Securities - Amortized Cost and Fair Value of Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Investments Debt And Equity Securities [Abstract]
Amortized Cost, Due in one year or less	$ 8,185
Amortized Cost, Due after one year through five years	17,501
Amortized Cost, Due after five years through ten years	26,404
Amortized Cost, Due after ten years	173,226
Amortized Cost, Mortgage-backed securities	118,322
Amortized Cost, Total securities available for sale	343,638	$ 342,192
Fair Value, Due in one year or less	8,252
Fair Value, Due after one year through five years	17,966
Fair Value, Due after five years through ten years	28,233
Fair Value, Due after ten years	189,368
Fair Value, Mortgage-backed securities	124,564
Fair Value, Total securities available for sale	$ 368,383	$ 358,499

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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