Acquisitions - Goodwill, Revenue and Pre-Tax (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Assets Or Stock Of Multiple Dealership Locations Acquired
Acquisitions
Goodwill for tax purposes	$ 30.8	$ 158.8
Revenue	91.1	300.8
Pre-tax income (loss)	4.2	14.2
Outdoor Lifestyle Retail Businesses
Acquisitions
Goodwill for tax purposes	3.6	36.5
Revenue	14.7	64.5
Pre-tax income (loss)		$ 28.8
Outdoor Lifestyle Retail Businesses \| Maximum
Acquisitions
Pre-tax income (loss)	$ 0.1

No definition available.

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- Definition

The amount of goodwill arising from a business combination that is expected to be deductible for tax purposes.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

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- Definition

This element represents the amount of earnings or loss of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

This element represents the amount of revenue of the acquiree since the acquisition date included in the consolidated income statement for the reporting period.

+ References

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