Stock-Based Compensation Expense in Selling and Administrative Expenses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 25, 2014	Jan. 26, 2013	Jan. 25, 2014	Jan. 26, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-Based Compensation Expense	$ 2,466	$ 5,723	$ 8,147	$ 16,705
Selling and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Restricted Stock Expense	390	4,078	1,683	12,269
Restricted Stock Units Expense	1,694	758	7,688	2,228
Stock Option Expense	$ 382	$ 887	$ (1,224)	$ 2,208