Loans and Credit Quality - Newly Restructured Loans by Concession (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($) contract
Financing Receivable, Modifications [Line Items]
Pre-modification, number of contracts | contract	2
Pre-modification, total modification	$ 10,875
Post-modification, number of contracts | contract	2
Post-modification, total modification	$ 10,375
Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, number of contracts | contract	2
Pre-modification, total modification	$ 10,875
Post-modification, number of contracts | contract	2
Post-modification, total modification	$ 10,375
Rate Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0
Post-modification, total modification	0
Rate Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0
Post-modification, total modification	0
Term Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	10,665
Post-modification, total modification	10,165
Term Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	10,665
Post-modification, total modification	10,165
Payment Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	210
Post-modification, total modification	210
Payment Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	210
Post-modification, total modification	210
Combination Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0
Post-modification, total modification	0
Combination Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0
Post-modification, total modification	$ 0