XML 80 R62.htm IDEA: XBRL DOCUMENT
v3.4.0.3

Subsequent Events subsequent Events (Details) $ in Thousands |  |  | 3 Months Ended |  |
--- | --- | --- | --- | --- | ---
Apr. 11, 2016 USD ($) ft² yr | Apr. 04, 2016 USD ($) ft² yr | Mar. 31, 2016 USD ($) | Mar. 31, 2015 USD ($) | Apr. 22, 2016 USD ($) ft² | Dec. 31, 2015 USD ($)
Subsequent Event [Line Items] |  |  |  |  |  |
Mortgage loan |  |  | $ 3,416,622 |  |  | $ 3,435,242
Repayments of Secured Debt |  |  | $ 6,265 | $ 7,024 |  |
Secured Debt [Member] | Fountain Square [Member] | Subsequent Event [Member] |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |
Repayments of Secured Debt | $ 211,300 |  |  |  |  |
Coupon/Stated Rate | 5.71% |  |  |  |  |
Annapolis Junction Building One [Member] | Secured Debt [Member] | Subsequent Event [Member] |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |
Ownership Percentage | 50.00% |  |  |  |  |
Mortgage loan | $ 40,000 |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 1.75% |  |  |  |  |
Number of extensions | 1 |  |  |  |  |
Extension Option (in years) | yr | 3 |  |  |  |  |
Net Rentable Area (in sf) | ft² | 118,000 |  |  |  |  |
Peterson Way [Member] | Subsequent Event [Member] |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  | 218,000 |
Purchase price |  |  |  |  | $ 78,000 |
Portion of Building Leased (percentage) |  |  |  |  | 100.00% |
Peterson Way [Member] | Future development [Member] | Subsequent Event [Member] |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |
Net Rentable Area (in sf) | ft² |  |  |  |  | 632,000 |
Construction Loans [Member] | Annapolis Junction Building Seven [Member] | Subsequent Event [Member] |  |  |  |  |  |
Subsequent Event [Line Items] |  |  |  |  |  |
Ownership Percentage |  | 50.00% |  |  |  |
Construction Loan |  | $ 21,500 |  |  |  |
Construction Loan Facility Borrowing Capacity |  | $ 22,000 |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 1.65% |  |  |  |
Number of extensions |  | 1 |  |  |  |
Extension Option (in years) | yr |  | 1 |  |  |  |
Net Rentable Area (in sf) | ft² |  | 127,000 |  |  |  |

X
- Definition Construction Loan Facility Borrowing Capacity + References No definition available. + Details
Name: | bxp_ConstructionLoanFacilityBorrowingCapacity
Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Extension Option (in years) + References No definition available. + Details
Name: | bxp_ExtensionOptioninyears
Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of extensions + References No definition available. + Details
Name: | bxp_Numberofextensions
Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Amount of assets acquired at the acquisition date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=56956791&loc=d3e4845-128472 + Details
Name: | us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents the carrying value of a short-term real estate loan to finance building costs. The funds are disbursed as needed or in accordance with a prearranged plan; generally, a portion of the funds is disbursed at inception and the remainder as construction progresses. The money is repaid on completion of the project, usually from the proceeds of a mortgage loan. The rate is normally higher than the prime rate, and there is usually an origination fee. The effective yield on these loans tends to be high, and the lender has a security interest in the real property. Note that there are separate concepts for the current and noncurrent portions of long-term construction loans. + 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 210.5-02.19(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20 -Article 5 + Details
Name: | us-gaap_ConstructionLoan
Namespace Prefix: | us-gaap_
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 Contractual interest rate for funds borrowed, under the debt agreement. + 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 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&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 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=6382943&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Net rentable area for properties owned. + References No definition available. + Details
Name: | us-gaap_NetRentableArea
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash outflow to repay long-term debt that is wholly or partially secured by collateral. Excludes repayments of tax exempt secured debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3291-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 + Details
Name: | us-gaap_RepaymentsOfSecuredDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 + Details
Name: | us-gaap_SecuredDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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: | us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=bxp_PetersonWayMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=bxp_FuturedevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ShortTermDebtTypeAxis=us-gaap_ConstructionLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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