SUPPLEMENTAL EXECUTIVE RETIREMENT PLAN - Components of Net Periodic Pension Cost (Details) - Supplemental Executive Retirement Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Components of net periodic pension cost [Abstract]
Service cost	$ 419	$ 273	$ 1,276	$ 819
Interest cost	291	321	874	963
Amortization of prior service cost	275	275	824	824
Amortization of loss	1,234	545	3,702	1,636
Total net periodic benefit cost	$ 2,219	$ 1,414	$ 6,676	$ 4,242