CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Net earnings (loss)	$ 122,761	$ (246,771)	$ (271,592)
Other comprehensive income (loss), net of taxes:
Pension and postretirement benefits	43,868	36,547	(23,320)
Foreign currency translation adjustments	(1,049)	(1,061)	(333)
Total other comprehensive income (loss), net of taxes	42,819	35,486	(23,653)
Total comprehensive income (loss), net of taxes	165,580	(211,285)	(295,245)
Net earnings attributable to noncontrolling interests	(470)	(183)	(954)
Comprehensive income (loss) attributable to Kirby	$ 165,110	$ (211,468)	$ (296,199)