BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Pension Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	$ 1,039	$ 1,026
Interest cost	1,361	1,406
Expected return on plan assets	(3,121)	(2,960)
Amortization of unrecognized net loss	263	377
Amortization of prior service cost	14	11
Net periodic (benefit) cost	(444)	(140)
Post-retirement Benefits [Member]
Net periodic benefit cost [Abstract]
Service cost	0	0
Interest cost	19	20
Expected return on plan assets	0	0
Amortization of unrecognized net loss	2	(1)
Amortization of prior service cost	(45)	(45)
Net periodic (benefit) cost	$ (24)	$ (26)