Loans Held for Investment and Loans Held for Investment at Fair Value - Schedule of Loans Held for Investment Pledged as Collateral for Warehouse Facility Agreements and Securitizations Issued (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accounts Notes And Loans Receivable [Line Items]
Total	$ 3,075,047	$ 2,172,766
Asset Pledged as Collateral without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	418,749	400,759
2013 Repurchase Agreement | Asset Pledged as Collateral without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	170,185	202,511
2021 Repurchase Agreement | Asset Pledged as Collateral without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	101,024	114,072
Bank Credit Agreement | Asset Pledged as Collateral without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	39,087	30,959
2021 Term Repurchase Agreement | Asset Pledged as Collateral without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	104,594	53,217
July 2021 Term Repurchase Agreement | Asset Pledged as Collateral without Right
Accounts Notes And Loans Receivable [Line Items]
Total pledged loans	3,859
2015-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total		31,931
2016-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	39,720	52,623
2017-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	67,048	94,809
2018-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	48,139	71,051
2018-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	104,791	154,974
2019-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	104,249	144,727
2019-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	91,025	132,358
2019-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	75,618	103,266
2020-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	144,913	189,547
2020-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	81,259	98,403
2020-MC1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total		134,957
2021-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	208,875	249,396
2021-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	172,144	198,039
2021-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	178,861	202,138
2021-4 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	275,741	$ 314,547
2022-1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	262,526
2022-2 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	245,339
2022-MC1 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	97,246
2022-3 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	299,638
2022-4 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	326,627
2022-5 Trust
Accounts Notes And Loans Receivable [Line Items]
Total	$ 251,288