Allowance For Loan Losses (Activity In The Allowance For Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan and Lease Losses, Reserve Estimate Methodology, Historical Loss Period Factor					96 months	84 months
Financing Receivable, Allowance for Credit Losses, Write-downs	$ 2,716	$ 3,046	$ 6,166	$ 6,754
Financing Receivable, Allowance for Credit Losses, Recovery	1,813	2,365	3,984	4,495
Financing Receivables Allowance For Credit Losses Net Charge Offs	903	681	2,182	2,259
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	48,969	49,922	49,988	50,624	$ 50,624
Ending balance	49,452	53,822	49,452	53,822	49,988	$ 50,624
Provision for Loan, Lease, and Other Losses	1,386	4,581	1,646	5,457
Commercial Financial And Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	287	318	936	657
Financing Receivable, Allowance for Credit Losses, Recovery	206	163	858	532
Financing Receivables Allowance For Credit Losses Net Charge Offs	81	155	78	125
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	14,077	13,437	15,022	13,434	13,434
Ending balance	14,478	16,746	14,478	16,746	15,022	13,434
Provision for Loan, Lease, and Other Losses	482	3,464	(466)	3,437
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	182	310	229	422
Financing Receivable, Allowance for Credit Losses, Recovery	89	241	176	355
Financing Receivables Allowance For Credit Losses Net Charge Offs	93	69	53	67
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	9,488	10,281	9,601	10,432	10,432
Ending balance	9,406	10,451	9,406	10,451	9,601	10,432
Provision for Loan, Lease, and Other Losses	11	239	(142)	86
Construction Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	31	0	31	27
Financing Receivable, Allowance for Credit Losses, Recovery	220	325	279	383
Financing Receivables Allowance For Credit Losses Net Charge Offs	(189)	(325)	(248)	(356)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,463	4,368	4,430	5,247	5,247
Ending balance	4,652	4,677	4,652	4,677	4,430	5,247
Provision for Loan, Lease, and Other Losses	0	(16)	(26)	(926)
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	102	290	218	770
Financing Receivable, Allowance for Credit Losses, Recovery	244	336	604	627
Financing Receivables Allowance For Credit Losses Net Charge Offs	(142)	(46)	(386)	143
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	9,415	10,745	9,321	10,958	10,958
Ending balance	9,245	10,319	9,245	10,319	9,321	10,958
Provision for Loan, Lease, and Other Losses	(312)	(472)	(462)	(496)
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	2,114	2,128	4,752	4,878
Financing Receivable, Allowance for Credit Losses, Recovery	1,054	1,300	2,067	2,598
Financing Receivables Allowance For Credit Losses Net Charge Offs	1,060	828	2,685	2,280
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,526	11,091	11,614	10,553	10,553
Ending balance	11,671	11,629	11,671	11,629	11,614	10,553
Provision for Loan, Lease, and Other Losses	1,205	1,366	2,742	3,356
Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	0	0	0	0
Financing Receivable, Allowance for Credit Losses, Recovery	0	0	0	0
Financing Receivables Allowance For Credit Losses Net Charge Offs	0	0	0	0
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0	0	0	0
Ending balance	0	0	0	0	$ 0	$ 0
Provision for Loan, Lease, and Other Losses	$ 0	$ 0	$ 0	$ 0