Financial Instruments - Outstanding Currency, Forward Exchange Contracts (Detail) $ in Thousands	Jul. 31, 2018 USD ($)
Derivative [Line Items]
Fair Value of foreign currency derivative contracts	$ (239)
Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	309,173
Fair Value of foreign currency derivative contracts	306,350
Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	508,455
Fair Value of foreign currency derivative contracts	505,344
Euro [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	239,642
Fair Value of foreign currency derivative contracts	237,535
Euro [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	201,296
Fair Value of foreign currency derivative contracts	200,285
British Pound [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	41,649
Fair Value of foreign currency derivative contracts	41,182
British Pound [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	70,644
Fair Value of foreign currency derivative contracts	69,429
Japanese Yen [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	22,872
Fair Value of foreign currency derivative contracts	22,641
Japanese Yen [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	43,591
Fair Value of foreign currency derivative contracts	43,113
Australian Dollar [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	185
Fair Value of foreign currency derivative contracts	186
Australian Dollar [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	7,729
Fair Value of foreign currency derivative contracts	7,677
Hong Kong Dollar [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	453
Fair Value of foreign currency derivative contracts	452
Hong Kong Dollar [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	118,507
Fair Value of foreign currency derivative contracts	118,369
Singapore Dollar [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	613
Fair Value of foreign currency derivative contracts	603
Singapore Dollar [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	12,820
Fair Value of foreign currency derivative contracts	12,635
Others [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	3,759
Fair Value of foreign currency derivative contracts	3,751
Others [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	53,868
Fair Value of foreign currency derivative contracts	$ 53,836