Fair Value of Assets and Liabilities - Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022	Jun. 30, 2022
Assets:
Cash and cash equivalents	$ 48,716	$ 95,073	$ 587,861
Carrying Value
Assets:
Cash and cash equivalents	48,716	95,073
Restricted cash and investments	45,828	48,770
Liabilities:
Borrowings under exchange and senior credit facility	1,007,724	1,113,239
Fair Value
Assets:
Cash and cash equivalents	48,716	95,073
Restricted cash and investments	45,828	48,770
Liabilities:
Borrowings under exchange and senior credit facility	1,021,141	1,112,183
Level 1 | Fair Value
Assets:
Cash and cash equivalents	48,716	95,073
Restricted cash and investments	45,828	48,770
Level 2 | Fair Value
Liabilities:
Borrowings under exchange and senior credit facility	1,021,141	1,112,183
5.875% Senior Notes due 2024 | Carrying Value
Liabilities:
Senior notes, fair value	23,253	23,253
5.875% Senior Notes due 2024 | Fair Value
Liabilities:
Senior notes, fair value	22,712	22,997
5.875% Senior Notes due 2024 | Level 2 | Fair Value
Liabilities:
Senior notes, fair value	22,712	22,997
10.500% Public Second Lien Notes due 2028 | Carrying Value
Liabilities:
Senior notes, fair value	286,521	286,521
10.500% Public Second Lien Notes due 2028 | Fair Value
Liabilities:
Senior notes, fair value	288,679	291,610
10.500% Public Second Lien Notes due 2028 | Level 2 | Fair Value
Liabilities:
Senior notes, fair value	288,679	291,610
9.500% Private Second Lien Notes due 2028
Liabilities:
Senior notes, fair value	239,142	239,142
9.500% Private Second Lien Notes due 2028 | Fair Value
Liabilities:
Senior notes, fair value	235,555	232,627
9.500% Private Second Lien Notes due 2028 | Level 2 | Fair Value
Liabilities:
Senior notes, fair value	235,555	232,627
6.00% Senior Notes due 2026 | Carrying Value
Liabilities:
Senior notes, fair value	110,858	110,858
6.00% Senior Notes due 2026 | Fair Value
Liabilities:
Senior notes, fair value	102,197	99,132
6.00% Senior Notes due 2026 | Level 2 | Fair Value
Liabilities:
Senior notes, fair value	102,197	99,132
6.50% Exchangeable Senior Notes due 2026 | Carrying Value
Liabilities:
Senior notes, fair value	230,000	230,000
6.50% Exchangeable Senior Notes due 2026 | Fair Value
Liabilities:
Senior notes, fair value	258,622	327,872
6.50% Exchangeable Senior Notes due 2026 | Level 2 | Fair Value
Liabilities:
Senior notes, fair value	$ 258,622	$ 327,872