v3.26.1
Shareholders’ Equity - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended
Jul. 09, 2026
Jun. 30, 2026
Mar. 31, 2026
Dec. 31, 2025
Jun. 30, 2025
Mar. 31, 2025
Dec. 31, 2024
Jun. 30, 2026
Jun. 30, 2025
Mar. 26, 2026
Sep. 30, 2025
Class of Stock [Line Items]                      
General and administrative   $ 10,668     $ 9,631     $ 31,364 $ 32,161    
Equity based compensation expense   487     $ 454     1,730 $ 1,484    
Cash and cash equivalents   58,203           58,203     $ 62,297
Parent Company                      
Class of Stock [Line Items]                      
Cash and cash equivalents   15,386           15,386     19,478
RMR LLC                      
Class of Stock [Line Items]                      
Cash and cash equivalents   $ 42,817           $ 42,817     $ 42,819
Class A Common Stock                      
Class of Stock [Line Items]                      
Common stock, shares issued (in shares)   16,092,402           16,092,402   6,426,000 16,063,495
Shares issued, price (in usd per share)                   $ 15.56  
General and administrative               $ 600      
Class A Common Stock | 2016 Plan                      
Class of Stock [Line Items]                      
Shares repurchased (in shares)   1,396,000     8,710     6,659 10,381    
Shares repurchased   $ 27     $ 134     $ 108 $ 163    
Common class A and B1                      
Class of Stock [Line Items]                      
Value of dividends   7,692 $ 7,676 $ 7,678 7,595 $ 7,580 $ 7,581 23,046 22,756    
Common class A and B1 | Subsequent Event                      
Class of Stock [Line Items]                      
Dividends declared (in usd per share) $ 0.45                    
Value of dividends $ 7,692                    
Membership Units | RMR LLC                      
Class of Stock [Line Items]                      
Value of dividends   10,270 10,259 10,260 10,201 10,190 10,191 30,789 30,582    
Membership Units | RMR LLC | RMR, Inc                      
Class of Stock [Line Items]                      
Value of dividends   5,470 5,459 5,460 5,401 5,390 5,391 16,389 16,182    
Membership Units | RMR LLC | Abp Trust                      
Class of Stock [Line Items]                      
Value of dividends   $ 4,800 $ 4,800 $ 4,800 $ 4,800 $ 4,800 $ 4,800 $ 14,400 $ 14,400    
Membership Units | Subsequent Event | RMR LLC                      
Class of Stock [Line Items]                      
Shares owned (in shares) 17,092,402,000                    
Membership Units | Subsequent Event | RMR LLC                      
Class of Stock [Line Items]                      
Dividends declared (in usd per share) $ 0.32                    
Value of dividends $ 10,270                    
Membership Units | Subsequent Event | RMR LLC | RMR, Inc                      
Class of Stock [Line Items]                      
Value of dividends 5,470                    
Membership Units | Subsequent Event | RMR LLC | Abp Trust                      
Class of Stock [Line Items]                      
Value of dividends $ 4,800                    
Capital Unit Redeemable Class A Units | Abp Trust                      
Class of Stock [Line Items]                      
Membership units (in shares)   15,000,000           15,000,000