XML 92 R75.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Derivative Instruments - Gain (Loss) on Derivative Instruments (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Derivative [Line Items] |  |  |
Gain due to changes in fair value of derivative instruments | $ (123,479) | $ 213,679 | $ (174,506)
Natural gas derivatives |  |  |
Derivative [Line Items] |  |  |
Gain due to changes in fair value of derivative instruments | (116,130) | 232,143 | (165,933)
Oil derivatives |  |  |
Derivative [Line Items] |  |  |
Gain due to changes in fair value of derivative instruments | (13,084) | (3,350) | (5,387)
Natural gas liquids derivatives |  |  |
Derivative [Line Items] |  |  |
Gain due to changes in fair value of derivative instruments | $ 5,735 | $ (15,114) | $ (3,186)

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 Amount of gain (loss)recognized in the income statement from the hedging ineffectiveness of a fair value hedge. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 50 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=109977999&loc=d3e76258-113986 + Details
Name: | us-gaap_GainLossOnFairValueHedgeIneffectivenessNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_EnergyAxis=gpor_GasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnergyAxis=srt_OilReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnergyAxis=srt_NaturalGasReservesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |