Supplemental Oil and Gas Disclosures (Unaudited) (Narrative) (Details)	Dec. 31, 2025
Extractive Industries [Abstract]
Percentage of proved reserves that are undeveloped (less than)	2.00%

Percentage Of Proved Reserves That Are Undeveloped

No definition available.

Name:	nacco_PercentageOfProvedReservesThatAreUndeveloped
Namespace Prefix:	nacco_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant