Derivatives and Hedging Activities - Schedule of Derivative Instruments Not Designated as Cash Flow Hedges (Detail) (Foreign Exchange Forward Contracts, USD $) In Millions, unless otherwise specified	3 Months Ended
Jul. 25, 2014	Jul. 26, 2013
Foreign Exchange Forward Contracts
Derivative Instruments, Gain (Loss) [Line Items]
Foreign currency exchange forward contracts	$ (0.8)	$ 0.2

Amount of realized and unrealized gain (loss) of derivative instruments not designated or qualifying as hedging instruments.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4C

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

Name:	us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration