Number of suspense shares held by the Employee Stock Option Plan at balance sheet date. Suspense shares are shares that have not been released, committed to be released or allocated to individual participant accounts.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 40

-Section 50

-Paragraph 1

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 93-6

-Paragraph 53

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

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

Employee Stock Ownership Plan (ESOP) - Additional Information (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 26, 2013	Jan. 28, 2012	Jan. 26, 2013	Jan. 28, 2012	Apr. 27, 1991 H
Shareholders Equity [Line Items]
Hours of service completed in order to be allocated shares of stock acquired by plan					1,000
Number of unallocated shares held by ESOP	3,589,345		3,589,345
ESOP compensation	$ 5,700	$ 6,100	$ 17,100	$ 18,250
1990 Note
Shareholders Equity [Line Items]
ESOP company loan					22,000