XML 108 R86.htm IDEA: XBRL DOCUMENT
v3.20.4

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - 4040 Wilson Venture (Details) $ in Thousands |  | 12 Months Ended |
--- | --- | --- | ---
Jul. 31, 2013 USD ($) a ft² property | Dec. 31, 2020 USD ($) ft² property | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Area of real estate property | ft² |  | 13,852,464 |  |  |
Number of properties | property |  | 82 |  |  |
Cash paid to acquire real estate ventures |  | $ 0 | $ 2,181 | $ 0 |
Advanced under the construction loan |  | $ 719 | $ 253 | $ 908 |
4040 Wilson Venture |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Ownership percentage | 50.00% | 50.00% |  |  |
Area owned by real estate venture of undeveloped parcels of land | a | 1.3 |  |  |  |
Secured construction loan with total borrowing capacity |  |  |  |  | $ 150,000
Advanced under the construction loan |  | $ 141,900 |  |  |
Mixed Use Property | 4040 Wilson Venture |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Area of real estate property | ft² | 427,500 |  |  |  |
Number of properties | property | 8 |  |  |  |
Brandywine Realty Trust |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Ownership percentage |  | 50.00% |  |  |
Brandywine Realty Trust | 4040 Wilson Venture |  |  |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |  |  |
Cash paid to acquire real estate ventures | $ 36,000 |  |  |  |

X
- Definition Area owned by Real estate venture of undeveloped parcels of land (in acres). + References No definition available. + Details
Name: | bdn_AreaOwnedByRealEstateVentureOfUndevelopedParcelsOfLand
Namespace Prefix: | bdn_
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 Amount of unused borrowing capacity under the long-term financing arrangement that is available to the entity as of the balance sheet date. + References Reference 1: 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(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
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: | num:percentItemType
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 cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the investment in or advances to an entity in which the reporting entity shares control of the entity with another party or group. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireInterestInJointVenture
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_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=bdn_A4040WilsonVentureMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_MajorPropertyClassAxis=bdn_MixedUsePropertyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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