v3.5.0.2
Document and Entity Information - shares
6 Months Ended
Jun. 30, 2016
Aug. 05, 2016
Document and Entity Information [Abstract]    
Entity Registrant Name KIRBY CORP  
Entity Central Index Key 0000056047  
Current Fiscal Year End Date --12-31  
Entity Well-known Seasoned Issuer Yes  
Entity Voluntary Filers No  
Entity Current Reporting Status Yes  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   53,856,000
Document Fiscal Year Focus 2016  
Document Fiscal Period Focus Q2  
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Jun. 30, 2016