NONCONTROLLING INTERESTS - Net Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 49,551	$ 16,047
SGP
Noncontrolling Interest
Net income attributable to noncontrolling interest	17	6
Non-Affiliates (ARLP's non-affiliate limited partners)
Noncontrolling Interest
Net income attributable to noncontrolling interest	49,386	16,043
Affiliate (Cavalier Minerals)
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 148	$ (2)