Derivative Financial Instruments - Fair Value of Derivative Instruments Included in Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Jul. 27, 2019	Apr. 27, 2019
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	$ 149	$ 380
Interest rate contracts, liabilities, fair value	6,625	3,194
Other Noncurrent Assets | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	149	380
Other Accrued Liabilities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	2,486	1,034
Other Noncurrent Liabilities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	$ 4,139	$ 2,160