Consolidated Statements of Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Shares	Additional Paid-In Capital	Treasury Shares	Accumulated Other Comprehensive Loss	Retained Earnings	Total
Beginning Balance (in shares) at Dec. 31, 2016	21,184		1,367
Beginning Balance at Dec. 31, 2016	$ 212	$ 2,360,398	$ 0	$ (19,193)	$ 324,783	$ 2,666,200
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation plan (in shares)	155		(155)
Shares issued under share-based compensation plan	$ 1	(200)				(199)
Modification of unvested awards from equity to liability		(553)				(553)
Share-based compensation		6,819				6,819
Other comprehensive income				4,700		4,700
Net loss					(525,166)	(525,166)
Ending Balance (in shares) at Dec. 31, 2017	21,339		1,212
Ending Balance at Dec. 31, 2017	$ 213	2,366,464	$ 0	(14,493)	(200,383)	2,151,801
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation plan (in shares)	29		(29)
Shares issued under share-based compensation plan	$ 1	(5)				(4)
Share-based compensation		2,543				2,543
Other comprehensive income				643		643
Net loss					(2,154,877)	(2,154,877)
Ending Balance (in shares) at Nov. 19, 2018	21,368		1,183
Ending Balance at Nov. 19, 2018	$ 214	2,369,002		(13,850)	(2,355,260)	106
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reverse stock split	$ (214)	214
Reverse stock split (in shares)	(21,366)		(1,183)
Elimination of predecessor equity balances		(2,369,110)		13,850	2,355,260
Equity conversion (in shares)	24,416
Equity conversion	$ 244	1,152,199				1,152,443
Equity offerings (in shares)	50,582
Equity offerings	$ 506	492,914				493,420
Issuance of shares reserved for share-based compensation plan (in shares)			7,500
Ending Balance (in shares) at Nov. 20, 2018	75,000		7,500
Ending Balance at Nov. 20, 2018	$ 750	1,645,219				1,645,969
Beginning Balance (in shares) at Nov. 19, 2018	21,368		1,183
Beginning Balance at Nov. 19, 2018	$ 214	2,369,002		$ (13,850)	(2,355,260)	106
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation plan (in shares)	31		(31)
Shares issued under share-based compensation plan		(126)				(126)
Share-based compensation		599				599
Net loss					(27,484)	$ (27,484)
Ending Balance (in shares) at Dec. 31, 2018	75,031		7,469			75,031
Ending Balance at Dec. 31, 2018	$ 750	1,645,692			(27,484)	$ 1,618,958
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Shares issued under share-based compensation plan (in shares)	20		(20)
Shares issued under share-based compensation plan	$ 1	(82)				(81)
Shares repurchased			$ (652)			(652)
Shares repurchased (in shares)	(44)		44
Share-based compensation		7,071				7,071
Net loss					(556,465)	$ (556,465)
Ending Balance (in shares) at Dec. 31, 2019	75,007		7,493			75,007
Ending Balance at Dec. 31, 2019	$ 751	$ 1,652,681	$ (652)		$ (583,949)	$ 1,068,831