Inventory And Vehicle Floorplan Payable (Narrative) (Details) (USD $)	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Inventory And Vehicle Floorplan Payable [Abstract]
Vehicle floorplan facilities, average LIBOR-based interest rates	2.40%	2.60%
Used floorplan facilities, maximum borrowing capacity	$ 245,000,000
Used floorplan facilities, amount outstanding	86,600,000
Used vehicle floorplan facilities, remaining borrowing capacity	158,400,000
Used vehicle floorplan facilities, current borrowing capacity	99,500,000
Vehicle floorplan facilities, maximum borrowing capacity	2,800,000,000
Vehicle floorplan facilities, amount outstanding	$ 1,511,300,000		$ 1,866,400,000