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Derivative Instruments Derivative instruments (Details) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2015 USD ($) bbl MMBTU | Dec. 31, 2014 bbl MMBTU | Mar. 31, 2013 USD ($)
Derivative instruments [Line Items] |  |  |
Amount of unrealized gain (loss) on hedge at de-designation date to be reclassified into AOCI |  |  | $ 1,800,000
Cash flow hedge gain (loss) to be reclassified within twelve months from AOCI into earnings | $ (400,000) |  |
Oil swap and or collar [Member] |  |  |
Derivative instruments [Line Items] |  |  |
Derivative, nonmonetary notional amount | bbl | 0 | 270,000 |
Natural gas swap or and collar [Member] |  |  |
Derivative instruments [Line Items] |  |  |
Derivative, nonmonetary notional amount | MMBTU | 0 | 5,000,000 |

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- Definition Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
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- Definition Amount of unrealized gain (loss) on hedge at de-designation date to be reclassified into accumulated other comprehensive income over time. + References No definition available. + Details
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- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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