Income Taxes (Details 1) - USD ($) $ in Thousands	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2014	Jul. 31, 2013
Deferred income tax assets:
Bad debt reserve	$ 575	$ 550
Accrued expenses	5,327	4,629
Stock options and restricted stock	1,802	1,030
Charitable contributions	1,527	1,277
Impairment	25,746	25,746
Depreciation	6,785	7,232
Unrealized gain	193	138
Net operating loss	122,849	125,223
Credits	3,192	2,892
Total deferred income tax assets	167,996	168,717
Valuation allowance	(158,442)	(155,393)	$ (151,975)	$ (167,328)
Deferred tax assets, net of valuation allowance	9,554	13,324
Deferred income tax liabilities:
Unrealized loss	42
NET DEFERRED INCOME TAX ASSETS	$ 9,512	$ 13,324