Loans and Allowance for Credit Losses Allocation for Credit Losses on Loans Sold (Details) (USD $) In Thousands, unless otherwise specified	1 Months Ended	3 Months Ended	9 Months Ended
	Jun. 30, 2012	Sep. 30, 2013	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance of loans sold	$ 60,000	$ 18,280	$ 55,290
Charge-offs prior to sale	(15,890)	(1,860)	(13,460)
Net recorded investment in loans sold	44,110	16,420	41,830
Proceeds from sale, net of selling expenses	22,930	10,380	23,860
Total charge-off upon sale	21,180	6,040	17,970
Existing allocation for credit losses on sold loans	(24,120)	(770)	(13,720)
Commercial - industrial, financial, and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance of loans sold	15,270	11,950	23,600
Charge-offs prior to sale	(3,750)	(1,860)	(3,890)
Net recorded investment in loans sold	11,520	10,090	19,710
Proceeds from sale, net of selling expenses	5,170	6,020	10,050
Total charge-off upon sale	6,350	4,070	9,660
Existing allocation for credit losses on sold loans	(7,510)	(450)	(5,780)
Real-estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance of loans sold	6,280	1,490	9,930
Charge-offs prior to sale	(3,540)	0	(4,680)
Net recorded investment in loans sold	2,740	1,490	5,250
Proceeds from sale, net of selling expenses	1,850	1,050	3,400
Total charge-off upon sale	890	440	1,850
Existing allocation for credit losses on sold loans	(1,520)	0	(1,320)
Real-estate commercial mortage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balance of loans sold	38,450	4,840	21,760
Charge-offs prior to sale	(8,600)	0	(4,890)
Net recorded investment in loans sold	29,850	4,840	16,870
Proceeds from sale, net of selling expenses	15,910	3,310	10,410
Total charge-off upon sale	13,940	1,530	6,460
Existing allocation for credit losses on sold loans	$ (15,090)	$ (320)	$ (6,620)