Sales Information by Product (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
Segment Reporting Information [Line Items]
Net sales	$ 998,834	$ 867,193	$ 1,878,959	$ 1,756,418
Consumable and printed products
Segment Reporting Information [Line Items]
Net sales	707,578	586,757	1,309,788	1,174,315
Equipment and software
Segment Reporting Information [Line Items]
Net sales	212,634	206,920	416,516	433,962
Other
Segment Reporting Information [Line Items]
Net sales	$ 78,622	$ 73,516	$ 152,655	$ 148,141