Transactions with Related Parties - Summary of Transactions Between Borrowers of Partnership's MRBs and Affiliates (Parenthetical) (Details)	12 Months Ended
Dec. 31, 2019
Related Party Transactions [Abstract]
Rate for administration fees receivable	0.45%

Rate for administration fees - rate charged on the bonds and loans collateralized by the underlying properties for administration of the assets

No definition available.

Name:	atax_RateForAdministrationFees
Namespace Prefix:	atax_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration