XML 66 R55.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Derivative Instruments (Narrative) (Details) | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2017 MMBTU $ / MMBTU | Jun. 30, 2017 $ / MMBTU
Derivative [Line Items] |  |
Derivative, extension option term |  | 12 months
2018 |  |
Derivative [Line Items] |  |
Daily Volume (in MMBtu) | MMBTU | 30,000 |
Weighted average price (in usd per MMBtu or Bbls) | $ / MMBTU | 3.36 | 3.36
2018 | Short |  |
Derivative [Line Items] |  |
Daily Volume (in MMBtu) | MMBTU | 30,000 |
Weighted average price (in usd per MMBtu or Bbls) | $ / MMBTU | 3.36 | 3.36

X
- Definition Derivative, Extension Option Term + References No definition available. + Details
Name: | gpor_DerivativeExtensionOptionTerm
Namespace Prefix: | gpor_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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_FixedPriceSwap2018Member
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: |