XML 82 R67.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Subsequent Events (Narrative) (Details) shares in Millions | 1 Months Ended | 3 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 31, 2017 MMBTU / d $ / MMBTU shares | Jun. 30, 2017 shares | Apr. 30, 2017 MMBTU / d $ / MMBTU | Dec. 31, 2014
2018 |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Daily Volume | MMBTU / d | 30,000 |  |  |
Weighted average price (in usd per MMB/Bblstu) | $ / MMBTU | 3.36 |  |  |
NYMEX Henry Hub | 2018 |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Daily Volume | MMBTU / d | 543,767 |  |  |
Weighted average price (in usd per MMB/Bblstu) | $ / MMBTU | 3.09 |  |  |
NYMEX Henry Hub | 2019 |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Daily Volume | MMBTU / d | 9,863 |  |  |
Weighted average price (in usd per MMB/Bblstu) | $ / MMBTU | 3.27 |  |  |
Mammoth Energy Services LP |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Equity method investment, ownership interest, percent | 24.20% |  |  | 30.50%
Mammoth Energy Partners LP | Sturgeon Acquisitions LLC, Stingray Energy, and Stingray Cementing |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Shares potentially to be sold (in shares) | shares | 7.0 |  |  |
Subsequent event | NYMEX Henry Hub | 2018 |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Daily Volume | MMBTU / d |  |  | 65,000 |
Weighted average price (in usd per MMB/Bblstu) | $ / MMBTU |  |  | 3.03 |
Subsequent event | NYMEX Henry Hub | 2019 |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Daily Volume | MMBTU / d |  |  | 10,000 |
Weighted average price (in usd per MMB/Bblstu) | $ / MMBTU |  |  | 3.01 |
Forecast | Mammoth Energy Services LP |  |  |  |
Subsequent Event [Line Items] |  |  |  |
Shares received from equity method investee in exchange for ownership interest (in shares) | shares |  | 2.0 |  |
Equity method investment, ownership interest, percent |  | 25.10% |  |

X
- Definition Equity Method Investment, Additional Shares Potentially to be Sold + References No definition available. + Details
Name: | gpor_EquityMethodInvestmentAdditionalSharesPotentiallytobeSold
Namespace Prefix: | gpor_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Equity Method Investment, Shares Received from Equity Method Investee in Exchange for Ownership Interest + References No definition available. + Details
Name: | gpor_EquityMethodInvestmentSharesReceivedfromEquityMethodInvesteeinExchangeforOwnershipInterest
Namespace Prefix: | gpor_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate notional amount of derivative expressed in nonmonetary units. For example, the number of barrels specified in a fuel oil forward purchase contract. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNonmonetaryNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

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: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | gpor_PositionMaturityAxis=gpor_FixedPriceSwap2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | gpor_PositionMaturityAxis=gpor_FixedPriceSwap2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gpor_MammothEnergyServicesLPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=gpor_MammothEnergyPartnersLPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gpor_SturgeonAcquisitionsLLCStingrayEnergyandStingrayCementingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioForecastMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |