BENEFIT PLANS (Components of Net Periodic Benefit Cost- Other Postretirement Benefits) (Details) - Other Postretirement Benefit Plans, Defined Benefit [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Components of Net Periodic Benefit Cost
Service cost	$ 265	$ 380
Interest cost	106	242
Amortization of prior service credit	(476)	(980)
Amortization of actuarial gain	(367)	(201)
Net periodic benefit credit	(472)	(559)
Pretax reclassifications from AOCI included in net periodic postretirement benefit credit	$ (843)	$ (1,181)