Securities - Amortized Cost and Fair Value of Securities with Gross Unrealized Gains and Losses (Detail) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 438,966	$ 433,962
Gross Unrealized Gains	287	3,032
Gross Unrealized Losses	(25,257)	(7,063)
Fair Value	413,996	429,931
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	105,394	90,775
Gross Unrealized Losses	(5,849)	(1,598)
Fair Value	99,545	89,177
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	153,575	159,673
Gross Unrealized Gains	50	695
Gross Unrealized Losses	(9,818)	(3,482)
Fair Value	143,807	156,886
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	111,516	118,550
Gross Unrealized Gains	43	839
Gross Unrealized Losses	(6,499)	(1,462)
Fair Value	105,060	117,927
State and Local Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	68,481	64,964
Gross Unrealized Gains	194	1,498
Gross Unrealized Losses	(3,091)	(521)
Fair Value	$ 65,584	$ 65,941