EMPLOYEE BENEFITS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Components of net periodic benefit cost and other amounts recognized in Other Comprehensive Income
Service cost	$ 293	$ 288	$ 878	$ 865
Interest cost	185	199	555	596
Expected return on plan assets	(521)	(482)	(1,561)	(1,447)
Amortization of net loss	113	102	338	305
Amortization of prior service credit	(20)	(20)	(58)	(58)
Amortization of transition obligation	0	0	0	0
Net periodic benefit cost	50	87	152	261
SERP Benefits
Components of net periodic benefit cost and other amounts recognized in Other Comprehensive Income
Service cost	54	44	159	132
Interest cost	26	27	78	79
Expected return on plan assets	0	0	0	0
Amortization of net loss	12	6	38	20
Amortization of prior service credit	0	0	0	0
Amortization of transition obligation	7	7	21	21
Net periodic benefit cost	$ 99	$ 84	$ 296	$ 252