SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN - Components of Net Periodic Pension Cost (Details) - Supplemental Executive Retirement Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Components of net periodic pension cost [Abstract]
Service cost	$ 273	$ 288
Interest cost	321	403
Amortization of prior service cost	275	399
Amortization of loss	545	411
Total net periodic benefit cost	$ 1,414	$ 1,501