Securities - Securities with Unrealized Losses Not Recognized in Income (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	$ 302,275	$ 208,556
12 Months or less, Unrealized Loss	(18,609)	(1,923)
More than 12 months, Fair Value	238,156	5,137
More than 12 months, Unrealized Loss	(49,159)	(164)
Total Fair Value	540,431	213,693
Total Unrealized Loss	(67,768)	(2,087)
U.S. Treasury Securities and Obligations of U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	21,042	41,432
12 Months or less, Unrealized Loss	(880)	(473)
More than 12 months, Fair Value	39,567	2,014
More than 12 months, Unrealized Loss	(4,606)	(57)
Total Fair Value	60,609	43,446
Total Unrealized Loss	(5,486)	(530)
Obligations of States and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	169,594	25,797
12 Months or less, Unrealized Loss	(13,016)	(107)
More than 12 months, Fair Value	73,967
More than 12 months, Unrealized Loss	(20,624)
Total Fair Value	243,561	25,797
Total Unrealized Loss	(33,640)	(107)
Mortgage-backed Securities in Government Sponsored Entities [Member]
Schedule of Available-for-sale Securities [Line Items]
12 Months or less, Fair Value	111,639	141,327
12 Months or less, Unrealized Loss	(4,713)	(1,343)
More than 12 months, Fair Value	124,622	3,123
More than 12 months, Unrealized Loss	(23,929)	(107)
Total Fair Value	236,261	144,450
Total Unrealized Loss	$ (28,642)	$ (1,450)