Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended				6 Months Ended
	Jan. 15, 2021	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Class of Warrant or Right, Date from which Warrants or Rights Exercisable	Jan. 15, 2021
Anti-dilutive securities excluded from earnings per share		5,178		701		6,744	877
Earnings Per Share Reconciliation [Abstract]
Net loss		$ (222,995)	$ (251,269)	$ (89,252)	$ (411,895)	$ (474,264)	$ (501,147)
Basic weighted-average common shares outstanding		118,357		113,008		116,568	113,015
Dilutive effect of non-vested RSUs and contingent PSUs		0		0		0	0
Dilutive effect of warrants		0		0		0	0
Diluted weighted-average common shares outstanding		118,357		113,008		116,568	113,015
Basic net loss per common share		$ (1.88)		$ (0.79)		$ (4.07)	$ (4.43)
Diluted net loss per common share		$ (1.88)		$ (0.79)		$ (4.07)	$ (4.43)