Derivative Instruments - Effect of Derivative Instruments Recorded in Other Income (Expense) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 29, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Total derivative instruments	$ 0	$ (958)	$ 111
Commodity Contracts [Member] | Derivatives Not Designated as Hedging Instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total derivative instruments	$ 0	$ (958)	$ 111