Segment information - Schedule of Reported Revenue and Pre-Tax Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Revenue
Revenue	$ 445,095	$ 367,825
Less :
Compensation expenses (1)	296,001	227,091
Other Segment Items	176,095	99,358
Pre-tax income (loss)	(27,001)	41,376
Corporate/Other
Revenue
Revenue	2,293	2,578
Less :
Compensation expenses (1)	27,562	20,099
Other Segment Items	80,727	3,870
Pre-tax income (loss)	(105,996)	(21,391)
Wealth Management | Operating Segments
Revenue
Revenue	253,680	241,986
Less :
Compensation expenses (1)	155,800	119,648
Other Segment Items	54,326	54,474
Pre-tax income (loss)	43,554	67,864
Wealth Management | Operating Segments | Stock Appreciation Rights (SARs)
Less :
Compensation expenses (1)	22,300	2,700
Capital Markets | Operating Segments
Revenue
Revenue	189,122	123,261
Less :
Compensation expenses (1)	112,639	87,344
Other Segment Items	41,042	41,014
Pre-tax income (loss)	$ 35,441	$ (5,097)