Segment and Geographic Information - Schedule of Product Information Regarding Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Segment Reporting Information [Line Items]
Total revenues	$ 664,240	$ 578,614
Fees from related parties	4,422	4,421
Data, software, and post-trade	32,500	30,903
Interest and dividend income	11,629	9,764
Other revenues	4,900	5,505
Compensation and employee benefits	341,648	290,842
Equity-based compensation and allocations of net income to limited partnership units and FPUs	75,323	96,081
Total compensation and employee benefits	416,971	386,923
Consolidated net income (loss)	53,429	49,041
Reportable Segment
Segment Reporting Information [Line Items]
Total revenues	664,240	578,614
Fees from related parties	4,422	4,421
Data, software, and post-trade	32,500	30,903
Interest and dividend income	11,629	9,764
Other revenues	4,900	5,505
Compensation and employee benefits	341,648	290,842
Equity-based compensation and allocations of net income to limited partnership units and FPUs	75,323	96,081
Total compensation and employee benefits	416,971	386,923
Other segment items	193,840	142,650
Consolidated net income (loss)	53,429	49,041
Interest income	11,600	9,800
Depreciation and intangible amortization	21,900	20,600
Reportable Segment | Total brokerage revenues
Segment Reporting Information [Line Items]
Total revenues	610,789	528,021
Reportable Segment | Rates
Segment Reporting Information [Line Items]
Total revenues	200,945	175,085
Reportable Segment | ECS
Segment Reporting Information [Line Items]
Total revenues	149,937	118,464
Reportable Segment | FX
Segment Reporting Information [Line Items]
Total revenues	110,035	84,023
Reportable Segment | Credit
Segment Reporting Information [Line Items]
Total revenues	86,936	87,592
Reportable Segment | Equities
Segment Reporting Information [Line Items]
Total revenues	62,936	62,857
Reportable Segment | Total other revenues
Segment Reporting Information [Line Items]
Total revenues	$ 53,451	$ 50,593