Other Assets - Narrative Tagging (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Redemptions of taxable bonds	$ 648,439,860	$ 534,745,500
Silver Moon [Member] \| Series B [Member]
Redemptions of taxable bonds	$ 500,000

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.

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