Related Person Transactions	9 Months Ended
Sep. 30, 2017
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, 2017, we owned 4,235,000 of Five Star’s common shares, or approximately 8.5% of Five Star’s outstanding common shares. Five Star is our largest tenant and the manager of our managed senior living communities. As of September 30, 2017, our Managing Trustees, the controlling shareholders of RMR LLC's parent, beneficially owned, directly and indirectly, 36.7% of Five Star's outstanding common shares. RMR LLC provides management services to both us and Five Star. See Note 10 for further information regarding our relationships, agreements and transactions with Five Star and Note 4 for further information regarding our investment in Five Star. Our Manager, RMR LLC. See Note 11 for further information regarding our management agreements with RMR LLC. We have historically granted share awards to certain RMR LLC employees under our equity compensation plans. In September 2017 and 2016, we granted annual share awards of 88,100 and 79,650 of our common shares, respectively, to our officers and certain other employees of RMR LLC. In September 2017 and 2016, we purchased 16,654 and 17,667 of our common shares, respectively, at the closing price of our common shares on the Nasdaq on the date of purchase, from certain employees of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. We include the amounts recognized as expense for share awards to RMR LLC employees in general and administrative expenses in our condensed consolidated statements of comprehensive income. RMR Inc. RMR LLC is a subsidiary of RMR Inc. and RMR Inc. is the managing member of RMR LLC. The controlling shareholder of RMR Inc., ABP Trust, is owned by our Managing Trustees. As of September 30, 2017, we owned 2,637,408 shares of class A common stock of RMR Inc. See Note 4 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, an Indiana insurance company, 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) currently expect to pay aggregate annual premiums, including taxes and fees, of approximately $2,433 in connection with this insurance program for the policy year ending June 30, 2018, which amount 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, 2017 and December 31, 2016, our investment in AIC had a carrying value of $7,945 and $7,116, respectively. These amounts are included in other assets in our condensed consolidated balance sheets. We recognized income related to our investment in AIC, which amounts are 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 (losses) on securities which are owned and held for sale by AIC. For further information about these and certain other related person relationships and transactions, please 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, 2017, we owned 4,235,000 of Five Star’s common shares, or approximately 8.5% of Five Star’s outstanding common shares. Five Star is our largest tenant and the manager of our managed senior living communities. As of September 30, 2017, our Managing Trustees, the controlling shareholders of RMR LLC's parent, beneficially owned, directly and indirectly, 36.7% of Five Star's outstanding common shares. RMR LLC provides management services to both us and Five Star. See Note 10 for further information regarding our relationships, agreements and transactions with Five Star and Note 4 for further information regarding our investment in Five Star.

Our Manager, RMR LLC. See Note 11 for further information regarding our management agreements with RMR LLC.

We have historically granted share awards to certain RMR LLC employees under our equity compensation plans. In September 2017 and 2016, we granted annual share awards of 88,100 and 79,650 of our common shares, respectively, to our officers and certain other employees of RMR LLC. In September 2017 and 2016, we purchased 16,654 and 17,667 of our common shares, respectively, at the closing price of our common shares on the Nasdaq on the date of purchase, from certain employees of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. We include the amounts recognized as expense for share awards to RMR LLC employees in general and administrative expenses in our condensed consolidated statements of comprehensive income.

RMR Inc. RMR LLC is a subsidiary of RMR Inc. and RMR Inc. is the managing member of RMR LLC. The controlling shareholder of RMR Inc., ABP Trust, is owned by our Managing Trustees. As of September 30, 2017, we owned 2,637,408 shares of class A common stock of RMR Inc. See Note 4 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, an Indiana insurance company, 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) currently expect to pay aggregate annual premiums, including taxes and fees, of approximately $2,433 in connection with this insurance program for the policy year ending June 30, 2018, which amount 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, 2017 and December 31, 2016, our investment in AIC had a carrying value of $7,945 and $7,116, respectively. These amounts are included in other assets in our condensed consolidated balance sheets. We recognized income related to our investment in AIC, which amounts are 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 (losses) on securities which are owned and held for sale by AIC.

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