Acquisitions and Dispositions Acquisitions and Dispositions (Details textuals) $ in Millions	6 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)
Acquisitions and Dispositions (Textual) [Abstract]
Business Combination, Consideration Transferred	$ 60.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	3.9
Business Combination, Contingent Consideration, Payable to Sellers	$ 1.8
Gain (Loss) on Disposition of Business		$ 0.7
U.S. [Member]
Acquisitions and Dispositions (Textual) [Abstract]
Number Of Dealerships Acquired		2
Number of Dealerships Disposed	2	1
Gain (Loss) on Disposition of Business	$ 0.7
Number of Franchises Disposed		1
U.K. [Member]
Acquisitions and Dispositions (Textual) [Abstract]
Number Of Dealerships Acquired	12
Number of Franchises Acquired	17
Brazil [Member]
Acquisitions and Dispositions (Textual) [Abstract]
Number Of Dealerships Acquired	1
Number of Franchises Acquired	2
Number Of Dealerships Opened	2
Number Of Franchises Awarded	2
Number of Dealerships Disposed	4
Gain (Loss) on Disposition of Business	$ (1.4)
Number of Franchises Disposed		2