Investment Securities - Summary of Contractual Maturities of Investment Securities Classified as Available for Sale and Held to Maturity (Detail) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Available for Sale, Amortized Cost
Due in one year or less	$ 151,972
Due after one year through five years	143,867
Due after five years through ten years	106,678
Due after ten years	53,353
Total	455,870
Total	1,004,333	$ 1,035,238
Available for Sale, Fair Value
Due in one year or less	148,067
Due after one year through five years	132,305
Due after five years through ten years	92,296
Due after ten years	47,727
Total	420,395
Total	914,029	946,282
Held to Maturity, Amortized Cost
Due in one year or less	25,668
Due after one year through five years	32,891
Due after five years through ten years	111,040
Due after ten years	314,718
Total	484,317
Amortized Cost	827,253	836,523
Held to Maturity, Fair Value
Due in one year or less	25,508
Due after one year through five years	30,830
Due after five years through ten years	94,807
Due after ten years	249,215
Total	400,360
Total	681,857	$ 702,563
Mortgage-backed and asset-backed securities
Available for Sale, Amortized Cost
Mortgage-backed and asset-backed securities	548,463
Available for Sale, Fair Value
Mortgage-backed and asset-backed securities	493,634
Held to Maturity, Amortized Cost
Mortgage-backed and asset-backed securities	342,936
Held to Maturity, Fair Value
Mortgage-backed and asset-backed securities	$ 281,497