Loans and Leases (Allowance For Loan And Lease Losses By Portfolio Segment) (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	Jan. 31, 2022	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				$ 594,741	$ 301,187
Initial allowance for PCD loans and leases				0	88,045
Provision (benefit)		$ 35,249	$ 11,728	73,070	200,796
Charge-offs		(23,030)	(19,653)	(50,538)	(32,021)
Recoveries		2,778	10,053	5,765	13,492
Balance, end of period		628,911	571,499	628,911	571,499		$ 594,741		$ 301,187
ALLL, Individually evaluated for impairment		53,728	43,297	53,728	43,297
ALLL, Collectively evaluated for impairment		575,183	528,202	575,183	528,202
Balance, end of period		628,911	571,499	628,911	571,499	$ 613,914		$ 569,371
Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, end of period							5,873		0
PCD loans | Sterling
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Charge-offs	$ (48,300)
Commercial Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				533,125	257,877
Initial allowance for PCD loans and leases				0	78,376
Provision (benefit)		38,824	12,041	77,581	196,368
Charge-offs		(21,945)	(18,757)	(48,355)	(30,005)
Recoveries		1,024	7,765	2,598	9,129
Balance, end of period		572,653	511,745	572,653	511,745		533,125		257,877
ALLL, Individually evaluated for impairment		46,215	38,847	46,215	38,847
ALLL, Collectively evaluated for impairment		526,438	472,898	526,438	472,898
Balance, end of period		572,653	511,745	572,653	511,745	554,750		510,696
Commercial Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, end of period							7,704		0
Consumer Portfolio Segment [Member]
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period				61,616	43,310
Initial allowance for PCD loans and leases				0	9,669
Provision (benefit)		(3,575)	(313)	(4,511)	4,428
Charge-offs		(1,085)	(896)	(2,183)	(2,016)
Recoveries		1,754	2,288	3,167	4,363
Balance, end of period		56,258	59,754	56,258	59,754		61,616		43,310
ALLL, Individually evaluated for impairment		7,513	4,450	7,513	4,450
ALLL, Collectively evaluated for impairment		48,745	55,304	48,745	55,304
Balance, end of period		$ 56,258	$ 59,754	$ 56,258	$ 59,754	$ 59,164		$ 58,675
Consumer Portfolio Segment [Member] | Cumulative Effect, Period of Adoption, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance, end of period							$ (1,831)		$ 0