Document And Entity Information (USD $)
12 Months Ended
Dec. 31, 2011
Feb. 22, 2012
Jun. 30, 2011
Document And Entity Information [Abstract]      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Dec. 31, 2011    
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus FY    
Entity Registrant Name KIRBY CORP    
Entity Central Index Key 0000056047    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   55,847,000  
Entity Well-known Seasoned Issuer Yes    
Entity Public Float     $ 2,915,796,000
Entity Current Reporting Status Yes    
Entity Voluntary Filers No