2.2.0.25falsefalse1030 - Disclosure - Redemption and Mergertruefalsefalse1falsefalseUSDfalsefalse1/1/2010 - 12/31/2010 USD ($) USD ($) / shares $D2010http://www.sec.gov/CIK0001166036duration2010-01-01T00:00:002010-12-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170SharesStandardhttp://www.xbrl.org/2003/instancesharesxbrli0USDPerShareDividehttp://www.xbrl.org/2003/iso4217USDiso4217http://www.xbrl.org/2003/instancesharesxbrli0USDUSD$2true0mwe_RedemptionAndMergerDisclosureAbstractmwefalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseRedemption and Merger3false0mwe_RedemptionAndMergerTextBlockmwefalsenadurationThis element represents the disclosure of redemption and merger completed during the period covered by this report.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td> 3. Redemption and Merger         On February 21, 2008, the Partnership completed the transactions contemplated by its plan of redemption and merger with the Corporation and MWEP, L.L.C., a wholly-owned subsidiary of the Partnership. Under the Merger, the shareholders of the Corporation exchanged each share of Corporation common stock for consideration equal to 1.9051 Partnership common units ("Exchange Ratio"). This Exchange Ratio was computed based on the stated consideration of 1.285 Partnership common units plus $20 in cash, or equivalent value. Contemporaneously with the closing of the transactions contemplated by the Merger, the Partnership separately acquired 100% of the Class B membership interests in the General Partner that had been held by current and former management and certain directors of the Corporation and the General Partner under the Participation Plan in exchange for approximately $21.5 million in cash and approximately 0.9 million common units valued at $30.1 million. Using the Exchange Ratio, the number of Corporation shares outstanding as of December 31, 2007 and activity through February 21, 2008 has been adjusted to the equivalent number of Partnership common units in the accompanying Consolidated Financial Statements. The following table illustrates these conversions (shares and units in thousands): <div style="PADDING-RIGHT: 0pt; PADDING-LEFT: 0pt; PADDING-BOTTOM: 0pt; MARGIN-LEFT: 10%; WIDTH: 80%; PADDING-TOP: 0pt; POSITION: relative">   <div align="center"> <table cellspacing="0" cellpadding="0" width="100%" border="0"> <tr style="HEIGHT: 0px"> <td style="FONT-FAMILY: times" align="left"></td> <td style="FONT-FAMILY: times" width="12"></td> <td style="FONT-FAMILY: times" align="right" width="7"></td> <td style="FONT-FAMILY: times" width="49"></td> <td style="FONT-FAMILY: times" width="12"></td> <td style="FONT-FAMILY: times" align="right" width="7"></td> <td style="FONT-FAMILY: times" width="46"></td> <td style="FONT-FAMILY: times" width="12"></td> <td style="FONT-FAMILY: times" align="right" width="7"></td> <td style="FONT-FAMILY: times" width="44"></td> <td style="FONT-FAMILY: times" width="12"></td></tr> <tr style="HEIGHT: 0px" valign="bottom"> <th style="FONT-FAMILY: times" align="left">  </th> <th style="FONT-FAMILY: times"> </th> <th style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" align="center" colspan="2">Common Shares </th> <th style="FONT-FAMILY: times"> </th> <th style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" align="center" colspan="2">Exchange Ratio </th> <th style="FONT-FAMILY: times"> </th> <th style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" align="center" colspan="2">Common Units </th> <th style="FONT-FAMILY: times"> </th></tr> <tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"> <td style="FONT-FAMILY: times"> Shares of Corporation Common Stock Outstanding at December 31, 2007</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">11,999.8</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">1.9051</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">22,861</td> <td style="FONT-FAMILY: times"> </td></tr> <tr style="HEIGHT: 0px" valign="bottom" bgcolor="white"> <td style="FONT-FAMILY: times"> Stock Option exercises in first quarter 2008, prior to Merger</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">51.5</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">1.9051</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">98</td> <td style="FONT-FAMILY: times"> </td></tr> <tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"> <td style="FONT-FAMILY: times"> Conversion of Restricted Shares to Partnership Phantom units</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">(23.8</td> <td style="FONT-FAMILY: times">)</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">1.9051</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">(45</td> <td style="FONT-FAMILY: times">)</td></tr> <tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top"> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom" align="right"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td></tr> <tr style="HEIGHT: 0px" valign="bottom" bgcolor="white"> <td style="FONT-FAMILY: times"> Shares eligible for redemption or conversion to Partnership Units</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">12,027.5</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">22,914</td> <td style="FONT-FAMILY: times"> </td></tr> <tr style="HEIGHT: 0px" valign="bottom" bgcolor="#CCEEFF"> <td style="FONT-FAMILY: times"> Common shares tendered for redemption in cash</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">(3,914.5</td> <td style="FONT-FAMILY: times">)</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">1.9051</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">(7,458</td> <td style="FONT-FAMILY: times">)</td></tr> <tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top"> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom" align="right"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 1pt solid; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td></tr> <tr style="HEIGHT: 0px" valign="bottom" bgcolor="white"> <td style="FONT-FAMILY: times"> Common shares tendered for conversion to Partnership common units</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">8,113.0</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">1.9051</td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times"> </td> <td style="FONT-FAMILY: times" align="right">15,456</td> <td style="FONT-FAMILY: times"> </td></tr> <tr style="FONT-SIZE: 1.5pt; HEIGHT: 0px" valign="top"> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 2.25pt double; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="FONT-FAMILY: times" valign="bottom" align="right"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td> <td style="BORDER-BOTTOM: #000000 2.25pt double; FONT-FAMILY: times" valign="bottom" align="right" colspan="2"> </td> <td style="FONT-FAMILY: times" valign="bottom"> </td></tr></table></div> </div>         In connection with the Merger, the incentive distribution rights in the Partnership, the 2% economic interest in the Partnership held by MarkWest Energy GP, L.L.C. (the "General Partner") and the Partnership common units owned by the Corporation were exchanged for Partnership Class A units. Class A units represent limited partner interests in the Partnership and have identical rights and obligations of the Partnership common units except that Class A units (a) do not have the right to vote on, approve or disapprove, or otherwise consent to or not consent to any matter (including mergers, share exchanges and similar statutory authorizations) except as otherwise required by any non-waivable provision of law and (b) do not share in any cash and cash equivalents on hand, income, gains, losses, deductions and credits that are derived from or attributable to the Partnership's ownership of, or sale or disposition of, the shares of MarkWest Hydrocarbon common stock. The Class A units held by the Corporation and the General Partner are not treated as outstanding common units in the Consolidated Balance Sheets.</td></tr></table> 3. Redemption and Merger         On February 21, 2008, the Partnership completed the transactions contemplated byfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis element represents the disclosure of redemption and merger completed during the period covered by this report.No authoritative reference available.falsefalseRedemption and Merger12Redemption and MergerUnKnownUnKnownUnKnownUnKnownfalsetrue