Merger with Arch - Preliminary Allocation Aggregate Purchase Price (Details) - Arch Resources, Inc	Jan. 14, 2025 USD ($)
Business Combination [Line Items]
Total Equity Portion of Purchase Price Consideration	$ 2,481,368,000
Effective Settlement of Pre-Existing Relationships	95,636,000
Total Equity Portion of Purchase Price Consideration	2,577,004,000
Assets Acquired:
Cash and Cash Equivalents	217,593,000
Short-Term Investments	22,969,000
Trade Receivables, net	161,670,000
Other Receivables, net	6,629,000
Inventories	307,175,000
Other Current Assets	13,366,000
Property, Plant and Equipment, net	2,610,672,000
Funds for Asset Retirement Obligations	150,033,000
Other Noncurrent Assets, net	155,763,000
Total Assets Acquired	3,645,870,000
Liabilities Assumed:
Accounts Payable	211,227,000
Current Portion of Long-Term Debt	4,104,000
Other Accrued Liabilities	152,996,000
Long-Term Debt	6,667,000
Postretirement Benefits Other Than Pensions	37,118,000
Pneumoconiosis Benefits	111,313,000
Asset Retirement Obligations	248,773,000
Workers’ Compensation	36,254,000
Salary Retirement	786,000
Deferred Income Taxes	166,173,000
Other Noncurrent Liabilities	93,455,000
Total Liabilities Assumed	1,068,866,000
Net Assets Acquired	$ 2,577,004,000