Stock Incentive and Purchase Plans (Summary of Stock Options) (Details) (USD $)	12 Months Ended
Apr. 26, 2013	Apr. 27, 2012	Apr. 29, 2011
Stock Incentive and Purchase Plans [Abstract]
Weighted average grant date fair value of stock option awards during the fiscal year	$ 20.55	$ 12.31	$ 11.78
Aggregate intrinsic value of stock option exercises during the fiscal year	$ 11,475,610	$ 5,636,206	$ 9,632,100

The total accumulated difference between fair values of underlying shares on dates of exercise and exercise price on options which were exercised (or share units converted) into shares during the reporting period under the plan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph c(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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