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

This element represents the portion of the balance sheet assertion valued at fair value by the entity, which is held in trust, whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may by ued in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all sescuritized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

No definition available.

Name:	atax_AvailableForSaleSecuritiesFairValueDisclosureHeldInTrust
Namespace Prefix:	atax_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

This element represents the portion of the balance sheet assertion valued at fair value by the entity, which is held in a trust for public housing authory bonds, whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may by ued in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all sescuritized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

No definition available.

Name:	atax_AvailableForSaleSecuritiesFairValueDisclosurePublicHousingAuthority
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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. This does not include premiums.

No definition available.

Name:	atax_AvailableForSaleSecuritiesNotIncludingPremiums
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Available-for-sale Security, Maturity Date at a point in time

No definition available.

Name:	atax_AvailableForSaleSecurityMaturityDateAtPointInTime
Namespace Prefix:	atax_
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Long-term debt financing provided through the securitization of tax-exempt mortgage revenue bonds.

No definition available.

Name:	atax_DebtFinancing
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Long-term debt financing provided through the securitization of mortgage revenue bonds after payments of expenses.

No definition available.

Name:	atax_DebtFinancingNet
Namespace Prefix:	atax_
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Balance Type:	credit
Period Type:	duration

The addition of a variable interest rate and a fixed interest rate for each debt instrument.

No definition available.

Name:	atax_DebtInstrumentTotalRateofBorrowing
Namespace Prefix:	atax_
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Balance Type:	na
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Derivative, Maturity Date at a point in time

No definition available.

Name:	atax_DerivativeMaturityDateAtPointInTime
Namespace Prefix:	atax_
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Balance Type:	na
Period Type:	duration

Number of Available for Sale Securities, Held in a Trust

No definition available.

Name:	atax_NumberOfAvailableForSaleSecuritiesHeldInTrust
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Number of Available for Sale Securities, Mortgage Backed Securities

No definition available.

Name:	atax_NumberOfAvailableForSaleSecuritiesMortgageBackedSecurities
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Balance Type:	na
Period Type:	instant

TOB Financing - Tender Option Bond Financing Facility

No definition available.

Name:	atax_TobFinancing
Namespace Prefix:	atax_
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Balance Type:	credit
Period Type:	instant

Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

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-Section S99

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-Subparagraph (SX 210.9-03.1)

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-Subparagraph (SX 210.7-03.(a),2)

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-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 2

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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

No definition available.

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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Period Type:	duration

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

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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-Name Regulation S-X (SX)

-Number 210

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Weighted average interest rate of debt outstanding.

No definition available.

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Nominal or face amount used to calculate payments on the derivative asset.

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-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

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-Glossary Notional Amount

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Fixed interest rate related to the interest rate derivative.

No definition available.

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The net cash inflow or outflow for the increase (decrease) associated with funds that are not available for withdrawal or use (such as funds held in escrow) and are associated with underlying transactions that are classified as investing activities.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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-Name Accounting Standards Codification

-Topic 942

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

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Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
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Period Type:	instant

The effective interest rate during the reporting period.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

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-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
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Carrying amount of long-term debt, net of unamortized discount or premium, including current and noncurrent amounts. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Publisher SEC

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-Number 210

-Section 02

-Paragraph 20, 22

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-Name Accounting Standards Codification

-Topic 944

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

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The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

Name:	us-gaap_LongTermDebtPercentageBearingFixedInterestRate
Namespace Prefix:	us-gaap_
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The cash outflow to acquire debt and equity securities not classified as either held-to-maturity securities or trading securities which would be classified as available-for-sale securities and reported at fair value, with unrealized gains and losses excluded from earnings and reported in a separate component of shareholders' equity.

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-Name Accounting Standards Codification

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-Subparagraph (a),(b)

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The cash inflow associated with maturities (principal being due), prepayments and calls (requests of early payments) on securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities.

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-Name Accounting Standards Codification

-Glossary Investing Activities

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-Name Accounting Standards Codification

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The cash inflow from a borrowing supported by a written promise to pay an obligation.

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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-Name Accounting Standards Codification

-Topic 230

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

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

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-Publisher FASB

-Name Accounting Standards Codification

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-Topic 230

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-Subparagraph (a),(b)

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Name:	us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

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-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

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-Paragraph 1

-Subparagraph (SX 210.5-02.1)

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Name:	us-gaap_RestrictedCashAndCashEquivalents
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The portion of the carrying amount of short-term borrowings outstanding as of the balance sheet date which accrues interest at a set, unchanging rate.

No definition available.

Name:	us-gaap_ShortTermDebtPercentageBearingFixedInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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Name:	atax_EntityByTrustAxis=atax_MortgageBackedSecurityTrust5MemberMember
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Name:	dei_EntityByLocationAxis=atax_ArborsAtHickoryRidgeMember
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Name:	dei_EntityByLocationAxis=atax_LostCreekMember
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Name:	dei_EntityByLocationAxis=atax_WoodlandParkMember
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Name:	us-gaap_CreditFacilityAxis=atax_BankersTrustMember
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Name:	us-gaap_CreditFacilityAxis=atax_FivePointsBankMember
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