XML 110 R92.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) - Results of Operations for Producing Activities (Details) - USD ($) | 12 Months Ended
--- | ---
Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Results of Operations for Oil and Gas Producing Activities [Line Items] |  |  |
Revenues | $ 385,910,000 | $ 708,990,000 | $ 670,762,000
Production costs | (248,125,000) | (222,805,000) | (140,664,000)
Depletion | (243,098,000) | (335,288,000) | (263,946,000)
Impairment | (715,495,000) | (1,440,418,000) | 0
Results of operations, before income taxes | (820,808,000) | (1,289,521,000) | 266,152,000
Income Tax Expense (Benefit), Continuing Operations [Abstract] |  |  |
Current | 0 | 0 | 0
Deferred | 0 | (220,201,000) | 96,061,000
Income tax expense | 0 | (220,201,000) | 96,061,000
Results of operations from producing activities | (820,808,000) | (1,069,320,000) | 170,091,000
Depletion per Mcf of gas equivalent (Mcfe) | 0.92 | 1.68 | 3.01
Investment in Grizzly Oil Sands ULC |  |  |
Results of Operations for Oil and Gas Producing Activities [Line Items] |  |  |
Revenues | 0 | 1,436,000 | 5,449,000
Production costs | (13,000) | (1,549,000) | (10,113,000)
Depletion | 0 | (625,000) | (1,195,000)
Results of operations, before income taxes | (13,000) | (738,000) | (5,859,000)
Income Tax Expense (Benefit), Continuing Operations [Abstract] |  |  |
Income tax expense | 0 | 0 | 0
Results of operations from producing activities | $ (13,000) | $ (738,000) | $ (5,859,000)

X
- Definition Depletion per MCF of Gas Equivalent + References No definition available. + Details
Name: | gpor_DepletionperMCFofGasEquivalent
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Results of operations income tax expense current + References No definition available. + Details
Name: | gpor_ResultsOfOperationsIncomeTaxExpenseCurrent
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Results of operations income tax expense deferred + References No definition available. + Details
Name: | gpor_ResultsOfOperationsIncomeTaxExpenseDeferred
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition [Line Items] for Results of Operations for Oil and Gas Producing Activities [Table] + References No definition available. + Details
Name: | gpor_ResultsofOperationsforOilandGasProducingActivitiesLineItems
Namespace Prefix: | gpor_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=64862545&loc=d3e2921-110230 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=66906256&loc=d3e66150-109466 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585 + Details
Name: | us-gaap_ImpairmentOfOilAndGasProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Depreciation, depletion and amortization, and valuation provisions (impairments) related to oil and gas producing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62136-109447 + Details
Name: | us-gaap_ResultsOfOperationsDepreciationDepletionAndAmortizationAndValuationProvisions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Income before income taxes for oil and gas producing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62136-109447 + Details
Name: | us-gaap_ResultsOfOperationsIncomeBeforeIncomeTaxes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Income tax expense for oil and gas producing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 25 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62259-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62136-109447 + Details
Name: | us-gaap_ResultsOfOperationsIncomeTaxExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The results of operations for oil and gas producing activities, excluding corporate overhead and interest costs. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 26 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62299-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62136-109447 + Details
Name: | us-gaap_ResultsOfOperationsOilAndGasProducingActivitiesNetIncomeExcludingCorporateOverheadAndInterestCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Production (lifting) costs from oil and gas producing activities, including but not limited to lease operating expense, production and ad valorem taxes, and transportation expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62136-109447 + Details
Name: | us-gaap_ResultsOfOperationsProductionOrLiftingCosts
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total revenues from oil and gas producing activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62136-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e62246-109447 + Details
Name: | us-gaap_ResultsOfOperationsRevenueFromOilAndGasProducingActivities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gpor_GrizzlyOilSandsUlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |