Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 01, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 359,431	$ 209,096	$ 212,353
Provision (benefit) charged to expense	(54,415)	137,848	37,800
Losses charged off	(18,654)	(55,333)	(52,480)
Recoveries	14,825	10,252	11,423
Specific reserves for TDR included in the balance of ALLL	301,187	359,431	209,096
Individually evaluated for impairment	21,073	16,137	14,249
Collectively evaluated for impairment	280,114	343,294	194,847
Loans and leases	22,271,729	21,641,215
Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss	0		0	$ 57,568
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	47,187	47,427	48,280
Provision (benefit) charged to expense	(5,764)	(18,488)	8,626
Losses charged off	(9,217)	(12,408)	(19,153)
Recoveries	11,104	7,112	9,674
Specific reserves for TDR included in the balance of ALLL	43,310	47,187	47,427
Individually evaluated for impairment	4,108	4,450	4,821
Collectively evaluated for impairment	39,202	42,737	42,606
Loans and leases	7,091,763
Consumer Portfolio Segment [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss	0		0	23,544
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	312,244	161,669	164,073
Provision (benefit) charged to expense	(48,651)	156,336	29,174
Losses charged off	(9,437)	(42,925)	(33,327)
Recoveries	3,721	3,140	1,749
Specific reserves for TDR included in the balance of ALLL	257,877	312,244	161,669
Individually evaluated for impairment	16,965	11,687	9,428
Collectively evaluated for impairment	240,912	$ 300,557	152,241
Loans and leases	15,179,966
Commercial Portfolio Segment [Member] \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss	$ 0		$ 0	$ 34,024

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The balance of financing receivables that were collectively evaluated for impairment.

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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related to estimated loss from loan and lease transactions.

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