SUPPLEMENTARY FINANCIAL INFORMATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2016
Valuation allowance for deferred income taxes
Movement in valuation and qualifying accounts
Beginning Balance	$ 184,085	$ 170,574	$ 133,468
Additions	11,555	13,511	37,106
Deductions	0	0	0
Other	0	0	0
Ending Balance	195,640	184,085	170,574
Price protection, sales returns and other allowances
Movement in valuation and qualifying accounts
Beginning Balance	65,114	45,153	69,305
Additions	59,674	127,744	64,498
Deductions	(74,936)	(100,934)	(86,622)
Other	3,191	(6,849)	(2,028)
Ending Balance	53,043	65,114	45,153
Price protection
Movement in valuation and qualifying accounts
Additions	27,088	65,336	36,546
Other sales allowances
Movement in valuation and qualifying accounts
Additions	31,428	45,850	23,073
Returns
Movement in valuation and qualifying accounts
Additions	1,158	16,558	4,879
Allowance for doubtful accounts
Movement in valuation and qualifying accounts
Beginning Balance	1,369	399	1,166
Additions	0	974	0
Deductions	(122)	(4)	(767)
Other	0	0	0
Ending Balance	1,247	1,369	399
Total accounts receivable allowances
Movement in valuation and qualifying accounts
Beginning Balance	66,483	45,552	70,471
Additions	59,674	128,718	64,498
Deductions	(75,058)	(100,938)	(87,389)
Other	3,191	(6,849)	(2,028)
Ending Balance	$ 54,290	$ 66,483	$ 45,552