Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2015	Feb. 19, 2016	Jun. 30, 2015
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 Common Stock, Shares Outstanding		53,806,000
Entity Public Float			$ 4,137,884,000
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 5,885	$ 24,299
Accounts receivable:
Trade - less allowance for doubtful accounts of $9,374 ($8,887 in 2014)	290,931	417,325
Other	102,443	115,598
Inventories - at lower of average cost or market	184,511	192,354
Prepaid expenses and other current assets	45,283	43,016
Deferred income taxes	11,723	10,562
Total current assets	640,776	803,154
Property and equipment:
Marine transportation equipment	3,806,850	3,495,705
Land, buildings and equipment	252,913	221,693
Property and equipment	4,059,763	3,717,398
Accumulated depreciation	1,280,783	1,127,900
Property and equipment - net	2,778,980	2,589,498
Investment in affiliates	2,090	2,539
Goodwill	586,718	591,405
Other assets	147,702	155,313
Total assets	4,156,266	4,141,909
Current liabilities:
Current portion of long-term debt	0	116,700
Income taxes payable	3,564	3,470
Accounts payable	132,799	222,020
Accrued liabilities:
Interest	5,412	5,610
Insurance premiums and claims	111,705	121,989
Employee compensation	37,243	42,056
Taxes - other than on income	13,525	13,694
Other	16,369	17,684
Deferred revenues	41,300	50,804
Total current liabilities	361,917	594,027
Long-term debt - less current portion	778,834	600,000
Deferred income taxes	669,808	595,769
Other long-term liabilities	66,511	87,200
Total long-term liabilities	$ 1,515,153	$ 1,282,969
Contingencies and commitments
Kirby stockholders' equity:
Common stock, $.10 par value per share. Authorized 120,000,000 shares, issued 59,776,000 in 2015 and 2014	$ 5,978	$ 5,978
Additional paid-in capital	434,783	428,475
Accumulated other comprehensive income - net	(44,686)	(61,037)
Retained earnings	2,200,830	1,974,146
Treasury stock - at cost, 6,056,000 shares in 2015 and 2,906,000 in 2014	(328,094)	(93,526)
Total Kirby stockholders' equity	2,268,811	2,254,036
Noncontrolling interests	10,385	10,877
Total equity	2,279,196	2,264,913
Total liabilities and equity	$ 4,156,266	$ 4,141,909

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Trade, allowance for doubtful accounts	$ 9,374	$ 8,887
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)	6,056,000	2,906,000

CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues:
Marine transportation	$ 1,663,090	$ 1,770,684	$ 1,713,167
Diesel engine services	484,442	795,634	529,028
Total revenues	2,147,532	2,566,318	2,242,195
Costs and expenses:
Costs of sales and operating expenses	1,362,366	1,694,882	1,448,805
Selling, general and administrative	193,237	210,416	177,766
Taxes, other than on income	20,699	16,677	15,893
Depreciation and amortization	192,240	169,312	164,437
Gain on disposition of assets	(1,672)	(781)	(888)
Total costs and expenses	1,766,870	2,090,506	1,806,013
Operating income	380,662	475,812	436,182
Equity in earnings of affiliates	451	384	348
Other income (expense)	(663)	(345)	20
Interest expense	(18,738)	(21,461)	(27,872)
Earnings before taxes on income	361,712	454,390	408,678
Provision for taxes on income	(133,742)	(169,782)	(152,379)
Net earnings	227,970	284,608	256,299
Less: Net earnings attributable to noncontrolling interests	(1,286)	(2,602)	(3,238)
Net earnings attributable to Kirby	$ 226,684	$ 282,006	$ 253,061
Net earnings per share attributable to Kirby common stockholders:
Basic (in dollars per share)	$ 4.12	$ 4.95	$ 4.46
Diluted (in dollars per share)	$ 4.11	$ 4.93	$ 4.44

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($)
$ in Thousands

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]

Net earnings

$ 227,970

$ 284,608

$ 256,299

Other comprehensive income (loss), net of taxes:

Pension and postretirement benefits

16,322

(44,294)

43,274

Foreign currency translation adjustments

(35)

108

Change in fair value of derivative instruments

952

Total other comprehensive income (loss), net of taxes

^[1]

16,351

(44,244)

44,334

Total comprehensive income, net of taxes

244,321

240,364

300,633

Net earnings attributable to noncontrolling interests

(1,286)

(2,602)

(3,238)

Comprehensive income attributable to Kirby

$ 243,035

$ 237,762

$ 297,395

[1]	Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in costs of sales and operating expenses.

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net earnings	$ 227,970	$ 284,608	$ 256,299
Adjustments to reconcile net earnings to net cash provided by operations:
Depreciation and amortization	192,240	169,312	164,437
Provision for doubtful accounts	1,426	3,577	1,260
Provision for deferred income taxes	62,755	77,976	103,056
Gain on disposition of assets	(1,672)	(781)	(888)
Equity in earnings of affiliates, net of distributions and contributions	449	(384)	(348)
Amortization of unearned share-based compensation	11,104	11,591	11,621
Amortization of major maintenance costs	22,126	16,409	9,029
Increase (decrease) in cash flows resulting from changes in:
Accounts receivable	129,908	(176,544)	2,235
Inventory	(7,320)	(56,468)	43,275
Other assets	(14,174)	(11,783)	(47,526)
Income taxes payable	477	(4,544)	313
Accounts payable	(81,808)	44,645	23,088
Accrued and other liabilities	(22,176)	81,295	35,181
Net cash provided by operating activities	521,305	438,909	601,032
Cash flows from investing activities:
Capital expenditures	(345,475)	(355,144)	(253,227)
Acquisitions of businesses and marine equipment, net of cash acquired	(41,250)	(31,800)	(3,643)
Proceeds from disposition of assets	24,429	10,393	33,982
Net cash used in investing activities	(362,296)	(376,551)	(222,888)
Cash flows from financing activities:
Borrowings (payments) on bank credit facilities, net	160,784	75,550	(150,960)
Borrowings on long-term debt	0	0	225,000
Payments on long-term debt	(100,000)	(108,000)	(460,000)
Return of investment to noncontrolling interests	(1,778)	(3,192)	(3,857)
Proceeds from exercise of stock options	3,712	7,519	6,635
Purchase of treasury stock	(241,105)	(15,321)	0
Payment of contingent liability	0	(4,756)	(5,000)
Excess tax benefit from equity compensation plans	964	6,119	3,001
Net cash used in financing activities	(177,423)	(42,081)	(385,181)
Increase (decrease) in cash and cash equivalents	(18,414)	20,277	(7,037)
Cash and cash equivalents, beginning of year	24,299	4,022	11,059
Cash and cash equivalents, end of year	5,885	24,299	4,022
Supplemental disclosures of cash flow information:
Interest paid	20,586	19,622	21,393
Income taxes paid	69,584	90,460	46,136
Capital expenditures included in accounts payable	$ 2,206	$ 0	$ 0

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($)

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, 2012

$ 5,978,000

$ 397,785,000

$ (61,127,000)

$ 1,439,079,000

$ (86,747,000)

$ 12,086,000

Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued

8,276,000

Tax benefit realized from equity compensation plans

3,001,000

$ 3,001,000

Issuance of restricted stock, net of forfeitures

(10,068,000)

Amortization of unearned compensation

11,621,000

Net earnings attributable to Kirby for the year

253,061,000

Purchase of treasury stock (3,316,000 in 2015 and 187,000 in 2014)

Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (166,000 in 2015, 211,000 in 2014 and 261,000 in 2013)

5,493,000

Net earnings attributable to noncontrolling interests

3,238,000

(3,238,000)

Return of investment to noncontrolling interests

(3,857,000)

3,857,000

Other comprehensive income (loss), net of taxes

44,334,000

^[1]

Balance at end of year at Dec. 31, 2013

5,978,000

410,615,000

(16,793,000)

1,692,140,000

(81,254,000)

11,467,000

Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued

8,345,000

Tax benefit realized from equity compensation plans

6,119,000

Issuance of restricted stock, net of forfeitures

(8,195,000)

Amortization of unearned compensation

11,591,000

Net earnings attributable to Kirby for the year

282,006,000

Purchase of treasury stock (3,316,000 in 2015 and 187,000 in 2014)

(15,321,000)

Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (166,000 in 2015, 211,000 in 2014 and 261,000 in 2013)

3,049,000

Net earnings attributable to noncontrolling interests

2,602,000

(2,602,000)

Return of investment to noncontrolling interests

(3,192,000)

3,192,000

Other comprehensive income (loss), net of taxes

(44,244,000)

^[1]

Balance at end of year at Dec. 31, 2014

5,978,000

428,475,000

(61,037,000)

1,974,146,000

(93,526,000)

10,877,000

2,264,913,000

Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued

3,530,000

Tax benefit realized from equity compensation plans

964,000

Issuance of restricted stock, net of forfeitures

(9,290,000)

Amortization of unearned compensation

11,104,000

Net earnings attributable to Kirby for the year

226,684,000

Purchase of treasury stock (3,316,000 in 2015 and 187,000 in 2014)

(241,105,000)

Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (166,000 in 2015, 211,000 in 2014 and 261,000 in 2013)

6,537,000

Net earnings attributable to noncontrolling interests

1,286,000

(1,286,000)

Return of investment to noncontrolling interests

(1,778,000)

1,778,000

Other comprehensive income (loss), net of taxes

16,351,000

^[1]

Balance at end of year at Dec. 31, 2015

$ 5,978,000

$ 434,783,000

$ (44,686,000)

$ 2,200,830,000

$ (328,094,000)

$ 10,385,000

$ 2,279,196,000

[1]	Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in costs of sales and operating expenses.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY [Abstract]
Purchase of treasury stock (in shares)	3,316,000	187,000
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock	$ 166,000	$ 211,000	$ 261,000

Summary of Significant Accounting Policies	12 Months Ended
Summary of Significant Accounting Policies	Dec. 31, 2015
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”). One affiliated limited partnership, in which the Company owns a 50% interest, is the general partner and has effective control and whose activities are an integral part of the operations of the Company, is consolidated. All other 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, 2015 and 2014 were $90,166,000 and $143,615,000, 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, 2015 and 2014 were $77,684,000 and $92,379,000, 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 4, 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 $22,126,000, $16,409,000 and $9,029,000 for the years ended December 31, 2015, 2014 and 2013, 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 $3,026,000 and $639,000 for the years ending December 31, 2015 and 2014, respectively. No interest was capitalized for the year ending December 31, 2013. 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, 2015 and 2014. For 2015 and 2014, 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, 2015 and 2014 was $604,185,000 and $608,872,000, respectively, and accumulated amortization at December 31, 2015 and 2014 was $15,566,000. Accumulated impairment losses were $1,901,000 at December 31, 2015 and 2014. Net goodwill for the marine transportation segment was $381,243,000 at December 31, 2015 and 2014. Net goodwill for the diesel engine services segment was $205,475,000 and $210,162,000 at December 31, 2015 and 2014, respectively. The decrease in net goodwill for the diesel engine services segment was due to a sale of a business during 2015 and the reclassification of certain assets as held for sale as of December 31, 2015. Revenue Recognition. The majority of marine transportation revenue is derived from term contracts, ranging from one to three 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 7, 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 2015, 2014 and 2013 were $23,737,000, $25,416,000 and $22,971,000, 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 November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“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 does not anticipate a material impact on its consolidated financial statements at the time of adoption of this new standard. In July 2015, the FASB issued ASU 2015-11, “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. Subsequent measurement is unchanged for inventory that is measured using last-in, last-out (“LIFO”) or the retail inventory method. 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 or annual reporting period. The Company is currently evaluating the impact of adopting this guidance. 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. ASU 2015-03 requires retrospective application and is effective for the Company for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The Company will adopt the standard in the first quarter of 2016 and does not expect the effect of ASU 2015-03 to have a material impact on the Company’s consolidated financial statements. 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 or cumulative effect transition method. The Company is evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. 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

12 Months Ended

Dec. 31, 2015

Inventories [Abstract]

Inventories

(2) Inventories

The following table presents the details of inventories as of December 31, 2015 and 2014 (in thousands):

	December 31, 2015		December 31, 2014
Finished goods	$	163,501	$	179,760
Work in process		21,010		12,594
	$	184,511	$	192,354

Fair Value Measurements	12 Months Ended
Fair Value Measurements	Dec. 31, 2015
Fair Value Measurements [Abstract]
Fair Value Measurements	(3) 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 4, 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, 2015 and 2014, 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, 2015

Long-Term Debt [Abstract]

Long-Term Debt

(4) Long-Term Debt

Long-term debt at December 31, 2015 and 2014 consisted of the following (in thousands):

	2015		2014
Long-term debt, including current portion:
$550,000,000 revolving credit facility due April 30, 2020	$	278,834	$	—
$325,000,000 revolving credit facility due November 9, 2015		—		116,700
$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		—		—
$540,000,000 term loan due July 1, 2016		—		100,000
	$	778,834	$	716,700

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


2016	$	—
2017		—
2018		—
2019		—
2020		428,834
Thereafter		350,000
	$	778,834

On April 30, 2015, the Company entered into 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. On April 30, 2015, proceeds from the Revolving Credit Facility were used to refinance the outstanding balance of the Company’s previous $325,000,000 unsecured revolving credit facility and the term loan described below. As of December 31, 2015, the Company was in compliance with all Revolving Credit Facility covenants and had $278,834,000 of debt outstanding under the Revolving Credit Facility. The average borrowing under the Revolving Credit Facility during 2015 was $293,451,000, computing by averaging the daily balance, and the weighted average interest rate was 1.3%, 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 $5,047,000 as of December 31, 2015.

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, 2015, 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, 2015. Outstanding letters of credit under the Credit Line were $931,000 as of December 31, 2015.

The Company had a term loan with a group of commercial banks, with Wells Fargo Bank, National Association as the administrative agent bank, with a maturity date of July 1, 2016. On April 30, 2015, the $100,000,000 outstanding balance of the term loan was refinanced with proceeds from the Revolving Credit Facility. The term loan provided for a $540,000,000 five-year unsecured term loan facility with a variable interest rate based on LIBOR or the Alternate Base Rate. The interest rate spread varied with the Company’s senior debt rating and, for the year 2014 through April 29, 2015, was 1.5% over LIBOR or 0.5% over the Alternate Base Rate. The outstanding balance of the term loan was subject to quarterly amortization in increasing amounts and was prepayable, in whole or in part, without penalty. The term loan contained certain restrictive financial covenants including an interest coverage ratio and a debt-to-capitalization ratio. In addition to financial covenants, the term loan contained covenants that, subject to exceptions, restricted 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.

The estimated fair value of total debt outstanding at December 31, 2015 and 2014 was $768,766,000 and $705,215,000, respectively, which differs from the carrying amount of $778,834,000 and $716,700,000, 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, 2015

Taxes on Income [Abstract]

Taxes on Income

(5) Taxes on Income

Earnings before taxes on income and details of the provision for taxes on income for the years ended December 31, 2015, 2014 and 2013 were as follows (in thousands):

	2015		2014		2013
Earnings before taxes on income — United States	$	361,712	$	454,390	$	408,678

Provision for taxes on income:
Federal:
Current	$	64,707	$	81,953	$	41,008
Deferred		59,582		72,920		97,586
State and local		9,453		14,909		13,785
	$	133,742	$	169,782	$	152,379

During the three years ended December 31, 2015, 2014 and 2013, tax benefits related to the exercise of stock options and the issuance of restricted stock that were allocated directly to additional paid-in capital were $964,000, $6,119,000 and $3,001,000, respectively.

The Company’s provision for taxes on income varied from the statutory federal income tax rate for the years ended December 31, 2015, 2014 and 2013 due to the following:

	2015			2014			2013
United States income tax statutory rate		35.0	%		35.0	%		35.0	%
State and local taxes, net of federal benefit		1.7			2.2			2.2
Other – net		.3			.2			.1
		37.0	%		37.4	%		37.3	%

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, 2015 and 2014 were as follows (in thousands):

	2015			2014
Current deferred tax assets:
Compensated absences	$	829		$	854
Allowance for doubtful accounts		3,288			3,111
Insurance accruals		4,234			2,858
Other		3,372			3,739
	$	11,723		$	10,562

Non-current deferred tax assets and liabilities:
Deferred tax assets:
Postretirement health care benefits	$	2,501		$	2,795
Insurance accruals		3,410			3,325
Deferred compensation		10,534			10,157
Unrealized loss on defined benefit plans		25,245			34,501
Operating loss carryforwards		5,188			5,219
Other		20,702			20,687
Valuation allowances		(4,716	)		(4,704	)
		62,864			71,980

Deferred tax liabilities:
Property		(604,737	)		(547,388	)
Deferred state taxes		(53,542	)		(49,503	)
Pension benefits		(8,471	)		(11,198	)
Goodwill and other intangibles		(44,185	)		(37,936	)
Other		(21,737	)		(21,724	)
		(732,672	)		(667,749	)
	$	(669,808	)	$	(595,769	)

The Company has determined that it is more likely than not that all federal deferred tax assets at December 31, 2015 will be realized, including its operating loss carryforwards of $472,000 that expire in various amounts through 2030.

The valuation allowance for state deferred tax assets as of December 31, 2015 and 2014 was $4,716,000 and $4,704,000 respectively, related to the Company’s state net operating loss carryforwards based on the Company’s determination that it is not more likely than not that the deferred tax assets will be realized. Expiration of these state net operating loss carryforwards vary by state through 2035 and none will expire in fiscal 2016.

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 2012 through 2014 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 2009 through 2014 tax years.

As of December 31, 2015, the Company has provided a liability of $2,479,000 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 $1,678,000, 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, 2016 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, 2015, 2014 and 2013, is as follows (in thousands):

	2015			2014			2013
Balance at beginning of year	$	1,171		$	949		$	1,045
Additions based on tax positions related to the current year		339			470			239
Additions for tax positions of prior years		785			39			114
Reductions for tax positions of prior years		(337	)		(287	)		(413	)
Settlements		—			—			(36	)
Balance at end of year	$	1,958		$	1,171		$	949

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 (credit) of $216,000, $40,000 and $(421,000) in interest and penalties for the years ended December 31, 2015, 2014 and 2013, respectively. The Company had $522,000, $306,000 and $266,000 of accrued liabilities for the payment of interest and penalties at December 31, 2015, 2014 and 2013, respectively.

Leases

12 Months Ended

Dec. 31, 2015

Leases [Abstract]

Leases

(6) 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 2020. 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, 2015, 2014 and 2013 was as follows (in thousands):

	2015		2014		2013
Rental expense:
Marine equipment — barges	$	14,092	$	19,780	$	20,841
Marine equipment — towing vessels		143,067		136,331		124,877
Other buildings and equipment		9,383		9,146		10,298
Rental expense	$	166,542	$	165,257	$	156,016

Future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year at December 31, 2015 were as follows (in thousands):

	Land, Buildings		Marine Equipment
	And Equipment		Barges		Towing Vessels		Total
2016	$	7,654	$	11,751	$	100,124	$	119,529
2017		6,806		10,544		46,362		63,712
2018		6,166		8,843		20,732		35,741
2019		4,375		3,856		317		8,548
2020		3,570		2,239		—		5,809
Thereafter		13,519		—		—		13,519
	$	42,090	$	37,233	$	167,535	$	246,858

Stock Award Plans

12 Months Ended

Dec. 31, 2015

Stock Award Plans [Abstract]

Stock Award Plans

(7) 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, 2015, 2014 and 2013 were as follows (in thousands):

	2015		2014		2013
Compensation cost	$	11,104	$	11,591	$	11,621
Income tax benefit	$	4,120	$	4,358	$	4,370

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. The terms of the options are seven years and vest ratably over three years. No performance awards payable in stock have been awarded under the plan. At December 31, 2015, 2,329,238 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, 2015, 2014 and 2013:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2012		351,173		$	45.54
Granted		111,527		$	70.94
Exercised		(83,096	)	$	34.51
Canceled or expired		—		$	—
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

Under the employee plan, stock options exercisable were 239,518, 157,140 and 175,170 at December 31, 2015, 2014 and 2013, respectively.

The following table summarizes information about the Company’s outstanding and exercisable stock options under the employee plan at December 31, 2015:

		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		1.1	$	32.82				16,910	$	32.82
$	46.74		56,629		2.1	$	46.74				56,629	$	46.74
$	65.28 – $74.99		283,963		4.6	$	70.98				141,669	$	67.90
$	93.64 – $96.85		35,763		5.1	$	94.27				11,921	$	94.27
$	101.46 – $114.11		37,167		5.2	$	103.22				12,389	$	103.22
$	31.35 – $114.11		430,432		4.2	$	71.01	$	668,000		239,518	$	63.56	$	668,000

The following is a summary of the restricted stock award activity under the employee plan described above for the years ended December 31, 2015, 2014 and 2013:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2012		418,128		$	45.39
Granted		139,971		$	69.85
Vested		(149,162	)	$	44.30
Forfeited		(9,659	)	$	61.20
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

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 vest 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, 2015, 539,531 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, 2015, 2014, and 2013:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2012		345,938		$	45.84
Granted		54,958		$	75.17
Exercised		(80,574	)	$	46.75
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
Granted		—		$	—
Exercised		(77,905	)	$	47.65
Outstanding at December 31, 2015		220,429		$	64.37

Under the director plan, options exercisable were 220,429, 298,334 and 320,082 at December 31, 2015, 2014 and 2013, respectively.

The following table summarizes information about the Company’s outstanding and exercisable stock options under the director plan at December 31, 2015:

	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		30,000		1.9	$	33.60				30,000	$	33.60
$41.24 – $56.45		71,276		4.3	$	52.34				71,276	$	52.34
$61.89 – $62.48		41,153		6.5	$	62.34				41,153	$	62.34
$75.17 – $99.52		78,000		7.3	$	88.28				78,000	$	88.28
$29.60 – $99.52		220,429		5.4	$	64.37	$	775,000		220,429	$	64.37	$	775,000

The following is a summary of the restricted stock award activity under the director plan described above for the years ended December 31, 2015, 2014 and 2013:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2012		348		$	62.99
Granted		10,536		$	75.65
Vested		(10,500	)	$	75.23
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

The total intrinsic value of all stock options exercised under all of the Company’s plans was $2,555,000, $11,671,000 and $6,703,000 for the years ended December 31, 2015, 2014 and 2013, respectively. The actual tax benefit realized for tax deductions from stock option exercises was $948,000, $4,388,000 and $2,520,000 for the years ended December 31, 2015, 2014 and 2013, respectively.

The total intrinsic value of all the restricted stock vestings under all of the Company’s plans was $10,270,000, $14,847,000 and $10,993,000 for the years ended December 31, 2015, 2014 and 2013, respectively. The actual tax benefit realized for tax deductions from restricted stock vestings was $3,810,000, $5,583,000 and $4,133,000 for the years ended December 31, 2015, 2014 and 2013, respectively.

As of December 31, 2015, there was $2,956,000 of unrecognized compensation cost related to nonvested stock options and $16,920,000 related to restricted stock. The stock options are expected to be recognized over a weighted average period of approximately 1.2 years and restricted stock over approximately 2.8 years. The total fair value of stock options vested was $2,180,000, $3,759,000 and $3,341,000 during the years ended December 31, 2015, 2014 and 2013, respectively. The fair value of the restricted stock vested was $10,270,000, $14,847,000 and $10,993,000 for the years ended December 31, 2015, 2014 and 2013, respectively.

The weighted average per share fair value of stock options granted during the years ended December 31, 2015, 2014 and 2013 was $25.18, $36.05 and $25.14, respectively. The fair value of the stock options granted during the years ended December 31, 2015, 2014 and 2013 was $2,893,000, $4,226,000 and $4,184,000, 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, 2015, 2014 and 2013 were as follows:

	2015			2014			2013
Dividend yield	None			None			None
Average risk-free interest rate		1.3	%		2.0	%		1.1	%
Stock price volatility		33	%		33	%		34	%
Estimated option term		Six years			Six years or seven years			Six years or seven years

Retirement Plans

12 Months Ended

Dec. 31, 2015

Retirement Plans [Abstract]

Retirement Plans

(8) 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 $243,588,000 and $242,275,000 at December 31, 2015 and 2014 respectively. As of December 31, 2015 and 2014, these assets were allocated among asset categories as follows:

Asset Category	2015			2014			Current Minimum, Target and Maximum Allocation Policy
U.S. equity securities		50	%		52	%		30% — 50%— 70	%
International equity securities		18	%		18	%		0% — 20%— 30	%
Debt securities		28	%		30	%		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 7.5% in 2015 and 2014. 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 102% of the pension plan’s ABO at December 31, 2015.

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
	2015			2014			2015			2014			2015			2014
Change in benefit obligation
Benefit obligation at beginning of year	$	315,075		$	249,960		$	1,637		$	1,529		$	1,264		$	2,307
Service cost		14,683			10,645			—			—			—			—
Interest cost		13,302			12,839			64			73			36			110
Actuarial loss (gain)		(39,474	)		66,640			(30	)		180			(321	)		(1,065	)
Gross benefits paid		(6,261	)		(25,009	)		(145	)		(145	)		(88	)		(88	)
Benefit obligation at end of year	$	297,325		$	315,075		$	1,526		$	1,637		$	891		$	1,264

Accumulated benefit obligation at end of year	$	238,775		$	241,592		$	1,526		$	1,637		$	—		$	—

Weighted-average assumption used to determine benefit obligation at end of year
Discount rate		4.5	%	4.1	%	4.5	%	4.1	%	4.5	%	4.1	%
Rate of compensation increase	Age-based table			4.25	%	—		—		—		—
Health care cost trend rate
Initial rate		—		—		—		—		6.5	%	7.0	%
Ultimate rate		—		—		—		—		5.0	%	5.0	%
Years to ultimate		—		—		—		—		2019		2019

Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation
Increase	$	—	$	—	$	—	$	—	$	107		$	167
Decrease		—		—		—		—		(93	)		(141	)

Change in plan assets
Fair value of plan assets at beginning of year	$	242,275		$	254,523		$	—		$	—		$	—		$	—
Actual return on plan assets		(2,426	)		12,761			—			—			—			—
Employer contribution		10,000			—			145			145			88			88
Gross benefits paid		(6,261	)		(25,009	)		(145	)		(145	)		(88	)		(88	)
Fair value of plan assets at end of year	$	243,588		$	242,275		$	—		$	—		$	—		$	—

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, 2015 and 2014 (in thousands):

													Other Postretirement Benefits
	Pension Benefits												Postretirement
	Pension Plan						SERP						Welfare Plan
	2015			2014			2015			2014			2015			2014
Funded status at end of year
Fair value of plan assets	$	243,588		$	242,275		$	—		$	—		$	—		$	—
Benefit obligations		297,325			315,075			1,526			1,637			891			1,264
Funded status and amount recognized at end of year	$	(53,737	)	$	(72,800	)	$	(1,526	)	$	(1,637	)	$	(891	)	$	(1,264	)

Amounts recognized in the consolidated balance sheets
Noncurrent asset	$	—		$	—		$	—		$	—		$	—		$	—
Current liability		—			—			(149	)		(141	)		(68	)		(83	)
Long-term liability		(53,737	)		(72,800	)		(1,377	)		(1,496	)		(823	)		(1,181	)

Amounts recognized in accumulated other comprehensive income
Net actuarial loss (gain)	$	77,940	$	104,795	$	508	$	566	$	(6,319	)	$	(6,787	)
Prior service cost (credit)		—		—		—		—		—			—
Accumulated other compensation income	$	77,940	$	104,795	$	508	$	566	$	(6,319	)	$	(6,787	)

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, 2015 and 2014 were as follows (in thousands):

	Pension Benefits
	Pension Plan						SERP
	2015			2014			2015			2014
Projected benefit obligation in excess of plan assets
Projected benefit obligation at end of year		$	297,325		$	315,075		$	1,526		$	1,637
Fair value of plan assets at end of year			243,588			242,275			—			—

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, 2015 and 2014 were as follows (in thousands):

	Pension Benefits
	Pension Plan						SERP
	2015			2014			2015			2014
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation at end of year		$	—		$	—		$	1,526		$	1,637
Accumulated benefit obligation at end of year			—			—			1,526			1,637
Fair value of plan assets at end of year			—			—			—			—

The following tables presents the expected cash flows for the Company’s defined benefit plans and postretirement benefit plan at December 31, 2015 and 2014 (in thousands):

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2015		2014		2015		2014		2015		2014
Expected employer contributions
First year	$	—	$	8,400	$	152	$	143	$	70	$	84

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2015		2014		2015		2014		2015		2014
Expected benefit payments (gross)
Year one	$	7,678	$	7,100	$	152	$	143	$	81	$	96
Year two		8,298		7,672		157		151		86		98
Year three		9,013		8,333		154		155		86		103
Year four		9,748		9,080		152		153		86		95
Year five		10,415		9,868		149		150		85		94
Next five years		63,860		62,666		608		621		341		445

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2015		2014		2015		2014		2015			2014
Expected federal subsidy
Year one	$	—	$	—	$	—	$	—	$	(11	)	$	(11	)
Year two		—		—		—		—		(11	)		(11	)
Year three		—		—		—		—		(11	)		(11	)
Year four		—		—		—		—		(12	)		(12	)
Year five		—		—		—		—		(12	)		(12	)
Next five years		—		—		—		—		(55	)		(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, 2015, 2014 and 2013 were as follows (in thousands):

	Pension Benefits
	Pension Plan									SERP
	2015			2014			2013			2015			2014			2013
Components of net periodic benefit cost
Service cost	$	14,683		$	10,645		$	12,824		$	—		$	—		$	—
Interest cost		13,302			12,839			11,400			64			73			70
Expected return on plan assets		(17,921	)		(18,858	)		(16,127	)		—			—			—
Amortization:
Actuarial loss		7,728			701			8,276			28			16			19
Prior service credit		—			—			—			—			—			—
Net periodic benefit cost		17,792			5,327			16,373			92			89			89

Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		(19,127	)		72,737			(61,759	)		(30	)		180			(138	)
Recognition of actuarial loss		(7,728	)		(701	)		(8,276	)		(28	)		(16	)		(19	)
Recognition of prior service credit		—			—			—			—			—			—
Total recognized in other comprehensive income		(26,855	)		72,036			(70,035	)		(58	)		164			(157	)

Total recognized in net periodic benefit cost and other comprehensive income	$	(9,063	)	$	77,363		$	(53,662	)	$	34		$	253		$	(68	)

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

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2016 are as follows (in thousands):

	Pension Benefits
	Pension Plan		SERP
Actuarial loss	$	4,924	$	26
Prior service credit		—		—
	$	4,924	$	26

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, 2015, 2014 and 2013 were as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
	2015			2014			2013
Components of net periodic benefit cost
Service cost	$	—		$	—		$	—
Interest cost		36			110			112
Amortization:
Actuarial gain		(793	)		(649	)		(620	)
Prior service cost		—			—			—
Net periodic benefit cost		(757	)		(539	)		(508	)

Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial gain		(322	)		(1,065	)		(600	)
Recognition of actuarial gain		793			649			620
Recognition of prior service cost		—			—			—
Adjustment for actual Medicare Part D reimbursement		(3	)		(8	)		(5	)
Total recognized in other comprehensive income		468			(424	)		15

Total recognized in net periodic benefit cost and other comprehensive income	$	(289	)	$	(963	)	$	(493	)

Weighted average assumptions used to determine net periodic benefit cost
Discount rate	4.1	%	5.0	%	4.1	%
Health care cost trend rate:
Initial rate	7.0	%	7.0	%	7.5	%
Ultimate rate	5.0	%	5.0	%	5.0	%
Years to ultimate	2019		2018		2018

Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost
Increase	$	5		$	7		$	10
Decrease		(4	)		(6	)		(9	)

The estimated amounts that will be amortized from accumulated other comprehensive income into net periodic benefit cost in 2016 are as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
Actuarial gain	$	(745	)
Prior service cost		—
	$	(745	)

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 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 2015 and 2014, the Company made contributions of $1,202,000 and $1,290,000, respectively, to the SPT and none of the Company’s contributions to the SPT exceeded 5% of total contributions to the SPT nor did the Company pay any material surcharges.

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 2015 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 2014 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, 2014, 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 $24,077,000, $23,356,000 and $23,158,000 in 2015, 2014 and 2013, respectively.

Other Comprehensive Income

12 Months Ended

Dec. 31, 2015

Other Comprehensive Income [Abstract]

Other Comprehensive Income

(9) Other Comprehensive Income

The Company’s changes in other comprehensive income for the years ended December 31, 2015, 2014 and 2013 were as follows (in thousands):

	2015							2014									2013
	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	$	6,963	$	(2,667	)	$	4,296	$	68		$	(26	)	$	42		$	7,675		$	(2,942	)	$	4,733
Actuarial gains (losses)		19,482		(7,456	)		12,026		(71,843	)		27,507			(44,336	)		62,503			(23,962	)		38,541

Foreign currency translation adjustments		29		—			29		(35	)		—			(35	)		108			—			108

Change in fair value of derivative instruments (b):
Unrealized gains (losses)		—		—			—		24			(9	)		15			2,851			(996	)		1,855
Reclassified to net earnings		—		—			—		121			(51	)		70			(1,389	)		486			(903	)
Total	$	26,474	$	(10,123	)	$	16,351	$	(71,665	)	$	27,421		$	(44,244	)	$	71,748		$	(27,414	)	$	44,334

(a)	Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 8 – 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, 2015

Earnings Per Share [Abstract]

Earnings Per Share

(10) Earnings Per Share

The following table presents the components of basic and diluted earnings per share for the years ended December 31, 2015, 2014 and 2013 (in thousands, except per share amounts):

	2015			2014			2013
Net earnings attributable to Kirby	$	226,684		$	282,006		$	253,061
Undistributed earnings allocated to restricted shares		(1,345	)		(1,643	)		(1,819	)
Income available to Kirby common stockholders — basic		225,339			280,363			251,242
Undistributed earnings allocated to restricted shares		1,345			1,643			1,819
Undistributed earnings reallocated to restricted shares		(1,343	)		(1,637	)		(1,813	)
Income available to Kirby common stockholders — diluted	$	225,341		$	280,369		$	251,248

Shares outstanding:
Weighted average common stock issued and outstanding		55,056			57,006			56,762
Weighted average unvested restricted stock		(327	)		(332	)		(408	)
Weighted average common stock outstanding — basic		54,729			56,674			56,354
Dilutive effect of stock options		97			193			198
Weighted average common stock outstanding — diluted		54,826			56,867			56,552
Net earnings per share attributable to Kirby common stockholders:
Basic	$	4.12		$	4.95		$	4.46

Diluted	$	4.11		$	4.93		$	4.44

Certain outstanding options to purchase approximately 227,000, 75,000 and 2,000 shares of common stock were excluded in the computation of diluted earnings per share as of December 31, 2015, 2014 and 2013, respectively, as such stock options would have been antidilutive.

Quarterly Results (Unaudited)

12 Months Ended

Dec. 31, 2015

Quarterly Results (Unaudited) [Abstract]

Quarterly Results (Unaudited)

(11) Quarterly Results (Unaudited)

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

The unaudited quarterly results for the year ended December 31, 2014 were as follows (in thousands, except per share amounts):

	Three Months Ended
	March 31, 2014			June 30, 2014			September 30, 2014			December 31, 2014
Revenues	$	589,246		$	628,054		$	680,721		$	668,297
Costs and expenses		482,443			501,556			552,642			554,646
Gain on disposition of assets		51			527			47			156
Operating income		106,854			127,025			128,126			113,807
Other income (expense)		(236	)		123			27			125
Interest expense		(5,618	)		(5,469	)		(5,225	)		(5,149	)
Earnings before taxes on income		101,000			121,679			122,928			108,783
Provision for taxes on income		(37,989	)		(45,768	)		(45,715	)		(40,310	)
Net earnings		63,011			75,911			77,213			68,473
Less: Net earnings attributable to noncontrolling interests		(765	)		(919	)		(496	)		(422	)
Net earnings attributable to Kirby	$	62,246		$	74,992		$	76,717		$	68,051

Net earnings per share attributable to Kirby common stockholders:
Basic	$	1.09		$	1.32		$	1.34		$	1.19
Diluted	$	1.09		$	1.31		$	1.34		$	1.19

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, 2015
Contingencies and Commitments [Abstract]
Contingencies and Commitments	(12) Contingencies and Commitments In June 2011, the Company as well as three other companies received correspondence from the United States Environmental Protection Agency (“EPA”) concerning ongoing cleanup and restoration activities under the Comprehensive Environmental Response, Compensation and Liability Act (“CERCLA”) with respect to a Superfund site, the Gulfco Marine Maintenance Site (“Gulfco”), located in Freeport, Texas. In prior years, various subsidiaries of the Company utilized a successor to Gulfco to perform tank barge cleaning services, sand blasting and repair on certain Company vessels. Since 2005, four named Potentially Responsible Parties (“PRPs”) have participated in the investigation, cleanup and restoration of the site under an administrative order from EPA. Information provided by the PRPs indicates that approximately $9,943,000 was incurred in connection with the cleanup effort. The EPA has incurred oversight costs of approximately $2,258,000. The named PRPs filed suit against the Company and approximately 21 other defendants seeking contribution and indemnity under CERCLA for costs incurred in connection with its activities in cleaning up the Gulfco Site. The Company and other nonparticipating PRPs continue to address settlement terms related to this matter with the Gulfco Restoration Group. In 2009, the Company was named a PRP in addition to a group of approximately 250 named PRPs under 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 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 2000, the Company and a group of approximately 45 other companies were notified that they are PRPs under CERCLA with respect to a Superfund site, the Palmer Barge Line Superfund Site (“Palmer”), located in Port Arthur, Texas. In prior years, Palmer had provided tank barge cleaning services to various subsidiaries of the Company. The Company and three other PRPs entered into an agreement with the EPA to perform a remedial investigation and feasibility study and, subsequently, a limited remediation was performed and is now complete. During the 2007 third quarter, five new PRPs entered into an agreement with the EPA related to the Palmer site. In July 2008, the EPA sent a letter to approximately 30 PRPs for the Palmer site, including the Company, indicating that it intends to pursue recovery of $2,949,000 of costs it incurred in relation to the site. The Company and the other PRPs have resolved the EPA’s past costs claim which was approved by the EPA and Department of Justice. The Company has funded its contribution to settlement and the Consent Decree has been granted by the Court fulfilling all procedural requirements of the settlement. 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. 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 July 25, 2011, a subsidiary of the Company was named as a defendant in the U.S. District Court for the Southern District of Texas - Galveston Division, in a complaint styled Figgs. v. Kirby Inland Marine, LP (“Kirby Inland Marine”), et al., which alleges that the plaintiff individually as a vessel tankerman, and on behalf of other current and former similarly situated vessel tankermen employed with the Company, is entitled to overtime pay under the Fair Labor Standards Act. Plaintiffs assert that vessel tankermen are not seamen who are expressly exempt from overtime pay provisions under the law. The case was conditionally certified as a collective action on December 22, 2011 at which time the Court prescribed a notice period for current and former employees to voluntarily participate as plaintiffs. The notice period closed on February 27, 2012. Plaintiffs seek compensatory damages in the form of back pay, attorneys’ fees, cost and liquidated damages. In a recent case that presented substantially the same facts and legal issues, the United States Court of Appeals for the Fifth Circuit ruled that vessel tankermen are seamen who are exempt from the overtime pay provisions of the Fair Labor Standards Act. While the Figgs case is still pending, the Company believes that, after the Fifth Circuit ruling, it will incur no material liability in the case. 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 National Transportation Safety Board 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. There is a separate process for making a claim under the Oil Pollution Act of 1990 (“OPA”). The Company is processing claims properly presented, documented and recoverable under OPA. The Company is named as a party in other lawsuits filed in connection with this incident which are currently stayed by orders entered into by the court in the limitation proceedings, some of which may also have been presented as claims in the limitation proceeding. The actions include allegation of business interruption, loss of profit, loss of use of natural resources and seek unspecified economic and compensatory damages. In addition, the Company has received claims from numerous parties claiming property damage and various economic damages. 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 litigation and claims process is ongoing. In December 2015, the Company submitted evidence in the liability trial in connection with the consolidated limitation actions. The damages phase of the trial is scheduled for the second quarter of 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 the major industrial petrochemical and chemical manufacturers, refining companies and agricultural chemical manufacturers operating in the United States. During 2015, approximately 80% of marine transportation’s inland revenues were from movements of such products under term contracts, typically ranging from one year to three years, some with renewal options. During 2015, 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 2015, 2014 and 2013. 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 USCG and United States Navy, and power generation, nuclear and industrial companies. The segment operates as an authorized distributor in 17 eastern states and the Caribbean, and as non-exclusive authorized service centers for Electro-Motive Diesel, Inc. (“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 50 years. The segment also operates factory-authorized full service marine dealerships for Cummins, Detroit Diesel and John Deere high-speed diesel engines and Allison transmissions and 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 exclusive distributor for 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 2015, 2014 and 2013. 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 $19,968,000 at December 31, 2015, including $6,299,000 in letters of credit and $13,669,000 in performance bonds. All of these instruments have an expiration date within four 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, 2015

Segment Data [Abstract]

Segment Data

(13) 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 $26,203,000, $25,769,000 and $27,669,000 in 2015, 2014 and 2013, respectively, as well as the related intersegment profit of $2,620,000, $2,577,000 and $2,767,000 in 2015, 2014 and 2013, 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, 2015, 2014 and 2013 (in thousands):

	2015			2014			2013
Revenues:
Marine transportation	$	1,663,090		$	1,770,684		$	1,713,167
Diesel engine services		484,442			795,634			529,028
	$	2,147,532		$	2,566,318		$	2,242,195
Segment profit (loss):
Marine transportation	$	374,842		$	429,864		$	408,255
Diesel engine services		18,921			60,063			42,767
Other		(32,051	)		(35,537	)		(42,344	)
	$	361,712		$	454,390		$	408,678
Total assets:
Marine transportation	$	3,451,553		$	3,317,696		$	3,046,692
Diesel engine services		637,549			736,129			576,472
Other		67,164			88,084			59,353
	$	4,156,266		$	4,141,909		$	3,682,517
Depreciation and amortization:
Marine transportation	$	175,798		$	154,019		$	149,574
Diesel engine services		12,498			11,463			11,096
Other		3,944			3,830			3,767
	$	192,240		$	169,312		$	164,437
Capital expenditures:
Marine transportation	$	311,862		$	340,315		$	237,964
Diesel engine services		28,907			7,486			4,658
Other		4,706			7,343			10,605
	$	345,475		$	355,144		$	253,227

The following table presents the details of “Other” segment profit (loss) for the years ended December 31, 2015, 2014 and 2013 (in thousands):

	2015			2014			2013
General corporate expenses	$	(14,773	)	$	(14,896	)	$	(15,728	)
Interest expense		(18,738	)		(21,461	)		(27,872	)
Gain on disposition of assets		1,672			781			888
Other income (expense)		(212	)		39			368
	$	(32,051	)	$	(35,537	)	$	(42,344	)

The following table presents the details of “Other” total assets as of December 31, 2015, 2014 and 2013 (in thousands):

	2015		2014		2013
General corporate assets	$	65,074	$	85,545	$	57,197
Investment in affiliates		2,090		2,539		2,156
	$	67,164	$	88,084	$	59,353

- 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 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
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Reference 9: http://www.xbrl.org/2003/role/presentationRef
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Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
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+ Details

Related Party Transactions	12 Months Ended
Related Party Transactions	Dec. 31, 2015
Related Party Transactions [Abstract]
Related Party Transactions	(14) Related Party Transactions Richard J. Alario, a current director of the Company, is Chief Executive Officer of Key Energy Services, Inc. (“Key Energy”). Key Energy paid the Company $572,000 in 2015, $1,232,000 in 2014 and $1,973,000 in 2013 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 $1,236,000 in 2015, $1,634,000 in 2014 and $1,112,000 in 2013 for use of the facility. The Company paid The Hollywood Camp $2,830,000 in 2015, $2,303,000 in 2014 and $2,044,000 in 2013 for its share of facility expenses. The husband of Amy D. Husted, Vice President — Legal of the Company, is a partner in the law firm of Strasburger & Price, LLP. The Company paid the law firm $596,000 in 2015, $1,184,000 in 2014 and $851,000 in 2013 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 $895,000 in 2015, $561,000 in 2014 and $703,000 in 2013 for barge fleeting services. Such services were in the ordinary course of business of the Company.

- Definition

The entire disclosure for related party transactions. Examples of related party transactions include transactions between (a) a parent company and its subsidiary; (b) subsidiaries of a common parent; (c) and entity and its principal owners; and (d) affiliates.

+ References + Details

Summary of Significant Accounting Policies (Policies)	12 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2015
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”). One affiliated limited partnership, in which the Company owns a 50% interest, is the general partner and has effective control and whose activities are an integral part of the operations of the Company, is consolidated. All other 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, 2015 and 2014 were $90,166,000 and $143,615,000, 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, 2015 and 2014 were $77,684,000 and $92,379,000, 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 4, 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 $22,126,000, $16,409,000 and $9,029,000 for the years ended December 31, 2015, 2014 and 2013, 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 $3,026,000 and $639,000 for the years ending December 31, 2015 and 2014, respectively. No interest was capitalized for the year ending December 31, 2013.
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, 2015 and 2014. For 2015 and 2014, 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, 2015 and 2014 was $604,185,000 and $608,872,000, respectively, and accumulated amortization at December 31, 2015 and 2014 was $15,566,000. Accumulated impairment losses were $1,901,000 at December 31, 2015 and 2014. Net goodwill for the marine transportation segment was $381,243,000 at December 31, 2015 and 2014. Net goodwill for the diesel engine services segment was $205,475,000 and $210,162,000 at December 31, 2015 and 2014, respectively. The decrease in net goodwill for the diesel engine services segment was due to a sale of a business during 2015 and the reclassification of certain assets as held for sale as of December 31, 2015.
Revenue Recognition	Revenue Recognition. The majority of marine transportation revenue is derived from term contracts, ranging from one to three 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 7, 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 2015, 2014 and 2013 were $23,737,000, $25,416,000 and $22,971,000, 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 November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“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 does not anticipate a material impact on its consolidated financial statements at the time of adoption of this new standard. In July 2015, the FASB issued ASU 2015-11, “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. Subsequent measurement is unchanged for inventory that is measured using last-in, last-out (“LIFO”) or the retail inventory method. 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 or annual reporting period. The Company is currently evaluating the impact of adopting this guidance. 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. ASU 2015-03 requires retrospective application and is effective for the Company for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years. Early adoption is permitted for financial statements that have not been previously issued. The Company will adopt the standard in the first quarter of 2016 and does not expect the effect of ASU 2015-03 to have a material impact on the Company’s consolidated financial statements. 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 or cumulative effect transition method. The Company is evaluating the effect that ASU 2014-09 will have on its consolidated financial statements and related disclosures. The Company has not yet selected a transition method nor has it determined the effect of ASU 2014-09 on its ongoing financial reporting.

Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2015

Long-Term Debt [Abstract]

Schedule of Long-Term Debt

Long-term debt at December 31, 2015 and 2014 consisted of the following (in thousands):

	2015		2014
Long-term debt, including current portion:
$550,000,000 revolving credit facility due April 30, 2020	$	278,834	$	—
$325,000,000 revolving credit facility due November 9, 2015		—		116,700
$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		—		—
$540,000,000 term loan due July 1, 2016		—		100,000
	$	778,834	$	716,700

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):


2016	$	—
2017		—
2018		—
2019		—
2020		428,834
Thereafter		350,000
	$	778,834

Taxes on Income (Tables)

12 Months Ended

Dec. 31, 2015

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, 2015, 2014 and 2013 were as follows (in thousands):

	2015		2014		2013
Earnings before taxes on income — United States	$	361,712	$	454,390	$	408,678

Provision for taxes on income:
Federal:
Current	$	64,707	$	81,953	$	41,008
Deferred		59,582		72,920		97,586
State and local		9,453		14,909		13,785
	$	133,742	$	169,782	$	152,379

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, 2015, 2014 and 2013 due to the following:

	2015			2014			2013
United States income tax statutory rate		35.0	%		35.0	%		35.0	%
State and local taxes, net of federal benefit		1.7			2.2			2.2
Other – net		.3			.2			.1
		37.0	%		37.4	%		37.3	%

Schedule of Deferred Tax Assets and Liabilities

	2015			2014
Current deferred tax assets:
Compensated absences	$	829		$	854
Allowance for doubtful accounts		3,288			3,111
Insurance accruals		4,234			2,858
Other		3,372			3,739
	$	11,723		$	10,562

Non-current deferred tax assets and liabilities:
Deferred tax assets:
Postretirement health care benefits	$	2,501		$	2,795
Insurance accruals		3,410			3,325
Deferred compensation		10,534			10,157
Unrealized loss on defined benefit plans		25,245			34,501
Operating loss carryforwards		5,188			5,219
Other		20,702			20,687
Valuation allowances		(4,716	)		(4,704	)
		62,864			71,980

Deferred tax liabilities:
Property		(604,737	)		(547,388	)
Deferred state taxes		(53,542	)		(49,503	)
Pension benefits		(8,471	)		(11,198	)
Goodwill and other intangibles		(44,185	)		(37,936	)
Other		(21,737	)		(21,724	)
		(732,672	)		(667,749	)
	$	(669,808	)	$	(595,769	)

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, 2015, 2014 and 2013, is as follows (in thousands):

	2015			2014			2013
Balance at beginning of year	$	1,171		$	949		$	1,045
Additions based on tax positions related to the current year		339			470			239
Additions for tax positions of prior years		785			39			114
Reductions for tax positions of prior years		(337	)		(287	)		(413	)
Settlements		—			—			(36	)
Balance at end of year	$	1,958		$	1,171		$	949

Leases (Tables)

12 Months Ended

Dec. 31, 2015

Leases [Abstract]

Schedule of Rent Expense

Total rental expense for the years ended December 31, 2015, 2014 and 2013 was as follows (in thousands):

	2015		2014		2013
Rental expense:
Marine equipment — barges	$	14,092	$	19,780	$	20,841
Marine equipment — towing vessels		143,067		136,331		124,877
Other buildings and equipment		9,383		9,146		10,298
Rental expense	$	166,542	$	165,257	$	156,016

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, 2015 were as follows (in thousands):

	Land, Buildings		Marine Equipment
	And Equipment		Barges		Towing Vessels		Total
2016	$	7,654	$	11,751	$	100,124	$	119,529
2017		6,806		10,544		46,362		63,712
2018		6,166		8,843		20,732		35,741
2019		4,375		3,856		317		8,548
2020		3,570		2,239		—		5,809
Thereafter		13,519		—		—		13,519
	$	42,090	$	37,233	$	167,535	$	246,858

Stock Award Plans (Tables)

12 Months Ended

Dec. 31, 2015

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

Compensation Cost Breakdown in Statement of Earnings

	2015		2014		2013
Compensation cost	$	11,104	$	11,591	$	11,621
Income tax benefit	$	4,120	$	4,358	$	4,370

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, 2015, 2014 and 2013 were as follows:

	2015			2014			2013
Dividend yield	None			None			None
Average risk-free interest rate		1.3	%		2.0	%		1.1	%
Stock price volatility		33	%		33	%		34	%
Estimated option term		Six years			Six years or seven 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, 2015, 2014 and 2013:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2012		351,173		$	45.54
Granted		111,527		$	70.94
Exercised		(83,096	)	$	34.51
Canceled or expired		—		$	—
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

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, 2015:

		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		1.1	$	32.82				16,910	$	32.82
$	46.74		56,629		2.1	$	46.74				56,629	$	46.74
$	65.28 – $74.99		283,963		4.6	$	70.98				141,669	$	67.90
$	93.64 – $96.85		35,763		5.1	$	94.27				11,921	$	94.27
$	101.46 – $114.11		37,167		5.2	$	103.22				12,389	$	103.22
$	31.35 – $114.11		430,432		4.2	$	71.01	$	668,000		239,518	$	63.56	$	668,000

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, 2015, 2014 and 2013:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2012		418,128		$	45.39
Granted		139,971		$	69.85
Vested		(149,162	)	$	44.30
Forfeited		(9,659	)	$	61.20
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

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, 2015, 2014, and 2013:

	Outstanding Non- Qualified or Nonincentive Stock Awards			Weighted Average Exercise Price
Outstanding at December 31, 2012		345,938		$	45.84
Granted		54,958		$	75.17
Exercised		(80,574	)	$	46.75
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
Granted		—		$	—
Exercised		(77,905	)	$	47.65
Outstanding at December 31, 2015		220,429		$	64.37

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, 2015:

	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		30,000		1.9	$	33.60				30,000	$	33.60
$41.24 – $56.45		71,276		4.3	$	52.34				71,276	$	52.34
$61.89 – $62.48		41,153		6.5	$	62.34				41,153	$	62.34
$75.17 – $99.52		78,000		7.3	$	88.28				78,000	$	88.28
$29.60 – $99.52		220,429		5.4	$	64.37	$	775,000		220,429	$	64.37	$	775,000

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, 2015, 2014 and 2013:

	Unvested Restricted Stock Award Shares			Weighted Average Grant Date Fair Value Per Share
Nonvested balance at December 31, 2012		348		$	62.99
Granted		10,536		$	75.65
Vested		(10,500	)	$	75.23
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

Retirement Plans (Tables)

12 Months Ended

Dec. 31, 2015

Defined Benefit Plan Disclosure [Line Items]

Summary of Asset Allocation

As of December 31, 2015 and 2014, these assets were allocated among asset categories as follows:

Asset Category	2015			2014			Current Minimum, Target and Maximum Allocation Policy
U.S. equity securities		50	%		52	%		30% — 50%— 70	%
International equity securities		18	%		18	%		0% — 20%— 30	%
Debt securities		28	%		30	%		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
	2015			2014			2015			2014			2015			2014
Change in benefit obligation
Benefit obligation at beginning of year	$	315,075		$	249,960		$	1,637		$	1,529		$	1,264		$	2,307
Service cost		14,683			10,645			—			—			—			—
Interest cost		13,302			12,839			64			73			36			110
Actuarial loss (gain)		(39,474	)		66,640			(30	)		180			(321	)		(1,065	)
Gross benefits paid		(6,261	)		(25,009	)		(145	)		(145	)		(88	)		(88	)
Benefit obligation at end of year	$	297,325		$	315,075		$	1,526		$	1,637		$	891		$	1,264

Accumulated benefit obligation at end of year	$	238,775		$	241,592		$	1,526		$	1,637		$	—		$	—

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		4.5	%	4.1	%	4.5	%	4.1	%	4.5	%	4.1	%
Rate of compensation increase	Age-based table			4.25	%	—		—		—		—
Health care cost trend rate
Initial rate		—		—		—		—		6.5	%	7.0	%
Ultimate rate		—		—		—		—		5.0	%	5.0	%
Years to ultimate		—		—		—		—		2019		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	$	—	$	—	$	—	$	—	$	107		$	167
Decrease		—		—		—		—		(93	)		(141	)

Summary of Change in Plan Assets

Change in plan assets
Fair value of plan assets at beginning of year	$	242,275		$	254,523		$	—		$	—		$	—		$	—
Actual return on plan assets		(2,426	)		12,761			—			—			—			—
Employer contribution		10,000			—			145			145			88			88
Gross benefits paid		(6,261	)		(25,009	)		(145	)		(145	)		(88	)		(88	)
Fair value of plan assets at end of year	$	243,588		$	242,275		$	—		$	—		$	—		$	—

Summary of Funded Status at End of Year

													Other Postretirement Benefits
	Pension Benefits												Postretirement
	Pension Plan						SERP						Welfare Plan
	2015			2014			2015			2014			2015			2014
Funded status at end of year
Fair value of plan assets	$	243,588		$	242,275		$	—		$	—		$	—		$	—
Benefit obligations		297,325			315,075			1,526			1,637			891			1,264
Funded status and amount recognized at end of year	$	(53,737	)	$	(72,800	)	$	(1,526	)	$	(1,637	)	$	(891	)	$	(1,264	)

Amounts Recognized in the Consolidated Balance Sheets

Amounts recognized in the consolidated balance sheets
Noncurrent asset	$	—		$	—		$	—		$	—		$	—		$	—
Current liability		—			—			(149	)		(141	)		(68	)		(83	)
Long-term liability		(53,737	)		(72,800	)		(1,377	)		(1,496	)		(823	)		(1,181	)

Amounts Recognized in Accumulated Other Comprehensive Income

Amounts recognized in accumulated other comprehensive income
Net actuarial loss (gain)	$	77,940	$	104,795	$	508	$	566	$	(6,319	)	$	(6,787	)
Prior service cost (credit)		—		—		—		—		—			—
Accumulated other compensation income	$	77,940	$	104,795	$	508	$	566	$	(6,319	)	$	(6,787	)

Projected Benefit Obligation in Excess of Plan Assets

	Pension Benefits
	Pension Plan						SERP
	2015			2014			2015			2014
Projected benefit obligation in excess of plan assets
Projected benefit obligation at end of year		$	297,325		$	315,075		$	1,526		$	1,637
Fair value of plan assets at end of year			243,588			242,275			—			—

Accumulated Benefit Obligation in Excess of Plan Assets

	Pension Benefits
	Pension Plan						SERP
	2015			2014			2015			2014
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation at end of year		$	—		$	—		$	1,526		$	1,637
Accumulated benefit obligation at end of year			—			—			1,526			1,637
Fair value of plan assets at end of year			—			—			—			—

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, 2015 and 2014 (in thousands):

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2015		2014		2015		2014		2015		2014
Expected employer contributions
First year	$	—	$	8,400	$	152	$	143	$	70	$	84

Expected Benefit Payments

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2015		2014		2015		2014		2015		2014
Expected benefit payments (gross)
Year one	$	7,678	$	7,100	$	152	$	143	$	81	$	96
Year two		8,298		7,672		157		151		86		98
Year three		9,013		8,333		154		155		86		103
Year four		9,748		9,080		152		153		86		95
Year five		10,415		9,868		149		150		85		94
Next five years		63,860		62,666		608		621		341		445

Summary of Expected Federal Subsidy

									Other Postretirement Benefits
	Pension Benefits								Postretirement
	Pension Plan				SERP				Welfare Plan
	2015		2014		2015		2014		2015			2014
Expected federal subsidy
Year one	$	—	$	—	$	—	$	—	$	(11	)	$	(11	)
Year two		—		—		—		—		(11	)		(11	)
Year three		—		—		—		—		(11	)		(11	)
Year four		—		—		—		—		(12	)		(12	)
Year five		—		—		—		—		(12	)		(12	)
Next five years		—		—		—		—		(55	)		(55	)

Pension Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Components of Net Periodic Benefit Cost

	Pension Benefits
	Pension Plan									SERP
	2015			2014			2013			2015			2014			2013
Components of net periodic benefit cost
Service cost	$	14,683		$	10,645		$	12,824		$	—		$	—		$	—
Interest cost		13,302			12,839			11,400			64			73			70
Expected return on plan assets		(17,921	)		(18,858	)		(16,127	)		—			—			—
Amortization:
Actuarial loss		7,728			701			8,276			28			16			19
Prior service credit		—			—			—			—			—			—
Net periodic benefit cost		17,792			5,327			16,373			92			89			89

Other changes in plan assets and benefit obligations recognized in other comprehensive income
Current year actuarial loss (gain)		(19,127	)		72,737			(61,759	)		(30	)		180			(138	)
Recognition of actuarial loss		(7,728	)		(701	)		(8,276	)		(28	)		(16	)		(19	)
Recognition of prior service credit		—			—			—			—			—			—
Total recognized in other comprehensive income		(26,855	)		72,036			(70,035	)		(58	)		164			(157	)

Total recognized in net periodic benefit cost and other comprehensive income	$	(9,063	)	$	77,363		$	(53,662	)	$	34		$	253		$	(68	)

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	4.1	%	5.0	%	4.1	%	4.1	%	5.0	%	4.1	%
Expected long-term rate of return on plan assets	7.5	%	7.5	%	7.5	%	—		—		—
Rate of compensation increase	4.25	%	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 2016 are as follows (in thousands):

	Pension Benefits
	Pension Plan		SERP
Actuarial loss	$	4,924	$	26
Prior service credit		—		—
	$	4,924	$	26

Other Postretirement Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Components of Net Periodic Benefit Cost

	Other Postretirement Benefits
	Postretirement Welfare Plan
	2015			2014			2013
Components of net periodic benefit cost
Service cost	$	—		$	—		$	—
Interest cost		36			110			112
Amortization:
Actuarial gain		(793	)		(649	)		(620	)
Prior service cost		—			—			—
Net periodic benefit cost		(757	)		(539	)		(508	)

Other changes in benefit obligations recognized in other comprehensive income
Current year actuarial gain		(322	)		(1,065	)		(600	)
Recognition of actuarial gain		793			649			620
Recognition of prior service cost		—			—			—
Adjustment for actual Medicare Part D reimbursement		(3	)		(8	)		(5	)
Total recognized in other comprehensive income		468			(424	)		15

Total recognized in net periodic benefit cost and other comprehensive income	$	(289	)	$	(963	)	$	(493	)

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	4.1	%	5.0	%	4.1	%
Health care cost trend rate:
Initial rate	7.0	%	7.0	%	7.5	%
Ultimate rate	5.0	%	5.0	%	5.0	%
Years to ultimate	2019		2018		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	$	5		$	7		$	10
Decrease		(4	)		(6	)		(9	)

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 2016 are as follows (in thousands):

	Other Postretirement Benefits
	Postretirement Welfare Plan
Actuarial gain	$	(745	)
Prior service cost		—
	$	(745	)

Other Comprehensive Income (Tables)

12 Months Ended

Dec. 31, 2015

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, 2015, 2014 and 2013 were as follows (in thousands):

	2015							2014									2013
	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	$	6,963	$	(2,667	)	$	4,296	$	68		$	(26	)	$	42		$	7,675		$	(2,942	)	$	4,733
Actuarial gains (losses)		19,482		(7,456	)		12,026		(71,843	)		27,507			(44,336	)		62,503			(23,962	)		38,541

Foreign currency translation adjustments		29		—			29		(35	)		—			(35	)		108			—			108

Change in fair value of derivative instruments (b):
Unrealized gains (losses)		—		—			—		24			(9	)		15			2,851			(996	)		1,855
Reclassified to net earnings		—		—			—		121			(51	)		70			(1,389	)		486			(903	)
Total	$	26,474	$	(10,123	)	$	16,351	$	(71,665	)	$	27,421		$	(44,244	)	$	71,748		$	(27,414	)	$	44,334

(a)	Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate. (See Note 8 – 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, 2015

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, 2015, 2014 and 2013 (in thousands, except per share amounts):

	2015			2014			2013
Net earnings attributable to Kirby	$	226,684		$	282,006		$	253,061
Undistributed earnings allocated to restricted shares		(1,345	)		(1,643	)		(1,819	)
Income available to Kirby common stockholders — basic		225,339			280,363			251,242
Undistributed earnings allocated to restricted shares		1,345			1,643			1,819
Undistributed earnings reallocated to restricted shares		(1,343	)		(1,637	)		(1,813	)
Income available to Kirby common stockholders — diluted	$	225,341		$	280,369		$	251,248

Shares outstanding:
Weighted average common stock issued and outstanding		55,056			57,006			56,762
Weighted average unvested restricted stock		(327	)		(332	)		(408	)
Weighted average common stock outstanding — basic		54,729			56,674			56,354
Dilutive effect of stock options		97			193			198
Weighted average common stock outstanding — diluted		54,826			56,867			56,552
Net earnings per share attributable to Kirby common stockholders:
Basic	$	4.12		$	4.95		$	4.46

Diluted	$	4.11		$	4.93		$	4.44

Quarterly Results (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly Results (Unaudited) [Abstract]

Schedule of Quarterly Results

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

The unaudited quarterly results for the year ended December 31, 2014 were as follows (in thousands, except per share amounts):

	Three Months Ended
	March 31, 2014			June 30, 2014			September 30, 2014			December 31, 2014
Revenues	$	589,246		$	628,054		$	680,721		$	668,297
Costs and expenses		482,443			501,556			552,642			554,646
Gain on disposition of assets		51			527			47			156
Operating income		106,854			127,025			128,126			113,807
Other income (expense)		(236	)		123			27			125
Interest expense		(5,618	)		(5,469	)		(5,225	)		(5,149	)
Earnings before taxes on income		101,000			121,679			122,928			108,783
Provision for taxes on income		(37,989	)		(45,768	)		(45,715	)		(40,310	)
Net earnings		63,011			75,911			77,213			68,473
Less: Net earnings attributable to noncontrolling interests		(765	)		(919	)		(496	)		(422	)
Net earnings attributable to Kirby	$	62,246		$	74,992		$	76,717		$	68,051

Net earnings per share attributable to Kirby common stockholders:
Basic	$	1.09		$	1.32		$	1.34		$	1.19
Diluted	$	1.09		$	1.31		$	1.34		$	1.19

Segment Data (Tables)

12 Months Ended

Dec. 31, 2015

Segment Data [Abstract]

Schedule of Segment Reporting Information, by Segment

	2015			2014			2013
Revenues:
Marine transportation	$	1,663,090		$	1,770,684		$	1,713,167
Diesel engine services		484,442			795,634			529,028
	$	2,147,532		$	2,566,318		$	2,242,195
Segment profit (loss):
Marine transportation	$	374,842		$	429,864		$	408,255
Diesel engine services		18,921			60,063			42,767
Other		(32,051	)		(35,537	)		(42,344	)
	$	361,712		$	454,390		$	408,678
Total assets:
Marine transportation	$	3,451,553		$	3,317,696		$	3,046,692
Diesel engine services		637,549			736,129			576,472
Other		67,164			88,084			59,353
	$	4,156,266		$	4,141,909		$	3,682,517
Depreciation and amortization:
Marine transportation	$	175,798		$	154,019		$	149,574
Diesel engine services		12,498			11,463			11,096
Other		3,944			3,830			3,767
	$	192,240		$	169,312		$	164,437
Capital expenditures:
Marine transportation	$	311,862		$	340,315		$	237,964
Diesel engine services		28,907			7,486			4,658
Other		4,706			7,343			10,605
	$	345,475		$	355,144		$	253,227

Schedule of Other Segment Reporting Information

The following table presents the details of “Other” segment profit (loss) for the years ended December 31, 2015, 2014 and 2013 (in thousands):

	2015			2014			2013
General corporate expenses	$	(14,773	)	$	(14,896	)	$	(15,728	)
Interest expense		(18,738	)		(21,461	)		(27,872	)
Gain on disposition of assets		1,672			781			888
Other income (expense)		(212	)		39			368
	$	(32,051	)	$	(35,537	)	$	(42,344	)

The following table presents the details of “Other” total assets as of December 31, 2015, 2014 and 2013 (in thousands):

	2015		2014		2013
General corporate assets	$	65,074	$	85,545	$	57,197
Investment in affiliates		2,090		2,539		2,156
	$	67,164	$	88,084	$	59,353

Summary of Significant Accounting Policies (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Significant Accounting Policies [Line Items]
Limited partnership ownership	50.00%
Accruals for revenues earned included in accounts receivable	$ 90,166,000	$ 143,615,000
Period in which recertification of ocean going vessels occur twice	5 years
Receivables from insurance companies to cover claims in excess included in accounts receivable	$ 77,684,000	92,379,000
Interest expense excludes capitalized interest	3,026,000	639,000	$ 0
Impairment of goodwill	0	0
Gross carrying value of goodwill	604,185,000	608,872,000
Accumulated amortization	15,566,000	15,566,000
Accumulated impairment losses	1,901,000	1,901,000
Net goodwill	586,718,000	591,405,000
Recognized amortization of major maintenance costs	22,126,000	16,409,000	9,029,000
Accrued insurance liabilities	$ 23,737,000	25,416,000	$ 22,971,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Other investments ownership percentage	20.00%
Period of amortization of shipyard costs	30 months
Maximum [Member]
Significant Accounting Policies [Line Items]
Other investments ownership percentage	50.00%
Period of amortization of shipyard costs	60 months
Buildings [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	10 years
Buildings [Member] \| Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	40 years
Other Equipment [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	2 years
Other Equipment [Member] \| Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	10 years
Marine Transportation Equipment [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	5 years
Marine Transportation Equipment [Member] \| Maximum [Member]
Significant Accounting Policies [Line Items]
Estimated useful lives of the individual assets	40 years
Marine Transportation Segment [Member]
Significant Accounting Policies [Line Items]
Net goodwill	$ 381,243,000	381,243,000
Range of term contracts	1 year
Marine Transportation Segment [Member] \| Minimum [Member]
Significant Accounting Policies [Line Items]
Range of term contracts	1 year
Marine Transportation Segment [Member] \| Maximum [Member]
Significant Accounting Policies [Line Items]
Range of term contracts	3 years
Diesel Engine Services Segment [Member]
Significant Accounting Policies [Line Items]
Net goodwill	$ 205,475,000	$ 210,162,000

Inventories (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Details of inventories [Abstract]
Finished goods	$ 163,501	$ 179,760
Work in process	21,010	12,594
Total inventory, net	$ 184,511	$ 192,354

Long-Term Debt (Details) - USD ($)	12 Months Ended
Long-Term Debt (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Line of credit, increase in aggregate commitments	$ 300,000,000
Senior Notes	500,000,000
Total debt outstanding, Fair value	768,766,000	$ 705,215,000
Revolving Credit Facility Due November 9, 2015 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 0	116,700,000
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
Term Loan Due July 1, 2016 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 0	$ 100,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Term loan, duration	5 years
Term Loan [Member] \| LIBOR [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	LIBOR
Basis spread on variable rate	1.50%
Term Loan [Member] \| Alternate Base Rate [Member]
Debt Instrument [Line Items]
Interest rate, variable rate basis	Alternate Base Rate
Basis spread on variable rate	0.50%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Average borrowing under revolving credit facility	$ 293,451,000
Commitment amount	$ 25,000,000
Commitment fee	0.10%
Weighted average interest rate	1.30%
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	$ 931,000
Line Of Credit [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 5,047,000

Long-Term Debt, Schedule of Long-Term Debt (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term Debt	$ 778,834,000	$ 716,700,000
Revolving Credit Facility Due April 30, 2020 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 278,834,000	0
Credit facility, expiration date	Apr. 30, 2020
Long term debt, face amount	$ 550,000,000
Revolving Credit Facility Due November 9, 2015 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 0	116,700,000
Credit facility, expiration date	Nov. 09, 2015
Long term debt, face amount	$ 325,000,000
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
Term Loan Due July 1, 2016 [Member]
Debt Instrument [Line Items]
Credit facility, amount outstanding	$ 0	100,000,000
Credit facility, expiration date	Jul. 01, 2016
Long term debt, face amount	$ 540,000,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long term debt, face amount		$ 325,000,000

Long-Term Debt, Schedule of Aggregate Payments Due on The Long-Term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Long-Term Debt [Abstract]
2016	$ 0
2017	0
2018	0
2019	0
2020	428,834
Thereafter	350,000
Long-term Debt	$ 778,834	$ 716,700

Taxes on Income, Earnings Before Taxes (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Taxes on Income [Abstract]
Earnings before taxes on income - United States	$ 80,115,000	$ 90,623,000	$ 93,072,000	$ 97,902,000	$ 108,783,000	$ 122,928,000	$ 121,679,000	$ 101,000,000	$ 361,712,000	$ 454,390,000	$ 408,678,000
Federal [Abstract]
Current									64,707,000	81,953,000	41,008,000
Deferred									59,582,000	72,920,000	97,586,000
State and local									9,453,000	14,909,000	13,785,000
Total provision for taxes on income	$ 29,043,000	$ 33,512,000	$ 34,696,000	$ 36,491,000	$ 40,310,000	$ 45,715,000	$ 45,768,000	$ 37,989,000	133,742,000	169,782,000	152,379,000
Tax benefit realized from equity compensation plans									$ 964,000	$ 6,119,000	$ 3,001,000

Taxes on Income, Schedule of Effective Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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	1.70%	2.20%	2.20%
Other - net	0.30%	0.20%	0.10%
Effective income tax rate	37.00%	37.40%	37.30%

Taxes on Income, Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Current deferred tax assets [Abstract]
Compensated absences	$ 829,000	$ 854,000
Allowance for doubtful accounts	3,288,000	3,111,000
Insurance accruals	4,234,000	2,858,000
Other	3,372,000	3,739,000
Current deferred tax assets, Total	11,723,000	10,562,000
Deferred tax assets [Abstract]
Postretirement health care benefits	2,501,000	2,795,000
Insurance accruals	3,410,000	3,325,000
Deferred compensation	10,534,000	10,157,000
Unrealized loss on defined benefit plans	25,245,000	34,501,000
Operating loss carryforwards	5,188,000	5,219,000
Other	20,702,000	20,687,000
Valuation allowances	(4,716,000)	(4,704,000)
Deferred tax assets	62,864,000	71,980,000
Deferred tax liabilities [Abstract]
Property	(604,737,000)	(547,388,000)
Deferred state taxes	(53,542,000)	(49,503,000)
Pension benefits	(8,471,000)	(11,198,000)
Goodwill and other intangibles	(44,185,000)	(37,936,000)
Other	(21,737,000)	(21,724,000)
Deferred tax liabilities	(732,672,000)	(667,749,000)
Deferred tax assets (liabilities)	(669,808,000)	$ (595,769,000)
Operating loss carryforwards, net of valuation allowance	$ 472,000
Expiration dates, operating loss carryforwards	Dec. 31, 2030
Unrecognized tax benefits including interest and penalties	$ 2,479,000
Amount that would impact the effective tax rate, if recognized	$ 1,678,000
Minimum [Member] \| State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2009
Minimum [Member] \| Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2012
Maximum [Member] \| State and Local Jurisdiction [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2014
Maximum [Member] \| Internal Revenue Service (IRS) [Member]
Income Tax Examination [Line Items]
Years open to audit under the statute of limitations	2014

Taxes on Income, Reconciliation of Liability for Unrecognized Tax Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of the beginning and ending amount of the liability for unrecognized tax benefits [Roll Forward]
Balance at beginning of year	$ 1,171,000	$ 949,000	$ 1,045,000
Additions based on tax positions related to the current year	339,000	470,000	239,000
Additions for tax positions of prior years	785,000	39,000	114,000
Reductions for tax positions of prior years	(337,000)	(287,000)	(413,000)
Settlements	0	0	(36,000)
Balance at end of year	1,958,000	1,171,000	949,000
Income tax penalties and interest recognized	216,000	40,000	(421,000)
Accrued liabilities for payment of interest and penalties	$ 522,000	$ 306,000	$ 266,000

Leases, Schedule of Rent Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	$ 166,542	$ 165,257	$ 156,016
Other Buildings and Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	9,383	9,146	10,298
Tank Barges [Member] \| Marine Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	14,092	19,780	20,841
Towing Vessels [Member] \| Marine Equipment [Member]
Property Subject To Or Available for Operating Lease [Line Items]
Rental expense	$ 143,067	$ 136,331	$ 124,877
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, 2015 USD ($)
Operating Leased Assets [Line Items]
2016	$ 119,529
2017	63,712
2018	35,741
2019	8,548
2020	5,809
Thereafter	13,519
Future minimum lease payments under operating leases	246,858
Marine Equipment [Member] \| Tank Barges [Member]
Operating Leased Assets [Line Items]
2016	11,751
2017	10,544
2018	8,843
2019	3,856
2020	2,239
Thereafter	0
Future minimum lease payments under operating leases	37,233
Marine Equipment [Member] \| Towing Vessels [Member]
Operating Leased Assets [Line Items]
2016	100,124
2017	46,362
2018	20,732
2019	317
2020	0
Thereafter	0
Future minimum lease payments under operating leases	167,535
Land Buildings and Equipment [Member]
Operating Leased Assets [Line Items]
2016	7,654
2017	6,806
2018	6,166
2019	4,375
2020	3,570
Thereafter	13,519
Future minimum lease payments under operating leases	$ 42,090

Stock Award Plans (Details) - USD ($)	12 Months Ended
Stock Award Plans (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Stock Award Plans [Abstract]
Compensation cost	$ 11,104,000	$ 11,591,000	$ 11,621,000
Income tax benefit	$ 4,120,000	4,358,000	4,370,000
Stock Award Plan Information [Abstract]
Term of grant	7 years
Vesting period	3 years
Share-based Compensation Plans Combined Disclosure [Abstract]
Intrinsic value of stock options exercised	$ 2,555,000	11,671,000	6,703,000
Tax benefit from stock options exercised	948,000	4,388,000	2,520,000
Intrinsic value of restricted stock vestings	10,270,000	14,847,000	10,993,000
Tax benefit from restricted stock vesting	3,810,000	5,583,000	4,133,000
Fair value of options vested	2,180,000	3,759,000	3,341,000
Fair value of restricted stock vested	$ 10,270,000	$ 14,847,000	$ 10,993,000
Fair value of stock options granted (in dollars per share)	$ 25.18	$ 36.05	$ 25.14
Fair value of stock options granted	$ 2,893,000	$ 4,226,000	$ 4,184,000
Employee Stock Award Plan [Member]
Stock Award Plan Information [Abstract]
Shares available for future grants (in shares)	2,329,238
Options Exercisable [Abstract]
Stock options exercisable (in shares)	239,518	157,140	175,170
Unvested Restricted Stock Award Shares [Roll Forward]
Nonvested balance beginning of period, Unvested Restricted Stock Award Shares (in shares)	321,453	399,278	418,128
Granted, Unvested Restricted Stock Award Shares (in shares)	122,740	97,706	139,971
Vested, Unvested Restricted Stock Award Shares (in shares)	(113,958)	(141,870)	(149,162)
Forfeited, Unvested Restricted Stock Award Shares (in shares)	(18,508)	(33,661)	(9,659)
Nonvested balance end of period, Unvested Restricted Stock Award Shares (in shares)	311,727	321,453	399,278
Weighted Average Grant Date Fair Value Per Share [Abstract]
Nonvested balance end of period, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$ 71.04	$ 54.92	$ 45.39
Granted, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	75.04	97.46	69.85
Vested, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	60.73	45.64	44.30
Forfeited, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	82.00	63.56	61.20
Nonvested balance end of period, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	75.73	$ 71.04	$ 54.92
Employee Stock Award Plan [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 year 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] \| Second Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	$ 46.74
Options Outstanding [Abstract]
Number Outstanding (in shares)	56,629
Weighted Average Remaining Contractual Life	2 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 46.74
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] \| 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)	$ 65.28
Options Outstanding [Abstract]
Number Outstanding (in shares)	283,963
Weighted Average Remaining Contractual Life	4 years 7 months 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 70.98
Options Exercisable [Abstract]
Number Exercisable (in shares)	141,669
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 67.90
Employee Stock Award Plan [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)	35,763
Weighted Average Remaining Contractual Life	5 years 1 month 6 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 94.27
Options Exercisable [Abstract]
Number Exercisable (in shares)	11,921
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 94.27
Employee Stock Award Plan [Member] \| Fifth Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	114.11
Range of Exercise Prices, lower limit (in dollars per share)	$ 101.46
Options Outstanding [Abstract]
Number Outstanding (in shares)	37,167
Weighted Average Remaining Contractual Life	5 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 103.22
Options Exercisable [Abstract]
Number Exercisable (in shares)	12,389
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 103.22
Employee Stock Award Plan [Member] \| Full Exercise Price Range [Member]
Outstanding and Exercisable Stock options [Abstract]
Range of Exercise Prices, upper limit (in dollars per share)	114.11
Range of Exercise Prices, lower limit (in dollars per share)	$ 31.35
Options Outstanding [Abstract]
Number Outstanding (in shares)	430,432
Weighted Average Remaining Contractual Life	4 years 2 months 12 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 71.01
Aggregate Intrinsic Value, Options Outstanding	$ 668,000
Options Exercisable [Abstract]
Number Exercisable (in shares)	239,518
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 63.56
Aggregate Intrinsic Value, Options Exercisable	$ 668,000
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)	539,531
Options Exercisable [Abstract]
Stock options exercisable (in shares)	220,429	298,334	320,082
Unvested Restricted Stock Award Shares [Roll Forward]
Nonvested balance beginning of period, Unvested Restricted Stock Award Shares (in shares)	292	384	348
Granted, Unvested Restricted Stock Award Shares (in shares)	20,350	8,160	10,536
Vested, Unvested Restricted Stock Award Shares (in shares)	(18,851)	(8,252)	(10,500)
Nonvested balance end of period, Unvested Restricted Stock Award Shares (in shares)	1,791	292	384
Weighted Average Grant Date Fair Value Per Share [Abstract]
Nonvested balance end of period, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	$ 99.52	$ 75.65	$ 62.99
Granted, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	78.52	99.52	75.65
Vested, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	79.77	98.41	75.23
Nonvested balance end of period, Weighted Average Grant Date Fair Value Per Share (in dollars per share)	68.73	$ 99.52	$ 75.65
2000 Director Plan [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)	30,000
Weighted Average Remaining Contractual Life	1 year 10 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 33.60
Options Exercisable [Abstract]
Number Exercisable (in shares)	30,000
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 33.60
2000 Director Plan [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	4 years 3 months 18 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] \| 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	6 years 6 months
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] \| 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)	78,000
Weighted Average Remaining Contractual Life	7 years 3 months 18 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 88.28
Options Exercisable [Abstract]
Number Exercisable (in shares)	78,000
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 88.28
2000 Director Plan [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] \| Full Exercise Price Range [Member]
Options Outstanding [Abstract]
Number Outstanding (in shares)	220,429
Weighted Average Remaining Contractual Life	5 years 4 months 24 days
Weighted Average Exercise Price, Options Outstanding (in dollars per share)	$ 64.37
Aggregate Intrinsic Value, Options Outstanding	$ 775,000
Options Exercisable [Abstract]
Number Exercisable (in shares)	220,429
Weighted Average Exercise Price, Options Exercisable (in dollars per share)	$ 64.37
Aggregate Intrinsic Value, Options Exercisable	$ 775,000
Stock Options [Member]
Share-based Compensation Plans Combined Disclosure [Abstract]
Unrecognized compensation cost related to unvested awards	$ 2,956,000
Weighted average period of recognition in years	1 year 2 months 12 days
Fair Value Assumptions [Abstract]
Dividend yield	0.00%	0.00%	0.00%
Average risk-free interest rate	1.30%	2.00%	1.10%
Stock price volatility	33.00%	33.00%	34.00%
Estimated option term	6 years
Stock Options [Member] \| Minimum [Member]
Fair Value Assumptions [Abstract]
Estimated option term		6 years	6 years
Stock Options [Member] \| Maximum [Member]
Fair Value Assumptions [Abstract]
Estimated option term		7 years	7 years
Stock Options [Member] \| Employee Stock Award Plan [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	322,956	379,604	351,173
Granted, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	114,894	75,204	111,527
Exercised, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	0	(119,276)	(83,096)
Canceled or expired, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	(7,418)	(12,576)	0
Outstanding at Period End, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	430,432	322,956	379,604
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start, Weighted Average Exercise Price (in dollars per share)	$ 69.95	$ 55.42	$ 45.54
Granted, Weighted Average Exercise Price (in dollars per share)	74.99	98.91	70.94
Exercised, Weighted Average Exercise Price (in dollars per share)	0	42.07	34.51
Canceled or expired, Weighted Average Exercise Price (in dollars per share)	86.28	68.89	0
Outstanding at Period End, Weighted Average Exercise Price (in dollars per share)	$ 71.01	$ 69.95	$ 55.42
Stock Options [Member] \| 2000 Director Plan [Member]
Outstanding Non-Qualified or Nonincentive Stock Awards [Roll Forward]
Outstanding at Period Start, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	298,334	320,322	345,938
Granted, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	0	42,000	54,958
Exercised, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	(77,905)	(63,988)	(80,574)
Outstanding at Period End, Outstanding Non-Qualified or Nonincentive Stock Awards (in shares)	220,429	298,334	320,322
Weighted Average Exercise Price [Abstract]
Outstanding at Period Start, Weighted Average Exercise Price (in dollars per share)	$ 60.01	$ 50.64	$ 45.84
Granted, Weighted Average Exercise Price (in dollars per share)	0	99.52	75.17
Exercised, Weighted Average Exercise Price (in dollars per share)	47.65	39.08	46.75
Outstanding at Period End, Weighted Average Exercise Price (in dollars per share)	$ 64.37	$ 60.01	$ 50.64
Restricted Stock [Member]
Share-based Compensation Plans Combined Disclosure [Abstract]
Unrecognized compensation cost related to unvested awards	$ 16,920,000
Weighted average period of recognition in years	2 years 9 months 18 days

Retirement Plans (Details) - USD ($)	12 Months Ended
Retirement Plans (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]
Expected long-term rate of return on plan assets	7.50%	7.50%
Contribution percentage to defined contribution plan	102.00%
Pension plan defined benefit plan cost increase limit percentage	4.00%
Aggregate contributions to the plans	$ 24,077,000	$ 23,356,000	$ 23,158,000
Seafarers Pension Trust [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension contributions	$ 1,202,000	$ 1,290,000
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, 2015	Dec. 31, 2014
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	50.00%	52.00%
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	18.00%	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	28.00%	30.00%
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	4.00%	0.00%
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, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	$ 315,075	$ 249,960
Service cost	14,683	10,645	$ 12,824
Interest cost	13,302	12,839	11,400
Actuarial loss (gain)	(39,474)	66,640
Gross benefits paid	(6,261)	(25,009)
Benefit obligation at end of year	297,325	315,075	249,960
Accumulated benefit obligation at end of year	238,775	241,592
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	1,637	1,529
Service cost	0	0	0
Interest cost	64	73	70
Actuarial loss (gain)	(30)	180
Gross benefits paid	(145)	(145)
Benefit obligation at end of year	1,526	1,637	1,529
Accumulated benefit obligation at end of year	1,526	1,637
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Benefit obligation at beginning of year	1,264	2,307
Service cost	0	0	0
Interest cost	36	110	112
Actuarial loss (gain)	(321)	(1,065)
Gross benefits paid	(88)	(88)
Benefit obligation at end of year	891	1,264	$ 2,307
Accumulated benefit obligation at end of year	$ 0	$ 0

Retirement Plans, Weighted-Average Assumption Used to Determine Benefit Obligation (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.50%	4.10%
Rate of compensation increase		4.25%
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	4.50%	4.10%
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	4.50%	4.10%
Rate of compensation increase	0.00%	0.00%
Health care cost trend rate [Abstract]
Initial rate	6.50%	7.00%
Ultimate rate	5.00%	5.00%
Years to ultimate	2019	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, 2015	Dec. 31, 2014	Dec. 31, 2013
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	107	167
Effect of one-percentage-point change in assumed health care cost trend rate on postretirement obligation, Decrease	(93)	(141)
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost, Increase	5	7	$ 10
Effect of one-percentage-point change in assumed health care cost trend rate on aggregate service and interest cost, Decrease	$ (4)	$ (6)	$ (9)

Retirement Plans, Summary of Change in Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets at beginning of year	$ 242,275	$ 254,523
Actual return on plan assets	(2,426)	12,761
Employer contribution	10,000	0
Gross benefits paid	(6,261)	(25,009)
Fair value of plan assets at end of year	243,588	242,275
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	145	145
Gross benefits paid	(145)	(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	88	88
Gross benefits paid	(88)	(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, 2015	Dec. 31, 2014	Dec. 31, 2013
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 243,588	$ 242,275	$ 254,523
Benefit obligations	297,325	315,075	249,960
Funded status and amount recognized at end of year	(53,737)	(72,800)
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Benefit obligations	1,526	1,637	1,529
Funded status and amount recognized at end of year	(1,526)	(1,637)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0	0
Benefit obligations	891	1,264	$ 2,307
Funded status and amount recognized at end of year	$ (891)	$ (1,264)

Retirement Plans, Amounts Recognized in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	$ 0	$ 0
Current liability	0	0
Long-term liability	(53,737)	(72,800)
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	0	0
Current liability	(149)	(141)
Long-term liability	(1,377)	(1,496)
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Noncurrent asset	0	0
Current liability	(68)	(83)
Long-term liability	$ (823)	$ (1,181)

Retirement Plans, Amounts Recognized in Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	$ 77,940	$ 104,795
Prior service cost (credit)	0	0
Accumulated other compensation income	77,940	104,795
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	508	566
Prior service cost (credit)	0	0
Accumulated other compensation income	508	566
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss (gain)	(6,319)	(6,787)
Prior service cost (credit)	0	0
Accumulated other compensation income	$ (6,319)	$ (6,787)

Retirement Plans, Projected Benefit Obligation in Excess of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 297,325	$ 315,075
Fair value of plan assets at end of year	243,588	242,275
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	1,526	1,637
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, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	$ 0	$ 0
Accumulated benefit obligation at end of year	0	0
Fair value of plan assets at end of year	0	0
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation at end of year	1,526	1,637
Accumulated benefit obligation at end of year	1,526	1,637
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, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	$ 0	$ 8,400
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	152	143
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected employer contributions	$ 70	$ 84

Retirement Plans, Expected Benefit Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	$ 7,678	$ 7,100
Year two	8,298	7,672
Year three	9,013	8,333
Year four	9,748	9,080
Year five	10,415	9,868
Next five years	63,860	62,666
SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	152	143
Year two	157	151
Year three	154	155
Year four	152	153
Year five	149	150
Next five years	608	621
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Year one	81	96
Year two	86	98
Year three	86	103
Year four	86	95
Year five	85	94
Next five years	$ 341	$ 445

Retirement Plans, Summary of Expected Federal Subsidy (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
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	(11)	(11)
Year two	(11)	(11)
Year three	(11)	(11)
Year four	(12)	(12)
Year five	(12)	(12)
Next five years	$ (55)	$ (55)

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

12 Months Ended

Dec. 31, 2015

Dec. 31, 2014

Dec. 31, 2013

Defined Benefit Plan Disclosure [Line Items]

Recognition of actuarial loss (gain)

^[1]

$ (19,482)

$ 71,843

$ (62,503)

Recognition of prior service credit (cost)

^[1]

(6,963)

(68)

(7,675)

Pension Benefits [Member]

Defined Benefit Plan Disclosure [Line Items]

Service cost

14,683

10,645

12,824

Interest cost

13,302

12,839

11,400

Expected return on plan assets

(17,921)

(18,858)

(16,127)

Actuarial loss (gain)

7,728

701

8,276

Prior service (credit) cost

Net periodic benefit cost

17,792

5,327

16,373

Current year actuarial loss (gain)

(19,127)

72,737

(61,759)

Recognition of actuarial loss (gain)

(7,728)

(701)

(8,276)

Recognition of prior service credit (cost)

Total recognized in other comprehensive income

(26,855)

72,036

(70,035)

Total recognized in net periodic benefit cost and other comprehensive income

(9,063)

77,363

(53,662)

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

(138)

Recognition of actuarial loss (gain)

(28)

(16)

(19)

Recognition of prior service credit (cost)

Total recognized in other comprehensive income

(58)

164

(157)

Total recognized in net periodic benefit cost and other comprehensive income

253

(68)

Contingencies and Commitments (Details)	12 Months Ended
Contingencies and Commitments (Details)	Dec. 31, 2015 USD ($) PotentiallyResponsibleParty Individual Spill Segment	Dec. 31, 2014 Segment	Dec. 31, 2013 Segment
Certain Significant Risks and Uncertainties [Abstract]
Customer relationship period	40 years
Number of single customers accounting more than 10% of segment revenue \| Segment	0	0	0
Percentage of customers revenue	10.00%	10.00%	10.00%
Segment operates authorized distributors \| Segment	17
Diesel engine services segment's relationship	50 years
Guarantor Obligations [Line Items]
Issued guaranties \| $	$ 19,968,000
Guarantor Obligations, Term	All of these instruments have an expiration date within four years.
Performance Bonds [Member]
Guarantor Obligations [Line Items]
Issued guaranties \| $	$ 13,669,000
Standby Letters of Credit [Member]
Guarantor Obligations [Line Items]
Issued guaranties \| $	$ 6,299,000
Gulfco Marine Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs")	3
Number of companies named as Potentially Responsible Parties ("PRPs")	4
EPA incurred cleanup expense \| $	$ 9,943,000
EPA oversight costs \| $	$ 2,258,000
Number of defendants seeking contribution and indemnity under CERCLA \| Individual	21
Portland Harbor Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs")	250
Number of spills \| Spill	4
Palmer Barge Line Superfund Site [Member]
Site Contingency [Line Items]
Number of other companies also named as Potentially Responsible Parties ("PRPs")	45
Number of other companies also in an investigation and feasibility study agreement with EPA	3
Number of new companies in an agreement with the EPA	5
Number of Potentially Responsible Parties notified by EPA of intent to recover costs	30
EPA notification intent to recover costs incurred \| $	$ 2,949,000
Marine Transportation's [Member]
Certain Significant Risks and Uncertainties [Abstract]
Percentage of inland revenue	80.00%
Percentage of costal revenue	80.00%
Number of single customers accounting more than 10% of segment revenue \| Segment	0	0	0
Marine Transportation's [Member] \| Minimum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts	1 year
Marine Transportation's [Member] \| Maximum [Member]
Certain Significant Risks and Uncertainties [Abstract]
Range of renewal options under term contracts	3 years

Segment Data (Details)	3 Months Ended								12 Months Ended
Segment Data (Details)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) Segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Data [Abstract]
Number of Reportable Segments \| Segment									2
Revenues [Abstract]
Marine transportation									$ 1,663,090,000	$ 1,770,684,000	$ 1,713,167,000
Diesel engine services									484,442,000	795,634,000	529,028,000
Total revenues	$ 484,138,000	$ 532,565,000	$ 543,156,000	$ 587,673,000	$ 668,297,000	$ 680,721,000	$ 628,054,000	$ 589,246,000	2,147,532,000	2,566,318,000	2,242,195,000
Segment profit (loss)	80,115,000	90,623,000	93,072,000	97,902,000	108,783,000	122,928,000	121,679,000	101,000,000	361,712,000	454,390,000	408,678,000
Total assets	4,156,266,000				4,141,909,000				4,156,266,000	4,141,909,000	3,682,517,000
Depreciation and amortization									192,240,000	169,312,000	164,437,000
Capital expenditures									345,475,000	355,144,000	253,227,000
Other segment disclosures [Abstract]
Interest expense	(4,280,000)	(4,449,000)	(4,759,000)	(5,250,000)	(5,149,000)	(5,225,000)	(5,469,000)	(5,618,000)	(18,738,000)	(21,461,000)	(27,872,000)
Gain on disposition of assets	(426,000)	400,000	(91,000)	(1,555,000)	(156,000)	(47,000)	(527,000)	(51,000)	(1,672,000)	(781,000)	(888,000)
Other income (expense)	9,000	$ 22,000	$ (303,000)	$ 60,000	125,000	$ 27,000	$ 123,000	$ (236,000)	(663,000)	(345,000)	20,000
Details of "Other" total assets [Abstract]
Investment in affiliates	2,090,000				2,539,000				2,090,000	2,539,000
Total assets	4,156,266,000				4,141,909,000				4,156,266,000	4,141,909,000	3,682,517,000
Reporting Segments [Member]
Revenues [Abstract]
Marine transportation									1,663,090,000	1,770,684,000	1,713,167,000
Diesel engine services									484,442,000	795,634,000	529,028,000
Total revenues									2,147,532,000	2,566,318,000	2,242,195,000
Segment profit (loss)									361,712,000	454,390,000	408,678,000
Depreciation and amortization									192,240,000	169,312,000	164,437,000
Capital expenditures									345,475,000	355,144,000	253,227,000
Marine Transportation [Member] \| Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									374,842,000	429,864,000	408,255,000
Total assets	3,451,553,000				3,317,696,000				3,451,553,000	3,317,696,000	3,046,692,000
Depreciation and amortization									175,798,000	154,019,000	149,574,000
Capital expenditures									311,862,000	340,315,000	237,964,000
Details of "Other" total assets [Abstract]
Total assets	3,451,553,000				3,317,696,000				3,451,553,000	3,317,696,000	3,046,692,000
Marine Transportation [Member] \| Intersegment Eliminations [Member]
Revenues [Abstract]
Total revenues									26,203,000	25,769,000	27,669,000
Segment profit (loss)									2,620,000	2,577,000	2,767,000
Diesel Engine Services [Member] \| Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									18,921,000	60,063,000	42,767,000
Total assets	637,549,000				736,129,000				637,549,000	736,129,000	576,472,000
Depreciation and amortization									12,498,000	11,463,000	11,096,000
Capital expenditures									28,907,000	7,486,000	4,658,000
Details of "Other" total assets [Abstract]
Total assets	637,549,000				736,129,000				637,549,000	736,129,000	576,472,000
Other [Member]
Revenues [Abstract]
Total assets	67,164,000				88,084,000				67,164,000	88,084,000	59,353,000
Other segment disclosures [Abstract]
General corporate expenses									(14,773,000)	(14,896,000)	(15,728,000)
Interest expense									(18,738,000)	(21,461,000)	(27,872,000)
Gain on disposition of assets									1,672,000	781,000	888,000
Other income (expense)									(212,000)	39,000	368,000
Profit (loss) from other segment									(32,051,000)	(35,537,000)	(42,344,000)
Details of "Other" total assets [Abstract]
General corporate assets	65,074,000				85,545,000				65,074,000	85,545,000	57,197,000
Investment in affiliates	2,090,000				2,539,000				2,090,000	2,539,000	2,156,000
Total assets	67,164,000				88,084,000				67,164,000	88,084,000	59,353,000
Other [Member] \| Reporting Segments [Member]
Revenues [Abstract]
Segment profit (loss)									(32,051,000)	(35,537,000)	(42,344,000)
Total assets	67,164,000				88,084,000				67,164,000	88,084,000	59,353,000
Depreciation and amortization									3,944,000	3,830,000	3,767,000
Capital expenditures									4,706,000	7,343,000	10,605,000
Details of "Other" total assets [Abstract]
Total assets	$ 67,164,000				$ 88,084,000				$ 67,164,000	$ 88,084,000	$ 59,353,000

Related Party Transactions (Details) - USD ($)	12 Months Ended
Related Party Transactions (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Richard J. Alario [Member]
Related Party Transaction [Line Items]
Oilfield service equipment	$ 572,000	$ 1,232,000	$ 1,973,000
Hollywood Camp [Member]
Related Party Transaction [Line Items]
Ownership percentage	50.00%
Facility expenses	$ 1,236,000	1,634,000	1,112,000
Share of facility expenses	2,830,000	2,303,000	2,044,000
Amy D. Husted [Member]
Related Party Transaction [Line Items]
Legal services	$ 596,000	1,184,000	851,000
Bolivar [Member]
Related Party Transaction [Line Items]
Ownership percentage	50.00%
Share of facility expenses	$ 895,000	$ 561,000	$ 703,000