Financial instruments (Details Textuals) (USD $) In Thousands	3 Months Ended	9 Months Ended
Jul. 31, 2011	Jul. 31, 2011
Financial Instruments (Textuals) [Abstract]
Maturity of foreign currency forward contracts	90 days	90 days
Gains/ Losses on foreign exchange contracts	$ 3,532	$ 8,083
Change in fair value of balance sheet positions denominated in foreign currencies	$ 3,640	$ 9,980

Aggregate impact of foreign currency derivatives on earnings for the period. Includes impact of foreign currency cash flow hedge ineffectiveness and the ineffectiveness of fair value hedging derivatives and full change in fair value of the foreign currency derivatives not designated as hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 45

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Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration