EMPLOYEE BENEFIT PLAN - Components of net periodic benefit cost (Details) - Retirement Income Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 247	$ 412	$ 494	$ 823
Expected return on plan assets	(377)	(396)	(754)	(791)
Amortization of net losses	202	247	404	493
Net periodic benefit cost	$ 72	$ 263	$ 144	$ 525