Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (144,597)	$ (96,674)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities
Depreciation and amortization	126,417	112,209
Accretion on asset retirement obligation	212	160
Change in allowance for doubtful accounts	315	1,523
Amortization of deferred financing costs	1,072	194
Amortization of debt discounts (premiums)	4,009	7,264
Debt extinguishment costs	26,429	0
Non-cash compensation	27,254	22,954
Loss (gain) on disposal of assets	(2,598)	274
Deferred income taxes	(78)	78
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	3,384	(41,303)
Inventories	(46)	(712)
Prepaid expenses and other current assets	5,248	(7,065)
Other assets	532	(1,244)
Accounts payable	18,267	25,548
Income tax receivable	305	(607)
Other liabilities	4,361	2,704
Accrued expenses	3,853	644
Net cash provided by operating activities	74,339	25,947
Cash flows from investing activities:
Purchase of property and equipment	(68,709)	(63,361)
Proceeds from sale of assets	17,785	9,814
Net cash used in investing activities	(50,924)	(53,547)
Cash flows from financing activities:
Proceeds from debt	332,500	64,000
Payments of debt	(318,929)	(46,589)
Debt extinguishment costs	(17,607)	0
Change in treasury stock including restricted stock issuances	(1,882)	(2,035)
Deferred loan costs and other financing activities	(13,420)	(2,857)
Net cash (used in) provided by financing activities	(19,338)	12,519
Net (decrease) increase in cash and equivalents	4,077	(15,081)
Cash and cash equivalents - beginning of year	86,223	101,304
Cash and cash equivalents - end of year	90,300	86,223
Noncash investing and financing activity:
Capital leases and notes issued for equipment	20,197	67,510
Change in accrued property and equipment	$ (462)	$ 7,011