Fair Value of Financial Instruments - Estimated Fair Values and Related Carrying or Notional Amounts (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Financial Assets:
Securities - available-for-sale	$ 190,465	$ 168,447
Reported Value Measurement [Member]
Financial Assets:
Cash and cash equivalents	114,592	38,365
Interest-bearing time deposits	4,554	4,019
Securities - available-for-sale	190,465	168,447
Other securities	5,789	3,679
Loans held for sale	606	495
Loans, net	1,151,937	839,599
Interest receivable	7,830	4,542
Financial Liabilities:
Total Deposits	1,278,028	928,790
Federal funds purchased and securities sold under agreement to repurchase	30,056	32,181
Federal Home Loan Bank advances	24,669
Interest payable	739	418
Fair Value [Member]
Financial Assets:
Cash and cash equivalents	114,592	38,365
Interest-bearing time deposits	4,554	3,954
Securities - available-for-sale	190,465	168,447
Other securities	5,789	3,679
Loans held for sale	606	495
Loans, net	1,129,954	823,914
Interest receivable	7,830	4,542
Financial Liabilities:
Total Deposits	1,278,707	928,922
Federal funds purchased and securities sold under agreement to repurchase	30,056	3,181
Federal Home Loan Bank advances	24,672
Interest payable	739	418
Interest Bearing Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	741,313	525,955
Interest Bearing Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	741,360	525,955
Non Interest Bearing Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	261,719	215,422
Non Interest Bearing Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	261,719	215,422
Time Deposits [Member] \| Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	274,996	187,413
Time Deposits [Member] \| Fair Value [Member]
Financial Liabilities:
Total Deposits	275,658	187,545
Level 1 [Member]
Financial Assets:
Cash and cash equivalents	114,592	38,365
Securities - available-for-sale	14,009	36,935
Level 2 [Member]
Financial Assets:
Interest-bearing time deposits	4,554	3,954
Securities - available-for-sale	174,947	130,085
Financial Liabilities:
Total Deposits	261,719	215,422
Level 2 [Member] \| Non Interest Bearing Deposits [Member]
Financial Liabilities:
Total Deposits	261,719	215,422
Level 3 [Member]
Financial Assets:
Securities - available-for-sale	1,509	1,427
Other securities	5,789	3,679
Loans held for sale	606	495
Loans, net	1,129,954	823,914
Interest receivable	7,830	4,542
Financial Liabilities:
Total Deposits	1,016,988	713,500
Federal funds purchased and securities sold under agreement to repurchase	30,056	32,181
Federal Home Loan Bank advances	24,672
Interest payable	739	418
Level 3 [Member] \| Interest Bearing Deposits [Member]
Financial Liabilities:
Total Deposits	741,360	525,955
Level 3 [Member] \| Time Deposits [Member]
Financial Liabilities:
Total Deposits	$ 275,658	$ 187,545

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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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