Revenue from contracts with customers - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Contract with customer, receivables	$ 46,187	$ 39,861
Contract with Customer, Liability	930	1,118
Capitalized contract costs	$ 2,000	$ 1,900
Commission From Equity Securities Transactions
Disaggregation of Revenue [Line Items]
Revenue settlement period (in days)	1 day
Mutual fund and insurance income
Disaggregation of Revenue [Line Items]
Revenue settlement period (in days)	90 days
Advisory fees
Disaggregation of Revenue [Line Items]
Revenue settlement period (in days)	90 days
Investment banking - capital markets
Disaggregation of Revenue [Line Items]
Revenue settlement period (in days)	90 days
Bank Deposit Sweep Income
Disaggregation of Revenue [Line Items]
Revenue settlement period (in days)	30 days