Federal Home Loan Bank and Short-term Borrowings (Detail) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($) item shares	Dec. 31, 2017 USD ($)
Short-term Debt [Line Items]
Federal home loan bank shares owned \| shares	24,756
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	$ 102.7
Short term advances	50.0
Average short-term borrowings	$ 31.7	$ 1.5
Debt instrument, maturity date	Jan. 11, 2019
Debt instrument, interest rate, stated percentage	3.00%
Number of financial institution lending credit facility \| item	2
Number of borrowing days	14 days
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. 23, 2019
Debt instrument, interest rate, stated percentage	2.48%
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. 22, 2019
Debt instrument, interest rate, stated percentage	2.73%
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. 01, 2019
Debt instrument, interest rate, stated percentage	2.48%
Convertible advances maturing on January 17, 2019 \| Federal Home Loan Bank of Atlanta [Member]
Short-term Debt [Line Items]
Convertible debt	$ 15.0
Debt instrument, maturity date	Jan. 17, 2019
Debt instrument, interest rate, stated percentage	2.49%
Convertible advances maturing on November 21, 2019 \| Federal Home Loan Bank of Atlanta [Member]
Short-term Debt [Line Items]
Convertible debt	$ 15.0
Debt instrument, maturity date	Nov. 21, 2019
Debt instrument, interest rate, stated percentage	2.65%
Financial Bank One [Member]
Short-term Debt [Line Items]
Line of credit, amount available for borrowing	$ 5.0
Financial Bank Two [Member]
Short-term Debt [Line Items]
Line of credit, amount available for borrowing	$ 8.0
Minimum
Short-term Debt [Line Items]
Weighted average interest rate	2.57%
Maximum
Short-term Debt [Line Items]
Weighted average interest rate		2.97%

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Amount Of Credit Available On Total Assets.

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Federal Home Loan Bank Shares Owned.

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Amount of advances from Federal Home Loan Bank (FHLBank) maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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