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Consolidated Balance Sheets (USD $)
In Thousands, unless otherwise specified |
Mar. 31, 2015
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Dec. 31, 2014
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|---|---|---|
| Current assets: | ||
| Cash and cash equivalents | $ 74,740us-gaap_CashAndCashEquivalentsAtCarryingValue | $ 142,340us-gaap_CashAndCashEquivalentsAtCarryingValue |
| Accounts receivable—oil and gas | 79,680us-gaap_AccountsReceivableNetCurrent | 103,858us-gaap_AccountsReceivableNetCurrent |
| Accounts receivable—related parties | 33us-gaap_DueFromRelatedPartiesCurrent | 46us-gaap_DueFromRelatedPartiesCurrent |
| Prepaid expenses and other current assets | 15,777us-gaap_PrepaidExpenseAndOtherAssetsCurrent | 3,714us-gaap_PrepaidExpenseAndOtherAssetsCurrent |
| Short-term derivative instruments | 93,030us-gaap_DerivativeAssetsCurrent | 78,391us-gaap_DerivativeAssetsCurrent |
| Total current assets | 263,260us-gaap_AssetsCurrent | 328,349us-gaap_AssetsCurrent |
| Property and equipment: | ||
| Oil and natural gas properties, full-cost accounting, $1,546,804 and $1,465,538 excluded from amortization in 2015 and 2014, respectively | 4,177,962us-gaap_OilAndGasPropertyFullCostMethodGross | 3,923,154us-gaap_OilAndGasPropertyFullCostMethodGross |
| Other property and equipment | 19,051us-gaap_PropertyPlantAndEquipmentOther | 18,344us-gaap_PropertyPlantAndEquipmentOther |
| Accumulated depletion, depreciation, amortization and impairment | (1,140,168)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment | (1,050,879)us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment |
| Property and equipment, net | 3,056,845us-gaap_PropertyPlantAndEquipmentNet | 2,890,619us-gaap_PropertyPlantAndEquipmentNet |
| Other assets: | ||
| Equity investments | 374,971us-gaap_EquityMethodInvestments | 369,581us-gaap_EquityMethodInvestments |
| Derivative instruments | 41,956us-gaap_DerivativeInstrumentsAndHedgesNoncurrent | 24,448us-gaap_DerivativeInstrumentsAndHedgesNoncurrent |
| Other assets | 18,566us-gaap_OtherAssetsNoncurrent | 19,396us-gaap_OtherAssetsNoncurrent |
| Total other assets | 435,493gpor_TotalOtherAssets | 413,425gpor_TotalOtherAssets |
| Total assets | 3,755,598us-gaap_Assets | 3,632,393us-gaap_Assets |
| Current liabilities: | ||
| Accounts payable and accrued liabilities | 400,096us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent | 371,410us-gaap_AccountsPayableAndAccruedLiabilitiesCurrent |
| Asset retirement obligation—current | 75us-gaap_AssetRetirementObligationCurrent | 75us-gaap_AssetRetirementObligationCurrent |
| Deferred tax liability | 29,622us-gaap_DeferredTaxLiabilitiesCurrent | 27,070us-gaap_DeferredTaxLiabilitiesCurrent |
| Short-term derivative instruments | 823us-gaap_DerivativeLiabilitiesCurrent | |
| Current maturities of long-term debt | 1,781us-gaap_LongTermDebtCurrent | 168us-gaap_LongTermDebtCurrent |
| Total current liabilities | 432,397us-gaap_LiabilitiesCurrent | 398,723us-gaap_LiabilitiesCurrent |
| Asset retirement obligation—long-term | 18,656us-gaap_AssetRetirementObligationsNoncurrent | 17,863us-gaap_AssetRetirementObligationsNoncurrent |
| Deferred tax liability | 215,122us-gaap_DeferredTaxLiabilitiesGrossNoncurrent | 203,195us-gaap_DeferredTaxLiabilitiesGrossNoncurrent |
| Long-term debt, net of current maturities | 779,130us-gaap_LongTermDebtNoncurrent | 716,316us-gaap_LongTermDebtNoncurrent |
| Total liabilities | 1,445,305us-gaap_Liabilities | 1,336,097us-gaap_Liabilities |
| Commitments and contingencies (Note 8) | ||
| Preferred stock, $.01 par value; 5,000,000 authorized, 30,000 authorized as redeemable 12% cumulative preferred stock, Series A; 0 issued and outstanding | 0us-gaap_PreferredStockValue | 0us-gaap_PreferredStockValue |
| Stockholders’ equity: | ||
| Common stock - $.01 par value, 200,000,000 authorized, 85,715,819 issued and outstanding in 2015 and 85,655,438 in 2014 | 857us-gaap_CommonStockValue | 856us-gaap_CommonStockValue |
| Paid-in capital | 1,832,063us-gaap_AdditionalPaidInCapital | 1,828,602us-gaap_AdditionalPaidInCapital |
| Accumulated other comprehensive loss | (41,659)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax | (26,675)us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax |
| Retained earnings | 519,032us-gaap_RetainedEarningsAccumulatedDeficit | 493,513us-gaap_RetainedEarningsAccumulatedDeficit |
| Total stockholders’ equity | 2,310,293us-gaap_StockholdersEquity | 2,296,296us-gaap_StockholdersEquity |
| Total liabilities and stockholders’ equity | $ 3,755,598us-gaap_LiabilitiesAndStockholdersEquity | $ 3,632,393us-gaap_LiabilitiesAndStockholdersEquity |
| X | ||||||||||
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- Definition
The sum of all other long-term assets, not including property, plant and equipment. No definition available.
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| X | ||||||||||
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- Definition
Sum of the carrying values as of the balance sheet date of obligations incurred through that date and due within one year (or the operating cycle, if longer), including liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received, taxes, interest, rent and utilities, accrued salaries and bonuses, payroll taxes and fringe benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Represents the caption on the face of the balance sheet to indicate that the entity has entered into (1) purchase or supply arrangements that will require expending a portion of its resources to meet the terms thereof, and (2) is exposed to potential losses or, less frequently, gains, arising from (a) possible claims against a company's resources due to future performance under contract terms, and (b) possible losses or likely gains from uncertainties that will ultimately be resolved when one or more future events that are deemed likely to occur do occur or fail to occur. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences, netted by jurisdiction and classified as current. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Gross amount of noncurrent deferred tax liabilities, which result from applying the applicable tax rate to taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Fair value, after the effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Carrying amount as of the balance sheet date of the assets arising from derivative contracts and hedging activities, which are expected to be converted into cash or otherwise disposed of after a year or beyond the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, expected to be settled within one year or normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- 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). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Sum of the carrying amounts as of the balance sheet date of all liabilities that are recognized. Liabilities are probable future sacrifices of economic benefits arising from present obligations of an entity to transfer assets or provide services to other entities in the future. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of liabilities and equity items, including the portion of equity attributable to noncontrolling interests, if any. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
Amount of long-term debt, after unamortized discount or premium, scheduled to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Oil and gas properties, gross, carried under the full cost method. No definition available.
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| X | ||||||||||
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- Definition
Aggregate carrying amount, as of the balance sheet date, of noncurrent assets not separately disclosed in the balance sheet. Noncurrent assets are expected to be realized or consumed after one year (or the normal operating cycle, if longer). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount of asset related to consideration paid in advance for costs that provide economic benefits in future periods, and amount of other assets that are expected to be realized or consumed within one year or the normal operating cycle, if longer. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
Amount before accumulated depreciation, depletion and amortization of other physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
The cumulative amount of the reporting entity's undistributed earnings or deficit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Details
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