This element represents the portion of the table assertion valued at par by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure.

No definition available.

+ Details

Name:	atax_AvailableForSaleSecuritiesAtParValue
Namespace Prefix:	atax_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Available-for-sale security, maturity date at a point in time.

+ References

No definition available.

+ Details

Name:	atax_AvailableForSaleSecurityMaturityDateAtPointInTime
Namespace Prefix:	atax_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ 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 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

The number of units in a real estate property owned as of the balance sheet date.

+ References

No definition available.

+ Details

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

- Details

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

- Details

Name:	us-gaap_AuctionMarketPreferredSecuritiesStockSeriesAxis=us-gaap_SeriesBMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentRedemptionPeriodAxis=us-gaap_DebtInstrumentRedemptionPeriodTwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Other Assets - Summary of the Terms of the Taxable Bond Redeemed and Acquired (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) Unit	Dec. 31, 2015 USD ($)	Oct. 31, 2015 Unit
Units \| Unit			2
Principal Outstanding	$ 648,439,860	$ 534,745,500
Silver Moon [Member] \| Series B [Member]
Principal Outstanding	$ 500,000
Silver Moon [Member] \| Series B [Member] \| 2016 Redemption [Member]
Units \| Unit	151
Original Maturity Date	Aug. 01, 2055
Base Interest Rate	12.00%
Principal Outstanding	$ 499,461
Silver Moon [Member] \| Series B [Member] \| 2015 Purchase Date [Member]
Units \| Unit	151
Original Maturity Date	Aug. 01, 2055
Base Interest Rate	12.00%
Principal Outstanding	$ 500,000