PHC Certificates Mark to Market PHC (Details) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value, held in trust	$ 90,016,872	$ 47,366,656
Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	56,801,062	58,869,789
Cumulative Unrealized Gain, held in trust	756,853	1,847,819
Cumulative Unrealized Loss, held in trust	(399,847)	(10,318)
Estimated Fair Value, held in trust	57,158,068	60,707,290
Public Housing Capital Fund Trust I [Member] \| Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	26,077,158	27,274,451
Cumulative Unrealized Gain, held in trust	672,097	1,482,376
Estimated Fair Value, held in trust	$ 26,749,255	$ 28,756,827
Public Housing Capital Fund Trust I [Member] \| Public housing capital fund trusts [Member] \| Standard & Poor's, AA- Rating [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted Average Lives (Years)	8 years 3 months 22 days	9 years 3 months
Investment Rating	AA-	AA-
Weighted Average Interest Rate Over Life	5.36%	5.33%
Public Housing Capital Fund Trust II [Member] \| Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	$ 10,600,967	$ 11,081,987
Cumulative Unrealized Gain, held in trust	84,756	365,443
Estimated Fair Value, held in trust	$ 10,685,723	$ 11,447,430
Public Housing Capital Fund Trust II [Member] \| Public housing capital fund trusts [Member] \| Standard & Poor's, A+ Rating [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted Average Lives (Years)	7 years 7 months 24 days	8 years 8 months 1 day
Investment Rating	A+	A+
Weighted Average Interest Rate Over Life	4.31%	4.29%
Public Housing Capital Fund Trust III [Member] \| Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	$ 20,122,937	$ 20,513,351
Cumulative Unrealized Loss, held in trust	(399,847)	(10,318)
Estimated Fair Value, held in trust	$ 19,723,090	$ 20,503,033
Public Housing Capital Fund Trust III [Member] \| Public housing capital fund trusts [Member] \| Standard & Poor's, BBB Rating [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted Average Lives (Years)	8 years 9 months 15 days	9 years 9 months 22 days
Investment Rating	BBB	BBB
Weighted Average Interest Rate Over Life	5.42%	5.42%

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

+ Details

Name:	us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

+ Details

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

- Definition

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ 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 (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

+ Details

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

- Definition

Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ 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=73527792&loc=d3e27161-111563

+ Details

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

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Description of the credit rating indicative of likelihood of repayment of the debt instrument given by a credit rating agency (for example, Standard and Poor's, Moody's, Fitch).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentCreditRating
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Weighted average interest rate of debt outstanding.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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

Name:	us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Details

Name:	atax_EntityByTrustAxis=atax_PublicHousingCapitalFundTrustIMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditRatingStandardPoorsAxis=us-gaap_StandardPoorsAAMinusRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	atax_EntityByTrustAxis=atax_PublicHousingCapitalFundTrustIiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditRatingStandardPoorsAxis=us-gaap_StandardPoorsAPlusRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	atax_EntityByTrustAxis=atax_PublicHousingCapitalFundTrustIiiMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditRatingStandardPoorsAxis=us-gaap_StandardPoorsBBBRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: