Commitments and Contingencies - Additional Information (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Commitments And Contingencies [Line Items]
Commitment amount	$ 0	$ 0
Housing Equity Fund of Virginia XXIV L.L.C [Member]
Commitments And Contingencies [Line Items]
Commitment amount		5,000,000.0
Washington Housing Initiative Impact Pool L.L.C [Member]
Commitments And Contingencies [Line Items]
Commitment amount		$ 2,000,000.0
Commitment funded Balance	656,000
Commitment unfunded balance	$ 1,300,000