Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 4,553	$ 3,423
Inventories, reserves	$ 1,864	$ 1,552
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	40,531,204	40,334,973
Treasury stock, shares	4,949,111	4,264,804