Revenue From Contracts With Customers - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 2,280,018	$ 1,261,034	$ 879,462
Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,018,662	1,092,022	772,662
Power Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,302,313	689,983	629,568
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	411,103	308,380	85,568
Metallurgical
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	305,246	93,659	57,526
Terminal Revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	78,915	65,193	66,810
Freight Revenue
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	182,441	103,819	39,990
Domestic | Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	944,534	590,941	506,554
Domestic | Power Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	908,666	571,622	486,215
Domestic | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	19,231	12,377	18,150
Domestic | Metallurgical
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16,637	6,942	2,189
Export | Coal
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,074,128	501,081	266,108
Export | Power Generation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	393,647	118,361	143,353
Export | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	391,872	296,003	67,418
Export | Metallurgical
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 288,609	$ 86,717	$ 55,337