Consolidated Condensed Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 5,249	$ 20,821
Receivables:
Trade, net	64,114	59,385
Other	5,399	3,430
Prepaid expenses and other	14,033	15,426
Deferred income taxes	2,508	2,738
Total current assets	91,303	101,800
Property and equipment:
Revenue equipment, buildings and land, office equipment and other	547,812	523,974
Accumulated depreciation	(145,245)	(155,774)
Net property and equipment	402,567	368,200
Other assets	597	579
TOTAL ASSETS	494,467	470,579
Current liabilities:
Accounts payable and accrued liabilities	41,463	33,343
Insurance and claims accruals	12,414	13,042
Total current liabilities	53,877	46,385
Deferred income taxes	106,216	103,835
Total liabilities	160,093	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 June 30, 2012, and 21,984,597 shares at December 31, 2011, issued and outstanding	221	220
Additional paid-in capital	81,834	80,078
Retained earnings	249,909	237,872
Total Marten Transport, Ltd. stockholders’ equity	331,964	318,170
Noncontrolling interest	2,410	2,189
Total stockholders’ equity	334,374	320,359
TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY	$ 494,467	$ 470,579