Loans and Allowance for Credit Losses Allocation for credit losses on loans sold (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance, Loans Sold	$ 55,290	$ 71,670
Loan Charge-offs Prior to Sale, Loans Sold	(13,460)	(21,210)
Recorded Investment, Loans Sold	(41,830)	(50,460)
Proceeds From Sale Of Loans Receivable, Net of Selling Expenses	23,860	25,910
Charge-offs Upon Sale, Loan Sold	(17,970)	(24,550)
Allowance for Loan and Lease Losses, Loans Sold	(13,720)	(27,610)
Commercial - industrial, financial, and agricultural
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance, Loans Sold	23,600	19,990
Loan Charge-offs Prior to Sale, Loans Sold	(3,890)	(6,130)
Recorded Investment, Loans Sold	19,710	13,860
Proceeds From Sale Of Loans Receivable, Net of Selling Expenses	10,050	6,020
Charge-offs Upon Sale, Loan Sold	(9,660)	(7,840)
Allowance for Loan and Lease Losses, Loans Sold	(5,780)	(8,910)
Commercial Real Estate Construction Financing Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance, Loans Sold	9,930	7,720
Loan Charge-offs Prior to Sale, Loans Sold	(4,680)	(4,300)
Recorded Investment, Loans Sold	5,250	3,420
Proceeds From Sale Of Loans Receivable, Net of Selling Expenses	3,400	2,270
Charge-offs Upon Sale, Loan Sold	(1,850)	(1,150)
Allowance for Loan and Lease Losses, Loans Sold	(1,320)	(1,920)
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance, Loans Sold	21,760	43,960
Loan Charge-offs Prior to Sale, Loans Sold	(4,890)	(10,780)
Recorded Investment, Loans Sold	16,870	33,180
Proceeds From Sale Of Loans Receivable, Net of Selling Expenses	10,410	17,620
Charge-offs Upon Sale, Loan Sold	(6,460)	(15,560)
Allowance for Loan and Lease Losses, Loans Sold	$ (6,620)	$ (16,780)