XML 56 R59.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Fair Value of Financial Instruments Fair Value of Financial Instruments (Details Textuals) (Details) | Mar. 31, 2013
--- | ---
Fair Value Disclosures [Abstract] |
Weighted Average Fair Value Interest Rate on Debt | 3.199%

X
- Definition Weighted Average Fair Value Interest Rate on Debt Unobservable Input Fair Value Intererest Rates + References No definition available. + Details
Name: | bdn_WeightedAverageFairValueInterestRateOnDebt
Namespace Prefix: | bdn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_FairValueDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration