Consolidated Condensed Balance Sheets (Parenthetical) (USD $)	Apr. 30, 2013	Jul. 31, 2012	Apr. 30, 2012
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000	25,000,000
Preferred stock, shares issued	0	0	0
Preferred stock, shares outstanding	0	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000	100,000,000
Common stock, shares issued	40,861,919	40,531,204	40,516,476
Treasury stock, shares	4,949,111	4,949,111	4,468,181