schedule of Long-Term Debt

Long-term debt at December 31, 2016 and 2015 consisted of the following (in thousands):

	2016			2015
Long-term debt, including current portion:
$550,000,000 revolving credit facility due April 30, 2020	$	225,986		$	278,834
$150,000,000 senior notes Series A due February 27, 2020		150,000			150,000
$350,000,000 senior notes Series B due February 27, 2023		350,000			350,000
$10,000,000 credit line due June 30, 2017		—			—
	$	725,986		$	778,834
Unamortized debt issuance costs		(3,184	)		(3,985	)
	$	722,802		$	774,849

Schedule of Aggregate Payments due on the Long-Term Debt

The aggregate payments due on the long-term debt in each of the next five years were as follows (in thousands):

2017	$	—
2018		—
2019		—
2020		375,986
2021		—
Thereafter		350,000
	$	725,986

Taxes on Income (Tables)

12 Months Ended

Dec. 31, 2016

Taxes on Income [Abstract]

Earnings Before Taxes

Earnings before taxes on income and details of the provision for taxes on income for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	2016		2015		2014
Earnings before taxes on income — United States	$	227,746	$	361,712	$	454,390

Provision for taxes on income:
Federal:
Current	$	28,919	$	64,707	$	81,953
Deferred		49,685		59,582		72,920
State and local		6,338		9,453		14,909
	$	84,942	$	133,742	$	169,782

Schedule of Effective Income Tax Rate Reconciliation

The Company’s provision for taxes on income varied from the statutory federal income tax rate for the years ended December 31, 2016, 2015 and 2014 due to the following:

	2016			2015			2014
United States income tax statutory rate		35.0	%		35.0	%		35.0	%
State and local taxes, net of federal benefit		1.8			1.7			2.2
Other – net		.5			.3			.2
		37.3	%		37.0	%		37.4	%

Schedule of Deferred Tax Assets and Liabilities

	2016			2015
Current deferred tax assets:
Compensated absences	$	739		$	829
Allowance for doubtful accounts		2,534			3,288
Insurance accruals		6,218			4,234
Other		4,113			3,372
	$	13,604		$	11,723

Non-current deferred tax assets and liabilities:
Deferred tax assets:
Postretirement health care benefits	$	2,234		$	2,501
Insurance accruals		2,910			3,410
Deferred compensation		11,124			10,534
Unrealized loss on defined benefit plans		28,832			25,245
Operating loss carryforwards		7,846			5,188
Other		21,622			20,702
Valuation allowances		(7,417)			(4,716)
		67,151			62,864

Deferred tax liabilities:
Property		(654,751	)		(604,737	)
Deferred state taxes		(54,812	)		(53,542	)
Pension benefits		(2,799	)		(8,471	)
Goodwill and other intangibles		(51,551	)		(44,185	)
Other		(22,295	)		(21,737	)
		(786,208	)		(732,672	)
	$	(719,057	)	$	(669,808	)

Reconciliation of Liability for Unrecognized Tax Benefits

A reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits for the years ended December 31, 2016, 2015 and 2014, is as follows (in thousands):

	2016			2015			2014
Balance at beginning of year	$	1,958		$	1,171		$	949
Additions based on tax positions related to the current year		187			339			470
Additions for tax positions of prior years		867			785			39
Reductions for tax positions of prior years		(441	)		(337	)		(287	)
Settlements		(552	)		—			—
Balance at end of year	$	2,019		$	1,958		$	1,171

Leases (Tables)

12 Months Ended

Dec. 31, 2016

Leases [Abstract]

Schedule of Rent Expense

Total rental expense for the years ended December 31, 2016, 2015 and 2014 was as follows (in thousands):

	2016		2015		2014
Rental expense:
Marine equipment — barges	$	13,791	$	14,092	$	19,780
Marine equipment — towing vessels		137,609		143,067		136,331
Other buildings and equipment		11,182		9,383		9,146
Rental expense	$	162,582	$	166,542	$	165,257

Schedule of Future Minimum Lease Payments under Operating Leases

Future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2016 were as follows (in thousands):

	Land, Buildings		Marine Equipment
	And Equipment		Barges		Towing Vessels		Total
2017	$	12,027	$	10,419	$	83,949	$	106,395
2018		11,049		8,718		20,532		40,299
2019		8,829		4,581		314		13,724
2020		7,508		3,813		—		11,321
2021		7,007		1,574		—		8,581
Thereafter		74,390		2,474		—		76,864
	$	120,810	$	31,579	$	104,795	$	257,184

Stock Award Plans (Tables)

12 Months Ended

Dec. 31, 2016

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Compensation Cost Breakdown in Statement of Earnings

	2016		2015		2014
Compensation cost	$	11,675	$	11,104	$	11,591
Income tax benefit	$	4,378	$	4,120	$	4,358

Summary of Stock Option Valuation Assumptions

The fair value of each stock option was determined using the Black-Scholes option pricing model. The key input variables used in valuing the stock options during the years ended December 31, 2016, 2015 and 2014 were as follows:

	2016			2015			2014
Dividend yield	None			None			None
Average risk-free interest rate		1.5	%		1.3	%		2.0	%
Stock price volatility		30	%		33	%		33	%
Estimated option term		Six years			Six years			Six years or seven years

Employee Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock Option Activity

The following is a summary of the stock option activity under the employee plan described above for the years ended December 31, 2016, 2015 and 2014:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2013		379,604		$	55.42
Granted		75,204		$	98.91
Exercised		(119,276	)	$	42.07
Canceled or expired		(12,576	)	$	68.89
Outstanding at December 31, 2014		322,956		$	69.95
Granted		114,894		$	74.99
Exercised		—		$	—
Canceled or expired		(7,418	)	$	86.28
Outstanding at December 31, 2015		430,432		$	71.01
Granted		186,706		$	53.50
Exercised		—		$	—
Canceled or expired		(16,017	)	$	80.17
Outstanding at December 31, 2016		601,121		$	65.33

Summary of Outstanding and Exercisable Stock Options

The following table summarizes information about the Company’s outstanding and exercisable stock options under the employee plan at December 31, 2016:

		Options Outstanding								Options Exercisable
Range of Exercise Prices		Number Outstanding		Weighted Average Remaining Contractual Life in Years		Weighted Average Exercise Price		Aggregated Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregated Intrinsic Value
$	31.35 – $36.35		16,910		0.1	$	32.82				16,910	$	32.82
$	46.74 – $51.23		212,335		4.8	$	50.03				56,629	$	46.74
$	64.89 – $74.99		302,735		4.1	$	70.29				202,309	$	69.51
$	93.64 – $96.85		33,987		4.1	$	94.31				22,658	$	94.31
$	101.46 – $104.37		35,154		4.2	$	102.60				23,436	$	102.60
$	31.35 – $104.37		601,121		4.2	$	65.33	$	4,175,000		321,942	$	67.73	$	1,747,000

Summary of Restricted Stock Award Activity

The following is a summary of the restricted stock award activity under the employee plan described above for the years ended December 31, 2016, 2015 and 2014:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2013		399,278		$	54.92
Granted		97,706		$	97.46
Vested		(141,870	)	$	45.64
Forfeited		(33,661	)	$	63.56
Nonvested balance at December 31, 2014		321,453		$	71.04
Granted		122,740		$	75.04
Vested		(113,958	)	$	60.73
Forfeited		(18,508	)	$	82.00
Nonvested balance at December 31, 2015		311,727		$	75.73
Granted		190,610		$	53.56
Vested		(105,109	)	$	69.93
Forfeited		(19,573	)	$	76.06
Nonvested balance at December 31, 2016		377,655		$	66.14

Director Plan [Member]

Share-based Compensation Arrangement by Share-based Payment Award [Line Items]

Summary of Stock Option Activity

The following is a summary of the stock option activity under the director plan described above for the years ended December 31, 2016, 2015, and 2014:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2013		320,322		$	50.64
Granted		42,000		$	99.52
Exercised		(63,988	)	$	39.08
Outstanding at December 31, 2014		298,334		$	60.01
Exercised		(77,905	)	$	47.65
Outstanding at December 31, 2015		220,429		$	64.37
Exercised		(9,000	)	$	35.72
Canceled or expired		(6,000	)	$	99.52
Outstanding at December 31, 2016		205,429		$	64.60

Summary of Outstanding and Exercisable Stock Options

The following table summarizes information about the Company’s outstanding and exercisable stock options under the director plan at December 31, 2016:

		Options Outstanding								Options Exercisable
Range of Exercise Prices		Number Outstanding		Weighted Average Remaining Contractual Life in Years		Weighted Average Exercise Price		Aggregate Intrinsic Value		Number Exercisable		Weighted Average Exercise Price		Aggregate Intrinsic Value
$	29.60 – $36.82		21,000		0.9	$	32.69				21,000	$	32.69
$	41.24 – $56.45		71,276		2.7	$	52.34				71,276	$	52.34
$	61.89 – $62.48		41,153		4.8	$	62.34				41,153	$	62.34
$	75.17 – $99.52		72,000		5.7	$	87.35				72,000	$	87.35
$	29.60 – $99.52		205,429		4.0	$	64.60	$	1,891,000		205,429	$	64.60	$	1,891,000

Summary of Restricted Stock Award Activity

The following is a summary of the restricted stock award activity under the director plan described above for the years ended December 31, 2016, 2015 and 2014:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2013		384		$	75.65
Granted		8,160		$	99.52
Vested		(8,252	)	$	98.41
Nonvested balance at December 31, 2014		292		$	99.52
Granted		20,350		$	78.52
Vested		(18,851	)	$	79.77
Nonvested balance at December 31, 2015		1,791		$	68.73
Granted		23,074		$	64.89
Vested		(24,518	)	$	65.17
Nonvested balance at December 31, 2016		347		$	64.89

Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2016

Defined Benefit Plan Disclosure [Line Items]

Summary of Asset Allocation

As of December 31, 2016 and 2015, these assets were allocated among asset categories as follows:

Asset Category	2016			2015			Current Minimum, Target and Maximum Allocation Policy
U.S. equity securities		51	%		50	%		30% — 50%— 70	%
International equity securities		19	%		18	%		0% — 20%— 30	%
Debt securities		30	%		28	%		15% — 30%— 55	%
Cash and cash equivalents		—	%		4	%		0% — 0%— 5	%
		100	%		100	%

Schedule of Change in Benefit Obligation

The following table presents the change in benefit obligation and plan assets for the Company’s defined benefit plans and postretirement benefit plan (in thousands):

													Other Postretirement Benefits
	Pension Benefits												Postretirement
	Pension Plan						SERP						Welfare Plan
	2016			2015			2016			2015			2016			2015
Change in benefit obligation
Benefit obligation at beginning of year	$	297,325		$	315,075		$	1,526		$	1,637		$	891		$	1,264
Service cost		13,402			14,683			—			—			—			—
Interest cost		14,123			13,302			65			64			29			36
Actuarial loss (gain)		19,120			(39,474	)		12			(30	)		(198	)		(321	)
Gross benefits paid		(6,794	)		(6,261	)		(146	)		(145	)		(47	)		(88	)
Benefit obligation at end of year	$	337,176		$	297,325		$	1,457		$	1,526		$	675		$	891

Accumulated benefit obligation at end of year	$	272,591		$	238,775		$	1,457		$	1,526		$	675		$	891

Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost

Weighted-average assumption used to determine benefit obligation at end of year
Discount rate		4.2	%		4.5	%	4.2	%	4.5	%	4.2	%	4.5	%
Rate of compensation increase	Service- based table			Service- based table			—		—		—		—
Health care cost trend rate
Initial rate		—			—		—		—		7.0	%	6.5	%
Ultimate rate		—			—		—		—		5.0	%	5.0	%
Years to ultimate		—			—		—		—		2021		2019

Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rate

Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation
Increase	$	—	$	—	$	—	$	—	$	74		$	107
Decrease		—		—		—		—		(64	)		(93	)

Summary of Change in Plan Assets

Change in plan assets
Fair value of plan assets at beginning of year	$	243,588		$	242,275		$	—		$	—		$	—		$	—
Actual return on plan assets		20,723			(2,426	)		—			—			—			—
Employer contribution		—			10,000			146			145			47			88
Gross benefits paid		(6,794	)		(6,261	)		(146	)		(145	)		(47	)		(88	)
Fair value of plan assets at end of year	$	257,517		$	243,588		$	—		$	—		$	—		$	—

Summary of Funded Status at End of Year

													Other Postretirement Benefits
	Pension Benefits												Postretirement
	Pension Plan						SERP						Welfare Plan
	2016			2015			2016			2015			2016			2015
Funded status at end of year
Fair value of plan assets	$	257,517		$	243,588		$	—		$	—		$	—		$	—
Benefit obligations		(337,176	)		(297,325	)		(1,457	)		(1,526	)		(675	)		(891	)
Funded status and amount recognized at end of year	$	(79,659	)	$	(53,737	)	$	(1,457	)	$	(1,526	)	$	(675	)	$	(891	)

Amounts Recognized in the Consolidated Balance Sheets

Amounts recognized in the consolidated balance sheets
Noncurrent asset	$	—		$	—		$	—		$	—		$	—		$	—
Current liability		—			—			(150	)		(149	)		(56	)		(68	)
Long-term liability		(79,659	)		(53,737	)		(1,307	)		(1,377	)		(619	)		(823	)

Amounts Recognized in Accumulated Other Comprehensive Income

Amounts recognized in accumulated other comprehensive income
Net actuarial loss (gain)	$	87,658	$	77,940	$	494	$	508	$	(5,773	)	$	(6,319	)
Prior service cost (credit)		—		—		—		—		—			—
Accumulated other compensation income	$	87,658	$	77,940	$	494	$	508	$	(5,773	)	$	(6,319	)

Projected Benefit Obligation in Excess of Plan Assets

	Pension Benefits
	Pension Plan				SERP
	2016		2015		2016		2015
Projected benefit obligation in excess of plan assets
Projected benefit obligation at end of year	$	337,176	$	297,325	$	1,457	$	1,526
Fair value of plan assets at end of year		257,517		243,588		—		—

Accumulated Benefit Obligation in Excess of Plan Assets

	Pension Benefits
	Pension Plan				SERP
	2016		2015		2016		2015
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation at end of year	$	337,176	$	—	$	1,457	$	1,526
Accumulated benefit obligation at end of year		272,591		—		1,457		1,526
Fair value of plan assets at end of year		257,517		—		—		—

Schedule of Employer Contribution

The following tables presents the expected cash flows for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2016 and 2015 (in thousands):

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2016		2015		2016		2015		2016		2015
Expected employer contributions
First year	$	—	$	—	$	153	$	152	$	50	$	70

Expected Benefit Payments

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2016		2015		2016		2015		2016		2015
Expected benefit payments (gross)
Year one	$	8,032	$	7,678	$	153	$	152	$	58	$	81
Year two		8,835		8,298		157		157		58		86
Year three		9,646		9,013		155		154		58		86
Year four		10,400		9,748		151		152		58		86
Year five		11,201		10,415		148		149		57		85
Next five years		70,419		63,860		514		608		199		341

Summary of Expected Federal Subsidy

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2016		2015		2016		2015		2016			2015
Expected federal subsidy
Year one	$	—	$	—	$	—	$	—	$	(7	)	$	(11	)
Year two		—		—		—		—		(7	)		(11	)
Year three		—		—		—		—		(7	)		(11	)
Year four		—		—		—		—		(7	)		(12	)
Year five		—		—		—		—		(7	)		(12	)
Next five years		—		—		—		—		(33	)		(55	)

Pension Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Components of Net Periodic Benefit Cost

	Pension Benefits
	Pension Plan									SERP
	2016			2015			2014			2016			2015			2014
Components of net periodic benefit cost
Service cost	$	13,402		$	14,683		$	10,645		$	—		$	—		$	—
Interest cost		14,123			13,302			12,839			65			64			73
Expected return on plan assets		(16,805	)		(17,921	)		(18,858	)		—			—			—
Amortization:
Actuarial loss		5,484			7,728			701			26			28			16
Prior service credit		—			—			—			—			—			—
Net periodic benefit cost		16,204			17,792			5,327			91			92			89

Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		15,203			(19,127	)		72,737			12			(30	)		180
Recognition of actuarial loss		(5,484	)		(7,728	)		(701	)		(26	)		(28	)		(16	)
Recognition of prior service credit		—			—			—			—			—			—
Total recognized in other comprehensive income		9,719			(26,855	)		72,036			(14	)		(58	)		164

Total recognized in net periodic benefit cost and other comprehensive income	$	25,923		$	(9,063	)	$	77,363		$	77		$	34		$	253

Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost

Weighted average assumptions used to determine net periodic benefit cost
Discount rate		4.5	%	4.1	%	5.0	%	4.5	%	4.1	%	5.0	%
Expected long-term rate of return on plan assets		7.0	%	7.5	%	7.5	%	—		—		—
Rate of compensation increase	Service- based table			4.25	%	4.25	%	—		—		—

Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2017 are as follows (in thousands):

	Pension Benefits
	Pension Plan		SERP
Actuarial loss	$	5,477	$	28
Prior service credit		—		—
	$	5,477	$	28

Other Postretirement Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Components of Net Periodic Benefit Cost

	Other Postretirement Benefits
	Postretirement Welfare Plan
	2016			2015			2014
Components of net periodic benefit cost
Service cost	$	—		$	—		$	—
Interest cost		29			36			110
Amortization:
Actuarial gain		(747	)		(793	)		(649	)
Prior service cost		—			—			—
Net periodic benefit cost		(718	)		(757	)		(539	)

Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial gain		(198	)		(322	)		(1,065	)
Recognition of actuarial gain		747			793			649
Recognition of prior service cost		—			—			—
Adjustment for actual Medicare Part D reimbursement		(3	)		(3	)		(8	)
Total recognized in other comprehensive income		546			468			(424	)

Total recognized in net periodic benefit cost and other comprehensive income	$	(172	)	$	(289	)	$	(963	)

Weighted-Average Assumption Used to Determine Benefit Obligation and Net Periodic Benefit Cost

Weighted average assumptions used to determine net periodic benefit cost
Discount rate	4.5	%	4.1	%	5.0	%
Health care cost trend rate:
Initial rate	6.5	%	7.0	%	7.0	%
Ultimate rate	5.0	%	5.0	%	5.0	%
Years to ultimate	2019		2019		2018

Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rate

Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost
Increase	$	4		$	5		$	7
Decrease		(3	)		(4	)		(6	)

Estimated Amounts that will be Amortized from Accumulated Other Comprehensive Income into Net Periodic Benefit Cost

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2017 are as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
Actuarial gain	$	(668	)
Prior service cost		—
	$	(668	)

Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2016

Other Comprehensive Income [Abstract]

Schedule of Changes in Other Comprehensive income

The Company’s changes in other comprehensive income for the years ended December 31, 2016, 2015 and 2014 were as follows (in thousands):

	2016									2015							2014
	Gross Amount			Income Tax (Provision) Benefit			Net Amount			Gross Amount		Income Tax (Provision) Benefit			Net Amount		Gross Amount			Income Tax (Provision) Benefit			Net Amount
Pension and postretirement benefits (a):
Amortization of net actuarial loss	$	4,763		$	(1,825	)	$	2,938		$	6,963	$	(2,667	)	$	4,296	$	68		$	(26	)	$	42
Actuarial gains (losses)		(15,013	)		5,754			(9,259	)		19,482		(7,456	)		12,026		(71,843	)		27,507			(44,336	)

Foreign currency translation adjustments		—			—			—			29		—			29		(35	)		—			(35	)

Change in fair value of derivative instruments (b):
Unrealized gains (losses)		—			—			—			—		—			—		24			(9	)		15
Reclassified to net earnings		—			—			—			—		—			—		121			(51	)		70
Total	$	(10,250	)	$	3,929		$	(6,321	)	$	26,474	$	(10,123	)	$	16,351	$	(71,665	)	$	27,421		$	(44,244	)

(a)	Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 9 – Retirement Plans)

(b)	Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in costs of sales and operating expenses.

Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Earnings Per Share

The following table presents the components of basic and diluted earnings per share for the years ended December 31, 2016, 2015 and 2014 (in thousands, except per share amounts):

	2016			2015			2014
Net earnings attributable to Kirby	$	141,406		$	226,684		$	282,006
Undistributed earnings allocated to restricted shares		(999	)		(1,345	)		(1,643	)
Income available to Kirby common stockholders — basic		140,407			225,339			280,363
Undistributed earnings allocated to restricted shares		999			1,345			1,643
Undistributed earnings reallocated to restricted shares		(997	)		(1,343	)		(1,637	)
Income available to Kirby common stockholders — diluted	$	140,409		$	225,341		$	280,369

Shares outstanding:
Weighted average common stock issued and outstanding		53,834			55,056			57,006
Weighted average unvested restricted stock		(380	)		(327	)		(332	)
Weighted average common stock outstanding — basic		53,454			54,729			56,674
Dilutive effect of stock options		58			97			193
Weighted average common stock outstanding — diluted		53,512			54,826			56,867
Net earnings per share attributable to Kirby common stockholders:
Basic	$	2.63		$	4.12		$	4.95

Diluted	$	2.62		$	4.11		$	4.93

Quarterly Results (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2016

Quarterly Results (Unaudited) [Abstract]

Schedule of Quarterly Results

The unaudited quarterly results for the year ended December 31, 2016 were as follows (in thousands, except per share amounts):

	Three Months Ended
	March 31, 2016			June 30, 2016			September 30, 2016			December 31, 2016
Revenues	$	458,733		$	441,582		$	434,708		$	435,650
Costs and expenses		393,399			374,868			378,400			378,684
Gain (loss) on disposition of assets		67			94			(122	)		(166	)
Operating income		65,401			66,808			56,186			56,800
Other income (expense)		135			179			(120	)		47
Interest expense		(4,193	)		(4,513	)		(4,507	)		(4,477	)
Earnings before taxes on income		61,343			62,474			51,559			52,370
Provision for taxes on income		(22,859	)		(23,365	)		(19,206	)		(19,512	)
Net earnings		38,484			39,109			32,353			32,858
Less: Net earnings attributable to noncontrolling interests		(385	)		(167	)		(343	)		(503	)
Net earnings attributable to Kirby	$	38,099		$	38,942		$	32,010		$	32,355

Net earnings per share attributable to Kirby common stockholders:
Basic	$	0.71		$	0.72		$	0.59		$	0.60
Diluted	$	0.71		$	0.72		$	0.59		$	0.60

The unaudited quarterly results for the year ended December 31, 2015 were as follows (in thousands, except per share amounts):

	Three Months Ended
	March 31, 2015			June 30, 2015			September 30, 2015			December 31, 2015
Revenues	$	587,673		$	543,156		$	532,565		$	484,138
Costs and expenses		486,136			445,113			437,115			400,178
Gain (loss) on disposition of assets		1,555			91			(400	)		426
Operating income		103,092			98,134			95,050			84,386
Other income (expense)		60			(303	)		22			9
Interest expense		(5,250	)		(4,759	)		(4,449	)		(4,280	)
Earnings before taxes on income		97,902			93,072			90,623			80,115
Provision for taxes on income		(36,491	)		(34,696	)		(33,512	)		(29,043	)
Net earnings		61,411			58,376			57,111			51,072
Less: Net earnings attributable to noncontrolling interests		(333	)		(301	)		(268	)		(384	)
Net earnings attributable to Kirby	$	61,078		$	58,075		$	56,843		$	50,688

Net earnings per share attributable to Kirby common stockholders:
Basic	$	1.09		$	1.04		$	1.04		$	0.94
Diluted	$	1.09		$	1.04		$	1.04		$	0.94

Segment Data (Tables)

12 Months Ended

Dec. 31, 2016

Segment Data [Abstract]

Schedule of Segment Reporting Information, by Segment

	2016			2015			2014
Revenues:
Marine transportation	$	1,471,893		$	1,663,090		$	1,770,684
Diesel engine services		298,780			484,442			795,634
	$	1,770,673		$	2,147,532		$	2,566,318
Segment profit (loss):
Marine transportation	$	257,102		$	374,842		$	429,864
Diesel engine services		3,186			18,921			60,063
Other		(32,542	)		(32,051	)		(35,537	)
	$	227,746		$	361,712		$	454,390
Total assets:
Marine transportation	$	3,622,348		$	3,451,553		$	3,317,696
Diesel engine services		628,290			637,549			736,129
Other		52,861			63,179			83,789
	$	4,303,499		$	4,152,281		$	4,137,614
Depreciation and amortization:
Marine transportation	$	184,291		$	175,798		$	154,019
Diesel engine services		12,833			12,498			11,463
Other		3,793			3,944			3,830
	$	200,917		$	192,240		$	169,312
Capital expenditures:
Marine transportation	$	217,423		$	311,862		$	340,315
Diesel engine services		5,915			28,907			7,486
Other		7,728			4,706			7,343
	$	231,066		$	345,475		$	355,144

Schedule of Other Segment Reporting Information

The following table presents the details of “Other” segment profit (loss) for the years ended December 31, 2016, 2015 and 2014 (in thousands):

	2016			2015			2014
General corporate expenses	$	(14,966	)	$	(14,773	)	$	(14,896	)
Interest expense		(17,690	)		(18,738	)		(21,461	)
Gain (loss) on disposition of assets		(127	)		1,672			781
Other income (expense)		241			(212	)		39
	$	(32,542	)	$	(32,051	)	$	(35,537	)

The following table presents the details of “Other” total assets as of December 31, 2016, 2015 and 2014 (in thousands):

	2016		2015		2014
General corporate assets	$	50,239	$	61,089	$	81,250
Investment in affiliates		2,622		2,090		2,539
	$	52,861	$	63,179	$	83,789

Summary of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts Receivable [Abstract]
Accruals for revenues earned included in accounts receivable	$ 84,453,000	$ 90,166,000
Receivables from insurance companies to cover claims in excess included in accounts receivable	$ 88,182,000	77,684,000
Drydocking on Ocean-Going Vessels [Abstract]
Period in which recertification of ocean going vessels occur twice	5 years
Recognized amortization of major maintenance costs	$ 19,869,000	22,126,000	$ 16,409,000
Capitalized interest excluded from interest expense	2,974,000	3,026,000	639,000
Goodwill [Abstract]
Impairment of goodwill	0	0
Gross carrying value of goodwill	615,598,000	604,185,000
Accumulated amortization	15,566,000	15,566,000
Accumulated impairment losses	1,901,000	1,901,000
Net goodwill	598,131,000	586,718,000
Accrued Insurance [Abstract]
Accrued insurance liabilities	$ 23,085,000	23,737,000	$ 25,416,000
Minimum [Member]
Drydocking on Ocean-Going Vessels [Abstract]
Period of amortization of shipyard costs	30 months
Maximum [Member]
Drydocking on Ocean-Going Vessels [Abstract]
Period of amortization of shipyard costs	60 months
Marine Transportation Equipment [Member] \| Minimum [Member]
Property, Maintenance and Repairs [Abstract]
Estimated useful lives of the individual assets	5 years
Marine Transportation Equipment [Member] \| Maximum [Member]
Property, Maintenance and Repairs [Abstract]
Estimated useful lives of the individual assets	40 years
Buildings [Member] \| Minimum [Member]
Property, Maintenance and Repairs [Abstract]
Estimated useful lives of the individual assets	10 years
Buildings [Member] \| Maximum [Member]
Property, Maintenance and Repairs [Abstract]
Estimated useful lives of the individual assets	40 years
Other Equipment [Member] \| Minimum [Member]
Property, Maintenance and Repairs [Abstract]
Estimated useful lives of the individual assets	2 years
Other Equipment [Member] \| Maximum [Member]
Property, Maintenance and Repairs [Abstract]
Estimated useful lives of the individual assets	10 years
Marine Transportation Segment [Member]
Goodwill [Abstract]
Net goodwill	$ 382,227,000	381,243,000
Marine Transportation Segment [Member] \| Minimum [Member]
Revenue Recognition [Abstract]
Range of term contracts	1 year
Marine Transportation Segment [Member] \| Maximum [Member]
Revenue Recognition [Abstract]
Range of term contracts	3 years
Diesel Engine Services Segment [Member]
Goodwill [Abstract]
Net goodwill	$ 215,904,000	$ 205,475,000
ASU 2015-03 [Member]
Accounting Standards [Abstract]
Reclassification of debt issuance cost from other assets to long term debt, less current portion	$ 3,985,000

Acquisitions (Details)	Oct. 11, 2016 USD ($) State	Jun. 30, 2016 USD ($) Vessel bbl	Jun. 02, 2016 USD ($) Vessel	Apr. 15, 2016 USD ($) Vessel bbl	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Business Acquisition [Line Items]
Goodwill acquired					$ 598,131,000	$ 586,718,000
Valley Power Systems Northwest, Inc. [Member]
Business Acquisition [Line Items]
Purchase price	$ 11,440,000
Number of western states included in distributor agreement \| State	9
Goodwill acquired	$ 8,330,000
Intangible assets acquired	$ 2,070,000
Weighted average amortization period of intangibles	15 years
TD Equipment Finance, Inc. [Member]
Business Acquisition [Line Items]
Cash paid for acquisition		$ 13,682,000
TD Equipment Finance, Inc. [Member] \| Coastal Tank Barge [Member]
Business Acquisition [Line Items]
Number of maritime vessels \| Vessel		1
Tank barge barrel capacity \| bbl		80,000
Crosby Marine Transportation LLC [Member]
Business Acquisition [Line Items]
Cash paid for acquisition			$ 26,450,000
Crosby Marine Transportation LLC [Member] \| Coastal Tugboats [Member]
Business Acquisition [Line Items]
Number of maritime vessels \| Vessel			4
Average age of property			13 years
SEACOR Holdings Inc. [Member]
Business Acquisition [Line Items]
Purchase price				$ 89,181,000
Cash paid for acquisition				85,500,000
Ownership transferred, value				3,681,000
Goodwill acquired				985,000
Intangible assets acquired				$ 0
SEACOR Holdings Inc. [Member] \| Inland Tank Barges [Member]
Business Acquisition [Line Items]
Number of maritime vessels \| Vessel				27
Tank barge barrel capacity \| bbl				30,000
Average age of property				10 years
SEACOR Holdings Inc. [Member] \| Inland Towboats [Member]
Business Acquisition [Line Items]
Number of maritime vessels \| Vessel				14

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Details of inventories [Abstract]
Finished goods	$ 178,740	$ 163,501
Work in process	6,662	21,010
Inventory, Net, Total	$ 185,402	$ 184,511

Long-Term Debt, Schedule of Long-Term Debt (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term Debt	$ 725,986,000	$ 778,834,000
Unamortized debt issuance costs	(3,184,000)	(3,985,000)
Total	722,802,000	774,849,000
Revolving Credit Facility Due April 30, 2020 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 225,986,000	278,834,000
Credit facility, expiration date	Apr. 30, 2020
Long term debt, face amount	$ 550,000,000
Senior Notes Series A Due February 27, 2020 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 150,000,000	150,000,000
Credit facility, expiration date	Feb. 27, 2020
Long term debt, face amount	$ 150,000,000
Senior Notes Series B Due February 27, 2023 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 350,000,000	350,000,000
Credit facility, expiration date	Feb. 27, 2023
Long term debt, face amount	$ 350,000,000
Credit Line Due June 30, 2017 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 0	0
Credit facility, expiration date	Jun. 30, 2017
Long term debt, face amount	$ 10,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long term debt, face amount		$ 550,000,000

Long-Term Debt, Schedule of Aggregate Payments Due on The Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Long-Term Debt [Abstract]
2017	$ 0
2018	0
2019	0
2020	375,986
2021	0
Thereafter	350,000
Long-term Debt	$ 725,986	$ 778,834

Long-Term Debt (Details) - USD ($)	12 Months Ended
Long-Term Debt (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Line of credit, increase in aggregate commitments	$ 300,000,000
Senior Notes	500,000,000
Total debt outstanding, Fair value	$ 715,330,000	$ 764,781,000
Senior Notes Series A Due February 27, 2020 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	2.72%
Credit facility, amount outstanding	$ 150,000,000	150,000,000
Senior Notes Series B Due February 27, 2023 [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage	3.29%
Credit facility, amount outstanding	$ 350,000,000	$ 350,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Average borrowing under revolving credit facility	249,247,000
Commitment amount	$ 25,000,000
Commitment fee	0.10%
Weighted average interest rate	1.50%
Revolving Credit Facility [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	LIBOR
Basis spread on variable rate	1.00%
Line Of Credit [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 1,012,000
Line Of Credit [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 2,518,000

Taxes on Income, Earnings Before Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Taxes on Income [Abstract]
Earnings before taxes on income - United States	$ 52,370	$ 51,559	$ 62,474	$ 61,343	$ 80,115	$ 90,623	$ 93,072	$ 97,902	$ 227,746	$ 361,712	$ 454,390
Federal [Abstract]
Current									28,919	64,707	81,953
Deferred									49,685	59,582	72,920
State and local									6,338	9,453	14,909
Total provision for taxes on income	$ 19,512	$ 19,206	$ 23,365	$ 22,859	$ 29,043	$ 33,512	$ 34,696	$ 36,491	84,942	133,742	169,782
Tax benefit (expense) realized from equity compensation plans									$ (824)	$ 964	$ 6,119

Taxes on Income, Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Company's provision for taxes on income varied from the statutory federal income tax rate [Abstract]
United States income tax statutory rate	35.00%	35.00%	35.00%
State and local taxes, net of federal benefit	1.80%	1.70%	2.20%
Other - net	0.50%	0.30%	0.20%
Effective income tax rate	37.30%	37.00%	37.40%

Taxes on Income, Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Current deferred tax assets [Abstract]
Compensated absences	$ 739	$ 829
Allowance for doubtful accounts	2,534	3,288
Insurance accruals	6,218	4,234
Other	4,113	3,372
Current deferred tax assets, Total	13,604	11,723
Deferred tax assets [Abstract]
Postretirement health care benefits	2,234	2,501
Insurance accruals	2,910	3,410
Deferred compensation	11,124	10,534
Unrealized loss on defined benefit plans	28,832	25,245
Operating loss carryforwards	7,846	5,188
Other	21,622	20,702
Valuation allowances	(7,417)	(4,716)
Deferred tax assets	67,151	62,864
Deferred tax liabilities [Abstract]
Property	(654,751)	(604,737)
Deferred state taxes	(54,812)	(53,542)
Pension benefits	(2,799)	(8,471)
Goodwill and other intangibles	(51,551)	(44,185)
Other	(22,295)	(21,737)
Deferred tax liabilities	(786,208)	(732,672)
Net deferred tax liabilities	(719,057)	(669,808)
Operating loss carryforwards, net of valuation allowance	$ 429
Expiration dates, operating loss carryforwards	Dec. 31, 2030
Deferred tax assets	$ 88,172	79,303
Deferred tax assets, net of valuation allowance	80,755	$ 74,587
Unrecognized tax benefits including interest and penalties	2,573
Amount that would impact the effective tax rate, if recognized	$ 1,737
Minimum [Member] \| State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2010
Minimum [Member] \| Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2013
Maximum [Member] \| State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2015
Maximum [Member] \| Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2015

Taxes on Income, Reconciliation of Liability for Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits [Roll Forward]
Balance at beginning of year	$ 1,958,000	$ 1,171,000	$ 949,000
Additions based on tax positions related to the current year	187,000	339,000	470,000
Additions for tax positions of prior years	867,000	785,000	39,000
Reductions for tax positions of prior years	(441,000)	(337,000)	(287,000)
Settlements	(552,000)	0	0
Balance at end of year	2,019,000	1,958,000	1,171,000
Income tax penalties and interest recognized	88,000	216,000	40,000
Accrued liabilities for payment of interest and penalties	$ 554,000	$ 522,000	$ 306,000

Leases, Schedule of Rent Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	$ 162,582	$ 166,542	$ 165,257
Other Buildings and Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	11,182	9,383	9,146
Tank Barges [Member] \| Marine Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	13,791	14,092	19,780
Towing Vessels [Member] \| Marine Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	$ 137,609	$ 143,067	$ 136,331
Minimum [Member] \| Tank Barges [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Lease agreements expiring terms	1 year
Minimum [Member] \| Towing Vessels [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Lease agreements expiring terms	30 days
Maximum [Member] \| Tank Barges [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Lease agreements expiring terms	12 years
Maximum [Member] \| Towing Vessels [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Lease agreements expiring terms	5 years

Leases, Schedule of Future Minimum Lease Payments Under Operating Leases (Details) $ in Thousands	Dec. 31, 2016 USD ($)
Operating Leased Assets [Line Items]
2017	$ 106,395
2018	40,299
2019	13,724
2020	11,321
2021	8,581
Thereafter	76,864
Future minimum lease payments under operating leases	257,184
Marine Equipment [Member] \| Tank Barges [Member]
Operating Leased Assets [Line Items]
2017	10,419
2018	8,718
2019	4,581
2020	3,813
2021	1,574
Thereafter	2,474
Future minimum lease payments under operating leases	31,579
Marine Equipment [Member] \| Towing Vessels [Member]
Operating Leased Assets [Line Items]
2017	83,949
2018	20,532
2019	314
2020	0
2021	0
Thereafter	0
Future minimum lease payments under operating leases	104,795
Land Buildings and Equipment [Member]
Operating Leased Assets [Line Items]
2017	12,027
2018	11,049
2019	8,829
2020	7,508
2021	7,007
Thereafter	74,390
Future minimum lease payments under operating leases	$ 120,810

Stock Award Plans (Details) - USD ($)	12 Months Ended
Stock Award Plans (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stock Award Plans [Abstract]
Compensation cost	$ 11,675,000	$ 11,104,000	$ 11,591,000
Income tax benefit	4,378,000	4,120,000	4,358,000
Share-based Compensation Plans Combined Disclosure [Abstract]
Intrinsic value of stock options exercised	266,000	2,555,000	11,671,000
Tax benefit from stock options exercised	100,000	948,000	4,388,000
Intrinsic value of restricted stock vesting	6,928,000	10,270,000	14,847,000
Tax benefit from restricted stock vesting	2,598,000	3,810,000	5,583,000
Fair value of options vested	2,495,000	2,180,000	3,759,000
Fair value of restricted stock vested	$ 6,928,000	$ 10,270,000	$ 14,847,000
Fair value of stock options granted (in dollars per share)	$ 17.30	$ 25.18	$ 36.05
Fair value of stock options granted	$ 3,231,000	$ 2,893,000	$ 4,226,000
Stock Options [Member]
Share-based Compensation Plans Combined Disclosure [Abstract]
Unrecognized compensation cost related to unvested awards	$ 3,422,000
Weighted average period of recognition in years	1 year 4 months 24 days
Fair Value Assumptions [Abstract]
Dividend yield	0.00%	0.00%	0.00%
Average risk-free interest rate	1.50%	1.30%	2.00%
Stock price volatility	30.00%	33.00%	33.00%
Estimated option term	6 years	6 years
Stock Options [Member] \| Minimum [Member]
Fair Value Assumptions [Abstract]
Estimated option term			6 years
Stock Options [Member] \| Maximum [Member]
Fair Value Assumptions [Abstract]
Estimated option term			7 years
Restricted Stock [Member]
Share-based Compensation Plans Combined Disclosure [Abstract]
Unrecognized compensation cost related to unvested awards	$ 18,055,000
Weighted average period of recognition in years	3 years 1 month 6 days
Employee Stock Award Plan [Member]
Stock Award Plan Information [Abstract]
Term of grant	7 years
Vesting period	3 years
Shares available for future grants (in shares)	1,987,512
Options Exercisable [Abstract]
Stock options exercisable (in shares)	321,942	239,518	157,140
Employee Stock Award Plan [Member] \| Stock Options [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start, (in shares)	430,432	322,956	379,604
Granted (in shares)	186,706	114,894	75,204
Exercised (in shares)	0	0	(119,276)
Canceled or expired (in shares)	(16,017)	(7,418)	(12,576)
Outstanding at Period End (in shares)	601,121	430,432	322,956
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start (in dollars per share)	$ 71.01	$ 69.95	$ 55.42
Granted (in dollars per share)	53.50	74.99	98.91
Exercised (in dollars per share)	0	0	42.07
Canceled or expired (in dollars per share)	80.17	86.28	68.89
Outstanding at Period End (in dollars per share)	65.33	$ 71.01	$ 69.95
Employee Stock Award Plan [Member] \| Stock Options [Member] \| First Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	36.35
Range of Exercise Prices, lower limit (in dollars per share)	$ 31.35
Options Outstanding [Abstract]
Number Outstanding (in shares)	16,910
Weighted Average Remaining Contractual Life	1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 32.82
Options Exercisable [Abstract]
Number Exercisable (in shares)	16,910
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 32.82
Employee Stock Award Plan [Member] \| Stock Options [Member] \| Second Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	51.23
Range of Exercise Prices, lower limit (in dollars per share)	$ 46.74
Options Outstanding [Abstract]
Number Outstanding (in shares)	212,335
Weighted Average Remaining Contractual Life	4 years 9 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 50.03
Options Exercisable [Abstract]
Number Exercisable (in shares)	56,629
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 46.74
Employee Stock Award Plan [Member] \| Stock Options [Member] \| Third Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	74.99
Range of Exercise Prices, lower limit (in dollars per share)	$ 64.89
Options Outstanding [Abstract]
Number Outstanding (in shares)	302,735
Weighted Average Remaining Contractual Life	4 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 70.29
Options Exercisable [Abstract]
Number Exercisable (in shares)	202,309
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 69.51
Employee Stock Award Plan [Member] \| Stock Options [Member] \| Fourth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	96.85
Range of Exercise Prices, lower limit (in dollars per share)	$ 93.64
Options Outstanding [Abstract]
Number Outstanding (in shares)	33,987
Weighted Average Remaining Contractual Life	4 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 94.31
Options Exercisable [Abstract]
Number Exercisable (in shares)	22,658
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 94.31
Employee Stock Award Plan [Member] \| Stock Options [Member] \| Fifth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	104.37
Range of Exercise Prices, lower limit (in dollars per share)	$ 101.46
Options Outstanding [Abstract]
Number Outstanding (in shares)	35,154
Weighted Average Remaining Contractual Life	4 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 102.60
Options Exercisable [Abstract]
Number Exercisable (in shares)	23,436
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 102.60
Employee Stock Award Plan [Member] \| Stock Options [Member] \| Full Exercise Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	104.37
Range of Exercise Prices, lower limit (in dollars per share)	$ 31.35
Options Outstanding [Abstract]
Number Outstanding (in shares)	601,121
Weighted Average Remaining Contractual Life	4 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 65.33
Aggregate Intrinsic Value, Options Outstanding	$ 4,175,000
Options Exercisable [Abstract]
Number Exercisable (in shares)	321,942
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 67.73
Aggregate Intrinsic Value, Options Exercisable	$ 1,747,000
Employee Stock Award Plan [Member] \| Restricted Stock [Member]
Unvested Restricted Stock Award Shares [Roll Forward]
Nonvested balance beginning of period (in shares)	311,727	321,453	399,278
Granted (in shares)	190,610	122,740	97,706
Vested (in shares)	(105,109)	(113,958)	(141,870)
Forfeited (in shares)	(19,573)	(18,508)	(33,661)
Nonvested balance end of period (in shares)	377,655	311,727	321,453
Weighted Average Grant Date Fair Value Per Share [Abstract]
Nonvested balance beginning of period (in dollars per share)	$ 75.73	$ 71.04	$ 54.92
Granted (in dollars per share)	53.56	75.04	97.46
Vested (in dollars per share)	69.93	60.73	45.64
Forfeited (in dollars per share)	76.06	82.00	63.56
Nonvested balance end of period (in dollars per share)	$ 66.14	$ 75.73	$ 71.04
2000 Director Plan [Member]
Stock Award Plan Information [Abstract]
Term of grant	10 years
Vesting period	6 months
Shares available for future grants (in shares)	522,457
Options Exercisable [Abstract]
Stock options exercisable (in shares)	205,429	220,429	298,334
2000 Director Plan [Member] \| Stock Options [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start, (in shares)	220,429	298,334	320,322
Granted (in shares)			42,000
Exercised (in shares)	(9,000)	(77,905)	(63,988)
Canceled or expired (in shares)	(6,000)
Outstanding at Period End (in shares)	205,429	220,429	298,334
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start (in dollars per share)	$ 64.37	$ 60.01	$ 50.64
Granted (in dollars per share)			99.52
Exercised (in dollars per share)	35.72	47.65	39.08
Canceled or expired (in dollars per share)	99.52
Outstanding at Period End (in dollars per share)	64.60	$ 64.37	$ 60.01
2000 Director Plan [Member] \| Stock Options [Member] \| First Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	36.82
Range of Exercise Prices, lower limit (in dollars per share)	$ 29.60
Options Outstanding [Abstract]
Number Outstanding (in shares)	21,000
Weighted Average Remaining Contractual Life	10 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 32.69
Options Exercisable [Abstract]
Number Exercisable (in shares)	21,000
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 32.69
2000 Director Plan [Member] \| Stock Options [Member] \| Second Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	56.45
Range of Exercise Prices, lower limit (in dollars per share)	$ 41.24
Options Outstanding [Abstract]
Number Outstanding (in shares)	71,276
Weighted Average Remaining Contractual Life	2 years 8 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 52.34
Options Exercisable [Abstract]
Number Exercisable (in shares)	71,276
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 52.34
2000 Director Plan [Member] \| Stock Options [Member] \| Third Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	62.48
Range of Exercise Prices, lower limit (in dollars per share)	$ 61.89
Options Outstanding [Abstract]
Number Outstanding (in shares)	41,153
Weighted Average Remaining Contractual Life	4 years 9 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 62.34
Options Exercisable [Abstract]
Number Exercisable (in shares)	41,153
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 62.34
2000 Director Plan [Member] \| Stock Options [Member] \| Fourth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	99.52
Range of Exercise Prices, lower limit (in dollars per share)	$ 75.17
Options Outstanding [Abstract]
Number Outstanding (in shares)	72,000
Weighted Average Remaining Contractual Life	5 years 8 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 87.35
Options Exercisable [Abstract]
Number Exercisable (in shares)	72,000
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 87.35
2000 Director Plan [Member] \| Stock Options [Member] \| Sixth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	99.52
Range of Exercise Prices, lower limit (in dollars per share)	$ 29.60
2000 Director Plan [Member] \| Stock Options [Member] \| Full Exercise Price Range [Member]
Options Outstanding [Abstract]
Number Outstanding (in shares)	205,429
Weighted Average Remaining Contractual Life	4 years
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 64.60
Aggregate Intrinsic Value, Options Outstanding	$ 1,891,000
Options Exercisable [Abstract]
Number Exercisable (in shares)	205,429
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 64.60
Aggregate Intrinsic Value, Options Exercisable	$ 1,891,000
2000 Director Plan [Member] \| Restricted Stock [Member]
Unvested Restricted Stock Award Shares [Roll Forward]
Nonvested balance beginning of period (in shares)	1,791	292	384
Granted (in shares)	23,074	20,350	8,160
Vested (in shares)	(24,518)	(18,851)	(8,252)
Nonvested balance end of period (in shares)	347	1,791	292
Weighted Average Grant Date Fair Value Per Share [Abstract]
Nonvested balance beginning of period (in dollars per share)	$ 68.73	$ 99.52	$ 75.65
Granted (in dollars per share)	64.89	78.52	99.52
Vested (in dollars per share)	65.17	79.77	98.41
Nonvested balance end of period (in dollars per share)	$ 64.89	$ 68.73	$ 99.52

Retirement Plans (Details) - USD ($)	12 Months Ended
Retirement Plans (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	7.00%	7.50%
Contribution percentage to defined contribution plan	94.00%
Pension plan defined benefit plan cost increase limit percentage	4.00%
Aggregate contributions to the plans	$ 18,213,000	$ 24,077,000	$ 23,356,000
Seafarers Pension Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	$ 877,000	$ 1,202,000
Contribution percentage to defined contribution plan	100.00%
Maximum contribution limit	5.00%

Retirement Plans, Summary of Asset Allocation (Details)	12 Months Ended
Retirement Plans, Summary of Asset Allocation (Details)	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Asset allocations	100.00%	100.00%
U.S. Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations	51.00%	50.00%
Target allocations, minimum	30.00%
Target allocations	50.00%
Target allocations, maximum	70.00%
International Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations	19.00%	18.00%
Target allocations, minimum	0.00%
Target allocations	20.00%
Target allocations, maximum	30.00%
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations	30.00%	28.00%
Target allocations, minimum	15.00%
Target allocations	30.00%
Target allocations, maximum	55.00%
Cash And Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations	0.00%	4.00%
Target allocations, minimum	0.00%
Target allocations	0.00%
Target allocations, maximum	5.00%

Retirement Plans, Schedule of Change in Benefit Obligation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	$ 297,325	$ 315,075
Service cost	13,402	14,683	$ 10,645
Interest cost	14,123	13,302	12,839
Actuarial loss (gain)	19,120	(39,474)
Gross benefits paid	(6,794)	(6,261)
Benefit obligation at end of year	337,176	297,325	315,075
Accumulated benefit obligation at end of year	272,591	238,775
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	1,526	1,637
Service cost	0	0	0
Interest cost	65	64	73
Actuarial loss (gain)	12	(30)
Gross benefits paid	(146)	(145)
Benefit obligation at end of year	1,457	1,526	1,637
Accumulated benefit obligation at end of year	1,457	1,526
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	891	1,264
Service cost	0	0	0
Interest cost	29	36	110
Actuarial loss (gain)	(198)	(321)
Gross benefits paid	(47)	(88)
Benefit obligation at end of year	675	891	$ 1,264
Accumulated benefit obligation at end of year	$ 675	$ 891

Retirement Plans, Weighted-Average Assumption Used to Determine Benefit Obligation (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.20%	4.50%
Health care cost trend rate [Abstract]
Initial rate	0.00%	0.00%
Ultimate rate	0.00%	0.00%
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.20%	4.50%
Rate of compensation increase	0.00%	0.00%
Health care cost trend rate [Abstract]
Initial rate	0.00%	0.00%
Ultimate rate	0.00%	0.00%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.20%	4.50%
Rate of compensation increase	0.00%	0.00%
Health care cost trend rate [Abstract]
Initial rate	7.00%	6.50%
Ultimate rate	5.00%	5.00%
Years to ultimate	2021	2019

Retirement Plans, Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Increase	$ 0	$ 0
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	0	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Increase	0	0
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Increase	74	107
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	(64)	(93)
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost, Increase	4	5	$ 7
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost, Decrease	$ (3)	$ (4)	$ (6)

Retirement Plans, Summary of Change in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 243,588	$ 242,275
Actual return on plan assets	20,723	(2,426)
Employer contribution	0	10,000
Gross benefits paid	(6,794)	(6,261)
Fair value of plan assets at end of year	257,517	243,588
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	146	145
Gross benefits paid	(146)	(145)
Fair value of plan assets at end of year	0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contribution	47	88
Gross benefits paid	(47)	(88)
Fair value of plan assets at end of year	$ 0	$ 0

Retirement Plans, Summary of Funded Status at End of Year (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 257,517	$ 243,588	$ 242,275
Benefit obligations	(337,176)	(297,325)	(315,075)
Funded status and amount recognized at end of year	(79,659)	(53,737)
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Benefit obligations	(1,457)	(1,526)	(1,637)
Funded status and amount recognized at end of year	(1,457)	(1,526)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Benefit obligations	(675)	(891)	$ (1,264)
Funded status and amount recognized at end of year	$ (675)	$ (891)

Retirement Plans, Amounts Recognized in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	$ 0	$ 0
Current liability	0	0
Long-term liability	(79,659)	(53,737)
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	0	0
Current liability	(150)	(149)
Long-term liability	(1,307)	(1,377)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	0	0
Current liability	(56)	(68)
Long-term liability	$ (619)	$ (823)

Retirement Plans, Amounts Recognized in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$ 87,658	$ 77,940
Prior service cost (credit)	0	0
Accumulated other compensation income	87,658	77,940
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	494	508
Prior service cost (credit)	0	0
Accumulated other compensation income	494	508
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	(5,773)	(6,319)
Prior service cost (credit)	0	0
Accumulated other compensation income	$ (5,773)	$ (6,319)

Retirement Plans, Projected Benefit Obligation in Excess of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 337,176	$ 297,325
Fair value of plan assets at end of year	257,517	243,588
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	1,457	1,526
Fair value of plan assets at end of year	$ 0	$ 0

Retirement Plans, Accumulated Benefit Obligation in Excess of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 337,176	$ 0
Accumulated benefit obligation at end of year	272,591	0
Fair value of plan assets at end of year	257,517	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	1,457	1,526
Accumulated benefit obligation at end of year	1,457	1,526
Fair value of plan assets at end of year	$ 0	$ 0

Retirement Plans, Schedule of Employer Contribution (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	$ 0	$ 0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	153	152
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	$ 50	$ 70

Retirement Plans, Expected Benefit Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	$ 8,032	$ 7,678
Year two	8,835	8,298
Year three	9,646	9,013
Year four	10,400	9,748
Year five	11,201	10,415
Next five years	70,419	63,860
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	153	152
Year two	157	157
Year three	155	154
Year four	151	152
Year five	148	149
Next five years	514	608
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	58	81
Year two	58	86
Year three	58	86
Year four	58	86
Year five	57	85
Next five years	$ 199	$ 341

Retirement Plans, Summary of Expected Federal Subsidy (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	$ 0	$ 0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Next five years	0	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	0	0
Year two	0	0
Year three	0	0
Year four	0	0
Year five	0	0
Next five years	0	0
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	(7)	(11)
Year two	(7)	(11)
Year three	(7)	(11)
Year four	(7)	(12)
Year five	(7)	(12)
Next five years	$ (33)	$ (55)

Retirement Plans, Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2016

Dec. 31, 2015

Dec. 31, 2014

Defined Benefit Plan Disclosure [Line Items]

Recognition of actuarial loss (gain)

^[1]

$ 15,013

$ (19,482)

$ 71,843

Recognition of prior service credit (cost)

^[1]

(4,763)

(6,963)

(68)

Pension Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Service cost

13,402

14,683

10,645

Interest cost

14,123

13,302

12,839

Expected return on plan assets

(16,805)

(17,921)

(18,858)

Actuarial loss (gain)

5,484

7,728

701

Prior service (credit) cost

Net periodic benefit cost

16,204

17,792

5,327

Current year actuarial loss (gain)

15,203

(19,127)

72,737

Recognition of actuarial loss (gain)

(5,484)

(7,728)

(701)

Recognition of prior service credit (cost)

Total recognized in other comprehensive income

9,719

(26,855)

72,036

Total recognized in net periodic benefit cost and other comprehensive income

25,923

(9,063)

77,363

SERP [Member]

Defined Benefit Plan Disclosure [Line Items]

Service cost

Interest cost

Expected return on plan assets

Actuarial loss (gain)

Prior service (credit) cost

Net periodic benefit cost

Current year actuarial loss (gain)

(30)

180

Recognition of actuarial loss (gain)

(26)

(28)

(16)

Recognition of prior service credit (cost)

Total recognized in other comprehensive income

(14)

(58)

164

Total recognized in net periodic benefit cost and other comprehensive income

253

Contingencies and Commitments (Details)	12 Months Ended
Contingencies and Commitments (Details)	Dec. 31, 2016 PotentiallyResponsibleParty Spill BargeSlip Lawsuit Plaintiff	Sep. 13, 2016 USD ($)	Mar. 22, 2014 Vessel
Collision with M/S Summer Wind [Member]
Loss Contingencies [Line Items]
Number of actions filed against the Company \| Lawsuit	2
Number of crewmembers alleging damages \| Plaintiff	2
Amount of civil penalty \| $		$ 4,900,000
Collision with M/S Summer Wind [Member] \| Tank Barge [Member]
Loss Contingencies [Line Items]
Number of vessels involved in collision			2
Number of vessels damaged in collision resulting in fuel oil discharge			1
Collision with M/S Summer Wind [Member] \| Towboat [Member]
Loss Contingencies [Line Items]
Number of vessels involved in collision			1
Portland Harbor Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs") \| PotentiallyResponsibleParty	250
Number of spills \| Spill	4
SBA Shipyard Site [Member]
Site Contingency [Line Items]
Number of barge slips \| BargeSlip	3

Contingencies and Commitments, Certain Significant Risks and Uncertainties (Details) $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016	Dec. 31, 2016 USD ($) State Customers	Dec. 31, 2015 Customers	Dec. 31, 2014 Customers
Guaranties [Abstract]
Issued guaranties	$ 13,983		$ 13,983
Guarantor obligations, expiration period			3 years
Performance Bonds [Member]
Guaranties [Abstract]
Issued guaranties	$ 10,184		$ 10,184
Marine Transportation [Member]
Certain Significant Risks and Uncertainties [Abstract]
Percentage of inland revenue	75.00%	80.00%
Marine Transportation [Member] \| Minimum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts			1 year
Marine Transportation [Member] \| Maximum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts			5 years
Marine Transportation [Member] \| Customers [Member]
Certain Significant Risks and Uncertainties [Abstract]
Percentage of costal revenue			80.00%
Customer relationship period			40 years
Number of single customers accounting more than 10% of segment revenue \| Customers			0	0	0
Diesel Engine Services [Member]
Certain Significant Risks and Uncertainties [Abstract]
Diesel engine services segment's relationship			51 years
Diesel Engine Services [Member] \| Eastern States [Member]
Certain Significant Risks and Uncertainties [Abstract]
Segment operating as authorized distributors \| State			17
Diesel Engine Services [Member] \| Western States [Member]
Certain Significant Risks and Uncertainties [Abstract]
Segment operating as authorized distributors \| State			9
Diesel Engine Services [Member] \| Customers [Member]
Certain Significant Risks and Uncertainties [Abstract]
Number of single customers accounting more than 10% of segment revenue \| Customers			0	0	0
Letters Of Credit [Member]
Guaranties [Abstract]
Issued guaranties	$ 3,799		$ 3,799

Related Party Transactions (Details) - USD ($)	12 Months Ended
Related Party Transactions (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Richard J. Alario [Member]
Related Party Transaction [Line Items]
Oilfield service equipment	$ 80,000	$ 572,000	$ 1,232,000
Hollywood Camp [Member]
Related Party Transaction [Line Items]
Ownership percentage	50.00%
Facility expenses	$ 221,000	1,236,000	1,634,000
Share of facility expenses	3,143,000	2,830,000	2,303,000
Amy D. Husted [Member]
Related Party Transaction [Line Items]
Legal services	$ 779,000	596,000	1,184,000
Bolivar [Member]
Related Party Transaction [Line Items]
Ownership percentage	50.00%
Share of facility expenses	$ 1,314,000	$ 895,000	$ 561,000

Segment Data (Details) $ in Thousands	3 Months Ended								12 Months Ended
Segment Data (Details) $ in Thousands	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) Segment	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Segment Data [Abstract]
Number of reportable segments \| Segment									2
Revenues [Abstract]
Marine transportation									$ 1,471,893	$ 1,663,090	$ 1,770,684
Diesel engine services									298,780	484,442	795,634
Total revenues	$ 435,650	$ 434,708	$ 441,582	$ 458,733	$ 484,138	$ 532,565	$ 543,156	$ 587,673	1,770,673	2,147,532	2,566,318
Segment profit (loss)	52,370	51,559	62,474	61,343	80,115	90,623	93,072	97,902	227,746	361,712	454,390
Total assets	4,303,499				4,152,281				4,303,499	4,152,281	4,137,614
Depreciation and amortization									200,917	192,240	169,312
Capital expenditures									231,066	345,475	355,144
Other segment disclosures [Abstract]
Interest expense	(4,477)	(4,507)	(4,513)	(4,193)	(4,280)	(4,449)	(4,759)	(5,250)	(17,690)	(18,738)	(21,461)
Loss (gain) on disposition of assets	166	122	(94)	(67)	(426)	400	(91)	(1,555)	127	(1,672)	(781)
Other income (expense)	47	$ (120)	$ 179	$ 135	9	$ 22	$ (303)	$ 60	(291)	(663)	(345)
Details of "Other" total assets [Abstract]
Investment in affiliates	2,622				2,090				2,622	2,090
Total assets	4,303,499				4,152,281				4,303,499	4,152,281	4,137,614
Reporting Segments [Member]
Revenues [Abstract]
Marine transportation									1,471,893	1,663,090	1,770,684
Diesel engine services									298,780	484,442	795,634
Other [Member]
Revenues [Abstract]
Segment profit (loss)									(32,542)	(32,051)	(35,537)
Total assets	52,861				63,179				52,861	63,179	83,789
Depreciation and amortization									3,793	3,944	3,830
Capital expenditures									7,728	4,706	7,343
Other segment disclosures [Abstract]
General corporate expenses									(14,966)	(14,773)	(14,896)
Interest expense									(17,690)	(18,738)	(21,461)
Loss (gain) on disposition of assets									(127)	1,672	781
Other income (expense)									241	(212)	39
Profit (loss) from other segment									(32,542)	(32,051)	(35,537)
Details of "Other" total assets [Abstract]
General corporate assets	50,239				61,089				50,239	61,089	81,250
Investment in affiliates	2,622				2,090				2,622	2,090	2,539
Total assets	52,861				63,179				52,861	63,179	83,789
Intersegment Eliminations [Member]
Revenues [Abstract]
Total revenues									24,672	26,203	25,769
Segment profit (loss)									2,467	2,620	2,577
Marine Transportation [Member] \| Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									257,102	374,842	429,864
Total assets	3,622,348				3,451,553				3,622,348	3,451,553	3,317,696
Depreciation and amortization									184,291	175,798	154,019
Capital expenditures									217,423	311,862	340,315
Details of "Other" total assets [Abstract]
Total assets	3,622,348				3,451,553				3,622,348	3,451,553	3,317,696
Diesel Engine Services [Member] \| Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									3,186	18,921	60,063
Total assets	628,290				637,549				628,290	637,549	736,129
Depreciation and amortization									12,833	12,498	11,463
Capital expenditures									5,915	28,907	7,486
Details of "Other" total assets [Abstract]
Total assets	$ 628,290				$ 637,549				$ 628,290	$ 637,549	$ 736,129