Multi-family Loans, at Fair Value - Narrative (Details) - USD ($)	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Loan premiums, early redemption	$ 128,000	$ 1,356,000	$ 315,000	$ 3,839,000
Multi-family loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Unrealized gains (losses)	(16,800)	(2,500,000)	900,000	(3,000,000)
Loan premiums, early redemption	$ 0	$ 7,100	$ 200,000	$ 1,000,000

$ 128,000

$ 1,356,000

$ 315,000

$ 3,839,000

$ 0

$ 7,100

$ 200,000

$ 1,000,000