Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
CURRENT ASSETS
Cash and cash equivalents	$ 127,506	$ 119,838
Trade receivables, net	51,747	46,555
Prepaid tires	5,834	6,603
Other current assets	10,204	2,281
Income tax receivable	0	2,351
Deferred income taxes, net	14,251	13,797
Total current assets	209,542	191,425
PROPERTY AND EQUIPMENT
Land and land improvements	17,451	17,451
Buildings	27,559	26,761
Furniture and fixtures	2,269	2,269
Shop and service equipment	7,257	7,266
Revenue equipment	395,857	378,583
Property, Plant and Equipment, Gross	450,393	432,330
Less accumulated depreciation	178,682	189,959
Property and equipment, net	271,711	242,371
LONG-TERM INVESTMENTS	19,991	20,016
GOODWILL	4,815	4,815
OTHER ASSETS	9,141	9,110
Assets	515,200	467,737
CURRENT LIABILITIES
Accounts payable and accrued liabilities	27,590	7,583
Compensation and benefits	17,316	16,409
Insurance accruals	12,631	13,924
Income taxes payable	5,638	0
Other accruals	8,458	7,439
Total current liabilities	71,633	45,355
LONG-TERM LIABILITIES
Income taxes payable	22,118	23,122
Deferred income taxes, net	54,938	51,306
Insurance accruals less current portion	57,760	57,590
Total long-term liabilities	134,816	132,018
COMMITMENTS AND CONTINGENCIES (Note 11)
STOCKHOLDERS' EQUITY
Preferred stock, par value $.01; authorized 5,000 shares; none issued	0	0
Capital stock, common, $.01 par value; authorized 395,000 shares; issued 90,689 in 2013 and 2012; outstanding, 84,770 in 2013 and 2012	907	907
Additional paid-in capital	3,322	2,968
Retained earnings	386,346	368,313
Treasury stock, at cost; 5,919 shares in 2013 and 2012	(80,540)	(80,540)
Accumulated other comprehensive loss	(1,284)	(1,284)
Stockholders' Equity Attributable to Parent	308,751	290,364
Liabilities and Stockholders' Equity	$ 515,200	$ 467,737