Retirement Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands		3 Months Ended		4 Months Ended	6 Months Ended
		Apr. 11, 2021	Apr. 12, 2020	Jan. 19, 2020	Apr. 11, 2021	Apr. 12, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension settlements			$ 300	$ 38,600
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost		$ 3,398	3,669		$ 7,930	$ 8,745
Expected return on plan assets		(4,463)	(4,706)		(10,414)	(11,362)
Pension settlements		0	321		0	38,927
Actuarial loss (gain)	[1]	1,213	1,019		2,829	2,691
Amortization of unrecognized prior service cost	[1]	4	19		10	45
Net periodic benefit cost		152	322		355	39,046
Postretirement Healthcare Plans
Defined Benefit Plan Disclosure [Line Items]
Interest cost		130	187		303	435
Actuarial loss (gain)	[1]	(79)	3		(184)	9
Net periodic benefit cost		$ 51	$ 190		$ 119	$ 444

[1] Amounts were reclassified from accumulated other comprehensive loss into net earnings as a component of “Other pension and post-retirement expenses, net