SUMMARY OF ACCOUNTING POLICIES - Goodwill (Details)	12 Months Ended
Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)
Goodwill [Line Items]
Investment impairments and dispositions	$ 97,691,000	$ 193,063,000	$ 21,895,000
Number of reportable units \| segment	4
Number of operating segments \| segment	4
Impairment charges	$ 0
Activity in goodwill account
Balance, beginning of the period	1,073,055,000
Balance, end of the period	$ 1,064,553,000	1,073,055,000
IEI
Goodwill [Line Items]
Fair value above carrying value (as a percentage)	108.00%
CTG
Goodwill [Line Items]
Fair value above carrying value (as a percentage)	17.00%
Operating segments
Activity in goodwill account
Balance, beginning of the period	$ 1,073,055,000	1,121,170,000
Additions		10,984,000
Divestitures	(1,239,000)	(20,628,000)
Foreign currency translation adjustments	(7,263,000)	(38,471,000)
Balance, end of the period	1,064,553,000	1,073,055,000	1,121,170,000
Operating segments \| HRS
Activity in goodwill account
Balance, beginning of the period	507,209,000	550,983,000
Additions		0
Divestitures	(1,102,000)	(5,303,000)
Foreign currency translation adjustments	(7,263,000)	(38,471,000)
Balance, end of the period	498,844,000	507,209,000	550,983,000
Operating segments \| IEI
Activity in goodwill account
Balance, beginning of the period	333,257,000	337,707,000
Additions		0
Divestitures	(137,000)	(4,450,000)
Foreign currency translation adjustments	0	0
Balance, end of the period	333,120,000	333,257,000	337,707,000
Operating segments \| CEC
Activity in goodwill account
Balance, beginning of the period	129,325,000	124,732,000
Additions		10,984,000
Divestitures	0	(6,391,000)
Foreign currency translation adjustments	0	0
Balance, end of the period	129,325,000	129,325,000	124,732,000
Operating segments \| CTG
Activity in goodwill account
Balance, beginning of the period	103,264,000	107,748,000
Additions		0
Divestitures	0	(4,484,000)
Foreign currency translation adjustments	0	0
Balance, end of the period	103,264,000	$ 103,264,000	$ 107,748,000
Disposed of by Sale \| Wink Labs Inc \| Operating segments \| CTG
Activity in goodwill account
Divestitures	$ (20,600,000)

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of restructuring charges, remediation cost, and asset impairment loss.

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