Loans, Allowance for Loan Losses, and Credit Quality Troubled Debt Restructurings Subsequent Default (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Number of Loans	155	64	69
Recorded Investment	$ 19,065	$ 9,256	$ 22,574
Commercial and Industrial Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	15	16
Recorded Investment	52	1,493	1,736
Commercial Real Estate Owner Occupied Portfolio [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3	4	10
Recorded Investment	785	542	4,729
Commercial Real Estate Investor Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	13	4	13
Recorded Investment	6,200	1,784	10,854
Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	4	5
Recorded Investment	160	80	1,695
Home Equity Portfolio Segments [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	60	14	14
Recorded Investment	2,174	1,220	2,049
Installment and Credit Cards [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3	0	1
Recorded Investment	34	0	12
Residential Portfolio Segment [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	74	23	10
Recorded Investment	$ 9,660	$ 4,137	$ 1,499