Fair Value - Summary of Valuation of Financial Instruments by Pricing Observability Levels (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2026	Dec. 31, 2025
Assets, Fair Value Disclosure [Abstract]
Money markets	$ 80,111	$ 175,029
Securities segregated (U.S. Treasury Bills)	227,722	498,649
Derivatives	12,747	12,985
Total assets measured at fair value and other measurements	506,329	907,566
Derivatives	$ 17,731	$ 17,615
Derivative Liability, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag	Derivatives	Derivatives
Contingent consideration liability	$ 8,689	$ 8,605
Total liabilities measured at fair value	26,420	26,220
Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	177,267	211,900
Other investments
Assets, Fair Value Disclosure [Abstract]
Total investments	8,482	9,003
Level 1
Assets, Fair Value Disclosure [Abstract]
Money markets	80,111	175,029
Securities segregated (U.S. Treasury Bills)	0	0
Derivatives	470	832
Total assets measured at fair value	210,618	330,081
Derivatives	1,728	366
Contingent consideration liability	0	0
Total liabilities measured at fair value	1,728	366
Level 1 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	121,555	145,217
Level 1 | Other investments
Assets, Fair Value Disclosure [Abstract]
Other investments	8,482	9,003
Level 2
Assets, Fair Value Disclosure [Abstract]
Money markets	0	0
Securities segregated (U.S. Treasury Bills)	227,722	498,649
Derivatives	12,277	12,153
Total assets measured at fair value	295,545	577,321
Derivatives	16,003	17,249
Contingent consideration liability	0	0
Total liabilities measured at fair value	16,003	17,249
Level 2 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	55,546	66,519
Level 2 | Other investments
Assets, Fair Value Disclosure [Abstract]
Other 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	8,689	8,605
Total liabilities measured at fair value	8,689	8,605
Level 3 | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	126	127
Level 3 | Other investments
Assets, Fair Value Disclosure [Abstract]
Other 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	40	37
Derivatives	0	0
Contingent consideration liability	0	0
Total liabilities measured at fair value	0	0
NAV Expedient | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	40	37
NAV Expedient | Other investments
Assets, Fair Value Disclosure [Abstract]
Other investments	$ 0	$ 0