v3.26.1
Intangible Assets, net - Schedule of Intangible Assets (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2026
Sep. 30, 2025
Dec. 31, 2025
Finite-Lived Intangible Assets [Line Items]      
Gross Carrying Amount $ 307,837   $ 309,172
Impairment/Disposals     (600)
Accumulated Amortization (42,523)   (38,419)
Net Carrying Amount 265,314   270,153
Foreign currency translation differences (700)   4,100
Non-amortized intangible assets      
Gross Carrying Amount 166,004   201,004
Impairment/Disposals     (35,000)
Net Carrying Amount 166,004   166,004
Intangible Assets, Gross Carrying Amount 473,841   510,176
Intangible Assets, Impairment     (35,600)
Intangible Assets, Net Carrying Amount 431,318   436,157
Kontora Family Office GmbH ("Kontora")      
Finite-Lived Intangible Assets [Line Items]      
Intangible assets acquired     14,800
Adjustments to intangibles     (700)
Other intangible asset      
Non-amortized intangible assets      
Gross Carrying Amount 4   4
Impairment/Disposals     0
Net Carrying Amount 4   4
Investment management agreements      
Non-amortized intangible assets      
Gross Carrying Amount 166,000   201,000
Impairment/Disposals   $ (35,000)  
Net Carrying Amount $ 166,000   $ 166,000
Customer relationships      
Finite-Lived Intangible Assets [Line Items]      
Weighted Average Amortization Period (in years) 22 years 1 month 6 days   22 years
Gross Carrying Amount $ 289,778   $ 290,419
Impairment/Disposals     0
Accumulated Amortization (36,886)   (33,235)
Net Carrying Amount $ 252,892   $ 257,184
Trade names      
Finite-Lived Intangible Assets [Line Items]      
Weighted Average Amortization Period (in years) 9 years 4 months 24 days   9 years 3 months 18 days
Gross Carrying Amount $ 12,235   $ 12,238
Impairment/Disposals     0
Accumulated Amortization (4,177)   (3,828)
Net Carrying Amount $ 8,058   $ 8,410
License      
Finite-Lived Intangible Assets [Line Items]      
Weighted Average Amortization Period (in years) 15 years   15 years
Gross Carrying Amount $ 4,444   $ 4,535
Impairment/Disposals     0
Accumulated Amortization (271)   (195)
Net Carrying Amount $ 4,173   $ 4,340
Acquired internally developed software      
Finite-Lived Intangible Assets [Line Items]      
Weighted Average Amortization Period (in years) 5 years   5 years
Gross Carrying Amount $ 700   $ 1,300
Impairment/Disposals     (600)
Accumulated Amortization (520)   (505)
Net Carrying Amount $ 180   $ 195
Other intangible asset      
Finite-Lived Intangible Assets [Line Items]      
Weighted Average Amortization Period (in years) 2 years   1 year 6 months
Gross Carrying Amount $ 680   $ 680
Impairment/Disposals     0
Accumulated Amortization (669)   (656)
Net Carrying Amount $ 11   $ 24