Commercial Loans - Narrative (Details) $ in Thousands		1 Months Ended	12 Months Ended
	Sep. 15, 2021 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2021 USD ($) entity	Sep. 24, 2021 USD ($)	Jul. 07, 2021 USD ($)	Feb. 24, 2021 USD ($)	Dec. 31, 2020 USD ($)
Variable Interest Entity [Line Items]
Variable interest entity, amount acquired, interest rate			8.80%
Principal balance			$ 2,572,727
VIE, consolidated, number of commercial loan trusts | entity			2
Real estate owned			$ 42,500
Members' interest			$ 11,200
Number of VIEs, as primary beneficiary | entity			1
RETL Trust Securitized Commercial Loan, at Fair Value (1)
Variable Interest Entity [Line Items]
Principal balance			$ 0				$ 354,202
Gross unrealized losses			0				$ (14,998)
CSMC Trust | Class F | Secured Debt
Variable Interest Entity [Line Items]
Debt default, amount			$ 14,900
SBC Two
Variable Interest Entity [Line Items]
Principal Amount Outstanding of Loans Held-in-portfolio				$ 9,200
CSMC Trust
Variable Interest Entity [Line Items]
Debt instrument, basis spread on variable rate			4.38%
Securitized Commercial Loans
Variable Interest Entity [Line Items]
Coupon rate			59.70%
COVID response, borrowers requesting forbearance, principal balance						$ 30,000
Securitized Commercial Loans | RETL Trust Securitized Commercial Loan, at Fair Value (1)
Variable Interest Entity [Line Items]
Variable interest entity, amount acquired		$ 65,300
Variable interest entity, amount acquired, eligible risk retention	$ 45,300	$ 45,300
Eligible risk retention percentage		5.00%
Securitized Commercial Loans | CSMC Trust
Variable Interest Entity [Line Items]
Principal balance			$ 1,400,000
Securitized Commercial Loans | RSBC Trust Commercial Loans, at Fair Value
Variable Interest Entity [Line Items]
Principal balance			14,362
Securitized Commercial Loans | RSBC Trust Commercial Loans, at Fair Value | SBC 3
Variable Interest Entity [Line Items]
Principal balance					$ 45,200
Commercial Loans
Variable Interest Entity [Line Items]
Principal balance			$ 192,159
VIE, consolidated, number of commercial loan trusts | entity			2
Commercial Loans | CRE 3 | Retail
Variable Interest Entity [Line Items]
Principal balance			$ 90,000
Loss on investment			$ 29,100