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STOCK COMPENSATION EXPENSE, Assumptions (Details) - $ / shares
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Assumptions used in the Black-Scholes option-pricing model [Abstract]      
Risk-free interest rate 2.02% 1.41% 1.41%
Expected option life 5 years 4 months 10 days 5 years 5 years
Expected stock price volatility 18.40% 16.48% 17.20%
Dividend yield 3.16% 4.03% 3.53%
Weighted average fair value of options granted during the year (in dollars per share) $ 2.32 $ 1.06 $ 1.25