Stockholders' Equity - Additional Information (Detail) - USD ($)	12 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Stock Based Compensation And Stockholders Equity [Line Items]
Total compensation expenses	$ 18,950,000	$ 17,000,000	$ 12,500,000
Obligation to repurchase common stock	0
Total unrecognized compensation costs	$ 18,918,000
Period for recognition of compensation cost not yet recognized	1 year 9 months 21 days
Tax benefits from stock compensation expense	$ 4,550,000	4,930,000	4,625,000
Stock repurchase program authorized amount		250,000,000
Stock repurchase program expiration date	Jun. 19, 2020
Amount Of Shares Repurchased Under The Programme	$ 0	0
Restricted Stock Units (RSUs)
Stock Based Compensation And Stockholders Equity [Line Items]
Total compensation expenses	$ 18,950,000	$ 17,000,000	$ 12,399,000
2010 Equity Incentive Plan
Stock Based Compensation And Stockholders Equity [Line Items]
Number of shares authorized under stock option plan	2,000,000
Number of shares available to be granted	1,211,385
2016 Equity Incentive Plan
Stock Based Compensation And Stockholders Equity [Line Items]
Number of shares authorized under stock option plan	2,000,000
Number of shares available to be granted	1,378,729