Commitments And Contingencies (Details)	3 Months Ended	9 Months Ended
	Sep. 27, 2020 USD ($)	Sep. 27, 2020 USD ($)
Guarantor Obligations [Line Items]
Maximum potential future undiscounted rental payments	$ 8,200,000	$ 8,200,000
Guarantor Obligations, Payments Made	0
Guarantor Obligations, Expected Future Payments		0
Guarantor Obligations, Current Carrying Value	$ 8,200,000	$ 8,200,000
Property Lease Guarantee [Member]
Guarantor Obligations [Line Items]
Property leases	27	27
Property leases, still in operation	6	6