Investment Securities - Summary of Investments Classified by Contractual Maturity Date (Detail) $ in Thousands	Sep. 30, 2020 USD ($)
Schedule Of Investments [Abstract]
Securities Available for Sale, Amortized Cost, Due in one year or less	$ 925
Securities Available for Sale, Amortized Cost, Due after one year through five years	71,574
Securities Available for Sale, Amortized Cost, Due after five years through ten years	33,608
Securities Available for Sale, Amortized Cost, Due after ten years	7,378
Securities Available for Sale, Amortized Cost, Total	113,485
Securities Available for Sale, Fair Value, Due in one year or less	927
Securities Available for Sale, Fair Value, Due after one year through five years	72,137
Securities Available for Sale, Fair Value, Due after five years through ten years	33,324
Securities Available for Sale, Fair Value, Due after ten years	7,501
Securities Available for Sale, Fair Value, Total	$ 113,889

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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