Investments in Mortgage Revenue Bonds - Term of Mortgage Revenue Bond After Restructuring (Details) - Series B [Member] - Houston, Texas [Member]	12 Months Ended
Dec. 31, 2016 Unit	Aug. 31, 2016 USD ($)
Concord at Gulfgate [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Restructured	August
Units (Unaudited) \| Unit	288
Maturity Date	Mar. 01, 2032
Base Interest Rate	12.00%
Principal Outstanding at Date of Restructuring \| $		$ 2,125,000
Concord at Little York [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Restructured	August
Units (Unaudited) \| Unit	276
Maturity Date	Mar. 01, 2032
Base Interest Rate	12.00%
Principal Outstanding at Date of Restructuring \| $		960,000
Concord at Williamcrest [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Restructured	August
Units (Unaudited) \| Unit	288
Maturity Date	Mar. 01, 2032
Base Interest Rate	12.00%
Principal Outstanding at Date of Restructuring \| $		$ 2,800,000

Investment owned, restructured month.

No definition available.

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Namespace Prefix:	atax_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Mortgage loans on real estate, restructuring, face amount.

+ References

No definition available.

+ Details

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

- Definition

Stated maturity date of the mortgage loan receivable on real estate, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

The stated interest rate on the mortgage loan receivable or the weighted average interest rate on a group of loans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29)
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 10
-Section S99
-Paragraph 6
-Subparagraph (SX 210.5-04.(c) Schedule IV)
-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Details

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- Details

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- Details

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- Details

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- Details

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