Investment Securities (Amortized Cost And Fair Value Of Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Investment [Line Items]
Securities available for sale, Amortized Cost	$ 522,147	$ 528,458
Securities available for sale, Unrealized Gains	1,217	1,681
Securities available for sale, Unrealized Losses	13,167	5,166
Securities available for sale	510,197	524,973
Securities held to maturity, Amortized Cost	501,905	516,466
Securities held to maturity, Unrealized Gains	1,303	2,341
Securities held to maturity, Unrealized Losses	9,707	5,824
Securities held to maturity, fair value	493,501	512,983
U.S. Government Agencies And Government Sponsored Enterprises [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	162,610	163,025
Securities available for sale, Unrealized Gains	18	122
Securities available for sale, Unrealized Losses	3,812	1,258
Securities available for sale	158,816	161,889
State And Political Subdivisions [Member]
Investment [Line Items]
Securities held to maturity, Amortized Cost	279,085	283,557
Securities held to maturity, Unrealized Gains	1,303	2,317
Securities held to maturity, Unrealized Losses	1,721	662
Securities held to maturity, fair value	278,667	285,212
Collateralized Mortgage Obligations [Member] \| Federal National Mortgage Association [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	186	217
Securities available for sale, Unrealized Gains		1
Securities available for sale, Unrealized Losses		1
Securities available for sale	186	217
Securities held to maturity, Amortized Cost	72,584	76,432
Securities held to maturity, Unrealized Losses	2,649	1,958
Securities held to maturity, fair value	69,935	74,474
Collateralized Mortgage Obligations [Member] \| Federal Home Loan Mortgage Corporation [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	43	45
Securities available for sale	43	45
Securities held to maturity, Amortized Cost	89,871	93,810
Securities held to maturity, Unrealized Gains		3
Securities held to maturity, Unrealized Losses	3,297	2,165
Securities held to maturity, fair value	86,574	91,648
Collateralized Mortgage Obligations [Member] \| Government National Mortgage Association [Member]
Investment [Line Items]
Securities held to maturity, Amortized Cost	21,398	22,881
Securities held to maturity, Unrealized Gains		5
Securities held to maturity, Unrealized Losses	718	502
Securities held to maturity, fair value	20,680	22,384
Collateralized Mortgage Obligations [Member] \| Privately Issued [Member]
Investment [Line Items]
Securities available for sale, Unrealized Gains	951	976
Securities available for sale	951	976
Mortgage-Backed Securities [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	359,537	365,433
Securities available for sale, Unrealized Gains	1,199	1,559
Securities available for sale, Unrealized Losses	9,355	3,908
Securities available for sale	351,381	363,084
Securities held to maturity, Amortized Cost	222,820	232,909
Securities held to maturity, Unrealized Gains		24
Securities held to maturity, Unrealized Losses	7,986	5,162
Securities held to maturity, fair value	214,834	227,771
Mortgage-Backed Securities [Member] \| Federal National Mortgage Association [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	307,972	311,830
Securities available for sale, Unrealized Gains	83	313
Securities available for sale, Unrealized Losses	7,922	3,220
Securities available for sale	300,133	308,923
Securities held to maturity, Amortized Cost	9,503	9,732
Securities held to maturity, Unrealized Gains		16
Securities held to maturity, Unrealized Losses	289	88
Securities held to maturity, fair value	9,214	9,660
Mortgage-Backed Securities [Member] \| Federal Home Loan Mortgage Corporation [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	40,078	41,290
Securities available for sale, Unrealized Gains	34	76
Securities available for sale, Unrealized Losses	1,361	675
Securities available for sale	38,751	40,691
Securities held to maturity, Amortized Cost	3,193	3,213
Securities held to maturity, Unrealized Losses	193	119
Securities held to maturity, fair value	3,000	3,094
Mortgage-Backed Securities [Member] \| Government National Mortgage Association [Member]
Investment [Line Items]
Securities available for sale, Amortized Cost	11,258	12,051
Securities available for sale, Unrealized Gains	131	193
Securities available for sale, Unrealized Losses	72	12
Securities available for sale	11,317	12,232
Securities held to maturity, Amortized Cost	26,271	26,841
Securities held to maturity, Unrealized Losses	840	330
Securities held to maturity, fair value	$ 25,431	$ 26,511

Line items represent reporting concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 12
-Sentence Column A

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

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

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

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount after other than temporary impairment (OTTI) accretion, of investments in debt securities classified as held-to-maturity.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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