Debt Instrument, Covenant, Interest Coverage Ratio, Minimum

No definition available.

Name:	bdn_DebtInstrumentCovenantInterestCoverageRatioMinimum
Namespace Prefix:	bdn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Leverage Ratio, Maximum

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentCovenantLeverageRatioMaximum
Namespace Prefix:	bdn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Liquidity Ratio Required, Minimum

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentCovenantLiquidityRatioRequiredMinimum
Namespace Prefix:	bdn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Maximum Percent Of Payments Of Dividends And Distributions

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentCovenantMaximumPercentOfPaymentsOfDividendsAndDistributions
Namespace Prefix:	bdn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Maximum Secured Indebtedness To Asset Value Ratio

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentCovenantMaximumSecuredIndebtednessToAssetValueRatio
Namespace Prefix:	bdn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Covenant, Maximum Unsecured Indebtedness To Unencumbered Asset Value Ratio

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentCovenantMaximumUnsecuredIndebtednessToUnencumberedAssetValueRatio
Namespace Prefix:	bdn_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument, Extension Term

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentExtensionTerm
Namespace Prefix:	bdn_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Debt Instrument Number Of Extensions

+ References

No definition available.

+ Details

Name:	bdn_DebtInstrumentNumberOfExtensions
Namespace Prefix:	bdn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

Name:	bdn_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	bdn_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI https://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: 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(16))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

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(22))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI https://asc.fasb.org/extlink&oid=126897435&loc=d3e534808-122878

+ Details

Name:	us-gaap_DebtInstrumentCarryingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- 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_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

+ Details

Name:	us-gaap_DeferredFinanceCostsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Aggregate amount of interest expense on all borrowings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.7,8)
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

Name:	us-gaap_InterestExpenseBorrowings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=bdn_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrOvernightIndexSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LetterOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=bdn_A2022CreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

DEBT OBLIGATIONS - Narrative (Details)		9 Months Ended
DEBT OBLIGATIONS - Narrative (Details)	Jun. 30, 2022 USD ($) property	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Principal balance outstanding		$ 2,074,610,000
Letters of credit outstanding		4,300,000
Line of Credit \| Term loan
Debt Instrument [Line Items]
Capitalized financing costs	$ 2,000,000
Unsecured Debt
Debt Instrument [Line Items]
Principal balance outstanding		2,074,610,000	$ 1,851,610,000
Unsecured Debt \| Term loan
Debt Instrument [Line Items]
Principal balance outstanding	$ 250,000,000	$ 250,000,000	$ 250,000,000
Spread on variable rate		1.20%
Unsecured Debt \| Term loan \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Spread on variable rate	1.20%
Unsecured Debt \| Term loan \| Minimum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Spread on variable rate	0.80%
Unsecured Debt \| Term loan \| Minimum \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate	0.00%
Unsecured Debt \| Term loan \| Maximum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Spread on variable rate	1.60%
Unsecured Debt \| Term loan \| Maximum \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate	0.60%
Letter of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity (up to)	$ 50,000,000
Revolving Credit Facility \| Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity (up to)	600,000,000
Capitalized financing costs	4,700,000
Line of credit facility, accordion feature	$ 500,000,000
Spread on variable rate	0.25%
Weighted average interest rate		2.41%
Interest expense		$ 3,200,000
Available borrowings under its unsecured credit facility		$ 349,700,000
Revolving Credit Facility \| Line of Credit \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Spread on variable rate	1.05%
Revolving Credit Facility \| Line of Credit \| Minimum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Spread on variable rate	0.725%
Revolving Credit Facility \| Line of Credit \| Minimum \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate	0.00%
Revolving Credit Facility \| Line of Credit \| Maximum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Spread on variable rate	1.40%
Revolving Credit Facility \| Line of Credit \| Maximum \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate	0.40%
Revolving Credit Facility \| Line of Credit \| 2022 Credit Facility
Debt Instrument [Line Items]
Maturity period \| property	2
Extension term	6 months
Line of credit facility covenant minimum fixed charge coverage ratio	1.5
Line of credit facility covenant maximum leverage ratio	0.60
Line of credit facility covenant maximum unsecured indebtedness to unencumbered asset value ratio	0.60
Line of credit facility covenant maximum secured indebtedness to asset value ratio	0.40
Line of credit facility covenant minimum unencumbered cash flow to interest expense on unsecured debt ratio	1.75
Line of credit facility covenant maximum percent of payments of dividends and distributions	0.95