Loan Portfolio and Credit Quality Nonaccrual Loans by Class of Financing Receivable (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	$ 17,155	$ 14,057
Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	1,567	2,554
Commercial tax-exempt
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	0	0
Total commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	1,567	2,554
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	0	546
Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	12,572	7,914
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	3,004	3,031
Consumer and other
Financing Receivable, Credit Quality Indicator [Line Items]
Nonaccrual loan receivable	$ 12	$ 12