DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION (Policies)	3 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The Company has prepared the accompanying unaudited interim condensed consolidated financial statements pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) regarding interim financial reporting. Accordingly, they do not include all of the information and footnotes required by generally accepted accounting principles (“GAAP”), and therefore should be read in conjunction with the Company’s audited consolidated financial statements, and the notes thereto, included in the Company’s Annual Report on Form 10-K for the fiscal year ended September 30, 2023. In the opinion of management, the condensed consolidated financial statements for the three months ended December 31, 2023 and 2022 include all adjustments which are necessary for a fair presentation of the results of the interim periods and of the Company’s financial position at December 31, 2023. The results of operations for the three months ended December 31, 2023 are not necessarily indicative of the results for the fiscal year ending September 30, 2024. Certain prior year amounts have been reclassified within the condensed consolidated statements of operations for consistency with the current year presentation. Specifically, depreciation expense has been combined with amortization of intangible assets. These reclassifications had no effect on the reported results of operations. Further, certain financing activities have been reclassified within the condensed consolidated statements of cash flows for consistency with the current year presentation.
Use of Estimates	Use of Estimates The preparation of condensed consolidated financial statements in conformity with GAAP requires the Company to make estimates and judgments that affect the reported amounts of assets, liabilities, revenues, and expenses, and related disclosures of contingent assets and liabilities. These include, but are not limited to, management estimates in the calculation and timing of revenue recognition, pension liabilities, deferred tax assets and liabilities and the related valuation allowance. Although estimates are based upon management’s best estimate using historical experience, current events, and actions, actual results could differ from those estimates. Changes in estimates are reflected in reported results in the period in which they become known.
Consolidation	Consolidation The accompanying condensed consolidated financial statements are unaudited and have been prepared by the Company, including all subsidiaries and prior to December 23, 2023, a variable interest entity (“VIE”) it previously consolidated in accordance with GAAP. The VIE does not materially impact our net assets or net (loss) income. During December 2023, the Company entered into a transition services agreement with Vanguard Supply Chain Solutions ("VSCS"), one of the Company's transportation providers, to enable the in-house integration of Inotiv’s North American transportation operations. Following this transaction, Inotiv was no longer required to consolidate this entity. Subsequent to December 31, 2023, the Company successfully completed the in-house integration of its North American transportation operations. The Company accounts for noncontrolling interests in accordance with Accounting Standards Codification (“ASC”) 810, “Consolidation” (“ASC 810”). ASC 810 requires companies with noncontrolling interests to disclose such interests as a portion of equity but separate from the parent’s equity. The noncontrolling interests’ portion of net loss is presented on the condensed consolidated statements of operations.
Concentration of Risk	Concentration of Risk Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of trade receivables from clients in the biopharmaceutical, contract research, academic, and governmental sectors. The Company believes its exposure to credit risk is minimal, as the majority of the clients are predominantly well established and viable. Additionally, the Company maintains allowances for potential credit losses. The Company’s exposure to credit loss in the event that payment is not received for revenue recognized equals the outstanding trade receivables and contract assets less fees invoiced in advance.