CONSOLIDATED STATEMENTS OF PARTNERS’ EQUITY - USD ($) $ in Thousands	Total	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interest - Consolidated Real Estate Ventures	BRANDYWINE OPERATING PARTNERSHIP, L.P.	BRANDYWINE OPERATING PARTNERSHIP, L.P. Accumulated Other Comprehensive Income (Loss)	BRANDYWINE OPERATING PARTNERSHIP, L.P. Noncontrolling Interest - Consolidated Real Estate Ventures	BRANDYWINE OPERATING PARTNERSHIP, L.P. General Partner Capital
Beginning balance (in shares) at Dec. 31, 2020							170,572,964
Beginning Balance at Dec. 31, 2020				$ 1,793,082	$ (7,935)	$ 72	$ 1,800,945
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	$ 6,964		$ 43	6,964		(1)	$ 6,965
Other comprehensive income	1,098	$ 1,092	6	1,098	1,098
Deferred compensation obligation (in shares)							(18,058)
Deferred compensation obligation	(198)			(198)			$ (198)
Share-based compensation activity (in shares)							108,345
Share-based compensation activity	2,502			2,502			$ 2,502
Adjustment of redeemable partnership units to liquidation value at period end				(1,294)			(1,294)
Distributions declared to general partnership unit holders				(32,573)			$ (32,573)
Ending balance (in shares) at Mar. 31, 2021							170,663,251
Ending Balance at Mar. 31, 2021				1,769,581	(6,837)	71	$ 1,776,347
Beginning balance (in shares) at Dec. 31, 2020							170,572,964
Beginning Balance at Dec. 31, 2020				1,793,082	(7,935)	72	$ 1,800,945
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	7,763			7,763
Other comprehensive income	3,245			3,245
Ending balance (in shares) at Sep. 30, 2021							171,126,257
Ending Balance at Sep. 30, 2021				1,714,307	(4,690)	68	$ 1,718,929
Beginning balance (in shares) at Mar. 31, 2021							170,663,251
Beginning Balance at Mar. 31, 2021				1,769,581	(6,837)	71	$ 1,776,347
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(175)		(8)	(175)		(1)	(174)
Other comprehensive income	1,048	1,042	6	1,048	1,048
Deferred compensation obligation	0
Repurchase and retirement of LP units				(2,334)			(2,334)
Issuance of partnership interest in consolidated real estate ventures	2,289		2,289	2,289			$ 2,289
Share-based compensation activity (in shares)							237,240
Share-based compensation activity	690			690			$ 690
Adjustment of redeemable partnership units to liquidation value at period end				1,066			1,066
Distributions declared to general partnership unit holders				(32,562)			$ (32,562)
Ending balance (in shares) at Jun. 30, 2021							170,900,491
Ending Balance at Jun. 30, 2021				1,739,603	(5,789)	70	$ 1,745,322
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	974		7	974		(2)	$ 976
Other comprehensive income	1,099	1,094	5	1,099	1,099
Issuance of LP Units (in shares)							226,695
Issuance of LP Units	3,052						$ 3,052
Issuance of partnership interest in consolidated real estate ventures	476		476	476			$ 476
Share-based compensation activity (in shares)							(929)
Share-based compensation activity	1,585			1,585			$ 1,585
Adjustment of redeemable partnership units to liquidation value at period end				124			124
Distributions declared to general partnership unit holders				(32,606)			$ (32,606)
Ending balance (in shares) at Sep. 30, 2021							171,126,257
Ending Balance at Sep. 30, 2021				1,714,307	(4,690)	68	$ 1,718,929
Beginning balance (in shares) at Dec. 31, 2021							171,126,257
Beginning Balance at Dec. 31, 2021				1,690,079	(2,366)	2,834	$ 1,689,611
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	6,101		8	6,101		(2)	$ 6,103
Other comprehensive income	3,952	3,940	12	3,952	3,952
Deferred compensation obligation (in shares)							(19,406)
Deferred compensation obligation	(249)			(249)			$ (249)
Repurchase and retirement of LP units				(4,006)			$ (4,006)
Share-based compensation activity (in shares)							277,061
Share-based compensation activity	1,655			1,655			$ 1,655
Adjustment of redeemable partnership units to liquidation value at period end				3,704			3,704
Distributions declared to general partnership unit holders				(32,711)			$ (32,711)
Ending balance (in shares) at Mar. 31, 2022							171,383,912
Ending Balance at Mar. 31, 2022				1,668,525	1,586	2,832	$ 1,664,107
Beginning balance (in shares) at Dec. 31, 2021							171,126,257
Beginning Balance at Dec. 31, 2021				1,690,079	(2,366)	2,834	$ 1,689,611
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	24,230			24,230
Other comprehensive income	6,565			6,565
Ending balance (in shares) at Sep. 30, 2022							171,569,807
Ending Balance at Sep. 30, 2022				1,631,416	4,199	2,829	$ 1,624,388
Beginning balance (in shares) at Mar. 31, 2022							171,383,912
Beginning Balance at Mar. 31, 2022				1,668,525	1,586	2,832	$ 1,664,107
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	4,651		14	4,651		(2)	$ 4,653
Other comprehensive income	1,935	1,929	6	1,935	1,935
Deferred compensation obligation	0
Share-based compensation activity (in shares)							191,368
Share-based compensation activity	1,917			1,917			$ 1,917
Adjustment of redeemable partnership units to liquidation value at period end				2,181			2,181
Distributions declared to general partnership unit holders				(32,705)			$ (32,705)
Ending balance (in shares) at Jun. 30, 2022							171,575,280
Ending Balance at Jun. 30, 2022				1,646,504	3,521	2,830	$ 1,640,153
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	13,478		37	13,478		(1)	$ 13,479
Other comprehensive income	678	$ 676	$ 2	678	678
Deferred compensation obligation (in shares)							(6,573)
Deferred compensation obligation	(63)			(63)			$ (63)
Share-based compensation activity (in shares)							1,100
Share-based compensation activity	$ 2,094			2,094			$ 2,094
Adjustment of redeemable partnership units to liquidation value at period end				1,428			1,428
Distributions declared to general partnership unit holders				(32,703)			$ (32,703)
Ending balance (in shares) at Sep. 30, 2022							171,569,807
Ending Balance at Sep. 30, 2022				$ 1,631,416	$ 4,199	$ 2,829	$ 1,624,388