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Shareholders' Equity (Shares Issued And Shares Surrendered To Satisfy Tax Withholdings In Connection With Restricted Stock And Restricted Stock Units) (Details) - shares | 3 Months Ended | 9 Months Ended
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Sep. 30, 2020 | Sep. 30, 2019 | Sep. 30, 2020 | Sep. 30, 2019
Restricted Stock And Restricted Stock Units [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares surrendered to AutoNation to satisfy tax withholding obligations (in shares) | 4,288 | 899 | 190,888 | 85,331
Restricted Stock Units (RSUs) [Member] |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |
Shares issued (in shares) | 10,896 | 2,045 | 512,917 | 306,346

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement. + References No definition available. + Details
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- Definition Number, before forfeiture, of shares issued under share-based payment arrangement. Excludes employee stock ownership plan (ESOP). + References No definition available. + Details
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