Annual report pursuant to Section 13 and 15(d)

Business and Summary of Significant Accounting Policies (Details Textual)

v2.4.1.9
Business and Summary of Significant Accounting Policies (Details Textual) (USD $)
 12 Months Ended 3 Months Ended
Dec. 31, 2014
State
Region
Community
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2014
Organization and Presentation [Line Items]        
Liquid Investment Maturity Period To Be Classified As Cash Equivalent Maximum 3 months      
Entity operations in number of regions 3mth_EntityOperationsInNumberOfRegions     3mth_EntityOperationsInNumberOfRegions
Number of states in regions 9us-gaap_NumberOfStatesInWhichEntityOperates     9us-gaap_NumberOfStatesInWhichEntityOperates
Number of communities in which homes are sold 229mth_NumberofCommunitiesinWhichHomesareSold     229mth_NumberofCommunitiesinWhichHomesareSold
Amounts in transit from title companies for home closings $ 59,200,000mth_AmountsInTransitFromTitleCompaniesForHomeClosings $ 26,400,000mth_AmountsInTransitFromTitleCompaniesForHomeClosings   $ 59,200,000mth_AmountsInTransitFromTitleCompaniesForHomeClosings
Money Market Funds, at Carrying Value 200,000us-gaap_MoneyMarketFundsAtCarryingValue 68,300,000us-gaap_MoneyMarketFundsAtCarryingValue   200,000us-gaap_MoneyMarketFundsAtCarryingValue
Other than Temporary Impairment Losses, Investments, Portion Recognized in Earnings, Net, Held-to-maturity Securities 0us-gaap_OtherThanTemporaryImpairmentLossesInvestmentsPortionRecognizedInEarningsNetHeldtomaturitySecurities      
Held-to-maturity Securities 0us-gaap_HeldToMaturitySecurities 89,529,000us-gaap_HeldToMaturitySecurities   0us-gaap_HeldToMaturitySecurities
Deposits on real estate under option or contract 94,989,000us-gaap_DepositAssets 51,595,000us-gaap_DepositAssets   94,989,000us-gaap_DepositAssets
Deferred costs representing debt issuance costs, net 10,100,000us-gaap_DeferredFinanceCostsNet 12,200,000us-gaap_DeferredFinanceCostsNet   10,100,000us-gaap_DeferredFinanceCostsNet
Accumulated amortization of debt issuance costs 13,400,000us-gaap_AccumulatedAmortizationDeferredFinanceCosts 11,200,000us-gaap_AccumulatedAmortizationDeferredFinanceCosts   13,400,000us-gaap_AccumulatedAmortizationDeferredFinanceCosts
Advertising expense 11,800,000us-gaap_AdvertisingExpense 7,800,000us-gaap_AdvertisingExpense 5,500,000us-gaap_AdvertisingExpense  
Contribution to the 401(K) Retirement Plan 1,900,000us-gaap_DefinedContributionPlanCostRecognized 1,300,000us-gaap_DefinedContributionPlanCostRecognized 1,000,000us-gaap_DefinedContributionPlanCostRecognized  
Adjustment to warranty reserve balance 500,000us-gaap_StandardProductWarrantyAccrualPreexistingIncreaseDecrease 1,311,000us-gaap_StandardProductWarrantyAccrualPreexistingIncreaseDecrease    
Minimum [Member]        
Organization and Presentation [Line Items]        
Base price per house for sale range       130,000mth_BasePricePerHouseForSaleRange
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
Investment Maturity Period 3 months      
Community life cycle range 3 years      
Property and equipment useful life 3 years      
Warranty period following home closings 1 year      
Maximum [Member]        
Organization and Presentation [Line Items]        
Base price per house for sale range       $ 1,230,000mth_BasePricePerHouseForSaleRange
/ us-gaap_RangeAxis
= us-gaap_MaximumMember
Investment Maturity Period 18 months      
Community life cycle range 5 years      
Property and equipment useful life 7 years      
Warranty period following home closings 10 years