Loans (Modification to Borrowers Experiencing Financial Difficulty) (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 18,824,251	$ 17,154,969
Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0	$ 1,051
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	$ 33,251	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.20%	0.00%
Extended Maturity and Interest Rate Reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 2,092	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%
Commercial Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 5,959,133	$ 5,674,798
Commercial Portfolio Segment [Member] \| Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%
Commercial Portfolio Segment [Member] \| Combination: Payment Delay and Term Extention
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 13,813
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	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
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%
Commercial Real Estate, Buildings, Land and Other [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 7,301,920	6,706,078
Commercial Real Estate, Buildings, Land and Other [Member] \| Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Loans, net of unearned discounts	$ 0	$ 1,051
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	$ 19,438	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.30%	0.00%
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	$ 2,092	$ 0
Financing Receivable, Modified in Period, to Total Financing Receivables, Percentage	0.00%	0.00%

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