Amounts Reclassified Out of Accumulated Other Comprehensive Income - Reclassification out of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		3 Months Ended
		Dec. 30, 2017	Dec. 24, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		$ (28,812)	$ (45,832)
Other comprehensive income before reclassifications		0	(5)
Reclassifications to earnings		757	1,403
Other comprehensive income		757	1,398
Balance ending		(28,055)	(44,434)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		0	(205)
Other comprehensive income before reclassifications		0	(5)
Reclassifications to earnings	[1]	0	200
Other comprehensive income		0	195
Balance ending		0	(10)
Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		(37,311)	(51,391)
Other comprehensive income		921	1,300
Balance ending		(36,390)	(50,091)
Amortization of Net Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	921	1,300
Post-Retirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		8,499	5,764
Other comprehensive income		(164)	(97)
Balance ending		8,335	5,667
Amortization of Net (Gain) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	$ (164)	$ (97)

[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 13, “Pension Plans and Other Postretirement Benefits.”