PENSION AND OTHER POSTRETIREMENT BENEFITS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Pension Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Service cost	$ 468	$ 1,887
Interest cost	2,416	3,114
Expected return on plan assets	(3,612)	(3,655)
Amortization of prior service credit	0	0
Recognized actuarial loss (gain)	123	2,166
Net periodic benefit (income) cost	(605)	3,512
Pension Benefits | Cost of sales
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Net periodic benefit (income) cost	300	2,000
Pension Benefits | Selling, General and Administrative Expenses
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Net periodic benefit (income) cost	300	1,500
Other Benefits
PENSIONS AND OTHER POSTRETIREMENT BENEFITS
Service cost	0	4
Interest cost	49	80
Expected return on plan assets	0	0
Amortization of prior service credit	(280)	(72)
Recognized actuarial loss (gain)	(62)	92
Net periodic benefit (income) cost	$ (293)	$ 104