Related Person Transactions	9 Months Ended
Related Person Transactions	Sep. 30, 2022
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions We have relationships and historical and continuing transactions with RMR, The RMR Group Inc., or RMR Inc., AlerisLife (including Five Star) and others related to them, including other companies to which RMR or its subsidiaries provide management services and some of which have trustees, directors or officers who are also our Trustees or officers. RMR Inc. is the managing member of RMR. The Chair of our Board and one of our Managing Trustees, Adam D. Portnoy, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., the chair of the board of directors, a managing director and the president and chief executive officer of RMR Inc., an officer and employee of RMR and the chair of the board of directors and a managing director of AlerisLife. Jennifer F. Francis, our other Managing Trustee and our President and Chief Executive Officer, and our Chief Financial Officer and Treasurer are also employees and officers of RMR. Jennifer B. Clark, our Secretary and former Managing Trustee, also serves as a managing director and the executive vice president, general counsel and secretary of RMR Inc., an officer and employee of RMR, an officer of ABP Trust and a managing director and the secretary of AlerisLife. Certain of AlerisLife's officers are officers and employees of RMR. Some of our Independent Trustees also serve as independent trustees or independent directors of other public companies to which RMR or its subsidiaries provide management services. Adam Portnoy serves as the chair of the board and as a managing director or managing trustee of these companies. Other officers of RMR, including Ms. Clark and certain of our officers, serve as managing trustees, managing directors or officers of certain of these companies. In addition, officers of RMR and RMR Inc. serve as our officers and officers of other companies to which RMR or its subsidiaries provide management services. See Note 7 for information relating to awards of our common shares we made in September 2022 to our officers and certain other employees of RMR and our repurchase of common shares from our officers and certain current and former officers and employees of RMR in satisfaction of tax withholding and payment obligations owed in connection with the vesting of awards of our common shares to them. We include amounts recognized as expense for common share awards to our officers and RMR officers and employees in general and administrative expenses in our condensed consolidated statements of comprehensive income (loss). AlerisLife. We are currently AlerisLife's largest stockholder. As of September 30, 2022, we owned approximately 32.8% of AlerisLife's outstanding common shares. Five Star is an operating division of AlerisLife. Five Star manages certain of the senior living communities we own pursuant to the Master Management Agreement. RMR provides management services to both us and AlerisLife. See Note 9 for further information regarding our relationships, agreements and transactions with AlerisLife (including Five Star) and Note 5 for further information regarding our investment in AlerisLife. As of September 30, 2022, ABP Acquisition LLC, a subsidiary of ABP Trust, the controlling shareholder of RMR Inc., together with ABP Trust, owned approximately 6.2% of AlerisLife's outstanding common shares. Our Joint Ventures. We have two separate joint venture arrangements with two third party institutional investors, the Seaport JV and the LSMD JV. We own a 10% equity interest in the Seaport JV and a 20% equity interest in the LSMD JV; from January 2022 until June 28, 2022, we owned a 20% equity interest in the Seaport JV. We initially entered into the Seaport JV prior to January 1, 2021, and we entered into the LSMD JV in January 2022. RMR provides management services to both of these joint ventures. Our joint ventures are not our consolidated subsidiaries and, as a result, we are not obligated to pay management fees to RMR under our management agreements with RMR for the services it provides regarding the joint ventures. Prior to December 23, 2021, the Seaport JV was our consolidated subsidiary and, as such, we were previously obligated to pay management fees to RMR under our management agreements with RMR for the services it provided regarding that joint venture; however, that joint venture paid management fees directly to RMR, and any such fees paid by that joint venture were credited against the fees payable by us to RMR. In addition, we wholly owned the 10 medical office and life science properties until the contribution of these properties to the applicable joint venture in January 2022 and we paid management fees to RMR for the management services it provided to us for those properties up until that time. As of September 30, 2022, in connection with entering into the LSMD JV in January 2022, we paid mortgage escrow amounts and closing costs of $9,558 that were payable by that joint venture. Those costs are presented as other assets, net, in our condensed consolidated balance sheet. Our Manager, RMR. We have two agreements with RMR to provide management services to us. See Note 10 for further information regarding our management agreements with RMR. For further information about these and other such relationships and certain other related person transactions, see our Annual Report.