XML 87 R65.htm IDEA: XBRL DOCUMENT
v3.20.4

Fair Value Measurements (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands |  | 12 Months Ended |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Jun. 17, 2020 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Aug. 20, 2018 | Sep. 12, 2016 | Aug. 12, 2016 | May 21, 2015 | Nov. 17, 2014 | May 20, 2013
Assets: |  |  |  |  |  |  |  |  |  |
Derivative Assets, Fair Value, Gross Asset |  | $ 54,353 | $ 75,808 |  |  |  |  |  |  |
Liabilities: |  |  |  |  |  |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability |  | (222,520) | (54,290) |  |  |  |  |  |  |
Oil and Gas Properties |  |  |  |  |  |  |  |  |  |
Impairment of proved oil and gas properties and related support equipment |  | 956,700 | 0 | $ 0 |  |  |  |  |  |
Abandonment and impairment of unproved properties |  | 59,300 | 33,800 | 49,900 |  |  |  |  |  |
Impairment |  | 1,016,013 | 33,842 | $ 49,889 |  |  |  |  |  |
Property, Plant, and Equipment, Fair Value Disclosure |  | 0 | 0 |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Class of Warrant or Right, Number of Securities Called by Warrants or Rights | 5,900 |  |  |  |  |  |  |  |  |
Warrants Percent of Outstanding Stock | 5.00% |  |  |  |  |  |  |  |  |
Exercise price of warrants | $ 0.01 |  |  |  |  |  |  |  |  |
Warrant triggering date - amount | $ 1,000,000 |  |  |  |  |  |  |  |  |
Issuance of warrants | 21,500 | $ 21,520 |  |  |  |  |  |  |  |
1.50% Senior Secured Convertible Notes Due 2021 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  | 1.50% |  |  |  |  |  |  |  |
Principal amount |  | $ 65,485 | 0 |  |  |  |  |  |  |
Fair value |  | $ 61,449 | 0 |  |  |  |  |  |  |
10.0% Senior Secured Notes due 2025 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  | 10.00% |  |  |  |  |  |  |  |
Principal amount | $ 446,700 | $ 446,675 | 0 |  |  |  |  |  |  |
Fair value |  | $ 482,887 | $ 0 |  |  |  |  |  |  |
6.125% Senior Unsecured Notes Due 2022 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage | 6.125% | 6.125% | 6.125% |  |  |  |  |  | 6.125% |
Principal amount |  | $ 212,403 | $ 476,796 |  |  |  |  |  | $ 600,000 |
Fair value |  | $ 205,379 | $ 481,564 |  |  |  |  |  |  |
5.0% Senior Unsecured Notes Due 2024 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage | 5.00% | 5.00% | 5.00% |  |  |  |  |  |  | 5.00%
Principal amount |  | $ 277,034 | $ 500,000 |  |  |  |  |  |  | $ 500,000
Fair value |  | $ 240,072 | $ 479,815 |  |  |  |  |  |  |
5.625% Senior Unsecured Notes Due 2025 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage | 5.625% | 5.625% | 5.625% |  |  |  |  | 5.625% |  |
Principal amount |  | $ 349,118 | $ 500,000 |  |  |  |  | $ 500,000 |  |
Fair value |  | $ 289,401 | $ 475,835 |  |  |  |  |  |  |
6.75% Senior Unsecured Notes Due 2026 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage | 6.75% | 6.75% | 6.75% |  |  | 6.75% |  |  |  |
Principal amount |  | $ 419,235 | $ 500,000 |  |  | $ 500,000 |  |  |  |
Fair value |  | $ 342,385 | $ 494,860 |  |  |  |  |  |  |
6.625% Senior Unsecured Notes Due 2027 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage | 6.625% | 6.625% | 6.625% |  | 6.625% |  |  |  |  |
Principal amount |  | $ 416,791 | $ 500,000 |  | $ 500,000 |  |  |  |  |
Fair value |  | $ 331,220 | $ 493,750 |  |  |  |  |  |  |
1.50% Senior Unsecured Convertible Notes Due 2021 [Member] |  |  |  |  |  |  |  |  |  |
Debt Instrument, Fair Value Disclosure [Abstract] |  |  |  |  |  |  |  |  |  |
Senior Notes, interest rate, stated percentage |  | 1.50% | 1.50% |  |  |  |  |  |  |
Principal amount |  | $ 0 | $ 172,500 |  |  |  | $ 172,500 |  |  |
Fair value |  | $ 0 | 164,430 |  |  |  |  |  |  |
Fair Value, Nonrecurring [Member] | Measurement Input, Discount Rate [Member] | Oil and Gas Properties [Member] |  |  |  |  |  |  |  |  |  |
Oil and Gas Properties |  |  |  |  |  |  |  |  |  |
Fair value assumptions, measurement input |  | 0.11 |  |  |  |  |  |  |  |
Not Designated as Hedging Instrument [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] |  |  |  |  |  |  |  |  |  |
Assets: |  |  |  |  |  |  |  |  |  |
Derivative Assets, Fair Value, Gross Asset |  | $ 0 | 0 |  |  |  |  |  |  |
Liabilities: |  |  |  |  |  |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability |  | 0 | 0 |  |  |  |  |  |  |
Not Designated as Hedging Instrument [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] |  |  |  |  |  |  |  |  |  |
Assets: |  |  |  |  |  |  |  |  |  |
Derivative Assets, Fair Value, Gross Asset |  | 54,353 | 75,808 |  |  |  |  |  |  |
Liabilities: |  |  |  |  |  |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability |  | 222,520 | 54,290 |  |  |  |  |  |  |
Not Designated as Hedging Instrument [Member] | Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |  |  |  |  |
Assets: |  |  |  |  |  |  |  |  |  |
Derivative Assets, Fair Value, Gross Asset |  | 0 | 0 |  |  |  |  |  |  |
Liabilities: |  |  |  |  |  |  |  |  |  |
Derivative Liability, Fair Value, Gross Liability |  | $ 0 | $ 0 |  |  |  |  |  |  |

X
- Definition Assumption used in valuing an instrument. + References No definition available. + Details
Name: | sm_FairValueAssumptionsMeasurementInput
Namespace Prefix: | sm_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition The impairment expense recorded to reduce the value of proved oil and gas assets. + References No definition available. + Details
Name: | sm_ImpairmentofProvedOilandGasProperties
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Accumulated expirations or loss on unproved oil and gas properties. + References No definition available. + Details
Name: | sm_ImpairmentofUnprovedOilandGasProperties
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | sm_OilAndGasPropertiesAbstract
Namespace Prefix: | sm_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Warrant Triggering Date - Amount + References No definition available. + Details
Name: | sm_WarrantTriggeringDateAmount
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Warrants Percent of Outstanding Stock + References No definition available. + Details
Name: | sm_WarrantsPercentOfOutstandingStock
Namespace Prefix: | sm_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of increase in additional paid in capital (APIC) resulting from the issuance of warrants. Includes allocation of proceeds of debt securities issued with detachable stock purchase warrants. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 25 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109126253&loc=d3e4724-112606 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770 + Details
Name: | us-gaap_AdjustmentsToAdditionalPaidInCapitalWarrantIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_AssetsFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Face (par) amount of debt instrument at time of issuance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DebtInstrumentFairValueDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2921-110230 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=66906256&loc=d3e66150-109466 + Details
Name: | us-gaap_ImpairmentOfOilAndGasProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LiabilitiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
Name: | us-gaap_LongTermDebtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value portion of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_PropertyPlantAndEquipmentFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A150SeniorSecuredConvertibleNotesDue2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A100SeniorSecuredNotesDue2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A6125SeniorUnsecuredNotesDue2022Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A50SeniorUnsecuredNotesDue2024Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A5625SeniorUnsecuredNotesDue2025Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A675SeniorUnsecuredNotesDue2026Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A6625SeniorUnsecuredNotesDue2027Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=sm_A150SeniorUnsecuredConvertibleNotesDue2021Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsNonrecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MeasurementInputTypeAxis=us-gaap_MeasurementInputDiscountRateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_OilAndGasPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_NondesignatedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |