Securities - Available for Sale Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost, Total securities available for sale	$ 710,058	$ 672,892
Gross Unrealized Gains	882	3,059
Gross Unrealized Losses	(62,873)	(57,679)
Fair Value	648,067	618,272
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost, Total securities available for sale	100,378	71,418
Gross Unrealized Gains	303	315
Gross Unrealized Losses	(3,294)	(4,075)
Fair Value	97,387	67,658
Obligations of States and Political Subdivisions [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost, Total securities available for sale	351,635	359,452
Gross Unrealized Gains	482	2,725
Gross Unrealized Losses	(26,998)	(23,578)
Fair Value	325,119	338,599
Mortgage-back Securities in Government Sponsored Entities [Member]
Debt Securities, Available-for-Sale [Line Items]
Amortized Cost, Total securities available for sale	258,045	242,022
Gross Unrealized Gains	97	19
Gross Unrealized Losses	(32,581)	(30,026)
Fair Value	$ 225,561	$ 212,015