Allowance for Credit Losses (Summary of Activity In Allowance for Loan and Lease Losses) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Allowance for Credit Loss [Line Items]
Forecast period (years)			2 years
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 210,651	$ 209,259	$ 224,314	$ 225,141
Provision (credit)	(19,603)	20,552	(30,577)	48,907
Initial allowance on PCD loans				1,193
Charge-offs	(7,528)	(12,064)	(16,091)	(26,325)
Recoveries	5,574	4,703	11,448	11,458
Ending balance	189,094	222,450	189,094	222,450
Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				(37,924)
Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				187,217
Commercial
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	74,864	72,410	80,842	142,369
Provision (credit)	3,279	6,628	(643)	28,165
Initial allowance on PCD loans				0
Charge-offs	(3,044)	(4,015)	(6,375)	(9,384)
Recoveries	983	1,154	2,258	2,581
Ending balance	76,082	76,177	76,082	76,177
Commercial \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				(87,554)
Commercial \| Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				54,815
Consumer
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	112,852	109,933	119,485	75,236
Provision (credit)	(17,481)	13,682	(22,985)	23,088
Initial allowance on PCD loans				0
Charge-offs	(4,028)	(6,657)	(8,497)	(14,426)
Recoveries	2,929	2,387	6,269	4,818
Ending balance	94,272	119,345	94,272	119,345
Consumer \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				30,629
Consumer \| Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				105,865
Unfunded Loan Commitment
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,571	10,512	12,814	1,055
Provision (credit)	(468)	3,173	(1,711)	3,745
Ending balance	11,103	13,685	11,103	13,685
Unfunded Loan Commitment \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0	0	8,885
Unfunded Loan Commitment \| Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,571	10,512	12,814	9,940
PCD Loans
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	22,935	26,916	23,987	7,536
Provision (credit)	(5,401)	242	(6,949)	(2,346)
Initial allowance on PCD loans				1,193
Charge-offs	(456)	(1,392)	(1,219)	(2,515)
Recoveries	1,662	1,162	2,921	4,059
Ending balance	$ 18,740	$ 26,928	$ 18,740	26,928
PCD Loans \| Cumulative Effect, Period of Adoption, Adjustment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				19,001
PCD Loans \| Cumulative Effect, Period of Adoption, Adjusted Balance [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance				$ 26,537

Financing Receivable, Allowance For Credit Loss, Forecast Period

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- Definition

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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

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

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Amount of allowance for credit loss at acquisition date of financing receivable purchased with credit deterioration.

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- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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