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Related Party Transactions (Details) (USD $) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Sep. 28, 2012
Related Party Transaction [Line Items] |  |  |  |
Lease operating expenses | $ 52,191,000 us-gaap_LeaseOperatingExpense | $ 26,703,000 us-gaap_LeaseOperatingExpense | $ 24,308,000 us-gaap_LeaseOperatingExpense |
General and administrative | 38,290,000 us-gaap_GeneralAndAdministrativeExpense | 22,519,000 us-gaap_GeneralAndAdministrativeExpense | 13,808,000 us-gaap_GeneralAndAdministrativeExpense |
Ownership percentage by noncontrolling owners |  |  |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Windsor Niobrara LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Revenue from related parties |  | 900,000 us-gaap_RevenueFromRelatedParties / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_WindsorNiobraraLlcMember |  |
Windsor Ohio LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party |  | (1,600,000)us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_WindsorOhioLlcMember |  |
Revenue from related parties |  | 73,400,000 us-gaap_RevenueFromRelatedParties / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_WindsorOhioLlcMember |  |
Stingray Pressure Pumping LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party |  | 8,300,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayPressurePumpingLlcMember |  |
Oil and natural gas properties | 78,300,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayPressurePumpingLlcMember | 58,300,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayPressurePumpingLlcMember |  |
Ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayPressurePumpingLlcMember |  |  |
Stingray Cementing LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party | 800,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayCementingLlcMember | 1,500,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayCementingLlcMember |  |
Oil and natural gas properties | 6,000,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayCementingLlcMember | 4,000,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayCementingLlcMember |  |
Ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayCementingLlcMember |  |  |
Stingray Energy Services LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party | 6,000,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember | 4,100,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember |  |
Oil and natural gas properties | 24,800,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember | 5,100,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember |  |
Ownership interest | 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember |  |  |
Athena Construction Llc [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party |  | 1,000,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_AthenaConstructionLlcMember |  |
Lease operating expenses |  | 600,000 us-gaap_LeaseOperatingExpense / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_AthenaConstructionLlcMember |  |
Oil and natural gas properties |  | 4,100,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_AthenaConstructionLlcMember |  |
Panther Drilling Systems, LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party | 2,400,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_PantherDrillingSystemsLLCMember | 1,800,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_PantherDrillingSystemsLLCMember |  |
Oil and natural gas properties | 7,600,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_PantherDrillingSystemsLLCMember | 12,600,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_PantherDrillingSystemsLLCMember |  |
Ownership interest | 30.50%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_PantherDrillingSystemsLLCMember |  |  |
Redback Directional Services, LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party | (400,000)us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_RedbackDirectionalServicesLLCMember | 0 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_RedbackDirectionalServicesLLCMember |  |
Oil and natural gas properties | 1,000,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_RedbackDirectionalServicesLLCMember | 100,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_RedbackDirectionalServicesLLCMember |  |
Ownership interest | 30.50%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_RedbackDirectionalServicesLLCMember |  |  |
Muskie Holdings LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party | 28,400,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_MuskieHoldingsLlcMember |  |  |
Oil and natural gas properties | 11,100,000 gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_MuskieHoldingsLlcMember |  |  |
Ownership interest | 30.50%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_MuskieHoldingsLlcMember |  |  |
Caliber Development Company, LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
General and administrative |  | 200,000 us-gaap_GeneralAndAdministrativeExpense / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_CaliberDevelopmentCompanyLlcMember |  |
Executive Officer [Member] | Windsor Niobrara LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_WindsorNiobraraLlcMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Executive Officer [Member] | Windsor Ohio LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_WindsorOhioLlcMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Executive Officer [Member] | Athena Construction Llc [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_AthenaConstructionLlcMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Executive Officer [Member] | Black Fin P Llc [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_BlackFinPLlcMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Executive Officer [Member] | Panther Drilling Systems, LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_PantherDrillingSystemsLLCMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Executive Officer [Member] | Redback Directional Services, LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_RedbackDirectionalServicesLLCMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Executive Officer [Member] | Caliber Development Company, LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership percentage by noncontrolling owners |  | 10.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_CaliberDevelopmentCompanyLlcMember / us-gaap_TitleOfIndividualAxis = us-gaap_ExecutiveOfficerMember |  |
Mammoth Energy Partners LP [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Ownership interest | 30.50%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_MammothEnergyPartnersLPMember |  |  |
Lease Operating Expense [Member] | Stingray Energy Services LLC [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Due from (to) related party | $ 1,300,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_IncomeStatementLocationAxis = gpor_LeaseOperatingExpenseMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember | $ 1,300,000 us-gaap_RelatedPartyTransactionDueFromToRelatedParty / us-gaap_IncomeStatementLocationAxis = gpor_LeaseOperatingExpenseMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_StingrayEnergyServicesLlcMember |  |
Mammoth Energy Partners LP [Member] | Wexford [Member] |  |  |  |
Related Party Transaction [Line Items] |  |  |  |
Other Ownership Interest, Percentage | 69.50%gpor_OtherOwnershipInterestPercentage / us-gaap_CounterpartyNameAxis = gpor_MammothEnergyPartnersLPMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = gpor_WexfordMember |  |  |

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