Brandywine Realty Trust (BDN) 10-Q 26 Apr 18 2018 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information Document - shares	3 Months Ended
	Mar. 31, 2018	Apr. 20, 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
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		178,530,101
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
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Real estate investments:
Operating properties		$ 3,864,706	$ 3,832,348
Accumulated depreciation		(920,207)	(895,091)
Operating real estate investments, net		2,944,499	2,937,257
Construction-in-progress		129,413	121,188
Land held for development	[1]	99,436	98,242
Total real estate investments, net		3,173,348	3,156,687
Assets held for sale, net		0	392
Cash and cash equivalents		200,813	202,179
Accounts receivable, net of allowance of $3,935 and $3,467 as of March 31, 2018 and December 31, 2017, respectively		17,794	17,938
Accrued rent receivable, net of allowance of $13,409 and $13,645 as of March 31, 2018 and December 31, 2017, respectively		174,236	169,760
Investment in Real Estate Ventures, equity method		171,383	194,621
Deferred costs, net		97,299	96,695
Intangible assets, net		63,614	64,972
Other assets		139,449	92,204
Total assets		4,037,936	3,995,448
LIABILITIES AND EQUITY
Mortgage notes payable, net		325,974	317,216
Unsecured term loans, net		248,512	248,429
Unsecured senior notes, net		1,365,546	1,365,183
Accounts payable and accrued expenses		105,176	107,074
Distributions payable		32,502	32,456
Deferred income, gains and rent		58,887	42,593
Acquired lease intangibles, net		19,510	20,274
Other liabilities		14,588	15,623
Total liabilities		2,170,695	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; 178,442,517 and 178,285,236 issued and outstanding as of March 31, 2018 and December 31, 2017, respectively		1,785	1,784
Additional paid-in-capital		3,222,047	3,218,564
Deferred compensation payable in common shares		13,506	12,445
Common shares in grantor trust, 948,592 and 894,736 as of March 31, 2018 and December 31, 2017, respectively		(13,506)	(12,445)
Cumulative earnings		704,506	660,174
Accumulated other comprehensive income		7,365	2,399
Cumulative distributions		(2,086,000)	(2,053,741)
Total Brandywine Realty Trust's equity		1,849,703	1,829,180
Noncontrolling interests		17,538	17,420
Total beneficiaries' equity		1,867,241	1,846,600
Total liabilities and beneficiaries' equity		4,037,936	3,995,448
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Operating properties		3,864,706	3,832,348
Accumulated depreciation		(920,207)	(895,091)
Operating real estate investments, net		2,944,499	2,937,257
Construction-in-progress		129,413	121,188
Land held for development		99,436	98,242
Total real estate investments, net		3,173,348	3,156,687
Assets held for sale, net		0	392
Cash and cash equivalents		200,813	202,179
Accounts receivable, net of allowance of $3,935 and $3,467 as of March 31, 2018 and December 31, 2017, respectively		17,794	17,938
Accrued rent receivable, net of allowance of $13,409 and $13,645 as of March 31, 2018 and December 31, 2017, respectively		174,236	169,760
Investment in Real Estate Ventures, equity method		171,383	194,621
Deferred costs, net		97,299	96,695
Intangible assets, net		63,614	64,972
Other assets		139,449	92,204
Total assets		4,037,936	3,995,448
LIABILITIES AND EQUITY
Mortgage notes payable, net		325,974	317,216
Unsecured term loans, net		248,512	248,429
Unsecured senior notes, net		1,365,546	1,365,183
Accounts payable and accrued expenses		105,176	107,074
Distributions payable		32,502	32,456
Deferred income, gains and rent		58,887	42,593
Acquired lease intangibles, net		19,510	20,274
Other liabilities		14,588	15,623
Total liabilities		2,170,695	2,148,848
Commitments and contingencies
Redeemable limited partnership units at redemption value; 1,479,799 issued and outstanding in as of September 30, 2017 and December 31, 2016		23,049	26,918
Equity:
General Partnership Capital; 175,477,498 and 175,140,760 units issued and outstanding as of September 30, 2017 and December 31, 2016, respectively		1,834,947	1,815,411
Accumulated other comprehensive income		7,064	2,056
Total Brandywine Operating Partnership, L.P.'s equity		1,842,011	1,817,467
Non-controlling interest - consolidated real estate ventures		2,181	2,215
Total partners' equity		1,844,192	1,819,682
Total liabilities and beneficiaries' equity		$ 4,037,936	$ 3,995,448
[1]	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.

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Accounts receivable, allowance	$ 3,935	$ 3,467
Accrued rent receivable, allowance	$ 13,409	$ 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	178,442,517	178,285,236
Common Stock, Shares, Outstanding	178,442,517	178,285,236
Common Shares in Grantor Trust	948,592	894,736
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Accounts receivable, allowance	$ 3,935	$ 3,467
Accrued rent receivable, allowance	$ 13,409	$ 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	178,442,517	178,285,236
General Partners' Capital Account, Units Outstanding	178,442,517	178,285,236

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue
Rents	$ 106,360	$ 103,332
Tenant reimbursements	19,849	18,535
Termination fees	550	1,673
Third party management fees, labor reimbursement and leasing	7,674	6,485
Other	1,925	895
Total revenue	136,358	130,920
Operating expenses
Property operating expenses	39,332	36,885
Real estate taxes	12,422	11,749
Third party management expenses	4,750	2,447
Depreciation and amortization	43,291	45,892
General and administrative expenses	8,723	9,325
Provision for impairment	0	2,730
Total operating expenses	108,518	109,028
Operating income	27,840	21,892
Other income (expense)
Interest income	703	393
Interest expense	(19,533)	(21,437)
Interest expense - amortization of deferred financing costs	(627)	(634)
Equity in loss of Real Estate Ventures	(825)	(748)
Net gain on disposition of real estate	0	7,323
Net gain on sale of undepreciated real estate	22	0
Net gain on Real Estate Venture transactions	37,263	14,582
Net income before income taxes	44,843	21,371
Income tax provision	(138)	(100)
Net income	44,705	21,271
Net income attributable to noncontrolling interests	(376)	(169)
Net income attributable to Brandywine Realty Trust	44,329	21,102
Distribution to preferred shareholders	0	(1,725)
Nonforfeitable dividends allocated to unvested restricted shareholders	(114)	(99)
Net income attributable to Common Shareholders of Brandywine Realty Trust	$ 44,215	$ 19,278
Basic income per Common Share	$ 0.25	$ 0.11
Diluted income per Common Share	$ 0.25	$ 0.11
Basic weighted average shares outstanding	178,395,525	175,176,964
Diluted weighted average shares outstanding	179,788,311	176,201,872
Distributions declared per Common Share	$ 0.18	$ 0.16
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Rents	$ 106,360	$ 103,332
Tenant reimbursements	19,849	18,535
Termination fees	550	1,673
Third party management fees, labor reimbursement and leasing	7,674	6,485
Other	1,925	895
Total revenue	136,358	130,920
Operating expenses
Property operating expenses	39,332	36,885
Real estate taxes	12,422	11,749
Third party management expenses	4,750	2,447
Depreciation and amortization	43,291	45,892
General and administrative expenses	8,723	9,325
Provision for impairment	0	2,730
Total operating expenses	108,518	109,028
Operating income	27,840	21,892
Other income (expense)
Interest income	703	393
Interest expense	(19,533)	(21,437)
Interest expense - amortization of deferred financing costs	(627)	(634)
Equity in loss of Real Estate Ventures	(825)	(748)
Net gain on disposition of real estate	0	7,323
Net gain on sale of undepreciated real estate	22	0
Net gain on Real Estate Venture transactions	37,263	14,582
Net income before income taxes	44,843	21,371
Income tax provision	(138)	(100)
Net income	44,705	21,271
Net income from continuing operations attributable to non-controlling interests - consolidated real estate ventures	(5)	(5)
Net income attributable to Brandywine Realty Trust	44,700	21,266
Distribution to preferred shareholders	0	(1,725)
Nonforfeitable dividends allocated to unvested restricted shareholders	(114)	(99)
Net income attributable to Common Shareholders of Brandywine Realty Trust	$ 44,586	$ 19,442
Basic income per Common Share	$ 0.25	$ 0.11
Diluted income per Common Share	$ 0.25	$ 0.11
Basic weighted average shares outstanding	179,875,324	176,656,763
Diluted weighted average shares outstanding	181,268,110	177,681,671
Distributions declared per Common Share	$ 0.18	$ 0.16

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Net income		$ 44,705	$ 21,271
Comprehensive income:
Unrealized gain on derivative financial instruments		4,696	1,014
Amortization of interest rate contracts	[1]	312	286
Total comprehensive income		5,008	1,300
Comprehensive income		49,713	22,571
Comprehensive income attributable to noncontrolling interest		(418)	(181)
Comprehensive income attributable to reporting entity		49,295	22,390
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Net income		44,705	21,271
Comprehensive income:
Unrealized gain on derivative financial instruments		4,696	1,014
Amortization of interest rate contracts	[1]	312	286
Total comprehensive income		5,008	1,300
Comprehensive income		49,713	22,571
Comprehensive income attributable to noncontrolling interest		(5)	(5)
Comprehensive income attributable to reporting entity		$ 49,708	$ 22,566
[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	21,271						21,102			169
Other comprehensive income	1,300							1,288		12
Issuance of partnership interest in consolidated real estate venture	29									29
Equity issuance costs	(219)				(219)
Bonus share issuance	110				110
Bonus share issuance, Shares			6,752
Share-based compensation activity	3,770				3,769		1
Share-based compensation activity, Shares			56,669	39,870
Share Issuance from/(to) Deferred Compensation Plan	(48)			$ 560	(48)	(560)
Share Issuance from/(to) Deferred Compensation Plan, Shares			(354)	(2,388)
Share Choice Plan Issuance, Shares			(1,423)
Reallocation of Noncontrolling interest					(23)					23
Preferred Share distributions	(1,725)								(1,725)
Distributions declared	(28,359)								(28,122)	(237)
Ending Balance at Mar. 31, 2017	1,879,566	$ 40	$ 1,752	$ 14,244	3,262,459	(14,244)	560,422	(457)	(1,961,739)	17,089
Ending Balance, Shares at Mar. 31, 2017		4,000,000	175,202,404	936,939
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	44,705						44,329			376
Other comprehensive income	5,008							4,966		42
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 venture	15									15
Distributions from consolidated real estate venture	(54)									(54)
Share-based compensation activity	3,076		$ 1		3,072		3
Share-based compensation activity, Shares			68,425
Share Issuance from/(to) Deferred Compensation Plan				$ 1,061		(1,061)
Share Issuance from/(to) Deferred Compensation Plan, Shares			66,830	53,856
Share Choice Plan Issuance, Shares			(1,285)
Reallocation of Noncontrolling interest					(5)					5
Preferred Share distributions	0
Distributions declared	(32,525)								(32,259)	(266)
Ending Balance at Mar. 31, 2018	$ 1,867,241		$ 1,785	$ 13,506	$ 3,222,047	$ (13,506)	$ 704,506	$ 7,365	$ (2,086,000)	$ 17,538
Ending Balance, Shares at Mar. 31, 2018			178,442,517	948,592

Consolidated Statements of Ben7

Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Distributions declared per Common Share	$ 0.18	$ 0.16
Cumulative Distributions [Member]
Distributions declared per Common Share	0.18	0.16
Noncontrolling Interest [Member]
Distributions declared per Common Share	$ 0.18	$ 0.16

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities:
Net income	$ 44,705	$ 21,271
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	43,291	45,892
Amortization of deferred financing costs	627	634
Amortization of debt discount/(premium), net	176	362
Amortization of stock compensation costs	3,265	3,124
Straight-line rent income	(4,978)	(5,895)
Amortization of acquired above (below) market leases, net	(793)	(1,338)
Straight-line ground rent expense	22	22
Provision for doubtful accounts	467	707
Net gain on real estate venture transactions	(37,263)	(14,582)
Net gain on sale of interests in real estate	(22)	(7,323)
Provision for impairment	0	2,730
Income from Real Estate Ventures, net of distributions	2,209	748
Income tax provision	138	100
Changes in assets and liabilities:
Accounts receivable	(646)	(917)
Other assets	(12,911)	(10,626)
Accounts payable and accrued expenses	(1,146)	9,089
Deferred income, gains and rent	2,295	(3,333)
Other liabilities	(738)	(106)
Net cash provided by operating activities	38,698	40,559
Cash flows from investing activities:
Acquisition of properties	(24,946)	0
Proceeds from the sale of properties	14,921	74,159
Proceeds from real estate venture sales	42,953	27,230
Proceeds from repayment of mortgage notes receivable	562	0
Capital expenditures for tenant improvements	(16,569)	(11,408)
Capital expenditures for redevelopments	(2,429)	(5,505)
Capital expenditures for developments	(19,387)	(21,156)
Advances for the purchase of tenant assets, net of repayments	316	997
Investment in unconsolidated Real Estate Ventures	(261)	(4,910)
Deposits for real estate	(162)	268
Capital distributions from Real Estate Ventures	1,951	8,306
Leasing costs paid	(3,120)	(4,129)
Net cash (used in) provided by investing activities	(6,171)	63,852
Cash flows from financing activities:
Repayments of mortgage notes payable	(1,317)	(1,215)
Proceeds from the issuance of common shares	416	0
Shares used for employee taxes upon vesting of share awards	(942)	(129)
Partner contributions to consolidated real estate venture	15	29
Partner distributions from consolidated real estate venture	(54)	0
Distributions paid to shareholders	(32,173)	(29,815)
Distributions to noncontrolling interest	(266)	(237)
Net cash used in financing activities	(34,321)	(31,367)
Increase (decrease) in cash and cash equivalents and restricted cash	(1,794)	73,044
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	201,648	267,662
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the three months ended March 31, 2018 and 2017 of $687 and $1,709, respectively	12,705	11,268
Cash paid for income taxes	7	0
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	32,502	30,047
Change in investment in real estate ventures as a result of dispositions	(17,313)	(12,549)
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	(1,112)	1,273
Change in capital expenditures financed through retention payable at period end	(792)	(199)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income	44,705	21,271
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	43,291	45,892
Amortization of deferred financing costs	627	634
Amortization of debt discount/(premium), net	176	362
Amortization of stock compensation costs	3,265	3,124
Straight-line rent income	(4,978)	(5,895)
Amortization of acquired above (below) market leases, net	(793)	(1,338)
Straight-line ground rent expense	22	22
Provision for doubtful accounts	467	707
Net gain on real estate venture transactions	(37,263)	(14,582)
Net gain on sale of interests in real estate	(22)	(7,323)
Provision for impairment	0	2,730
Income from Real Estate Ventures, net of distributions	2,209	748
Income tax provision	138	100
Changes in assets and liabilities:
Accounts receivable	(646)	(917)
Other assets	(12,911)	(10,626)
Accounts payable and accrued expenses	(1,146)	9,089
Deferred income, gains and rent	2,295	(3,333)
Other liabilities	(738)	(106)
Net cash provided by operating activities	38,698	40,559
Cash flows from investing activities:
Acquisition of properties	(24,946)	0
Proceeds from the sale of properties	14,921	74,159
Proceeds from real estate venture sales	42,953	27,230
Proceeds from repayment of mortgage notes receivable	562	0
Capital expenditures for tenant improvements	(16,569)	(11,408)
Capital expenditures for redevelopments	(2,429)	(5,505)
Capital expenditures for developments	(19,387)	(21,156)
Advances for the purchase of tenant assets, net of repayments	316	997
Investment in unconsolidated Real Estate Ventures	(261)	(4,910)
Deposits for real estate	(162)	268
Capital distributions from Real Estate Ventures	1,951	8,306
Leasing costs paid	(3,120)	(4,129)
Net cash (used in) provided by investing activities	(6,171)	63,852
Cash flows from financing activities:
Repayments of mortgage notes payable	(1,317)	(1,215)
Proceeds from the issuance of common shares	416	0
Shares used for employee taxes upon vesting of share awards	(942)	(129)
Partner contributions to consolidated real estate venture	15	29
Partner distributions from consolidated real estate venture	(54)	0
Distributions paid to shareholders	(32,439)	(30,052)
Net cash used in financing activities	(34,321)	(31,367)
Increase (decrease) in cash and cash equivalents and restricted cash	(1,794)	73,044
Cash and cash equivalents and restricted cash at beginning of year	203,442	193,919
Cash and cash equivalents and restricted cash at end of period	201,648	266,963
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the three months ended March 31, 2018 and 2017 of $687 and $1,709, respectively	12,705	11,268
Cash paid for income taxes	7	0
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	32,502	30,047
Change in investment in real estate ventures as a result of dispositions	(17,313)	(12,549)
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	(1,112)	1,273
Change in capital expenditures financed through retention payable at period end	$ (792)	$ (199)

Consolidated Statements of Cas9

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Capitalized interest	$ 687	$ 1,709
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Capitalized interest	$ 687	$ 1,709

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	$ 21,271		$ 169	21,271	$ 21,266		5
Other comprehensive income	1,300	$ 1,288	12	1,300		1,300
Share Issuance from/(to) Deferred Compensation Plan	(48)			(48)	$ (48)
Share Issuance from/(to) Deferred Compensation Plan, Shares					354
Issuance of LP Units				(219)	$ (219)
Issuance of partnership interest in consolidated real estate venture	29		29	29			29
Share Choice Plan Issuance, Shares					(1,423)
Bonus share issuance	110			110	$ 110
Bonus share issuance, Shares					6,752
Share-based compensation activity	3,770			3,769	$ 3,769
Share-based compensation activity, Shares					56,669
Adjustment of redeemable partnership units to liquidation value at period end				(340)	$ (340)
Preferred Share distributions	(1,725)			(1,725)	(1,725)
Distributions to general partnership unitholders				(28,122)	(28,122)
Ending Balance at Mar. 31, 2017				1,855,667	$ 1,757,455	(822)	2,184	$ 96,850
Ending Balance, Shares at Mar. 31, 2017					175,202,404			4,000,000
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	44,705		376	44,705	$ 44,700		5
Other comprehensive income	5,008	$ 4,966	42	5,008		5,008
Share Issuance from/(to) Deferred Compensation Plan, Shares					(66,830)
Issuance of LP Units				416	$ 416
Issuance of LP Units, Shares					23,311
Issuance of partnership interest in consolidated real estate venture	15		15	15			15
Distributions from consolidated real estate venture	(54)		$ (54)	(54)			(54)
Share Choice Plan Issuance, Shares					(1,285)
Share-based compensation activity	3,076			3,075	$ 3,075
Share-based compensation activity, Shares					68,425
Adjustment of redeemable partnership units to liquidation value at period end				3,604	$ 3,604
Preferred Share distributions	$ 0			0
Distributions to general partnership unitholders				(32,259)	(32,259)
Ending Balance at Mar. 31, 2018				$ 1,844,192	$ 1,834,947	$ 7,064	$ 2,181
Ending Balance, Shares at Mar. 31, 2018					178,442,517

Consolidated Statements of Pa11

Consolidated Statements of Partners' Equity (Parenthetical) - BRANDYWINE OPERATING PARTNERSHIP, L.P. - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Distributions to general partnership unitholders (USD per share)	$ 0.18	$ 0.16
General Partner Capital [Member]
Distributions to general partnership unitholders (USD per share)	$ 0.18	$ 0.16

Organization of the Parent Comp

Organization of the Parent Company and The Operating Partnership	3 Months Ended
	Mar. 31, 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 March 31, 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 March 31, 2018, the Company owned 94 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 March 31, 2018, excludes two development properties and four redevelopment properties under construction or committed for construction (collectively, the “Core Properties”). The Properties were comprised of the following as of March 31, 2018: Number of Properties Rentable Square Feet Office properties 82 15,004,862 Mixed-use properties 5 646,741 Retail properties 1 17,884 Core Properties 88 15,669,487 Development properties 2 247,818 Redevelopment properties 4 583,719 The Properties 94 16,501,024 In addition, as of March 31, 2018, the Company owned land held for development, comprised of 200 acres of undeveloped land and held options to purchase approximately 59 additional acres of undeveloped land. As of March 31, 2018, the total potential development that these land parcels could support under current zoning and entitlements, including the parcels under option, amounted to an estimated 14.7 million square feet. The Properties and the properties owned by the Real Estate Ventures are located in or near Philadelphia, Pennsylvania; Metropolitan Washington, D.C.; Southern New Jersey; Wilmington, Delaware and Austin, Texas. In addition to managing properties that the Company owns, as of March 31, 2018, the Company was managing approximately 8.8 million net rentable square feet of office and industrial properties for third parties and Real Estate Ventures. The Company conducts its third-party real estate management services business primarily through wholly-owned management company subsidiaries. As of March 31, 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	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
BASIS OF PRESENTATION	ERROR: Could not retrieve Word content for note block

Real Estate Investments

Real Estate Investments	3 Months Ended
	Mar. 31, 2018
Real Estate [Abstract]
REAL ESTATE INVESTMENTS	3. REAL ESTATE INVESTMENTS As of March 31, 2018 and December 31, 2017, the gross carrying value of the properties was as follows (in thousands): March 31, December 31, 2018 2017 Land $ 498,197 $ 492,197 Building and improvements 2,915,399 2,896,113 Tenant improvements 451,110 444,038 Total $ 3,864,706 $ 3,832,348 Acquisitions 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 capitalized $0.3 million of costs related to entering the lease in accordance with ASC 840. Based on the Company’s evaluation under ASC 840, the ground lease was classified as an operating lease and included in the “Other assets” caption in the consolidated balance sheets. On January 5, 2018, the Company acquired, from its real estate venture partner in both the Four Tower Bridge real estate venture and the Seven Tower Bridge real estate venture, the remaining 35% ownership interest in the Four Tower Bridge real estate venture through a nonmonetary 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. The acquisition of the remaining 35% ownership interest of Four Tower Bridge 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 utilized 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 of revenue and $0.1 million of net income, included in the Company’s consolidated income statements, for the period from January 5, 2018 through March 31, 2018. Dispositions The Company sold the following land parcels during the three-month period ended March 31, 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 $ - (a) January 10, 2018 Westpark Land Durham, NC 1 13.1 485 412 22 Total Dispositions 2 19.7 $ 15,056 $ 14,921 $ 22 (a) The Company has a continuing involvement, through a completion guarantee, which requires the Company as developer to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The Company does not transfer control of the land parcel until the infrastructure improvements are complete and the guarantee is released. Accordingly, the cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets and the Company will recognize the sale once the infrastructure improvements are complete. See Note 14, “Commitments and Contingencies,” for further discussion of the infrastructure improvements. The sale of land referenced above does 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.

Investment in Unconsolidated Re

Investment in Unconsolidated Real Estate Ventures	3 Months Ended
	Mar. 31, 2018
Equity Method Investments And Joint Ventures [Abstract]
INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES	4. INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES As of March 31, 2018, the Company held ownership interests in 10 unconsolidated Real Estate Ventures for an aggregate investment balance of $171.4 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 March 31, 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 $1.3 million and $1.5 million for the three-month periods ended March 31, 2018 and March 31, 2017, respectively. The Company earned leasing commission income from its Real Estate Ventures of $0.8 million and $1.3 million for the three-month periods ended March 31, 2018 and March 31, 2017, respectively. The Company had outstanding accounts receivable balances from its Real Estate Ventures of $1.4 million and $0.9 million as of March 31, 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 March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) (a) Other Total Net property $ 263,384 $ 159,159 $ - $ 488,224 $ 910,767 Other assets 35,080 24,520 - 84,092 143,692 Other liabilities 17,189 4,844 - 72,129 94,162 Debt, net 247,844 92,813 - 294,662 635,319 Equity (b) 33,431 86,022 - 205,525 324,978 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, evo at Cira 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-month periods ended March 31, 2018 and 2017 (in thousands): Three-month period ended March 31, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 14,356 $ 5,836 $ 995 $ 21,634 $ 42,821 Operating expenses (6,066 ) (2,544 ) (250 ) (11,908 ) (20,768 ) Interest expense, net (2,294 ) (864 ) (388 ) (4,580 ) (8,126 ) Depreciation and amortization (5,698 ) (2,137 ) (376 ) (6,173 ) (14,384 ) Loss on early extinguishment of debt - - (718 ) - (718 ) Net income (loss) $ 298 $ 291 $ (737 ) $ (1,027 ) $ (1,175 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 149 $ 146 $ (369 ) $ (632 ) $ (706 ) Basis adjustments and other (69 ) 15 11 (76 ) (119 ) Equity in income (loss) of Real Estate Ventures $ 80 $ 161 $ (358 ) $ (708 ) $ (825 ) Three-month period ended March 31, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 21,552 $ 7,325 $ 3,154 $ 22,248 $ 54,279 Operating expenses (9,313 ) (2,940 ) (679 ) (12,234 ) (25,166 ) Interest expense, net (3,689 ) (1,145 ) (898 ) (5,098 ) (10,830 ) Depreciation and amortization (9,229 ) (2,809 ) (1,128 ) (7,595 ) (20,761 ) Net income (loss) $ (679 ) $ 431 $ 449 $ (2,679 ) $ (2,478 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ (340 ) $ 216 $ 225 $ (1,262 ) $ (1,161 ) Basis adjustments and other (25 ) 310 7 121 413 Equity in income (loss) of Real Estate Ventures $ (365 ) $ 526 $ 232 $ (1,141 ) $ (748 ) (a) The Company’s unconsolidated ownership interests ranged from 25% to 70% during the three-month periods ended March 31, 2018 and 20% to 70% during the three-month period ended March 31, 2017, subject to specified priority allocations of distributable cash in certain of the Real Estate Ventures. Four Tower Bridge Acquisition On January 5, 2018, the Company acquired, from its real estate venture partner in both the Four Tower Bridge real estate venture and the Seven Tower Bridge real estate venture, the remaining 35% ownership interest in the Four Tower Bridge real estate venture through a nonmonetary 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 March 31, 2018, the Real Estate Ventures had aggregate indebtedness to third parties of $639.3 million. These loans are generally mortgage or construction loans, most of which are non-recourse to the Company. As of March 31, 2018, the loans for which there is recourse to the Company consist of the following: (

Intangible Assets and Liabiliti

Intangible Assets and Liabilities	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS AND LIABILITIES	5. INTANGIBLE ASSETS AND LIABILITIES As of March 31, 2018 and December 31, 2017, the Company’s intangible assets/liabilities were comprised of the following (in thousands): March 31, 2018 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 106,574 $ (46,495 ) $ 60,079 Tenant relationship value 10,593 (9,064 ) 1,529 Above market leases acquired 4,712 (2,706 ) 2,006 Total intangible assets, net $ 121,879 $ (58,265 ) $ 63,614 Acquired lease intangibles, net: Below market leases acquired $ 35,719 $ (16,209 ) $ 19,510 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 March 31, 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 (nine months remaining) $ 11,483 $ 2,648 2019 13,130 2,847 2020 10,452 2,081 2021 7,538 1,432 2022 5,355 1,264 Thereafter 15,656 9,238 Total $ 63,614 $ 19,510

Debt Obligations

Debt Obligations	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
DEBT OBLIGATIONS	6. DEBT OBLIGATIONS The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Effective Interest Rate Maturity Date MORTGAGE DEBT: Two Logan Square $ 84,037 $ 84,440 3.98% May 2020 Four Tower Bridge 9,695 - 4.50% (a) Feb 2021 One Commerce Square 122,808 123,667 3.64% Apr 2023 Two Commerce Square 112,000 112,000 4.51% Apr 2023 Principal balance outstanding 328,540 320,107 Plus: fair market value premium (discount), net (2,041 ) (2,325 ) Less: deferred financing costs (525 ) (566 ) Mortgage indebtedness $ 325,974 $ 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 (4,341 ) (4,423 ) Less: deferred financing costs (10,211 ) (10,575 ) Total unsecured indebtedness $ 1,614,058 $ 1,613,612 Total Debt Obligations $ 1,940,032 $ 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 March 31, 2018 and December 31, 2017, In addition to the debt described above, the Company utilizes its four-year unsecured revolving credit facility (the “Credit Facility”) borrowings for general business purposes, including to fund costs of acquisitions, developments and redevelopments of properties, fund share repurchases and to repay from time to time other debt. The Credit Facility provides for borrowings of up to $600.0 million and the per annum variable interest rate on borrowings is LIBOR plus 1.20%. The interest rate and facility fee are subject to adjustment upon a change in the Company’s unsecured debt ratings. The Company had as of and during either of the three-month periods ended March 31, 2018 and March 31, 2017. 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 March 31, 2018. Management continuously monitors the Company’s compliance with and anticipated compliance with the covenants. Certain of the covenants restrict the Company’s ability to obtain alternative sources of capital. As of March 31, 2018, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2018 (nine months remaining) $ 5,508 2019 7,595 2020 87,226 2021 15,143 2022 256,332 Thereafter 1,585,346 Total principal payments 1,957,150 Net unamortized premiums/(discounts) (6,382 ) Net deferred financing costs (10,736 ) Outstanding indebtedness $ 1,940,032

Fair Value of Financial Instrum

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 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 March 31, 2018 and December 31, 2017, respectively. The discount rate used in calculating fair value is the sum of the current 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 are 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 amounts reflected in the consolidated balance sheets at March 31, 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 and accrued expenses. The following are financial instruments for which the Company’s estimates of fair value differ from the carrying amounts (in thousands): March 31, 2018 December 31, 2017 Carrying Amount (a) Fair Value Carrying Amount (a) Fair Value Unsecured notes payable $ 1,286,936 $ 1,284,180 $ 1,286,573 $ 1,314,900 Variable rate debt $ 327,122 $ 309,577 $ 327,039 $ 308,872 Mortgage notes payable $ 325,974 $ 312,402 $ 317,216 $ 304,665 Note receivable $ 3,490 $ 3,565 $ 3,532 $ 3,605 (a) In April 2015, the FASB issued guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of the corresponding debt liability, consistent with debt discounts. As a result, the carrying amounts presented in the table above are net of deferred financing costs of $8.7 million and $8.9 million for unsecured notes payable, $1.5 million and $1.6 million for variable rate debt and $0.5 million and $0.6 million for mortgage notes payable as of March 31, 2018 and December 31, 2017, respectively. 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 March 31, 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 note 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 loan. 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 March 31, 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 March 31, 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	3 Months Ended
	Mar. 31, 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 $15.4 million and $15.2 million as of March 31, 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 March 31, 2018 and December 31, 2017, was approximately $23.5 million and $26.9 million, respectively.

Fair Value of Derivative Financ

Fair Value of Derivative Financial Instruments	3 Months Ended
	Mar. 31, 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 March 31, 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 3/31/2018 12/31/2017 3/31/2018 12/31/2017 Assets Swap Interest Rate Cash Flow (a) $ 250,000 $ 250,000 3.718 % October 8, 2015 October 8, 2022 $ 9,763 $ 5,694 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 360 25 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 242 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	3 Months Ended
	Mar. 31, 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 March 31, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 44,705 $ 44,705 $ 21,271 $ 21,271 Net income attributable to noncontrolling interests (376 ) (376 ) (169 ) (169 ) Nonforfeitable dividends allocated to unvested restricted shareholders (114 ) (114 ) (99 ) (99 ) Preferred share dividends - - (1,725 ) (1,725 ) Net income attributable to common shareholders $ 44,215 $ 44,215 $ 19,278 $ 19,278 Denominator Weighted-average shares outstanding 178,395,525 178,395,525 175,176,964 175,176,964 Contingent securities/Share based compensation - 1,392,786 - 1,024,908 Weighted-average shares outstanding 178,395,525 179,788,311 175,176,964 176,201,872 Earnings per Common Share: Net income attributable to common shareholders $ 0.25 $ 0.25 $ 0.11 $ 0.11 Redeemable common limited partnership units totaling 1,479,799 at both March 31, 2018 and March 31, 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-month periods ended March 31, 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 February 28, 2018, the Parent Company declared a distribution of $0.18 per common share, totaling $32.5 million, which was paid on April 18, 2018 to shareholders of record as of April 4, 2018.

Partners Equity of The Operatin

Partners Equity of The Operating Partnership	3 Months Ended
	Mar. 31, 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 March 31, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 44,705 $ 44,705 $ 21,271 $ 21,271 Net income attributable to noncontrolling interests (5 ) (5 ) (5 ) (5 ) Preferred unit dividends - - (1,725 ) (1,725 ) Nonforfeitable dividends allocated to unvested restricted unitholders (114 ) (114 ) (99 ) (99 ) Net income attributable to common unitholders $ 44,586 $ 44,586 $ 19,442 $ 19,442 Denominator Weighted-average units outstanding 179,875,324 179,875,324 176,656,763 176,656,763 Contingent securities/Share based compensation - 1,392,786 - 1,024,908 Total weighted-average units outstanding 179,875,324 181,268,110 176,656,763 177,681,671 Earnings per Common Partnership Unit: Net income attributable to common unitholders $ 0.25 $ 0.25 $ 0.11 $ 0.11 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-month periods ended March 31, 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 February 28, 2018, the Operating Partnership declared a distribution of $0.18 per common partnership unit, totaling $32.5 million, which was paid on April 18, 2018 to unitholders of record as of April 4, 2018.

Share Based Compensation

Share Based Compensation	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
SHARE BASED COMPENSATION	12. SHARE BASED COMPENSATION Restricted Share Rights Awards As of March 31, 2018, 632,665 restricted common share rights were outstanding under the Equity Incentive Plan and vest over two to three years from the initial grant dates. The remaining compensation expense to be recognized with respect to these awards at March 31, 2018 was approximately $3.3 million, and is expected to be recognized over a weighted average remaining period of 1.6 years. During the three-month periods ended March 31, 2018 and 2017, the Company recognized compensation expense related to outstanding restricted shares of $1.5 million and $1.5 million, respectively, of which $0.3 million and $0.3 million, respectively, were capitalized as part of the Company’s review of employee salaries eligible for capitalization. The following table summarizes the Company’s restricted share activity during the three months ended March 31, 2018: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2018 455,643 $ 14.95 $ 8,288,146 Granted 178,549 15.66 2,796,077 Vested - - - Forfeited (1,527 ) 15.00 Non-vested at March 31, 2018 632,665 $ 15.15 $ 10,046,720 On February 28, 2018, the Compensation Committee of the Parent Company’s Board of Trustees awarded to officers of the Parent Company an aggregate of 134,487 restricted common share rights (“Restricted Share Rights”), which cliff vest on April 15, 2021. Each Restricted Share Right is scheduled to vest or be settled on April 15, 2021 and, upon completion of vesting each Restricted Share Right will be settled for one common share. The Parent Company pays dividend equivalents on the Restricted Share Rights prior to the vesting or settlement date. Vesting or settlement would accelerate if the recipient of the award were to die, become disabled or retire in a qualifying retirement prior to the vesting or settlement date. Qualifying retirement generally means the recipient’s voluntary termination of employment after reaching at least age 57 and accumulating at least 15 years of service with the Company. In addition, vesting would also accelerate if the Parent Company were to undergo a change of control and, on or before the first anniversary of the change of control, the recipient’s employment were to cease due to a termination without cause or resignation with good reason. In addition, on February 28, 2018, the Compensation Committee awarded non-officer employees an aggregate of 44,062 Restricted Share Rights that vest in three equal annual installments on April 15 of 2019, 2020 and 2021. Vesting of these awards is subject to acceleration upon death, disability or termination without cause within one year following a change of control. In accordance with the accounting standard for share-based compensation, the Company amortizes share-based compensation costs through the qualifying retirement dates for those executives who meet the conditions for qualifying retirement during the scheduled vesting period and whose award agreements provide for vesting upon a qualifying retirement. Restricted Performance Share Units Plan The Compensation Committee of the Parent Company’s Board of Trustees has granted performance share-based awards (referred to as Restricted Performance Share Units, or RPSUs) to officers of the Parent Company. The RPSUs are settled in common shares, with the number of common shares issuable in settlement determined based on the Parent Company’s total shareholder return over specified measurement periods compared to total shareholder returns of comparative groups over the measurement periods. The table below presents certain information as to unvested RPSU awards. RPSU Grant 2/22/2016 3/1/2017 2/28/2018 Total (Amounts below in shares, unless otherwise noted) Non-vested at January 1, 2018 228,077 172,411 - 400,488 Units Granted - - 209,193 209,193 Units Cancelled - - - - Non-vested at March 31, 2018 228,077 172,411 209,193 609,681 Measurement Period Commencement Date 1/1/2016 1/1/2017 1/1/2018 Measurement Period End Date 12/31/2018 12/31/2019 12/31/2020 Units Granted 231,388 174,854 209,193 Fair Value of Units on Grant Date (in thousands) $ 3,558 $ 3,735 $ 4,276 The Company values each RPSU on its grant date using a Monte Carlo simulation. The fair values of each award are being amortized over the three year cliff vesting period. The vesting of RPSUs is subject to acceleration upon a change in control or if the recipient of the award were to die, become disabled or retire in a qualifying retirement prior to the vesting date. In accordance with the accounting standard for share-based compensation, the Company amortizes stock-based compensation costs through the qualifying retirement date for those executives who meet the conditions for qualifying retirement during the schedule vesting period. For the three months ended March 31, 2018, the Company recognized total compensation expense for the 2018, 2017 and 2016 RPSU awards of $2.6 million, of which $0.5 million was capitalized consistent with the Company’s policies for capitalizing eligible portions of employee compensation. For the three months ended March 31, 2017, the Company recognized total compensation expense for the 2017, 2016 and 2015 RPSU awards of $2.4 million, of which $0.5 million was capitalized consistent with the Company’s policies for capitalizing eligible portions of employee compensation. The remaining compensation expense to be recognized at March 31, 2018 was approximately $3.5 million, and is expected to be recognized over a weighted average remaining vesting period of 1.8 years. The Company issued 193,516 common shares on February 1, 2018 in settlement of RPSUs that had been awarded on February 23, 2015 (with a three-year measurement period ended December 31, 2017). Holders of these RPSUs also received a cash dividend of $0.18 per share for these common shares on February 9, 2018.

Segment Information

Segment Information	3 Months Ended
	Mar. 31, 2018
Segment Reporting [Abstract]
SEGMENT INFORMATION	13. SEGMENT INFORMATION As of March 31, 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: March 31, 2018 December 31, 2017 Philadelphia CBD $ 1,653,373 $ 1,643,296 Pennsylvania Suburbs 978,838 958,796 Metropolitan Washington, D.C. 979,041 978,257 Austin, Texas 163,788 163,653 Other 89,666 88,346 $ 3,864,706 $ 3,832,348 Corporate Construction-in-progress $ 129,413 $ 121,188 Land held for development (a) $ 99,436 $ 98,242 (a) 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. The above aforementioned sale was not considered a significant disposition under the accounting guidance for discontinued operations. Net operating income (in thousands): Three-month periods ended March 31, 2018 2017 Total revenue Operating expenses (a) Net operating income (loss) Total revenue Operating expenses (a) Net operating income Philadelphia CBD $ 62,602 $ (24,327 ) $ 38,275 $ 54,449 $ (20,837 ) $ 33,612 Pennsylvania Suburbs 34,882 (12,964 ) 21,918 35,655 (12,584 ) 23,071 Metropolitan Washington, D.C. 23,059 (8,759 ) 14,300 23,362 (9,383 ) 13,979 Austin, Texas 8,364 (3,523 ) 4,841 9,123 (3,573 ) 5,550 Other 6,141 (4,965 ) 1,176 6,362 (3,856 ) 2,506 Corporate 1,310 (1,966 ) (656 ) 1,969 (848 ) 1,121 Operating properties $ 136,358 $ (56,504 ) $ 79,854 $ 130,920 $ (51,081 ) $ 79,839 (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 ventures As of Three-month periods ended March 31, March 31, 2018 December 31, 2017 2018 2017 Philadelphia CBD $ 21,641 $ 39,939 $ (236 ) $ (67 ) Pennsylvania Suburbs - 3,503 - 276 Metropolitan Washington, D.C. 120,041 119,817 (37 ) 467 Austin, Texas 14,069 15,450 80 (1,117 ) MAP Venture (a) 13,713 1,939 (736 ) 58 Other 1,919 13,973 104 (365 ) Total $ 171,383 $ 194,621 $ (825 ) $ (748 ) (a) The MAP Venture represents a joint venture formed between the Company and MAP Ground Lease Holdings LLC, an affiliate of Och-Ziff Capital Management Group, LLC, on February 4, 2016. 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 not calculate NOI in the same manner. NOI is the measure that is used by the Company to evaluate the operating performance of its real estate assets by segment. The Company believes NOI provides useful information to investors regarding 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 impairment 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 income, as defined by GAAP, to consolidated NOI, (in thousands): Three-month periods ended March 31, 2018 2017 Net income $ 44,705 $ 21,271 Plus: Interest expense 19,533 21,437 Interest expense - amortization of deferred financing costs 627 634 Depreciation and amortization 43,291 45,892 General and administrative expenses 8,723 9,325 Equity in loss of Real Estate Ventures 825 748 Provision for impairment - 2,730 Less: Interest income 703 393 Income tax provision (138 ) (100 ) Net gain on disposition of real estate - 7,323 Net gain on sale of undepreciated real estate 22 - Net gain on Real Estate Venture transactions 37,263 14,582 Consolidated net operating income $ 79,854 $ 79,839

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	14. 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 March 31, 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 material 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 have remaining lease terms ranging from 11 to 71 years. Minimum future rental payments on non-cancelable leases at March 31, 2018 are as follows (in thousands): Year Minimum Rent 2018 (nine months remaining) $ 911 2019 1,215 2020 1,215 2021 1,215 2022 1,215 Thereafter 56,477 Total $ 62,248 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. Put Agreement On May 4, 2015, the Company entered into a put agreement in the ordinary course of business that grants an unaffiliated third party the unilateral option to require the Company to purchase a property, at a predetermined price, until May 4, 2018. In addition to the $35.0 million purchase price, the Company would be responsible for transaction and closing costs. There can be no assurance that the counterparty will exercise the option. 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 March 31, 2018, the liability had accreted to $1.8 million. As there were no significant changes to the inputs, the liability remains within Level 3 for fair value reporting. Debt Guarantees As of March 31, 2018, the Company’s unconsolidated real estate ventures had aggregate indebtedness to third parties of $639.3 million. These loans are generally mortgage or construction loans, most of which are non-recourse to the Company. In addition, in certain instances, the Company provides non-recourse carve-out guarantees on these non-recourse loans. As of March 31, 2018, the loans for which there is recourse to the Company consists of the following: (i) a $0.4 million payment guarantee on a loan with a $4.3 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 As of March 31, 2018, pursuant to the Company’s master development agreement for Schuylkill Yards, it committed to acquire a leasehold interest in a land parcel, containing 1.0 acres, located at 3025 JFK Boulevard, in Philadelphia, Pennsylvania, for an estimated gross purchase price of $20.5 million. The leasehold interest will be acquired through a 99-year ground lease. Closing is anticipated to occur during the second quarter of 2018. 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 March 31, 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 first quarter of 2019 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, 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 March 31, 2018, had $3.4 million of future contractual obligations. In addition, the Company estimates $0.9 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. As of March 31, 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 on behalf of each buyer, estimated to cost $13.2 million. Total estimated costs related to the improvements are included in the sale price of each land parcel. Recognition of the sale of the land parcels is deferred until the improvements are completed. As of March 31, 2018, the costs incurred to complete the infrastructure improvements are not in excess of the fixed sale price included in each sale contract. Accordingly, there are no indicators of impairment. 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. The Company currently expects to deliver the building to Subaru during the third quarter of 2018. At March 31, 2018, $16.8 million of the estimated project costs, totaling $46.9 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	3 Months Ended
	Mar. 31, 2018
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	15. SUBSEQUENT EVENTS The Company has evaluated subsequent events through the date the financial statements were issued and determined that there were no material subsequent events.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 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 March 31, 2018, the results of its operations for the three-month periods ended March 31, 2018 and 2017 and its cash flows for the three-month periods ended March 31, 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 three-month period ended March 31, 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-months ended March 31, 2017, the Company included $0.1 million of income tax provision in general and administrative expenses. 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 included herein, the Company reclassified $0.1 million of net income tax provision out of general and administrative expenses into the income tax provision caption 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 provide a definition of restricted cash or restricted cash equivalents. As of March 31, 2018 and March 31, 2017, the Company had $0.8 million and $33.0 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 ending 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 three-months ended March 31, 2017 operating cash flows increased by $0.3 million, which is reflected within the change in other assets caption, and investing cash flows increased by $32.0 million, which relates to Section 1031 proceeds on the sale of Concord Airport Plaza and was presented within the escrowed cash 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 13, “Segment Information,” Three-month period ended March 31, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate Total Base rent $ 39,175 $ 29,894 $ 20,079 $ 4,485 $ 2,196 $ (486 ) $ 95,343 Straight-line rent 4,339 499 208 256 18 (115 ) 5,205 Point of sale 5,341 48 240 122 61 - 5,812 Total rents 48,855 30,441 20,527 4,863 2,275 (601 ) 106,360 Tenant reimbursements 12,366 3,921 928 1,981 765 (112 ) 19,849 Termination fees 47 434 69 - - - 550 Third party management fees, labor reimbursement and leasing 212 8 1,465 1,501 3,095 1,393 7,674 Other income 1,122 78 70 19 6 630 1,925 Total revenue $ 62,602 $ 34,882 $ 23,059 $ 8,364 $ 6,141 $ 1,310 $ 136,358 Rental Revenue The Company owns, operates and manages commercial real estate. Rental revenue is earned by leasing commercial space to its tenants. Rental revenue is recognized on a straight line basis over the term of the leases. The Company’s primary source of revenue are 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 third party vendors and suppliers to fulfill the obligations of operating its properties for its tenants. These goods and services are reimbursed from the Company’s tenants in the period that the expenses are incurred based on the terms of the lease agreements executed 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 (iv) and 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 March 31, 2018, the Company has no outstanding contract assets or contract liabilities.
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 As of March 31, 2018, the Company sold three parcels containing 8.4 acres, 1.7 acres and 6.6 acres to three unaffiliated third parties for $11.8 million, $3.5 million and $14.6 million, respectively. 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 on behalf of each buyer, estimated to cost $13.2 million. Total estimated costs related to the improvements are included in the sale price of each land parcel. Recognition of the sale of the land parcels is deferred until the improvements are completed because the Company has not transferred control of the land parcels to the buyer. The Company expects the infrastructure improvements to be completed and infrastructure guarantee to be relieved by its customers during the second quarter of 2018. At that point in time, the Company will transfer control to the buyer and will be able to determine the total infrastructure costs and recognize the sale of the land. As of March 31, 2018, the total infrastructure costs incurred were $7.6 million, and the Company estimates that it will incur total costs of $13.2 million, which is less than the fixed purchase price for the land parcels. Accordingly, there are no indicators of impairment as of March 31, 2018. 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. 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 Company received cash proceeds of $11.2 million, after closing costs and prorations. 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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements 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 alternatively 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 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: • The Company is in the process of separating lease components due under its leases from non-lease components. Under ASC 842 as a lessor, lease components will be 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 the impact the ASU will have on its consolidated financial statements. • The Company’s tenant reimbursement revenues generated from common area and maintenance services that are provided to its tenants are considered a non-lease component that must be separated, allocated based on the transaction price allocation guidance and accounted for according to the new revenue standard. • 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. • 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. • 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. In January 2018, the FASB issued a proposed amendment to the lease ASU that would 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. If adopted, 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. 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. 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. The amendments in ASU 2018-01 affect the amendments in ASU 2016-02, which are not yet effective but may be early adopted. The effective date and transition requirements for the amendments are the same as the effective date and transition requirements in ASU 2016-02. An entity that early adopted Topic 842 should apply the amendments in this update upon issuance. The Company is in the process of evaluating the impact of this new guidance on its consolidated financial statements.

Organization of the Parent Co28

Organization of the Parent Company and The Operating Partnership (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2018, excludes two development properties and four redevelopment properties under construction or committed for construction (collectively, the “Core Properties”). The Properties were comprised of the following as of March 31, 2018: Number of Properties Rentable Square Feet Office properties 82 15,004,862 Mixed-use properties 5 646,741 Retail properties 1 17,884 Core Properties 88 15,669,487 Development properties 2 247,818 Redevelopment properties 4 583,719 The Properties 94 16,501,024

Basis of Presentation (Tables)

Basis of Presentation (Tables)	3 Months Ended
	Mar. 31, 2018
Accounting Policies [Abstract]
Summary of Revenue Earned by Reportable Segments	The following is a summary of revenue earned by the Company’s reportable segments (see Note 13, “Segment Information,” Three-month period ended March 31, 2018 Philadelphia CBD Pennsylvania Suburbs Metropolitan Washington, D.C. Austin, Texas Other Corporate Total Base rent $ 39,175 $ 29,894 $ 20,079 $ 4,485 $ 2,196 $ (486 ) $ 95,343 Straight-line rent 4,339 499 208 256 18 (115 ) 5,205 Point of sale 5,341 48 240 122 61 - 5,812 Total rents 48,855 30,441 20,527 4,863 2,275 (601 ) 106,360 Tenant reimbursements 12,366 3,921 928 1,981 765 (112 ) 19,849 Termination fees 47 434 69 - - - 550 Third party management fees, labor reimbursement and leasing 212 8 1,465 1,501 3,095 1,393 7,674 Other income 1,122 78 70 19 6 630 1,925 Total revenue $ 62,602 $ 34,882 $ 23,059 $ 8,364 $ 6,141 $ 1,310 $ 136,358

Real Estate Investments (Tables

Real Estate Investments (Tables)	3 Months Ended
	Mar. 31, 2018
Real Estate [Abstract]
Gross Carrying Value Of Properties	As of March 31, 2018 and December 31, 2017, the gross carrying value of the properties was as follows (in thousands): March 31, December 31, 2018 2017 Land $ 498,197 $ 492,197 Building and improvements 2,915,399 2,896,113 Tenant improvements 451,110 444,038 Total $ 3,864,706 $ 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)
Dispositions	The Company sold the following land parcels during the three-month period ended March 31, 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 $ - (a) January 10, 2018 Westpark Land Durham, NC 1 13.1 485 412 22 Total Dispositions 2 19.7 $ 15,056 $ 14,921 $ 22 (a) The Company has a continuing involvement, through a completion guarantee, which requires the Company as developer to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The Company does not transfer control of the land parcel until the infrastructure improvements are complete and the guarantee is released. Accordingly, the cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets and the Company will recognize the sale once the infrastructure improvements are complete. See Note 14, “Commitments and Contingencies,” for further discussion of the infrastructure improvements.

Investment in Unconsolidated 31

Investment in Unconsolidated Real Estate Ventures (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) (a) Other Total Net property $ 263,384 $ 159,159 $ - $ 488,224 $ 910,767 Other assets 35,080 24,520 - 84,092 143,692 Other liabilities 17,189 4,844 - 72,129 94,162 Debt, net 247,844 92,813 - 294,662 635,319 Equity (b) 33,431 86,022 - 205,525 324,978 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, evo at Cira 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-month periods ended March 31, 2018 and 2017 (in thousands): Three-month period ended March 31, 2018 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 14,356 $ 5,836 $ 995 $ 21,634 $ 42,821 Operating expenses (6,066 ) (2,544 ) (250 ) (11,908 ) (20,768 ) Interest expense, net (2,294 ) (864 ) (388 ) (4,580 ) (8,126 ) Depreciation and amortization (5,698 ) (2,137 ) (376 ) (6,173 ) (14,384 ) Loss on early extinguishment of debt - - (718 ) - (718 ) Net income (loss) $ 298 $ 291 $ (737 ) $ (1,027 ) $ (1,175 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ 149 $ 146 $ (369 ) $ (632 ) $ (706 ) Basis adjustments and other (69 ) 15 11 (76 ) (119 ) Equity in income (loss) of Real Estate Ventures $ 80 $ 161 $ (358 ) $ (708 ) $ (825 ) Three-month period ended March 31, 2017 DRA (G&I) Austin Brandywine-AI Venture LLC HSRE-BDN I, LLC (evo at Cira Centre South) Other Total Revenue $ 21,552 $ 7,325 $ 3,154 $ 22,248 $ 54,279 Operating expenses (9,313 ) (2,940 ) (679 ) (12,234 ) (25,166 ) Interest expense, net (3,689 ) (1,145 ) (898 ) (5,098 ) (10,830 ) Depreciation and amortization (9,229 ) (2,809 ) (1,128 ) (7,595 ) (20,761 ) Net income (loss) $ (679 ) $ 431 $ 449 $ (2,679 ) $ (2,478 ) Ownership interest % 50 % 50 % 50 % (a) (a) Company's share of net income (loss) $ (340 ) $ 216 $ 225 $ (1,262 ) $ (1,161 ) Basis adjustments and other (25 ) 310 7 121 413 Equity in income (loss) of Real Estate Ventures $ (365 ) $ 526 $ 232 $ (1,141 ) $ (748 ) (a) The Company’s unconsolidated ownership interests ranged from 25% to 70% during the three-month periods ended March 31, 2018 and 20% to 70% during the three-month period ended March 31, 2017, subject to specified priority allocations of distributable cash in certain of the Real Estate Ventures.

Intangible Assets and Liabili32

Intangible Assets and Liabilities (Tables)	3 Months Ended
	Mar. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets and Liabilities	As of March 31, 2018 and December 31, 2017, the Company’s intangible assets/liabilities were comprised of the following (in thousands): March 31, 2018 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 106,574 $ (46,495 ) $ 60,079 Tenant relationship value 10,593 (9,064 ) 1,529 Above market leases acquired 4,712 (2,706 ) 2,006 Total intangible assets, net $ 121,879 $ (58,265 ) $ 63,614 Acquired lease intangibles, net: Below market leases acquired $ 35,719 $ (16,209 ) $ 19,510 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 March 31, 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 (nine months remaining) $ 11,483 $ 2,648 2019 13,130 2,847 2020 10,452 2,081 2021 7,538 1,432 2022 5,355 1,264 Thereafter 15,656 9,238 Total $ 63,614 $ 19,510

Debt Obligations (Tables)

Debt Obligations (Tables)	3 Months Ended
	Mar. 31, 2018
Debt Disclosure [Abstract]
Consolidated debt obligations	The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at March 31, 2018 and December 31, 2017 (in thousands): March 31, 2018 December 31, 2017 Effective Interest Rate Maturity Date MORTGAGE DEBT: Two Logan Square $ 84,037 $ 84,440 3.98% May 2020 Four Tower Bridge 9,695 - 4.50% (a) Feb 2021 One Commerce Square 122,808 123,667 3.64% Apr 2023 Two Commerce Square 112,000 112,000 4.51% Apr 2023 Principal balance outstanding 328,540 320,107 Plus: fair market value premium (discount), net (2,041 ) (2,325 ) Less: deferred financing costs (525 ) (566 ) Mortgage indebtedness $ 325,974 $ 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 (4,341 ) (4,423 ) Less: deferred financing costs (10,211 ) (10,575 ) Total unsecured indebtedness $ 1,614,058 $ 1,613,612 Total Debt Obligations $ 1,940,032 $ 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 March 31, 2018, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2018 (nine months remaining) $ 5,508 2019 7,595 2020 87,226 2021 15,143 2022 256,332 Thereafter 1,585,346 Total principal payments 1,957,150 Net unamortized premiums/(discounts) (6,382 ) Net deferred financing costs (10,736 ) Outstanding indebtedness $ 1,940,032

Fair Value of Financial Instr34

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 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): March 31, 2018 December 31, 2017 Carrying Amount (a) Fair Value Carrying Amount (a) Fair Value Unsecured notes payable $ 1,286,936 $ 1,284,180 $ 1,286,573 $ 1,314,900 Variable rate debt $ 327,122 $ 309,577 $ 327,039 $ 308,872 Mortgage notes payable $ 325,974 $ 312,402 $ 317,216 $ 304,665 Note receivable $ 3,490 $ 3,565 $ 3,532 $ 3,605 (a) In April 2015, the FASB issued guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of the corresponding debt liability, consistent with debt discounts. As a result, the carrying amounts presented in the table above are net of deferred financing costs of $8.7 million and $8.9 million for unsecured notes payable, $1.5 million and $1.6 million for variable rate debt and $0.5 million and $0.6 million for mortgage notes payable as of March 31, 2018 and December 31, 2017, respectively.

Fair Value of Derivative Fina35

Fair Value of Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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 3/31/2018 12/31/2017 3/31/2018 12/31/2017 Assets Swap Interest Rate Cash Flow (a) $ 250,000 $ 250,000 3.718 % October 8, 2015 October 8, 2022 $ 9,763 $ 5,694 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 360 25 Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 242 59 $ 301,548 $ 301,548 (a) Hedging unsecured variable rate debt.

Beneficiaries Equity of the P36

Beneficiaries Equity of the Parent Company (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 44,705 $ 44,705 $ 21,271 $ 21,271 Net income attributable to noncontrolling interests (376 ) (376 ) (169 ) (169 ) Nonforfeitable dividends allocated to unvested restricted shareholders (114 ) (114 ) (99 ) (99 ) Preferred share dividends - - (1,725 ) (1,725 ) Net income attributable to common shareholders $ 44,215 $ 44,215 $ 19,278 $ 19,278 Denominator Weighted-average shares outstanding 178,395,525 178,395,525 175,176,964 175,176,964 Contingent securities/Share based compensation - 1,392,786 - 1,024,908 Weighted-average shares outstanding 178,395,525 179,788,311 175,176,964 176,201,872 Earnings per Common Share: Net income attributable to common shareholders $ 0.25 $ 0.25 $ 0.11 $ 0.11

Partners Equity of the Operat37

Partners Equity of the Operating Partnership (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 44,705 $ 44,705 $ 21,271 $ 21,271 Net income attributable to noncontrolling interests (376 ) (376 ) (169 ) (169 ) Nonforfeitable dividends allocated to unvested restricted shareholders (114 ) (114 ) (99 ) (99 ) Preferred share dividends - - (1,725 ) (1,725 ) Net income attributable to common shareholders $ 44,215 $ 44,215 $ 19,278 $ 19,278 Denominator Weighted-average shares outstanding 178,395,525 178,395,525 175,176,964 175,176,964 Contingent securities/Share based compensation - 1,392,786 - 1,024,908 Weighted-average shares outstanding 178,395,525 179,788,311 175,176,964 176,201,872 Earnings per Common Share: Net income attributable to common shareholders $ 0.25 $ 0.25 $ 0.11 $ 0.11
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 March 31, 2018 2017 Basic Diluted Basic Diluted Numerator Net income $ 44,705 $ 44,705 $ 21,271 $ 21,271 Net income attributable to noncontrolling interests (5 ) (5 ) (5 ) (5 ) Preferred unit dividends - - (1,725 ) (1,725 ) Nonforfeitable dividends allocated to unvested restricted unitholders (114 ) (114 ) (99 ) (99 ) Net income attributable to common unitholders $ 44,586 $ 44,586 $ 19,442 $ 19,442 Denominator Weighted-average units outstanding 179,875,324 179,875,324 176,656,763 176,656,763 Contingent securities/Share based compensation - 1,392,786 - 1,024,908 Total weighted-average units outstanding 179,875,324 181,268,110 176,656,763 177,681,671 Earnings per Common Partnership Unit: Net income attributable to common unitholders $ 0.25 $ 0.25 $ 0.11 $ 0.11

Share Based Compensation (Table

Share Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2018
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Company's Restricted Share Activity	The following table summarizes the Company’s restricted share activity during the three months ended March 31, 2018: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2018 455,643 $ 14.95 $ 8,288,146 Granted 178,549 15.66 2,796,077 Vested - - - Forfeited (1,527 ) 15.00 Non-vested at March 31, 2018 632,665 $ 15.15 $ 10,046,720
Schedule of Restricted Performance Share Units Plan	The table below presents certain information as to unvested RPSU awards. RPSU Grant 2/22/2016 3/1/2017 2/28/2018 Total (Amounts below in shares, unless otherwise noted) Non-vested at January 1, 2018 228,077 172,411 - 400,488 Units Granted - - 209,193 209,193 Units Cancelled - - - - Non-vested at March 31, 2018 228,077 172,411 209,193 609,681 Measurement Period Commencement Date 1/1/2016 1/1/2017 1/1/2018 Measurement Period End Date 12/31/2018 12/31/2019 12/31/2020 Units Granted 231,388 174,854 209,193 Fair Value of Units on Grant Date (in thousands) $ 3,558 $ 3,735 $ 4,276

Segment Information (Tables)

Segment Information (Tables)	3 Months Ended
	Mar. 31, 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: March 31, 2018 December 31, 2017 Philadelphia CBD $ 1,653,373 $ 1,643,296 Pennsylvania Suburbs 978,838 958,796 Metropolitan Washington, D.C. 979,041 978,257 Austin, Texas 163,788 163,653 Other 89,666 88,346 $ 3,864,706 $ 3,832,348 Corporate Construction-in-progress $ 129,413 $ 121,188 Land held for development (a) $ 99,436 $ 98,242 (a) 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. The above aforementioned sale was not considered a significant disposition under the accounting guidance for discontinued operations. Net operating income (in thousands): Three-month periods ended March 31, 2018 2017 Total revenue Operating expenses (a) Net operating income (loss) Total revenue Operating expenses (a) Net operating income Philadelphia CBD $ 62,602 $ (24,327 ) $ 38,275 $ 54,449 $ (20,837 ) $ 33,612 Pennsylvania Suburbs 34,882 (12,964 ) 21,918 35,655 (12,584 ) 23,071 Metropolitan Washington, D.C. 23,059 (8,759 ) 14,300 23,362 (9,383 ) 13,979 Austin, Texas 8,364 (3,523 ) 4,841 9,123 (3,573 ) 5,550 Other 6,141 (4,965 ) 1,176 6,362 (3,856 ) 2,506 Corporate 1,310 (1,966 ) (656 ) 1,969 (848 ) 1,121 Operating properties $ 136,358 $ (56,504 ) $ 79,854 $ 130,920 $ (51,081 ) $ 79,839 (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 ventures As of Three-month periods ended March 31, March 31, 2018 December 31, 2017 2018 2017 Philadelphia CBD $ 21,641 $ 39,939 $ (236 ) $ (67 ) Pennsylvania Suburbs - 3,503 - 276 Metropolitan Washington, D.C. 120,041 119,817 (37 ) 467 Austin, Texas 14,069 15,450 80 (1,117 ) MAP Venture (a) 13,713 1,939 (736 ) 58 Other 1,919 13,973 104 (365 ) Total $ 171,383 $ 194,621 $ (825 ) $ (748 ) (a) The MAP Venture represents a joint venture formed between the Company and MAP Ground Lease Holdings LLC, an affiliate of Och-Ziff Capital Management Group, LLC, on February 4, 2016. 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 income, as defined by GAAP, to consolidated NOI, (in thousands): Three-month periods ended March 31, 2018 2017 Net income $ 44,705 $ 21,271 Plus: Interest expense 19,533 21,437 Interest expense - amortization of deferred financing costs 627 634 Depreciation and amortization 43,291 45,892 General and administrative expenses 8,723 9,325 Equity in loss of Real Estate Ventures 825 748 Provision for impairment - 2,730 Less: Interest income 703 393 Income tax provision (138 ) (100 ) Net gain on disposition of real estate - 7,323 Net gain on sale of undepreciated real estate 22 - Net gain on Real Estate Venture transactions 37,263 14,582 Consolidated net operating income $ 79,854 $ 79,839

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Minimum Future Rental Payments on Non-cancelable Leases	Minimum future rental payments on non-cancelable leases at March 31, 2018 are as follows (in thousands): Year Minimum Rent 2018 (nine months remaining) $ 911 2019 1,215 2020 1,215 2021 1,215 2022 1,215 Thereafter 56,477 Total $ 62,248

Organization of The Parent Co41

Organization of The Parent Company and The Operating Partnership (Textual) (Details)	Mar. 31, 2018ft²aproperty
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties | property	94
Net Rentable Square Feet	16,501,024
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	4
Parent Company [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the Operating Partnership	99.20%
Net Rentable Square Feet	8,800,000
Undeveloped Parcels of Land | a	200
Area of Additional Undeveloped Parcels of Land With Option to Purchase | a	59
Total Potential Development Capacity	14,700,000
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 Co42

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)	Mar. 31, 2018ft²property
Real Estate Properties [Line Items]
Number of Properties | property	94
Rentable Square Feet | ft²	16,501,024
Office Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	82
Rentable Square Feet | ft²	15,004,862
Mixed-use Properties [Member]
Real Estate Properties [Line Items]
Number of Properties | property	5
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	88
Rentable Square Feet | ft²	15,669,487
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	4
Rentable Square Feet | ft²	583,719

Basis of Presentation (Textual)

Basis of Presentation (Textual) (Details)	Mar. 15, 2017USD ($)ft²	Mar. 31, 2018USD ($)aParcel	Dec. 31, 2017USD ($)	Mar. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Apr. 28, 2017USD ($)a	Jan. 30, 2017USD ($)a
Basis Of Presentation [Line Items]
Income tax provision		$ 138,000		$ 100,000
Increase in operating cash flows		12,911,000		10,626,000
Lease agreement variable income		0
Contract assets outstanding		0
Contract liabilities outstanding		0
Proceeds from the sale of properties		14,921,000		74,159,000
Assets held for sale, net		0	$ 392,000
Gain (Loss) on Sale		$ 0		7,323,000
Garza Land Sale [Member]
Basis Of Presentation [Line Items]
Number of Parcels | Parcel		3
Infrastructure improvements to land, estimated cost		$ 13,200,000
Total infrastructure costs incurred		$ 7,600,000
Garza Land Sale [Member] | Parcel One [Member]
Basis Of Presentation [Line Items]
Area of land sold | a						8.4
Sales Price						$ 11,800,000
Garza Land Sale [Member] | Parcel Two [Member]
Basis Of Presentation [Line Items]
Area of land sold | a							1.7
Sales Price							$ 3,500,000
Garza Land Sale [Member] | Parcel Three [Member]
Basis Of Presentation [Line Items]
Area of land sold | a		6.6
Sales Price		$ 14,600,000
Philadelphia Marine Center (Marine Piers) [Member]
Basis Of Presentation [Line Items]
Sales Price	$ 21,400,000
Rentable Square Feet | ft²	181,900
Payment by cash on purchases	$ 12,000,000
Balance payment on purchases	$ 9,400,000
Date of second installment payment	Jan. 31, 2020
Proceeds from the sale of properties	$ 11,200,000
Assets held for sale, net	4,700,000
Gain (Loss) on Sale	6,500,000
Deferred gain on sale	$ 9,400,000
ASU 2016-18 [Member]
Basis Of Presentation [Line Items]
Restricted cash		$ 800,000		33,000,000
Increase in operating cash flows				300,000
Increase in investing cash flows				32,000,000
General and Administrative Expenses [Member]
Basis Of Presentation [Line Items]
Income tax provision				100,000
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			$ 100,000	$ 100,000
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
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	$ 95,343
Straight-line rent	5,205
Point of sale	5,812
Total rents	106,360	$ 103,332
Tenant reimbursements	19,849	18,535
Termination fees	550	1,673
Third party management fees, labor reimbursement and leasing	7,674	6,485
Other	1,925	895
Total revenue	136,358	130,920
Philadelphia CBD [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	39,175
Straight-line rent	4,339
Point of sale	5,341
Total rents	48,855
Tenant reimbursements	12,366
Termination fees	47
Third party management fees, labor reimbursement and leasing	212
Other	1,122
Total revenue	62,602
Pennsylvania Suburbs [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	29,894
Straight-line rent	499
Point of sale	48
Total rents	30,441
Tenant reimbursements	3,921
Termination fees	434
Third party management fees, labor reimbursement and leasing	8
Other	78
Total revenue	34,882
Metropolitan Washington, D.C. [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	20,079
Straight-line rent	208
Point of sale	240
Total rents	20,527
Tenant reimbursements	928
Termination fees	69
Third party management fees, labor reimbursement and leasing	1,465
Other	70
Total revenue	23,059
Austin, Texas [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	4,485
Straight-line rent	256
Point of sale	122
Total rents	4,863
Tenant reimbursements	1,981
Third party management fees, labor reimbursement and leasing	1,501
Other	19
Total revenue	8,364
Other [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	2,196
Straight-line rent	18
Point of sale	61
Total rents	2,275
Tenant reimbursements	765
Third party management fees, labor reimbursement and leasing	3,095
Other	6
Total revenue	6,141
Corporate [Member]
Segment Reporting Revenue Reconciling Item [Line Items]
Base rent	(486)
Straight-line rent	(115)
Total rents	(601)
Tenant reimbursements	(112)
Third party management fees, labor reimbursement and leasing	1,393
Other	630
Total revenue	$ 1,310	$ 1,969

Real Estate Investments - Gross

Real Estate Investments - Gross Carrying Value of Properties (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment, Gross [Abstract]
Land	$ 498,197	$ 492,197
Tenant improvements	451,110	444,038
Operating properties	3,864,706	3,832,348
Total	3,864,706	3,832,348
Building and Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Operating properties	$ 2,915,399	$ 2,896,113

Real Estate Investments - Acqui

Real Estate Investments - Acquisitions (Textual) (Details) $ in Thousands	Mar. 22, 2018USD ($)a	Mar. 31, 2018USD ($)ft²	Mar. 31, 2018USD ($)ft²	Mar. 31, 2017USD ($)	Jan. 05, 2018USD ($)ft²
Business Acquisition [Line Items]
Capitalized transaction costs		$ 3,120		$ 4,129
Area of real estate property | ft²		16,501,024	16,501,024
Revenue		$ 136,358		130,920
Net income		$ 44,329		$ 21,102
Seven Tower Bridge [Member]
Business Acquisition [Line Items]
Sale of ownership interest percentage					20.00%
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 ground lease rent	$ 24,600
Capitalized transaction costs	$ 300
Four Tower Bridge [Member]
Business Acquisition [Line Items]
Ownership percentage					35.00%
Capitalized transaction costs					$ 100
Fair value of unencumbered acquisition related costs, to tangible and intangible assets and liabilities					$ 23,696
Revenue			$ 700
Net income			$ 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

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 - Pur48

Real Estate Investments - Purchase Price Allocation (Parenthetical) (Details) - USD ($) $ in Thousands	Jan. 05, 2018	Mar. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Outstanding principal balance on mortgage debt assumed		$ 325,974	$ 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 Land Parcels Sold (Details) $ in Thousands		3 Months Ended
		Mar. 31, 2018USD ($)aParcel	Mar. 31, 2017USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties		$ 14,921	$ 74,159
Gain on Sale		$ 22	$ 0
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		2
Acreage of land | a		19.7
Sales Price		$ 15,056
Proceeds from the sale of properties		14,921
Gain on Sale		$ 22
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]	$ 0
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]	The Company has a continuing involvement, through a completion guarantee, which requires the Company as developer to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The Company does not transfer control of the land parcel until the infrastructure improvements are complete and the guarantee is released. Accordingly, the cash received at settlement was recorded as “Deferred income, gains and rent” on the Company’s consolidated balance sheets and the Company will recognize the sale once the infrastructure improvements are complete. See Note 14, “Commitments and Contingencies,” for further discussion of the infrastructure improvements.

Investment in Unconsolidated 50

Investment in Unconsolidated Real Estate Ventures (Textual) (Details)	Jan. 10, 2018USD ($)property	Jan. 05, 2018USD ($)ft²	Mar. 31, 2018USD ($)ft²aReal_Estate_InvestmentApartment_unit	Mar. 31, 2017USD ($)	Dec. 31, 2017USD ($)
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method			$ 171,383,000		$ 194,621,000
Management fees			7,674,000	$ 6,485,000
Accounts receivable			$ 17,794,000		17,938,000
Area of real estate property | ft²			16,501,024
Net gain on Real Estate Venture transactions			$ 37,263,000	14,582,000
Proceeds from real estate venture sales			$ 42,953,000	27,230,000
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
Office Properties [Member]
Schedule Of Equity Method Investments [Line Items]
Area of real estate property | ft²			15,004,862
Real Estate Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Management fees			$ 1,300,000	1,500,000
Accounts receivable			1,400,000		$ 900,000
Real Estate Venture [Member] | Lease Commission Income [Member]
Schedule Of Equity Method Investments [Line Items]
Management fees			$ 800,000	$ 1,300,000
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Investment			10
Investment in Real Estate Ventures, equity method			$ 171,400,000
Real estate ventures aggregate indebtedness to third parties			$ 639,300,000
Unconsolidated Real Estate Ventures [Member] | Minimum [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage			25.00%	20.00%
Unconsolidated Real Estate Ventures [Member] | Maximum [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage			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
Rentable Square Feet | ft²			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
Acreage of land | a			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
Acreage of land | a			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
Number of Property units | Apartment_unit			321
Four Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment 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			$ 4,300,000
Guarantees, maximum exposure amount			400,000
4040 Wilson Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Guarantees, maximum exposure amount			41,300,000
Loan total borrowing capacity			$ 150,000,000

Investment in Unconsolidated 51

Investment in Unconsolidated Real Estate Ventures - Summary of Financial Position of Real Estate Ventures (Details) - USD ($) $ in Thousands		Mar. 31, 2018		Dec. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Net property		$ 910,767		$ 1,083,965
Other assets		143,692		161,932
Other liabilities		94,162		97,707
Debt, net		635,319		766,420
Equity	[1]	324,978		381,770
DRA Austin Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		263,384		263,557
Other assets		35,080		42,272
Other liabilities		17,189		24,131
Debt, net		247,844		248,700
Equity	[1]	33,431		32,998
BDN - Al Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		159,159		158,960
Other assets		24,520		24,181
Other liabilities		4,844		4,493
Debt, net		92,813		92,917
Equity	[1]	86,022		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 [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		488,224		517,458
Other assets		84,092		86,916
Other liabilities		72,129		67,435
Debt, net		294,662		314,667
Equity	[1]	$ 205,525		$ 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, evo at Cira sold the 345-unit student housing tower, its sole operating asset. See ‘evo at Cira Disposition’ section below.

Investment in Unconsolidated 52

Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Schedule Of Equity Method Investments [Line Items]
Equity in income (loss) of Real Estate Ventures	$ (825)	$ (748)
DRA Austin Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	14,356	21,552
Operating expenses	(6,066)	(9,313)
Interest expense, net	(2,294)	(3,689)
Depreciation and amortization	(5,698)	(9,229)
Net income (loss)	$ 298	$ (679)
Ownership interest %	50.00%	50.00%
Company's share of net income (loss)	$ 149	$ (340)
Basis adjustments and other	(69)	(25)
Equity in income (loss) of Real Estate Ventures	80	(365)
Brandywine - AI Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	5,836	7,325
Operating expenses	(2,544)	(2,940)
Interest expense, net	(864)	(1,145)
Depreciation and amortization	(2,137)	(2,809)
Net income (loss)	$ 291	$ 431
Ownership interest %	50.00%	50.00%
Company's share of net income (loss)	$ 146	$ 216
Basis adjustments and other	15	310
Equity in income (loss) of Real Estate Ventures	161	526
HSRE-BDN I, LLC (evo at Cira Centre South) [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	995	3,154
Operating expenses	(250)	(679)
Interest expense, net	(388)	(898)
Depreciation and amortization	(376)	(1,128)
Loss on early extinguishment of debt	(718)
Net income (loss)	$ (737)	$ 449
Ownership interest %	50.00%	50.00%
Company's share of net income (loss)	$ (369)	$ 225
Basis adjustments and other	11	7
Equity in income (loss) of Real Estate Ventures	(358)	232
Other [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	21,634	22,248
Operating expenses	(11,908)	(12,234)
Interest expense, net	(4,580)	(5,098)
Depreciation and amortization	(6,173)	(7,595)
Net income (loss)	(1,027)	(2,679)
Company's share of net income (loss)	(632)	(1,262)
Basis adjustments and other	(76)	121
Equity in income (loss) of Real Estate Ventures	(708)	(1,141)
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	42,821	54,279
Operating expenses	(20,768)	(25,166)
Interest expense, net	(8,126)	(10,830)
Depreciation and amortization	(14,384)	(20,761)
Loss on early extinguishment of debt	(718)
Net income (loss)	(1,175)	(2,478)
Company's share of net income (loss)	(706)	(1,161)
Basis adjustments and other	(119)	413
Equity in income (loss) of Real Estate Ventures	$ (825)	$ (748)

Investment in Unconsolidated 53

Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Parenthetical) (Details) - Unconsolidated Real Estate Ventures [Member]	Mar. 31, 2018	Mar. 31, 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 Liabili54

Intangible Assets and Liabilities - Intangible Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Intangible Assets [Line Items]
Intangible Assets, Total Cost	$ 121,879	$ 123,806
Intangible Assets, Accumulated Amortization	(58,265)	(58,834)
Intangible Assets, net	63,614	64,972
Acquired Lease Intangibles, Net	19,510	20,274
Below market leases [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross	35,719	36,213
Acquired Lease Intangibles, Accumulated Amortization	(16,209)	(15,939)
Acquired Lease Intangibles, Net	19,510	20,274
In-place lease value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	106,574	108,060
Intangible Assets, Accumulated Amortization	(46,495)	(47,003)
Intangible Assets, net	60,079	61,057
Tenant relationship value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	10,593	11,201
Intangible Assets, Accumulated Amortization	(9,064)	(9,275)
Intangible Assets, net	1,529	1,926
Above market leases acquired [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	4,712	4,545
Intangible Assets, Accumulated Amortization	(2,706)	(2,556)
Intangible Assets, net	$ 2,006	$ 1,989

Intangible Assets and Liabili55

Intangible Assets and Liabilities - Annual Amortization of Intangible Assets, Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets
2018 (nine months remaining)	$ 11,483
2,019	13,130
2,020	10,452
2,021	7,538
2,022	5,355
Thereafter	15,656
Intangible Assets, net	63,614	$ 64,972
Liabilities
2018 (nine months remaining)	2,648
2,019	2,847
2,020	2,081
2,021	1,432
2,022	1,264
Thereafter	9,238
Acquired Lease Intangibles, Net	$ 19,510	$ 20,274

Debt Obligations - Consolidated

Debt Obligations - Consolidated Debt Obligations Outstanding (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Dec. 31, 2017
Consolidated debt obligations
Plus: premiums/(discounts), net		$ (6,382)
Less: deferred financing costs		(10,736)
Total Debt Obligations		1,940,032	$ 1,930,828
Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		328,540	320,107
Plus: premiums/(discounts), net		(2,041)	(2,325)
Less: deferred financing costs		(525)	(566)
Total mortgage indebtedness		325,974	317,216
Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		1,628,610	1,628,610
Plus: premiums/(discounts), net		(4,341)	(4,423)
Less: deferred financing costs		(10,211)	(10,575)
Total unsecured indebtedness		1,614,058	1,613,612
Two Logan Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 84,037	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		$ 9,695
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		$ 122,808	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		$ 112,000	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) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Revolving Credit Facility [Member] | New Credit Facility [Member]
Debt Instrument [Line Items]
Debt term	4 years
Maximum borrowing capacity	$ 600,000,000
Variable interest rate	1.20%
Debt instrument, description of variable rate basis	LIBOR plus 1.20%.
Proceeds from line of credit	$ 0	$ 0
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	Mar. 31, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
2018 (nine months remaining)	$ 5,508
2,019	7,595
2,020	87,226
2,021	15,143
2,022	256,332
Thereafter	1,585,346
Total principal payments	1,957,150
Net unamortized premiums/(discounts)	(6,382)
Net deferred financing costs	(10,736)
Total Debt Obligations	$ 1,940,032	$ 1,930,828

Fair Value of Financial Instr59

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Details) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage notes payable, net		$ 325,974	$ 317,216
Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable	[1]	3,490	3,532
Carrying Amount [Member] | Unsecured Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Unsecured notes payable	[1]	1,286,936	1,286,573
Carrying Amount [Member] | Variable Rate Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate debt	[1]	327,122	327,039
Carrying Amount [Member] | Mortgages Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage notes payable, net	[1]	325,974	317,216
Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable, fair value		3,565	3,605
Fair Value [Member] | Unsecured Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		1,284,180	1,314,900
Fair Value [Member] | Variable Rate Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		309,577	308,872
Fair Value [Member] | Mortgages Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		$ 312,402	$ 304,665
[1]	In April 2015, the FASB issued guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct reduction from the carrying amount of the corresponding debt liability, consistent with debt discounts. As a result, the carrying amounts presented in the table above are net of deferred financing costs of $8.7 million and $8.9 million for unsecured notes payable, $1.5 million and $1.6 million for variable rate debt and $0.5 million and $0.6 million for mortgage notes payable as of March 31, 2018 and December 31, 2017, respectively.

Fair Value of Financial Instr60

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Parenthetical) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	$ 10,736
Unsecured Notes Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	10,211	$ 10,575
Unsecured Notes Payable [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	8,700	8,900
Variable Rate Debt [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	1,500	1,600
Mortgages Notes Payable [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Deferred financing costs, net	$ 500	$ 600

Limited Partners' Non-Control61

Limited Partners' Non-Controlling Interests in the Parent Company (Textual) (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Noncontrolling Interest [Abstract]
Aggregate amount related to non-controlling interests classified within equity	$ 15.4	$ 15.2
Settlement value of non controlling interest in operating partnership	$ 23.5	$ 26.9

Fair Value of Derivative Fina62

Fair Value of Derivative Financial Instruments - Terms and Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 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	$ 9,763	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	$ 360	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	$ 242	$ 59

Beneficiaries Equity of the P63

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
	Mar. 31, 2018	Mar. 31, 2017
Numerator
Net income	$ 44,705	$ 21,271
Net income attributable to noncontrolling interests, Basic	(376)	(169)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(114)	(99)
Distribution to preferred shareholders	0	(1,725)
Net income attributable to Common Shareholders of Brandywine Realty Trust	44,215	19,278
Net income attributable to noncontrolling interests, Diluted	(376)	(169)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(114)	(99)
Net income attributable to common shareholders, Diluted	$ 44,215	$ 19,278
Denominator
Basic weighted average shares outstanding (in shares)	178,395,525	175,176,964
Contingent securities/Share based compensation (in shares)	1,392,786	1,024,908
Diluted weighted average shares outstanding (in shares)	179,788,311	176,201,872
Earnings per Common Share:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.25	$ 0.11
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.25	$ 0.11

Beneficiaries Equity of the P64

Beneficiaries Equity of the Parent Company (Textual) (Details) - USD ($) $ / shares in Units, $ in Millions	Feb. 28, 2018	Mar. 31, 2018	Mar. 31, 2017
Class of Stock [Line Items]
Dividends, Common Stock	$ 32.5
Dividends payable, date to be paid	Apr. 18, 2018
Dividends payable, date of record	Apr. 4, 2018
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 Operat65

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
	Mar. 31, 2018	Mar. 31, 2017
Numerator
Net income	$ 44,705	$ 21,271
Distribution to preferred shareholders	0	(1,725)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(114)	(99)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	$ (114)	$ (99)
Denominator
Basic weighted average shares outstanding (in shares)	178,395,525	175,176,964
Contingent securities/Share based compensation (in shares)	1,392,786	1,024,908
Diluted weighted average shares outstanding (in shares)	179,788,311	176,201,872
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.25	$ 0.11
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.25	$ 0.11
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Net income	$ 44,705	$ 21,271
Net income attributable to noncontrolling interests	(5)	(5)
Distribution to preferred shareholders	0	(1,725)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic	(114)	(99)
Net income attributable to common unitholders, Basic	44,586	19,442
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted	(114)	(99)
Net income attributable to common unitholders, Diluted	$ 44,586	$ 19,442
Denominator
Basic weighted average shares outstanding (in shares)	179,875,324	176,656,763
Contingent securities/Share based compensation (in shares)	1,392,786	1,024,908
Diluted weighted average shares outstanding (in shares)	181,268,110	177,681,671
Earnings per Common Partnership Unit:
Net income attributable to common shareholders, Basic (USD per share)	$ 0.25	$ 0.11
Net income attributable to common shareholders, Diluted (USD per share)	$ 0.25	$ 0.11

Partners Equity of the Operat66

Partners Equity of the Operating Partnership (Textual) (Details) $ / shares in Units, $ in Millions	Feb. 28, 2018USD ($)$ / shares
Earnings Per Common Partnership Unit [Line Items]
Dividends, Common Stock | $	$ 32.5
Dividends payable, date to be paid	Apr. 18, 2018
Dividends payable, date of record	Apr. 4, 2018
Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share | $ / shares	$ 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	Apr. 18, 2018
Dividends payable, date of record	Apr. 4, 2018
BRANDYWINE OPERATING PARTNERSHIP, L.P. | Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share | $ / shares	$ 0.18

Share Based Compensation (Textu

Share Based Compensation (Textual) (Details) $ / shares in Units, $ in Millions	Feb. 28, 2018Installmentshares	Feb. 01, 2018shares	Mar. 31, 2018USD ($)shares	Mar. 31, 2017USD ($)	Feb. 09, 2018$ / shares	Dec. 31, 2017shares
Restricted Share Rights Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number			632,665			455,643
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			two to three years from the initial grant dates
Unrecognized compensation expenses | $			$ 3.3
Weighted average period over which options will be recognized			1 year 7 months 6 days
Share-based compensation expense, capitalized | $			$ 0.3	$ 0.3
Share-based compensation expense | $			$ 1.5	1.5
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			178,549
Voluntary Termination Of Employment Terms			after reaching at least age 57 and accumulating at least 15 years of service with the Company
Accumulated Service Period For Voluntary Termination			15 years
Restricted Share Rights Awards [Member] | Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Voluntary Termination of Employment Age Limit			57 years
Restricted Share Rights Awards [Member] | Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	44,062
Number of restricted share right will get settled for common share	1
Number of Vesting Installments | Installment	3
Restricted Share Rights Awards [Member] | Cliff Vest [Member] | Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	134,487
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2021
Restricted Share Rights Awards [Member] | Installment One [Member] | Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2019
Restricted Share Rights Awards [Member] | Installment Two [Member] | Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2020
Restricted Share Rights Awards [Member] | Installment Three [Member] | Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2021
Restricted Share Rights Awards [Member] | Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			2 years
Restricted Share Rights Awards [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years
Restricted Performance Share Units Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			three-year
Unrecognized compensation expenses | $			$ 3.5
Weighted average period over which options will be recognized			1 year 9 months 18 days
Share-based compensation expense, capitalized | $			$ 0.5	0.5
Share-based compensation expense | $			$ 2.6	$ 2.4
Common shares issued for share based compensation		193,516
Dividends Payable, Amount Per Share | $ / shares					$ 0.18
Restricted Performance Share Units Plan [Member] | Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number			609,681			400,488
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			209,193
Restricted Performance Share Units Plan [Member] | Cliff Vest [Member] | Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights			three year cliff vesting period

Share Based Compensation - Rest

Share Based Compensation - Restricted Share Activity (Details) - Restricted Share Rights Awards [Member]	3 Months Ended
	Mar. 31, 2018USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2018, shares | shares	455,643
Granted, shares | shares	178,549
Vested, shares | shares	0
Forfeited, shares | shares	(1,527)
Non-vested at March 31, 2018, shares | shares	632,665
Non-vested at January 1, 2018, Weighted Average Grant Date Fair Value | $ / shares	$ 14.95
Granted, Weighted Average Grant Date Fair Value | $ / shares	15.66
Vested, Weighted Average Grant Date Fair Value | $ / shares	0
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	15
Non-vested at March 31, 2018, Weighted Average Grant Date Fair Value | $ / shares	$ 15.15
Non-vested at January 1, 2018, Aggregate Intrinsic Value | $	$ 8,288,146
Granted, Aggregate Intrinsic Value | $	2,796,077
Vested, Aggregate Intrinsic Value | $	0
Non-vested at March 31, 2018, Aggregate Intrinsic Value | $	$ 10,046,720

Share Based Compensation - Re69

Share Based Compensation - Restricted Performance Share Units (Details) - Restricted Performance Share Units Plan [Member] - Executive Officer [Member] - USD ($) $ in Thousands	Feb. 28, 2018	Mar. 01, 2017	Feb. 22, 2016	Mar. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2018, shares				400,488
Granted, shares				209,193
Units Cancelled				0
Non-vested at March 31, 2018, shares				609,681
Units Granted	209,193	174,854	231,388
Fair Value of Units on Grant Date (in thousands)	$ 4,276	$ 3,735	$ 3,558
February 22, 2016 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2018, shares				228,077
Granted, shares				0
Units Cancelled				0
Non-vested at March 31, 2018, shares				228,077
Measurement Period Commencement Date				Jan. 1, 2016
Measurement Period End Date				Dec. 31, 2018
March 01, 2017 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2018, shares				172,411
Granted, shares				0
Units Cancelled				0
Non-vested at March 31, 2018, shares				172,411
Measurement Period Commencement Date				Jan. 1, 2017
Measurement Period End Date				Dec. 31, 2019
February 28, 2018 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2018, shares				0
Granted, shares				209,193
Units Cancelled				0
Non-vested at March 31, 2018, shares				209,193
Measurement Period Commencement Date				Jan. 1, 2018
Measurement Period End Date				Dec. 31, 2020

Segment Information (Textual) (

Segment Information (Textual) (Details)	3 Months Ended
	Mar. 31, 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		Mar. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Operating properties		$ 3,864,706	$ 3,832,348
Construction-in-progress		129,413	121,188
Land held for development	[1]	99,436	98,242
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Operating properties		1,653,373	1,643,296
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Operating properties		978,838	958,796
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Operating properties		979,041	978,257
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Operating properties		163,788	163,653
Other [Member]
Segment Reporting Information [Line Items]
Operating properties		$ 89,666	$ 88,346
[1]	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.

Segment Information - Real Es72

Segment Information - Real Estate Investments, at Cost of Company's Reportable Segments (Parenthetical) (Details)	Dec. 31, 2017a
Other [Member] | Assets Held-for-sale [Member] | Land Held For Development [Member]
Segment Reporting Information [Line Items]
Acreage of land	13.1

Segment Information - Net Opera

Segment Information - Net Operating Income of Company's Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Total revenue		$ 136,358	$ 130,920
Operating expenses	[1]	(56,504)	(51,081)
Net operating income (loss)		79,854	79,839
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Total revenue		62,602
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Total revenue		34,882
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Total revenue		23,059
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Total revenue		8,364
Other [Member]
Segment Reporting Information [Line Items]
Total revenue		6,141
Operating Segments [Member] | Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Total revenue		62,602	54,449
Operating expenses	[1]	(24,327)	(20,837)
Net operating income (loss)		38,275	33,612
Operating Segments [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Total revenue		34,882	35,655
Operating expenses	[1]	(12,964)	(12,584)
Net operating income (loss)		21,918	23,071
Operating Segments [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Total revenue		23,059	23,362
Operating expenses	[1]	(8,759)	(9,383)
Net operating income (loss)		14,300	13,979
Operating Segments [Member] | Austin, Texas [Member]
Segment Reporting Information [Line Items]
Total revenue		8,364	9,123
Operating expenses	[1]	(3,523)	(3,573)
Net operating income (loss)		4,841	5,550
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Total revenue		6,141	6,362
Operating expenses	[1]	(4,965)	(3,856)
Net operating income (loss)		1,176	2,506
Corporate [Member]
Segment Reporting Information [Line Items]
Total revenue		1,310	1,969
Operating expenses	[1]	(1,966)	(848)
Net operating income (loss)		$ (656)	$ 1,121
[1]	Includes property operating expenses, real estate taxes and third party management expense.

Segment Information - Unconsoli

Segment Information - Unconsolidated Real Estate Ventures of Company's Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		$ 171,383		$ 194,621
Equity in income (loss) of real estate ventures		(825)	$ (748)
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		21,641		39,939
Equity in income (loss) of real estate ventures		(236)	(67)
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		0		3,503
Equity in income (loss) of real estate ventures		0	276
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		120,041		119,817
Equity in income (loss) of real estate ventures		(37)	467
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		14,069		15,450
Equity in income (loss) of real estate ventures		80	(1,117)
MAP Venture [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity	[1]	13,713		1,939
Equity in income (loss) of real estate ventures	[1]	(736)	58
Other [Member]
Segment Reporting Information [Line Items]
Investment in real estate ventures, at equity		1,919		$ 13,973
Equity in income (loss) of real estate ventures		$ 104	$ (365)
[1]	The MAP Venture represents a joint venture formed between the Company and MAP Ground Lease Holdings LLC, an affiliate of Och-Ziff Capital Management Group, LLC, on February 4, 2016. 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
	Mar. 31, 2018	Mar. 31, 2017
Segment Reporting [Abstract]
Net income	$ 44,705	$ 21,271
Plus:
Interest expense	19,533	21,437
Interest expense - amortization of deferred financing costs	627	634
Depreciation and amortization	43,291	45,892
General and administrative expenses	8,723	9,325
Equity in loss of Real Estate Ventures	825	748
Provision for impairment	0	2,730
Less:
Interest income	703	393
Income tax provision	(138)	(100)
Net gain on disposition of real estate	0	7,323
Net gain on sale of undepreciated real estate	22	0
Net gain on Real Estate Venture transactions	37,263	14,582
Consolidated net operating income	$ 79,854	$ 79,839

Commitments and Contingencies76

Commitments and Contingencies (Textual) (Details)	Dec. 03, 2015ft²	Apr. 02, 2015USD ($)	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)aParcel	Mar. 16, 2018a	Oct. 13, 2017USD ($)	Apr. 28, 2017a	Jan. 30, 2017a	Jul. 01, 2016a
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
Estimated project costs				$ 46,900,000
Subaru Build-to-Service Center Project [Member] | Other Assets [Member]
Property Subject to or Available for Operating Lease [Line Items]
Project costs funded				16,800,000
Unconsolidated Real Estate Ventures [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness to third parties				639,300,000
PJP VII [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount				400,000
Real estate property debt				4,300,000
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		$ 1,800,000
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]
Estimated of funding In the ground lease						$ 37,300,000
One Drexel Plaza [Member] | Scenario Forecast [Member]
Property Subject to or Available for Operating Lease [Line Items]
Estimated aggregate cost			$ 83,100,000
Acquisition cost, inclusive in estimated aggregate cost			$ 37,800,000
3025 JFK Boulevard [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms				99 years
Acreage of land | a				1
Estimated gross purchase price				$ 20,500,000
Drexel Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Required spending in capital improvements to property				3,400,000
Estimated potential additional contribution obligation				$ 900,000
Garza Land Acquisition [Member]
Property Subject to or Available for Operating Lease [Line Items]
Acreage of land | a									34.6
Number of Parcels | Parcel				3
Infrastructure improvements to land, estimated cost				$ 13,200,000
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
Put Agreement [Member]
Property Subject to or Available for Operating Lease [Line Items]
Purchase price				$ 35,000,000
Minimum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms				11 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				71 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	Mar. 31, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2018 (nine months remaining)	$ 911
2,019	1,215
2,020	1,215
2,021	1,215
2,022	1,215
Thereafter	56,477
Total	$ 62,248