Securities (Summary Of Amortized Cost, Unrealized Gains, Unrealized Losses And Estimated Fair Values) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	$ 294,251	$ 324,771
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,907	5,329
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	3,011	1,514
Debt Securities, Available-for-sale	293,147	328,586
U.S. Government and agencies and corporations [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	26,303	31,260
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	203	498
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	366	145
Debt Securities, Available-for-sale	26,140	31,613
Government-sponsored agencies [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	80,883	120,948
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	603	1,276
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1,177	903
Debt Securities, Available-for-sale	80,309	121,321
Nongovernment-sponsored entities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	611	2,045
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	4	39
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	1	7
Debt Securities, Available-for-sale	614	2,077
State and Political Subdivisions General Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	6,081	6,090
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	0	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	126	55
Debt Securities, Available-for-sale	5,955	6,035
State and policital subdivisions, Other revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	13,457	11,657
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	17	47
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	186	62
Debt Securities, Available-for-sale	13,288	11,642
Corporate debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	14,807	16,375
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	9	0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	304	130
Debt Securities, Available-for-sale	14,512	16,245
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	25,288
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	10
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	123
Debt Securities, Available-for-sale	25,175
Total taxable debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	167,430	188,375
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	846	1,860
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	2,283	1,302
Debt Securities, Available-for-sale	165,993	188,933
Tax Exempt State and Political Subdivisions General Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	65,626	65,560
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	624	1,530
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	344	198
Debt Securities, Available-for-sale	65,906	66,892
Tax Exempt State and Political Subdivisions Water and Sewer Revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	20,018	23,108
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	225	566
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	98	3
Debt Securities, Available-for-sale	20,145	23,671
Tax Exempt State and Political Subdivisions Lease Revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	10,980	13,024
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	135	451
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	7	2
Debt Securities, Available-for-sale	11,108	13,473
Tax Exempt State and Political Subdivisions Electric Revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost		6,205
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		128
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		0
Debt Securities, Available-for-sale		6,333
Tax Exempt State and Political Subdivisions Sales Tax Revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost		4,126
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		140
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		0
Debt Securities, Available-for-sale		4,266
Tax Exempt State and Political Subdivisions University Revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost		5,272
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax		38
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax		9
Debt Securities, Available-for-sale		5,301
Tax Exempt State and Political Subdivisions Other Revenues [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	30,197	19,101
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	77	616
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	279	0
Debt Securities, Available-for-sale	29,995	19,717
Total tax-exempt debt securities [Member]
Debt Securities, Available-for-sale [Line Items]
Total Amortized Cost	126,821	136,396
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	1,061	3,469
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	728	212
Debt Securities, Available-for-sale	$ 127,154	$ 139,653