Loans and Leases (Interest Income From Impaired Loans And Leases, By Class) (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 257,870	$ 253,042	$ 248,054
Accrued Interest Income	8,173	8,313	7,192
Cash Basis Interest Income	2,059	2,086	2,310
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	96,814	108,913	116,859
Accrued Interest Income	3,502	3,781	4,138
Cash Basis Interest Income	1,078	1,106	1,264
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	37,167	42,290	45,578
Accrued Interest Income	1,045	1,158	1,323
Cash Basis Interest Income	981	980	1,046
Commercial Portfolio Segment [Member] \| Commercial and Industrial Sector [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	100,771	85,585	62,459
Accrued Interest Income	3,241	3,064	1,095
Commercial Portfolio Segment [Member] \| Asset Based Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	182	407	295
Accrued Interest Income	0	0	0
Commercial Real Estate Portfolio Segment [Member] \| Real Estate [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	16,256	11,027	17,397
Accrued Interest Income	385	198	417
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	806	0	594
Accrued Interest Income	0	0	12
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	5,874	4,820	4,872
Accrued Interest Income	$ 0	$ 112	$ 207

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- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=118936363&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

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