Investments (Aggregate Carrying And Approximate Market Values Of Available-For-Sale Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 570,653	$ 551,103
Gross Unrealized Gains	1,063	7,211
Gross Unrealized Losses	19,113	7,925
Estimated Fair Value	552,603	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	93,596	94,552
Gross Unrealized Gains	600	2,051
Gross Unrealized Losses	1,156	407
Estimated Fair Value	93,040	96,196
U.S. Government Agencies Mortgage-backed Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	453,109	425,559
Gross Unrealized Gains	407	1,093
Gross Unrealized Losses	17,732	7,305
Estimated Fair Value	435,784	419,347
Private Label
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	558	649
Gross Unrealized Gains	5	3
Gross Unrealized Losses	0	0
Estimated Fair Value	563	652
Trust Preferred Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	4,769	4,764
Gross Unrealized Gains	28	26
Gross Unrealized Losses	0	54
Estimated Fair Value	4,797	4,736
Corporate Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	17,095	21,916
Gross Unrealized Gains	23	475
Gross Unrealized Losses	155	123
Estimated Fair Value	16,963	22,268
Debt Securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	569,128	547,442
Gross Unrealized Gains	1,063	3,648
Gross Unrealized Losses	19,043	7,889
Estimated Fair Value	551,148	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	1,525	1,525
Gross Unrealized Gains	0	0
Gross Unrealized Losses	70	36
Estimated Fair Value	$ 1,455	$ 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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