Mortgage Revenue Bonds - Schedule of Percentage of MRBs Principal Outstanding (Details)	Dec. 31, 2021	Dec. 31, 2020
TX [Member]
Schedule Of Available For Sale Securities [Line Items]
Percentage of available for sale securities by location	41.00%	43.00%
CA [Member]
Schedule Of Available For Sale Securities [Line Items]
Percentage of available for sale securities by location	23.00%	17.00%
SC [Member]
Schedule Of Available For Sale Securities [Line Items]
Percentage of available for sale securities by location	11.00%	17.00%