v3.26.3
Fair Value - Summary of Valuation of Financial Instruments by Pricing Observability Levels (Details) - USD ($)
$ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2026
Dec. 31, 2025
Assets, Fair Value Disclosure [Abstract]    
Money markets $ 82,295 $ 175,029
Securities segregated (U.S. Treasury Bills) 379,188 498,649
Derivatives 21,340 12,985
Total assets measured at fair value and other measurements 838,673 907,566
Derivatives $ 15,787 $ 17,615
Derivative Liability, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag Derivatives Derivatives
Contingent consideration liability $ 8,732 $ 8,605
Total liabilities measured at fair value 24,519 26,220
Recurring    
Assets, Fair Value Disclosure [Abstract]    
Total investments 355,850  
U.S. Treasury Bills    
Assets, Fair Value Disclosure [Abstract]    
Total investments 209,414  
Equity securities    
Assets, Fair Value Disclosure [Abstract]    
Equity securities 137,923 211,900
Other investments    
Assets, Fair Value Disclosure [Abstract]    
Total investments 8,513 9,003
Level 1    
Assets, Fair Value Disclosure [Abstract]    
Money markets 82,295 175,029
Securities segregated (U.S. Treasury Bills) 0 0
Derivatives 4,286 832
Total assets measured at fair value 189,739 330,081
Derivatives 194 366
Contingent consideration liability 0 0
Total liabilities measured at fair value 194 366
Level 1 | Recurring    
Assets, Fair Value Disclosure [Abstract]    
Investments 103,158  
Level 1 | U.S. Treasury Bills    
Assets, Fair Value Disclosure [Abstract]    
Investments 0  
Level 1 | Equity securities    
Assets, Fair Value Disclosure [Abstract]    
Equity securities 94,645 145,217
Level 1 | Other investments    
Assets, Fair Value Disclosure [Abstract]    
Investments 8,513 9,003
Level 2    
Assets, Fair Value Disclosure [Abstract]    
Money markets 0 0
Securities segregated (U.S. Treasury Bills) 379,188 498,649
Derivatives 17,054 12,153
Total assets measured at fair value 647,768 577,321
Derivatives 15,593 17,249
Contingent consideration liability 0 0
Total liabilities measured at fair value 15,593 17,249
Level 2 | Recurring    
Assets, Fair Value Disclosure [Abstract]    
Investments 251,526  
Level 2 | U.S. Treasury Bills    
Assets, Fair Value Disclosure [Abstract]    
Investments 209,414  
Level 2 | Equity securities    
Assets, Fair Value Disclosure [Abstract]    
Equity securities 42,112 66,519
Level 2 | Other investments    
Assets, Fair Value Disclosure [Abstract]    
Investments 0 0
Level 3    
Assets, Fair Value Disclosure [Abstract]    
Money markets 0 0
Securities segregated (U.S. Treasury Bills) 0 0
Derivatives 0 0
Total assets measured at fair value 126 127
Derivatives 0 0
Contingent consideration liability 8,732 8,605
Total liabilities measured at fair value 8,732 8,605
Level 3 | Recurring    
Assets, Fair Value Disclosure [Abstract]    
Investments 126  
Level 3 | U.S. Treasury Bills    
Assets, Fair Value Disclosure [Abstract]    
Investments 0  
Level 3 | Equity securities    
Assets, Fair Value Disclosure [Abstract]    
Equity securities 126 127
Level 3 | Other investments    
Assets, Fair Value Disclosure [Abstract]    
Investments 0 0
NAV Expedient    
Assets, Fair Value Disclosure [Abstract]    
Money markets 0 0
Securities segregated (U.S. Treasury Bills) 0 0
Derivatives 0 0
Total assets measured at fair value 1,040 37
Derivatives 0 0
Contingent consideration liability 0 0
Total liabilities measured at fair value 0 0
NAV Expedient | Recurring    
Assets, Fair Value Disclosure [Abstract]    
Investments 1,040  
NAV Expedient | U.S. Treasury Bills    
Assets, Fair Value Disclosure [Abstract]    
Investments 0  
NAV Expedient | Equity securities    
Assets, Fair Value Disclosure [Abstract]    
Equity securities 1,040 37
NAV Expedient | Other investments    
Assets, Fair Value Disclosure [Abstract]    
Investments $ 0 $ 0