Fair Values of Assets and Liabilities - Carrying Amounts and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Carrying Amount [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	$ 121,052	$ 105,051
Interest-bearing deposits	39,114	28,358
Debt Securities, Available-for-Sale	1,111,709	1,147,623
Debt Securities, Held-to-maturity	498,043	405,639
Other investments	41,614	30,954
Loans Held for sale, Amount	42,993	51,991
Financing Receivable, before Allowance for Credit Loss	9,570,815	8,983,754
Deposits	10,104,582	9,678,019
Short-term borrowings	225,874	80,139
Subordinated debt	128,385	128,305
Long-term debt	129,957	130,353
Capital Lease Obligations	4,027	4,327
Estimate of Fair Value Measurement [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	121,052	105,051
Interest-bearing deposits	39,114	28,358
Debt Securities, Available-for-Sale	1,111,709	1,147,623
Debt Securities, Held-to-maturity	442,520	336,719
Other investments	41,614	30,954
Loans Held for sale, Amount	43,096	52,219
Financing Receivable, before Allowance for Credit Loss	9,690,069	8,999,020
Deposits	10,100,566	9,672,358
Short-term borrowings	224,934	79,151
Subordinated debt	117,872	115,747
Long-term debt	130,502	129,880
Capital Lease Obligations	4,027	4,327
Estimate of Fair Value Measurement [Member] | Level 1 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	121,052	105,051
Interest-bearing deposits	39,114	28,358
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-maturity	0	0
Other investments	0	0
Loans Held for sale, Amount	0	0
Financing Receivable, before Allowance for Credit Loss	0	0
Deposits	0	0
Short-term borrowings	0	0
Subordinated debt	0	0
Long-term debt	0	0
Capital Lease Obligations	0	0
Estimate of Fair Value Measurement [Member] | Level 2 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Debt Securities, Available-for-Sale	1,111,709	1,147,623
Debt Securities, Held-to-maturity	442,520	336,719
Other investments	35,882	25,222
Loans Held for sale, Amount	43,096	52,219
Financing Receivable, before Allowance for Credit Loss	70,774	39,407
Deposits	10,100,566	9,672,358
Short-term borrowings	224,934	79,151
Subordinated debt	0	0
Long-term debt	130,502	129,880
Capital Lease Obligations	4,027	4,327
Estimate of Fair Value Measurement [Member] | Level 3 [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Cash and due from banks	0	0
Interest-bearing deposits	0	0
Debt Securities, Available-for-Sale	0	0
Debt Securities, Held-to-maturity	0	0
Other investments	5,732	5,732
Loans Held for sale, Amount	0	0
Financing Receivable, before Allowance for Credit Loss	9,619,295	8,959,613
Deposits	0	0
Short-term borrowings	0	0
Subordinated debt	117,872	115,747
Long-term debt	0	0
Capital Lease Obligations	0	0
Cash and due from banks	121,052	105,051
Interest-bearing deposits	39,114	28,358
Debt Securities, Available-for-Sale	1,111,709	1,147,623
Debt Securities, Held-to-maturity	498,043	405,639
Other investments	41,614	30,954
Financing Receivable, before Allowance for Credit Loss	9,570,815	8,983,754
Deposits	10,104,582	9,678,019
Short-term borrowings	225,874	80,139
Subordinated debt	128,385	128,305
Long-term debt	129,957	130,353
Capital Lease Obligations	$ 4,027	$ 4,327