BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	May 12, 2017	Dec. 31, 2016
Pension Benefits [Member]
Pension Plans [Abstract]
Unamortized actuarial gain					$ 1,900
Discount rate					4.40%	4.50%
Net periodic benefit cost [Abstract]
Service cost	$ 1,154	$ 1,037	$ 3,396	$ 3,143
Interest cost	1,422	1,453	4,251	4,265
Expected return on plan assets	(3,705)	(3,448)	(11,115)	(9,977)
Amortization of unrecognized net loss	299	148	895	619
Amortization of prior service cost	(60)	13	(225)	43
Net periodic benefit cost (income)	(890)	(797)	(2,798)	(1,907)
Pension Benefits [Member] | Nonqualified Plan [Member] | Unfunded Plan [Member]
Pension Plans [Abstract]
Unfunded initial projected benefit obligation	800		800
Post-retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	0	0	0	0
Interest cost	18	19	52	57
Expected return on plan assets	0	0	0	0
Amortization of unrecognized net loss	5	2	15	6
Amortization of prior service cost	(45)	(45)	(134)	(134)
Net periodic benefit cost (income)	$ (22)	$ (24)	$ (67)	$ (71)