Organization and Summary of Significant Accounting Policies - Revenue, Defined Contrib. Plans, Advertising, Self-Insurance (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Contribution Plans
Expense incurred relating to defined contribution plans	$ 31.5	$ 21.1	$ 29.4
Advertising
Net advertising costs	119.2	81.1	112.6
Reimbursement of advertising expense	15.4	13.3	$ 19.2
Self Insurance
Aggregate reserves relating to retained risk	$ 33.5	29.7
Finance and insurance, net \| Retail Automotive and Retail Commercial Truck Dealership
Dealership Finance and Insurance Sales
Payment period	30 days
Aggregate reserves relating to chargeback activity	$ 33.7	$ 28.7

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The payment collection period as it relates to revenue.

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Represents the aggregate amount of reserves for chargeback of sales commission as of the balance sheet date.

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Self Insurance [Abstract]

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Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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-Publisher FASB
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Total amount received by an entity from a vendor under a cooperative advertising arrangement that has been offset against advertising expense.

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Amount of cost for defined contribution plan.

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This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties.

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