Fair Value - Summary of Valuation of Financial Instruments by Pricing Observability Levels (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2026	Dec. 31, 2025
Assets, Fair Value Disclosure [Abstract]
Derivative Liability, Statement Of Financial Position, Extensible Enumeration, Not Disclosed Flag	Derivatives	Derivatives
Contingent consideration liability	$ 8,647	$ 8,605
Recurring
Assets, Fair Value Disclosure [Abstract]
Money markets	111,611	175,029
Securities segregated (U.S. Treasury Bills)	350,133	498,649
Derivatives	19,718	12,985
Total assets measured at fair value and other measurements	667,528	907,566
Derivatives	14,109	17,615
Contingent consideration liability	8,647	8,605
Total liabilities measured at fair value	22,756	26,220
Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	178,019	211,900
Recurring | Other investments
Assets, Fair Value Disclosure [Abstract]
Total investments	8,047	9,003
Level 1 | Recurring
Assets, Fair Value Disclosure [Abstract]
Money markets	111,611	175,029
Securities segregated (U.S. Treasury Bills)	0	0
Derivatives	3,645	832
Total assets measured at fair value	246,795	330,081
Derivatives	97	366
Contingent consideration liability	0	0
Total liabilities measured at fair value	97	366
Level 1 | Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	123,492	145,217
Level 1 | Recurring | Other investments
Assets, Fair Value Disclosure [Abstract]
Other investments	8,047	9,003
Level 2 | Recurring
Assets, Fair Value Disclosure [Abstract]
Money markets	0	0
Securities segregated (U.S. Treasury Bills)	350,133	498,649
Derivatives	16,073	12,153
Total assets measured at fair value	420,574	577,321
Derivatives	14,012	17,249
Contingent consideration liability	0	0
Total liabilities measured at fair value	14,012	17,249
Level 2 | Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	54,368	66,519
Level 2 | Recurring | Other investments
Assets, Fair Value Disclosure [Abstract]
Other investments	0	0
Level 3 | Recurring
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	123	127
Derivatives	0	0
Contingent consideration liability	8,647	8,605
Total liabilities measured at fair value	8,647	8,605
Level 3 | Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	123	127
Level 3 | Recurring | Other investments
Assets, Fair Value Disclosure [Abstract]
Other investments	0	0
NAV Expedient | Recurring
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	36	37
Derivatives	0	0
Contingent consideration liability	0	0
Total liabilities measured at fair value	0	0
NAV Expedient | Recurring | Equity securities
Assets, Fair Value Disclosure [Abstract]
Equity securities	36	37
NAV Expedient | Recurring | Other investments
Assets, Fair Value Disclosure [Abstract]
Other investments	$ 0	$ 0