Borrowings - Assets Pledged as Collateral (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Schedule of Borrowings [Line Items]
Outstanding borrowings	$ 930,978,000	$ 709,787,000
Restricted cash	145,956,000	204,633,000
Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Restricted cash	31,602,000	79,561,000
ULT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings	100,523,000	48,030,000
ULT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary | Asset Pledged as Collateral
Schedule of Borrowings [Line Items]
Outstanding principal balance	147,221,000	76,865,000
Aggregate fair value of loans purchased and held by UAWT	153,799,000	142,687,000
Restricted cash	2,480,000	76,256,000
UAWT Warehouse Credit Facility | Revolving Credit Facility | Variable Interest Entity, Primary Beneficiary
Schedule of Borrowings [Line Items]
Outstanding borrowings	169,205,000	$ 0
Outstanding principal balance	250,294,000
Aggregate fair value of loans purchased and held by UAWT	254,277,000
Restricted cash	$ 874,000