INCOME TAXES - CURRENT INCOME TAX (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Components of (loss) income before income taxes
Domestic	$ 136,239	$ 86,050	$ (94,174)
Foreign	386	(9,085)	55,824
Income (loss) before income taxes	136,625	76,965	(38,350)
Current:
U.S. federal	(7,327)	19,271	792
U.S. state and local	(1,266)	2,521	938
Foreign	4,208	(13,012)	(31,508)
Total current income taxes	(4,385)	8,780	(29,778)
Deferred:
U.S. federal	(13,530)	969	1,211
U.S. state and local	195	2,395	(231)
Foreign	(19,188)	(2,482)	(1,250)
Total deferred income taxes	(32,523)	882	(270)
Provision (benefit from) for income taxes	$ (36,908)	$ 9,662	$ (30,048)
Reconciliation of effective tax rate to the U.S. statutory federal income tax rate
U.S. federal statutory rate	31.60%	35.00%	35.00%
State and local taxes, net of U.S. federal benefit	0.50%	4.90%	1.60%
Foreign tax rate differential(1)	(6.90%)	(1.40%)	25.80%
Foreign earnings	1.20%	5.50%	(3.70%)
Tax credits (2)	(16.50%)	(45.80%)	98.70%
Excess tax benefits from stock-based compensation (3)	(38.90%)	0.00%	0.00%
One-time transition tax (4)	19.50%	0.00%	0.00%
Domestic production deduction	(2.80%)	(2.50%)	0.00%
Valuation allowance—domestic (5)	(0.50%)	10.10%	(77.80%)
Valuation allowance—foreign	(2.50%)	0.10%	10.40%
Change in reserves	(11.00%)	2.90%	(7.00%)
Other	(0.70%)	3.70%	(4.60%)
Effective tax rate	(27.00%)	12.50%	78.40%