Postretirement and Postemployment Benefits - Benefit Obligations and Plan Assets (Details) - Other Postretirement Benefits Plan - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2023	Sep. 25, 2022
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of year	$ 12,287	$ 18,538
Service cost	68	108
Interest cost	598	340
Actuarial (gain) loss	(1,049)	(4,729)
Benefits paid, net of premiums received	(652)	(1,958)
Medicare Part D subsidies	0	(12)
Benefit obligation, end of year	11,252	12,287
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of year:	23,903	26,802
Actual return on plan assets	2,393	(2,453)
Employer contributions	165	1,525
Benefits paid, net of premiums and Medicare Part D subsidies received	(660)	(2,105)
Plan participant contributions	8	134
Fair value of plan assets, end of year	25,809	23,903
Funded status	$ 14,557	$ 11,616