Benefit Plans (Detail) (USD $)	12 Months Ended
	Apr. 28, 2013	Apr. 29, 2012	May 01, 2011
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Contributions to defined contribution plans	$ 635,000	$ 606,000	$ 543,000
Contributions to nonqualified deferred compensation plan	145,000	132,000	120,000
Accrued Expense [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Nonqualified deferred compensation plan liability	$ 2,000,000	$ 1,700,000