Schedule of Components of Provision (Benefit) for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2010
Income Taxes [Line Items]
Federal	$ 57,736	$ 48,943	$ 55,462
State and local	4,658	250	9,337
Foreign			(11)
Total current expense	62,394	49,193	64,788
Federal	(3,387)	(2,989)	(3,430)
State and local	(55)	150	(29)
Total deferred benefit	(3,442)	(2,839)	(3,459)
Income Taxes	$ 58,952	$ 46,354	$ 61,329