XML 110 R36.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Accounts Receivable-Related Parties (Narrative) (Details) (USD $) |  |  | 0 Months Ended | 3 Months Ended | 6 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Jun. 30, 2013 | Dec. 31, 2012 | Jul. 02, 2008 Everest Operations Management LLC [Member] | Jun. 30, 2012 Everest Operations Management LLC [Member] | Jun. 30, 2012 Everest Operations Management LLC [Member] | Jul. 01, 2008 Everest Operations Management LLC [Member]
Related Party Transaction [Line Items] |  |  |  |  |  |
Accounts receivable-related parties | $ 36,823,000 | $ 34,848,000 |  |  |  |
Percentage of proportionate share of acquisition or divestiture consideration payable to affiliates |  |  |  |  |  | 1.00%
Required notice period, counterparty |  |  | 30 days |  |  |
Reimbursement for general and administrative expenses performed for related party under acquisition team agreement |  |  |  | $ 200,000 | $ 500,000 |

X
- Definition Cancellation of Agreement Required Written Notice Term, Counterparty + References No definition available. + Details
Name: | gpor_CancellationOfAgreementRequiredWrittenNoticeTermCounterparty
Namespace Prefix: | gpor_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition gpor_PercentageOfProportionateShareOfAcquisitionOrDivestitureConsiderationPayableToAffiliates + References No definition available. + Details
Name: | gpor_PercentageOfProportionateShareOfAcquisitionOrDivestitureConsiderationPayableToAffiliates
Namespace Prefix: | gpor_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Reimbursement for general and administrative expenses performed for related party under acquisition team agreement. + References No definition available. + Details
Name: | gpor_ReimbursementForGeneralAndAdministrativeExpensesPerformedForRelatedPartyUnderAcquisitionTeamAgreement
Namespace Prefix: | gpor_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The aggregate amount of receivables to be collected from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth, at the financial statement date. which are usually due within one year (or one business cycle). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.3(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(k)(1)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 57 -Paragraph 2 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 3 -Subparagraph a -Article 5 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6361293&loc=d3e6676-107765 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph k -Subparagraph 2 -Article 4 + Details
Name: | us-gaap_DueFromRelatedPartiesCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration