Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Weighted-average number of shares used in the calculation of basic and diluted earnings per share
Basic weighted-average number of shares	22,799	22,818	22,867	22,783
Effect of dilutive securities:
Stock options		52		40
Non-vested restricted Class B common stock		355	17	332
Diluted weighted-average number of shares	22,799	23,225	22,884	23,155