v3.25.2
Note 6 - Fair Value Measurements - Level of Fair Value (Details) - USD ($)
$ in Millions
 6 Months Ended
Jun. 30, 2025
Dec. 31, 2024
Total investment securities $ 380.7 $ 337.1
Variable Interest Entity, Primary Beneficiary [Member]    
Total investment securities 1,059.4 502.1
Fair Value, Recurring [Member]    
Cash equivalents 578.4 821.7
Total investment securities 1,440.1 839.2
Other 7.8  
Total assets 2,026.3 1,673.6
Seed hedge derivatives 24.3  
Long-term debt 396.2 [1] 383.3 [2]
Contingent consideration 23.3 30.4
Total liabilities 547.9 543.0
Other   5.1
Fair Value, Recurring [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]    
Other   12.7
Fair Value, Recurring [Member] | Seed Hedge Derivatives [Member]    
Seed hedge derivatives 14.0 8.5
Fair Value, Recurring [Member] | Deferred Bonuses Hedge [Member]    
Seed hedge derivatives 68.0 115.7
Fair Value, Recurring [Member] | Warrants Liability [Member]    
Warrants 22.1  
Fair Value, Recurring [Member] | Other Investment Securities [Member]    
Total investment securities 380.7 337.1
Fair Value, Recurring [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Total investment securities 1,059.4 502.1
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]    
Cash equivalents 578.4 821.7
Total investment securities 722.0 534.4
Other 0.0  
Total assets 1,300.4 1,356.1
Seed hedge derivatives 3.9  
Long-term debt 0.0 [1] 0.0 [2]
Contingent consideration 0.0 0.0
Total liabilities 3.9 1.9
Other   1.9
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]    
Other   0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Seed Hedge Derivatives [Member]    
Seed hedge derivatives 0.0 0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Deferred Bonuses Hedge [Member]    
Seed hedge derivatives 0.0 0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Warrants Liability [Member]    
Warrants 0.0  
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Other Investment Securities [Member]    
Total investment securities 309.0 273.8
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 1 [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Total investment securities 413.0 260.6
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]    
Cash equivalents 0.0 0.0
Total investment securities 671.8 275.2
Other 5.7  
Total assets 677.5 285.4
Seed hedge derivatives 1.4  
Long-term debt 396.2 [1] 383.3 [2]
Contingent consideration 0.0 0.0
Total liabilities 433.7 395.0
Other   3.2
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]    
Other   10.2
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Seed Hedge Derivatives [Member]    
Seed hedge derivatives 14.0 8.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Deferred Bonuses Hedge [Member]    
Seed hedge derivatives 0.0 0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Warrants Liability [Member]    
Warrants 22.1  
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Other Investment Securities [Member]    
Total investment securities 25.4 33.7
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Total investment securities 646.4 241.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]    
Cash equivalents 0.0 0.0
Total investment securities 23.2 2.0
Other 2.1  
Total assets 25.3 4.5
Seed hedge derivatives 19.0  
Long-term debt 0.0 [1] 0.0 [2]
Contingent consideration 23.3 30.4
Total liabilities 110.3 146.1
Other   0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]    
Other   2.5
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Seed Hedge Derivatives [Member]    
Seed hedge derivatives 0.0 0.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Deferred Bonuses Hedge [Member]    
Seed hedge derivatives 68.0 115.7
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Warrants Liability [Member]    
Warrants 0.0  
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Other Investment Securities [Member]    
Total investment securities 23.2 2.0
Fair Value, Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Total investment securities 0.0 0.0
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member]    
Cash equivalents 0.0 [3] 0.0 [4]
Total investment securities 23.1 [3] 27.6 [4]
Other [3] 0.0  
Total assets 23.1 [3] 27.6 [4]
Seed hedge derivatives [3] 0.0  
Long-term debt 0.0 [1],[3] 0.0 [2],[4]
Contingent consideration 0.0 [3] 0.0 [4]
Total liabilities 0.0 [3] 0.0 [4]
Other [4]   0.0
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Derivatives Used in Consolidated Seeded Investment Products [Member]    
Other [4]   0.0
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Seed Hedge Derivatives [Member]    
Seed hedge derivatives 0.0 0.0
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Deferred Bonuses Hedge [Member]    
Seed hedge derivatives 0.0 [3] 0.0 [4]
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Warrants Liability [Member]    
Warrants 0.0  
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Other Investment Securities [Member]    
Total investment securities 23.1 [3] 27.6 [4]
Fair Value, Recurring [Member] | Fair Value Measured at Net Asset Value Per Share [Member] | Variable Interest Entity, Primary Beneficiary [Member]    
Total investment securities $ 0.0 [3] $ 0.0 [4]
[1] Carried at amortized cost in our Consolidated Balance Sheets and disclosed in this table at fair value.
[2] Carried at amortized cost in our Condensed Consolidated Balance Sheets and disclosed in this table at fair value.
[3] Certain seeded investment products that do not have a readily determinable fair value have been measured at fair value using the net asset value (“NAV”) as a practical expedient and have not been categorized in the fair value hierarchy.
[4] Certain seeded investment products that do not have a readily determinable fair value have been measured at fair value using the NAV as a practical expedient and have not been categorized in the fair value hierarchy.