COMPONENTS OF QUARTERLY AND YEAR TO DATE NET PERIODIC BENEFIT COSTS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Qualified Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost, benefits earned during the period	$ 0	$ 0
Interest cost on projected benefit obligation	385	403
Expected return on plan assets	(826)	(785)
Amortization of unrecognized transition obligation	0	0
Amortization of unrecognized prior service cost	0	0
Amortization of unrecognized net loss	43	58
Net periodic pension benefit	(398)	(324)
Supplemental Pension Plan
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost, benefits earned during the period	0	0
Interest cost on projected benefit obligation	12	12
Expected return on plan assets	0	0
Amortization of unrecognized prior service cost	0	0
Amortization of unrecognized net loss	2	1
Net periodic pension benefit	14	13
Postretirement Plan, Medical and Life
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost, benefits earned during the period	0	0
Interest cost on projected benefit obligation	3	4
Expected return on plan assets	0	0
Amortization of unrecognized prior service cost	(55)	(55)
Amortization of unrecognized net loss	28	29
Net periodic pension benefit	$ (24)	$ (22)