Loans (Impaired Loans, Average Recorded Investment and Interest Income Recognized) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	$ 75,948	$ 75,342	$ 81,445	$ 121,482
With no related allowance recorded, interest income recognized	812	0	2,188	2
With an allowance recorded, average recorded investment	15,301	88,861	15,790	125,182
With an allowance recorded, interest income recognized	84	0	378	1
Impaired Financing Receivable, Average Recorded Investment	91,249	164,203	97,235	246,664
Impaired Financing Receivable, Interest Income, Cash Basis Method	896	0	2,566	3
Commercial and agricultural [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	1,557	2,417	1,879	3,305
With no related allowance recorded, interest income recognized	56	0	152	0
With an allowance recorded, average recorded investment	1,274	2,751	1,266	5,803
With an allowance recorded, interest income recognized	6	0	36	0
Impaired Financing Receivable, Average Recorded Investment	2,831	5,168	3,145	9,108
Impaired Financing Receivable, Interest Income, Cash Basis Method	62	0	188	0
Real estate - construction [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	15,484	29,789	18,140	49,617
With no related allowance recorded, interest income recognized	104	0	350	0
With an allowance recorded, average recorded investment	2,802	47,884	2,873	60,131
With an allowance recorded, interest income recognized	9	0	32	0
Impaired Financing Receivable, Average Recorded Investment	18,286	77,673	21,013	109,748
Impaired Financing Receivable, Interest Income, Cash Basis Method	113	0	382	0
Real estate - mortgage, 1-4 family residential [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	14,265	13,585	15,096	18,628
With no related allowance recorded, interest income recognized	81	0	292	1
With an allowance recorded, average recorded investment	6,436	16,268	6,869	16,027
With an allowance recorded, interest income recognized	41	0	163	0
Impaired Financing Receivable, Average Recorded Investment	20,701	29,853	21,965	34,655
Impaired Financing Receivable, Interest Income, Cash Basis Method	122	0	455	1
Real estate - mortgage, commercial [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	44,480	29,453	46,051	49,736
With no related allowance recorded, interest income recognized	567	0	1,388	1
With an allowance recorded, average recorded investment	4,689	21,647	4,687	42,990
With an allowance recorded, interest income recognized	27	0	145	1
Impaired Financing Receivable, Average Recorded Investment	49,169	51,100	50,738	92,726
Impaired Financing Receivable, Interest Income, Cash Basis Method	594	0	1,533	2
Consumer [Member]
Financing Receivable, Impaired [Line Items]
With no related alowance recorded, average recorded investment	162	98	279	196
With no related allowance recorded, interest income recognized	4	0	6	0
With an allowance recorded, average recorded investment	100	311	95	231
With an allowance recorded, interest income recognized	1	0	2	0
Impaired Financing Receivable, Average Recorded Investment	262	409	374	427
Impaired Financing Receivable, Interest Income, Cash Basis Method	$ 5	$ 0	$ 8	$ 0