Subsequent Events (Details) (Subsequent events, USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended
Jul. 31, 2013
Subsequent events
Distribution to common unitholders (in dollars per unit)	$ 0.35
Expected total distribution	$ 12.3
Maximum
Subsequent events
Common units authorized under DRIP (in units)	7,500,000

Amount of cash or stock or unit payment to LLC member or LP limited partner after the end of an accounting 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-Subparagraph (SAB TOPIC 4.F)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187171-122770

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration