Annual report pursuant to Section 13 and 15(d)

Financial Instruments - Additional Information (Detail)

v3.19.2
Financial Instruments - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Mar. 31, 2017
Apr. 30, 2019
Apr. 30, 2018
Apr. 30, 2017
Maximum        
Financial Instrument [Line Items]        
Derivative gains included in accumulated other comprehensive income   $ 400,000    
Designated as Hedge Instrument | Interest Rate Swap | Cash Flow Hedge        
Financial Instrument [Line Items]        
Derivative notional amount $ 129,800,000 $ 106,600,000    
Derivative, Maturity Date Jun. 15, 2021      
Interest rate   1.919%    
Not Designated as Hedge Instrument | Foreign Exchange Forward Contracts        
Financial Instrument [Line Items]        
Foreign currency gains (losses)   $ 1,200,000 $ (3,700,000) $ 600,000
Not Designated as Hedge Instrument | Foreign Exchange Forward Contracts | Other Accrued Liabilities | Derivatives Purchased        
Financial Instrument [Line Items]        
Derivative notional amount   51,400,000 80,800,000  
Not Designated as Hedge Instrument | Foreign Exchange Forward Contracts | Other Accrued Liabilities | Derivatives Sold        
Financial Instrument [Line Items]        
Derivative notional amount   $ 40,000,000 $ 78,500,000