Related Person Transactions	9 Months Ended
Sep. 30, 2018
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions We have relationships and historical and continuing transactions with Five Star, RMR LLC, RMR Inc., Affiliates Insurance Company, or AIC, and others related to them, including other companies to which RMR LLC provides management services and which have trustees, directors and officers who are also our Trustees or officers. Five Star. We are currently one of Five Star’s largest stockholders. As of September 30, 2018, we owned 4,235,000 of Five Star’s common shares, or approximately 8.4% of Five Star’s outstanding common shares. Five Star is our largest tenant and the manager of our managed senior living communities. RMR LLC provides management services to both us and Five Star. As of September 30, 2018, a subsidiary of ABP Trust, the controlling shareholder of RMR Inc., owned 35.6% of Five Star's outstanding common shares. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee of ABP Trust and a managing director of Five Star. See Note 9 for further information regarding our relationships, agreements and transactions with Five Star and Note 5 for further information regarding our investment in Five Star. Our Manager, RMR LLC. We have two agreements with RMR LLC to provide management services to us. See Note 10 for further information regarding our management agreements with RMR LLC. We have historically granted share awards to our officers and other employees of RMR LLC under our equity compensation plans. In September 2018 and 2017, we granted annual awards of 105,800 and 88,100 of our common shares, respectively, to our officers and other employees of RMR LLC. In September 2018 and 2017, we purchased 18,121 and 16,654 of our common shares, respectively, valued at the closing price of our common shares on Nasdaq on the applicable date of purchase, in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares to certain employees of RMR LLC. We include the amounts recognized as expense for share awards to our officers and other RMR LLC employees in general and administrative expenses in our condensed consolidated statements of comprehensive income. RMR Inc. RMR LLC is a majority owned subsidiary of RMR Inc. and RMR Inc. is the managing member of RMR LLC. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., a managing director, president and chief executive officer of RMR Inc., and an officer of RMR LLC. Jennifer B. Clark, our other Managing Trustee, also serves as a managing director and as executive vice president, general counsel and secretary of RMR Inc. and an officer of ABP Trust and RMR LLC. Other officers of RMR LLC also serve as our officers. As of September 30, 2018, we owned 2,637,408 shares of class A common stock of RMR Inc. See Note 5 for further information regarding our investment in RMR Inc. AIC. We, ABP Trust, Five Star and four other companies to which RMR LLC provides management services currently own AIC in equal amounts. We and the other AIC shareholders participate in a combined property insurance program arranged and reinsured in part by AIC; we also have a one year standalone insurance policy that provides coverage for our MOB (two buildings) located in Boston, Massachusetts that is owned in our joint venture arrangement, which we obtained as a part of this insurance program. We (including our consolidated joint venture) paid aggregate annual premiums, including taxes and fees, of approximately $4,413 in connection with the renewal of this insurance program for the policy year ending June 30, 2019. The amount of premiums may be adjusted from time to time as we acquire and dispose of properties that are included in this insurance program. As of September 30, 2018 and December 31, 2017, our investment in AIC had a carrying value of $9,157 and $8,185, respectively. These amounts are included in other assets in our condensed consolidated balance sheets. We recognized income related to our investment in AIC, which is presented as equity in earnings of an investee in our condensed consolidated statements of comprehensive income. Our other comprehensive income includes our proportionate part of unrealized gains on securities that are owned by AIC related to our investment in AIC. For further information about these and other such relationships and certain other related person transactions, refer to our Annual Report.

Related Person Transactions

We have relationships and historical and continuing transactions with Five Star, RMR LLC, RMR Inc., Affiliates Insurance Company, or AIC, and others related to them, including other companies to which RMR LLC provides management services and which have trustees, directors and officers who are also our Trustees or officers.

Five Star. We are currently one of Five Star’s largest stockholders. As of September 30, 2018, we owned 4,235,000 of Five Star’s common shares, or approximately 8.4% of Five Star’s outstanding common shares. Five Star is our largest tenant and the manager of our managed senior living communities. RMR LLC provides management services to both us and Five Star. As of September 30, 2018, a subsidiary of ABP Trust, the controlling shareholder of RMR Inc., owned 35.6% of Five Star's outstanding common shares. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee of ABP Trust and a managing director of Five Star. See Note 9 for further information regarding our relationships, agreements and transactions with Five Star and Note 5 for further information regarding our investment in Five Star.

Our Manager, RMR LLC. We have two agreements with RMR LLC to provide management services to us. See Note 10 for further information regarding our management agreements with RMR LLC.

We have historically granted share awards to our officers and other employees of RMR LLC under our equity compensation plans. In September 2018 and 2017, we granted annual awards of 105,800 and 88,100 of our common shares, respectively, to our officers and other employees of RMR LLC. In September 2018 and 2017, we purchased 18,121 and 16,654 of our common shares, respectively, valued at the closing price of our common shares on Nasdaq on the applicable date of purchase, in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares to certain employees of RMR LLC. We include the amounts recognized as expense for share awards to our officers and other RMR LLC employees in general and administrative expenses in our condensed consolidated statements of comprehensive income.

RMR Inc. RMR LLC is a majority owned subsidiary of RMR Inc. and RMR Inc. is the managing member of RMR LLC. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., a managing director, president and chief executive officer of RMR Inc., and an officer of RMR LLC. Jennifer B. Clark, our other Managing Trustee, also serves as a managing director and as executive vice president, general counsel and secretary of RMR Inc. and an officer of ABP Trust and RMR LLC. Other officers of RMR LLC also serve as our officers. As of September 30, 2018, we owned 2,637,408 shares of class A common stock of RMR Inc. See Note 5 for further information regarding our investment in RMR Inc.

AIC. We, ABP Trust, Five Star and four other companies to which RMR LLC provides management services currently own AIC in equal amounts. We and the other AIC shareholders participate in a combined property insurance program arranged and reinsured in part by AIC; we also have a one year standalone insurance policy that provides coverage for our MOB (two buildings) located in Boston, Massachusetts that is owned in our joint venture arrangement, which we obtained as a part of this insurance program. We (including our consolidated joint venture) paid aggregate annual premiums, including taxes and fees, of approximately $4,413 in connection with the renewal of this insurance program for the policy year ending June 30, 2019. The amount of premiums may be adjusted from time to time as we acquire and dispose of properties that are included in this insurance program.

As of September 30, 2018 and December 31, 2017, our investment in AIC had a carrying value of $9,157 and $8,185, respectively. These amounts are included in other assets in our condensed consolidated balance sheets. We recognized income related to our investment in AIC, which is presented as equity in earnings of an investee in our condensed consolidated statements of comprehensive income. Our other comprehensive income includes our proportionate part of unrealized gains on securities that are owned by AIC related to our investment in AIC.

For further information about these and other such relationships and certain other related person transactions, refer to our Annual Report.