FAIR VALUE MEASUREMENTS (Change in Fair Value at Level 3) (Details) - Commodity Contract [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 1,521	$ (23,365)
Purchases	0	0
Settlements	(15,222)	(22,055)
Unrealized loss included in earnings	17,244	46,941
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at end of period	$ 3,543	$ 1,521