EARNINGS PER LIMITED PARTNER UNIT - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
EARNINGS PER LIMITED PARTNER UNIT
Net income (loss) attributable to ARLP	$ 577,190	$ 178,157	$ (129,220)
Distributions to participating securities	(8,527)	(2,334)
Undistributed earnings attributable to participating securities	(10,576)	(2,403)
Net income (loss) attributable to ARLP available to limited partners	$ 558,087	$ 173,420	$ (129,220)
Weighted-average limited partner units outstanding - basic (in units)	127,195,219	127,195,219	127,164,659
Weighted-average limited partner units outstanding - diluted (in units)	127,195,000	127,195,000	127,165,000
Earnings per limited partner unit - basic (in dollars per unit)	$ 4.39	$ 1.36	$ (1.02)
Earnings per limited partner unit - diluted (in dollars per unit)	$ 4.39	$ 1.36	$ (1.02)
Anti-dilutive under the treasury stock method (in units)	3,540,385	1,967,672	773,664