Other Postretirement Benefits - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 26, 2021	Dec. 27, 2020	Oct. 31, 2020
Other Postretirement Benefits
Benefit obligation				$ 236,300
Other Postretirement Benefit Plans
Other Postretirement Benefits
Additional postretirement costs	$ 19,000	$ 17,000	$ 16,000
Benefit obligation	30,696	40,607	$ 43,308
Actuarial gain (loss)	6,801	(2,254)
Plan assets, benefits paid	6,158	7,892
Benefits paid	6,158	7,892
Employer contributions	3,887	5,573
Postemployment benefits liability	$ 7,900	$ 8,500