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Subsequent Events (Details) $ in Millions | Feb. 01, 2018 USD ($)
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Mortgages | Subsequent Event [Member] | Highlands of West Village [Member] |
Subsequent Event [Line Items] |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate | $ 38.5

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- Definition Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 310 -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-29(Column G)) -URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014 + Details
Name: | us-gaap_MortgageLoansOnRealEstate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | us-gaap_DebtInstrumentAxis=us-gaap_MortgagesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | dei_LegalEntityAxis=maa_HighlandsofWestVillageMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |