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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
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)	1,616	2,260	224,133	186,600
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued (in shares)	7,341	7,340	639,192	502,021