Nature of Operations and Basis of Presentation	9 Months Ended
Sep. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations and Basis of Presentation	Nature of Operations and Basis of Presentation Nature of Operations: The accompanying Unaudited Condensed Consolidated Financial Statements include the accounts of NACCO Industries, Inc.^® (the “parent company” or “NACCO”) and its wholly owned subsidiaries (collectively, “NACCO Industries, Inc. and Subsidiaries” or the “Company”). Intercompany accounts and transactions are eliminated in consolidation. NACCO is the public holding company for The North American Coal Corporation^® ("NACoal"). In the first quarter of 2019, the Company changed its segment reporting to three operating segments: Coal Mining, North American Mining (“NAMining”) and Minerals Management. The Company also has unallocated items not directly attributable to a reportable segment. Prior to January 1, 2019, NACoal was the Company’s operating segment. NACCO and Other, which included parent company operations and Bellaire Corporation (“Bellaire”), was the Company’s non-operating segment. Historical financial information for 2018 has been recast to conform to the current presentation. See Note 9 to the Unaudited Condensed Consolidated Financial Statements for further discussion of segment reporting. The Company’s operating segments are further described below: Coal Mining Segment The operating coal mines are: Bisti Fuels LLC (“Bisti”), Caddo Creek Resources Company, LLC (“Caddo Creek”), Camino Real Fuels, LLC (“Camino Real”), The Coteau Properties Company (“Coteau”), Coyote Creek Mining Company, LLC (“Coyote Creek”), Demery Resources Company, LLC (“Demery”), The Falkirk Mining Company (“Falkirk”), Mississippi Lignite Mining Company (“MLMC”) and The Sabine Mining Company (“Sabine”). Liberty Fuels Company, LLC (“Liberty”) ceased all mining and delivery of lignite in 2017 and commenced final mine reclamation in 2018. Centennial Natural Resources (“Centennial”), located in Alabama, ceased coal production at the end of 2015. At all operating coal mines other than MLMC, the Company operates as a contract miner pursuant to a “management fee” contract. Under these long-term contracts, the customer is responsible for funding all mine operating costs and directly or indirectly provides all of the capital required to build and operate the mine. Debt financing provided by or supported by the customers is without recourse to NACCO and NACoal. As a result, these contracts meet the definition of a variable interest entity (“VIE”). NACCO is not the primary beneficiary of the VIE as it does not exercise financial control; therefore, NACCO does not consolidate the results of these operations within its financial statements. Instead, these contracts are accounted for as equity method investments. The income before income taxes is reported as Earnings of unconsolidated operations on the Consolidated Statements of Operations and the Company’s investment is reported on the line Investments in Unconsolidated Subsidiaries in the Consolidated Balance Sheets. The mines that meet the definition of a VIE are referred to collectively as the “Unconsolidated Subsidiaries.” For tax purposes, the Unconsolidated Subsidiaries are included within the NACCO consolidated U.S. tax return; therefore, the income tax expense line on the statements of operations includes taxes related to these entities. All of the Unconsolidated Subsidiaries are accounted for under the equity method. See Note 7 for further discussion. MLMC and Centennial are consolidated operations. The coal reserves at Coteau, Falkirk, Coyote, MLMC and Centennial are owned or controlled by the Company. The coal reserves at all other mines are owned or controlled by the respective mine’s customer. The Unconsolidated Subsidiaries are paid a management fee per ton of coal or heating unit (MMBtu) delivered. Each contract specifies the indices and mechanics by which fees change over time, generally in line with broad measures of U.S. inflation. This contract structure eliminates exposure to spot coal market price fluctuations. NAMining Segment NAMining operates primarily at limestone quarries in Florida, but is focused on expanding outside of Florida and into mining materials other than limestone. NAMining operates under both management fee contracts and contracts that provide for a fixed price per ton. Income before income taxes for NAMining locations are consolidated within NACCO’s consolidated financial statements or are unconsolidated and included on the line Earnings of unconsolidated operations, depending on how each contract is structured. All of the Unconsolidated Subsidiaries are accounted for under the equity method. See Note 7 for further discussion. During the third quarter of 2019, the Company entered into a mining agreement, through a newly-created, wholly owned subsidiary, Sawtooth Mining, LLC, (“Sawtooth”), to serve as exclusive contract miner for the Thacker Pass lithium project in northern Nevada. Thacker Pass is believed to be the largest known lithium deposit in the United States and is 100% owned by Lithium Nevada Corp., a wholly owned subsidiary of Lithium Americas Corp. Sawtooth, which will be reported within the NAMining segment, will design, construct, operate, and maintain the Thacker Pass surface mine, which will supply Lithium Nevada's lithium-bearing claystone ore requirements. The mining agreement provides that Lithium Nevada will reimburse Sawtooth for its operating and mine reclamation costs, and pay Sawtooth a management fee per metric ton of lithium delivered during the 20-year contract term. During the development of the project, Sawtooth will provide Lithium Nevada $3.5 million in cash to assist in project development and provide certain engineering services related primarily to mine design and permitting. As of September 30, 2019, the Company has provided $1.0 million to Lithium Nevada. The $1.0 million is included in the Unaudited Condensed Consolidated Balance Sheet on the line Other non-current assets. Under the terms of the mining agreement, Lithium Nevada will pay Sawtooth a success fee upon achievement of certain engineering, construction and production milestones. After Lithium Nevada secures required permits and financing for the project, Sawtooth intends to acquire up to $50.0 million of mining equipment. The cost of this mining equipment will be reimbursed over a seven-year period from the equipment acquisition date. Lithium Nevada estimates that it will secure all major permits by the end of 2020, commence plant construction in 2021 and commence production of lithium products in 2023. Minerals Management Segment The Minerals Management segment promotes the development of the Company’s oil, gas and coal reserves, generating income primarily from royalty-based lease payments from third parties. The majority of the Company’s existing reserves were acquired as part of its historical coal mining operations. The Minerals Management segment derives income primarily by entering into contracts with third-party operators, granting them the rights to explore, produce and sell natural resources in exchange for royalty payments based on the lessees' sales of natural gas and, to a lesser extent, oil and coal. Specialized employees in the Minerals Management segment also provide surface and mineral acquisition and lease maintenance services related to Company operations. Basis of Presentation: These financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and 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 U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position of the Company at September 30, 2019, the results of its operations, comprehensive income, cash flows and changes in equity for the nine months ended September 30, 2019 and 2018 have been included. These Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2018. The balance sheet at December 31, 2018 has been derived from the audited financial statements at that date but does not include all of the information or notes required by U.S. GAAP for complete financial statements. Certain amounts in prior period Unaudited Condensed Consolidated Financial Statements have been reclassified to conform to the current period's presentation.

Nature of Operations and Basis of Presentation

Nature of Operations: The accompanying Unaudited Condensed Consolidated Financial Statements include the accounts of NACCO Industries, Inc.^® (the “parent company” or “NACCO”) and its wholly owned subsidiaries (collectively, “NACCO Industries, Inc. and Subsidiaries” or the “Company”). Intercompany accounts and transactions are eliminated in consolidation. NACCO is the public holding company for The North American Coal Corporation^® ("NACoal"). In the first quarter of 2019, the Company changed its segment reporting to three operating segments: Coal Mining, North American Mining (“NAMining”) and Minerals Management. The Company also has unallocated items not directly attributable to a reportable segment. Prior to January 1, 2019, NACoal was the Company’s operating segment. NACCO and Other, which included parent company operations and Bellaire Corporation (“Bellaire”), was the Company’s non-operating segment. Historical financial information for 2018 has been recast to conform to the current presentation. See Note 9 to the Unaudited Condensed Consolidated Financial Statements for further discussion of segment reporting.

The Company’s operating segments are further described below:

Coal Mining Segment

The operating coal mines are: Bisti Fuels LLC (“Bisti”), Caddo Creek Resources Company, LLC (“Caddo Creek”), Camino Real Fuels, LLC (“Camino Real”), The Coteau Properties Company (“Coteau”), Coyote Creek Mining Company, LLC (“Coyote Creek”), Demery Resources Company, LLC (“Demery”), The Falkirk Mining Company (“Falkirk”), Mississippi Lignite Mining Company (“MLMC”) and The Sabine Mining Company (“Sabine”). Liberty Fuels Company, LLC (“Liberty”) ceased all mining and delivery of lignite in 2017 and commenced final mine reclamation in 2018. Centennial Natural Resources (“Centennial”), located in Alabama, ceased coal production at the end of 2015.

At all operating coal mines other than MLMC, the Company operates as a contract miner pursuant to a “management fee” contract. Under these long-term contracts, the customer is responsible for funding all mine operating costs and directly or indirectly provides all of the capital required to build and operate the mine. Debt financing provided by or supported by the customers is without recourse to NACCO and NACoal. As a result, these contracts meet the definition of a variable interest entity (“VIE”). NACCO is not the primary beneficiary of the VIE as it does not exercise financial control; therefore, NACCO does not consolidate the results of these operations within its financial statements. Instead, these contracts are accounted for as equity method investments. The income before income taxes is reported as Earnings of unconsolidated operations on the Consolidated Statements of Operations and the Company’s investment is reported on the line Investments in Unconsolidated Subsidiaries in the Consolidated Balance Sheets. The mines that meet the definition of a VIE are referred to collectively as the “Unconsolidated Subsidiaries.” For tax purposes, the Unconsolidated Subsidiaries are included within the NACCO consolidated U.S. tax return; therefore, the income tax expense line on the statements of operations includes taxes related to these entities. All of the Unconsolidated Subsidiaries are accounted for under the equity method. See Note 7 for further discussion. MLMC and Centennial are consolidated operations.

The coal reserves at Coteau, Falkirk, Coyote, MLMC and Centennial are owned or controlled by the Company. The coal reserves at all other mines are owned or controlled by the respective mine’s customer. The Unconsolidated Subsidiaries are paid a management fee per ton of coal or heating unit (MMBtu) delivered. Each contract specifies the indices and mechanics by which fees change over time, generally in line with broad measures of U.S. inflation. This contract structure eliminates exposure to spot coal market price fluctuations.

NAMining Segment

NAMining operates primarily at limestone quarries in Florida, but is focused on expanding outside of Florida and into mining materials other than limestone. NAMining operates under both management fee contracts and contracts that provide for a fixed price per ton. Income before income taxes for NAMining locations are consolidated within NACCO’s consolidated financial statements or are unconsolidated and included on the line Earnings of unconsolidated operations, depending on how each contract is structured. All of the Unconsolidated Subsidiaries are accounted for under the equity method. See Note 7 for further discussion.

During the third quarter of 2019, the Company entered into a mining agreement, through a newly-created, wholly owned subsidiary, Sawtooth Mining, LLC, (“Sawtooth”), to serve as exclusive contract miner for the Thacker Pass lithium project in northern Nevada. Thacker Pass is believed to be the largest known lithium deposit in the United States and is 100% owned by Lithium Nevada Corp., a wholly owned subsidiary of Lithium Americas Corp.

Sawtooth, which will be reported within the NAMining segment, will design, construct, operate, and maintain the Thacker Pass surface mine, which will supply Lithium Nevada's lithium-bearing claystone ore requirements. The mining agreement provides that Lithium Nevada will reimburse Sawtooth for its operating and mine reclamation costs, and pay Sawtooth a management fee per metric ton of lithium delivered during the 20-year contract term. During the development of the project, Sawtooth will provide Lithium Nevada $3.5 million in cash to assist in project development and provide certain engineering services related primarily to mine design and permitting. As of September 30, 2019, the Company has provided $1.0 million to Lithium Nevada. The $1.0 million is included in the Unaudited Condensed Consolidated Balance Sheet on the line Other non-current assets. Under the terms of the mining agreement, Lithium Nevada will pay Sawtooth a success fee upon achievement of certain engineering, construction and production milestones. After Lithium Nevada secures required permits and financing for the project, Sawtooth intends to acquire up to $50.0 million of mining equipment. The cost of this mining equipment will be reimbursed over a seven-year period from the equipment acquisition date. Lithium Nevada estimates that it will secure all major permits by the end of 2020, commence plant construction in 2021 and commence production of lithium products in 2023.

Minerals Management Segment

The Minerals Management segment promotes the development of the Company’s oil, gas and coal reserves, generating income primarily from royalty-based lease payments from third parties. The majority of the Company’s existing reserves were acquired as part of its historical coal mining operations. The Minerals Management segment derives income primarily by entering into contracts with third-party operators, granting them the rights to explore, produce and sell natural resources in exchange for royalty payments based on the lessees' sales of natural gas and, to a lesser extent, oil and coal. Specialized employees in the Minerals Management segment also provide surface and mineral acquisition and lease maintenance services related to Company operations.

Basis of Presentation: These financial statements have been prepared in accordance with U.S. generally accepted accounting principles ("U.S. GAAP") for interim financial information and 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 U.S. GAAP for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position of the Company at September 30, 2019, the results of its operations, comprehensive income, cash flows and changes in equity for the nine months ended September 30, 2019 and 2018 have been included. These Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company's Annual Report on Form 10-K for the year ended December 31, 2018.

The balance sheet at December 31, 2018 has been derived from the audited financial statements at that date but does not include all of the information or notes required by U.S. GAAP for complete financial statements.

Certain amounts in prior period Unaudited Condensed Consolidated Financial Statements have been reclassified to conform to the current period's presentation.