Supplemental Information On Oil And Gas Exploration And Production Activities (Changes in Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves) (Details) (USD $)
In Thousands, unless otherwise specified |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2014
|
Dec. 31, 2013
|
Dec. 31, 2012
|
|
Changes In Standardized Measure of Discontinued Future Net Cash Flows [Line Items] | |||
Sales and transfers of oil and gas produced, net of production costs | $ (530,098)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts | $ (197,559)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts | $ (194,893)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts |
Net changes in prices, production costs, and development costs | 97,716gpor_NetChangesInPricesProductionCostsAndDevelopment | 65,573gpor_NetChangesInPricesProductionCostsAndDevelopment | 108,941gpor_NetChangesInPricesProductionCostsAndDevelopment |
Acquisition of oil and gas reserves in place | 14,266us-gaap_IncreaseDueToPurchasesOfMineralsInPlace | 0us-gaap_IncreaseDueToPurchasesOfMineralsInPlace | 0us-gaap_IncreaseDueToPurchasesOfMineralsInPlace |
Extensions and discoveries | 790,533us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts | 130,826us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts | 151,654us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts |
Previously estimated development costs incurred during the period | 68,227us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod | 43,478us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod | 10,211us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod |
Revisions of previous quantity estimates, less related production costs | (37,801)us-gaap_RevisionsOfPreviousQuantityEstimates | (3,591)us-gaap_RevisionsOfPreviousQuantityEstimates | (10,504)us-gaap_RevisionsOfPreviousQuantityEstimates |
Sales of reserves in place | 0us-gaap_DecreaseDueToSalesOfMineralsInPlace | 0us-gaap_DecreaseDueToSalesOfMineralsInPlace | (214,867)us-gaap_DecreaseDueToSalesOfMineralsInPlace |
Accretion of discount | 57,847us-gaap_AccretionOfDiscount | 34,864us-gaap_AccretionOfDiscount | 37,668us-gaap_AccretionOfDiscount |
Net changes in income taxes | (295,226)us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves | (30,239)us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves | 25,585us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves |
Change in production rates and other | 683,237gpor_ChangeInProductionRatesAndOther | 186,473gpor_ChangeInProductionRatesAndOther | 58,165gpor_ChangeInProductionRatesAndOther |
Total change in standardized measure of discounted future net cash flows | 848,701us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease | 229,825us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease | (28,040)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease |
Diamondback Energy, Inc [Member] | |||
Changes In Standardized Measure of Discontinued Future Net Cash Flows [Line Items] | |||
Sales and transfers of oil and gas produced, net of production costs |
0us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(12,524)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(11,601)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Net changes in prices, production costs, and development costs |
0gpor_NetChangesInPricesProductionCostsAndDevelopment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
3,312gpor_NetChangesInPricesProductionCostsAndDevelopment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(14,596)gpor_NetChangesInPricesProductionCostsAndDevelopment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Acquisition of oil and gas reserves in place |
0us-gaap_IncreaseDueToPurchasesOfMineralsInPlace / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
21,968us-gaap_IncreaseDueToPurchasesOfMineralsInPlace / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
23,090us-gaap_IncreaseDueToPurchasesOfMineralsInPlace / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Extensions and discoveries |
0us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
39,776us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
16,969us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Previously estimated development costs incurred during the period |
0us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
5,517us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
19,014us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Revisions of previous quantity estimates, less related production costs |
0us-gaap_RevisionsOfPreviousQuantityEstimates / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(9,143)us-gaap_RevisionsOfPreviousQuantityEstimates / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(4,897)us-gaap_RevisionsOfPreviousQuantityEstimates / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Accretion of discount |
0us-gaap_AccretionOfDiscount / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
4,175us-gaap_AccretionOfDiscount / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
7,803us-gaap_AccretionOfDiscount / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Net changes in income taxes |
0us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(12,137)us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(26,866)us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Change in production rates and other |
0gpor_ChangeInProductionRatesAndOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
2,862gpor_ChangeInProductionRatesAndOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(8,358)gpor_ChangeInProductionRatesAndOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Total change in standardized measure of discounted future net cash flows |
0us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(8,339)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
558us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Equity Method Investment, Change in Ownership |
0gpor_EquityMethodInvestmentChangeinOwnership / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
(52,145)gpor_EquityMethodInvestmentChangeinOwnership / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
0gpor_EquityMethodInvestmentChangeinOwnership / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember |
Grizzly Oil Sands ULC [Member] | |||
Changes In Standardized Measure of Discontinued Future Net Cash Flows [Line Items] | |||
Sales and transfers of oil and gas produced, net of production costs |
(4,664)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Net changes in prices, production costs, and development costs |
76,518gpor_NetChangesInPricesProductionCostsAndDevelopment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0gpor_NetChangesInPricesProductionCostsAndDevelopment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0gpor_NetChangesInPricesProductionCostsAndDevelopment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Acquisition of oil and gas reserves in place |
0us-gaap_IncreaseDueToPurchasesOfMineralsInPlace / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_IncreaseDueToPurchasesOfMineralsInPlace / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_IncreaseDueToPurchasesOfMineralsInPlace / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Extensions and discoveries |
7,107us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Previously estimated development costs incurred during the period |
0us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_PreviouslyEstimatedDevelopmentCostsIncurredDuringPeriod / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Revisions of previous quantity estimates, less related production costs |
(10,659)us-gaap_RevisionsOfPreviousQuantityEstimates / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_RevisionsOfPreviousQuantityEstimates / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_RevisionsOfPreviousQuantityEstimates / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Accretion of discount |
14,946us-gaap_AccretionOfDiscount / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_AccretionOfDiscount / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_AccretionOfDiscount / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Net changes in income taxes |
9,162us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Change in production rates and other |
(25,738)gpor_ChangeInProductionRatesAndOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0gpor_ChangeInProductionRatesAndOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
0gpor_ChangeInProductionRatesAndOther / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
Total change in standardized measure of discounted future net cash flows |
$ (55,718)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
$ 0us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
$ 0us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember |
X | ||||||||||
- Definition
Change in production rates and other No definition available.
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X | ||||||||||
- Details
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X | ||||||||||
- Definition
Equity Method Investment, Change in Ownership No definition available.
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X | ||||||||||
- Definition
Net change in sales and transfer prices and in production (lifting) costs related to future production and in the evaluation of the costs that will be required in future periods to make it possible to extract or process proved oil and gas reserves. No definition available.
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X | ||||||||||
- Definition
Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of decrease in standardized measure of discounted future net cash flow as a result of sales of minerals in place. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of extensions, discoveries and improved recovery of proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of change in the estimated future income tax on future pretax net cash flows related to the entity's proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of increase in standardized measure of discounted future net cash flow as a result of purchases of minerals in place. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of (increase) decrease in standardized measure of discounted future net cash flow as a result of previously estimated development costs incurred. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of increase (decrease) in standardized measure of discounted future net cash flow as a result of revisions of estimated quantity of oil and gas in proved reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of (increase) decrease in standardized measure of discounted future net cash flow as a result of sales and transfers of oil and gas produced. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Definition
Amount of increase (decrease) in standardized measure of discounted future net cash flow relating to proved oil and gas reserves. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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X | ||||||||||
- Details
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X | ||||||||||
- Details
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