NONCONTROLLING INTERESTS - Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ 36,259	$ 33,307	$ 52,306	$ 73,711
SGP
Noncontrolling Interest
Net income attributable to noncontrolling interest	12	12	18	26
Non-Affiliates (ARLP's non-affiliate limited partners)
Noncontrolling Interest
Net income attributable to noncontrolling interest	36,249	33,302	52,292	73,705
Affiliate (Cavalier Minerals)
Noncontrolling Interest
Net income attributable to noncontrolling interest	$ (2)	$ (7)	$ (4)	$ (20)