Provision for Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Oct. 31, 2017	Oct. 31, 2016
Income Tax Disclosure [Abstract]
Effective income tax rate	31.40%	32.00%
Expected decrease in unrecognized tax benefits due to resolution of uncertain tax positions	$ 2,730
Expected decrease in interest due to resolution of uncertain tax positions	$ 370