Borrowings - Assets Pledged as Collateral (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Schedule of Borrowings [Line Items]
Outstanding borrowings	$ 940,428	$ 997,702
Restricted cash pledged as collateral	66,221	110,056
Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Restricted cash pledged as collateral	11,435	13,147
ULT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings	91,479	163,773
ULT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary | Asset Pledged as Collateral
Schedule of Borrowings [Line Items]
Aggregate outstanding principal of loans pledged as collateral	123,381	228,895
Aggregate fair value of loans purchased and held by UAWT	126,622	256,024
Restricted cash pledged as collateral	4,904	8,547
UAWT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings	187,699	172,679
Aggregate outstanding principal of loans pledged as collateral	272,094	221,847
Aggregate fair value of loans purchased and held by UAWT	268,117	216,539
Restricted cash pledged as collateral	$ 383	$ 843