Shareholders' Equity - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended			1 Months Ended
Jan. 25, 2014	Apr. 27, 2013	Jan. 26, 2013	May 15, 2007 Maximum	Jan. 25, 2014 Stock Repurchase Program	Jan. 26, 2013 Stock Repurchase Program
Class of Stock [Line Items]
Number of shares authorized to be repurchase				$ 400,000
Remaining authorized repurchase amount	$ 2,471
Treasury stock, shares	34,295,000	34,078,000	33,810,000		0	0

Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.28,29)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

Name:	us-gaap_TreasuryStockShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant