Loans Held for Investment and Loans Held for Investment at Fair Value - Summary of UPB and Amortized Cost Basis of Loans in COVID-19 Forbearance Program (Details) - COVID 19 Forbearance Program - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Accounts Notes And Loans Receivable [Line Items]
UPB Beginning balance	$ 292,429	$ 392,073
UPB Additions		2,616
UPB Foreclosures	(3,593)	(402)
UPB Repayments	(87,831)	(101,858)
UPB Ending balance	201,005	292,429
UPB Performing/Accruing, Amount	161,455	233,307
UPB Nonperforming/Nonaccrual, Amount	$ 39,550	$ 59,122
UPB Performing/Accruing, Percentage	80.30%	79.80%
UPB Nonperforming/Nonaccrual, Percentage	19.70%	20.20%
Amortized Cost Beginning balance	$ 295,990	$ 396,918
Amortized Cost Additions		2,615
Amortized Cost Foreclosures	(3,620)	(408)
Amortized Cost Repayments	(89,024)	(103,135)
Amortized Cost Ending balance	203,346	295,990
Amortized Cost Performing/Accruing, Amount	163,346	236,076
Amortized Cost Nonperforming/Nonaccrual, Amount	$ 40,000	$ 59,914
Amortized Cost Performing/Accruing, Percentage	80.30%	79.80%
Amortized Cost Nonperforming/Nonaccrual, Percentage	19.70%	20.20%