Stock-Based Compensation (Details 3) - Stock options - USD ($)	12 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Options Outstanding
Total Intrinsic Value (in dollars)	$ 3,133,000	$ 4,616,000
Options Exercisable
Total Intrinsic Value (in dollars)	$ 1,555,000
Range of Exercise Prices, $17.04
Additional information related to stock options outstanding
Exercise price low end of range (in dollars per share)	$ 17.04
Exercise price high end of range (in dollars per share)	$ 17.04
Options Outstanding
Number Outstanding (in shares)	52,500
Weighted Average Remaining Contractual Life	27 months
Weighted Average Exercise Price (in dollars per share)	$ 17.04
Options Exercisable
Number Exercisable (in shares)	35,000
Weighted Average Remaining Contractual Life (in months)	27 months
Weighted Average Exercise Price (in dollars per share)	$ 17.04
Range of Exercise Prices, $13.81 - $36.70
Additional information related to stock options outstanding
Exercise price low end of range (in dollars per share)	31.81
Exercise price high end of range (in dollars per share)	$ 36.70
Options Outstanding
Number Outstanding (in shares)	55,000
Weighted Average Remaining Contractual Life	44 months
Weighted Average Exercise Price (in dollars per share)	$ 34.03
Options Exercisable
Number Exercisable (in shares)	10,000
Weighted Average Remaining Contractual Life (in months)	39 months
Weighted Average Exercise Price (in dollars per share)	$ 31.81
Range of Exercise Prices, $17.04 - $36.70
Additional information related to stock options outstanding
Exercise price low end of range (in dollars per share)	17.04
Exercise price high end of range (in dollars per share)	$ 36.70
Options Outstanding
Number Outstanding (in shares)	107,500
Weighted Average Exercise Price (in dollars per share)	$ 25.73
Options Exercisable
Number Exercisable (in shares)	45,000
Weighted Average Exercise Price (in dollars per share)	$ 20.32