COMPUTATION OF EARNINGS PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income	$ 16,288	$ 30,384	$ 55,412	$ 86,477
Earnings Per Share, Basic and Diluted [Abstract]
Weighted average common shares-basic	32,579	41,901	34,723	41,780
Dilutive effect of employee equity incentive plans	680	799	865	894
Weighted average common shares-diluted	33,259	42,700	35,588	42,674
Basic earnings per common share (in dollars per share)	$ 0.50	$ 0.73	$ 1.60	$ 2.07
Diluted earnings per common share (in dollars per share)	$ 0.49	$ 0.71	$ 1.56	$ 2.03
Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive	353	130	289	442