PENSION PLAN - Summary of activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 31, 2014
Retirement Benefits [Abstract]
Discount rate used to re-measure pension obligation	3.55%	4.05%	4.30%	4.46%
Pension expense	$ 256	$ 273	$ 256
Change in benefit obligation
Benefit obligation at beginning of year	9,021	8,662
Service cost	0	0	0
Interest cost	360	367	315
Actuarial loss	95	4
Assumption changes	775	179
Curtailment impact	0	0
Benefits paid	(193)	(191)
Benefit obligation at end of year	10,058	9,021	8,662
Change in plan assets:
Fair value of plan assets at beginning of year	4,573	4,486
Actual return on plan assets	467	96
Employer contribution	319	182
Benefits paid	(193)	(191)
Fair value of plan assets at end of year	5,166	4,573	$ 4,486
Funded status	(4,892)	(4,448)
Unrecognized net actuarial loss	4,972	4,464
Unrecognized prior service cost	0	0
Prepaid pension cost recognized	80	16
Accumulated benefit obligation	$ 10,058	$ 9,021