Summary of Changes in Contract Liabilities Related to Gift Card Program (Detail) $ in Thousands	6 Months Ended
	Oct. 27, 2018 USD ($)
Gift Cards [Line Items]
Gift card liabilities balance as of April 28, 2018	$ 323,465
Gift card breakage	(8,045)
Gift card redemptions	(99,620)
Gift card issuances	88,699
Gift card liabilities balance as of October 27, 2018	214,352
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 October 27, 2018	302,846
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 October 27, 2018	$ (88,494)