Beneficiaries Equity of the Parent Company (Details Textuals) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		12 Months Ended	0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Apr. 15, 2015	Nov. 05, 2013	Apr. 06, 2015	Mar. 11, 2015
Class of Stock [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	1,535,102	1,763,739
Distributions payable	$ 29,038		$ 28,871
Preferred Stock, Dividend Rate, Percentage	6.90%		6.90%
Dividends, Preferred Stock, Cash	1,725	1,725
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage	6.90%
Preferred Stock, Liquidation Preference Per Share	$ 25.00
Offering Program [Member]
Class of Stock [Line Items]
Shares Authorized For Equity Offering Program					16,000,000
Remaining Shares Available For Sales	16,000,000
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Distributions payable	29,038		28,871
Preferred Stock, Dividend Rate, Percentage	6.90%		6.90%
Dividend Paid [Member] | Subsequent Event [Member]
Class of Stock [Line Items]
Distributions payable						27,300
Dividend Paid [Member] | Subsequent Event [Member] | Series E Preferred Stock [Member]
Class of Stock [Line Items]
Dividends, Preferred Stock, Cash				1,700
Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P. | Subsequent Event [Member]
Class of Stock [Line Items]
Distributions payable						$ 27,300
Dividend Declared [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Dividends Payable, Amount Per Share							$ 0.15
Maximum [Member]
Class of Stock [Line Items]
Fees and Commissions Percentage	2.00%