Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Apr. 30, 2016	Apr. 30, 2015	Apr. 30, 2016	Apr. 30, 2015
Weighted-average number of shares used in the calculation of basic and diluted earnings per share
Basic weighted-average number of shares	22,635	23,034	22,790	22,867
Effect of dilutive securities:
Stock options		20		33
Non-vested restricted Class B common stock	45	414	26	359
Diluted weighted-average number of shares	22,680	23,468	22,816	23,259