XML 63 R43.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Acquisitions (Details) $ / shares in Units, shares in Millions |  |  | 2 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended | 15 Months Ended
--- | --- | --- | --- | --- | --- | --- | ---
Dec. 21, 2016 USD ($) $ / shares shares | Oct. 04, 2016 USD ($) | Feb. 21, 2019 a | Sep. 30, 2018 USD ($) a | Sep. 30, 2017 USD ($) | Sep. 30, 2017 USD ($) | Dec. 31, 2018 USD ($) a $ / shares | Dec. 31, 2017 USD ($) a $ / shares | Dec. 31, 2016 USD ($) | Dec. 31, 2017 USD ($) $ / shares
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Payments to acquire oil and gas property and equipment |  |  |  |  |  |  |  | $ 33,255,000 | $ 89,896,000 | $ 2,183,790,000 |
Carrying value of properties exchanged or acquired |  |  |  |  |  |  |  | 95,121,000 |  | $ 733,000 |
Wells in progress |  |  |  |  |  |  |  | 295,529,000 | 321,347,000 |  | $ 321,347,000
Proved oil and gas properties |  |  |  |  |  |  |  | 7,278,362,000 | 6,139,379,000 |  | 6,139,379,000
Unproved oil and gas properties |  |  |  |  |  |  |  | $ 1,581,401,000 | $ 2,047,203,000 |  | $ 2,047,203,000
Common Stock, par value per share | $ / shares |  | $ 0.01 |  |  |  |  |  | $ 0.01 | $ 0.01 |  | $ 0.01
Rock Oil Acquisition 2016 [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Payments to acquire a business |  |  | $ 991,000,000 |  |  |  |  |  | $ 7,700,000 |  | $ 998,691,000
Wells in progress |  |  | 5,672,000 |  |  |  |  |  |  |  |
Proved oil and gas properties |  |  | 82,584,000 |  |  |  |  |  |  |  |
Unproved oil and gas properties |  |  | 913,819,000 |  |  |  |  |  |  |  |
Other assets |  |  | 5,338,000 |  |  |  |  |  |  |  |
Total fair value of oil and gas properties acquired |  |  | 1,007,413,000 |  |  |  |  |  |  |  |
Working capital |  |  | (1,127,000) |  |  |  |  |  |  |  |
Asset retirement obligations |  |  | (7,595,000) |  |  |  |  |  |  |  |
Total fair value of net assets acquired |  |  | $ 998,691,000 |  |  |  |  |  |  |  |
Other Martin County Acquisition 2018 [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net acres acquired | a |  |  |  |  |  |  |  | 1,030 |  |  |
Payments to acquire oil and gas property and equipment |  |  |  |  |  |  |  | $ 33,300,000 |  |  |
Other Howard and Martin Counties acquisitions 2017 [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Net acres acquired | a |  |  |  |  |  |  |  |  | 3,600 |  |
Payments to acquire oil and gas property and equipment |  |  |  |  |  |  |  |  | $ 76,500,000 |  |
QStar Acquisition 2016 [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Payments to acquire oil and gas property and equipment |  | $ 1,200,000,000 |  |  |  | $ 7,300,000 | $ 1,174,628,000 |  |  |  |
Carrying value of properties exchanged or acquired |  | 1,611,822,000 |  |  |  |  |  |  |  |  |
Wells in progress |  | 21,812,000 |  |  |  |  |  |  |  |  |
Proved oil and gas properties |  | 61,239,000 |  |  |  |  |  |  |  |  |
Unproved oil and gas properties |  | 1,538,264,000 |  |  |  |  |  |  |  |  |
Working capital |  | (1,852,000) |  |  |  |  |  |  |  |  |
Asset retirement obligations |  | $ (7,641,000) |  |  |  |  |  |  |  |  |
Private issuance of Common Stock for an acquisition | shares |  | 13.4 |  |  |  |  |  |  |  |  |
Total consideration |  |  |  |  |  |  | $ 1,611,822,000 |  |  |  |
Fair value of equity consideration | [1] | $ 437,194,000 |  |  |  |  |  |  |  |  |
Total oil and gas properties acquired |  | $ 1,621,315,000 |  |  |  |  |  |  |  |  |
Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Non-monetary trade, acreage acquired | a |  |  |  | 1,580 |  |  |  |  |  |  |
Non-monetary trade, acreage exchanged | a |  |  |  | 1,650 |  |  |  |  |  |  |
Howard and Martin Counties Trades 2018 [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Non-monetary trade, acreage acquired | a |  |  |  |  | 2,650 |  |  |  |  |  |
Carrying value of properties exchanged or acquired |  |  |  |  | $ 95,100,000 |  |  |  |  |  |
Gain (loss) recognized on trade |  |  |  |  | $ 0 |  |  |  |  |  |
Other Howard and Martin Counties trades [Member] |  |  |  |  |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |
Non-monetary trade, acreage acquired | a |  |  |  |  |  |  |  |  | 8,125 |  |
Carrying value of properties exchanged or acquired |  |  |  |  |  |  |  |  | $ 293,963,000 |  |
Non-monetary trade, acreage exchanged | a |  |  |  |  |  |  |  |  | 7,580 |  |
[1] | (1) The Company issued approximately 13.4 million shares of common stock, par value $0.01 per share, in a private placement to the sellers in the QStar Acquisition on December 21, 2016. The equity consideration was valued on this date using Level 1 and Level 2 inputs with a discount applied due to the lack of marketability in the near term in accordance with the Lock-Up and Registration Rights Agreement that prohibited the sale of such stock until no earlier than the 90th day after issuance.

X
- Definition Asset Acquisition, Consideration Transferred + References No definition available. + Details
Name: | sm_AcquisitionofOilAndGasPropertyAndEquipmentConsiderationTransferred
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Fair value of oil and gas properties acquired, net of liabilities assumed. + References No definition available. + Details
Name: | sm_FairValueofNetAssetsAcquired
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net acres acquired + References No definition available. + Details
Name: | sm_NetAcresAcquired
Namespace Prefix: | sm_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

X
- Definition Acreage acquired through non-monetary trades. + References No definition available. + Details
Name: | sm_NonmonetaryTradeAcreageAcquired
Namespace Prefix: | sm_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

X
- Definition Acreage exchanged through non-monetary trades. + References No definition available. + Details
Name: | sm_NonmonetaryTradeAcreageExchanged
Namespace Prefix: | sm_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

X
- Definition Oil and gas properties under development using the successful efforts method that are not being amortized + References No definition available. + Details
Name: | sm_WellsInProgress
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Working Capital Acquired + References No definition available. + Details
Name: | sm_WorkingCapitalAcquired
Namespace Prefix: | sm_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_AssetRetirementObligationsNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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_BusinessAcquisitionLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Face amount or stated value per share of common stock. + 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(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The fair value of assets acquired in noncash investing or financing activities. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 + Details
Name: | us-gaap_FairValueOfAssetsAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The net book value of a nonmonetary asset transferred or exchanged in connection with the acquisition of a business or asset in a noncash transaction. Noncash is defined as transactions during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. Nonmonetary assets and liabilities are assets and liabilities that will not result in cash receipts or cash payments in the future. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586 + Details
Name: | us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The value of an asset or business acquired in a noncash (or part noncash) acquisition. Noncash is defined as information about all investing and financing activities of an enterprise during a period that affect recognized assets or liabilities but that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 + Details
Name: | us-gaap_NoncashOrPartNoncashAcquisitionValueOfAssetsAcquired1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Disclosure of the difference in values (gain (loss)) between the nonmonetary assets or liabilities exchanged with another entity inclusive of boot (small monetary consideration). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 845 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=68069686&loc=d3e32049-108421 + Details
Name: | us-gaap_NonmonetaryTransactionGainLossRecognizedOnTransfer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of assets classified as other. + 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(17)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(10)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(10)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_OtherAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow to purchase long lived physical asset for use in the normal oil and gas operations and to purchase mineral interests in oil and gas properties not intended for resale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireOilAndGasPropertyAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Oil and Gas properties with proved reserves under the successful effort method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -URI http://asc.fasb.org/subtopic&trid=2145654 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=96866604&loc=d3e64746-109465 + Details
Name: | us-gaap_ProvedOilAndGasPropertySuccessfulEffortMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination. + References No definition available. + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesPurchaseOfAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of shares of stock issued during the period as part of a transaction to acquire assets that do not qualify as a business combination. + References No definition available. + Details
Name: | us-gaap_StockIssuedDuringPeriodValuePurchaseOfAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Oil and Gas properties with unproved reserves under the successful effort method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 25 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=96866604&loc=d3e64746-109465 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=68064819&loc=d3e61926-109447 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -URI http://asc.fasb.org/topic&trid=2145477 + Details
Name: | us-gaap_UnprovedOilAndGasPropertySuccessfulEffortMethod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=sm_RockOilAcquisition2016Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_PropertyAcquisitionAxis=sm_OtherMartinCountyAcquisition2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_PropertyAcquisitionAxis=sm_OtherHowardandMartinCountiesAcquisitions2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | sm_PropertyAcquisitionAxis=sm_QStarAcquisition2016Member
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_NonmonetaryTransactionTypeAxis=sm_HowardandMartinCountiesTrades2018Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_NonmonetaryTransactionTypeAxis=sm_HowardandMartinCountiesTrades2017Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |