NONCONTROLLING INTERESTS - Net Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 92,846	$ 208,318	$ 157,721
SGP
Noncontrolling Interest
Net income attributable to noncontrolling interest	33	74	56
Non-Affiliates (ARLP'S Non-Affiliate Limited Partners)
Noncontrolling Interest
Net income attributable to noncontrolling interest	92,840	208,260	$ 157,665
Affiliate (Cavalier Minerals)
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ (27)	$ (16)