Investment Securities (Available for Sale by Contractual Maturity) (Detail) $ in Thousands	Mar. 31, 2022 USD ($)
Investments, Debt and Equity Securities [Abstract]
Due in one year or less, amortized cost	$ 997
Due after one year through five years, amortized cost	137,234
Due after five years through ten years, amortized cost	174,136
Due after ten years, amortized cost	65,050
Amortized cost	377,417
Due in one year or less, fair value	1,005
Due after one year through five years, fair value	130,466
Due after five years through ten years, fair value	164,946
Due after ten years, fair value	60,520
Fair value	$ 356,937

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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Fair value 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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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 second through fifth 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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Fair value 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 second through fifth 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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