FAIR VALUE MEASUREMENTS - ASSETS MEASURED AT FAIR VALUE (Details) - USD ($) $ in Thousands | Jun. 30, 2019 | Mar. 31, 2019 |
Assets measured at fair value on a recurring basis | | |
Short-term investments | $ 557,653 | $ 744,485 |
Restricted cash | 620,397 | 565,461 |
Total recurring fair value measurements, net | 1,838,728 | 1,766,768 |
Cross-currency swap | | |
Assets measured at fair value on a recurring basis | | |
Prepaid expenses and other | 950 | 791 |
Foreign currency forward contracts | | |
Assets measured at fair value on a recurring basis | | |
Private equity | (112) | (423) |
Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 260,752 | 296,141 |
Bank-time deposits | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 254,417 | 387,720 |
US Treasuries | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 35,448 | 55,634 |
Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 7,036 | 4,990 |
Money market funds | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 284,236 | 389,936 |
Bank-time deposits | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 150,000 | |
Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 180,196 | 39,246 |
US Treasuries | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 24,987 | 25,449 |
Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 18,598 | |
Quoted prices in active markets for identical assets (level 1) | | |
Assets measured at fair value on a recurring basis | | |
Restricted cash | 620,397 | 565,461 |
Total recurring fair value measurements, net | 1,369,485 | 1,424,200 |
Quoted prices in active markets for identical assets (level 1) | Cross-currency swap | | |
Assets measured at fair value on a recurring basis | | |
Prepaid expenses and other | 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 | | |
Private equity | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 0 | 0 |
Quoted prices in active markets for identical assets (level 1) | Bank-time deposits | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 254,417 | 387,720 |
Quoted prices in active markets for identical assets (level 1) | US Treasuries | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 35,448 | 55,634 |
Quoted prices in active markets for identical assets (level 1) | Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 0 | 0 |
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 | 284,236 | 389,936 |
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 | 150,000 | |
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 |
Quoted prices in active markets for identical assets (level 1) | US Treasuries | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 24,987 | 25,449 |
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 | |
Significant other observable inputs (level 2) | | |
Assets measured at fair value on a recurring basis | | |
Restricted cash | 0 | 0 |
Total recurring fair value measurements, net | 467,420 | 340,745 |
Significant other observable inputs (level 2) | Cross-currency swap | | |
Assets measured at fair value on a recurring basis | | |
Prepaid expenses and other | 950 | 791 |
Significant other observable inputs (level 2) | Foreign currency forward contracts | | |
Assets measured at fair value on a recurring basis | | |
Private equity | (112) | (423) |
Significant other observable inputs (level 2) | Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 260,752 | 296,141 |
Significant other observable inputs (level 2) | Bank-time deposits | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 0 | 0 |
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) | Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 7,036 | 4,990 |
Significant other observable inputs (level 2) | Money market funds | | |
Assets measured at fair value on a recurring basis | | |
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 | |
Significant other observable inputs (level 2) | Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 180,196 | 39,246 |
Significant other observable inputs (level 2) | US Treasuries | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant other observable inputs (level 2) | Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 18,598 | |
Significant unobservable inputs (level 3) | | |
Assets measured at fair value on a recurring basis | | |
Restricted cash | 0 | 0 |
Total recurring fair value measurements, net | 1,823 | 1,823 |
Significant unobservable inputs (level 3) | Cross-currency swap | | |
Assets measured at fair value on a recurring basis | | |
Prepaid expenses and other | 0 | 0 |
Significant unobservable inputs (level 3) | Foreign currency forward contracts | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 0 | 0 |
Significant unobservable inputs (level 3) | Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 0 | 0 |
Significant unobservable inputs (level 3) | Bank-time deposits | | |
Assets measured at fair value on a recurring basis | | |
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) | Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Short-term investments | 0 | 0 |
Significant unobservable inputs (level 3) | Money market funds | | |
Assets measured at fair value on a recurring basis | | |
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 | |
Significant unobservable inputs (level 3) | Commercial paper | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant unobservable inputs (level 3) | US Treasuries | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | 0 |
Significant unobservable inputs (level 3) | Corporate bonds | | |
Assets measured at fair value on a recurring basis | | |
Cash and cash equivalents | 0 | |
Other assets | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 1,823 | 1,823 |
Other assets | Quoted prices in active markets for identical assets (level 1) | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 0 | 0 |
Other assets | Significant other observable inputs (level 2) | | |
Assets measured at fair value on a recurring basis | | |
Private equity | 0 | 0 |
Other assets | Significant unobservable inputs (level 3) | | |
Assets measured at fair value on a recurring basis | | |
Private equity | $ 1,823 | $ 1,823 |