v3.26.1
FAIR VALUE MEASUREMENT -Fair Value Hierarchy for Assets and Liabilities on a Recurring Basis (Details) - Fair Value, Recurring - USD ($)
$ in Millions
Jun. 30, 2026
Dec. 31, 2025
Assets:    
Digital assets held $ 0.4  
Total assets 1,832.1 $ 1,578.3
Money market funds    
Assets:    
Investments 6.2 7.3
US Treasury Securities    
Assets:    
Investments 74.5 0.3
Mutual funds    
Assets:    
Investments 33.8 28.5
US And UK Treasury securities    
Assets:    
Cash and cash equivalents 1,452.4 1,294.1
Money market funds    
Assets:    
Cash and cash equivalents 264.8 248.1
Level 1    
Assets:    
Digital assets held 0.0  
Total assets 1,831.7 1,578.3
Level 1 | Money market funds    
Assets:    
Investments 6.2 7.3
Level 1 | US Treasury Securities    
Assets:    
Investments 74.5 0.3
Level 1 | Mutual funds    
Assets:    
Investments 33.8 28.5
Level 1 | US And UK Treasury securities    
Assets:    
Cash and cash equivalents 1,452.4 1,294.1
Level 1 | Money market funds    
Assets:    
Cash and cash equivalents 264.8 248.1
Level 2    
Assets:    
Digital assets held 0.4  
Total assets 0.4 0.0
Level 2 | Money market funds    
Assets:    
Investments 0.0 0.0
Level 2 | US Treasury Securities    
Assets:    
Investments 0.0 0.0
Level 2 | Mutual funds    
Assets:    
Investments 0.0 0.0
Level 2 | US And UK Treasury securities    
Assets:    
Cash and cash equivalents 0.0 0.0
Level 2 | Money market funds    
Assets:    
Cash and cash equivalents 0.0 0.0
Level 3    
Assets:    
Digital assets held 0.0  
Total assets 0.0 0.0
Level 3 | Money market funds    
Assets:    
Investments 0.0 0.0
Level 3 | US Treasury Securities    
Assets:    
Investments 0.0 0.0
Level 3 | Mutual funds    
Assets:    
Investments 0.0 0.0
Level 3 | US And UK Treasury securities    
Assets:    
Cash and cash equivalents 0.0 0.0
Level 3 | Money market funds    
Assets:    
Cash and cash equivalents $ 0.0 $ 0.0