Loans (Nonaccrual Loans) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 22,543	$ 21,237
Accruing loans 90 days or more past due	0	0
Nonaccrual loans, interest income lost	1,800	1,700	1,300
Nonaccrual loans, interest income recorded	679	505	831
Current Payment Status [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans, current as to payment of principal and interest	1,600	3,600
Commercial Mortgages [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	10,681	5,709
Commercial Construction and Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	0	0
Commercial Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	4,412	3,708
Residential Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	6,158	10,614
Homeowner Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	0	0
Home Equity Lines [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	840	718
Home Equity Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	371	335
Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual loans	$ 81	$ 153