Stock-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Oct. 27, 2012	Oct. 29, 2011	Oct. 27, 2012	Oct. 29, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-Based Compensation Expense			$ 11,207	$ 9,376
Selling And Administrative Expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Restricted Stock Expense	4,565	4,052	8,192	8,131
Restricted Stock Units Expense	763	397	1,469	768
Stock Option Expense	614	238	1,321	477
Stock-Based Compensation Expense	$ 5,942	$ 4,687	$ 10,982	$ 9,376

The noncash expense that accounts for the value of stock or unit options distributed to employees as compensation.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration