Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Additional Information (Detail)

v3.22.2
Financial Instruments - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Apr. 30, 2022
Apr. 30, 2021
Apr. 30, 2020
Financial Instrument [Line Items]      
Sale/maturities of available-for-sale marketable securities $ 79.3 $ 60.6 $ 4.8
Unrealized loss relates to equity securities 27.3   8.2
Unrealized gains relates to equity securities   32.7  
Not Designated as Hedge Instrument | Foreign Exchange Forward Contracts      
Financial Instrument [Line Items]      
Foreign currency gains (losses) (0.2) 2.7 $ (0.3)
Not Designated as Hedge Instrument | Foreign Exchange Forward Contracts | Income Taxes And Other Receivables | Derivatives Purchased      
Financial Instrument [Line Items]      
Derivative notional amount 89.7 69.4  
Not Designated as Hedge Instrument | Foreign Exchange Forward Contracts | Income Taxes And Other Receivables | Derivatives Sold      
Financial Instrument [Line Items]      
Derivative notional amount $ 35.8 $ 44.9  
Available-for-sale Marketable Securities | Minimum      
Financial Instrument [Line Items]      
Marketable securities remaining maturity 1 month    
Available-for-sale Marketable Securities | Maximum      
Financial Instrument [Line Items]      
Marketable securities remaining maturity 21 months