2.4.0.82102100 - Disclosure - Basis of Presentationtruefalsefalse1falsefalsefalseD2013Q2YTDhttp://www.sec.gov/CIK0001407463duration2013-01-01T00:00:002013-06-30T00:00:001true1us-gaap_AccountingPoliciesAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse02false2us-gaap_BasisOfPresentationAndSignificantAccountingPoliciesTextBlockus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00<div style="font-family:Times New Roman;font-size:10pt;"><div style="line-height:120%;padding-top:12px;text-align:justify;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-weight:bold;">Basis of Presentation</font></div><div style="line-height:120%;padding-top:12px;text-align:justify;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;">Presentation.</font><font style="font-family:inherit;font-size:10pt;"> In the opinion of management, the consolidated financial statements of the Partnership as of </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">June 30, 2013</font><font style="font-family:inherit;font-size:10pt;">, and for the </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">three and six months ended</font><font style="font-family:inherit;font-size:10pt;"> </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">June 30, 2013</font><font style="font-family:inherit;font-size:10pt;"> and </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">2012</font><font style="font-family:inherit;font-size:10pt;">, include all adjustments and accruals, consisting only of normal recurring accrual adjustments, which are necessary for a fair presentation of the results for the interim periods. These interim results are not necessarily indicative of results for a full year.</font></div><div style="line-height:120%;padding-top:12px;text-align:justify;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">Certain information and footnote disclosures normally included in financial statements prepared in accordance with generally accepted accounting principles in the United States ("GAAP") have been condensed in or omitted from this report pursuant to the rules and regulations of the United States Securities and Exchange Commission (the "SEC"). These consolidated financial statements should be read together with the consolidated financial statements and notes thereto included in the Partnership's Annual Report on Form 10-K for the year ended </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">December 31, 2012</font><font style="font-family:inherit;font-size:10pt;">.</font></div><div style="line-height:120%;padding-top:12px;text-align:justify;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;font-style:italic;">Common unit purchase proposal from Pioneer.</font><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;"> </font><font style="font-family:inherit;font-size:10pt;">On May 7, 2013, Pioneer delivered a proposal to the chairman of the Conflicts Committee (the "Conflicts Committee") of the General Partner to acquire all of the outstanding common units of the Partnership held by unitholders other than Pioneer or its subsidiaries for consideration of </font><font style="font-family:Times New Roman;font-size:10pt;color:#000000;text-decoration:none;">0.2234</font><font style="font-family:inherit;font-size:10pt;"> of a share of common stock of Pioneer for each outstanding common unit of the Partnership held by such unitholders in a transaction to be structured as a merger of the Partnership with a wholly-owned subsidiary of  Pioneer.  Pioneer's proposal was made based on the assumption that the Partnership would declare and pay the distribution for the period April 1, 2013 to June 30, 2013 (which was declared in July 2013 and is to be paid on August 9, 2013, to unitholders of record on August 2, 2013) and then suspend future common unit distributions pending the execution of a definitive agreement and the consummation of a transaction.  The proposal was referred to the Conflicts Committee, which is reviewing and evaluating the proposal. The consummation of the transaction contemplated by Pioneer's proposal is subject to approval of Pioneer's Board of Directors, approval of the Conflicts Committee and the Board of Directors of the General Partner and the negotiation of a definitive agreement.  There can be no assurance that a definitive agreement will be executed or that any transaction will be approved or consummated.</font></div><div style="line-height:120%;padding-top:12px;text-align:justify;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;color:#000000;font-style:italic;font-weight:bold;text-decoration:none;">Net income</font><font style="font-family:inherit;font-size:10pt;font-style:italic;font-weight:bold;"> per common unit.</font><font style="font-family:inherit;font-size:10pt;"> </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">Net income</font><font style="font-family:inherit;font-size:10pt;"> per common unit is calculated by dividing the limited partners' interest in </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">net income</font><font style="font-family:inherit;font-size:10pt;"> (which excludes net income allocable to unvested participating securities) by the weighted average number of common units outstanding.</font></div><div style="line-height:120%;padding-top:12px;text-align:justify;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The Partnership applies the provisions of Accounting Standards Codification ("ASC") Topic 260 "Earnings Per Share" when determining </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">net income</font><font style="font-family:inherit;font-size:10pt;"> per common unit. Instruments granted in unit-based payment transactions that are determined to be participating securities prior to vesting are included in the </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">net income</font><font style="font-family:inherit;font-size:10pt;"> allocation in computing basic and diluted </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">net income</font><font style="font-family:inherit;font-size:10pt;"> per unit under the two-class method. Participating securities represent unvested unit-based compensation awards that have non-forfeitable distribution rights during their vesting periods, such as the phantom units and restricted units awarded under the Pioneer Southwest Energy Partners L.P. 2008 Long Term Incentive Plan (the "LTIP").</font></div><div style="line-height:120%;padding-top:12px;text-align:justify;text-indent:32px;font-size:10pt;"><font style="font-family:inherit;font-size:10pt;">The Partnership's </font><font style="font-family:inherit;font-size:10pt;color:#000000;text-decoration:none;">net income</font><font style="font-family:inherit;font-size:10pt;"> is allocated to partners' equity accounts in accordance with the provisions of the First Amended and Restated Agreement of Limited Partnership of Pioneer Southwest Energy Partners L.P. (the "Partnership Agreement").</font></div></div>falsefalsefalsenonnum:textBlockItemTypenaThe entire disclosure for the basis of presentation and significant accounting policies concepts. Basis of presentation describes the underlying basis used to prepare the financial statements (for example, US Generally Accepted Accounting Principles, Other Comprehensive Basis of Accounting, IFRS). Accounting policies describe all significant accounting policies of the reporting entity.No definition available.false0falseBasis of PresentationUnKnownUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.pioneersouthwest.com/role/BasisOfPresentation12