Employee Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 24, 2022	Sep. 25, 2021	Sep. 26, 2020
Components of net periodic benefit costs included in operating expenses [Abstract]
Settlement charge	$ 840	$ 958	$ 1,051
Pension Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Interest cost	2,459	2,263	2,726
Expected return on plan assets	(1,392)	(1,266)	1,270
Amortization of prior service credit	0	0	0
Settlement charge	840	958	1,051
Recognized net actuarial loss (gain)	2,467	(3,289)	3,448
Net periodic benefit costs	4,374	5,244	5,955
Retiree Health and Life Benefits [Member]
Components of net periodic benefit costs included in operating expenses [Abstract]
Interest cost	81	77	151
Expected return on plan assets	0	0	0
Amortization of prior service credit	(498)	(498)	(498)
Settlement charge	0	0	0
Recognized net actuarial loss (gain)	(725)	(723)	(786)
Net periodic benefit costs	$ (1,142)	$ (1,144)	$ (1,133)