Note 2 - Revenue from Contracts with Customers:- Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Total Revenue from Contracts with Customers	$ 604,882	$ 303,222	$ 1,141,036	$ 633,982
Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	212,695	117,161	438,140	276,377
Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	319,997	142,671	570,920	268,990
Coal [Member]
Total Revenue from Contracts with Customers	532,692	259,832	1,009,060	545,367
Terminal Revenue [Member]
Total Revenue from Contracts with Customers	21,779	17,380	43,176	35,592
Freight Revenue [Member]
Total Revenue from Contracts with Customers	50,411	26,010	88,800	53,023
Power Generated, Coal [Member] | Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	203,846	112,410	427,346	267,720
Power Generated, Coal [Member] | Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	29,594	27,105	150,035	60,236
Power Generated, Coal [Member] | Coal [Member]
Total Revenue from Contracts with Customers	233,440	139,515	577,381	327,956
Industrial, Coal [Member] | Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	8,849	3,401	10,794	6,237
Industrial, Coal [Member] | Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	156,110	92,663	253,658	173,237
Industrial, Coal [Member] | Coal [Member]
Total Revenue from Contracts with Customers	164,959	96,064	264,452	179,474
Metallurgical, Coal [Member] | Domestic Coal Revenue [Member]
Total Revenue from Contracts with Customers	0	1,350	0	2,420
Metallurgical, Coal [Member] | Export Coal Revenue [Member]
Total Revenue from Contracts with Customers	134,293	22,903	167,227	35,517
Metallurgical, Coal [Member] | Coal [Member]
Total Revenue from Contracts with Customers	$ 134,293	$ 24,253	$ 167,227	$ 37,937