Investment Securities (Securities Held to Maturity by Contractual Maturity) (Detail) $ in Thousands	Mar. 31, 2022 USD ($)
Investments, Debt and Equity Securities [Abstract]
Due in one year or less, amortized cost	$ 17,286
Due after one year through five years, amortized cost	153,590
Due after five years through ten years, amortized cost	194,905
Due after ten years, amortized cost	56,198
Amortized cost	421,979
Due in one year or less, fair value	17,338
Due after one year through five years, fair value	152,915
Due after five years through ten years, fair value	194,739
Due after ten years, fair value	52,659
Fair value	$ 417,651

Fair value of investment in debt security measured at amortized cost (held-to-maturity), 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 amortized cost (held-to-maturity), 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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