Loans Held for Investment and Loans Held for Investment at Fair Value - Additional Information (Details) - USD ($)	12 Months Ended			33 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Accounts Notes And Loans Receivable [Line Items]
Accrued interest income recognized on nonaccrual loans	$ 0	$ 0
Cash basis interest income recognized on nonaccrual loans	27,300,000	31,200,000
Average recorded investment of individually evaluated loans, computed using month-end balances	$ 269,400,000	$ 311,200,000
Recovery rate on long-term nonperforming assets	106.70%	104.20%	103.10%
Recovery rate on short-term nonperforming assets	107.00%	102.70%
COVID-19
Accounts Notes And Loans Receivable [Line Items]
Loans	$ 203,300,000	$ 296,000,000.0		$ 203,300,000
90+days
Accounts Notes And Loans Receivable [Line Items]
Annualized charge rate of non performing loans	0.20%	0.42%	0.65%
COVID 19 Forbearance Program
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment	$ 292,400,000			292,400,000
Loans held for investment forbearance period	90 days
Amount of loan granted for unusual risk forbearance	$ 215,800,000		$ 409,600,000	$ 215,800,000
Loans held for investment unpaid principal balance performing and accruing, percentage	80.30%	79.80%		80.30%
Loans held for investment unpaid principal balance nonperforming and nonaccrual percentage	19.70%	20.20%		19.70%
Accrued interest income recognized on nonaccrual loans	$ 4,300,000			$ 11,500,000