Investment Securities - Summary of Contractual Maturities of Investment Securities Classified as Available for Sale and Held to Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Available for Sale, Amortized Cost
Due in one year or less	$ 43,295
Due after one year through five years	245,438
Due after five years through ten years	148,560
Due after ten years	60,142
Total	497,435
Total	1,094,955	$ 1,158,534
Available for Sale, Fair Value
Due in one year or less	42,447
Due after one year through five years	228,532
Due after five years through ten years	127,771
Due after ten years	54,414
Total	453,164
Total	988,973	1,054,312
Held to Maturity, Amortized Cost
Due in one year or less	40,956
Due after one year through five years	34,856
Due after five years through ten years	85,531
Due after ten years	353,066
Total	514,409
Amortized Cost	879,252	923,415
Held to Maturity, Fair Value
Due in one year or less	40,835
Due after one year through five years	32,895
Due after five years through ten years	73,664
Due after ten years	278,087
Total	425,481
Total	730,805	$ 760,455
Mortgage-backed and asset-backed securities
Available for Sale, Amortized Cost
Mortgage-backed and asset-backed securities	597,520
Available for Sale, Fair Value
Mortgage-backed and asset-backed securities	535,809
Held to Maturity, Amortized Cost
Mortgage-backed and asset-backed securities	364,843
Held to Maturity, Fair Value
Mortgage-backed and asset-backed securities	$ 305,324