XML 51 R34.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2018 USD ($) ft² Land_Parcels Buildings payments | Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |
Mortgage notes payable, net |  | $ 2,972,052 | $ 2,979,281
Carrying Value of investment |  | (462,869) | (443,980)
Carrying value of the Company's investments in unconsolidated joint ventures |  | $ 682,507 | 619,925
Square 407 Limited Partnership [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | Market Square North |
Ownership Percentage |  | 50.00% |
Carrying Value of investment | [1] | $ (7,371) | (8,258)
The Metropolitan Square Associates LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | Metropolitan Square |
Ownership Percentage |  | 20.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 4,628 | 3,339
BP/CRF 901 New York Avenue LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | 901 New York Avenue |
Ownership Percentage | [2] | 25.00% |
Carrying Value of investment | [1] | $ (12,824) | (13,811)
WP Project Developer LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | Wisconsin Place Land and Infrastructure |
Ownership Percentage | [3] | 33.30% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 39,015 | 39,710
Annapolis Junction NFM, LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | Annapolis Junction |
Ownership Percentage | [4] | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 17,597 | 18,381
Number of real estate properties | Buildings |  | 4 |
Parcels of undeveloped land | Land_Parcels |  | 2 |
540 Madison Venture LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | 540 Madison Avenue |
Ownership Percentage |  | 60.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 66,385 | 66,179
500 North Capitol Venture LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | 500 North Capitol Street, NW |
Ownership Percentage |  | 30.00% |
Carrying Value of investment | [1] | $ (4,416) | (3,876)
501 K Street LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | 1001 6th Street |
Ownership Percentage | [5] | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 42,646 | 42,657
Potential additonal payments to joint venture partner | payments |  | 2 |
Minimum square footage to make a potential additional payment to joint venture partner (in sqft) | ft² |  | 520,000 |
Podium Developer LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | The Hub on Causeway |
Ownership Percentage |  | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 72,900 | 67,120
Residential Tower Developer LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | The Hub on Causeway - Residential |
Ownership Percentage | [6] | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 38,958 | 28,212
Hotel Tower Developer LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | The Hub on Causeway - Hotel Air Rights |
Ownership Percentage |  | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 2,046 | 1,690
1265 Main Office JV LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | 1265 Main Street |
Ownership Percentage |  | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 4,413 | 4,641
BNY Tower Holdings LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | Dock 72 at the Brooklyn Navy Yard |
Ownership Percentage |  | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 71,651 | 72,104
CA-Colorado Center Limited Partnership [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | Colorado Center |
Ownership Percentage |  | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 253,864 | 254,440
7750 Wisconsin Avenue LLC [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Properties |  | 7750 Wisconsin Avenue |
Ownership Percentage | [6] | 50.00% |
Carrying value of the Company's investments in unconsolidated joint ventures | [1] | $ 68,404 | 21,452
Unconsolidated Joint Ventures [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Carrying Value of investment |  | 24,600 | 25,900
Unconsolidated Joint Ventures [Member] |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Mortgage notes payable, net |  | 1,524,951 | 1,437,440
Carrying Value of investment |  | (126,179) | (99,215)
Carrying value of the Company's investments in unconsolidated joint ventures | [1],[7] | $ 657,896 | $ 593,980
[1] | Investments with deficit balances aggregating approximately $24.6 million and $25.9 million at June 30, 2018 and December 31, 2017, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
[2] | The Company’s economic ownership has increased based on the achievement of certain return thresholds.
[3] | The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.3% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project.
[4] | The joint venture owns four in-service buildings and two undeveloped land parcels.
[5] | Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.
[6] | This entity is a VIE (See Note 2).
[7] | Investments with deficit balances aggregating approximately $24.6 million and $25.9 million at June 30, 2018 and December 31, 2017, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheet

X
- Definition Minimum square footage to make a potential additional payment to joint venture partner (in sqft) + References No definition available. + Details
Name: | bxp_Minimumsquarefootagetomakeapotentialadditionalpaymenttojointventurepartnerinsqft
Namespace Prefix: | bxp_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Name of Joint Venture Property + References No definition available. + Details
Name: | bxp_NameOfJointVentureProperty
Namespace Prefix: | bxp_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Parcels of undeveloped land + References No definition available. + Details
Name: | bxp_ParcelsOfUndevelopedLand
Namespace Prefix: | bxp_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Potential additonal payments to joint venture partner + References No definition available. + Details
Name: | bxp_Potentialadditonalpaymentstojointventurepartner
Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=66011266&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The number of real estate properties owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfRealEstateProperties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of liabilities classified as other. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_OtherLiabilities
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_ScheduleOfEquityMethodInvestmentsLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -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=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -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=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(16)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_SecuredDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_SquareFourZeroSevenLimitedPartnershipMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_MetropolitanSquareAssociatesLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_BpCrfNineZeroOneNewYorkAvenueLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_WpProjectDeveloperLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_AnnapolisJunctionNfmLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_FiveFourZeroMadisonVentureLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_FiveZeroZeroNorthCapitolLlcMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_FivezerooneKStreetLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_PodiumDeveloperLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_ResidentialTowerDeveloperLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_HotelTowerDeveloperLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_OneTwoSixFiveMainOfficeJVLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_BNYTowerHoldingsLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_CAColoradoCenterLimitedPartnershipMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bxp_SevenSevenFiveZeroWisconsinAvenueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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