Loans and Leases (Summary Of Loan And Lease Portfolio Aging By Class Of Loan) (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 198,562	$ 189,199
Financing Receivable, 90 Days or More Past Due, Still Accruing	92	104
Financing Receivable, Nonaccrual	162,899	154,767
Financing Receivable, Not Past Due	19,353,084	18,276,290
Loans and leases	19,551,646	18,465,489	$ 18,321,019
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	24,741	22,333
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	10,830	11,995
Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans and leases	6,488,056	6,216,606	6,174,396
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	62,052	57,627
Financing Receivable, 90 Days or More Past Due, Still Accruing	92	104
Financing Receivable, Nonaccrual	58,750	55,810
Financing Receivable, Not Past Due	5,303,238	5,189,808
Loans and leases	5,365,290	5,247,435
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,760	1,011
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	450	702
Commercial Portfolio Segment [Member] \| Asset Based Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	9,162	224
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	9,162	224
Financing Receivable, Not Past Due	1,113,604	968,947
Loans and leases	1,122,766	969,171
Commercial Portfolio Segment [Member] \| Asset Based Loans [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial Portfolio Segment [Member] \| Asset Based Loans [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans and leases	5,398,084	4,927,145	4,771,325
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,968	0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	2,968	0
Financing Receivable, Not Past Due	295,860	218,831
Loans and leases	298,828	218,831
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	11,289	9,762
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	9,852	8,242
Financing Receivable, Not Past Due	5,087,967	4,698,552
Loans and leases	5,099,256	4,708,314
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,296	1,275
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	141	245
Finance Leases Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	7,679	7,229
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	5,488	6,314
Financing Receivable, Not Past Due	514,149	501,168
Loans and leases	521,828	508,397	519,054
Finance Leases Portfolio Segment [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,666	510
Finance Leases Portfolio Segment [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	525	405
Residential Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	57,318	62,002
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	43,839	49,188
Financing Receivable, Not Past Due	4,816,408	4,354,635
Loans and leases	4,873,726	4,416,637	4,415,063
Residential Portfolio Segment [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	6,752	8,513
Residential Portfolio Segment [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	6,727	4,301
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans and leases	2,269,952	2,396,704	$ 2,441,181
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	42,934	48,130
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	31,452	33,495
Financing Receivable, Not Past Due	2,007,428	2,121,049
Loans and leases	2,050,362	2,169,179
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	9,192	9,250
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,290	5,385
Consumer Portfolio Segment [Member] \| Consumer Borrower [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	5,160	4,225
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	1,388	1,494
Financing Receivable, Not Past Due	214,430	223,300
Loans and leases	219,590	227,525
Consumer Portfolio Segment [Member] \| Consumer Borrower [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,075	1,774
Consumer Portfolio Segment [Member] \| Consumer Borrower [Member] \| Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 697	$ 957

Amount of financing receivable 90 days or more past due and still accruing.

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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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