Quarterly report pursuant to Section 13 or 15(d)

Share-based Compensation - Additional Information (Detail)

v2.4.0.8
Share-based Compensation - Additional Information (Detail) (USD $)
1 Months Ended
May 31, 2013
Feb. 28, 2013
Stock options exercisable
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted options 661,745 774,231
Exercise price $ 19.78 $ 21.60
Vesting period 4 years 4 years
Percentage of stock options to be vested   75.00%
Stock options exercisable | Vesting on the 16th quarter
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Percentage of stock options to be vested 25.00% 25.00%
Stock options exercisable | Vesting over 15 quarters
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Percentage of stock options to be vested 75.00%  
Restricted Stock
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting period 4 years 4 years
Granted shares of restricted stock 382,058 387,118
Fair value restricted stock $ 19.78 $ 21.60
Performance Based Restricted Stock
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Granted shares of restricted stock   70,000
Fair value restricted stock   $ 21.60
Vested Quarterly Over One Year | Restricted Stock
   
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Vesting period   1 year
Granted shares of restricted stock   154,337
Fair value restricted stock   $ 21.60