Indebtedness	9 Months Ended
Sep. 30, 2018
Debt Disclosure [Abstract]
Indebtedness	Note 6. Indebtedness Our principal debt obligations at September 30, 2018 were: (1) $143,000 of outstanding borrowings under our $1,000,000 unsecured revolving credit facility; (2) our $400,000 unsecured term loan; and (3) $3,650,000 aggregate outstanding principal amount of senior unsecured notes. Our revolving credit facility and our term loan are governed by a credit agreement with a syndicate of institutional lenders. We have a $1,000,000 revolving credit facility that is available for general business purposes, including acquisitions. Our revolving credit facility provides that we can borrow, repay and reborrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. On May 10, 2018, we amended and restated the credit agreement governing our revolving credit facility and our term loan. As a result of the amendment, the interest rate payable on borrowings under our revolving credit facility was reduced from a rate of LIBOR plus a premium of 110 basis points per annum to a rate of LIBOR plus a premium of 100 basis points per annum. The facility fee remained unchanged at 20 basis points per annum on the total amount of lending commitments under this facility. The interest rate premium and facility fee are each subject to adjustment based upon changes to our credit ratings. Also as a result of the amendment, the stated maturity date of this facility was extended from July 15, 2018 to July 15, 2022, and, subject to the payment of an extension fee and meeting certain other conditions, we have an option to further extend the maturity date of the facility for two additional six month periods. As a result of this amendment, we recognized a loss on early extinguishment of debt related to the revolving credit facility of $90 during the three months ended June 30, 2018 to write off unamortized debt issuance costs. As of September 30, 2018, the annual interest rate payable on borrowings under our revolving credit facility was 3.09%. The weighted average annual interest rate for borrowings under our revolving credit facility was 2.97% and 3.00% for the three and nine months ended September 30, 2018, respectively, and 2.33% and 2.17% for the three and nine months ended September 30, 2017, respectively. As of September 30, 2018, we had $143,000 outstanding and $857,000 available under our revolving credit facility. As of November 5, 2018, we had $119,000 outstanding and $881,000 available to borrow under our revolving credit facility. As a result of the amendment to our credit agreement, the interest rate payable on borrowings under our term loan was reduced from a rate of LIBOR plus a premium of 120 basis points per annum to a rate of LIBOR plus a premium of 110 basis points per annum, subject to adjustment based upon changes to our credit ratings. Also as a result of the amendment, the stated maturity date of the term loan was extended from April 15, 2019 to July 15, 2023. Our term loan is prepayable without penalty at any time. As a result of this amendment, we recognized a loss on early extinguishment of debt related to the term loan of $70 during the three months ended June 30, 2018 to write off unamortized debt issuance costs. As of September 30, 2018, the annual interest rate for the amount outstanding under our term loan was 3.20%. The weighted average annual interest rate for borrowings under our term loan was 3.19% and 3.02% for the three and nine months ended September 30, 2018, respectively, and 2.43% and 2.20% for the three and nine months ended September 30, 2017, respectively. Our credit agreement also includes a feature under which maximum aggregate borrowings may be increased to up to $2,300,000 on a combined basis in certain circumstances. Our credit agreement and our unsecured senior notes indentures and their supplements provide for acceleration of payment of all amounts outstanding upon the occurrence and continuation of certain events of default, such as, in the case of our credit agreement, a change of control of us, which includes RMR LLC ceasing to act as our business manager. Our credit agreement and our unsecured senior notes indentures and their supplements also contain a number of covenants, including covenants that restrict our ability to incur debts or to make distributions under certain circumstances and generally require us to maintain certain financial ratios. We believe we were in compliance with the terms and conditions of our credit agreement and our unsecured senior notes indentures and their supplements at September 30, 2018. On February 2, 2018, we issued $400,000 principal amount of 4.375% senior notes due 2030 in a public offering. Net proceeds from this offering were $386,400 after discounts and expenses.

Note 6. Indebtedness

Our principal debt obligations at September 30, 2018 were: (1) $143,000 of outstanding borrowings under our $1,000,000 unsecured revolving credit facility; (2) our $400,000 unsecured term loan; and (3) $3,650,000 aggregate outstanding principal amount of senior unsecured notes. Our revolving credit facility and our term loan are governed by a credit agreement with a syndicate of institutional lenders.

We have a $1,000,000 revolving credit facility that is available for general business purposes, including acquisitions. Our revolving credit facility provides that we can borrow, repay and reborrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. On May 10, 2018, we amended and restated the credit agreement governing our revolving credit facility and our term loan. As a result of the amendment, the interest rate payable on borrowings under our revolving credit facility was reduced from a rate of LIBOR plus a premium of 110 basis points per annum to a rate of LIBOR plus a premium of 100 basis points per annum. The facility fee remained unchanged at 20 basis points per annum on the total amount of lending commitments under this facility. The interest rate premium and facility fee are each subject to adjustment based upon changes to our credit ratings. Also as a result of the amendment, the stated maturity date of this facility was extended from July 15, 2018 to July 15, 2022, and, subject to the payment of an extension fee and meeting certain other conditions, we have an option to further extend the maturity date of the facility for two additional six month periods. As a result of this amendment, we recognized a loss on early extinguishment of debt related to the revolving credit facility of $90 during the three months ended June 30, 2018 to write off unamortized debt issuance costs.

As of September 30, 2018, the annual interest rate payable on borrowings under our revolving credit facility was 3.09%. The weighted average annual interest rate for borrowings under our revolving credit facility was 2.97% and 3.00% for the three and nine months ended September 30, 2018, respectively, and 2.33% and 2.17% for the three and nine months ended September 30, 2017, respectively. As of September 30, 2018, we had $143,000 outstanding and $857,000 available under our revolving credit facility. As of November 5, 2018, we had $119,000 outstanding and $881,000 available to borrow under our revolving credit facility.

As a result of the amendment to our credit agreement, the interest rate payable on borrowings under our term loan was reduced from a rate of LIBOR plus a premium of 120 basis points per annum to a rate of LIBOR plus a premium of 110 basis points per annum, subject to adjustment based upon changes to our credit ratings. Also as a result of the amendment, the stated maturity date of the term loan was extended from April 15, 2019 to July 15, 2023. Our term loan is prepayable without penalty at any time. As a result of this amendment, we recognized a loss on early extinguishment of debt related to the term loan of $70 during the three months ended June 30, 2018 to write off unamortized debt issuance costs.

As of September 30, 2018, the annual interest rate for the amount outstanding under our term loan was 3.20%. The weighted average annual interest rate for borrowings under our term loan was 3.19% and 3.02% for the three and nine months ended September 30, 2018, respectively, and 2.43% and 2.20% for the three and nine months ended September 30, 2017, respectively.

Our credit agreement also includes a feature under which maximum aggregate borrowings may be increased to up to $2,300,000 on a combined basis in certain circumstances. Our credit agreement and our unsecured senior notes indentures and their supplements provide for acceleration of payment of all amounts outstanding upon the occurrence and continuation of certain events of default, such as, in the case of our credit agreement, a change of control of us, which includes RMR LLC ceasing to act as our business manager. Our credit agreement and our unsecured senior notes indentures and their supplements also contain a number of covenants, including covenants that restrict our ability to incur debts or to make distributions under certain circumstances and generally require us to maintain certain financial ratios. We believe we were in compliance with the terms and conditions of our credit agreement and our unsecured senior notes indentures and their supplements at September 30, 2018.

On February 2, 2018, we issued $400,000 principal amount of 4.375% senior notes due 2030 in a public offering. Net proceeds from this offering were $386,400 after discounts and expenses.