Summary of Significant Accounting Policies (Policies) |
6 Months Ended |
|---|---|
Jun. 30, 2026 | |
| Accounting Policies [Abstract] | |
| Basis of Presentation | Basis of Presentation The accompanying financial statements are presented in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In our opinion, the financial statements include all adjustments (consisting of normal recurring accruals) necessary in order to make the financial statements not misleading. |
| Use of Estimates | Use of Estimates The Company prepares its financial statements in conformity with GAAP, which requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the periods presented. Due to the inherent uncertainty involved in making estimates, actual results could differ from those estimates. |
| Cash, Cash Equivalents and Restricted Cash | Cash, Cash Equivalents and Restricted Cash Cash and cash equivalents include short-term deposits and highly liquid investments that have original maturities of three months or less when purchased and are stated at cost, which approximates fair value. Restricted cash consists of cash that the Company is contractually obligated to maintain in a money market account as collateral for workers' compensation claims. Restricted cash is classified as noncurrent based on the nature of the restriction. |
| Investments | Investments Instruments with maturities greater than three months, but less than twelve months, are included in short-term investments. The Company purchases fixed income securities and certificates of deposits with varying maturities that are classified as available for sale and are carried at fair value. Securities classified as held to maturity securities are those securities that management has the intent and ability to hold to maturity. As of June 30, 2026 and December 31, 2025, short-term investments consisted of $20.2 million and $53.3 million, respectively, in cash and fixed income securities with maturities less than twelve months. The short-term investments as of June 30, 2026 and December 31, 2025 consisted of $10.1 million and $9.9 million, respectively, posted as cash collateral for the self-insured black lung related claims asserted by or on behalf of former employees of Walter Energy, Inc. ("Walter Energy") and its subsidiaries, which were assumed by the Company and relate to periods prior to March 31, 2016. The Company also had $10.1 million and $43.4 million in fixed income securities with maturities less than twelve months as of June 30, 2026 and December 31, 2025, respectively. |
| Revenue Recognition | Revenue Recognition Revenue is recognized when performance obligations under the terms of a contract with the Company's customers are satisfied; for all contracts this occurs when control of the promised goods have been transferred to the Company's customers and risk of loss passes to such customer. For coal shipments to domestic customers via rail or truck, control is typically transferred when the railcar or truck is loaded. For coal shipments to international customers via ocean vessel, control is typically transferred when the vessel is loaded at the Port of Mobile in Alabama. Occasionally, the Company will sell coal stockpiles at the barge loadout or port upon which control, title and risk of loss transfers when stockpiles are segregated. For all steelmaking coal sales under average pricing contracts where pricing is not finalized when revenue is recognized, revenue is recorded based on estimated consideration to be received at the date of the sale. For natural gas sales, control is transferred when the gas has been transferred to the pipeline. Revenue is disaggregated between coal sales within the Company's mining segment and natural gas sales included in all other revenues, as disclosed in Note 12. The Company's coal and gas sales generally include up to 45-day payment terms following the transfer of control of the goods to the customer unless secured by a letter of credit which could include up to 90-day payment terms. The Company typically does not include extended payment terms in its contracts with customers. |
| Trade Accounts Receivable and Allowance for Credit Losses | Trade Accounts Receivable and Allowance for Credit Losses Trade accounts receivable are stated at cost. Trade accounts receivable represent customer obligations that are derived from revenue recognized from contracts with customers. Credit is extended based on an evaluation of the individual customer's financial condition. The Company maintains trade credit insurance on the majority of its customers and the geographic regions of coal shipments to these customers. In some instances, the Company requires letters of credit, cash collateral or prepayments from its customers on or before shipment to mitigate the risk of loss. These efforts have consistently resulted in the Company recognizing no historical credit losses. The Company also has never had to have a claim against its trade credit insurance policy. In order to estimate the allowance for credit losses on trade accounts receivable, the Company utilizes an aging approach in which potential impairment is calculated based on how long a receivable has been outstanding (e.g., current, 1-31 days, 31-60 days, etc.). The Company calculates an expected credit loss rate based on the Company’s historical credit loss rate, the risk characteristics of its customers, and the current steelmaking coal and steel market environments. As of June 30, 2026 and December 31, 2025, the estimated allowance for credit losses was immaterial and did not have a material impact on the Company's financial statements. |