Debt (Non-Recourse Debt) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Less: current maturities	$ (10.9)	$ (8.8)
Non-recourse debt, net of current maturities	334.3	249.6
Restricted cash included in Other Current Assets	18.9	14.3
Auto loans receivable	566.5	451.2
Variable Interest Entity, Primary Beneficiary | Asset Pledged as Collateral
Debt Instrument [Line Items]
Restricted cash included in Other Current Assets	4.0	4.3
Auto loans receivable	43.1	50.8
Nonrecourse
Debt Instrument [Line Items]
Non Recourse Debt	346.3	259.9
Less: unamortized debt discounts and debt issuance costs	(1.1)	(1.5)
Less: current maturities	(10.9)	(8.8)
Non-recourse debt, net of current maturities	334.3	249.6
Warehouse Facilities | Nonrecourse
Debt Instrument [Line Items]
Non Recourse Debt	303.5	209.4
Warehouse Facilities Maximum Borrowing Capacity	450.0
Term securitization debt | Nonrecourse | Variable Interest Entity, Primary Beneficiary
Debt Instrument [Line Items]
Non Recourse Debt	$ 42.8	$ 50.5
Term securitization debt | Minimum | Nonrecourse | Variable Interest Entity, Primary Beneficiary
Debt Instrument [Line Items]
Percentage interest on debt instrument	1.79%
Term securitization debt | Maximum | Nonrecourse | Variable Interest Entity, Primary Beneficiary
Debt Instrument [Line Items]
Percentage interest on debt instrument	4.45%