Fair Value of Interest Rate Contracts on Consolidated Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Oct. 26, 2013	Apr. 27, 2013	Oct. 27, 2012
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	$ 810	$ 486
Interest rate contracts, liabilities, fair value	820	509
Other noncurrent assets
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	810	486	202
Other noncurrent liabilities
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	$ 820	$ 509	$ 247