BENEFIT PLANS (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Pension Plans, Defined Benefit [Member]
Components of Net Periodic Benefit Cost
Service cost	$ 1,336	$ 1,212	$ 2,672	$ 2,425
Interest cost	9,126	11,036	18,252	22,073
Expected return on plan assets	(12,890)	(13,684)	(25,781)	(27,368)
Amortization of prior service cost (credit)	(10)	12	(21)	24
Amortization of actuarial (gain) loss	1,541	5,455	3,082	10,909
Net periodic pension/postretirement benefit cost (credit)	(897)	4,031	(1,796)	8,063
Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	1,531	5,467	3,061	10,933
Other Postretirement Benefit Plans, Defined Benefit [Member]
Components of Net Periodic Benefit Cost
Service cost	280	474	561	947
Interest cost	303	626	605	1,243
Amortization of prior service cost (credit)	(1,059)	(1,058)	(2,118)	(2,116)
Amortization of actuarial (gain) loss	(437)	23	(875)	19
Net periodic pension/postretirement benefit cost (credit)	(913)	65	(1,827)	93
Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income
Pretax reclassification from AOCI included in net periodic pension/postretirement benefit cost (credit)	$ (1,496)	$ (1,035)	$ (2,993)	$ (2,097)