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Stockholders' Equity (Weighted Average Assumptions) (Details) - $ / shares
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rate   1.44%
Stock Options    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Dividend yield 1.18%  
Expected volatility 27.08%  
Risk-free interest rate 2.65%  
Expected holding period (years) 5 years  
Black-Scholes value (in dollars per share) $ 6.38