Note 12 - Major Customers - Concentration Risk (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Alpha Metallurgical Resources [Member]
Net sales	[1]	$ 20,902	$ 24,218
Alpha Metallurgical Resources [Member] | Revenue Benchmark [Member] | Customer Concentration Risk [Member]
Revenue, percent (1)	[1]	27.00%	24.00%
Foresight Energy Resources [Member]
Net sales	[1]	$ 12,846	$ 12,529
Foresight Energy Resources [Member] | Revenue Benchmark [Member] | Customer Concentration Risk [Member]
Revenue, percent (1)	[1]	17.00%	13.00%

[1] Revenues from Alpha Metallurgical Resources, Inc. and Foresight are included within the Partnership's Mineral Rights segment.