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Stock-Based Compensation - Weighted-Average Assumptions Used in Option Pricing Model (Details) (Stock Option, USD $)
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Stock Option
     
Schedule of Share-Based Compensation Award, Options, Fair Value Assumption Inputs      
Weighted average grant date fair value of options granted (in dollars per share) $ 3.54 $ 4.06 $ 4.30
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]      
Expected volatility 30.61% 37.46% 36.36%
Expected dividend yield 3.00% 3.35% 3.17%
Risk-free interest rate 0.88% 1.99% 3.05%
Expected life of options (in years) 5 years 6 months 6 days 7 years 10 months 6 days 7 years 11 months 19 days