2.4.0.8031 - Disclosure - Property and Equipment (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$Context_As_Of__30-Jun-2013http://www.sec.gov/CIK0000086264instant2013-06-30T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$Context_As_Of__31-Dec-2012http://www.sec.gov/CIK0000086264instant2012-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 5us-gaap_OilAndGasPropertyAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Oil and gas properties2false 6crbo_OilAndGasPropertyFullCostMethodAccumulatedDepreciationDepletionAmortizationAndImpairmentcrbo_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse-60190000-60190USD$falsetruefalse2truefalsefalse-58946000-58946USD$falsetruefalsexbrli:monetaryItemTypemonetaryRepresents the accumulated depreciation, depletion, amortization and impairment of oil and gas properties carried under the full cost method.No definition available.false2Accumulated depreciation, depletion, amortization and impairment3false 6us-gaap_OilAndGasPropertyFullCostMethodNetus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse3604600036046USD$falsefalsefalse2truefalsefalse3331200033312USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOil and gas properties, net of depletion, carried under the full cost method.No definition available.false2Net oil and gas properties4false 5crbo_FurnitureAndFixturesComputerHardwareAndSoftwareAndOtherEquipmentcrbo_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse887000887USD$falsefalsefalse2truefalsefalse782000782USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThis element represents capitalized assets of gross value of furniture and fixtures, computer hardware and software, and other equipment.No definition available.false2Furniture and fixtures, computer hardware and software, and other equipment5false 5us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipmentus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-598000-598USD$falsefalsefalse2truefalsefalse-540000-540USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.14) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 14 -Article 5 false2Accumulated depreciation and amortization6false 5crbo_OtherPropertyAndEquipmentNetcrbo_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalsetotalLabel1truefalsefalse289000289USD$falsefalsefalse2truefalsefalse242000242USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThis element represents capitalized assets of vehicles, furniture and fixtures, computer hardware and software and other equipment net of accumulated depreciation.No definition available.true2Net other property and equipment7false 5us-gaap_PropertyPlantAndEquipmentNetus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse3633500036335USD$falsefalsefalse2truefalsefalse3355400033554USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.13) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph a -Article 5 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 8 -Article 7 false2Total net property and equipment8false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3false USDtruefalse$Context_As_Of__30-Jun-2013_PropertyPlantAndEquipmentByTypeAxis_ProvedOilAndGasPropertiesMemberhttp://www.sec.gov/CIK0000086264instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseProved oil and gas properties [Member]us-gaap_PropertyPlantAndEquipmentByTypeAxisxbrldihttp://xbrl.org/2006/xbrldicrbo_ProvedOilAndGasPropertiesMemberus-gaap_PropertyPlantAndEquipmentByTypeAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Proved oil and gas properties [Member]9true 5us-gaap_OilAndGasPropertyAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Oil and gas properties10false 6us-gaap_OilAndGasPropertyFullCostMethodGrossus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse9449300094493USD$falsefalsefalse2truefalsefalse9113200091132USD$falsefalsefalsexbrli:monetaryItemTypemonetaryOil and gas properties, gross, carried under the full cost method.No definition available.false2Oil and gas properties, gross11false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse5false USDtruefalse$Context_As_Of__30-Jun-2013_PropertyPlantAndEquipmentByTypeAxis_UnprovedPropertiesNotSubjectToDepletionMemberhttp://www.sec.gov/CIK0000086264instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseUnproved properties not subject to depletion [Member]us-gaap_PropertyPlantAndEquipmentByTypeAxisxbrldihttp://xbrl.org/2006/xbrldicrbo_UnprovedPropertiesNotSubjectToDepletionMemberus-gaap_PropertyPlantAndEquipmentByTypeAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Unproved properties not subject to depletion [Member]12true 5us-gaap_OilAndGasPropertyAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Oil and gas properties13false 6us-gaap_OilAndGasPropertyFullCostMethodGrossus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse17430001743USD$falsetruefalse2truefalsefalse11260001126USD$falsetruefalsexbrli:monetaryItemTypemonetaryOil and gas properties, gross, carried under the full cost method.No definition available.false2Oil and gas properties, grossfalseProperty and Equipment (Details) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.cng.com/role/PropertyandEquipmentDetails213