DERIVATIVE INSTRUMENTS 2 (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	$ 40,544	$ 36,539
Fair value Derivative Liabilities	64,056	42,693
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	40,544	36,539
Fair value Derivative Liabilities	64,056	42,693
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivatives-Energy Related-Current [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	28,807	24,242
Fair value Derivative Liabilities	33,254	23,828
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivatives-Energy Related-NonCurrent [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	11,737	12,297
Fair value Derivative Liabilities	22,696	5,403
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Derivatives-Other [Member]
Derivatives, Fair Value [Line Items]
Fair value Derivative Assets	0	0
Fair value Derivative Liabilities	$ 8,106	$ 13,462