Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands		12 Months Ended
Jan. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period		$ 301,187	$ 359,431	$ 209,096
Provision (benefit) charged to expense		272,797	(54,415)	137,848
Losses charged off		(87,522)	(18,654)	(55,333)
Recoveries		20,234	14,825	10,252
Specific reserves for TDR included in the balance of ALLL		594,741	301,187	359,431
Individually evaluated for impairment		47,234	21,073	16,137
Collectively evaluated for impairment		547,507	280,114	343,294
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase		88,045	0	0
Sterling \| Financial Asset Acquired with Credit Deterioration
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss, Writeoff	$ 48,300
Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss		0		57,568	$ 0
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period		43,310	47,187	47,427
Provision (benefit) charged to expense		4,502	(5,764)	(18,488)
Losses charged off		(4,662)	(9,217)	(12,408)
Recoveries		8,797	11,104	7,112
Specific reserves for TDR included in the balance of ALLL		61,616	43,310	47,187
Individually evaluated for impairment		12,441	4,108	4,450
Collectively evaluated for impairment		49,175	39,202	42,737
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase		9,669	0	0
Consumer \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss		0		23,544	0
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period		257,877	312,244	161,669
Provision (benefit) charged to expense		268,295	(48,651)	156,336
Losses charged off		(82,860)	(9,437)	(42,925)
Recoveries		11,437	3,721	3,140
Specific reserves for TDR included in the balance of ALLL		533,125	257,877	312,244
Individually evaluated for impairment		34,793	16,965	11,687
Collectively evaluated for impairment		498,332	240,912	300,557
Financing Receivable, Allowance for Credit Loss, Purchased with Credit Deterioration, Increase		78,376	$ 0	0
Commercial \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Financing Receivable, Allowance for Credit Loss		$ 0		$ 34,024	$ 0

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 increase in allowance for credit loss on financing receivable purchased with credit deterioration.

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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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Amount of writeoff of financing receivable, charged against allowance for credit loss.

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

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