Federal Home Loan Bank and Short-term Borrowings (Detail) $ in Millions	12 Months Ended
Dec. 31, 2019 USD ($) item shares	Dec. 31, 2018 USD ($)
Short-term Debt [Line Items]
Federal home loan bank shares owned \| shares	14,343
Percentage of investment to be maintained on total assets	0.09%
Amount of dollar cap on total assets	$ 15.0
Additional percentage of investment to be maintained on total advances	4.25%
Percentage of credit available on total assets	25.00%
Amount of credit available on total assets	$ 95.9
Short term advances	25.0
Average short-term borrowings	$ 25.6	$ 31.7
Number of financial institution lending credit facility \| item	2
Convertible advances maturing on July 23, 2019 \| Federal Home Loan Bank of Atlanta [Member]
Short-term Debt [Line Items]
Convertible debt	$ 5.0
Debt instrument, maturity date	Jul. 24, 2020
Debt instrument, interest rate, stated percentage	1.96%
Convertible advances maturing on August 22, 2019 \| Federal Home Loan Bank of Atlanta [Member]
Short-term Debt [Line Items]
Convertible debt	$ 5.0
Debt instrument, maturity date	Aug. 24, 2020
Debt instrument, interest rate, stated percentage	1.93%
Convertible advances maturing on November 1, 2019 \| Federal Home Loan Bank of Atlanta [Member]
Short-term Debt [Line Items]
Convertible debt	$ 10.0
Debt instrument, maturity date	Nov. 02, 2020
Debt instrument, interest rate, stated percentage	1.91%
Convertible advances maturing on November 21, 2019 \| Federal Home Loan Bank of Atlanta [Member]
Short-term Debt [Line Items]
Convertible debt	$ 5.0
Debt instrument, maturity date	Dec. 28, 2020
Debt instrument, interest rate, stated percentage	1.78%
Financial Bank One [Member]
Short-term Debt [Line Items]
Line of credit, amount available for borrowing	$ 9.0
Financial Bank Two [Member]
Short-term Debt [Line Items]
Line of credit, amount available for borrowing	8.0
Financial Bank Three [Member]
Short-term Debt [Line Items]
Line of credit, amount available for borrowing	$ 10.4
Minimum
Short-term Debt [Line Items]
Weighted average interest rate	2.26%
Maximum
Short-term Debt [Line Items]
Weighted average interest rate		2.39%

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Amount Of Credit Available On Total Assets.

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