NONCONTROLLING INTERESTS - Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 40,337	$ 26,765	$ 92,643	$ 100,476
Affiliate (SGP)
Noncontrolling Interest
Net income attributable to noncontrolling interest	14	9	32	35
Non-Affiliates (ARLP's non-affiliate limited partners)
Noncontrolling Interest
Net income attributable to noncontrolling interest	40,279	26,763	92,571	100,468
Affiliate (Cavalier Minerals)
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 44	$ (7)	$ 40	$ (27)