PENSION PLAN - Summary of activity (Details) - Pension Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Change in benefit obligation
Benefit obligation at beginning of year	$ 11,435	$ 9,416
Interest cost	365	392	$ 352
Actuarial loss	(54)	99
Assumption changes	1,255	1,769
Benefits paid	(286)	(241)
Benefit obligation at end of year	12,715	11,435	9,416
Change in plan assets:
Fair value of plan assets at beginning of year	6,165	5,238
Actual return on plan assets	511	808
Employer contribution	706	360
Benefits paid	(286)	(241)
Fair value of plan assets at end of year	7,096	6,165	$ 5,238
Funded status	(5,619)	(5,270)
Unrecognized net actuarial loss	6,591	5,883
Prepaid pension cost recognized	972	613
Accumulated benefit obligation	$ 12,715	$ 11,435