Revenue from contracts with customers - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	$ 32,773	$ 37,192
Total deferred revenue	900	235
Investment banking fees
Contracts with Customers Assets and Liabilities [Line Items]
Total deferred revenue	900	235
Commission
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	3,533	2,886
Mutual fund income
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	4,993	6,205
Advisory fees
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	5,368	4,546
Bank deposit sweep income
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	9,057	595
Investment banking fees
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	5,136	17,765
Other
Contracts with Customers Assets and Liabilities [Line Items]
Total contract assets	$ 4,686	$ 5,195