FAIR VALUE MEASUREMENT OF ASSETS AND LIABILITIES - Fair Value Hierarchy (Details) - Recurring Basis - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
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	$ 7,196	$ 7,062
Level 2 | Money market funds and time deposits (Note 2)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	452,622	1,066,841
Level 2 | Foreign exchange forward contracts (Note 9)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	43,334	22,022
Total Liabilities	(25,311)	(11,742)
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	67,532	52,680
Level 3 | Contingent consideration in connection with business acquisitions
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Liabilities		(22,426)
Total | Money market funds and time deposits (Note 2)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	452,622	1,066,841
Total | Foreign exchange forward contracts (Note 9)
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Assets	43,334	22,022
Total Liabilities	(25,311)	(11,742)
Total | 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	$ 74,728	59,742
Total | Contingent consideration in connection with business acquisitions
Financial Instruments Measured at Fair Value on a Recurring Basis and Nonrecurring Basis
Total Liabilities		$ (22,426)