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Allowance for Credit Losses (Summary of Loans Experiencing Financial Difficulties Subsequently Defaulted) (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms		$ 45,792
Payments in Default
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms	$ 20,407	20,407
Commercial | Commercial, industrial and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms		37,897
Commercial | Commercial, industrial and other | Payments in Default
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms	18,729	18,729
Commercial real estate | Non-construction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms		5,709
Commercial real estate | Non-construction | Payments in Default
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms	923	923
Home equity | Commercial, industrial and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms		203
Home equity | Commercial, industrial and other | Payments in Default
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms	203	203
Residential real estate | Commercial, industrial and other
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms		1,972
Residential real estate | Commercial, industrial and other | Payments in Default
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms	541	541
Premium finance receivables | Property and casualty insurance loans
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms		11
Premium finance receivables | Property and casualty insurance loans | Payments in Default
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans in payment default under restructured terms	$ 11	$ 11

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
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-Publisher FASB
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Section 50
-Paragraph 42
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-Publisher FASB
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Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481933/310-10-55-12A

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-33

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
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-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-34

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