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Supplemental Oil and Gas Disclosures (Unaudited) (Narrative) (Details) | Dec. 31, 2024
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Extractive Industries [Abstract] |
Percentage of proved reserves that are undeveloped (less than) | 1.00%

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- Definition Percentage Of Proved Reserves That Are Undeveloped + References No definition available. + Details
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Namespace Prefix: | nacco_
Data Type: | dtr-types1:percentItemType
Balance Type: | na
Period Type: | instant

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- References No definition available. + Details
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Namespace Prefix: | srt_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration