PENSION AND POSTRETIREMENT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pension Benefits
Components of net periodic benefit cost (credit)
Service cost	$ 566	$ 484	$ 1,695	$ 1,475
Interest cost	1,662	1,673	5,010	5,024
Expected return on plan assets	(2,305)	(2,395)	(6,942)	(7,208)
Amortization of prior service credit	(64)	(79)	(191)	(241)
Amortization of transition asset	(78)	(19)	(234)	(61)
Settlement loss	765	0	765	0
Amortization of loss (gain)	951	772	2,850	2,334
Net periodic cost	1,497	436	2,953	1,323
Postretirement Benefits
Components of net periodic benefit cost (credit)
Service cost	3	3	9	9
Interest cost	19	19	57	56
Expected return on plan assets	0	0	0	0
Amortization of prior service credit	0	0	0	0
Amortization of transition asset	0	0	0	0
Settlement loss	0	0	0	0
Amortization of loss (gain)	(14)	(13)	(42)	(38)
Net periodic cost	$ 8	$ 9	$ 24	$ 27