Provision for Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Income Tax [Line Items]
Maximum percentage of tax benefits realized upon ultimate settlement			50.00%
Decreases in unrecognized tax benefits resulting from settlement	$ 4,041		$ 5,683
Income tax benefit related to gross uncertain tax benefit releases, net	1,624		2,632
Interest and penalties related to uncertain tax benefits	291		586
Effective income tax rate	28.00%	22.20%	31.60%	30.40%
Expected decrease in unrecognized tax benefits due to resolution of uncertain tax positions			3,660
Expected decrease in interest and penalties due to resolution of uncertain tax positions			895
Minimum
Income Tax [Line Items]
Expected gross unrecognized tax benefits decrease			900
Expected decrease in interest and penalties			400
Maximum
Income Tax [Line Items]
Expected gross unrecognized tax benefits decrease			6,500
Expected decrease in interest and penalties			$ 3,800