Pension and Other Postretirement Benefits - Pension Benefits - Net Periodic Pension (Income)/Cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 25, 2022	Sep. 30, 2023	Sep. 25, 2022
Pension Benefits
Service cost	$ 1,417	$ 2,882	$ 4,252	$ 8,645
Interest cost	16,494	10,121	49,482	30,365
Expected return on plan assets	(19,122)	(13,807)	(57,367)	(41,422)
Amortization of actuarial loss	1,553	4,909	4,660	14,728
Amortization of prior service credit	(486)	(486)	(1,459)	(1,459)
Net periodic pension (income)/cost or postretirement benefit cost	(144)	3,619	(432)	10,857
Qualified Plans
Pension Benefits
Service cost	1,417	2,882	4,252	8,645
Interest cost	14,198	8,837	42,595	26,512
Expected return on plan assets	(19,122)	(13,807)	(57,367)	(41,422)
Amortization of actuarial loss	663	3,266	1,991	9,799
Amortization of prior service credit	(486)	(486)	(1,459)	(1,459)
Net periodic pension (income)/cost or postretirement benefit cost	(3,330)	692	(9,988)	2,075
Non- Qualified Plans
Pension Benefits
Service cost	0	0	0	0
Interest cost	2,296	1,284	6,887	3,853
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	890	1,643	2,669	4,929
Amortization of prior service credit	0	0	0	0
Net periodic pension (income)/cost or postretirement benefit cost	$ 3,186	$ 2,927	$ 9,556	$ 8,782