PHC Certificates - Schedule of Investments in PHC Certificates (Details) - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Estimated Fair Value, held in trust	$ 74,758,296	$ 77,971,208
Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	49,921,046	50,167,034
Cumulative Unrealized Loss, held in trust	(981,792)	(525,446)
Estimated Fair Value, held in trust	48,939,254	49,641,588
Public Housing Capital Fund Trust I [Member] \| Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	25,076,538	25,109,305
Cumulative Unrealized Loss, held in trust	(240,309)
Estimated Fair Value, held in trust	$ 24,836,229	$ 25,109,305
Public Housing Capital Fund Trust I [Member] \| Public housing capital fund trusts [Member] \| Standard & Poor's, AA- Rating [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted Average Lives (Years)	7 years 3 months 3 days	7 years 3 months 21 days
Investment Rating	AA-	AA-
Weighted Average Interest Rate Over Life	5.37%	5.39%
Public Housing Capital Fund Trust II [Member] \| Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	$ 9,385,935	$ 9,606,480
Cumulative Unrealized Loss, held in trust	(298,568)	(248,189)
Estimated Fair Value, held in trust	$ 9,087,367	$ 9,358,291
Public Housing Capital Fund Trust II [Member] \| Public housing capital fund trusts [Member] \| Standard & Poor's, A+ Rating [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted Average Lives (Years)	6 years 3 months 18 days	6 years 4 months 13 days
Investment Rating	A+	A+
Weighted Average Interest Rate Over Life	4.33%	4.32%
Public Housing Capital Fund Trust III [Member] \| Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost Basis, Held in Trust	$ 15,458,573	$ 15,451,249
Cumulative Unrealized Loss, held in trust	(442,915)	(277,257)
Estimated Fair Value, held in trust	$ 15,015,658	$ 15,173,992
Public Housing Capital Fund Trust III [Member] \| Public housing capital fund trusts [Member] \| Standard & Poor's, BBB Rating [Member]
Schedule Of Available For Sale Securities [Line Items]
Weighted Average Lives (Years)	7 years 6 months 25 days	7 years 7 months 9 days
Investment Rating	BBB	BBB
Weighted Average Interest Rate Over Life	5.29%	5.23%

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Description of the credit rating indicative of likelihood of repayment of the debt instrument given by a credit rating agency (for example, Standard and Poor's, Moody's, Fitch).

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