Note 11 - Revenues (Tables)

12 Months Ended

Dec. 31, 2020

Revenue from Contract with Customer [Abstract]

Schedule of disaggregation of revenue

	Years ended December 31,
(In thousands)	2020		2019		2018
Coal Sales
North American revenues	$	119,981	$	170,927	$	114,508
Export revenues, excluding Canada		48,934		59,286		113,066
Total revenues	$	168,915	$	230,213	$	227,574