Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Cash flows from operating activities:
Net income (loss)	$ 536	$ (21,574)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	103,490	101,848
Accretion on asset retirement obligation	64	55
Change in allowance for doubtful accounts	(336)	224
Amortization of deferred financing costs	1,605	1,512
Amortization of premium on notes	(118)	(108)
Non-cash compensation	7,121	6,129
Loss on disposal of assets	237	1,879
Deferred income taxes	701	(10,755)
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	(28,170)	(18,346)
Inventories	(6,720)	158
Prepaid expenses and other current assets	(3,917)	(2,730)
Other assets	(824)	229
Accounts payable	9,229	(4,874)
Income tax receivable	269	(791)
Other liabilities	3,761	2,395
Accrued expenses	7,083	13,118
Net cash provided by operating activities	94,011	68,369
Cash flows from investing activities:
Purchase of property and equipment	(107,384)	(77,599)
Proceeds from sale of mutual fund		5,635
Proceeds from sale of assets	25,875	7,658
Payments for other long-term assets	(673)	(569)
Payments for businesses, net of cash acquired		(16,463)
Net cash used in investing activities	(82,182)	(81,338)
Cash flows from financing activities:
Payments of debt	(22,346)	(22,632)
Purchase of treasury stock	(6,243)	(3,528)
Tax withholding from exercise of stock options	(362)	(154)
Exercise of employee stock options	4,646	456
Deferred loan costs and other financing activities	(62)	(119)
Net cash used in financing activities	(24,367)	(25,977)
Net decrease in cash and equivalents	(12,538)	(38,946)
Cash and cash equivalents - beginning of period	111,532	134,565
Cash and cash equivalents - end of period	$ 98,994	$ 95,619