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Benefit Plans (Significant Assumptions Used to Estimate Fair Value of Stock Options and SARS) (Details)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]      
Weighted average expected life of the securities granted (in years) 5 years 8 months 4 days 5 years 7 months 11 days 5 years 7 months 11 days
Estimate of the underlying common stock's volatility 40.39% 39.88% 39.58%
Expected dividend yield 2.10% 1.50%   
Risk free interest rate 1.00% 2.20% 2.60%