Annual report pursuant to Section 13 and 15(d)

Employee Stock Plans - Additional Information (Detail)

v3.19.2
Employee Stock Plans - Additional Information (Detail)
12 Months Ended
Apr. 30, 2019
USD ($)
$ / shares
shares
Apr. 30, 2018
USD ($)
$ / shares
shares
Apr. 30, 2017
USD ($)
$ / shares
shares
Apr. 30, 2016
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Payments of tax withholdings on restricted stock | $ $ 20,698,000 $ 3,794,000 $ 4,758,000  
Shares repurchased during the period, value | $ $ 58,070,000 $ 36,865,000 $ 33,579,000  
Treasury Stock, Common        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares repurchased during the period 809,074 984,079 1,140,576  
Shares repurchased during the period, value | $ $ 37,400,000 $ 33,100,000 $ 28,800,000  
ESPP        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Maximum number of shares reserved for issuance 3,000,000      
Authorized payroll deductions 15.00%      
Fair market price of common stock 85.00%      
Authorized payroll deductions, value | $ $ 25,000      
Shares available for future issuance 1,000,000      
Employees stock purchased 169,299 198,749 207,141  
Employees stock purchased, price per share | $ / shares $ 42.05 $ 31.77 $ 20.93  
Time Based Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period 4 years      
Market Based Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period 3 years      
Shares outstanding 600,000      
Total unrecognized compensation cost related to non-vested awards | $ $ 11,000,000      
Performance Based Restricted Stock Unit        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period 3 years      
Shares outstanding 0      
Restricted Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Shares outstanding 1,460,000 1,730,000 1,581,000 1,506,000
Total unrecognized compensation cost related to non-vested awards | $ $ 35,000,000      
Expected cost recognized over weighted-average period 2 years 4 months 24 days      
Shares repurchased during the period to pay for taxes 356,879 108,089    
Payments of tax withholdings on restricted stock | $ $ 20,700,000 $ 3,800,000    
Stock Options        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Proceeds from issuance of common stock upon exercise of employee stock options | $ $ 200,000 $ 600,000 $ 800,000  
Stock Options | Common Stock        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock issued for stock options exercised 6,720 41,075 53,955  
Stock Incentive Plan        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock incentive plan, additional number of shares 5,500,000      
Maximum number of shares reserved for issuance 11,200,000      
Issuance of full-value stock awards limitation, required ratio to stock options 2.3