XML 52 R51.htm IDEA: XBRL DOCUMENT  v2.3.0.11

Real Estate Investments (Details Textuals 1) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Jul. 29, 2011 sqft	Jun. 27, 2011 Three Greentree Center [Member] sqft
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net rentable square feet of properties sold		347,620	69,300
Sales price of properties sold		$ 86.7	$ 5.9
Lease percentage of sold property			13.90%
Gain on sale of ownership interest	$ 2.8
Remaining Ownership Interest in Real Estate Properties	11.00%
Number of properties with ownership interest	3

X

- Definition

Lease percentage of sold property.

+ Details

Name:	bdn_LeasePercentageOfSoldProperty
Namespace Prefix:	bdn
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Net Rentable Space Sold.

+ Details

Name:	bdn_NetRentableSpaceSold
Namespace Prefix:	bdn
Data Type:	us-types:areaItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Number of Real Estate Properties.

+ Details

Name:	bdn_NumberOfRealEstateProperties
Namespace Prefix:	bdn
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Realized Gains Losses on Sales of Investment Real Estate.

+ Details

Name:	bdn_RealizedGainsLossesOnSalesOfInvestmentRealEstate
Namespace Prefix:	bdn
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Definition

Remaining Ownership Interest in Real Estate Properties.

+ Details

Name:	bdn_RemainingOwnershipInterestInRealEstateProperties
Namespace Prefix:	bdn
Data Type:	us-types:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Sale Consideration Of Sold Property.

+ Details

Name:	bdn_SaleConsiderationOfSoldProperty
Namespace Prefix:	bdn
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

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.

+ Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration