CONDENSED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenues:
Revenues	$ 777,248	$ 697,964	$ 1,527,692	$ 1,308,746
Costs and expenses:
Costs of sales and operating expenses	546,069	523,862	1,088,149	974,480
Selling, general and administrative	82,896	70,575	171,745	146,340
Taxes, other than on income	9,758	9,621	18,944	19,211
Depreciation and amortization	51,697	50,115	102,806	100,079
Gain on disposition of assets	(472)	(2,745)	(2,702)	(7,594)
Total costs and expenses	689,948	651,428	1,378,942	1,232,516
Operating income	87,300	46,536	148,750	76,230
Other income	1,264	3,740	7,707	8,048
Interest expense	(12,286)	(10,640)	(25,507)	(20,843)
Earnings before taxes on income	76,278	39,636	130,950	63,435
Provision for taxes on income	(18,960)	(11,030)	(33,011)	(17,243)
Net earnings	57,318	28,606	97,939	46,192
Net (earnings) loss attributable to noncontrolling interests	49	(149)	126	(301)
Net earnings attributable to Kirby	$ 57,367	$ 28,457	$ 98,065	$ 45,891
Net earnings per share attributable to Kirby common stockholders:
Basic	$ 0.96	$ 0.47	$ 1.64	$ 0.76
Diluted	$ 0.95	$ 0.47	$ 1.63	$ 0.76
Marine Transportation [Member]
Revenues:
Revenues	$ 426,962	$ 405,655	$ 839,457	$ 761,191
Distribution and Services [Member]
Revenues:
Revenues	$ 350,286	$ 292,309	$ 688,235	$ 547,555