Derivatives and Hedging Activities (Details 3) (Nondesignated [Member], USD $) In Thousands	12 Months Ended
Jul. 31, 2011	Jul. 31, 2010
Gain (loss) on derivative instruments designated as cash flow hedges
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (754)	$ (40)
Foreign Exchange Contract [Member] \| Other income (expense) [Member]
Gain (loss) on derivative instruments designated as cash flow hedges
Amount of Gain or (Loss) Recognized in Income on Derivative	$ (754)	$ (40)

The amount of net gains and losses recognized in income during the period on derivative instruments designated and qualifying as hedging instruments in fair value hedges and related hedged items designated and qualifying in fair value hedges, on derivative instruments designated and qualifying as hedging instruments in cash flow hedges, and on derivative instruments 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 205G

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 133
-Paragraph 44C
-Subparagraph b

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