Auto Loans Receivable - Financing Receivable, Past Due (Details) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Financing Receivable, Past Due [Line Items]
Total auto loans receivable	$ 2,444.7	$ 2,209.9
Total Past Due
Financing Receivable, Past Due [Line Items]
Total auto loans receivable	51.6	59.2
31-60 Days
Financing Receivable, Past Due [Line Items]
Total auto loans receivable	40.5	44.2
61-90 Days
Financing Receivable, Past Due [Line Items]
Total auto loans receivable	7.7	10.8
Greater than 90 Days
Financing Receivable, Past Due [Line Items]
Total auto loans receivable	3.4	4.2
Current
Financing Receivable, Past Due [Line Items]
Total auto loans receivable	$ 2,393.1	$ 2,150.7