Derivative Financial Instruments - Fair Value of Derivative Instruments Included in Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Oct. 26, 2019	Apr. 27, 2019
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	$ 196	$ 380
Interest rate contracts, liabilities, fair value	8,050	3,194
Other Noncurrent Assets | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	196	380
Other Accrued Liabilities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	2,943	1,034
Other Noncurrent Liabilities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	$ 5,107	$ 2,160