The 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Condensed Consolidating Guarantor Financial Statements Condensed Consolidating Guarantor Financial Statements (Details Textual) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Jun. 14, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Senior Notes	$ 300,000	$ 300,000	$ 0
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	100.00%
Senior Notes [Member]
Condensed Financial Statements, Captions [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.50%
Semcrude Pipeline [Member]
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	33.00%