Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	$ (1,945)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges	0	0	125
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,079)	(1,945)
Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(1,945)	(9,138)	(17,005)
Change during year	(4,499)	7,320	7,395
Non-controlling interest consolidated - real estate venture partner's share of unrealized (gains)/losses on derivative financial statements	212	(155)	290
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,079)	(1,945)	(9,138)
Unrealized Gains (Losses) on Securities
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(9)	(9)	(9)
Change during year	0	0	0
Non-controlling interest consolidated - real estate venture partner's share of unrealized (gains)/losses on derivative financial statements	0	0	0
Ineffectiveness of the hedges			0
Other			0
Reclassification adjustment for (gains) losses reclassified to operations	0	0	0
Ending Balance	(9)	(9)	(9)
Cash Flow Hedges
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(1,936)	(9,129)	(16,996)
Change during year	(4,499)	7,320	7,395
Non-controlling interest consolidated - real estate venture partner's share of unrealized (gains)/losses on derivative financial statements	212	(155)	290
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,070)	(1,936)	(9,129)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	(2,080)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges	0	0	125
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	184
Ending Balance	(6,426)	(2,080)
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Accumulated Other Comprehensive Income (Loss)
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	2,080	(9,428)	(17,005)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	(184)
Ending Balance	(6,426)	2,080	(9,428)
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Unrealized Gains (Losses) on Securities
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	9	(9)	(9)
Change during year		0	0
Ineffectiveness of the hedges			0
Other			0
Reclassification adjustment for (gains) losses reclassified to operations	0	0	0
Ending Balance	(9)	9	(9)
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Cash Flow Hedges
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Beginning Balance	2,071	(9,419)	(16,996)
Change during year	(4,499)	7,320	7,395
Ineffectiveness of the hedges			(125)
Other			491
Reclassification adjustment for (gains) losses reclassified to operations	(153)	(28)	(184)
Ending Balance	$ (6,417)	$ 2,071	$ (9,419)