DEBT - 1.75 CONVERTIBLE NOTES (Details) - 1.75% Convertible Notes due 2016 $ / shares in Units, label in Thousands		12 Months Ended
	Nov. 16, 2011 USD ($) label $ / shares	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)
Debt Instrument [Line Items]
Interest rate		1.75%
Convertible Debt
Debt Instrument [Line Items]
Interest rate	1.75%	1.75%
Amount pertaining to exercise of over-allotment of debt by underwriters	$ 30,000,000
Initial conversion rate of common stock per $1000 of principal amount of Convertible Notes (in shares)	52.3745
Principal amount used for debt instrument conversion ratio	$ 1,000
Initial conversion price of convertible notes into common stock (in dollars per share) | $ / shares	$ 19.093
Number of shares to be converted into common stock | label	13,094
Estimated fair value of convertible notes	$ 197,373,000
Non-convertible borrowing rate	6.90%
Carrying amount of the equity component of convertible notes	$ 52,627,000
Banking, legal and accounting fees related to issuance of convertible notes	6,875,000
Banking, legal and accounting fees related to issuance of convertible notes allocated to the liability component	5,428,000
Banking, legal and accounting fees related to issuance of convertible notes allocated to the equity component	1,447,000
Principal amount at issuance	$ 250,000,000
The value by which Convertible Notes exceed the principal value		$ 368,430,000	$ 243,251,000