Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Accounts receivable, allowance	$ 2,304	$ 1,736
Accrued rent receivable, allowance	13,009	14,442
Deferred costs, accumulated amortization	$ 58,769	$ 67,899
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Dividend Rate, Percentage	6.90%	6.90%
Preferred Stock, Par or Stated Value Per Share (USD per share)	$ 0.01	$ 0.01
Preferred Stock, Shares Issued	4,000,000	4,000,000
Preferred Stock, Shares Outstanding	4,000,000	4,000,000
Common Stock, Par or Stated Value Per Share (USD per share)	$ 0.01	$ 0.01
Common Stock, Shares Authorized	400,000,000	400,000,000
Common Stock, Shares, Issued	175,140,760	174,688,568
Common Stock, Shares, Outstanding	175,140,760	174,688,568
Common Shares in Grantor Trust	899,457	745,686
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Accounts receivable, allowance	$ 2,304	$ 1,736
Accrued rent receivable, allowance	13,009	14,442
Deferred costs, accumulated amortization	$ 58,769	$ 67,899
Preferred Stock, Dividend Rate, Percentage	6.90%	6.90%
Preferred Stock, Shares Issued	4,000,000	4,000,000
Preferred Stock, Shares Outstanding	4,000,000	4,000,000
Redeemable Limited Partnership Units Issued	1,479,799	1,535,102
Redeemable Limited Partnership Units Outstanding	1,479,799	1,535,102
General Partners' Capital Account, Units Issued	175,140,760	174,688,568
General Partners' Capital Account, Units Outstanding	175,140,760	174,688,568