Business Combinations - Consideration Paid and Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Summary of the aggregate consideration paid and the aggregate amounts of the assets acquired and liabilities assumed
Accounts receivable	$ 3.9	$ 52.0
Inventory	80.5	198.6
Other current assets	0.1	3.2
Property and equipment	16.4	98.1
Indefinite-lived intangibles	51.1	115.6
Other non-current assets	2.7	2.3
Current liabilities	(9.2)	(66.0)
Non-current liabilities	(4.7)	(75.5)
Total consideration	140.8	328.3
Seller financed/assumed debt		(2.6)
Seller assumed floorplan		(118.3)
Fair value of previously held interest		(28.0)
Fair value of non-controlling interest		(22.5)
Total cash used in acquisitions	$ 140.8	$ 156.9

Represents the amount of acquisition cost of a business combination allocated to indefinite-lived intangible assets.

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- Definition

Amount of Floorplan debt assumed at the acquisition date.

+ References

No definition available.

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- Definition

Fair value at acquisition-date of the assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interests issued by the acquirer, including but not limited to, instruments or interests issued or issuable in consideration for the business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=65885119&loc=d3e1392-128463

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
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-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- Definition

Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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- Definition

Amount due from customers or clients for goods or services, including trade receivables, that have been delivered or sold in the normal course of business, and amounts due from others, including related parties expected to be converted to cash, sold or exchanged within one year or the normal operating cycle, if longer, acquired at the acquisition date.

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- Definition

Amount of liabilities due within one year or within the normal operating cycle, if longer, assumed at the acquisition date.

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- Definition

The amount of inventory recognized as of the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73530397&loc=d3e4845-128472

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI http://asc.fasb.org/extlink&oid=73531372&loc=d3e2207-128464

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- Definition

Amount of liabilities assumed at the acquisition date.

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- Definition

Amount of liabilities due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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- Definition

Amount of other assets expected to be realized or consumed after one year or the normal operating cycle, if longer, acquired at the acquisition date.

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- Definition

The amount of property, plant, and equipment recognized as of the acquisition date.

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- Definition

Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

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- Definition

Portion of equity (net assets) in a variable interest entity (VIE) not attributable, directly or indirectly, to the parent entity. That is, this is the portion of equity in a VIE that is attributable to the noncontrolling interest (previously referred to as minority interest).

+ References

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

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-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3213-108585

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