FAIR VALUE MEASUREMENTS - Recurring Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Mar. 31, 2021
Assets measured at fair value on a recurring basis
Short-term investments	$ 1,135,188	$ 1,308,692
Total recurring fair value measurements, net	2,852,030	2,976,627
Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	633,114	837,614
Restricted cash and cash equivalents	642,912	528,659
Long-term restricted cash and cash equivalents	103,433	98,541
Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	382,000	95,000
Restricted cash and cash equivalents	557	563
Short-term investments	266,869	578,762
Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	17,980	100,105
Short-term investments	150,811	148,150
US Agencies
Assets measured at fair value on a recurring basis
Cash and cash equivalents	5,000
Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	1,001	0
Short-term investments	661,790	521,224
US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	55,489	60,086
Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	229	470
Private equity
Assets measured at fair value on a recurring basis
Private equity	9,670	7,578
Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	(161)	(125)
Contingent consideration, current	(28,294)
Contingent consideration, noncurrent	(50,370)
Quoted prices in active markets for identical assets (level 1)
Assets measured at fair value on a recurring basis
Total recurring fair value measurements, net	2,084,374	2,199,225
Quoted prices in active markets for identical assets (level 1) | Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	633,114	837,614
Restricted cash and cash equivalents	642,912	528,659
Long-term restricted cash and cash equivalents	103,433	98,541
Quoted prices in active markets for identical assets (level 1) | Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	382,000	95,000
Restricted cash and cash equivalents	557	563
Short-term investments	266,869	578,762
Quoted prices in active markets for identical assets (level 1) | Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Quoted prices in active markets for identical assets (level 1) | US Agencies
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0
Quoted prices in active markets for identical assets (level 1) | Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Quoted prices in active markets for identical assets (level 1) | US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	55,489	60,086
Quoted prices in active markets for identical assets (level 1) | Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Quoted prices in active markets for identical assets (level 1) | Private equity
Assets measured at fair value on a recurring basis
Private equity	0	0
Quoted prices in active markets for identical assets (level 1) | Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	0	0
Contingent consideration, current	0
Contingent consideration, noncurrent	0
Significant other observable inputs (level 2)
Assets measured at fair value on a recurring basis
Total recurring fair value measurements, net	836,650	769,824
Significant other observable inputs (level 2) | Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Long-term restricted cash and cash equivalents	0	0
Significant other observable inputs (level 2) | Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Short-term investments	0	0
Significant other observable inputs (level 2) | Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	17,980	100,105
Short-term investments	150,811	148,150
Significant other observable inputs (level 2) | US Agencies
Assets measured at fair value on a recurring basis
Cash and cash equivalents	5,000
Significant other observable inputs (level 2) | Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	1,001	0
Short-term investments	661,790	521,224
Significant other observable inputs (level 2) | US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Significant other observable inputs (level 2) | Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	229	470
Significant other observable inputs (level 2) | Private equity
Assets measured at fair value on a recurring basis
Private equity	0	0
Significant other observable inputs (level 2) | Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	(161)	(125)
Contingent consideration, current	0
Contingent consideration, noncurrent	0
Significant unobservable inputs (level 3)
Assets measured at fair value on a recurring basis
Total recurring fair value measurements, net	(68,994)	7,578
Significant unobservable inputs (level 3) | Money market funds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Long-term restricted cash and cash equivalents	0	0
Significant unobservable inputs (level 3) | Bank-time deposits
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Restricted cash and cash equivalents	0	0
Short-term investments	0	0
Significant unobservable inputs (level 3) | Commercial paper
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Significant unobservable inputs (level 3) | US Agencies
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0
Significant unobservable inputs (level 3) | Corporate bonds
Assets measured at fair value on a recurring basis
Cash and cash equivalents	0	0
Short-term investments	0	0
Significant unobservable inputs (level 3) | US Treasuries
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Significant unobservable inputs (level 3) | Asset-backed securities
Assets measured at fair value on a recurring basis
Short-term investments	0	0
Significant unobservable inputs (level 3) | Private equity
Assets measured at fair value on a recurring basis
Private equity	9,670	7,578
Significant unobservable inputs (level 3) | Foreign currency forward contracts
Assets measured at fair value on a recurring basis
Foreign currency forward contracts	0	$ 0
Contingent consideration, current	(28,294)
Contingent consideration, noncurrent	$ (50,370)