Fair Value of Financial Instruments - Estimated Fair Values and Related Carrying or Notional Amounts (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financial Assets:
Securities - available-for-sale	$ 259,041	$ 222,293
Reported Value Measurement [Member]
Financial Assets:
Cash and cash equivalents	87,753	51,296
Interest-bearing time deposits	4,657	4,309
Securities - available-for-sale	259,041	222,293
Other securities	5,827	5,810
Loans held for sale	7,621	4,248
Loans, net	1,351,979	1,211,771
Interest receivable	6,879	6,769
Financial Liabilities:
Total Deposits	1,518,873	1,288,347
Federal funds purchased and securities sold under agreement to repurchase	29,859	48,073
Federal Home Loan Bank advances	17,724	24,806
Interest payable	558	754
Fair Value [Member]
Financial Assets:
Cash and cash equivalents	87,753	51,296
Interest-bearing time deposits	4,718	4,331
Securities - available-for-sale	259,041	222,293
Other securities	5,827	5,810
Loans held for sale	7,621	4,248
Loans, net	1,324,451	1,188,014
Interest receivable	6,879	6,769
Financial Liabilities:
Total Deposits	1,521,796	1,288,855
Federal funds purchased and securities sold under agreement to repurchase	29,859	48,073
Federal Home Loan Bank advances	17,737	24,811
Interest payable	558	754
Interest Bearing Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	926,851	746,628
Interest Bearing Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	926,899	746,691
Non Interest Bearing Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	330,845	265,156
Non Interest Bearing Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	330,845	265,156
Time Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	261,177	276,563
Time Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	264,052	277,008
Level 1 [Member]
Financial Assets:
Cash and cash equivalents	87,753	51,296
Securities - available-for-sale	3,004	10,021
Level 2 [Member]
Financial Assets:
Interest-bearing time deposits	4,718	4,331
Securities - available-for-sale	254,452	210,782
Financial Liabilities:
Total Deposits	330,845	265,156
Level 2 [Member] \| Non Interest Bearing Deposits [Member]
Financial Liabilities:
Total Deposits	330,845	265,156
Level 3 [Member]
Financial Assets:
Securities - available-for-sale	1,585	1,490
Other securities	5,827	5,810
Loans held for sale	7,621	4,248
Loans, net	1,324,451	1,188,014
Interest receivable	6,879	6,769
Financial Liabilities:
Total Deposits	1,190,951	1,023,699
Federal funds purchased and securities sold under agreement to repurchase	29,859	48,073
Federal Home Loan Bank advances	17,737	24,811
Interest payable	558	754
Level 3 [Member] \| Interest Bearing Deposits [Member]
Financial Liabilities:
Total Deposits	926,899	746,691
Level 3 [Member] \| Time Deposits [Member]
Financial Liabilities:
Total Deposits	$ 264,052	$ 277,008

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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