NONCONTROLLING INTERESTS (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Increase (Decrease) in Partners' Capital
Balance	$ 1,018,274	$ 855,593
Net income	105,934	115,336
Other comprehensive income (loss)	729	(38)
Settlement of directors deferred compensation	(177)	(218)
Vesting of ARLP Long-Term Incentive Plan	(2,719)	(2,991)
Common unit-based compensation	2,892	2,522
Distributions on ARLP common unit-based compensation	(740)	(624)
Contributions to consolidated company from affiliate noncontrolling interest	333
Distributions to AHGP Partners	(54,775)	(49,537)
Distributions paid by consolidated partnership to noncontrolling interest	(27,948)	(25,662)
Balance	1,041,803	894,381
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Partners' Capital
Balance	(15,456)	(4,198)
Other comprehensive income (loss)	314	(9)
Balance	(15,142)	(4,207)
Noncontrolling Interest
Increase (Decrease) in Partners' Capital
Balance	453,496	359,721
Net income	40,404	47,889
Other comprehensive income (loss)	415	(29)
Vesting of ARLP Long-Term Incentive Plan	(2,719)	(2,991)
Common unit-based compensation	2,835	2,443
Distributions on ARLP common unit-based compensation	(740)	(624)
Contributions to consolidated company from affiliate noncontrolling interest	333
Distributions paid by consolidated partnership to noncontrolling interest	(27,948)	(25,662)
Balance	466,076	380,747
Limited Partners' Capital
Increase (Decrease) in Partners' Capital
Balance	580,234	500,070
Net income	65,530	67,447
Settlement of directors deferred compensation	(177)	(218)
Common unit-based compensation	57	79
Distributions to AHGP Partners	(54,775)	(49,537)
Balance	$ 590,869	$ 517,841