CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
CONDENSED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) [Abstract]
Net earnings	$ 63,792		$ 48,435		$ 121,344		$ 100,314
Other comprehensive income (loss), net of taxes:
Pension and postretirement benefits	494		(1,268)		1,671		(279)
Foreign currency translation adjustments	44	[1]	152	[1]	249	[1]	447	[1]
Change in fair value of derivative instruments	(4)		1,420		970		2,500
Total comprehensive income (loss), net of taxes	534	[2]	304	[2]	2,890	[2]	2,668	[2]
Total comprehensive income, net of taxes	64,326		48,739		124,234		102,982
Net earnings attributable to noncontrolling interests	(699)		(884)		(1,673)		(1,819)
Comprehensive income attributable to Kirby	$ 63,627		$ 47,855		$ 122,561		$ 101,163

[1] Actuarial gains (losses) are amortized into costs of sales and operating expenses or selling, general and administrative expenses as appropriate.  (See Note 12 – Retirement Plans)

[2] Reclassifications to net earnings of derivatives qualifying as effective hedges are recognized in interest expense or costs of sales and operating expenses as appropriate.  (See Note 6 – Derivative Instruments)