Annual report pursuant to Section 13 and 15(d)

Related Party Transactions (Details Textual)

v2.4.1.9
Related Party Transactions (Details Textual) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Payments to Aviation Charter [Member]      
Related Party Transaction [Line Items]      
Related Party Transaction, Amounts of Transaction $ 211,000us-gaap_RelatedPartyTransactionAmountsOfTransaction
/ us-gaap_RelatedPartyTransactionAxis
= mth_PaymentstoAviationCharterMember 		$ 359,000us-gaap_RelatedPartyTransactionAmountsOfTransaction
/ us-gaap_RelatedPartyTransactionAxis
= mth_PaymentstoAviationCharterMember 		$ 330,000us-gaap_RelatedPartyTransactionAmountsOfTransaction
/ us-gaap_RelatedPartyTransactionAxis
= mth_PaymentstoAviationCharterMember
Alliance Bank [Member]      
Related Party Transaction [Line Items]      
Interest income on cash deposits placed with affiliated entity 430,000us-gaap_InterestIncomeRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember 		654,000us-gaap_InterestIncomeRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember 		687,000us-gaap_InterestIncomeRelatedParty
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember
Alliance Bank [Member] | Affiliate Entity, a Custodian of CDARS [Member]      
Related Party Transaction [Line Items]      
Cash deposits with related party 9,995mth_CashDepositsWithRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= mth_AffiliateEntityCustodianOfCdarsMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember 		89,500,000mth_CashDepositsWithRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= mth_AffiliateEntityCustodianOfCdarsMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember 		 
Alliance Bank [Member] | Affiliate Entity, a Custodian of ICS [Member]      
Related Party Transaction [Line Items]      
Cash deposits with related party $ 907mth_CashDepositsWithRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= mth_AffiliateEntityCustodianOfIcsMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember 		$ 157,500,000mth_CashDepositsWithRelatedParty
/ us-gaap_RelatedPartyTransactionAxis
= mth_AffiliateEntityCustodianOfIcsMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= mth_AllianceBankMember