DERIVATIVE FINANCIAL INSTRUMENTS (Details 2) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Amount of gains (losses) recognized in income from derivative instruments not designated as hedging instruments
Total	$ (3,300)	$ (1,668)	$ 661	$ (2,661)
Commodity derivatives | Not designated as hedging instruments
Amount of gains (losses) recognized in income from derivative instruments not designated as hedging instruments
Realized cash settlements on hedges	1,137	(1,477)	5,135	(3,278)
Mark-to-market gain (loss) on hedges	(4,437)	(191)	(4,474)	617
Total	$ (3,300)	$ (1,668)	$ 661	$ (2,661)