Loans and Allowance for Credit Losses Modified Under Troubled Debt Restructurings (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011		Dec. 31, 2010
Financing Receivable, Modifications [Line Items]
Total accruing troubled debt restructurings	$ 66,175		$ 67,809
Non-accrual troubled debt restructurings	32,587	[1]	51,175	[1]
Total troubled debt restructurings	98,762		118,984
Financing Receivable, Modifications, Number of Contracts	53
Financing Receivable, Modifications, Recorded Investment	35,006
Real-estate - residential mortgage
Financing Receivable, Modifications [Line Items]
Total accruing troubled debt restructurings	32,331		37,826
Financing Receivable, Modifications, Number of Contracts	17
Financing Receivable, Modifications, Recorded Investment	3,912
Real-estate commercial mortage
Financing Receivable, Modifications [Line Items]
Total accruing troubled debt restructurings	22,425		18,778
Financing Receivable, Modifications, Number of Contracts	20
Financing Receivable, Modifications, Recorded Investment	18,821
Real-estate - construction
Financing Receivable, Modifications [Line Items]
Total accruing troubled debt restructurings	7,645		5,440
Commercial - industrial, financial, and agricultural
Financing Receivable, Modifications [Line Items]
Total accruing troubled debt restructurings	3,581		5,502
Construction - Commercial Residential [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	4
Financing Receivable, Modifications, Recorded Investment	8,991
Consumer and Home Equity [Member]
Financing Receivable, Modifications [Line Items]
Total accruing troubled debt restructurings	193		263
Commercial - Secured [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	11
Financing Receivable, Modifications, Recorded Investment	3,150
Commercial - Unsecured [Member]
Financing Receivable, Modifications [Line Items]
Financing Receivable, Modifications, Number of Contracts	1
Financing Receivable, Modifications, Recorded Investment	$ 132

[1] 1)Included within non-accrual loans in the preceding table