Borrowings - Assets Pledged as Collateral (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule of Borrowings [Line Items]
Outstanding borrowings	$ 1,011,413	$ 997,702
Restricted cash pledged as collateral	64,917	110,056
Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Restricted cash pledged as collateral	18,401	13,147
ULT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings	151,733	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	210,383	228,895
Aggregate fair value of loans purchased and held by UAWT	253,336	256,024
Restricted cash pledged as collateral	10,962	8,547
UAWT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings	198,430	172,679
Aggregate outstanding principal of loans pledged as collateral	298,158	221,847
Aggregate fair value of loans purchased and held by UAWT	291,621	216,539
Restricted cash pledged as collateral	$ 490	$ 843