Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (79,464)	$ (47,705)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation, depletion, amortization and accretion	41,355	82,439
Deferred income taxes	3,882
Reduction in value of assets	16,522
Reduction in value of assets held for sale	46,358
Right-of-use assets amortization	4,373	5,741
Stock-based compensation expense	3,584	8,453
Other reconciling items, net	1,776	(9,727)
Changes in operating assets and liabilities:
Accounts receivable	(3,448)	26,590
Prepaid expenses	4,129	(7,333)
Inventory and other current assets	(2,077)	1,392
Accounts payable	(17,086)	(8,172)
Accrued expenses	(20,540)	(17,709)
Income taxes	(28,479)
Other, net	(3,125)	(6,590)
Net cash provided by (used in) operating activities	(32,240)	27,379
Cash flows from investing activities:
Payments for capital expenditures	(18,563)	(41,160)
Proceeds from sales of assets	33,045	5,066
Net cash provided by (used in) investing activities	14,482	(36,094)
Cash flows from financing activities:
Tax withholdings for vested restricted stock units	(208)	(1,667)
Net cash used in financing activities	(208)	(1,667)
Effect of exchange rate changes on cash	(2,428)	924
Net change in cash, cash equivalents, and restricted cash	(20,394)	(9,458)
Cash, cash equivalents, and restricted cash at beginning of period	275,388	163,748	$ 163,748
Cash, cash equivalents, and restricted cash at end of period	$ 254,994	$ 154,290	$ 275,388