ACCUMULATED OTHER COMPREHENSIVE LOSS (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Changes in accumulated other comprehensive loss
Beginning balance	$ 2,539,244	$ 2,040,580
Ending balance	2,901,282	2,181,763
Foreign currency translation adjustments
Changes in accumulated other comprehensive loss
Beginning balance	(60,535)	(33,090)
Other comprehensive income (loss) before reclassifications	23,562	(21,364)
Amounts reclassified from accumulated other comprehensive loss	0	0
Ending balance	(36,973)	(54,454)
Unrealized gain (loss) on forward contracts
Changes in accumulated other comprehensive loss
Beginning balance	600	600
Other comprehensive income (loss) before reclassifications	0	0
Amounts reclassified from accumulated other comprehensive loss	0	0
Ending balance	600	600
Unrealized gain (loss) on cross-currency swap
Changes in accumulated other comprehensive loss
Beginning balance	4,305	(5,285)
Other comprehensive income (loss) before reclassifications	(2,972)	6,779
Amounts reclassified from accumulated other comprehensive loss	(1,333)	(3,408)
Ending balance	0	(1,914)
Unrealized gain (loss) on available-for- sales securities
Changes in accumulated other comprehensive loss
Beginning balance	(2,746)	586
Other comprehensive income (loss) before reclassifications	4,295	720
Amounts reclassified from accumulated other comprehensive loss	0	0
Ending balance	1,549	1,306
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive loss
Beginning balance	(58,376)	(37,189)
Other comprehensive income (loss) before reclassifications	24,885	(13,865)
Amounts reclassified from accumulated other comprehensive loss	(1,333)	(3,408)
Ending balance	$ (34,824)	$ (54,462)