Certain provisions of the partnership agreement 3 (Textuals) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013
Partners' Capital Notes [Abstract]
Deferred Tax Liabilities Investments Decrease	$ 2.5
Adjustments To Additional Paid In Capital Reallocation Of Minority Interest	$ 8.9

Change in additional paid in capital as a result of a reallocation of a subsidiary's stockholders' equity to noncontrolling interest due to the subsidiary issuing stock. This reallocation is from a capital transaction.

Reference 1: 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 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

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration