Pension and Postretirement Benefits - Summary of Net Periodic Benefit Cost Recognized (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Jun. 30, 2019
COMPONENTS OF NET PERIODIC BENEFIT COST:
Plan Settlements			$ 31,900
SERP Benefits
COMPONENTS OF NET PERIODIC BENEFIT COST:
Service Cost	$ 16	$ 19
Interest Cost	10	15
Amortization of Unrecognized Net Loss	3	4
Net Periodic Benefit Cost	29	38
Postretirement Benefits
COMPONENTS OF NET PERIODIC BENEFIT COST:
Service Cost	3	3
Interest Cost	4	6
Amortization of Prior Service Credit	(2)	(7)
Amortization of Unrecognized Net Loss	89	99
Net Periodic Benefit Cost	$ 94	$ 101