Derivatives and Hedging Activities - Fair Values of Derivative Instruments in Consolidated Balance Sheets (Detail) - USD ($)	3 Months Ended
	Oct. 31, 2019	Oct. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated other comprehensive loss	$ (71,283,000)		$ (71,254,000)	$ (56,401,000)
Foreign Currency Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net	381,000	$ 47,000
Prepaid expenses and other current assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Assets	595,000		474,000
Other current liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Liabilities	12,000		5,000
Unrealized gain on cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in other comprehensive loss	196,000	(380,000)
Unrealized gain on cash flow hedges | Designated as hedging instruments [Member] | Prepaid expenses and other current assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Assets	591,000		472,000
Unrealized gain on cash flow hedges | Designated as hedging instruments [Member] | Other current liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Liabilities	0		0
Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in other comprehensive loss	22,000	$ 1,620,000
Net Investment Hedging [Member] | Designated as hedging instruments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated other comprehensive loss	12,462		12,440
Net Investment Hedging [Member] | Designated as hedging instruments [Member] | Prepaid expenses and other current assets [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Assets	0		0
Net Investment Hedging [Member] | Designated as hedging instruments [Member] | Other current liabilities [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivatives Liabilities	$ 0		$ 0