Fair Value Measurements (Fair Value Inputs on a Nonrecurring Basis) (Details) - Operating lease right-of-use-asset and property, fixtures and equipment - Fair value, measurements, nonrecurring - Fair value, inputs, level 3	9 Months Ended
	Sep. 27, 2020
Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, weighted-average cost of capital	10.40%
Fair value inputs, long-term growth rate	1.50%
Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value inputs, weighted-average cost of capital	11.30%
Fair value inputs, long-term growth rate	2.00%