Summary of Significant Accounting Policies	12 Months Ended
Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual amounts could differ from these estimates. Revenue Recognition The Company sells coke as well as steam and electricity and also provides mixing and/or handling services of coal and other aggregates. The Company also receives fees for operating the cokemaking plant in Brazil and for the licensing of its proprietary technology for use at this facility as well as reimbursement of substantially all of its operating costs. See Note 18. Cash Equivalents The Company considers all highly liquid investments with a remaining maturity of three months or less at the time of purchase to be cash equivalents. These cash equivalents consist principally of money market funds. Inventories Inventories are valued at the lower of cost or net realizable value. Cost is determined using the first-in, first-out method, except for the Company’s materials and supplies inventory, which are determined using the average-cost method. The Company primarily utilizes the contracted sales prices under its coke sales contracts to record lower of cost or net realizable value inventory adjustments. See Note 5. Properties, Plants and Equipment Plants and equipment are depreciated on a straight-line basis over their estimated useful lives. Coke and energy plant, machinery and equipment are generally depreciated over 25 to 30 years. Logistics plant and equipment are generally depreciated over 15 to 35 years. Depreciation and amortization is excluded from cost of products sold and operating expenses and is presented separately on the Consolidated Statements of Income. Gains and losses on the disposal or retirement of fixed assets are reflected in earnings when the assets are sold or retired. Amounts incurred that extend an asset’s useful life, increase its productivity or add production capacity are capitalized. Additionally, the Company generally capitalizes interest on capital projects with an expected construction period of one year or longer. The Company accounts for changes in useful lives, when appropriate, as a change in estimate, with prospective application only. Direct costs, such as outside labor, materials, internal payroll and benefits costs incurred during capital projects are capitalized; indirect costs are not capitalized. Normal repairs and maintenance costs are expensed as incurred. See Note 6. Intangible Assets Intangible assets are primarily comprised of permits. Intangible assets are amortized over their useful lives in a manner that reflects the pattern in which the economic benefit of the intangible asset is consumed. Intangible assets are assessed for impairment when a triggering event occurs. See Note 7. Impairment of Long-Lived Assets Long-lived assets, which includes intangible assets and properties, plants and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. A long-lived asset, or group of assets, is considered to be impaired when the undiscounted net cash flows expected to be generated by the asset are less than its carrying amount. Such estimated future cash flows are highly subjective and are based on numerous assumptions about future operations and market conditions. The impairment recognized is the amount by which the carrying amount exceeds the fair market value of the impaired asset, or group of assets. It is also difficult to precisely estimate fair market value because quoted market prices for our long-lived assets may not be readily available. Therefore, fair market value is generally based on the present values of estimated future cash flows using discount rates commensurate with the risks associated with the assets being reviewed for impairment. See Note 7. Income Taxes Income tax expense (benefit) is determined by applying the provisions of federal and state tax laws to taxable income (loss) during the period. We do business in a number of states with differing laws concerning how income subject to each state's tax structure is measured. These laws, as well as changes in tax legislation, impact what effective tax rate is applied to income generated in each state, and the Company makes estimates of how income will be apportioned among various states based on these factors. Deferred tax asset and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those differences are projected to be recovered or settled. The Company recognizes uncertain tax positions in its financial statements when minimum recognition threshold and measurement attributes are met in accordance with current accounting guidance. See Note 4. Black Lung Benefit Liabilities The Company has obligations related to coal workers’ pneumoconiosis, or black lung, benefits of certain of our former coal miners and their dependents. We adjust our liability each year based upon actuarial calculations of our expected future payments for these benefits, including a provision for incurred but not reported losses. Adjustments are recognized in the period the adjustment occurs as a component of selling, general and administrative expense on the Consolidated Statements of Income. See Note 12. Postretirement Benefit Plan Liabilities The postretirement benefit plans, which are frozen, are unfunded and the accumulated postretirement benefit obligation is fully recognized on the Consolidated Balance Sheets. Actuarial gains (losses) and prior service costs (benefits) which have not yet been recognized in net income are recognized as a credit (charge) to accumulated other comprehensive income (loss). The credit (charge) to accumulated other comprehensive income (loss), which is reflected net of related tax effects, is subsequently recognized in net income when amortized as a component of postretirement benefit plans expense included in interest expense, net on the Consolidated Statements of Income. See Note 9. Asset Retirement Obligations The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The associated asset retirement costs are capitalized as part of the carrying amount of the asset and depreciated over its remaining estimated useful life. When the assumptions used to estimate a recorded asset retirement obligation change, a revision is recorded to both the asset retirement obligation and the asset retirement cost capitalized to the extent remaining useful life exists. The Company’s asset retirement obligations primarily relate to costs associated with restoring land to its original state. See Note 8. Leases We determine if an arrangement contains a lease at inception. We recognize right-of-use assets and lease liabilities associated with leases based on the present value of the future minimum lease payments over the lease term at the commencement date. Our leases do not provide an implicit rate of return, therefore, we use our incremental borrowing rate at the inception of the lease to calculate the present value of lease payments. Our incremental borrowing rate is determined through market sources for secured borrowings and approximates the interest rate at which we could borrow on a collateralized basis with similar terms and payments in similar economic environments. Lease terms reflect options to extend or terminate the lease when it is reasonably certain that the option will be exercised. The Company has elected to apply the short-term lease exception for all asset classes, therefore, excluding all leases with a term of less than 12 months from the balance sheet, and will recognize the lease payments in the period they are incurred. Additionally, the Company accounts for lease and non-lease components of an arrangement, such as assets and services, as a single lease component for all asset classes on existing leases. See Note 13. Shipping and Handling Costs Shipping and handling costs are included in cost of products sold and operating expenses on the Consolidated Statements of Income and are generally passed through to our customers. The Company has elected the practical expedient under Accounting Standards Codification ("ASC") 606, "Revenue from Contracts with Customers," to account for shipping and handling activities as a promise to fulfill the transfer of coke. See Note 18. Share-Based Compensation We measure the cost of employee services in exchange for equity instrument awards and cash awards based on the grant-date fair value of the award. Cash awards and the performance metrics of equity awards are remeasured on a quarterly basis. The market metrics of equity awards are not remeasured. The total cost is recognized over the requisite service period. Award forfeitures are accounted for as they occur. The costs of equity awards and cash awards are recorded to additional paid-in capital and accrued liabilities, respectively, on the Consolidated Balance Sheets. See Note 15. Fair Value Measurements The Company determines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As required, the Company utilizes valuation techniques that maximize the use of observable inputs (levels 1 and 2) and minimize the use of unobservable inputs (level 3) within the fair value hierarchy included in current accounting guidance. Assets and liabilities are classified within the fair value hierarchy based on the lowest level (least observable) input that is significant to the measurement in its entirety. See Note 17. Currency Translation The functional currency of the Company’s Brazilian operations is the Brazilian real. The Company’s Brazil operations translate its assets and liabilities into U.S. dollars at the current exchange rates in effect at the end of the fiscal period. The gains or losses that result from this process are shown as cumulative translation adjustments within accumulated other comprehensive loss in the Consolidated Balance Sheets. The revenue and expense accounts of foreign operations are translated into U.S. dollars at the average exchange rates during the period. Recent Accounting Pronouncements In December, 2022 the Financial Accounting Standards Board ("FASB") issued ASU 2022-06 Reference Rate Reform (Topic 848):Deferral of the Sunset Date of Topic 848 as an amendment to previously issued ASU 2020-04 Reference Rate Reform (Topic 848):Facilitation of the Effects of Reference Rate Reform on Financial Reporting. These updates help limit the accounting impact from contract modifications due to the transition from LIBOR to alternative reference rates that are completed by December 31, 2024. The Company does not expect the transition from LIBOR to SOFR to have a material impact on the consolidated financial statements and disclosures. Refer to Note 11 for further detail. Labor Concentrations As of December 31, 2022, we have 887 employees in the U.S. Approximately 40 percent of our domestic employees, principally at our cokemaking operations, are represented by the United Steelworkers union under various contracts. Additionally, approximately 3 percent of our domestic employees are represented by the International Union of Operating Engineers. Labor agreements at KRT, Lake Terminal, and Indiana Harbor were renewed in 2022 and will expire on April 30, 2025, June 30, 2025, and September 1, 2026, respectively. As of December 31, 2022,we have 285 employees at the cokemaking facility in Vitória, Brazil, all of whom are represented by a union under a labor agreement. During 2022, the labor agreement at our Vitória, Brazil facility was renewed for an additional year, and it expires on October 31, 2023.

The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual amounts could differ from these estimates.

The Company sells coke as well as steam and electricity and also provides mixing and/or handling services of coal and other aggregates. The Company also receives fees for operating the cokemaking plant in Brazil and for the licensing of its proprietary technology for use at this facility as well as reimbursement of substantially all of its operating costs. See Note 18.

Inventories are valued at the lower of cost or net realizable value. Cost is determined using the first-in, first-out method, except for the Company’s materials and supplies inventory, which are determined using the average-cost method. The Company primarily utilizes the contracted sales prices under its coke sales contracts to record lower of cost or net realizable value inventory adjustments. See Note 5.

Plants and equipment are depreciated on a straight-line basis over their estimated useful lives. Coke and energy plant, machinery and equipment are generally depreciated over 25 to 30 years. Logistics plant and equipment are generally depreciated over 15 to 35 years. Depreciation and amortization is excluded from cost of products sold and operating

expenses and is presented separately on the Consolidated Statements of Income. Gains and losses on the disposal or retirement of fixed assets are reflected in earnings when the assets are sold or retired. Amounts incurred that extend an asset’s useful life, increase its productivity or add production capacity are capitalized. Additionally, the Company generally capitalizes interest on capital projects with an expected construction period of one year or longer. The Company accounts for changes in useful lives, when appropriate, as a change in estimate, with prospective application only. Direct costs, such as outside labor, materials, internal payroll and benefits costs incurred during capital projects are capitalized; indirect costs are not capitalized. Normal repairs and maintenance costs are expensed as incurred. See Note 6.

Intangible assets are primarily comprised of permits. Intangible assets are amortized over their useful lives in a manner that reflects the pattern in which the economic benefit of the intangible asset is consumed. Intangible assets are assessed for impairment when a triggering event occurs. See Note 7.

Long-lived assets, which includes intangible assets and properties, plants and equipment, are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. A long-lived asset, or group of assets, is considered to be impaired when the undiscounted net cash flows expected to be generated by the asset are less than its carrying amount. Such estimated future cash flows are highly subjective and are based on numerous assumptions about future operations and market conditions. The impairment recognized is the amount by which the carrying amount exceeds the fair market value of the impaired asset, or group of assets. It is also difficult to precisely estimate fair market value because quoted market prices for our long-lived assets may not be readily available. Therefore, fair market value is generally based on the present values of estimated future cash flows using discount rates commensurate with the risks associated with the assets being reviewed for impairment. See Note 7.

Income tax expense (benefit) is determined by applying the provisions of federal and state tax laws to taxable income (loss) during the period. We do business in a number of states with differing laws concerning how income subject to each state's tax structure is measured. These laws, as well as changes in tax legislation, impact what effective tax rate is applied to income generated in each state, and the Company makes estimates of how income will be apportioned among various states based on these factors. Deferred tax asset and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those differences are projected to be recovered or settled. The Company recognizes uncertain tax positions in its financial statements when minimum recognition threshold and measurement attributes are met in accordance with current accounting guidance. See Note 4.

The Company has obligations related to coal workers’ pneumoconiosis, or black lung, benefits of certain of our former coal miners and their dependents. We adjust our liability each year based upon actuarial calculations of our expected future payments for these benefits, including a provision for incurred but not reported losses. Adjustments are recognized in the period the adjustment occurs as a component of selling, general and administrative expense on the Consolidated Statements of Income. See Note 12.

The postretirement benefit plans, which are frozen, are unfunded and the accumulated postretirement benefit obligation is fully recognized on the Consolidated Balance Sheets. Actuarial gains (losses) and prior service costs (benefits) which have not yet been recognized in net income are recognized as a credit (charge) to accumulated other comprehensive income (loss). The credit (charge) to accumulated other comprehensive income (loss), which is reflected net of related tax effects, is subsequently recognized in net income when amortized as a component of postretirement benefit plans expense included in interest expense, net on the Consolidated Statements of Income. See Note 9.

The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The associated asset retirement costs are capitalized as part of the carrying amount of the asset and depreciated over its remaining estimated useful life. When the assumptions used to estimate a recorded asset retirement obligation change, a revision is recorded to both the asset retirement obligation and the asset retirement cost capitalized to the extent remaining useful life exists. The Company’s asset retirement obligations primarily relate to costs associated with restoring land to its original state. See Note 8.

We determine if an arrangement contains a lease at inception. We recognize right-of-use assets and lease liabilities associated with leases based on the present value of the future minimum lease payments over the lease term at the commencement date. Our leases do not provide an implicit rate of return, therefore, we use our incremental borrowing rate at the inception of the lease to calculate the present value of lease payments. Our incremental borrowing rate is determined through market sources for secured borrowings and approximates the interest rate at which we could borrow on a collateralized basis with similar terms and payments in similar economic environments. Lease terms reflect options to extend or terminate the lease when it is reasonably certain that the option will be exercised. The Company has elected to apply the short-term lease exception for all asset classes, therefore, excluding all leases with a term of less than 12 months from the balance sheet, and will recognize the lease payments in the period they are incurred. Additionally, the Company accounts for lease and non-lease components of an arrangement, such as assets and services, as a single lease component for all asset classes on existing leases. See Note 13.

Shipping and handling costs are included in cost of products sold and operating expenses on the Consolidated Statements of Income and are generally passed through to our customers. The Company has elected the practical expedient under Accounting Standards Codification ("ASC") 606, "Revenue from Contracts with Customers," to account for shipping and handling activities as a promise to fulfill the transfer of coke. See Note 18.

We measure the cost of employee services in exchange for equity instrument awards and cash awards based on the grant-date fair value of the award. Cash awards and the performance metrics of equity awards are remeasured on a quarterly basis. The market metrics of equity awards are not remeasured. The total cost is recognized over the requisite service period. Award forfeitures are accounted for as they occur. The costs of equity awards and cash awards are recorded to additional paid-in capital and accrued liabilities, respectively, on the Consolidated Balance Sheets. See Note 15.

The Company determines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. As required, the Company utilizes valuation techniques that maximize the use of observable inputs (levels 1 and 2) and minimize the use of unobservable inputs (level 3) within the fair value hierarchy included in current accounting guidance. Assets and liabilities are classified within the fair value hierarchy based on the lowest level (least observable) input that is significant to the measurement in its entirety. See Note 17.

The functional currency of the Company’s Brazilian operations is the Brazilian real. The Company’s Brazil operations translate its assets and liabilities into U.S. dollars at the current exchange rates in effect at the end of the fiscal period. The gains or losses that result from this process are shown as cumulative translation adjustments within accumulated other comprehensive loss in the Consolidated Balance Sheets. The revenue and expense accounts of foreign operations are translated into U.S. dollars at the average exchange rates during the period.

In December, 2022 the Financial Accounting Standards Board ("FASB") issued ASU 2022-06 Reference Rate Reform (Topic 848):Deferral of the Sunset Date of Topic 848 as an amendment to previously issued ASU 2020-04 Reference Rate Reform (Topic 848):Facilitation of the Effects of Reference Rate Reform on Financial Reporting. These updates help limit the accounting impact from contract modifications due to the transition from LIBOR to alternative reference rates that are completed by December 31, 2024. The Company does not expect the transition from LIBOR to SOFR to have a material impact on the consolidated financial statements and disclosures. Refer to Note 11 for further detail.

As of December 31, 2022, we have 887 employees in the U.S. Approximately 40 percent of our domestic employees, principally at our cokemaking operations, are represented by the United Steelworkers union under various contracts. Additionally, approximately 3 percent of our domestic employees are represented by the International Union of Operating Engineers. Labor agreements at KRT, Lake Terminal, and Indiana Harbor were renewed in 2022 and will expire on April 30, 2025, June 30, 2025, and September 1, 2026, respectively.