Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net income	$ 307,326	$ 34,529	$ 135,472
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	188,283	210,005	176,000
Amortization of deferred financing costs	2,904	2,768	2,498
Amortization of debt discount/(premium), net	(568)	189	702
Amortization of stock compensation costs	6,627	6,876	5,716
Straight-line rent income	(14,743)	(11,369)	(12,283)
Amortization of acquired above (below) market leases, net	(4,867)	(8,857)	(3,344)
Ground rent expense	1,455	1,470	431
Provision for doubtful accounts	1,049	(1,345)	1,775
Net gain on real estate venture transactions	(75)	(11,639)	(142,233)
Gain on promoted interest in unconsolidated real estate venture	0	0	(28,283)
Net gain on sale of interests in real estate	(289,662)	(2,376)	(5,972)
Loss on early extinguishment of debt	0	0	105
Provision for impairment	0	0	71,707
Other than temporary impairment	0	0	4,076
Loss from Real Estate Ventures, net of distributions	18,584	10,242	12,871
Income tax provision (benefit)	(224)	12	423
Changes in assets and liabilities:
Accounts receivable	(2,031)	(248)	3,524
Other assets	(5,034)	9,368	(14,334)
Accounts payable and accrued expenses	14,374	(5,599)	12,579
Deferred income, gains and rent	(12,149)	9,319	3,017
Other liabilities	14,557	(9,115)	2,902
Net cash provided by operating activities	225,806	234,230	227,349
Cash flows from investing activities:
Acquisition of properties	(41,950)	0	(196,625)
Acquisition of partners interest in consolidated real estate venture	0	(2,181)	0
Proceeds from the sale of properties	278,114	41,795	324,090
Proceeds from real estate venture sales	0	9,730	60,346
Issuance of note receivable	(50,000)	0	0
Issuance of mortgage note receivable	0	0	(175,172)
Proceeds from repayment of mortgage notes receivable	0	3,341	192
Proceeds from repayment of a capital lease	0	0	181
Capital expenditures for tenant improvements	(73,166)	(67,258)	(65,264)
Capital expenditures for redevelopments	(21,664)	(53,846)	(48,231)
Capital expenditures for developments	(65,420)	(77,192)	(99,104)
Advances for the purchase of tenant assets, net of repayments	1,488	(1,035)	410
Investment in unconsolidated Real Estate Ventures	(719)	(253)	(908)
Deposits for real estate	0	(4,181)	(8,234)
Escrowed cash	0	0	5,694
Capital distributions from Real Estate Ventures	9,001	35,906	6,526
Leasing costs paid	(17,394)	(15,485)	(18,407)
Net cash provided by (used in) investing activities	18,290	(130,659)	(214,506)
Cash flows from financing activities:
Repayments of mortgage notes payable	(94,993)	(7,595)	(122,180)
Proceeds from credit facility borrowings	318,000	348,500	455,500
Repayments of credit facility borrowings	(318,000)	(441,000)	(363,000)
Proceeds from unsecured notes	0	216,373	0
Debt financing costs paid	0	(1,965)	(3,430)
Proceeds from the exercise of stock options	47	3,771	0
Proceeds from the issuance of common shares	0	0	416
Shares used for employee taxes upon vesting of share awards	(1,346)	(1,554)	(1,494)
Partner contributions to consolidated real estate venture	0	27	16
Partner distributions from consolidated real estate venture	0	0	(94)
Repurchase and retirement of common shares	(60,000)	(17,282)	(21,841)
Redemption of limited partnership units	0	0	(7,043)
Distributions paid to shareholders	(131,150)	(134,140)	(128,859)
Distributions to noncontrolling interest	(747)	(747)	(1,065)
Net cash used in financing activities	(288,189)	(35,612)	(193,074)
Increase/(Decrease) in cash and cash equivalents and restricted cash	(44,093)	67,959	(180,231)
Cash and cash equivalents, beginning of period	90,499	22,842	202,179
Restricted cash, beginning of period	671	369	1,263
Cash and cash equivalents and restricted cash at beginning of year	91,170	23,211	203,442
Cash and cash equivalents, end of period	46,344	90,499	22,842
Restricted cash, end of period	733	671	369
Cash and cash equivalents and restricted cash at end of period	47,077	91,170	23,211
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2020, 2019 and 2018 of $4,650, $2,246 and $3,586 respectively	79,498	66,508	76,858
Cash paid for income taxes	688	1,385	405
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	32,706	33,815	33,632
Change in construction-in-progress related to non-cash disposition of land	0	0	27,231
Change in deferred income, gains and rent to the non-cash disposition of land	0	0	(29,780)
Change in investment in real estate ventures as a result of dispositions	0	1,806	14,169
Change in Notes receivable as a result of a noncash acquisition of an operating property	0	0	130,742
Change in real estate ventures as a result of other than temporary impairment	0	0	(4,076)
Change in operating real estate related to a non-cash acquisition of an operating property	0	0	(20,653)
Change in intangible assets, net related to non-cash acquisition of an operating property	0	0	(3,144)
Change in acquired lease intangibles, net related to non-cash acquisition of an operating property	0	0	182
Change in investments in joint venture related to non-cash acquisition of property	0	0	(16,832)
Change in mortgage notes payable related to acquisition of an operating property	0	0	9,940
Change in operating real estate from deconsolidation of operating properties	(427,710)	0	0
Change in investment in real estate ventures from deconsolidation of operating properties	(296,262)	0	0
Change in mortgage notes payable from deconsolidation of operating properties	(220,271)	0	0
Change in capital expenditures financed through accounts payable at period end	(9,949)	(10,618)	8,784
Change in other assets as a result of deconsolidation of operating properties	1,471	0	0
Change in capital expenditures financed through retention payable at period end	284	(946)	(2,912)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income	307,326	34,529	135,472
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	188,283	210,005	176,000
Amortization of deferred financing costs	2,904	2,768	2,498
Amortization of debt discount/(premium), net	(568)	189	702
Amortization of stock compensation costs	6,627	6,876	5,716
Straight-line rent income	(14,743)	(11,369)	(12,283)
Amortization of acquired above (below) market leases, net	(4,867)	(8,857)	(3,344)
Ground rent expense	1,455	1,470	431
Provision for doubtful accounts	1,049	(1,345)	1,775
Net gain on real estate venture transactions	(75)	(11,639)	(142,233)
Gain on promoted interest in unconsolidated real estate venture	0	0	(28,283)
Net gain on sale of interests in real estate	(289,662)	(2,376)	(5,972)
Loss on early extinguishment of debt	0	0	105
Provision for impairment	0	0	71,707
Other than temporary impairment	0	0	4,076
Loss from Real Estate Ventures, net of distributions	18,584	10,242	12,871
Income tax provision (benefit)	(224)	12	423
Changes in assets and liabilities:
Accounts receivable	(2,031)	(248)	3,524
Other assets	(5,034)	9,368	(14,334)
Accounts payable and accrued expenses	14,374	(5,599)	12,579
Deferred income, gains and rent	(12,149)	9,319	3,017
Other liabilities	14,557	(9,115)	2,902
Net cash provided by operating activities	225,806	234,230	227,349
Cash flows from investing activities:
Acquisition of properties	(41,950)	0	(196,625)
Acquisition of partners interest in consolidated real estate venture	0	(2,181)	0
Proceeds from the sale of properties	278,114	41,795	324,090
Proceeds from real estate venture sales	0	9,730	60,346
Issuance of note receivable	(50,000)	0	0
Issuance of mortgage note receivable	0	0	(175,172)
Proceeds from repayment of mortgage notes receivable	0	3,341	192
Proceeds from repayment of a capital lease	0	0	181
Capital expenditures for tenant improvements	(73,166)	(67,258)	(65,264)
Capital expenditures for redevelopments	(21,664)	(53,846)	(48,231)
Capital expenditures for developments	(65,420)	(77,192)	(99,104)
Advances for the purchase of tenant assets, net of repayments	1,488	(1,035)	410
Investment in unconsolidated Real Estate Ventures	(719)	(253)	(908)
Deposits for real estate	0	(4,181)	(8,234)
Escrowed cash	0	0	5,694
Capital distributions from Real Estate Ventures	9,001	35,906	6,526
Leasing costs paid	(17,394)	(15,485)	(18,407)
Net cash provided by (used in) investing activities	18,290	(130,659)	(214,506)
Cash flows from financing activities:
Repayments of mortgage notes payable	(94,993)	(7,595)	(122,180)
Proceeds from credit facility borrowings	318,000	348,500	455,500
Repayments of credit facility borrowings	(318,000)	(441,000)	(363,000)
Proceeds from unsecured notes	0	216,373	0
Debt financing costs paid	0	(1,965)	(3,430)
Proceeds from the exercise of stock options	47	3,771	0
Proceeds from the issuance of common shares	0	0	416
Shares used for employee taxes upon vesting of share awards	(1,346)	(1,554)	(1,494)
Partner contributions to consolidated real estate venture	0	27	16
Partner distributions from consolidated real estate venture	0	0	(94)
Repurchase and retirement of common shares	(60,000)	(17,282)	(21,841)
Redemption of limited partnership units	0	0	(7,043)
Distributions paid to shareholders	(131,897)	(134,887)	(129,924)
Net cash used in financing activities	(288,189)	(35,612)	(193,074)
Increase/(Decrease) in cash and cash equivalents and restricted cash	(44,093)	67,959	(180,231)
Cash and cash equivalents, beginning of period	90,499	22,842	202,179
Restricted cash, beginning of period	671	369	1,263
Cash and cash equivalents and restricted cash at beginning of year	91,170	23,211	203,442
Cash and cash equivalents, end of period	46,344	90,499	22,842
Restricted cash, end of period	733	671	369
Cash and cash equivalents and restricted cash at end of period	47,077	91,170	23,211
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2020, 2019 and 2018 of $4,650, $2,246 and $3,586 respectively	79,498	66,508	76,858
Cash paid for income taxes	688	1,385	405
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	32,706	33,815	33,632
Change in construction-in-progress related to non-cash disposition of land	0	0	27,231
Change in deferred income, gains and rent to the non-cash disposition of land	0	0	(29,780)
Change in investment in real estate ventures as a result of dispositions	0	1,806	14,169
Change in Notes receivable as a result of a noncash acquisition of an operating property	0	0	130,742
Change in real estate ventures as a result of other than temporary impairment	0	0	(4,076)
Change in operating real estate related to a non-cash acquisition of an operating property	0	0
Change in intangible assets, net related to non-cash acquisition of an operating property	0	0	(3,144)
Change in acquired lease intangibles, net related to non-cash acquisition of an operating property	0	0	182
Change in investments in joint venture related to non-cash acquisition of property	0	0	(16,832)
Change in mortgage notes payable related to acquisition of an operating property	0	0	9,940
Change in operating real estate from deconsolidation of operating properties			(20,653)
Change in capital expenditures financed through accounts payable at period end	(9,949)	(10,618)	8,784
Change in other assets as a result of deconsolidation of operating properties	1,471	0	0
Change in capital expenditures financed through retention payable at period end	$ 284	$ (946)	$ (2,912)