Revenue From Contracts With Customers - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	$ 2,506,635	$ 2,280,018	$ 1,261,034
Coal
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	2,106,366	2,018,662	1,092,022
Power Generation
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	1,019,180	1,302,313	689,983
Industrial
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	772,642	411,103	308,380
Metallurgical
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	314,544	305,246	93,659
Terminal Revenue
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	106,166	78,915	65,193
Freight Revenue
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	294,103	182,441	103,819
Domestic | Coal
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	717,633	944,534	590,941
Domestic | Power Generation
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	672,509	908,666	571,622
Domestic | Industrial
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	34,453	19,231	12,377
Domestic | Metallurgical
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	10,671	16,637	6,942
Export | Coal
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	1,388,733	1,074,128	501,081
Export | Power Generation
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	346,671	393,647	118,361
Export | Industrial
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	738,189	391,872	296,003
Export | Metallurgical
Disaggregation of Revenue [Line Items]
Revenue and Other Income:	$ 303,873	$ 288,609	$ 86,717