XML 101 R85.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Contingencies - Narrative (Details) |  |  | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Jul. 29, 2016 defendant | Feb. 09, 2016 defendant | Jul. 29, 2016 claim | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Loss Contingencies [Line Items] |  |  |  |  |  |
Number of new claims filed | claim |  |  | 2 |  |  |
Insurance proceeds |  |  |  | $ 0 | $ (5,718,000) | $ (10,015,000)
Uninsured cash amount |  |  |  | 97,600,000 |  |
Maximum |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Cash, FDIC insured amount |  |  |  | $ 250,000 |  |
Judicial District Court for the Parish of Cameron |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Number of defendants | defendant |  | 26 |  |  |  |
Judicial District Court for the Parish of Vermillion |  |  |  |  |  |
Loss Contingencies [Line Items] |  |  |  |  |  |
Number of defendants | defendant | 40 |  |  |  |  |

X
- Definition The amount of cash deposited in financial institutions as of the balance sheet date that is insured by the Federal Deposit Insurance Corporation. + References No definition available. + Details
Name: | us-gaap_CashFDICInsuredAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount of cash as of the balance sheet date that is not insured by the Federal Deposit Insurance Corporation. + References No definition available. + Details
Name: | us-gaap_CashUninsuredAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount recovered from insurance. These recoveries reduce costs and losses that are reported as a separate line item under operating expenses. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.3) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 + Details
Name: | us-gaap_InsuranceRecoveries
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_LossContingenciesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The total number of new claims filed pertaining to a loss contingency during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -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
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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