DEBT - Schedule of Non-Recourse Notes Payable (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
Debt Instrument [Line Items]
Proceeds from issuance of non-recourse notes payable	$ 739.0	$ 1,036.4
Non-recourse | Asset Backed Funding Vehicles
Debt Instrument [Line Items]
Proceeds from issuance of non-recourse notes payable	739.0
Non-recourse notes payable | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	2,025.8
Initial Principal Amount	3,254.5
Non-recourse notes payable | LAD Auto Receivables Trust 2021-1 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	68.8
Initial Principal Amount	$ 344.4
Non-recourse notes payable | LAD Auto Receivables Trust 2021-1 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	1.30%
Non-recourse notes payable | LAD Auto Receivables Trust 2021-1 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	3.99%
Non-recourse notes payable | LAD Auto Receivables Trust 2022-1 Class A-C | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 112.9
Initial Principal Amount	$ 298.1
Non-recourse notes payable | LAD Auto Receivables Trust 2022-1 Class A-C | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	5.21%
Non-recourse notes payable | LAD Auto Receivables Trust 2022-1 Class A-C | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	6.85%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-1 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 241.0
Initial Principal Amount	$ 479.7
Non-recourse notes payable | LAD Auto Receivables Trust 2023-1 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	5.48%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-1 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	7.30%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-2 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 320.9
Initial Principal Amount	$ 556.7
Non-recourse notes payable | LAD Auto Receivables Trust 2023-2 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	5.42%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-2 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	6.30%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-3 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 281.8
Initial Principal Amount	$ 415.4
Non-recourse notes payable | LAD Auto Receivables Trust 2023-3 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	5.95%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-3 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	6.92%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-4 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 314.3
Initial Principal Amount	$ 421.2
Non-recourse notes payable | LAD Auto Receivables Trust 2023-4 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	6.10%
Non-recourse notes payable | LAD Auto Receivables Trust 2023-4 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	7.37%
Non-recourse notes payable | LAD Auto Receivables Trust 2024-1 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 276.5
Initial Principal Amount	$ 329.4
Non-recourse notes payable | LAD Auto Receivables Trust 2024-1 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	5.17%
Non-recourse notes payable | LAD Auto Receivables Trust 2024-1 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	6.15%
Non-recourse notes payable | LAD Auto Receivables Trust 2024-2 Class A-D | Non-recourse
Debt Instrument [Line Items]
Long-term debt, gross	$ 409.6
Initial Principal Amount	$ 409.6
Non-recourse notes payable | LAD Auto Receivables Trust 2024-2 Class A-D | Non-recourse | Minimum
Debt Instrument [Line Items]
Interest Rate Range	5.46%
Non-recourse notes payable | LAD Auto Receivables Trust 2024-2 Class A-D | Non-recourse | Maximum
Debt Instrument [Line Items]
Interest Rate Range	6.37%