Revenue from contracts with customers - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	$ 72,794	$ 46,187
Deferred revenue (payables)	2,132	930
Investment banking fees
Contracts with Customers Assets and Liabilities [Line Items]
Deferred revenue (payables)	286	28
Software license fees
Contracts with Customers Assets and Liabilities [Line Items]
Deferred revenue (payables)	1,846	902
Commission
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	5,011	4,408
Mutual fund and insurance income
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	6,106	5,838
Advisory fees
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	24,166	11,271
Bank deposit sweep income
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	3,876	4,748
Investment banking fees
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	25,414	14,798
Other
Contracts with Customers Assets and Liabilities [Line Items]
Total receivables	$ 8,221	$ 5,124