Nature of Operations and Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	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 per ton sales price. 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. 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	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 June 30, 2019, the results of its operations, comprehensive income, cash flows and changes in equity for the six months ended June 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.
Accounting Standards Adopted	Accounting Standards Adopted in 2019: NACCO adopted Accounting Standard Update ("ASU") 2016-02, Leases (Topic 842), which is codified in Accounting Standards Codification 842, Leases (“ASC 842”), on January 1, 2019, using the modified retrospective transition method (the "guidance"). The most significant effect to the Unaudited Condensed Consolidated Balance Sheet relates to the recognition of new right-of-use assets (“ROU assets”) and lease liabilities for operating leases of real estate, mining and other equipment that expire at various dates through 2031. The majority of the Company's leases are operating leases. See the table below for further information on the Unaudited Condensed Consolidated Balance Sheet. Many leases include renewal and/or fair value or bargain purchase options, which are not recognized on the Unaudited Condensed Consolidated Balance Sheet. There was no cumulative effect adjustment to the opening balance of retained earnings. The adoption of this guidance did not have a material effect on the Company’s results of operations, cash flows, liquidity or debt-covenant compliance. NACCO did not apply the standard to the comparative periods presented in the year of adoption. The Company elected many of the available practical expedients permitted under the guidance, which among other items, allow the Company to carry forward its historical lease classification and not reassess leases for the definition of a lease under the new standard. The Company also elected the practical expedient to carry forward the historical accounting treatment for existing land easement agreements. Upon the adoption of ASC 842, NACCO did not record a ROU asset and related lease liability for leases with an initial term of 12 months or less.