EMPLOYEE BENEFIT PLAN - Components of net periodic benefit cost (Details) - Multiple Employers Retirement Income Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 412	$ 490	$ 823	$ 980
Expected return on plan assets	(396)	(650)	(791)	(1,300)
Amortization of net losses	247	230	493	460
Net periodic benefit cost	$ 263	$ 70	$ 525	$ 140