Earnings per Limited Partner Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Earnings Per Share [Abstract]
Net Income (Loss)	$ 79,562	$ 59,410	$ 88,656	$ 133,393
Distributions to participating securities	(679)	(719)	(1,339)	(1,545)
Undistributed earnings attributable to participating securities	(15)	0	0	0
Net income attributable to ARLP available to limited partners	$ 78,868	$ 58,691	$ 87,317	$ 131,848
Weighted-average limited partner units outstanding - basic (in units)	128,658,801	128,428,024	128,598,875	128,347,131
Weighted-average limited partner units outstanding - diluted (in units)	128,658,801	128,428,024	128,598,875	128,347,131
Earnings per limited partner unit - basic (in dollars per unit)	$ 0.61	$ 0.46	$ 0.68	$ 1.03
Earnings per limited partner unit - diluted (in dollars per unit)	$ 0.61	$ 0.46	$ 0.68	$ 1.03
Anti-dilutive under the treasury stock method (in units)	495,000	605,000	582,000	715,000

Aggregate amount of net income available to limited partners after allocation to participating securities.

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