Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended				9 Months Ended		12 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (157,304)	$ (79,464)	$ (38,441)	$ (47,705)	$ (301,874)	$ (157,196)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion					113,313	225,044
Deferred income taxes					352
Reduction in value of assets					19,451	40,952
Reduction in value of assets held for sale					109,591
Right-of-use assets amortization					14,738	16,341
Stock-based compensation expense					6,074	14,155
Other reconciling items, net					(3,537)	(9,340)
Changes in operating assets and liabilities:
Accounts receivable					126,439	68,239
Prepaid expenses					352	(20,012)
Inventory and other current assets					15,380	(19,966)
Accounts payable					(35,828)	(8,221)
Accrued expenses					(26,409)	(25,054)
Income taxes					(3,114)	3,314
Other, net					(16,331)	(11,752)
Net cash provided by operating activities					18,597	116,504
Cash flows from investing activities:
Payments for capital expenditures					(37,408)	(105,393)
Proceeds from sales of assets					44,097	90,696
Net cash provided by (used in) investing activities					6,689	(14,697)
Cash flows from financing activities:
Delayed draw term loan commitment fee					(11,700)
Principal payments on long-term debt					(1,300,000)
Tax withholdings for vested restricted stock units					(208)	(1,677)
Other					(432)	621
Net cash used in financing activities					(12,340)	(1,056)
Effect of exchange rate changes on cash					(378)	(1,857)
Net change in cash, cash equivalents, and restricted cash					12,568	98,894
Cash, cash equivalents, and restricted cash at beginning of period		$ 275,388		$ 163,748	275,388	163,748	$ 163,748
Cash, cash equivalents, and restricted cash at end of period	$ 287,956		$ 262,642		$ 287,956	$ 262,642	$ 275,388