Brandywine Operating Partnership 10-Q 23 Oct 18 2018 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	9 Months Ended
	Sep. 30, 2018	Oct. 19, 2018
Document Information [Line Items]
Entity Registrant Name	BRANDYWINE REALTY TRUST
Trading Symbol	BDN
Entity Central Index Key	790,816
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false
Entity Common Stock, Shares Outstanding		178,602,602
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Document Information [Line Items]
Entity Registrant Name	BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Central Index Key	1,060,386
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Document Type	10-Q
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Real estate investments:
Operating properties		$ 3,429,048	$ 3,832,348
Accumulated depreciation		(845,674)	(895,091)
Operating real estate investments, net		2,583,374	2,937,257
Construction-in-progress		157,075	121,188
Land held for development	[1]	77,578	98,242
Prepaid leasehold interests in land held for development, net	[2]	40,100	0
Total real estate investments, net		2,858,127	3,156,687
Assets held for sale, net		297,194	392
Cash and cash equivalents		70,360	202,179
Accounts receivable, net of allowance of $3,782 and $3,467 as of September 30, 2018 and December 31, 2017, respectively		13,871	17,938
Accrued rent receivable, net of allowance of $13,562 and $13,645 as of September 30, 2018 and December 31, 2017, respectively		178,013	169,760
Investment in Real Estate Ventures, equity method		167,782	194,621
Deferred costs, net		97,004	96,695
Intangible assets, net		55,139	64,972
Other assets		186,132	92,204
Total assets		3,923,622	3,995,448
LIABILITIES AND EQUITY
Mortgage notes payable, net		322,588	317,216
Unsecured term loan, net		248,677	248,429
Unsecured senior notes, net		1,366,272	1,365,183
Accounts payable and accrued expenses		116,994	107,074
Distributions payable		32,492	32,456
Deferred income, gains and rent		26,731	42,593
Acquired lease intangibles, net		17,680	20,274
Liabilities related to assets held for sale		826	0
Other liabilities		14,559	15,623
Total liabilities		2,146,819	2,148,848
Commitments and contingencies
Equity:
Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 400,000,000; 178,602,602 and 178,285,236 issued and outstanding as of September 30, 2018 and December 31, 2017, respectively		1,787	1,784
Additional paid-in-capital		3,223,817	3,218,564
Deferred compensation payable in common shares		14,021	12,445
Common shares in grantor trust, 977,120 and 894,736 issued and outstanding as of September 30, 2018 and December 31, 2017, respectively		(14,021)	(12,445)
Cumulative earnings		674,599	660,174
Accumulated other comprehensive income		10,239	2,399
Cumulative distributions		(2,150,463)	(2,053,741)
Total Brandywine Realty Trust's equity		1,759,979	1,829,180
Noncontrolling interests		16,824	17,420
Total beneficiaries' equity		1,776,803	1,846,600
Total liabilities and beneficiaries' equity		3,923,622	3,995,448
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Operating properties		3,429,048	3,832,348
Accumulated depreciation		(845,674)	(895,091)
Operating real estate investments, net		2,583,374	2,937,257
Construction-in-progress		157,075	121,188
Land held for development		77,578	98,242
Prepaid leasehold interests in land held for development, net		40,100	0
Total real estate investments, net		2,858,127	3,156,687
Assets held for sale, net		297,194	392
Cash and cash equivalents		70,360	202,179
Accounts receivable, net of allowance of $3,782 and $3,467 as of September 30, 2018 and December 31, 2017, respectively		13,871	17,938
Accrued rent receivable, net of allowance of $13,562 and $13,645 as of September 30, 2018 and December 31, 2017, respectively		178,013	169,760
Investment in Real Estate Ventures, equity method		167,782	194,621
Deferred costs, net		97,004	96,695
Intangible assets, net		55,139	64,972
Other assets		186,132	92,204
Total assets		3,923,622	3,995,448
LIABILITIES AND EQUITY
Mortgage notes payable, net		322,588	317,216
Unsecured term loan, net		248,677	248,429
Unsecured senior notes, net		1,366,272	1,365,183
Accounts payable and accrued expenses		116,994	107,074
Distributions payable		32,492	32,456
Deferred income, gains and rent		26,731	42,593
Acquired lease intangibles, net		17,680	20,274
Liabilities related to assets held for sale		826	0
Other liabilities		14,559	15,623
Total liabilities		2,146,819	2,148,848
Commitments and contingencies
Redeemable limited partnership units at redemption value; 1,479,799 issued and outstanding as of September 30, 2018 and December 31, 2017		23,239	26,918
Equity:
General Partnership Capital; 178,602,602 and 178,285,236 issued and outstanding as of September 30, 2018 and December 31, 2017, respectively		1,741,379	1,815,411
Accumulated other comprehensive income		9,962	2,056
Total Brandywine Operating Partnership, L.P.'s equity		1,751,341	1,817,467
Non-controlling interest - consolidated real estate ventures		2,223	2,215
Total partners' equity		1,753,564	1,819,682
Total liabilities and beneficiaries' equity		$ 3,923,622	$ 3,995,448
[1]	As of September 30, 2018, the Company categorized 37.9 acres of land held for development, comprised of 2.7 acres and 35.2 acres, located in the Pennsylvania Suburbs segment and Other segment, respectively, as held for sale in accordance with applicable accounting standards for long lived assets. As of December 31, 2017, the Company categorized 13.1 acres of land held for development, located in the Other segment, as held for sale in accordance with applicable accounting standards for long lived assets.
[2]	As of September 30, 2018, this caption comprised leasehold interests in prepaid 99-year ground leases at 3025 and 3001-3003 JFK Boulevard, in Philadelphia, Pennsylvania. See Note 3, “Real Estate Investments,”

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts receivable, allowance	$ 3,782	$ 3,467
Accrued rent receivable, allowance	$ 13,562	$ 13,645
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	178,602,602	178,285,236
Common Stock, Shares, Outstanding	178,602,602	178,285,236
Common Shares in Grantor Trust, Issued	977,120	894,736
Common Shares in Grantor Trust, Outstanding	977,120	894,736
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Accounts receivable, allowance	$ 3,782	$ 3,467
Accrued rent receivable, allowance	$ 13,562	$ 13,645
Redeemable Limited Partnership Units Issued	1,479,799	1,479,799
Redeemable Limited Partnership Units Outstanding	1,479,799	1,479,799
General Partners' Capital Account, Units Issued	178,602,602	178,285,236
General Partners' Capital Account, Units Outstanding	178,602,602	178,285,236

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenue
Total revenue	$ 134,998	$ 128,438	$ 405,142	$ 387,149
Operating expenses
Property operating expenses	37,833	36,847	115,052	110,947
Real estate taxes	12,433	11,235	37,272	34,062
Third party management expenses	2,612	2,619	9,605	7,391
Depreciation and amortization	43,900	42,429	130,908	132,584
General and administrative expenses	5,963	5,813	22,209	21,797
Provision for impairment	56,865	0	56,865	3,057
Total operating expenses	159,606	98,943	371,911	309,838
Operating income (loss)	(24,608)	29,495	33,231	77,311
Other income (expense):
Interest income	1,220	79	2,564	635
Interest expense	(19,257)	(19,732)	(58,091)	(61,473)
Interest expense - amortization of deferred financing costs	(618)	(577)	(1,872)	(1,807)
Equity in income (loss) of Real Estate Ventures	1	(5,723)	(1,182)	(5,387)
Net gain (loss) on disposition of real estate	0	0	(35)	8,411
Net gain on sale of undepreciated real estate	0	953	2,859	953
Net gain on Real Estate Venture transactions	0	13,758	37,263	28,340
Net income (loss) before income taxes	(43,262)	18,253	14,737	46,983
Income tax (provision) benefit	0	793	(158)	1,032
Net income (loss)	(43,262)	19,046	14,579	48,015
Net (income) loss attributable to noncontrolling interests	339	(170)	(167)	(384)
Net income (loss) attributable to Brandywine Realty Trust	(42,923)	18,876	14,412	47,631
Distribution to preferred shareholders	0	0	0	(2,032)
Preferred share redemption charge	0	0	0	(3,181)
Nonforfeitable dividends allocated to unvested restricted shareholders	(80)	(73)	(280)	(245)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ (43,003)	$ 18,803	$ 14,132	$ 42,173
Basic income (loss) per Common Share	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Diluted income (loss) per Common Share	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Basic weighted average shares outstanding	178,602,622	175,433,657	178,515,993	175,315,581
Diluted weighted average shares outstanding	178,602,622	176,835,022	179,752,544	176,599,332
Distributions declared per Common Share	$ 0.18	$ 0.16	$ 0.54	$ 0.48
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Total revenue	$ 134,998	$ 128,438	$ 405,142	$ 387,149
Operating expenses
Property operating expenses	37,833	36,847	115,052	110,947
Real estate taxes	12,433	11,235	37,272	34,062
Third party management expenses	2,612	2,619	9,605	7,391
Depreciation and amortization	43,900	42,429	130,908	132,584
General and administrative expenses	5,963	5,813	22,209	21,797
Provision for impairment	56,865	0	56,865	3,057
Total operating expenses	159,606	98,943	371,911	309,838
Operating income (loss)	(24,608)	29,495	33,231	77,311
Other income (expense):
Interest income	1,220	79	2,564	635
Interest expense	(19,257)	(19,732)	(58,091)	(61,473)
Interest expense - amortization of deferred financing costs	(618)	(577)	(1,872)	(1,807)
Equity in income (loss) of Real Estate Ventures	1	(5,723)	(1,182)	(5,387)
Net gain (loss) on disposition of real estate	0	0	(35)	8,411
Net gain on sale of undepreciated real estate	0	953	2,859	953
Net gain on Real Estate Venture transactions	0	13,758	37,263	28,340
Net income (loss) before income taxes	(43,262)	18,253	14,737	46,983
Income tax (provision) benefit	0	793	(158)	1,032
Net income (loss)	(43,262)	19,046	14,579	48,015
Net income attributable to non-controlling interests - consolidated real estate ventures	(20)	(12)	(46)	(25)
Net income (loss) attributable to Brandywine Realty Trust	(43,282)	19,034	14,533	47,990
Distribution to preferred shareholders	0	0	0	(2,032)
Preferred share redemption charge	0	0	0	(3,181)
Nonforfeitable dividends allocated to unvested restricted shareholders	(80)	(73)	(280)	(245)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ (43,362)	$ 18,961	$ 14,253	$ 42,532
Basic income (loss) per Common Share	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Diluted income (loss) per Common Share	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Basic weighted average shares outstanding	180,082,421	176,913,456	179,995,792	176,795,380
Diluted weighted average shares outstanding	180,082,421	178,314,821	181,232,343	178,079,131
Distributions declared per Common Share	$ 0.18	$ 0.16	$ 0.54	$ 0.48
Rents [Member]
Revenue
Lease revenue	$ 107,580	$ 102,557	$ 321,597	$ 307,446
Rents [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Lease revenue	107,580	102,557	321,597	307,446
Tenant Reimbursements [Member]
Revenue
Service and other revenue	20,557	17,239	59,094	53,812
Tenant Reimbursements [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Service and other revenue	20,557	17,239	59,094	53,812
Termination Fees [Member]
Revenue
Lease revenue	498	200	1,630	2,013
Termination Fees [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Lease revenue	498	200	1,630	2,013
Third Party Management Fees, Labor Reimbursement and Leasing [Member]
Revenue
Service and other revenue	4,944	6,918	17,531	20,483
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Service and other revenue	4,944	6,918	17,531	20,483
Other [Member]
Revenue
Service and other revenue	1,419	1,524	5,290	3,395
Other [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Service and other revenue	$ 1,419	$ 1,524	$ 5,290	$ 3,395

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net income (loss)		$ (43,262)	$ 19,046	$ 14,579	$ 48,015
Comprehensive income:
Unrealized gain (loss) on derivative financial instruments		734	312	7,008	(59)
Amortization of interest rate contracts	[1]	293	314	898	905
Total comprehensive income		1,027	626	7,906	846
Comprehensive income (loss)		(42,235)	19,672	22,485	48,861
Comprehensive (income) loss attributable to noncontrolling interest		330	(174)	(233)	(391)
Comprehensive income (loss) attributable to reporting entity		(41,905)	19,498	22,252	48,470
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Net income (loss)		(43,262)	19,046	14,579	48,015
Comprehensive income:
Unrealized gain (loss) on derivative financial instruments		734	312	7,008	(59)
Amortization of interest rate contracts	[1]	293	314	898	905
Total comprehensive income		1,027	626	7,906	846
Comprehensive income (loss)		(42,235)	19,672	22,485	48,861
Comprehensive (income) loss attributable to noncontrolling interest		(20)	(12)	(46)	(25)
Comprehensive income (loss) attributable to reporting entity		$ (42,255)	$ 19,660	$ 22,439	$ 48,836
[1]	Amounts reclassified from comprehensive income to interest expense within the Consolidated Statements of Operations.

Consolidated Statements of Bene

Consolidated Statements of Beneficiaries' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Deferred Compensation, Share-based Payments [Member]	Additional Paid-in Capital [Member]	Common Stock In Grantor Trust [Member]	Cumulative Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Cumulative Distributions [Member]	Noncontrolling Interest [Member]
Beginning Balance at Dec. 31, 2016	$ 1,883,437	$ 40	$ 1,752	$ 13,684	$ 3,258,870	$ (13,684)	$ 539,319	$ (1,745)	$ (1,931,892)	$ 17,093
Beginning Balance, Shares at Dec. 31, 2016		4,000,000	175,140,760	899,457
Net income	48,015						47,631			384
Other comprehensive income	846							839		7
Redemption of Preferred Shares	(96,850)	$ (40)			(96,810)
Redemption of Preferred Shares, Shares		(4,000,000)
Issuance of partnership interest in consolidated real estate ventures	85									85
Distributions from consolidated real estate ventures	(46)									(46)
Equity issuance costs	(499)				(499)
Bonus share issuance	110				110
Bonus share issuance, Shares			6,752
Share-based compensation activity	5,907		$ 3		5,900		4
Share-based compensation activity, Shares			333,127	39,870
Share Issuance from/(to) Deferred Compensation Plan	(48)			$ 406	(48)	(406)
Share Issuance from/(to) Deferred Compensation Plan, Shares			(1,718)	61,639
Share Choice Plan Issuance, Shares			(1,423)
Reallocation of Noncontrolling interest					(42)					42
Preferred Share distributions	(2,032)								(2,032)
Preferred Share redemption charges	(3,181)								(3,181)
Distributions declared	(85,174)								(84,463)	(711)
Ending Balance at Sep. 30, 2017	1,750,570		$ 1,755	$ 14,090	3,167,481	(14,090)	586,954	(906)	(2,021,568)	16,854
Ending Balance, Shares at Sep. 30, 2017			175,477,498	1,000,966
Beginning Balance at Dec. 31, 2017	1,846,600		$ 1,784	$ 12,445	3,218,564	(12,445)	660,174	2,399	(2,053,741)	17,420
Beginning Balance, Shares at Dec. 31, 2017			178,285,236	894,736
Net income	14,579						14,412			167
Other comprehensive income	7,906							7,840		66
Issuance of Common Shares of Beneficial Interest	416				416
Issuance of Common Shares of Beneficial Interest, Shares			23,311
Issuance of partnership interest in consolidated real estate ventures	16									16
Distributions from consolidated real estate ventures	(54)									(54)
Share-based compensation activity	4,972		$ 2		4,957		13
Share-based compensation activity, Shares			196,151
Share Issuance from/(to) Deferred Compensation Plan	(111)		$ 1	$ 1,576	(112)	(1,576)
Share Issuance from/(to) Deferred Compensation Plan, Shares			99,189	82,384
Share Choice Plan Issuance, Shares			(1,285)
Reallocation of Noncontrolling interest					(8)					8
Preferred Share distributions	0
Distributions declared	(97,521)								(96,722)	(799)
Ending Balance at Sep. 30, 2018	$ 1,776,803		$ 1,787	$ 14,021	$ 3,223,817	$ (14,021)	$ 674,599	$ 10,239	$ (2,150,463)	$ 16,824
Ending Balance, Shares at Sep. 30, 2018			178,602,602	977,120

Consolidated Statements of Be_2

Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Distributions declared per Common Share	$ 0.54	$ 0.48
Cumulative Distributions [Member]
Distributions declared per Common Share	0.54	0.48
Noncontrolling Interest [Member]
Distributions declared per Common Share	$ 0.54	$ 0.48

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income	$ 14,579	$ 48,015
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	130,908	132,584
Amortization of deferred financing costs	1,872	1,807
Amortization of debt discount/(premium), net	527	1,069
Amortization of stock compensation costs	5,143	4,321
Straight-line rent income	(10,102)	(21,002)
Amortization of acquired above (below) market leases, net	(2,313)	(2,280)
Straight-line ground rent expense	231	66
Provision for doubtful accounts	1,238	1,622
Net gain on real estate venture transactions	(37,263)	(28,340)
Net gain on sale of interests in real estate	(2,824)	(9,364)
Provision for impairment	56,865	3,057
Other than temporary impairment	0	4,844
Income from Real Estate Ventures, net of distributions	2,811	199
Income tax provision (benefit)	158	(1,133)
Changes in assets and liabilities:
Accounts receivable	4,165	(4,445)
Other assets	(9,831)	(8,361)
Accounts payable and accrued expenses	1,544	6,743
Deferred income, gains and rent	(3,461)	(3,160)
Other liabilities	290	2,107
Net cash provided by operating activities	154,537	128,349
Cash flows from investing activities:
Acquisition of properties	(40,240)	(34,748)
Proceeds from the sale of properties	16,771	114,821
Proceeds from real estate venture sales	42,953	59,022
Issuance of mortgage note receivable	(44,430)	0
Proceeds from repayment of mortgage notes receivable	141	0
Capital expenditures for tenant improvements	(43,142)	(44,902)
Capital expenditures for redevelopments	(31,312)	(21,951)
Capital expenditures for developments	(70,297)	(53,560)
Advances for the purchase of tenant assets, net of repayments	739	1,148
Investment in unconsolidated Real Estate Ventures	(646)	(5,243)
Deposits for real estate	(5,550)	605
Capital distributions from Real Estate Ventures	5,101	14,906
Leasing costs paid	(10,664)	(12,553)
Net cash (used in) provided by investing activities	(180,576)	17,545
Cash flows from financing activities:
Repayments of mortgage notes payable	(4,972)	(3,681)
Proceeds from credit facility borrowings	0	264,000
Repayments of credit facility borrowings	0	(86,000)
Repayments of unsecured notes	0	(300,000)
Debt financing costs paid	(2,704)	0
Redemption of preferred shares	0	(100,000)
Proceeds from the exercise of stock options	0	1,229
Proceeds from the issuance of common shares	416	0
Shares used for employee taxes upon vesting of share awards	(1,494)	(674)
Partner contributions to consolidated real estate venture	15	85
Partner distributions from consolidated real estate venture	(54)	(46)
Distributions paid to shareholders	(96,626)	(88,162)
Distributions to noncontrolling interest	(799)	(711)
Net cash used in financing activities	(106,218)	(313,960)
Decrease in cash and cash equivalents and restricted cash	(132,257)	(168,066)
Cash and cash equivalents and restricted cash at beginning of year	203,442	194,618
Cash and cash equivalents and restricted cash at end of period	71,185	26,552
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the nine months ended September 30, 2018 and 2017 of $2,578 and $2,975, respectively	52,888	58,252
Cash paid for income taxes	405	225
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	32,492	28,391
Change in construction-in-progress related to non-cash disposition of land	22,625	0
Change in deferred income, gains and rent to the non-cash disposition of land	(25,462)	0
Change in investment in real estate ventures as a result of dispositions	(17,313)	(30,584)
Change in real estate ventures as a result of other than temporary impairment	0	(4,844)
Change in operating real estate related to a non-cash acquisition of an operating property	(20,653)	0
Change in intangible assets, net related to non-cash acquisition of an operating property	(3,144)	0
Change in acquired lease intangibles, net related to non-cash acquisition of an operating property	182	0
Change in investments in joint venture related to non-cash acquisition of property	(2,042)	0
Change in mortgage notes payable related to acquisition of an operating property	9,940	0
Change in capital expenditures financed through accounts payable at period end	992	(1,455)
Change in capital expenditures financed through retention payable at period end	2,352	83
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income	14,579	48,015
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	130,908	132,584
Amortization of deferred financing costs	1,872	1,807
Amortization of debt discount/(premium), net	527	1,069
Amortization of stock compensation costs	5,143	4,321
Straight-line rent income	(10,102)	(21,002)
Amortization of acquired above (below) market leases, net	(2,313)	(2,280)
Straight-line ground rent expense	231	66
Provision for doubtful accounts	1,238	1,622
Net gain on real estate venture transactions	(37,263)	(28,340)
Net gain on sale of interests in real estate	(2,824)	(9,364)
Provision for impairment	56,865	3,057
Other than temporary impairment	0	4,844
Income from Real Estate Ventures, net of distributions	2,811	199
Income tax provision (benefit)	158	(1,133)
Changes in assets and liabilities:
Accounts receivable	4,165	(4,445)
Other assets	(9,831)	(8,361)
Accounts payable and accrued expenses	1,544	6,743
Deferred income, gains and rent	(3,461)	(3,160)
Other liabilities	290	2,107
Net cash provided by operating activities	154,537	128,349
Cash flows from investing activities:
Acquisition of properties	(40,240)	(34,748)
Proceeds from the sale of properties	16,771	114,821
Proceeds from real estate venture sales	42,953	59,022
Issuance of mortgage note receivable	(44,430)	0
Proceeds from repayment of mortgage notes receivable	141	0
Capital expenditures for tenant improvements	(43,142)	(44,902)
Capital expenditures for redevelopments	(31,312)	(21,951)
Capital expenditures for developments	(70,297)	(53,560)
Advances for the purchase of tenant assets, net of repayments	739	1,148
Investment in unconsolidated Real Estate Ventures	(646)	(5,243)
Deposits for real estate	(5,550)	605
Capital distributions from Real Estate Ventures	5,101	14,906
Leasing costs paid	(10,664)	(12,553)
Net cash (used in) provided by investing activities	(180,576)	17,545
Escrowed cash	0	0
Cash flows from financing activities:
Repayments of mortgage notes payable	(4,972)	(3,681)
Proceeds from credit facility borrowings	0	264,000
Repayments of credit facility borrowings	0	(86,000)
Repayments of unsecured notes	0	(300,000)
Debt financing costs paid	(2,704)
Redemption of preferred shares	0	(100,000)
Proceeds from the exercise of stock options	0	1,229
Proceeds from the issuance of common shares	416	0
Shares used for employee taxes upon vesting of share awards	(1,494)	(674)
Partner contributions to consolidated real estate venture	15	85
Partner distributions from consolidated real estate venture	(54)	(46)
Distributions paid to shareholders	(97,425)	(88,873)
Net cash used in financing activities	(106,218)	(313,960)
Decrease in cash and cash equivalents and restricted cash	(132,257)	(168,066)
Cash and cash equivalents and restricted cash at beginning of year	203,442	194,618
Cash and cash equivalents and restricted cash at end of period	71,185	26,552
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the nine months ended September 30, 2018 and 2017 of $2,578 and $2,975, respectively	52,888	58,252
Cash paid for income taxes	405	225
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	32,492	28,391
Change in construction-in-progress related to non-cash disposition of land	22,625	0
Change in deferred income, gains and rent to the non-cash disposition of land	(25,462)	0
Change in investment in real estate ventures as a result of dispositions	(17,313)	(30,584)
Change in real estate ventures as a result of other than temporary impairment	0	(4,844)
Change in operating real estate related to a non-cash acquisition of an operating property	(20,653)	0
Change in intangible assets, net related to non-cash acquisition of an operating property	(3,144)	0
Change in acquired lease intangibles, net related to non-cash acquisition of an operating property	182	0
Change in investments in joint venture related to non-cash acquisition of property	(2,042)	0
Change in mortgage notes payable related to acquisition of an operating property	9,940	0
Change in capital expenditures financed through accounts payable at period end	992	(1,455)
Change in capital expenditures financed through retention payable at period end	$ 2,352	$ 83

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Capitalized interest	$ 2,578	$ 2,975
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Capitalized interest	$ 2,578	$ 2,975

Consolidated Statements of Part

Consolidated Statements of Partners' Equity - USD ($) $ in Thousands	Total	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interest [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P.	BRANDYWINE OPERATING PARTNERSHIP, L.P.General Partner Capital [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P.Accumulated Other Comprehensive Income (Loss) [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P.Noncontrolling Interest [Member]	BRANDYWINE OPERATING PARTNERSHIP, L.P.Series E-linked Preferred Stock [Member]
Beginning Balance at Dec. 31, 2016				$ 1,859,642	$ 1,762,764	$ (2,122)	$ 2,150	$ 96,850
Beginning Balance, Shares at Dec. 31, 2016					175,140,760			4,000,000
Net income	$ 48,015		$ 384	48,015	$ 47,990		25
Other comprehensive income	846	$ 839	7	846		846
Redemption of Preferred Mirror Units				(96,850)				$ (96,850)
Redemption of Preferred Mirror Units, Shares								(4,000,000)
Share Issuance from/(to) Deferred Compensation Plan	(48)			(48)	$ (48)
Share Issuance from/(to) Deferred Compensation Plan, Shares					1,718
Issuance of LP Units				(499)	$ (499)
Issuance of partnership interest in consolidated real estate ventures	85		85	86			86
Distributions from consolidated real estate ventures	(46)		(46)	(46)			(46)
Share Choice Plan Issuance, Shares					(1,423)
Bonus share issuance	110			110	$ 110
Bonus share issuance, Shares					6,752
Share-based compensation activity	5,907			5,907	$ 5,907
Share-based compensation activity, Shares					333,127
Adjustment of redeemable partnership units to liquidation value at period end				(2,781)	$ (2,781)
Preferred Share distributions	(2,032)			(2,032)	(2,032)
Preferred share redemption charge	(3,181)			(3,181)	(3,181)
Distributions declared to general partnership unitholders				(84,463)	(84,463)
Ending Balance at Sep. 30, 2017				1,724,706	$ 1,723,767	(1,276)	2,215
Ending Balance, Shares at Sep. 30, 2017					175,477,498
Beginning Balance at Dec. 31, 2017				1,819,682	$ 1,815,411	2,056	2,215
Beginning Balance, Shares at Dec. 31, 2017					178,285,236
Net income	14,579		167	14,579	$ 14,533		46
Other comprehensive income	7,906	$ 7,840	66	7,906		7,906
Share Issuance from/(to) Deferred Compensation Plan	(111)			(111)	$ (111)
Share Issuance from/(to) Deferred Compensation Plan, Shares					(99,189)
Issuance of LP Units				416	$ 416
Issuance of LP Units, Shares					23,311
Issuance of partnership interest in consolidated real estate ventures	16		16	16			16
Distributions from consolidated real estate ventures	(54)		$ (54)	(54)			(54)
Share Choice Plan Issuance, Shares					(1,285)
Share-based compensation activity	4,972			4,972	$ 4,972
Share-based compensation activity, Shares					196,151
Adjustment of redeemable partnership units to liquidation value at period end				2,880	$ 2,880
Preferred Share distributions	0			0
Preferred share redemption charge	$ 0			0
Distributions declared to general partnership unitholders				(96,722)	(96,722)
Ending Balance at Sep. 30, 2018				$ 1,753,564	$ 1,741,379	$ 9,962	$ 2,223
Ending Balance, Shares at Sep. 30, 2018					178,602,602

Consolidated Statements of Pa_2

Consolidated Statements of Partners' Equity (Parenthetical) - BRANDYWINE OPERATING PARTNERSHIP, L.P. - $ / shares	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Distributions to general partnership unitholders (USD per share)	$ 0.54	$ 0.48
General Partner Capital [Member]
Distributions to general partnership unitholders (USD per share)	$ 0.54	$ 0.48

Organization of the Parent Comp

Organization of the Parent Company and The Operating Partnership	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP	1. ORGANIZATION OF THE PARENT COMPANY AND THE OPERATING PARTNERSHIP The Parent Company is a self-administered and self-managed real estate investment trust (“REIT”) that provides leasing, property management, development, redevelopment, acquisition and other tenant-related services for a portfolio of office, retail and mixed-use properties. The Parent Company owns its assets and conducts its operations through the Operating Partnership and subsidiaries of the Operating Partnership. The Parent Company is the sole general partner of the Operating Partnership and, as of September 30, 2018, owned a 99.2% interest in the Operating Partnership. The Parent Company’s common shares of beneficial interest are publicly traded on the New York Stock Exchange under the ticker symbol “BDN”. As of September 30, 2018, the Company owned 93 properties that contain an aggregate of approximately 16.5 million net rentable square feet (collectively, the “Properties”). The Company’s core portfolio of operating properties, as of September 30, 2018, excludes two development properties and five redevelopment properties under construction or committed for construction (collectively, the “Core Properties”). The Properties were comprised of the following as of September 30, 2018: Number of Properties Rentable Square Feet Office properties 73 13,673,405 Mixed-use properties 4 646,741 Retail properties 1 17,884 Core Properties 78 14,338,030 Development properties 2 247,818 Redevelopment properties 5 583,719 Held for sale properties (a) 8 1,293,197 The Properties 93 16,462,764 (a) As of September 30, 2018, eight office properties were classified as held for sale in the Company’s Metropolitan Washington, D.C. segment. See Note 3, “ Real Estate Investments In addition to the Properties, as of September 30, 2018, the Company owned land held for development, comprised of 234 acres of undeveloped land, of which 37.9 acres were held for sale, 1.8 acres related to leasehold interests in two land parcels, each acquired through prepaid 99-year “Investment in Unconsolidated Real Estate Ventures,” The Company conducts its third-party real estate management services business primarily through wholly-owned management company subsidiaries. As of September 30, 2018, the management company subsidiaries were managing properties containing an aggregate of approximately 25.3 million net rentable square feet, of which approximately 16.5 million net rentable square feet related to Properties owned by the Company and approximately 8.8 million net rentable square feet related to properties owned by third parties and Real Estate Ventures. Unless otherwise indicated, all references in this Form 10-Q to square feet represent net rentable area.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
BASIS OF PRESENTATION	2. BASIS OF PRESENTATION Basis of Presentation The consolidated financial statements have been prepared by the Company pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments consist solely of normal recurring matters, and result in a fair statement of the financial position of the Company as of September 30, 2018, the results of its operations for the three- and nine-month periods ended September 30, 2018 and 2017 and its cash flows for the nine-month periods ended September 30, 2018 and 2017 have been included. The results of operations for such interim periods are not necessarily indicative of the results for a full year. These consolidated financial statements should be read in conjunction with the Parent Company’s and the Operating Partnership’s consolidated financial statements and footnotes included in their combined 2017 Annual Report on Form 10-K filed with the SEC on February 23, 2018. The Company's Annual Report on Form 10-K for the year ended December 31, 2017 contains a discussion of our significant accounting policies under Note 2, "Summary of Significant Accounting Policies". Out of Period Adjustment The Company recorded $1.2 million of impairment charges during the quarter ended December 31, 2016, which should have been recorded in the consolidated financial statements for the nine-month period ended September 30, 2017 and the year ended December 31, 2017. Management concluded that these misstatements were not material to any prior period, nor were they material to the consolidated financial statements as of and for the twelve-month periods ended December 31, 2017 and 2016. Reclassifications and Adoption of New Accounting Guidance Through the three- and nine-month periods ended September 30, 2017, the Company included $0.8 million and $1.0 million of income tax benefit in general and administrative expenses, respectively. During the fourth quarter of 2017, the Company began disaggregating our income tax provision/benefit in the consolidated statements of operations. As a result, in the statements of operations for the three- and nine-month periods ended September 30, 2017, included herein, the Company reclassified $0.8 million and $1.0 million of net income tax benefit out of general and administrative expenses into the “Income tax (provision) benefit” caption in the consolidated statements of operations to provide comparative presentation. During the first quarter of 2018, the Company adopted Financial Accounting Standards Board (the “FASB”) ASU No. 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts described as restricted cash or cash equivalents. Beginning-of-period and end-of-period total amounts shown on the statement of cash flows should include restricted cash, cash equivalents and amounts described as restricted cash or cash equivalents. The guidance does not define restricted cash or restricted cash equivalents. As of September 30, 2018 and September 30, 2017, the Company had $0.8 million and $1.3 million of restricted cash, respectively, on its consolidated balance sheets within the caption ‘Other assets.’ As a result of the adoption of this ASU, restricted cash balances are included with cash and cash equivalents balances as of the beginning and end of each period presented in the consolidated statements of cash flows. Separate line items reconciling changes in restricted cash balances to the changes in cash and cash equivalents will no longer be presented within the operating and investing sections of the consolidated statements of cash flows. As a result of the adoption of ASU 2016-18, for the nine-months ended September 30, 2017 operating cash flows increased by $0.6 million, which is reflected within the change in other assets caption . In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Under Topic 606, revenue is recognized when a customer obtains control of promised goods or services and is recognized at an amount that reflects the consideration expected to be received in exchange for such goods or services. In addition, Topic 606 requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The Company adopted Topic 606 in the first quarter of 2018 using the modified retrospective method. This adoption, which required us to evaluate incomplete contracts as of January 1, 2018, related to the Company’s point of sale revenue, management, leasing and development fee arrangements and other sundry income. The Company’s analysis of incomplete contracts resulted in no restatement of the consolidated balance sheets and statements of operations presented in its consolidated financial statements. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606. The new guidance provides a unified model to determine how revenue is recognized. To determine the proper amount of revenue to be recognized, the Company performs the following steps: (i) identify the contract with the customer, (ii) identify the performance obligations within the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations and (v) recognize revenue when (or as) a performance obligation is satisfied. The following is a summary of revenue earned by the Company’s reportable segments (see Note 12, “Segment Information,” Three-month period ended September 30, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate (a) Total Base rent $ 42,289 $ 29,116 $ 20,635 $ 5,008 $ 2,035 $ (492 ) $ 98,591 Straight-line rent 1,912 1,202 (492 ) (43 ) 65 (110 ) 2,534 Point of sale 5,905 73 287 134 56 - 6,455 Total rents 50,106 30,391 20,430 5,099 2,156 (602 ) 107,580 Tenant reimbursements 13,087 3,704 902 2,286 698 (120 ) 20,557 Termination fees 37 461 - - - - 498 Third party management fees, labor reimbursement and leasing 203 6 1,279 1,223 846 1,387 4,944 Other income 919 183 143 33 7 134 1,419 Total revenue $ 64,352 $ 34,745 $ 22,754 $ 8,641 $ 3,707 $ 799 $ 134,998 Nine-month period ended September 30, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate (a) Total Base rent $ 121,940 $ 88,929 $ 61,575 $ 14,442 $ 6,340 $ (1,464 ) $ 291,762 Straight-line rent 9,194 2,208 (645 ) 164 189 (345 ) 10,765 Point of sale 17,526 201 783 385 175 - 19,070 Total rents 148,660 91,338 61,713 14,991 6,704 (1,809 ) 321,597 Tenant reimbursements 37,585 10,795 2,687 6,258 2,124 (355 ) 59,094 Termination fees 192 1,300 138 - - - 1,630 Third party management fees, labor reimbursement and leasing 632 18 4,130 4,155 4,345 4,251 17,531 Other income 3,409 509 344 70 14 944 5,290 Total revenue $ 190,478 $ 103,960 $ 69,012 $ 25,474 $ 13,187 $ 3,031 $ 405,142 (a) Corporate includes intercompany eliminations necessary to reconcile to consolidated Company totals. Rental Revenue The Company owns, operates and manages commercial real estate. Rental revenue is earned by leasing commercial space to the Company’s tenants. Rental revenue is recognized on a straight-line basis over the term of the leases. The Company’s primary source of revenue is leases which fall under the scope of Leases (Topic 840). Point of Sale Revenue Point of sale revenue consists of parking and flexible stay revenue from the Company’s hotel operations. Point of sale service obligations are performed daily, and the customer obtains control of those services simultaneously as they are performed. Accordingly, revenue is recorded on an accrual basis as it is earned, coinciding with the services that are provided to the Company’s customers. Due to the nature of the services provided to the Company’s customers, there is a nominal amount of unearned revenue recorded as deposits on the Company’s balance sheet related to its parking and flexible stay operations. Tenant Reimbursements The Company contracts with third-party vendors and suppliers for goods and services to fulfill certain of the Company’s obligations to tenants. The Company is reimbursed by tenants for these goods and services in the period that the expenses are incurred based on the terms of the lease agreements with each tenant. Third party management fees, labor reimbursement and leasing The Company performs property management services for third-party property owners of real estate that consist of: (i) providing leasing services, (ii) property inspections, (iii) repairs and maintenance monitoring, and (iv) financial and accounting oversight. For these services, the Company earns management fees monthly, which are based on a fixed percentage of each managed property’s financial results, and is reimbursed for the labor costs incurred by its property management employees as services are rendered to the property owners. The Company determined that control over the services is passed to its customers simultaneously as performance occurs. Accordingly, management fee revenue is earned as the services are provided to the Company’s customers. Lease commissions are earned when the Company, as a broker for the third party property owner, executes a lease agreement with a tenant. Based on the terms of the Company’s lease commission contracts, it determined that control is transferred to the customer upon execution of each lease agreement. The Company’s lease commissions are earned based on a fixed percentage of rental income generated for each executed lease agreement and there is no variable income component. Development fee revenue is earned through two different sources: (i) the Company performs development services for third parties as agent and earns fixed development fees based on a percentage of construction costs incurred over the construction period, and (ii) the Company acts as a general contractor on behalf of one of its managed real estate ventures. The Company acts as the principal construction company for the real estate venture and records gross revenue as it provides construction services based on the quantifiable construction outputs. In applying the cost based output method of revenue recognition, the Company uses the actual costs incurred relative to the total estimated costs to determine its progress towards contract completion and to calculate the corresponding gross revenue and gross profit to recognize. For any costs that do not contribute to satisfying the Company’s performance obligations, it excludes such costs from its output methods of revenue recognition as the amounts are not reflective of transferring control of the outputs to the customer. The use of estimates in this calculation involves significant judgment. Other Income Other income primarily consists of sundry revenue earned for services provided to tenants. Sundry revenues are recognized simultaneously with the services provided to the Company’s tenants. Contract assets and contract liabilities As of September 30, 2018, the Company has no outstanding assets or liabilities associated with the Company’s third party management contracts. Nonfinancial Assets In February 2017, the FASB issued ASU No. 2017-05, Gains and losses from the derecognition of nonfinancial assets (ASC 610-20), to provide guidance for recognizing gains and losses from the transfer of nonfinancial assets and in-substance nonfinancial assets in contracts with non-customers, unless other specific guidance applies. The standard requires a company to derecognize nonfinancial assets once it transfers control of a distinct nonfinancial asset or distinct in-substance nonfinancial asset. Additionally, when a company transfers its controlling interest in a nonfinancial asset but retains a noncontrolling ownership interest, a company is required to measure any noncontrolling interest it receives or retains at fair value. The guidance requires companies to recognize a full gain or loss on the transaction. As a result of the new guidance, the previous guidance specific to real estate sales within ASC 360-20 will be eliminated. The Company adopted ASU 2017-05 in the first quarter of 2018 using the modified retrospective method. This adoption requires the Company to analyze incomplete contracts related to property dispositions previously accounted for under ASC 360-20 and to determine whether such arrangements had any forms of continuing involvement that may have affected the revenue or profit recognition of the transactions, including arrangements with prohibited forms of continuing involvement. The Company evaluated the following incomplete contracts to determine if the revenue recognition pattern was affected by ASU 2017-05: Garza Land Sales On July 1, 2016, the Company closed on the acquisition of 34.6 acres of land located in Austin, Texas known as the Garza Ranch, for a purchase price of $20.6 million. As of September 30, 2018, the These improvement costs were included in the sale price of each land parcel. he Company did not transfer control to the buyers of the land parcels and The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three-month period ended June 30, 2018, the infrastructure improvements were substantially completed. As a result, the Company transferred control of the land parcels to the buyers and recognized the land sales. Accordingly, during the three-month period ended June 30, 2018, the Company applied the cash proceeds received from the settlements of each parcel and recognized an aggregate $2.8 million deferred gain. There was no activity or gain recognized during the three-month period ended September 30, 2018. The following table details the gain on sale for each land parcel, as of September 30, 2018 (dollars, in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale March 16, 2018 Garza Ranch - Office Austin, TX 1 6.6 $ 14,571 $ 14,509 $ 1,424 April 28, 2017 Garza Ranch - Multifamily Austin, TX 1 8.4 11,800 11,560 1,233 January 30, 2017 Garza Ranch - Hotel Austin, TX 1 1.7 3,500 3,277 180 Total Dispositions 3 16.7 $ 29,871 $ 29,346 $ 2,837 Based on the facts and circumstances, revenue recognition under ASU 2017-05 coincides with the Company’s conclusion under ASC 360-20, and no restatement of the consolidated financial statements is necessary as a result of implementing the guidance for the sale of nonfinancial assets. Marine Piers Sublease Interest Sale On March 15, 2017, the Company sold its sublease interest in the Piers at Penn’s Landing (the “Marine Piers”), which includes leasehold improvements containing 181,900 net rentable square feet, and a marina, located in Philadelphia, Pennsylvania, for an aggregate sales price of $21.4 million. On the closing date, the buyer paid $12.0 million in cash and the Company received cash proceeds of $11.2 million, after closing costs and prorations. The $9.4 million balance of the purchase is due on (a) January 31, 2020, in the event that the tenant at the Marine Piers does not exercise an option it holds to extend the term of the sublease or (b) January 15, 2024, in the event that the tenant does exercise the option to extend the term of the sublease. In accordance with ASU 2017-05, the Company determined that it is appropriate to recognize the sale of the sublease interest in the Marine Piers and to defer the amount of the pending payment due from the buyer because the Company cannot determine the collectability of the remaining $9.4 million balance due under the purchase and sale agreement. The net book value of the Marine Piers was $4.7 million, resulting in a gain on sale of $6.5 million. The remaining gain on sale of $9.4 million arising from the pending payment will be recognized at the earlier of: (i) the time that the Company determines collection of the deferred payment is probable or (ii) on the second purchase price installment date. Based on the facts and circumstances, revenue recognition under ASU 2017-05 coincides with the Company’s previous conclusion under ASC 360-20, and therefore no restatement of the consolidated financial statements is necessary as a result of implementing the guidance for the sale of nonfinancial assets. Subaru National Training Center On December 3, 2015, the Company entered into an agreement to construct an 83,000 square foot build-to-suit service center (the “Subaru NSTC Development”) on land parcels owned by the Company for Subaru as the single tenant. Concurrently, Subaru entered into an 18-year lease for the service center. The lease is classified as a direct finance lease within the “Other assets” caption on the consolidated balance sheets. The lease contained a purchase option, which allowed Subaru to purchase the property at the commencement of the lease, or five years subsequent to inception, at depreciated cost. During the third quarter of 2018, the lease commenced and Subaru exercised its purchase option for the Subaru NSTC Development. Accordingly, the Company recognized $0.4 million in interest income during the three months ended September 30, 2018, in accordance with accounting guidance for sales-type leases. Recent Accounting Pronouncements In June 2018, the FASB issued ASU No. 2018-07 that aligns the accounting for share-based payment awards issued to employees and nonemployees. Under previously issued GAAP guidance, the accounting for nonemployee share-based payments differed from that applied to employee awards, particularly with regard to the measurement date and the impact of performance conditions. Under the revised guidance, the existing employee guidance will apply to nonemployee share-based transactions (as long as the transaction is not effectively a form of financing), with the exception of specific guidance related to the attribution of compensation cost. The cost of nonemployee awards will continue to be recorded as if the grantor had paid cash for the goods or services. In addition, the contractual term will be able to be used in lieu of an expected term in the option-pricing model for nonemployee awards. Changes to the accounting for nonemployee awards include: • Equity-classified share-based payment awards issued to nonemployees will now be measured on the grant date, instead of the previous requirement to remeasure the awards through the performance completion date. • Compensation cost associated with the award will be recognized when achievement of the performance condition is probable, rather than upon achievement of the performance condition. • The current requirement to reassess the classification (equity or liability) for nonemployee awards upon vesting will be eliminated, except for awards in the form of convertible instruments. • The revised guidance also clarifies that any share-based payment awards issued to customers should be evaluated under ASC 606, Revenue from Contracts with Customers. The amendments in this update are effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company is in the process of evaluating the impact of this new guidance on its consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12 to simplify the application of hedge accounting guidance and improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. In addition, ASU 2017-12 requires an entity to present the earnings effect of the hedging instrument in the same income statement line item in which the earnings effect of the hedged item is reported. The transition guidance provides companies with the option of early adopting the new standard using a modified retrospective transition method in any interim period after issuance of the update or requires adoption for fiscal years beginning after December 15, 2018. This adoption method requires companies to recognize the cumulative effect of initially applying the guidance as an adjustment to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the update. The Company is in the process of evaluating the impact of this new guidance on its consolidated financial statements. Leasing Standard In February 2016, the FASB issued guidance (“ASU-2016-02”) modifying the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for in the same manner as operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The guidance supersedes previously issued guidance under ASC Topic 840 “Leases.” The lease ASU requires the use of the modified retrospective transition method and does not allow for a full retrospective approach. However, it provides two options for application of the modified retrospective transition method: • Under the first option, the ASU requires the application of the standard to all leases that exist at or commence after, January 1, 2017 (the beginning of the earliest comparative period presented in the 2019 financial statements), with a cumulative adjustment to the opening balance of retained earnings on January 1, 2017, for the effect of applying the standard at the date of initial applications, and restatement of the amounts presented prior to January 1, 2019. • Under the second option, an entity may elect a package of practical expedients, which allows for the following: o An entity need not reassess whether any expired or existing contracts are or contain leases; o An entity need not reassess the lease classification for any expired or existing leases; and o An entity need not reassess initial direct costs for any existing leases. This package of practical expedients is available as a single election that must be consistently applied to all existing leases at the date of adoption. Lessors that adopt this package are not expected to reassess expired or existing leases at the date of initial application, which is January 1, 2017, under the ASU. This option enables entities to account for their existing leases for the remainder of the respective lease terms following previous accounting guidance, which eliminates the need to calculate a cumulative adjustment to the opening balance of retained earnings. In addition, there is a practical expedient that allows the Company to use hindsight when determining the lease term and assessing the fair value of right of use assets. After considering its impact, the Company has decided not to elect the hindsight expedient as part of the application of the modified retrospective transition method. Furthermore, in July 2018, the FASB adopted an amendment to the package of practical expedients that provides an optional transition method to make January 1, 2019 the initial application date of the ASU, rather than January 1, 2017. Entities that elect both the package of practical expedients and the optional transitional method will apply the new lease ASU prospectively, to leases commencing or modified after January 1, 2019, and will not be required to apply the disclosures under the new lease ASU to comparative periods. In January 2018, the FASB issued ASU No. 2018-01 to address the accounting treatment of land easements within the context of ASU No. 2016-02, Leases (Topic 842). ASU 2018-01 provides an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under the current leases guidance in Topic 840. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. In July 2018, the FASB issued ASU No. 2018-11, an amendment to the lease ASU that will allow lessors to elect, as a practical expedient, not to allocate the total consideration to lease and nonlease components based on their relative standalone selling prices. This practical expedient will allow lessors to elect a combined single lease component presentation if: (i) the timing and pattern of the revenue recognition of the combined single lease component is the same, and (ii) the related lease component and, the combined single lease component would be classified as an operating lease. Nonlease components that do not meet the criteria of this practical expedient will be accounted for under the new revenue recognition ASU. The guidance is effective on January 1, 2019, with early adoption permitted. The ASU is expected to have the following impact on the Company’s consolidated financial statements: • Under ASC 842 as a lessor, lease components are recognized on a straight line basis, while non-lease components will be recognized in accordance with the new revenue standard. The Company is in the process of evaluating its leases to determine if the timing and pattern of recognition for its lease and nonlease components is the same. If it is determined that the pattern of revenue recognition is the same for lease and nonlease components then the Company will present them within rental revenue in its consolidated statement of operations. The Company is in the process of evaluating the impact the ASU will have on its consolidated financial statements. • ASC 842 is expected to impact the Company’s consolidated financial statements as the Company has land lease arrangements for which it is the lessee. Based on the Company’s evaluation, it expects operating expenses to increase by $0.8 million as ground rent expense for certain of its CPI indexed ground leases will be recognized on a straight-line basis under the new guidance. • The Company will expense additional costs related to leasing efforts under ASC 842 compared to the previous GAAP because certain activities performed by personnel involved in the leasing process will no longer be considered incremental costs to execute a lease agreement. Based on the Company’s analysis, leasing expenses will increase by $3.6 million for the year ended December 31, 2019, as internal costs and leasing pursuit costs will be expensed as incurred under ASC 842. • The Company’s equity-method investments may adopt the standard using the timeline otherwise afforded private companies. The Company anticipates the impact of ASC 842 will be similar to the items described above. The Company has not completed its analysis of this ASU. The Company expects tenant recoveries that qualify as nonlease components will be presented under a single lease component presentation. Tenant recoveries that qualify as lease components, which relate to the right to use the leased asset (e.g., property taxes, and insurance), will be accounted for under the new lease ASU. Tenant recoveries that qualify as nonlease components, which relate to payments for goods or services that are transferred separately from the right to use the underlying asset, including tenant recoveries pertaining to payments for maintenance activities and common area expenses, would be accounted for under the new revenue recognition ASU upon adoption of the new lease ASU. Additionally, the Company has determined that it is going to elect to apply the package of practical expedients when applying the modified retrospective approach.

Real Estate Investments

Real Estate Investments	9 Months Ended
	Sep. 30, 2018
Real Estate [Abstract]
REAL ESTATE INVESTMENTS	3. REAL ESTATE INVESTMENTS As of September 30, 2018 and December 31, 2017, the gross carrying value of the operating properties was as follows (in thousands): September 30, December 31, 2018 2017 Land $ 437,640 $ 492,197 Building and improvements 2,579,740 2,896,113 Tenant improvements 411,668 444,038 Operating properties 3,429,048 3,832,348 Assets held for sale - real estate investments 396,072 - Total $ 3,825,120 $ 3,832,348 Acquisitions On June 29, 2018, the Company acquired, through a 99-year ground lease, the leasehold interest in a one-acre land parcel, located at 3025 JFK Boulevard, in Philadelphia, Pennsylvania. The Company prepaid $15.0 million of ground lease rent and, in accordance with ASC 840, capitalized $0.3 million of costs related to entering the lease. Additionally, the ground lease required the Company to pay $5.6 million for a leasehold valuation credit, which can be applied to increase the density of the projects subject to the Schuylkill Yards Project master development agreement. Of this credit, $2.4 million will be applied to the development of 3001-3003 and 3025 JFK Boulevard if the Company constructs a minimum of 1.2 million square feet of floor area ratio (“FAR”) on these land parcels. The remaining credit of $3.2 million can be used for development in excess of 1.2 million FAR at 3001-3003 and 3025 JFK Boulevard or toward future ground lease takedowns at the Schuylkill Yards Development Site. This $3.2 million credit is reimbursed if the master development agreement is terminated by the landowner. Based on the Company’s evaluation under ASC 840, the ground lease is classified as an operating lease. The ground lease and credit are included in the “Prepaid leasehold interests in land held for development, net,” and “Other assets” captions, respectively, in the consolidated balance sheets. On March 22, 2018, the Company acquired, through a 99-year ground lease, the leasehold interest in a one-acre land parcel, located at 3001-3003 JFK Boulevard, in Philadelphia, Pennsylvania. The Company prepaid $24.6 million of ground lease rent and, in accordance with ASC 840, capitalized $0.3 million of costs related to entering the lease. Based on the Company’s evaluation under ASC 840, the ground lease is classified as an operating lease and included in the “Prepaid leasehold interests in land held for development, net,” caption in the consolidated balance sheets. On January 5, 2018, the Company acquired, from its then partner in each of the Four Tower Bridge real estate venture and the Seven Tower Bridge real estate venture, the partner’s 35% ownership interest in the Four Tower Bridge real estate venture in exchange for the Company's 20% ownership interest in the Seven Tower Bridge real estate venture. As a result of this non-monetary exchange, the Company acquired 100% of the Four Tower Bridge real estate venture, which owns an office property containing 86,021 square feet, in Conshohocken, Pennsylvania, encumbered with $9.7 million in debt. The Company previously accounted for its noncontrolling interest in Four Tower Bridge using the equity method. As a result of the exchange transaction, the Company obtained control of the Four Tower Bridge property. The Company’s acquisition of the 35% ownership interest in Four Tower Bridge from its former partner resulted in the consolidation of the property, which has been accounted for as an asset acquisition under ASU 2017-01. As such, the Company capitalized $0.1 million of acquisition-related costs and allocated the unencumbered acquisition value, consisting of the fair value of $23.6 million and the acquisition-related costs, to tangible and intangible assets and liabilities. The unencumbered acquisition value was determined under the comparative sales approach, which utilized observable transactions within the Conshohocken submarket. The Company ut ilized a number of sources in making estimates of fair value for purposes of allocating the acquisition value to tangible and intangible assets acquired. The acquisition value has been allocated as follows (in thousands): January 5, 2018 Building, land and improvements $ 20,734 Intangible assets acquired (a) 3,144 Below market lease liabilities assumed (b) (182 ) Total unencumbered acquisition value $ 23,696 Mortgage debt assumed - at fair value (c) (9,940 ) Total encumbered acquisition value $ 13,756 Total unencumbered acquisition value 23,696 Mortgage debt assumed - at fair value (c) (9,940 ) Investment in unconsolidated real estate ventures (3,502 ) Net working capital assumed 1,379 Gain on real estate venture transactions $ 11,633 (a) (b) (c) Four Tower Bridge contributed approximately $0.7 million and $2.1 million of revenue and $0.1 million of net income and $0.1 million of net loss, included in the Company’s consolidated income statements, for the three- and nine-month periods ended September 30, 2018, respectively. Dispositions The Company sold the following office property during the nine-month period ended September 30, 2018 (dollars in thousands): Disposition Date Property/Portfolio Name Location Type Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Loss on Sale June 21, 2018 20 East Clementon Road Gibbsboro, NJ Office 1 38,260 $ 2,000 $ 1,850 $ (35 ) Total Dispositions 1 38,260 $ 2,000 $ 1,850 $ (35 ) The Company sold the following land parcels during the nine-month period ended September 30, 2018 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale March 16, 2018 Garza Ranch - Office Austin, TX 1 6.6 $ 14,571 $ 14,509 $ 1,424 (a) January 10, 2018 Westpark Land Durham, NC 1 13.1 485 412 22 Total Dispositions 2 19.7 $ 15,056 $ 14,921 $ 1,446 (a) As of March 31, 2018, the Company had not transferred control to the buyer of this land parcel, or two other parcels at this site which were sold during 2017, because of a completion guarantee which required the Company, as developer, to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three months ended June 30, 2018, the infrastructure improvements were substantially completed, at which time the Company transferred control of the land parcels. As a result, the Company then recognized the sale. See Note 2, “Basis of Presentation,” for further discussion of the infrastructure improvements and related revenue recognition The sales of property and land referenced above do not represent a strategic shift that has a major effect on the Company’s operations and financial results. Accordingly, the operating results of these properties remain classified within continuing operations for all periods presented. Held for Sale The following is a summary of properties classified as held for sale but which did not meet the criteria to be classified within discontinued operations at September 30, 2018 (in thousands): Held for Sale Properties Included in Continuing Operations September 30, 2018 Metropolitan Washington, D.C. - Office (a) Pennsylvania Suburbs - Land (b) Other - Land (b) Total ASSETS HELD FOR SALE Real estate investments: Operating properties $ 396,072 $ - $ - $ 396,072 Accumulated depreciation (112,600 ) - - (112,600 ) Operating real estate investments, net 283,472 - - 283,472 Construction-in-progress 1,748 - - 1,748 Land inventory - 4,254 7,321 11,575 Total real estate investments 285,220 4,254 7,321 296,795 Other assets 399 - - 399 Total assets held for sale, net $ 285,619 $ 4,254 $ 7,321 $ 297,194 LIABILITIES HELD FOR SALE Other liabilities $ 826 $ - $ - $ 826 Total liabilities held for sale $ 826 $ - $ - $ 826 (a) As of September 30, 2018, the Company determined that the sale of eight office properties, containing 1,293,197 rentable square feet, in the Metropolitan Washington, D.C. segment, was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the $366.0 million carrying value of the properties exceeded the estimated $309.1 million fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $56.9 million during the three-month period ended September 30, 2018. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of ten years and residual capitalization rates and discount rates of 7.47% and 8.60%, respectively. The results were comparable to indicative pricing in the market. As significant inputs to the model are unobservable, the Company determined that the value determined for this property falls within Level 3 fair value reporting. (b) As of September 30, 2018, the Company determined that the sale of one land parcel in the Pennsylvania Suburbs segment and two parcels of land in the Other segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the fair value less the anticipated costs of sale of the properties exceeded the carrying values. As a result, the Company expects to record gains on sale. The fair value measurement will be based on the pricing in the purchase and sale agreements. The disposals of the properties referenced above do not represent a strategic shift that has a major effect on the operations and financial results of the Company. As a result, the operating results of the properties remain classified within continuing operations for all periods presented.

Investment in Unconsolidated Re

Investment in Unconsolidated Real Estate Ventures	9 Months Ended
	Sep. 30, 2018
Equity Method Investments And Joint Ventures [Abstract]
INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES	4. INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES As of September 30, 2018, the Company held ownership interests in 10 unconsolidated Real Estate Ventures for an aggregate investment balance of $167.8 million. The Company formed or acquired interests in these Real Estate Ventures with unaffiliated third parties to develop or manage office, residential and/or mixed-use properties or to acquire land in anticipation of possible development of office, residential and/or mixed-use properties. As of September 30, 2018, six of the real estate ventures owned properties that contain an aggregate of approximately 6.6 million net rentable square feet of office space; two real estate ventures owned 1.4 acres of land held for development; one real estate venture owned 1.3 acres of land in active development; and one real estate venture owned a residential tower that contains 321 apartment units. The Company accounts for its unconsolidated interests in the Real Estate Ventures using the equity method. The Company’s unconsolidated interests range from 25% to 70%, subject to specified priority allocations of distributable cash in certain of the Real Estate Ventures. The Company earned management fees from its Real Estate Ventures of $1.4 million and $4.0 million for the three- and nine-month periods ended September 30, 2018, respectively, and $1.7 million and $4.9 million for the three- and nine-month periods ended September 30, 2017, respectively. The Company earned leasing commission income from its Real Estate Ventures of $1.5 million and $4.4 million for the three- and nine-month periods ended September 30, 2018, respectively, and $1.9 million and $5.5 million for the three- and nine-month periods ended September 30, 2017, respectively. The Company had outstanding accounts receivable balances from its Real Estate Ventures of $1.2 million and $0.9 million as of September 30, 2018 and December 31, 2017, respectively. The amounts reflected in the following tables (except for the Company’s share of equity and income) are based on the financial information of the individual Real Estate Ventures. The Company does not record operating losses of a Real Estate Venture in excess of its investment balance unless the Company is liable for the obligations of the Real Estate Venture or is otherwise committed to provide financial support to the Real Estate Venture. The following is a summary of the financial position of the Real Estate Ventures in which the Company held interests as of September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) (a) Other Total Net property $ 258,424 $ 157,824 $ - $ 504,652 $ 920,900 Other assets 39,398 23,133 - 83,835 146,366 Other liabilities 18,705 4,347 - 68,042 91,094 Debt, net 246,158 92,642 - 321,241 660,041 Equity (b) 32,959 83,968 - 199,204 316,131 December 31, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Net property $ 263,557 $ 158,960 $ 143,990 $ 517,458 $ 1,083,965 Other assets 42,272 24,181 8,563 86,916 161,932 Other liabilities 24,131 4,493 1,648 67,435 97,707 Debt, net 248,700 92,917 110,136 314,667 766,420 Equity (b) 32,998 85,731 40,769 222,272 381,770 (a) On January 10, 2018, HSRE-BDN I, LLC (evo at Cira Centre South) sold the 345-unit student housing tower, its sole operating asset. See ‘evo at Cira Disposition’ section below. (b) This amount includes the effect of the basis difference between the Company's historical cost basis and the basis recorded at the Real Estate Venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from the impairment of investments, purchases of third party interests in existing Real Estate Ventures and upon the transfer of assets that were previously owned by the Company into a Real Estate Venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the Real Estate Venture level. The following is a summary of results of operations of the Real Estate Ventures in which the Company held interests during the three- and nine-month periods ended September 30, 2018 and 2017 (in thousands): Three-month period ended September 30, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 14,232 $ 5,962 $ - $ 21,823 $ 42,017 Operating expenses (6,428 ) (2,589 ) - (12,123 ) (21,140 ) Interest expense, net (2,549 ) (873 ) - (4,122 ) (7,544 ) Depreciation and amortization (4,896 ) (2,232 ) - (6,135 ) (13,263 ) Loss on early extinguishment of debt - - - (334 ) (334 ) Net income (loss) $ 359 $ 268 $ - $ (891 ) $ (264 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 180 $ 134 $ - $ (550 ) $ (236 ) Basis adjustments and other 243 31 - (37 ) 237 Equity in income (loss) of Real Estate Ventures $ 423 $ 165 $ - $ (587 ) $ 1 Three-month period ended September 30, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 22,493 $ 8,438 $ 3,009 $ 22,571 $ 56,511 Operating expenses (10,107 ) (4,359 ) (841 ) (12,111 ) (27,418 ) Interest expense, net (3,784 ) (1,384 ) (1,097 ) (5,406 ) (11,671 ) Depreciation and amortization (9,334 ) (3,251 ) (1,128 ) (6,970 ) (20,683 ) Net loss $ (732 ) $ (556 ) $ (57 ) $ (1,916 ) $ (3,261 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net loss $ (366 ) $ (278 ) $ (29 ) $ (1,002 ) $ (1,675 ) Other-than-temporary impairment - (4,844 ) - - $ (4,844 ) Basis adjustments and other 351 (8 ) 53 400 796 Equity in income (loss) of Real Estate Ventures $ (15 ) $ (5,130 ) $ 24 $ (602 ) $ (5,723 ) Nine-month period ended September 30, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 42,492 $ 17,768 $ 995 $ 64,684 $ 125,939 Operating expenses (18,245 ) (8,010 ) (250 ) (35,492 ) (61,997 ) Interest expense, net (7,070 ) (2,606 ) (388 ) (13,558 ) (23,622 ) Depreciation and amortization (15,622 ) (6,915 ) (376 ) (18,526 ) (41,439 ) Loss on early extinguishment of debt - - (718 ) (334 ) (1,052 ) Net income (loss) $ 1,555 $ 237 $ (737 ) $ (3,226 ) $ (2,171 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 778 $ 119 $ (369 ) $ (1,946 ) $ (1,418 ) Basis adjustments and other 378 33 11 (186 ) 236 Equity in income (loss) of Real Estate Ventures $ 1,156 $ 152 $ (358 ) $ (2,132 ) $ (1,182 ) Nine-month period ended September 30, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 70,185 $ 23,751 $ 9,264 $ 66,409 $ 169,609 Operating expenses (29,119 ) (10,547 ) (2,232 ) (35,858 ) (77,756 ) Interest expense, net (11,217 ) (3,830 ) (3,009 ) (15,716 ) (33,772 ) Depreciation and amortization (27,627 ) (9,193 ) (3,384 ) (21,612 ) (61,816 ) Net income (loss) $ 2,222 $ 181 $ 639 $ (6,777 ) $ (3,735 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 1,111 $ 91 $ 320 $ (2,909 ) $ (1,387 ) Other-than-temporary impairment - (4,844 ) - - (4,844 ) Basis adjustments and other 155 291 105 293 844 Equity in income (loss) of Real Estate Ventures $ 1,266 $ (4,462 ) $ 425 $ (2,616 ) $ (5,387 ) (a) The Company’s unconsolidated ownership interests ranged from 25% to 70% during the three- and nine-month periods ended September 30, 2018 and 20% to 70% during the three- and nine-month periods ended September 30, 2017, subject to specified priority allocations of distributable cash in certain of the Real Estate Ventures. MAP Venture On August 1, 2018, MAP Ground Lease Venture LLC (“MAP Venture”), in which the Company holds a 50% ownership interest, refinanced its $180.8 million third party debt financing, secured by the buildings of MAP Venture and maturing February 9, 2019, with $185.0 million third party debt financing, also secured by the buildings, bearing interest at LIBOR + 2.45% capped at a total maximum interest of 6.00% and maturing on August 1, 2023. The Company accounts for its investment in MAP Venture under the equity method of accounting. Based upon the reconsideration event caused by the refinancing of the MAP Venture’s third party debt financing, the Company reassessed its consolidation conclusion. The Company determined that this Real Estate Venture is no longer a VIE in accordance with the accounting standard for the consolidation of VIEs because MAP Venture, through the refinancing of the construction facility and without further support from the Company or its partner in the venture, demonstrated that it has sufficient equity at risk to finance its activities. As a result, the Company is using the voting interest model under the accounting standard for consolidation in order to determine whether to consolidate MAP Venture. Based upon each member's substantive participating rights over the activities that significantly impact the operations and revenues of MAP Venture under the operating agreement and related agreements, MAP Venture is not consolidated by the Company, and is accounted for under the equity method of accounting. As a result of this transaction, the Company did not gain a controlling financial interest over MAP Venture; therefore, it was not required to remeasure its previously held equity interest to fair value at the date that it acquired the additional equity interest. Brandywine 1919 Ventures On June 26, 2018, each of the Company and its partner, LCOR/Calstrs, provided a $44.4 million mortgage loan to Brandywine 1919 Ventures (“1919 Ventures”), an unconsolidated real estate venture in which each of the Company and LCOR/Calstrs holds a 50% consolidated balance sheets. The loans bear interest at a fixed 4.0% per annum interest rate with a scheduled maturity on June 25, 2023 . On June 26, 2018, Brandywine 1919 Ventures used the loan to repay the venture’s then outstanding $88.8 million construction loan, comprised of $88.6 million in principal and $ 0.2 million of accrued interest. On an ongoing basis, the Company will evaluate its loan for collectability. There are no collectabili ty concerns as of September 30, 2018. The Company accounts for its investment in 1919 Ventures under the equity method of accounting. Based upon the reconsideration event caused by the refinancing of 1919 Ventures’ construction facility, the Company reassessed its consolidation conclusion. The Company determined that this real estate venture is no longer a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company is using the voting interest model under the accounting standard for consolidation in order to determine whether to consolidate 1919 Ventures. The partner mortgage loans do not impact the controlling rights within the partnership agreements. Based upon each member's substantive participating rights over the activities that significantly impact the operations and revenues of 1919 Ventures under the operating agreement and related partnership agreements, 1919 Ventures is not consolidated by the Company, and is accounted for under the equity method of accounting. As a result of this transaction, the Company did not gain a controlling financial interest over 1919 Ventures; therefore, it was not required to remeasure its previously held equity interest to fair value at the date that it acquired the additional equity interest. Four Tower Bridge Acquisition On January 5, 2018, the Company acquired, from its then partner in each of the Four Tower Bridge real estate venture and the Seven Tower Bridge real estate venture, the partner’s remaining 35% ownership interest in the Four Tower Bridge real estate venture in exchange for the Company's 20% ownership interest in the Seven Tower Bridge real estate venture. The Four Tower Bridge real estate venture owned an office property containing 86,021 square feet in Conshohocken, Pennsylvania encumbered with $9.7 million in debt. The Company previously accounted for its noncontrolling interest in Four Tower Bridge using the equity method. As a result of the exchange transaction, the Company obtained control of the Four Tower Bridge property and recognized a gain of $11.6 million. For further information regarding the accounting of the transaction, see Note 3, “ Real Estate Investments. evo at Cira Disposition On January 10, 2018, evo at Cira, a real estate venture in which the Company held a 50% interest, sold its sole asset, a 345-unit student housing tower, at a gross sales value of $197.5 million. The student housing tower, located in Philadelphia, Pennsylvania, was encumbered by a secured loan with a principal balance of $110.9 million at the time of sale, which was repaid in full from the sale proceeds. The Company’s share of net cash proceeds from the sale, after debt repayment and closing costs, was $43.0 million. As the Company’s investment basis was $17.3 million, a gain of $25.7 million was recorded. Guarantees As of September 30, 2018, the Real Estate Ventures had aggregate indebtedness of $664.2 million. These loans are generally mortgage or construction loans, most of which are non-recourse to the Company, except for customary carve-outs. As of September 30, 2018, the loans for which there is recourse to the Company consist of the following: (

Intangible Assets and Liabiliti

Intangible Assets and Liabilities	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS AND LIABILITIES	5. INTANGIBLE ASSETS AND LIABILITIES As of September 30, 2018 and December 31, 2017, the Company’s intangible assets/liabilities were comprised of the following (in thousands): September 30, 2018 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 103,339 $ (51,072 ) $ 52,267 Tenant relationship value 9,597 (8,420 ) 1,177 Above market leases acquired 4,711 (3,016 ) 1,695 Total intangible assets, net $ 117,647 $ (62,508 ) $ 55,139 Acquired lease intangibles, net: Below market leases acquired $ 34,523 $ (16,843 ) $ 17,680 December 31, 2017 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 108,060 $ (47,003 ) $ 61,057 Tenant relationship value 11,201 (9,275 ) 1,926 Above market leases acquired 4,545 (2,556 ) 1,989 Total intangible assets, net $ 123,806 $ (58,834 ) $ 64,972 Acquired lease intangibles, net: Below market leases acquired $ 36,213 $ (15,939 ) $ 20,274 As of September 30, 2018, the Company’s annual amortization for its intangible assets/liabilities, assuming no prospective early lease terminations, are as follows (dollars in thousands): Assets Liabilities 2018 (three months remaining) $ 3,645 $ 844 2019 12,735 2,833 2020 10,140 2,069 2021 7,538 1,432 2022 5,355 1,264 Thereafter 15,726 9,238 Total $ 55,139 $ 17,680

Debt Obligations

Debt Obligations	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
DEBT OBLIGATIONS	6. DEBT OBLIGATIONS The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 December 31, 2017 Effective Interest Rate Maturity Date MORTGAGE DEBT: Two Logan Square $ 83,220 $ 84,440 3.98% May 2020 Four Tower Bridge 9,583 - 4.50% (a) Feb 2021 One Commerce Square 121,066 123,667 3.64% Apr 2023 Two Commerce Square 111,017 112,000 4.51% Apr 2023 Principal balance outstanding 324,886 320,107 Plus: fair market value premium (discount), net (1,853 ) (2,325 ) Less: deferred financing costs (445 ) (566 ) Mortgage indebtedness $ 322,588 $ 317,216 UNSECURED DEBT Seven-Year Term Loan - Swapped to fixed $ 250,000 $ 250,000 3.72% Oct 2022 $350.0M 3.95% Guaranteed Notes due 2023 350,000 350,000 3.87% Feb 2023 $250.0M 4.10% Guaranteed Notes due 2024 250,000 250,000 4.33% Oct 2024 $450.0M 3.95% Guaranteed Notes due 2027 450,000 450,000 4.03% Nov 2027 $250.0M 4.55% Guaranteed Notes due 2029 250,000 250,000 4.60% Oct 2029 Indenture IA (Preferred Trust I) 27,062 27,062 LIBOR + 1.25% Mar 2035 Indenture IB (Preferred Trust I) - Swapped to fixed 25,774 25,774 3.30% Apr 2035 Indenture II (Preferred Trust II) - Swapped to fixed 25,774 25,774 3.09% Jul 2035 Principal balance outstanding 1,628,610 1,628,610 Plus: original issue premium (discount), net (4,178 ) (4,423 ) Less: deferred financing costs (9,483 ) (10,575 ) Total unsecured indebtedness $ 1,614,949 $ 1,613,612 Total Debt Obligations $ 1,937,537 $ 1,930,828 (a) This loan was assumed upon acquisition of the related property on January 5, 2018. The interest rate reflects the market rate at the time of acquisition. As of September 30, 2018 and December 31, 2017, On July 17, 2018, the Company executed the Amended and Restated Revolving Credit Agreement (as amended and restated, the “2018 Credit Facility”). The amendment and restatement, among other things: (i) maintained the total commitment of the revolving line of credit of $600.0 million; (ii) extended the maturity date from May 15, 2019 to July 15, 2022, with two six-month extensions at the Company’s election subject to specified conditions and subject to payment of an extension fee; (iii) reduced the interest rate margins applicable to Eurodollar loans; (iv) provided for an additional interest rate option based on a floating LIBOR rate; and (v) removed the covenant requiring the Company to maintain a minimum net worth. In connection with the amendments, the Company capitalized $2.7 million in financing costs, which will be amortized through the July 15, 2022 maturity date. At the Company's option, loans outstanding under the 2018 Credit Facility will bear interest at a rate per annum equal to (1) LIBOR plus between 0.775% and 1.45%, based on the Company's credit rating, or (2) a base rate equal to the greatest of (a) the Administrative Agent's prime rate, (b) the Federal Funds rate plus 0.5% or (c) LIBOR for a one month period plus 1.00%, in each case, plus a margin ranging from 0.0% to 0.45% based on the Company's credit rating. The 2018 Credit Facility also contains a competitive bid option that allows banks that are part of the lender consortium to bid to make loan advances to the Company at a reduced interest rate. In addition, the Company is also obligated to pay (1) in quarterly installments a facility fee on the total commitment at a rate per annum ranging from 0.125% to 0.30% based on the Company's credit rating and (2) an annual fee on the undrawn amount of each letter or credit equal to the LIBOR Margin. Based on the Company's current credit rating, the LIBOR margin is 1.10% and the facility fee is 0.25%. The terms of the 2018 Credit Facility require that the Company maintain customary financial and other covenants, including: (i) a fixed charge coverage ratio greater than or equal to 1.5 to 1.00; (ii) a leverage ratio less than or equal to 0.60 to 1.00, subject to specified exceptions; (iii) a ratio of unsecured indebtedness to unencumbered asset value less than or equal to 0.60 to 1.00, subject to specified exceptions; (iv) a ratio of secured indebtedness to total asset value less than or equal to 0.40 to 1.00; and (v) a ratio of unencumbered cash flow to interest expense on unsecured debt greater than 1.75 to 1.00. In addition, the Credit Facility restricts payments of dividends and distributions on shares in excess of 95% of the Company's funds from operations (FFO) except to the extent necessary to enable the Company to continue to qualify as a REIT for Federal income tax purposes. The Company had no borrowings under the 2018 Credit Facility as of and during the nine-month period ended September 30, 2018. As of September 30, 2017, the Company had $178.0 million of borrowings under the Credit Facility and $13.5 million in letters of credit outstanding. During the nine months ended September 30, 2017, the weighted-average interest rate on Credit Facility borrowings was 2.34%. As of September 30, 2017, the effective interest rate on Credit Facility borrowings was 2.43%. Concurrently with its entry into the 2018 Credit Facility, the Company terminated its then existing unsecured revolving credit facility, which had a scheduled maturity date of May 15, 2019. The Parent Company unconditionally guarantees the unsecured debt obligations of the Operating Partnership (or is a co-borrower with the Operating Partnership) but does not by itself incur unsecured indebtedness. The Parent Company has no material assets other than its investment in the Operating Partnership. The Company was in compliance with all financial covenants as of September 30, 2018. Management continuously monitors the Company’s current and anticipated compliance with the covenants. Certain of the covenants restrict the Company’s ability to obtain alternative sources of capital. As of September 30, 2018, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2018 (three months remaining) $ 1,854 2019 7,595 2020 87,226 2021 15,143 2022 256,332 Thereafter 1,585,346 Total principal payments 1,953,496 Net unamortized premiums/(discounts) (6,031 ) Net deferred financing costs (9,928 ) Outstanding indebtedness $ 1,937,537

Fair Value of Financial Instrum

Fair Value of Financial Instruments	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	7. FAIR VALUE OF FINANCIAL INSTRUMENTS Financial assets and liabilities recorded on the consolidated balance sheets are categorized based on the inputs to the valuation techniques as follows: • Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has the ability to access; • Level 2 inputs are inputs, other than quoted prices included in Level 1, which are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals; and • Level 3 inputs are unobservable inputs for the asset or liability, which is typically based on an entity’s own assumptions, as there is little, if any, related market activity or information. The Company determined the fair values disclosed below using available market information and discounted cash flow analyses as of September 30, 2018 and December 31, 2017, respectively. The discount rate used in calculating fair value is the sum of the c urrent risk free rate and the risk premium on the date of measurement of the instruments or obligations. Considerable judgment is necessary to interpret market data and to develop the related estimates of fair value. Accordingly, the estimates presented ar e not necessarily indicative of the amounts that the Company could realize upon disposition. The use of different estimates and valuation methodologies may have a material effect on the fair value amounts shown. The Company believes that the carrying amoun ts reflected in the consolidated balance sheets at September 30, 2018 and December 31, 2017 approximate the fair values for cash and cash equivalents, accounts receivable, other assets (except for the note receivable disclosed below), accounts payable an d accrued expenses. The following are financial instruments for which the Company’s estimates of fair value differ from the carrying amounts (in thousands): September 30, 2018 December 31, 2017 Carrying Amount (a) Fair Value Carrying Amount (a) Fair Value Unsecured notes payable $ 1,287,661 $ 1,249,225 $ 1,286,573 $ 1,314,900 Variable rate debt $ 327,288 $ 310,640 $ 327,039 $ 308,872 Mortgage notes payable $ 322,588 $ 314,813 $ 317,216 $ 304,665 Notes receivable (b) $ 47,821 $ 47,858 $ 3,532 $ 3,605 (a) T (b) The inputs to originate the notes receivable are unobservable and, as a result, are categorized as Level 3. The Company determined fair value by calculating the present value of the cash payments to be received through the maturity date of the loans. On June 26, 2018, the Company provided a $44.4 million mortgage loan to Brandywine 1919 Ventures, an unconsolidated real estate venture in which the Company holds a 50% ownership interest, and recorded a note receivable of $44.4 million. For additional information regarding the transaction, see Note 4, “Investment in Unconsolidated Real Estate Ventures.” As of September 30, 2018, notes receivable also consisted of a $3.4 million note receivable that was provided to a third party to acquire a property. The mortgage bears interest at 7.0% through March 2019 and 8.0% interest thereafter until its maturity date in March of 2020. The loan principal amortizes down to the balloon payment of $3.1 million which the Company expects to receive at maturity of the note in March of 2020. The Company periodically assesses collectability of the notes receivable in accordance with the accounting standard for loan receivables. As of September 30, 2018, the Company’s notes receivable are collectible. The inputs utilized to determine the fair value of the Company’s unsecured notes payable are categorized as Level 2. This is because the Company valued these instruments using quoted market prices as of September 30, 2018 and December 31, 2017. For the fair value of the Company’s unsecured notes, the Company uses a discount rate based on the indicative new issue pricing provided by lenders. The inputs utilized to determine the fair value of the Company’s mortgage notes payable and variable rate debt are categorized as Level 3. The fair value of the variable rate debt was estimated using a discounted cash flow analysis valuation on the borrowing rates currently available to the Company for loans with similar terms and maturities, as applicable. The fair value of the mortgage debt was determined by discounting the future contractual interest and principal payments by a blended market rate for loans with similar terms, maturities and loan-to-value. These inputs have been categorized as Level 3 because the Company considers the rates used in the valuation techniques to be unobservable inputs. The inputs to originate the notes receivable are unobservable and, as a result, are categorized as Level 3 . The Company determined fair value by calculating the present value of the cash payments to be received through the maturity dates of the loans. For the Company’s mortgage loans, the Company uses an estimate based discounted cash flow analyses and its knowledge of the mortgage market. An increase in the discount rate used in the discounted cash flow model would result in a decrease to the fair value of the Company’s long-term debt. Conversely, a decrease in the discount rate used in the discounted cash flow model would result in an increase to the fair value of the Company’s long-term debt. Disclosure about the fair value of financial instruments is based upon pertinent information available to management as of September 30, 2018 and December 31, 2017. Although management is not aware of any factors that would significantly affect the fair value amounts, such amounts have not been comprehensively revalued for purposes of these financial statements since September 30, 2018, and current estimates of fair value may differ from the amounts presented herein.

Limited Partners' Non-Controlli

Limited Partners' Non-Controlling Interests in the Parent Company	9 Months Ended
	Sep. 30, 2018
Noncontrolling Interest [Abstract]
LIMITED PARTNERS' NON-CONTROLLING INTERESTS IN THE PARENT COMPANY	8. LIMITED PARTNERS' NON-CONTROLLING INTERESTS IN THE PARENT COMPANY Non-controlling interests in the Parent Company’s financial statements relate to redeemable common limited partnership interests in the Operating Partnership held by parties other than the Parent Company and properties which are consolidated but not wholly owned. Operating Partnership The aggregate book value of the non-controlling interests associated with the redeemable common limited partnership interests in the accompanying consolidated balance sheet of the Parent Company was $14.7 million and $15.2 million as of September 30, 2018 and December 31, 2017, respectively. Under the applicable accounting guidance, the redemption value of limited partnership units are carried at, on a limited partner basis, the greater of historical cost adjusted for the allocation of income and distributions or fair value. The Parent Company believes that the aggregate settlement value of these interests, based on the number of units outstanding and the closing price of the common shares on the balance sheet dates as of September 30, 2018 and December 31, 2017, was approximately $23.3 million and $26.9 million, respectively.

Fair Value of Derivative Financ

Fair Value of Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
FAIR VALUE OF DERIVATIVE FINANCIAL INSTRUMENTS	9. FAIR VALUE OF DERIVATIVE FINANCIAL INSTRUMENTS The following table summarizes the terms and fair values of the Company’s derivative financial instruments as of September 30, 2018 and December 31, 2017. The notional amounts provide an indication of the extent of the Company’s involvement in these instruments at that time, but do not represent exposure to credit, interest rate or market risks (amounts presented in thousands and included in other assets and other liabilities on the Company’s consolidated balance sheets). Hedge Product Hedge Type Designation Notional Amount Strike Trade Date Maturity Date Fair value 9/30/2018 12/31/2017 9/30/2018 12/31/2017 Assets Swap Interest Rate Cash Flow (a) $ 250,000 $ 250,000 3.718 % October 8, 2015 October 8, 2022 $ 12,178 $ 5,694 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 546 25 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 277 59 $ 301,548 $ 301,548 (a) Hedging unsecured variable rate debt. The Company measures its derivative instruments at fair value and records them in the “Other assets” and (“Other liabilities”) captions on the Company’s consolidated balance sheets. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by itself and its counterparties. The Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that the inputs utilized to determine the fair value of derivative instruments are classified in Level 2 of the fair value hierarchy.

Beneficiaries Equity of the Par

Beneficiaries Equity of the Parent Company	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
BENEFICIARIES' EQUITY OF THE PARENT COMPANY	10. BENEFICIARIES’ EQUITY OF THE PARENT COMPANY Earnings per Share (EPS) The following tables detail the number of shares and net income used to calculate basic and diluted earnings per share (in thousands, except share and per share amounts; results may not add due to rounding): Three-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income (loss) $ (43,262 ) $ (43,262 ) $ 19,046 $ 19,046 Net (income) loss attributable to noncontrolling interests 339 339 (170 ) (170 ) Nonforfeitable dividends allocated to unvested restricted shareholders (80 ) (80 ) (73 ) (73 ) Net income (loss) attributable to common shareholders $ (43,003 ) $ (43,003 ) $ 18,803 $ 18,803 Denominator Weighted-average shares outstanding 178,602,622 178,602,622 175,433,657 175,433,657 Contingent securities/Share based compensation - - - 1,401,365 Weighted-average shares outstanding 178,602,622 178,602,622 175,433,657 176,835,022 Earnings (loss) per Common Share: Net income (loss) attributable to common shareholders $ (0.24 ) $ (0.24 ) $ 0.11 $ 0.11 Nine-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 14,579 $ 14,579 $ 48,015 $ 48,015 Net income attributable to noncontrolling interests (167 ) (167 ) (384 ) (384 ) Nonforfeitable dividends allocated to unvested restricted shareholders (280 ) (280 ) (245 ) (245 ) Distribution to preferred shareholders - - (2,032 ) (2,032 ) Preferred share redemption charge - - (3,181 ) (3,181 ) Net income attributable to common shareholders $ 14,132 $ 14,132 $ 42,173 $ 42,173 Denominator Weighted-average shares outstanding 178,515,993 178,515,993 175,315,581 175,315,581 Contingent securities/Share based compensation - 1,236,551 - 1,283,751 Weighted-average shares outstanding 178,515,993 179,752,544 175,315,581 176,599,332 Earnings per Common Share: Net income attributable to common shareholders $ 0.08 $ 0.08 $ 0.24 $ 0.24 Redeemable common limited partnership units totaling 1,479,799 at both September 30, 2018 and September 30, 2017, were excluded from the diluted earnings per share computations because they are not dilutive. Unvested restricted shares are considered participating securities which require the use of the two-class method for the computation of basic and diluted earnings per share. For the three- and nine-month periods ended September 30, 2018 and 2017, earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted shares issued to the Company’s executives and other employees under the Company's shareholder-approved long-term incentive plan. Common Shares On September 11, 2018, the Parent Company declared a distribution of $0.18 per common share, totaling $32.5 million, which was paid on October 18, 2018 to shareholders of record as of October 4, 2018. Preferred Shares Of the 20,000,000 preferred shares authorized, none were outstanding as of September 30, 2018 or September 30, 2017.

Partners Equity of The Operatin

Partners Equity of The Operating Partnership	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
PARTNERS' EQUITY OF THE OPERATING PARTNERSHIP	11. PARTNERS’ EQUITY OF THE OPERATING PARTNERSHIP Earnings per Common Partnership Unit The following tables detail the number of units and net income used to calculate basic and diluted earnings per common partnership unit (in thousands, except unit and per unit amounts; results may not add due to rounding): Three-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income (loss) $ (43,262 ) $ (43,262 ) $ 19,046 $ 19,046 Net income attributable to noncontrolling interests (20 ) (20 ) (12 ) (12 ) Nonforfeitable dividends allocated to unvested restricted unitholders (80 ) (80 ) (73 ) (73 ) Net income (loss) attributable to common unitholders $ (43,362 ) $ (43,362 ) $ 18,961 $ 18,961 Denominator Weighted-average units outstanding 180,082,421 180,082,421 176,913,456 176,913,456 Contingent securities/Share based compensation - - - 1,401,365 Total weighted-average units outstanding 180,082,421 180,082,421 176,913,456 178,314,821 Earnings (loss) per Common Partnership Unit: Net income (loss) attributable to common unitholders $ (0.24 ) $ (0.24 ) $ 0.11 $ 0.11 Nine-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 14,579 $ 14,579 $ 48,015 $ 48,015 Net income attributable to noncontrolling interests (46 ) (46 ) (25 ) (25 ) Nonforfeitable dividends allocated to unvested restricted unitholders (280 ) (280 ) (245 ) (245 ) Preferred unit dividends - - (2,032 ) (2,032 ) Preferred unit redemption charge - - (3,181 ) (3,181 ) Net income attributable to common unitholders $ 14,253 $ 14,253 $ 42,532 $ 42,532 Denominator Weighted-average units outstanding 179,995,792 179,995,792 176,795,380 176,795,380 Contingent securities/Share based compensation - 1,236,551 - 1,283,751 Total weighted-average units outstanding 179,995,792 181,232,343 176,795,380 178,079,131 Earnings per Common Partnership Unit Net income attributable to common unitholders $ 0.08 $ 0.08 $ 0.24 $ 0.24 Unvested restricted units are considered participating securities which require the use of the two-class method for the computation of basic and diluted earnings per share. For the three- and nine-month periods ended September 30, 2018 and 2017, earnings representing nonforfeitable dividends as noted in the table above were allocated to the unvested restricted units issued to the Parent Company in connection with awards to the Parent Company’s executives and other employees under the Parent Company's shareholder-approved long-term incentive plan. Common Partnership Units On September 11, 2018, the Operating Partnership declared a distribution of $0.18 per common partnership unit, totaling $32.5 million, which was paid on October 18, 2018 to unitholders of record as of October 4, 2018. Preferred Mirror Partnership Units Of the 20,000,000 units authorized, none were outstanding as of September 30, 2018 or September 30, 2017.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
SEGMENT INFORMATION	12. SEGMENT INFORMATION As of September 30, 2018, the Company owns and manages properties within five segments: (1) Philadelphia Central Business District (Philadelphia CBD), (2) Pennsylvania Suburbs, (3) Metropolitan Washington, D.C., (4) Austin, Texas and (5) Other. The Philadelphia CBD segment includes properties located in the City of Philadelphia in Pennsylvania. The Pennsylvania Suburbs segment includes properties in Chester, Delaware, and Montgomery counties in the Philadelphia suburbs. The Metropolitan Washington, D.C. segment includes properties in the District of Columbia, Northern Virginia and southern Maryland. The Austin, Texas segment includes properties in the City of Austin, Texas. The Other segment includes properties located in Camden County in New Jersey and properties in New Castle County in Delaware. In addition to the five segments, the corporate group is responsible for cash and investment management, development of certain real estate properties during the construction period, and certain other general support functions. Land held for development and construction in progress is transferred to operating properties by region upon completion of the associated construction or project. The following tables provide selected asset information and results of operations of the Company's reportable segments (in thousands): Real estate investments, at cost: September 30, 2018 December 31, 2017 Philadelphia CBD $ 1,652,819 $ 1,643,296 Pennsylvania Suburbs 979,068 958,796 Metropolitan Washington, D.C. (a) 539,105 978,257 Austin, Texas 170,912 163,653 Other 87,144 88,346 $ 3,429,048 $ 3,832,348 Assets held for sale (a) 396,072 - Operating properties $ 3,825,120 $ 3,832,348 Corporate Construction-in-progress $ 157,075 $ 121,188 Land held for development (b) $ 77,578 $ 98,242 Prepaid leasehold interests in land held for development, net (c) $ 40,100 $ - (a) As of September 30, 2018, eight office properties in the Metropolitan Washington, D.C. segment were classified as held for sale. See Note 3, “Real Estate Investments,” for further information. (b) As of September 30, 2018, the Company categorized 37.9 acres of land held for development, comprised of 2.7 acres and 35.2 acres, located in the Pennsylvania Suburbs segment and Other segment, respectively, as held for sale in accordance with applicable accounting standards for long lived assets. As of December 31, 2017, the Company categorized 13.1 acres of land held for development, located in the Other segment, as held for sale in accordance with applicable accounting standards for long lived assets. (c) As of September 30, 2018, this caption comprised leasehold interests in prepaid 99-year ground leases at 3025 and 3001-3003 JFK Boulevard, in Philadelphia, Pennsylvania. See Note 3, “Real Estate Investments,” Net operati ng income (in thousands): Three-month periods ended September 30, 2018 2017 Total revenue Operating expenses (a) Net operating income (loss) Total revenue Operating expenses (a) Net operating income Philadelphia CBD $ 64,352 $ (24,427 ) $ 39,925 $ 56,452 $ (22,010 ) $ 34,442 Pennsylvania Suburbs 34,745 (11,937 ) 22,808 34,861 (11,846 ) 23,015 Metropolitan Washington, D.C. 22,754 (8,548 ) 14,206 23,079 (8,500 ) 14,579 Austin, Texas 8,641 (3,894 ) 4,747 7,886 (3,929 ) 3,957 Other 3,707 (2,436 ) 1,271 3,752 (2,647 ) 1,105 Corporate 799 (1,636 ) (837 ) 2,408 (1,769 ) 639 Operating properties $ 134,998 $ (52,878 ) $ 82,120 $ 128,438 $ (50,701 ) $ 77,737 Nine-month periods ended September 30, 2018 2017 Total revenue Operating expenses (a) Net operating income (loss) Total revenue Operating expenses (a) Net operating income Philadelphia CBD $ 190,478 $ (73,559 ) $ 116,919 $ 165,352 $ (64,311 ) $ 101,041 Pennsylvania Suburbs 103,960 (37,018 ) 66,942 105,673 (35,670 ) 70,003 Metropolitan Washington, D.C. 69,012 (25,699 ) 43,313 69,190 (26,347 ) 42,843 Austin, Texas 25,474 (10,812 ) 14,662 25,772 (11,634 ) 14,138 Other 13,187 (9,601 ) 3,586 14,274 (9,083 ) 5,191 Corporate 3,031 (5,240 ) (2,209 ) 6,888 (5,355 ) 1,533 Operating properties $ 405,142 $ (161,929 ) $ 243,213 $ 387,149 $ (152,400 ) $ 234,749 (a) Includes property operating expenses, real estate taxes and third party management expense. Unconsolidated real estate ventures (in thousands): Investment in real estate ventures, at equity Equity in income (loss) of real estate venture As of Three-month periods ended September 30, Nine-month periods ended September 30, September 30, 2018 December 31, 2017 2018 2017 2018 2017 Philadelphia CBD $ 20,544 $ 39,939 $ (36 ) $ 134 $ (183 ) $ 113 Pennsylvania Suburbs - 3,503 - 24 - 448 Metropolitan Washington, D.C. 119,032 119,817 (31 ) (5,264 ) (431 ) (4,872 ) Austin, Texas 14,411 13,973 423 (15 ) 1,156 1,266 MAP Venture (a) 11,939 15,450 (444 ) (706 ) (2,011 ) (2,610 ) Other 1,856 1,939 89 104 287 268 Total $ 167,782 $ 194,621 $ 1 $ (5,723 ) $ (1,182 ) $ (5,387 ) (a) The MAP Venture represents a joint venture, formed on February 4, 2016 between the Company and MAP Ground Lease Holdings LLC, an affiliate of Och-Ziff Capital Management Group, LLC. The MAP Venture’s business operations, including properties in Richmond, Virginia; Metropolitan Washington, D.C.; New Jersey/Delaware and Pennsylvania Suburbs, are centrally managed with the results reported to management of the Company on a consolidated basis. As a result, the investment in the MAP Venture is separately presented. All other unconsolidated real estate ventures are managed consistently with the Company’s regional segments. Net operating income (“NOI”) is a non-GAAP financial measure defined as total revenue less property operating expenses, real estate taxes and third party management expenses. Property operating expenses that are included in determining NOI consist of costs that are necessary and allocable to our operating properties such as utilities, property-level salaries, repairs and maintenance, property insurance, management fees and bad debt expense. General and administrative expenses that are not reflected in NOI primarily consist of corporate-level salaries, amortization of share awards and professional fees that are incurred as part of corporate office management. All companies may n ot calculate NOI in the same manner. NOI is the measure that is used by the Company’s management to evaluate the operating performance of the Company’s real estate assets by segment. The Company believes NOI provides useful information to investors regardi ng the financial condition and results of operations because it reflects only those income and expense items that are incurred at the property level. While NOI is a relevant and widely used measure of operating performance of real estate investment trusts, it does not represent cash flow from operations or net income as defined by GAAP and should not be considered as an alternative to those measures in evaluating our liquidity or operating performance. NOI does not reflect interest expenses, real estate imp airment losses, depreciation and amortization costs, capital expenditures and leasing costs. The Company believes that net income (loss), as defined by GAAP, is the most appropriate earnings measure. The following is a reconciliation of consolidated net in come, as defined by GAAP, to consolidated NOI, (in thousands): Three-month periods ended September 30, Nine-month periods ended September 30, 2018 2017 2018 2017 Net income (loss) $ (43,262 ) $ 19,046 $ 14,579 $ 48,015 Plus: Interest expense 19,257 19,732 58,091 61,473 Interest expense - amortization of deferred financing costs 618 577 1,872 1,807 Depreciation and amortization 43,900 42,429 130,908 132,584 General and administrative expenses 5,963 5,813 22,209 21,797 Equity in (income) loss of Real Estate Ventures (1 ) 5,723 1,182 5,387 Provision for impairment 56,865 - 56,865 3,057 Less: Interest income 1,220 79 2,564 635 Income tax (provision) benefit - 793 (158 ) 1,032 Net gain (loss) on disposition of real estate - - (35 ) 8,411 Net gain on sale of undepreciated real estate - 953 2,859 953 Net gain on Real Estate Venture transactions - 13,758 37,263 28,340 Consolidated net operating income $ 82,120 $ 77,737 $ 243,213 $ 234,749

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	13. COMMITMENTS AND CONTINGENCIES Legal Proceedings The Company is involved from time to time in litigation on various matters, including disputes with tenants, vendors and disputes arising out of agreements to purchase or sell properties. Given the nature of the Company’s business activities, these lawsuits are considered routine to the conduct of its business. The result of any particular lawsuit cannot be predicted, because of the very nature of litigation, the litigation process and its adversarial nature, and the jury system. The Company will establish reserves for specific legal proceedings when it determines that the likelihood of an unfavorable outcome is probable and when the amount of loss is reasonably estimable. The Company does not expect that the liabilities, if any, that may ultimately result from such legal actions will have a material adverse effect on the consolidated financial position, results of operations or cash flows of the Company. Letters-of-Credit Under certain mortgages, including mortgages held by Real Estate Ventures, the Company may be required to fund required leasing and capital reserve accounts for the benefit of the mortgage lenders with a letter-of-credit. There were no associated letters-of-credit for a mortgage lender on September 30, 2018. Certain of the tenant rents at properties that secure these mortgage loans are deposited into the loan servicer’s depository accounts, which are used to fund debt service, operating expenses, capital expenditures and the escrow and reserve accounts, as necessary. Any excess cash is included in cash and cash equivalents. Environmental As an owner of real estate, the Company is subject to various environmental laws of federal, state, and local governments. The Company’s compliance with existing laws has not had a material adverse effect on its financial condition and results of operations, and the Company does not believe it will have a mat erial adverse effect in the future. However, the Company cannot predict the impact of unforeseen environmental contingencies or new or changed laws or regulations on its current Properties or on properties that the Company may acquire. Ground Rent Future minimum rental payments by the Company under the terms of all non-cancelable ground leases of land on which properties in the Company’s consolidated portfolio are situated are expensed on a straight-line basis regardless of when payments are due. The Company’s ground leases, excluding prepaid ground leases, have remaining lease terms ranging from 10 to 66 years. Minimum future rental payments on non-cancelable leases at September 30, 2018 are as follows (in thousands): Year Minimum Rent 2018 (three months remaining) $ 306 2019 1,222 2020 1,222 2021 1,222 2022 1,222 Thereafter 56,911 Total $ 62,105 The Company obtained ground tenancy rights related to three properties in Philadelphia, Pennsylvania, which provide for contingent rent participation by the lessor in certain capital transactions and net operating cash flows of the properties after certain returns are achieved by the Company. Such amounts, if any, will be reflected as contingent rent when incurred. The leases also provide for payment by the Company of certain operating costs relating to the land, primarily real estate taxes. The above schedule of future minimum rental payments does not include any contingent rent amounts or any reimbursed expenses. Reference is made in our Annual Report on Form 10-K for the year ended December 31, 2017 for further detail regarding commitments and contingencies. Fair Value of Contingent Consideration On April 2, 2015, the Company purchased 618 Market Street in Philadelphia, Pennsylvania. The allocated purchase price included contingent consideration of $2.0 million payable to the seller upon commencement of development. The liability was initially recorded at fair value of $1.6 million and will accrete through interest expense to $2.0 million over the expected period until development is commenced. The fair value of this contingent consideration was determined using a probability weighted discounted cash flow model. The significant inputs to the discounted cash flow model were the discount rate and weighted probability scenarios. As the inputs are unobservable, the Company determined the inputs used to value this liability fall within Level 3 for fair value reporting. As of September 30, 2018, the liability had accreted to $1.9 million. As there were no significant changes to the inputs, the liability remains within Level 3 for fair value reporting. Debt Guarantees As of September 30, 2018, the Company’s unconsolidated real estate ventures had aggregate indebtedness of $664.2 million. These loans are generally mortgage or construction loans, most of which are non-recourse to the Company, except for customary recourse carve-outs. As of September 30, 2018, the loans for which the Company has provided recourse guarantees consist of the following: (i) a $0.4 million payment guarantee on a loan with a $4.2 million outstanding principal balance, provided to PJP VII and (ii) up to a $41.3 million payment guarantee on a $150.0 million loan provided to 4040 Wilson. Other Commitments or Contingencies On October 13, 2017, the Company acquired a leasehold interest in the office building known as One Drexel Plaza, in Philadelphia, Pennsylvania. In connection with the acquisition, the Company is required to spend no less than $8.0 million in capital improvements to the property. Funding related to this requirement had not yet begun as of September 30, 2018. The Company estimates that it will incur $37.3 million in excess of this funding requirement and expects to complete the redevelopment of One Drexel Plaza during the second quarter of 2020 at an estimated aggregate cost of $83.1 million, inclusive of the acquisition cost of $37.8 million. Also on October 13, 2017, the Company acquired a leasehold interest in the land parcel at 3001 Market Street in Philadelphia, Pennsylvania (“Drexel Square”). During the fourth quarter of 2017, the Company broke ground on the construction of a public park on the site, marking the commencement of construction at our Schuylkill Yards Project with Drexel. Under the terms of the Development Agreement with Drexel University, the Company has until July 2019 to complete development of Drexel Square. If the Company is unable to complete such development within this timeframe, it may be subject to damages under the Development Agreement. During the fourth quarter of 2017, in connection with the Schuylkill Yards Project, the Company entered into a neighborhood engagement program and, as of September 30, 2018, had $2.7 million of future contractual obligations. In addition, the Company estimates $0.7 million of potential additional contributions for which the Company is not currently contractually obligated. On July 1, 2016, the Company closed on the acquisition of 34.6 acres of land located in Austin, Texas known as the Garza Ranch, for a purchase price of $20.6 million. As of September 30, 2018, the Company sold three parcels containing 8.4 acres, 1.7 acres and 6.6 acres (of the 34.6 acres) to three unaffiliated third parties. In connection with the agreements of sale, the Company entered into a development agreement and related completion guarantee to construct certain infrastructure improvements to the land. Recognition of the sale of the land parcels was deferred until the improvements were substantially complete, which occurred during the second quarter of 2018. “Basis of Presentation,” On December 3, 2015, the Company entered into an agreement to construct an 83,000 square foot build-to-suit service center (the “Subaru NSTC Development”) on land parcels owned by the Company for Subaru as the single tenant. On such date, Subaru entered into an 18-year lease for the service center. The lease contains a purchase option, which allows Subaru to purchase the property at commencement of the lease, or five years subsequent to inception, at depreciated cost. On May 18, 2018, Subaru exercised its option to purchase the property. The purchase price is equal to total project costs plus an 8% developer profit, as per the lease agreement. The closing date will be the later of: (i) 30 days following substantial completion of the project, and (ii) three business days following the completion of punch list items. At September 30, 2018, $34.5 million of the estimated project costs, totaling $47.6 million, had been funded, and is included within the “Other assets” caption of the consolidated balance sheets. The Company invests in its properties and regularly incurs capital expenditures in the ordinary course of business to maintain the properties. The Company believes that such expenditures enhance its competitiveness. The Company also enters into construction, utility and service contracts in the ordinary course of business which may extend beyond one year. These contracts typically provide for cancellation with insignificant or no cancellation penalties.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	14. SUBSEQUENT EVENTS On October 16, 2018, the Company entered into an agreement to sell a portfolio of eight properties containing an aggregate of 1,293,197 square feet, located in the Metropolitan Washington, D.C. segment, for a gross sales price of $312.0 million. The Company will retain a 15% ownership interest in the properties through an unconsolidated real estate venture. After obtaining debt financing for the real estate venture, the Company anticipates receiving net cash receipts of approximately $292.0 million. As of September 30, 2018, the Portfolio was classified as held sale and the Company recorded an impairment of $56.9 million. As the properties were impaired to reflect the value of the estimated net cash proceeds, the Company does not anticipate a gain or loss upon settlement, which is expected to occur during the fourth quarter of 2018. For further information related to the impact to the consolidated balance sheets, see the “ Held for Sale Real Estate Investments On October 17, 2018, the Company entered into an agreement to acquire its partner's entire 50% interest in the 12 remaining properties within the DRA Austin real estate venture, containing 1,570,123 square feet, located in Austin, Texas, for a gross sales price of $537.0 million. In connection with the acquisition, the Company will assume an estimated $245.8 million of mortgage debt. The Company expects the transaction to settle during the fourth quarter of 2018. As of September 30, 2018, the Company’s investment in the real estate venture is $14.4 million, and upon settlement, the Company expects to recognize a gain on the transaction, which will be reflected in the caption ‘Net gain on real estate transactions’ in its consolidated statements of operations.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The consolidated financial statements have been prepared by the Company pursuant to the rules and regulations of the U.S. Securities and Exchange Commission (“SEC”) for interim financial statements. Certain information and footnote disclosures normally included in the annual financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been condensed or omitted pursuant to such rules and regulations. In the opinion of management, all adjustments consist solely of normal recurring matters, and result in a fair statement of the financial position of the Company as of September 30, 2018, the results of its operations for the three- and nine-month periods ended September 30, 2018 and 2017 and its cash flows for the nine-month periods ended September 30, 2018 and 2017 have been included. The results of operations for such interim periods are not necessarily indicative of the results for a full year. These consolidated financial statements should be read in conjunction with the Parent Company’s and the Operating Partnership’s consolidated financial statements and footnotes included in their combined 2017 Annual Report on Form 10-K filed with the SEC on February 23, 2018. The Company's Annual Report on Form 10-K for the year ended December 31, 2017 contains a discussion of our significant accounting policies under Note 2, "Summary of Significant Accounting Policies".
Out of Period Adjustment	Out of Period Adjustment The Company recorded $1.2 million of impairment charges during the quarter ended December 31, 2016, which should have been recorded in the consolidated financial statements for the nine-month period ended September 30, 2017 and the year ended December 31, 2017. Management concluded that these misstatements were not material to any prior period, nor were they material to the consolidated financial statements as of and for the twelve-month periods ended December 31, 2017 and 2016.
Reclassifications	Through the three- and nine-month periods ended September 30, 2017, the Company included $0.8 million and $1.0 million of income tax benefit in general and administrative expenses, respectively. During the fourth quarter of 2017, the Company began disaggregating our income tax provision/benefit in the consolidated statements of operations. As a result, in the statements of operations for the three- and nine-month periods ended September 30, 2017, included herein, the Company reclassified $0.8 million and $1.0 million of net income tax benefit out of general and administrative expenses into the “Income tax (provision) benefit” caption in the consolidated statements of operations to provide comparative presentation.
Restricted Cash	During the first quarter of 2018, the Company adopted Financial Accounting Standards Board (the “FASB”) ASU No. 2016-18 requires that the statement of cash flows explain the change during the period in the total of cash, cash equivalents and amounts described as restricted cash or cash equivalents. Beginning-of-period and end-of-period total amounts shown on the statement of cash flows should include restricted cash, cash equivalents and amounts described as restricted cash or cash equivalents. The guidance does not define restricted cash or restricted cash equivalents. As of September 30, 2018 and September 30, 2017, the Company had $0.8 million and $1.3 million of restricted cash, respectively, on its consolidated balance sheets within the caption ‘Other assets.’ As a result of the adoption of this ASU, restricted cash balances are included with cash and cash equivalents balances as of the beginning and end of each period presented in the consolidated statements of cash flows. Separate line items reconciling changes in restricted cash balances to the changes in cash and cash equivalents will no longer be presented within the operating and investing sections of the consolidated statements of cash flows. As a result of the adoption of ASU 2016-18, for the nine-months ended September 30, 2017 operating cash flows increased by $0.6 million, which is reflected within the change in other assets caption .
Revenue Recognition	In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). Under Topic 606, revenue is recognized when a customer obtains control of promised goods or services and is recognized at an amount that reflects the consideration expected to be received in exchange for such goods or services. In addition, Topic 606 requires disclosure of the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers. The Company adopted Topic 606 in the first quarter of 2018 using the modified retrospective method. This adoption, which required us to evaluate incomplete contracts as of January 1, 2018, related to the Company’s point of sale revenue, management, leasing and development fee arrangements and other sundry income. The Company’s analysis of incomplete contracts resulted in no restatement of the consolidated balance sheets and statements of operations presented in its consolidated financial statements. Results for reporting periods beginning after January 1, 2018 are presented under Topic 606. The new guidance provides a unified model to determine how revenue is recognized. To determine the proper amount of revenue to be recognized, the Company performs the following steps: (i) identify the contract with the customer, (ii) identify the performance obligations within the contract, (iii) determine the transaction price, (iv) allocate the transaction price to the performance obligations and (v) recognize revenue when (or as) a performance obligation is satisfied. The following is a summary of revenue earned by the Company’s reportable segments (see Note 12, “Segment Information,” Three-month period ended September 30, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate (a) Total Base rent $ 42,289 $ 29,116 $ 20,635 $ 5,008 $ 2,035 $ (492 ) $ 98,591 Straight-line rent 1,912 1,202 (492 ) (43 ) 65 (110 ) 2,534 Point of sale 5,905 73 287 134 56 - 6,455 Total rents 50,106 30,391 20,430 5,099 2,156 (602 ) 107,580 Tenant reimbursements 13,087 3,704 902 2,286 698 (120 ) 20,557 Termination fees 37 461 - - - - 498 Third party management fees, labor reimbursement and leasing 203 6 1,279 1,223 846 1,387 4,944 Other income 919 183 143 33 7 134 1,419 Total revenue $ 64,352 $ 34,745 $ 22,754 $ 8,641 $ 3,707 $ 799 $ 134,998 Nine-month period ended September 30, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate (a) Total Base rent $ 121,940 $ 88,929 $ 61,575 $ 14,442 $ 6,340 $ (1,464 ) $ 291,762 Straight-line rent 9,194 2,208 (645 ) 164 189 (345 ) 10,765 Point of sale 17,526 201 783 385 175 - 19,070 Total rents 148,660 91,338 61,713 14,991 6,704 (1,809 ) 321,597 Tenant reimbursements 37,585 10,795 2,687 6,258 2,124 (355 ) 59,094 Termination fees 192 1,300 138 - - - 1,630 Third party management fees, labor reimbursement and leasing 632 18 4,130 4,155 4,345 4,251 17,531 Other income 3,409 509 344 70 14 944 5,290 Total revenue $ 190,478 $ 103,960 $ 69,012 $ 25,474 $ 13,187 $ 3,031 $ 405,142 (a) Corporate includes intercompany eliminations necessary to reconcile to consolidated Company totals. Rental Revenue The Company owns, operates and manages commercial real estate. Rental revenue is earned by leasing commercial space to the Company’s tenants. Rental revenue is recognized on a straight-line basis over the term of the leases. The Company’s primary source of revenue is leases which fall under the scope of Leases (Topic 840). Point of Sale Revenue Point of sale revenue consists of parking and flexible stay revenue from the Company’s hotel operations. Point of sale service obligations are performed daily, and the customer obtains control of those services simultaneously as they are performed. Accordingly, revenue is recorded on an accrual basis as it is earned, coinciding with the services that are provided to the Company’s customers. Due to the nature of the services provided to the Company’s customers, there is a nominal amount of unearned revenue recorded as deposits on the Company’s balance sheet related to its parking and flexible stay operations. Tenant Reimbursements The Company contracts with third-party vendors and suppliers for goods and services to fulfill certain of the Company’s obligations to tenants. The Company is reimbursed by tenants for these goods and services in the period that the expenses are incurred based on the terms of the lease agreements with each tenant. Third party management fees, labor reimbursement and leasing The Company performs property management services for third-party property owners of real estate that consist of: (i) providing leasing services, (ii) property inspections, (iii) repairs and maintenance monitoring, and (iv) financial and accounting oversight. For these services, the Company earns management fees monthly, which are based on a fixed percentage of each managed property’s financial results, and is reimbursed for the labor costs incurred by its property management employees as services are rendered to the property owners. The Company determined that control over the services is passed to its customers simultaneously as performance occurs. Accordingly, management fee revenue is earned as the services are provided to the Company’s customers. Lease commissions are earned when the Company, as a broker for the third party property owner, executes a lease agreement with a tenant. Based on the terms of the Company’s lease commission contracts, it determined that control is transferred to the customer upon execution of each lease agreement. The Company’s lease commissions are earned based on a fixed percentage of rental income generated for each executed lease agreement and there is no variable income component. Development fee revenue is earned through two different sources: (i) the Company performs development services for third parties as agent and earns fixed development fees based on a percentage of construction costs incurred over the construction period, and (ii) the Company acts as a general contractor on behalf of one of its managed real estate ventures. The Company acts as the principal construction company for the real estate venture and records gross revenue as it provides construction services based on the quantifiable construction outputs. In applying the cost based output method of revenue recognition, the Company uses the actual costs incurred relative to the total estimated costs to determine its progress towards contract completion and to calculate the corresponding gross revenue and gross profit to recognize. For any costs that do not contribute to satisfying the Company’s performance obligations, it excludes such costs from its output methods of revenue recognition as the amounts are not reflective of transferring control of the outputs to the customer. The use of estimates in this calculation involves significant judgment. Other Income Other income primarily consists of sundry revenue earned for services provided to tenants. Sundry revenues are recognized simultaneously with the services provided to the Company’s tenants. Contract assets and contract liabilities As of September 30, 2018, the Company has no outstanding assets or liabilities associated with the Company’s third party management contracts.
Fair Value Measurements	Nonfinancial Assets In February 2017, the FASB issued ASU No. 2017-05, Gains and losses from the derecognition of nonfinancial assets (ASC 610-20), to provide guidance for recognizing gains and losses from the transfer of nonfinancial assets and in-substance nonfinancial assets in contracts with non-customers, unless other specific guidance applies. The standard requires a company to derecognize nonfinancial assets once it transfers control of a distinct nonfinancial asset or distinct in-substance nonfinancial asset. Additionally, when a company transfers its controlling interest in a nonfinancial asset but retains a noncontrolling ownership interest, a company is required to measure any noncontrolling interest it receives or retains at fair value. The guidance requires companies to recognize a full gain or loss on the transaction. As a result of the new guidance, the previous guidance specific to real estate sales within ASC 360-20 will be eliminated. The Company adopted ASU 2017-05 in the first quarter of 2018 using the modified retrospective method. This adoption requires the Company to analyze incomplete contracts related to property dispositions previously accounted for under ASC 360-20 and to determine whether such arrangements had any forms of continuing involvement that may have affected the revenue or profit recognition of the transactions, including arrangements with prohibited forms of continuing involvement. The Company evaluated the following incomplete contracts to determine if the revenue recognition pattern was affected by ASU 2017-05: Garza Land Sales On July 1, 2016, the Company closed on the acquisition of 34.6 acres of land located in Austin, Texas known as the Garza Ranch, for a purchase price of $20.6 million. As of September 30, 2018, the These improvement costs were included in the sale price of each land parcel. he Company did not transfer control to the buyers of the land parcels and The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three-month period ended June 30, 2018, the infrastructure improvements were substantially completed. As a result, the Company transferred control of the land parcels to the buyers and recognized the land sales. Accordingly, during the three-month period ended June 30, 2018, the Company applied the cash proceeds received from the settlements of each parcel and recognized an aggregate $2.8 million deferred gain. There was no activity or gain recognized during the three-month period ended September 30, 2018. The following table details the gain on sale for each land parcel, as of September 30, 2018 (dollars, in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale March 16, 2018 Garza Ranch - Office Austin, TX 1 6.6 $ 14,571 $ 14,509 $ 1,424 April 28, 2017 Garza Ranch - Multifamily Austin, TX 1 8.4 11,800 11,560 1,233 January 30, 2017 Garza Ranch - Hotel Austin, TX 1 1.7 3,500 3,277 180 Total Dispositions 3 16.7 $ 29,871 $ 29,346 $ 2,837 Based on the facts and circumstances, revenue recognition under ASU 2017-05 coincides with the Company’s conclusion under ASC 360-20, and no restatement of the consolidated financial statements is necessary as a result of implementing the guidance for the sale of nonfinancial assets. Marine Piers Sublease Interest Sale On March 15, 2017, the Company sold its sublease interest in the Piers at Penn’s Landing (the “Marine Piers”), which includes leasehold improvements containing 181,900 net rentable square feet, and a marina, located in Philadelphia, Pennsylvania, for an aggregate sales price of $21.4 million. On the closing date, the buyer paid $12.0 million in cash and the Company received cash proceeds of $11.2 million, after closing costs and prorations. The $9.4 million balance of the purchase is due on (a) January 31, 2020, in the event that the tenant at the Marine Piers does not exercise an option it holds to extend the term of the sublease or (b) January 15, 2024, in the event that the tenant does exercise the option to extend the term of the sublease. In accordance with ASU 2017-05, the Company determined that it is appropriate to recognize the sale of the sublease interest in the Marine Piers and to defer the amount of the pending payment due from the buyer because the Company cannot determine the collectability of the remaining $9.4 million balance due under the purchase and sale agreement. The net book value of the Marine Piers was $4.7 million, resulting in a gain on sale of $6.5 million. The remaining gain on sale of $9.4 million arising from the pending payment will be recognized at the earlier of: (i) the time that the Company determines collection of the deferred payment is probable or (ii) on the second purchase price installment date. Based on the facts and circumstances, revenue recognition under ASU 2017-05 coincides with the Company’s previous conclusion under ASC 360-20, and therefore no restatement of the consolidated financial statements is necessary as a result of implementing the guidance for the sale of nonfinancial assets. Subaru National Training Center On December 3, 2015, the Company entered into an agreement to construct an 83,000 square foot build-to-suit service center (the “Subaru NSTC Development”) on land parcels owned by the Company for Subaru as the single tenant. Concurrently, Subaru entered into an 18-year lease for the service center. The lease is classified as a direct finance lease within the “Other assets” caption on the consolidated balance sheets. The lease contained a purchase option, which allowed Subaru to purchase the property at the commencement of the lease, or five years subsequent to inception, at depreciated cost. During the third quarter of 2018, the lease commenced and Subaru exercised its purchase option for the Subaru NSTC Development. Accordingly, the Company recognized $0.4 million in interest income during the three months ended September 30, 2018, in accordance with accounting guidance for sales-type leases.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2018, the FASB issued ASU No. 2018-07 that aligns the accounting for share-based payment awards issued to employees and nonemployees. Under previously issued GAAP guidance, the accounting for nonemployee share-based payments differed from that applied to employee awards, particularly with regard to the measurement date and the impact of performance conditions. Under the revised guidance, the existing employee guidance will apply to nonemployee share-based transactions (as long as the transaction is not effectively a form of financing), with the exception of specific guidance related to the attribution of compensation cost. The cost of nonemployee awards will continue to be recorded as if the grantor had paid cash for the goods or services. In addition, the contractual term will be able to be used in lieu of an expected term in the option-pricing model for nonemployee awards. Changes to the accounting for nonemployee awards include: • Equity-classified share-based payment awards issued to nonemployees will now be measured on the grant date, instead of the previous requirement to remeasure the awards through the performance completion date. • Compensation cost associated with the award will be recognized when achievement of the performance condition is probable, rather than upon achievement of the performance condition. • The current requirement to reassess the classification (equity or liability) for nonemployee awards upon vesting will be eliminated, except for awards in the form of convertible instruments. • The revised guidance also clarifies that any share-based payment awards issued to customers should be evaluated under ASC 606, Revenue from Contracts with Customers. The amendments in this update are effective for public business entities for fiscal years beginning after December 15, 2018, including interim periods within that fiscal year. Early adoption is permitted, but no earlier than an entity’s adoption date of Topic 606. The Company is in the process of evaluating the impact of this new guidance on its consolidated financial statements. In August 2017, the FASB issued ASU No. 2017-12 to simplify the application of hedge accounting guidance and improve the financial reporting of hedging relationships to better portray the economic results of an entity’s risk management activities in its financial statements. In addition, ASU 2017-12 requires an entity to present the earnings effect of the hedging instrument in the same income statement line item in which the earnings effect of the hedged item is reported. The transition guidance provides companies with the option of early adopting the new standard using a modified retrospective transition method in any interim period after issuance of the update or requires adoption for fiscal years beginning after December 15, 2018. This adoption method requires companies to recognize the cumulative effect of initially applying the guidance as an adjustment to accumulated other comprehensive income with a corresponding adjustment to the opening balance of retained earnings as of the beginning of the fiscal year that an entity adopts the update. The Company is in the process of evaluating the impact of this new guidance on its consolidated financial statements.
Leasing Standard	Leasing Standard In February 2016, the FASB issued guidance (“ASU-2016-02”) modifying the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). The new standard requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase by the lessee. This classification will determine whether lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease, respectively. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for in the same manner as operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. The guidance supersedes previously issued guidance under ASC Topic 840 “Leases.” The lease ASU requires the use of the modified retrospective transition method and does not allow for a full retrospective approach. However, it provides two options for application of the modified retrospective transition method: • Under the first option, the ASU requires the application of the standard to all leases that exist at or commence after, January 1, 2017 (the beginning of the earliest comparative period presented in the 2019 financial statements), with a cumulative adjustment to the opening balance of retained earnings on January 1, 2017, for the effect of applying the standard at the date of initial applications, and restatement of the amounts presented prior to January 1, 2019. • Under the second option, an entity may elect a package of practical expedients, which allows for the following: o An entity need not reassess whether any expired or existing contracts are or contain leases; o An entity need not reassess the lease classification for any expired or existing leases; and o An entity need not reassess initial direct costs for any existing leases. This package of practical expedients is available as a single election that must be consistently applied to all existing leases at the date of adoption. Lessors that adopt this package are not expected to reassess expired or existing leases at the date of initial application, which is January 1, 2017, under the ASU. This option enables entities to account for their existing leases for the remainder of the respective lease terms following previous accounting guidance, which eliminates the need to calculate a cumulative adjustment to the opening balance of retained earnings. In addition, there is a practical expedient that allows the Company to use hindsight when determining the lease term and assessing the fair value of right of use assets. After considering its impact, the Company has decided not to elect the hindsight expedient as part of the application of the modified retrospective transition method. Furthermore, in July 2018, the FASB adopted an amendment to the package of practical expedients that provides an optional transition method to make January 1, 2019 the initial application date of the ASU, rather than January 1, 2017. Entities that elect both the package of practical expedients and the optional transitional method will apply the new lease ASU prospectively, to leases commencing or modified after January 1, 2019, and will not be required to apply the disclosures under the new lease ASU to comparative periods. In January 2018, the FASB issued ASU No. 2018-01 to address the accounting treatment of land easements within the context of ASU No. 2016-02, Leases (Topic 842). ASU 2018-01 provides an optional transition practical expedient to not evaluate under Topic 842 existing or expired land easements that were not previously accounted for as leases under the current leases guidance in Topic 840. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. In July 2018, the FASB issued ASU No. 2018-11, an amendment to the lease ASU that will allow lessors to elect, as a practical expedient, not to allocate the total consideration to lease and nonlease components based on their relative standalone selling prices. This practical expedient will allow lessors to elect a combined single lease component presentation if: (i) the timing and pattern of the revenue recognition of the combined single lease component is the same, and (ii) the related lease component and, the combined single lease component would be classified as an operating lease. Nonlease components that do not meet the criteria of this practical expedient will be accounted for under the new revenue recognition ASU. The guidance is effective on January 1, 2019, with early adoption permitted. The ASU is expected to have the following impact on the Company’s consolidated financial statements: • Under ASC 842 as a lessor, lease components are recognized on a straight line basis, while non-lease components will be recognized in accordance with the new revenue standard. The Company is in the process of evaluating its leases to determine if the timing and pattern of recognition for its lease and nonlease components is the same. If it is determined that the pattern of revenue recognition is the same for lease and nonlease components then the Company will present them within rental revenue in its consolidated statement of operations. The Company is in the process of evaluating the impact the ASU will have on its consolidated financial statements. • ASC 842 is expected to impact the Company’s consolidated financial statements as the Company has land lease arrangements for which it is the lessee. Based on the Company’s evaluation, it expects operating expenses to increase by $0.8 million as ground rent expense for certain of its CPI indexed ground leases will be recognized on a straight-line basis under the new guidance. • The Company will expense additional costs related to leasing efforts under ASC 842 compared to the previous GAAP because certain activities performed by personnel involved in the leasing process will no longer be considered incremental costs to execute a lease agreement. Based on the Company’s analysis, leasing expenses will increase by $3.6 million for the year ended December 31, 2019, as internal costs and leasing pursuit costs will be expensed as incurred under ASC 842. • The Company’s equity-method investments may adopt the standard using the timeline otherwise afforded private companies. The Company anticipates the impact of ASC 842 will be similar to the items described above. The Company has not completed its analysis of this ASU. The Company expects tenant recoveries that qualify as nonlease components will be presented under a single lease component presentation. Tenant recoveries that qualify as lease components, which relate to the right to use the leased asset (e.g., property taxes, and insurance), will be accounted for under the new lease ASU. Tenant recoveries that qualify as nonlease components, which relate to payments for goods or services that are transferred separately from the right to use the underlying asset, including tenant recoveries pertaining to payments for maintenance activities and common area expenses, would be accounted for under the new revenue recognition ASU upon adoption of the new lease ASU. Additionally, the Company has determined that it is going to elect to apply the package of practical expedients when applying the modified retrospective approach.

Organization of the Parent Co_2

Organization of the Parent Company and The Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Core Portfolio of Operating Properties and Excludes Development and Redevelopment Properties Under Construction	The Company’s core portfolio of operating properties, as of September 30, 2018, excludes two development properties and five redevelopment properties under construction or committed for construction (collectively, the “Core Properties”). The Properties were comprised of the following as of September 30, 2018: Number of Properties Rentable Square Feet Office properties 73 13,673,405 Mixed-use properties 4 646,741 Retail properties 1 17,884 Core Properties 78 14,338,030 Development properties 2 247,818 Redevelopment properties 5 583,719 Held for sale properties (a) 8 1,293,197 The Properties 93 16,462,764 (a) As of September 30, 2018, eight office properties were classified as held for sale in the Company’s Metropolitan Washington, D.C. segment. See Note 3, “ Real Estate Investments

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 30, 2018
Summary of Revenue Earned by Reportable Segments	The following is a summary of revenue earned by the Company’s reportable segments (see Note 12, “Segment Information,” Three-month period ended September 30, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate (a) Total Base rent $ 42,289 $ 29,116 $ 20,635 $ 5,008 $ 2,035 $ (492 ) $ 98,591 Straight-line rent 1,912 1,202 (492 ) (43 ) 65 (110 ) 2,534 Point of sale 5,905 73 287 134 56 - 6,455 Total rents 50,106 30,391 20,430 5,099 2,156 (602 ) 107,580 Tenant reimbursements 13,087 3,704 902 2,286 698 (120 ) 20,557 Termination fees 37 461 - - - - 498 Third party management fees, labor reimbursement and leasing 203 6 1,279 1,223 846 1,387 4,944 Other income 919 183 143 33 7 134 1,419 Total revenue $ 64,352 $ 34,745 $ 22,754 $ 8,641 $ 3,707 $ 799 $ 134,998 Nine-month period ended September 30, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate (a) Total Base rent $ 121,940 $ 88,929 $ 61,575 $ 14,442 $ 6,340 $ (1,464 ) $ 291,762 Straight-line rent 9,194 2,208 (645 ) 164 189 (345 ) 10,765 Point of sale 17,526 201 783 385 175 - 19,070 Total rents 148,660 91,338 61,713 14,991 6,704 (1,809 ) 321,597 Tenant reimbursements 37,585 10,795 2,687 6,258 2,124 (355 ) 59,094 Termination fees 192 1,300 138 - - - 1,630 Third party management fees, labor reimbursement and leasing 632 18 4,130 4,155 4,345 4,251 17,531 Other income 3,409 509 344 70 14 944 5,290 Total revenue $ 190,478 $ 103,960 $ 69,012 $ 25,474 $ 13,187 $ 3,031 $ 405,142 (a) Corporate includes intercompany eliminations necessary to reconcile to consolidated Company totals.
Summary of Gain on Sale for Each Land Parcel	The Company sold the following office property during the nine-month period ended September 30, 2018 (dollars in thousands): Disposition Date Property/Portfolio Name Location Type Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Loss on Sale June 21, 2018 20 East Clementon Road Gibbsboro, NJ Office 1 38,260 $ 2,000 $ 1,850 $ (35 ) Total Dispositions 1 38,260 $ 2,000 $ 1,850 $ (35 ) The Company sold the following land parcels during the nine-month period ended September 30, 2018 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale March 16, 2018 Garza Ranch - Office Austin, TX 1 6.6 $ 14,571 $ 14,509 $ 1,424 (a) January 10, 2018 Westpark Land Durham, NC 1 13.1 485 412 22 Total Dispositions 2 19.7 $ 15,056 $ 14,921 $ 1,446 (a) As of March 31, 2018, the Company had not transferred control to the buyer of this land parcel, or two other parcels at this site which were sold during 2017, because of a completion guarantee which required the Company, as developer, to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three months ended June 30, 2018, the infrastructure improvements were substantially completed, at which time the Company transferred control of the land parcels. As a result, the Company then recognized the sale. See Note 2, “Basis of Presentation,” for further discussion of the infrastructure improvements and related revenue recognition
Land and Sale [Member]
Summary of Gain on Sale for Each Land Parcel	There was no activity or gain recognized during the three-month period ended September 30, 2018. The following table details the gain on sale for each land parcel, as of September 30, 2018 (dollars, in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale March 16, 2018 Garza Ranch - Office Austin, TX 1 6.6 $ 14,571 $ 14,509 $ 1,424 April 28, 2017 Garza Ranch - Multifamily Austin, TX 1 8.4 11,800 11,560 1,233 January 30, 2017 Garza Ranch - Hotel Austin, TX 1 1.7 3,500 3,277 180 Total Dispositions 3 16.7 $ 29,871 $ 29,346 $ 2,837

Real Estate Investments (Tables

Real Estate Investments (Tables)	9 Months Ended
	Sep. 30, 2018
Real Estate Properties [Line Items]
Gross Carrying Value Of Operating Properties	As of September 30, 2018 and December 31, 2017, the gross carrying value of the operating properties was as follows (in thousands): September 30, December 31, 2018 2017 Land $ 437,640 $ 492,197 Building and improvements 2,579,740 2,896,113 Tenant improvements 411,668 444,038 Operating properties 3,429,048 3,832,348 Assets held for sale - real estate investments 396,072 - Total $ 3,825,120 $ 3,832,348
Schedule of Purchase Price Allocation	The acquisition value has been allocated as follows (in thousands): January 5, 2018 Building, land and improvements $ 20,734 Intangible assets acquired (a) 3,144 Below market lease liabilities assumed (b) (182 ) Total unencumbered acquisition value $ 23,696 Mortgage debt assumed - at fair value (c) (9,940 ) Total encumbered acquisition value $ 13,756 Total unencumbered acquisition value 23,696 Mortgage debt assumed - at fair value (c) (9,940 ) Investment in unconsolidated real estate ventures (3,502 ) Net working capital assumed 1,379 Gain on real estate venture transactions $ 11,633 (a) (b) (c)
Summary of Gain on Sale for Each Land Parcel	The Company sold the following office property during the nine-month period ended September 30, 2018 (dollars in thousands): Disposition Date Property/Portfolio Name Location Type Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Loss on Sale June 21, 2018 20 East Clementon Road Gibbsboro, NJ Office 1 38,260 $ 2,000 $ 1,850 $ (35 ) Total Dispositions 1 38,260 $ 2,000 $ 1,850 $ (35 ) The Company sold the following land parcels during the nine-month period ended September 30, 2018 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale March 16, 2018 Garza Ranch - Office Austin, TX 1 6.6 $ 14,571 $ 14,509 $ 1,424 (a) January 10, 2018 Westpark Land Durham, NC 1 13.1 485 412 22 Total Dispositions 2 19.7 $ 15,056 $ 14,921 $ 1,446 (a) As of March 31, 2018, the Company had not transferred control to the buyer of this land parcel, or two other parcels at this site which were sold during 2017, because of a completion guarantee which required the Company, as developer, to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three months ended June 30, 2018, the infrastructure improvements were substantially completed, at which time the Company transferred control of the land parcels. As a result, the Company then recognized the sale. See Note 2, “Basis of Presentation,” for further discussion of the infrastructure improvements and related revenue recognition
Held for Sale Properties Included in Continuing Operations [Member]
Real Estate Properties [Line Items]
Summary of Properties Classified as Held for Sale but Which did not Meet the Criteria to be Classified within Discontinued Operations	The following is a summary of properties classified as held for sale but which did not meet the criteria to be classified within discontinued operations at September 30, 2018 (in thousands): Held for Sale Properties Included in Continuing Operations September 30, 2018 Metropolitan Washington, D.C. - Office (a) Pennsylvania Suburbs - Land (b) Other - Land (b) Total ASSETS HELD FOR SALE Real estate investments: Operating properties $ 396,072 $ - $ - $ 396,072 Accumulated depreciation (112,600 ) - - (112,600 ) Operating real estate investments, net 283,472 - - 283,472 Construction-in-progress 1,748 - - 1,748 Land inventory - 4,254 7,321 11,575 Total real estate investments 285,220 4,254 7,321 296,795 Other assets 399 - - 399 Total assets held for sale, net $ 285,619 $ 4,254 $ 7,321 $ 297,194 LIABILITIES HELD FOR SALE Other liabilities $ 826 $ - $ - $ 826 Total liabilities held for sale $ 826 $ - $ - $ 826 (a) As of September 30, 2018, the Company determined that the sale of eight office properties, containing 1,293,197 rentable square feet, in the Metropolitan Washington, D.C. segment, was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the $366.0 million carrying value of the properties exceeded the estimated $309.1 million fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $56.9 million during the three-month period ended September 30, 2018. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of ten years and residual capitalization rates and discount rates of 7.47% and 8.60%, respectively. The results were comparable to indicative pricing in the market. As significant inputs to the model are unobservable, the Company determined that the value determined for this property falls within Level 3 fair value reporting. (b) As of September 30, 2018, the Company determined that the sale of one land parcel in the Pennsylvania Suburbs segment and two parcels of land in the Other segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the fair value less the anticipated costs of sale of the properties exceeded the carrying values. As a result, the Company expects to record gains on sale. The fair value measurement will be based on the pricing in the purchase and sale agreements.

Investment in Unconsolidated _2

Investment in Unconsolidated Real Estate Ventures (Tables)	9 Months Ended
	Sep. 30, 2018
Equity Method Investments And Joint Ventures [Abstract]
Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss)	The following is a summary of the financial position of the Real Estate Ventures in which the Company held interests as of September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) (a) Other Total Net property $ 258,424 $ 157,824 $ - $ 504,652 $ 920,900 Other assets 39,398 23,133 - 83,835 146,366 Other liabilities 18,705 4,347 - 68,042 91,094 Debt, net 246,158 92,642 - 321,241 660,041 Equity (b) 32,959 83,968 - 199,204 316,131 December 31, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Net property $ 263,557 $ 158,960 $ 143,990 $ 517,458 $ 1,083,965 Other assets 42,272 24,181 8,563 86,916 161,932 Other liabilities 24,131 4,493 1,648 67,435 97,707 Debt, net 248,700 92,917 110,136 314,667 766,420 Equity (b) 32,998 85,731 40,769 222,272 381,770 (a) On January 10, 2018, HSRE-BDN I, LLC (evo at Cira Centre South) sold the 345-unit student housing tower, its sole operating asset. See ‘evo at Cira Disposition’ section below. (b) This amount includes the effect of the basis difference between the Company's historical cost basis and the basis recorded at the Real Estate Venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from the impairment of investments, purchases of third party interests in existing Real Estate Ventures and upon the transfer of assets that were previously owned by the Company into a Real Estate Venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the Real Estate Venture level. The following is a summary of results of operations of the Real Estate Ventures in which the Company held interests during the three- and nine-month periods ended September 30, 2018 and 2017 (in thousands): Three-month period ended September 30, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 14,232 $ 5,962 $ - $ 21,823 $ 42,017 Operating expenses (6,428 ) (2,589 ) - (12,123 ) (21,140 ) Interest expense, net (2,549 ) (873 ) - (4,122 ) (7,544 ) Depreciation and amortization (4,896 ) (2,232 ) - (6,135 ) (13,263 ) Loss on early extinguishment of debt - - - (334 ) (334 ) Net income (loss) $ 359 $ 268 $ - $ (891 ) $ (264 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 180 $ 134 $ - $ (550 ) $ (236 ) Basis adjustments and other 243 31 - (37 ) 237 Equity in income (loss) of Real Estate Ventures $ 423 $ 165 $ - $ (587 ) $ 1 Three-month period ended September 30, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 22,493 $ 8,438 $ 3,009 $ 22,571 $ 56,511 Operating expenses (10,107 ) (4,359 ) (841 ) (12,111 ) (27,418 ) Interest expense, net (3,784 ) (1,384 ) (1,097 ) (5,406 ) (11,671 ) Depreciation and amortization (9,334 ) (3,251 ) (1,128 ) (6,970 ) (20,683 ) Net loss $ (732 ) $ (556 ) $ (57 ) $ (1,916 ) $ (3,261 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net loss $ (366 ) $ (278 ) $ (29 ) $ (1,002 ) $ (1,675 ) Other-than-temporary impairment - (4,844 ) - - $ (4,844 ) Basis adjustments and other 351 (8 ) 53 400 796 Equity in income (loss) of Real Estate Ventures $ (15 ) $ (5,130 ) $ 24 $ (602 ) $ (5,723 ) Nine-month period ended September 30, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 42,492 $ 17,768 $ 995 $ 64,684 $ 125,939 Operating expenses (18,245 ) (8,010 ) (250 ) (35,492 ) (61,997 ) Interest expense, net (7,070 ) (2,606 ) (388 ) (13,558 ) (23,622 ) Depreciation and amortization (15,622 ) (6,915 ) (376 ) (18,526 ) (41,439 ) Loss on early extinguishment of debt - - (718 ) (334 ) (1,052 ) Net income (loss) $ 1,555 $ 237 $ (737 ) $ (3,226 ) $ (2,171 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 778 $ 119 $ (369 ) $ (1,946 ) $ (1,418 ) Basis adjustments and other 378 33 11 (186 ) 236 Equity in income (loss) of Real Estate Ventures $ 1,156 $ 152 $ (358 ) $ (2,132 ) $ (1,182 ) Nine-month period ended September 30, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 70,185 $ 23,751 $ 9,264 $ 66,409 $ 169,609 Operating expenses (29,119 ) (10,547 ) (2,232 ) (35,858 ) (77,756 ) Interest expense, net (11,217 ) (3,830 ) (3,009 ) (15,716 ) (33,772 ) Depreciation and amortization (27,627 ) (9,193 ) (3,384 ) (21,612 ) (61,816 ) Net income (loss) $ 2,222 $ 181 $ 639 $ (6,777 ) $ (3,735 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 1,111 $ 91 $ 320 $ (2,909 ) $ (1,387 ) Other-than-temporary impairment - (4,844 ) - - (4,844 ) Basis adjustments and other 155 291 105 293 844 Equity in income (loss) of Real Estate Ventures $ 1,266 $ (4,462 ) $ 425 $ (2,616 ) $ (5,387 ) (a) The Company’s unconsolidated ownership interests ranged from 25% to 70% during the three- and nine-month periods ended September 30, 2018 and 20% to 70% during the three- and nine-month periods ended September 30, 2017, subject to specified priority allocations of distributable cash in certain of the Real Estate Ventures.

Intangible Assets and Liabili_2

Intangible Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets and Liabilities	As of September 30, 2018 and December 31, 2017, the Company’s intangible assets/liabilities were comprised of the following (in thousands): September 30, 2018 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 103,339 $ (51,072 ) $ 52,267 Tenant relationship value 9,597 (8,420 ) 1,177 Above market leases acquired 4,711 (3,016 ) 1,695 Total intangible assets, net $ 117,647 $ (62,508 ) $ 55,139 Acquired lease intangibles, net: Below market leases acquired $ 34,523 $ (16,843 ) $ 17,680 December 31, 2017 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 108,060 $ (47,003 ) $ 61,057 Tenant relationship value 11,201 (9,275 ) 1,926 Above market leases acquired 4,545 (2,556 ) 1,989 Total intangible assets, net $ 123,806 $ (58,834 ) $ 64,972 Acquired lease intangibles, net: Below market leases acquired $ 36,213 $ (15,939 ) $ 20,274
Summary of Amortization for Intangible Assets and Liabilities	As of September 30, 2018, the Company’s annual amortization for its intangible assets/liabilities, assuming no prospective early lease terminations, are as follows (dollars in thousands): Assets Liabilities 2018 (three months remaining) $ 3,645 $ 844 2019 12,735 2,833 2020 10,140 2,069 2021 7,538 1,432 2022 5,355 1,264 Thereafter 15,726 9,238 Total $ 55,139 $ 17,680

Debt Obligations (Tables)

Debt Obligations (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Consolidated debt obligations	The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at September 30, 2018 and December 31, 2017 (in thousands): September 30, 2018 December 31, 2017 Effective Interest Rate Maturity Date MORTGAGE DEBT: Two Logan Square $ 83,220 $ 84,440 3.98% May 2020 Four Tower Bridge 9,583 - 4.50% (a) Feb 2021 One Commerce Square 121,066 123,667 3.64% Apr 2023 Two Commerce Square 111,017 112,000 4.51% Apr 2023 Principal balance outstanding 324,886 320,107 Plus: fair market value premium (discount), net (1,853 ) (2,325 ) Less: deferred financing costs (445 ) (566 ) Mortgage indebtedness $ 322,588 $ 317,216 UNSECURED DEBT Seven-Year Term Loan - Swapped to fixed $ 250,000 $ 250,000 3.72% Oct 2022 $350.0M 3.95% Guaranteed Notes due 2023 350,000 350,000 3.87% Feb 2023 $250.0M 4.10% Guaranteed Notes due 2024 250,000 250,000 4.33% Oct 2024 $450.0M 3.95% Guaranteed Notes due 2027 450,000 450,000 4.03% Nov 2027 $250.0M 4.55% Guaranteed Notes due 2029 250,000 250,000 4.60% Oct 2029 Indenture IA (Preferred Trust I) 27,062 27,062 LIBOR + 1.25% Mar 2035 Indenture IB (Preferred Trust I) - Swapped to fixed 25,774 25,774 3.30% Apr 2035 Indenture II (Preferred Trust II) - Swapped to fixed 25,774 25,774 3.09% Jul 2035 Principal balance outstanding 1,628,610 1,628,610 Plus: original issue premium (discount), net (4,178 ) (4,423 ) Less: deferred financing costs (9,483 ) (10,575 ) Total unsecured indebtedness $ 1,614,949 $ 1,613,612 Total Debt Obligations $ 1,937,537 $ 1,930,828 (a) This loan was assumed upon acquisition of the related property on January 5, 2018. The interest rate reflects the market rate at the time of acquisition.
Schedule of Maturities of Long-term Debt	As of September 30, 2018, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2018 (three months remaining) $ 1,854 2019 7,595 2020 87,226 2021 15,143 2022 256,332 Thereafter 1,585,346 Total principal payments 1,953,496 Net unamortized premiums/(discounts) (6,031 ) Net deferred financing costs (9,928 ) Outstanding indebtedness $ 1,937,537

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of Financial Instruments With Fair Values Different From Their Carrying Amount	The following are financial instruments for which the Company’s estimates of fair value differ from the carrying amounts (in thousands): September 30, 2018 December 31, 2017 Carrying Amount (a) Fair Value Carrying Amount (a) Fair Value Unsecured notes payable $ 1,287,661 $ 1,249,225 $ 1,286,573 $ 1,314,900 Variable rate debt $ 327,288 $ 310,640 $ 327,039 $ 308,872 Mortgage notes payable $ 322,588 $ 314,813 $ 317,216 $ 304,665 Notes receivable (b) $ 47,821 $ 47,858 $ 3,532 $ 3,605 (a) T (b) The inputs to originate the notes receivable are unobservable and, as a result, are categorized as Level 3. The Company determined fair value by calculating the present value of the cash payments to be received through the maturity date of the loans.

Fair Value of Derivative Fina_2

Fair Value of Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value	The following table summarizes the terms and fair values of the Company’s derivative financial instruments as of September 30, 2018 and December 31, 2017. The notional amounts provide an indication of the extent of the Company’s involvement in these instruments at that time, but do not represent exposure to credit, interest rate or market risks (amounts presented in thousands and included in other assets and other liabilities on the Company’s consolidated balance sheets). Hedge Product Hedge Type Designation Notional Amount Strike Trade Date Maturity Date Fair value 9/30/2018 12/31/2017 9/30/2018 12/31/2017 Assets Swap Interest Rate Cash Flow (a) $ 250,000 $ 250,000 3.718 % October 8, 2015 October 8, 2022 $ 12,178 $ 5,694 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 546 25 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 277 59 $ 301,548 $ 301,548 (a) Hedging unsecured variable rate debt.

Beneficiaries Equity of the P_2

Beneficiaries Equity of the Parent Company (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Earnings Per Share (EPS), Basic and Diluted	The following tables detail the number of shares and net income used to calculate basic and diluted earnings per share (in thousands, except share and per share amounts; results may not add due to rounding): Three-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income (loss) $ (43,262 ) $ (43,262 ) $ 19,046 $ 19,046 Net (income) loss attributable to noncontrolling interests 339 339 (170 ) (170 ) Nonforfeitable dividends allocated to unvested restricted shareholders (80 ) (80 ) (73 ) (73 ) Net income (loss) attributable to common shareholders $ (43,003 ) $ (43,003 ) $ 18,803 $ 18,803 Denominator Weighted-average shares outstanding 178,602,622 178,602,622 175,433,657 175,433,657 Contingent securities/Share based compensation - - - 1,401,365 Weighted-average shares outstanding 178,602,622 178,602,622 175,433,657 176,835,022 Earnings (loss) per Common Share: Net income (loss) attributable to common shareholders $ (0.24 ) $ (0.24 ) $ 0.11 $ 0.11 Nine-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 14,579 $ 14,579 $ 48,015 $ 48,015 Net income attributable to noncontrolling interests (167 ) (167 ) (384 ) (384 ) Nonforfeitable dividends allocated to unvested restricted shareholders (280 ) (280 ) (245 ) (245 ) Distribution to preferred shareholders - - (2,032 ) (2,032 ) Preferred share redemption charge - - (3,181 ) (3,181 ) Net income attributable to common shareholders $ 14,132 $ 14,132 $ 42,173 $ 42,173 Denominator Weighted-average shares outstanding 178,515,993 178,515,993 175,315,581 175,315,581 Contingent securities/Share based compensation - 1,236,551 - 1,283,751 Weighted-average shares outstanding 178,515,993 179,752,544 175,315,581 176,599,332 Earnings per Common Share: Net income attributable to common shareholders $ 0.08 $ 0.08 $ 0.24 $ 0.24

Partners Equity of the Operat_2

Partners Equity of the Operating Partnership (Tables)	9 Months Ended
	Sep. 30, 2018
Earnings Per Share (EPS), Basic and Diluted	The following tables detail the number of shares and net income used to calculate basic and diluted earnings per share (in thousands, except share and per share amounts; results may not add due to rounding): Three-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income (loss) $ (43,262 ) $ (43,262 ) $ 19,046 $ 19,046 Net (income) loss attributable to noncontrolling interests 339 339 (170 ) (170 ) Nonforfeitable dividends allocated to unvested restricted shareholders (80 ) (80 ) (73 ) (73 ) Net income (loss) attributable to common shareholders $ (43,003 ) $ (43,003 ) $ 18,803 $ 18,803 Denominator Weighted-average shares outstanding 178,602,622 178,602,622 175,433,657 175,433,657 Contingent securities/Share based compensation - - - 1,401,365 Weighted-average shares outstanding 178,602,622 178,602,622 175,433,657 176,835,022 Earnings (loss) per Common Share: Net income (loss) attributable to common shareholders $ (0.24 ) $ (0.24 ) $ 0.11 $ 0.11 Nine-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 14,579 $ 14,579 $ 48,015 $ 48,015 Net income attributable to noncontrolling interests (167 ) (167 ) (384 ) (384 ) Nonforfeitable dividends allocated to unvested restricted shareholders (280 ) (280 ) (245 ) (245 ) Distribution to preferred shareholders - - (2,032 ) (2,032 ) Preferred share redemption charge - - (3,181 ) (3,181 ) Net income attributable to common shareholders $ 14,132 $ 14,132 $ 42,173 $ 42,173 Denominator Weighted-average shares outstanding 178,515,993 178,515,993 175,315,581 175,315,581 Contingent securities/Share based compensation - 1,236,551 - 1,283,751 Weighted-average shares outstanding 178,515,993 179,752,544 175,315,581 176,599,332 Earnings per Common Share: Net income attributable to common shareholders $ 0.08 $ 0.08 $ 0.24 $ 0.24
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Share (EPS), Basic and Diluted	The following tables detail the number of units and net income used to calculate basic and diluted earnings per common partnership unit (in thousands, except unit and per unit amounts; results may not add due to rounding): Three-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income (loss) $ (43,262 ) $ (43,262 ) $ 19,046 $ 19,046 Net income attributable to noncontrolling interests (20 ) (20 ) (12 ) (12 ) Nonforfeitable dividends allocated to unvested restricted unitholders (80 ) (80 ) (73 ) (73 ) Net income (loss) attributable to common unitholders $ (43,362 ) $ (43,362 ) $ 18,961 $ 18,961 Denominator Weighted-average units outstanding 180,082,421 180,082,421 176,913,456 176,913,456 Contingent securities/Share based compensation - - - 1,401,365 Total weighted-average units outstanding 180,082,421 180,082,421 176,913,456 178,314,821 Earnings (loss) per Common Partnership Unit: Net income (loss) attributable to common unitholders $ (0.24 ) $ (0.24 ) $ 0.11 $ 0.11 Nine-month periods ended September 30, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 14,579 $ 14,579 $ 48,015 $ 48,015 Net income attributable to noncontrolling interests (46 ) (46 ) (25 ) (25 ) Nonforfeitable dividends allocated to unvested restricted unitholders (280 ) (280 ) (245 ) (245 ) Preferred unit dividends - - (2,032 ) (2,032 ) Preferred unit redemption charge - - (3,181 ) (3,181 ) Net income attributable to common unitholders $ 14,253 $ 14,253 $ 42,532 $ 42,532 Denominator Weighted-average units outstanding 179,995,792 179,995,792 176,795,380 176,795,380 Contingent securities/Share based compensation - 1,236,551 - 1,283,751 Total weighted-average units outstanding 179,995,792 181,232,343 176,795,380 178,079,131 Earnings per Common Partnership Unit Net income attributable to common unitholders $ 0.08 $ 0.08 $ 0.24 $ 0.24

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2018
Segment Reporting [Abstract]
Real Estate Investments, Net Operating Income and Unconsolidated Real Estate Ventures of Reportable Segments	The following tables provide selected asset information and results of operations of the Company's reportable segments (in thousands): Real estate investments, at cost: September 30, 2018 December 31, 2017 Philadelphia CBD $ 1,652,819 $ 1,643,296 Pennsylvania Suburbs 979,068 958,796 Metropolitan Washington, D.C. (a) 539,105 978,257 Austin, Texas 170,912 163,653 Other 87,144 88,346 $ 3,429,048 $ 3,832,348 Assets held for sale (a) 396,072 - Operating properties $ 3,825,120 $ 3,832,348 Corporate Construction-in-progress $ 157,075 $ 121,188 Land held for development (b) $ 77,578 $ 98,242 Prepaid leasehold interests in land held for development, net (c) $ 40,100 $ - (a) As of September 30, 2018, eight office properties in the Metropolitan Washington, D.C. segment were classified as held for sale. See Note 3, “Real Estate Investments,” for further information. (b) As of September 30, 2018, the Company categorized 37.9 acres of land held for development, comprised of 2.7 acres and 35.2 acres, located in the Pennsylvania Suburbs segment and Other segment, respectively, as held for sale in accordance with applicable accounting standards for long lived assets. As of December 31, 2017, the Company categorized 13.1 acres of land held for development, located in the Other segment, as held for sale in accordance with applicable accounting standards for long lived assets. (c) As of September 30, 2018, this caption comprised leasehold interests in prepaid 99-year ground leases at 3025 and 3001-3003 JFK Boulevard, in Philadelphia, Pennsylvania. See Note 3, “Real Estate Investments,” Net operati ng income (in thousands): Three-month periods ended September 30, 2018 2017 Total revenue Operating expenses (a) Net operating income (loss) Total revenue Operating expenses (a) Net operating income Philadelphia CBD $ 64,352 $ (24,427 ) $ 39,925 $ 56,452 $ (22,010 ) $ 34,442 Pennsylvania Suburbs 34,745 (11,937 ) 22,808 34,861 (11,846 ) 23,015 Metropolitan Washington, D.C. 22,754 (8,548 ) 14,206 23,079 (8,500 ) 14,579 Austin, Texas 8,641 (3,894 ) 4,747 7,886 (3,929 ) 3,957 Other 3,707 (2,436 ) 1,271 3,752 (2,647 ) 1,105 Corporate 799 (1,636 ) (837 ) 2,408 (1,769 ) 639 Operating properties $ 134,998 $ (52,878 ) $ 82,120 $ 128,438 $ (50,701 ) $ 77,737 Nine-month periods ended September 30, 2018 2017 Total revenue Operating expenses (a) Net operating income (loss) Total revenue Operating expenses (a) Net operating income Philadelphia CBD $ 190,478 $ (73,559 ) $ 116,919 $ 165,352 $ (64,311 ) $ 101,041 Pennsylvania Suburbs 103,960 (37,018 ) 66,942 105,673 (35,670 ) 70,003 Metropolitan Washington, D.C. 69,012 (25,699 ) 43,313 69,190 (26,347 ) 42,843 Austin, Texas 25,474 (10,812 ) 14,662 25,772 (11,634 ) 14,138 Other 13,187 (9,601 ) 3,586 14,274 (9,083 ) 5,191 Corporate 3,031 (5,240 ) (2,209 ) 6,888 (5,355 ) 1,533 Operating properties $ 405,142 $ (161,929 ) $ 243,213 $ 387,149 $ (152,400 ) $ 234,749 (a) Includes property operating expenses, real estate taxes and third party management expense. Unconsolidated real estate ventures (in thousands): Investment in real estate ventures, at equity Equity in income (loss) of real estate venture As of Three-month periods ended September 30, Nine-month periods ended September 30, September 30, 2018 December 31, 2017 2018 2017 2018 2017 Philadelphia CBD $ 20,544 $ 39,939 $ (36 ) $ 134 $ (183 ) $ 113 Pennsylvania Suburbs - 3,503 - 24 - 448 Metropolitan Washington, D.C. 119,032 119,817 (31 ) (5,264 ) (431 ) (4,872 ) Austin, Texas 14,411 13,973 423 (15 ) 1,156 1,266 MAP Venture (a) 11,939 15,450 (444 ) (706 ) (2,011 ) (2,610 ) Other 1,856 1,939 89 104 287 268 Total $ 167,782 $ 194,621 $ 1 $ (5,723 ) $ (1,182 ) $ (5,387 ) (a) The MAP Venture represents a joint venture, formed on February 4, 2016 between the Company and MAP Ground Lease Holdings LLC, an affiliate of Och-Ziff Capital Management Group, LLC. The MAP Venture’s business operations, including properties in Richmond, Virginia; Metropolitan Washington, D.C.; New Jersey/Delaware and Pennsylvania Suburbs, are centrally managed with the results reported to management of the Company on a consolidated basis. As a result, the investment in the MAP Venture is separately presented. All other unconsolidated real estate ventures are managed consistently with the Company’s regional segments.
Reconciliation of Consolidated Net Income to Consolidated NOI	The following is a reconciliation of consolidated net in come, as defined by GAAP, to consolidated NOI, (in thousands): Three-month periods ended September 30, Nine-month periods ended September 30, 2018 2017 2018 2017 Net income (loss) $ (43,262 ) $ 19,046 $ 14,579 $ 48,015 Plus: Interest expense 19,257 19,732 58,091 61,473 Interest expense - amortization of deferred financing costs 618 577 1,872 1,807 Depreciation and amortization 43,900 42,429 130,908 132,584 General and administrative expenses 5,963 5,813 22,209 21,797 Equity in (income) loss of Real Estate Ventures (1 ) 5,723 1,182 5,387 Provision for impairment 56,865 - 56,865 3,057 Less: Interest income 1,220 79 2,564 635 Income tax (provision) benefit - 793 (158 ) 1,032 Net gain (loss) on disposition of real estate - - (35 ) 8,411 Net gain on sale of undepreciated real estate - 953 2,859 953 Net gain on Real Estate Venture transactions - 13,758 37,263 28,340 Consolidated net operating income $ 82,120 $ 77,737 $ 243,213 $ 234,749

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Minimum Future Rental Payments on Non-cancelable Leases	Minimum future rental payments on non-cancelable leases at September 30, 2018 are as follows (in thousands): Year Minimum Rent 2018 (three months remaining) $ 306 2019 1,222 2020 1,222 2021 1,222 2022 1,222 Thereafter 56,911 Total $ 62,105

Organization of The Parent Co_3

Organization of The Parent Company and The Operating Partnership (Textual) (Details)	9 Months Ended
	Sep. 30, 2018ft²apropertyParcel
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties | property	93
Net Rentable Square Feet	16,462,764
Development Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties | property	2
Redevelopment Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties | property	5
Parent Company [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the Operating Partnership	99.20%
Undeveloped Parcels of Land | a	234
Undeveloped Land Held for Sale | a	37.9
Area of Additional Undeveloped Parcels of Land With Option to Purchase | a	55.5
Total Potential Development Capacity	14,200,000
Parent Company [Member] | Land Parcel One [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Lease agreement term	99 years
Parent Company [Member] | Land Parcel Two [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Lease agreement term	99 years
Parent Company [Member] | Assets Held-for-sale [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Total Potential Development Capacity	400,000
Parent Company [Member] | Leashold Interest Land [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Parcels | Parcel	2
Undeveloped Parcels of Land Held | a	1.8
Wholly-owned Management Company Subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet	25,300,000
Wholly-owned Management Company Subsidiaries [Member] | Wholly Owned Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet	16,500,000
Wholly-owned Management Company Subsidiaries [Member] | Partially Owned Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet	8,800,000

Organization of The Parent Co_4

Organization of The Parent Company and The Operating Partnership - Summary of Core Portfolio of Operating Properties and Excludes Development and Redevelopment Properties Under Construction (Details)	Sep. 30, 2018ft²property
Real Estate Properties [Line Items]
Number of Properties | property	93
Rentable Square Feet | ft²	16,462,764
Office Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	73
Rentable Square Feet | ft²	13,673,405
Mixed-use Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	4
Rentable Square Feet | ft²	646,741
Retail Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	1
Rentable Square Feet | ft²	17,884
Core Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	78
Rentable Square Feet | ft²	14,338,030
Development Projects [Member]
Real Estate Properties [Line Items]
Number of Properties | property	2
Rentable Square Feet | ft²	247,818
Redevelopment Projects [Member]
Real Estate Properties [Line Items]
Number of Properties | property	5
Rentable Square Feet | ft²	583,719
Held for Sale Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	8	[1]
Rentable Square Feet | ft²	1,293,197	[1]
[1]	As of September 30, 2018, eight office properties were classified as held for sale in the Company’s Metropolitan Washington, D.C. segment. See Note 3, “ Real Estate Investments

Organization of The Parent Co_5

Organization of The Parent Company and The Operating Partnership - Summary of Core Portfolio of Operating Properties and Excludes Development and Redevelopment Properties Under Construction (Parenthetical) (Details)	Sep. 30, 2018property
Real Estate Properties [Line Items]
Number of Properties	93
Office Properties [Member] | Assets Held-for-sale [Member]
Real Estate Properties [Line Items]
Number of Properties	8

Basis of Presentation (Textual)

Basis of Presentation (Textual) (Details)

Aug. 23, 2018

Mar. 15, 2017USD ($)ft²

Jul. 01, 2016USD ($)a

Dec. 03, 2015ft²

Sep. 30, 2018USD ($)aParcel

Sep. 30, 2017USD ($)

Dec. 31, 2016USD ($)

Sep. 30, 2018USD ($)aParcel

Sep. 30, 2017USD ($)

Dec. 31, 2019USD ($)

Jun. 30, 2018USD ($)

Mar. 16, 2018a

Dec. 31, 2017USD ($)

Apr. 28, 2017a

Jan. 30, 2017a

Basis Of Presentation [Line Items]

Income tax provision

$ 0

$ (793,000)

$ 158,000

$ (1,032,000)

Increase in operating cash flows

9,831,000

8,361,000

Lease agreement variable income

0

Third party management contracts assets outstanding

0

0

Third party management contracts liabilities outstanding

0

0

Proceeds from the sale of properties

16,771,000

114,821,000

Assets held for sale, net

297,194,000

297,194,000

$ 392,000

Gain (Loss) on Sale

0

0

$ (35,000)

8,411,000

Scenario Plan [Member]

Basis Of Presentation [Line Items]

Increase in operating expenses

$ 3,600,000

Scenario Plan [Member] | Land Lease Arrangements

Basis Of Presentation [Line Items]

Increase in operating expenses

$ 800,000

Subaru Build-to-Service Center Project [Member]

Basis Of Presentation [Line Items]

Rentable Square Feet | ft²

83,000

Lease terms

18 years

Purchase option of lease from inception period

5 years

5 years

Sales-type lease, interest income

$ 400,000

Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of developed parcels of land (in acres) | a

34.6

Gross purchase value of assets

$ 20,600,000

Number of Parcels | Parcel

3

3

Parcel One [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of land sold | a

8.4

Parcel Two [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of land sold | a

1.7

Parcel Three [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of land sold | a

6.6

Garza Land Sale [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of developed parcels of land (in acres) | a

34.6

Gross purchase value of assets

$ 20,600,000

Number of Parcels | Parcel

3

3

Aggregate deferred gain recognized

$ 0

$ 0

$ 2,800,000

Garza Land Sale [Member] | Parcel One [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of land sold | a

8.4

8.4

Garza Land Sale [Member] | Parcel One [Member] | Garza Land Acquisition [Member] | Third Party Developers [Member]

Basis Of Presentation [Line Items]

Date of parcels sold

Jan. 30, 2017

Garza Land Sale [Member] | Parcel Two [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of land sold | a

1.7

1.7

Garza Land Sale [Member] | Parcel Two [Member] | Garza Land Acquisition [Member] | Third Party Developers [Member]

Basis Of Presentation [Line Items]

Date of parcels sold

Apr. 28, 2017

Garza Land Sale [Member] | Parcel Three [Member] | Garza Land Acquisition [Member]

Basis Of Presentation [Line Items]

Area of land sold | a

6.6

6.6

Garza Land Sale [Member] | Parcel Three [Member] | Garza Land Acquisition [Member] | Third Party [Member]

Basis Of Presentation [Line Items]

Date of parcels sold

Mar. 16, 2018

Philadelphia Marine Center (Marine Piers) [Member]

Basis Of Presentation [Line Items]

Aggregate deferred gain recognized

$ 9,400,000

Rentable Square Feet | ft²

181,900

Sales Price

$ 21,400,000

Payment by cash on purchases

12,000,000

Proceeds from the sale of properties

11,200,000

Balance payment on purchases

$ 9,400,000

Date of second installment payment

Jan. 31, 2020

Assets held for sale, net

$ 4,700,000

Gain (Loss) on Sale

$ 6,500,000

ASU 2016-18 [Member]

Basis Of Presentation [Line Items]

Restricted cash

$ 800,000

1,300,000

$ 800,000

1,300,000

Increase in operating cash flows

600,000

General and Administrative Expenses [Member]

Basis Of Presentation [Line Items]

Income tax provision

800,000

1,000,000

Net Income Tax Provision [Member]

Basis Of Presentation [Line Items]

Reclassification of net income tax provision out of general and administrative expenses into net income tax provision

$ 800,000

$ 1,000,000

Impairment Charges [Member]

Basis Of Presentation [Line Items]

Out-of-period error immaterial in current year

$ 1,200,000

Basis of Presentation - Summary

Basis of Presentation - Summary of Revenue Earned by Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		$ 134,998		$ 128,438	$ 405,142		$ 387,149
Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		64,352			190,478
Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		34,745			103,960
Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		22,754			69,012
Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		8,641			25,474
Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		3,707			13,187
Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Total revenue		799	[1]	2,408	3,031	[1]	6,888
Base Rent [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		98,591			291,762
Base Rent [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		42,289			121,940
Base Rent [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		29,116			88,929
Base Rent [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		20,635			61,575
Base Rent [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		5,008			14,442
Base Rent [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		2,035			6,340
Base Rent [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue	[1]	(492)			(1,464)
Straight Line Rent [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		2,534			10,765
Straight Line Rent [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		1,912			9,194
Straight Line Rent [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		1,202			2,208
Straight Line Rent [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		(492)			(645)
Straight Line Rent [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		(43)			164
Straight Line Rent [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		65			189
Straight Line Rent [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue	[1]	(110)			(345)
Point of Sale [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		6,455			19,070
Point of Sale [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		5,905			17,526
Point of Sale [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		73			201
Point of Sale [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		287			783
Point of Sale [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		134			385
Point of Sale [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		56			175
Point of Sale [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue	[1]	0			0
Rents [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		107,580		102,557	321,597		307,446
Rents [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		50,106			148,660
Rents [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		30,391			91,338
Rents [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		20,430			61,713
Rents [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		5,099			14,991
Rents [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		2,156			6,704
Rents [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue	[1]	(602)			(1,809)
Tenant Reimbursements [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		20,557		17,239	59,094		53,812
Tenant Reimbursements [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		13,087			37,585
Tenant Reimbursements [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		3,704			10,795
Tenant Reimbursements [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		902			2,687
Tenant Reimbursements [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		2,286			6,258
Tenant Reimbursements [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		698			2,124
Tenant Reimbursements [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue	[1]	(120)			(355)
Termination Fees [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		498		$ 200	1,630		$ 2,013
Termination Fees [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		37			192
Termination Fees [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		461			1,300
Termination Fees [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		0			138
Termination Fees [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		0			0
Termination Fees [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue		0			0
Termination Fees [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Lease revenue	[1]	0			0
Third Party Management Fees, Labor Reimbursement and Leasing [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		4,944			17,531
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		203			632
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		6			18
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		1,279			4,130
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		1,223			4,155
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		846			4,345
Third Party Management Fees, Labor Reimbursement and Leasing [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue	[1]	1,387			4,251
Other Income [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		1,419			5,290
Other Income [Member] | Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		919			3,409
Other Income [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		183			509
Other Income [Member] | Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		143			344
Other Income [Member] | Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		33			70
Other Income [Member] | Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue		7			14
Other Income [Member] | Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Service and other revenue	[1]	$ 134			$ 944
[1]	Corporate includes intercompany eliminations necessary to reconcile to consolidated Company totals.

Basis of Presentation - Summa_2

Basis of Presentation - Summary of Gain on Sale for Each Land Parcel (Details) $ in Thousands	Mar. 16, 2018USD ($)aParcel		Apr. 28, 2017USD ($)aParcel	Jan. 30, 2017USD ($)aParcel	Sep. 30, 2018USD ($)aParcel	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)aParcel	Sep. 30, 2017USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties							$ 16,771	$ 114,821
Gain on Sale					$ 0	$ 953	$ 2,859	$ 953
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel					2		2
Acreage of land | a					19.7		19.7
Sales Price					$ 15,056		$ 15,056
Proceeds from the sale of properties							14,921
Gain on Sale							1,446
Garza Ranch - Office [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel	1
Acreage of land | a	6.6
Sales Price	$ 14,571
Proceeds from the sale of properties	14,509
Gain on Sale	$ 1,424	[1]					1,424
Garza Ranch - Multifamily [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel			1
Acreage of land | a			8.4
Sales Price			$ 11,800
Proceeds from the sale of properties			$ 11,560
Gain on Sale							1,233
Garza Ranch - Hotel [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				1
Acreage of land | a				1.7
Sales Price				$ 3,500
Proceeds from the sale of properties				$ 3,277
Gain on Sale							$ 180
Garza Ranch [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel					3		3
Acreage of land | a					16.7		16.7
Sales Price					$ 29,871		$ 29,871
Proceeds from the sale of properties							29,346
Gain on Sale							$ 2,837
[1]	As of March 31, 2018, the Company had not transferred control to the buyer of this land parcel, or two other parcels at this site which were sold during 2017, because of a completion guarantee which required the Company, as developer, to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three months ended June 30, 2018, the infrastructure improvements were substantially completed, at which time the Company transferred control of the land parcels. As a result, the Company then recognized the sale. See Note 2, “Basis of Presentation,” for further discussion of the infrastructure improvements and related revenue recognition

Real Estate Investments - Gross

Real Estate Investments - Gross Carrying Value of Operating Properties (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment, Gross [Abstract]
Land		$ 437,640	$ 492,197
Tenant improvements		411,668	444,038
Operating properties		3,429,048	3,832,348
Assets held for sale - real estate investments	[1]	396,072	0
Total		3,825,120	3,832,348
Building and Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Operating properties		$ 2,579,740	$ 2,896,113
[1]	As of September 30, 2018, eight office properties in the Metropolitan Washington, D.C. segment were classified as held for sale. See Note 3, “Real Estate Investments,” for further information.

Real Estate Investments - Acqui

Real Estate Investments - Acquisitions (Textual) (Details) $ in Thousands		Jun. 29, 2018USD ($)ft²a	Mar. 22, 2018USD ($)a	Jan. 05, 2018USD ($)ft²	Sep. 30, 2018USD ($)ft²	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)ft²	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Business Acquisition [Line Items]
Prepaid leasehold interests in land held for development, net	[1]				$ 40,100		$ 40,100		$ 0
Capitalized transaction costs							$ 10,664	$ 12,553
Area of real estate property | ft²					16,462,764		16,462,764
Net income (loss)					$ (42,923)	$ 18,876	$ 14,412	$ 47,631
Seven Tower Bridge [Member]
Business Acquisition [Line Items]
Sale of ownership interest percentage				20.00%
3025 JFK Boulevard [Member]
Business Acquisition [Line Items]
Lease agreement term		99 years
Area of developed parcels of land (in acres) | a		1
Prepaid leasehold interests in land held for development, net		$ 15,000
Capitalized transaction costs		300
3025 JFK Boulevard [Member] | Other Assets [Member]
Business Acquisition [Line Items]
Leasehold valuation credit		5,600
3001-3003 and 3025 JFK Boulevard [Member]
Business Acquisition [Line Items]
Lease agreement term							99 years
Leasehold valuation credit applied to development		$ 2,400
Minimum floor area ratio required for realization of credit | ft²		1,200,000
Remaining leasehold valuation credit		$ 3,200
Reimbursable leasehold valuation credit		$ 3,200
3001-3003 JFK Boulevard [Member]
Business Acquisition [Line Items]
Lease agreement term			99 years
Area of developed parcels of land (in acres) | a			1
Prepaid leasehold interests in land held for development, net			$ 24,600
Capitalized transaction costs			$ 300
Four Tower Bridge [Member]
Business Acquisition [Line Items]
Ownership percentage				35.00%
Percentage of ownership interest after non-monetary exchange transaction				100.00%
Capitalized transaction costs				$ 100
Fair value of unencumbered acquisition related costs, to tangible and intangible assets and liabilities				$ 23,600
Service and other revenue					700		$ 2,100
Net income (loss)					$ 100		$ (100)
Four Tower Bridge [Member] | Conshohocken [Member] | Pennsylvania [Member]
Business Acquisition [Line Items]
Area of real estate property | ft²				86,021
Real estate property debt				$ 9,700
[1]	As of September 30, 2018, this caption comprised leasehold interests in prepaid 99-year ground leases at 3025 and 3001-3003 JFK Boulevard, in Philadelphia, Pennsylvania. See Note 3, “Real Estate Investments,”

Real Estate Investments - Purch

Real Estate Investments - Purchase Price Allocation (Details) - Four Tower Bridge [Member] $ in Thousands	Jan. 05, 2018USD ($)
Business Acquisition [Line Items]
Building, land and improvements	$ 20,734
Intangible assets acquired	3,144	[1]
Below market lease liabilities assumed	(182)	[2]
Total unencumbered acquisition value	23,696
Mortgage debt assumed - at fair value	(9,940)	[3]
Total encumbered acquisition value	13,756
Total unencumbered acquisition value	23,696
Mortgage debt assumed - at fair value	(9,940)	[3]
Investment in unconsolidated real estate ventures	(3,502)
Net working capital assumed	1,379
Gain on real estate venture transactions	$ 11,633
[1]	Weighted average amortization period of 4.1 years.
[2]	Weighted average amortization period of 4.8 years.
[3]	The outstanding principal balance on mortgage debt assumed at January 5, 2018 was $9.7 million.

Real Estate Investments - Pur_2

Real Estate Investments - Purchase Price Allocation (Parenthetical) (Details) - USD ($) $ in Thousands	Jan. 05, 2018	Sep. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Outstanding principal balance on mortgage debt assumed		$ 322,588	$ 317,216
Four Tower Bridge [Member] | Intangible Assets Acquired [Member]
Business Acquisition [Line Items]
Weighted average amortization period	4 years 1 month 6 days
Four Tower Bridge [Member] | Below Market Lease [Member]
Business Acquisition [Line Items]
Weighted average amortization period	4 years 9 months 18 days
Four Tower Bridge [Member] | Mortgage Debt Assumed - at Fair Value [Member]
Business Acquisition [Line Items]
Outstanding principal balance on mortgage debt assumed	$ 9,700

Real Estate Investments - Summa

Real Estate Investments - Summary of Office Property Sold (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)ft²	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)ft²property	Sep. 30, 2017USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties			$ 16,771	$ 114,821
Gain (Loss) on Sale	$ 0	$ 0	$ (35)	$ 8,411
Office Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property			1
Rentable Square Feet | ft²	38,260		38,260
Sales Price	$ 2,000		$ 2,000
Proceeds from the sale of properties			1,850
Gain (Loss) on Sale			$ (35)
20 East Clementon Road [Member] | Office Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property			1
Rentable Square Feet | ft²	38,260		38,260
Sales Price	$ 2,000		$ 2,000
Proceeds from the sale of properties			1,850
Gain (Loss) on Sale			$ (35)

Real Estate Investments - Sum_2

Real Estate Investments - Summary of Land Parcels Sold (Details) $ in Thousands	Mar. 16, 2018USD ($)aParcel		Jan. 10, 2018USD ($)aParcel	Sep. 30, 2018USD ($)aParcel	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)aParcel	Sep. 30, 2017USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties						$ 16,771	$ 114,821
Gain on Sale				$ 0	$ 953	$ 2,859	$ 953
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				2		2
Acreage of land | a				19.7		19.7
Sales Price				$ 15,056		$ 15,056
Proceeds from the sale of properties						14,921
Gain on Sale						1,446
Garza Ranch - Office [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel	1
Acreage of land | a	6.6
Sales Price	$ 14,571
Proceeds from the sale of properties	14,509
Gain on Sale	$ 1,424	[1]				$ 1,424
Westpark Land [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel			1
Acreage of land | a			13.1
Sales Price			$ 485
Proceeds from the sale of properties			412
Gain on Sale			$ 22
[1]	As of March 31, 2018, the Company had not transferred control to the buyer of this land parcel, or two other parcels at this site which were sold during 2017, because of a completion guarantee which required the Company, as developer, to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets. During the three months ended June 30, 2018, the infrastructure improvements were substantially completed, at which time the Company transferred control of the land parcels. As a result, the Company then recognized the sale. See Note 2, “Basis of Presentation,” for further discussion of the infrastructure improvements and related revenue recognition

Real Estate Investments - Sum_3

Real Estate Investments - Summary of Land Parcels Sold (Parenthetical) (Details)	Dec. 31, 2017Parcel
Garza Ranch - Office [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels	2

Real Estate Investments - Sum_4

Real Estate Investments - Summary of Properties Classified as Held for Sale Included in Continuing Operations (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
ASSETS HELD FOR SALE
Total assets held for sale, net		$ 297,194	$ 392
LIABILITIES HELD FOR SALE
Total liabilities held for sale		826	$ 0
Held for Sale Properties Included in Continuing Operations [Member]
ASSETS HELD FOR SALE
Operating properties		396,072
Accumulated depreciation		(112,600)
Operating real estate investments, net		283,472
Construction-in-progress		1,748
Land inventory		11,575
Total real estate investments		296,795
Other assets		399
Total assets held for sale, net		297,194
LIABILITIES HELD FOR SALE
Other liabilities		826
Total liabilities held for sale		826
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member]
ASSETS HELD FOR SALE
Operating properties	[1]	396,072
Accumulated depreciation	[1]	(112,600)
Operating real estate investments, net	[1]	283,472
Construction-in-progress	[1]	1,748
Land inventory	[1]	0
Total real estate investments	[1]	285,220
Other assets	[1]	399
Total assets held for sale, net	[1]	285,619
LIABILITIES HELD FOR SALE
Other liabilities	[1]	826
Total liabilities held for sale	[1]	826
Held for Sale Properties Included in Continuing Operations [Member] | Pennsylvania Suburbs - Land [Member]
ASSETS HELD FOR SALE
Operating properties	[2]	0
Accumulated depreciation	[2]	0
Operating real estate investments, net	[2]	0
Construction-in-progress	[2]	0
Land inventory	[2]	4,254
Total real estate investments	[2]	4,254
Other assets	[2]	0
Total assets held for sale, net	[2]	4,254
LIABILITIES HELD FOR SALE
Other liabilities	[2]	0
Total liabilities held for sale	[2]	0
Held for Sale Properties Included in Continuing Operations [Member] | Other - Land [Member]
ASSETS HELD FOR SALE
Operating properties	[2]	0
Accumulated depreciation	[2]	0
Operating real estate investments, net	[2]	0
Construction-in-progress	[2]	0
Land inventory	[2]	7,321
Total real estate investments	[2]	7,321
Other assets	[2]	0
Total assets held for sale, net	[2]	7,321
LIABILITIES HELD FOR SALE
Other liabilities	[2]	0
Total liabilities held for sale	[2]	$ 0
[1]	As of September 30, 2018, the Company determined that the sale of eight office properties, containing 1,293,197 rentable square feet, in the Metropolitan Washington, D.C. segment, was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the $366.0 million carrying value of the properties exceeded the estimated $309.1 million fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $56.9 million during the three-month period ended September 30, 2018. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of ten years and residual capitalization rates and discount rates of 7.47% and 8.60%, respectively. The results were comparable to indicative pricing in the market. As significant inputs to the model are unobservable, the Company determined that the value determined for this property falls within Level 3 fair value reporting.
[2]	As of September 30, 2018, the Company determined that the sale of one land parcel in the Pennsylvania Suburbs segment and two parcels of land in the Other segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the fair value less the anticipated costs of sale of the properties exceeded the carrying values. As a result, the Company expects to record gains on sale. The fair value measurement will be based on the pricing in the purchase and sale agreements.

Real Estate Investments - Sum_5

Real Estate Investments - Summary of Properties Classified as Held for Sale Included in Continuing Operations (Parenthetical) (Details) $ in Thousands		3 Months Ended	9 Months Ended
		Sep. 30, 2018USD ($)ft²Parcel	Sep. 30, 2018USD ($)ft²propertyParcel	Dec. 31, 2017USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, carrying value		$ 297,194	$ 297,194	$ 392
Held for Sale Properties Included in Continuing Operations [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, carrying value		$ 297,194	$ 297,194
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property			8
Rentable Square Feet | ft²		1,293,197	1,293,197
Assets held for sale, carrying value	[1]	$ 285,619	$ 285,619
Provision for impairment on assets held for sale		56,900
Impairment Hold Period			10 years
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member] | Office Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, carrying value		366,000	$ 366,000
Assets held for sale, fair value		$ 309,100	$ 309,100
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member] | Residual Capitalization Rates [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Measurement input for impairment on assets held for sale		0.0747	0.0747
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member] | Discount Rates [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Measurement input for impairment on assets held for sale		0.0860	0.0860
Held for Sale Properties Included in Continuing Operations [Member] | Pennsylvania Suburbs - Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, carrying value	[2]	$ 4,254	$ 4,254
Number of Parcels | Parcel		1	1
Held for Sale Properties Included in Continuing Operations [Member] | Other - Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Assets held for sale, carrying value	[2]	$ 7,321	$ 7,321
Number of Parcels | Parcel		2	2
[1]	As of September 30, 2018, the Company determined that the sale of eight office properties, containing 1,293,197 rentable square feet, in the Metropolitan Washington, D.C. segment, was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the $366.0 million carrying value of the properties exceeded the estimated $309.1 million fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $56.9 million during the three-month period ended September 30, 2018. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of ten years and residual capitalization rates and discount rates of 7.47% and 8.60%, respectively. The results were comparable to indicative pricing in the market. As significant inputs to the model are unobservable, the Company determined that the value determined for this property falls within Level 3 fair value reporting.
[2]	As of September 30, 2018, the Company determined that the sale of one land parcel in the Pennsylvania Suburbs segment and two parcels of land in the Other segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long-lived assets. At such date, the fair value less the anticipated costs of sale of the properties exceeded the carrying values. As a result, the Company expects to record gains on sale. The fair value measurement will be based on the pricing in the purchase and sale agreements.

Investment in Unconsolidated _3

Investment in Unconsolidated Real Estate Ventures (Textual) (Details)	Aug. 01, 2018USD ($)	Jun. 26, 2018USD ($)	Jan. 10, 2018USD ($)property	Jan. 05, 2018USD ($)ft²	Sep. 30, 2018USD ($)ft²aReal_Estate_InvestmentApartment_unit	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)ft²aReal_Estate_InvestmentApartment_unit	Sep. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method					$ 167,782,000		$ 167,782,000		$ 194,621,000
Accounts receivable					13,871,000		13,871,000		17,938,000
Debt, net					$ 660,041,000		$ 660,041,000		766,420,000
Area of real estate property | ft²					16,462,764		16,462,764
Net gain on Real Estate Venture transactions					$ 0	$ 13,758,000	$ 37,263,000	$ 28,340,000
Proceeds from real estate venture sales							42,953,000	59,022,000
Evo at Cira Disposition [Member]
Schedule Of Equity Method Investments [Line Items]
Sale of ownership interest percentage			50.00%
Net gain on Real Estate Venture transactions			$ 25,700,000
Number of property units sold | property			345
Sales Price			$ 197,500,000
Proceeds from real estate venture sales			43,000,000
Cost of equity method investment			17,300,000
Philadelphia [Member] | Pennsylvania [Member] | Evo at Cira Disposition [Member]
Schedule Of Equity Method Investments [Line Items]
Principal balance of secured loan			$ 110,900,000
Secured Debt [Member]
Schedule Of Equity Method Investments [Line Items]
Real estate property debt					324,886,000		324,886,000		320,107,000
Third Party Management Fees, Labor Reimbursement and Leasing [Member]
Schedule Of Equity Method Investments [Line Items]
Management fees					$ 4,944,000	6,918,000	$ 17,531,000	20,483,000
Office Properties [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²					38,260		38,260
Area of real estate property | ft²					13,673,405		13,673,405
Sales Price					$ 2,000,000		$ 2,000,000
Real Estate Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Accounts receivable					1,200,000		1,200,000		$ 900,000
Real Estate Venture [Member] | Third Party Management Fees, Labor Reimbursement and Leasing [Member]
Schedule Of Equity Method Investments [Line Items]
Management fees					1,400,000	1,700,000	4,000,000	4,900,000
Real Estate Venture [Member] | Lease Commission Income [Member] | Third Party Management Fees, Labor Reimbursement and Leasing [Member]
Schedule Of Equity Method Investments [Line Items]
Management fees					$ 1,500,000	$ 1,900,000	$ 4,400,000	$ 5,500,000
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Investment					10		10
Investment in Real Estate Ventures, equity method					$ 167,800,000		$ 167,800,000
Real estate ventures aggregate indebtedness to third parties					$ 664,200,000		$ 664,200,000
Unconsolidated Real Estate Ventures [Member] | Minimum [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage					25.00%	20.00%	25.00%	20.00%
Unconsolidated Real Estate Ventures [Member] | Maximum [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage					70.00%	70.00%	70.00%	70.00%
Unconsolidated Real Estate Ventures [Member] | Six Real Estate Ventures [Member] | Office Properties [Member]
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Investment					6		6
Rentable Square Feet | ft²					6,600,000		6,600,000
Unconsolidated Real Estate Ventures [Member] | Two Real Estate Ventures [Member] | Land Held For Development [Member]
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Investment					2		2
Acreage of land | a					1.4		1.4
Unconsolidated Real Estate Ventures [Member] | One Real Estate Venture [Member] | Land Under Active Development [Member]
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Investment					1		1
Acreage of land | a					1.3		1.3
Unconsolidated Real Estate Ventures [Member] | One Other Real Estate Venture [Member] | Residential Tower [Member]
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Investment					1		1
Number of Property units | Apartment_unit					321		321
MAP Ground Lease Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage	50.00%
Real estate ventures aggregate indebtedness to third parties	$ 180,800,000
Debt instrument maturity date	Feb. 9, 2019
MAP Ground Lease Venture LLC [Member] | Secured Debt [Member]
Schedule Of Equity Method Investments [Line Items]
Debt instrument maturity date	Aug. 1, 2023
Indebtedness to third parties, refinanced amount	$ 185,000,000
Debt instrument, basis spread on variable rate	2.45%
MAP Ground Lease Venture LLC [Member] | Maximum [Member] | Secured Debt [Member]
Schedule Of Equity Method Investments [Line Items]
Effective interest rate	6.00%
1919 Ventures
Schedule Of Equity Method Investments [Line Items]
Ownership percentage		50.00%
Debt, net		$ 44,400,000
Loan interest rate		4.00%
Mortgage loans scheduled maturity date		Jun. 25, 2023
Repayment of construction loan		$ 88,800,000
Construction loan, principal amount		88,600,000
Accrued interest on construction loan		$ 200,000
1919 Ventures | LCOR/Calstrs [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage		50.00%
1919 Ventures | Other Assets [Member]
Schedule Of Equity Method Investments [Line Items]
Note receivable		$ 44,400,000
Four Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage				35.00%
Net gain on Real Estate Venture transactions				$ 11,600,000
Four Tower Bridge [Member] | Conshohocken [Member] | Pennsylvania [Member]
Schedule Of Equity Method Investments [Line Items]
Area of real estate property | ft²				86,021
Real estate property debt				$ 9,700,000
Seven Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Sale of ownership interest percentage				20.00%
PJP VII [Member]
Schedule Of Equity Method Investments [Line Items]
Real estate property debt					$ 4,200,000		$ 4,200,000
Guarantees, maximum exposure amount					400,000		400,000
4040 Wilson Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Guarantees, maximum exposure amount					41,300,000		41,300,000
Construction loan total borrowing capacity					$ 150,000,000		$ 150,000,000

Investment in Unconsolidated _4

Investment in Unconsolidated Real Estate Ventures - Summary of Financial Position of Real Estate Ventures (Details) - USD ($) $ in Thousands		Sep. 30, 2018		Dec. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Net property		$ 920,900		$ 1,083,965
Other assets		146,366		161,932
Other liabilities		91,094		97,707
Debt, net		660,041		766,420
Equity	[1]	316,131		381,770
DRA Austin Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		258,424		263,557
Other assets		39,398		42,272
Other liabilities		18,705		24,131
Debt, net		246,158		248,700
Equity	[1]	32,959		32,998
BDN - Al Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		157,824		158,960
Other assets		23,133		24,181
Other liabilities		4,347		4,493
Debt, net		92,642		92,917
Equity	[1]	83,968		85,731
HSRE-BDN I, LLC (evo at Cira Centre South) [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		0	[2]	143,990
Other assets		0	[2]	8,563
Other liabilities		0	[2]	1,648
Debt, net		0	[2]	110,136
Equity	[1]	0	[2]	40,769
Other Income [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		504,652		517,458
Other assets		83,835		86,916
Other liabilities		68,042		67,435
Debt, net		321,241		314,667
Equity	[1]	$ 199,204		$ 222,272
[1]	This amount includes the effect of the basis difference between the Company's historical cost basis and the basis recorded at the Real Estate Venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials occur from the impairment of investments, purchases of third party interests in existing Real Estate Ventures and upon the transfer of assets that were previously owned by the Company into a Real Estate Venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the Real Estate Venture level.
[2]	On January 10, 2018, HSRE-BDN I, LLC (evo at Cira Centre South) sold the 345-unit student housing tower, its sole operating asset. See ‘evo at Cira Disposition’ section below

Investment in Unconsolidated _5

Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule Of Equity Method Investments [Line Items]
Equity in income (loss) of Real Estate Ventures	$ 1	$ (5,723)	$ (1,182)	$ (5,387)
DRA Austin Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	14,232	22,493	42,492	70,185
Operating expenses	(6,428)	(10,107)	(18,245)	(29,119)
Interest expense, net	(2,549)	(3,784)	(7,070)	(11,217)
Depreciation and amortization	(4,896)	(9,334)	(15,622)	(27,627)
Loss on early extinguishment of debt	0		0
Net income (loss)	$ 359	$ (732)	$ 1,555	$ 2,222
Ownership interest %	50.00%	50.00%	50.00%	50.00%
Company's share of net income (loss)	$ 180	$ (366)	$ 778	$ 1,111
Other-than-temporary impairment		0		0
Basis adjustments and other	243	351	378	155
Equity in income (loss) of Real Estate Ventures	423	(15)	1,156	1,266
Brandywine - AI Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	5,962	8,438	17,768	23,751
Operating expenses	(2,589)	(4,359)	(8,010)	(10,547)
Interest expense, net	(873)	(1,384)	(2,606)	(3,830)
Depreciation and amortization	(2,232)	(3,251)	(6,915)	(9,193)
Loss on early extinguishment of debt	0		0
Net income (loss)	$ 268	$ (556)	$ 237	$ 181
Ownership interest %	50.00%	50.00%	50.00%	50.00%
Company's share of net income (loss)	$ 134	$ (278)	$ 119	$ 91
Other-than-temporary impairment		(4,844)		(4,844)
Basis adjustments and other	31	(8)	33	291
Equity in income (loss) of Real Estate Ventures	165	(5,130)	152	(4,462)
HSRE-BDN I, LLC (evo at Cira Centre South) [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	0	3,009	995	9,264
Operating expenses	0	(841)	(250)	(2,232)
Interest expense, net	0	(1,097)	(388)	(3,009)
Depreciation and amortization	0	(1,128)	(376)	(3,384)
Loss on early extinguishment of debt	0		(718)
Net income (loss)	$ 0	$ (57)	$ (737)	$ 639
Ownership interest %	50.00%	50.00%	50.00%	50.00%
Company's share of net income (loss)	$ 0	$ (29)	$ (369)	$ 320
Other-than-temporary impairment		0		0
Basis adjustments and other	0	53	11	105
Equity in income (loss) of Real Estate Ventures	0	24	(358)	425
Other Income [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	21,823	22,571	64,684	66,409
Operating expenses	(12,123)	(12,111)	(35,492)	(35,858)
Interest expense, net	(4,122)	(5,406)	(13,558)	(15,716)
Depreciation and amortization	(6,135)	(6,970)	(18,526)	(21,612)
Loss on early extinguishment of debt	(334)		(334)
Net income (loss)	(891)	(1,916)	(3,226)	(6,777)
Company's share of net income (loss)	(550)	(1,002)	(1,946)	(2,909)
Other-than-temporary impairment		0		0
Basis adjustments and other	(37)	400	(186)	293
Equity in income (loss) of Real Estate Ventures	(587)	(602)	(2,132)	(2,616)
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	42,017	56,511	125,939	169,609
Operating expenses	(21,140)	(27,418)	(61,997)	(77,756)
Interest expense, net	(7,544)	(11,671)	(23,622)	(33,772)
Depreciation and amortization	(13,263)	(20,683)	(41,439)	(61,816)
Loss on early extinguishment of debt	(334)		(1,052)
Net income (loss)	(264)	(3,261)	(2,171)	(3,735)
Company's share of net income (loss)	(236)	(1,675)	(1,418)	(1,387)
Other-than-temporary impairment		(4,844)		(4,844)
Basis adjustments and other	237	796	236	844
Equity in income (loss) of Real Estate Ventures	$ 1	$ (5,723)	$ (1,182)	$ (5,387)

Investment in Unconsolidated _6

Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Parenthetical) (Details) - Unconsolidated Real Estate Ventures [Member]	Sep. 30, 2018	Sep. 30, 2017
Minimum [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage	25.00%	20.00%
Maximum [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage	70.00%	70.00%

Intangible Assets and Liabili_3

Intangible Assets and Liabilities - Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Intangible Assets, Total Cost	$ 117,647	$ 123,806
Intangible Assets, Accumulated Amortization	(62,508)	(58,834)
Intangible Assets, net	55,139	64,972
Acquired Lease Intangibles, Net	17,680	20,274
Below market leases [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross	34,523	36,213
Acquired Lease Intangibles, Accumulated Amortization	(16,843)	(15,939)
Acquired Lease Intangibles, Net	17,680	20,274
In-place lease value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	103,339	108,060
Intangible Assets, Accumulated Amortization	(51,072)	(47,003)
Intangible Assets, net	52,267	61,057
Tenant relationship value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	9,597	11,201
Intangible Assets, Accumulated Amortization	(8,420)	(9,275)
Intangible Assets, net	1,177	1,926
Above market leases acquired [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	4,711	4,545
Intangible Assets, Accumulated Amortization	(3,016)	(2,556)
Intangible Assets, net	$ 1,695	$ 1,989

Intangible Assets and Liabili_4

Intangible Assets and Liabilities - Annual Amortization of Intangible Assets, Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
2018 (three months remaining)	$ 3,645
2,019	12,735
2,020	10,140
2,021	7,538
2,022	5,355
Thereafter	15,726
Intangible Assets, net	55,139	$ 64,972
Liabilities
2018 (three months remaining)	844
2,019	2,833
2,020	2,069
2,021	1,432
2,022	1,264
Thereafter	9,238
Acquired Lease Intangibles, Net	$ 17,680	$ 20,274

Debt Obligations - Consolidated

Debt Obligations - Consolidated Debt Obligations Outstanding (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
Consolidated debt obligations
Plus: premiums/(discounts), net		$ (6,031)
Less: deferred financing costs		(9,928)
Total Debt Obligations		1,937,537	$ 1,930,828
Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		324,886	320,107
Plus: premiums/(discounts), net		(1,853)	(2,325)
Less: deferred financing costs		(445)	(566)
Total mortgage indebtedness		322,588	317,216
Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		1,628,610	1,628,610
Plus: premiums/(discounts), net		(4,178)	(4,423)
Less: deferred financing costs		(9,483)	(10,575)
Total unsecured indebtedness		1,614,949	1,613,612
Two Logan Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 83,220	84,440
Effective interest rate		3.98%
Debt instrument maturity date		May 1, 2020
Four Tower Bridge [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 9,583
Effective interest rate	[1]	4.50%
Debt instrument maturity date		Feb. 28, 2021
One Commerce Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 121,066	123,667
Effective interest rate		3.64%
Debt instrument maturity date		Apr. 5, 2023
Two Commerce Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 111,017	112,000
Effective interest rate		4.51%
Debt instrument maturity date		Apr. 5, 2023
Seven Year Term Loan - Swapped to fixed [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 250,000	250,000
Effective interest rate		3.72%
Debt instrument maturity date		Oct. 1, 2022
$350M 3.95% Guaranteed Notes due 2023 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 350,000	350,000
Effective interest rate		3.87%
Debt instrument maturity date		Apr. 15, 2018
$250.0M 4.10% Guaranteed Notes due 2024 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 250,000	250,000
Effective interest rate		4.33%
Debt instrument maturity date		Feb. 15, 2023
$450.0M 3.95% Guaranteed Notes due 2027 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 450,000	450,000
Effective interest rate		4.03%
Debt instrument maturity date		Oct. 1, 2024
$250M 4.55% Guaranteed Notes due 2029 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 250,000	250,000
Effective interest rate		4.60%
Debt instrument maturity date		Oct. 1, 2029
Indenture IA (Preferred Trust I) [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 27,062	27,062
Debt instrument, description of variable rate basis		LIBOR + 1.25%
Spread on variable rate		1.25%
Debt instrument maturity date		Mar. 30, 2035
Indenture IB (Preferred Trust I) - Swapped to fixed [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 25,774	25,774
Effective interest rate		3.30%
Debt instrument maturity date		Apr. 30, 2035
Indenture II (Preferred Trust II) - Swapped to fixed [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 25,774	$ 25,774
Effective interest rate		3.09%
Debt instrument maturity date		Jul. 30, 2035
[1]	This loan was assumed upon acquisition of the related property on January 5, 2018. The interest rate reflects the market rate at the time of acquisition.

Debt Obligations (Textual) (Det

Debt Obligations (Textual) (Details)	Jul. 17, 2018USD ($)Extension	Sep. 30, 2018USD ($)	Dec. 31, 2017	Sep. 30, 2017USD ($)
Prior Revolving Credit Facilty [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	May 15, 2019	May 15, 2019
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate				2.34%
Commitment fee percentage		0.25%
Minimum fixed charge coverage ratio		1.5
Maximum leverage ratio		0.60
Maximum unsecured indebtedness to unencumbered asset value ratio		0.60
Maximum secured indebtedness to total asset value ratio		0.40
Minimum unencumbered cash flow to interest expense on unsecured debt ratio		1.75
Maximum percent of payments of dividends and distributions		95.00%
Line of Credit		$ 0		$ 178,000,000
Letters of credit outstanding amount				$ 13,500,000
Effective interest rate on credit facility				2.43%
Revolving Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage		0.125%
Revolving Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage		0.30%
Revolving Credit Facility [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.10%
Revolving Credit Facility [Member] | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.775%
Revolving Credit Facility [Member] | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.45%
Revolving Credit Facility [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		0.50%
Revolving Credit Facility [Member] | LIBOR for a One Month Period [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.00%
Revolving Credit Facility [Member] | LIBOR for a One Month Period [Member] | Minimum [Member]
Debt Instrument [Line Items]
Credit Spread on a LIBOR Rate Loan		0.00%
Revolving Credit Facility [Member] | LIBOR for a One Month Period [Member] | Maximum [Member]
Debt Instrument [Line Items]
Credit Spread on a LIBOR Rate Loan		0.45%
Revolving Credit Facility [Member] | New Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 600,000,000
Debt instrument maturity date	Jul. 15, 2022
Debt instrument, maturity extension period	6 months
Debt instrument, number of extensions | Extension	2
Debt financing costs	$ 2,700,000
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate		4.05%	4.04%

Debt Obligations - Aggregate Sc

Debt Obligations - Aggregate Scheduled Principal Payments of Debt Obligation, Excluding Amortization of Discounts and Premiums (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
2018 (three months remaining)	$ 1,854
2,019	7,595
2,020	87,226
2,021	15,143
2,022	256,332
Thereafter	1,585,346
Total principal payments	1,953,496
Net unamortized premiums/(discounts)	(6,031)
Net deferred financing costs	(9,928)
Total Debt Obligations	$ 1,937,537	$ 1,930,828

Fair Value of Financial Instr_3

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage notes payable, net		$ 322,588	$ 317,216
Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes receivable	[1],[2]	47,821	3,532
Carrying Amount [Member] | Unsecured Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Unsecured notes payable	[2]	1,287,661	1,286,573
Carrying Amount [Member] | Variable Rate Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate debt	[2]	327,288	327,039
Carrying Amount [Member] | Mortgages Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage notes payable, net	[2]	322,588	317,216
Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable, fair value	[1]	47,858	3,605
Fair Value [Member] | Unsecured Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		1,249,225	1,314,900
Fair Value [Member] | Variable Rate Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		310,640	308,872
Fair Value [Member] | Mortgages Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		$ 314,813	$ 304,665
[1]	The inputs to originate the notes receivable are unobservable and, as a result, are categorized as Level 3. The Company determined fair value by calculating the present value of the cash payments to be received through the maturity date of the loans.
[2]	T

Fair Value of Financial Instr_4

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Parenthetical) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	$ 9,928
Unsecured Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	9,483	$ 10,575
Unsecured Notes Payable [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	8,200	8,900
Variable Rate Debt [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	1,400	1,300
Mortgages Notes Payable [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	$ 400	$ 600

Fair Value of Financial Instr_5

Fair Value of Financial Instruments (Textual) (Details) - USD ($) $ in Millions	Jun. 26, 2018	Sep. 30, 2018
Third Party [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable		$ 3.4
Mortgage loans, interest rate through March 2019		7.00%
Mortgage loans, interest rate after March 2019 until maturity date in March of 2020		8.00%
Balloon payment expected to be received at the maturity date		$ 3.1
Mortgage loans scheduled maturity date		Mar. 1, 2020
Brandywine 1919 Ventures [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage loan	$ 44.4
Equity method investment, ownership percentage	50.00%
Mortgage loans scheduled maturity date	Jun. 25, 2023
Brandywine 1919 Ventures [Member] | Other Assets [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable	$ 44.4

Limited Partners' Non-Control_2

Limited Partners' Non-Controlling Interests in the Parent Company (Textual) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Noncontrolling Interest [Abstract]
Aggregate amount related to non-controlling interests classified within equity	$ 14.7	$ 15.2
Settlement value of non controlling interest in operating partnership	$ 23.3	$ 26.9

Fair Value of Derivative Fina_3

Fair Value of Derivative Financial Instruments - Terms and Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Notional Amount	$ 301,548	$ 301,548
3.718% Interest Rate Swap Maturing October 8, 2022 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Notional Amount	$ 250,000	250,000
Derivative, Fixed Interest Rate	3.718%
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	$ 12,178	5,694
3.300% Interest Rate Swap Maturing January 30, 2021 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Notional Amount	$ 25,774	25,774
Derivative, Fixed Interest Rate	3.30%
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	$ 546	25
3.090% Interest Rate Swap Maturing October30, 2019 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative Asset, Notional Amount	$ 25,774	25,774
Derivative, Fixed Interest Rate	3.09%
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	$ 277	$ 59

Beneficiaries Equity of the P_3

Beneficiaries Equity of the Parent Company - Number of Shares and Net Income Used to Calculate Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator
Net income (loss)	$ (43,262)	$ 19,046	$ 14,579	$ 48,015
Net (income) loss attributable to noncontrolling interests, Basic	339	(170)	(167)	(384)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(80)	(73)	(280)	(245)
Distribution to preferred shareholders	0	0	0	(2,032)
Preferred share redemption charge	0	0	0	(3,181)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	(43,003)	18,803	14,132	42,173
Net (income) loss attributable to noncontrolling interests, Diluted	339	(170)	(167)	(384)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(80)	(73)	(280)	(245)
Net income (loss) attributable to common shareholders, Diluted	$ (43,003)	$ 18,803	$ 14,132	$ 42,173
Denominator
Basic weighted average shares outstanding (in shares)	178,602,622	175,433,657	178,515,993	175,315,581
Contingent securities/Share based compensation (in shares)	0	1,401,365	1,236,551	1,283,751
Diluted weighted average shares outstanding (in shares)	178,602,622	176,835,022	179,752,544	176,599,332
Earnings (loss) per Common Share:
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.24)	$ 0.11	$ 0.08	$ 0.24

Beneficiaries Equity of the P_4

Beneficiaries Equity of the Parent Company (Textual) (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 11, 2018	Sep. 30, 2018	Sep. 30, 2017
Class of Stock [Line Items]
Dividends, Common Stock		$ 32.5
Dividends payable, date to be paid	Oct. 18, 2018
Dividends payable, date of record	Oct. 4, 2018
Preferred shares authorized		20,000,000	20,000,000
Preferred shares outstanding		0	0
Dividend Declared [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share	$ 0.18
Redeemable Common Limited Partnership Units [Member]
Class of Stock [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share		1,479,799	1,479,799

Partners Equity of the Operat_3

Partners Equity of the Operating Partnership - Number of Units and Net Income Used to Calculate Basic and Diluted Earnings Per Common Partnership Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Numerator
Net income	$ (43,262)	$ 19,046	$ 14,579	$ 48,015
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(80)	(73)	(280)	(245)
Distribution to preferred shareholders	0	0	0	(2,032)
Preferred share redemption charge	0	0	0	(3,181)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (80)	$ (73)	$ (280)	$ (245)
Denominator
Basic weighted average shares outstanding (in shares)	178,602,622	175,433,657	178,515,993	175,315,581
Contingent securities/Share based compensation (in shares)	0	1,401,365	1,236,551	1,283,751
Diluted weighted average shares outstanding (in shares)	178,602,622	176,835,022	179,752,544	176,599,332
Earnings (loss) per Common Partnership Unit:
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net income	$ (43,262)	$ 19,046	$ 14,579	$ 48,015
Net income attributable to noncontrolling interests	(20)	(12)	(46)	(25)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(80)	(73)	(280)	(245)
Distribution to preferred shareholders	0	0	0	(2,032)
Preferred share redemption charge	0	0	0	(3,181)
Net income (loss) attributable to common unitholders, Basic	(43,362)	18,961	14,253	42,532
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(80)	(73)	(280)	(245)
Net income (loss) attributable to common unitholders, Diluted	$ (43,362)	$ 18,961	$ 14,253	$ 42,532
Denominator
Basic weighted average shares outstanding (in shares)	180,082,421	176,913,456	179,995,792	176,795,380
Contingent securities/Share based compensation (in shares)	0	1,401,365	1,236,551	1,283,751
Diluted weighted average shares outstanding (in shares)	180,082,421	178,314,821	181,232,343	178,079,131
Earnings (loss) per Common Partnership Unit:
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.24)	$ 0.11	$ 0.08	$ 0.24
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.24)	$ 0.11	$ 0.08	$ 0.24

Partners Equity of the Operat_4

Partners Equity of the Operating Partnership (Textual) (Details) - USD ($) $ / shares in Units, $ in Millions	Sep. 11, 2018	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Common Partnership Unit [Line Items]
Dividends, Common Stock		$ 32.5
Dividends payable, date to be paid	Oct. 18, 2018
Dividends payable, date of record	Oct. 4, 2018
Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.18
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Dividends, Common Stock	$ 32.5
Dividends payable, date to be paid	Oct. 18, 2018
Dividends payable, date of record	Oct. 4, 2018
Preferred units authorized		20,000,000	20,000,000
Preferred units outstanding		0	0
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.18

Segment Information (Textual) (

Segment Information (Textual) (Details)	9 Months Ended
	Sep. 30, 2018segment
Segment Reporting [Abstract]
Number of Reportable Segments	5

Segment Information - Real Esta

Segment Information - Real Estate Investments, at Cost of Company's Reportable Segments (Details) - USD ($) $ in Thousands		Sep. 30, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating properties		$ 3,429,048	$ 3,832,348
Assets held for sale - real estate investments	[1]	396,072	0
Operating properties		3,825,120	3,832,348
Construction-in-progress		157,075	121,188
Land held for development	[2]	77,578	98,242
Prepaid leasehold interests in land held for development, net	[3]	40,100	0
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Operating properties		1,652,819	1,643,296
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Operating properties		979,068	958,796
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Operating properties	[1]	539,105	978,257
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Operating properties		170,912	163,653
Other [Member]
Segment Reporting Information [Line Items]
Operating properties		$ 87,144	$ 88,346
[1]	As of September 30, 2018, eight office properties in the Metropolitan Washington, D.C. segment were classified as held for sale. See Note 3, “Real Estate Investments,” for further information.
[2]	As of September 30, 2018, the Company categorized 37.9 acres of land held for development, comprised of 2.7 acres and 35.2 acres, located in the Pennsylvania Suburbs segment and Other segment, respectively, as held for sale in accordance with applicable accounting standards for long lived assets. As of December 31, 2017, the Company categorized 13.1 acres of land held for development, located in the Other segment, as held for sale in accordance with applicable accounting standards for long lived assets.
[3]	As of September 30, 2018, this caption comprised leasehold interests in prepaid 99-year ground leases at 3025 and 3001-3003 JFK Boulevard, in Philadelphia, Pennsylvania. See Note 3, “Real Estate Investments,”

Segment Information - Real Es_2

Segment Information - Real Estate Investments, at Cost of Company's Reportable Segments (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2018aproperty	Dec. 31, 2017a
Segment Reporting Information [Line Items]
Number of properties | property	93
3025 and 3001-3003 JFK Boulevard [Member]
Segment Reporting Information [Line Items]
Lease agreement term	99 years
Assets Held-for-sale [Member] | Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land | a	37.9
Assets Held-for-sale [Member] | Pennsylvania Suburbs [Member] | Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land | a	2.7
Assets Held-for-sale [Member] | Other [Member] | Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land | a	35.2	13.1
Office Properties [Member]
Segment Reporting Information [Line Items]
Number of properties | property	73
Office Properties [Member] | Assets Held-for-sale [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Number of properties | property	8

Segment Information - Net Opera

Segment Information - Net Operating Income of Company's Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Segment Reporting Information [Line Items]
Total revenue		$ 134,998		$ 128,438	$ 405,142		$ 387,149
Operating expenses	[1]	(52,878)		(50,701)	(161,929)		(152,400)
Net operating income (loss)		82,120		77,737	243,213		234,749
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Total revenue		64,352			190,478
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Total revenue		34,745			103,960
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Total revenue		22,754			69,012
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Total revenue		8,641			25,474
Other [Member]
Segment Reporting Information [Line Items]
Total revenue		3,707			13,187
Operating Segments [Member] | Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Total revenue		64,352		56,452	190,478		165,352
Operating expenses	[1]	(24,427)		(22,010)	(73,559)		(64,311)
Net operating income (loss)		39,925		34,442	116,919		101,041
Operating Segments [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Total revenue		34,745		34,861	103,960		105,673
Operating expenses	[1]	(11,937)		(11,846)	(37,018)		(35,670)
Net operating income (loss)		22,808		23,015	66,942		70,003
Operating Segments [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Total revenue		22,754		23,079	69,012		69,190
Operating expenses	[1]	(8,548)		(8,500)	(25,699)		(26,347)
Net operating income (loss)		14,206		14,579	43,313		42,843
Operating Segments [Member] | Austin, Texas [Member]
Segment Reporting Information [Line Items]
Total revenue		8,641		7,886	25,474		25,772
Operating expenses	[1]	(3,894)		(3,929)	(10,812)		(11,634)
Net operating income (loss)		4,747		3,957	14,662		14,138
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Total revenue		3,707		3,752	13,187		14,274
Operating expenses	[1]	(2,436)		(2,647)	(9,601)		(9,083)
Net operating income (loss)		1,271		1,105	3,586		5,191
Corporate [Member]
Segment Reporting Information [Line Items]
Total revenue		799	[2]	2,408	3,031	[2]	6,888
Operating expenses	[1]	(1,636)		(1,769)	(5,240)		(5,355)
Net operating income (loss)		$ (837)		$ 639	$ (2,209)		$ 1,533
[1]	Includes property operating expenses, real estate taxes and third party management expense.
[2]	Corporate includes intercompany eliminations necessary to reconcile to consolidated Company totals.

Segment Information - Unconsoli

Segment Information - Unconsolidated Real Estate Ventures of Company's Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		$ 167,782		$ 167,782		$ 194,621
Equity in income (loss) of real estate venture		1	$ (5,723)	(1,182)	$ (5,387)
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		20,544		20,544		39,939
Equity in income (loss) of real estate venture		(36)	134	(183)	113
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		0		0		3,503
Equity in income (loss) of real estate venture		0	24	0	448
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		119,032		119,032		119,817
Equity in income (loss) of real estate venture		(31)	(5,264)	(431)	(4,872)
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		14,411		14,411		13,973
Equity in income (loss) of real estate venture		423	(15)	1,156	1,266
MAP Venture [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	[1]	11,939		11,939		15,450
Equity in income (loss) of real estate venture	[1]	(444)	(706)	(2,011)	(2,610)
Other [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		1,856		1,856		$ 1,939
Equity in income (loss) of real estate venture		$ 89	$ 104	$ 287	$ 268
[1]	The MAP Venture represents a joint venture, formed on February 4, 2016 between the Company and MAP Ground Lease Holdings LLC, an affiliate of Och-Ziff Capital Management Group, LLC. The MAP Venture’s business operations, including properties in Richmond, Virginia; Metropolitan Washington, D.C.; New Jersey/Delaware and Pennsylvania Suburbs, are centrally managed with the results reported to management of the Company on a consolidated basis. As a result, the investment in the MAP Venture is separately presented. All other unconsolidated real estate ventures are managed consistently with the Company’s regional segments.

Segment Information - Reconcili

Segment Information - Reconciliation of Consolidated Net Income to Consolidated NOI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting [Abstract]
Net income (loss)	$ (43,262)	$ 19,046	$ 14,579	$ 48,015
Plus:
Interest expense	19,257	19,732	58,091	61,473
Interest expense - amortization of deferred financing costs	618	577	1,872	1,807
Depreciation and amortization	43,900	42,429	130,908	132,584
General and administrative expenses	5,963	5,813	22,209	21,797
Equity in (income) loss of Real Estate Ventures	(1)	5,723	1,182	5,387
Provision for impairment	56,865	0	56,865	3,057
Less:
Interest income	1,220	79	2,564	635
Income tax (provision) benefit	0	793	(158)	1,032
Net gain (loss) on disposition of real estate	0	0	(35)	8,411
Net gain on sale of undepreciated real estate	0	953	2,859	953
Net gain on Real Estate Venture transactions	0	13,758	37,263	28,340
Consolidated net operating income	$ 82,120	$ 77,737	$ 243,213	$ 234,749

Commitments and Contingencies_2

Commitments and Contingencies (Textual) (Details)	Aug. 23, 2018	May 18, 2018	Jul. 01, 2016USD ($)a	Dec. 03, 2015ft²	Apr. 02, 2015USD ($)	Sep. 30, 2018USD ($)Parcel	Mar. 16, 2018a	Oct. 13, 2017USD ($)	Apr. 28, 2017a	Jan. 30, 2017a
Subaru Build-to-Service Center Project [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms				18 years
Rentable Square Feet | ft²				83,000
Purchase option of lease from inception period	5 years			5 years
Estimated project costs						$ 47,600,000
Developer profit percentage		8.00%
Period following substantial completion of project to determine closing date		30 days
Period following completion of punch list items to determine closing date		3 days
Subaru Build-to-Service Center Project [Member] | Other Assets [Member]
Property Subject to or Available for Operating Lease [Line Items]
Project costs funded						34,500,000
Unconsolidated Real Estate Ventures [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness						664,200,000
PJP VII [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount						400,000
Real estate property debt						4,200,000
4040 Wilson Venture [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount						41,300,000
Loan total borrowing capacity						150,000,000
618 Market Street [Member]
Property Subject to or Available for Operating Lease [Line Items]
Contingent consideration, liability					$ 2,000,000	1,900,000
Fair value of contingent consideration					1,600,000
Interest expense					$ 2,000,000
One Drexel Plaza [Member]
Property Subject to or Available for Operating Lease [Line Items]
Expected excess redevelopment funding						37,300,000
Estimated aggregate cost						83,100,000
Acquisition cost, inclusive in estimated aggregate cost								$ 37,800,000
Schuylkill Yards [Member]
Property Subject to or Available for Operating Lease [Line Items]
Required spending in capital improvements to property						2,700,000
Estimated potential additional contribution obligation						$ 700,000
Garza Land Acquisition [Member]
Property Subject to or Available for Operating Lease [Line Items]
Acreage of land | a			34.6
Gross purchase value of assets			$ 20,600,000
Number of Parcels | Parcel						3
Garza Land Acquisition [Member] | Parcel One [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of land sold | a									8.4
Garza Land Acquisition [Member] | Parcel Two [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of land sold | a										1.7
Garza Land Acquisition [Member] | Parcel Three [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of land sold | a							6.6
Minimum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms						10 years
Minimum [Member] | One Drexel Plaza [Member]
Property Subject to or Available for Operating Lease [Line Items]
Required spending in capital improvements to property						$ 8,000,000
Maximum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms						66 years
Mortgage Lenders [Member]
Property Subject to or Available for Operating Lease [Line Items]
Associated letter of credit						$ 0

Commitments and Contingencies -

Commitments and Contingencies - Minimum Future Rental Payments on Non-cancelable Leases (Details) $ in Thousands	Sep. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2018 (three months remaining)	$ 306
2,019	1,222
2,020	1,222
2,021	1,222
2,022	1,222
Thereafter	56,911
Total	$ 62,105

Subsequent Events (Textual) (De

Subsequent Events (Textual) (Details) $ in Millions	Oct. 17, 2018USD ($)ft²property	Oct. 16, 2018USD ($)ft²property	Sep. 30, 2018USD ($)ft²	Sep. 30, 2018USD ($)ft²	Sep. 30, 2017
Subsequent Event [Line Items]
Net Rentable Square Feet | ft²			16,462,764	16,462,764
DRA Austin Venture [Member]
Subsequent Event [Line Items]
Equity method investment, ownership percentage			50.00%	50.00%	50.00%
Investment in real estate venture			$ 14.4	$ 14.4
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member]
Subsequent Event [Line Items]
Impairment on assets held for sale			$ 56.9
Subsequent Event [Member] | DRA Austin Venture [Member]
Subsequent Event [Line Items]
Net Rentable Square Feet | ft²	1,570,123
Percentage of ownership interest to be acquired	50.00%
Number of real estate property to be acquired | property	12
Purchase price to be transferred to acquire real estate properties	$ 537
Mortgage debt to be assumed in connection with acquisition of real estate properties	$ 245.8
Subsequent Event [Member] | Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan Washington, D.C. - Office [Member]
Subsequent Event [Line Items]
Number of properties to be sold | property		8
Net Rentable Square Feet | ft²		1,293,197
Sales Price		$ 312
Equity method investment, ownership percentage		15.00%
Net proceeds received from real estate venture transactions		$ 292
Impairment on assets held for sale				$ 56.9