Loans (Recorded Investment By Loan Class In Current And Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	$ 5,394	$ 6,522
Nonaccrual	7,842	12,520
Current	2,933,432	2,675,880
Total loans	2,946,668	2,694,922	$ 2,577,068
30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	4,781	5,357
60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	605	1,154
Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	8	11
Commercial Business [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	364	100
Nonaccrual	2,203	5,344
Current	534,593	444,319
Total loans	537,160	449,763	418,873
Commercial Business [Member] \| 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	364	64
Commercial Business [Member] \| 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans		36
Commercial Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	916	431
Nonaccrual	1,900	2,623
Current	904,291	807,797
Total loans	907,107	810,851	759,898
Commercial Mortgage [Member] \| 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	916	56
Commercial Mortgage [Member] \| 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans		375
Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	926	1,964
Nonaccrual	2,057	2,252
Current	495,900	453,545
Total loans	498,883	457,761	438,936
Residential Real Estate Loans [Member] \| 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	871	1,908
Residential Real Estate Loans [Member] \| 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	55	56
Residential Real Estate Lines [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	185	349
Nonaccrual	297	404
Current	107,745	112,669
Total loans	108,227	113,422	114,747
Residential Real Estate Lines [Member] \| 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	185	349
Consumer Indirect [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	2,871	3,478
Nonaccrual	1,385	1,895
Current	874,060	840,309
Total loans	878,316	845,682	827,154
Consumer Indirect [Member] \| 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	2,327	2,806
Consumer Indirect [Member] \| 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	544	672
Other Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	132	200
Nonaccrual		2
Current	16,843	17,241
Total loans	16,975	17,443	$ 17,460
Other Consumer [Member] \| 30 to 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	118	174
Other Consumer [Member] \| 60 to 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	6	15
Other Consumer [Member] \| Greater than 90 Days [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due Loans	$ 8	$ 11

Financing receivables that are current.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 310
-SubTopic 10
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
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