Description of Business and Basis of Presentation - Asset Impairment (Details) $ in Millions	3 Months Ended	9 Months Ended
Sep. 26, 2020 USD ($)	Sep. 26, 2020 USD ($)
Impaired Long-Lived Assets Held and Used [Line Items]
Asset impairment charges for certain stores and other assets	$ 7.2	$ 20.9
Estimated fair value of impaired assets	$ 28.1	28.1
Write-off of certain obsolete software assets		$ 1.1
Maximum
Impaired Long-Lived Assets Held and Used [Line Items]
Discount rate used in impairment analysis (percent)		8.00%
Minimum
Impaired Long-Lived Assets Held and Used [Line Items]
Discount rate used in impairment analysis (percent)		6.30%

The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 45
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration