Common Stock Weighted Average Price.

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- Definition

Employee and director payment per share

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No definition available.

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- Definition

Final awards percentage of target

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No definition available.

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- Definition

LTIP units issued

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No definition available.

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- Definition

Value Of LTIP Units Issued.

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No definition available.

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- Definition

Value of MYLTIP Awards

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No definition available.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
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- Definition

Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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- Definition

Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

+ References

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- Definition

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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- Definition

Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

Per share or unit weighted-average intrinsic value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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- Definition

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

+ References

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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- Definition

Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

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- Definition

Number of shares issued under share-based payment arrangement.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Stock Option and Incentive Plan Stock and Units (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended		9 Months Ended
	Feb. 05, 2021	Feb. 02, 2021	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued			156,285,391		156,285,391		155,797,725
Stock based compensation expense			$ 8,400	$ 8,000	$ 42,200	$ 35,300
Common Stock, Value, Issued			$ 1,562		$ 1,562		$ 1,557
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued			56,841		56,841
LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value Of LTIP Units Issued					$ 23,800
Expected life assumed to calculate per unit fair value per LTIP unit (in years)					5 years 8 months 12 days
Risk-free rate					0.65%
Expected price volatility					30.00%
Weighted average price (per unit)			$ 84.43		$ 84.43
MYLTIP 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Final awards percentage of target	29.20%
Value of MYLTIP Awards	$ 4,600
Forfeitures, in units	285,925
MYLTIP 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Period		3 years
Value of MYLTIP Awards		$ 15,300
Boston Properties Limited Partnership \| LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares)			281,640		281,640
Boston Properties Limited Partnership \| MYLTIP 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares issued					352,021
Boston Properties Limited Partnership \| MYLTIP 2021 \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock available for issuance		352,021
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share)					$ 0.01
Common Stock, Value, Issued			$ 5,700		$ 5,700
Common Stock Weighted Average Price (in dollars per share)			$ 100.46		$ 100.46
LTIP and MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share)					$ 0.25
Ltips (including vested MYLTIPS) And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses			$ 28,400		$ 28,400
Unvested MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses			$ 9,400		$ 9,400
Weighted-average period (years)					2 years 1 month 6 days