PENSIONS AND OTHER BENEFITS - Transition from providing retirement benefits under defined pension plan to defined contribution 401(K) plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Change in projected benefit obligation
Service cost
Interest cost	$ 277	$ 255
Transition from defined pension plan to defined contribution 401(k) plan
Change in projected benefit obligation
Benefit obligation at beginning of year	5,250	6,039
Actuarial gain	$ (977)	$ (860)
Service cost
Interest cost	$ 277	$ 255
Curtailments and settlements
Benefits paid	$ (4,550)	$ (184)
Benefit obligation at end of year		5,250
Change in plan assets
Plan assets at estimated fair value at beginning of year	$ 6,868	6,019
Actual return on plan assets	$ (2,318)	$ 1,033
Contributions by employer
Curtailments and settlements
Benefits paid	$ (4,550)	$ (184)
Fair value of plan assets at end of year		6,868
Funded status and recognized asset included in other assets on the balance sheet		$ 1,618