Long Term Debt - Schedule of Aggregate Principal Balance and Fair Value of Finance Receivables Pledged to Securitization Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Asset Pledged as Collateral without Right
Debt Instrument [Line Items]
Aggregate Principal Balance	$ 517,569	$ 361,609
Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair Value	446,252	316,998
United Auto Credit 2021-1 | Asset Pledged as Collateral without Right
Debt Instrument [Line Items]
Aggregate Principal Balance		38,951
United Auto Credit 2021-1 | Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair Value		35,790
United Auto Credit 2022-2 | Asset Pledged as Collateral without Right
Debt Instrument [Line Items]
Aggregate Principal Balance	77,932	125,072
United Auto Credit 2022-2 | Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair Value	66,070	111,379
United Auto Credit 2023-1 | Asset Pledged as Collateral without Right
Debt Instrument [Line Items]
Aggregate Principal Balance	126,289	197,586
United Auto Credit 2023-1 | Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair Value	103,178	$ 169,829
United Auto Credit 2024-1 | Asset Pledged as Collateral without Right
Debt Instrument [Line Items]
Aggregate Principal Balance	313,348
United Auto Credit 2024-1 | Asset Pledged as Collateral with Right
Debt Instrument [Line Items]
Fair Value	$ 277,004