EARNINGS 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		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Basic earnings per share:
Net earnings	$ 22,941	$ 1,073	$ 18,305	$ 12,189
Basic weighted-average shares outstanding (in shares)	79,043	77,507	78,983	77,475
Basic earnings (loss) per share (in USD per share)	$ 0.29	$ 0.01	$ 0.23	$ 0.16
Diluted earnings per share:
Basic weighted-average shares outstanding (in shares)	79,043	77,507	78,983	77,475
Dilutive effect of common stock options, warrants, and restricted stock as computed under the treasury stock method (in shares)	2,826	2,344	2,611	2,019
Diluted weighted-average shares outstanding (in shares)	81,869	79,851	81,594	79,494
Diluted earnings (loss) per share (in USD per share)	$ 0.28	$ 0.01	$ 0.22	$ 0.15