XML 79 R60.htm IDEA: XBRL DOCUMENT v2.4.0.6
Stockholder Equity - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Stockholders Equity Note [Line Items]      
Antidilutive securities excluded from determination of diluted earnings per common share 300,000 500,000 500,000
Restricted stock units forfeited 101,000 72,000  
Outstanding exercisable stock options 51,000 101,000 128,000
Stock options exercised 45,040 26,568 28,319
Stock options exercised, aggregate intrinsic value $ 1.7 $ 0.9 $ 0.6
Stock options outstanding, aggregate intrinsic value 2.0    
Restricted Stock
     
Stockholders Equity Note [Line Items]      
Share based compensation 23.4 25.1 29.8
Unrecognized compensation cost $ 50.4 $ 49.8 $ 50.9
Restricted Stock | Maximum
     
Stockholders Equity Note [Line Items]      
Restricted stock and restricted stock unit grants, vesting period 4 years    
Restricted Stock Unit
     
Stockholders Equity Note [Line Items]      
Restricted stock units forfeited 5,905    
Weighted average remaining vesting period 3 months 22 days    
Outstanding restricted stock units 15,567