2.4.0.8022 - Disclosure - Summary of Significant Accounting Policies (Tables)truefalsefalse1false falsefalseContext_6ME__30-Jun-2013http://www.sec.gov/CIK0000086264duration2013-01-01T00:00:002013-06-30T00:00:001true 1us-gaap_AccountingPoliciesAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Summary of Significant Accounting Policies [Abstract]2false 2us-gaap_ScheduleOfChangeInAssetRetirementObligationTableTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00<div align="right"> <table style="width: 100%; font-family: times new roman; font-size: 10pt;" cellspacing="0" cellpadding="0"> <tr> <td style="padding-bottom: 2px;" valign="bottom">  </td> <td style="padding-bottom: 2px;" valign="bottom"> </td> <td style="border-bottom: black 2px solid;" valign="bottom" colspan="6"> <div align="center" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;">Six Months Ended June 30,</div> </td> <td style="text-align: left; padding-bottom: 2px;" valign="bottom" nowrap="nowrap"> </td> </tr> <tr> <td style="padding-bottom: 2px;" valign="bottom"> <div align="justify" style="text-indent: 0pt; display: block; margin-left: 9pt; margin-right: 0pt;">(in thousands)</div> </td> <td style="padding-bottom: 2px;" valign="bottom"> </td> <td style="border-bottom: black 2px solid;" valign="bottom" colspan="2"> <div align="center" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;">2013</div> </td> <td style="text-align: left; padding-bottom: 2px;" valign="bottom" nowrap="nowrap"> </td> <td style="padding-bottom: 2px;" valign="bottom"> </td> <td style="border-bottom: black 2px solid;" valign="bottom" colspan="2"> <div align="center" style="text-indent: 0pt; display: block; margin-left: 0pt; margin-right: 0pt;">2012</div> </td> <td style="text-align: left; padding-bottom: 2px;" valign="bottom" nowrap="nowrap"> </td> </tr> <tr bgcolor="#cceeff"> <td valign="bottom" width="76%"> <div align="justify" style="text-indent: 0pt; display: block; margin-left: 9pt; margin-right: 0pt;">Balance at beginning of period</div> </td> <td align="right" valign="bottom" width="1%"> </td> <td style="text-align: left;" valign="bottom" width="1%">$</td> <td style="text-align: right;" valign="bottom" width="9%">2,321</td> <td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"> </td> <td align="right" valign="bottom" width="1%"> </td> <td style="text-align: left;" valign="bottom" width="1%">$</td> <td style="text-align: right;" valign="bottom" width="9%">2,149</td> <td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"> </td> </tr> <tr bgcolor="white"> <td valign="bottom" width="76%"> <div align="justify" style="text-indent: 0pt; display: block; margin-left: 9pt; margin-right: 0pt;">Accretion expense</div> </td> <td align="right" valign="bottom" width="1%"> </td> <td style="text-align: left;" valign="bottom" width="1%"> </td> <td style="text-align: right;" valign="bottom" width="9%">68</td> <td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"> </td> <td align="right" valign="bottom" width="1%"> </td> <td style="text-align: left;" valign="bottom" width="1%"> </td> <td style="text-align: right;" valign="bottom" width="9%">52</td> <td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"> </td> </tr> <tr bgcolor="#cceeff"> <td style="padding-bottom: 2px;" valign="bottom" width="76%"> <div align="justify" style="text-indent: 0pt; display: block; margin-left: 9pt; margin-right: 0pt;">Additions during period</div> </td> <td align="right" style="padding-bottom: 2px;" valign="bottom" width="1%"> </td> <td style="border-bottom: black 2px solid; text-align: left;" valign="bottom" width="1%"> </td> <td style="border-bottom: black 2px solid; text-align: right;" valign="bottom" width="9%">151</td> <td style="text-align: left; padding-bottom: 2px;" valign="bottom" width="1%" nowrap="nowrap"> </td> <td align="right" style="padding-bottom: 2px;" valign="bottom" width="1%"> </td> <td style="border-bottom: black 2px solid; text-align: left;" valign="bottom" width="1%"> </td> <td style="border-bottom: black 2px solid; text-align: right;" valign="bottom" width="9%">10</td> <td style="text-align: left; padding-bottom: 2px;" valign="bottom" width="1%" nowrap="nowrap"> </td> </tr> <tr bgcolor="white"> <td valign="bottom" width="76%">  </td> <td valign="bottom" width="1%"> </td> <td style="text-align: left;" valign="bottom" width="1%"> </td> <td style="text-align: right;" valign="bottom" width="9%"> </td> <td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"> </td> <td valign="bottom" width="1%"> </td> <td style="text-align: left;" valign="bottom" width="1%"> </td> <td style="text-align: right;" valign="bottom" width="9%"> </td> <td style="text-align: left;" valign="bottom" width="1%" nowrap="nowrap"> </td> </tr> <tr bgcolor="#cceeff"> <td style="padding-bottom: 4px;" valign="bottom" width="76%"> <div align="justify" style="text-indent: 0pt; display: block; margin-left: 9pt; margin-right: 0pt;">Balance at end of period</div> </td> <td align="right" style="padding-bottom: 4px;" valign="bottom" width="1%"> </td> <td style="border-bottom: black 4px double; text-align: left;" valign="bottom" width="1%">$</td> <td style="border-bottom: black 4px double; text-align: right;" valign="bottom" width="9%">2,540</td> <td style="text-align: left; padding-bottom: 4px;" valign="bottom" width="1%" nowrap="nowrap"> </td> <td align="right" style="padding-bottom: 4px;" valign="bottom" width="1%"> </td> <td style="border-bottom: black 4px double; text-align: left;" valign="bottom" width="1%">$</td> <td style="border-bottom: black 4px double; text-align: right;" valign="bottom" width="9%">2,211</td> <td style="text-align: left; padding-bottom: 4px;" valign="bottom" width="1%" nowrap="nowrap"> </td> </tr> </table> </div>falsefalsefalsenonnum:textBlockItemTypenaTabular disclosure of the changes in carrying amount of a liability for asset retirement obligations, for changes such as new obligations, changes in estimates of existing obligations, spending on existing obligations, property dispositions, and foreign currency translation.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13201-110859 false0Summary of reconciliation of the AROfalseSummary of Significant Accounting Policies (Tables)UnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.cng.com/role/SummaryofSignificantAccountingPoliciesTables12