Consolidated Statements of Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Revenues:
Total management, termination, incentive and advisory services revenues	$ 182,703	$ 193,920	$ 236,164
Loan investment interest income	5,848	1,400	0
Compensation and benefits	(3,401)	(87)	0
Income from loan investments, net	2,447	1,313	0
Rental property revenues	8,273	1,604	0
Total reimbursable costs	506,861	700,776	726,152
Total revenues	700,284	897,613	962,316
Expenses:
Compensation and benefits	161,728	170,357	136,355
Equity based compensation	9,664	10,624	12,488
Separation costs	7,078	6,297	2,002
Total compensation and benefits expense	178,470	187,278	150,845
General and administrative	42,497	43,743	36,019
Other reimbursable expenses	422,009	608,688	656,401
Rental property expenses	2,833	462	0
Transaction and acquisition related costs	1,142	7,750	4,221
Depreciation and amortization	11,551	4,713	1,102
Total expenses	658,502	852,634	848,588
Operating income	41,782	44,979	113,728
Interest income	5,197	10,403	10,574
Interest expense	(4,308)	(783)	0
Change in fair value of Earnout liability	8,319	2,589	0
(Loss) gain on investments	(5,085)	7,260	25,237
Gain on sale of real estate	445	0	0
Income before income tax expense	46,350	64,448	149,539
Income tax expense attributable to RMR Inc.	(7,671)	(11,319)	(21,768)
Net income	38,679	53,129	127,771
Net income attributable to noncontrolling interest in The RMR Group LLC	(21,910)	(30,039)	(70,624)
Net loss attributable to other noncontrolling interests	827	40	0
Net income attributable to The RMR Group Inc.	17,596	23,130	57,147
Other comprehensive loss:
Unrealized loss on derivatives	(117)	0	0
Less: unrealized loss on derivatives attributable to noncontrolling interest	55	0	0
Other comprehensive loss attributable to The RMR Group Inc.	(62)	0	0
Comprehensive income attributable to The RMR Group Inc.	$ 17,534	$ 23,130	$ 57,147
Weighted average common shares outstanding - basic (in shares)	16,644	16,532	16,426
Weighted average common shares outstanding - diluted (in shares)	16,644	16,532	16,426
Net income attributable to The RMR Group Inc. per common share - basic (in dollars per share)	$ 1.03	$ 1.38	$ 3.44
Net income attributable to The RMR Group Inc. per common share - diluted (in dollars per share)	$ 1.03	$ 1.38	$ 3.44
Management services
Revenues:
Total management, termination, incentive and advisory services revenues	$ 177,575	$ 188,201	$ 185,702
Termination and incentive fees
Revenues:
Total management, termination, incentive and advisory services revenues	653	1,213	45,942
Advisory services
Revenues:
Total management, termination, incentive and advisory services revenues	4,475	4,506	4,520
Reimbursable compensation and benefits
Revenues:
Total reimbursable costs	77,970	84,169	59,925
Reimbursable equity based compensation
Revenues:
Total reimbursable costs	6,882	7,919	9,826
Other reimbursable expenses
Revenues:
Total reimbursable costs	$ 422,009	$ 608,688	$ 656,401