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Securities - Amortized Cost and Fair Value of Debt Securities, by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Available-for-Sale Securities, Debt Maturities [Abstract]
Amortized Cost, One year or less	$ 65,422
Amortized Cost, After one year through five years	218,041
Amortized Cost, After five years through ten years	11,905
Amortized Cost, Total	295,368
Amortized Cost, Mortgage-backed securities	145,110
Amortized Cost	440,478	$ 458,484
Fair Value, One year or less	64,557
Fair Value, After one year through five years	209,021
Fair Value, After five years through ten years	11,572
Fair Value, Total	285,150
Fair Value, Mortgage-backed securities	137,623
Total, Fair Value	$ 422,773	$ 426,556

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