FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
ASSETS:
Cash and cash equivalents	$ 409,632	$ 369,821
Available for sale securities	77,356	77,941
Derivative financial instruments	58	122
Contingent consideration	762
Total assets	487,808	447,884
LIABILITIES:
Contingent purchase consideration		(5,464)
Derivative financial instruments	(68)	(40)
Total liabilities	(68)	(5,504)
U.S. government and municipal obligations
ASSETS:
Available for sale securities	27,622	42,186
Commercial paper
ASSETS:
Available for sale securities	48,722	33,003
Corporate bonds
ASSETS:
Available for sale securities	1,012	2,752
Level 1
ASSETS:
Cash and cash equivalents	409,632	369,821
Derivative financial instruments	0	0
Contingent consideration	0
Total assets	421,376	387,086
LIABILITIES:
Contingent purchase consideration		0
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 \| U.S. government and municipal obligations
ASSETS:
Available for sale securities	10,732	14,513
Level 1 \| Commercial paper
ASSETS:
Available for sale securities	0	0
Level 1 \| Corporate bonds
ASSETS:
Available for sale securities	1,012	2,752
Level 2
ASSETS:
Derivative financial instruments	58	122
Contingent consideration	0
Total assets	65,670	60,798
LIABILITIES:
Contingent purchase consideration		0
Derivative financial instruments	(68)	(40)
Total liabilities	(68)	(40)
Level 2 \| U.S. government and municipal obligations
ASSETS:
Available for sale securities	16,890	27,673
Level 2 \| Commercial paper
ASSETS:
Available for sale securities	48,722	33,003
Level 2 \| Corporate bonds
ASSETS:
Available for sale securities	0	0
Level 3
ASSETS:
Derivative financial instruments	0	0
Contingent consideration	762
Total assets	762	0
LIABILITIES:
Contingent purchase consideration		(5,464)
Derivative financial instruments	0	0
Total liabilities	0	(5,464)
Level 3 \| U.S. government and municipal obligations
ASSETS:
Available for sale securities	0	0
Level 3 \| Commercial paper
ASSETS:
Available for sale securities	0	0
Level 3 \| Corporate bonds
ASSETS:
Available for sale securities	$ 0	$ 0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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