Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	4 Months Ended	6 Months Ended		12 Months Ended
	Apr. 23, 2021	Jun. 30, 2021	Jun. 30, 2020	Apr. 23, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Operating activities:
Net loss		$ (47,293)		$ (1,961,989)		$ (1,006,760)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	$ 18,132	18,735	$ 74,835	92,758		167,878
Loss on impairment of assets				197,027		774,028
Reorganization items, net				1,587,392		33,318
Gain on disposition of assets	(85)	(176)	(220)	(5,486)		(3,653)
Deferred tax provision		9,952		(35,894)		(14,986)
Stock-based compensation expense		1,134				5,636
Contract liabilities, net		23,572		10,617		19,809
Contract assets, net		(509)		(742)		1,337
Deferred contract costs, net		(14,987)		(12,034)		(9,492)
Long-term employee remuneration programs		120		475		(6,204)
Noncurrent collateral deposits						(18,262)
Other assets, noncurrent		(1,426)		2,685		(6,186)
Other liabilities, noncurrent		458		(371)		(1,417)
Other		534		2,683		4,493
Changes in operating assets and liabilities:
Accounts receivable		(53,759)		2,108		54,023
Prepaid expenses and other current assets		(26)		(2,791)		950
Accounts payable and accrued liabilities		(9,972)		29,302		42,139
Taxes payable		7,604		(5,804)		(3,918)
Net cash (used in) provided by operating activities		(66,039)		(100,064)		32,733
Investing activities:
Capital expenditures		(23,973)		(49,119)		(118,379)
Proceeds from disposition of assets, net of disposal costs		193		7,484		4,767
Net cash used in investing activities		(23,780)		(41,635)		(113,612)
Financing activities:
(Repayments of) borrowings under credit facility				(442,034)		436,000
Proceeds from exit facilities		30,000		200,000
Issuance of exit notes				75,000
Debt issuance costs and arrangement fees				(6,218)
Principal payments of finance lease liabilities		(2,240)
Net cash provided by (used in) financing activities		27,760		(173,252)		436,000
Net change in cash, cash equivalents and restricted cash		(62,059)		(314,951)		355,121
Cash, cash equivalents and restricted cash, beginning of period		115,429		430,380	$ 430,380	156,281	$ 156,281
Cash, cash equivalents and restricted cash, end of period	$ 115,429	$ 53,370	$ 511,402	$ 115,429	$ 53,370	$ 511,402	$ 430,380