Loans and Credit Quality - Newly Restructured Loans by Concession (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($) contract	Jun. 30, 2017 USD ($) contract
Financing Receivable, Modifications [Line Items]
Pre-modification, number of contracts | contract	6	2
Pre-modification, total modification	$ 4,398	$ 10,875
Post-modification, number of contracts | contract	6	2
Post-modification, total modification	$ 3,432	$ 10,375
Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, number of contracts | contract	4	2
Pre-modification, total modification	$ 2,704	$ 10,875
Post-modification, number of contracts | contract	4	2
Post-modification, total modification	$ 1,738	$ 10,375
Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, number of contracts | contract	2
Pre-modification, total modification	$ 1,694
Post-modification, number of contracts | contract	2
Post-modification, total modification	$ 1,694
Rate Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0	0
Post-modification, total modification	0	0
Rate Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0	0
Post-modification, total modification	0	0
Rate Modification | Real estate term owner occupied | 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	0	10,665
Post-modification, total modification	0	10,165
Term Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0	10,665
Post-modification, total modification	0	10,165
Term Modification | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0
Post-modification, total modification	0
Payment Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	4,398	210
Post-modification, total modification	3,432	210
Payment Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	2,704	210
Post-modification, total modification	1,738	210
Payment Modification | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	1,694
Post-modification, total modification	1,694
Combination Modification
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0	0
Post-modification, total modification	0	0
Combination Modification | Commercial | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0	0
Post-modification, total modification	0	$ 0
Combination Modification | Real estate term owner occupied | AQR Substandard
Financing Receivable, Modifications [Line Items]
Pre-modification, total modification	0
Post-modification, total modification	$ 0