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Share-Based Compensation and Capital Stock Weighted Average Assumptions Of Black-Scholes Option-Pricing Model (Details) (USD $)
6 Months Ended
Jun. 30, 2014
Jun. 30, 2013
Share-Based Compensation and Capital Stock [Line Items]    
Risk-free interest rate (percent) 1.56% 0.73%
Dividend yield (percent) 1.62% 2.01%
Contractual life 7 years 7 years
Weighted average fair value of options granted (in dollars per share) $ 8.82 $ 9.89
Stock Options [Member]
   
Share-Based Compensation and Capital Stock [Line Items]    
Expected volatility (percent) 25.01% 38.14%
Expected life of stock option 4 years 6 months 4 years 6 months
Requisite service period 4 years 4 years