Allowance for credit losses - Financial effect of the modifications made to borrowers experiencing financial difficultie (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Interest Rate Reduction \| Mortgages
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification	6.10%	5.80%
Weighted average contractual interest rate after modification	4.40%	4.20%
Interest Rate Reduction \| Commercial \| Commercial multi-family
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification		7.50%
Weighted average contractual interest rate after modification		5.30%
Interest Rate Reduction \| Commercial \| CRE non-owner occupied
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification	10.10%	9.10%
Weighted average contractual interest rate after modification	8.30%	7.30%
Interest Rate Reduction \| Commercial \| CRE owner occupied
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification	6.70%	8.40%
Weighted average contractual interest rate after modification	5.80%	6.60%
Interest Rate Reduction \| Commercial \| Commercial and industrial
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification	21.60%	17.80%
Weighted average contractual interest rate after modification	9.60%	7.80%
Interest Rate Reduction \| Consumer \| Credit card
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification	21.20%	18.80%
Weighted average contractual interest rate after modification	7.60%	4.50%
Interest Rate Reduction \| Consumer \| Personal loans
Financing Receivable, Modifications [Line Items]
Weighted average contractual interest rate before modification	19.80%	17.80%
Weighted average contractual interest rate after modification	10.60%	9.30%
Interest Rate Reduction \| Consumer \| Auto Loan
Financing Receivable, Modifications [Line Items]
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, Modifications [Line Items]
Weighted average contractual interest rate before modification	18.00%	18.00%
Weighted average contractual interest rate after modification	0.00%	0.00%
Term extension \| Construction
Financing Receivable, Modifications [Line Items]
Weighted average term increase	2 months	1 year
Term extension \| Mortgages
Financing Receivable, Modifications [Line Items]
Weighted average term increase	12 years	11 years
Term extension \| Commercial \| Commercial multi-family
Financing Receivable, Modifications [Line Items]
Weighted average term increase	4 months	43 years
Term extension \| Commercial \| CRE non-owner occupied
Financing Receivable, Modifications [Line Items]
Weighted average term increase	1 year	20 months
Term extension \| Commercial \| CRE owner occupied
Financing Receivable, Modifications [Line Items]
Weighted average term increase	21 months	1 year
Term extension \| Commercial \| Commercial and industrial
Financing Receivable, Modifications [Line Items]
Weighted average term increase	21 months	2 years
Term extension \| Consumer \| Personal loans
Financing Receivable, Modifications [Line Items]
Weighted average term increase	7 years	8 years
Term extension \| Consumer \| Auto Loan
Financing Receivable, Modifications [Line Items]
Weighted average term increase	3 years	2 years
Principal Forgiveness \| Commercial \| CRE owner occupied
Financing Receivable, Modifications [Line Items]
Reduced the amortized cost basis		$ 88
Other-Than-Insignificant Payment Delays \| Mortgages
Financing Receivable, Modifications [Line Items]
Weighted average term increase	53 months	40 months
Other-Than-Insignificant Payment Delays \| Commercial \| CRE non-owner occupied
Financing Receivable, Modifications [Line Items]
Weighted average term increase	13 months	11 months
Other-Than-Insignificant Payment Delays \| Commercial \| CRE owner occupied
Financing Receivable, Modifications [Line Items]
Weighted average term increase	6 months	9 months
Other-Than-Insignificant Payment Delays \| Commercial \| Commercial and industrial
Financing Receivable, Modifications [Line Items]
Weighted average term increase	12 months	7 months
Other-Than-Insignificant Payment Delays \| Consumer \| Credit card
Financing Receivable, Modifications [Line Items]
Weighted average term increase	16 months	25 months

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage, after modification, of weighted-average interest rate of financing receivable for debtor experiencing financial difficulty.

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Percentage, before modification, of weighted-average interest rate of financing receivable for debtor experiencing financial difficulty.

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Period of increase in weighted average maturity of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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