Pension Plans and Other Postretirement Benefits - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 25, 2022	Jun. 26, 2021	Mar. 27, 2021	Jun. 25, 2022	Jun. 26, 2021
Defined Benefit Plan Disclosure [Line Items]
Pension settlement charge				$ (634)	$ (712)
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 559	$ 534		1,678	1,602
Expected return on plan assets	(353)	(319)		1,061	(957)
Amortization of net loss (gain)	598	899		(1,797)	2,695
Pension settlement charge	634	142	$ 570	634	712
Net periodic benefit cost	1,438	1,256		3,048	4,052
Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	20	20		60	58
Amortization of prior service credits	(124)	(124)		(373)	(373)
Amortization of net loss (gain)	(181)	(182)		543	(543)
Net periodic benefit cost	$ (285)	$ (286)		$ (856)	$ (858)