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Derivative Financial Instruments (Details) | Mar. 31, 2015 bbl | Apr. 29, 2015 bbl
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Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 12,100,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember |
Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 204,700,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember |
IF El Paso Permian [Member] |  |
Derivative Financial Instruments |  |
Index percent of natural gas fixed swaps | 2.00%sm_IndexPercentOfNaturalGasFixedSwaps / us-gaap_DerivativeByNatureAxis = sm_IfElPasoPermianMember |
Index percent of natural gas collars | 4.00%sm_IndexPercentOfNaturalGasCollars / us-gaap_DerivativeByNatureAxis = sm_IfElPasoPermianMember |
IF HSC [Member] |  |
Derivative Financial Instruments |  |
Index percent of natural gas fixed swaps | 83.00%sm_IndexPercentOfNaturalGasFixedSwaps / us-gaap_DerivativeByNatureAxis = sm_IfHscMember |
Index percent of natural gas collars | 79.00%sm_IndexPercentOfNaturalGasCollars / us-gaap_DerivativeByNatureAxis = sm_IfHscMember |
IF NGPL TXOK [Member] |  |
Derivative Financial Instruments |  |
Index percent of natural gas fixed swaps | 1.00%sm_IndexPercentOfNaturalGasFixedSwaps / us-gaap_DerivativeByNatureAxis = sm_IfNgplTxokMember |
IF NNG Ventura [Member] |  |
Derivative Financial Instruments |  |
Index percent of natural gas fixed swaps | 3.00%sm_IndexPercentOfNaturalGasFixedSwaps / us-gaap_DerivativeByNatureAxis = sm_IfNngVenturaMember |
Index percent of natural gas collars | 7.00%sm_IndexPercentOfNaturalGasCollars / us-gaap_DerivativeByNatureAxis = sm_IfNngVenturaMember |
IF Enable East [Member] |  |
Derivative Financial Instruments |  |
Index percent of natural gas fixed swaps | 11.00%sm_IndexPercentOfNaturalGasFixedSwaps / us-gaap_DerivativeByNatureAxis = sm_IFEnableEastMember |
Index percent of natural gas collars | 10.00%sm_IndexPercentOfNaturalGasCollars / us-gaap_DerivativeByNatureAxis = sm_IFEnableEastMember |
Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 1,500,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember |
Swap | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 9,600,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 194,215,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Swap | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 1,462,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Collar [Member] | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 2,484,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Collar [Member] | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 10,478,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Second Quarter Current Year [Member] | Swap | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 1,639,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 91.26 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Second Quarter Current Year [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 15,985,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 3.90 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Second Quarter Current Year [Member] | Collar [Member] | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 709,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Floor Price | 85.00 us-gaap_DerivativeAverageFloorPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Ceiling Price | 94.06 us-gaap_DerivativeAverageCapPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Second Quarter Current Year [Member] | Collar [Member] | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 2,297,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Floor Price | 4.00 us-gaap_DerivativeAverageFloorPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Ceiling Price | 4.30 us-gaap_DerivativeAverageCapPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_SecondQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Third Quarter Current Year [Member] | Swap | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 1,254,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 90.78 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Third Quarter Current Year [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 14,950,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 4.03 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Third Quarter Current Year [Member] | Collar [Member] | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 906,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Floor Price | 85.00 us-gaap_DerivativeAverageFloorPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Ceiling Price | 91.25 us-gaap_DerivativeAverageCapPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Third Quarter Current Year [Member] | Collar [Member] | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 2,005,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Floor Price | 4.00 us-gaap_DerivativeAverageFloorPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Ceiling Price | 4.30 us-gaap_DerivativeAverageCapPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_ThirdQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Fourth Quarter Current Year [Member] | Swap | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 1,137,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 90.15 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Fourth Quarter Current Year [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 13,570,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 4.02 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Fourth Quarter Current Year [Member] | Collar [Member] | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 869,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Floor Price | 85.00 us-gaap_DerivativeAverageFloorPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Ceiling Price | 92.19 us-gaap_DerivativeAverageCapPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Fourth Quarter Current Year [Member] | Collar [Member] | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 6,176,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Floor Price | 3.97 us-gaap_DerivativeAverageFloorPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
Weighted-Average Ceiling Price | 4.30 us-gaap_DerivativeAverageCapPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_FourthQuarterCurrentYearMember / us-gaap_DerivativeInstrumentRiskAxis = sm_CollarMember |
2016 [Member] | Swap | Crude oil |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 5,570,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_A2016Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 88.01 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_CrudeOilMember / sm_DerivativeContractPeriodAxis = sm_A2016Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2016 [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 48,896,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2016Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 4.12 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2016Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2016 [Member] | Swap | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 710,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / sm_DerivativeContractPeriodAxis = sm_A2016Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 9.12 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / sm_DerivativeContractPeriodAxis = sm_A2016Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2017 [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 37,414,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2017Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 4.16 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2017Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2017 [Member] | Swap | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 542,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / sm_DerivativeContractPeriodAxis = sm_A2017Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 10.13 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / sm_DerivativeContractPeriodAxis = sm_A2017Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2018 [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 35,241,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2018Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 4.21 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2018Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2018 [Member] | Swap | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged | 210,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / sm_DerivativeContractPeriodAxis = sm_A2018Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 10.74 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / sm_DerivativeContractPeriodAxis = sm_A2018Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
2019 [Member] | Swap | Natural Gas [Member] |  |
Derivative Financial Instruments |  |
Portion of Gas Production Being Hedged | 28,159,000 sm_PortionOfGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2019Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Weighted-Average Contract Price | 4.28 us-gaap_DerivativeSwapTypeAverageFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasReservesMember / sm_DerivativeContractPeriodAxis = sm_A2019Member / us-gaap_DerivativeInstrumentRiskAxis = us-gaap_SwapMember |
Subsequent Event [Member] | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Portion of Future Oil and Gas Production Being Hedged |  | 387,000 us-gaap_PortionOfFutureOilAndGasProductionBeingHedged / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
Maximum [Member] | Subsequent Event [Member] | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Derivative, Swap Type, Fixed Price |  | 10.19 us-gaap_DerivativeSwapTypeFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
Minimum [Member] | Subsequent Event [Member] | Natural Gas Liquids |  |
Derivative Financial Instruments |  |
Derivative, Swap Type, Fixed Price |  | 9.66 us-gaap_DerivativeSwapTypeFixedPrice / us-gaap_DerivativeByNatureAxis = us-gaap_NaturalGasLiquidsReservesMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_SubsequentEventTypeAxis = us-gaap_SubsequentEventMember
Line of Credit [Member] | Revolving Credit Facility [Member] |  |
Derivative Financial Instruments |  |
Percentage of Proved Property Secured for Credit Facility Borrowing | 75.00%sm_PercentageofProvedPropertySecuredforCreditFacilityBorrowing / us-gaap_DebtInstrumentAxis = us-gaap_LineOfCreditMember / us-gaap_LongtermDebtTypeAxis = us-gaap_RevolvingCreditFacilityMember |

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- Definition The quantity of future oil and gas production being hedged. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section S99 -Paragraph 2 -Subparagraph (SAB TOPIC 12.D.3(b)) -URI http://asc.fasb.org/extlink&oid=27015634&loc=d3e516453-122869 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 12 -Section D -Paragraph b -Subsection 3 + Details
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