EMPLOYEE BENEFITS (Details 3) - USD ($) $ in Thousands		12 Months Ended
	Jan. 31, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plan [Member]
Components of net periodic benefit cost (credit)
Service cost		$ 2,178	$ 1,953	$ 1,421
Interest cost		6,624	6,676	8,426
Expected return on plan assets		(9,025)	(9,555)	(9,892)
Amortization of prior service credit		(311)	(318)	(399)
Amortization of transition asset		(214)	(258)	(276)
Settlement loss	$ 600	633	16	810
Special termination benefits		0	235	0
Curtailment gain		0	0	(409)
Amortization of loss (gain)		3,645	3,273	1,719
Net periodic cost (benefit)		3,530	2,022	1,400
Other Postretirement Benefit Plan [Member]
Components of net periodic benefit cost (credit)
Service cost		11	12	11
Interest cost		76	74	87
Expected return on plan assets		0	0	0
Amortization of prior service credit		0	0	0
Amortization of transition asset		0	0	0
Settlement loss		0	0	0
Special termination benefits		0	0	0
Curtailment gain		0	0	0
Amortization of loss (gain)		(58)	(51)	(57)
Net periodic cost (benefit)		$ 29	$ 35	$ 41