Loans (Textual) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 Loans BaordOfDirectors Tenants Segment employee	Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Modified Loans Not Included as a TDR and Reported in Nonaccrual Loans	$ 47,500,000	$ 41,800,000
Number of portfolio segment	2
Number of classes of loans	7
Number of tenants under lease of real estate	1
Loans held-for-sale	17,665,000	18,818,000
Number of bank executives and senior officers with credit decision limits similar to group loan authorities	4
Number of members of the board of directors in loan committee	10
Minimum due period of loans consider in a nonperforming status	90 days
Interest income recognized on nonaccrual loans while in accruing status	1,100,000	1,000,000	1,100,000
Interest lost on nonaccrual loans	4,500,000	6,000,000	5,900,000
Interest income recognized on TDRs	2,900,000	2,300,000	1,800,000
Difference between recorded investment and unpaid principal balance of loan	21,100,000	32,100,000
Confirmed losses (partial charge-offs)	17,300,000	21,700,000
Fair value of discount adjustment	3,800,000	10,400,000
Financing receivable allowance for acquired loans	500,000
Loans acquired with deteriorated credit quality related to allowance for loan losses	500,000	1,600,000
Management [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans to directors, executive officers and affiliates	16,000,000	16,200,000
Loans to directors, executive officers and affiliates, current year additions	47,600,000	35,100,000
Loans to directors, executive officers and affiliates, current year reductions	47,800,000	33,500,000
Commercial Loan Portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum value of loan requires executive and senior officer approval	1,500,000
Minimum due period of loans consider in a nonperforming status	90 days
Loans acquired with deteriorated credit quality related to allowance for loan losses	0	1,200,000
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Original contractual terms	90 days
Minimum due period of loans consider in a nonperforming status	90 days
Loans acquired with deteriorated credit quality related to allowance for loan losses	500,000	400,000
Acquired Portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Loans	9,100,000	17,400,000
Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum value of loan requires group loan authority approval	1,000,000
Maximum value of loan requires executive and senior officer approval	3,500,000
Real Estate Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period for loan secured under real estate residential security	15 years
Loan-to-value ratio at the time of origination	80.00%
Loans held-for-sale, recorded investment sold	305,000,000	219,000,000
Land Development Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum period for payment of loan	12 months
Maximum [Member] | Commercial Loan Portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum value of loan requires group loan authority approval	5,000,000
Other loans requiring director loan committee approval depending on risk rating and credit action required	5,000,000
Maximum [Member] | Real Estate Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Upper limit of number of family residential properties	4
Minimum [Member] | Commercial Loan Portfolio [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum value of loan requires group loan authority approval	1,000,000
Minimum value of loans requiring board of directors approval	10,000,000
Minimum [Member] | Commercial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum value of loan requiring director loan committee approval	5,000,000
Minimum [Member] | Real Estate Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lower limit of number of family residential properties	1
Fixed-Rate Real Estate Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held-for-sale	17,700,000	18,800,000
Performing [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired Loans	$ 31,400,000	$ 20,400,000