Loans (Aging Of Recorded Investment In Past Due Loans) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2019		Sep. 30, 2018	Sep. 30, 2019		Sep. 30, 2018	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		$ 20,021			$ 20,021			$ 29,919
Past due nonaccrual loans and loans past due 90 days or more and accruing		27,185	[1]		27,185	[1]		19,602	[2]
Total loans past due		47,206			47,206			49,521
Total current		6,376,549			6,376,549			5,660,277
Recorded Investment		6,423,755			6,423,755			5,709,798
Loans past due 90 days or more and accruing		3,348			3,348			2,302
Impaired Financing Receivable, Recorded Investment, Nonaccrual loans which are current in regards to contractual P&I payments		65,700			65,700			50,700
Financing Receivable, Modifications, Recorded Investment, During Period		7,866		$ 3,704	16,229		$ 6,566
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		2,023	[1]		2,023	[1]		1,635	[2]
Total loans past due		2,023			2,023			1,635
Total current		222,357			222,357			174,466
Recorded Investment		224,380			224,380			176,101
Loans past due 90 days or more and accruing		235			235			0
Financing Receivable, Modifications, Recorded Investment, During Period		82			82		0
Commercial Financial And Agricultural [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		2,570			2,570			4,786
Past due nonaccrual loans and loans past due 90 days or more and accruing		10,602	[1]		10,602	[1]		1,375	[2]
Total loans past due		13,172			13,172			6,161
Total current		1,132,370			1,132,370			1,071,228
Loans past due 90 days or more and accruing		0			0			10
Financing Receivable, Modifications, Recorded Investment, During Period		5,754		574	9,296		800
Construction Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		118			118			133
Past due nonaccrual loans and loans past due 90 days or more and accruing	[2]							20
Total loans past due		118			118			153
Total current		93,099			93,099			70,539
Recorded Investment		93,217			93,217			70,692
Loans past due 90 days or more and accruing		0			0			20
Financing Receivable, Modifications, Recorded Investment, During Period					0		0
Construction Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days								28
Past due nonaccrual loans and loans past due 90 days or more and accruing		12	[1]		12	[1]		19	[2]
Total loans past due		12			12			47
Total current		1,574			1,574			2,393
Recorded Investment		1,586			1,586			2,440
Loans past due 90 days or more and accruing		12			12			0
Financing Receivable, Modifications, Recorded Investment, During Period					0		12
Residential Real Estate Commercial [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		40			40			683
Past due nonaccrual loans and loans past due 90 days or more and accruing		791	[1]		791	[1]		1,104	[2]
Total loans past due		831			831			1,787
Total current		466,024			466,024			429,093
Recorded Investment		466,855			466,855			430,880
Loans past due 90 days or more and accruing		0			0
Financing Receivable, Modifications, Recorded Investment, During Period		13		304	49		304
Residential Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		10,196			10,196			13,210
Past due nonaccrual loans and loans past due 90 days or more and accruing		9,508	[1]		9,508	[1]		8,553	[2]
Total loans past due		19,704			19,704			21,763
Total current		1,156,246			1,156,246			1,113,742
Recorded Investment		1,175,950			1,175,950			1,135,505
Loans past due 90 days or more and accruing		1,641			1,641			1,124
Financing Receivable, Modifications, Recorded Investment, During Period		501		246	1,013		1,062
Residential Real Estate - HELOC [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		570			570			620
Past due nonaccrual loans and loans past due 90 days or more and accruing		845	[1]		845	[1]		907	[2]
Total loans past due		1,415			1,415			1,527
Total current		230,777			230,777			214,915
Recorded Investment		232,192			232,192			216,442
Loans past due 90 days or more and accruing		56			56			9
Financing Receivable, Modifications, Recorded Investment, During Period		138		469	364		860
Residential Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		45			45			155
Past due nonaccrual loans and loans past due 90 days or more and accruing		269	[1]		269	[1]		274	[2]
Total loans past due		314			314			429
Total current		12,747			12,747			13,934
Recorded Investment		13,061			13,061			14,363
Loans past due 90 days or more and accruing		0			0			24
Financing Receivable, Modifications, Recorded Investment, During Period		421		336	1,003		453
Commercial Financial And Agricultural [Member]
Financing Receivable, Past Due [Line Items]
Recorded Investment	[3]	1,145,542			1,145,542			1,077,389
Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		673			673			780
Past due nonaccrual loans and loans past due 90 days or more and accruing		1,354	[1]		1,354	[1]		3,584	[2]
Total loans past due		2,027			2,027			4,364
Total current		1,603,437			1,603,437			1,283,431
Recorded Investment	[3]	1,605,464			1,605,464			1,287,795
Loans past due 90 days or more and accruing		625			625
Financing Receivable, Modifications, Recorded Investment, During Period		241		1,154	3,236		1,859
Consumer [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		5,758			5,758			9,524
Past due nonaccrual loans and loans past due 90 days or more and accruing		1,572	[1]		1,572	[1]		2,131	[2]
Total loans past due		7,330			7,330			11,655
Total current		1,427,016			1,427,016			1,284,237
Recorded Investment		1,434,346			1,434,346			1,295,892
Loans past due 90 days or more and accruing		570			570			1,115
Financing Receivable, Modifications, Recorded Investment, During Period		716		621	1,186		1,216
Finance Leases Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Accruing loans past due 30-89 days		51			51			0
Past due nonaccrual loans and loans past due 90 days or more and accruing		209	[1]		209	[1]		0	[2]
Total loans past due		260			260			0
Total current		30,902			30,902			2,299
Recorded Investment		31,162			31,162			2,299
Loans past due 90 days or more and accruing		209			209			$ 0
Accruing Financing Receivable Modifications [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		1,745		897	4,943		2,043
Accruing Financing Receivable Modifications [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		82			82		0
Accruing Financing Receivable Modifications [Member] | Commercial Financial And Agricultural [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		752		22	3,237		208
Accruing Financing Receivable Modifications [Member] | Construction Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		0		0	0		0
Accruing Financing Receivable Modifications [Member] | Construction Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		0		0	0		12
Accruing Financing Receivable Modifications [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		13		55	13		55
Accruing Financing Receivable Modifications [Member] | Residential Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		286		0	340		90
Accruing Financing Receivable Modifications [Member] | Residential Real Estate - HELOC [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		31		453	121		735
Accruing Financing Receivable Modifications [Member] | Residential Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		407		336	951		437
Accruing Financing Receivable Modifications [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period					0		447
Accruing Financing Receivable Modifications [Member] | Consumer [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		174		31	199		59
Nonaccruing Financing Receivable Modifications [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		6,121		2,807	11,286		4,523
Nonaccruing Financing Receivable Modifications [Member] | Construction Real Estate Commercial [Domain]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period					0		0
Nonaccruing Financing Receivable Modifications [Member] | Commercial Financial And Agricultural [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		5,002		552	6,059		592
Nonaccruing Financing Receivable Modifications [Member] | Construction Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period					0		0
Nonaccruing Financing Receivable Modifications [Member] | Construction Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period					0		0
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate Commercial [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period				249	36		249
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate - Mortgage [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		215		246	673		972
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate - HELOC [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		107		16	243		125
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate - Installment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		14			52		16
Nonaccruing Financing Receivable Modifications [Member] | Commercial Real Estate [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		241		1,154	3,236		1,412
Nonaccruing Financing Receivable Modifications [Member] | Consumer [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		$ 542		$ 590	$ 987		$ 1,157

[1] 1) Includes an aggregate of $3.3 million of loans past due 90 days or more and accruing. The remaining loans were past due nonaccrual loans.(2) Includes an aggregate of $65.7 million of nonaccrual loans which were current in regards to contractual principal and interest payments

[2] 1) Includes an aggregate of $2.3 million of loans past due 90 days or more and accruing. The remaining loans were past due nonaccrual loans.(2) Includes an aggregate of $50.7 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.