Derivative Instruments and Hedging Activities - Fair Value of Derivative Instruments Reported in Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Millions	Jul. 03, 2015	Sep. 26, 2014
Derivatives Fair Value [Line Items]
Derivative assets	$ 1.0	$ 1.5
Foreign exchange forward contracts \| Derivatives Designated as Hedging Instruments \| Prepaid expenses and other current assets
Derivatives Fair Value [Line Items]
Derivative assets	0.5	1.5
Foreign exchange forward contracts \| Derivatives Not Designated as Hedging Instrument \| Prepaid expenses and other current assets
Derivatives Fair Value [Line Items]
Derivative assets	$ 0.5	$ 0.0

Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 55

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226000-175313

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant