PENSION AND OTHER POSTRETIREMENT PLANS (Components of net periodic benefit cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Change in benefit obligation:
Beginning benefit obligation	$ 2,715	$ 2,118
Interest cost	75	87	$ 93
Actuarial (gain)/loss	276	631
Benefits paid	(356)	(121)
Ending benefit obligation	2,710	2,715	2,118
Change in plan assets (primarily equity and fixed income investments and money market funds), at fair value:
Beginning plan assets	2,472	2,151
Actual return	233	415
Employer contribution		27
Benefits paid	(356)	(121)
Ending plan assets	2,349	2,472	2,151
Funded status at end of year	(361)	(243)
SERP Benefits
Change in benefit obligation:
Beginning benefit obligation	991	924
Interest cost	27	37	34
Actuarial (gain)/loss	84	164
Benefits paid	(134)	(134)
Ending benefit obligation	968	991	924
Change in plan assets (primarily equity and fixed income investments and money market funds), at fair value:
Beginning plan assets	914	885
Actual return	99	163
Benefits paid	(134)	(134)
Ending plan assets	879	914	$ 885
Funded status at end of year	$ (89)	$ (77)