Equity (Details) - USD ($) $ in Thousands		3 Months Ended
	Sep. 12, 2019	Oct. 31, 2019	Oct. 31, 2018	Oct. 31, 2017
Equity (Textual)
Proceeds from the exercise of stock options		$ 276
Common Class B
Equity (Textual)
Repurchase of aggregate shares		8,000,000
Class B common stock shares repurchased			729,110
Aggregate purchase price of shares repurchased			$ 3,900
Shares remained available for repurchase under the stock repurchase program		6,900,000
Common Class B | 2015 Stock Option and Incentive Plan [Member]
Equity (Textual)
Number of common stock available for grant of awards	400,000
Proceeds from the exercise of stock options				$ 300
Proceeds from the exercise of stock options, shares				32,551