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	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	0	0	20,000	152,683
Shares surrendered to AutoNation to satisfy tax withholding obligations (in shares)	141	4,788	26,061	37,673