Long Term Debt - Schedule of Securitization Debt of Consolidated VIEs (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
United Auto Credit 2022-2-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jan. 10, 2028	Jan. 10, 2028
Initial Principal	$ 32,889	$ 32,889
Contractual Interest Rate	6.84%	6.84%
Outstanding Principal	$ 6,793	$ 11,415
Fair Value	$ 6,804	$ 11,400
United Auto Credit 2022-2-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Apr. 10, 2029	Apr. 10, 2029
Initial Principal	$ 33,440	$ 33,440
Contractual Interest Rate	10.00%	10.00%
Outstanding Principal	$ 28,440	$ 28,440
Fair Value	$ 13,350	$ 13,011
United Auto Credit 2023-1-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jul. 10, 2028	Jul. 10, 2028
Initial Principal	$ 35,653	$ 35,653
Contractual Interest Rate	8.00%	8.00%
Outstanding Principal	$ 12,743	$ 20,169
Fair Value	$ 12,860	$ 20,340
United Auto Credit 2023-1-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Sep. 10, 2029	Sep. 10, 2029
Initial Principal	$ 23,256	$ 23,256
Contractual Interest Rate	10.98%	10.98%
Outstanding Principal	$ 23,256	$ 23,256
Fair Value	$ 24,421	$ 24,770
United Auto Credit 2024-1-C
Debt Instrument [Line Items]
Final Scheduled Payment Date	Oct. 10, 2029	Oct. 10, 2029
Initial Principal	$ 35,190	$ 35,190
Contractual Interest Rate	7.06%	7.06%
Outstanding Principal	$ 6,697	$ 23,664
Fair Value	$ 6,701	$ 23,721
United Auto Credit 2024-1-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Nov. 12, 2029	Nov. 12, 2029
Initial Principal	$ 52,160	$ 52,160
Contractual Interest Rate	8.30%	8.30%
Outstanding Principal	$ 52,160	$ 52,160
Fair Value	$ 52,849	$ 52,953
United Auto Credit 2024-1-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Nov. 12, 2030	Nov. 12, 2030
Initial Principal	$ 37,540	$ 37,540
Contractual Interest Rate	10.45%	10.45%
Outstanding Principal	$ 37,540	$ 37,540
Fair Value	$ 39,278	$ 39,263
United Auto Credit 2025-1-A
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 10, 2027	Jun. 10, 2027
Initial Principal	$ 138,300	$ 138,300
Contractual Interest Rate	4.80%	4.80%
Outstanding Principal	$ 9,062	$ 37,290
Fair Value	$ 9,063	$ 37,324
United Auto Credit 2025-1-B
Debt Instrument [Line Items]
Final Scheduled Payment Date	Feb. 10, 2028	Feb. 10, 2028
Initial Principal	$ 50,450	$ 50,450
Contractual Interest Rate	5.05%	5.05%
Outstanding Principal	$ 50,450	$ 50,450
Fair Value	$ 50,516	$ 50,642
United Auto Credit 2025-1-C
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 10, 2030	Jun. 10, 2030
Initial Principal	$ 32,660	$ 32,660
Contractual Interest Rate	5.15%	5.15%
Outstanding Principal	$ 32,660	$ 32,660
Fair Value	$ 32,716	$ 32,849
United Auto Credit 2025-1-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jul. 10, 2030	Jul. 10, 2030
Initial Principal	$ 50,810	$ 50,810
Contractual Interest Rate	5.96%	5.96%
Outstanding Principal	$ 50,810	$ 50,810
Fair Value	$ 51,013	$ 51,166
United Auto Credit 2025-1-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Oct. 10, 2031	Oct. 10, 2031
Initial Principal	$ 35,560	$ 35,560
Contractual Interest Rate	7.71%	7.71%
Outstanding Principal	$ 35,560	$ 35,560
Fair Value	$ 35,613	35,805
United Auto Credit 2026-1-A
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 12, 2028
Initial Principal	$ 100,350
Contractual Interest Rate	4.41%
Outstanding Principal	$ 91,681
Fair Value	$ 91,653
United Auto Credit 2026-1-B
Debt Instrument [Line Items]
Final Scheduled Payment Date	May 10, 2029
Initial Principal	$ 40,130
Contractual Interest Rate	4.63%
Outstanding Principal	$ 40,130
Fair Value	$ 40,034
United Auto Credit 2026-1-C
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jun. 10, 2031
Initial Principal	$ 25,970
Contractual Interest Rate	5.06%
Outstanding Principal	$ 25,970
Fair Value	$ 25,869
United Auto Credit 2026-1-D
Debt Instrument [Line Items]
Final Scheduled Payment Date	Jul. 10, 2031
Initial Principal	$ 40,000
Contractual Interest Rate	5.65%
Outstanding Principal	$ 40,000
Fair Value	$ 39,820
United Auto Credit 2026-1-E
Debt Instrument [Line Items]
Final Scheduled Payment Date	Dec. 10, 2032
Initial Principal	$ 18,550
Contractual Interest Rate	7.77%
Outstanding Principal	$ 18,550
Fair Value	18,461
Total Rated Notes at Fair Value
Debt Instrument [Line Items]
Initial Principal	782,908	557,908
Outstanding Principal	562,502	403,414
Fair Value	$ 551,021	$ 393,244