REVENUE FROM CONTRACTS WITH CUSTOMERS (Income Statement) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 387,982	$ 418,216
Cost of goods sold	131,365	194,569
Gross profit	256,617	223,647
General and administrative	67,735	60,603
Selling and marketing	58,306	52,214
Research and development	50,712	42,269
Business reorganization	(242)	10,599
Depreciation and amortization	9,260	7,743
Total operating expenses	185,771	173,428
Income from operations	70,846	50,219
Interest and other, net	6,601	(2,808)
Income before income taxes	77,447	47,411
Provision for (benefit from) income taxes	5,754	(12,865)
Net income	$ 71,693	$ 60,276	[1]
Basic earnings (loss) per share (in dollars per share)	$ 0.63	$ 0.57
Diluted earnings (loss) per share (in dollars per share)	$ 0.62	$ 0.56
Amounts without adoption of New Revenue Accounting Standard
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ 401,981
Cost of goods sold	157,089
Gross profit	244,892
General and administrative	67,735
Selling and marketing	58,306
Research and development	50,712
Business reorganization	(242)
Depreciation and amortization	9,260
Total operating expenses	185,771
Income from operations	59,121
Interest and other, net	6,013
Income before income taxes	65,134
Provision for (benefit from) income taxes	(1,970)
Net income	$ 67,104
Basic earnings (loss) per share (in dollars per share)	$ 0.59
Diluted earnings (loss) per share (in dollars per share)	$ 0.58
Increase (decrease) due to adoption of New Revenue Accounting Standard | Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Net revenue	$ (13,999)
Cost of goods sold	(25,724)
Gross profit	11,725
General and administrative	0
Selling and marketing	0
Research and development	0
Business reorganization	0
Depreciation and amortization	0
Total operating expenses	0
Income from operations	11,725
Interest and other, net	588
Income before income taxes	12,313
Provision for (benefit from) income taxes	7,724
Net income	$ 4,589

[1] Prior period amounts have been adjusted retrospectively to reflect the adoption of ASU 2016-08, Statement of Cash Flows (Topic 230): Restricted Cash. Refer to Note 1 for further discussion.