Quarterly report pursuant to Section 13 or 15(d)

Equity Investments (Investments Accounted For By The Equity Method) (Details)

v2.4.1.9
Equity Investments (Investments Accounted For By The Equity Method) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Dec. 31, 2014
Oct. 11, 2012
Schedule of Equity Method Investments [Line Items]        
Equity investments and investments in subsidiaries $ 374,971us-gaap_EquityMethodInvestments   $ 369,581us-gaap_EquityMethodInvestments  
(Income) loss from equity method investments (19,975)us-gaap_IncomeLossFromEquityMethodInvestments (128,475)us-gaap_IncomeLossFromEquityMethodInvestments    
Tatex Thailand II, LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 23.50%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiLlcMember
     
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiLlcMember
0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiLlcMember
   
Tatex Thailand III, LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 17.90%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiiLlcMember
     
Equity investments and investments in subsidiaries 0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiiLlcMember
     
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiiLlcMember
49us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TatexThailandIiiLlcMember
   
Grizzly Oil Sands ULC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 24.9999%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_GrizzlyOilSandsUlcMember
     
Equity investments and investments in subsidiaries 167,186us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_GrizzlyOilSandsUlcMember
  180,218us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_GrizzlyOilSandsUlcMember
 
(Income) loss from equity method investments 4,142us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_GrizzlyOilSandsUlcMember
2,001us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_GrizzlyOilSandsUlcMember
   
Bison Drilling And Field Services LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 0.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BisonDrillingAndFieldServicesLlcMember
     
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BisonDrillingAndFieldServicesLlcMember
1,933us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BisonDrillingAndFieldServicesLlcMember
   
Muskie Proppant LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 0.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MuskieHoldingsLlcMember
     
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MuskieHoldingsLlcMember
534us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MuskieHoldingsLlcMember
   
Timber Wolf Terminals LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TimberWolfTerminalsLlcMember
     
Equity investments and investments in subsidiaries 1,007us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TimberWolfTerminalsLlcMember
  1,013us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TimberWolfTerminalsLlcMember
 
(Income) loss from equity method investments 6us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TimberWolfTerminalsLlcMember
0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_TimberWolfTerminalsLlcMember
   
Windsor Midstream LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 22.50%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_WindsorMidstreamLlcMember
     
Equity investments and investments in subsidiaries 32,292us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_WindsorMidstreamLlcMember
  13,505us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_WindsorMidstreamLlcMember
 
(Income) loss from equity method investments (18,787)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_WindsorMidstreamLlcMember
(168)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_WindsorMidstreamLlcMember
   
Stingray Pressure Pumping LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 0.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayPressurePumpingLlcMember
     
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayPressurePumpingLlcMember
513us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayPressurePumpingLlcMember
   
Stingray Cementing LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayCementingLlcMember
     
Equity investments and investments in subsidiaries 2,254us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayCementingLlcMember
  2,647us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayCementingLlcMember
 
(Income) loss from equity method investments 67us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayCementingLlcMember
95us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayCementingLlcMember
   
Blackhawk Midstream LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 48.50%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BlackhawkMidstreamLlcMember
     
Equity investments and investments in subsidiaries 0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BlackhawkMidstreamLlcMember
  0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BlackhawkMidstreamLlcMember
 
(Income) loss from equity method investments (7,217)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BlackhawkMidstreamLlcMember
(84,787)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_BlackhawkMidstreamLlcMember
   
Stingray Logistics LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 0.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayLogisticsLlcMember
     
Equity investments and investments in subsidiaries 0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayLogisticsLlcMember
  0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayLogisticsLlcMember
 
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayLogisticsLlcMember
81us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayLogisticsLlcMember
   
Diamondback Energy, Inc [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 0.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_DiamondbackEnergyIncMember
     
Equity investments and investments in subsidiaries 0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_DiamondbackEnergyIncMember
  0us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_DiamondbackEnergyIncMember
138,500us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_DiamondbackEnergyIncMember
(Income) loss from equity method investments 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_DiamondbackEnergyIncMember
(48,767)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_DiamondbackEnergyIncMember
   
Stingray Energy Services LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 50.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayEnergyServicesLlcMember
     
Equity investments and investments in subsidiaries 6,167us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayEnergyServicesLlcMember
  5,718us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayEnergyServicesLlcMember
 
(Income) loss from equity method investments 10us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayEnergyServicesLlcMember
41us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_StingrayEnergyServicesLlcMember
   
Sturgeon Acquisitions LLC [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 25.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_SturgeonAcquisitionsLLCMember
  25.00%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_SturgeonAcquisitionsLLCMember
 
Equity investments and investments in subsidiaries 22,258us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_SturgeonAcquisitionsLLCMember
  22,507us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_SturgeonAcquisitionsLLCMember
 
(Income) loss from equity method investments (568)us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_SturgeonAcquisitionsLLCMember
0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_SturgeonAcquisitionsLLCMember
   
Mammoth Energy Partners LP [Member]        
Schedule of Equity Method Investments [Line Items]        
Approximate Ownership % 30.50%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MammothEnergyPartnersLPMember
  30.50%us-gaap_EquityMethodInvestmentOwnershipPercentage
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MammothEnergyPartnersLPMember
 
Equity investments and investments in subsidiaries 143,807us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MammothEnergyPartnersLPMember
  143,973us-gaap_EquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MammothEnergyPartnersLPMember
 
(Income) loss from equity method investments $ 2,372us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MammothEnergyPartnersLPMember
$ 0us-gaap_IncomeLossFromEquityMethodInvestments
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= gpor_MammothEnergyPartnersLPMember