Loans and Leases (Interest Income From Impaired Loans And Leases, By Class) (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 264,162	$ 305,015	$ 339,477
Accrued Interest Income	8,065	8,557	12,180
Cash Basis Interest Income	2,185	2,238	2,424
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	126,936	138,215	142,198
Accrued Interest Income	4,377	4,473	4,644
Cash Basis Interest Income	1,200	1,139	1,221
Consumer Portfolio Segment [Member] \| Home Equity Loan [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	47,072	49,337	51,171
Accrued Interest Income	1,361	1,451	1,484
Cash Basis Interest Income	985	1,099	1,203
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	3,574	6,062	8,381
Accrued Interest Income	92	133	269
Cash Basis Interest Income	0	0	0
Finance Leases Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	3,421	527	421
Accrued Interest Income	184	16	28
Cash Basis Interest Income	0	0	0
Commercial and Industrial Sector [Member] \| Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	54,708	46,379	44,097
Accrued Interest Income	1,540	1,319	2,326
Cash Basis Interest Income	0	0	0
Commercial Real Estate [Member] \| Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	28,451	64,495	93,209
Accrued Interest Income	511	1,165	3,429
Cash Basis Interest Income	$ 0	$ 0	$ 0

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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://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&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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