Income Taxes - Schedule of Deferred Income Tax Assets and Deferred Income Tax Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2012	Jul. 31, 2011
Income Taxes [Line Items]
Bad debt reserve	$ 2,751	$ 3,893
Accrued expenses	17,666	15,478
Exercise of stock options and lapsing of restrictions on restricted stock	1,342	1,814
Charitable contributions	7,266	12,397
Impairment	25,671	27,552
Depreciation	409	3,900
Unrealized gain	1,102
Net operating loss	183,061	142,376
Credits	2,595	2,300
Total deferred income tax assets	241,863	209,710
Unrealized loss		(3,041)
Valuation allowance	(204,977)	(206,669)
DEFERRED INCOME TAX ASSETS, NET	$ 36,886