Accounting Policies (Policies)	3 Months Ended
Mar. 31, 2024
Accounting Policies
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements include the accounts of Arch Resources, Inc. (“Arch Resources”) and its subsidiaries and controlled entities (“Arch” or the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Quarterly Report on Form 10-Q. The Company’s primary business is the production of metallurgical and thermal coal from underground and surface mines located throughout the United States, for sale to steel producers, utility companies, and industrial accounts both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Wyoming and Colorado. All subsidiaries are wholly owned. Intercompany transactions and accounts have been eliminated in consolidation. The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial reporting and U.S. Securities and Exchange Commission regulations. In the opinion of management, all adjustments, consisting of normal, recurring accruals considered necessary for a fair presentation, have been included. Results of operations for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024. These financial statements should be read in conjunction with the audited financial statements and related notes as of and for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the U.S. Securities and Exchange Commission. Certain amounts have been reclassified to conform to the current period's presentation.
Recently Adopted Accounting Guidance	Recently Adopted Accounting Guidance There is no recently issued accounting guidance effective that is expected to have a material impact on the Company’s financial position, results of operations, or liquidity. Recent Accounting Guidance Issued Not Yet Effective In November 2023, the FASB issued ASU 2023-07 Segment Reporting – Improving Reportable Segment Disclosures (Topic 280). The update is intended to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant expenses. The ASU requires disclosure to include significant segment expenses that are regularly provided to the chief operating decision maker (CODM), a description of other segment items by reportable segment, and any additional measures of a segment’s profit or loss used by the CODM when deciding how to allocate resources. The ASU also requires all annual disclosures currently required by Topic 280 to be included in interim periods. The update is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted and requires retrospective application to all prior periods presented in the financial statements. The Company is currently assessing the timing and impact of adopting the updated provisions. In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The amendments are effective for the Company’s annual periods beginning June 1, 2025, with early adoption permitted, and should be applied either prospectively or retrospectively. The Company is currently evaluating the ASU to determine its impact on the Company’s disclosures.

Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2024

The accompanying unaudited condensed consolidated financial statements include the accounts of Arch Resources, Inc. (“Arch Resources”) and its subsidiaries and controlled entities (“Arch” or the “Company”). Unless the context indicates otherwise, the terms “Arch” and the “Company” are used interchangeably in this Quarterly Report on Form 10-Q. The Company’s primary business is the production of metallurgical and thermal coal from underground and surface mines located throughout the United States, for sale to steel producers, utility companies, and industrial accounts both in the United States and around the world. The Company currently operates mining complexes in West Virginia, Wyoming and Colorado. All subsidiaries are wholly owned. Intercompany transactions and accounts have been eliminated in consolidation.

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States for interim financial reporting and U.S. Securities and Exchange Commission regulations. In the opinion of management, all adjustments, consisting of normal, recurring accruals considered necessary for a fair presentation, have been included. Results of operations for the three months ended March 31, 2024 are not necessarily indicative of results to be expected for the year ending December 31, 2024. These financial statements should be read in conjunction with the audited financial statements and related notes as of and for the year ended December 31, 2023 included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2023 filed with the U.S. Securities and Exchange Commission.

Certain amounts have been reclassified to conform to the current period's presentation.

Recently Adopted Accounting Guidance

There is no recently issued accounting guidance effective that is expected to have a material impact on the Company’s financial position, results of operations, or liquidity.

Recent Accounting Guidance Issued Not Yet Effective

In November 2023, the FASB issued ASU 2023-07 Segment Reporting – Improving Reportable Segment Disclosures (Topic 280). The update is intended to improve reportable segment disclosure requirements, primarily through enhanced disclosures about significant expenses. The ASU requires disclosure to include significant segment expenses that are regularly provided to the chief operating decision maker (CODM), a description of other segment items by reportable segment, and any additional measures of a segment’s profit or loss used by the CODM when deciding how to allocate resources. The ASU also requires all annual disclosures currently required by Topic 280 to be included in interim periods. The update is effective for fiscal years beginning after December 15, 2023 and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted and requires retrospective application to all prior periods presented in the financial statements. The Company is currently assessing the timing and impact of adopting the updated provisions.

In December 2023, the FASB issued ASU 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, which includes amendments that further enhance income tax disclosures, primarily through standardization and disaggregation of rate reconciliation categories and income taxes paid by jurisdiction. The amendments are effective for the Company’s annual periods beginning June 1, 2025, with early adoption permitted, and should be applied either prospectively or retrospectively. The Company is currently evaluating the ASU to determine its impact on the Company’s disclosures.