Consolidated Statements of Operations (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating revenue	$ 638,456	$ 603,679	$ 516,920
Operating expenses (income):
Salaries, wages and benefits	163,242	147,646	131,519
Purchased transportation	124,269	120,332	110,408
Fuel and fuel taxes	163,596	155,595	114,927
Supplies and maintenance	39,919	40,311	35,218
Depreciation	60,904	57,531	51,916
Operating taxes and licenses	6,741	6,373	6,222
Insurance and claims	20,718	18,170	16,573
Communications and utilities	4,939	4,605	3,964
Gain on disposition of revenue equipment	(5,302)	(3,800)	(1,110)
Other	13,577	13,886	11,994
	592,603	560,649	481,631
Operating income	45,853	43,030	35,289
Net interest income	(48)	(24)	(26)
Income before income taxes	45,901	43,054	35,315
Less: Income before income taxes attributable to noncontrolling interest	497	807	631
Income before income taxes attributable to Marten Transport, Ltd.	45,404	42,247	34,684
Provision for income taxes	18,137	17,962	14,942
Net income	$ 27,267	$ 24,285	$ 19,742
Basic earnings per common share (in Dollars per share)	$ 1.24	$ 1.10	$ 0.90
Diluted earnings per common share (in Dollars per share)	$ 1.23	$ 1.10	$ 0.90
Dividends paid per common share (in Dollars per share)	$ 0.845	$ 0.08	$ 0.04