ACCOUNTING STANDARDS ADOPTIONS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating expense	$ 690,968	$ 445,661
Nonoperating expense	(1,591)	589
Statements of earnings [Abstract]
Revenues	741,688	491,705
Costs of sales and operating expenses	553,317	344,799
Operating income	50,720	46,044
Earnings before taxes on income	42,531	40,998
Provision for taxes on income	(9,865)	(13,353)
Net earnings attributable to Kirby	32,471	27,483
Statements of comprehensive income [Abstract]
Net earnings	32,666	27,645
Comprehensive income attributable to Kirby	25,396	28,229
Balance sheets [Abstract]
Trade receivables	485,865		$ 452,222
Inventories	372,182		315,729
Total assets	5,714,500		5,127,427
Deferred revenues	81,216		48,347
Deferred income taxes	517,421		468,451
Retained earnings	2,677,611		2,646,937
Total liabilities and equity	5,714,500		$ 5,127,427
Statements of cash flows [Abstract]
Net earnings	32,666	27,645
Provision for deferred income taxes	8,846	8,562
Decrease in cash flows resulting from changes in operating assets and liabilities, net	(87,926)	(8,140)
Distribution and Services [Member]
Statements of earnings [Abstract]
Revenues	401,285	148,053
ASU 2018-02 [Member] | Accumulated Other Comprehensive Income (Loss) [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from AOCI to retained earnings	(7,925)
ASU 2018-02 [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reclassification from AOCI to retained earnings	7,925
ASU 2017-07 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating expense		(473)
Nonoperating expense		$ 473
ASC 606 [Member] | Balances without Adoption of ASC 606 [Member]
Statements of earnings [Abstract]
Costs of sales and operating expenses	574,817
Operating income	56,520
Earnings before taxes on income	48,331
Provision for taxes on income	(11,216)
Net earnings attributable to Kirby	36,920
Statements of comprehensive income [Abstract]
Net earnings	37,115
Comprehensive income attributable to Kirby	29,845
Balance sheets [Abstract]
Trade receivables	495,875
Inventories	350,682
Total assets	5,703,010
Deferred revenues	63,926
Deferred income taxes	518,772
Retained earnings	2,682,060
Total liabilities and equity	5,703,010
Statements of cash flows [Abstract]
Net earnings	37,115
Provision for deferred income taxes	10,197
Decrease in cash flows resulting from changes in operating assets and liabilities, net	(76,436)
ASC 606 [Member] | Balances without Adoption of ASC 606 [Member] | Distribution and Services [Member]
Statements of earnings [Abstract]
Revenues	428,585
ASC 606 [Member] | Effect of Change [Member]
Statements of earnings [Abstract]
Costs of sales and operating expenses	(21,500)
Operating income	(5,800)
Earnings before taxes on income	(5,800)
Provision for taxes on income	1,351
Net earnings attributable to Kirby	(4,449)
Statements of comprehensive income [Abstract]
Net earnings	(4,449)
Comprehensive income attributable to Kirby	(4,449)
Balance sheets [Abstract]
Trade receivables	(10,010)
Inventories	21,500
Total assets	11,490
Deferred revenues	17,290
Deferred income taxes	(1,351)
Retained earnings	(4,449)
Total liabilities and equity	11,490
Statements of cash flows [Abstract]
Net earnings	(4,449)
Provision for deferred income taxes	(1,351)
Decrease in cash flows resulting from changes in operating assets and liabilities, net	(11,490)
ASC 606 [Member] | Effect of Change [Member] | Distribution and Services [Member]
Statements of earnings [Abstract]
Revenues	(27,300)
ASC 606 [Member] | Retained Earnings [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect on retained earnings	$ (9,722)