Securities - Gross Unrealized Losses, Aggregated by Investment Category and Length of Time (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	$ (201)	$ (26)
Fair Value, Less Than Twelve Months	19,576	5,797
Gross Unrealized Losses, Twelve Months and Over	(36,041)	(36,835)
Fair Value, Twelve Months and Over	333,026	345,911
Gross Unrealized Losses, Total	(36,242)	(36,861)
Fair Value, Total	352,602	351,708
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(4)	(4)
Fair Value, Less Than Twelve Months	562	494
Gross Unrealized Losses, Twelve Months and Over	(6,580)	(6,909)
Fair Value, Twelve Months and Over	74,552	79,528
Gross Unrealized Losses, Total	(6,584)	(6,913)
Fair Value, Total	75,114	80,022
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Twelve Months and Over	(12,324)	(12,738)
Fair Value, Twelve Months and Over	128,571	128,222
Gross Unrealized Losses, Total	(12,324)	(12,738)
Fair Value, Total	128,571	128,222
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(132)	(20)
Fair Value, Less Than Twelve Months	15,445	4,372
Gross Unrealized Losses, Twelve Months and Over	(11,922)	(11,909)
Fair Value, Twelve Months and Over	72,400	77,759
Gross Unrealized Losses, Total	(12,054)	(11,929)
Fair Value, Total	87,845	82,131
State and Local Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(65)	(2)
Fair Value, Less Than Twelve Months	3,569	931
Gross Unrealized Losses, Twelve Months and Over	(5,215)	(5,279)
Fair Value, Twelve Months and Over	57,503	60,402
Gross Unrealized Losses, Total	(5,280)	(5,281)
Fair Value, Total	$ 61,072	$ 61,333