FAIR VALUE MEASUREMENT OF ASSETS AND LIABILITIES - Assets and Liabilities Measured at Fair Value (Details) - Recurring Basis - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Money market funds and time deposits
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	$ 424,744	$ 1,066,841
Foreign exchange contracts (Note 8)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	21,003	22,022
Total Liabilities	(25,330)	(11,742)
Contingent consideration
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Liabilities	(1,000)	(22,426)
Deferred compensation plan assets: Mutual funds, money market accounts and equity securities
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	74,715	59,742
Level 1 | Money market funds and time deposits
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	0	0
Level 1 | Foreign exchange contracts (Note 8)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	0	0
Total Liabilities	0	0
Level 1 | Contingent consideration
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Liabilities	0	0
Level 1 | Deferred compensation plan assets: Mutual funds, money market accounts and equity securities
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	7,212	7,062
Level 2 | Money market funds and time deposits
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	424,744	1,066,841
Level 2 | Foreign exchange contracts (Note 8)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	21,003	22,022
Total Liabilities	(25,330)	(11,742)
Level 2 | Contingent consideration
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Liabilities	0	0
Level 2 | Deferred compensation plan assets: Mutual funds, money market accounts and equity securities
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	67,503	52,680
Level 3 | Money market funds and time deposits
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	0	0
Level 3 | Foreign exchange contracts (Note 8)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	0	0
Total Liabilities	0	0
Level 3 | Contingent consideration
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Liabilities	(1,000)	(22,426)
Level 3 | Deferred compensation plan assets: Mutual funds, money market accounts and equity securities
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	$ 0	$ 0