CONDENSED STATEMENTS OF EARNINGS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues:
Revenues	$ 824,390	$ 777,248	$ 1,632,412	$ 1,527,692
Costs and expenses:
Costs of sales and operating expenses	554,232	546,069	1,104,913	1,088,149
Selling, general and administrative	80,383	82,896	170,589	171,745
Taxes, other than on income	10,310	9,758	18,354	18,944
Depreciation and amortization	59,482	51,697	117,124	102,806
Gain on disposition of assets	(515)	(472)	(589)	(2,702)
Total costs and expenses	703,892	689,948	1,410,391	1,378,942
Operating income	120,498	87,300	222,021	148,750
Other income	3,088	1,264	6,357	7,707
Interest expense	(12,819)	(12,286)	(25,970)	(25,507)
Earnings before taxes on income	110,767	76,278	202,408	130,950
Provision for taxes on income	(26,785)	(18,960)	(48,511)	(33,011)
Net earnings	83,982	57,318	153,897	97,939
Net (earnings) loss attributable to noncontrolling interests	(128)	49	25	126
Net earnings attributable to Kirby	$ 83,854	$ 57,367	$ 153,922	$ 98,065
Net earnings per share attributable to Kirby common stockholders:
Basic	$ 1.44	$ 0.96	$ 2.64	$ 1.64
Diluted	$ 1.43	$ 0.95	$ 2.62	$ 1.63
Marine Transportation [Member]
Revenues:
Revenues	$ 484,808	$ 426,962	$ 960,220	$ 839,457
Distribution and Services [Member]
Revenues:
Revenues	$ 339,582	$ 350,286	$ 672,192	$ 688,235