Basis of Presentation (Antidilutive Securities) (Details) - shares shares in Thousands			3 Months Ended		9 Months Ended
	Sep. 30, 2020		Sep. 18, 2020	Sep. 30, 2019	Sep. 18, 2020	Sep. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issuable upon exercise of series A and B warrants	5,500
Stock appreciation rights
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		0	2,011	1,007	2,043
Restricted stock and performance-based equity awards
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		165	7,996	7,280	5,859
Convertible senior notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0		82,445	0	87,888	0
Warrants
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	5,526	[1]	0	0	0	0

[1] Shares shown under “warrants” represent the impact over the Successor periods of the approximately 5.5 million shares of the Successor’s common stock issuable upon full exercise of the series A and series B warrants which were issued pursuant to the Plan to the Predecessor’s convertible senior notes, senior subordinated notes, and equity holders.