Loans (Aging Of Recorded Investment In Past Due Loans) (Details) - USD ($) $ in Thousands		Jun. 30, 2020		Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		$ 12,761		$ 21,749
Past due nonaccrual loans and loans past due 90 days or more and accruing		24,570	[1]	26,535	[2]
Total loans past due		37,331		48,284
Total current		7,188,981		6,472,341
Recorded Investment		7,226,312		6,520,625
Loans past due 90 days or more and accruing		1,763		2,737
Impaired Financing Receivable, Recorded Investment, Nonaccrual loans which are current in regards to contractual P&I payments		77,600		66,300
Construction Real Estate Commercial [Domain]
Financing Receivable, Past Due [Line Items]
Past due nonaccrual loans and loans past due 90 days or more and accruing	[1]	25
Total loans past due		25
Total current		246,106		234,463
Recorded Investment		246,131		234,463
Loans past due 90 days or more and accruing		0		0
Commercial Financial And Agricultural [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		1,887		582
Past due nonaccrual loans and loans past due 90 days or more and accruing		12,239	[1]	12,407	[2]
Total loans past due		14,126		12,989
Total current		1,727,883		1,176,514
Loans past due 90 days or more and accruing		0		28
Construction Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		398		397
Total loans past due		398		397
Total current		105,352		96,405
Recorded Investment		105,750		96,802
Loans past due 90 days or more and accruing		0		0
Construction Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		14		24
Total loans past due		14		24
Total current		1,146		1,468
Recorded Investment		1,160		1,492
Loans past due 90 days or more and accruing		0		0
Residential Real Estate Commercial [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		152
Past due nonaccrual loans and loans past due 90 days or more and accruing		797	[1]	908	[2]
Total loans past due		949		908
Total current		499,059		479,512
Recorded Investment		500,008		480,420
Loans past due 90 days or more and accruing		0
Residential Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		6,390		12,841
Past due nonaccrual loans and loans past due 90 days or more and accruing		8,332	[1]	9,153	[2]
Total loans past due		14,722		21,994
Total current		1,221,246		1,155,703
Recorded Investment		1,235,968		1,177,697
Loans past due 90 days or more and accruing		784		1,209
Residential Real Estate - HELOC [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		347		652
Past due nonaccrual loans and loans past due 90 days or more and accruing		718	[1]	779	[2]
Total loans past due		1,065		1,431
Total current		204,117		224,448
Recorded Investment		205,182		225,879
Loans past due 90 days or more and accruing		14		44
Residential Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		62		164
Past due nonaccrual loans and loans past due 90 days or more and accruing		180	[1]	338	[2]
Total loans past due		242		502
Total current		10,508		12,093
Recorded Investment		10,750		12,595
Loans past due 90 days or more and accruing		0
Commercial Financial And Agricultural [Member]
Financing Receivable, Past Due [Line Items]
Recorded Investment	[3]	1,742,009		1,189,503
Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		144		160
Past due nonaccrual loans and loans past due 90 days or more and accruing		1,351	[1]	1,143	[2]
Total loans past due		1,495		1,303
Total current		1,637,960		1,613,681
Recorded Investment	[3]	1,639,455		1,614,984
Loans past due 90 days or more and accruing		645		625
Consumer [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		3,367		6,561
Past due nonaccrual loans and loans past due 90 days or more and accruing		902	[1]	1,621	[2]
Total loans past due		4,269		8,182
Total current		1,506,785		1,448,507
Recorded Investment		1,511,054		1,456,689
Loans past due 90 days or more and accruing		320		645
Finance Leases Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		0		368
Past due nonaccrual loans and loans past due 90 days or more and accruing		26	[1]	186	[2]
Total loans past due		26		554
Total current		28,819		29,547
Recorded Investment		28,845		30,101
Loans past due 90 days or more and accruing		$ 0		$ 186

[1] 1) Includes an aggregate of $1.8 million of loans past due 90 days or more and accruing. The remaining loans were past due nonaccrual loans.(2) Includes an aggregate of $77.6 million of nonaccrual loans which were current in regards to contractual principal and interest payments

[2] 1) Includes an aggregate of $2.7 million of loans past due 90 days or more and accruing. The remaining loans were past due nonaccrual loans.        (2) Includes an aggregate of $66.3 million of nonaccrual loans which were current in regards to contractual principal and interest payments.

[3] Included within each of commercial, financial and agricultural loans and commercial real estate loans is an immaterial amount of consumer loans that are not broken out by class.