Other Events	12 Months Ended
Other Events	Dec. 31, 2023
Other Events [Abstract]
Other Events	Other Events Coal Deposit Acquisition The Company entered into a definitive agreement dated October 26, 2023, with Stanmore SMC Pty Ltd (Stanmore) to acquire the southern part of Stanmore’s Wards Well tenements (Wards Well area) which are adjacent to the Company’s Centurion Mine, previously known as the North Goonyella Mine, in Queensland, Australia. The acquisition terms include cash consideration of $136 million and a contingent royalty of up to $200 million. The royalty will only be payable once the Company has recovered its investment and development costs of the Wards Well area and if the average sales price achieved exceeds certain thresholds. No royalty is payable if the Company does not commence mining in the Wards Well area. Completion of the transaction is subject to the satisfaction of certain conditions, including regulatory approvals. North Antelope Rochelle Mine Tornado On June 23, 2023, the Company’s North Antelope Rochelle Mine sustained damage from a tornado which led to a temporary suspension of operations. The mine resumed operations on June 25, 2023. During the year ended December 31, 2023, the Company recorded a provision for loss of $12.2 million related to the tornado damage. The combined provision includes $4.0 million for materials and supplies inventories, $1.0 million for buildings and equipment and $7.2 million for incremental repair costs. The Company anticipates that immaterial incremental repair costs will continue to be recorded in early 2024. Shoal Creek Incident On March 29, 2023, the Company’s Shoal Creek Mine experienced a fire involving void fill material utilized to stabilize the roof structure of the mine. On June 20, 2023, the Company announced that the Shoal Creek Mine, in coordination with the Mine Safety and Health Administration, had safely completed localized sealing of the affected area of the mine. In November 2023, longwall coal production commenced in a new area of the mine. During the year ended December 31, 2023, the Company recorded a provision for loss of $28.7 million related to the fire. The provision includes $17.8 million related to longwall development and other costs and $10.9 million for equipment deemed inoperable within the affected area of the mine. In October 2023, the Company filed an insurance claim against applicable insurance policies with combined business interruption and property loss limits of $125 million above a $50 million deductible. Port and Rail Capacity Assignment During the year ended December 31, 2023, the Company entered into two agreements to assign the right to its excess port and rail capacity related to its Centurion Mine to unrelated parties. In the first transaction, the Company assigned its right in exchange for $30.0 million Australian dollars. Half of such amount was received by the Company upon entry into the agreement, and half is payable in June 2024, subject to certain conditions. In connection with the transaction, the Company recorded revenue of $19.2 million during the year ended December 31, 2023 and had a discounted receivable of $9.6 million included in “Accounts receivable, net” as of December 31, 2023. In the second transaction, the Company assigned its right in exchange for $10.0 million Australian dollars, all of which was received as of December 31, 2023. In connection with the transaction, the Company recorded revenue of $6.7 million during the year ended December 31, 2023. Divestitures and Other Transactions During July 2021, the Company executed transactions to sell its closed Millennium and Wilkie Creek Mines, which reduced its closed mine reclamation liabilities and associated costs. The Millennium Mine was sold for minimal cash consideration and the assumption of the majority of the mine’s reclamation liabilities. At December 31, 2023, the Company remains responsible for $4.1 million of reclamation liabilities. The Company recorded a gain of $26.1 million in connection with the sale, which is included within “Net gain on disposals” in the accompanying consolidated statements of operations for the year ended December 31, 2021. The Wilkie Creek Mine was sold for minimal cash consideration and full assumption of the mine’s reclamation liabilities. The Company recorded a gain of $24.6 million in connection with the sale, which is included within “(Loss) income from discontinued operations, net of income taxes” in the accompanying consolidated statements of operations for the year ended December 31, 2021.