XML 69 R52.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) - USD ($) $ in Thousands | May 12, 2016 | Jun. 30, 2017 | Jun. 06, 2017 | Dec. 31, 2016
--- | --- | --- | --- | ---
Noncontrolling Interest [Line Items] |  |  |  |
Noncontrolling Interest in Limited Partnerships |  | $ 1,653,981 |  | $ 1,530,647
Salesforce Tower[Member] | Consolidated Properties [Member] |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |
Portion of project costs covered by a construction loan | 50.00% |  |  |
Portion of costs funded (in percentage) | 50.00% |  |  |
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners | 5.00% |  |  |
Debt Instrument, Basis Spread on Variable Rate | 3.00% |  |  |
Salesforce Tower[Member] | Parent Company [Member] | Consolidated Properties [Member] |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |
Costs funded (in percentage) | 2.50% |  |  |
Preferred equity funded |  | $ 13,500 |  |
767 Fifth Avenue (the General Motors Building) | Consolidated Properties [Member] |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |
Noncontrolling Interest in Limited Partnerships |  |  | $ 109,600 |
Ownership Percentage by the Company |  |  | 60.00% |
Unpaid principal balance of the members' notes payable contributed to equity |  |  | $ 273,900 |
767 Fifth Avenue (the General Motors Building) | Consolidation, Eliminations [Member] | Consolidated Properties [Member] |  |  |  |
Noncontrolling Interest [Line Items] |  |  |  |
Unpaid principal balance of the members' notes payable contributed to equity |  |  | $ 164,400 |

X
- Definition Costs funded (in percentage) + References No definition available. + Details
Name: | bxp_Costsfundedinpercentage
Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Portion of costs funded (in percentage) + References No definition available. + Details
Name: | bxp_Portionofcostsfundedinpercentage
Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Portion of project costs covered by a construction loan + References No definition available. + Details
Name: | bxp_Portionofprojectcostscoveredbyaconstructionloan
Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Preferred equity funded + References No definition available. + Details
Name: | bxp_Preferredequityfunded
Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Unpaid principal balance of the members' notes payable contributed to equity + References No definition available. + Details
Name: | bxp_Unpaidprincipalbalanceofthemembersnotespayablecontributedtoequity
Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying amount of the equity interests owned by noncontrolling partners of a limited partnership included in the entity's consolidated financial statements. + References No definition available. + Details
Name: | us-gaap_MinorityInterestInLimitedPartnerships
Namespace Prefix: | us-gaap_
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_MinorityInterestLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The parent entity's interest in net assets of the subsidiary, expressed as a percentage. + References No definition available. + Details
Name: | us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_VariableInterestEntitiesByClassificationOfEntityAxis=bxp_SalesforeceTowerformerlyTransbayTowerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RealEstatePropertiesAxis=us-gaap_ConsolidatedPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_SevensixsevenfifthavenuethegeneralmotorsbuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConsolidationItemsAxis=us-gaap_ConsolidationEliminationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |