Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS
Cash and cash equivalents	$ 172,312	$ 139,770
Trade receivables, net	50,119	44,198
Prepaid tires	11,931	12,820
Other current assets	3,631	1,932
Income tax receivable	0	314
Deferred income taxes, net	15,211	14,401
Total current assets	253,204	213,435
PROPERTY AND EQUIPMENT
Land and land improvements	17,451	17,451
Buildings	26,761	26,761
Furniture and fixtures	2,269	2,269
Shop and service equipment	7,324	7,324
Revenue equipment	348,223	355,905
Property, Plant and Equipment, Gross	402,028	409,710
Less accumulated depreciation	168,381	161,269
Property and equipment, net	233,647	248,441
LONG-TERM INVESTMENTS	50,544	50,569
GOODWILL	4,815	4,815
OTHER ASSETS	8,457	8,406
Assets	550,667	525,666
CURRENT LIABILITIES
Accounts payable and accrued liabilities	11,297	9,088
Compensation and benefits	16,312	15,493
Insurance accruals	13,751	13,997
Income taxes payable	10,491	0
Other accruals	8,028	7,085
Total current liabilities	59,879	45,663
LONG-TERM LIABILITIES
Income taxes payable	22,395	24,077
Deferred income taxes, net	55,417	57,661
Insurance accruals less current portion	56,451	57,494
Total long-term liabilities	134,263	139,232
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 2012 and 2011, outstanding, 86,475 in 2012 and 2011, respectively	907	907
Additional paid-in capital	1,491	589
Retained earnings	413,558	398,706
Treasury stock, at cost; 4,214 shares in 2012 and 2011	(56,350)	(56,350)
Accumulated other comprehensive loss	(3,081)	(3,081)
Stockholders' Equity Attributable to Parent	356,525	340,771
Liabilities and Stockholders' Equity	$ 550,667	$ 525,666