Postretirement and Postemployment Benefits - Benefit Obligations and Plan Assets (Details) - Other Postretirement Benefits Plan - USD ($) $ in Thousands	12 Months Ended
	Sep. 25, 2022	Sep. 26, 2021
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 18,538	$ 47,637
Service cost	108	207
Interest cost	340	429
Liability (gain)/loss due to curtailment	0	(23,830)
Actuarial loss (gain)	(4,729)	(4,285)
Benefits paid, net of premiums received	(1,958)	(1,678)
Medicare Part D subsidies	(12)	58
Benefit obligation, end of year	12,287	18,538
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year:	26,802	25,706
Actual return on plan assets	(2,453)	1,534
Employer contributions	1,525	1,293
Benefits paid, net of premiums and Medicare Part D subsidies received	(2,105)	(1,795)
Plan participant contributions	134	64
Fair value of plan assets, end of year	23,903	26,802
Funded status	$ 11,616	$ 8,264