Debt Financing - Additional Information (Details)		1 Months Ended						9 Months Ended
		Aug. 31, 2018 USD ($) Security	Apr. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017 USD ($) Trust	Feb. 28, 2017 USD ($) Agreement	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($)
Debt Instrument [Line Items]
Deferred financing costs - net									$ 3,546,843
Farnam Capital Advisors, LLC [Member]
Debt Instrument [Line Items]
Consulting fees	[1]							$ 921,000
Term A/B Trust [Member]
Debt Instrument [Line Items]
Deferred financing costs - net						$ 47,000	$ 1,200,000
Number of term trusts refinanced | Trust						4
Term A/B Trust [Member] | Farnam Capital Advisors, LLC [Member]
Debt Instrument [Line Items]
Consulting fees							$ 921,000
Mortgage Revenue Bonds [Member] | Term A/B Trust [Member]
Debt Instrument [Line Items]
Number of new agreements | Agreement							19
Variable - TOB [Member]
Debt Instrument [Line Items]
Debt instrument extended maturity period			2019-05		2018-05
Fixed - M45 [Member] | Mortgage Revenue Bonds [Member] | TEBS Financings [Member] | ATAX TEBS IV, LLC [Member]
Debt Instrument [Line Items]
Long-term debt financing facility par value		$ 260,600,000
Number of securities provided for long-term debt financing facility | Security		25
Fixed - M45 [Member] | Mortgage Revenue Bonds [Member] | Term A/B Trust [Member]
Debt Instrument [Line Items]
Number of securities collapsed prior to closing of financing | Security		24
Deferred financing costs - net		$ 371,000
Fixed - M45 [Member] | Class A TEBS Certificates [Member] | TEBS Financings [Member]
Debt Instrument [Line Items]
Long-term debt financing facility par value		$ 221,500,000
Variable - M24 [Member] | TEBS Financings [Member] | ATAX TEBS IV, LLC [Member]
Debt Instrument [Line Items]
Debt instrument extended maturity date				Sep. 15, 2020

[1] Fees are paid to Farnam Cap related to consulting services when certain debt financing facilities are acquired by the Partnership.