Fair Value (Details) (Measured at fair value on a recurring basis, Level 3, Interest Rate Hedges, USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Oct. 27, 2013	Oct. 28, 2012	Oct. 27, 2013	Oct. 28, 2012
Measured at fair value on a recurring basis \| Level 3 \| Interest Rate Hedges
Changes in Level 3 liabilities
Balance at the beginning of the period	$ (326)	$ (2,121)	$ (794)	$ (2,493)
Realized gain/(losses)	326	413	794	785
Balance at the end of the period		$ (1,708)		$ (1,708)

Amount of gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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