Allowance for credit losses - T D R that subsequently defaulted (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) loans	Jun. 30, 2020 USD ($) loans	Jun. 30, 2021 USD ($) loans	Jun. 30, 2020 USD ($) loans
Financing Receivable
Loan count | loans	65	238	132	366
Recorded investment as of first default date | $	$ 12,285	$ 13,205	$ 18,726	$ 20,994
Mortgages
Financing Receivable
Loan count | loans	24	101	47	148
Recorded investment as of first default date | $	$ 3,279	$ 9,582	$ 5,011	$ 16,089
Commercial | CRE non-owner occupied
Financing Receivable
Loan count | loans	4	1	4	1
Recorded investment as of first default date | $	$ 8,421	$ 1,700	$ 8,421	$ 1,700
Commercial | CRE owner occupied
Financing Receivable
Loan count | loans	0	3	2	5
Recorded investment as of first default date | $	$ 0	$ 603	$ 3,754	$ 846
Commercial | Commercial and Industrial
Financing Receivable
Loan count | loans	3	1	5	3
Recorded investment as of first default date | $	$ 93	$ 57	$ 317	$ 97
Consumer | Credit card
Financing Receivable
Loan count | loans	23	82	60	123
Recorded investment as of first default date | $	$ 280	$ 652	$ 751	$ 866
Consumer | Home equity lines of credit
Financing Receivable
Loan count | loans		1		1
Recorded investment as of first default date | $		$ 31		$ 31
Consumer | Personal loans
Financing Receivable
Loan count | loans	11	48	14	83
Recorded investment as of first default date | $	$ 212	$ 579	$ 472	$ 1,364
Consumer | Other
Financing Receivable
Loan count | loans		1		2
Recorded investment as of first default date | $		$ 1		$ 1