Schedule of Unaudited Proforma Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Jul. 31, 2011	Jul. 31, 2010
Business Acquisition [Line Items]
Net sales	$ 2,817,400	$ 2,673,976
Net income	$ 109,431	$ 119,676
Basic earnings per common share	$ 1.96	$ 2.09
Diluted earnings per common share	$ 1.96	$ 2.08