Income Taxes - Schedule of Deferred Income Tax Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2014	Jul. 31, 2013	Jul. 31, 2012	Jul. 31, 2011
Deferred income tax assets:
Bad debt reserve	$ 2,188	$ 2,812
Accrued expenses	2,937	7,096
Stock options and restricted stock	2,131	2,786
Charitable contributions	1,230	2,415
Impairment	25,745	25,566
Depreciation	7,566	989
Unrealized gain	163	507
Net operating loss	126,093	144,001
Credits	3,123	2,845
Total deferred income tax assets	171,176	189,017
Valuation allowance	(151,975)	(167,328)	(204,977)	(206,669)
DEFERRED INCOME TAX ASSETS, NET	$ 19,201	$ 21,689