Annual report pursuant to Section 13 and 15(d)

Supplemental Oil and Natural Gas Reserve Data (unaudited) (Capitalized Costs) (Details)

v2.4.1.9
Supplemental Oil and Natural Gas Reserve Data (unaudited) (Capitalized Costs) (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended 2 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Feb. 28, 2015
item
Evaluated Properties        
Beginning of period balance $ 1,701,577us-gaap_CapitalizedCostsProvedProperties $ 1,497,010us-gaap_CapitalizedCostsProvedProperties $ 1,421,640us-gaap_CapitalizedCostsProvedProperties  
Capitalized G&A 10,071cpe_CapitalizedCostsProvedPropertiesCapitalizedGeneralAndAdministration 10,014cpe_CapitalizedCostsProvedPropertiesCapitalizedGeneralAndAdministration 12,148cpe_CapitalizedCostsProvedPropertiesCapitalizedGeneralAndAdministration  
Property acquisition costs 94,541us-gaap_CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves 10,885us-gaap_CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves 2,075us-gaap_CostsIncurredAcquisitionOfOilAndGasPropertiesWithProvedReserves  
Exploration costs 118,251cpe_CapitalizedCostsProvedPropertiesExplorationCosts 147,164cpe_CapitalizedCostsProvedPropertiesExplorationCosts 22,703cpe_CapitalizedCostsProvedPropertiesExplorationCosts  
Development costs 153,545cpe_CapitalizedCostsProvedPropertiesDevelopmentCosts 36,504cpe_CapitalizedCostsProvedPropertiesDevelopmentCosts 38,444cpe_CapitalizedCostsProvedPropertiesDevelopmentCosts  
End of period balance 2,077,985us-gaap_CapitalizedCostsProvedProperties 1,701,577us-gaap_CapitalizedCostsProvedProperties 1,497,010us-gaap_CapitalizedCostsProvedProperties  
Unevaluated Properties        
Beginning of period balance 43,222us-gaap_CapitalizedCostsUnprovedProperties 68,776us-gaap_CapitalizedCostsUnprovedProperties 2,603us-gaap_CapitalizedCostsUnprovedProperties  
Property acquisition costs 128,342us-gaap_CostsIncurredAcquisitionOfUnprovedOilAndGasProperties 2,259us-gaap_CostsIncurredAcquisitionOfUnprovedOilAndGasProperties 29,590us-gaap_CostsIncurredAcquisitionOfUnprovedOilAndGasProperties  
Exploration 11,177cpe_CapitalizedCostsUnprovedPropertiesExploration 10,767cpe_CapitalizedCostsUnprovedPropertiesExploration 34,674cpe_CapitalizedCostsUnprovedPropertiesExploration  
Capitalized interest 4,295cpe_CapitalizedCostsUnprovedPropertiesCapitalizedInterest 4,410cpe_CapitalizedCostsUnprovedPropertiesCapitalizedInterest 2,109cpe_CapitalizedCostsUnprovedPropertiesCapitalizedInterest  
Transfers to evaluated (44,511)cpe_CapitalizedCostsUnprovedPropertiesTransfersToEvaluated (42,990)cpe_CapitalizedCostsUnprovedPropertiesTransfersToEvaluated (200)cpe_CapitalizedCostsUnprovedPropertiesTransfersToEvaluated  
End of period balance 142,525us-gaap_CapitalizedCostsUnprovedProperties 43,222us-gaap_CapitalizedCostsUnprovedProperties 68,776us-gaap_CapitalizedCostsUnprovedProperties  
Accumulated depreciation, depletion and amortization:        
Beginning of period balance 1,420,612us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities 1,296,265us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities 1,208,331us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities  
Provision charged to expense 56,663cpe_CapitalizedCostsProvisionChargedToExpenseRelatingToOilAndGasProducingActivities 42,251cpe_CapitalizedCostsProvisionChargedToExpenseRelatingToOilAndGasProducingActivities 48,524cpe_CapitalizedCostsProvisionChargedToExpenseRelatingToOilAndGasProducingActivities  
Sale of mineral interests 1,080cpe_CapitalizedCostsSaleOfMineralInterestsRelatingToOilAndGasProducingActivities 82,096cpe_CapitalizedCostsSaleOfMineralInterestsRelatingToOilAndGasProducingActivities 39,410cpe_CapitalizedCostsSaleOfMineralInterestsRelatingToOilAndGasProducingActivities  
End of period balance $ 1,478,355us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities $ 1,420,612us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities $ 1,296,265us-gaap_CapitalizedCostsAccumulatedDepreciationDepletionAmortizationAndValuationAllowanceForRelatingToOilAndGasProducingActivities  
Depletion Expense Per Physical Unit of Production 27.51cpe_DepletionExpensePerPhysicalUnitOfProduction 31.12cpe_DepletionExpensePerPhysicalUnitOfProduction 31.56cpe_DepletionExpensePerPhysicalUnitOfProduction  
Lease Expense Per Physical Unit of Production 10.85cpe_LeaseExpensePerPhysicalUnitofProduction 14.00cpe_LeaseExpensePerPhysicalUnitofProduction 14.81cpe_LeaseExpensePerPhysicalUnitofProduction  
Subsequent Event [Member]        
Accumulated depreciation, depletion and amortization:        
Number of completed horizontal wells       5cpe_NumberOfCompletedHorizontalWells
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Number of horizontal wells drilled       4us-gaap_DevelopmentWellsDrilledNetProductive
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Number of horizontal wells in progress       2cpe_NumberOfHorizontalWellsInProgress
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Minimum [Member]        
Accumulated depreciation, depletion and amortization:        
Unevaluated Property Costs Expected Evaluation Period Range 3 years      
Maximum [Member]        
Accumulated depreciation, depletion and amortization:        
Unevaluated Property Costs Expected Evaluation Period Range 5 years