Document and Entity Information (USD $)
3 Months Ended
Mar. 31, 2012
May 02, 2012
Jun. 30, 2011
Document And Entity Information [Abstract]      
Entity Registrant Name KIRBY CORP    
Entity Central Index Key 0000056047    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 0.00
Entity Common Stock, Shares Outstanding   55,874,000.00  
Document Fiscal Year Focus 2012    
Document Fiscal Period Focus Q1    
Document Type 10-Q    
Amendment Flag false    
Document Period End Date Mar. 31, 2012