Adverse change rate - effective rate if 10% adverse change in market occurs

No definition available.

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

- Definition

Long-term debt financing provided through the securitization of tax-exempt mortgage revenue bonds.

+ References

No definition available.

+ Details

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

- Definition

Effective rate - the effective rate for the available for sale securities held in the portfolio

+ References

No definition available.

+ Details

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

- Definition

Percentage of Available for Sale Securities by Location

+ References

No definition available.

+ Details

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

- Definition

Weighted average base rate of mortgage revenue bonds.

+ References

No definition available.

+ Details

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

- Definition

Amount of unrealized loss before deducting unrealized gain on investments in available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

+ Details

Name:	us-gaap_AvailableForSaleSecuritiesGrossUnrealizedLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow associated with the sale of debt and equity securities classified as available-for-sale securities.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Investing Activities
-URI http://asc.fasb.org/extlink&oid=6516133

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26853-111562

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a),(b)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_InformationByCategoryOfDebtSecurityAxis=atax_A10AdverseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=atax_EffectiveRateMinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=atax_EffectiveRateMaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentGeographicRegionAxis=stpr_CA
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	invest_InvestmentGeographicRegionAxis=atax_SanAntonioTexasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=atax_TOBFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_EntityByLocationAxis=atax_ProNova20141Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Investments in Mortgage Revenue Bonds Investment in Bonds Narrative Tagging (Details) - USD ($)	1 Months Ended		3 Months Ended
	Mar. 31, 2016	Jan. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Proceeds from sale of mortgage revenue bond		$ 15,000,000	$ 9,295,000
Debt financing	$ 430,307,422		$ 430,307,422	$ 451,496,716
Weighted Average Base Rate of Mortgage Revenue Bonds	6.40%		6.40%
Adverse Change Rate	10.00%		10.00%
10% adverse [Member]
Available-for-sale Securities, Gross Unrealized Loss			$ 35,300,000
Effective rate - minimum [Member]
Effective rate	4.00%		4.00%	4.20%
Effective rate - minimum [Member] \| 10% adverse [Member]
Effective rate	4.40%		4.40%
Effective rate - maximum [Member]
Effective rate	12.00%		12.00%	12.10%
Effective rate - maximum [Member] \| 10% adverse [Member]
Effective rate	13.10%		13.10%
CALIFORNIA
Percentage of Available for Sale Securities by Location	8.00%		8.00%	8.00%
San Antonio, Texas [Member]
Percentage of Available for Sale Securities by Location	51.00%		51.00%	51.00%
TOB Facility [Member]
Debt financing		$ 11,900,000
Pro Nova 2014-1 [Member]
Proceeds from sale of mortgage revenue bond	$ 9,500,000
Pro Nova 2014-1 [Member] \| TOB Facility [Member]
Debt financing	$ 8,400,000		$ 8,400,000