Loans and Leases (Summary Of Loan And Lease Portfolio Aging By Class Of Loan) (Detail) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 180,686	$ 189,199
Financing Receivable, 90 Days or More Past Due, Still Accruing	410	104
Financing Receivable, Nonaccrual	148,301	154,767
Financing Receivable, Not Past Due	19,089,197	18,276,290
Loans and leases	19,269,883	18,465,489	$ 18,025,996
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	23,234	22,333
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	8,741	11,995
Residential Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	59,105	62,002
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	48,228	49,188
Financing Receivable, Not Past Due	4,659,599	4,354,635
Loans and leases	4,718,704	4,416,637	4,455,580
Residential Portfolio Segment [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	6,922	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	3,955	4,301
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans and leases	2,301,291	2,396,704	2,485,695
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	41,895	48,130
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	31,870	33,495
Financing Receivable, Not Past Due	2,035,234	2,121,049
Loans and leases	2,077,129	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	7,451	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	2,574	5,385
Consumer Portfolio Segment [Member] \| Consumer Borrower [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	5,146	4,225
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	1,190	1,494
Financing Receivable, Not Past Due	219,016	223,300
Loans and leases	224,162	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	2,776	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	1,180	957
Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Loans and leases	6,519,953	6,216,606	5,981,556
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	54,850	57,627
Financing Receivable, 90 Days or More Past Due, Still Accruing	410	104
Financing Receivable, Nonaccrual	52,452	55,810
Financing Receivable, Not Past Due	5,387,985	5,189,808
Loans and leases	5,442,835	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	1,300	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	688	702
Commercial Portfolio Segment [Member] \| Asset Based Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	184	224
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	184	224
Financing Receivable, Not Past Due	1,076,934	968,947
Loans and leases	1,077,118	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	5,224,382	4,927,145	4,580,200
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,355	0
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	0	0
Financing Receivable, Not Past Due	253,713	218,831
Loans and leases	255,068	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	1,355	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	11,742	9,762
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	10,428	8,242
Financing Receivable, Not Past Due	4,957,572	4,698,552
Loans and leases	4,969,314	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	1,189	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	125	245
Finance Leases Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	6,409	7,229
Financing Receivable, 90 Days or More Past Due, Still Accruing	0	0
Financing Receivable, Nonaccrual	3,949	6,314
Financing Receivable, Not Past Due	499,144	501,168
Loans and leases	505,553	508,397	$ 522,965
Finance Leases Portfolio Segment [Member] \| Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,241	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	$ 219	$ 405

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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