2.2.0.25falsefalse1130 - Disclosure - Impairment of Goodwill and Long-Lived Assetstruefalsefalse1falsefalseUSDfalsefalse1/1/2010 - 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_ImpairmentOfGoodwillAndLongLivedAssetsDisclosureAbstractmwefalsenadurationNo definition available.falsefalsefalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalsefalsefalseOtherxbrli:stringItemTypestringNo definition available.falsefalseImpairment of Goodwill and Long-Lived Assets3false0mwe_ImpairmentOfGoodwillAndLongLivedAssetsDisclosureTextBlockmwefalsenadurationThis element represents the disclosure of impairment of goodwill and long-lived assets during the period.falsefalsefalsefalsefalsefalsefalsefalsefalsefalseterselabel1falsefalsefalse00<table style="font-size:10pt; font-family:'Times New Roman',times,serif;"> <tr> <td> 13. Impairment of Goodwill and Long-Lived Assets         Goodwill.    The Partnership's policy is to evaluate goodwill for impairment annually as of November 30, and whenever events or changes in circumstances indicate it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The evaluation performed as of November 30, 2010 did not indicate any impairment of goodwill.         Due to the significant decline in the market prices of crude oil and other NGLs and the continued decline in the trading price of the Partnership's common units at the end of 2008, goodwill was evaluated for impairment in 2008. As a result, the Partnership recorded impairment charges of $28.7 million to write-off the goodwill balance allocable to four of the Partnership's reporting units. Approximately $18.8 million and $9.9 million of the goodwill impairment related to the Southwest and Gulf Coast segments, respectively. The remaining goodwill balance of $9.4 million consists of $5.5 million allocated to the East Texas reporting unit in the Southwest segment and $3.9 million allocated to the Appalachia reporting unit in the Northeast segment. In completing the evaluation, management estimated the fair value of the Partnership's reporting units primarily using an income approach based on discounted future cash flows and also considered a market approach based on the Partnership's market capitalization as of December 31, 2008.         Long-Lived Assets.    The Partnership's policy is to evaluate whether there has been an impairment in the value of long-lived assets when certain events have taken place that indicate that the remaining balance may not be recoverable. The Partnership evaluates the carrying value of its property, plant and equipment and intangibles on at least a segment level and at lower levels where cash flows for specific assets can be identified.         An analysis completed during the second quarter of 2009 indicated that the future estimated operating cash flows could be at or below zero for Wirth Gathering. Wirth Gathering's expected future cash flows were adversely impacted by a significant reduction to the primary producer's drilling plan disclosed in the second quarter of 2009, as well as increased operating expenses resulting from an agreement reached in May 2009 with the non-controlling partner. The Partnership used the income approach for determining the assets' fair value and recognized an impairment of long-lived assets of approximately $5.9 million for year ended December 31, 2009. After considering the impact of the non-controlling interest, the impairment increased the net loss attributable to the Partnership for the year ended December 31, 2009 by approximately $2.9 million, before provision for income tax.         An analysis completed in 2008 indicated an impairment of the Partnership's gas-gathering assets in Manistee County, Michigan, which are part of the Partnership's Northeast segment, due to the decision to move the Fisk plant to Pennsylvania and to outsource the gas processing to a third party. The Partnership used the market approach to determine the assets' fair value and recognized an impairment of long-lived assets of $7.6 million for the year ended December 31, 2008. </td></tr></table> 13. Impairment of Goodwill and Long-Lived Assets         Goodwill.    The Partnership's policy isfalsefalsefalsefalsefalseOtherus-types:textBlockItemTypestringThis element represents the disclosure of impairment of goodwill and long-lived assets during the period.No authoritative reference available.falsefalseImpairment of Goodwill and Long-Lived Assets12Impairment of Goodwill and Long-Lived AssetsUnKnownUnKnownUnKnownUnKnownfalsetrue