Consolidated Statements of Cash Flows - USD ($) $ in Thousands	1 Months Ended	11 Months Ended	12 Months Ended
	Dec. 31, 2018	Nov. 19, 2018	Dec. 31, 2019	Dec. 31, 2017
Cash flow from operating activities:
Net loss	$ (27,484)	$ (2,154,877)	$ (556,465)	$ (525,166)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization expense	27,277	248,302	193,128	278,949
Amortization of deferred revenue		(20,212)	(1,931)	(46,829)
Amortization of deferred costs	128	13,882	1,692	11,689
Amortization of deferred financing costs		1,639		24,889
Amortization of debt (premium) discount, net	(38)		(476)	940
Interest paid-in-kind	3,732	4,933	34,875
Write-off of deferred financing costs				30,846
Deferred income taxes	(6,507)	4,103	8,783	7,409
Share-based compensation expense	599	2,543	7,071	6,819
Other-than-temporary impairment of available-for-sale securities				6,829
Loss from unconsolidated subsidiaries	806		220,152
Reorganization items		1,746,764		5,315
Changes in operating assets and liabilities:
Accounts receivable	(11,670)	12,028	39,297	53,713
Materials and supplies	(122)	3,532	(3,504)	6,187
Deferred costs	(1,030)	(5,220)	(25,553)	(12,200)
Prepaid expenses and other assets	(10,953)	(27,742)	(7,393)	(8,257)
Accounts payable and accrued expenses	(16,490)	(10,096)	13,643	38,214
Deferred revenue		(481)	9,498	5,780
Net cash used in operating activities	(41,752)	(180,902)	(67,183)	(114,873)
Cash flow from investing activities:
Capital expenditures	(2,697)	(18,624)	(35,110)	(36,645)
Deconsolidation of Zonda Debtors		(4,910)
Purchase of available-for-sale securities				(6,000)
Net cash used in investing activities	(2,697)	(23,534)	(35,110)	(42,645)
Cash flow from financing activities:
Payments for shares issued under share-based compensation plan	(126)	(4)	(81)	(199)
Proceeds from debtor-in-possession financing		50,000
Payments for debtor-in-possession financing		(50,000)
Proceeds from long-term debt		1,000,000
Payments on long-term debt		(1,136,478)		(146,473)
Proceeds from equity offerings		500,000
Payments for financing costs	(13,525)	(29,355)	(1,340)	(4,530)
Purchases of treasury shares			(652)
Net cash provided by (used in) financing activities	(13,651)	334,163	(2,073)	(151,202)
Net increase (decrease) in cash and cash equivalents	(58,100)	129,727	(104,366)	(308,720)
Cash, cash equivalents and restricted cash, beginning of period	447,175	317,448	389,075	626,168
Cash, cash equivalents and restricted cash, end of period	$ 389,075	$ 447,175	$ 284,709	$ 317,448