Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Aggregate depreciation, depletion and amortization expense in the current period for the cost of tangible assets, intangible assets, or depleting assets directly related to goods produced and sold during the reporting period.

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Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

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The cash outflow for purchases of and capital improvements on property, plant and equipment (capital expenditures), software, and other intangible assets.

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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014 segment	Dec. 31, 2013	Dec. 31, 2012
Business Segments
Number of business segments									2us-gaap_NumberOfOperatingSegments
Business segments
Revenues	$ 35,401us-gaap_SalesRevenueNet	$ 39,073us-gaap_SalesRevenueNet	$ 38,676us-gaap_SalesRevenueNet	$ 36,691us-gaap_SalesRevenueNet	$ 30,109us-gaap_SalesRevenueNet	$ 36,899us-gaap_SalesRevenueNet	$ 35,172us-gaap_SalesRevenueNet	$ 31,585us-gaap_SalesRevenueNet	$ 149,841us-gaap_SalesRevenueNet	$ 133,765us-gaap_SalesRevenueNet	$ 138,525us-gaap_SalesRevenueNet
Depreciation, depletion and amortization									14,706	14,291	14,850
Gross profit	7,893us-gaap_GrossProfit	9,883us-gaap_GrossProfit	10,423us-gaap_GrossProfit	8,592us-gaap_GrossProfit	6,435us-gaap_GrossProfit	9,110us-gaap_GrossProfit	8,964us-gaap_GrossProfit	6,291us-gaap_GrossProfit	36,791us-gaap_GrossProfit	30,800us-gaap_GrossProfit	33,438us-gaap_GrossProfit
Identifiable assets, at year end	200,420us-gaap_Assets				187,526us-gaap_Assets				200,420us-gaap_Assets	187,526us-gaap_Assets	174,246us-gaap_Assets
Capital expenditures									15,377	8,921	8,292
Lime and limestone operations
Business segments
Revenues									144,567	128,003	131,404
Depreciation, depletion and amortization									13,811	13,336	13,559
Gross profit									33,958	27,913	29,499
Identifiable assets, at year end	128,961				124,839				128,961	124,839	130,059
Capital expenditures									15,352	8,863	8,211
Natural gas interests
Business segments
Revenues									5,274	5,762	7,121
Depreciation, depletion and amortization									895	955	1,291
Gross profit									2,833	2,887	3,939
Identifiable assets, at year end	9,762				10,910				9,762	10,910	11,943
Capital expenditures									25	58	81
Unallocated corporate assets and cash items
Business segments
Identifiable assets, at year end	$ 61,697				$ 51,777				$ 61,697	$ 51,777	$ 32,244