Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=34725769&loc=d3e28878-108400

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-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- 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.

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- Definition

The amount of debt discount that was originally recognized at the issuance of the instrument that has yet to be amortized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
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Balance Type:	debit
Period Type:	instant

- Definition

Amount of interest capitalized during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Allowance for Funds Used during Construction
-URI http://asc.fasb.org/extlink&oid=6504829

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391

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Period Type:	duration

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.8)
-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.16)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Subparagraph (SX 210.7-03.16)
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 19, 20, 22
-Article 5

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- Definition

The effective interest rate at the end of the reporting period.

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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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Balance Type:	na
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- 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

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Balance Type:
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- Details

Name:	us-gaap_LongtermDebtTypeAxis=semg_EurodollarRateBorrowingsMember
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Long-Term Debt (Details Textual)	3 Months Ended
Long-Term Debt (Details Textual)	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2016 MXN	Dec. 31, 2015 USD ($)	May. 14, 2015 USD ($)
Debt Instrument [Line Items]
Interest Costs Capitalized	$ 800,000	$ 300,000
Corporate, Non-Segment [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	300,000,000
Corporate, Non-Segment [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Interest Expense, Debt	$ 5,800,000	5,800,000
Debt Instrument, Interest Rate, Stated Percentage	7.50%		7.50%
Corporate, Non-Segment [Member] \| Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	$ 5,300,000
Corporate, Non-Segment [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest Expense, Debt	1,400,000	1,000,000
Maximum borrowing capacity	500,000,000
Borrowings outstanding	$ 70,000,000			$ 30,000,000
Corporate, Non-Segment [Member] \| Revolving Credit Facility [Member] \| Alternate Base Rate Borrowings [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	4.50%		4.50%
Borrowings outstanding	$ 40,000,000
Corporate, Non-Segment [Member] \| Revolving Credit Facility [Member] \| Eurodollar Rate Borrowings [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	2.62%		2.62%
Borrowings outstanding	$ 30,000,000
Corporate [Member] \| Letter of Credit [Member]
Debt Instrument [Line Items]
Interest rate in effect	2.00%		2.00%
SemMexico [Member]
Debt Instrument [Line Items]
Borrowings outstanding	$ 0			0
SemMexico [Member] \| Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	$ 17,000,000		MXN 292,800,000
Interest rate in effect	0.25%		0.25%
SemMexico [Member] \| 100 million MXP facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 5,800,000		MXN 100,000,000
Borrowings outstanding	0
Rose Rock Midstream, L.P. [Member] \| Bilateral Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	$ 33,500,000
Interest rate in effect	1.75%		1.75%
Rose Rock Midstream, L.P. [Member] \| Letter of Credit [Member]
Debt Instrument [Line Items]
Letters of credit outstanding	$ 33,400,000
Interest rate in effect	2.50%		2.50%
Rose Rock Midstream, L.P. [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest Expense, Debt	$ 1,500,000	2,300,000
Borrowings outstanding	$ 24,000,000			0
Rose Rock Midstream, L.P. [Member] \| Revolving Credit Facility [Member] \| Alternate Base Rate Borrowings [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	5.00%		5.00%
Maximum borrowing capacity	$ 585,000,000
Rose Rock Midstream, L.P. [Member] \| Rose Rock Notes due 2022 [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount	400,000,000
Rose Rock Midstream, L.P. [Member] \| Rose Rock Notes due 2022 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Interest Expense, Debt	$ 5,900,000	$ 5,800,000
Debt Instrument, Interest Rate, Stated Percentage	5.625%		5.625%
Rose Rock Midstream, L.P. [Member] \| Rose Rock Notes due 2023 [Member]
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount	$ 5,317,000			$ 5,455,000
Rose Rock Midstream, L.P. [Member] \| Rose Rock Notes due 2023 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Interest Expense, Debt	$ 5,200,000
Debt Instrument, Face Amount					$ 350,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.625%		5.625%
Mexican bank prime rate [Member] \| SemMexico [Member] \| 100 million MXP facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Fair Value, Inputs, Level 1 [Member] \| Corporate, Non-Segment [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value	$ 242,000,000
Fair Value, Inputs, Level 1 [Member] \| Rose Rock Midstream, L.P. [Member] \| Rose Rock Notes due 2022 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value	270,000,000
Fair Value, Inputs, Level 1 [Member] \| Rose Rock Midstream, L.P. [Member] \| Rose Rock Notes due 2023 [Member] \| Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Fair Value	$ 228,000,000