CONDENSED STATEMENTS OF EARNINGS (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Revenues:
Total revenues	$ 744,621	$ 741,688
Costs and expenses:
Costs of sales and operating expenses	536,655	553,317
Selling, general and administrative	72,796	76,796
Taxes, other than on income	9,998	8,535
Depreciation and amortization	55,223	54,218
Gain on disposition of assets	(2,157)	(1,898)
Total costs and expenses	672,515	690,968
Operating income	72,106	50,720
Other income (expense)	(568)	1,591
Interest expense	(13,201)	(9,780)
Earnings before taxes on income	58,337	42,531
Provision for taxes on income	(13,880)	(9,865)
Net earnings	44,457	32,666
Less: Net earnings attributable to noncontrolling interests	(161)	(195)
Net earnings attributable to Kirby	$ 44,296	$ 32,471
Net earnings per share attributable to Kirby common stockholders:
Basic (in dollars per share)	$ 0.74	$ 0.54
Diluted (in dollars per share)	$ 0.74	$ 0.54
Marine Transportation [Member]
Revenues:
Total revenues	$ 368,121	$ 340,403
Distribution and Services [Member]
Revenues:
Total revenues	$ 376,500	$ 401,285