FAIR VALUE MEASUREMENTS - Schedule of Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017
ASSETS:
Cash and cash equivalents	$ 261,736	$ 304,880
Fair Value	147,914	159,825
Derivative financial instruments	420	110
Total assets	410,070	464,815
LIABILITIES:
Contingent purchase consideration	(5,487)	(5,449)
Derivative financial instruments	(17)	(213)
Total liabilities	(5,504)	(5,662)
U.S. government and municipal obligations
ASSETS:
Fair Value	111,984	120,901
Commercial paper
ASSETS:
Fair Value	32,672	29,469
Corporate bonds
ASSETS:
Fair Value	3,258	7,956
Certificate of deposits
ASSETS:
Fair Value		1,499
Level 1
ASSETS:
Cash and cash equivalents	261,736	304,880
Derivative financial instruments	0	0
Total assets	300,691	353,464
LIABILITIES:
Contingent purchase consideration	0	0
Derivative financial instruments	0	0
Total liabilities	0	0
Level 1 | U.S. government and municipal obligations
ASSETS:
Fair Value	35,697	40,628
Level 1 | Commercial paper
ASSETS:
Fair Value	0	0
Level 1 | Corporate bonds
ASSETS:
Fair Value	3,258	7,956
Level 1 | Certificate of deposits
ASSETS:
Fair Value		0
Level 2
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	420	110
Total assets	109,379	111,351
LIABILITIES:
Contingent purchase consideration	0	0
Derivative financial instruments	(17)	(213)
Total liabilities	(17)	(213)
Level 2 | U.S. government and municipal obligations
ASSETS:
Fair Value	76,287	80,273
Level 2 | Commercial paper
ASSETS:
Fair Value	32,672	29,469
Level 2 | Corporate bonds
ASSETS:
Fair Value	0	0
Level 2 | Certificate of deposits
ASSETS:
Fair Value		1,499
Level 3
ASSETS:
Cash and cash equivalents	0	0
Derivative financial instruments	0	0
Total assets	0	0
LIABILITIES:
Contingent purchase consideration	(5,487)	(5,449)
Derivative financial instruments	0	0
Total liabilities	(5,487)	(5,449)
Level 3 | U.S. government and municipal obligations
ASSETS:
Fair Value	0	0
Level 3 | Commercial paper
ASSETS:
Fair Value	0	0
Level 3 | Corporate bonds
ASSETS:
Fair Value	$ 0	0
Level 3 | Certificate of deposits
ASSETS:
Fair Value		$ 0