Stockholders' Equity - Summary of Valuation Assumptions (Detail) - $ / shares	12 Months Ended
Apr. 28, 2017	Apr. 29, 2016	Apr. 24, 2015
Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	0 years	0 years	4 years 9 months 18 days
Risk-free interest rate			1.60%
Expected volatility			29.00%
Expected dividend yield			1.80%
Weighted-average fair value per share granted			$ 8.24
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.00%	0.60%	0.60%
Expected dividend yield	3.10%	2.30%	1.80%
RSUs granted, Weighted-Average Grant Date Fair Value	$ 24.99	$ 29.26	$ 35.80
Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term in years	1 year 2 months 12 days	1 year 2 months 12 days	1 year 3 months 18 days
Risk-free interest rate	0.80%	0.50%	0.20%
Expected volatility	30.00%	27.00%	27.00%
Expected dividend yield	3.10%	2.30%	1.80%
RSUs granted, Weighted-Average Grant Date Fair Value	$ 7.85	$ 8.18	$ 9.81

The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809

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