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Stock-Based Compensation (Narrative) (Details) (USD $)
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12 Months Ended | ||
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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| Share-based Compensation [Abstract] | |||
| Stock-based compensation expense | $ 14,900,000us-gaap_AllocatedShareBasedCompensationExpense | $ 10,500,000us-gaap_AllocatedShareBasedCompensationExpense | $ 4,700,000us-gaap_AllocatedShareBasedCompensationExpense |
| Capitalized stock-based compensation | 5,944,000gpor_CapitalizedStockBasedCompensation | 4,198,000gpor_CapitalizedStockBasedCompensation | 1,875,000gpor_CapitalizedStockBasedCompensation |
| Unrecognized compensation expense | $ 17,900,000us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized | ||
| Weighted average period | 1 year 5 months 26 days | ||
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- Definition
Non-cash stock based compensation capitalized. No definition available.
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- Definition
Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Unrecognized cost of unvested share-based compensation awards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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