Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue
Total revenue	$ 544,345	$ 520,493	$ 525,463
Operating expenses:
Property operating expenses	154,772	150,835	152,926
Real estate taxes	51,341	45,204	46,252
Third party management expenses	11,910	9,960	10,270
Depreciation and amortization	174,259	179,357	189,676
General and administrative expenses	27,802	28,538	26,596
Provision for impairment	71,707	3,057	40,517
Total operating expenses	491,791	416,951	466,237
Gain on sale of real estate
Net gain on disposition of real estate	2,932	31,657	116,983
Net gain on sale of undepreciated real estate	3,040	953	9,232
Total gain on sale of real estate	5,972	32,610	126,215
Operating income	58,526	136,152	185,441
Other income (expense):
Interest income	4,703	1,113	1,236
Interest expense	(78,199)	(81,886)	(84,708)
Interest expense - amortization of deferred financing costs	(2,498)	(2,435)	(2,696)
Interest expense - financing obligation	0	0	(679)
Equity in loss of Real Estate Ventures	(15,231)	(8,306)	(11,503)
Net gain on real estate venture transactions	142,233	80,526	20,000
Gain on promoted interest in unconsolidated real estate venture	28,283	0	0
Loss on early extinguishment of debt	(105)	(3,933)	(66,590)
Net income before income taxes	137,712	121,231	40,501
Income tax (provision) benefit	(423)	628	0
Net income	137,289	121,859	40,501
Net income attributable to noncontrolling interests	(965)	(1,009)	(310)
Net income attributable to Brandywine Realty Trust	136,324	120,850	40,191
Distribution to preferred shareholders	0	(2,032)	(6,900)
Preferred share redemption charge	0	(3,181)	0
Nonforfeitable dividends allocated to unvested restricted shareholders	(369)	(327)	(341)
Net income attributable to Common Shareholders of Brandywine Realty Trust	$ 135,955	$ 115,310	$ 32,950
Basic income per Common Share	$ 0.76	$ 0.66	$ 0.19
Diluted income per Common Share	$ 0.76	$ 0.65	$ 0.19
Basic weighted average shares outstanding	178,519,748	175,484,350	175,018,163
Diluted weighted average shares outstanding	179,641,492	176,808,166	176,010,814
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Total revenue	$ 544,345	$ 520,493	$ 525,463
Operating expenses:
Property operating expenses	154,772	150,835	152,926
Real estate taxes	51,341	45,204	46,252
Third party management expenses	11,910	9,960	10,270
Depreciation and amortization	174,259	179,357	189,676
General and administrative expenses	27,802	28,538	26,596
Provision for impairment	71,707	3,057	40,517
Total operating expenses	491,791	416,951	466,237
Gain on sale of real estate
Net gain on disposition of real estate	2,932	31,657	116,983
Net gain on sale of undepreciated real estate	3,040	953	9,232
Total gain on sale of real estate	5,972	32,610	126,215
Operating income	58,526	136,152	185,441
Other income (expense):
Interest income	4,703	1,113	1,236
Interest expense	(78,199)	(81,886)	(84,708)
Interest expense - amortization of deferred financing costs	(2,498)	(2,435)	(2,696)
Interest expense - financing obligation	0	0	(679)
Equity in loss of Real Estate Ventures	(15,231)	(8,306)	(11,503)
Net gain on real estate venture transactions	142,233	80,526	20,000
Gain on promoted interest in unconsolidated real estate venture	28,283	0	0
Loss on early extinguishment of debt	(105)	(3,933)	(66,590)
Net income before income taxes	137,712	121,231	40,501
Income tax (provision) benefit	(423)	628	0
Net income	137,289	121,859	40,501
Net income attributable to noncontrolling interests - consolidated real estate ventures	(55)	(29)	(15)
Distribution to preferred shareholders	0	(2,032)	(6,900)
Preferred share redemption charge	0	(3,181)	0
Nonforfeitable dividends allocated to unvested restricted shareholders	(369)	(327)	(341)
Net income attributable to Common Shareholders of Brandywine Realty Trust	136,865	116,290	33,245
Net income attributable to Brandywine Operating Partnership	137,234	121,830	40,486
Distribution to preferred unitholders	0	(2,032)	(6,900)
Preferred unit redemption charge	0	(3,181)	0
Nonforfeitable dividends allocated to unvested restricted unitholders	$ (369)	$ (327)	$ (341)
Basic income per Common Share	$ 0.76	$ 0.66	$ 0.19
Diluted income per Common Share	$ 0.76	$ 0.65	$ 0.19
Basic weighted average shares outstanding	179,959,370	176,964,149	176,523,800
Diluted weighted average shares outstanding	181,081,114	178,287,965	177,516,451
Rents [Member]
Revenue
Lease revenue	$ 430,656	$ 412,333	$ 421,505
Rents [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Lease revenue	430,656	412,333	421,505
Tenant Reimbursements [Member]
Revenue
Service and other revenue	82,625	72,620	70,629
Tenant Reimbursements [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Service and other revenue	82,625	72,620	70,629
Termination Fees [Member]
Revenue
Lease revenue	1,763	2,370	2,339
Termination Fees [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Lease revenue	1,763	2,370	2,339
Third Party Management Fees, Labor Reimbursement and Leasing [Member]
Revenue
Service and other revenue	22,557	28,345	26,674
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Service and other revenue	22,557	28,345	26,674
Other [Member]
Revenue
Service and other revenue	6,744	4,825	4,316
Other [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Service and other revenue	$ 6,744	$ 4,825	$ 4,316