Financial Instruments - Outstanding Currency, Forward Exchange Contracts (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2015
Derivative [Line Items]
Fair Market Value of foreign currency derivative contracts	$ 3,013
Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	591,351
Fair Market Value of foreign currency derivative contracts	600,519
Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	662,489
Fair Market Value of foreign currency derivative contracts	674,639
Euro [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	372,491
Fair Market Value of foreign currency derivative contracts	378,572
Euro [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	370,074
Fair Market Value of foreign currency derivative contracts	378,887
British Pound [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	124,115
Fair Market Value of foreign currency derivative contracts	127,047
British Pound [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	106,410
Fair Market Value of foreign currency derivative contracts	108,506
Japanese Yen [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	32,306
Fair Market Value of foreign currency derivative contracts	32,271
Japanese Yen [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	20,685
Fair Market Value of foreign currency derivative contracts	20,685
Australian Dollar [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	463
Fair Market Value of foreign currency derivative contracts	475
Australian Dollar [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	7,487
Fair Market Value of foreign currency derivative contracts	7,658
Hong Kong Dollar [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	56,255
Fair Market Value of foreign currency derivative contracts	56,296
Hong Kong Dollar [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	116,757
Fair Market Value of foreign currency derivative contracts	116,852
Singapore Dollar [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	365
Fair Market Value of foreign currency derivative contracts	378
Singapore Dollar [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	10,493
Fair Market Value of foreign currency derivative contracts	10,761
Others [Member] | Foreign Currency Forward Contracts [Member] | Sell [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	5,356
Fair Market Value of foreign currency derivative contracts	5,480
Others [Member] | Foreign Currency Forward Contracts [Member] | Buy [Member]
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	30,583
Fair Market Value of foreign currency derivative contracts	$ 31,290