Benefit Plans - Allocation of Plan Assets (Details)	Dec. 26, 2020	Dec. 28, 2019
Defined Benefit Plan Disclosure
Asset Allocation	100.00%	100.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure
Asset Allocation	7.00%	1.00%
Equity securities
Defined Benefit Plan Disclosure
Asset Allocation	9.00%	27.00%
Fixed income securities
Defined Benefit Plan Disclosure
Asset Allocation	31.00%	72.00%
Bulk annuity contract
Defined Benefit Plan Disclosure
Asset Allocation	53.00%	0.00%