COMMITMENTS AND CONTINGENCIES - Separation Programs (Details) - Involuntary separation program - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 2,535	$ 2,727	$ 4,151	$ 4,446
Direct cost
Restructuring Cost and Reserve [Line Items]
Severance costs	2,525	1,212	3,988	2,713
General and administrative
Restructuring Cost and Reserve [Line Items]
Severance costs	$ 10	$ 1,515	$ 163	$ 1,733

Amount of expenses for special or contractual termination benefits provided to current employees involuntarily terminated under a benefit arrangement associated exit or disposal activities pursuant to an authorized plan. Excludes expenses related to one-time termination benefits, a discontinued operation or an asset retirement obligation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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