Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Revenues	$ 181,076	$ 178,007	$ 349,658	$ 351,428
Operating profit (loss)	10,581	5,210	17,949	10,622
Net income (loss)	6,788	3,116	11,766	5,918
Income tax benefit	(2,688)	1,439	(4,358)	460
Operating segments | NACoal
Segment Reporting Information [Line Items]
Revenues	28,100	23,089	56,400	53,376
Operating profit (loss)	10,876	4,823	22,202	14,565
Net income (loss)	8,438	3,324	17,727	11,577
Income tax benefit		2,300		2,300
Other expense		2,200		2,200
Operating segments | HBB
Segment Reporting Information [Line Items]
Revenues	127,574	127,054	241,728	242,794
Operating profit (loss)	5,164	4,696	5,946	4,763
Net income (loss)	3,195	2,934	3,884	2,673
Operating segments | KC
Segment Reporting Information [Line Items]
Revenues	25,868	28,634	52,533	57,017
Operating profit (loss)	(3,008)	(3,011)	(6,287)	(5,901)
Net income (loss)	(1,970)	(1,954)	(4,113)	(3,822)
Operating segments | NACCO and Other
Segment Reporting Information [Line Items]
Operating profit (loss)	(2,459)	(1,297)	(3,979)	(2,738)
Net income (loss)	(2,132)	(1,118)	(3,470)	(2,185)
Eliminations
Segment Reporting Information [Line Items]
Revenues	(466)	(770)	(1,003)	(1,759)
Operating profit (loss)	8	(1)	67	(67)
Net income (loss)	$ (743)	$ (70)	$ (2,262)	$ (2,325)