Derivative financial instruments - Outstanding Currency, Forward Exchange Contracts (Detail) - Foreign Currency Forward Contracts - Notional Sell Amounts - USD ($) $ in Thousands	Apr. 30, 2023	Apr. 30, 2022
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	$ 162,822	$ 169,360
Euro
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	109,595	96,436
British pound
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	28,614	38,478
Mexican Peso
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	871
Japanese yen
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	21,619	10,848
Hong Kong dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	0	7,727
Australian dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	0	295
Singapore dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	60	198
Taiwan Dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	0
Others
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	2,063	15,378
Notional Amounts of foreign currency derivative contracts	584,675	631,871
Euro
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	155,683	337,291
British pound
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	123,134	80,853
Mexican Peso
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	27,577
Japanese yen
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	26,700	39,294
Hong Kong dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	148,303	55,666
Australian dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	8,892	9,269
Singapore dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	19,759	17,899
Taiwan Dollar
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	8,000
Others
Derivative [Line Items]
Notional Amounts of foreign currency derivative contracts	$ 66,627	$ 91,599