Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 20,821	$ 5,306
Marketable securities		138
Receivables:
Trade, less allowances of $470 and $170, respectively	59,385	51,094
Other	3,430	12,968
Prepaid expenses and other	15,426	13,406
Deferred income taxes	2,738	4,794
Total current assets	101,800	87,706
Property and equipment:
Revenue equipment	468,966	469,437
Buildings and land	30,602	25,678
Office equipment and other	24,406	20,507
Less accumulated depreciation	(155,774)	(143,563)
Net property and equipment	368,200	372,059
Other assets	579	543
	470,579	460,308
Current liabilities:
Checks issued in excess of cash balances		1,066
Accounts payable	17,912	17,800
Insurance and claims accruals	13,042	17,653
Accrued liabilities	15,431	12,724
Current maturities of long-term debt		19,346
Total current liabilities	46,385	68,589
Deferred income taxes	103,835	95,815
Total liabilities	150,220	164,404
Commitments and contingencies (Note 12)
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; 21,984,597 shares at December 31, 2011, and 21,950,252 shares at December 31, 2010, issued and outstanding	220	220
Additional paid-in capital	80,078	78,428
Retained earnings	237,872	215,345
Total Marten Transport, Ltd. stockholders’ equity	318,170	293,993
Noncontrolling interest	2,189	1,911
Total stockholders’ equity	320,359	295,904
	$ 470,579	$ 460,308