Securities - Amortized Cost and Fair Value of Securities with Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 443,254	$ 433,962
Gross Unrealized Gains	46	3,032
Gross Unrealized Losses	(47,815)	(7,063)
Fair Value	395,485	429,931
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	105,219	90,775
Gross Unrealized Losses	(10,057)	(1,598)
Fair Value	95,162	89,177
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	154,905	159,673
Gross Unrealized Gains		695
Gross Unrealized Losses	(16,885)	(3,482)
Fair Value	138,020	156,886
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	104,242	118,550
Gross Unrealized Gains		839
Gross Unrealized Losses	(13,978)	(1,462)
Fair Value	90,264	117,927
State and Local Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	78,888	64,964
Gross Unrealized Gains	46	1,498
Gross Unrealized Losses	(6,895)	(521)
Fair Value	$ 72,039	$ 65,941