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Earnings Per Share (Narrative) (Details) - USD ($)
12 Months Ended
Apr. 30, 2021
Apr. 30, 2020
Apr. 30, 2019
May 25, 2021
Aug. 22, 2019
Nov. 28, 2018
Nov. 30, 2016
Earnings Per Share [Abstract]              
Potentially dilutive shares 0 0          
Equity, Class of Treasury Stock [Line Items]              
Treasury Stock, Shares, Acquired 200,046   745,232        
Treasury Stock, Value, Acquired, Cost Method     $ 50,000,000.0        
Share Repurchase Program 2016              
Equity, Class of Treasury Stock [Line Items]              
Stock Repurchase Program, Authorized Amount             $ 50,000,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount $ 0            
Share Repurchase Program 2018              
Equity, Class of Treasury Stock [Line Items]              
Stock Repurchase Program, Authorized Amount           $ 14,000,000  
Share Repurchase Program 2019              
Equity, Class of Treasury Stock [Line Items]              
Stock Repurchase Program, Authorized Amount         $ 50,000,000    
Stock Repurchase Program, Remaining Authorized Repurchase Amount 30,000,000.0            
Treasury Stock, Value, Acquired, Cost Method $ 20,000,000.0            
Share Repurchase Program 2019 | Subsequent Event              
Equity, Class of Treasury Stock [Line Items]              
Stock Repurchase Program Cancelled Authorized Repurchase Amount       $ 30,000,000      
Share Repurchase Program 2021 | Subsequent Event              
Equity, Class of Treasury Stock [Line Items]              
Stock Repurchase Program, Authorized Amount       $ 100,000,000