XML 68 R56.htm IDEA: XBRL DOCUMENT
v3.21.1

DERIVATIVE INSTRUMENTS (Schedule of Derivative Instruments) (Details) | 3 Months Ended
--- | ---
Mar. 31, 2021 MMBTU $ / bbl $ / MMBTU bbl
NYMEX Henry Hub - Remaining 2021 |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 351,316
Weighted average price (in usd per MMBtu or Bbl) | $ / MMBTU | 2.73
NYMEX WTI - Remaining 2021 |
Derivative [Line Items] |
Daily Volume (Bbl/day) | bbl | 1,505
Weighted average price (in usd per MMBtu or Bbl) | $ / bbl | 53.07
Mont Belvieu C3 - Remaining 2021 |
Derivative [Line Items] |
Daily Volume (Bbl/day) | bbl | 2,074
Weighted average price (in usd per MMBtu or Bbl) | $ / bbl | 27.80
Mont Belvieu C3 - 2022 |
Derivative [Line Items] |
Daily Volume (Bbl/day) | bbl | 496
Weighted average price (in usd per MMBtu or Bbl) | $ / bbl | 27.30
NYMEX Henry Hub - 2022 | Short | Call Option |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 152,675
Weighted average price (in usd per MMBtu or Bbl) | $ / MMBTU | 2.90
NYMEX Henry Hub - 2023 | Short | Call Option |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 627,675
Weighted average price (in usd per MMBtu or Bbl) | $ / MMBTU | 2.90
NYMEX Henry Hub - Remaining 2021 Index1 |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 390,509
Weighted average floor price (in usd per MMBtu) | $ / MMBTU | 2.54
Weighted average ceiling price (in usd per MMBtu) | $ / bbl | 2.93
NYMEX Henry Hub 2022 Index2 |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 186,438
Weighted average floor price (in usd per MMBtu) | $ / MMBTU | 2.63
Weighted average ceiling price (in usd per MMBtu) | $ / bbl | 3.04
Basis Swap, Rex Zone 3 - Remaining 2021 |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 85,309
Weighted average price (in usd per MMBtu or Bbl) | $ / MMBTU | (0.22)
Basis Swap, Tetco M2 - Remaining 2021 |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 32,384
Weighted average price (in usd per MMBtu or Bbl) | $ / MMBTU | (0.63)
Basis Swap, Rex Zone 3 - 2022 |
Derivative [Line Items] |
Daily Volume (MMBtu/day) | 14,795
Weighted average price (in usd per MMBtu or Bbl) | $ / bbl | (0.10)

X
- Definition The average cap rate on a group of price risk derivatives such as caps or collars. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract. + References No definition available. + Details
Name: | us-gaap_DerivativeAverageCapPrice
Namespace Prefix: | us-gaap_
Data Type: | srt-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition The average floor rate on a group of price risk derivatives such as floors or collars. A payment or receipt is triggered if the market rate falls below the floor rate on the contract. + References No definition available. + Details
Name: | us-gaap_DerivativeAverageFloorPrice
Namespace Prefix: | us-gaap_
Data Type: | srt-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal energy measure used to calculate payments on a derivative instrument. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal volume used to calculate payments on a derivative instrument. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountVolume
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average fixed price related to the group of price risk swap derivatives. + References No definition available. + Details
Name: | us-gaap_DerivativeSwapTypeAverageFixedPrice
Namespace Prefix: | us-gaap_
Data Type: | srt-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_NYMEXHenryHubRemaining2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_NYMEXWTIRemaining2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_MontBelvieuC3Remaining2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_MontBelvieuC32022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_NYMEXHenryHub2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PositionAxis=us-gaap_ShortMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OptionIndexedToIssuersEquityEquityAxis=us-gaap_CallOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_NYMEXHenryHub2023Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_NYMEXHenryHubRemaining2021Index1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_NYMEXHenryHub2022Index2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_BasisSwapRexZone3Remaining2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_BasisSwapTetcoM2Remaining2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=gpor_BasisSwapRexZone32022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |