Investment Securities - Narrative (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2025 USD ($) position Investment	Dec. 31, 2024 USD ($) Investment	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-sale [Line Items]
Carrying value of securities pledged to secure public deposits and other contractual obligations		$ 419,300	$ 424,800
Pledging requirements for credit derivatives and SWAP agreements - securities	$ 0		$ 0
Number of investments in non federal issuer representing more than 10% of shareholder's equity | Investment		0	0
Maximum investment in any single non-federal issuer representing shareholders equity		10.00%	10.00%
Fair value HTM in unrealized loss with no ACL		$ 114,427	$ 115,007
Unrealized loss included in fair value of securities HTM in unrealized loss position for which an ACL has not been recorded		16,462	19,104
Fair value AFS in unrealized loss with no ACL		243,075	271,800
Unrealized loss included in fair value of securities AFS in unrealized loss position for which an ACL has not been recorded		33,552	39,575
Fair value of securities AFS in unrealized loss position for which an ACL has been recorded, net of allowance		132,500
Unrealized loss position included in fair value of securities AFS in unrealized loss position for which an ACL has been recorded		10,300
Allowance for credit losses		$ 746	839
U.S. Government Corporations and Agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Held-to-maturity, securities in unrealized loss positions, qualitative disclosure, number of positions | position		90
Debt securities, available-for-sale, unrealized loss position, number of positions | position		108
Collateralized mortgage obligations
Debt Securities, Available-for-sale [Line Items]
Fair value AFS in unrealized loss with no ACL		$ 1,630	1,685
Unrealized loss included in fair value of securities AFS in unrealized loss position for which an ACL has not been recorded		$ 114	133
Debt securities, available-for-sale, unrealized loss position, number of positions | position		2
Allowance for credit losses		$ 0	0
Corporate bonds
Debt Securities, Available-for-sale [Line Items]
Fair value AFS in unrealized loss with no ACL		994
Unrealized loss included in fair value of securities AFS in unrealized loss position for which an ACL has not been recorded		$ 1
Debt securities, available-for-sale, unrealized loss position, number of positions | position		2
Allowance for credit losses	817	$ 746	$ 839	$ 731
Number of securities | Investment		27
Available-for-sale Securities
Debt Securities, Available-for-sale [Line Items]
Accrued interest receivable		$ 1,200
Allowance for credit losses		$ 746
Equity Securities | Other noninterest income
Debt Securities, Available-for-sale [Line Items]
Marketable Security, Realized Gain (Loss)	$ 36