STOCK-BASED COMPENSATION: Performance Stock Option Unit Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised (in dollars per share)	$ 11.22
Number of shares
Outstanding at beginning of the period (in shares)	2,456,184
Forfeited or cancelled (in shares)	(25,591)
Outstanding at end of the period (in shares)	1,560,140
Exercisable at the end of the period (in shares)	1,378,721
Weighted-average exercise price per share
Outstanding at the beginning of the period (in dollars per share)	$ 13.30
Forfeited or cancelled (in dollars per share)	18.64
Outstanding at the end of the period (in dollars per share)	14.37
Exercisable at the end of the period (in dollars per share)	$ 15.27
Weighted-average remaining contractual term
Weighted average remaining contractual term	4 years 9 months 18 days
Exercisable at the end of the period	4 years 6 months
Aggregate intrinsic value
Outstanding at the end of the period	$ 37,850
Exercisable at the end of the period	32,210
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	34,600	$ 21,600
Performance stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	200	$ 900
Future expense for performance stock option units	$ 600
Period for recognition of unrecognized stock-based compensation expense	3 years
Number of shares
Outstanding at beginning of the period (in shares)	322,823
Forfeited or cancelled (in shares)	(187,885)
Outstanding at end of the period (in shares)	134,938
Exercisable at the end of the period (in shares)	0
Weighted-average exercise price per share
Outstanding at the beginning of the period (in dollars per share)	$ 21.42
Forfeited or cancelled (in dollars per share)	21.41
Outstanding at the end of the period (in dollars per share)	21.44
Exercisable at the end of the period (in dollars per share)	$ 0
Weighted-average remaining contractual term
Weighted average remaining contractual term	1 year 4 months 24 days
Exercisable at the end of the period	0 years
Aggregate intrinsic value
Outstanding at the end of the period	$ 2,320
Exercisable at the end of the period	$ 0
Performance stock | Shares Vesting Based On Relevant Performance Period At March 31 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units reached maturity	161,412
Vesting percentage	0.00%