Revenue From Contracts With Customers - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	$ 553,432	$ 540,666	$ 1,590,841	$ 1,872,286
Coal
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	462,489	449,618	1,319,738	1,574,096
Power Generation
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	226,796	206,277	671,172	747,334
Industrial
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	151,465	180,785	434,206	590,196
Metallurgical
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	84,228	62,556	214,360	236,566
Terminal Revenue
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	23,740	22,676	60,288	80,755
Freight Revenue
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	63,406	68,372	198,888	217,435
Other Revenue
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	3,797		11,927
Domestic | Coal
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	174,454	180,219	560,017	517,039
Domestic | Power Generation
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	163,769	169,143	515,159	476,598
Domestic | Industrial
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	2,485	11,076	13,636	29,814
Domestic | Metallurgical
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	8,200	0	31,222	10,627
Export | Coal
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	288,035	269,399	759,721	1,057,057
Export | Power Generation
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	63,027	37,134	156,013	270,736
Export | Industrial
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	148,980	169,709	420,570	560,382
Export | Metallurgical
Disaggregation of Revenue [Line Items]
Total Revenue from Contracts with Customers	$ 76,028	$ 62,556	$ 183,138	$ 225,939