Nature of Ops and Sign. Acctg Policies (Reconciliation of Weighted Average Shares Table) (Details 3) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Sep. 18, 2020	Dec. 31, 2021	Dec. 31, 2019
Numerator
Net income (loss) - basic	$ (50,658)	$ (1,432,578)	$ 56,002	$ 216,959
Interest on convertible senior notes including amortization of discount, net of tax	0	0	0	14,134
Net income (loss) - diluted	$ (50,658)	$ (1,432,578)	$ 56,002	$ 231,093
Denominator
Weighted average common shares outstanding – basic	50,000	495,560	50,918	459,524
Restricted stock units	0	0	762	0
Warrants	0	0	2,138	0
Restricted stock and performance-based equity awards	0	0	0	2,396
Convertible senior notes	0	0	0	48,421	[1]
Weighted average common shares outstanding – diluted	50,000	495,560	53,818	510,341
Predecessor common shares issuable upon full conversion of convertible senior notes				90,900

[1] For the year ended December 31, 2019, shares shown under “convertible senior notes” represent the prorated portion 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 (see Note 8, Long-Term Debt – 2019 Predecessor Debt Reduction Transactions).