Allowance For Loan Losses (Activity In The Allowance For Loan Losses) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan and Lease Losses, Reserve Estimate Methodology, Historical Loss Period Factor			108 months	96 months
Financing Receivable, Allowance for Credit Losses, Write-downs	$ 2,987	$ 3,450
Financing Receivable, Allowance for Credit Losses, Recovery	2,345	2,171
Financing Receivables Allowance For Credit Losses Net Charge Offs	642	1,279
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	51,512	49,988	$ 49,988
Ending balance	53,368	48,969	51,512	$ 49,988
Provision for Loan, Lease, and Other Losses	2,498	260
Commercial Financial And Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	198	649
Financing Receivable, Allowance for Credit Losses, Recovery	416	652
Financing Receivables Allowance For Credit Losses Net Charge Offs	(218)	(3)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	16,777	15,022	15,022
Ending balance	17,337	14,077	16,777	15,022
Provision for Loan, Lease, and Other Losses	342	(948)
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	54	47
Financing Receivable, Allowance for Credit Losses, Recovery	59	87
Financing Receivables Allowance For Credit Losses Net Charge Offs	(5)	(40)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	9,768	9,601	9,601
Ending balance	10,193	9,488	9,768	9,601
Provision for Loan, Lease, and Other Losses	420	(153)
Construction Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	0	0
Financing Receivable, Allowance for Credit Losses, Recovery	88	59
Financing Receivables Allowance For Credit Losses Net Charge Offs	(88)	(59)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	4,463	4,430	4,430
Ending balance	4,564	4,463	4,463	4,430
Provision for Loan, Lease, and Other Losses	13	(26)
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	29	116
Financing Receivable, Allowance for Credit Losses, Recovery	382	360
Financing Receivables Allowance For Credit Losses Net Charge Offs	(353)	(244)
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	8,731	9,321	9,321
Ending balance	9,170	9,415	8,731	9,321
Provision for Loan, Lease, and Other Losses	86	(150)
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	2,706	2,638
Financing Receivable, Allowance for Credit Losses, Recovery	1,400	1,013
Financing Receivables Allowance For Credit Losses Net Charge Offs	1,306	1,625
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	11,773	11,614	11,614
Ending balance	12,104	11,526	11,773	11,614
Provision for Loan, Lease, and Other Losses	1,637	1,537
Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Financing Receivable, Allowance for Credit Losses, Write-downs	0	0
Financing Receivable, Allowance for Credit Losses, Recovery	0	0
Financing Receivables Allowance For Credit Losses Net Charge Offs	0	0
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0	0
Ending balance	0	0	$ 0	$ 0
Provision for Loan, Lease, and Other Losses	$ 0	$ 0