Summary of Significant Accounting Policies (Details)	3 Months Ended
	Jul. 28, 2012 Y
Buildings and building equipment [Member]
Property and equipment amortized over the estimated useful life of related assets
Property and equipment, useful life, minimum	20
Property and equipment, useful life, maximum	45
Computer hardware, software and equipment [Member]
Property and equipment amortized over the estimated useful life of related assets
Property and equipment, useful life, minimum	3
Property and equipment, useful life, maximum	10
Furniture and fixtures [Member]
Property and equipment amortized over the estimated useful life of related assets
Property and equipment, useful life, average	10