Securities - Amortized Cost and Fair Value of Securities with Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 408,697	$ 439,186
Gross Unrealized Gains	69	69
Gross Unrealized Losses	(45,541)	(48,466)
Fair Value	363,225	390,789
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	95,034	104,507
Gross Unrealized Losses	(8,907)	(9,829)
Fair Value	86,127	94,678
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	144,048	156,817
Gross Unrealized Losses	(16,157)	(17,050)
Fair Value	127,891	139,767
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	95,366	101,068
Gross Unrealized Losses	(13,710)	(14,141)
Fair Value	81,656	86,927
State and Local Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	74,249	76,794
Gross Unrealized Gains	69	69
Gross Unrealized Losses	(6,767)	(7,446)
Fair Value	$ 67,551	$ 69,417