Organization (Details)	9 Months Ended
Sep. 30, 2016 a segment
Organization
Number of business segments \| segment	2
O & G Lease
Organization
Area of land (in acres)	3,800
U.S. Lime O & G \| O & G Lease
Organization
Percentage of non-operating working interest	20.00%
Overall average revenue interest (as a percent)	34.70%
Number of wells	33
U.S. Lime O & G \| O & G Lease \| Minimum
Organization
Percentage of royalty interest	15.40%
U.S. Lime O & G \| O & G Lease \| Maximum
Organization
Percentage of royalty interest	20.00%
U.S. Lime O & G \| Drillsite Agreement
Organization
Percentage of royalty interest	3.00%
Percentage of non-operating working interest	12.50%
Overall average revenue interest (as a percent)	12.40%
Number of wells	6
Area of land under a lease (in acres)	538

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.

No definition available.

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration