BENEFIT PLANS (Components of Net Periodic Benefit Cost- Other Postretirement Benefits) (Details) - Other Postretirement Benefits [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Components of Net Periodic Benefit Cost
Service cost	$ 292	$ 281	$ 875	$ 842
Interest cost	315	302	945	907
Amortization of prior service cost (credit)	(1,059)	(1,059)	(3,177)	(3,177)
Amortization of actuarial (gain) loss	(397)	(438)	(1,190)	(1,313)
Net periodic benefit cost (credit)	(849)	(914)	(2,547)	(2,741)
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ (1,456)	$ (1,497)	$ (4,367)	$ (4,490)