STOCK PLANS AND STOCK-BASED COMPENSATION Stock Option Activity (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, March 31, 2017 (shares)	1,417,531
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, March 31, 2016 (shares)	1,461,000
Options granted (shares)	251,000
Options exercised (shares)	(295,000)
Options forfeited or expired (shares)	0
Options outstanding, March 31, 2017 (shares)	1,417,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted average exercise price of options outstanding at March 31, 2016 (in dollars per share) | $ / shares	$ 41.24
Weighted average exercise price of options granted (in dollars per share) | $ / shares	44.00
Weighted average exercise price of options exercised (in dollars per share) | $ / shares	33.20
Weighted average exercise price of options forfeited or expired (in dollars per share) | $ / shares	0.00
Weighted average exercise price of options outstanding at March 31, 2017 (in dollars per share) | $ / shares	$ 43.41
Weighted average remaining contractual life of options outstanding at March 31, 2016 (in years)	4 years
Aggregate intrinsic value of options outstanding at March 31, 2017 | $	$ 15,209
Vested or expected to vest at March 31, 2017 (in shares)	1,393,000
Weighted average exercise price of options vested or expected to vest at March 31, 2017 (in dollars per share) | $ / shares	$ 43.35
Weighted average remaining contractual life of options vested or expected to vest at March 31, 2017 (in years)	3 years 329 days
Aggregate intrinsic value of options vested or expected to vest at March 31, 2017 | $	$ 15,030
Exercisable at March 31, 2017 (in shares)	1,007,000
Weighted average exercise price of options exercisable at March 31, 2017 (in dollars per share) | $ / shares	$ 41.80
Weighted average remaining contractual life of options exercisable at March 31, 2017 (in years)	3 years 73 days
Aggregate intrinsic value of options exercisable at March 31, 2017 | $	$ 12,415