Allowance for Credit Losses (Summary of Loans Restructured and Subsequently Defaulted Under the Restructured Terms) (Detail) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022 USD ($) contract	Mar. 31, 2021 USD ($) contract	Mar. 31, 2022 USD ($) contract	Mar. 31, 2021 USD ($) contract
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	13	20	57	106
TDRs, balance \| $	$ 3,097	$ 2,126	$ 14,839	$ 24,201
Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	14	13
TDRs, balance \| $	$ 6,793	$ 5,213
Commercial, industrial and other \| Commercial, industrial and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	3	2	17	18
TDRs, balance \| $	$ 282	$ 151	$ 5,205	$ 6,910
Commercial, industrial and other \| Commercial, industrial and other \| Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	11	5
TDRs, balance \| $	$ 4,526	$ 1,496
Commercial real estate \| Non-construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	2	2	5	7
TDRs, balance \| $	$ 1,907	$ 237	$ 4,613	$ 3,466
Commercial real estate \| Non-construction \| Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	2	3
TDRs, balance \| $	$ 2,163	$ 3,121
Residential real estate and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	8	16	35	81
TDRs, balance \| $	$ 908	$ 1,738	$ 5,021	$ 13,825
Residential real estate and other \| Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
TDRs, count \| contract	1	5
TDRs, balance \| $	$ 104	$ 596

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Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

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Amount, after troubled debt restructuring, of modified financing receivable.

+ References

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