PENSION AND POST RETIREMENT BENEFIT PLANS (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Components of net periodic pension benefit Gain    
Interest and service cost $ 2,250 $ 2,375
Expected return on plan assets (3,197) (3,108)
Amortization of net loss 940 610
Net periodic loss/(benefit) $ (7) $ (123)