Annual report pursuant to Section 13 and 15(d)

Supplemental Oil and Natural Gas Reserve Data (unaudited) (Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves) (Details)

v2.4.1.9
Supplemental Oil and Natural Gas Reserve Data (unaudited) (Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves) (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Future Net Cash Flows [Abstract]      
Future cash inflows $ 2,492,178us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows $ 1,193,299us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows $ 1,115,570us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesCashInflows
Production (873,469)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts (357,005)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts (249,329)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesProductionCosts
Development and net abandonment (288,081)cpe_DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesFutureDevelopmentCostsAndNetAbandonment (155,667)cpe_DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesFutureDevelopmentCostsAndNetAbandonment (273,817)cpe_DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesFutureDevelopmentCostsAndNetAbandonment
Future net inflows before income taxes 1,330,628cpe_DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesFutureNetInflowsBeforeIncomeTaxes 680,627cpe_DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesFutureNetInflowsBeforeIncomeTaxes 592,424cpe_DiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReservesFutureNetInflowsBeforeIncomeTaxes
Future income taxes (164,490)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense (68,239)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense (55,772)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesIncomeTaxExpense
Future net cash flows 1,166,138us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows 612,388us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows 536,652us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesNetCashFlows
10% discount factor (586,596)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows (328,442)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows (305,504)us-gaap_FutureNetCashFlowsRelatingToProvedOilAndGasReservesTenPercentAnnualDiscountForEstimatedTimingOfCashFlows
Standardized Measure of Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Total 579,542us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves 283,946us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves 231,148us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves
Increase (Decrease) in Standardized Measure of Discounted Future Net Cash Flow Relating to Proved Oil and Gas Reserves [Roll Forward]      
Standardized measure at the beginning of the period 283,946us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves 231,148us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves 270,357us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves
Sales and transfers, net of production costs (120,518)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts (78,661)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts (84,044)us-gaap_SalesAndTransfersOfOilAndGasProducedNetOfProductionCosts
Net change in sales and transfer prices, net of production costs (156,066)us-gaap_NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts (46,088)us-gaap_NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts 47,261us-gaap_NetIncreaseDecreaseInSalesAndTransferPricesAndProductionCosts
Net change due to purchases and sales of in place reserves 111,331cpe_NetChangeDueToPurchasesAndSalesOfInPlaceReserves (145,711)cpe_NetChangeDueToPurchasesAndSalesOfInPlaceReserves (35,665)cpe_NetChangeDueToPurchasesAndSalesOfInPlaceReserves
Extensions, discoveries, and improved recovery, net of future production and development costs incurred 299,192us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts 212,431us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts 53,446us-gaap_ExtensionsDiscoveriesAdditionsAndImprovedRecoveryLessRelatedCosts
Changes in future development cost 186,605us-gaap_IncreaseDecreaseInEstimatedFutureDevelopmentCosts 153,983us-gaap_IncreaseDecreaseInEstimatedFutureDevelopmentCosts 39,815us-gaap_IncreaseDecreaseInEstimatedFutureDevelopmentCosts
Revisions of quantity estimates (7,673)us-gaap_RevisionsOfPreviousQuantityEstimates (68,958)us-gaap_RevisionsOfPreviousQuantityEstimates (77,322)us-gaap_RevisionsOfPreviousQuantityEstimates
Accretion of discount 30,114us-gaap_AccretionOfDiscount 25,010us-gaap_AccretionOfDiscount 30,989us-gaap_AccretionOfDiscount
Net change in income taxes (32,940)us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves 1,751us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves 13,969us-gaap_IncreaseDecreaseInFutureIncomeTaxExpenseEstimatesOnFutureCashFlowsRelatedToProvedOilAndGasReserves
Changes in production rates, timing and other (14,449)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesOther (959)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesOther (27,658)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesOther
Aggregate change 295,596us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease 52,798us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease (39,209)us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowOfProvedOilAndGasReservesPeriodIncreaseDecrease
Standardized measure at the end of the period $ 579,542us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves $ 283,946us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves $ 231,148us-gaap_StandardizedMeasureOfDiscountedFutureNetCashFlowsRelatingToProvedOilAndGasReserves