PENSIONS AND OTHER POST-RETIREMENT BENEFITS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Pension Benefits
Components of the net periodic benefit cost
Service cost	$ 1,887	$ 1,734	$ 3,774	$ 3,468
Interest cost	3,114	3,335	6,228	6,670
Expected return on plan assets	(3,655)	(3,936)	(7,310)	(7,872)
Amortization of prior service cost	0	3	0	6
Recognized actuarial loss	2,166	502	4,332	1,004
Net periodic benefit cost	3,512	1,638	7,024	3,276
Pension Benefits | Cost of sales
Components of the net periodic benefit cost
Net periodic benefit cost	2,000	900	4,000	1,900
Pension Benefits | Selling, general, and administrative expenses
Components of the net periodic benefit cost
Net periodic benefit cost	1,500	700	3,000	1,400
Other Benefits
Components of the net periodic benefit cost
Service cost	4	6	8	12
Interest cost	80	91	160	182
Expected return on plan assets	0	0	0	0
Amortization of prior service cost	(72)	(561)	(144)	(1,122)
Recognized actuarial loss	92	154	184	308
Net periodic benefit cost	$ 104	$ (310)	$ 208	$ (620)