Summary of Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information [Line Items]
Total revenue	$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 525,463	$ 602,631	$ 596,982
Net income (loss)	(12,370)	7,884	(1,323)	46,310	(62,700)	20,308	3,058	8,594	40,501	(30,740)	6,942
Net income (loss) allocated to Common Shares/ Partnership Unitholders	$ (14,058)	$ 6,022	$ (3,105)	$ 44,091	$ (63,941)	$ 18,346	$ 1,255	$ 6,710	$ 40,191	$ (30,401)	$ 6,975
Basic earnings (loss) per Common Shares/Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ 0.19	$ (0.21)	$ 0
Diluted earnings (loss) per Common Share/ Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ 0.19	$ (0.21)	$ 0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Quarterly Financial Information [Line Items]
Total revenue	$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 525,463	$ 602,631	$ 596,982
Net income (loss)	(12,370)	7,884	(1,323)	46,310	(62,700)	20,308	3,058	8,594	40,501	(30,740)	6,942
Net income (loss) allocated to Common Shares/ Partnership Unitholders	$ (14,176)	$ 6,074	$ (3,131)	$ 44,478	$ (64,502)	$ 18,506	$ 1,262	$ 6,768	$ 40,486	$ (30,737)	$ 6,986
Basic earnings (loss) per Common Shares/Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.36)	$ 0.10	$ 0.04	$ 0.04	$ 0.19	$ (0.21)	$ 0
Diluted earnings (loss) per Common Share/ Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.36)	$ 0.10	$ 0.04	$ 0.04	$ 0.19	$ (0.21)	$ 0