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Stock Plans and Stock Based Compensation (Details 2) - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]      
Weighted per share average fair value at grant date $ 12.88 $ 8.96 $ 8.32
Risk-free interest rate 1.57% 1.80% 1.91%
Expected dividend yield 3.00% 3.80% 5.14%
Volatility 24.58% 25.32% 30.96%
Expected life (years) 5 years 6 months 6 years 6 years