Pension and Other Postretirement Benefits - Pension Benefits - Net Periodic Pension (Income)/Cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 26, 2022	Jun. 30, 2023	Jun. 26, 2022
Pension Benefits
Service cost	$ 1,417	$ 2,882	$ 2,835	$ 5,763
Interest cost	16,494	10,121	32,987	20,243
Expected return on plan assets	(19,122)	(13,807)	(38,245)	(27,615)
Amortization of actuarial loss	1,553	4,909	3,107	9,819
Amortization of prior service credit	(486)	(486)	(972)	(972)
Net periodic pension (income)/cost or postretirement benefit cost	(144)	3,619	(288)	7,238
Qualified Plans
Pension Benefits
Service cost	1,417	2,882	2,835	5,763
Interest cost	14,198	8,837	28,396	17,675
Expected return on plan assets	(19,122)	(13,807)	(38,245)	(27,615)
Amortization of actuarial loss	663	3,266	1,327	6,532
Amortization of prior service credit	(486)	(486)	(972)	(972)
Net periodic pension (income)/cost or postretirement benefit cost	(3,330)	692	(6,659)	1,383
Non- Qualified Plans
Pension Benefits
Service cost	0	0	0	0
Interest cost	2,296	1,284	4,591	2,568
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	890	1,643	1,780	3,287
Amortization of prior service credit	0	0	0	0
Net periodic pension (income)/cost or postretirement benefit cost	$ 3,186	$ 2,927	$ 6,371	$ 5,855