Retirement Benefits Retirement Benefits (Level 3 Asset Rollforward) (Details) - Fair Value, Nonrecurring [Member] - Pension Benefits - Level 3 - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 25, 2020
Defined Benefit Plan, Plan Assets, Level 3 Reconciliation [Line Items]
Balance, beginning of year	$ 31,877	$ 27,675
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	2,430	2,255
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Sales	2,556	1,425
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)	(825)	3,372
Balance, end of year	$ 30,926	$ 31,877