SHORT-TERM INVESTMENTS (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	$ 448,941	$ 470,736
Gross Unrealized Gain	226	131
Gross Unrealized Loss	(235)	(47)
Fair Value	448,932	470,820
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Rolling Maturity [Abstract]
Due in 1 year or less	362,259
Due in 1-2 years	86,682
Total amortized cost	448,941
Available-for-sale Securities, Debt Maturities, Fair Value, Rolling Maturity [Abstract]
Due in 1 year or less	362,338
Due in 1-2 years	86,594
Total fair value	448,932
Bank time deposits
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	175,745	265,570
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair Value	175,745	265,570
Corporate bonds
Schedule of Available-for-sale Securities [Line Items]
Cost or Amortized Cost	273,196	205,166
Gross Unrealized Gain	226	131
Gross Unrealized Loss	(235)	(47)
Fair Value	$ 273,187	$ 205,250