Equity (Details 2) (Common units)	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Oct. 03, 2011 Osterman	Mar. 31, 2012 Osterman	Mar. 31, 2012 SemStream	Nov. 01, 2011 SemStream	Jan. 03, 2012 Pacer	Mar. 31, 2012 Pacer	Mar. 31, 2013 High Sierra	Mar. 31, 2013 Retail propane	Mar. 31, 2013 Water services	Nov. 12, 2012 Pecos	Mar. 31, 2013 Pecos	Jan. 11, 2013 Third Coast	Mar. 31, 2013 Third Coast
Common Units Issued in Business Combinations
Common units issued	24,250,258	14,432,031	4,000,000	4,000,000	8,932,031	8,932,031	1,500,000	1,500,000	20,703,510	850,676	516,978	1,834,414	1,834,414	344,680	344,680

Number of shares of equity interests issued or issuable to acquire entity.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration