Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Oct. 26, 2018
Entity Information [Line Items]
Entity Registrant Name	NACCO INDUSTRIES INC
Entity Central Index Key	0000789933
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Shares Outstanding Class A
Entity Information [Line Items]
Shares Outstanding (in shares)		5,373,804
Shares Outstanding Class B
Entity Information [Line Items]
Shares Outstanding (in shares)		1,568,850