INCOME TAXES - UNCERTAIN TAX POSITIONS (Details) - USD ($)	12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Income Tax Disclosure [Abstract]
Total amount of undistributed earnings of foreign subsidiaries	$ 410,095,000	$ 314,800,000
Provision for foreign withholding taxes or U.S. income taxes, which may become payable if undistributed earnings of foreign subsidiaries are repatriated	0
Increase in interest and penalties	232,000	2,363,000	$ 877,000
Gross amount of interest and penalties accrued	6,686,000	6,453,000
Gross unrecognized tax benefits including interest and penalties	139,006,000
Gross unrealized tax benefits, which would affect effective tax rate, if realized	23,937,000
Increase in unrecognized tax benefits	10,496,000
Possible decrease in unrecognized tax benefits	11,117,000
Aggregate changes to the liability for gross uncertain tax position, excluding interest and penalties
Balance, beginning of period	122,056,000	116,085,000	52,799,000
Additions:
Current year tax positions	13,281,000	23,007,000	65,669,000
Prior year tax positions	288,000	7,406,000	5,086,000
Reduction of prior year tax positions	(1,700,000)	(436,000)	0
Lapse of statute of limitations	(1,605,000)	(24,006,000)	(7,469,000)
Balance, end of period	$ 132,320,000	$ 122,056,000	$ 116,085,000