Real Estate Securities - Narrative (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2022 USD ($) securitizationTrust	Jun. 30, 2021 USD ($)	Dec. 31, 2022 USD ($) securitizationTrust	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($)
Debt Securities, Available-for-sale [Line Items]
Number of securitization trusts held (in securitization trusts) | securitizationTrust	1		1
Proceeds from sale of securitization trust	$ 36,900	$ 28,700
Unrealized gain	900
Realized loss in earnings	(900)	(19,500)	$ (854)	$ (36,623)	$ 0
Unrealized (gain) loss on mortgage loans and obligations held in securitization trusts, net		(19,500)	854	41,904	(50,521)
Interest payable	11,680		11,680	11,076
Other Nonoperating Income (Expense)
Debt Securities, Available-for-sale [Line Items]
Realized loss in earnings			1,400
Primary beneficiary, securitization trust
Debt Securities, Available-for-sale [Line Items]
Realized loss in earnings				(17,100)
Interest payable	300	2,800	300
Gross assets	682,800	830,900
Gross liabilities	646,600	802,200
Accrued interest receivable	300	$ 3,000	300
Primary beneficiary
Debt Securities, Available-for-sale [Line Items]
Unrealized gain	854
Realized loss in earnings			(854)	(36,623)	0
Unrealized (gain) loss on mortgage loans and obligations held in securitization trusts, net				41,904	$ (50,521)
Mortgage loans held in trust, unpaid principal balance				783,800
Mortgage obligations held in trust, unpaid principal balance				$ 681,200
Number of underlying mortgage loans (in loans) | loan				62
Difference between held and issued mortgage loans in securitization trusts	$ 36,200		$ 36,200	$ 36,200
Weighted average coupon (in percentage)				4.90%
Weighted average loan to value ratio (in percentage)				60.70%