Public Housing Capital Fund Trust ("PHC") Certificates - Additional Information (Details)		3 Months Ended
Jan. 30, 2020 USD ($)	Mar. 31, 2020 USD ($) Option
Public housing capital fund trusts [Member]
Schedule Of Available For Sale Securities [Line Items]
Number of tender option bonds \| Option		3
Proceeds from sale of certificates		$ 43,349,357
PHC Certificates [Member]
Schedule Of Available For Sale Securities [Line Items]
Proceeds from sale of certificates	$ 43,300,000
Gain on sale of securities	$ 1,400,000

Amount of cash inflow from sale of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118954083&loc=d3e26853-111562

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3151-108585

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118932676&loc=d3e3179-108585

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