COMPUTATION OF EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Numerator:
Net income	$ 22,221	$ 16,288	$ 63,082	$ 55,412
Earnings per common share:
Weighted average common shares-basic	32,242	32,579	32,260	34,723
Dilutive effect of employee equity incentive plans	584	680	635	865
Weighted average common shares-diluted	32,826	33,259	32,895	35,588
Basic earnings per common share (in dollars per share)	$ 0.69	$ 0.50	$ 1.96	$ 1.60
Diluted earnings per common share (in dollars per share)	$ 0.68	$ 0.49	$ 1.92	$ 1.56
Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive	473	353	573	289