Credit Facilities and Long-term Debt - Schedule of Non-Recourse Notes Payable (Details) - Non-recourse notes payable - Nonrecourse - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total long-term debt	$ 2,109.3	$ 1,705.6
Aggregate principal amount	3,869.4
LAD Auto Receivables Trust 2021-1 Class A-D
Debt Instrument [Line Items]
Total long-term debt	44.8
Aggregate principal amount	$ 344.4
LAD Auto Receivables Trust 2021-1 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	1.94%
LAD Auto Receivables Trust 2021-1 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	3.99%
LAD Auto Receivables Trust 2022-1 Class A-C
Debt Instrument [Line Items]
Total long-term debt	$ 80.9
Aggregate principal amount	$ 298.1
LAD Auto Receivables Trust 2022-1 Class A-C \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.21%
LAD Auto Receivables Trust 2022-1 Class A-C \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	6.85%
LAD Auto Receivables Trust 2023-1 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 178.3
Aggregate principal amount	$ 479.7
LAD Auto Receivables Trust 2023-1 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.48%
LAD Auto Receivables Trust 2023-1 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	7.30%
LAD Auto Receivables Trust 2023-2 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 245.2
Aggregate principal amount	$ 556.7
LAD Auto Receivables Trust 2023-2 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.42%
LAD Auto Receivables Trust 2023-2 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	6.30%
LAD Auto Receivables Trust 2023-3 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 220.7
Aggregate principal amount	$ 415.4
LAD Auto Receivables Trust 2023-3 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.95%
LAD Auto Receivables Trust 2023-3 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	6.92%
LAD Auto Receivables Trust 2023-4 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 247.5
Aggregate principal amount	$ 421.2
LAD Auto Receivables Trust 2023-4 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	6.10%
LAD Auto Receivables Trust 2023-4 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	7.37%
LAD Auto Receivables Trust 2024-1 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 219.9
Aggregate principal amount	$ 329.4
LAD Auto Receivables Trust 2024-1 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.17%
LAD Auto Receivables Trust 2024-1 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	6.15%
LAD Auto Receivables Trust 2024-2 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 320.0
Aggregate principal amount	$ 409.6
LAD Auto Receivables Trust 2024-2 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.46%
LAD Auto Receivables Trust 2024-2 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	6.37%
LAD Auto Receivables Trust 2024-3 Class A-D
Debt Instrument [Line Items]
Total long-term debt	$ 552.0
Aggregate principal amount	$ 614.9
LAD Auto Receivables Trust 2024-3 Class A-D \| Minimum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	4.52%
LAD Auto Receivables Trust 2024-3 Class A-D \| Maximum
Debt Instrument [Line Items]
Debt stated interest rate (as a percent)	5.18%