Discontinued Operations - Schedule of Assets and Liabilities of Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	Jul. 31, 2011	Jul. 31, 2010
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 23,875	$ 13,142
Genie And Subsidiaries [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	23,875
Restricted cash and cash equivalents	163
Trade accounts receivable, net	26,124
Prepaid expenses	2,158
Deferred income tax assets, net-current portion	1,019
Other current assets	3,001
Property, plant and equipment, net	335
Goodwill	3,663
Deferred income tax assets, net-long-term portion	1,795
Other assets	1,007
ASSETS OF DISCONTINUED OPERATIONS	63,140
Trade accounts payable	16,537
Accrued expenses	7,475
Income taxes payable	1,663
Other current liabilities	91
Other liabilities	60
LIABILITIES OF DISCONTINUED OPERATIONS	$ 25,826