Basis of Presentation (Reconciliation of Net Income (Loss) and Weighted Average Shares Table) (Details) shares in Thousands, $ in Thousands		3 Months Ended							9 Months Ended
	Sep. 30, 2020 USD ($) shares	Sep. 18, 2020 USD ($) shares	Jun. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Sep. 30, 2019 USD ($) shares		Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 18, 2020 USD ($) shares	Sep. 30, 2019 USD ($) shares
Numerator
Net income (loss) - basic | $	$ 2,758	$ (809,120)	$ (697,474)	$ 74,016	$ 72,862		$ 146,692	$ (25,674)	$ (1,432,578)	$ 193,880
Interest on convertible senior notes including amortization of discount, net of tax | $	0	0			5,101				0	5,649
Net income (loss) - diluted | $	$ 2,758	$ (809,120)			$ 77,963				$ (1,432,578)	$ 199,529
Denominator
Weighted average common shares outstanding - basic	50,000	497,398			455,487				495,560	453,287
Restricted stock and performance-based equity awards	0	0			865				0	2,489
Convertible senior notes	0	0			90,853	[1]			0	34,278
Weighted average common shares outstanding - diluted	50,000	497,398			547,205				495,560	490,054
Predecessor common shares issuable upon conversion of convertible senior notes					90,900					90,900

[1] hares shown under “convertible senior notes” represent the impact over the Predecessor periods of the approximately 90.9 million shares of the Predecessor’s common stock issuable upon full conversion of the convertible senior notes which were issued on June 19, 2019.