Net Income Per Limited Partner Unit (Narrative) (Details) (USD $)	6 Months Ended
Jun. 30, 2011
Excess of $0.275 Per Unit [Member]
General partner incentive distribution	15.00%
Excess distribution of net income per unit	$ 0.275
Excess of $0.3125 Per Unit [Member]
General partner incentive distribution	25.00%
Excess distribution of net income per unit	$ 0.3125
Excess of $0.375 Per Unit [member]
General partner incentive distribution	50.00%
Excess distribution of net income per unit	$ 0.375

Per-share or per-unit amount of incentive dividend declared and paid to managing member or general partner.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 72
-URI http://asc.fasb.org/extlink&oid=6926462&loc=SL5163672-159010

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 55
-Paragraph 103
-URI http://asc.fasb.org/extlink&oid=6926531&loc=SL5199526-159011

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 260
-SubTopic 10
-Section 45
-Paragraph 73
-URI http://asc.fasb.org/extlink&oid=6926462&loc=SL5163674-159010

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Emerging Issues Task Force (EITF)
-Number 07-4
-Paragraph 2, 9
-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

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Namespace Prefix:	us-gaap
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration