Amounts Reclassified Out of Accumulated Other Comprehensive Income - Reclassification out of accumulated other comprehensive (loss) income (Details) - USD ($) $ in Thousands		12 Months Ended
		Sep. 26, 2015	Sep. 27, 2014	Sep. 28, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		$ (45,905)	$ (47,353)	$ (61,107)
Other comprehensive income before reclassifications		(10,202)	(3,779)	6,494
Recognition in earnings of net actuarial loss for pension settlement		2,000	0	0
Reclassifications to earnings		5,224	5,227	7,260
Other comprehensive (loss) income		(2,978)	1,448	13,754
Balance ending		(48,883)	(45,905)	(47,353)
Cash Flow Hedges [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		(1,540)	(2,428)	(5,477)
Other comprehensive income before reclassifications		(1,159)	(518)	584
Reclassifications to earnings	[1]	1,388	1,406	2,465
Other comprehensive (loss) income		229	888	3,049
Balance ending		(1,311)	(1,540)	(2,428)
Pension Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		(49,034)	(49,987)	(59,398)
Funded status benefit plan obligation		(10,324)	(3,539)	4,126
Recognition in earnings of net actuarial loss for pension settlement	[2]	2,000
Other comprehensive (loss) income		(3,802)	953	9,411
Balance ending		(52,836)	(49,034)	(49,987)
Amortization of Net Loss [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	4,522	4,492	5,285
Post-Retirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning		4,669	5,062	3,768
Funded status benefit plan obligation		1,281	278	1,784
Other comprehensive (loss) income		595	(393)	1,294
Balance ending		5,264	4,669	5,062
Amortization of Prior Service Credits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	(490)	(490)	$ (490)
Amortization of Net Gain [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassifications to earnings	[2]	$ (196)	$ (181)

[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 9, “Employee Benefit Plans”.