EARNINGS PER LIMITED PARTNER UNIT (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
EARNINGS PER LIMITED PARTNER UNIT
NET INCOME ATTRIBUTABLE TO ARLP	$ 158,057	$ 191,185
General partner's interest in net income attributable to ARLP		(1,384)
Limited partners' interest in net income attributable to ARLP	158,057	189,801
Distributions to participating securities	(1,680)	(2,432)
Undistributed earnings attributable to participating securities	(1,448)	(2,979)
Net income (loss) attributable to ARLP available to limited partners	$ 154,929	$ 184,390
Weighted-average limited partner units outstanding - basic (in units)	127,670,897	127,289,340
Weighted-average limited partner units outstanding - diluted (in units)	127,671,000	127,289,000
Earnings per limited partner unit - basic (in dollars per unit)	$ 1.21	$ 1.45
Earnings per limited partner unit - diluted (in dollars per unit)	$ 1.21	$ 1.45
Anti-dilutive under the treasury stock method (in units)	2,175,000	3,147,000