Stock-Based Compensation (Details Textual) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions				1 Months Ended	12 Months Ended
	Oct. 13, 2016	Jun. 07, 2016	Dec. 14, 2015	Aug. 31, 2013	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014
Stock Based Compensation (Textual)
Additional shares available stock option incentive plan for grants			100
Weighted-average grant date fair value of options granted during the period						$ 7.94
Reduction of exercise price		$ 2.25
Stock option awards, description					Option awards generally vest on a graded basis over three years of service and have ten-year contractual terms
Total intrinsic value of options exercised during the period						$ 1.3	$ 0.2
Total unrecognized compensation cost					$ 0.6
Total unrecognized compensation cost, Weighted-average period of recognition					1 year 4 months 24 days
Total unrecognized compensation cost related to non-vested stock-based compensation arrangements					$ 3.5
Total unrecognized compensation cost related to non-vested stock-based compensation arrangements, expected weighted-average period					1 year
Total grant date fair value of shares vested					$ 1.3	5.6	8.7
Income tax benefit resulting from tax deductions in excess of compensation cost recognized
Class B common stock [Member]
Stock Based Compensation (Textual)
Shares of common stock reserved for award under 2015 stock option and incentive plan					600
Shares of common stock available for future grants					200
Percentage of reduction in the exercise price				15.29%
Fully vested outstanding options to purchase shares of Class B common stock				32,155
Class B common stock [Member] | Subsequent Event [Member]
Stock Based Compensation (Textual)
Additional shares available stock option incentive plan for grants	100