Loans and Leases - Narrative (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2025	Dec. 31, 2024
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized premiums	$ 9,200	$ (1,800)
Interest receivable	269,300	265,000
Loans and leases, net	$ 52,342,902	$ 51,815,602
Commercial real estate \| Customer Concentration Risk \| Loans and Finance Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk	40.30%	40.70%
Commercial non-mortgage \| Customer Concentration Risk \| Loans and Finance Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Concentration of credit risk	34.40%	34.40%
Commercial non-mortgage \| Term Extension
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified loans	$ 17,800
Collateral Pledged \| Commercial portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment	228,400	$ 139,500
Collateral Pledged \| Consumer portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment	26,600	29,100
Collateral Pledged \| Asset Pledged as Collateral \| Federal Home Loan Bank Certificates and Obligations (FHLB)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net	17,700,000
Collateral Pledged \| Asset Pledged as Collateral \| Federal Reserve Bank Certificates And Obligations (FRB)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases, net	5,100,000
Collateral Value
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment	$ 253,000	$ 200,100

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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