Allowance For Loan Losses (Composition Of The Allowance For Loan Losses) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012		Dec. 31, 2011		Mar. 31, 2011	Dec. 31, 2010
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	$ 59,758		$ 68,444		$ 148,530	$ 143,575
Loan balance	4,324,383		4,317,099
Allowance for loan losses as a percentage of loan balance	1.38%		1.59%
Recorded investment	4,338,583		4,331,783
Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	9,505		15,935
Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	50,253		52,509
Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	179,293		187,135
Allowance for loan losses as a percentage of loan balance	5.30%		8.52%
Recorded investment	179,424		187,135
Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	4,145,090		4,129,964
Allowance for loan losses as a percentage of loan balance	1.21%		1.27%
Recorded investment	4,159,159		4,144,648
Commercial, Financial And Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	18,328		16,950		11,791	11,555
Loan balance	752,392		743,797
Allowance for loan losses as a percentage of loan balance	2.44%		2.28%
Recorded investment	755,831		746,918
Commercial, Financial And Agricultural [Member] | Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	4,704		5,819
Commercial, Financial And Agricultural [Member] | Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	13,624		11,131
Commercial, Financial And Agricultural [Member] | Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	40,210		40,621
Allowance for loan losses as a percentage of loan balance	11.70%		14.33%
Recorded investment	40,241		40,621
Commercial, Financial And Agricultural [Member] | Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	712,182		703,176
Allowance for loan losses as a percentage of loan balance	1.91%		1.58%
Recorded investment	715,590		706,297
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	12,006		15,539		25,220	24,369
Loan balance	1,088,348	[1]	1,108,574	[1]
Allowance for loan losses as a percentage of loan balance	1.10%		1.40%
Recorded investment	1,092,143	[1]	1,112,809	[1]
Commercial Real Estate [Member] | Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	1,506		4,431
Commercial Real Estate [Member] | Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	10,500		11,108
Commercial Real Estate [Member] | Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	43,265		51,978
Allowance for loan losses as a percentage of loan balance	3.48%		8.52%
Recorded investment	43,305		51,978
Commercial Real Estate [Member] | Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	1,045,083		1,056,596
Allowance for loan losses as a percentage of loan balance	1.00%		1.05%
Recorded investment	1,048,838		1,060,831
Construction Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	9,747		14,433		71,835	70,462
Loan balance	203,815		217,546
Allowance for loan losses as a percentage of loan balance	4.78%		6.63%
Recorded investment	204,388		218,096
Construction Real Estate [Member] | Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	2,096		3,414
Construction Real Estate [Member] | Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	7,651		11,019
Construction Real Estate [Member] | Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	52,046		50,240
Allowance for loan losses as a percentage of loan balance	4.03%		6.80%
Recorded investment	52,106		50,240
Construction Real Estate [Member] | Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	151,769		167,306
Allowance for loan losses as a percentage of loan balance	5.04%		6.59%
Recorded investment	152,282		167,856
Residential Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	13,868		15,692		32,415	30,259
Loan balance	1,667,699		1,628,618
Allowance for loan losses as a percentage of loan balance	0.83%		0.96%
Recorded investment	1,671,460		1,632,423
Residential Real Estate [Member] | Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	1,199		2,271
Residential Real Estate [Member] | Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	12,669		13,421
Residential Real Estate [Member] | Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	43,752		44,276
Allowance for loan losses as a percentage of loan balance	2.74%		5.13%
Recorded investment	43,752		44,276
Residential Real Estate [Member] | Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	1,623,947		1,584,342
Allowance for loan losses as a percentage of loan balance	0.78%		0.85%
Recorded investment	1,627,708		1,588,147
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	5,809		5,830		7,265	6,925
Loan balance	610,180		616,505
Allowance for loan losses as a percentage of loan balance	0.95%		0.95%
Recorded investment	612,760		619,435
Consumer [Member] | Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans	5,809		5,830
Consumer [Member] | Loans Individually Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	20		20
Recorded investment	20		20
Consumer [Member] | Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	610,160		616,485
Allowance for loan losses as a percentage of loan balance	0.95%		0.95%
Recorded investment	612,740		619,415
Leases [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Ending allowance balance attributed to loans					4	5
Loan balance	1,949		2,059
Recorded investment	2,001		2,102
Leases [Member] | Loans Collectively Evaluated For Impairment [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loan balance	1,949		2,059
Recorded investment	$ 2,001		$ 2,102

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