EARNINGS (LOSS) PER SHARE AND STOCKHOLDERS' EQUITY: Reconciliation of basic and diluted earnings (loss) per share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic earnings (loss) per share:
Net earnings (loss)	$ (3,336)	$ 7,140	$ (4,636)	$ 11,116
Basic weighted-average shares outstanding (in shares)	79,235	77,446	78,954	77,459
Basic earnings (loss) per share (in USD per share)	$ (0.04)	$ 0.09	$ (0.06)	$ 0.14
Diluted earnings (loss) per share:
Basic weighted-average shares outstanding (in shares)	79,235	77,446	78,954	77,459
Dilutive effect of common stock options, warrants, and restricted stock as computed under the treasury stock method (in shares)	0	1,831	0	1,858
Diluted weighted-average shares outstanding (in shares)	79,235	79,277	78,954	79,317
Diluted earnings (loss) per share (in USD per share)	$ (0.04)	$ 0.09	$ (0.06)	$ 0.14