XML 61 R45.htm IDEA: XBRL DOCUMENT
v3.21.2

Investment in Unconsolidated Real Estate Ventures - Textual (Details) $ in Thousands |  | 3 Months Ended | 9 Months Ended |  |  |
--- | --- | --- | --- | --- | --- | ---
Feb. 02, 2021 USD ($) | Sep. 30, 2021 USD ($) a ft² property apartment | Sep. 30, 2020 USD ($) | Sep. 30, 2021 USD ($) a ft² property apartment | Sep. 30, 2020 USD ($) | Jul. 23, 2021 USD ($) | Feb. 02, 2021 ft² | Feb. 02, 2021 a | Feb. 02, 2021 | Dec. 31, 2020 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of real estate properties | property |  | 81 |  | 81 |  |  |  |  |  |
Investment in unconsolidated real estate ventures |  | $ 449,658 |  | $ 449,658 |  |  |  |  |  | $ 401,327
Accounts receivable |  | 11,645 |  | 11,645 |  |  |  |  |  | 13,536
Investment in real estate ventures |  | $ 427,411 |  | $ 427,411 |  |  |  |  |  | 389,811
Brandywine Al Venture L L C | Fairview Properties |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership percentage |  | 50.00% |  | 50.00% |  |  |  |  |  |
Impairment charge |  | $ 1,100 |  |  |  |  |  |  |  |
Brandywine Al Venture L L C | Fairview Properties | Brandywine Realty Trust |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Impairment charge |  | 600 |  |  |  |  |  |  |  |
3025 JFK Venture |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Area of land (in acres) |  |  |  |  |  |  | 1 | 1 |  |
Equity method investment, ownership percentage |  |  |  |  |  |  |  |  | 55.00% |
Lease agreement term | 99 years |  |  |  |  |  |  |  |  |
Investment in real estate ventures | $ 34,800 |  |  |  |  |  |  |  |  |
Area of building to be constructed | ft² |  |  |  |  |  |  | 570,000 |  |  |
Estimated project cost | 287,300 |  |  |  |  |  |  |  |  |
Joint venture, funding committed by other party | $ 45,200 |  |  |  |  |  |  |  |  |
Ownership interest held by partner |  |  |  |  |  |  |  |  | 45.00% |
Joint venture, funding committed |  | 20,500 |  | $ 20,500 |  |  |  |  |  |
Construction loan amount |  |  |  |  |  | $ 186,700 |  |  |  |
3025 JFK Venture | LIBOR |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Construction loan, interest rate |  |  |  |  |  | 3.50% |  |  |  |
Interest rate, floor |  |  |  |  |  | 0.25% |  |  |  |
Real Estate Venture |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Accounts receivable |  | 2,000 |  | 2,000 |  |  |  |  |  | $ 1,200
Management Fees | Real Estate Venture |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Service and other revenue |  | 2,100 | $ 1,300 | 6,200 | $ 3,200 |  |  |  |  |
Leasing Commission Income | Real Estate Venture |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Service and other revenue |  | $ 700 | $ 200 | $ 2,600 | $ 900 |  |  |  |  |
Minimum |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership percentage |  | 15.00% |  | 15.00% |  |  |  |  |  |
Maximum |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Equity method investment, ownership percentage |  | 70.00% |  | 70.00% |  |  |  |  |  |
Unconsolidated Real Estate Ventures |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Investment in unconsolidated real estate ventures |  | $ 427,400 |  | $ 427,400 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Office properties |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of unconsolidated investments in Real Estate Ventures | property |  | 5 |  | 5 |  |  |  |  |  |
Rentable area (in square feet) | ft² |  | 8,400,000 |  | 8,400,000 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Other Liabilities |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Investment in unconsolidated real estate ventures |  | $ 22,200 |  | $ 22,200 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Unconsolidated Properties |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of real estate properties | property |  | 10 |  | 10 |  |  |  |  |  |
Number of properties with negative investment balances | property |  | 1 |  | 1 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Land Held For Development |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of unconsolidated investments in Real Estate Ventures | property |  | 2 |  | 2 |  |  |  |  |  |
Area of land (in acres) | a |  | 1.4 |  | 1.4 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Land Under Active Development |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of unconsolidated investments in Real Estate Ventures | property |  | 1 |  | 1 |  |  |  |  |  |
Area of land (in acres) | a |  | 1.0 |  | 1.0 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Mixed Use Tower |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of unconsolidated investments in Real Estate Ventures | property |  | 1 |  | 1 |  |  |  |  |  |
Rentable area (in square feet) | ft² |  | 200,000 |  | 200,000 |  |  |  |  |  |
Number of apartment units (in units) | apartment |  | 250 |  | 250 |  |  |  |  |  |
Unconsolidated Real Estate Ventures | Residential Tower |  |  |  |  |  |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |  |  |  |  |  |
Number of unconsolidated investments in Real Estate Ventures | property |  | 1 |  | 1 |  |  |  |  |  |
Number of apartment units (in units) | apartment |  | 321 |  | 321 |  |  |  |  |  |

X
- Definition Area Of Building To Be Constructed + References No definition available. + Details
Name: | bdn_AreaOfBuildingToBeConstructed
Namespace Prefix: | bdn_
Data Type: | dtr-types:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Capital Commitment Targets, Construction Loan Amount + References No definition available. + Details
Name: | bdn_CapitalCommitmentTargetsConstructionLoanAmount
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Debt Instrument, Interest Rate Floor + References No definition available. + Details
Name: | bdn_DebtInstrumentInterestRateFloor
Namespace Prefix: | bdn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Estimated Project Cost + References No definition available. + Details
Name: | bdn_EstimatedProjectCost
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Joint Venture, Additional Funding Committed + References No definition available. + Details
Name: | bdn_JointVentureAdditionalFundingCommitted
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Joint Venture, Additional Funding Committed By Other Party + References No definition available. + Details
Name: | bdn_JointVentureAdditionalFundingCommittedByOtherParty
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Lease agreement term. + References No definition available. + Details
Name: | bdn_LeaseAgreementTerm
Namespace Prefix: | bdn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Real Estate Properties With Negative Investment Balances + References No definition available. + Details
Name: | bdn_NumberOfRealEstatePropertiesWithNegativeInvestmentBalances
Namespace Prefix: | bdn_
Data Type: | xbrli:integerItemType
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 Real Estate Investment, Ownership Interest Held By Partner + References No definition available. + Details
Name: | bdn_RealEstateInvestmentOwnershipInterestHeldByPartner
Namespace Prefix: | bdn_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 954 -SubTopic 310 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=123366838&loc=d3e3073-115593 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(5)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_AccountsReceivableNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 1B -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611 Reference 2: 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: | dtr-types: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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 323 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=109237563&loc=d3e33749-111570 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 25 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8813-108599 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 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_EquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=123351718&loc=d3e2611-110228 + Details
Name: | us-gaap_ImpairmentOfLongLivedAssetsToBeDisposedOf
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net rentable area for properties owned. + References No definition available. + Details
Name: | us-gaap_NetRentableArea
Namespace Prefix: | us-gaap_
Data Type: | dtr-types: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
- Definition The book value of investments in real estate joint ventures including direct and indirect investments. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1(d)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 + Details
Name: | us-gaap_RealEstateInvestmentsJointVentures
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, including tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value-added and excise. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 41 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9038-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130545-203045 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 32 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8933-108599 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 30 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8906-108599 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e8736-108599 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130543-203045 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9054-108599 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 40 -URI http://asc.fasb.org/extlink&oid=123359005&loc=d3e9031-108599 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 924 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 11.L) -URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856 + Details
Name: | us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bdn_BrandywineAlVentureLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | srt_OwnershipAxis=bdn_BrandywineRealtyTrustMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bdn_A3025JFKBoulevardMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentSecondaryCategorizationAxis=bdn_RealEstateVentureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=bdn_ManagementFeesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ProductOrServiceAxis=bdn_LeaseCommissionIncomeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=srt_OfficeBuildingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_OtherLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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