Note 11 - Major Customers (Tables)

6 Months Ended

Jun. 30, 2026

Notes Tables

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

		*For the Three Months Ended June 30,*																*For the Six Months Ended June 30,*
		*2026*								*2025*								*2026*								*2025*
(In thousands)		*Revenues*				*Percent*				*Revenues*				*Percent*				*Revenues*				*Percent*				*Revenues*				*Percent*
Foresight Energy Resources LLC ("Foresight") ⁽¹⁾		$	13,830				26	%		$	9,796				21	%		$	27,327				27	%		$	26,256				26	%
Alpha Metallurgical Resources, Inc. ⁽¹⁾		$	13,517				26	%		$	13,184				28	%		$	27,218				27	%		$	26,360				26	%
Alabama Kanu Holdings, LLC ⁽¹⁾		$	5,856				11	%		$	5,284				11	%		$	10,586				11	%		$	8,543				8	%