CONDENSED CONSOLIDATED STATEMENT OF EQUITY - 6 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in Capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury Stock
Balance, beginning of the period (in shares) at Mar. 31, 2018		136,079,676				(58,304,917)
Balance, beginning of the period at Mar. 31, 2018	$ 749,095	$ 13,609	$ 1,235,679	$ 628,331	$ 10,767	$ (1,139,291)
Increase (Decrease) in Stockholders' Equity
Employee stock awards, benefit plans and other issuances (in shares)		439,337				(496,055)
Employee stock awards, benefit plans and other issuances	(6,503)	$ 44	8,077			$ (14,624)
Non-cash stock-based compensation (in shares)		240,584
Non-cash stock-based compensation	34,092	$ 24	34,068
Restricted stock units vested (in shares)		1,596,551
Restricted stock units vested	0	$ 159	(159)
Warrant exercises	0		(51)			$ 51
Warrant exercises (in shares)						3,488
Acquisition of treasury stock (in shares)						1,853,071
Acquisition of treasury stock	(45,766)					$ (45,766)
Other comprehensive income (loss):
Foreign currency translation	(575)				(575)
Net earnings (loss)	17,608			17,608
Balance, end of the period (in shares) at Sep. 30, 2018		138,356,148				(60,650,555)
Balance, end of the period at Sep. 30, 2018	$ 760,678	$ 13,836	$ 1,277,614	$ 658,666	$ 10,192	$ (1,199,630)