Provision for Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2016	Jan. 31, 2015
Income Tax [Line Items]
Effective income tax rate	31.30%	31.40%	33.10%	31.10%
Interest and penalties related to uncertain tax benefits	$ 141	$ 147	$ 282	$ 293
Decreases in unrecognized tax benefits resulting from effective settlement				4,506
Income tax benefit related to gross uncertain tax benefit releases, net				2,387
Accrued an additional uncertain tax benefit related to prior tax periods		$ 90		$ 90
Expected decrease in unrecognized tax benefits due to resolution of uncertain tax positions	$ 5,340		5,340
Expected decrease in interest due to resolution of uncertain tax positions			$ 1,182