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

Available-for-sale Security, Maturity Date at a point in time

No definition available.

Name:	atax_AvailableForSaleSecurityMaturityDateAtPointInTime
Namespace Prefix:	atax_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

The percentage of cash flows the bondholder may be entitled to if the property meets established cash flow benchmarks.

No definition available.

Name:	atax_ContingentInterestPercentage
Namespace Prefix:	atax_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Interest rate stated in the contractual debt agreement.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

Reference 2: 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

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The number of units in a real estate property owned as of the balance sheet date.

No definition available.