Other Gains (Losses), Net - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Component Of Other Expense Income Nonoperating [Line Items]
Foreign currency exchange gains (losses)	$ (1,436)	$ 29	$ (2,071)	$ 426
Gains (losses) on Trading Securities		1,011	1,876	94
Non Cash
Component Of Other Expense Income Nonoperating [Line Items]
Gains (losses) on Trading Securities		400	(2,700)	(500)
Cash
Component Of Other Expense Income Nonoperating [Line Items]
Gains (losses) on Trading Securities		600	4,600	600
Asia
Component Of Other Expense Income Nonoperating [Line Items]
Realized and unrealized gains (losses) from foreign currency exposures and settled transactions	(700)	(500)	(1,100)	(400)
Europe
Component Of Other Expense Income Nonoperating [Line Items]
Realized and unrealized gains (losses) from foreign currency exposures and settled transactions	1,300	(100)	1,000	(400)
Corporate
Component Of Other Expense Income Nonoperating [Line Items]
Realized and unrealized gains (losses) from foreign currency exposures and settled transactions	$ (2,300)	$ 600	$ (2,200)	$ 1,300