FLOOR PLAN NOTES PAYABLE—NON-TRADE - Narrative (Details)		12 Months Ended
	Oct. 20, 2023	Dec. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 29, 2022	May 27, 2022 USD ($)	Oct. 29, 2021 USD ($)	Oct. 16, 2014 USD ($)
Debt Instrument [Line Items]
Amount available under revolving loan credit facility transferred to new vehicle floor plan facility			$ 389,000,000				$ 389,000,000
Floor plan, notes payable, offset account, additional amount		$ 164,000,000
Accounts payable and accrued liabilities
Debt Instrument [Line Items]
Floor plan, notes payable, offset account, additional amount		$ 63,200,000
Senior Notes
Debt Instrument [Line Items]
Face amount					$ 250,000,000
2023 Senior Credit Facility
Debt Instrument [Line Items]
Debt instrument, variable rate, minimum	0.0100
2023 Senior Credit Facility | Minimum | Base Rate Component, Federal Funds
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
2023 Senior Credit Facility | Minimum | Base Rate Component, SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
2023 Senior Credit Facility | Minimum | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
2023 Senior Credit Facility | Minimum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.15%
2023 Senior Credit Facility | Maximum | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	2.00%
2023 Senior Credit Facility | Maximum | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
New Vehicle Floor Plan Facility | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	1.10%
New Vehicle Floor Plan Facility | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.10%
Used Vehicle Floor Plan Facility | SOFR
Debt Instrument [Line Items]
Basis spread on variable rate	1.40%
Used Vehicle Floor Plan Facility | Base Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.40%
Revolving Credit Facility1 | Minimum | Line of Credit
Debt Instrument [Line Items]
Commitment fee percentage		0.15%
Revolving Credit Facility1 | Maximum | Line of Credit
Debt Instrument [Line Items]
Commitment fee percentage		0.40%
New Vehicle and Used Vehicle Floor Plan | Line of Credit
Debt Disclosure [Abstract]
Unused capacity, commitment fee percentage		0.15%
Debt Instrument [Line Items]
Unused capacity, commitment fee percentage		0.15%
2019 Bank of America Revolving Credit Facility | Senior Notes
Debt Instrument [Line Items]
Debt instrument, covenant terms, debt offset amount, decrease in limit		$ 50,000,000
2019 Bank of America Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Revolving borrowing base						0.25
Aggregate commitments						0.20
2019 Bank of America Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Revolving borrowing base		0.40
Aggregate commitments		0.40
Loaner Vehicle Notes Payable - Bank of America
Debt Instrument [Line Items]
Notes Payable		$ 127,200,000		$ 10,800,000
Loaner Vehicle Notes Payable - OEMs
Debt Instrument [Line Items]
Notes Payable		$ 111,900,000		$ 83,700,000
Revolving Credit Facility | 2019 Senior Credit Facility | Bank of America
Debt Instrument [Line Items]
Aggregate commitments								$ 500,000,000
New Vehicle Revolving Floor Plan Facility | 2019 Senior Credit Facility | Bank of America
Debt Instrument [Line Items]
Aggregate commitments								1,930,000,000
Used Vehicle Revolving Floor Plan Facility
Debt Instrument [Line Items]
Commitment fee percentage		0.15%
Used Vehicle Revolving Floor Plan Facility | 2019 Senior Credit Facility | Bank of America
Debt Instrument [Line Items]
Aggregate commitments								$ 375,000,000
Senior Credit Facility | 2019 Senior Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 750,000,000
Standby Letters of Credit | Bank of America
Debt Instrument [Line Items]
Face amount		$ 50,000,000							$ 50,000,000