EMPLOYEE BENEFIT PLANS - Obligation and Funded Status (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Change in benefit obligation:
Benefit obligation at beginning of year	$ 19,289	$ 18,947
Interest cost	756	775	$ 757
Actuarial loss (gain)	159	139
Benefits paid	(782)	(800)
Curtailment gain	0	0
Other, change in actuarial assumptions	1,247	228
Benefit obligation at end of year	20,669	19,289	18,947
Change in plan assets:
Fair value of plan assets at beginning of year	15,090	14,223
Actual return on plan assets	2,424	910
Employer contribution	750	750
Benefits paid	(782)	(797)
Adjustment to fair value of plan assets	4	4
Fair value of plan assets at end of year	17,486	15,090	$ 14,223
Funded status	(3,183)	(4,199)
Accounts recognized on balance sheet as:
Total liabilities	(3,183)	(4,199)
Amounts recognized in accumulated other comprehensive income (loss) consist of:
Net loss	$ 6,227	$ 6,498