Employee Benefit Plans - Schedule of Defined Benefit Plans Disclosure (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 25, 2021	Sep. 26, 2020	Sep. 28, 2019
Pension Benefits [Member]
Reconciliation of benefit obligations:
Benefit obligation at beginning of year	$ 115,232	$ 115,471
Interest cost	2,263	2,726	$ 3,943
Actuarial (gain) loss	(4,461)	7,005
Lump sum benefits paid	(3,859)	(3,623)	(3,869)
Ordinary benefits paid	(6,060)	(6,347)
Benefit obligation at end of year	103,115	115,232	115,471
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	80,001	80,913
Actual gain return on plan assets	1,540	5,223
Employer contributions	6,270	3,835	5,350
Lump sum benefits paid	(3,859)	(3,623)
Ordinary benefits paid	(6,060)	(6,347)
Fair value of plan assets at end of year	77,892	80,001	80,913
Funded status:
Funded status at end of year	(25,223)	(35,231)
Amounts recognized in consolidated balance sheets consist of:
Net amount recognized at end of year	(25,223)	(35,231)
Less: current portion	0	0
Noncurrent benefit liability	(25,223)	(35,231)
Amounts not yet recognized in net periodic benefit cost and included in accumulated other comprehensive income (loss):
Actuarial net (loss) gain	(23,303)	(32,286)
Prior service credits	0	0
Net amount recognized in accumulated other comprehensive (loss) income	(23,303)	(32,286)
Retiree Health and Life Benefits [Member]
Reconciliation of benefit obligations:
Benefit obligation at beginning of year	5,999	6,929
Interest cost	77	151	275
Actuarial (gain) loss	(431)	(246)
Lump sum benefits paid	0	0
Ordinary benefits paid	(683)	(835)
Benefit obligation at end of year	4,962	5,999	6,929
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	0	0
Actual gain return on plan assets	0	0
Employer contributions	683	835
Lump sum benefits paid	0	0
Ordinary benefits paid	(683)	(835)
Fair value of plan assets at end of year	0	0	$ 0
Funded status:
Funded status at end of year	(4,962)	(5,999)
Amounts recognized in consolidated balance sheets consist of:
Net amount recognized at end of year	(4,962)	(5,999)
Less: current portion	710	843
Noncurrent benefit liability	(4,252)	(5,156)
Amounts not yet recognized in net periodic benefit cost and included in accumulated other comprehensive income (loss):
Actuarial net (loss) gain	4,465	4,757
Prior service credits	1,255	1,753
Net amount recognized in accumulated other comprehensive (loss) income	$ 5,720	$ 6,510