Annual report pursuant to Section 13 and 15(d)

EMPLOYEE BENEFITS AND STOCK BASED COMPENSATION (Estimated Stock Option on the Date of Grant Fair Value) (Details)

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EMPLOYEE BENEFITS AND STOCK BASED COMPENSATION (Estimated Stock Option on the Date of Grant Fair Value) (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Estimated stock option on the date of grant fair value      
Dividend yield 2.15% 3.36% 3.12%
Expected life in years 2 years 10 months 6 days 2 years 10 months 6 days 2 years 8 months 12 days
Expected volatility 23.35% 22.16% 21.50%
Risk-free interest rate 1.40% 0.83% 0.75%