Derivative Financial Instruments - Fair Value of Derivative Instruments Included in Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Jan. 25, 2020	Apr. 27, 2019
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	$ 152	$ 380
Interest rate contracts, liabilities, fair value	7,728	3,194
Other Noncurrent Assets | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, assets, fair value	152	380
Other Accrued Liabilities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	2,823	1,034
Other Noncurrent Liabilities | Interest rate contracts
Derivatives, Fair Value [Line Items]
Interest rate contracts, liabilities, fair value	$ 4,905	$ 2,160