Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (157,196)	$ (107,930)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	225,044	303,584
Deferred income taxes		(25,475)
Reduction in value of assets	40,952
Right-of-use assets amortization	16,341
Stock based compensation expense	14,155	23,303
Other reconciling items, net	(9,340)	(8,255)
Changes in operating assets and liabilities:
Accounts receivable	68,239	(95,806)
Prepaid expenses	(20,012)	1,742
Inventory and other current assets	(19,966)	(16,879)
Accounts payable	(8,221)	18,367
Accrued expenses	(25,054)	(9,543)
Other, net	(8,438)	248
Net cash provided by operating activities	116,504	83,356
Cash flows from investing activities:
Payments for capital expenditures	(105,393)	(186,283)
Proceeds from sales of assets	90,696	29,595
Net cash used in investing activities	(14,697)	(156,688)
Cash flows from financing activities:
Tax withholding for vested restricted stock units	(1,677)	(5,189)
Other	621	1,239
Net cash used in financing activities	(1,056)	(3,950)
Effect of exchange rate changes on cash	(1,857)	(1,834)
Net change in cash, cash equivalents, and restricted cash	98,894	(79,116)
Cash, cash equivalents, and restricted cash at beginning of period	163,748	192,483
Cash, cash equivalents, and restricted cash at end of period	$ 262,642	$ 113,367