Consolidated Condensed Statements of Operations (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OPERATING REVENUE	$ 164,474	$ 151,474
OPERATING EXPENSES (INCOME):
Salaries, wages and benefits	42,125	38,271
Purchased transportation	34,184	29,859
Fuel and fuel taxes	40,323	39,124
Supplies and maintenance	9,533	9,536
Depreciation	15,688	14,535
Operating taxes and licenses	1,770	1,582
Insurance and claims	5,811	5,822
Communications and utilities	1,283	1,211
Gain on disposition of revenue equipment	(2,415)	(1,525)
Other	3,634	3,540
Total operating expenses	151,936	141,955
OPERATING INCOME	12,538	9,519
NET INTEREST INCOME	(15)	(21)
INCOME BEFORE INCOME TAXES	12,553	9,540
Less: Income before income taxes attributable to noncontrolling interest	84	161
INCOME BEFORE INCOME TAXES ATTRIBUTABLE TO MARTEN TRANSPORT, LTD.	12,469	9,379
PROVISION FOR INCOME TAXES	5,267	3,933
NET INCOME	$ 7,202	$ 5,446
BASIC EARNINGS PER COMMON SHARE (in Dollars per share)	$ 0.33	$ 0.25
DILUTED EARNINGS PER COMMON SHARE (in Dollars per share)	$ 0.32	$ 0.25
DIVIDENDS PAID PER COMMON SHARE (in Dollars per share)	$ 0.025	$ 0.02