BENEFIT PLANS (Components of Net Periodic Benefit Cost- Pension Benefits) (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Components of Net Periodic Benefit Cost
Service cost	$ 1,429	$ 1,654
Interest cost	8,876	9,057
Expected return on plan assets	(14,797)	(12,096)
Amortization of prior service cost (credit)	335	335
Amortization of actuarial loss	2,457	1,824
Net periodic benefit cost (credit)	(1,700)	774
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ 2,792	$ 2,159