Fair Value Measurement - Carrying Amount and Fair Value of Financial Instruments Carried at Amortized Cost (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Financial Assets:
Cash and due from financial institutions	$ 63,155	$ 60,406
Investments in time deposits	1,450	1,225
Other securities	30,352	29,998
Financing Receivable, after Allowance for Credit Loss	3,041,561	2,824,568
Mortgage servicing rights	3,854	3,018	$ 2,689
Accrued interest receivable	13,453	12,819
Financial Liabilities:
Time deposits	944,954
Short-term FHLB advances	339,000	338,000
Long-term FHLB advances	1,501	2,392
Other borrowings	6,293	9,859
Carrying Amount [Member]
Financial Assets:
Cash and due from financial institutions	63,155	60,406
Investments in time deposits	1,450	1,225
Other securities	30,352	29,998
Loans, held for sale	665	1,725
Financing Receivable, after Allowance for Credit Loss	3,041,561	2,824,568
Mortgage servicing rights	2,877	3,018
Accrued interest receivable	13,453	12,819
Financial Liabilities:
Nonmaturing deposits	2,266,916	2,084,216
Time deposits	944,954	900,812
Short-term FHLB advances	339,000	338,000
Long-term FHLB advances	1,501	2,392
Subordinated debentures	104,089	103,943
Other borrowings	6,293	9,859
Accrued interest payable	9,518	9,525
Total Fair Value [Member]
Financial Assets:
Cash and due from financial institutions	63,155	60,406
Investments in time deposits	1,450	1,225
Other securities	30,352	29,998
Loans, held for sale	665	1,725
Financing Receivable, after Allowance for Credit Loss	2,919,899	2,679,988
Mortgage servicing rights	3,854	3,018
Accrued interest receivable	13,453	12,819
Financial Liabilities:
Nonmaturing deposits	2,266,916	2,084,216
Time deposits	948,734	899,443
Short-term FHLB advances	339,000	337,267
Long-term FHLB advances	1,418	2,419
Subordinated debentures	101,175	101,563
Other borrowings	6,293	9,859
Accrued interest payable	9,518	9,525
(Level 1) [Member]
Financial Assets:
Cash and due from financial institutions	63,155	60,406
Other securities	30,352	29,998
Loans, held for sale	665	1,725
Accrued interest receivable	13,453	12,819
Financial Liabilities:
Nonmaturing deposits	2,266,916	2,084,216
Short-term FHLB advances	339,000	337,267
Accrued interest payable	9,518	9,525
(Level 2) [Member]
Financial Assets:
Investments in time deposits	1,450	1,225
(Level 3) [Member]
Financial Assets:
Financing Receivable, after Allowance for Credit Loss	2,919,899	2,679,988
Mortgage servicing rights	3,854	3,018
Financial Liabilities:
Time deposits	948,734	899,443
Long-term FHLB advances	1,418	2,419
Subordinated debentures	101,175	101,563
Other borrowings	$ 6,293	$ 9,859