Loans Held for Investment and Loans Held for Investment at Fair Value - Schedule of Loans Held for Investment Pledged as Collateral for Warehouse Facilities and Securitizations Issued (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Accounts Notes And Loans Receivable [Line Items]
Total	$ 3,538,653	$ 3,075,047
Asset Pledged as Collateral Without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	284,614	418,749
2013 Repurchase Agreement \| Asset Pledged as Collateral Without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	108,834	170,185
2021 Repurchase Agreement \| Asset Pledged as Collateral Without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	90,033	101,024
Bank Credit Agreement \| Asset Pledged as Collateral Without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	34,687	39,087
2021 Term Repurchase Agreement \| Asset Pledged as Collateral Without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	32,300	104,594
July 2021 Term Repurchase Agreement \| Asset Pledged as Collateral Without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	18,760	3,859
2016-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total		39,720
2017-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	53,046	67,048
2018-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	39,417	48,139
2018-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	88,773	104,791
2019-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	91,032	104,249
2019-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	76,091	91,025
2019-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	67,745	75,618
2020-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	122,479	144,913
2020-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	72,678	81,259
2021-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	187,743	208,875
2021-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	153,896	172,144
2021-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	164,120	178,861
2021-4 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	253,720	275,741
2022-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	249,184	262,526
2022-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	231,470	245,339
2022-MC1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	75,338	97,246
2022-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	283,716	299,638
2022-4 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	312,002	326,627
2022-5 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	236,366	$ 251,288
2023-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	223,410
2023-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	218,116
2023-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	260,389
2023-RTL1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	$ 77,922

Loans Held for Investment and Loans Held for Investment at Fair Value - Schedule of Loans Held for Investment Pledged as Collateral for Warehouse Facilities and Securitizations Issued (Details) - USD ($)
$ in Thousands