Segment information - Reported Revenue and Profit Before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenue
Total	$ 353,138	$ 321,679
Pre-Tax Income (Loss)
Total pre-tax income (loss)	37,455	19,049
Corporate/Other
Revenue
Total	3,094	4,017
Pre-Tax Income (Loss)
Total pre-tax income (loss)	$ (31,628)	$ (26,411)
Private Client
Pre-Tax Income (Loss)
Asset management fees (as a percent)	90.00%	90.00%
Private Client | Operating Segments
Revenue
Total	$ 213,033	$ 203,421
Pre-Tax Income (Loss)
Total pre-tax income (loss)	$ 68,151	$ 54,456
Asset Management
Pre-Tax Income (Loss)
Asset management fees (as a percent)	10.00%	10.00%
Asset Management | Operating Segments
Revenue
Total	$ 24,928	$ 23,959
Pre-Tax Income (Loss)
Total pre-tax income (loss)	7,634	6,481
Capital markets | Operating Segments
Revenue
Total	112,083	90,282
Pre-Tax Income (Loss)
Total pre-tax income (loss)	$ (6,702)	$ (15,477)