Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017	Jul. 31, 2016
Postemployment Benefits [Abstract]
Employer match and administrative fees for 401(k) plan	$ 2,689	$ 1,797	$ 917
Investments under employees deferred compensation plan	$ 43,316	$ 28,095