Debt financing reset frequency.

No definition available.

Name:	atax_DebtFinancingResetFrequency
Namespace Prefix:	atax_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of the interest rate as being fixed or variable, and, if variable, identification of the index or rate on which the interest rate is based and the number of points or percentage added to that index or rate to set the rate, and other pertinent information, such as frequency of rate resets.

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+ Details

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

- Definition

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

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+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ 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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

- Definition

The effective interest rate during the reporting period.

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

- 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.

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No definition available.

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

- Definition

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.

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+ Details

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

- Details

Name:	us-gaap_CreditFacilityAxis=atax_BankersTrustOperatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=atax_BankersTrustMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=atax_ThreePointEightEightPercentageInterestBearingLineOfCreditMember
Namespace Prefix:
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Summary of Unsecured Lines of Credit (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2016	May 31, 2017	Apr. 30, 2017
Line Of Credit Facility [Line Items]
Lines of credit		$ 40,000,000
Bankers Trust Operating [Member]
Line Of Credit Facility [Line Items]
Lines of credit	$ 0
Unsecured Lines of Credit [Member]
Line Of Credit Facility [Line Items]
Lines of credit		40,000,000
Line of credit facility maximum borrowing capacity	60,000,000	47,500,000
Unsecured Lines of Credit [Member] \| Bankers Trust [Member]
Line Of Credit Facility [Line Items]
Line of credit facility maximum borrowing capacity				$ 50,000,000
Unsecured Lines of Credit [Member] \| Bankers Trust Operating [Member]
Line Of Credit Facility [Line Items]
Line of credit facility maximum borrowing capacity			$ 10,000,000	$ 7,500,000
Unsecured Lines of Credit [Member] \| 4.22% Interest Bearing Line of Credit [Member] \| Bankers Trust [Member]
Line Of Credit Facility [Line Items]
Line of credit facility maximum borrowing capacity	$ 50,000,000
Debt instrument, maturity date	May 31, 2019
Variable / Fixed	Variable
Reset Frequency	Monthly
Line of credit facility, interest rate during period	4.22%
Unsecured Lines of Credit [Member] \| 4.47% Interest Bearing Line of Credit [Member] \| Bankers Trust Operating [Member]
Line Of Credit Facility [Line Items]
Line of credit facility maximum borrowing capacity	$ 10,000,000
Debt instrument, maturity date	May 31, 2019
Variable / Fixed	Variable
Reset Frequency	Monthly
Line of credit facility, interest rate during period	4.47%
Unsecured Lines of Credit [Member] \| 3.13% Interest Bearing Line of Credit [Member] \| Bankers Trust [Member]
Line Of Credit Facility [Line Items]
Lines of credit		40,000,000
Line of credit facility maximum borrowing capacity		$ 40,000,000
Debt instrument, maturity date		May 31, 2018
Variable / Fixed		Variable
Reset Frequency		Monthly
Line of credit facility, interest rate during period		3.13%
Unsecured Lines of Credit [Member] \| 3.88% Interest Bearing Line of Credit [Member] \| Bankers Trust Operating [Member]
Line Of Credit Facility [Line Items]
Line of credit facility maximum borrowing capacity		$ 7,500,000
Debt instrument, maturity date		Mar. 31, 2018
Variable / Fixed		Variable
Reset Frequency		Monthly
Line of credit facility, interest rate during period		3.88%