Transactions with Related Parties Transactions with Related Parties Narrative (Details)	1 Months Ended	3 Months Ended
Feb. 28, 2017 USD ($)	Mar. 31, 2017 USD ($) Property	Mar. 31, 2016 USD ($)
Rate for administration fees		0.45%
Fees and commissions, other		$ 938,000	$ 388,000
Management fees revenue		$ 244,000	312,000
MF Properties Managed [Member]
Number of Real Estate Properties \| Property		7
Majority-Owned Subsidiary, Unconsolidated [Member]
Payment for administrative fees		$ 865,000	687,000
Affiliated Entity [Member]
Payment for administrative fees		15,000	19,000
Farnam Capital Advisors, LLC [Member]
Placement advisory fees		269,000	194,000
Farnam Capital Advisors, LLC [Member] \| Term A/B Trust [Member]
Consulting fees	$ 921,000	$ 921,000	$ 0

Consulting fees.

No definition available.

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

- Definition

Consulting fees related to the placement and continued performance monitoring of mortgage revenue bond purchases.

+ References

No definition available.

+ Details

Name:	atax_PlacementAdvisoryFees
Namespace Prefix:	atax_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Rate for administration fees - rate charged on the bonds and loans collateralized by the underlying properties for administration of the assets

+ References

No definition available.

+ Details

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Namespace Prefix:	atax_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of fee and commission revenue classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13)
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Revenue, comprised of base and incentive revenue derived from the management of joint ventures, managing third-party properties, or another entity's operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The number of real estate properties 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
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- Definition

Amount paid to managing member or general partner, affiliate of managing member or general partner, or affiliate of limited liability company (LLC) or limited partnership (LP) for administrative services provided to the LLC or LP, for example, but not limited to, salaries, rent, or overhead costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 850
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864

+ Details

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Data Type:	xbrli:monetaryItemType
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- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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- Details

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