CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $)	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Income [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interests [Member]	Total
Balance at beginning of year at Dec. 31, 2009	$ 5,734,000	$ 229,724,000	$ (30,468,000)	$ 930,366,000	$ (82,893,000)	$ 3,632,000
Issuance of shares in acquisition	0	0
Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		3,140,000
Tax benefit realized from equity compensation plans		373,000					373,000
Issuance of restricted stock, net of forfeitures		(7,090,000)
Amortization of unearned compensation		10,867,000
Net earnings attributable to Kirby for the year				116,249,000			116,249,000
Purchase of treasury stock (618,000 shares in 2010)					(23,793,000)
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (341,000 in 2012, 248,000 in 2011 and 338,000 in 2010)					7,064,000
Net earnings attributable to noncontrolling interests						1,133,000	1,133,000
Return of investment to noncontrolling interests						(1,794,000)	(1,794,000)
Proceeds from noncontrolling interest investments						69,000	69,000
Acquisition of noncontrolling interests						0
Other comprehensive loss, net of taxes			(3,174,000)				(3,174,000)
Balance at end of year at Dec. 31, 2010	5,734,000	237,014,000	(33,642,000)	1,046,615,000	(99,622,000)	3,040,000
Issuance of shares in acquisition	194,000	112,825,000
Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		4,359,000
Tax benefit realized from equity compensation plans		1,348,000					1,348,000
Issuance of restricted stock, net of forfeitures		(7,480,000)
Amortization of unearned compensation		9,228,000
Net earnings attributable to Kirby for the year				183,026,000			183,026,000
Purchase of treasury stock (618,000 shares in 2010)					0
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (341,000 in 2012, 248,000 in 2011 and 338,000 in 2010)					5,460,000
Net earnings attributable to noncontrolling interests						2,466,000	2,466,000
Return of investment to noncontrolling interests						(2,115,000)	(2,115,000)
Proceeds from noncontrolling interest investments						268,000	268,000
Acquisition of noncontrolling interests						7,974,000
Other comprehensive loss, net of taxes			(22,534,000)				(22,534,000)
Balance at end of year at Dec. 31, 2011	5,928,000	357,294,000	(56,176,000)	1,229,641,000	(94,162,000)	11,633,000	1,454,158,000
Issuance of shares in acquisition	50,000	29,030,000
Excess of proceeds received upon exercise of stock options and issuance of restricted stock over cost of treasury stock issued		6,716,000
Tax benefit realized from equity compensation plans		3,212,000					3,212,000
Issuance of restricted stock, net of forfeitures		(8,263,000)
Amortization of unearned compensation		9,796,000
Net earnings attributable to Kirby for the year				209,438,000			209,438,000
Purchase of treasury stock (618,000 shares in 2010)					0
Cost of treasury stock issued upon exercise of stock options and issuance of restricted stock (341,000 in 2012, 248,000 in 2011 and 338,000 in 2010)					7,415,000
Net earnings attributable to noncontrolling interests						3,181,000	3,181,000
Return of investment to noncontrolling interests						(2,728,000)	(2,728,000)
Proceeds from noncontrolling interest investments						0	0
Acquisition of noncontrolling interests						0
Other comprehensive loss, net of taxes			(4,951,000)				(4,951,000)
Balance at end of year at Dec. 31, 2012	$ 5,978,000	$ 397,785,000	$ (61,127,000)	$ 1,439,079,000	$ (86,747,000)	$ 12,086,000	$ 1,707,054,000