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           Commitments and Contingencies (Details) (USD $)
  
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        0 Months Ended | 
        1 Months Ended | 
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           Dec. 09, 2010
 
          lender 
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           Mar. 31, 2012
 
          claim 
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           Mar. 31, 2015 
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           Dec. 31, 2014 
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           Mar. 31, 2014 
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           Feb. 14, 2014 
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           Dec. 31, 2013 
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           Jul. 17, 2013 
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           Jul. 08, 2013 
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           Jun. 17, 2013 
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           Jun. 06, 2011 
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           Dec. 31, 2008
 
          action 
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           Oct. 26, 2011
 
          JointVenture 
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        | Loss Contingencies [Line Items] | 
         
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        | Reserved for litigation and asserted claims | 
         
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$ 15,109,000us-gaap_LitigationReserve
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$ 16,499,000us-gaap_LitigationReserve
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        | Warranty reserve | 
         
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21,839,000us-gaap_StandardProductWarrantyAccrual
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22,080,000us-gaap_StandardProductWarrantyAccrual
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21,482,000us-gaap_StandardProductWarrantyAccrual
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21,971,000us-gaap_StandardProductWarrantyAccrual
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        | Loss Contingency, Pending Claims, Number | 
         
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2us-gaap_LossContingencyPendingClaimsNumber
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        | Number of lenders filing petition for involuntary bankruptcy | 
        
3mth_NumberOfLendersFilingPetitionForInvoluntaryBankruptcy
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        | Initial Litigation Judgment Amount | 
         
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15,053,857mth_InitialLitigationJudgmentAmount
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        | Litigation Judgment Amount With Interest | 
         
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15,753,344mth_LitigationJudgmentAmountWithInterest
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        | Litigation Judgment Interest | 
         
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699,487mth_LitigationJudgmentInterest
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        | Supersedeas Bond | 
         
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16,930,477mth_SupersedeasBond
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16,050,604mth_SupersedeasBond
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        | Incremental Attorney Fees to Supersedeas Bond | 
         
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877,241mth_IncrementalAttorneyFeestoSupersedeasBond
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        | Amount requested in demand for arbitration related to alleged breaches | 
         
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13,500,000us-gaap_LossContingencyDamagesSoughtValue
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        | Additional amount requested in demand for arbitration related to pro rata future infrastructure improvement costs | 
         
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9,800,000mth_FutureInfrastructureImprovementCosts
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        | South Edge Guarantee [Member] | 
         
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        | Loss Contingencies [Line Items] | 
         
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        | Loss Contingency, Pending Claims, Number | 
         
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2us-gaap_LossContingencyPendingClaimsNumber / us-gaap_GuaranteeObligationsByNatureAxis = mth_SouthEdgeGuaranteeMember
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        | Equity Method Investment, Ownership Percentage | 
         
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3.53%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_GuaranteeObligationsByNatureAxis = mth_SouthEdgeGuaranteeMember
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        | Springing Repayment Guarantee Original Demand Letter | 
         
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$ 13,200,000mth_SpringingRepaymentGuaranteeOriginalDemandLetter / us-gaap_GuaranteeObligationsByNatureAxis = mth_SouthEdgeGuaranteeMember
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        | South Edge [Member] | 
         
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        | Loss Contingencies [Line Items] | 
         
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        | Number of co-ventures in joint venture | 
         
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4mth_NumberOfCoVenturesInJointVenture / us-gaap_LossContingenciesByNatureOfContingencyAxis = mth_SouthEdgeMember
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