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Stockholders' Equity and Stock Plans - Valuation Assumptions (Details)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.37% 1.67% 2.04%
Expected dividend yield on common stock 2.02% 1.75% 1.70%
Expected life in years 6 years 6 years 6 years
Expected price volatility 25.56% 28.06% 30.32%