Derivatives and Hedging Activities - Additional Information (Detail) £ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Jan. 31, 2020 USD ($)	Jan. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)	Jul. 31, 2018 USD ($)	May 13, 2010 GBP (£)
Derivatives, Fair Value [Line Items]
Document Period End Date			Jan. 31, 2020
Derivative Maturities			18 months
Derivative, Notional Amount	$ 16,529,000		$ 16,529,000		$ 29,389,000
Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months	(878,000)		(878,000)		(805,000)
Cash Flow Hedge Gain (Loss) Reclassified to Earnings	105,000	$ 240,000	486,000	$ 287,000
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	(20,000)	$ (10,000)	(28,000)	$ (43,000)
Accumulated other comprehensive loss	(72,490,000)		(72,490,000)		(71,254,000)	$ (56,401,000)
Senior Unsecured Notes [Member]
Derivatives, Fair Value [Line Items]
Derivative, Amount of Hedged Item | £							£ 45,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Derivative, Notional Amount	13,046,000		13,046,000		26,013,000
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member]
Derivatives, Fair Value [Line Items]
Accumulated other comprehensive loss	$ 12,994		$ 12,994		$ 12,440