PENSION AND POSTRETIREMENT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Pension Benefits
Components of net periodic benefit cost
Service cost	$ 484	$ 352	$ 1,475	$ 1,078
Interest cost	1,673	2,107	5,024	6,351
Expected return on plan assets	(2,395)	(2,477)	(7,208)	(7,473)
Amortization of prior service credit	(79)	(99)	(241)	(303)
Amortization of transition asset	(19)	(69)	(61)	(211)
Amortization of actuarial loss (gain)	772	431	2,334	1,302
Net periodic cost	436	245	1,323	744
Postretirement Benefits
Components of net periodic benefit cost
Service cost	3	3	9	9
Interest cost	19	22	56	66
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
Amortization of actuarial loss (gain)	(13)	(14)	(38)	(42)
Net periodic cost	$ 9	$ 11	$ 27	$ 33