Derivatives and Hedging Activities (Details 2) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Apr. 30, 2011	Jul. 31, 2012	Jul. 31, 2011
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)		$ 15,211	$ (17,659)
Net Investment Hedging [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Reclassified From Accumulated OCI Into Income (Effective Portion)
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)
Net Investment Hedging [Member] | Foreign Exchange Contract [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)		(1,041)	(4,589)
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)
Net Investment Hedging [Member] | Foreign Exchange Contract [Member] | Investment and other income - net [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Reclassified From Accumulated OCI Into Income (Effective Portion)
Net Investment Hedging [Member] | Foreign Currency Denominated Debt [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)		15,705	(13,070)
Net Investment Hedging [Member] | Foreign Currency Denominated Debt [Member] | Investment and other income - net [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Reclassified From Accumulated OCI Into Income (Effective Portion)
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)
Net Investment Hedging [Member] | Foreign Currency Intercompany Debt [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Recognized in OCI on Derivative (Effective Portion)		547
Amount of Gain or (Loss) Recognized in Income on Derivative (Ineffective Portion)
Net Investment Hedging [Member] | Foreign Currency Intercompany Debt [Member] | Investment and other income - net [Member]
Pre-tax effects of derivative instruments as cash flow hedges
Amount of Gain or (Loss) Reclassified From Accumulated OCI Into Income (Effective Portion)