Segment Reporting (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) item	Jun. 30, 2015 USD ($)
Segment Reporting
Number of segment | item			1
Revenues
Management services	$ 41,867	$ 41,156	$ 182,940	$ 122,489
Reimbursable payroll and related costs	9,744	6,427	25,993	20,535
Advisory services	600	596	1,741	1,801
Total revenues	52,211	48,179	210,674	144,825
Expenses
Compensation and benefits	22,719	20,596	65,584	64,155
Separation expense	1,195		1,358	116
General and administrative	6,110	8,970	19,110	18,657
Depreciation expense	349	512	1,333	1,662
Total expenses	30,373	30,078	87,385	84,590
Operating income	21,838	18,101	123,289	60,235
Interest and other income	68	535	144	1,698
Unrealized gains (losses) attributable to changes in fair value of stock		(1,727)		(290)
Income before income tax expense and equity in earnings of investee	21,906	16,909	123,433	61,643
Income tax expense	(4,504)	(651)	(19,904)	(654)
Equity in earnings of investee		15		115
Net income	17,402	16,273	103,529	61,104
Intersegment Eliminations
Revenues
Total revenues	192	297	737	893
RMR LLC
Revenues
Management services	41,867	40,976	182,882	122,249
Reimbursable payroll and related costs	9,744	6,427	25,993	20,535
Total revenues	51,611	47,403	208,875	142,784
Expenses
Compensation and benefits	22,445	20,090	64,712	62,621
Separation expense	1,195		1,358	116
General and administrative	5,778	8,827	18,234	18,287
Depreciation expense	349	512	1,333	1,662
Total expenses	29,767	29,429	85,637	82,686
Operating income	21,844	17,974	123,238	60,098
Interest and other income	62	517	137	1,633
Unrealized gains (losses) attributable to changes in fair value of stock		(1,682)		(317)
Income before income tax expense and equity in earnings of investee	21,906	16,809	123,375	61,414
Income tax expense		3	(1)
Equity in earnings of investee		15		115
Net income	21,906	16,827	123,374	61,529
All other operations
Revenues
Management services		180	58	240
Advisory services	600	596	1,741	1,801
Total revenues	600	776	1,799	2,041
Expenses
Compensation and benefits	274	506	872	1,534
General and administrative	332	143	876	370
Total expenses	606	649	1,748	1,904
Operating income	(6)	127	51	137
Interest and other income	6	18	7	65
Unrealized gains (losses) attributable to changes in fair value of stock		(45)		27
Income before income tax expense and equity in earnings of investee		100	58	229
Income tax expense	(4,504)	(654)	(19,903)	(654)
Net income	$ (4,504)	$ (554)	$ (19,845)	$ (425)