Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 31,200	$ 28,300
Operating profit (loss)	9,721	9,806
NACoal
Segment Reporting Information [Line Items]
Revenues	31,200	28,300
Operating segments | NACoal
Segment Reporting Information [Line Items]
Operating profit (loss)	11,282	11,326
NACCO and Other
Segment Reporting Information [Line Items]
Operating profit (loss)	$ (1,561)	$ (1,520)