Quarterly Results of Operations (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenues	$ 286,519	$ 239,107	$ 196,500	$ 193,734	$ 297,285	$ 221,714	$ 200,370	$ 177,413	$ 915,860	$ 896,782	$ 932,666
Gross profit	63,711	42,215	35,381	38,189	65,835	46,543	36,523	36,171	179,496	185,072	221,291
Earnings of unconsolidated mines	11,569	12,234	12,076	12,553	12,327	12,064	11,567	12,438	48,432	48,396	46,429
Operating profit	21,538	5,760	1,288	3,241	(73,156)	11,323	(3,891)	(585)	31,827	(66,309)	61,336
Income (loss) from continuing operations	$ 18,091	$ 3,141	$ (275)	$ 1,027					21,984	(38,118)	44,450
Net income (loss)					$ (40,669)	$ 7,699	$ (3,624)	$ (1,524)	21,984	(38,118)	44,450
Basic earnings (loss) per share:
Basic earnings per share	$ 2.65	$ 0.45	$ (0.04)	$ 0.14	$ (5.57)	$ 1.02	$ (0.47)	$ (0.19)
Diluted earnings per share	$ 2.63	$ 0.45	$ (0.04)	$ 0.14	$ (5.57)	$ 1.02	$ (0.47)	$ (0.19)
Reed Minerals long-lived asset impairment charge		$ 7,500
Selling, general and administrative expenses | Increase in estimated liability for certain frozen deferred compensation plans
Basic earnings (loss) per share:
Immaterial error correction							$ 1,100
NACoal
Segment Reporting Information [Line Items]
Revenues	$ 26,033	42,704	$ 37,942	$ 41,319	$ 33,210	$ 49,840	49,780	$ 39,872	147,998	172,702	193,651
Gross profit									(10,816)	(3,139)	25,230
Operating profit	(3,058)	(4,010)	2,382	5,207	(100,228)	4,362	183	6,653	521	(89,030)	37,461
Income (loss) from continuing operations	2,218	(5,345)	4,199	4,547	(59,792)	3,185	(75)	5,705	5,619	(50,977)	31,926
HBB
Segment Reporting Information [Line Items]
Revenues	204,895	163,291	129,498	123,293	204,818	135,155	118,385	101,325	620,977	559,683	547,790
Gross profit									123,139	117,570	115,506
Operating profit	18,090	11,643	2,880	2,188	23,053	9,531	2,251	937	34,801	35,772	40,960
Income (loss) from continuing operations	11,135	6,378	1,618	618	15,427	6,008	1,359	350	19,749	23,144	25,093
KC
Segment Reporting Information [Line Items]
Revenues	56,531	34,708	29,782	29,967	61,314	37,551	32,804	36,876	150,988	168,545	196,033
Gross profit									67,000	71,621	80,972
Operating profit	7,025	(843)	(2,972)	(3,045)	5,123	(1,429)	(4,255)	(6,514)	165	(7,075)	(10,903)
Income (loss) from continuing operations	3,870	(550)	(1,847)	(1,893)	3,053	(966)	(2,657)	(4,033)	(420)	(4,603)	(6,884)
NACCO and Other
Segment Reporting Information [Line Items]
Gross profit									(416)	(461)	(469)
Operating profit	(981)	(1,142)	(836)	(1,289)	(1,027)	(1,073)	(2,004)	(1,352)	(4,248)	(5,456)	(6,233)
Income (loss) from continuing operations	(636)	(774)	(697)	(1,239)	(1,568)	(906)	(1,673)	(1,197)	(3,346)	(5,344)	(5,718)
Eliminations
Segment Reporting Information [Line Items]
Revenues	(940)	(1,596)	(722)	(845)	(2,057)	(832)	(599)	(660)	(4,103)	(4,148)	(4,808)
Gross profit									589	(519)	52
Operating profit	462	112	(166)	180	(77)	(68)	(66)	(309)	588	(520)	51
Income (loss) from continuing operations	$ 1,504	$ 3,432	$ (3,548)	$ (1,006)	2,211	$ 378	$ (578)	$ (2,349)	$ 382	$ (338)	$ 33
Reed Minerals | NACoal
Basic earnings (loss) per share:
Reed Minerals long-lived asset impairment charge					$ 105,100