FAIR VALUE MEASUREMENTS - Segregation of All Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2025	Mar. 31, 2025
Assets:
Short-term investments	$ 10.1	$ 9.4
Total financial assets	1,889.6	1,282.1
Liabilities:
Long-term debt, net, Convertible notes	31.1	28.5
Total financial liabilities	31.1	28.6
Money market funds
Assets:
Cash and cash equivalents	1,506.8	842.6
Restricted cash and cash equivalents	11.9	12.0
Restricted cash and cash equivalents, long term	76.7	88.2
Bank-time deposits
Assets:
Cash and cash equivalents	251.1	296.4
Short-term investments	10.1	9.4
Restricted cash and cash equivalents	1.6	1.9
Private equity
Assets:
Private equity	25.6	24.3
Equity securities
Assets:
Private equity	5.7	7.3
Foreign currency forward contracts
Assets:
Foreign currency forward contracts	0.1
Liabilities:
Foreign currency forward contracts	0.1
Quoted prices in active markets for identical assets (level 1)
Assets:
Total financial assets	1,863.9	1,257.8
Liabilities:
Long-term debt, net, Convertible notes	0.0	0.0
Total financial liabilities	0.0	0.0
Quoted prices in active markets for identical assets (level 1) | Money market funds
Assets:
Cash and cash equivalents	1,506.8	842.6
Restricted cash and cash equivalents	11.9	12.0
Restricted cash and cash equivalents, long term	76.7	88.2
Quoted prices in active markets for identical assets (level 1) | Bank-time deposits
Assets:
Cash and cash equivalents	251.1	296.4
Short-term investments	10.1	9.4
Restricted cash and cash equivalents	1.6	1.9
Quoted prices in active markets for identical assets (level 1) | Private equity
Assets:
Private equity	0.0	0.0
Quoted prices in active markets for identical assets (level 1) | Equity securities
Assets:
Private equity	5.7	7.3
Quoted prices in active markets for identical assets (level 1) | Foreign currency forward contracts
Assets:
Foreign currency forward contracts	0.0
Liabilities:
Foreign currency forward contracts	0.0
Significant other observable inputs (level 2)
Assets:
Total financial assets	0.1	0.0
Liabilities:
Long-term debt, net, Convertible notes	31.1	28.5
Total financial liabilities	31.1	28.6
Significant other observable inputs (level 2) | Money market funds
Assets:
Cash and cash equivalents	0.0	0.0
Restricted cash and cash equivalents	0.0	0.0
Restricted cash and cash equivalents, long term	0.0	0.0
Significant other observable inputs (level 2) | Bank-time deposits
Assets:
Cash and cash equivalents	0.0	0.0
Short-term investments	0.0	0.0
Restricted cash and cash equivalents	0.0	0.0
Significant other observable inputs (level 2) | Private equity
Assets:
Private equity	0.0	0.0
Significant other observable inputs (level 2) | Equity securities
Assets:
Private equity	0.0	0.0
Significant other observable inputs (level 2) | Foreign currency forward contracts
Assets:
Foreign currency forward contracts	0.1
Liabilities:
Foreign currency forward contracts	0.1
Significant unobservable inputs (level 3)
Assets:
Total financial assets	25.6	24.3
Liabilities:
Long-term debt, net, Convertible notes	0.0	0.0
Total financial liabilities	0.0	0.0
Significant unobservable inputs (level 3) | Money market funds
Assets:
Cash and cash equivalents	0.0	0.0
Restricted cash and cash equivalents	0.0	0.0
Restricted cash and cash equivalents, long term	0.0	0.0
Significant unobservable inputs (level 3) | Bank-time deposits
Assets:
Cash and cash equivalents	0.0	0.0
Short-term investments	0.0	0.0
Restricted cash and cash equivalents	0.0	0.0
Significant unobservable inputs (level 3) | Private equity
Assets:
Private equity	25.6	24.3
Significant unobservable inputs (level 3) | Equity securities
Assets:
Private equity	0.0	$ 0.0
Significant unobservable inputs (level 3) | Foreign currency forward contracts
Assets:
Foreign currency forward contracts	0.0
Liabilities:
Foreign currency forward contracts	$ 0.0