BENEFIT PLANS (Components of Net Periodic Benefit Cost- Pension Benefits) (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Components of Net Periodic Benefit Cost
Service cost	$ 1,429	$ 1,654	$ 2,858	$ 3,308
Interest cost	8,875	9,058	17,751	18,115
Expected return on plan assets	(14,797)	(12,096)	(29,594)	(24,192)
Amortization of prior service cost	335	335	670	670
Amortization of actuarial loss	2,456	1,823	4,913	3,647
Net periodic benefit cost (credit)	(1,702)	774	(3,402)	1,548
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ 2,791	$ 2,158	$ 5,583	$ 4,317