Benefit Plans - Benefit Plan Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 25, 2021	Sep. 26, 2020
Retirement Benefits [Abstract]
Service cost	$ 684	$ 615	$ 2,086	$ 1,825
Interest cost	434	511	1,317	1,655
Expected return on plan assets	(361)	(422)	(1,099)	(1,551)
Amortization of prior service and net actuarial loss	327	279	992	688
Net periodic benefit cost	$ 1,084	$ 983	$ 3,296	$ 2,617