BENEFIT PLANS (Components of Net Periodic Benefit Cost- Pension Benefits) (Details) - Pension Benefits [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Components of Net Periodic Benefit Cost
Service cost	$ 1,429	$ 1,653	$ 4,287	$ 4,961
Interest cost	8,876	9,057	26,627	27,172
Expected return on plan assets	(14,797)	(12,097)	(44,391)	(36,289)
Amortization of prior service cost	335	335	1,005	1,005
Amortization of actuarial loss	2,457	1,824	7,370	5,471
Net periodic benefit cost (credit)	(1,700)	772	(5,102)	2,320
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ 2,792	$ 2,159	$ 8,375	$ 6,476