EMPLOYEE BENEFITS (Details 3) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plan [Member]
Components of net periodic benefit cost (credit)
Service cost	$ 1,421	$ 1,401	$ 1,246
Interest cost	8,426	7,380	8,159
Expected return on plan assets	(9,892)	(9,464)	(9,495)
Amortization of prior service credit	(399)	(393)	(54)
Amortization of transition asset	(276)	(272)	(269)
Settlement loss	810	229	0
Curtailment gain	(409)	0	0
Amortization of loss (gain)	1,719	3,223	2,417
Net periodic cost (benefit)	1,400	2,104	2,004
Other Postretirement Benefit Plan [Member]
Components of net periodic benefit cost (credit)
Service cost	11	18	18
Interest cost	87	92	111
Expected return on plan assets	0	0	0
Amortization of prior service credit	0	(254)	(353)
Amortization of transition asset	0	0	0
Settlement loss	0	0	0
Curtailment gain	0	0	0
Amortization of loss (gain)	(57)	(5)	(7)
Net periodic cost (benefit)	$ 41	$ (149)	$ (231)