Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands		3 Months Ended
Jan. 31, 2022	Mar. 31, 2022	Mar. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period		$ 301,187	$ 359,431
Initial allowance for PCD loans and leases		88,045	0
Provision (benefit)		189,068	(25,759)
Charge-offs		(12,368)	(9,295)
Recoveries		3,439	3,974
Balance, end of period		569,371	328,351
ALLL, Individually evaluated for impairment		44,793	19,722
ALLL, Collectively evaluated for impairment		524,578	308,629
PCD loans \| Sterling
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Charge-offs	$ (48,300)
Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period		257,877	312,244
Initial allowance for PCD loans and leases		78,376	0
Provision (benefit)		184,327	(23,653)
Charge-offs		(11,248)	(6,321)
Recoveries		1,364	1,636
Balance, end of period		510,696	283,906
ALLL, Individually evaluated for impairment		32,736	14,809
ALLL, Collectively evaluated for impairment		477,960	269,097
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period		43,310	47,187
Initial allowance for PCD loans and leases		9,669	0
Provision (benefit)		4,741	(2,106)
Charge-offs		(1,120)	(2,974)
Recoveries		2,075	2,338
Balance, end of period		58,675	44,445
ALLL, Individually evaluated for impairment		12,057	4,913
ALLL, Collectively evaluated for impairment		$ 46,618	$ 39,532

Amount excluding accrued interest, of allowance for credit loss on financing receivable.

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

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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

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