XML 87 R91.htm IDEA: XBRL DOCUMENT v2.4.1.9

Supplemental Information On Oil And Gas Exploration And Production Activities (Capitalized Costs Related to Oil and Gas Producing Activities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Reserve Quantities [Line Items]
Proven properties	$ 2,457,616us-gaap_CapitalizedCostsProvedProperties	$ 1,526,588us-gaap_CapitalizedCostsProvedProperties
Unproven properties	1,465,538us-gaap_CapitalizedCostsUnprovedProperties	950,590us-gaap_CapitalizedCostsUnprovedProperties
Capitalized costs, gross	3,923,154us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross	2,477,178us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross
Accumulated depreciation, depletion, amortization and impairment reserve	(1,044,273)us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities	(779,561)us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities
Net capitalized costs	2,878,881us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet	1,697,617us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet
Diamondback Energy, Inc [Member]
Reserve Quantities [Line Items]
Proven properties	0us-gaap_CapitalizedCostsProvedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember	92,074us-gaap_CapitalizedCostsProvedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember
Unproven properties	0us-gaap_CapitalizedCostsUnprovedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember	26,608us-gaap_CapitalizedCostsUnprovedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember
Capitalized costs, gross	0us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember	118,682us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember
Accumulated depreciation, depletion, amortization and impairment reserve	0us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember	(15,180)us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember
Net capitalized costs	0us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember	103,502us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_DiamondbackEnergyIncMember
Grizzly Oil Sands ULC [Member]
Reserve Quantities [Line Items]
Proven properties	96,859us-gaap_CapitalizedCostsProvedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember	0us-gaap_CapitalizedCostsProvedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember
Unproven properties	103,160us-gaap_CapitalizedCostsUnprovedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember	0us-gaap_CapitalizedCostsUnprovedProperties / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember
Capitalized costs, gross	200,019us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember	0us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember
Accumulated depreciation, depletion, amortization and impairment reserve	(1,248)us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember	0us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember
Net capitalized costs	$ 198,771us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember	$ 0us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = gpor_GrizzlyOilSandsUlcMember

X

- Definition

Amount of accumulated depreciation, depletion, amortization and valuation allowance relating 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 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The sum of capitalized costs relating to oil and gas producing activities before accounting for accumulated depreciation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsOilAndGasProducingActivitiesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Net amount of capitalized costs relating 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 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447

+ Details

Name:	us-gaap_CapitalizedCostsOilAndGasProducingActivitiesNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Capitalized costs of proved properties incurred for any combination mineral interests acquisitions; wells and related equipment; support equipment and facilities; and uncompleted wells and equipment and other costs not previously disclosed within this table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Glossary Proved Properties

-URI http://asc.fasb.org/extlink&oid=6522428



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Properties

-URI http://asc.fasb.org/extlink&oid=21914647

+ Details

Name:	us-gaap_CapitalizedCostsProvedProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Capitalized costs of unproved properties incurred for any combination mineral interests acquisitions and other costs not previously disclosed within this table.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e61901-109447



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Properties

-URI http://asc.fasb.org/extlink&oid=21914647



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-Glossary Unproved Properties

-URI http://asc.fasb.org/extlink&oid=6527831

+ Details

Name:	us-gaap_CapitalizedCostsUnprovedProperties
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_ReserveQuantitiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=gpor_DiamondbackEnergyIncMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

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