XML 38 R32.htm IDEA: XBRL DOCUMENT v2.4.0.8
Employee Stock Plans - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended 6 Months Ended
Oct. 31, 2013
Oct. 31, 2012
Oct. 31, 2013
Oct. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Cash proceeds from exercise of stock options $ 2.0 $ 0.8 $ 3.8 $ 1.0
Common Stock
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock issued for stock options exercised 126,244 111,230 315,123 135,511
Stock Incentive Plan 2008
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Stock incentive plan, maximum number of shares issuable 5,700,000   5,700,000  
Issuance of full-value stock awards limitation, required ratio to stock options 1.91   1.91  
Stock Options
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost related to non-vested awards 0.3   0.3  
Expected cost recognized over weighted-average period     8 months 12 days  
Stock issued for stock options exercised     315,000  
Time Based Restricted Stock | Minimum
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Vesting period     3 years  
Time Based Restricted Stock | Maximum
       
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]        
Total unrecognized compensation cost related to non-vested awards 3.1   3.1  
Vesting period     3 years  
Shares outstanding 300,000   300,000  
Restricted Stock
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Total unrecognized compensation cost related to non-vested awards 23.0   23.0  
Expected cost recognized over weighted-average period     2 years 3 months 18 days  
Shares repurchased during the period 1,025 9,080 101,399 186,206
Common stock repurchased, value $ 0.1 $ 0.1 $ 2.0 $ 2.6