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This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3255-108585 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 19 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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. false2Proceeds from public equity offering, net13false 5us-gaap_ProceedsFromIssuanceOfLongTermDebtus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse10000000001000000USD$falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. 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This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Payments of long-term debt15false 5mwe_PaymentsOfPremiumsOnRedemptionOfLongTermDebtmwe_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1truefalsefalse-31500000-31500USD$falsefalsefalse2truefalsefalse-31516000-31516USD$falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryRepresents the cash outflow during the reporting period for payments of premiums on redemption of long-term debt.No definition available.false2Payments of premiums on redemption of long-term debt16false 5us-gaap_PaymentOfFinancingAndStockIssuanceCostsus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedTerseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse-14046000-14046USD$falsefalsefalse3truefalsefalse-2315000-2315USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe total of the cash outflow during the period which has been paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt and the cost incurred directly for the issuance of equity securities.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 18, 19, 20 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. 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Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3291-108585 false2Payments for debt issue costs and deferred financing costs17false 5us-gaap_ContributionsFromNoncontrollingInterestsus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00falsefalsefalse2truefalsefalse685219000685219USD$falsefalsefalse3truefalsefalse11010001101USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of cash inflow from contributions from noncontrolling interests in an investment.No definition available.false2Contribution from non-controlling interest18false 5mwe_EmployeeServiceShareBasedCompensationCashFlowEffectmwe_falsecreditdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1falsefalsefalse00falsefalsefalse2truefalsefalse-4556000-4556USD$falsefalsefalse3truefalsefalse-5841000-5841USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAggregate cash flow impact during the period related to equity instruments granted under equity-based payment arrangements. 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This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Net cash (used in) provided by operating activities30true 4us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Cash flows from investing activities:31false 5us-gaap_PaymentsToAcquirePropertyPlantAndEquipmentus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1falsefalsefalse00falsefalsefalse2truefalsefalse-480000-480USD$falsefalsefalse3truefalsefalse-114000-114USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 17 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. 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This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Net cash (used in) provided by operating activities54true 4us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstractus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Cash flows from investing activities:55false 5us-gaap_PaymentsToAcquirePropertyPlantAndEquipmentus-gaap_truecreditdurationfalsefalsefalsefalsefalsefalsefalsetruenegatedLabel1falsefalsefalse00falsefalsefalse2truefalsefalse-53319000-53319USD$falsefalsefalse3truefalsefalse-166926000-166926USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3213-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 17 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. 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