XML 53 R38.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Organization of The Parent Company and The Operating Partnership (Textual) (Details) - Sep. 30, 2017 ft² in Millions | Total | property | ft² | Real_Estate_Investment | a | Apartment_unit
--- | --- | --- | --- | --- | --- | ---
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 97 |  |  |  |
Office Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 82 |  |  |  |
Mixed Use Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 4 |  |  |  |
Retail Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 1 |  |  |  |
Core Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 87 |  |  |  |
Development Property [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 1 |  |  |  |
Redevelopment Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 3 |  |  |  |
Assets Held-for-sale [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Properties |  | 6 |  |  |  |
Unconsolidated Real Estate Ventures [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment |  |  |  | 13 |  |
Unconsolidated Real Estate Ventures [Member] | Seven Real Estate Ventures [Member] | Office Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment |  |  |  | 7 |  |
Rentable Square Feet | ft² |  |  | 7.8 |  |  |
Unconsolidated Real Estate Ventures [Member] | Four Real Estate Ventures [Member] | Land Held For Development [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment |  |  |  | 4 |  |
Acreage of land | a |  |  |  |  | 5.7 |
Unconsolidated Real Estate Ventures [Member] | Two Other Real Estate Ventures [Member] | Residential Tower One [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment |  |  |  | 1 |  |
Number of Property units |  | 345 |  |  |  | 345
Unconsolidated Real Estate Ventures [Member] | Two Other Real Estate Ventures [Member] | Residential Tower Two [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment |  |  |  | 1 |  |
Number of Property units |  | 321 |  |  |  | 321
Parent Company [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Ownership in the Operating Partnership | 99.20% |  |  |  |  |
Net Rentable Square Feet | ft² |  |  | 16.4 |  |  |
Area Owned by Company of Undeveloped Parcels of Land | a |  |  |  |  | 214 |
Area of Additional Undeveloped Parcels of Land With Option to Purchase | a |  |  |  |  | 60 |
Total Potential Development Capacity | ft² |  |  | 15.7 |  |  |
Wholly-owned Management Company Subsidiaries [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Net Rentable Square Feet | ft² |  |  | 26.4 |  |  |
Wholly-owned Management Company Subsidiaries [Member] | Partially Owned Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Net Rentable Square Feet | ft² |  |  | 10.0 |  |  |
Wholly-owned Management Company Subsidiaries [Member] | Wholly Owned Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Net Rentable Square Feet | ft² |  |  | 16.4 |  |  |
Wholly-owned Management Company Subsidiaries [Member] | Office and Industrial Properties [Member] | Partially Owned Properties [Member] |  |  |  |  |  |
Organization of The Parent Company and The Operating Partnership [Line Items] |  |  |  |  |  |
Net Rentable Square Feet | ft² |  |  | 10.0 |  |  |

X
- Definition Area of additional undeveloped parcels of land with option to purchase. + References No definition available. + Details
Name: | bdn_AreaOfAdditionalUndevelopedParcelsOfLandWithOptionToPurchase
Namespace Prefix: | bdn_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Area owned by Company of undeveloped parcels of land. + References No definition available. + Details
Name: | bdn_AreaOwnedByCompanyOfUndevelopedParcelsOfLand
Namespace Prefix: | bdn_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of unconsolidated investments in Real Estate Ventures. + References No definition available. + Details
Name: | bdn_NumberOfUnconsolidatedInvestmentsInRealEstateVentures
Namespace Prefix: | bdn_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Organization of The Parent Company and The Operating Partnership. + References No definition available. + Details
Name: | bdn_OrganizationOfParentCompanyAndOperatingPartnershipLineItems
Namespace Prefix: | bdn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of development that can be supported by undeveloped land + References No definition available. + Details
Name: | bdn_PotentialDevelopmentCapacity
Namespace Prefix: | bdn_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Area of land held. + References No definition available. + Details
Name: | us-gaap_AreaOfLand
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Area of a real estate property. + References No definition available. + Details
Name: | us-gaap_AreaOfRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | num:areaItemType
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
- 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 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 The number of units in a real estate property owned as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_NumberOfUnitsInRealEstateProperty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_MixedUsePropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_RetailSiteMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_CorePropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_DevelopmentPropertyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_RedevelopmentPropertyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DisposalGroupClassificationAxis=us-gaap_DisposalGroupHeldforsaleNotDiscontinuedOperationsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | invest_InvestmentHoldingAxis=bdn_SevenRealEstateVenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentHoldingAxis=bdn_FourRealEstateVentureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_LandHeldForDevelopmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | invest_InvestmentHoldingAxis=bdn_TwoOtherRealEstateVenturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_ResidentialTowerOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_ResidentialTowerTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_ConsolidatedEntitiesAxis=bdn_ManagementCompanySubsidiariesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=bdn_OfficeAndIndustrialPropertiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |