2.2.0.25falsefalse1020 - Disclosure - Recent Accounting Pronouncementstruefalsefalse1falsefalseUSDfalsefalse1/1/2011 - 3/31/2011 USD ($) USD ($) / shares $D2011Q1http://www.sec.gov/CIK0001166036duration2011-01-01T00:00:002011-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0mwe_RecentAccountingPronouncementsDisclosureAbstractmwefalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseRecent Accounting Pronouncements3false0us-gaap_ScheduleOfNewAccountingPronouncementsAndChangesInAccountingPrinciplesTextBlockus-gaaptruenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td> 2. Recent Accounting Pronouncements         In September 2009, the FASB amended the accounting guidance for revenue recognition for multiple-deliverable arrangements. The amended guidance establishes a hierarchy for determining the selling price of each individual deliverable and eliminates the residual value method of allocating the selling price. The amended guidance was effective for the Partnership prospectively for all revenue arrangements entered into or materially modified on or after January 1, 2011. The amendment did not have a material effect on the Partnership's condensed consolidated financial statements. </td></tr></table> 2. Recent Accounting Pronouncements         In September 2009, the FASB amended the accounting guidance for revenuefalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringRepresents disclosure of any changes in an accounting principle, including a change from one generally accepted accounting principle to another generally accepted accounting principle when there are two or more generally accepted accounting principles that apply or when the accounting principle formerly used is no longer generally accepted. Also disclose any change in the method of applying an accounting principle, or any change in an accounting principle required by a new pronouncement in the unusual instance that a new pronouncement does not include specific transition provisions.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 154 -Paragraph 2, 17, 18 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 28 -Paragraph 23, 24 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 01 -Paragraph b -Subparagraph 6 -Article 10 falsefalseRecent Accounting Pronouncements12Recent Accounting PronouncementsUnKnownUnKnownUnKnownUnKnownfalsetrue