EMPLOYEE BENEFIT PLAN - Components of net periodic benefit cost (Details) - Retirement Income Plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 247	$ 411	$ 741	$ 1,234
Expected return on plan assets	(378)	(395)	(1,132)	(1,186)
Amortization of net losses	202	246	606	739
Net periodic benefit cost	$ 71	$ 262	$ 215	$ 787