Income Taxes - Summary of Change in Balance of Unrecognized Income Tax Benefits (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Income Taxes [Line Items]
Balance at beginning of year	$ 3,754	$ 1,754	$ 1,754
Additions based on tax positions related to the current year
Additions for tax positions of prior years		2,000
Reductions for tax positions of prior years
Settlements	(3,754)
Lapses of statutes of limitations
Balance at end of year		$ 3,754	$ 1,754