Derivative Financial Instruments - Outstanding Currency, Forward Exchange Contracts (Detail) - Foreign Currency Forward Contracts - USD ($) $ in Thousands	Apr. 30, 2021	Apr. 30, 2020
Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	$ 174,189	$ 204,741
Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	581,318	417,913
Euro | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	127,660	110,114
Euro | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	309,020	182,146
British pound | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	21,228	18,987
British pound | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	79,446	58,543
Japanese yen | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	12,228	16,301
Japanese yen | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	38,648	31,934
Australian dollar | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	194	327
Australian dollar | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	10,240	7,647
Hong Kong dollar | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	978	53,935
Hong Kong dollar | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	33,024	60,737
Singapore dollar | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	15	1,082
Singapore dollar | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	18,071	15,620
Others | Sell
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	11,886	3,995
Others | Buy
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	$ 92,869	$ 61,286