Pension and Other Postretirement Benefits - Pension Benefits - Net Periodic Pension Cost (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2022	Sep. 26, 2021	Sep. 25, 2022	Sep. 26, 2021
Pension Benefits
Service cost	$ 2,882	$ 2,276	$ 8,645	$ 6,828
Interest cost	10,121	8,717	30,365	26,151
Expected return on plan assets	(13,807)	(12,678)	(41,422)	(38,033)
Amortization of actuarial loss	4,909	6,877	14,728	20,632
Amortization of prior service credit	(486)	(486)	(1,459)	(1,458)
Net periodic postretirement benefit cost	3,619	4,706	10,857	14,120
Qualified Plans
Pension Benefits
Service cost	2,882	2,276	8,645	6,828
Interest cost	8,837	7,630	26,512	22,888
Expected return on plan assets	(13,807)	(12,678)	(41,422)	(38,033)
Amortization of actuarial loss	3,266	5,056	9,799	15,169
Amortization of prior service credit	(486)	(486)	(1,459)	(1,458)
Net periodic postretirement benefit cost	692	1,798	2,075	5,394
Non- Qualified Plans
Pension Benefits
Service cost	0	0	0	0
Interest cost	1,284	1,087	3,853	3,263
Expected return on plan assets	0	0	0	0
Amortization of actuarial loss	1,643	1,821	4,929	5,463
Amortization of prior service credit	0	0	0	0
Net periodic postretirement benefit cost	$ 2,927	$ 2,908	$ 8,782	$ 8,726