Revenue from contracts with customers - Schedule of Receivables and Deferred Revenue Balances from Contracts with Customers (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	$ 45,252	$ 46,187
Deferred revenue (payables)	3,344	930
Investment Banking fees
Capitalized Contract Cost [Line Items]
Deferred revenue (payables)	184	28
Software license fees
Capitalized Contract Cost [Line Items]
Deferred revenue (payables)	1,960	902
IRA fees
Capitalized Contract Cost [Line Items]
Deferred revenue (payables)	1,200	0
Commission
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	8,918	4,408
Mutual fund and insurance income
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	5,575	5,838
Advisory fees
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	5,596	11,271
Bank deposit sweep income
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	4,348	4,748
Investment Banking fees
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	13,428	14,798
Other
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	$ 7,387	$ 5,124