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Loans (Modification to Borrowers Experiencing Financial Difficulty) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 20,754,813	$ 18,824,251
Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 8,138	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 45,835	$ 33,251
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.20%	0.20%
Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 31,302	$ 2,092
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.20%	0.00%
Commercial Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 6,109,532	$ 5,967,182
Commercial Portfolio Segment [Member] | Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 6,126	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.10%	0.00%
Commercial Portfolio Segment [Member] | Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 45,835	$ 13,813
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.80%	0.20%
Commercial Portfolio Segment [Member] | Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 7,704,447	$ 7,301,920
Commercial Real Estate, Buildings, Land and Other [Member] | Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 2,012	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Commercial Real Estate, Buildings, Land and Other [Member] | Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0	$ 19,438
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.30%
Commercial Real Estate, Buildings, Land and Other [Member] | Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 31,302	$ 2,092
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.40%	0.00%

X

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

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Percentage of financing receivable modified during period for debtor experiencing financial difficulty to total financing receivables.

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