Repurchase Agreements, Loan Participations Sold, Notes Payable and Secured Term Loan, Net - Summary of Liability Under Repurchase Agreements (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021		Dec. 31, 2020
Repurchase Agreement Counterparty [Line Items]
Carrying value		$ 167,744	[1]	$ 516,484	[2]
Loan held by company		420,844	[1]	888,232	[2]
Repurchase Agreements
Repurchase Agreement Counterparty [Line Items]
Par Value		3,489,511	[3]	2,685,203	[4]
Carrying value		3,489,511	[3]	2,685,203	[4]
Loan held by company		$ 5,336,756	[3]	$ 4,410,882	[4]
Repurchase Agreements | JP Morgan Chase Bank NA Main Pool [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	1 year 7 months 6 days		1 year 6 months
Par Value		$ 1,173,280		$ 937,800
Carrying value		1,173,280		937,800
Loan held by company		$ 1,626,719		$ 1,549,663
Repurchase Agreements | JP Morgan Chase Bank NA Side Car [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	10 months 25 days
Par Value		$ 215,003
Carrying value		215,003
Loan held by company		$ 436,325
Repurchase Agreements | Morgan Stanley Bank NA [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	2 years 4 months 24 days		1 year 8 months 12 days
Par Value		$ 1,000,000		$ 844,283
Carrying value		1,000,000		844,283
Loan held by company		$ 1,709,758		$ 1,417,877
Repurchase Agreements | Goldman Sachs Bank USA [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	1 year 3 months 19 days		1 year 2 months 12 days
Par Value		$ 410,551		$ 578,015
Carrying value		410,551		578,015
Loan held by company		$ 589,825		$ 961,148
Repurchase Agreements | Barclays Bank PLC [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	1 year 4 months 24 days		1 year 9 months 18 days
Par Value		$ 193,884		$ 201,384
Carrying value		193,884		201,384
Loan held by company		$ 283,716		$ 277,948
Repurchase Agreements | Deutsche Bank AG New York Branch [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	2 years 3 months 19 days
Par Value		$ 211,372
Carrying value		211,372
Loan held by company		$ 327,671
Repurchase Agreements | Wells Fargo Bank NA [Member]
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]	2 years 9 months 18 days
Par Value		$ 285,421
Carrying value		285,421
Loan held by company		$ 362,742
Repurchase Agreements | Societe Generale New York Branch
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]			1 year 9 months 18 days
Par Value				$ 50,000
Carrying value				50,000
Loan held by company				$ 97,262
Repurchase Agreements | Deutsche Bank A G Cayman Island Branch
Repurchase Agreement Counterparty [Line Items]
Weighted Average Term (1)	[5]			2 years 8 months 12 days
Par Value				$ 73,721
Carrying value				73,721
Loan held by company				$ 106,984

[1] This financing has a LIBOR floor of 1.85%.

[2] Weighted average interest rate as of December 31, 2020 was 5.09%. Weighted average is based on outstanding principal as of December 31, 2020.

[3] Weighted average interest rate as of December 31, 2021 was LIBOR plus 2.16%. One-month LIBOR as of December 31, 2021 was 0.10%. Weighted average is based on outstanding principal as of December 31, 2021.

[4] Weighted average interest rate as of December 31, 2020 was LIBOR plus 2.17%. One-month LIBOR as of December 31, 2020 was 0.14%. Weighted average is based on outstanding principal as of December 31, 2020.

[5] The weighted average term (years) is determined based on the contractual maturity date of the corresponding loans collateralizing each facility.