XML 57 R42.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Basis of Presentation (Textual) (Details) |  |  |  |  | 3 Months Ended | 9 Months Ended | 12 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Aug. 23, 2018 | Mar. 15, 2017 USD ($) ft² | Jul. 01, 2016 USD ($) a | Dec. 03, 2015 ft² | Sep. 30, 2018 USD ($) a Parcel | Sep. 30, 2017 USD ($) | Dec. 31, 2016 USD ($) | Sep. 30, 2018 USD ($) a Parcel | Sep. 30, 2017 USD ($) | Dec. 31, 2019 USD ($) | Jun. 30, 2018 USD ($) | Mar. 16, 2018 a | Dec. 31, 2017 USD ($) | Apr. 28, 2017 a | Jan. 30, 2017 a
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income tax provision |  |  |  |  | $ 0 | $ (793,000) |  | $ 158,000 | $ (1,032,000) |  |  |  |  |  |
Increase in operating cash flows |  |  |  |  |  |  |  | 9,831,000 | 8,361,000 |  |  |  |  |  |
Lease agreement variable income |  |  |  |  |  |  |  | 0 |  |  |  |  |  |  |
Third party management contracts assets outstanding |  |  |  |  | 0 |  |  | 0 |  |  |  |  |  |  |
Third party management contracts liabilities outstanding |  |  |  |  | 0 |  |  | 0 |  |  |  |  |  |  |
Proceeds from the sale of properties |  |  |  |  |  |  |  | 16,771,000 | 114,821,000 |  |  |  |  |  |
Assets held for sale, net |  |  |  |  | 297,194,000 |  |  | 297,194,000 |  |  |  |  | $ 392,000 |  |
Gain (Loss) on Sale |  |  |  |  | 0 | 0 |  | $ (35,000) | 8,411,000 |  |  |  |  |  |
Scenario Plan [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Increase in operating expenses |  |  |  |  |  |  |  |  |  | $ 3,600,000 |  |  |  |  |
Scenario Plan [Member] | Land Lease Arrangements |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Increase in operating expenses |  |  |  |  |  |  |  |  |  | $ 800,000 |  |  |  |  |
Subaru Build-to-Service Center Project [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Rentable Square Feet | ft² |  |  |  | 83,000 |  |  |  |  |  |  |  |  |  |  |
Lease terms |  |  |  | 18 years |  |  |  |  |  |  |  |  |  |  |
Purchase option of lease from inception period | 5 years |  |  | 5 years |  |  |  |  |  |  |  |  |  |  |
Sales-type lease, interest income |  |  |  |  | $ 400,000 |  |  |  |  |  |  |  |  |  |
Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of developed parcels of land (in acres) | a |  |  | 34.6 |  |  |  |  |  |  |  |  |  |  |  |
Gross purchase value of assets |  |  | $ 20,600,000 |  |  |  |  |  |  |  |  |  |  |  |
Number of Parcels | Parcel |  |  |  |  | 3 |  |  | 3 |  |  |  |  |  |  |
Parcel One [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of land sold | a |  |  |  |  |  |  |  |  |  |  |  |  |  | 8.4 |
Parcel Two [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of land sold | a |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1.7
Parcel Three [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of land sold | a |  |  |  |  |  |  |  |  |  |  |  | 6.6 |  |  |
Garza Land Sale [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of developed parcels of land (in acres) | a |  |  | 34.6 |  |  |  |  |  |  |  |  |  |  |  |
Gross purchase value of assets |  |  | $ 20,600,000 |  |  |  |  |  |  |  |  |  |  |  |
Number of Parcels | Parcel |  |  |  |  | 3 |  |  | 3 |  |  |  |  |  |  |
Aggregate deferred gain recognized |  |  |  |  | $ 0 |  |  | $ 0 |  |  | $ 2,800,000 |  |  |  |
Garza Land Sale [Member] | Parcel One [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of land sold | a |  |  |  |  | 8.4 |  |  | 8.4 |  |  |  |  |  |  |
Garza Land Sale [Member] | Parcel One [Member] | Garza Land Acquisition [Member] | Third Party Developers [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Date of parcels sold |  |  |  |  |  |  |  | Jan. 30, 2017 |  |  |  |  |  |  |
Garza Land Sale [Member] | Parcel Two [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of land sold | a |  |  |  |  | 1.7 |  |  | 1.7 |  |  |  |  |  |  |
Garza Land Sale [Member] | Parcel Two [Member] | Garza Land Acquisition [Member] | Third Party Developers [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Date of parcels sold |  |  |  |  |  |  |  | Apr. 28, 2017 |  |  |  |  |  |  |
Garza Land Sale [Member] | Parcel Three [Member] | Garza Land Acquisition [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Area of land sold | a |  |  |  |  | 6.6 |  |  | 6.6 |  |  |  |  |  |  |
Garza Land Sale [Member] | Parcel Three [Member] | Garza Land Acquisition [Member] | Third Party [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Date of parcels sold |  |  |  |  |  |  |  | Mar. 16, 2018 |  |  |  |  |  |  |
Philadelphia Marine Center (Marine Piers) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Aggregate deferred gain recognized |  | $ 9,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Rentable Square Feet | ft² |  | 181,900 |  |  |  |  |  |  |  |  |  |  |  |  |
Sales Price |  | $ 21,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Payment by cash on purchases |  | 12,000,000.0 |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from the sale of properties |  | 11,200,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Balance payment on purchases |  | $ 9,400,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Date of second installment payment |  | Jan. 31, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |
Assets held for sale, net |  | $ 4,700,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Gain (Loss) on Sale |  | $ 6,500,000 |  |  |  |  |  |  |  |  |  |  |  |  |
ASU 2016-18 [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Restricted cash |  |  |  |  | $ 800,000 | 1,300,000 |  | $ 800,000 | 1,300,000 |  |  |  |  |  |
Increase in operating cash flows |  |  |  |  |  |  |  |  | 600,000 |  |  |  |  |  |
General and Administrative Expenses [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Income tax provision |  |  |  |  |  | 800,000 |  |  | 1,000,000.0 |  |  |  |  |  |
Net Income Tax Provision [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Reclassification of net income tax provision out of general and administrative expenses into net income tax provision |  |  |  |  |  | $ 800,000 |  |  | $ 1,000,000.0 |  |  |  |  |  |
Impairment Charges [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Basis Of Presentation [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Out-of-period error immaterial in current year |  |  |  |  |  |  | $ 1,200,000 |  |  |  |  |  |  |  |

X
- Definition Area of land acquired. + References No definition available. + Details
Name: | bdn_AreaOfLandAcquired
Namespace Prefix: | bdn_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Area of land sold + References No definition available. + Details
Name: | bdn_AreaOfLandSold
Namespace Prefix: | bdn_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | instant

X
- Definition Basis of presentation. + References No definition available. + Details
Name: | bdn_BasisOfPresentationLineItems
Namespace Prefix: | bdn_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date of parcels sold. + References No definition available. + Details
Name: | bdn_DateOfParcelsSold
Namespace Prefix: | bdn_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Date of second installment payment. + References No definition available. + Details
Name: | bdn_DateOfSecondInstallmentPayment
Namespace Prefix: | bdn_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of parcels sold. + References No definition available. + Details
Name: | bdn_NumberOfParcelsSold
Namespace Prefix: | bdn_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Payments to acquire real estate gross. + References No definition available. + Details
Name: | bdn_PaymentsToAcquireRealEstateGross
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Prior period error immaterial in current year financial statements. + References No definition available. + Details
Name: | bdn_PriorPeriodErrorImmaterialInCurrentYearFinancialStatements
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Purchase option of lease from inception period. + References No definition available. + Details
Name: | bdn_PurchaseOptionOfLeaseFromInceptionPeriod
Namespace Prefix: | bdn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Third party management contracts assets outstanding. + References No definition available. + Details
Name: | bdn_ThirdPartyManagementContractsAssetsOutstanding
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Third party management contracts liabilities outstanding. + References No definition available. + Details
Name: | bdn_ThirdPartyManagementContractsLiabilitiesOutstanding
Namespace Prefix: | bdn_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount classified as assets attributable to disposal group held for sale or disposed of. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=109222160&loc=d3e1107-107759 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5B -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721673-107760 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=109222160&loc=SL51721533-107759 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 50 -Paragraph 5C -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=109222650&loc=SL51721675-107760 + Details
Name: | us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date. + References No definition available. + Details
Name: | us-gaap_DeferredGainOnSaleOfProperty
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of consideration received or receivable for the disposal of assets and liabilities, including discontinued operation. + References No definition available. + Details
Name: | us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2443-110228 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230 + Details
Name: | us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount or range of possible amounts of gain that could be realized upon the resolution of a contingency. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 30 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6397426&loc=d3e17499-108355 + Details
Name: | us-gaap_GainContingencyUnrecordedAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 22 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 20 -Section 45 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109238882&loc=d3e38679-109324 + Details
Name: | us-gaap_IncomeTaxExpenseBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of increase (decrease) in operating assets classified as other. + 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 (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_IncreaseDecreaseInOtherOperatingAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Term of lessee's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980 + Details
Name: | us-gaap_LesseeOperatingLeaseTermOfContract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
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 Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantification
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase. + 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=109223946&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount of a reclassification adjustment made to prior period financial statement amounts. + References No definition available. + Details
Name: | us-gaap_PriorPeriodReclassificationAdjustment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of cash restricted as to withdrawal or usage. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=98513485&loc=SL98516268-108586 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03(1)(a)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(2)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_RestrictedCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of interest income from net investment in sales-type lease. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 5 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919372-209981 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 270 -SubTopic 10 -Section 50 -Paragraph 6A -URI http://asc.fasb.org/extlink&oid=109225645&loc=SL77927221-108306 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 25 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82918700&loc=SL77919101-209958 + Details
Name: | us-gaap_SalesTypeLeaseInterestIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of variable lease payments from operating, direct financing, and sales-type leases, excluding amount included in measurement of lease receivable. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 842 -SubTopic 30 -Section 50 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919372-209981 + Details
Name: | us-gaap_VariableLeaseIncome
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementScenarioAxis=us-gaap_ScenarioPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_LeaseArrangementTypeAxis=bdn_LandLeaseArrangementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=bdn_SubaruBuildToServiceCenterProjectMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

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

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

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

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=bdn_GarzaLandSaleMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=bdn_ThirdPartyDevelopersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=bdn_ThirdPartyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=bdn_PhiladelphiaMarineCenterMarinePiersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201618Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=us-gaap_GeneralAndAdministrativeExpenseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=bdn_IncomeTaxExpenseBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_QuantifyingMisstatementInCurrentYearFinancialStatementsByNatureOfErrorAxis=bdn_ImpairmentChargesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |