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Income Taxes - Significant Components of Deferred Tax Assets and Liabilities (Details) (USD $)
In Thousands, unless otherwise specified |
Dec. 31, 2014
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Dec. 31, 2013
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| Deferred tax liabilities: | ||
| Property and equipment | $ 518,566us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment | $ 422,805us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment |
| Other | 5,019us-gaap_DeferredTaxLiabilitiesOther | 3,602us-gaap_DeferredTaxLiabilitiesOther |
| Total deferred tax liabilities | 523,585us-gaap_DeferredTaxLiabilities | 426,407us-gaap_DeferredTaxLiabilities |
| Deferred tax assets: | ||
| Alternative minimum tax credit | 20,486us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax | 20,486us-gaap_DeferredTaxAssetsTaxCreditCarryforwardsAlternativeMinimumTax |
| Asset retirement obligations | 137,597us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations | 124,863us-gaap_DeferredTaxAssetsTaxDeferredExpenseReservesAndAccrualsAssetRetirementObligations |
| Federal net operating losses | 180,024us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic | 91,472us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsDomestic |
| State net operating losses | 5,008us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal | 5,028us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsStateAndLocal |
| Derivatives | 3,270us-gaap_DeferredTaxAssetsDerivativeInstruments | |
| Valuation allowance (state) | (4,255)us-gaap_DeferredTaxAssetsValuationAllowance | (4,490)us-gaap_DeferredTaxAssetsValuationAllowance |
| Accrued cash-based bonus | 3,559us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBonuses | 3,873us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsEmployeeBonuses |
| Stock-based compensation | 5,042us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost | 3,703us-gaap_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsShareBasedCompensationCost |
| Other | 798us-gaap_DeferredTaxAssetsOther | 643us-gaap_DeferredTaxAssetsOther |
| Total deferred tax assets | 348,259us-gaap_DeferredTaxAssetsNet | 248,848us-gaap_DeferredTaxAssetsNet |
| Net deferred tax liabilities | $ 175,326us-gaap_DeferredTaxAssetsLiabilitiesNet | $ 177,559us-gaap_DeferredTaxAssetsLiabilitiesNet |
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from derivative instruments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax credit carryforwards. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from employee bonuses. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from asset retirement obligations. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Definition
Amount of deferred tax liability attributable to taxable temporary differences not separately disclosed. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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