Summary of Changes in Contract Liabilities Related to Gift Card Program (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jan. 26, 2019	Jan. 27, 2018	Jan. 26, 2019	Jan. 27, 2018
Gift Cards [Line Items]
Gift card liabilities balance as of April 28, 2018			$ 323,465
Gift card breakage	$ (28,258)	$ (27,496)	(36,304)	$ (37,224)
Gift card redemptions			(189,527)
Gift card issuances			231,809
Gift card liabilities balance as of January 26, 2019	239,296	$ 358,609	239,296	$ 358,609
Calculated under Revenue Guidance in Effect before Topic 606 | ASU 2014-09
Gift Cards [Line Items]
Gift card liabilities balance as of April 28, 2018			323,465
Gift card liabilities balance as of January 26, 2019	319,739		319,739
Difference between Revenue Guidance in Effect before and after Topic 606 | ASU 2014-09
Gift Cards [Line Items]
Gift card liabilities balance as of April 28, 2018			(90,147)
Gift card liabilities balance as of January 26, 2019	$ (80,443)		$ (80,443)