XML 49 R37.htm IDEA: XBRL DOCUMENT
v3.4.0.3

Derivative Financial Instruments (Details) | May. 04, 2016 MMBTU $ / EnergyContent $ / Barrels bbl | Mar. 31, 2016 MMBTU $ / EnergyContent $ / Barrels bbl | Jan. 14, 2016 MMBTU $ / EnergyContent
--- | --- | --- | ---
NYMEX Oil Swap Contract Second Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 1,752,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 86.73 |
NYMEX Oil Swap Contract Third Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 1,840,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 71.80 |
NYMEX Oil Swap Contract Fourth Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 1,399,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 67.73 |
NYMEX Oil Swap Contract 2017 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 2,035,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 44.84 |
NYMEX Oil Swap Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 7,026,000 |
Gas Swaps Contract Second Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | 0 |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 20,780,000 |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  | 3.40 |
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent |  | 0.00 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 20,780,000 |
Gas Swaps Contract Third Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | 0 |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 18,830,000 |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  | 3.38 |
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent |  | 0.00 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 18,830,000 |
Gas Swaps Contract Fourth Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | 0 |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 18,988,000 |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  | 3.69 |
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent |  | 0.00 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 18,988,000 |
Gas Swaps Contract 2017 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | 0 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes | MMBTU |  |  | 38,600,000
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 85,019,000 |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  | 4.09 | 4.43
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent |  | 0.00 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 85,019,000 |
Gas Swaps Contract 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | (30,606,000) |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 30,606,000 |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  | 4.27 |
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent |  | 4.27 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 0 |
Gas Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | (24,415,000) |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 24,415,000 |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent |  | 4.34 |
Derivative, Swap Type, Average Fixed Price, Purchased Volumes | $ / EnergyContent |  | 4.34 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 0 |
Gas Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure, Purchased Volumes | MMBTU |  | (55,021,000) |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU |  | 198,638,000 |
Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes | MMBTU |  | 143,617,000 |
IF El Paso Permian [Member] |  |  |
Derivative Financial Instruments |  |  |
Index percent of natural gas fixed swaps |  | 2.00% |
IF HSC [Member] |  |  |
Derivative Financial Instruments |  |  |
Index percent of natural gas fixed swaps |  | 97.00% |
IF NNG Ventura [Member] |  |  |
Derivative Financial Instruments |  |  |
Index percent of natural gas fixed swaps |  | 1.00% |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Second Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 828,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 8.28 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Third Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 751,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 8.70 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract Fourth Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 687,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 8.71 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2017 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 3,062,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 8.92 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 2,435,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 10.18 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 1,200,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 10.92 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 539,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 11.13 |
OPIS Ethane Purity Mont Belvieu [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 9,502,000 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 949,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 19.64 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 863,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 19.03 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 792,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 18.53 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2017 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Propane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 2,604,000 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 208,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 24.02 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 186,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 21.86 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 170,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 21.86 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2017 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Normal Butane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 564,000 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Second Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 174,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 24.68 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Third Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 155,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 22.42 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract Fourth Quarter 2016 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 141,000 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 22.42 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2017 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2018 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2019 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contract 2020 [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 0 |
Derivative, Swap Type, Average Fixed Price | $ / Barrels |  | 0.00 |
OPIS Isobutane Mont Belvieu Non-TET [Member] | NGL Swaps Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume |  | 470,000 |
Subsequent Event [Member] | NYMEX Oil Collar Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | 2,668,000 |  |
Subsequent Event [Member] | NYMEX Oil Swap Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Volume | 1,018,000 |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent | 47.15 |  |
Subsequent Event [Member] | Gas Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU | 37,900,000 |  |
Minimum [Member] | Subsequent Event [Member] | NYMEX Oil Collar Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Floor Price | $ / Barrels | 40.00 |  |
Derivative, Cap Price | $ / Barrels | 50.35 |  |
Minimum [Member] | Subsequent Event [Member] | Gas Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent | 2.36 |  |
Maximum [Member] | Subsequent Event [Member] | NYMEX Oil Collar Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Floor Price | $ / Barrels | 45.00 |  |
Derivative, Cap Price | $ / Barrels | 52.85 |  |
Maximum [Member] | Subsequent Event [Member] | Gas Contracts [Member] |  |  |
Derivative Financial Instruments |  |  |
Derivative, Swap Type, Average Fixed Price | $ / EnergyContent | 3.19 |  |

X
- Definition Derivative, Nonmonetary Notional Amount, Energy Measure, Net of Purchased Volumes + References No definition available. + Details
Name: | sm_DerivativeNonmonetaryNotionalAmountEnergyMeasureNetofPurchasedVolumes
Namespace Prefix: | sm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal energy measure used to calculate payments on a derivative instrument for purchased fixed price volumes + References No definition available. + Details
Name: | sm_DerivativeNonmonetaryNotionalAmountEnergyMeasurePurchasedVolumes
Namespace Prefix: | sm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Derivative, Nonmonetary Notional Amount, Energy Measure, Sold Volumes + References No definition available. + Details
Name: | sm_DerivativeNonmonetaryNotionalAmountEnergyMeasureSoldVolumes
Namespace Prefix: | sm_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Derivative, Swap Type, Average Fixed Price, Purchased Volumes + References No definition available. + Details
Name: | sm_DerivativeSwapTypeAverageFixedPricePurchasedVolumes
Namespace Prefix: | sm_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Index percent of natural gas fixed swaps + References No definition available. + Details
Name: | sm_IndexPercentOfNaturalGasFixedSwaps
Namespace Prefix: | sm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cap rate on a price risk derivative such as a cap or collar. A payment or receipt is triggered if the market rate exceeds the cap rate on the contract. + References No definition available. + Details
Name: | us-gaap_DerivativeCapPrice
Namespace Prefix: | us-gaap_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Floor rate on a price risk derivative such as a floor or a collar. A payment or receipt is triggered if the market rate falls below the floor rate on the contract. + References No definition available. + Details
Name: | us-gaap_DerivativeFloorPrice
Namespace Prefix: | us-gaap_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal energy measure used to calculate payments on a derivative instrument. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountEnergyMeasure
Namespace Prefix: | us-gaap_
Data Type: | num:energyItemType
Balance Type: | na
Period Type: | duration

X
- Definition Nominal volume used to calculate payments on a derivative instrument. + References No definition available. + Details
Name: | us-gaap_DerivativeNonmonetaryNotionalAmountVolume
Namespace Prefix: | us-gaap_
Data Type: | num:volumeItemType
Balance Type: | na
Period Type: | duration

X
- Definition Average fixed price related to the group of price risk swap derivatives. + References No definition available. + Details
Name: | us-gaap_DerivativeSwapTypeAverageFixedPrice
Namespace Prefix: | us-gaap_
Data Type: | us-types:perUnitItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NYMEXOilSwapContractSecondQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NYMEXOilSwapContractThirdQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NYMEXOilSwapContractFourthQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NYMEXOilSwapContract2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NYMEXOilSwapContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContractSecondQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContractThirdQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContractFourthQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContract2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContract2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContract2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasSwapsContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_IfElPasoPermianMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_IfHscMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_IfNngVenturaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_OPISEthanePurityMontBelvieuMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContractSecondQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContractThirdQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContractFourthQuarter2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContract2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContract2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContract2019Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContract2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NGLSwapsContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_OPISPropaneMontBelvieuNonTETMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_OPISNormalButaneMontBelvieuNonTETMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_DerivativeUnderlyingIndexAxis=sm_OPISIsobutaneMontBelvieuNonTETMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_NYMEXOilCollarContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=sm_GasContractsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |