PHC Certificates - Additional Information (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) Option Security	Sep. 30, 2018 USD ($) Option Security
Schedule Of Available For Sale Securities [Line Items]
Impairment charge	$ 309,958	$ 1,141,020
LIFERS [Member]
Schedule Of Available For Sale Securities [Line Items]
Available-for-Sale Securities, Ownership Percentage		100.00%
Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Number of tender option bonds | Option	3	3
Impairment charge	$ 310,000	$ 1,100,000
Impairment charge recognized for number of securities | Security	3	3