Derivative Financial Instruments - Effect of Interest Rate Contracts on Condensed Consolidated Statements of Income and Other Comprehensive Income (OCI) (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Jan. 30, 2016	Jan. 24, 2015	Jan. 30, 2016	Jan. 24, 2015
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Effect of interest rate contracts	$ 442	$ (8,143)	$ 1,496	$ (14,319)

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=56946850&loc=SL5624171-113959

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