Derivatives and Hedging Activities - Fair Values of Derivative Instruments in Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Apr. 30, 2018	Jul. 31, 2017
Designated as hedging instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	$ 523	$ 1,067
Liability Derivatives	54,944	54,849
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	523	1,067
Designated as hedging instruments [Member] | Cash flow hedging | Foreign exchange contract [Member] | Other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	368	1,569
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	54,576	53,280
Not designated as hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	5	287
Liability Derivatives	2	7
Not designated as hedging Instruments [Member] | Foreign exchange contract [Member] | Prepaid expenses and other current assets [Member]
Derivatives, Fair Value [Line Items]
Asset Derivatives	5	287
Not designated as hedging Instruments [Member] | Foreign exchange contract [Member] | Other current liabilities [Member]
Derivatives, Fair Value [Line Items]
Liability Derivatives	$ 2	$ 7