Derivatives and Hedging Activities - Fair Values of Derivative Instruments in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Apr. 30, 2017	Jul. 31, 2016
Designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 419	$ 265
Liability Derivatives	81,501	117,558
Designated as hedging instruments [Member] | Cash flow hedging | Foreign exchange contract [Member] | Prepaid expenses and other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	419	265
Designated as hedging instruments [Member] | Cash flow hedging | Foreign exchange contract [Member] | Other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	276	670
Designated as hedging instruments [Member] | Net investment hedging [Member] | Foreign currency denominated debt [Member] | Prepaid expenses and other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	0	0
Designated as hedging instruments [Member] | Net investment hedging [Member] | Foreign currency denominated debt [Member] | Long term obligations less current maturities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	81,225	116,888
Not designated as hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	481	1,873
Liability Derivatives	32	68
Not designated as hedging Instruments [Member] | Foreign exchange contract [Member] | Prepaid expenses and other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	481	1,873
Not designated as hedging Instruments [Member] | Foreign exchange contract [Member] | Other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 32	$ 68