Note 8 - Revenues (Tables)

3 Months Ended

Mar. 31, 2021

Revenue from Contract with Customer [Abstract]

Schedule of disaggregation of revenue

	Three months ended March 31,
(In thousands)	2021		2020
Coal Sales
North American revenues	$	20,107	$	30,532
Export revenues, excluding Canada		23,348		11,403
Total revenues	$	43,455	$	41,935