COMPONENTS OF QUARTERLY AND YEAR TO DATE NET PERIODIC BENEFIT COSTS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Qualified Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	$ 298	$ 353	$ 594	$ 707
Interest cost on projected benefit obligation	470	457	940	914
Expected return on plan assets	(756)	(824)	(1,511)	(1,647)
Amortization of unrecognized transition obligation	0	0	0	0
Amortization of unrecognized prior service cost	2	3	4	5
Amortization of unrecognized net loss	383	369	767	737
Net periodic pension cost	397	358	794	716
Supplemental Pension Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	10	11	21	22
Interest cost on projected benefit obligation	13	12	26	24
Expected return on plan assets	0	0	0	0
Amortization of unrecognized prior service cost	0	0	0	0
Amortization of unrecognized net loss	7	13	13	26
Net periodic pension cost	30	36	60	72
Postretirement Plan, Medical and Life [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost, benefits earned during the period	12	12	24	24
Interest cost on projected benefit obligation	18	16	35	32
Expected return on plan assets	0	0	0	0
Amortization of unrecognized prior service cost	(25)	(24)	(49)	(48)
Amortization of unrecognized net loss	6	2	12	4
Net periodic pension cost	$ 11	$ 6	$ 22	$ 12