Current report filing

STOCK-BASED COMPENSATION - Additional Information (Detail)

v2.4.0.8
STOCK-BASED COMPENSATION - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Number of active share-based award plan 1    
Total income tax benefit recognized for stock-based compensation expense $ 9.8 $ 8.7 $ 7.8
Excess tax benefits from stock-based compensation plans (1.7) (1.2) (3.5)
Stock options vesting percentage for each year of completed service 33.00%    
Stock options expiration periods 10 years    
Stock options valuation method description We use the binomial model to calculate the fair value of stock options granted on or after January 1, 2006.    
Shares Outstanding At 100 Of Target [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Sharebased Payment Award Options Nonvested Number Of Shares 181,803    
Shares Outstanding At 200 Of Target [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Sharebased Payment Award Options Nonvested Number Of Shares 363,606    
Stock Options
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total intrinsic value of stock options exercised 38.3 9.9 14.7
Total unrecognized compensation cost 5.5    
Total unrecognized compensation cost, weighted-average period of recognition 1 year 6 months    
Stock Options | Maximum
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock awards vesting periods 3 years    
Nonvested Stock
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Total weighted-average fair value on the vesting date 19.9 12.1 10.3
Total weighted-average grant date fair value 12.8 11.7 12.1
Total unrecognized compensation cost $ 24.7    
Total unrecognized compensation cost, weighted-average period of recognition 1 year 10 months 24 days    
Nonvested Stock | Maximum
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock awards vesting periods 3 years    
Nonvested Stock | Minimum
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Stock awards vesting periods 1 year