Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income (loss)	$ 6,065	$ (14,267)	$ 3,289
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Provision for losses on accounts receivable	904	713	422
Deferred gain on sales of equipment to affiliate	198	562
Depreciation and amortization	48,135	53,001	56,100
Goodwill impairment		11,539
Amortization of deferred financing fees	492	414	715
(Reversal into earnings) deferred gain on fuel hedge		(773)	773
Casualty premium credit	(4,000)
Equity in income of affiliate	(1,875)	(675)
Deferred income tax expense (benefit)	6,735	(2,158)	17,422
(Gain) loss on disposition of property and equipment	(4,913)	(6,727)	(4,293)
Income tax benefit arising from restricted share vesting and exercise of stock options		(432)	(421)
Stock-based compensation expense	1,284	1,226	1,118
Receivables and advances	(10,415)	(4,348)	1,018
Prepaid expenses and other assets	4,630	1,513	(2,097)
Inventory and supplies	61	(130)	(477)
Insurance and claims accrual	3,979	1,056	1,690
Accounts payable and accrued expenses	3,821	(8,453)	(4,420)
Net cash flows provided by operating activities	55,101	32,061	70,839
Cash flows from investing activities:
Acquisition of property and equipment	(41,787)	(114,800)	(137,347)
Investment in affiliated company	(2,900)	(1,500)
Return of investment in affiliated company	316	241
Proceeds from disposition of property and equipment	57,525	65,318	55,075
Net cash flows provided by (used in) investing activities	13,154	(50,741)	(82,272)
Cash flows from financing activities:
Payment of minimum tax withholdings on stock compensation	(9)	(561)	(284)
Proceeds from the exercise of stock options			1,308
(Repayments) proceeds from/of borrowings under revolving credit facility, net	(15,885)	15,869	(12,665)
Repayments of capital lease obligation	(1,992)	(1,651)	(1,158)
Change in checks outstanding in excess of bank balances	2,298	1,168	(43)
Proceeds from issuance of notes payable	26,395	85,152	97,766
Repayments of notes payable	(76,085)	(86,938)	(76,208)
Debt refinancing costs	(26)	(257)	(564)
Income tax benefit arising from restricted share vesting and exercise of stock options		432	421
Net cash flows (used in) provided by financing activities	(65,304)	13,214	8,573
Net change in cash and cash equivalents	2,951	(5,466)	(2,860)
Cash and cash equivalents at beginning of year	3,895	9,361	12,221
Cash and cash equivalents at end of year	6,846	3,895	9,361
Supplemental disclosure of cash flow information:
Interest, net of capitalized interest	12,967	16,236	16,710
Income taxes	342	(295)	(7,928)
Equipment purchased under capital leases		4,920	2,405
Accrued investment in TEL	500	1,000
Noncash change in insurance claims accruals recorded in excess of retention	$ 1,236