XML 62 R51.htm IDEA: XBRL DOCUMENT
v3.19.1

COMMITTMENTS AND CONTINGENCIES (Narrative) (Details) $ in Thousands |  |  |  | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | --- | ---
Jul. 29, 2016 complaint defendant | Feb. 09, 2016 complaint defendant | Mar. 11, 1997 | Mar. 31, 2019 USD ($) well | Mar. 31, 2018 USD ($) | Jul. 29, 2016 complaint | Dec. 31, 1997 USD ($) well
Commitments [Line Items] |  |  |  |  |  |  |
Plugging and abandonment trust on the WCBB properties |  |  |  | $ 3,100 |  |  |
Firm transportation contracted with third parties |  |  |  | 66,000 |  |  |
Number of claims filed (in claims) | complaint |  |  |  |  |  | 2 |
Judicial District Court for the Parish of Cameron |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |
Number of claims filed (in claims) | complaint |  | 1 |  |  |  |  |
Number of defendants (in defendants) | defendant |  | 26 |  |  |  |  |
Judicial District Court for the Parish of Vermillion |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |
Number of claims filed (in claims) | complaint | 1 |  |  |  |  |  |
Number of defendants (in defendants) | defendant | 40 |  |  |  |  |  |
Transportation commitment |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |
Firm transportation contracted with third parties |  |  |  | 3,728,767 |  |  |
Future minimum commitments |  |  |  | 191,493 |  |  |
Loss on long-term purchase commitment | Muskie Proppant LLC |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |
Non-utilization fees, accrued damages year to date |  |  |  | $ 300 | $ 900 |  |
WCBB |  |  |  |  |  |  |
Commitments [Line Items] |  |  |  |  |  |  |
Remaining interest in oil and gas property acquisition, percent |  |  |  |  |  |  | 50.00%
Payments of seller's obligation to contribute |  |  |  |  |  |  | $ 18
Minimum number of wells to be plugged (in wells) | well |  |  |  |  |  |  | 20
Tenure of minimum wells to be plugged (in years) |  |  | 20 years |  |  |  |
Number of wells plugged (in wells) | well |  |  |  | 555 |  |  |

X
- Definition Commitments [Line Items] + References No definition available. + Details
Name: | gpor_CommitmentsLineItems
Namespace Prefix: | gpor_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Wells Plugged + References No definition available. + Details
Name: | gpor_NumberOfWellsPlugged
Namespace Prefix: | gpor_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition payments to plugging and abandonment escrow account. + References No definition available. + Details
Name: | gpor_PaymentsHeldForRestrictedCash
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Plugging And Abandonment Escrow Account + References No definition available. + Details
Name: | gpor_PluggingAndAbandonmentEscrowAccount
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Purchasing remaining percent interest in oil and gas property. + References No definition available. + Details
Name: | gpor_PurchasingRemainingPercentInterestInOilAndGasProperty
Namespace Prefix: | gpor_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum number of wells required to be plugged annually. + References No definition available. + Details
Name: | gpor_SignificantPluggingCommitmentMinimumNumberOfWellsToBePlugged
Namespace Prefix: | gpor_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tenure of minimum wells to be plugged + References No definition available. + Details
Name: | gpor_TenureOfMinimumWellsToBePlugged
Namespace Prefix: | gpor_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of loss pertaining to the specified contingency that was charged against earnings in the period, including the effects of revisions in previously reported estimates. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349 + Details
Name: | us-gaap_LossContingencyLossInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The total number of new claims filed pertaining to a loss contingency during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14435-108349 + Details
Name: | us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of defendants named in a legal action. + References No definition available. + Details
Name: | us-gaap_LossContingencyNumberOfDefendants
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions. + References No definition available. + Details
Name: | us-gaap_OtherCommitment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of other commitments maturing in the remainder of the fiscal year following the latest fiscal year ended. + References No definition available. + Details
Name: | us-gaap_OtherCommitmentsFutureMinimumPaymentsRemainderOfFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | srt_LitigationCaseAxis=gpor_JudicialDistrictCourtfortheParishofCameronMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=gpor_JudicialDistrictCourtfortheParishofVermillionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_OtherCommitmentsAxis=gpor_TransportationCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_LossOnLongTermPurchaseCommitmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gpor_MuskieProppantLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=gpor_WcbbMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |