Name:	atax_AvailableForSaleSecuritiesAtParValue
Namespace Prefix:	atax_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Maturity of mortgage revenue bonds acquired.

No definition available.

Name:	atax_MaturityOfMortgageRevenueBondsAcquired
Namespace Prefix:	atax_
Data Type:	xbrli:dateItemType
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Period Type:	duration

Contractual interest rate for funds borrowed, under the debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Data Type:	num:percentItemType
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The number of units in a real estate property owned as of the balance sheet date.

No definition available.

Name:	us-gaap_NumberOfUnitsInRealEstateProperty
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Data Type:	xbrli:integerItemType
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	na
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Name:	dei_EntityByLocationAxis=atax_AvistarAtWoodHollowMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	dei_EntityByLocationAxis=atax_AvistarAtCopperfieldMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	dei_EntityByLocationAxis=atax_AvistarAtWilcrestMember
Namespace Prefix:
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