Revenues from contracts with customers (Contract Assets and Liabilities) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	$ 25,108	$ 37,192
Deferred revenue (payables)	2,010	235
Commission
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	3,912	2,886
Mutual Fund Income
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	5,636	6,205
Advisory fees
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	3,909	4,546
Bank Deposit Sweep Income
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	4,258	595
Investment Banking Fees
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	4,418	17,765
Other
Capitalized Contract Cost [Line Items]
Contract assets (receivables)	2,975	5,195
Investment Banking Fees
Capitalized Contract Cost [Line Items]
Deferred revenue (payables)	481	235
IRA fees
Capitalized Contract Cost [Line Items]
Deferred revenue (payables)	$ 1,529	$ 0