Annual report pursuant to Section 13 and 15(d)

Related Party Transactions (Details)

v2.4.1.9
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 $ 52,191,000us-gaap_LeaseOperatingExpense $ 26,703,000us-gaap_LeaseOperatingExpense $ 24,308,000us-gaap_LeaseOperatingExpense  
General and administrative 38,290,000us-gaap_GeneralAndAdministrativeExpense 22,519,000us-gaap_GeneralAndAdministrativeExpense 13,808,000us-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   900,000us-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   73,400,000us-gaap_RevenueFromRelatedParties
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_WindsorOhioLlcMember
   
Stingray Pressure Pumping LLC [Member]        
Related Party Transaction [Line Items]        
Due from (to) related party   8,300,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayPressurePumpingLlcMember
   
Oil and natural gas properties 78,300,000gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayPressurePumpingLlcMember
58,300,000gpor_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 800,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayCementingLlcMember
1,500,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayCementingLlcMember
   
Oil and natural gas properties 6,000,000gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayCementingLlcMember
4,000,000gpor_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 6,000,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayEnergyServicesLlcMember
4,100,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayEnergyServicesLlcMember
   
Oil and natural gas properties 24,800,000gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayEnergyServicesLlcMember
5,100,000gpor_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   1,000,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_AthenaConstructionLlcMember
   
Lease operating expenses   600,000us-gaap_LeaseOperatingExpense
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_AthenaConstructionLlcMember
   
Oil and natural gas properties   4,100,000gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_AthenaConstructionLlcMember
   
Panther Drilling Systems, LLC [Member]        
Related Party Transaction [Line Items]        
Due from (to) related party 2,400,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_PantherDrillingSystemsLLCMember
1,800,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_PantherDrillingSystemsLLCMember
   
Oil and natural gas properties 7,600,000gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_PantherDrillingSystemsLLCMember
12,600,000gpor_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
0us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_RedbackDirectionalServicesLLCMember
   
Oil and natural gas properties 1,000,000gpor_OilAndGasPropertyFullCostMethodAmountsCapitalizedDuringPeriod
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_RedbackDirectionalServicesLLCMember
100,000gpor_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 28,400,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_MuskieHoldingsLlcMember
     
Oil and natural gas properties 11,100,000gpor_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   200,000us-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 $ 1,300,000us-gaap_RelatedPartyTransactionDueFromToRelatedParty
/ us-gaap_IncomeStatementLocationAxis
= gpor_LeaseOperatingExpenseMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= gpor_StingrayEnergyServicesLlcMember
$ 1,300,000us-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