Variable Interest Entities - Narrative (Details)	12 Months Ended
	Dec. 31, 2021 USD ($) loans collateralizedLoanObligation	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Variable interest entities
Number of CLOs | collateralizedLoanObligation	3
Number of SASBs | loans	1
Assets	$ 83,850,397,000	$ 80,873,509,000
Liabilities	77,201,590,000	76,010,933,000
Temporary equity	214,915,000	0	$ 0	$ 0
Investments in unconsolidated entities	$ 90,097,000	$ 108,054,000
CMBS JV
Variable interest entities
Ownership percentage	51.00%
Primary beneficiary
Variable interest entities
Assets	$ 102,400,000
Liabilities	53,500,000
Primary beneficiary | CMBS Venture Holdings
Variable interest entities
Assets	331,700,000
Liabilities	73,900,000
Primary beneficiary | SPT Dolphin
Variable interest entities
Assets	1,000,000,000
Liabilities	0
Primary beneficiary | Woodstar Feeder Fund, L.P.
Variable interest entities
Assets	300,000,000
Liabilities	0
Temporary equity	200,000,000
Not primary beneficiary
Variable interest entities
Maximum risk of loss related to VIEs, on fair value basis	22,200,000
Not primary beneficiary | Measurement Period Adjustments
Variable interest entities
Investments in unconsolidated entities	24,500,000
Not primary beneficiary | Securitization SPEs
Variable interest entities
Long term debt, gross	$ 4,900,000,000