Asset Retirement Obligation (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Asset Retirement Obligation [Line Items]
Asset Retirement Obligation, Beginning Balance	$ 1,780,000us-gaap_AssetRetirementObligation	$ 2,099,000us-gaap_AssetRetirementObligation
Accretion expense	114,000	120,000	132,000
Liabilities incurred	46,000	26,000
Liabilities settled	(70,000)	(417,000)
Revisions in estimated liabilities	138,000	(48,000)
Asset Retirement Obligation, Ending Balance	2,008,000us-gaap_AssetRetirementObligation	1,780,000us-gaap_AssetRetirementObligation	2,099,000us-gaap_AssetRetirementObligation
Decrease in asset reitrement obligation	46,000	26,000	92,000
Tennessee [Member]
Asset Retirement Obligation [Line Items]
Decrease in asset reitrement obligation		$ 348,000

Asset Retirement Obligation Liabilities Settled, Net Of Properties Sold

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- Definition

The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Asset Retirement Obligation

-URI http://asc.fasb.org/extlink&oid=6505190

+ Details

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- Definition

Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6392676&loc=d3e7480-110848

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849

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- Definition

Amount of asset retirement obligations incurred during the period.

+ References

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- Definition

Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

+ References

+ Details

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- Definition

The increase (decrease) during the reporting period in the carrying amount of asset retirement obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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