FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015
ASSETS:
Cash and cash equivalents	$ 210,711	$ 104,893
Marketable securities	141,364	159,964
Derivative financial instruments	191	15
Contingently returnable consideration	16,131
Total assets	368,397	264,872
LIABILITIES:
Contingent consideration	(7,293)	(4,484)
Derivative financial instruments	(158)	(1,664)
Total liabilities	(7,451)	(6,148)
U.S. government and municipal obligations
ASSETS:
Marketable securities	123,328	145,345
Commercial paper
ASSETS:
Marketable securities	16,172	5,095
Corporate bonds
ASSETS:
Marketable securities	1,864	9,524
Level 1
ASSETS:
Cash and cash equivalents	210,711	104,893
Derivative financial instruments	0	0
Contingently returnable consideration	0
Total assets	253,691	160,981
LIABILITIES:
Contingent consideration	0	0
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Marketable securities	41,116	46,564
Level 1 | Commercial paper
ASSETS:
Marketable securities	0	0
Level 1 | Corporate bonds
ASSETS:
Marketable securities	1,864	9,524
Level 2
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	$ 191	15
Contingently returnable consideration
Total assets	$ 98,575	103,891
LIABILITIES:
Contingent consideration	0	0
Derivative financial instruments	(158)	(1,664)
Total liabilities	(158)	(1,664)
Level 2 | U.S. government and municipal obligations
ASSETS:
Marketable securities	82,212	98,781
Level 2 | Commercial paper
ASSETS:
Marketable securities	16,172	5,095
Level 2 | Corporate bonds
ASSETS:
Marketable securities	0	0
Level 3
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	0	0
Contingently returnable consideration	16,131
Total assets	16,131	0
LIABILITIES:
Contingent consideration	(7,293)	(4,484)
Derivative financial instruments	0	0
Total liabilities	(7,293)	(4,484)
Level 3 | U.S. government and municipal obligations
ASSETS:
Marketable securities	0	0
Level 3 | Commercial paper
ASSETS:
Marketable securities	0	0
Level 3 | Corporate bonds
ASSETS:
Marketable securities	$ 0	$ 0