XML 69 R55.htm IDEA: XBRL DOCUMENT
v3.19.3

DERIVATIVE INSTRUMENTS (Contingent Consideration Arrangement) (Details) | 9 Months Ended
--- | ---
Sep. 30, 2019 USD ($) $ / shares
Derivative [Line Items] |
Derivative, credit risk related contingent features, payment to be received, denominator (in usd per share) | $ 8.03
Derivative Threshold, Greater Than or Equal to $60.65 |
Derivative [Line Items] |
Payment to be received | $ | $ 150,000
Derivative, credit risk related contingent features, commodity price threshold (in usd per share) | $ 60.65
Derivative Threshold, Between $52.62 and $60.65 |
Derivative [Line Items] |
Derivative, credit risk related contingent features, commodity price threshold (in usd per share) | 52.62
Derivative Threshold, Between $52.62 and $60.65 | Minimum |
Derivative [Line Items] |
Derivative, credit risk related contingent features, commodity price threshold (in usd per share) | 52.62
Derivative Threshold, Between $52.62 and $60.65 | Maximum |
Derivative [Line Items] |
Derivative, credit risk related contingent features, commodity price threshold (in usd per share) | $ 60.65
Derivative Threshold, Less Than or Equal to $52.62 |
Derivative [Line Items] |
Payment to be received | $ | $ 0

X
- Definition Derivative, Credit Risk Related Contingent Features, Commodity Price Threshold + References No definition available. + Details
Name: | gpor_DerivativeCreditRiskRelatedContingentFeaturesCommodityPriceThreshold
Namespace Prefix: | gpor_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Derivative, Credit Risk Related Contingent Features, Payment To Be Received, Denominator + References No definition available. + Details
Name: | gpor_DerivativeCreditRiskRelatedContingentFeaturesPaymentToBeReceivedDenominator
Namespace Prefix: | gpor_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Derivative, Credit Risk Related Contingent Features, Payment to Be Received + References No definition available. + Details
Name: | gpor_DerivativeCreditRiskRelatedContingentFeaturesPaymenttoBeReceived
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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
- Details
Name: | gpor_DerivativeThresholdTermsAxis=gpor_DerivativeThresholdOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | gpor_DerivativeThresholdTermsAxis=gpor_DerivativeThresholdTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | gpor_DerivativeThresholdTermsAxis=gpor_DerivativeThresholdThreeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |