Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 940
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68072869&loc=d3e41242-110953

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
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-Subparagraph (SX 210.5-03(10))
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

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- Definition

Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
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Segment Information (Details) $ in Millions	3 Months Ended		12 Months Ended
Segment Information (Details) $ in Millions	Mar. 31, 2017 USD ($) item	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information
Number of reportable Segments \| item	4
Number of operating segments \| item	6
Revenues and segment income by reportable segment
Revenues	$ 5,081.1	$ 4,824.6
Segment income	124.7	119.6
Intersegment Elimination
Revenues and segment income by reportable segment
Revenues		(1.0)
Retail Automotive Dealership
Revenues and segment income by reportable segment
Revenues	4,756.4	4,512.9	$ 18,700.0
Retail Automotive Dealership \| Operating segments
Revenues and segment income by reportable segment
Revenues	4,756.4	4,512.9
Segment income	104.8	110.4
Retail Commercial Truck Dealership
Revenues and segment income by reportable segment
Revenues	211.7	206.7
Retail Commercial Truck Dealership \| Operating segments
Revenues and segment income by reportable segment
Revenues	211.7	206.7
Segment income	6.5	5.8
Other \| Operating segments
Revenues and segment income by reportable segment
Revenues	113.0	106.0
Segment income	0.9	(0.7)
Non-Automotive Investments \| Operating segments
Revenues and segment income by reportable segment
Segment income	$ 12.5	$ 4.1