DERIVATIVE FINANCIAL INSTRUMENTS Impact of Derivative Instruments on Statement of Operations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commodity Price Risk Management, net
Derivative [Line Items]
Net settlements	$ 12,913	$ 49,416	$ 17,243
Net change in fair value of unsettled derivatives	(36,818)	(17,077)	28,847
Total Derivative Gain (Loss)	(23,905)	32,339	46,090
Sales From Natural Gas Marketing
Derivative [Line Items]
Net settlements	446	2,170	2,970
Net change in fair value of unsettled derivatives	429	(1,658)	(161)
Total Derivative Gain (Loss)	875	512	2,809
Cost of Natural Gas Marketing
Derivative [Line Items]
Net settlements	(257)	(2,029)	(2,571)
Net change in fair value of unsettled derivatives	(412)	1,601	(85)
Total Derivative Gain (Loss)	$ (669)	$ (428)	$ (2,656)