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Senior Secured Notes (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jun. 17, 2020 USD ($)	May 05, 2020 USD ($)	Aug. 12, 2016 USD ($)
Senior Notes [Line Items]
Senior Notes, net	$ 2,121,319,000	$ 2,610,298,000
Permitted Second Lien Debt	1,000,000,000.0
Increase to Permitted Second Lien Debt					$ 827,500,000
Permitted Second Lien Debt, Remaining Borrowing Capacity	380,800,000
Senior Secured Notes
Senior Notes [Line Items]
Principal amount	512,160,000
Senior Notes, unamortized debt discount	39,771,000
Unamortized deferred financing costs	(11,733,000)
Senior Notes, net	$ 460,656,000	0
10.0% Senior Secured Notes due 2025 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	10.00%
Principal amount	$ 446,675,000	0		$ 446,700,000
Senior Notes, unamortized debt discount	37,943,000
Unamortized deferred financing costs	(11,558,000)
Senior Notes, net	397,174,000
Senior Notes debt issuance costs	$ 13,100,000
Debt Instrument, Senior Notes, Initial Fair Value				$ 405,000,000.0
1.50% Senior Secured Convertible Notes Due 2021 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	1.50%
Principal amount	$ 65,485,000	$ 0
Senior Notes, unamortized debt discount	1,828,000
Unamortized deferred financing costs	(175,000)
Senior Notes, net	63,482,000
Senior Convertible Notes, interest expense	$ 7,700,000
Senior Convertible Notes, conversion rate	24.6914
Senior Convertible Notes, principal amount of note	$ 1,000
Senior Convertible Notes, conversion price | $ / shares	$ 40.50
1.50% Senior Unsecured Convertible Notes Due 2021 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	1.50%	1.50%
Principal amount	$ 0	$ 172,500,000				$ 172,500,000
Senior Notes, unamortized debt discount		13,900,000
Unamortized deferred financing costs	0	(15,237,000)
Senior Notes, net	$ 0	157,263,000
Senior Notes debt issuance costs						$ 5,900,000
Senior Convertible Notes, interest expense		$ 11,000,000.0	$ 10,500,000

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