XML 111 R85.htm IDEA: XBRL DOCUMENT
v3.20.4

Subsequent Events (Details) - USD ($) $ in Thousands |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Feb. 14, 2021 | Feb. 05, 2021 | Feb. 02, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Jan. 29, 2021
Subsequent Event [Line Items] |  |  |  |  |  |  |
Common stock, shares issued |  |  |  | 155,797,725 | 154,869,198 |  |
Repayments of Unsecured Debt |  |  |  | $ 0 | $ 699,237 | $ 699,517 |
Boston Properties Limited Partnership |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Repayments of Unsecured Debt |  |  |  | 0 | $ 699,237 | $ 699,517 |
Boston Properties Limited Partnership | Senior Notes |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Debt |  |  |  | 9,700,000 |  |  |
Boston Properties Limited Partnership | 4.289% unsecured senior notes | Senior Notes |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Debt |  |  |  | $ 850,000 |  |  |
Debt Instrument, Interest Rate, Stated Percentage |  |  |  | 4.125% |  |  |
Restricted Stock [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Common stock, shares issued |  |  |  | 29,630 | 26,503 | 20,320 |
LTIP Units [Member] | Boston Properties Limited Partnership |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Number of shares issued |  |  |  | 207,181 | 181,919 | 205,838 |
Subsequent Event [Member] | Boston Properties Limited Partnership | 4.289% unsecured senior notes | Senior Notes |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Debt | $ 850,000 |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage | 4.125% |  |  |  |  |  |
Repayments of Unsecured Debt | $ 858,700 |  |  |  |  |  |
Debt Instrument, Increase, Accrued Interest | $ 8,700 |  |  |  |  |  |
Subsequent Event [Member] | Restricted Stock [Member] |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Common stock, shares issued |  |  |  |  |  |  | 33,449
Subsequent Event [Member] | LTIP Units [Member] | Boston Properties Limited Partnership |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Number of shares issued |  |  | 263,527 |  |  |  |
Subsequent Event [Member] | MYLTIP 2021 |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Value of MYLTIP Awards |  |  | $ 15,300 |  |  |  |
Minimum earned awards |  |  | 0 |  |  |  |
Maximum Earned Awards |  |  | 352,021 |  |  |  |
Earned awards - Target |  |  | 176,009 |  |  |  |
Subsequent Event [Member] | MYLTIP 2018 |  |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |  |
Value of MYLTIP Awards |  | $ 4,600 |  |  |  |  |
Forfeitures, in units |  | 285,925 |  |  |  |  |
Final awards percentage of target |  | 29.20% |  |  |  |  |

X
- Definition Earned wards - Target + References No definition available. + Details
Name: | bxp_EarnedwardsTarget
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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 Maximum Earned Awards + References No definition available. + Details
Name: | bxp_MaximumEarnedAwards
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum earned awards + References No definition available. + Details
Name: | bxp_Minimumearnedawards
Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

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 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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031897-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(16)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(22)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(16)) -URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878 + Details
Name: | us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Increase for accrued, but unpaid interest on the debt instrument for the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(f)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690 + Details
Name: | us-gaap_DebtInstrumentIncreaseAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash outflow to repay long-term debt that is not secured by collateral. Excludes repayments of tax exempt unsecured debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585 + Details
Name: | us-gaap_RepaymentsOfUnsecuredDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Number of shares under non-option equity instrument agreements that were cancelled as a result of occurrence of a terminating event. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(3) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsForfeitures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares issued under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event. + References No definition available. + Details
Name: | us-gaap_SubsequentEventLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=bxp_BostonPropertiesLimitedPartnershipMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LongtermDebtTypeAxis=us-gaap_SeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=bxp_FourPointTwoEightNinePercentUnsecuredSeniorNotesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=bxp_LTIPUnitsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=bxp_MYLTIPTwoThousandTwentyOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=bxp_MYLTIPTwoThousandEighteenMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |