Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets:
Allowance for credit losses, loans and leases	$ 19,447	$ 18,838
Deferred compensation	1,693	1,795
Actuarial adjustments on retirement benefits*	1,715	3,126
State net operating losses	4,285	3,778
Other-than-temporary impairments on equity securities	0	99
Net unrealized holding losses on securities available-for-sale and swaps	9,984	10,342
Lease liability	7,029	7,687
Other deferred tax assets	2,775	2,577
Gross deferred tax assets	46,928	48,242
Valuation allowance	(3,959)	(3,527)
Total deferred tax assets, net of valuation allowance	42,969	44,715
Deferred tax liabilities:
Mortgage servicing rights	1,350	1,885
Retirement plans	4,768	4,719
Deferred loan fees and costs	1,549	1,539
Acquisition-related fair value adjustments	554	779
Intangible assets	4,843	4,349
Depreciation	1,123	1,534
Right of use asset	6,369	7,013
Other deferred tax liabilities	1,118	1,104
Total deferred tax liabilities	21,674	22,922
Net deferred tax assets	$ 21,295	$ 21,793