Loans Held for Investment and Loans Held for Investment at Fair Value - Additional Information (Details) - USD ($)	12 Months Ended			45 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2023	Dec. 31, 2020
Accounts Notes And Loans Receivable [Line Items]
Accrued interest income recognized on nonaccrual loans	$ 0	$ 0
Cash basis interest income recognized on nonaccrual loans	30,600,000	27,300,000
Average recorded investment of individually evaluated loans, computed using month-end balances	331,400,000	269,400,000
COVID-19
Accounts Notes And Loans Receivable [Line Items]
Loans	$ 176,500,000	$ 203,300,000		$ 176,500,000
90+days
Accounts Notes And Loans Receivable [Line Items]
Annualized charge rate of non performing loans	0.62%	0.20%	0.42%
COVID 19 Forbearance Program
Accounts Notes And Loans Receivable [Line Items]
Loans held for investment	$ 201,000,000	$ 292,400,000	$ 394,700,000	201,000,000
Loans held for investment forbearance period	90 days
Amount of loan granted for unusual risk forbearance	$ 241,700,000			$ 241,700,000	$ 411,700,000
Loans held for investment unpaid principal balance performing and accruing, percentage	75.80%	80.30%		75.80%
Loans held for investment unpaid principal balance nonperforming and nonaccrual percentage	24.20%	19.70%		24.20%
Accrued interest income recognized on nonaccrual loans	$ 4,800,000			$ 13,600,000