v3.19.1
Document and Entity Information - shares
3 Months Ended
Mar. 31, 2019
May 08, 2019
Document and Entity Information [Abstract]    
Entity Registrant Name KIRBY CORP  
Entity Central Index Key 0000056047  
Current Fiscal Year End Date --12-31  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Ex Transition Period false  
Entity Common Stock, Shares Outstanding   59,901,000
Document Type 10-Q  
Amendment Flag false  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1