Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current assets:
Cash and cash equivalents	$ 13,650	$ 3,473
Receivables:
Trade, less allowances of $450 and $334, respectively	70,869	66,239
Other	4,142	7,177
Prepaid expenses and other	15,274	15,490
Deferred income taxes	3,415	3,155
Total current assets	107,350	95,534
Property and equipment:
Less accumulated depreciation	(164,916)	(156,660)
Net property and equipment	415,009	394,476
Other assets	3,443	613
	525,802	490,623
Current liabilities:
Accounts payable	19,373	16,081
Insurance and claims accruals	14,404	13,838
Accrued liabilities	19,251	16,981
Total current liabilities	53,028	46,900
Long-term debt, less current maturities		2,726
Deferred income taxes	113,637	109,074
Total liabilities	166,665	158,700
Stockholders’ equity:
Preferred stock, $.01 par value per share; 2,000,000 shares authorized; no shares issued and outstanding
Common stock, $.01 par value per share; 48,000,000 shares authorized; 33,301,048 shares at December 31, 2013, and 33,164,428 shares at December 31, 2012, issued and outstanding	333	332
Additional paid-in capital	85,077	82,679
Retained earnings	273,727	246,349
Total Marten Transport, Ltd. stockholders’ equity	359,137	329,360
Noncontrolling interest		2,563
Total stockholders’ equity	359,137	331,923
	525,802	490,623
Revenue Equipment [Member]
Property and equipment:
Property and equipment	496,133	484,350
Land and Building [Member]
Property and equipment:
Property and equipment	52,213	39,664
Office Equipment And Other [Member]
Property and equipment:
Property and equipment	$ 31,579	$ 27,122