Issuances of Beneficial Unit Certificates - Additional Information (Details) - At The Market Offering [Member] - BUCs - Restricted and Unrestricted [Member]	1 Months Ended
Dec. 31, 2019 USD ($)
Issuances of Beneficial Unit Certificates [Line Items]
Partnership capital unit, amount authorized	$ 225,000,000.0
Registration statement expiration date	2022-12

Registration statement expiration date in month and year (YYYY-MM).

No definition available.

Name:	atax_RegistrationStatementExpirationDate
Namespace Prefix:	atax_
Data Type:	xbrli:gYearMonthItemType
Balance Type:	na
Period Type:	duration