Senior secured notes, convertible notes, and corporate debt, net (Details)							12 Months Ended
	Dec. 21, 2021 USD ($)	Oct. 20, 2021 USD ($)	Mar. 25, 2021	Feb. 10, 2021 USD ($)	Jul. 22, 2019 USD ($)	Aug. 09, 2017 USD ($) $ / shares	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($) item	Dec. 31, 2020 USD ($)	Dec. 02, 2019 USD ($)	Apr. 27, 2018	Apr. 17, 2018 USD ($)	Jan. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Senior secured notes, Convertible notes, and Corporate debt
Total Senior secured notes, net							$ 342,035,000	$ 342,035,000	$ 342,035,000	$ 342,035,000	$ 179,659,000
Total Corporate debt, net							441,817,000	441,817,000	441,817,000	441,817,000	150,989,000
Total Convertible notes, net							113,247,000	113,247,000	113,247,000	113,247,000	$ 112,129,000
Total carrying amount of debt components							897,099,000	897,099,000	897,099,000	897,099,000
Total carrying amount of conversion option of equity components recorded in equity							642,000	642,000	642,000	642,000
Contractual maturities of the Senior Secured Notes, Convertible Notes, and Corporate debt
2023							115,000,000	115,000,000	115,000,000	115,000,000
2026							655,500,000	655,500,000	655,500,000	655,500,000
Thereafter							146,250,000	146,250,000	146,250,000	146,250,000
Total contractual amounts							916,750,000	916,750,000	916,750,000	916,750,000
Unamortized deferred financing costs, discounts, and premiums, net							(19,651,000)	(19,651,000)	(19,651,000)	(19,651,000)
Total carrying amount of debt components							897,099,000	897,099,000	897,099,000	897,099,000
Convertible Notes
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value						$ 115,000,000.0	$ 115,000,000	$ 115,000,000	$ 115,000,000	$ 115,000,000
Interest rate (as a percent)						7.00%	7.00%	7.00%	7.00%	7.00%
Conversion ratio						1.6253
Principal amount of notes for conversion						$ 25
Initial conversion price | $ / shares						$ 15.38
Principal amount of the notes to be redeemed (as a percent)						100.00%
Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instruments must exceed threshold percentage for a specified number of trading days to trigger conversion feature								30		30
Threshold period of specified consecutive trading days within which the common stock price, used in a calculation with with the conversion rate, the result of which must exceed the threshold percentage							5 days
Specified period of time used to calculate average closing market price of common stock to be used as a factor in determining potential trigger of conversion feature							10 days
Gross carrying value of convertible notes						$ 112,700,000
Gross carrying value of the equity component						$ 2,300,000
Unamortized discount							$ (642,000)	$ (642,000)	$ (642,000)	$ (642,000)
Unamortized deferred financing costs							(1,111,000)	(1,111,000)	(1,111,000)	(1,111,000)
Total Corporate debt, net							113,247,000	113,247,000	$ 113,247,000	$ 113,247,000
Convertible Notes | Minimum
Senior secured notes, Convertible notes, and Corporate debt
Percentage of common stock price to conversion price of convertible debt instruments to determine eligibility of conversion									120.00%
Threshold number of specified trading days that common stock price to conversion price of convertible debt instruments must exceed threshold percentage within a specified consecutive trading period to trigger conversion feature | item										20
The threshold percentage that per share value of distributions exceeds the average market price which may trigger the conversion feature									10.00%
Convertible Notes | Maximum
Senior secured notes, Convertible notes, and Corporate debt
Threshold percentage of the trading price of the convertible debt instrument to the product of the conversion rate and the closing stock price during any five consecutive trading day period									98.00%
Corporate Debt
Senior secured notes, Convertible notes, and Corporate debt
Unamortized discount							(6,541,000)	(6,541,000)	$ (6,541,000)	$ (6,541,000)
Unamortized deferred financing costs							(3,392,000)	(3,392,000)	(3,392,000)	(3,392,000)
Total carrying amount of debt components							441,817,000	441,817,000	441,817,000	441,817,000
Contractual maturities of the Senior Secured Notes, Convertible Notes, and Corporate debt
Total carrying amount of debt components							441,817,000	441,817,000	441,817,000	441,817,000
6.20% Senior Notes due 2026
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value					$ 57,500,000		$ 104,250,000	$ 104,250,000	$ 104,250,000	$ 104,250,000		$ 45,000,000.0
Interest rate (as a percent)					6.20%		6.20%	6.20%	6.20%	6.20%
Proceeds from secured debt facilities					$ 55,300,000
Principal amount of the notes to be redeemed (as a percent)					100.00%
Debt redemption price percentage					101.00%
Proceeds from note offerings					$ 55,300,000
6.20% Senior Notes due 2026 | Over-allotment option
Senior secured notes, Convertible notes, and Corporate debt
Proceeds from secured debt facilities					7,500,000
Proceeds from note offerings					$ 7,500,000
5.75% Senior Notes Due 2026
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value				$ 201,300,000			$ 201,250,000	$ 201,250,000	$ 201,250,000	$ 201,250,000
Interest rate (as a percent)				5.75%			5.75%	5.75%	5.75%	5.75%
Proceeds from secured debt facilities				$ 195,200,000
Principal amount of the notes to be redeemed (as a percent)				100.00%
Debt redemption price percentage				101.00%
Proceeds from note offerings				$ 195,200,000
5.75% Senior Notes Due 2026 | Over-allotment option
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value				$ 26,300,000
6.50% Senior Notes due 2021
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value														$ 50,000,000
Interest rate (as a percent)													6.50%
Principal amount of the notes to be redeemed (as a percent)			100.00%
4.50% Senior Secured Notes Due 2026
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value							$ 350,000,000	$ 350,000,000	$ 350,000,000	$ 350,000,000
Interest rate (as a percent)							4.50%	4.50%	4.50%	4.50%
Unamortized deferred financing costs							$ (7,965,000)	$ (7,965,000)	$ (7,965,000)	$ (7,965,000)
Total Senior secured notes, net							342,035,000	342,035,000	342,035,000	342,035,000
Junior Subordinated I-A Notes
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value							15,000,000	15,000,000	$ 15,000,000	15,000,000
Junior Subordinated I-A Notes | Three Month LIBOR
Senior secured notes, Convertible notes, and Corporate debt
Pricing, spread on variable (as a percent)									3.10%
Junior Subordinated I-B Notes
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value							21,250,000	21,250,000	$ 21,250,000	21,250,000
Junior Subordinated I-B Notes | Three Month LIBOR
Senior secured notes, Convertible notes, and Corporate debt
Pricing, spread on variable (as a percent)									3.10%
5.50% Senior Notes due 2028
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value	$ 110,000,000.0						$ 110,000,000	$ 110,000,000	$ 110,000,000	$ 110,000,000
Interest rate (as a percent)	5.50%						5.50%	5.50%	5.50%	5.50%
Proceeds from secured debt facilities	$ 107,400,000
Debt redemption price percentage	101.00%
Proceeds from note offerings	$ 107,400,000
5.50% Senior Notes due 2028 | 2024
Senior secured notes, Convertible notes, and Corporate debt
Principal amount of the notes to be redeemed (as a percent)	102.75%
5.50% Senior Notes due 2028 | 2025
Senior secured notes, Convertible notes, and Corporate debt
Principal amount of the notes to be redeemed (as a percent)	101.375%
5.50% Senior Notes due 2028 | 2026
Senior secured notes, Convertible notes, and Corporate debt
Principal amount of the notes to be redeemed (as a percent)	100.6875%
5.50% Senior Notes due 2028 | 2027 and thereafter
Senior secured notes, Convertible notes, and Corporate debt
Principal amount of the notes to be redeemed (as a percent)	100.00%
ReadyCap Holdings LLC | 7.50% Senior Secured Notes Due 2022
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value															$ 40,000,000.0	$ 140,000,000.0
Interest rate (as a percent)															7.50%	7.50%
Yield-to-maturity (as a percent)															6.50%
ReadyCap Holdings | 4.50% Senior Secured Notes Due 2026
Senior secured notes, Convertible notes, and Corporate debt
Debt instrument, face value		$ 350,000,000.0
Interest rate (as a percent)		4.50%
Proceeds from secured debt facilities		$ 341,800,000
Principal amount of the notes to be redeemed (as a percent)		100.00%
Proceeds from note offerings		$ 341,800,000