NONCONTROLLING INTERESTS - Net Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 150,619	$ 92,846	$ 208,318
SGP
Noncontrolling Interest
Net income attributable to noncontrolling interest	53	33	74
Non-Affiliates (ARLP's non-affiliate limited partners)
Noncontrolling Interest
Net income attributable to noncontrolling interest	150,426	92,840	208,260
Affiliate (Cavalier Minerals)
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 140	$ (27)	$ (16)