Basis of Presentation (Policies)	3 Months Ended
Basis of Presentation (Policies)	Dec. 31, 2025
Accounting Policies [Abstract]
Basis of Presentation	The accompanying condensed consolidated financial statements are unaudited. Certain information and disclosures required by U.S. generally accepted accounting principles, or GAAP, for complete financial statements have been condensed or omitted. We believe the disclosures made are adequate to make the information presented not misleading. However, the accompanying condensed consolidated financial statements should be read in conjunction with the financial statements and notes contained in our Annual Report on Form 10-K for the fiscal year ended September 30, 2025, or our 2025 Annual Report. In the opinion of management, all adjustments considered necessary for a fair statement of results for the interim period have been included. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated. Our operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. We report our results in a single reportable segment, which reflects how our chief operating decision maker, or the CODM, allocates resources and evaluates our financial results. Preparation of these condensed consolidated financial statements in conformity with GAAP requires our management to make certain estimates and assumptions that may affect the amounts reported in these condensed consolidated financial statements and related notes. Significant estimates in the accompanying condensed consolidated financial statements include purchase price allocations, useful lives of intangibles and the fair value of certain assets and liabilities. The actual results could differ from these estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Income Taxes. On December 14, 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740): Improvements to Income Tax Disclosures, or ASU No. 2023-09, which requires public entities to enhance its annual income tax disclosures by requiring: i) consistent categories and greater disaggregation of information in the rate reconciliation, and ii) income taxes paid disaggregated by jurisdiction. The implementation of this ASU will not have a material impact on our consolidated financial statements and we will apply the requirements of ASU No. 2023-09 for our fiscal year ending September 30, 2026. Comprehensive Income. In November 2024, the FASB issued ASU No. 2024-03, Income Statement - Reporting Comprehensive Income - Expense Disaggregation Disclosures (Subtopic 220-40): Disaggregation of Income Statements Expenses, which requires public entities to disclose specific expense categories such as employee compensation, depreciation and intangible asset amortization. These details must be presented in a tabular format in the notes to financial statements for both interim and annual reporting periods. ASU No. 2024-03 is required to be applied prospectively but can be applied retrospectively, and is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods within annual reporting periods beginning after December 15, 2027, with early adoption permitted. We are currently evaluating the impact that ASU No. 2024-03 will have on our consolidated financial statements. Derivatives and Hedging. In September 2025, the FASB issued ASU No. 2025-07, Derivatives and Hedging (Topic 815) and Revenue from Contracts with Customers (Topic 606), which clarifies the application of derivative accounting to certain contracts and updates the guidance for share-based noncash consideration received from a customer in exchange for goods and services. Specifically, this ASU stipulates that entities should apply the guidance in Topic 606 to contracts with share-based noncash consideration from a customer unless and until the entity’s right to receive or retain the share-based noncash consideration is unconditional. ASU No. 2025-07 is effective for annual reporting periods beginning after December 15, 2026 and interim reporting periods within those annual reporting periods, with early adoption permitted. We are currently evaluating the impact that ASU No. 2025-07 will have on our consolidated financial statements. Internal Use Software. In September 2025, the FASB issued ASU No. 2025-06, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40): Targeted Improvements to the Accounting for Internal-Use Software, which requires companies to start capitalizing eligible software costs when management has authorized and committed to funding the software project, and it is probable that the project will be completed and the software will be used to perform the function intended. ASU No. 2025-06 is effective for annual reporting periods beginning after December 15, 2027, and interim reporting periods within those annual reporting periods, with early adoption permitted. We are currently evaluating the impact that ASU No. 2025-06 will have on our consolidated financial statements. Derivatives and Hedging. In November 2025, the FASB issued ASU No. 2025-09, Derivatives and Hedging (Topic 815), which expands the hedged risks permitted to be aggregated in a group of individual forecasted transactions in a cash flow hedge, provides a model to facilitate the application of cash flow hedge accounting to forecasted interest payments on variable rate debt instruments and expands hedge accounting for forecasted purchases and sales of nonfinancial assets, among other improvements. ASU No. 2025-09 is effective for the annual reporting periods beginning after December 15, 2026 and interim reporting periods within those annual reporting periods, with early adoption permitted. We are currently evaluating the impact that ASU No. 2025-09 will have on our consolidated financial statements. Interim Reporting. In December 2025, the FASB issued ASU No. 2025-11, Interim Reporting (Topic 270): Narrow-Scope Improvements, which clarifies the guidance in Topic 270 to improve the consistency of interim financial reporting. The ASU provides a comprehensive list of required interim disclosures and introduces a disclosure principle requiring entities to disclose events since the end of the last annual reporting period that have a material impact on the entity. ASU No. 2025-11 is effective for annual reporting periods beginning after December 15, 2027, and interim reporting periods within those annual reporting periods, with early adoption permitted. We are currently evaluating the impact that ASU No. 2025-11 will have on our consolidated financial statements.

RMR GROUP INC. 10-Q