Long Term Debt - Schedule of Securitization Debt of Consolidated VIEs (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($)
Debt Instrument [Line Items]
Initial Principal	$ 339,660
Outstanding Principal	206,991
Fair Value	$ 204,627
United Auto Credit 2020-1-C
Debt Instrument [Line Items]
Final Scheduled Payment Date	Feb. 10, 2025
Initial Principal	$ 32,780
Contractual Interest Rate	2.15%
Outstanding Principal	$ 10,748
Fair Value	$ 10,750
United Auto Credit 2020-1-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Feb. 10, 2025
Initial Principal	$ 31,450
Contractual Interest Rate	2.88%
Outstanding Principal	$ 31,450
Fair Value	$ 31,532
United Auto Credit 2020-1-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Feb. 10, 2025
Initial Principal	$ 18,730
Contractual Interest Rate	5.19%
Outstanding Principal	$ 18,730
Fair Value	$ 18,897
United Auto Credit 2020-1-F
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jan. 12, 2026
Initial Principal	$ 7,360
Contractual Interest Rate	9.08%
Outstanding Principal	$ 7,360
Fair Value	$ 7,389
United Auto Credit 2021-1-A
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jul. 10, 2023
Initial Principal	$ 122,070
Contractual Interest Rate	0.34%
Outstanding Principal	$ 11,433
Fair Value	$ 11,422
United Auto Credit 2021-1-B
Debt Instrument [Line Items]
Final Scheduled Payment Date	Mar. 11, 2024
Initial Principal	$ 33,540
Contractual Interest Rate	0.68%
Outstanding Principal	$ 33,540
Fair Value	$ 33,382
United Auto Credit 2021-1-C
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 10, 2026
Initial Principal	$ 29,640
Contractual Interest Rate	0.84%
Outstanding Principal	$ 29,640
Fair Value	$ 29,228
United Auto Credit 2021-1-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 10, 2026
Initial Principal	$ 29,380
Contractual Interest Rate	1.14%
Outstanding Principal	$ 29,380
Fair Value	$ 28,560
United Auto Credit 2021-1-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 10, 2026
Initial Principal	$ 20,800
Contractual Interest Rate	2.58%
Outstanding Principal	$ 20,800
Fair Value	$ 19,962
United Auto Credit 2021-1-F
Debt Instrument [Line Items]
Final Scheduled Payment Date	Sep. 10, 2027
Initial Principal	$ 13,910
Contractual Interest Rate	4.30%
Outstanding Principal	$ 13,910
Fair Value	$ 13,505