Loans (Impaired Loans, Average Recorded Investment and Interest Income Recognized) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	$ 57,601	$ 64,954
With no related allowance recorded, interest income recognized	113	47
With an allowance recorded, average recorded investment	16,357	41,416
With an allowance recorded, interest income recognized	17	28
Impaired Financing Receivable, Average Recorded Investment	73,958	106,370
Impaired Financing Receivable, Interest Income, Cash Basis Method	130	75
Commercial and agricultural [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	886	3,132
With no related allowance recorded, interest income recognized	0	7
With an allowance recorded, average recorded investment	917	1,668
With an allowance recorded, interest income recognized	5	0
Impaired Financing Receivable, Average Recorded Investment	1,803	4,800
Impaired Financing Receivable, Interest Income, Cash Basis Method	5	7
Real estate - construction [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	9,233	13,414
With no related allowance recorded, interest income recognized	0	4
With an allowance recorded, average recorded investment	2,111	12,050
With an allowance recorded, interest income recognized	0	2
Impaired Financing Receivable, Average Recorded Investment	11,344	25,464
Impaired Financing Receivable, Interest Income, Cash Basis Method	0	6
Real estate - mortgage, 1-4 family residential [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	13,472	18,199
With no related allowance recorded, interest income recognized	26	6
With an allowance recorded, average recorded investment	4,666	12,965
With an allowance recorded, interest income recognized	8	18
Impaired Financing Receivable, Average Recorded Investment	18,138	31,164
Impaired Financing Receivable, Interest Income, Cash Basis Method	34	24
Real estate - mortgage, commercial [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	34,010	29,810
With no related allowance recorded, interest income recognized	87	30
With an allowance recorded, average recorded investment	8,663	14,522
With an allowance recorded, interest income recognized	4	8
Impaired Financing Receivable, Average Recorded Investment	42,673	44,332
Impaired Financing Receivable, Interest Income, Cash Basis Method	91	38
Consumer [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	0	399
With no related allowance recorded, interest income recognized	0	0
With an allowance recorded, average recorded investment	0	211
With an allowance recorded, interest income recognized	0	0
Impaired Financing Receivable, Average Recorded Investment	0	610
Impaired Financing Receivable, Interest Income, Cash Basis Method	$ 0	$ 0