Derivative Financial Instruments - Effect of Derivative Instruments in Cash Flow Hedging Relationships on Condensed Consolidated Statements of Income and Other Comprehensive Income (OCI) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated other comprehensive loss expected to be reclassified into earnings			$ (2,900)
Interest rate contract
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated other comprehensive loss expected to be reclassified into earnings	$ (725)	$ (702)	(2,183)	$ (2,107)
Interest rate contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income on derivative				$ 0
Interest rate contract | Other income, net | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income on derivative	$ (284)	$ 0	$ (284)