Loans and Credit Quality - Restructured Loans (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	$ 11,382
Existing Troubled Debt Restructurings	14,586
Total	25,968	$ 16,200
Commercial | AQR Special Mention
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	2,078
Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	9,304
Accrual Status
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	2,283
Existing Troubled Debt Restructurings	5,404
Total	7,687
Accrual Status | Commercial | AQR Special Mention
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	2,078
Accrual Status | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	205
Nonaccrual Status
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	9,099
Existing Troubled Debt Restructurings	9,182
Total	18,281
Nonaccrual Status | Commercial | AQR Special Mention
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	0
Nonaccrual Status | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
New Troubled Debt Restructurings	$ 9,099