Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Fair Value Measurements - Narrative (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended
	Mar. 27, 2020	Jun. 26, 2020	Mar. 27, 2020	Jun. 28, 2019	Jun. 26, 2020	Jun. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of goodwill		$ 0.0		$ 0.0	$ 85.3	$ 0.0
Telematics Reporting Unit
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment of goodwill	$ 85.3		$ 85.3