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           Senior and Convertible Senior Notes (Details Textual) (Senior Notes [Member], USD $) 
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           Mar. 31, 2015 
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           Dec. 31, 2014 
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| 4.50% senior notes due 2018 [Member] | ||
| Debt Instrument [Line Items] | ||
| Debt instrument, stated rate | 
4.50%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_SeniorNotesDueTwoThousandEighteenMemberDomain / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
        
4.50%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_SeniorNotesDueTwoThousandEighteenMemberDomain / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
      
| 7.15% senior notes due 2020 [Member] | ||
| Debt Instrument [Line Items] | ||
| Debt instrument, stated rate | 
7.15%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_SeniorNotesDueTwoThousandTwentyMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
        
7.15%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_SeniorNotesDueTwoThousandTwentyMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
      
| 7.00% senior notes due 2022 [Member] | ||
| Debt Instrument [Line Items] | ||
| Debt instrument, stated rate | 
7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_SeniorNotesDueTwoThousandTwentyTwoMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
        
7.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_SeniorNotesDueTwoThousandTwentyTwoMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
      
| 1.875% convertible senior notes due 2032 [Member] | ||
| Debt Instrument [Line Items] | ||
| Debt instrument, stated rate | 
1.875%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_ConvertibleSeniorNotesDueTwoThousandThirtyTwoMemberMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
        
1.875%us-gaap_DebtInstrumentInterestRateStatedPercentage / us-gaap_DebtInstrumentAxis = mth_ConvertibleSeniorNotesDueTwoThousandThirtyTwoMemberMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
      
| Debt instrument, convertible, conversion price | 
 58.14us-gaap_DebtInstrumentConvertibleConversionPrice1 / us-gaap_DebtInstrumentAxis = mth_ConvertibleSeniorNotesDueTwoThousandThirtyTwoMemberMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
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| Conversion premium | 
47.50%mth_ConversionPremium / us-gaap_DebtInstrumentAxis = mth_ConvertibleSeniorNotesDueTwoThousandThirtyTwoMemberMember / us-gaap_LongtermDebtTypeAxis = us-gaap_SeniorNotesMember  | 
        
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- Definition 
          Initial conversion premium of the convertible notes based on the closing price of the common stock on the transaction closing date. No definition available. 
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- Definition 
          The price per share of the conversion feature embedded in the debt instrument. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Contractual interest rate for funds borrowed, under the debt agreement. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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