v2.3.0.15
Stock Plans (Details) (USD $)
9 Months Ended
Sep. 30, 2011
Sep. 30, 2010
Restricted Stock
  
Stock Plans  
Share-based compensation arrangement by share-based payment award, restricted stock units (in shares)291,912844,706
Share-based compensation arrangement by share-based payment award, restricted stock units, weighted-average per share price (in dollars per share)$ 70.59$ 42.93
Restricted Stock for Stock Based Compensation Company Executives
  
Stock Plans  
Share-based compensation arrangement by share-based payment award, award vesting period (in years)3Y3Y
Restricted Stock for Stock Based Compensation Company Directors Initial Grant
  
Stock Plans  
Share-based compensation arrangement by share-based payment award, award vesting period (in years)5Y5Y
Restricted Stock for Stock Based Compensation Company Directors Other Than Initial Grant
  
Stock Plans  
Share-based compensation arrangement by share-based payment award, award vesting period (in years)first anniversary of the grantfirst anniversary of the grant
Stock Options
  
Stock Plans  
Share-based compensation arrangement by share-based payment award, award vesting period (in years)3Y3Y
Share-based compensation arrangement by share-based payment award, options awarded (in shares)548,3911,140,303
Share-based compensation arrangement by share-based payment award, options, weighted average grant date fair value (in dollars per share)$ 70.76$ 42.78
Share-based compensation arrangement by share-based payment award, award expiration period (in years)10Y10Y