XML 66 R57.htm IDEA: XBRL DOCUMENT
v3.19.3

(Common Units) (Narrative) (Details) $ / shares in Units, $ in Thousands |  | 9 Months Ended |
--- | --- | --- | ---
Feb. 09, 2019 USD ($) shares | Sep. 30, 2019 USD ($) shares yr $ / shares | Dec. 31, 2018 USD ($)
OP Units [Member] |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
OP Units for redemption (in shares) |  | 41,577 |
Redemption of OP units issued on conversion of LTIP Units (in shares) |  | 39,377 |
Restriction on redemption of OP Unit to Common Stock (in years) | yr |  | 1 |
Redemption of OP Unit equivalent to Common Stock (in shares) |  | 1 |
Common units of operating partnership if converted value | $ |  | $ 2,300,000 |
Closing price of common stock (in dollars per share) | $ / shares |  | $ 129.66 |
2016 MYLTIP [Member] |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
Final awards percentage of target | 69.50% |  |
Value of MYLTIP Awards | $ | $ 13,600 |  |
2016 MYLTIP Units Forfeited | 364,980 |  |
Boston Properties Limited Partnership |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
Common units of operating partnership if converted value | $ |  | $ 2,335,272 | $ 2,000,591
Boston Properties Limited Partnership | OP Units [Member] |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
MYLTIP distribution prior to measurement date |  | 10.00% |
Boston Properties Limited Partnership | 2017 MYLTIP [Member] |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
2017 MYLTIP (in units) |  | 394,921 |
Boston Properties Limited Partnership | 2018 MYLTIP [Member] |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
2018 MYLTIP (in units) |  | 336,195 |
Boston Properties Limited Partnership | 2019 MYLTIP [Member] |  |  |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |  |  |
2019 MYLTIPS (in units) |  | 220,734 |

X
- Definition Final awards percentage of target + References No definition available. + Details
Name: | bxp_Finalawardspercentageoftarget
Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition MYLTIP distribution prior to measurement date + References No definition available. + Details
Name: | bxp_MYLTIPdistributionpriortomeasurementdateasapercentageOfOpUnitDistributionPriorToMeasurementDate
Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition One OP Unit is equivalent to one common stock (share). + References No definition available. + Details
Name: | bxp_OpUnitEquivalenceToCommonStock
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Redemption Of OP Units Issued On Conversion Of LTIP Units + References No definition available. + Details
Name: | bxp_RedemptionOfOpUnitsIssuedOnConversionOfLtipUnits
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Restriction on redemption of OP unit to Common Stock + References No definition available. + Details
Name: | bxp_RestrictionOnRedemption
Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition 2018 MYLTIP + References No definition available. + Details
Name: | bxp_TwothousandeighteenMYLTIP
Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition 2019 MYLTIPS + References No definition available. + Details
Name: | bxp_TwothousandnineteenMYLTIPS
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition two thousand seventeen MYLTIP + References No definition available. + Details
Name: | bxp_TwothousandseventeenMYLTIP
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Value of MYLTIP Awards + References No definition available. + Details
Name: | bxp_ValueOfMyltipAwards
Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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. + References No definition available. + Details
Name: | us-gaap_ConsolidationLessThanWhollyOwnedSubsidiaryParentOwnershipInterestEffectsOfChangesNetLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition As of the reporting date, the carrying amount of noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. The noncontrolling interest holder's ownership (or holders' ownership) may be in the form of preferred shares (regardless of class), preferred partnership units (regardless of class), preferential membership interests, or any other form of preferred equity regardless of investee entity legal form. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph 14 -URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph (12)(c) -URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph 15 -URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 480 -SubTopic 10 -Section S99 -Paragraph 3A -Subparagraph (16)(c) -URI http://asc.fasb.org/extlink&oid=65877616&loc=SL6540498-122764 + Details
Name: | us-gaap_RedeemableNoncontrollingInterestEquityPreferredCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Price of a single share of a number of saleable stocks of a company. + References No definition available. + Details
Name: | us-gaap_SharePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares (or other type of equity) forfeited during the period. + References No definition available. + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationForfeited
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of stock bought back by the entity at the exercise price or redemption price. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644 + Details
Name: | us-gaap_StockRedeemedOrCalledDuringPeriodShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=bxp_OpUnitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=bxp_MYLTIPTwothousandsixteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=bxp_TwothousandseventeenMYLTIPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=bxp_TwothousandeighteenMYLTIPMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=bxp_MYLTIPtwothousandnineteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |