Stock Option Plans (Status For Options Contain Vesting Provisions) (Details) (USD $)	12 Months Ended
	Jul. 31, 2011
Stock Option Plans
Non - vested Options at July31, 2010	407,453
Non - vested Options, Granted	482,250
Non - vested Options, Vested	(189,913)
Non - vested Options, Cancelled	(6,915)
Non - vested Options at July 31, 2011	692,875
Non - vested Weighted Average Grant Date Fair Value at July 31, 2010	$ 12.89
Non - vested Weighted Average Grant Date Fair Value, Granted	$ 18.45
Non - vested Weighted Average Grant Date Fair Value, Vested	$ 12.27
Non - vested Weighted Average Grant Date Fair Value, Canceled	$ 15.42
Non - vested Weighted Average Grant Date Fair Value at July 31, 2011	$ 16.90