Revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Revenues (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Abstract]
Revenues by major source	$ 871,161	$ 831,149	$ 2,512,275	$ 2,463,561
Revenue recognized			112,800	101,800
Marine Transportation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	484,941	486,054	1,453,652	1,446,274
Marine Transportation [Member] \| Inland Transportation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	379,329	392,617	1,168,969	1,170,459
Marine Transportation [Member] \| Coastal Transportation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	105,612	93,437	284,683	275,815
Distribution and Services [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	386,220	345,095	1,058,623	1,017,287
Distribution and Services [Member] \| Commercial and Industrial [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	168,079	162,285	501,913	470,567
Distribution and Services [Member] \| Power generation [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	173,916	111,573	419,157	355,025
Distribution and Services [Member] \| Oil and gas [Member]
Disaggregation of Revenue [Abstract]
Revenues by major source	$ 44,225	$ 71,237	$ 137,553	$ 191,695

KIRBY CORP 10-Q