Loans (Composition Of Loan Portfolio By Class Of Loan) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	$ 118,251		$ 142,362	$ 118,251		$ 142,362	$ 137,339
Loan balance	4,573,537			4,573,537			4,450,322
Accrued interest receivable	13,758			13,758			13,587
Recorded Investment	4,587,295			4,587,295			4,463,909
Impaired Financing Receivable, Average Recorded Investment	122,707		159,750	127,756		171,347
Impaired Financing Receivable, Interest Income, Cash Basis Method	704		1,095	2,083		2,515
Commercial Financial And Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	19,871		22,103	19,871		22,103
Impaired Financing Receivable, Average Recorded Investment	20,803		35,720	21,182		38,989
Impaired Financing Receivable, Interest Income, Cash Basis Method	124		100	334		410
Construction Real Estate - SEPH Commercial Land And Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	6,489		13,261	6,489		13,261
Loan balance	7,611	[1]		7,611	[1]		15,105	[1]
Accrued interest receivable	14	[1]		14	[1]		37	[1]
Recorded Investment	7,625	[1]		7,625	[1]		15,142	[1]
Impaired Financing Receivable, Average Recorded Investment	7,579		14,991	9,722		18,481
Impaired Financing Receivable, Interest Income, Cash Basis Method	0		0	0		0
Construction Real Estate - Remaining Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	15,606		27,418	15,606		27,418
Loan balance	103,866			103,866			115,473
Accrued interest receivable	256			256			331
Recorded Investment	104,122			104,122			115,804
Impaired Financing Receivable, Average Recorded Investment	17,249		28,400	19,118		28,633
Impaired Financing Receivable, Interest Income, Cash Basis Method	136		411	548		861
Construction Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	27,516			27,516			26,373
Accrued interest receivable	77			77			81
Recorded Investment	27,593			27,593			26,454
Construction Real Estate - Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	7,424			7,424			8,577
Accrued interest receivable	25			25			33
Recorded Investment	7,449			7,449			8,610
Residential Real Estate - Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	34,477		36,583	34,477		36,583
Loan balance	401,894			401,894			392,203
Accrued interest receivable	907			907			959
Recorded Investment	402,801			402,801			393,162
Impaired Financing Receivable, Average Recorded Investment	34,860		37,121	35,531		40,199
Impaired Financing Receivable, Interest Income, Cash Basis Method	115		233	357		398
Residential Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	1,135,632			1,135,632			1,064,787
Accrued interest receivable	1,789			1,789			1,399
Recorded Investment	1,137,421			1,137,421			1,066,186
Residential Real Estate - HELOC [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	212,289			212,289			212,905
Accrued interest receivable	816			816			892
Recorded Investment	213,105			213,105			213,797
Residential Real Estate - Installment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	36,131			36,131			43,750
Accrued interest receivable	137			137			176
Recorded Investment	36,268			36,268			43,926
Commercial Financial And Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	806,864	[1]		806,864	[1]		823,927	[1]
Accrued interest receivable	3,236	[1]		3,236	[1]		2,976	[1]
Recorded Investment	810,100	[1]		810,100	[1]		826,903	[1]
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	41,009		42,978	41,009		42,978
Loan balance	1,115,226	[1]		1,115,226	[1]		1,092,164	[1]
Accrued interest receivable	3,888	[1]		3,888	[1]		3,839	[1]
Recorded Investment	1,119,114	[1]		1,119,114	[1]		1,096,003	[1]
Impaired Financing Receivable, Average Recorded Investment	41,417		43,499	41,642		45,026
Impaired Financing Receivable, Interest Income, Cash Basis Method	329		351	844		845
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Impaired Financing Receivable, Recorded Investment	799		19	799		19
Loan balance	715,763			715,763			651,930
Accrued interest receivable	2,564			2,564			2,835
Recorded Investment	718,327			718,327			654,765
Impaired Financing Receivable, Average Recorded Investment	799		19	561		19
Impaired Financing Receivable, Interest Income, Cash Basis Method	0		0	0		1
Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loan balance	3,321			3,321			3,128
Accrued interest receivable	49			49			29
Recorded Investment	$ 3,370			$ 3,370			$ 3,157

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