Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Cash and cash equivalents	$ 22,604	$ 23,678
Accounts receivable, trade, less allowance of $10,017 and $9,939, respectively	266,727	231,647
Other receivables	20,316	10,769
Inventories and supplies	17,824	15,743
Prepaid taxes, licenses and permits	14,914	15,064
Current deferred income taxes	34,066	25,315
Income taxes receivable	23,435	3,346
Other current assets	26,458	24,099
Total current assets	426,344	349,661
Property and equipment, at cost:
Land	32,213	31,445
Buildings and improvements	130,618	132,023
Revenue equipment	1,413,178	1,364,064
Service equipment and other	210,220	200,205
Total property and equipment	1,786,229	1,727,737
Less – accumulated depreciation	772,447	750,219
Property and equipment, net	1,013,782	977,518
Other non-current assets	40,336	26,918
Total assets	1,480,462	1,354,097
Current liabilities:
Accounts payable	64,827	66,678
Insurance and claims accruals	73,814	59,811
Accrued payroll	28,121	22,785
Other current liabilities	19,768	18,457
Total current liabilities	186,530	167,731
Long-term debt, net of current portion	75,000	40,000
Other long-term liabilities	20,021	14,710
Insurance and claims accruals, net of current portion	123,445	131,900
Deferred income taxes	241,606	227,237
Commitments and contingencies
Stockholders’ equity:
Common stock, $0.01 par value, 200,000,000 shares authorized; 80,533,536 shares issued; 72,038,368 and 72,713,920 shares outstanding, respectively	805	805
Paid-in capital	101,803	98,534
Retained earnings	915,085	830,842
Accumulated other comprehensive loss	(9,375)	(4,631)
Treasury stock, at cost; 8,495,168 and 7,819,616 shares, respectively	(174,458)	(153,031)
Total stockholders’ equity	833,860	772,519
Total liabilities and stockholders’ equity	$ 1,480,462	$ 1,354,097