STOCK PLANS AND STOCK-BASED COMPENSATION (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2014
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 33,265	$ 28,594	$ 23,180
Income tax benefit	(10,950)	(8,451)	(6,790)
Total stock-based compensation expense, net of tax	22,315	20,143	16,390
Cost of revenues
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	3,306	2,583	2,554
Research, development and engineering
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	9,908	8,053	6,404
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	20,051	17,958	14,222
Stock-based compensation expense included in operating expenses
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 29,959	$ 26,011	$ 20,626