Employee Benefit Plans - Schedule of Defined Benefit Plans Disclosure (Details) - USD ($)	12 Months Ended
	Sep. 24, 2016	Sep. 26, 2015	Sep. 27, 2014
Reconciliation of benefit obligations:
Lump sum benefits paid	$ (5,816,000)	$ (5,777,000)
Pension Benefits [Member]
Reconciliation of benefit obligations:
Benefit obligation at beginning of year	146,907,000	149,836,000
Interest cost	5,041,000	5,128,000	$ 5,774,000
Actuarial loss (gain)	11,547,000	5,239,000
Lump sum benefits paid	(5,816,000)	(5,777,000)
Ordinary benefits paid	(7,316,000)	(7,519,000)
Benefit obligation at end of year	150,363,000	146,907,000	149,836,000
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	104,303,000	117,771,000
Actual return on plan assets	9,191,000	(172,000)
Employer contributions	715,000	0	0
Lump sum benefits paid	(5,816,000)	(5,777,000)
Ordinary benefits paid	(7,316,000)	(7,519,000)
Fair value of plan assets at end of year	101,077,000	104,303,000	117,771,000
Funded status:
Funded status at end of year	(49,286,000)	(42,604,000)
Amounts recognized in consolidated balance sheets consist of:
Net amount recognized at end of year	(49,286,000)	(42,604,000)
Less: current portion	0	0
Noncurrent benefit liability	(49,286,000)	(42,604,000)
Amounts not yet recognized in net periodic benefit cost and included in accumulated other comprehensive income (loss):
Actuarial net (loss) gain	(51,391,000)	(52,836,000)
Prior service credits	0	0
Net amount recognized in accumulated other comprehensive (loss) income	(51,391,000)	(52,836,000)
Retiree Health and Life Benefits [Member]
Reconciliation of benefit obligations:
Benefit obligation at beginning of year	15,294,000	16,954,000
Interest cost	520,000	575,000	645,000
Actuarial loss (gain)	(1,198,000)	(1,281,000)
Lump sum benefits paid	0	0
Ordinary benefits paid	(838,000)	(954,000)
Benefit obligation at end of year	13,778,000	15,294,000	16,954,000
Reconciliation of fair value of plan assets:
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	838,000	954,000
Lump sum benefits paid	0	0
Ordinary benefits paid	(838,000)	(954,000)
Fair value of plan assets at end of year	0	0	$ 0
Funded status:
Funded status at end of year	(13,778,000)	(15,294,000)
Amounts recognized in consolidated balance sheets consist of:
Net amount recognized at end of year	(13,778,000)	(15,294,000)
Less: current portion	922,000	1,025,000
Noncurrent benefit liability	(12,856,000)	(14,269,000)
Amounts not yet recognized in net periodic benefit cost and included in accumulated other comprehensive income (loss):
Actuarial net (loss) gain	5,764,000	4,865,000
Prior service credits	0	399,000
Net amount recognized in accumulated other comprehensive (loss) income	$ 5,764,000	$ 5,264,000