Property Plant & Equipment Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Natural Gas Production Per Day	502egas_NaturalGasProductionPerDay	550egas_NaturalGasProductionPerDay	593egas_NaturalGasProductionPerDay
Percentage Of Gas Production As Aggregate Volume Requirements	26.00%	25.00%	19.90%
Property, Plant and Equipment, Net	$ 142,011,085us-gaap_PropertyPlantAndEquipmentNet	$ 124,587,645us-gaap_PropertyPlantAndEquipmentNet
Build-to-suit Lease [Member]
Construction in Progress, Gross	6,500,000
Ewr Subsidiary [Member]
Natural Gas Production Per Day	395	422	461
Percentage Of Gas Production As Aggregate Volume Requirements	20.00%	19.00%	15.50%
Ewd Subsidiary [Member]
Number Of Natural Gas Production Properties Owned	50
Natural Gas Production Per Day	107	129	132
Percentage Of Gas Production As Aggregate Volume Requirements	5.50%	5.80%	4.40%
Percentage Of Ownership Interest In Gathering System	75.00%
Natural Gas [Member]
Net Present Value Of Natural Gas Reserves	2,700,000	2,100,000
Percentage Of Depletion On Wells Per Year	10.00%	10.00%
Proved Developed and Undeveloped Reserves, Net	2.1	2.3
Fair Value Inputs, Discount Rate	10.00%
Property, Plant and Equipment, Net	$ 900,000	$ 1,000,000

Natural gas production per day.

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- Definition

Net present value of natural gas reserves.

+ References

No definition available.

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- Definition

Number of natural gas production properties owned.

+ References

No definition available.

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- Definition

Percentage of depletion on wells per year.

+ References

No definition available.

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- Definition

Percentage of gas production as aggregate volume requirements.

+ References

No definition available.

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- Definition

Percentage of ownership interest in gathering system.

+ References

No definition available.

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- Definition

Amount of structure or a modification to a structure under construction. Includes recently completed structures or modifications to structures that have not been placed into service.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

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- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

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

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

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- Definition

The net quantity of proved reserves as of the balance sheet date. Proved oil reserves are the estimated quantities of crude oil and natural gas liquids which geological and engineering data demonstrate with reasonable certainty to be recoverable.

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