Segment Information - Schedule of Adjusted EBITDA (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Tax	$ (73,493)	$ 118,734
Interest Expense, net	1,701	904
Depreciation, Depletion and Amortization	121,556	56,997
Stock-Based Compensation	12,859	5,118
Merger-Related Expenses	49,182	0
Loss on extinguishment of debt	11,680	0
Adjusted EBITDA	123,485	181,753
Other, Corporate and Eliminations
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Tax	(129,460)	(23,112)
Interest Expense, net	1,701	904
Depreciation, Depletion and Amortization	12,218	8,369
Stock-Based Compensation	12,859	5,118
Merger-Related Expenses	49,182
Loss on extinguishment of debt	11,680
Adjusted EBITDA	(41,820)	(8,721)
High CV Thermal | Operating Segments
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Tax	93,506	130,517
Interest Expense, net	0	0
Depreciation, Depletion and Amortization	51,290	45,484
Stock-Based Compensation	0	0
Merger-Related Expenses	0
Loss on extinguishment of debt	0
Adjusted EBITDA	144,796	176,001
Metallurgical | Operating Segments
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Tax	(65,472)	(4,938)
Interest Expense, net	0	0
Depreciation, Depletion and Amortization	45,889	2,052
Stock-Based Compensation	0	0
Merger-Related Expenses	0
Loss on extinguishment of debt	0
Adjusted EBITDA	(19,583)	(2,886)
PRB | Operating Segments
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Tax	15,911	0
Interest Expense, net	0	0
Depreciation, Depletion and Amortization	10,780	0
Stock-Based Compensation	0	0
Merger-Related Expenses	0
Loss on extinguishment of debt	0
Adjusted EBITDA	26,691	0
Baltimore Marine Terminal | Operating Segments
Segment Reporting Information [Line Items]
Earnings (Loss) Before Income Tax	12,022	16,267
Interest Expense, net	0	0
Depreciation, Depletion and Amortization	1,379	1,092
Stock-Based Compensation	0	0
Merger-Related Expenses	0
Loss on extinguishment of debt	0
Adjusted EBITDA	$ 13,401	$ 17,359