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INCOME TAXES - Narrative (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Dec. 31, 2025 | Sep. 30, 2025 | Sep. 30, 2024 | Sep. 30, 2023
Income Taxes [Line Items] |  |  |  |
Amount of foreign net operating loss carryforwards |  | $ 88.9 |  |
Equity compensation |  | 5.7 |  |
Accrued interest and penalties related to unrecognized tax benefits |  | 3.4 | $ 0.6 | $ 2.9
Potential increase (decrease) in uncertain tax liabilities |  | 23.9 |  |
Forecast |  |  |  |
Income Taxes [Line Items] |  |  |  |
Potential increase (decrease) in uncertain tax liabilities | $ (6.9) |  |  |
Domestic | Research Tax Credit Carryforward |  |  |  |
Income Taxes [Line Items] |  |  |  |
Amount of net operating loss carryforwards |  | 0.3 |  |
State |  |  |  |
Income Taxes [Line Items] |  |  |  |
Amount of net operating loss carryforwards |  | 18.7 |  |
Foreign |  |  |  |
Income Taxes [Line Items] |  |  |  |
Amount of net operating loss carryforwards |  | 429.6 |  |
Deferred tax assets, net |  | 129.6 |  |
Foreign | Foreign Interest Expense |  |  |  |
Income Taxes [Line Items] |  |  |  |
Amount of net operating loss carryforwards |  | $ 194.4 |  |

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- Definition Amount, after allocation of valuation allowances and deferred tax liability, of deferred tax asset attributable to deductible differences and carryforwards, without jurisdictional netting. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Publisher FASB -URI https://asc.fasb.org/1943274/2147482685/740-10-50-2 + Details
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