PENSIONS AND OTHER POSTRETIREMENT BENEFITS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Benefits
Components of the net periodic benefit cost
Service cost	$ 1,802	$ 2,628	$ 3,604	$ 5,256
Interest cost	2,955	2,799	5,910	5,598
Expected return on plan assets	(3,131)	(3,249)	(6,262)	(6,498)
Amortization of prior service cost	4	9	8	18
Recognized actuarial loss	1,027	283	2,054	566
Net periodic benefit cost	2,657	2,470	5,314	4,940
Other Benefits
Components of the net periodic benefit cost
Service cost	12	119	24	238
Interest cost	114	320	228	640
Amortization of prior service cost	(844)	(303)	(1,688)	(606)
Recognized actuarial loss	246	166	492	332
Net periodic benefit cost	$ (472)	$ 302	$ (944)	$ 604