BENEFIT PLANS (Components of Net Periodic Benefit Cost- Other Postretirement Benefits) (Details) - Postretirement 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	$ 340	$ 291	$ 679	$ 583
Interest cost	310	315	620	630
Amortization of prior service credit	(990)	(1,059)	(1,981)	(2,118)
Amortization of actuarial gain	(325)	(396)	(649)	(793)
Net periodic benefit cost (credit)	(665)	(849)	(1,331)	(1,698)
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ (1,315)	$ (1,455)	$ (2,630)	$ (2,911)