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Intangibles - Narrative (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($) dealership	Sep. 30, 2019 USD ($)
Finite-Lived Intangible Assets [Line Items]
Additional indefinite-lived intangibles assets	$ 3.1
Additional goodwill acquired		$ 20.6
U.K.
Finite-Lived Intangible Assets [Line Items]
Number of dealerships below carrying values | dealership	7
Franchise asset impairment charges	$ 5.6
Additional goodwill acquired	$ 1.3	1.3
U.S.
Finite-Lived Intangible Assets [Line Items]
Number of dealerships below carrying values | dealership	1
Franchise asset impairment charges	$ 3.0
Additional goodwill acquired	$ 19.3	$ 19.3

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Number Of Dealerships Impaired

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
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-Section 50
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The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of an intangible asset (excluding goodwill) to fair value.

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