Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Current Assets:
Cash and cash equivalents	$ 159	$ 321
Accounts receivable, less allowances of $3,737 and $3,881 in 2013 and 2012	117,937	106,814
Prepaid expenses and other	13,156	11,540
Deferred income taxes	20,421	18,883
Income tax receivable	13,497	2,264
Other current assets	5,083	4,341
Total current assets	170,253	144,163
Property and Equipment, at cost	797,527	718,527
Less-accumulated depreciation	365,301	356,823
Net property and equipment	432,226	361,704
Goodwill	5,231	5,231
Identifiable Intangibles, net	3,558	4,173
Other Noncurrent Assets	5,533	4,417
Total assets	616,801	519,688
Current Liabilities:
Accounts payable	50,799	43,706
Wages, vacations and employees' benefits	35,248	30,842
Claims and insurance accruals	27,637	29,350
Other current liabilities	20,030	15,259
Current portion of long-term debt	7,143	22,143
Total current liabilities	140,857	141,300
Other Liabilities:
Long-term debt, less current portion	69,740	38,562
Deferred income taxes	69,916	55,611
Claims, insurance and other	31,496	29,696
Total other liabilities	171,152	123,869
Commitments and Contingencies
Stockholders' Equity:
Preferred stock, $0.001 par value, 50,000 shares authorized, none issued and outstanding
Common stock, $0.001 par value, 50,000,000 shares authorized, 24,478,544 and 24,088,416 shares issued and outstanding at December 31, 2013 and 2012, respectively	24	24
Additional paid-in-capital	213,648	206,969
Deferred compensation trust, 201,936 and 207,755 shares of common stock at cost at December 31, 2013 and 2012, respectively	(2,246)	(2,213)
Retained earnings	93,366	49,739
Total stockholders' equity	304,792	254,519
Total liabilities and stockholders' equity	$ 616,801	$ 519,688