STOCK-BASED COMPENSATION - Stock Option Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Stock Option Rollforward
Stock options outstanding at the beginning of the period (in shares)	3,998	4,462
Options granted (in shares)	222	427
Options exercised (in shares)	(641)	(421)
Options canceled and forfeited (in shares)	(192)	(176)
Stock options outstanding at the end of the period (in shares)	3,387	4,292
Weighted-average fair value of grants during the period (in dollars per share)	$ 8.27	$ 5.30
Total intrinsic value of options exercised during the period	$ 9,148	$ 4,312
Weighted-average remaining recognition period at period-end (in years)	2 years 6 months 10 days	2 years 1 month 20 days
Stock Award Rollforward
Stock awards outstanding at the beginning of the period: (in shares)	5,939	4,950
Stock awards granted (in shares)	4,993	2,884
Stock awards vested (in shares)	(2,123)	(1,615)
Stock awards canceled and forfeited (in shares)	(700)	(447)
Stock awards outstanding at the end of the period: (in shares)	8,109	5,772
Weighted-average fair value of grants during the period (in dollars per share)	$ 20.05	$ 13.89
Weighted-average remaining recognition period at period-end (in years)	2 years 5 months 12 days	2 years 8 months 2 days
Total unrecognized compensation expense at period-end	$ 112,970	$ 64,625