CONTINGENCIES AND COMMITMENTS (Details Textuals) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2012
Accrual for Environmental Loss Contingencies Disclosure [Abstract]
Accrual for Environmental Loss Contingencies	$ 12,632
Class Action Lawsuit [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, at Carrying Value	$ 22,500

Total costs accrued as of the balance sheet date for environmental loss contingencies.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

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-Name Statement of Position (SOP)

-Number 96-1

-Paragraph 161

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

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