Indebtedness	9 Months Ended
Sep. 30, 2016
Debt Disclosure [Abstract]
Indebtedness	Indebtedness Our principal debt obligations at September 30, 2016 were: (1) $150,000 of outstanding borrowings under our $1,000,000 unsecured revolving credit facility; (2) our $400,000 unsecured term loan; (3) an aggregate outstanding principal amount of $2,600,000 of public issuances of unsecured senior notes; and (4) our public issuance of $8,478 outstanding principal amount of convertible senior unsecured notes. Our $1,000,000 revolving credit facility is available for general business purposes, including acquisitions. The maturity date of our revolving credit facility is July 15, 2018 and, subject to our payment of an extension fee and meeting other conditions, we have the option to extend the stated maturity date of our revolving credit facility by one year to July 15, 2019. We can borrow, repay and reborrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. We are required to pay interest on borrowings under our revolving credit facility at an annual rate of LIBOR plus a premium, which was 110 basis points as of September 30, 2016. We also pay a facility fee on the total amount of lending commitments, which was 20 basis points per annum at September 30, 2016 under our revolving credit facility. Both the interest rate premium and the facility fee are subject to adjustment based upon changes to our credit ratings. As of September 30, 2016, the annual interest rate for the amount outstanding under our revolving credit facility was 1.62%. The weighted average annual interest rate for borrowings under our revolving credit facility was 1.60% and 1.55% for the three and nine months ended September 30, 2016, respectively, and 1.30% and 1.28% for the three and nine months ended September 30, 2015, respectively. As of September 30, 2016 and November 8, 2016, we had $150,000 and $70,000 outstanding under our revolving credit facility, respectively. Our $400,000 term loan, which matures on April 15, 2019, is prepayable without penalty at any time. We are required to pay interest on the amounts under our term loan at a rate of LIBOR plus a premium, which was 120 basis points as of September 30, 2016. The interest rate premium is subject to adjustment based on changes to our credit ratings. As of September 30, 2016, the annual interest rate for the amount outstanding under our term loan was 1.72%. The weighted average annual interest rate for borrowings under our term loan was 1.69% and 1.65% for the three and nine months ended September 30, 2016, respectively, and 1.39% and 1.38% for the three and nine months ended September 30, 2015, respectively. Our credit agreement for our revolving credit facility and term loan also includes a feature under which maximum aggregate borrowings may be increased up to $2,300,000 on a combined basis in certain circumstances. Our credit agreement for our revolving credit facility and term loan and our 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 for our revolving credit facility and term loan and our 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 for our revolving credit facility and term loan and our senior notes indentures and their supplements at September 30, 2016. On February 3, 2016, we issued $750,000 aggregate principal amount of senior notes in public offerings, which included $400,000 aggregate principal amount of 4.25% senior notes due 2021 and $350,000 aggregate principal amount 5.25% senior notes due 2026. Net proceeds from these offerings were $731,506 after original issue discounts and offering expenses. On March 11, 2016, we redeemed at par all of our outstanding 6.30% senior notes due 2016 for a redemption price equal to the principal amount of $275,000, plus accrued and unpaid interest (an aggregate of $279,139). As a result of the redemption, we recorded a loss on early extinguishment of debt of $70 in the nine months ended September 30, 2016, which represented the unamortized discounts and issuance costs of these notes. On September 26, 2016, we redeemed at par all of our outstanding 5.625% senior notes due 2017 for a redemption price equal to the principal amount of $300,000, plus accrued and unpaid interest (an aggregate of $300,516). As a result of the redemption, we recorded a loss on early extinguishment of debt of $158 in the three and nine months ended September 30, 2016, which represented the unamortized discounts and issuance costs of these notes.

Indebtedness

Our principal debt obligations at September 30, 2016 were: (1) $150,000 of outstanding borrowings under our $1,000,000 unsecured revolving credit facility; (2) our $400,000 unsecured term loan; (3) an aggregate outstanding principal amount of $2,600,000 of public issuances of unsecured senior notes; and (4) our public issuance of $8,478 outstanding principal amount of convertible senior unsecured notes.

Our $1,000,000 revolving credit facility is available for general business purposes, including acquisitions. The maturity date of our revolving credit facility is July 15, 2018 and, subject to our payment of an extension fee and meeting other conditions, we have the option to extend the stated maturity date of our revolving credit facility by one year to July 15, 2019. We can borrow, repay and reborrow funds available under our revolving credit facility until maturity, and no principal repayment is due until maturity. We are required to pay interest on borrowings under our revolving credit facility at an annual rate of LIBOR plus a premium, which was 110 basis points as of September 30, 2016. We also pay a facility fee on the total amount of lending commitments, which was 20 basis points per annum at September 30, 2016 under our revolving credit facility. Both the interest rate premium and the facility fee are subject to adjustment based upon changes to our credit ratings. As of September 30, 2016, the annual interest rate for the amount outstanding under our revolving credit facility was 1.62%. The weighted average annual interest rate for borrowings under our revolving credit facility was 1.60% and 1.55% for the three and nine months ended September 30, 2016, respectively, and 1.30% and 1.28% for the three and nine months ended September 30, 2015, respectively. As of September 30, 2016 and November 8, 2016, we had $150,000 and $70,000 outstanding under our revolving credit facility, respectively.

Our $400,000 term loan, which matures on April 15, 2019, is prepayable without penalty at any time. We are required to pay interest on the amounts under our term loan at a rate of LIBOR plus a premium, which was 120 basis points as of September 30, 2016. The interest rate premium is subject to adjustment based on changes to our credit ratings. As of September 30, 2016, the annual interest rate for the amount outstanding under our term loan was 1.72%. The weighted average annual interest rate for borrowings under our term loan was 1.69% and 1.65% for the three and nine months ended September 30, 2016, respectively, and 1.39% and 1.38% for the three and nine months ended September 30, 2015, respectively.

Our credit agreement for our revolving credit facility and term loan also includes a feature under which maximum aggregate borrowings may be increased up to $2,300,000 on a combined basis in certain circumstances. Our credit agreement for our revolving credit facility and term loan and our 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 for our revolving credit facility and term loan and our 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 for our revolving credit facility and term loan and our senior notes indentures and their supplements at September 30, 2016.

On February 3, 2016, we issued $750,000 aggregate principal amount of senior notes in public offerings, which included $400,000 aggregate principal amount of 4.25% senior notes due 2021 and $350,000 aggregate principal amount 5.25% senior notes due 2026. Net proceeds from these offerings were $731,506 after original issue discounts and offering expenses.

On March 11, 2016, we redeemed at par all of our outstanding 6.30% senior notes due 2016 for a redemption price equal to the principal amount of $275,000, plus accrued and unpaid interest (an aggregate of $279,139). As a result of the redemption, we recorded a loss on early extinguishment of debt of $70 in the nine months ended September 30, 2016, which represented the unamortized discounts and issuance costs of these notes.

On September 26, 2016, we redeemed at par all of our outstanding 5.625% senior notes due 2017 for a redemption price equal to the principal amount of $300,000, plus accrued and unpaid interest (an aggregate of $300,516). As a result of the redemption, we recorded a loss on early extinguishment of debt of $158 in the three and nine months ended September 30, 2016, which represented the unamortized discounts and issuance costs of these notes.