Investments (Aggregate Carrying And Approximate Market Values Of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 524,128	$ 453,697
Gross Unrealized Gains	7,395	5,488
Gross Unrealized Losses	5,890	9,102
Estimated Fair Value	525,633	450,083
U.S Treasuries and U.S. Government Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2	3
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	2	3
Obligations Of States And Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	95,907	83,248
Gross Unrealized Gains	1,835	594
Gross Unrealized Losses	574	1,474
Estimated Fair Value	97,168	82,368
U.S. Government Agencies Mortgage-backed Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	397,192	335,867
Gross Unrealized Gains	1,931	1,507
Gross Unrealized Losses	5,136	6,560
Estimated Fair Value	393,987	330,814
Private Label
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	687	941
Gross Unrealized Gains	3	1
Gross Unrealized Losses	0	0
Estimated Fair Value	690	942
Trust Preferred Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	4,761	6,052
Gross Unrealized Gains	183	1,164
Gross Unrealized Losses	0	554
Estimated Fair Value	4,944	6,662
Corporate Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	21,918	23,925
Gross Unrealized Gains	562	127
Gross Unrealized Losses	154	478
Estimated Fair Value	22,326	23,574
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	520,467	450,036
Gross Unrealized Gains	4,514	3,393
Gross Unrealized Losses	5,864	9,066
Estimated Fair Value	519,117	444,363
Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	2,136	2,136
Gross Unrealized Gains	2,881	2,095
Gross Unrealized Losses	0	0
Estimated Fair Value	5,017	4,231
Money Market Funds
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,525	1,525
Gross Unrealized Gains	0	0
Gross Unrealized Losses	26	36
Estimated Fair Value	$ 1,499	$ 1,489

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27161-111563

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 45
-Paragraph 1
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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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