Amounts Reclassified Out of Accumulated Other Comprehensive Income - Reclassification out of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 24, 2016	Dec. 26, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		$ (45,832)	$ (48,883)
Other comprehensive income before reclassifications		(5)	177
Reclassifications to earnings		1,403	1,292
Other comprehensive income		1,398	1,469
Balance ending		(44,434)	(47,414)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		(205)	(1,311)
Other comprehensive income before reclassifications		(5)	177
Reclassifications to earnings	[1]	200	333
Other comprehensive income		195	510
Balance ending		(10)	(801)
Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		(51,391)	(52,836)
Other comprehensive income		1,300	1,134
Balance ending		(50,091)	(51,702)
Amortization of Net Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	1,300	1,134
Post-Retirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		5,764	5,264
Other comprehensive income		(97)	(175)
Balance ending		5,667	5,089
Amortization of Prior Service Credits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	0	(100)
Amortization of Net (Gain) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	$ (97)	$ (75)

[1] Reclassification of realized losses on cash flow hedges are recognized in interest expense.

[2] These amounts are included in the computation of net periodic benefit cost. See Note 12, “Pension Plans and Other Postretirement Benefits.”