Income Taxes (Details 3) (Federal, USD $) In Thousands, unless otherwise specified	Apr. 26, 2015
Federal
Tax credit carryforwards
General business and AMT credit carryforwards	$ 24,860

Amount of deferred tax asset, before valuation allowance, attributable to deductible other tax carryforwards.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32537-109319

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 30

-Paragraph 5

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6907311&loc=d3e30536-109315

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