Employee Benefit Plans - Components Of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 27, 2022
Pension and SERPA Benefits:
Defined Benefit Plan Disclosure
Service cost	$ 1,294	$ 4,763
Interest cost	20,476	15,472
Expected return on plan assets	(36,519)	(31,476)
Amortization of unrecognized: Prior service cost (credit)	188	(328)
Amortization of unrecognized: Net (gain) loss	(181)	7,978
Settlement gain	(222)	(256)
Net periodic benefit income	(14,964)	(3,847)
Postretirement Healthcare Benefits:
Defined Benefit Plan Disclosure
Service cost	797	1,161
Interest cost	2,772	1,904
Expected return on plan assets	(4,281)	(3,809)
Amortization of unrecognized: Prior service cost (credit)	(166)	(581)
Amortization of unrecognized: Net (gain) loss	(1,097)	122
Net periodic benefit income	$ (1,975)	$ (1,203)