| DESCRIPTION OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill and Purchased Intangible Assets (Details) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
| Mar. 31, 2020 | Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2018 | |
| Goodwill | ||||
| Goodwill impairment | $ 256,649 | $ 0 | $ 0 | |
| Specialty Semiconductor Process | ||||
| Goodwill | ||||
| Goodwill impairment | $ 144,200 | 144,179 | ||
| PCB and Display | ||||
| Goodwill | ||||
| Goodwill impairment | $ 112,500 | $ 112,470 | ||
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- Definition Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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| X | ||||||||||
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- Details 
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- Details 
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