Earnings Per Share - Summary of Weighted-Average Number of Shares used in Calculation of Basic and Diluted Earnings Per Share (Details) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Apr. 30, 2014	Apr. 30, 2013
Weighted-average number of shares used in the calculation of basic and diluted earnings per share
Basic weighted-average number of shares	22,680	20,905	21,763	20,847
Effect of dilutive securities:
Stock options	105		108
Non-vested restricted Class B common stock	238	1,455	1,022	1,331
Diluted weighted-average number of shares	23,023	22,360	22,893	22,178