CONDENSED STATEMENTS OF EARNINGS (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenues:
Total revenues	$ 541,159	$ 771,042	$ 1,185,085	$ 1,515,663
Costs and expenses:
Costs of sales and operating expenses	373,539	563,495	827,107	1,100,150
Selling, general and administrative	65,612	69,150	137,692	141,946
Taxes, other than on income	13,065	10,579	24,471	20,577
Depreciation and amortization	54,502	55,093	110,288	110,316
Impairments and other charges	0	0	561,274	0
(Gain) loss on disposition of assets	189	(3,118)	(303)	(5,275)
Total costs and expenses	506,907	695,199	1,660,529	1,367,714
Operating income (loss)	34,252	75,843	(475,444)	147,949
Other income	2,290	2,381	5,013	1,813
Interest expense	(12,708)	(15,515)	(25,507)	(28,716)
Earnings (loss) before taxes on income	23,834	62,709	(495,938)	121,046
(Provision) benefit for taxes on income	1,429	(15,269)	174,238	(29,149)
Net earnings (loss)	25,263	47,440	(321,700)	91,897
Less: Net earnings attributable to noncontrolling interests	(261)	(153)	(539)	(314)
Net earnings (loss) attributable to Kirby	$ 25,002	$ 47,287	$ (322,239)	$ 91,583
Net earnings (loss) per share attributable to Kirby common stockholders:
Basic (in dollars per share)	$ 0.42	$ 0.79	$ (5.38)	$ 1.53
Diluted (in dollars per share)	$ 0.42	$ 0.79	$ (5.38)	$ 1.53
Marine Transportation [Member]
Revenues:
Total revenues	$ 380,987	$ 404,286	$ 784,244	$ 772,407
Distribution and Services [Member]
Revenues:
Total revenues	$ 160,172	$ 366,756	$ 400,841	$ 743,256