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Summary of Significant Accounting Policies (Asset Retirement Obligation) (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
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Accounting Policies [Abstract] |  |
Retirement obligation | $ 5,231 | $ 4,835
Discount rate | 6.00% | 6.00%
Present value, recorded as a liability | $ 1,184 | $ 1,966
Deferred tax | 0 | 1,352
Regulatory asset | $ 1,184 | $ 3,318

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- Definition Asset Retirement Obligation, Deferred Tax + References No definition available. + Details
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- Definition Asset Retirement Obligation, Discount Rate + References No definition available. + Details
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- Definition Asset Retirement Obligation, Present Value + References No definition available. + Details
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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 + Details
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- Definition Carrying amount of an asset that is legally restricted for purposes of settling an asset retirement obligation. + 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 (b) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
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