SHARE-BASED COMPENSATION: (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Stock Option Activity - Number of Shares
Outstanding at beginning of the period (in shares)	3,604,102
Exercised (in shares)	(158,632)
Forfeited or cancelled (in shares)	(28,441)
Outstanding at end of the period (in shares)	3,417,029
Exercisable at the end of the period (in shares)	2,645,523
Weighted-average exercise price per share
Outstanding at the beginning of the period (in dollars per share)	$ 14.52
Exercised (in dollars per share)	9.00
Forfeited or cancelled (in dollars per share)	13.42
Outstanding at the end of the period (in dollars per share)	14.78
Exercisable at the end of the period (in dollars per share)	$ 15.03
Weighted-average remaining contractual term
Outstanding at the end of the period	5 years 1 month 6 days
Exercisable at the end of the period	4 years 3 months 18 days
Aggregate intrinsic value
Exercised	$ 1,997
Outstanding at the end of the period	25,363
Exercisable at the end of the period	$ 19,033
Performance Stock Option Unit
Share-based compensation
Period for recognition of unrecognized stock-based compensation expense	4 years
Stock Option and Equity Compensation Plans
Share-based compensation
Total shares reserved for issuance since inception of the stock option and equity compensation plans (in shares)	28,900,000
Shares which remained available for future grants (in shares)	2,300,000
Stock options
Share-based compensation
Share-based compensation expense	$ 1,800	$ 2,700
Future share-based compensation expense	$ 7,800
Period for recognition of unrecognized stock-based compensation expense	4 years
Stock Appreciation Rights (SARs)
Weighted-average remaining contractual term
Exercisable at the end of the period	0 years