Shareholders' Equity (Shares Issued And Shares Surrendered To Satisfy Tax Withholdings In Connection With Restricted Stock And Restricted Stock Units) (Details) - Restricted Stock And Restricted Stock Units [Member] - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	122,661	20,000	143,424
Shares surrendered to AutoNation to satisfy tax withholding obligations (in shares)	56,027	26,514	38,906