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Business Acquisitions and Dispositions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2014 Franchise | Sep. 30, 2014 Franchise | Mar. 31, 2014 Dealerships
Business Acquisition [Line Items] |  |  |
Aggregate purchase price of franchise |  | $ 15.3 |
Number of dealerships held for sale |  |  | 0
Number of franchises disposed | 2 | 5 |
Cash generated from disposition | $ 14.9 | $ 30.1 |
Number of franchise held for sale | 1 | 1 |
Mid-line Import Franchise [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Number of franchise acquired | 1 |  |
Luxury Franchise [Member] |  |  |
Business Acquisition [Line Items] |  |  |
Number of franchise acquired |  | 1 |

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- Definition Held for sale dealerships number. + References No definition available. + Details
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- Definition Number of dealerships. + References No definition available. + Details
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- Definition Number of franchises disposed. + References No definition available. + Details
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- Definition Proceeds from dispositions of franchises. + References No definition available. + Details
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- Details
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 + Details
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- Definition The number of businesses acquired by the entity during the period. + References No definition available. + Details
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