Securities - Summary of Gross Unrealized Losses and Fair Value of Available for Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Held-to-maturity, Gross Unrealized Losses, Total	$ (42,810)	$ (35,448)
Gross Unrealized Losses, Less Than 12 Months	(692)	(12,931)
Fair Value, Less Than 12 Months	23,665	135,499
Gross Unrealized Losses, 12 Months Or More	(58,478)	(37,225)
Fair Value, 12 Months Or More	308,936	217,374
Gross Unrealized Losses, Total	(59,170)	(50,156)
Fair Value, Total	332,601	352,873
U.S. Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Gross Unrealized Losses, Less Than 12 Months		(798)
Available-for-sale, Fair Value, Less Than 12 Months		17,405
Available-for-sale, Gross Unrealized Losses, 12 Months or More	(675)	(171)
Available-for-sale, Fair Value, 12 Months or More	22,458	4,820
Available-for-sale, Gross Unrealized Losses, Total	(675)	(969)
Available-for-sale, Fair Value, Total	22,458	22,225
Held-to-maturity, Gross Unrealized Losses, 12 Months Or More	(1,083)	(1,136)
Held-to-maturity, Fair Value, 12 Months Or More	9,209	11,617
Held-to-maturity, Gross Unrealized Losses, Total	(1,083)	(1,136)
Held-to-maturity, Fair Value, Total	9,209	11,617
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Gross Unrealized Losses, 12 Months or More	(1,151)	(1,369)
Available-for-sale, Fair Value, 12 Months or More	12,848	12,630
Available-for-sale, Gross Unrealized Losses, Total	(1,151)	(1,369)
Available-for-sale, Fair Value, Total	12,848	12,630
Mortgage-Backed Securities of Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Gross Unrealized Losses, Less Than 12 Months	(235)	(1,046)
Available-for-sale, Fair Value, Less Than 12 Months	12,748	16,188
Available-for-sale, Gross Unrealized Losses, 12 Months or More	(9,773)	(7,813)
Available-for-sale, Fair Value, 12 Months or More	51,513	44,519
Available-for-sale, Gross Unrealized Losses, Total	(10,008)	(8,859)
Available-for-sale, Fair Value, Total	64,261	60,707
Held-to-maturity, Gross Unrealized Losses, Less Than 12 Months	(356)	(9,733)
Held-to-maturity, Fair Value, Less Than 12 Months	8,080	79,325
Held-to-maturity, Gross Unrealized Losses, 12 Months Or More	(40,978)	(24,318)
Held-to-maturity, Fair Value, 12 Months Or More	168,233	118,692
Held-to-maturity, Gross Unrealized Losses, Total	(41,334)	(34,051)
Held-to-maturity, Fair Value, Total	176,313	198,017
Asset-Backed Securities of Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Gross Unrealized Losses, 12 Months or More	(17)	(15)
Available-for-sale, Fair Value, 12 Months or More	552	618
Available-for-sale, Gross Unrealized Losses, Total	(17)	(15)
Available-for-sale, Fair Value, Total	552	618
State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Gross Unrealized Losses, Less Than 12 Months	(79)	(189)
Available-for-sale, Fair Value, Less Than 12 Months	1,952	9,079
Available-for-sale, Gross Unrealized Losses, 12 Months or More	(1,494)	(796)
Available-for-sale, Fair Value, 12 Months or More	16,622	9,848
Available-for-sale, Gross Unrealized Losses, Total	(1,573)	(985)
Available-for-sale, Fair Value, Total	18,574	18,927
Held-to-maturity, Gross Unrealized Losses, Less Than 12 Months	(21)
Held-to-maturity, Fair Value, Less Than 12 Months	393
Held-to-maturity, Gross Unrealized Losses, 12 Months Or More	(372)	(261)
Held-to-maturity, Fair Value, 12 Months Or More	1,771	1,903
Held-to-maturity, Gross Unrealized Losses, Total	(393)	(261)
Held-to-maturity, Fair Value, Total	2,164	1,903
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Gross Unrealized Losses, Less Than 12 Months	(1)	(1,165)
Available-for-sale, Fair Value, Less Than 12 Months	492	13,502
Available-for-sale, Gross Unrealized Losses, 12 Months or More	(2,935)	(1,346)
Available-for-sale, Fair Value, 12 Months or More	25,730	12,727
Available-for-sale, Gross Unrealized Losses, Total	(2,936)	(2,511)
Available-for-sale, Fair Value, Total	$ 26,222	$ 26,229