Benefit Plans - Benefit Plan Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2021	Jun. 27, 2020	Jun. 26, 2021	Jun. 27, 2020
Retirement Benefits [Abstract]
Service cost	$ 700	$ 592	$ 1,402	$ 1,210
Interest cost	443	486	883	1,144
Expected return on plan assets	(371)	(402)	(738)	(1,129)
Amortization of prior service and net actuarial loss	334	264	665	409
Net periodic benefit cost	$ 1,106	$ 940	$ 2,212	$ 1,634