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Stock-Based Compensation (Tables)
3 Months Ended
Mar. 31, 2013
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]  
Weighted Average Assumptions Used in Calculating the Fair Value of Stock Option
The fair value of the stock option grants issued in the three months ended March 31, 2013 was calculated with the following weighted average assumptions:
 
Risk free interest rate
1.3
%
Expected life of option in years
6.5

Expected dividend yield
3.2
%
Expected volatility
29.9
%