Note 2 - Revenue from Contracts with Customers:- Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Total Revenue from Contracts with Customers	$ 530,067	$ 292,016	$ 1,671,103	$ 925,998
Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	238,694	152,311	676,834	428,688
Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	233,914	106,249	804,834	375,239
Coal [Member]
Total Revenue from Contracts with Customers	472,608	258,560	1,481,668	803,927
Terminal Revenue [Member]
Total Revenue from Contracts with Customers	14,840	14,108	58,016	49,700
Freight Revenue [Member]
Total Revenue from Contracts with Customers	42,619	19,348	131,419	72,371
Power Generated, Coal [Member] | Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	228,488	146,845	655,834	414,565
Power Generated, Coal [Member] | Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	53,329	26,390	203,364	86,626
Power Generated, Coal [Member] | Coal [Member]
Total Revenue from Contracts with Customers	281,817	173,235	859,198	501,191
Industrial, Coal [Member] | Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	6,670	3,233	17,464	9,470
Industrial, Coal [Member] | Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	117,435	57,534	371,093	230,771
Industrial, Coal [Member] | Coal [Member]
Total Revenue from Contracts with Customers	124,105	60,767	388,557	240,241
Metallurgical, Coal [Member] | Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	3,536	2,233	3,536	4,653
Metallurgical, Coal [Member] | Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	63,150	22,325	230,377	57,842
Metallurgical, Coal [Member] | Coal [Member]
Total Revenue from Contracts with Customers	$ 66,686	$ 24,558	$ 233,913	$ 62,495