Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 193,734	$ 177,413
Operating profit (loss)	3,241	(585)
Net income (loss)	1,027	(1,524)
Operating segments | NACoal
Segment Reporting Information [Line Items]
Revenues	41,319	39,872
Operating profit (loss)	5,207	6,653
Net income (loss)	4,547	5,705
Operating segments | HBB
Segment Reporting Information [Line Items]
Revenues	123,293	101,325
Operating profit (loss)	2,188	937
Net income (loss)	618	350
Operating segments | KC
Segment Reporting Information [Line Items]
Revenues	29,967	36,876
Operating profit (loss)	(3,045)	(6,514)
Net income (loss)	(1,893)	(4,033)
Operating segments | NACCO and Other
Segment Reporting Information [Line Items]
Operating profit (loss)	(1,289)	(1,352)
Net income (loss)	(1,239)	(1,197)
Eliminations
Segment Reporting Information [Line Items]
Revenues	(845)	(660)
Operating profit (loss)	180	(309)
Net income (loss)	$ (1,006)	$ (2,349)