EMPLOYEE BENEFIT PLANS (Included in AOCI) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Nonunion Defined Benefit Pension Plan
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial (gain) loss		$ 4,034
Total		4,034
Supplemental Benefit Plan
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial (gain) loss	$ 127	405
Total	127	405
Postretirement Health Benefit Plan
Pre-tax amounts included in accumulated other comprehensive loss that have not yet been recognized in net periodic benefit cost
Unrecognized net actuarial (gain) loss	(3,024)	7,416
Unrecognized prior service credit	(1)	(34)
Total	$ (3,025)	$ 7,382