Loans (Aging Of Recorded Investment In Past Due Loans) (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2017 USD ($) contracts		Mar. 31, 2016 USD ($) contracts	Dec. 31, 2016 USD ($)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		83		84
Accruing loans past due 30-89 days		$ 17,185			$ 26,591
Past due nonaccrual loans and loans past due 90 days or more and accruing		19,395	[1]		24,050	[2]
Total loans past due		36,580			50,641
Total current		5,291,510			5,236,189
Recorded Investment		5,328,090			5,286,830
Loans past due 90 days or more and accruing		1,886			2,138
Impaired Financing Receivable, Recorded Investment, Nonaccrual loans which are current in regards to contractual P&I payments		66,800			65,900
Financing Receivable, Modifications, Recorded Investment, During Period		$ 8,085		$ 2,529
Construction Real Estate Commercial [Domain]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		0		0
Past due nonaccrual loans and loans past due 90 days or more and accruing		$ 24	[1]		541	[2]
Total loans past due		24			541
Total current		112,329			135,200
Recorded Investment		112,353			135,741
Loans past due 90 days or more and accruing		$ 0			0
Commercial Financial And Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		6		7
Accruing loans past due 30-89 days		$ 541			371
Past due nonaccrual loans and loans past due 90 days or more and accruing		2,272	[1]		4,113	[2]
Total loans past due		2,813			4,484
Total current		996,462			993,693
Loans past due 90 days or more and accruing		10			15
Financing Receivable, Modifications, Recorded Investment, During Period		$ 4,098		$ 847
Construction Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		0		0
Accruing loans past due 30-89 days					559
Total loans past due					559
Total current		$ 48,303			48,246
Recorded Investment		48,303			48,805
Loans past due 90 days or more and accruing		$ 0			0
Construction Real Estate - Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		0		0
Accruing loans past due 30-89 days		$ 210			223
Past due nonaccrual loans and loans past due 90 days or more and accruing		49	[1]		64	[2]
Total loans past due		259			287
Total current		4,781			4,633
Recorded Investment		5,040			4,920
Loans past due 90 days or more and accruing		$ 0			12
Residential Real Estate - Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		3		2
Accruing loans past due 30-89 days		$ 170			330
Past due nonaccrual loans and loans past due 90 days or more and accruing		2,067	[1]		3,631	[2]
Total loans past due		2,237			3,961
Total current		395,350			403,666
Recorded Investment		397,587			407,627
Loans past due 90 days or more and accruing		0
Financing Receivable, Modifications, Recorded Investment, During Period		$ 2,140		$ 617
Residential Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		9		5
Accruing loans past due 30-89 days		$ 7,566			10,854
Past due nonaccrual loans and loans past due 90 days or more and accruing		9,391	[1]		9,769	[2]
Total loans past due		16,957			20,623
Total current		1,140,832			1,150,331
Recorded Investment		1,157,789			1,170,954
Loans past due 90 days or more and accruing		804			887
Financing Receivable, Modifications, Recorded Investment, During Period		$ 608		$ 316
Residential Real Estate - HELOC [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		3		6
Accruing loans past due 30-89 days		$ 632			970
Past due nonaccrual loans and loans past due 90 days or more and accruing		1,017	[1]		1,020	[2]
Total loans past due		1,649			1,990
Total current		210,482			211,304
Recorded Investment		212,131			213,294
Loans past due 90 days or more and accruing		26			25
Financing Receivable, Modifications, Recorded Investment, During Period		206		$ 186
Residential Real Estate - Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing loans past due 30-89 days		197			350
Past due nonaccrual loans and loans past due 90 days or more and accruing		178	[1]		319	[2]
Total loans past due		375			669
Total current		18,412			19,272
Recorded Investment		18,787			19,941
Loans past due 90 days or more and accruing		0			60
Financing Receivable, Modifications, Recorded Investment, During Period		34
Commercial Financial And Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Recorded Investment	[3]	$ 999,275			998,177
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		4		0
Accruing loans past due 30-89 days		$ 135			355
Past due nonaccrual loans and loans past due 90 days or more and accruing		2,591	[1]		2,499	[2]
Total loans past due		2,726			2,854
Total current		1,188,539			1,157,010
Recorded Investment	[3]	1,191,265			1,159,864
Loans past due 90 days or more and accruing		0
Financing Receivable, Modifications, Recorded Investment, During Period		$ 379
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		57		64
Accruing loans past due 30-89 days		$ 7,734			12,579
Past due nonaccrual loans and loans past due 90 days or more and accruing		1,806	[1]		2,094	[2]
Total loans past due		9,540			14,673
Total current		1,172,314			1,109,562
Recorded Investment		1,181,854			1,124,235
Loans past due 90 days or more and accruing		1,046			1,139
Financing Receivable, Modifications, Recorded Investment, During Period		620		$ 563
Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Accruing loans past due 30-89 days		0			0
Past due nonaccrual loans and loans past due 90 days or more and accruing		0	[1]		0	[2]
Total loans past due		0			0
Total current		3,706			3,272
Recorded Investment		$ 3,706			$ 3,272
Residential Real Estate - Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Number of Contracts, During Period | contracts		1		0
Accruing Financing Receivable Modifications [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		$ 3,585		$ 346
Accruing Financing Receivable Modifications [Member] | Commercial Financial And Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		3,079		131
Accruing Financing Receivable Modifications [Member] | Construction Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		0		0
Accruing Financing Receivable Modifications [Member] | Construction Real Estate - Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		0		0
Accruing Financing Receivable Modifications [Member] | Residential Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		0		99
Accruing Financing Receivable Modifications [Member] | Residential Real Estate - HELOC [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		200		64
Accruing Financing Receivable Modifications [Member] | Residential Real Estate - Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		34
Accruing Financing Receivable Modifications [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		272		52
Nonaccruing Financing Receivable Modifications [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		4,500		2,183
Nonaccruing Financing Receivable Modifications [Member] | Commercial Financial And Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		1,019		716
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate - Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		2,140		617
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		608		217
Nonaccruing Financing Receivable Modifications [Member] | Residential Real Estate - HELOC [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		6		122
Nonaccruing Financing Receivable Modifications [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		379
Nonaccruing Financing Receivable Modifications [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing Receivable, Modifications, Recorded Investment, During Period		$ 348		$ 511

[1] 1) Includes $1.9 million of loans past due 90 days or more and accruing. The remaining are past due nonaccrual loans.(2) Includes $66.8 million of nonaccrual loans which are current in regards to contractual principal and interest payments

[2] 1) Includes $2.1 million of loans past due 90 days or more and accruing. The remaining are past due nonaccrual loans.(2) Includes $65.9 million of nonaccrual loans which are 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.