Earnings Per Share (Details) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Apr. 30, 2015	Apr. 30, 2014	Apr. 30, 2015	Apr. 30, 2014
Weighted-average number of shares used in the calculation of basic and diluted earnings per share
Basic weighted-average number of shares	23,034	22,680	22,867	21,763
Effect of dilutive securities:
Stock options	20	105	33	108
Non-vested restricted Class B common stock	414	238	359	1,022
Diluted weighted-average number of shares	23,468	23,023	23,259	22,893