Stock-Based Compensation Expense in Selling and Administrative Expenses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 26, 2013	Oct. 27, 2012	Oct. 26, 2013	Oct. 27, 2012
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-Based Compensation Expense	$ 1,459	$ 5,942	$ 5,681	$ 10,982
Selling and administrative expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Restricted Stock Expense	584	4,564	1,293	8,191
Restricted Stock Units Expense	1,042	764	5,994	1,470
Stock Option Expense	$ (167)	$ 614	$ (1,606)	$ 1,321