Investments (Aggregate Carrying And Approximate Market Values Of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 586,690	$ 551,103
Gross Unrealized Gains	526	7,211
Gross Unrealized Losses	24,213	7,925
Estimated Fair Value	563,003	550,389
U.S Treasuries and U.S. Government Agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1	2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	1	2
Obligations Of States And Political Subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	92,972	94,552
Gross Unrealized Gains	265	2,051
Gross Unrealized Losses	1,673	407
Estimated Fair Value	91,564	96,196
U.S. Government Agencies Mortgage-backed Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	469,810	425,559
Gross Unrealized Gains	222	1,093
Gross Unrealized Losses	22,286	7,305
Estimated Fair Value	447,746	419,347
Private Label
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	523	649
Gross Unrealized Gains	6	3
Gross Unrealized Losses	0	0
Estimated Fair Value	529	652
Trust Preferred Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,772	4,764
Gross Unrealized Gains	26	26
Gross Unrealized Losses	0	54
Estimated Fair Value	4,798	4,736
Corporate Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,086	21,916
Gross Unrealized Gains	7	475
Gross Unrealized Losses	172	123
Estimated Fair Value	16,921	22,268
Debt Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	585,164	547,442
Gross Unrealized Gains	526	3,648
Gross Unrealized Losses	24,131	7,889
Estimated Fair Value	561,559	543,201
Equity Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		2,136
Gross Unrealized Gains		3,563
Gross Unrealized Losses		0
Estimated Fair Value		5,699
Money Market Funds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	1,526	1,525
Gross Unrealized Gains	0	0
Gross Unrealized Losses	82	36
Estimated Fair Value	$ 1,444	$ 1,489

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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

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