2.4.0.82410406 - Disclosure - Equity (Details Textual)truefalseIn Thousands, except Share data, unless otherwise specifiedfalse1false falsefalseD2013Q3http://www.sec.gov/CIK0001489136duration2013-07-01T00:00:002013-09-30T00:00:00sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDPUDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.semgroupcorp.com/20130630Unitsemg0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso421702false USDfalsefalse$D2013Q2http://www.sec.gov/CIK0001489136duration2013-04-01T00:00:002013-06-30T00:00:00usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDPUDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.semgroupcorp.com/20130630Unitsemg0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false falsefalseD2013Q1http://www.sec.gov/CIK0001489136duration2013-01-01T00:00:002013-03-31T00:00:004false USDfalsefalse$D2013Q2YTDhttp://www.sec.gov/CIK0001489136duration2013-01-01T00:00:002013-06-30T00:00:00sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDPUDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.semgroupcorp.com/20130630Unitsemg0USDUSD$1true 3semg_EquityLineItemssemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Equity [Line Items]2false 4us-gaap_DividendsPayableDateDeclaredDayMonthAndYearus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse002013-08-08falsefalsetrue3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:dateItemTypedateDate the dividend to be paid was declared, in CCYY-MM-DD format.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 32 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Dividends Payable, Date Declared3false 4us-gaap_CommonStockDividendsPerShareDeclaredus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse0.200.20USD$falsetruefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsenum:perShareItemTypedecimalAggregate dividends declared during the period for each share of common stock outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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=6959260&loc=d3e187085-122770 false3Common Stock, Dividends, Per Share, Declared4false 4us-gaap_DividendPayableDateToBePaidDayMonthAndYearus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse002013-08-30falsefalsetrue2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:dateItemTypedateDate the declared dividend will be paid, in CCYY-MM-DD format.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586 false0Dividends Payable, Date to be Paid5false 4semg_WarrantsExercisedDuringPeriodsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse762807762807falsefalsefalsexbrli:sharesItemTypesharesWarrants exercised during periodNo definition available.false1Warrants exercised during period6true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]7false 5us-gaap_CommonStockSharesIssuedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse4252509042525090falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse4252509042525090falsefalsefalsexbrli:sharesItemTypesharesTotal number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.Reference 1: http://www.xbrl.org/2003/role/presentationRef -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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Common stock shares issued8false 5us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumberus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse540000540000falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse540000540000falsefalsefalsexbrli:sharesItemTypesharesThe number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(b) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(a) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false1Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number9false 5semg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsPotentialyVestedsemg_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse141000141000falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse141000141000falsefalsefalsexbrli:sharesItemTypesharesShare-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Potentialy VestedNo definition available.false1Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Potenialy Vested10false 5semg_ValueofunvesteddividendrightstobesettledinClassAsharessemg_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse3900039USD$falsetruefalse3falsefalsefalse00falsefalsefalse4truefalsefalse3900039USD$falsetruefalsexbrli:monetaryItemTypemonetaryValue of unvested dividend rights to be settled in Class A sharesNo definition available.false2Deferred Compensation Liability, Classified, Noncurrent11false 5semg_NumberofClassAsharesequaltounvesteddividendrightssemg_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse717717falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse717717falsefalsefalsexbrli:sharesItemTypesharesNumber of Class A shares equal to unvested dividend rightsNo definition available.false1Number of Class A shares equal to unvested dividend rights12false 5us-gaap_StockIssuedDuringPeriodSharesNewIssuesus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse105738105738falsefalsefalsexbrli:sharesItemTypesharesNumber of new stock issued during the period.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -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=6959260&loc=d3e187085-122770 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 false1Vested common stock13false 5us-gaap_StockRepurchasedDuringPeriodSharesus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse85918591falsefalsefalsexbrli:sharesItemTypesharesNumber of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Research Bulletin (ARB) -Number 43 -Section B -Paragraph 11A -Chapter 1 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 false1Shares of vested stock awards sold back to satisfy tax obligations14false 5us-gaap_CommonStockParOrStatedValuePerShareus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse0.010.01USD$falsetruefalse3falsefalsefalse00falsefalsefalse4truefalsefalse0.010.01USD$falsetruefalsenum:perShareItemTypedecimalFace amount or stated value of common stock per share; generally not indicative of the fair market value per share.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -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 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false3Par value per share15false 5us-gaap_ClassOfWarrantOrRightOutstandingus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse13708331370833falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse13708331370833falsefalsefalsexbrli:sharesItemTypesharesAggregate amount of each class of warrants or rights outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph i -Article 4 false1Warrants issued16false 5us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRightsus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse2525falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse2525falsefalsefalseus-types:perUnitItemTypedecimalThe exercise price of each class of warrants or rights outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(4)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph i -Subparagraph 4 -Article 4 false0Price of purchase of one share of common stock against warrant17false 5semg_IncomeTaxExpenseBenefitRelatedToPostRetirementBenefitObligationsemg_falsedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse3100031USD$falsetruefalsexbrli:monetaryItemTypemonetaryIncome Tax Expense (Benefit), Related to Post Retirement Benefit ObligationNo definition available.false2Income tax expense, related to change in benefit plans18false 4us-gaap_SharePriceus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse53.8653.86USD$falsetruefalse3falsefalsefalse00falsefalsefalse4truefalsefalse53.8653.86USD$falsetruefalsenum:perShareItemTypedecimalPrice of a single share of a number of saleable stocks of a company.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 false3Share Price19false 4us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse201451201451falsefalsefalsexbrli:sharesItemTypesharesThe number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(c) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false1Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period20false 4us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValueus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse52.7852.78USD$falsetruefalsenum:perShareItemTypedecimalThe weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph c(1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 123R -Paragraph A240 -Subparagraph b(2)(c) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false3Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value21false 4us-gaap_CommonStockDividendsPerShareCashPaidus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse0.190.19USD$falsetruefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsenum:perShareItemTypedecimalAggregate dividends paid during the period for each share of common stock outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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=6959260&loc=d3e187085-122770 false3Common Stock, Dividends, Per Share, Cash Paid22false 4us-gaap_DividendsPayableDateOfRecordDayMonthAndYearus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse002013-08-19falsefalsetrue2falsefalsefalse00falsefalsefalse3falsefalsefalse002013-05-20falsefalsetrue4falsefalsefalse00falsefalsefalsexbrli:dateItemTypedateDate the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.No definition available.false0Dividends Payable, Date of Record23false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5false truefalseI2013Q2_us-gaap_ClassOfWarrantOrRightAxis_semg_WarrantsIssuedOnEmergenceDateMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseWarrants Issued On Emergence Date [Member]us-gaap_ClassOfWarrantOrRightAxisxbrldihttp://xbrl.org/2006/xbrldisemg_WarrantsIssuedOnEmergenceDateMemberus-gaap_ClassOfWarrantOrRightAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0nanafalse0Warrants Issued On Emergence Date [Member]24true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]25false 5us-gaap_ClassOfWarrantOrRightOutstandingus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse16342101634210falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse16342101634210falsefalsefalsexbrli:sharesItemTypesharesAggregate amount of each class of warrants or rights outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph i -Article 4 false1Warrants issued26false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse6false truefalseI2013Q2_us-gaap_ClassOfWarrantOrRightAxis_semg_WarrantsSubsequentlyIssuedInSettlementOfPrePetitionClaimsMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseWarrants Subsequently Issued In Settlement Of Pre-Petition Claims [Member]us-gaap_ClassOfWarrantOrRightAxisxbrldihttp://xbrl.org/2006/xbrldisemg_WarrantsSubsequentlyIssuedInSettlementOfPrePetitionClaimsMemberus-gaap_ClassOfWarrantOrRightAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0nanafalse0Warrants Subsequently Issued In Settlement Of Pre-Petition Claims [Member]27true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]28false 5us-gaap_ClassOfWarrantOrRightOutstandingus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse237897237897falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse237897237897falsefalsefalsexbrli:sharesItemTypesharesAggregate amount of each class of warrants or rights outstanding.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)) -URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph i -Article 4 false1Warrants issued29false 5semg_ClassOfWarrantOrRightToBeIssuedsemg_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse544737544737falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse544737544737falsefalsefalsexbrli:sharesItemTypesharesClass of Warrant or Right, To Be IssuedNo definition available.false1Class of Warrant or Right, To Be Issued30false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse7false USDtruefalse$I2013Q2_us-gaap_StatementClassOfStockAxis_us-gaap_CommonClassAMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseClass A [Member]us-gaap_StatementClassOfStockAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_CommonClassAMemberus-gaap_StatementClassOfStockAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$nanafalse0Class A [Member]31true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]32false 5us-gaap_CommonStockSharesAuthorizedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse9000000090000000falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse9000000090000000falsefalsefalsexbrli:sharesItemTypesharesThe maximum number of common shares permitted to be issued by an entity's charter and bylaws.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Common stock shares authorized33false 5us-gaap_CommonStockParOrStatedValuePerShareus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse0.010.01USD$falsetruefalse3falsefalsefalse00falsefalsefalse4truefalsefalse0.010.01USD$falsetruefalsenum:perShareItemTypedecimalFace amount or stated value of common stock per share; generally not indicative of the fair market value per share.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false3Par value per share34false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse8false USDtruefalse$I2013Q2_us-gaap_StatementClassOfStockAxis_us-gaap_CommonClassBMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseClass B [Member]us-gaap_StatementClassOfStockAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_CommonClassBMemberus-gaap_StatementClassOfStockAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0usdPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$nanafalse0Class B [Member]35true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]36false 5us-gaap_CommonStockSharesAuthorizedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse1000000010000000falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse1000000010000000falsefalsefalsexbrli:sharesItemTypesharesThe maximum number of common shares permitted to be issued by an entity's charter and bylaws.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Common stock shares authorized37false 5us-gaap_CommonStockParOrStatedValuePerShareus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse0.010.01USD$falsetruefalse3falsefalsefalse00falsefalsefalse4truefalsefalse0.010.01USD$falsetruefalsenum:perShareItemTypedecimalFace amount or stated value of common stock per share; generally not indicative of the fair market value per share.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -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 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false3Par value per share38false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse9false truefalseI2013Q2_us-gaap_StatementEquityComponentsAxis_semg_SharesIssuedOnEmergenceDateMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseShares Issued On Emergence Date [Member]us-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldisemg_SharesIssuedOnEmergenceDateMemberus-gaap_StatementEquityComponentsAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0nanafalse0Shares Issued On Emergence Date [Member]39true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]40false 5us-gaap_CommonStockSharesIssuedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse4088249640882496falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse4088249640882496falsefalsefalsexbrli:sharesItemTypesharesTotal number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.Reference 1: http://www.xbrl.org/2003/role/presentationRef -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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Common stock shares issued41false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse10false truefalseI2013Q2_us-gaap_StatementEquityComponentsAxis_semg_SharesSubsequentlyIssuedInSettlementOfPrePetitionClaimsMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseShares Subsequently Issued In Settlement Of Pre-Petition Claims [Member]us-gaap_StatementEquityComponentsAxisxbrldihttp://xbrl.org/2006/xbrldisemg_SharesSubsequentlyIssuedInSettlementOfPrePetitionClaimsMemberus-gaap_StatementEquityComponentsAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0nanafalse0Shares Subsequently Issued In Settlement Of Pre-Petition Claims [Member]42true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]43false 5us-gaap_CommonStockSharesIssuedus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse226016226016falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse226016226016falsefalsefalsexbrli:sharesItemTypesharesTotal number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.Reference 1: http://www.xbrl.org/2003/role/presentationRef -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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 30 -Article 5 false1Common stock shares issued44false 5semg_SharesToBeIssuedToSettlePrepetitionClaimssemg_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse517500517500falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse517500517500falsefalsefalsexbrli:sharesItemTypesharesShares To Be Issued TO Settle Prepetition ClaimsNo definition available.false1Shares To Be Issued To Settle Prepetition Claims45false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse11false truefalseD2013Q2YTD_us-gaap_InstrumentAxis_us-gaap_WarrantMemberhttp://www.sec.gov/CIK0001489136duration2013-01-01T00:00:002013-06-30T00:00:00falsefalseWarrant [Member]us-gaap_InstrumentAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_WarrantMemberus-gaap_InstrumentAxisexplicitMembersharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0nanafalse0Warrant [Member]46true 3semg_EquityLineItemssemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Equity [Line Items]47false 4us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecuritiesus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse420067420067falsefalsefalsexbrli:sharesItemTypesharesNumber of shares issued during the period as a result of the conversion of convertible securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 12 -Paragraph 10 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -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=6959260&loc=d3e187085-122770 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4, 5 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 7: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 8: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29-30) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false1Stock Issued During Period, Shares, Conversion of Convertible Securities48false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse12false truefalseI2013Q2_us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_semg_SemcrudePipelineMemberhttp://www.sec.gov/CIK0001489136instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseSemcrude Pipeline [Member]us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxisxbrldihttp://xbrl.org/2006/xbrldisemg_SemcrudePipelineMemberus-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxisexplicitMembernumberStandardhttp://www.xbrl.org/2003/instancepurexbrli0nanafalse0Semcrude Pipeline [Member]49true 3semg_EquityLineItemssemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Equity [Line Items]50false 4us-gaap_EquityMethodInvestmentOwnershipPercentageus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truetruefalse0.330.33falsefalsefalse3falsefalsefalse00falsefalsefalse4truetruefalse0.330.33falsefalsefalsenum:percentItemTypepureThe percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 159 -Paragraph 18 -Subparagraph f -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=6382943&loc=d3e33918-111571 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 18 -Paragraph 20 -Subparagraph a (1) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false0Equity Method Investment, Ownership Percentage51false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse13false truefalseD2013Q2_us-gaap_PlanNameAxis_us-gaap_EmployeeStockMemberhttp://www.sec.gov/CIK0001489136duration2013-04-01T00:00:002013-06-30T00:00:00falsefalseEmployee Stock [Member]us-gaap_PlanNameAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_EmployeeStockMemberus-gaap_PlanNameAxisexplicitMembernumberStandardhttp://www.xbrl.org/2003/instancepurexbrli0sharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0nanafalse0Employee Stock [Member]52true 4semg_EquityTextualAbstractsemg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0EQUITY (Textual) [Abstract]53false 4semg_Limitationonsharesperparticipantperofferingperiodsemg_falsenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse1250012500falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse1250012500falsefalsefalsexbrli:sharesItemTypesharesLimitation on shares per participant per offering periodNo definition available.false1Compensation and Employee Benefit Plans [Text Block]54false 4us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardDiscountFromMarketPricePurchaseDateus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truetruefalse0.850.85falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalsenum:percentItemTypepureThe discount rate from market value on purchase date that participants pay for shares.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 false0Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date55false 4us-gaap_CommonStockCapitalSharesReservedForFutureIssuanceus-gaap_truenainstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse10000001000000falsefalsefalse3falsefalsefalse00falsefalsefalse4truefalsefalse10000001000000falsefalsefalsexbrli:sharesItemTypesharesAggregate number of common shares reserved for future issuance.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -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 false1Common Stock, Capital Shares Reserved for Future IssuancefalseEquity (Details Textual) (USD $)ThousandsNoRoundingNoRoundingUnKnowntruefalsefalseSheethttp://www.semgroupcorp.com/role/EquityDetailsTextual455