Business Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013 segment	Mar. 31, 2012
Business Segments
Number of business segments	2
Business segments
Revenues	$ 31,585	$ 36,028
Depreciation, depletion and amortization	3,653	3,568
Gross profit	6,291	9,203
Capital expenditures	1,519	2,299
Lime and limestone operations
Business segments
Revenues	30,155	33,905
Depreciation, depletion and amortization	3,380	3,254
Gross profit	5,667	7,951
Capital expenditures	1,515	2,286
Natural gas interests
Business segments
Revenues	1,430	2,123
Depreciation, depletion and amortization	273	314
Gross profit	624	1,252
Capital expenditures	$ 4	$ 13

Total expenditures for additions to long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets of the reportable segment; if the amount: (a) is included in the determination of segment assets reviewed by the chief operating decision maker or (b) is otherwise regularly provided to the chief operating decision maker, even if not included in the determination of segment assets.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 28

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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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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- Definition

Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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- Definition

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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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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