Allowance for loan losses and credit quality Narrative Data (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) loans	Jun. 30, 2019 loans	Jun. 30, 2020 USD ($) loans	Jun. 30, 2019 loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of TDR loans modified within the previous twelve months that had subsequently defaulted | loans	0	0	0	0
Number of loans receiving payment deferrals | loans	406		406
Outstanding balance of loans receiving payment deferrals | $	$ 173,300		$ 173,300
Outstanding accrued interest balance of loans receiving payment deferrals | $	$ 1,600		$ 1,600