Note 9 - Revenues (Tables)

9 Months Ended

Sep. 30, 2021

Revenue from Contract with Customer [Abstract]

Schedule of disaggregation of revenue

	Three months ended September 30,				Nine months ended September 30,
(In thousands)	2021		2020		2021		2020
Coal Sales
North American revenues	$	47,954	$	27,284	$	105,611	$	89,795
Export revenues, excluding Canada		28,423		12,175		90,278		27,974
Total revenues	$	76,377	$	39,459	$	195,889	$	117,769