Property, Plant and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 220,280	$ 207,721
Less allowances for depreciation, depletion and amortization	95,726	87,653
Property, plant and equipment, net	124,554	120,068
Depreciation, depletion and amortization	11,600	10,600
Coal Lands and Real Estate
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	56,716	54,045
Plant and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	163,564	153,676
NACoal | Coal Lands and Real Estate
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	56,247	53,576
NACoal | Plant and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	160,918	151,145
NACCO and Other | Coal Lands and Real Estate
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	469	469
NACCO and Other | Plant and Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, at cost	$ 2,646	$ 2,531