Consolidated Condensed Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 5,127	$ 20,821
Receivables:
Trade, net	68,841	59,385
Other	4,738	3,430
Prepaid expenses and other	13,186	15,426
Deferred income taxes	2,431	2,738
Total current assets	94,323	101,800
Property and equipment:
Revenue equipment, buildings and land, office equipment and other	556,323	523,974
Accumulated depreciation	(149,280)	(155,774)
Net property and equipment	407,043	368,200
Other assets	606	579
TOTAL ASSETS	501,972	470,579
Current liabilities:
Accounts payable and accrued liabilities	40,782	33,343
Insurance and claims accruals	13,327	13,042
Total current liabilities	54,109	46,385
Deferred income taxes	107,251	103,835
Total liabilities	161,360	150,220
Marten Transport, Ltd. 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; 22,071,249 shares at September 30, 2012, and 21,984,597 shares at December 31, 2011, issued and outstanding	221	220
Additional paid-in capital	82,090	80,078
Retained earnings	255,875	237,872
Total Marten Transport, Ltd. stockholders’ equity	338,186	318,170
Noncontrolling interest	2,426	2,189
Total stockholders’ equity	340,612	320,359
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 501,972	$ 470,579