FAIR VALUE MEASUREMENTS (Change in Fair Value at Level 3) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Change in Fair Value Measurement Categorized in Level 3 [Roll Forward]
Transfers into Level 3	$ 0	$ 0	$ 0	$ 0
Commodity Contract [Member]
Change in Fair Value Measurement Categorized in Level 3 [Roll Forward]
Balance at beginning of period	493,000	1,905,000	3,543,000	1,521,000
Purchases	0	0	0	0
Settlements	(90,000)	(1,238,000)	(1,093,000)	(12,549,000)
Unrealized loss included in earnings	(21,000)	(852,000)	(2,068,000)	10,843,000
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Balance at end of period	$ 382,000	$ (185,000)	$ 382,000	$ (185,000)