COMPUTATION OF EARNINGS (LOSS) PER COMMON SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Basic earnings per common share:
Net income	$ 14,471	$ 18,828
Income allocated to participating securities, basic	(325)
Net income attributable to common shareholders, basic	$ 14,146	$ 18,828
Weighted average common shares, basic (in shares)	32,594	32,506
Basic earnings per common share (in dollars per share)	$ 0.43	$ 0.58
Diluted earnings per common share:
Net effect of reallocating undistributed earnings of unvested shareholders	$ 6
Net income attributable to common shareholders, diluted	$ 14,152	$ 18,828
Dilutive effect of employee equity incentive plans (in shares)	940	705
Weighted average common shares-diluted (in shares)	33,534	33,211
Diluted earnings (loss) per common share (in dollars per share)	$ 0.42	$ 0.57
Potentially dilutive securities excluded from diluted earnings per common share because their effect is anti-dilutive	202	457
Pro Forma [Member]
Basic earnings per common share:
Basic earnings per common share (in dollars per share)		$ 0.56
Diluted earnings per common share:
Diluted earnings (loss) per common share (in dollars per share)		$ 0.55