CONDENSED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ 39,244	$ (265,152)	$ 85,436	$ (257,920)
Other comprehensive income, net of taxes:
Pension and postretirement benefits	9,110	3,142	13,254	7,494
Foreign currency translation adjustments	(608)	(122)	(743)	(705)
Total other comprehensive income, net of taxes	8,502	3,020	12,511	6,789
Total comprehensive income (loss), net of taxes	47,746	(262,132)	97,947	(251,131)
Net (earnings) loss attributable to noncontrolling interests	(153)	422	(454)	5
Comprehensive income (loss) attributable to Kirby	$ 47,593	$ (261,710)	$ 97,493	$ (251,126)