<?xml version="1.0" encoding="us-ascii"?><InstanceReport xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><Version>2.4.0.8</Version><ReportLongName>2114100 - Disclosure - Series A Preferred Units</ReportLongName><DisplayLabelColumn>true</DisplayLabelColumn><ShowElementNames>false</ShowElementNames><RoundingOption /><HasEmbeddedReports>false</HasEmbeddedReports><Columns><Column FlagID="0"><Id>1</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

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</LabelSeparator><Level>1</Level><ElementName>us-gaap_TemporaryEquityDisclosureAbstract</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText /><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>xbrli:stringItemType</ElementDataType><SimpleDataType>string</SimpleDataType><IsTotalLabel>false</IsTotalLabel><UnitID>0</UnitID><Label>Temporary Equity Disclosure [Abstract]</Label></Row><Row FlagID="0"><Id>2</Id><IsAbstractGroupTitle>false</IsAbstractGroupTitle><LabelSeparator>

</LabelSeparator><Level>2</Level><ElementName>us-gaap_TemporaryEquityTableTextBlock</ElementName><ElementPrefix>us-gaap_</ElementPrefix><IsBaseElement>true</IsBaseElement><BalanceType>na</BalanceType><PeriodType>duration</PeriodType><IsReportTitle>false</IsReportTitle><IsSegmentTitle>false</IsSegmentTitle><IsCalendarTitle>false</IsCalendarTitle><IsEquityPrevioslyReportedAsRow>false</IsEquityPrevioslyReportedAsRow><IsEquityAdjustmentRow>false</IsEquityAdjustmentRow><IsBeginningBalance>false</IsBeginningBalance><IsEndingBalance>false</IsEndingBalance><IsReverseSign>false</IsReverseSign><PreferredLabelRole>terseLabel</PreferredLabelRole><FootnoteIndexer /><Cells><Cell FlagID="0" ContextID="D2012Q4" UnitID=""><Id>1</Id><IsNumeric>false</IsNumeric><IsRatio>false</IsRatio><DisplayZeroAsNone>false</DisplayZeroAsNone><NumericAmount>0</NumericAmount><RoundedNumericAmount>0</RoundedNumericAmount><NonNumbericText>&lt;div style="font-family:Times New Roman;font-size:10pt;"&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;font-weight:bold;"&gt;Series A Preferred Units&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;On September&amp;#160;2, 2009, the Partnership issued &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;4,371,586&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; Series A Preferred Units at a price of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$18.30&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per unit, less issuance costs and a &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;4%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; discount of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$3 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for net proceeds of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$77 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, exclusive of the General Partner&amp;#8217;s contribution of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$2 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;. The Series A Preferred Units are convertible to common units under terms described below, and if outstanding, are mandatorily redeemable on &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;September 2, 2029&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; for &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$80 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; plus all accrued but unpaid distributions thereon (the &amp;#8220;Series A Liquidation Value&amp;#8221;) and accrued interest. The Series A Preferred Units receive fixed quarterly cash distributions of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$0.445&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per unit which began with the quarter ending March&amp;#160;31, 2010.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Distributions on the Series A Preferred Units were accrued for the first two quarters (and not paid in cash) and will result in an increase in the number of common units issuable upon conversion. If on any distribution payment date beginning March&amp;#160;31, 2010, the Partnership (1)&amp;#160;fails to pay distributions on the Series A Preferred Units, (2)&amp;#160;reduces the distributions on the common units to zero and (3)&amp;#160;is prohibited by its material financing agreements from paying cash distributions, such distributions shall automatically accrue and accumulate until paid in cash. If the Partnership has failed to pay cash distributions in full for two quarters (whether or not consecutive) from and including the quarter ended on March&amp;#160;31, 2010, then if the Partnership fails to pay cash distributions on the Series A Preferred Units, all future distributions on the Series A Preferred Units that are accrued rather than being paid in cash by the Partnership will consist of the following: (1)&amp;#160;&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$0.35375&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per Series A Preferred Unit per quarter, (2)&amp;#160;&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$0.09125&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per Series A Preferred Unit per quarter (the &amp;#8220;Common Unit Distribution Amount&amp;#8221;), payable solely in common units, and (3)&amp;#160;&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$0.09125&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per Series A Preferred Unit per quarter (the &amp;#8220;PIK Distribution Additional Amount&amp;#8221;), payable solely in common units. The total number of common units payable in connection with the Common Unit Distribution Amount or the PIK Distribution Additional Amount cannot exceed &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$2 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; in any period of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;20&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; consecutive fiscal quarters. &lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Upon the Partnership&amp;#8217;s breach of certain covenants (a &amp;#8220;Covenant Default&amp;#8221;), the holders of the Series A Preferred Units will be entitled to an increase of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$0.1825&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per quarterly distribution, payable solely in common units (the &amp;#8220;Covenant Default Additional Amount&amp;#8221;). All accumulated and unpaid distributions will accrue interest (i)&amp;#160;at a rate of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2.432%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per quarter, or (ii)&amp;#160;if the Partnership has failed to pay all PIK Distribution Additional Amounts or Covenant Default Additional Amounts or any Covenant Default has occurred and is continuing, at a rate of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;3.429%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; per quarter while such failure to pay or such Covenant Default continues.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The Series A Preferred Units are convertible, at the holder&amp;#8217;s option, into common units, provided that the holder must request conversion of at least &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;375,000&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; Series A Preferred Units. The conversion price will initially be &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$18.30&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, subject to adjustment for customary events (such as unit splits). The number of common units issuable is equal to the issue price of the Series A Preferred Units (i.e. &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$18.30&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;) being converted plus all accrued but unpaid distributions and accrued but unpaid interest thereon (the &amp;#8220;Redeemable Face Amount&amp;#8221;), divided by the applicable conversion price.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Commencing on September&amp;#160;2, 2014, if at any time the volume-weighted average trading price of the common units over the trailing 20-trading day period (the &amp;#8220;VWAP Price&amp;#8221;) is less than the then-applicable conversion price, the conversion ratio will be increased to: the quotient of (1)&amp;#160;the Redeemable Face Amount on the date that the holder&amp;#8217;s conversion notice is delivered, divided by (2)&amp;#160;the product of (x)&amp;#160;the VWAP Price set forth in the applicable conversion notice and (y)&amp;#160;&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;91%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, but will not be less than &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$10&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Also commencing on September&amp;#160;2, 2014, the Partnership will have the right at any time to convert all or part of the Series A Preferred Units into common units, if (1)&amp;#160;the daily volume-weighted average trading price of the common units is greater than &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;150%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of the then-applicable conversion price for &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;20&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;out of the trailing &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;30&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;trading days, and (2)&amp;#160;certain minimum public float and trading volume requirements are satisfied.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In the event of a change of control, the Partnership will be required to make an offer to the holders of the Series A Preferred Units to purchase their Series A Preferred Units for an amount equal to &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;101%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of their Series A Liquidation Value. In addition, in the event of certain business combinations or other transactions involving the Partnership in which the holders of common units receive cash consideration exclusively in exchange for their common units (a &amp;#8220;Cash Event&amp;#8221;), the Partnership must use commercially reasonable efforts to ensure that the holders of the Series A Preferred Units will be entitled to receive a security issued by the surviving entity in the Cash Event with comparable powers, preferences and rights to the Series A Preferred Units. If the Partnership is unable to ensure that the holders of the Series A Preferred Units will be entitled to receive such a security, then the Partnership will be required to make an offer to the holders of the Series A Preferred Units to purchase their Series A Preferred Units for an amount equal to &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;120%&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; of their Series A Liquidation Value. If the Partnership enters into any recapitalization, reorganization, consolidation, merger, spin-off that is not a Cash Event, the Partnership will make appropriate provisions to ensure that the holders of the Series A Preferred Units receive a security with comparable powers, preferences and rights to the Series A Preferred Units upon consummation of such transaction. Subsequent to the ETE Acquisition, no unitholder exercised this option.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Holders may elect to convert Series A Preferred Units to common units at any time. As of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;December&amp;#160;31, 2012&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;, the Series A Preferred Units were convertible to &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;4,658,700&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; common units.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;The following table provides a reconciliation of the beginning and ending balances of the Series A Preferred Units for all income statement periods presented. The amount includes the accretion to redemption value of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;$80 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; plus any accrued and unpaid distributions and accrued interest by deducting amounts from partners&amp;#8217; capital over the remaining periods until the mandatory redemption date of &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;September 2, 2029&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;.&lt;/font&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:8px;padding-top:8px;text-align:center;font-size:10pt;"&gt;&lt;div style="padding-left:0px;text-indent:0px;line-height:normal;padding-top:10px;"&gt;&lt;table cellpadding="0" cellspacing="0" style="font-family:Times New Roman;font-size:10pt;margin-left:auto;margin-right:auto;width:100%;border-collapse:collapse;text-align:left;"&gt;&lt;tr&gt;&lt;td colspan="7" rowspan="1"&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td width="71%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="13%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="12%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;td width="1%" rowspan="1" colspan="1"&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;border-bottom:2px solid #000000;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:center;font-size:8pt;"&gt;&lt;font style="font-family:inherit;font-size:8pt;font-weight:bold;"&gt;Units&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="3" style="vertical-align:bottom;border-bottom:2px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1"&gt;&lt;div style="text-align:center;font-size:8pt;"&gt;&lt;font style="font-family:inherit;font-size:8pt;font-weight:bold;"&gt;Amount&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Balance at January 1, 2011&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;4,371,586&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;$&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;71&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Accretion to redemption value&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#8212;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;border-bottom:1px solid #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#8212;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Balance at December 31, 2011&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;4,371,586&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;71&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Accretion to redemption value&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#8212;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td colspan="2" style="vertical-align:bottom;padding-left:2px;padding-top:2px;padding-bottom:2px;" rowspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;2&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;tr&gt;&lt;td style="vertical-align:top;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;Balance at December 31, 2012&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:3px double #000000;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;4,371,586&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:3px double #000000;background-color:#cceeff;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;background-color:#cceeff;padding-left:2px;padding-top:2px;padding-bottom:2px;padding-right:2px;" rowspan="1" colspan="1"&gt;&lt;div style="overflow:hidden;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&amp;#160;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:3px double #000000;padding-left:2px;padding-top:2px;padding-bottom:2px;background-color:#cceeff;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;$&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:3px double #000000;background-color:#cceeff;padding-top:2px;padding-bottom:2px;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:right;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;73&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;td style="vertical-align:bottom;border-bottom:3px double #000000;background-color:#cceeff;border-top:1px solid #000000;" rowspan="1" colspan="1"&gt;&lt;div style="text-align:left;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;&lt;br clear="none"/&gt;&lt;/font&gt;&lt;/div&gt;&lt;/td&gt;&lt;/tr&gt;&lt;/table&gt;&lt;/div&gt;&lt;/div&gt;&lt;div style="line-height:120%;padding-bottom:12px;text-align:justify;font-size:10pt;"&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;In July 2013, the Partnership was notified by two of the Series A Preferred Units holders of their election to convert their Series A Preferred Units to common units; these holders owned &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2.4 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt; Series A Preferred Units.  The total number of common units they will receive is &lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;"&gt;2.6 million&lt;/font&gt;&lt;font style="font-family:inherit;font-size:10pt;"&gt;.&lt;/font&gt;&lt;/div&gt;&lt;/div&gt;</NonNumbericText><FootnoteIndexer /><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat></Cell></Cells><ElementDataType>nonnum:textBlockItemType</ElementDataType><SimpleDataType>na</SimpleDataType><ElementDefenition>Tabular disclosure of temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.</ElementDefenition><ElementReferences>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 SEC

 -Name Regulation S-X (SX)

 -Number 210

 -Section 08

 -Paragraph d

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

 -Publisher SEC

 -Name Regulation S-X (SX)

 -Number 210

 -Section 02

 -Paragraph 28

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Emerging Issues Task Force (EITF)

 -Number D-98

 -Paragraph 2,4,5,6

 -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 5: http://www.xbrl.org/2003/role/presentationRef

 -Publisher FASB

 -Name Statement of Financial Accounting Standard (FAS)

 -Number 129

 -Paragraph 2,3,4,5,6,7,8

 -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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