Loans and Credit Quality - Restructured Loans (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	$ 3,432
Existing Troubled Debt Restructurings	14,430
Total	17,862	$ 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	0
Existing Troubled Debt Restructurings	3,252
Total	3,252
Accrual Status | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	0
Accrual Status | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	0
Nonaccrual Status
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	3,432
Existing Troubled Debt Restructurings	11,178
Total	14,610
Nonaccrual Status | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	1,738
Nonaccrual Status | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	$ 1,694