Schedule of Changes in Unrecognized Tax Benefit (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Beginning balance	$ 32,174	$ 31,039	$ 30,235
Tax positions related to prior years: Additions	562	1,817	760
Tax positions related to prior years: Reductions	(284)	(1,062)	(1,883)
Tax positions related to current year: Additions	3,995	3,713	4,095
Settlements	(1,364)	(2,642)	(817)
Lapses in statute of limitations	(1,183)	(691)	(1,351)
Ending balance	$ 33,900	$ 32,174	$ 31,039