INCOME TAXES - Reconciliation of Income Tax Expense (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Contingency [Line Items]
Income taxes based on domestic statutory rates	$ 30,961	$ 88,552	$ 63,044
Effect of tax rate differential	(135,033)	(244,128)	(85,132)
Change in liability for uncertain tax positions	(15,381)	22,180	684
Change in valuation allowance	191,896	297,330	78,728
Recognition of prior year taxes recoverable	5,439	(53,757)	0
Expiration of tax attributes	4,277	0	0
Other	6,568	(17,818)	(6,040)
Provision for income taxes	88,727	92,359	51,284
Income resulting from tax holidays and tax incentives	$ 24,400	$ 21,700	$ 15,500
Effect on basic loss per share due to income resulting from tax holidays and tax incentives (in dollars per share)	$ 0.05	$ 0.04	$ 0.03
Effect on diluted loss per share due to income resulting from tax holidays and tax incentives (in dollars per share)	$ 0.05	$ 0.04	$ 0.03
Expiration date of existing holidays	2028
Tax effect of foreign income not repatriated to Singapore	$ 7,500	$ 65,800	$ 67,900
Valuation Allowance and Deferred Tax Assets, Profitability Forecasted
Income Tax Contingency [Line Items]
Increase (decrease) in valuation allowance	(2,800)	(1,300)	(39,600)
Valuation Allowance and Deferred Tax Assets, Current Period Losses
Income Tax Contingency [Line Items]
Increase (decrease) in valuation allowance	$ 194,800	$ (65,900)	$ 103,900