Loans Portfolio - Schedule of Loans and Financing Receivable (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2022 USD ($) Loan		Dec. 31, 2021 USD ($) Loan
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	$ 8,539,980	[1]	$ 7,488,611	[2]
Unpaid Principal Balance	7,080,932		6,441,238
Loans receivable held-for-investment	$ 7,038,246		$ 6,407,305
Number of Loans | Loan	72		59
Weighted Average Interest Rate(4)	5.35%	[3]	5.40%	[4]
Less: current expected credit loss reserve	$ (65,608)		$ (67,010)
Loans receivable held-for-investment, net	6,972,638		6,340,295
Variable Senior Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	8,219,356	[1],[5],[6]	7,163,032	[2],[7],[8]
Unpaid Principal Balance	6,763,623	[5],[6]	6,119,619	[7],[8]
Loans receivable held-for-investment	$ 6,720,583	[5],[6]	$ 6,085,351	[7],[8]
Variable Senior Loans | London Interbank Offered Rate (LIBOR)
Financing Receivable Recorded Investment Past Due [Line Items]
Number of Loans | Loan	64	[5],[6]	51	[7],[8]
Weighted Average Spread(2)	+ 4.02%	[5],[6],[9]	+ 4.06%	[7],[8],[10]
Weighted Average Interest Rate(4)	5.12%	[3],[5],[6]	5.16%	[4],[7],[8]
Variable Subordinate Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	$ 138,085	[1]	$ 137,079	[2]
Unpaid Principal Balance	134,770		133,119
Loans receivable held-for-investment	$ 135,258		$ 133,552
Variable Subordinate Loans | London Interbank Offered Rate (LIBOR)
Financing Receivable Recorded Investment Past Due [Line Items]
Number of Loans | Loan	3		3
Weighted Average Spread(2)	+ 10.59%	[9]	+ 10.38%	[10]
Weighted Average Interest Rate(4)	11.61%	[3]	11.37%	[4]
Variable Loan
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	$ 8,357,441	[1]	$ 7,300,111	[2]
Unpaid Principal Balance	6,898,393		6,252,738
Loans receivable held-for-investment	$ 6,855,841		$ 6,218,903
Variable Loan | London Interbank Offered Rate (LIBOR)
Financing Receivable Recorded Investment Past Due [Line Items]
Number of Loans | Loan	67		54
Weighted Average Spread(2)	+ 4.15%	[9]	+ 4.19%	[10]
Weighted Average Interest Rate(4)	5.25%	[3]	5.29%	[4]
Fixed Senior Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	$ 56,612	[1],[6]	$ 62,573	[2],[8]
Unpaid Principal Balance	56,612	[6]	62,573	[8]
Loans receivable held-for-investment	$ 56,770	[6]	$ 62,782	[8]
Number of Loans | Loan	3	[6]	3	[8]
Weighted Average Interest Rate(4)	10.41%	[3],[6]	10.09%	[4],[8]
Fixed Subordinate Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	$ 125,927	[1]	$ 125,927	[2]
Unpaid Principal Balance	125,927		125,927
Loans receivable held-for-investment	$ 125,635		$ 125,620
Number of Loans | Loan	2		2
Weighted Average Interest Rate(4)	8.49%	[3]	8.49%	[4]
Fixed Loan
Financing Receivable Recorded Investment Past Due [Line Items]
Loan Commitment(5)	$ 182,539	[1]	$ 188,500	[2]
Unpaid Principal Balance	182,539		188,500
Loans receivable held-for-investment	$ 182,405		$ 188,402
Number of Loans | Loan	5		5
Weighted Average Interest Rate(4)	9.09%	[3]	9.02%	[4]

[1] Loan commitment represents principal outstanding plus remaining unfunded loan commitments.

[2] Loan commitment represents principal outstanding plus unfunded loan commitments

[3] Reflects the weighted average interest rate based on the applicable floating benchmark rate (if applicable), including LIBOR/SOFR floors (if applicable). Weighted average is based on outstanding principal as of March 31, 2022 and includes loans on non-accrual status.

[4] Reflects the weighted average interest rate based on the applicable floating benchmark rate (if applicable), including LIBOR floors (if applicable). Weighted average is based on outstanding principal as of December 31, 2021

[5] Includes a fixed rate loan with an outstanding principal balance of $37.9 million and a loan commitment of $39.7 million at March 31, 2022, which shares the same collateral as floating rate loans with an outstanding principal balance of $31.8 million and a loan commitment of $32.6 million at March 31, 2022

[6] Senior loans include senior mortgages and similar loans, including related contiguous subordinate loans (if any), and pari passu participations in senior mortgage loans

[7] Includes a fixed rate loan with an outstanding principal balance of $33.5 million and a loan commitment of $39.7 million as of December 31, 2021, which shares the same collateral as floating rate loans with an outstanding principal balance of $103.1 million and a loan commitment of $104.4 million at December 31, 2021.

[8] Senior loans include senior mortgages and similar loans, including related contiguous subordinate loans (if any), and pari passu participations in senior mortgage loans.

[9] The weighted average spread is expressed as a spread over the relevant floating benchmark rates. One-month LIBOR as of March 31, 2022 was 0.45%. One-month SOFR as of March 31, 2022 was 0.30%.  Weighted average is based on outstanding principal as of March 31, 2022

[10] The weighted average spread is expressed as a spread over the relevant floating benchmark rates. One-month LIBOR as of December 31, 2021 was 0.10%. Weighted average is based on outstanding principal as of December 31, 2021.