PENSIONS AND OTHER POST-RETIREMENT BENEFITS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension Benefits
Components of the net periodic benefit cost
Service cost	$ 1,734	$ 2,002
Interest cost	3,335	3,016
Expected return on plan assets	(3,936)	(3,478)
Amortization of prior service cost	3	4
Recognized actuarial loss	502	2,156
Net periodic benefit cost	1,638	3,700
Pension Benefits | Cost of sales [Member]
Components of the net periodic benefit cost
Net periodic benefit cost	900	2,200
Pension Benefits | Selling, general, and administrative expenses [Member]
Components of the net periodic benefit cost
Net periodic benefit cost	700	1,500
Other Benefits
Components of the net periodic benefit cost
Service cost	6	9
Interest cost	91	81
Expected return on plan assets	0	0
Amortization of prior service cost	(561)	(844)
Recognized actuarial loss	154	192
Net periodic benefit cost	$ (310)	$ (562)