BENEFIT PLANS (Components of Net Periodic Benefit Cost- Other Postretirement Benefits) (Details) - Postretirement Benefits [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Components of Net Periodic Benefit Cost
Service cost	$ 339	$ 292
Interest cost	310	315
Amortization of prior service credit	(991)	(1,059)
Amortization of actuarial gain	(324)	(397)
Net periodic benefit cost (credit)	(666)	(849)
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ (1,315)	$ (1,456)