DERIVATIVE INSTRUMENTS 2 (Details) (Not Designated as Hedging Instrument [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	$ 4,622	$ 766
Fair value Derivative Liabilities	(7,302)	(10,456)
Commodity Contract [Member] | Derivatives-Energy Related-Current [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	4,346	464
Fair value Derivative Liabilities	(410)	(2,615)
Commodity Contract [Member] | Derivatives-Energy Related-NonCurrent [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	276	302
Fair value Derivative Liabilities	(7)	(80)
Interest Rate Contract [Member] | Derivatives-Other [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	0	0
Fair value Derivative Liabilities	$ (6,885)	$ (7,761)