Allowance for credit losses - Financial effect of the modifications made to borrowers experiencing financial difficultie (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Financing Receivable
Reduced the amortized cost basis		$ 3,190
Mortgages
Financing Receivable
Reduced the amortized cost basis		1,020
Commercial | CRE non-owner occupied
Financing Receivable
Reduced the amortized cost basis		0
Commercial | CRE owner occupied
Financing Receivable
Reduced the amortized cost basis		0
Consumer | Credit card
Financing Receivable
Reduced the amortized cost basis		5
Consumer | Personal loans
Financing Receivable
Reduced the amortized cost basis		130
Consumer | Auto Loan
Financing Receivable
Reduced the amortized cost basis		5
Consumer | Other
Financing Receivable
Reduced the amortized cost basis		0
Leasing
Financing Receivable
Reduced the amortized cost basis		$ 0
Interest Rate Reduction | Mortgages
Financing Receivable
Weighted average contractual interest rate before modification	5.69%
Weighted average contractual interest rate after modification	4.17%
Interest Rate Reduction | Commercial | CRE owner occupied
Financing Receivable
Weighted average contractual interest rate before modification	6.00%
Weighted average contractual interest rate after modification	5.25%
Interest Rate Reduction | Consumer | Credit card
Financing Receivable
Weighted average contractual interest rate before modification	17.76%
Weighted average contractual interest rate after modification	4.47%
Interest Rate Reduction | Consumer | Personal loans
Financing Receivable
Weighted average contractual interest rate before modification	16.97%
Weighted average contractual interest rate after modification	9.11%
Interest Rate Reduction | Consumer | Auto Loan
Financing Receivable
Weighted average contractual interest rate before modification	12.64%
Weighted average contractual interest rate after modification	12.62%
Interest Rate Reduction | Consumer | Other
Financing Receivable
Weighted average contractual interest rate before modification	17.99%
Weighted average contractual interest rate after modification	0.00%
Term Extension | Construction
Financing Receivable
Weighted average term increase	6 months
Term Extension | Mortgages
Financing Receivable
Weighted average term increase	10 years
Term Extension | Commercial | CRE owner occupied
Financing Receivable
Weighted average term increase	2 years
Term Extension | Commercial | Commercial and industrial
Financing Receivable
Weighted average term increase	5 months
Term Extension | Consumer | Personal loans
Financing Receivable
Weighted average term increase	6 years
Term Extension | Consumer | Auto Loan
Financing Receivable
Weighted average term increase	2 years
Other-Than-Insignificant Payment Delays | Commercial | CRE non-owner occupied
Financing Receivable
Weighted average term increase	12 months
Other-Than-Insignificant Payment Delays | Commercial | CRE owner occupied
Financing Receivable
Weighted average term increase	7 months
Other-Than-Insignificant Payment Delays | Commercial | Commercial and industrial
Financing Receivable
Weighted average term increase	9 months
Other-Than-Insignificant Payment Delays | Consumer | Other
Financing Receivable
Weighted average term increase	11 months