Note 4 - Other Long-term Assets (Tables)

12 Months Ended

Dec. 31, 2020

Notes Tables

Schedule of Other Assets, Noncurrent [Table Text Block]

	December 31,
	2020		2019
Advanced coal royalties	$	6,449	$	6,105
Marketable equity securities available for sale, at fair value (restricted)*		—		2,296
Other		1,809		1,923
Total other assets	$	8,258	$	10,324