Loans and Credit Quality - Restructured Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	$ 3,432
Existing Troubled Debt Restructurings	22,096
Total	25,528	$ 23,800
Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	1,738
Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	1,694
Accrual Status
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	1,542
Existing Troubled Debt Restructurings	7,620
Total	9,162
Accrual Status | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	1,179
Accrual Status | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	363
Nonaccrual Status
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	1,890
Existing Troubled Debt Restructurings	14,476
Total	16,366
Nonaccrual Status | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	559
Nonaccrual Status | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	$ 1,331