BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	May 12, 2017	Dec. 31, 2016
Pension Benefits [Member]
Pension Plans [Abstract]
Defined Benefit Plan, Tax Status [Extensible List]	us-gaap:QualifiedPlanMember		us-gaap:QualifiedPlanMember
Unamortized actuarial gain					$ 1,900
Discount rate					4.40%	4.50%
Net periodic benefit cost [Abstract]
Service cost	$ 1,121	$ 1,067	$ 2,242	$ 2,106
Interest cost	1,415	1,449	2,829	2,812
Expected return on plan assets	(3,705)	(3,407)	(7,410)	(6,529)
Amortization of unrecognized net loss	298	209	596	472
Amortization of prior service cost	(83)	17	(165)	30
Net periodic benefit cost (income)	(954)	(665)	(1,908)	(1,109)
Post-retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	0	0	0	0
Interest cost	17	19	34	38
Expected return on plan assets	0	0	0	0
Amortization of unrecognized net loss	5	2	10	4
Amortization of prior service cost	(44)	(45)	(89)	(89)
Net periodic benefit cost (income)	$ (22)	$ (24)	$ (45)	$ (47)