Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 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 Filer Category	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 145,248,626
Shares Outstanding Class A
Entity Information [Line Items]
Shares Outstanding		5,428,269
Shares Outstanding Class B
Entity Information [Line Items]
Shares Outstanding		1,568,810