Mortgage Revenue Bonds - Schedule of MRBs Redeemed (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) Unit	Dec. 31, 2019 USD ($) Unit
Schedule Of Available For Sale Securities [Line Items]
Units	3,756
Montevista [Member] | Series B [Member] | San Pablo, CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Units		82
Original Maturity Date		Jul. 01, 2021
Interest Rate		5.75%
Mortgage Revenue Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Principal Outstanding at Date of Redemption | $	$ 9,583,000	$ 11,802,000
Mortgage Revenue Bonds [Member] | Solano Vista [Member] | Series B [Member] | Vallejo, CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Redeemed	January
Units	96
Original Maturity Date	Jan. 01, 2021
Interest Rate	5.85%
Principal Outstanding at Date of Redemption | $	$ 3,103,000
Mortgage Revenue Bonds [Member] | Montevista [Member] | Series B [Member] | San Pablo, CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Redeemed	August
Units	82
Original Maturity Date	Jul. 01, 2021
Interest Rate	8.00%
Principal Outstanding at Date of Redemption | $	$ 6,480,000
Mortgage Revenue Bonds [Member] | Seasons San Juan Capistrano [Member] | Series B [Member] | San Juan Capistrano California [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Redeemed		January
Units		112
Original Maturity Date		Jan. 01, 2019
Interest Rate		8.00%
Principal Outstanding at Date of Redemption | $		$ 5,574,000
Mortgage Revenue Bonds [Member] | Courtyard [Member] | Series B [Member] | Fullerton, CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Month Redeemed		April
Units		108
Original Maturity Date		Jun. 01, 2019
Interest Rate		8.00%
Principal Outstanding at Date of Redemption | $		$ 6,228,000