Transactions with Related Parties Narrative Tagging (Details) (USD $)	3 Months Ended
Mar. 31, 2015 properties	Mar. 31, 2014
rate for administration fees	0.45%atax_RateForAdministrationFees
Fees and Commissions, Other	$ 534,000us-gaap_FeesAndCommissionsOther	$ 323,000us-gaap_FeesAndCommissionsOther
Management Fees Revenue	324,000us-gaap_ManagementFeesRevenue	300,000us-gaap_ManagementFeesRevenue
Placement Advisory Fees	267,000atax_PlacementAdvisoryFees	161,500atax_PlacementAdvisoryFees
Number of Variable Interest Entities	11atax_NumberOfVariableInterestEntities
Majority-Owned Subsidiary, Unconsolidated [Member]
Payment for Administrative Fees	620,000	473,000
Affiliated Entity [Member]
Payment for Administrative Fees	16,500	17,000
Consolidated VIEs [Member]
Number of Real Estate Properties	2
Number of Variable Interest Entities	2
MF Properties [Member]
Number of Real Estate Properties	6
UNL Project [Member]
Fees and Commissions	$ 0	$ 112,000
Total Owners [Member]
Number of Owners	4
Total Owners [Member] \| Consolidated VIEs [Member]
Number of Variable Interest Entities	2
Unconsolidated Properties [Member]
Number of Variable Interest Entities	9

Number of owners of the consolidated VIE's.

No definition available.

Name:	atax_NumberOfOwners
Namespace Prefix:	atax_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of variable interest entities owned.

+ References

No definition available.

+ Details

Name:	atax_NumberOfVariableInterestEntities
Namespace Prefix:	atax_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- 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 collaterized by the underlying properties for adminstration of the assets

+ References

No definition available.

+ Details

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

- Definition

Amount of fees and commissions from financial services and banking activities and correspondent clearing. Includes fees from depositor accounts, credit cards, merchant discounts, and fiduciary and trust activities, guarantee fees, investment advisory, management, and administrative fees, transfer agent fees, and insurance commissions.

+ 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 13

-Article 9

+ Details

Name:	us-gaap_FeesAndCommissions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fee and commission revenue earned from sources not otherwise specified in the existing taxonomy.

+ References

+ Details

Name:	us-gaap_FeesAndCommissionsOther
Namespace Prefix:	us-gaap_
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=26872669&loc=d3e20235-122688

+ Details

Name:	us-gaap_ManagementFeesRevenue
Namespace Prefix:	us-gaap_
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

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

- 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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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Details

Name:	dei_EntityByLocationAxis=atax_UNLProjectMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_MajorityOwnedSubsidiaryUnconsolidatedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_OtherOwnershipInterestsByNameAxis=atax_TotalOwnersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=us-gaap_AffiliatedEntityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_RealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=us-gaap_UnconsolidatedPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: