Debt - Summary of Detail Comprising Debt and Related Book Values (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total debt, before discount and deferred financing cost	$ 1,121,060	$ 993,314
Discount and deferred financing cost	(71,695)	(7,802)
Total debt, net of discount and deferred financing costs	1,049,365	985,512
Senior Notes | 12.00% Second-Priority Senior Secured Notes – due January 2026
Debt Instrument [Line Items]
Total debt, before discount and deferred financing cost	650,000
Senior Notes | 11.00% Second-Priority Senior Secured Notes – due April 2022
Debt Instrument [Line Items]
Total debt, before discount and deferred financing cost		347,254
Senior Notes | 7.50% Senior Notes – due May 2022
Debt Instrument [Line Items]
Total debt, before discount and deferred financing cost	6,060	6,060
Bank Credit Facility | Bank Credit Facility – matures May 2022
Debt Instrument [Line Items]
Total debt, before discount and deferred financing cost	$ 465,000	$ 640,000