The percentage of ownership of available-for-sale securities.

No definition available.

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

- Definition

Amount received upon sale of business.

+ References

No definition available.

+ Details

Name:	atax_BusinessDisposalSalesPrice
Namespace Prefix:	atax_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Number of Installments of Contributed Capital

+ References

No definition available.

+ Details

Name:	atax_NumberOfInstallmentsOfContributedCapital
Namespace Prefix:	atax_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of owners of the consolidated VIE's.

+ References

No definition available.

+ Details

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

- Definition

Number of Partners of a Company.

+ References

No definition available.

+ Details

Name:	atax_NumberOfPartners
Namespace Prefix:	atax_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- 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

The total cost of the acquired entity including the cash paid to shareholders of acquired entities, fair value of debt and equity securities issued to shareholders of acquired entities, the fair value of the liabilities assumed, and direct costs of the acquisition.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 141

-Paragraph 51

-Subparagraph d

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

Name:	us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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

- Definition

Total contributions made by each class of partners (i.e., general, limited and preferred partners).

+ References

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

-Publisher AICPA

-Name Practice Bulletin (PB)

-Number 14

-Paragraph 15

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187171-122770

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 87-21

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

The difference between the value of the consideration received by the Entity on the sale or disposal and the consideration received by the Entity, including any tax related impact.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2941-110230

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

+ Details

Name:	us-gaap_SignificantAcquisitionsAndDisposalsGainLossOnSaleOrDisposalNetOfTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 5A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=7880789&loc=SL6759159-111685

+ Details

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

Variable Interest Entities VIE Considerations (Details) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 31, 2010 installments	Sep. 30, 2012	Dec. 31, 2012 limited
Number of Variable Interest Entities			5
Consolidated Properties [Member]
Number of Variable Interest Entities			3
Unconsolidated Properties [Member]
Number of Variable Interest Entities			2
Total Owners [Member]
Number of Owners			4
Related party owner [Member]
Number of Owners			3
churchland [Member]
business disposal, sales price		8,100,000
Significant Acquisitions and Disposals, Gain (Loss) on Sale or Disposal, Net of Tax		1,300,000
Maples on 97th [Member]
Business Acquisition, Cost of Acquired Entity, Purchase Price		5,500,000
Ashley Square [Member]
Available-for-Sale Securities, Ownership Percentage			100.00%
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage			99.00%
Cross Creek [Member]
Available-for-Sale Securities, Ownership Percentage		100.00%
Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage			99.00%
Number of Partners			3
Partners' Capital Account, Contributions	2,200,000
Number of Installments of Contributed Capital	3
Noncontrolling Interest, Ownership Percentage by Parent			1.00%
First Installment [Member] \| Cross Creek [Member]
Partners' Capital Account, Contributions	$ 563,000