Annual report pursuant to Section 13 and 15(d)

Stock Option and Purchase Plans - Additional Information (Detail)

v2.4.0.8
Stock Option and Purchase Plans - Additional Information (Detail) (USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Period of options granted 5 years      
Share price $ 51.00 $ 19.07 $ 25.95  
The weighted average fair value of options vested $ 6.20 $ 6.18 $ 3.54  
Total fair value of options that vested during the year $ 1,000,000 $ 1,000,000 $ 600,000  
Total compensation costs related to non-vested awards 3,500,000      
Weighted average period 2 years 6 months      
Options outstanding 1,409,777 1,521,275 1,661,445 1,904,232
Weighted Average Fair Value of Options Granted $ 23.22 $ 9.93 $ 12.65  
Employee Stock [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share price $ 35.16      
Investment as percentage of cash compensation 20.00%      
Common stock price to market value 85.00%      
Cash compensation limit $ 21,250      
Number of shares employees had subscribed to purchase 51,253      
Weighted Average Fair Value of Options Granted $ 9.31 $ 4.99 $ 3.96  
Director [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Period of options granted 6 months      
Key Employee [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Period of options granted 5 years      
Maximum [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share based payment award options exercisable period 10 years      
Stock Incentive Plan [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share based payment award options exercisable period 10 years      
Period of options granted 5 years      
Options outstanding 1,136,733      
Options available for future grant 531,516      
Directors Stock Option Plan [Member]
       
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share based payment award options exercisable period 10 years      
Period of options granted 6 months      
Options outstanding 273,044      
Options available for future grant 145,555