Fair Value of Financial Instruments - Estimated Fair Values and Related Carrying or Notional Amounts (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Financial Assets:
Securities - available-for-sale	$ 307,812	$ 222,293
Reported Value Measurement [Member]
Financial Assets:
Cash and cash equivalents	175,706	51,296
Interest-bearing time deposits	4,653	4,309
Securities - available-for-sale	307,812	222,293
Other securities	5,939	5,810
Loans held for sale	7,740	4,248
Loans, net	1,289,318	1,211,771
Interest receivable	6,188	6,769
Financial Liabilities:
Total Deposits	1,596,162	1,288,347
Fed funds purchased and securities sold under agreement to repurchase	30,239	48,073
Federal Home Loan Bank advances	17,861	24,806
Interest payable	338	754
Fair Value [Member]
Financial Assets:
Cash and cash equivalents	175,706	51,296
Interest-bearing time deposits	4,677	4,331
Securities - available-for-sale	307,812	222,293
Other securities	5,939	5,810
Loans held for sale	7,740	4,248
Loans, net	1,261,440	1,188,014
Interest receivable	6,188	6,769
Financial Liabilities:
Total Deposits	1,605,890	1,288,792
Fed funds purchased and securities sold under agreement to repurchase	30,239	48,073
Federal Home Loan Bank advances	17,872	24,811
Interest payable	338	754
Level 1 [Member]
Financial Assets:
Cash and cash equivalents	175,706	51,296
Securities - available-for-sale		10,021
Level 2 [Member]
Financial Assets:
Interest-bearing time deposits	4,677	4,331
Securities - available-for-sale	306,250	210,782
Financial Liabilities:
Total Deposits	351,147	265,156
Level 3 [Member]
Financial Assets:
Securities - available-for-sale	1,562	1,490
Other securities	5,939	5,810
Loans held for sale	7,740	4,248
Loans, net	1,261,440	1,188,014
Interest receivable	6,188	6,769
Financial Liabilities:
Total Deposits	1,254,743	1,023,636
Fed funds purchased and securities sold under agreement to repurchase	30,239	48,073
Federal Home Loan Bank advances	17,872	24,811
Interest payable	338	754
Interest Bearing Deposits [Member] | Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	997,462	746,628
Interest Bearing Deposits [Member] | Fair Value [Member]
Financial Liabilities:
Total Deposits	1,004,608	746,628
Interest Bearing Deposits [Member] | Level 3 [Member]
Financial Liabilities:
Total Deposits	1,004,608	746,628
Non Interest Bearing Deposits [Member] | Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	351,147	265,156
Non Interest Bearing Deposits [Member] | Fair Value [Member]
Financial Liabilities:
Total Deposits	351,147	265,156
Non Interest Bearing Deposits [Member] | Level 2 [Member]
Financial Liabilities:
Total Deposits	351,147	265,156
Time Deposits [Member] | Reported Value Measurement [Member]
Financial Liabilities:
Total Deposits	247,553	276,563
Time Deposits [Member] | Fair Value [Member]
Financial Liabilities:
Total Deposits	250,135	277,008
Time Deposits [Member] | Level 3 [Member]
Financial Liabilities:
Total Deposits	$ 250,135	$ 277,008