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Acquisitions and Dispositions Acquisitions and Dispositions (Details textuals) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2015 USD ($) | Dec. 31, 2014 USD ($)
Acquisitions and Dispositions (Textual) [Abstract] |  |
Business Combination, Consideration Transferred |  | $ 336,600,000
Gain (Loss) on Disposition of Business | $ 700,000.0 |
U.S. [Member] |  |
Acquisitions and Dispositions (Textual) [Abstract] |  |
Number of Franchises Disposed | 1 |
Number Of Dealerships Acquired | 3 | 7
Number of Franchises Awarded |  | 2
Business Acquisition Purchase Price Allocation Goodwill | $ 103,800,000 |
Number of Dealerships Disposed | 1 |
U.K. [Member] |  |
Acquisitions and Dispositions (Textual) [Abstract] |  |
Number Of Dealerships Acquired |  | 3
Business Acquisition Purchase Price Allocation Goodwill | $ 18,500,000 |
Brazil [Member] |  |
Acquisitions and Dispositions (Textual) [Abstract] |  |
Number of Franchises Disposed | 2 |
Number Of Dealerships Acquired |  | 1
Number of Franchises Awarded |  | 1
Business Acquisition Purchase Price Allocation Goodwill | $ 0 |

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