FAIR VALUE MEASUREMENTS (Change in Fair Value at Level 3) (Details) - Commodity Contract [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Change in Fair Value Measurement Categorized in Level 3 [Roll Forward]
Balance at beginning of period	$ 9,678	$ (3,751)	$ 1,521	$ (23,365)
Purchases	0	0	0	0
Settlements	(10,111)	4,972	(11,311)	3,667
Unrealized loss included in earnings	2,338	1,468	11,695	22,387
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance at end of period	$ 1,905	$ 2,689	$ 1,905	$ 2,689