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 Contingency [Line Items]
Income tax expense (benefit)	$ 4,408	$ 28,960	$ 13,002	$ 42,138