Business Segments (Balance Sheets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Total assets	$ 389,552	$ 668,021	$ 655,408
Depreciation, depletion and amortization	12,767	13,050	17,372
Capital expenditures	15,704	10,165	4,444
Operating Segments | NACoal
Segment Reporting Information [Line Items]
Total assets	277,538	287,011	303,138
Depreciation, depletion and amortization	12,444	12,682	17,067
Capital expenditures	15,692	10,109	4,116
NACCO and Other | NACCO and Other
Segment Reporting Information [Line Items]
Total assets	135,434	109,022	64,069
Depreciation, depletion and amortization	323	368	305
Capital expenditures	12	56	328
Eliminations
Segment Reporting Information [Line Items]
Total assets	(23,420)	(39,183)	(21,850)
Discontinued Operations, Disposed of by Means Other than Sale, Spinoff
Segment Reporting Information [Line Items]
Total assets	$ 0	$ 311,171	$ 310,051