FAIR VALUE OF FINANCIAL ASSETS AND FINANCIAL LIABILITIES, LEVEL THREE INPUTS (Details) (Forward Contracts [Member], Level 3 [Member], Natural Gas (in MMdts) [Member], USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Assets	$ 27
Liabilities	$ 270
Minimum [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Forward price (in dollars per dt)	(0.60)
Maximum [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Forward price (in dollars per dt)	(0.19)
Weighted Average [Member]
Fair Value Inputs, Assets And Liabilities, Quantitative Information [Line Items]
Forward price (in dollars per dt)	(0.38)