Subsequent Events	12 Months Ended
Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	20. Subsequent Events On January 4, 2016 and January 6, 2016, 767 Fifth Partners LLC, the consolidated entity in which the Company has a 60% interest and owns 767 Fifth Avenue (the General Motors Building) in New York City, entered into two forward-starting interest rate swap contracts which fix the 10-year swap rate at an average of 2.403% per annum on notional amounts aggregating $50.0 million. The interest rate swap contracts were entered into in advance of a financing with a target commencement date in June 2017 and maturity in June 2027 (See Note 7). On January 20, 2016, Boston Properties Limited Partnership completed a public offering of $1.0 billion in aggregate principal amount of its 3.650% senior unsecured notes due 2026. The notes were priced at 99.708% of the principal amount to yield an effective rate (including financing fees) of 3.766% to maturity. The notes will mature on February 1, 2026, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $988.9 million after deducting underwriting discounts and estimated transaction expenses. On January 25, 2016, Boston Properties, Inc.’s Compensation Committee approved the 2016 Multi-Year, Long-Term Incentive Program (the “2016 MYLTIP”) awards under Boston Properties, Inc.’s 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2016 MYLTIP awards utilize Boston Properties, Inc.’s total stockholder return (“TSR”) over a three-year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards will be based on Boston Properties, Inc.’s TSR relative to (i) the Cohen & Steers Realty Majors Portfolio Index (50% weight) and (ii) the NAREIT Office Index adjusted to include Vornado Realty Trust and exclude Boston Properties, Inc. (50% weight). Earned awards will range from zero to a maximum of approximately $49.3 million depending on Boston Properties, Inc.’s TSR relative to the two indices, with three tiers (threshold: approximately $9.9 million; target: approximately $19.7 million; high: approximately $49.3 million) and linear interpolation between tiers. Earned awards measured on the basis of relative TSR performance are subject to an absolute TSR component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.’s annualized TSR is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.’s annualized TSR is more than 12% even though on a relative basis alone Boston Properties, Inc.’s TSR would not result in any earned awards. Earned awards (if any) will vest 50% on February 9, 2019 and 50% on February 9, 2020, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, or termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 9, 2019, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2016 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units. Under ASC 718, the 2016 MYLTIP awards have an aggregate value of approximately $17.3 million, which amount will generally be amortized into earnings over the four-year plan period under the graded vesting method. On February 1, 2016, the Company completed the sale of its 415 Main Street property located in Cambridge, Massachusetts to the tenant for a gross sale price of approximately $105.4 million, which exceeds its carrying value. As part of its lease signed on July 14, 2004, the tenant was granted a fixed price option to purchase the building at the beginning of the 11th lease year, which option was exercised by the tenant on October 22, 2014. 415 Main Street is an office/technical property with approximately 231,000 net rentable square feet. On February 3, 2016, the Company entered into a lease termination agreement with a tenant for an approximately 85,000 square foot lease at its 250 West 55th Street property located in New York City. The lease was scheduled to expire on February 28, 2035. In consideration for the termination of the lease, the tenant paid the Company approximately $45.0 million, which will be recognized during the three months ending March 31, 2016. On February 4, 2016, the measurement period for the Company’s 2013 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 109.5% of target or an aggregate of approximately $13.5 million. On February 8, 2016, Boston Properties, Inc. issued 18,521 shares of restricted common stock and Boston Properties Limited Partnership issued 139,435 LTIP units under the 2012 Plan to certain employees of Boston Properties, Inc.

20. Subsequent Events

On January 4, 2016 and January 6, 2016, 767 Fifth Partners LLC, the consolidated entity in which the Company has a 60% interest and owns 767 Fifth Avenue (the General Motors Building) in New York City, entered into two forward-starting interest rate swap contracts which fix the 10-year swap rate at an average of 2.403% per annum on notional amounts aggregating $50.0 million. The interest rate swap contracts were entered into in advance of a financing with a target commencement date in June 2017 and maturity in June 2027 (See Note 7).

On January 20, 2016, Boston Properties Limited Partnership completed a public offering of $1.0 billion in aggregate principal amount of its 3.650% senior unsecured notes due 2026. The notes were priced at 99.708% of the principal amount to yield an effective rate (including financing fees) of 3.766% to maturity. The notes will mature on February 1, 2026, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $988.9 million after deducting underwriting discounts and estimated transaction expenses.

On January 25, 2016, Boston Properties, Inc.’s Compensation Committee approved the 2016 Multi-Year, Long-Term Incentive Program (the “2016 MYLTIP”) awards under Boston Properties, Inc.’s 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2016 MYLTIP awards utilize Boston Properties, Inc.’s total stockholder return (“TSR”) over a three-year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards will be based on Boston Properties, Inc.’s TSR relative to (i) the Cohen & Steers Realty Majors Portfolio Index (50% weight) and (ii) the NAREIT Office Index adjusted to include Vornado Realty Trust and exclude Boston Properties, Inc. (50% weight). Earned awards will range from zero to a maximum of approximately $49.3 million depending on Boston Properties, Inc.’s TSR relative to the two indices, with three tiers (threshold: approximately $9.9 million; target: approximately $19.7 million; high: approximately $49.3 million) and linear interpolation between tiers. Earned awards measured on the basis of relative TSR performance are subject to an absolute TSR component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.’s annualized TSR is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.’s annualized TSR is more than 12% even though on a relative basis alone Boston Properties, Inc.’s TSR would not result in any earned awards. Earned awards (if any) will vest 50% on February 9, 2019 and 50% on February 9, 2020, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, or termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 9, 2019, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2016 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units. Under ASC 718, the 2016 MYLTIP awards have an aggregate value of approximately $17.3 million, which amount will generally be amortized into earnings over the four-year plan period under the graded vesting method.

On February 1, 2016, the Company completed the sale of its 415 Main Street property located in Cambridge, Massachusetts to the tenant for a gross sale price of approximately $105.4 million, which exceeds its carrying value. As part of its lease signed on July 14, 2004, the tenant was granted a fixed price option to purchase the building at the beginning of the 11th lease year, which option was exercised by the tenant on October 22, 2014. 415 Main Street is an office/technical property with approximately 231,000 net rentable square feet.

On February 3, 2016, the Company entered into a lease termination agreement with a tenant for an approximately 85,000 square foot lease at its 250 West 55th Street property located in New York City. The lease was scheduled to expire on February 28, 2035. In consideration for the termination of the lease, the tenant paid the Company approximately $45.0 million, which will be recognized during the three months ending March 31, 2016.

On February 4, 2016, the measurement period for the Company’s 2013 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 109.5% of target or an aggregate of approximately $13.5 million.

On February 8, 2016, Boston Properties, Inc. issued 18,521 shares of restricted common stock and Boston Properties Limited Partnership issued 139,435 LTIP units under the 2012 Plan to certain employees of Boston Properties, Inc.