Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Deferred tax assets:
Allowance for credit losses, loans and leases	$ 18,838	$ 17,343
Deferred compensation	1,795	1,959
Actuarial adjustments on retirement benefits*	3,126	4,043
State net operating losses	3,778	3,348
Other-than-temporary impairments on equity securities	99	98
Net unrealized holding losses on securities available-for-sale and swaps	10,342	12,471
Lease liability	7,687	7,275
Other deferred tax assets	2,577	2,016
Gross deferred tax assets	48,242	48,553
Valuation allowance	(3,527)	(2,975)
Total deferred tax assets, net of valuation allowance	44,715	45,578
Deferred tax liabilities:
Mortgage servicing rights	1,885	1,785
Retirement plans	4,719	4,907
Deferred loan fees and costs	1,539	897
Acquisition-related fair value adjustments	779	902
Intangible assets	4,349	3,742
Depreciation	1,534	1,575
Right of use asset	7,013	6,596
Other deferred tax liabilities	1,104	1,045
Total deferred tax liabilities	22,922	21,449
Net deferred tax assets	$ 21,793	$ 24,129