Portfolio Loans and allowance for credit losses - Analysis of loans past due and still accruing or non-accrual status (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans past due
90+Days	$ 1,149	$ 1,371
Non-accrual Loans	21,706	22,930
30 to 59 Days
Loans past due
Loans past due, still accruing	6,685	6,794
60 to 89 Days
Loans past due
Loans past due, still accruing	3,244	784
Commercial
Loans past due
Non-accrual Loans	7,949	8,523
Commercial | 30 to 59 Days
Loans past due
Loans past due, still accruing	52	243
Commercial | 60 to 89 Days
Loans past due
Loans past due, still accruing	2,614
Commercial real estate
Loans past due
Non-accrual Loans	5,164	5,503
Commercial real estate | 30 to 59 Days
Loans past due
Loans past due, still accruing	4,377
Real estate construction
Loans past due
Non-accrual Loans		1
Real estate construction | 30 to 59 Days
Loans past due
Loans past due, still accruing		237
Real estate construction | 60 to 89 Days
Loans past due
Loans past due, still accruing		235
Retail Real Estate
Loans past due
90+Days	1,149	1,305
Non-accrual Loans	8,495	8,799
Retail Real Estate | 30 to 59 Days
Loans past due
Loans past due, still accruing	2,248	6,248
Retail Real Estate | 60 to 89 Days
Loans past due
Loans past due, still accruing	621	400
Retail Other
Loans past due
90+Days		66
Non-accrual Loans	98	104
Retail Other | 30 to 59 Days
Loans past due
Loans past due, still accruing	8	66
Retail Other | 60 to 89 Days
Loans past due
Loans past due, still accruing	$ 9	$ 149