Retirement Benefits (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 24, 2021	Sep. 30, 2022	Sep. 24, 2021
Pension
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,053	$ 1,674	$ 6,187	$ 7,119
Interest cost	2,745	2,519	8,249	8,476
Expected return on assets	(5,237)	(5,412)	(14,816)	(15,673)
Amortization and other	1,200	2,148	3,695	7,254
Net periodic benefit cost	761	929	3,315	7,176
Postretirement Medical
Defined Benefit Plan Disclosure [Line Items]
Service cost	129	153	387	503
Interest cost	209	124	629	624
Amortization	86	252	259	752
Net periodic benefit cost	$ 424	$ 529	$ 1,275	$ 1,879