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)	$ 20,854	$ 47,163	$ (43,563)
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	187,083	154,341	135,001
Gain on bargain purchase	(910)		(1,772)
Accretion on asset retirement obligation	110	124	162
Change in allowance for doubtful accounts	1,550	(1,848)	(1,679)
Amortization of deferred financing costs	2,831	2,349	1,567
Amortization of discount or premium on notes	(208)	6,385	1,937
Non-cash compensation	12,286	7,955	5,666
Loss on early extinguishment of debt (non-cash)	1,839	3,940
Payment of Premium and Consent for Senior Secured Notes	6,118	36,179
Loss on disposal of assets	3,334	447	2,856
Deferred income taxes	11,590	30,695	(5,993)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	49,246	(88,863)	(55,304)
Inventories	(5,267)	(12,057)	(2,411)
Prepaid expenses and other current assets	564	(1,344)	4,800
Other assets	927	(2,853)	(949)
Accounts payable	4,720	12,140	16,002
Excess tax expense from exercise of employee stock options / vesting of restricted stock			292
Income tax receivable	(2,239)	79,166	(17,986)
Other liabilities	1,423	(6,941)	3,074
Accrued expenses	7,830	12,477	7,683
Net cash provided by operating activities	303,681	279,455	49,383
Cash flows from investing activities:
Purchase of property and equipment	(171,440)	(221,839)	(63,579)
Purchase of mutual fund	(5,635)
Proceeds from sale of assets	12,069	20,843	2,521
Change in restricted cash			14,123
Payments for other long-term assets	(817)	(624)	(666)
Payments for businesses, net of cash acquired	(84,939)	(218,347)	(50,278)
Net cash used in investing activities	(250,762)	(419,967)	(97,879)
Cash flows from financing activities:
Proceeds from debt	300,000	498,850
Payments of debt	(266,949)	(278,696)	(28,253)
Premium on retirement of senior notes	(6,118)	(36,179)
Purchase of treasury stock	(18,497)	(1,872)	(359)
Excess tax expense from exercise of employee stock options / vesting of restricted stock			(292)
Tax withholding from exercise of stock options	(142)	(3,175)	(108)
Exercise of employee stock options	940	7,709	430
Deferred loan costs and other financing activities	(6,046)	(15,585)	(361)
Net cash provided by or (used) in financing activities	3,188	171,052	(28,943)
Net increase in cash and equivalents	56,107	30,540	(77,439)
Cash and cash equivalents - beginning of year	78,458	47,918	125,357
Cash and cash equivalents - end of year	$ 134,565	$ 78,458	$ 47,918