Business Segments (Details) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) segment	Sep. 30, 2018 USD ($)
Business segments
Number of business segments \| segment			2
Revenues	$ 43,559	$ 35,272	$ 120,312	$ 109,801
Depreciation, depletion and amortization	4,189	4,389	12,482	12,854
Gross profit	13,483	7,196	31,903	23,870
Capital expenditures	8,063	12,309	20,423	31,687
Lime and limestone operations
Business segments
Depreciation, depletion and amortization	4,056	4,234	12,074	12,375
Gross profit	13,477	6,992	31,853	23,112
Capital expenditures	8,063	12,309	20,423	31,687
Natural gas interests
Business segments
Depreciation, depletion and amortization	133	155	408	479
Gross profit	6	204	50	758
Lime and limestone operations
Business segments
Revenues	43,265	34,713	119,311	107,984
Lime and limestone operations \| Lime and limestone operations
Business segments
Revenues	43,265	34,713	119,311	107,984
Natural gas interests
Business segments
Revenues	294	559	1,001	1,817
Natural gas interests \| Natural gas interests
Business segments
Revenues	$ 294	$ 559	$ 1,001	$ 1,817

Amount of expense for allocation of cost of tangible and intangible assets over their useful lives, and reduction in quantity of natural resource due to consumption directly used in production of good and rendering of service.

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-Name Accounting Standards Codification
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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