Investments - Summary of Gross Unrealized or Unrecognized Losses and Fair Value of Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	$ 33,708	$ 24,282
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	(159)	(787)
Total, Available-for-sale securities, 12 Months or More, Fair Value	583,201	606,838
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(61,280)	(80,735)
Total, Available-for-sale securities, Fair Value	616,909	631,120
Total, Available-for-sale securities, Unrecognized Loss	(61,439)	(81,522)
Total, Held-to-maturity securities, Less Than 12 Months, Fair Value	172
Total, Held-to-maturity securities, Less Than 12 Months, Unrecognized Loss	(1)
Total, Held-to-maturity securities, Fair Value	172
Total, Held-to-maturity securities, Unrecognized Loss	(1)
U.S. Government Sponsored Entities [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	0
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	0
Total, Available-for-sale securities, 12 Months or More, Fair Value	33,644	33,087
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(4,846)	(6,016)
Total, Available-for-sale securities, Fair Value	33,644	33,087
Total, Available-for-sale securities, Unrecognized Loss	(4,846)	(6,016)
U.S. Treasury securities [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	0	0
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	0
Total, Available-for-sale securities, 12 Months or More, Fair Value	19,813	19,413
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(248)	(771)
Total, Available-for-sale securities, Fair Value	19,813	19,413
Total, Available-for-sale securities, Unrecognized Loss	(248)	(771)
Government-Sponsored Residential Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	24,152	7,799
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	(99)	(5)
Total, Available-for-sale securities, 12 Months or More, Fair Value	284,249	306,858
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(26,722)	(35,398)
Total, Available-for-sale securities, Fair Value	308,401	314,657
Total, Available-for-sale securities, Unrecognized Loss	(26,821)	(35,403)
Private Label Residential Mortgage-Backed Securities [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, 12 Months or More, Fair Value	130,403	137,841
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(17,714)	(23,333)
Total, Available-for-sale securities, Fair Value	130,403	137,841
Total, Available-for-sale securities, Unrecognized Loss	(17,714)	(23,333)
Corporate [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	3,213
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	(48)
Total, Available-for-sale securities, 12 Months or More, Fair Value	46,684	49,683
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(3,772)	(7,039)
Total, Available-for-sale securities, Fair Value	49,897	49,683
Total, Available-for-sale securities, Unrecognized Loss	(3,820)	(7,039)
Small Business Administration Loan Pools [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	4,156	5,097
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	0	(14)
Total, Available-for-sale securities, 12 Months or More, Fair Value	2,405	2,630
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(231)	(325)
Total, Available-for-sale securities, Fair Value	6,561	7,727
Total, Available-for-sale securities, Unrecognized Loss	(231)	(339)
State and Political Subdivisions [Member]
Schedule of Investments [Line Items]
Total, Available-for-sale securities, Less Than 12 Months, Fair Value	2,187	11,386
Total, Available-for-sale securities, Less Than 12 Months, Unrecognized Loss	(12)	(768)
Total, Available-for-sale securities, 12 Months or More, Fair Value	66,003	57,326
Total, Available-for-sale securities, 12 Months or More, Unrecognized Loss	(7,747)	(7,853)
Total, Available-for-sale securities, Fair Value	68,190	68,712
Total, Available-for-sale securities, Unrecognized Loss	(7,759)	$ (8,621)
Total, Held-to-maturity securities, Less Than 12 Months, Fair Value	172
Total, Held-to-maturity securities, Less Than 12 Months, Unrecognized Loss	(1)
Total, Held-to-maturity securities, Fair Value	172
Total, Held-to-maturity securities, Unrecognized Loss	$ (1)