XML 69 R57.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Derivative Instruments (Narrative) (Details) - 2019 | 3 Months Ended
--- | ---
Mar. 31, 2018 MMBTU $ / MMBTU
Derivative [Line Items] |
Daily volume (in MMBtu) | MMBTU | 100,000
Weighted average price (in usd per MMBtu or Bbl) | $ / MMBTU | 3.05

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