Brandywine Operating Partnership 10-K 1 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 17, 2017	Jun. 30, 2016
Entity Registrant Name	BRANDYWINE REALTY TRUST
Entity Central Index Key	790,816
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 2,908,952,336
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		175,186,624
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Registrant Name	BRANDYWINE OPERATING PARTNERSHIP, L.P.
Entity Central Index Key	1,060,386
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Amendment Flag	false
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Real estate investments:
Operating properties	$ 3,586,295	$ 3,693,000
Accumulated depreciation	(852,476)	(867,035)
Operating real estate investments, net	2,733,819	2,825,965
Construction-in-progress	297,462	268,983
Land held for development	150,970	130,479
Total real estate investments, net	3,182,251	3,225,427
Assets held for sale, net	41,718	584,365
Cash and cash equivalents	193,919	56,694
Accounts receivable, net of allowance of $2,373 and $1,736 in 2016 and 2015, respectively	12,446	17,126
Accrued rent receivable, net of allowance of $13,743 and $14,442 in 2016 and 2015, respectively	149,624	145,092
Investment in Real Estate Ventures, equity method	281,331	241,004
Deferred costs, net	91,342	101,419
Intangible assets, net	72,478	111,623
Other assets	74,104	71,761
Total assets	4,099,213	4,554,511
LIABILITIES AND EQUITY
Mortgage notes payable, net	321,549	545,753
Unsecured term loans, net	248,099	247,800
Unsecured senior notes, net	1,443,464	1,591,164
Accounts payable and accrued expenses	103,404	99,856
Distributions payable	30,032	28,249
Deferred income, gains and rent	31,620	30,413
Acquired lease intangibles, net	18,119	25,655
Liabilities related to assets held for sale	81	2,151
Other liabilities	19,408	31,379
Total liabilities	2,215,776	2,602,420
Commitments and contingencies
Equity:
6.90% Series E Preferred Shares, $0.01 par value; issued and outstanding- 4,000,000 in 2016 and 2015	40	40
Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 400,000,000; 175,140,760 and 174,688,568 issued and outstanding in 2016 and 2015, respectively	1,752	1,747
Additional paid-in-capital	3,258,870	3,252,622
Deferred compensation payable in common shares	13,684	11,918
Common shares in grantor trust, 899,457 in 2016, 745,686 in 2015	(13,684)	(11,918)
Cumulative earnings	539,319	499,086
Accumulated other comprehensive loss	(1,745)	(5,192)
Cumulative distributions	(1,931,892)	(1,814,378)
Total Brandywine Realty Trust's equity	1,866,344	1,933,925
Non-controlling interests	17,093	18,166
Total beneficiaries' equity	1,883,437	1,952,091
Total liabilities and beneficiaries' equity	4,099,213	4,554,511
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Operating properties	3,586,295	3,693,000
Accumulated depreciation	(852,476)	(867,035)
Operating real estate investments, net	2,733,819	2,825,965
Construction-in-progress	297,462	268,983
Land held for development	150,970	130,479
Total real estate investments, net	3,182,251	3,225,427
Assets held for sale, net	41,718	584,365
Cash and cash equivalents	193,919	56,694
Accounts receivable, net of allowance of $2,373 and $1,736 in 2016 and 2015, respectively	12,446	17,126
Accrued rent receivable, net of allowance of $13,743 and $14,442 in 2016 and 2015, respectively	149,624	145,092
Investment in Real Estate Ventures, equity method	281,331	241,004
Deferred costs, net	91,342	101,419
Intangible assets, net	72,478	111,623
Other assets	74,104	71,761
Total assets	4,099,213	4,554,511
LIABILITIES AND EQUITY
Mortgage notes payable, net	321,549	545,753
Unsecured term loans, net	248,099	247,800
Unsecured senior notes, net	1,443,464	1,591,164
Accounts payable and accrued expenses	103,404	99,856
Distributions payable	30,032	28,249
Deferred income, gains and rent	31,620	30,413
Acquired lease intangibles, net	18,119	25,655
Liabilities related to assets held for sale	81	2,151
Other liabilities	19,408	31,379
Total liabilities	2,215,776	2,602,420
Commitments and contingencies
Redeemable limited partnership units at redemption value; 1,479,799 and 1,535,102 issued and outstanding in 2016 and 2015, respectively	23,795	22,114
Equity:
6.90% Series E Preferred Shares, $0.01 par value; issued and outstanding- 4,000,000 in 2016 and 2015	96,850	96,850
General Partnership Capital 175,140,760 and 174,688,568 units issued and outstanding in 2016 and 2015, respectively	1,762,764	1,836,692
Accumulated other comprehensive loss	(2,122)	(5,597)
Total Brandywine Operating Partnership, L.P.'s equity	1,857,492	1,927,945
Non-controlling interest - consolidated real estate ventures	2,150	2,032
Total partners' equity	1,859,642	1,929,977
Total liabilities and beneficiaries' equity	$ 4,099,213	$ 4,554,511

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts receivable, allowance	$ 2,373	$ 1,736
Accrued rent receivable, allowance	$ 13,743	$ 14,442
Preferred Stock, Shares Authorized	20,000,000	20,000,000
Preferred Stock, Dividend Rate, Percentage	6.90%	6.90%
Preferred Stock, Par or Stated Value Per Share (USD per share)	$ 0.01	$ 0.01
Preferred Stock, Shares Issued	4,000,000	4,000,000
Preferred Stock, Shares Outstanding	4,000,000	4,000,000
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	175,140,760	174,688,568
Common Stock, Shares, Outstanding	175,140,760	174,688,568
Common Shares in Grantor Trust	899,457	745,686
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Accounts receivable, allowance	$ 2,373	$ 1,736
Accrued rent receivable, allowance	$ 13,743	$ 14,442
Preferred Stock, Dividend Rate, Percentage	6.90%	6.90%
Preferred Stock, Shares Issued	4,000,000	4,000,000
Preferred Stock, Shares Outstanding	4,000,000	4,000,000
Redeemable Limited Partnership Units Issued	1,479,799	1,535,102
Redeemable Limited Partnership Units Outstanding	1,479,799	1,535,102
General Partners' Capital Account, Units Issued	175,140,760	174,688,568
General Partners' Capital Account, Units Outstanding	175,140,760	174,688,568

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Rents	$ 421,505	$ 486,731	$ 483,682
Tenant reimbursements	70,629	85,722	84,879
Termination fees	2,339	4,797	8,000
Third party management fees, labor reimbursement and leasing	26,674	18,764	17,200
Other	4,316	6,617	3,221
Total revenue	525,463	602,631	596,982
Operating expenses:
Property operating expenses	152,926	181,170	177,330
Real estate taxes	46,252	50,623	51,844
Third party management expenses	10,270	6,294	6,791
Depreciation and amortization	189,676	219,029	208,569
General and administrative expenses	26,596	29,406	26,779
Provision for impairment	40,517	82,208	1,765
Total operating expenses	466,237	568,730	473,078
Operating income	59,226	33,901	123,904
Other income (expense):
Interest income	1,236	1,224	3,974
Tax credit transaction income	0	19,955	11,853
Interest expense	(84,708)	(110,717)	(124,329)
Interest expense - amortization of deferred financing costs	(2,696)	(4,557)	(5,148)
Interest expense - financing obligation	(679)	(1,237)	(1,144)
Recognized hedge activity	0	0	(828)
Equity in loss of Real Estate Ventures	(11,503)	(811)	(790)
Net gain on disposition of real estate	116,983	20,496	4,901
Net gain on sale of undepreciated real estate	9,232	3,019	1,184
Net gain from remeasurement of investments in real estate ventures	0	758	458
Net gain (loss) on real estate venture transactions	20,000	7,229	(417)
Loss on early extinguishment of debt	(66,590)	0	(7,594)
Income (loss) from continuing operations	40,501	(30,740)	6,024
Discontinued operations:
Income from discontinued operations	0	0	18
Net gain on disposition of discontinued operations	0	0	900
Total discontinued operations	0	0	918
Net income (loss)	40,501	(30,740)	6,942
Net (income) loss attributable to non-controlling interests	(310)	339	33
Net (income) loss from continuing operations attributable to non-controlling interests - consolidated real estate ventures	(310)	339	43
Net income (loss) attributable to Brandywine Realty Trust	40,191	(30,401)	6,975
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Nonforfeitable dividends allocated to unvested restricted shareholders	(341)	(329)	(349)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ 32,950	$ (37,630)	$ (274)
Basic income (loss) per Common Share:
Continuing operations (USD per share)	$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations (USD per share)	0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	0.19	(0.21)	0
Diluted income (loss) per Common Share:
Continuing operations (USD per share)	0.19	(0.21)	(0.01)
Discontinued operations (USD per share)	0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ 0.19	$ (0.21)	$ 0
Basic weighted average shares outstanding (in shares)	175,018,163	178,162,160	166,202,649
Diluted weighted average shares outstanding (in shares)	176,010,814	178,162,160	166,202,649
Net income (loss) attributable to Brandywine Realty Trust
Total continuing operations	$ 40,191	$ (30,401)	$ 6,067
Total discontinued operations	0	0	908
Net income (loss) attributable to Brandywine Realty Trust	40,191	(30,401)	6,975
Net income (loss)	$ 40,501	$ (30,740)	$ 6,942
Distributions declared per Common Share (USD per share)	$ 0.63	$ 0.60	$ 0.60
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Rents	$ 421,505	$ 486,731	$ 483,682
Tenant reimbursements	70,629	85,722	84,879
Termination fees	2,339	4,797	8,000
Third party management fees, labor reimbursement and leasing	26,674	18,764	17,200
Other	4,316	6,617	3,221
Total revenue	525,463	602,631	596,982
Operating expenses:
Property operating expenses	152,926	181,170	177,330
Real estate taxes	46,252	50,623	51,844
Third party management expenses	10,270	6,294	6,791
Depreciation and amortization	189,676	219,029	208,569
General and administrative expenses	26,596	29,406	26,779
Provision for impairment	40,517	82,208	1,765
Total operating expenses	466,237	568,730	473,078
Operating income	59,226	33,901	123,904
Other income (expense):
Interest income	1,236	1,224	3,974
Tax credit transaction income	0	19,955	11,853
Interest expense	(84,708)	(110,717)	(124,329)
Interest expense - amortization of deferred financing costs	(2,696)	(4,557)	(5,148)
Interest expense - financing obligation	(679)	(1,237)	(1,144)
Recognized hedge activity	0	0	(828)
Equity in loss of Real Estate Ventures	(11,503)	(811)	(790)
Net gain on disposition of real estate	116,983	20,496	4,901
Net gain on sale of undepreciated real estate	9,232	3,019	1,184
Net gain from remeasurement of investments in real estate ventures	0	758	458
Net gain (loss) on real estate venture transactions	20,000	7,229	(417)
Loss on early extinguishment of debt	(66,590)	0	(7,594)
Income (loss) from continuing operations	40,501	(30,740)	6,024
Discontinued operations:
Income from discontinued operations	0	0	18
Net gain on disposition of discontinued operations	0	0	900
Total discontinued operations	0	0	918
Net income (loss)	40,501	(30,740)	6,942
Net (income) loss from continuing operations attributable to non-controlling interests - consolidated real estate ventures	(15)	3	44
Net income (loss) attributable to Brandywine Realty Trust	40,486	(30,737)	6,986
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Nonforfeitable dividends allocated to unvested restricted shareholders	(341)	(329)	(349)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ 33,245	$ (37,966)	$ (263)
Basic income (loss) per Common Share:
Continuing operations (USD per share)	$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations (USD per share)	0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	0.19	(0.21)	0
Diluted income (loss) per Common Share:
Continuing operations (USD per share)	0.19	(0.21)	(0.01)
Discontinued operations (USD per share)	0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ 0.19	$ (0.21)	$ 0
Basic weighted average shares outstanding (in shares)	176,523,800	179,697,262	167,942,246
Diluted weighted average shares outstanding (in shares)	177,516,451	179,697,262	167,942,246
Net income (loss) attributable to Brandywine Realty Trust
Total continuing operations	$ 40,501	$ (30,740)	$ 6,024
Total discontinued operations	0	0	918
Net income (loss) attributable to Brandywine Realty Trust	40,486	(30,737)	6,986
Net income (loss)	$ 40,501	$ (30,740)	$ 6,942
Distributions declared per Common Share (USD per share)	$ 0.63	$ 0.60	$ 0.60

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income (loss)		$ 40,501	$ (30,740)	$ 6,942
Comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments		2,371	(1,010)	(1,190)
Loss on settlement of interest rate swaps		0	0	(828)
Reclassification of realized losses on derivative financial instruments to operations, net	[1]	1,104	420	388
Total comprehensive income (loss)		3,475	(590)	(1,630)
Comprehensive income (loss)		43,976	(31,330)	5,312
Comprehensive income (loss) attributable to non-controlling interest		(338)	344	51
Comprehensive income (loss) attributable to reporting entity		43,638	(30,986)	5,363
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Net income (loss)		40,501	(30,740)	6,942
Comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments		2,371	(1,010)	(1,190)
Loss on settlement of interest rate swaps		0	0	(828)
Reclassification of realized losses on derivative financial instruments to operations, net	[2]	1,104	420	388
Total comprehensive income (loss)		3,475	(590)	(1,630)
Comprehensive income (loss)		43,976	(31,330)	5,312
Comprehensive income (loss) attributable to non-controlling interest		(15)	3	44
Comprehensive income (loss) attributable to reporting entity		$ 43,961	$ (31,327)	$ 5,356
[1]	Amounts reclassified from comprehensive income to interest expense within the Consolidated Statements of Operations.
[2]	Amounts reclassified from comprehensive income to interest expense within the Consolidated Statement 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 Loss [Member]	Cumulative Distributions [Member]	Noncontrolling Interest [Member]
Beginning Balance, Shares at Dec. 31, 2013		4,000,000	156,731,993	312,279
Beginning Balance at Dec. 31, 2013	$ 1,921,435	$ 40	$ 1,566	$ 5,407	$ 2,971,596	$ (5,407)	$ 522,528	$ (2,995)	$ (1,592,515)	$ 21,215
Net income (loss)	6,942						6,975			(33)
Other comprehensive income (loss)	(1,630)							(1,612)		(18)
Issuance of Common Shares of Beneficial Interest, Shares			21,850,000
Issuance of Common Shares of Beneficial Interest	335,398		$ 219		335,179
Equity issuance costs	(495)				(495)
Conversion of LP Units to Common Shares, Shares			228,536
Conversion of LP Units to Common Shares			$ 2		3,612					(3,614)
Share-based compensation activity, Shares			403,902
Share-based compensation activity	6,847		$ 6		6,857		(16)
Share Issuance from/(to) Deferred Compensation Plan, Shares			80,152	72,257
Share issuance from/(to) Deferred Compensation Plan	(90)			$ 812	(90)	(812)
Share Choice Plan Issuance, Shares			(1,423)
Adjustment to Non-controlling Interest					(1,966)					1,966
Preferred Share distributions	(6,900)								(6,900)
Distributions declared	(102,181)								(101,164)	(1,017)
Ending Balance, Shares at Dec. 31, 2014		4,000,000	179,293,160	384,536
Ending Balance at Dec. 31, 2014	2,159,326	$ 40	$ 1,793	$ 6,219	3,314,693	(6,219)	529,487	(4,607)	(1,700,579)	18,499
Net income (loss)	(30,740)						(30,401)			(339)
Other comprehensive income (loss)	$ (590)							(585)		(5)
Repurchase and retirement of Common Shares of Beneficial Interest, Shares	(5,209,437)		(5,209,437)
Repurchase and retirement of Common Shares of Beneficial Interest	$ (67,325)		$ (52)		(67,273)
Issuance of partnership interest in joint venture	1,025									1,025
Bonus share issuance, Shares			8,447
Bonus share issuance	125				125
Equity issuance costs	(105)				(105)
Share-based compensation activity, Shares			509,675	280,011
Share-based compensation activity	5,097		$ 6		5,091
Share Issuance from/(to) Deferred Compensation Plan, Shares			88,146	81,139
Share issuance from/(to) Deferred Compensation Plan	(2)			$ 5,699	(2)	(5,699)
Share Choice Plan Issuance, Shares			(1,423)
Adjustment to Non-controlling Interest					93					(93)
Preferred Share distributions	(6,900)								(6,900)
Distributions declared	(107,820)								(106,899)	(921)
Ending Balance, Shares at Dec. 31, 2015		4,000,000	174,688,568	745,686
Ending Balance at Dec. 31, 2015	1,952,091	$ 40	$ 1,747	$ 11,918	3,252,622	(11,918)	499,086	(5,192)	(1,814,378)	18,166
Net income (loss)	40,501						40,191			310
Other comprehensive income (loss)	$ 3,475							3,447		28
Repurchase and retirement of Common Shares of Beneficial Interest, Shares	0
Issuance of partnership interest in consolidated real estate venture	$ 108									108
Conversion of LP Units to Common Shares, Shares			55,303
Conversion of LP Units to Common Shares			$ 1		874					(875)
Share-based compensation activity, Shares			405,200
Share-based compensation activity	5,764		$ 4		5,718		42
Share Issuance from/(to) Deferred Compensation Plan, Shares			(8,311)	153,771
Share issuance from/(to) Deferred Compensation Plan	(47)			$ 1,766	(47)	(1,766)
Adjustment to Non-controlling Interest					(297)					297
Preferred Share distributions	(6,900)								(6,900)
Distributions declared	(111,555)								(110,614)	(941)
Ending Balance, Shares at Dec. 31, 2016		4,000,000	175,140,760	899,457
Ending 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

Consolidated Statements of Ben7

Consolidated Statements of Beneficiaries' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Distributions declared per Common Share (USD per share)	$ 0.63	$ 0.60	$ 0.60
Cumulative Distributions [Member]
Distributions declared per Common Share (USD per share)	0.63	0.60	0.60
Noncontrolling Interest [Member]
Distributions declared per Common Share (USD per share)	$ 0.63	$ 0.60	$ 0.60

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Cash flows from operating activities:
Net income (loss)	$ 40,501	$ (30,740)	$ 6,942
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	189,676	219,029	208,569
Amortization of deferred financing costs	2,696	4,557	5,148
Amortization of debt discount/(premium), net	1,471	(755)	(531)
Amortization of stock compensation costs	4,310	5,065	4,137
Shares used for employee taxes upon vesting of share awards	(879)	(2,055)	(1,177)
Recognized hedge activity	0	0	828
Settlement of hedge transaction	0	(5,266)	0
Straight-line rent income	(28,351)	(23,668)	(16,046)
Amortization of acquired above (below) market leases, net	(6,529)	(7,960)	(6,377)
Straight-line ground rent expense	88	88	89
Provision for doubtful accounts	1,865	2,489	1,763
Net (gain) loss on real estate venture transactions	(20,000)	(7,418)	417
Net gain on sale of interests in real estate	(126,215)	(23,515)	(6,085)
Preacquisition cost write-off	0	1,299	0
Net gain from remeasurement of investment in real estate ventures	0	(758)	(458)
Loss on early extinguishment of debt	66,590	0	7,594
Provision for impairment	40,517	82,208	1,765
Tax credit transaction income	0	(19,955)	(11,853)
Real Estate Venture loss in excess of distributions	12,125	2,034	1,954
Deferred financing obligation	(679)	(1,237)	(1,147)
Changes in assets and liabilities:
Accounts receivable	2,373	(848)	(2,869)
Other assets	(155)	837	(4,111)
Accounts payable and accrued expenses	(8,004)	4,083	962
Deferred income, gains and rent	137	(521)	2,436
Other liabilities	685	(1,894)	(2,951)
Net cash provided by operating activities	172,222	195,099	188,999
Cash flows from investing activities:
Acquisition of properties	(20,406)	(150,472)	(18,443)
Acquisition of property - 1031 exchange funds applied	0	(62,812)	0
Proceeds from the sale of properties	784,331	247,228	118,855
Sale of property - 1031 exchange funds held in escrow	0	62,800	0
Net proceeds from the contribution of properties to an unconsolidated real estate venture	0	50,158	0
Net proceeds from the contribution of land to an unconsolidated real estate venture	0	0	8,212
Distribution of sale proceeds from a real estate venture	21,022	6,100	0
Issuance of mortgage note receivable	(3,380)	0	0
Loan provided to an unconsolidated real estate venture	0	0	(88,000)
Proceeds from repayment of mortgage notes receivable	0	88,000	7,026
Capital expenditures for tenant improvements	(51,398)	(97,851)	(131,077)
Capital expenditures for redevelopments	(11,909)	(48,367)	(19,245)
Capital expenditures for developments	(191,184)	(179,927)	(86,608)
Advances for the purchase of tenant assets, net of repayments	(784)	308	(540)
Investment in unconsolidated Real Estate Ventures	(28,610)	(68,549)	(46,098)
Deposits for real estate	(746)	(878)	0
Escrowed cash	6,992	516	283
Cash distribution from unconsolidated Real Estate Ventures in excess of cumulative equity income	13,065	8,557	9,767
Leasing costs paid	(16,083)	(21,263)	(24,917)
Net cash provided by (used in) investing activities	500,910	(166,452)	(270,785)
Cash flows from financing activities:
Proceeds from mortgage notes payable	86,900	130,000	0
Repayments of mortgage notes payable	(357,151)	(222,836)	(13,441)
Proceeds from unsecured term loan borrowing	0	50,000	0
Repayments of unsecured term loan	0	0	(250,828)
Proceeds from credit facility borrowings	195,000	89,000	0
Repayments of credit facility borrowings	(195,000)	(89,000)	0
Net proceeds from unsecured notes	0	0	496,459
Net proceeds from issuance of common shares\units	0	0	335,016
Repayments of unsecured notes	(149,919)	0	(383,768)
Debt financing costs paid	(495)	(5,202)	(3,705)
Proceeds from the exercise of stock options	1,286	127	2,143
Partner contributions to consolidated real estate venture	108	1,025	0
Repurchase and retirement of common shares	0	(67,320)	0
Distributions paid to shareholders	(115,702)	(114,328)	(104,731)
Distributions to non-controlling interest	(934)	(921)	(1,064)
Net cash provided by (used in) financing activities	(535,907)	(229,455)	76,081
Increase (Decrease) in cash and cash equivalents	137,225	(200,808)	(5,705)
Cash and cash equivalents at beginning of year	56,694	257,502	263,207
Cash and cash equivalents at end of period	193,919	56,694	257,502
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2016, 2015 and 2014 of $12,835, $12,150 and $6,802, respectively	97,843	124,953	129,160
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	30,032	28,249	28,871
Change in investment in real estate ventures as a result of dispositions	2,023	0	0
Change in investment in real estate ventures related to non-cash disposition of property	(25,165)	(25,127)	(5,897)
Change in operating real estate related to non-cash property disposition	0	25,127	0
Change in real estate investments related to non-cash property acquisition	0	(66,324)	0
Change in investments in joint venture related to non-cash acquisition of property	0	66,324	0
Change in investments in joint venture related to contribution of land	0	0	(1,182)
Change in receivable from settlement of acquisitions	0	0	619
Change in other liabilities from contingent consideration related to a business combination	0	1,585	0
Change in operating real estate from contingent consideration related to a business combination	0	(1,585)	0
Change in other liabilities from a deferred payment related to an asset acquisition	0	2,000	0
Change in operating real estate from a deferred payment related to an asset acquisition	0	(2,000)	0
Change in operating real estate from deconsolidation of 3141 Fairview Park Drive	44,313	0	0
Change in investment in real estate ventures from deconsolidation of 3141 Fairview Park Drive	(12,642)	0	0
Change in mortgage notes payable from deconsolidation of 3141 Fairview Park Drive	(20,582)	0	0
Change in other liabilities from deconsolidation of 3141 Fairview Park Drive	(12,384)	0	0
Change in capital expenditures financed through accounts payable at period end	8,222	(7,654)	7,336
Change in capital expenditures financed through retention payable at period end	848	6,104	6,164
Change in unfunded tenant allowance	0	(273)	(955)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income (loss)	40,501	(30,740)	6,942
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	189,676	219,029	208,569
Amortization of deferred financing costs	2,696	4,557	5,148
Amortization of debt discount/(premium), net	1,471	(755)	(531)
Amortization of stock compensation costs	4,310	5,065	4,137
Shares used for employee taxes upon vesting of share awards	(879)	(2,055)	(1,177)
Recognized hedge activity	0	0	828
Settlement of hedge transaction	0	(5,266)	0
Straight-line rent income	(28,351)	(23,668)	(16,046)
Amortization of acquired above (below) market leases, net	(6,529)	(7,960)	(6,377)
Straight-line ground rent expense	88	88	89
Provision for doubtful accounts	1,865	2,489	1,763
Net (gain) loss on real estate venture transactions	(20,000)	(7,418)	417
Net gain on sale of interests in real estate	(126,215)	(23,515)	(6,085)
Preacquisition cost write-off	0	1,299	0
Net gain from remeasurement of investment in real estate ventures	0	(758)	(458)
Loss on early extinguishment of debt	66,590	0	7,594
Provision for impairment	40,517	82,208	1,765
Tax credit transaction income	0	(19,955)	(11,853)
Real Estate Venture loss in excess of distributions	12,125	2,034	1,954
Deferred financing obligation	(679)	(1,237)	(1,147)
Changes in assets and liabilities:
Accounts receivable	2,373	(848)	(2,869)
Other assets	(155)	837	(4,111)
Accounts payable and accrued expenses	(8,004)	4,083	962
Deferred income, gains and rent	137	(521)	2,436
Other liabilities	685	(1,894)	(2,951)
Net cash provided by operating activities	172,222	195,099	188,999
Cash flows from investing activities:
Acquisition of properties	(20,406)	(150,472)	(18,443)
Acquisition of property - 1031 exchange funds applied	0	(62,812)	0
Proceeds from the sale of properties	784,331	247,228	118,855
Sale of property - 1031 exchange funds held in escrow	0	62,800	0
Net proceeds from the contribution of properties to an unconsolidated real estate venture	0	50,158	0
Net proceeds from the contribution of land to an unconsolidated real estate venture	0	0	8,212
Distribution of sale proceeds from a real estate venture	21,022	6,100	0
Issuance of mortgage note receivable	(3,380)	0	0
Loan provided to an unconsolidated real estate venture	0	0	(88,000)
Proceeds from repayment of mortgage notes receivable	0	88,000	7,026
Capital expenditures for tenant improvements	(51,398)	(97,851)	(131,077)
Capital expenditures for redevelopments	(11,909)	(48,367)	(19,245)
Capital expenditures for developments	(191,184)	(179,927)	(86,608)
Advances for the purchase of tenant assets, net of repayments	(784)	308	(540)
Investment in unconsolidated Real Estate Ventures	(28,610)	(68,549)	(46,098)
Deposits for real estate	(746)	(878)	0
Escrowed cash	6,992	516	283
Cash distribution from unconsolidated Real Estate Ventures in excess of cumulative equity income	13,065	8,557	9,767
Leasing costs paid	(16,083)	(21,263)	(24,917)
Net cash provided by (used in) investing activities	500,910	(166,452)	(270,785)
Cash flows from financing activities:
Proceeds from mortgage notes payable	86,900	130,000	0
Repayments of mortgage notes payable	(357,151)	(222,836)	(13,441)
Proceeds from unsecured term loan borrowing	0	50,000	0
Repayments of unsecured term loan	0	0	(250,828)
Proceeds from credit facility borrowings	195,000	89,000	0
Repayments of credit facility borrowings	(195,000)	(89,000)	0
Net proceeds from unsecured notes	0	0	496,459
Net proceeds from issuance of common shares\units	0	0	335,016
Repayments of unsecured notes	(149,919)	0	(383,768)
Debt financing costs paid	(495)	(5,202)	(3,705)
Proceeds from the exercise of stock options	1,286	127	2,143
Partner contributions to consolidated real estate venture	108	1,025	0
Repurchase and retirement of common shares	0	(67,320)	0
Distributions paid to shareholders	(116,636)	(115,249)	(105,795)
Net cash provided by (used in) financing activities	(535,907)	(229,455)	76,081
Increase (Decrease) in cash and cash equivalents	137,225	(200,808)	(5,705)
Cash and cash equivalents at beginning of year	56,694	257,502	263,207
Cash and cash equivalents at end of period	193,919	56,694	257,502
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2016, 2015 and 2014 of $12,835, $12,150 and $6,802, respectively	97,843	124,953	129,160
Supplemental disclosure of non-cash activity:
Dividends and distributions declared but not paid	30,032	28,249	28,871
Change in investment in real estate ventures as a result of dispositions	2,023	0	0
Change in investment in real estate ventures related to non-cash disposition of property	(25,165)	(25,127)	(5,897)
Change in operating real estate related to non-cash property disposition	0	25,127	0
Change in real estate investments related to non-cash property acquisition	0	(66,324)	0
Change in investments in joint venture related to non-cash acquisition of property	0	66,324	0
Change in investments in joint venture related to contribution of land	0	0	(1,182)
Change in receivable from settlement of acquisitions	0	0	619
Change in other liabilities from contingent consideration related to a business combination	0	1,585	0
Change in operating real estate from contingent consideration related to a business combination	0	(1,585)	0
Change in other liabilities from a deferred payment related to an asset acquisition	0	2,000	0
Change in operating real estate from a deferred payment related to an asset acquisition	0	(2,000)	0
Change in operating real estate from deconsolidation of 3141 Fairview Park Drive	44,313	0	0
Change in investment in real estate ventures from deconsolidation of 3141 Fairview Park Drive	(12,642)	0	0
Change in mortgage notes payable from deconsolidation of 3141 Fairview Park Drive	(20,582)	0	0
Change in other liabilities from deconsolidation of 3141 Fairview Park Drive	(12,384)	0	0
Change in capital expenditures financed through accounts payable at period end	8,222	(7,654)	7,336
Change in capital expenditures financed through retention payable at period end	848	6,104	6,164
Change in unfunded tenant allowance	$ 0	$ (273)	$ (955)

Consolidated Statements of Cas9

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Supplemental disclosure:
Capitalized interest	$ 12,835	$ 12,150	$ 6,802
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Supplemental disclosure:
Capitalized interest	$ 12,835	$ 12,150	$ 6,802

Consolidated Statements of Part

Consolidated Statements of Partners' Equity - USD ($) $ in Thousands	Total	BRANDYWINE OPERATING PARTNERSHIP, L.P.	General Partner Capital [Member]BRANDYWINE OPERATING PARTNERSHIP, L.P.	Series E-linked Preferred Stock [Member]BRANDYWINE OPERATING PARTNERSHIP, L.P.	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member]BRANDYWINE OPERATING PARTNERSHIP, L.P.	Noncontrolling Interest [Member]	Noncontrolling Interest [Member]BRANDYWINE OPERATING PARTNERSHIP, L.P.	Partners Equity [Member]BRANDYWINE OPERATING PARTNERSHIP, L.P.
Beginning Balance at Dec. 31, 2013		$ 1,894,949	$ 1,800,530	$ 96,850		$ (3,377)		$ 946
Beginning Balance, Shares at Dec. 31, 2013			156,731,993	4,000,000
Net income (loss)	$ 6,942	6,942	$ 6,942				$ (33)	(44)	$ 6,898
Other comprehensive income (loss)	(1,630)	(1,630)			$ (1,612)	(1,630)	(18)
Share issuance from/(to) Deferred Compensation Plan	(90)	(90)	$ (90)
Share Issuance from/(to) Deferred Compensation Plan, Shares			80,152
Issuance of LP Units		334,903	$ 334,903
Issuance of LP Units, Shares			21,850,000
Conversion of LP Units to Common Shares		3,614	$ 3,614				(3,614)
Conversion of LP Units to Common Shares, Shares			228,536
Share Choice Plan Issuance, Shares			(1,423)
Share-based compensation activity	6,847	6,847	$ 6,847
Share-based compensation activity, Shares			403,902
Adjustment of redeemable partnership units to liquidation value at period end		942	$ 942
Adjustment to non-controlling interest			(108)					108
Redemption value of limited partnership units		(3,614)	(3,614)
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Distributions to general partnership unitholders		(101,164)	(101,164)
Ending Balance at Dec. 31, 2014		2,134,755	$ 2,041,902	$ 96,850		(5,007)		1,010
Ending Balance, Shares at Dec. 31, 2014			179,293,160	4,000,000
Net income (loss)	(30,740)	(30,740)	$ (30,740)				(339)	3	$ (30,737)
Other comprehensive income (loss)	(590)	(590)			(585)	(590)	(5)
Share issuance from/(to) Deferred Compensation Plan	(2)	(2)	$ (2)
Share Issuance from/(to) Deferred Compensation Plan, Shares			88,146
Repurchase and retirement of LP units		(67,430)	$ (67,430)
Repurchase and retirement of LP units, Shares			(5,209,437)
Issuance of partnership interest in consolidated real estate venture		1,025						1,025
Bonus share issuance	125	125	$ 125
Bonus share issuance, Shares			8,447
Share Choice Plan Issuance, Shares			(1,423)
Share-based compensation activity	5,097	5,097	$ 5,097
Share-based compensation activity, Shares			509,675
Adjustment of redeemable partnership units to liquidation value at period end		1,533	$ 1,533
Adjustment to non-controlling interest			6					(6)
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Distributions to general partnership unitholders		(106,899)	(106,899)
Ending Balance at Dec. 31, 2015		1,929,977	$ 1,836,692	$ 96,850		(5,597)		2,032
Ending Balance, Shares at Dec. 31, 2015			174,688,568	4,000,000
Net income (loss)	40,501	40,501	$ 40,486				310	15
Other comprehensive income (loss)	3,475	3,475			$ 3,447	3,475	28
Share issuance from/(to) Deferred Compensation Plan	(47)	(47)	$ (47)
Share Issuance from/(to) Deferred Compensation Plan, Shares			(8,311)
Issuance of partnership interest in consolidated real estate venture	108	109					108	109
Conversion of LP Units to Common Shares		875	$ 875				$ (875)
Conversion of LP Units to Common Shares, Shares			55,303
Share-based compensation activity	5,764	5,763	$ 5,763
Share-based compensation activity, Shares			405,200
Adjustment of redeemable partnership units to liquidation value at period end		(2,622)	$ (2,622)
Adjustment to non-controlling interest			6					(6)
Redemption value of limited partnership units		(875)	(875)
Distribution to preferred shareholders	$ (6,900)	(6,900)	(6,900)
Distributions to general partnership unitholders		(110,614)	(110,614)
Ending Balance at Dec. 31, 2016		$ 1,859,642	$ 1,762,764	$ 96,850		$ (2,122)		$ 2,150
Ending Balance, Shares at Dec. 31, 2016			175,140,760	4,000,000

Consolidated Statements of Pa11

Consolidated Statements of Partners' Equity (Parenthetical) - BRANDYWINE OPERATING PARTNERSHIP, L.P. - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Distributions to general partnership unitholders (USD per share)	$ 0.63	$ 0.60	$ 0.60
General Partner Capital [Member]
Distributions to general partnership unitholders (USD per share)	$ 0.63	$ 0.60	$ 0.60

Organization of the Parent Comp

Organization of the Parent Company and The Operating Partnership	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016, owned a 99.1% 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 December 31, 2016 113 17.6 93 seven one 101 four three 2016 14 8.0 2016 Prior to the MAP Venture formation on February 4, 2016 (See Note 4, “ Investment in Unconsolidated Real Estate Ventures 2016 All references to building square footage, acres, occupancy percentage the number of buildings and tax basis are unaudited. The Company conducts its third-party real estate management services business primarily through six management companies (collectively, the “Management Companies”): Brandywine Realty Services Corporation (“BRSCO”), BTRS, Inc. (“BTRS”), Brandywine Properties I Limited, Inc. (“BPI”), BDN Brokerage, LLC (“BBL”), Brandywine Properties Management, L.P. (“BPM”) and Brandywine Brokerage Services, LLC (“BBS”). Each of BRSCO, BTRS and BPI is a taxable REIT subsidiary. As of December 31, 2016, the Operating Partnership owns, directly and indirectly, 100% of each of BRSCO, BTRS, BPI, BBL, BPM and BBS. As of December 31, 2016, the Management Companies were managing properties containing an aggregate of approximately 28.1 million net rentable square feet, of which approximately 17.6 million net rentable square feet related to Properties owned by the Company and approximately 10.5 million net rentable square feet related to properties owned by third parties and Real Estate Ventures.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Principles of Consolidation The Company consolidates variable interest entities (“VIEs”) in which it is considered to be the primary beneficiary. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or that the holders of the equity investment at risk do not have a controlling financial interest. The primary beneficiary is defined by the entity having both of the following characteristics: (i) the power to direct those matters that most significantly impacted the activities of the VIE and (ii) the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to the VIE. For entities that the Company has the obligations to fund losses, its maximum exposure to loss is not limited to the carrying amount of its investments. As of December 31, 2016, the Company’s unconsolidated real estate ventures had aggregate indebtedness to third parties of $997.5 million. These loans are generally mortgage or construction loans, most of which are non-recourse to the Company. As of December 31, 2016, the loans for which there is recourse to the Company consists of the following: (i) a $52.5 million payment guaranty on the term loan for evo at Cira; (ii) a $3.2 million payment guarantee on the $56.0 million construction loan for TB-BDN Plymouth Apartments; (iii) a joint and several cost overrun guaranty on the $88.9 million construction loan for the development project being undertaken by 1919 Market Street LP; and (iv) a $0.4 million payment guarantee on a loan provided to PJP VII. On January 31, 2017, the Company sold its 50% interest in TB-BDN Plymouth Apartments, L.P. and the Company’s $3.2 million guarantee was cancelled. See Note 21, “Subsequent Events,” When an entity is not deemed to be a VIE, the Company consolidates entities for which it has significant decision making control over the entity’s operations. The Company’s judgement with respect to its level of influence or control of an entity involves consideration of various factors including the form of the Company’s ownership interest, its representation in the entity’s governance, the size of its investment (including loans), estimates of future cash flows, its ability to participate in policy making decisions and the rights of the other investors to participate in the decision making process and to replace the Company as manager and/or liquidate the venture, if applicable. The Company’s assessment of its influence or control over an entity affects the presentation of these investments in the Company’s consolidated financial statements. In addition to evaluating control rights, the Company consolidates entities in which the outside partner has no substantive kick-out rights to remove the Company as managing member. The Company continuously assesses its determination of the primary beneficiary for each entity and assesses reconsideration events that may cause a change in the original determinations. The portion of the consolidated entities that is not owned by the Company is presented as non-controlling interest as of and during the periods consolidated. All intercompany transactions have been eliminated in consolidation. As of December 31, 2016 and 2015, the Company included in its consolidated balance sheets consolidated VIEs having total assets of $417.1 million and $422.9 million, respectively, and total liabilities of $254.6 million and $258.2 million, respectively. Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Management makes significant estimates regarding revenue, valuation of real estate and related intangible assets and liabilities, impairment of long-lived assets, land held for development, allowance for doubtful accounts and deferred costs. Operating Properties Operating properties are carried at historical cost less accumulated depreciation and impairment losses. The cost of operating properties reflects their purchase price or development cost. Acquisition costs related to business combinations are expensed as incurred, whereas the costs related to asset acquisitions are capitalized as incurred. Costs incurred for the renovation and betterment of an operating property are capitalized to the Company’s investment in that property. Ordinary repairs and maintenance are expensed as incurred. Purchase Price Allocation The Company allocates the purchase price of properties considered to be business combinations to net tangible and identified intangible assets acquired based on fair values. Above-market and below-market in-place lease values for acquired properties are recorded based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) the Company’s estimate of the fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease (including the below market fixed renewal period, if applicable). Capitalized above-market lease values are amortized as a reduction of rental income over the remaining non-cancelable terms of the respective leases. Capitalized below-market lease values are amortized as an increase to rental income over the remaining non-cancelable terms of the respective leases, including any below market fixed-rate renewal option periods that are considered probable. Other intangible assets also include in-place leases based on the Company’s evaluation of the specific characteristics of each tenant’s lease and the Company’s overall relationship with the respective tenant. The Company estimates the cost to execute leases with terms similar to the remaining lease terms of the in-place leases, including leasing commissions, legal and other related expenses. This intangible asset is amortized to expense over the remaining term of the respective leases and any fixed-rate bargain renewal periods. Company estimates of value are made using methods similar to those used by independent appraisers or by using independent appraisals. Factors considered by the Company in this analysis include an estimate of the carrying costs during the expected lease-up periods considering current market conditions and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rents at market rates during the expected lease-up periods, which primarily range from four to twelve months. The Company also considers information obtained about each property as a result of its pre-acquisition due diligence, marketing and leasing activities in estimating the fair value of the tangible and intangible assets acquired. The Company also uses the information obtained as a result of its pre-acquisition due diligence as part of its consideration of the accounting standard governing asset retirement obligations and when necessary, will record a conditional asset retirement obligation as part of its purchase price. The Company also evaluates tenant relationships on a tenant-specific basis. On certain of the Company’s acquisitions this intangible has been deemed immaterial, in which case no related intangible asset value is assigned. In the event that a tenant terminates its lease, the unamortized portion of each intangible, including in-place lease values and tenant relationship values, is charged to expense and market rate adjustments (above or below) are recorded to revenue. The Company records development acquisitions that do not meet the accounting criteria to be accounted for as business combinations at the purchase price paid. Costs directly associated with development acquisitions accounted for as asset acquisitions are capitalized as part of the cost of the acquisition. Depreciation and Amortization The costs of buildings and improvements are depreciated using the straight-line method based on the following useful lives: buildings and improvements (5 to 55 years) and tenant improvements (the shorter of (i) the life of the asset, 1 to 16 years, or (ii) the lease term). Construction-in-Progress Project costs directly associated with the development and construction of a real estate project are capitalized as construction-in-progress. Construction-in-progress also includes costs related to ongoing tenant improvement projects. In addition, interest, real estate taxes and other expenses that are directly associated with the Company’s development activities are capitalized until the property is placed in service. Interest expense is capitalized using the Company’s average interest rate. Internal direct costs are capitalized to projects in which qualifying expenditures are being incurred. Internal direct construction costs totaling $6.7 million in 2016, $7.3 million in 2015, $5.2 million in 2014 and interest totaling $10.9 million in 2016, $10.2 million in 2015, and $4.8 million in 2014 were capitalized related to development of certain properties and land holdings. During the years ended December 31, 2016, 2015 and 2014, the Company’s internal direct construction costs are comprised entirely of capitalized salaries. The following table shows the amount of compensation costs (including bonuses and benefits) capitalized for the years presented (in thousands): December 31, 2016 2015 2014 Development $ 3,182 $ 2,641 $ 1,749 Redevelopment 144 221 184 Tenant Improvements 3,391 4,429 3,261 Total $ 6,717 $ 7,291 $ 5,194 Impairment or Disposal of Long-Lived Assets The Company reviews its long-lived assets for impairment following the end of each quarter using cash flow projections and estimated fair values for each of the properties included within its impairment analysis. The Company updates leasing and other assumptions regularly, paying particular attention to properties where there is an event or change in circumstances that indicates an impairment in value. Additionally, the Company considers strategic decisions regarding the future development plans for property under development and other market factors. For long-lived assets to be held and used, the Company analyzes recoverability based on the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the assets over, in most cases, a 10-year hold period. If there is significant possibility that the Company will dispose of assets earlier, it analyzes the recoverability using a probability weighted analysis of the undiscounted future cash flows expected to be generated from the operations and eventual disposition of each asset using various possible hold periods. If the recovery analysis indicates that the carrying value of the tested property is not recoverable, the property is written down to its fair value and an impairment loss is recognized. In such case, an impairment loss is recognized in the amount of the excess of the carrying amount of the asset over its fair value. If and when the Company’s plans change, it revises its recoverability analysis to use cash flows expected from operations and eventual disposition of each asset using hold periods that are consistent with its revised plans. Estimated cash flows used in such analysis are based on the Company’s plans for the property and its views of market economic conditions. The estimates consider factors such as current and future rental rates, occupancies for the tested property and comparable properties, estimated operating and capital expenditures and recent sales data for comparable properties; most of these factors are influenced by market data obtained from real estate leasing and brokerage firms and the Company’s direct experience with the properties and their markets. The Company generally considers assets to be “held for sale” when the transaction has been approved by its Board of Trustees, or by officers vested with authority to approve the transaction, and there are no known significant contingencies relating to the sale of the property within one year of the consideration date and the consummation of the transaction is otherwise considered probable. When a property is designated as held for sale, the Company stops depreciating the property and estimate the property’s fair value, net of selling costs. If the determination is made that the estimated fair value, net of selling costs, is less than the net carrying value of the property, an impairment loss is recognized, reducing the net carrying value of the property to estimated fair value less selling costs. For periods in which a property is classified as held for sale, the Company classifies the assets of the property as held for sale on the consolidated balance sheet for such periods. The relevant accounting guidance for impairments requires that qualifying assets and liabilities and the results of operations that have been sold, or otherwise qualify as “held for sale,” be presented as discontinued operations in all periods presented if the disposal represents a strategic shift that has, or will have, a major effect on the Company’s operations and financial results. The components of the property’s net income that is reflected as discontinued operations include the net gain (or loss) upon the disposition of the property held for sale, operating results, depreciation and interest expense (if the property is subject to a secured loan). Impairment of Land Held for Development When demand for build-to-suit office space declines and the ability to sell land held for development deteriorates, or other market factors indicate a possible impairment in the recoverability of land held for development, it is reviewed for impairment by comparing its fair value to its carrying value. If the estimated sales value is less than the carrying value, the carrying value is written down to its estimated fair value. Cash and Cash Equivalents Cash and cash equivalents are highly-liquid investments with original maturities of three months or less. The Company maintains cash equivalents in money market accounts with financial institutions in excess of insured limits, but believes this risk is mitigated by only investing in or through major financial institutions. The Company does not invest its available cash balances in money market funds, as such available cash balances are appropriately reflected as cash and cash equivalents on its consolidated balance sheet. Restricted Cash Restricted cash consists of cash held as collateral to provide credit enhancement for the Company’s mortgage debt, cash for property taxes, capital expenditures and tenant improvements. Escrows also include cash held by qualified intermediaries for possible investments in like-kind exchanges in accordance with Section 1031 of the Internal Revenue Code in connection with sales of the Company’s properties. Restricted cash is included in the “Other assets” caption in the consolidated balance sheets. Accounts Receivable and Accrued Rent Receivable Generally, leases with tenants are accounted for as operating leases. Minimum annual rentals under tenant leases are recognized on a straight-line basis over the term of the related lease. The cumulative difference between lease revenue recognized under the straight-line method and contractual lease payment terms is recorded as “Accrued rent receivable, net” on the accompanying consolidated balance sheets. Included in current tenant receivables are tenant reimbursements which are comprised of amounts recoverable from tenants for common area maintenance expenses and certain other recoverable expenses that are recognized as revenue in the period in which the related expenses are incurred. As of December 31, 2016 and 2015, no tenant represented more than 10% of accounts receivable and accrued rent receivable. Tenant receivables and accrued rent receivables are carried net of the allowances for doubtful accounts of $2.4 million and $13.7 million in 2016, respectively, and $1.7 million and $14.5 million in 2015, respectively. The allowance is an estimate based on two calculations that are combined to determine the total amount reserved. First, the Company evaluates specific accounts where it has determined that a tenant may have an inability to meet its financial obligations. In these situations, the Company uses its judgment, based on the facts and circumstances, and records a specific reserve for that tenant against amounts due to reduce the receivable to the amount that the Company expects to collect. These reserves are reevaluated and adjusted as additional information becomes available. Second, a reserve is established for all tenants based on a range of percentages applied to receivable aging categories for tenant receivables. For accrued rent receivables, the Company considers the results of the evaluation of specific accounts and also considers other factors including assigning risk factors to different industries based on its tenants Standard Industrial Classification (SIC). Considering various factors including assigning a risk factor to different industries, these percentages are based on historical collection and write-off experience adjusted for current market conditions, which requires management’s judgments. Investments in Unconsolidated Real Estate Ventures Under the equity method, investments in unconsolidated Real Estate Ventures are recorded initially at cost, as Investments in unconsolidated Real Estate Ventures, and subsequently adjusted for equity in earnings, cash contributions, distributions and impairments. For Real Estate Ventures that are constructing assets to commence planned principal operations, the Company capitalizes interest expense using the Company’s weighted average interest rate of consolidated debt and its investment balance as a basis. Planned principal operations commence when a property is available to lease and at that point in time the Company ceases capitalizing interest to its investment basis. During the twelve months ended December 31, 2016, the Company capitalized interest expense of $1.9 million. In each of the twelve months ended December 31, 2015 and 2014, the Company capitalized interest expense of $2.0 million. On a periodic basis, management also assesses whether there are any indicators that the value of the Company’s investments in unconsolidated Real Estate Ventures may be other than temporarily impaired. An investment is impaired only if the value of the investment, as estimated by management, is less than the carrying value of the investment and the decline is other than temporary. To the extent that an impairment has occurred, the loss shall be measured as the excess of the carrying amount of the investment over the fair value of the investment, as estimated by management. The determination as to whether an impairment exists requires significant management judgment about the fair value of its ownership interest. Fair value is determined through various valuation techniques, including but not limited to, discounted cash flow models, quoted market values and third party appraisals. When the Company acquires an interest in or contributes assets to a real estate venture project, the difference between the Company’s cost basis in the investment and the value of the real estate venture or asset contributed is amortized over the life of the related assets, intangibles and liabilities and such adjustment is included in the Company’s share of equity in income of unconsolidated Real Estate Ventures. For purposes of cash flow presentation, distributions from unconsolidated Real Estate Ventures are presented as part of operating activities when they are considered as return on investments. Distributions in excess of the Company’s share in the cumulative unconsolidated Real Estate Ventures’ earnings are considered as return of investments and are presented as part of investing activities in accordance with the accounting standard for cash flow presentation. Deferred Costs Costs incurred in connection with property leasing are capitalized as deferred leasing costs. Deferred leasing costs consist primarily of leasing commissions and internal leasing costs that are amortized using the straight-line method over the life of the respective lease which generally ranges from 1 to 16 years. Management re-evaluates the remaining useful lives of leasing costs as economic and market conditions change. Notes Receivable The Company accounts for notes receivable on its balance sheet at amortized cost, net of allowance for loan losses. Interest income is recognized over the term of the notes receivable and is calculated based on the terms on the contractual terms of each note agreement. Notes receivable are placed on nonaccrual status when management determines, after considering economic and business conditions and collection efforts, that the loans are impaired or collection of interest is doubtful. Uncollectible interest previously accrued is recognized as bad debt expense. Interest income on nonaccrual loans is recognized only to the extent that cash payments are received. A note receivable was given to an unaffiliated third party during the third quarter of 2016 to facilitate its acquisition and development of an industrial facility located in Pennsauken, New Jersey. The loan matures three years after the payment commencement date, which is 90 days after substantial completion of the development, and bears interest at 6.3% during year one, 7.0% during year two and 8.0% during year three. The Company evaluated its investment in the note receivable under ASC 310, Receivables Deferred Financing Costs Costs incurred in connection with debt financing are capitalized as a direct deduction from the carrying value of the debt, except for costs capitalized related to the Company’s revolving credit facility, which are capitalized within “deferred costs, net” on the accompanying consolidated balance sheets. Deferred financing costs are charged to interest expense over the terms of the related debt agreements. Deferred financing costs consist primarily of loan fees which are amortized over the related loan term on a basis that approximates the effective interest method. Deferred financing costs are accelerated, when debt is extinguished, as part of “ Interest expense-amortization of deferred financing costs Revenue Recognition Rental revenue is recognized on the straight-line basis, which averages minimum rents over the terms of the leases from the later of the date of the commencement of the lease or the date of acquisition of the property subject to existing leases. The straight-line rent adjustment increased revenue by approximately $26.3 million in 2016, $21.6 million in 2015 and $13.7 million in 2014. Deferred rents on the balance sheet represent rental revenue received prior to their due dates and amounts paid by the tenant for certain improvements considered to be landlord assets that will remain as the Company’s property at the end of the tenant’s lease term. The amortization of the amounts paid by the tenant for such improvements is calculated on a straight-line basis over the term of the tenant’s lease and is a component of straight-line rental income and increased revenue by $2.1 million in 2016, $2.0 million in 2015 and $2.4 million in 2014. Lease incentives, which are included as reductions of rental revenue in the accompanying consolidated statements of operations, are recognized on a straight-line basis over the term of the lease. Lease incentives decreased revenue by $2.0 million in 2016, $1.8 million in 2015, and $1.5 million in 2014. In addition, the Company’s rental revenue is impacted by the Company’s determination of whether improvements to the properties, whether made by the Company or by the tenant, are landlord assets. The determination of whether an improvement is a landlord asset requires judgment. In making this judgment, the Company’s primary consideration is whether the improvement would be utilizable by another tenant upon move out of the improved space by the then-existing tenant. If the Company has funded an improvement that it determines not to be landlord assets, then it treats the cost of the improvement as a lease incentive. If the tenant has funded the improvement that the Company determines to be landlord assets, then the Company treats the costs of the improvement as deferred revenue and amortizes this cost into revenue over the lease term. For certain leases, the Company makes significant assumptions and judgments in determining the lease term, including assumptions when the lease provides the tenant with an early termination option. The lease term impacts the period over which the Company determines and records minimum rents and also impacts the period over which the Company amortizes lease-related costs. The Company’s leases also typically provide for tenant reimbursement of a portion of common area maintenance expenses and other operating expenses to the extent that a tenant’s pro rata share of expenses exceeds a base year level set in the lease or to the extent that the tenant has a lease on a triple net basis. Recoveries from tenants, consisting of amounts due from tenants for common area maintenance expenses, real estate taxes and other recoverable costs are recognized as revenue in the period during which the expenses are incurred. Tenant reimbursements are recognized and presented in accordance with accounting guidance which requires that these reimbursements be recorded on a gross basis because the Company is generally the primary obligor with respect to the goods and services the purchase of which gives rise to the reimbursement obligation; because the Company has discretion in selecting the vendors and suppliers; and because the Company bears the credit risk in the event they do not reimburse the Company. The Company also receives payments from third parties for reimbursement of a portion of the payroll and payroll-related costs for certain of the Company’s personnel allocated to perform services for these third parties and reflects these payments on a gross basis. The Company recognizes gains on sales of real estate at times and in amounts determined in accordance with the accounting guidance for sales of real estate. The guidance takes into account the terms of the transaction and any continuing involvement, including in the form of management, leasing of space or financial assistance associated with the properties. If the sales criteria for the full accrual method are not met, then the Company defers some or all of the gain recognition and accounts for the continued operations of the property by applying the finance, leasing, profit sharing, deposit, installment or cost recovery method, as appropriate, until the sales criteria are met. The Company derives parking revenues from leases, monthly parking and transient parking. The Company recognizes parking revenue as earned. The Company receives leasing commission income, property management fees and third party development fees. Leasing commission income is earned based on a percentage of gross rental income upon a tenant signing a lease with a third party lessor. Property management fees are recorded and earned based on a percentage of collected rents at the properties under management, and not on a straight-line basis, because such fees are contingent upon the collection of rents. The Company records development fees on a percentage of completion basis taking into account the risk associated with each project. The Company recognizes fees received for lease terminations as revenue and writes off against such revenue any deferred rents receivable. The resulting net amount is the net revenue from the early termination of the leases. When a tenant's lease for space in a property is terminated early but the tenant continues to lease such space under a new or modified lease in the property, the net revenue from the early termination of the lease is recognized evenly over the remaining life of the new or modified lease in place on that property, unless the Company cannot determine that collectability of the lease termination revenue is reasonably assured. No tenant represented greater than 10% of the Company’s rental revenue in 2016, 2015 or 2014. Income Taxes Parent Company The Parent Company has elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended (the “Code”). In order to continue to qualify as a REIT, the Parent Company is required to, among other things, distribute at least 90% of its annual REIT taxable income to its shareholders and meet certain tests regarding the nature of its income and assets. As a REIT, the Parent Company is not subject to federal and state income taxes with respect to the portion of its income that meets certain criteria and is distributed annually to its shareholders. Accordingly, a nominal provision for federal and state income taxes is included in the accompanying consolidated financial statements with respect to the operations of the Parent Company. The Parent Company intends to continue to operate in a manner that allows it to meet the requirements for taxation as a REIT. If the Parent Company fails to qualify as a REIT in any taxable year, it will be subject to federal and state income taxes and may not be able to qualify as a REIT for the four subsequent tax years. The Parent Company is subject to certain local income taxes. Provision for such taxes has been included in general and administrative expenses in the Parent Company’s Consolidated Statements of Operations and Comprehensive Income. The tax basis of the Parent Company’s assets was $3.0 billion and $3.9 billion for the years ended December 31, 2016 and 2015, respectively. The Parent Company is subject to a 4% federal excise tax if sufficient taxable income is not distributed within prescribed time limits. The excise tax equals 4% of the annual amount, if any, by which the sum of (a) 85% of the Parent Company’s ordinary income and (b) 95% of the Parent Company’s net capital gain exceeds cash distributions and certain taxes paid by the Parent Company. No excise tax was incurred in 2016, 2015 or 2014. The Parent Company has elected to treat several of its subsidiaries as taxable REIT subsidiaries (each a “TRS”). A TRS is subject to federal, state and local income tax. In general, a TRS may perform non-customary services for tenants, hold assets that the Parent Company, as a REIT, cannot hold directly and generally may engage in any real estate or non-real estate related business. The Company’s taxable REIT subsidiaries did not have significant tax provisions or deferred income tax items as of December 31, 2016 and 2015. The Protecting Americans from Tax Hikes Act (PATH Act) was enacted in December 2015, and included numerous law changes applicable to REITs. The provisions have various effective dates beginning as early as 2016. The changes have not materially impacted the Company’s operations, but the Company will continue to monitor as regulatory guidance is issued. Operating Partnership In general, the Operating Partnership is not subject to federal and state income taxes, and accordingly, no provision for income taxes has been made in the accompanying consolidated financial statements. The partners of the Operating Partnership are required to include their respective share of the Operating Partnership’s profits or losses in their respective tax returns. The Operating Partnership’s tax returns and the amount of allocable Partnership profits and losses are subject to examination by federal and state taxing authorities. If such examination results in changes to the Operating Partnership profits or losses, then the tax liability of the partners would be changed accordingly. The tax basis of the Operating Partnership’s assets was $3.0 billion and $3.9 billion for the years ended December 31, 2016 and 2015, respectively. The Operating Partnership may elect to treat one or more of its subsidiaries as REITs under Sections 856 through 860 of the Code. Each subsidiary REIT has met the requiremen

Real Estate Investments

Real Estate Investments	12 Months Ended
	Dec. 31, 2016
Real Estate [Abstract]
REAL ESTATE INVESTMENTS	3. REAL ESTATE INVESTMENTS As of December 31, 2016 and 2015 the gross carrying value of the Company’s Properties was as follows (in thousands): December 31, December 31, 2016 2015 Land $ 469,522 $ 513,268 Building and improvements 2,683,087 2,719,780 Tenant improvements 433,686 459,952 Operating properties 3,586,295 3,693,000 Assets held for sale - real estate investments (a) 73,591 794,588 Total $ 3,659,886 $ 4,487,588 (a) Real estate investments related to assets held for sale above represents gross real estate assets and does not include accumulated depreciation or other assets on the balance sheets of the properties held for sale. See Held for Sale section below. Acquisitions and Dispositions 2016 Acquisition On July 1, 2016, the Company closed on the acquisition of 34.6 acres of land located in Austin, Texas known as the Garza Ranch for a gross purchase price of $20.6 million. The Company accounted for this transaction as an asset acquisition and capitalized approximately $1.9 million of acquisition related costs and closing costs as part of land held for development on its consolidated balance sheet. The Company funded the acquisition with $20.4 million of available corporate funds, net of prorations and other adjustments. As of December 31, 2016, the Company is under agreement to sell 9.5 acres (of the 34.6 acres) to two unaffiliated third parties. As of December 31, 2016, the land under this agreement of sale did not meet the criteria to be classified as held for sale. The Company has a continuing involvement through a completion guaranty, which requires the Company, as developer, to complete certain infrastructure improvements on behalf of the buyers of the land parcels. See Note 21, “ Subsequent Events, ” for information related to the sale of 1.7 acres. Dispositions The Company sold the following properties during the twelve-month period ended December 31, 2016 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) October 13, 2016 620, 640, 660 Allendale Road King of Prussia, PA 3 156,669 $ 12,800 $ 12,014 $ 2,382 September 1, 2016 1120 Executive Plaza Mt. Laurel, NJ 1 95,183 9,500 9,241 (18 ) (b) August 2, 2016 50 East Clementon Road Gibbsboro, NJ 1 3,080 1,100 1,011 (85 ) May 11, 2016 196/198 Van Buren Street (Herndon Metro Plaza I&II) Herndon, VA 2 197,225 44,500 43,412 (752 ) (c) February 5, 2016 2970 Market Street (Cira Square) Philadelphia, PA 1 862,692 354,000 350,150 115,828 February 4, 2016 Och-Ziff Portfolio Various (d) 58 3,924,783 398,100 353,971 (372 ) (e) Total Dispositions 66 5,239,632 $ 820,000 $ 769,799 $ 116,983 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs. (b) As of June 30, 2016, the Company determined that the sale of the property was probable and classified this property as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the property exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized a provision for impairment totaling approximately $1.8 million during the three-month period ended June 30, 2016. The fair value measurement was based on the pricing in the purchase and sale agreement for the sale of the property. As the pricing in the purchase and sale agreement is unobservable, the Company determined that the inputs utilized to determine fair value for this property falls within Level 3 in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, "Fair Value Measurements and Disclosures.” (c) During the three-month period ended March 31, 2016, the Company recognized a provision for impairment totaling approximately $7.4 million on the properties. See “Held for Use Impairment” section below. The loss on sale primarily relates to additional closing costs recognized at closing . (d) Exhibit 99.2 to the Company’s Current Report on Form 8-K filed on February 10, 2016 contains a complete list of the 58 properties disposed of in the transactions with Och-Ziff Capital Management Group LLC. See Note 4, "Investment in Unconsolidated Real Estate Ventures," (e) During the three-month period ended December 31, 2015, the Company recognized a provision for impairment totaling approximately $45.4 million. The loss on sale represents additional closing costs recognized at closing The Company sold the following land parcels during the twelve-month period ended December 31, 2016 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale (a) December 2, 2016 Oakland Lot B Oakland, CA 1 0.9 $ 13,750 $ 13,411 $ 9,039 August 19, 2016 Highlands Land Mt. Laurel, NJ 1 2.0 288 284 193 January 15, 2016 Greenhills Land Reading, PA 1 120.0 900 837 - (b) Total Dispositions 3 122.9 $ 14,938 $ 14,532 $ 9,232 (a) Gain on Sale is net of closing and other transaction related costs. (b) The carrying value of the land exceeded the fair value less the anticipated costs of sale as of December 31, 2015, therefore the Company recognized an impairment loss of $0.3 million during the three-month period ended December 31, 2015. There was no gain or loss recognized on the sale during 2016. Held for Use Impairment As of December 31, 2016, the Company evaluated the recoverability of the carrying value of its properties that triggered assessment under the undiscounted cash flow model. Based on the Company’s evaluation, it was determined that due to the reduction in the Company’s intended hold period of three properties located in the Other segment, the Company would not recover the carrying values of these properties. Accordingly, the Company recorded impairment charges on these properties of $7.3 million at December 31, 2016, reducing the aggregate carrying values of the properties from $25.8 million to their estimated fair value of $18.5 million. The Company measured these impairments based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 8.75% and 9.00%, respectively. The results were comparable to indicative pricing in the market. The assumptions used to determine fair value under the income approach are Level 3 inputs in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, “ Fair Value Measurements and Disclosures. During the three-month period ended June 30, 2016, the Company evaluated the recoverability of the carrying value of its properties that triggered assessment under the undiscounted cash flow model. Based on the analysis, the Company determined that due to the reduction in the Company’s intended hold period of a property located in the Metropolitan D.C. segment, the Company would not recover the carrying values of that property. Accordingly, the Company recorded an impairment charge on the property of $3.9 million at June 30, 2016, reducing the aggregate carrying value of the property from $37.4 million to its estimated fair value of $33.5 million. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rate and discount rate of 7.75% and 8.25%, respectively. The results were comparable to indicative pricing in the market. The assumptions used to determine fair value under the income approach are Level 3 inputs in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, “ Fair Value Measurements and Disclosures. During the three-month period ended March 31, 2016, the Company evaluated the recoverability of the carrying value of the properties that triggered assessment under the undiscounted cash flow model. Based on the analysis, the Company determined that due to a reduction in the Company’s intended hold period, the Company would not recover the carrying value of two properties located in its Metropolitan D.C. segment. Accordingly, the Company recorded an impairment charge of Fair Value Measurements and Disclosures. Land Impairments As of December 31, 2016, the Company assessed the fair value of the land parcels within its Other segment that it intends to sell in the short-term and, based on that assessment, the Company determined that it would not recover the carrying value of five land parcels, consisting of 108 acres. Accordingly, the Company recorded impairment charges of $5.6 million at December 31, 2016, reducing the aggregate carrying value of the land parcels from $18.2 million to their estimated fair values of $12.6 million. The Company measured these impairments using indicative pricing in the markets in which each land parcel is located. The assumptions used to determine fair value under the market approach are Level 3 inputs in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, “Fair Value Measurements and Disclosures.” Held for Sale The following is a summary of properties classified as held for sale at December 31, 2016 but which did not meet the criteria to be classified within discontinued operations at December 31, 2016 (in thousands): Held for Sale Properties Included in Continuing Operations December 31, 2016 Metropolitan D.C. - Office (a) Other Segment - Office (b) Other Segment - Land (c) Total ASSETS HELD FOR SALE Real estate investments: Operating properties $ 21,720 $ 51,871 $ - $ 73,591 Accumulated depreciation (11,935 ) (20,981 ) - (32,916 ) Operating real estate investments, net 9,785 30,890 - 40,675 Land held for development - - 1,043 1,043 Total real estate investments, net 9,785 30,890 1,043 41,718 Total assets held for sale, net $ 9,785 $ 30,890 $ 1,043 $ 41,718 LIABILITIES HELD FOR SALE Other liabilities $ 73 $ 8 $ - $ 81 Total liabilities held for sale $ 73 $ 8 $ - $ 81 (a) As of December 31, 2016, the Company determined that the sale of three office properties in the Metropolitan D.C. segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded their fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $3.0 million during the three-month period ended December 31, 2016. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 9.00% and 10.00%, respectively. The results were comparable to indicative pricing in the market (b) As The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 9.75% and 9.75%, respectively. The results were comparable to indicative pricing in the market. (c) As The fair value measurement was based on the pricing in the purchase and sale . The sales of the Company’s fee interests in the properties referenced above do not represent a strategic shift that has a major effect on the Company's operations and financial results. As a result, the operating results of these properties remain classified within continuing operations for all periods presented. See Note 21, " Subsequent Events, 2015 Acquisitions On July 7, 2015, the Company acquired a 0.8 acre parcel of land located at 2100 Market Street in Philadelphia, Pennsylvania for $18.8 million. The Company funded $16.8 million of the purchase price with available corporate funds and the remaining $2.0 million of the purchase price was deferred until the earlier of the commencement of development or 24 months from settlement. The Company accounted for this transaction as an asset acquisition and capitalized a nominal amount of acquisition related costs and other costs as part of land inventory on its consolidated balance sheet. In connection with the purchase agreement, if certain land parcels adjacent to 2100 Market Street are acquired from unaffiliated third parties, the Company may be required to pay additional consideration to the seller of 2100 Market Street. The unaffiliated third parties are not party to this transaction and any land parcels acquired will be acquired in arm’s length transactions. The amount of additional consideration, if any, payable to the seller of 2100 Market Street cannot be determined at this time. The Company has not yet determined the timing and cost of construction for the project as of December 31, 2015. On June 22, 2015, through a series of transactions with International Business Machines ("IBM"), the Company acquired the remaining 50.0% interest in Broadmoor Austin Associates, consisting of seven office buildings and the 66.0 acre underlying land parcel located in Austin, Texas, for an aggregate purchase price of $211.4 million. The aggregate purchase price includes the carrying amount of the Company’s investment in Broadmoor Austin Associates of $66.3 million. The Company previously accounted for its 50.0% non-controlling interest in Broadmoor Austin Associates under the equity method of accounting. As a result of acquiring IBM's remaining 50.0% common interest in Broadmoor Austin Associates, the Company obtained control of Broadmoor Austin Associates and the Company's existing investment balance was remeasured based on the fair value of the underlying properties acquired and the existing distribution provisions under the relevant partnership agreement. As a result, the Company recorded a $0.8 million gain on remeasurement. Broadmoor Austin Associates contributed revenue, included in the Company’s consolidated income statements, of $26.4 million and $13.2 million and net losses of $5.2 million and $7.2 million for the twelve-months ended December 31, 2016 and 2015, respectively. The Company has treated its acquisition of the 50.0% ownership interest in Broadmoor Austin Associates as a business combination and allocated the purchase price to the tangible and intangible assets and liabilities. The Company utilized a number of sources in making estimates of fair values for purposes of allocating the purchase price to tangible and intangibles assets acquired and intangible liabilities assumed. The purchase price has been allocated as follows (in thousands): June 22, 2015 Building, land and improvements $ 163,271 Land inventory 6,045 Intangible assets acquired (a) 50,637 Below market lease liabilities assumed (b) (8,600 ) $ 211,353 Return of existing equity method investment (66,324 ) Gain on remeasurement (758 ) Net working capital assumed (450 ) Total cash payment at settlement $ 143,821 (a) Weighted average amortization period of 4.0 years. (b) Weighted average amortization period of 1.5 years The unaudited pro forma information below summarizes the Company’s combined results of operations for the years ended December 31, 2015 and 2014, respectively, as though the acquisition of Broadmoor Austin Associates was completed on January 1, 2014. The supplemental pro forma operating data is not necessarily indicative of what the actual results of operations would have been assuming the transaction had been completed as set forth above, nor do they purport to represent the Company’s results of operations for future periods (in thousands, except for per share amounts). December 31, 2015 2014 Pro forma revenue $ 612,649 $ 618,119 Pro forma income (loss) from continuing operations (36,704 ) (7,371 ) Pro forma net income (loss) available to common shareholders (43,594 ) (13,669 ) Earnings (loss) per common share from continuing operations: Basic -- as reported $ (0.17 ) $ 0.04 Basic -- as pro forma $ (0.21 ) $ (0.04 ) Diluted -- as reported $ (0.17 ) $ 0.04 Diluted -- as pro forma $ (0.21 ) $ (0.04 ) Earnings (loss) per common share: Basic -- as reported $ (0.21 ) $ - Basic -- as pro forma $ (0.24 ) $ (0.08 ) Diluted -- as reported $ (0.21 ) $ - Diluted -- as pro forma $ (0.24 ) $ (0.08 ) For the year ended December 31, 2014, $0.2 million of acquisition related costs are included as if the transaction occurred January 1, 2014. On April 6, 2015, the Company acquired a 0.8 acre parcel of land, located at 25 M Street Southeast, Washington, D.C. for $20.3 million. The Company funded the cost of this acquisition with available corporate funds. The Company capitalized $0.3 million of acquisition related costs and these costs are included as part of land inventory on the Company's consolidated balance sheet. On May 12, 2015, the Company subsequently contributed the land parcel into a newly formed real estate venture known as 25 M Street Holdings, LLC (“25 M Street”), a joint venture between the Company and Jaco 25 M Investors, LLC (“Akridge”), an unaffiliated third party, with the intent to construct a 271,000 square foot Class A office property. The Company holds a 95.0% ownership interest in 25 M Street and Akridge contributed $1.0 million in cash for its 5.0% ownership interest in 25 M Street. The $1.0 million contribution from Akridge was distributed to the Company during 2015. 25 M Street is consolidated within the Company's financial statements. See Note 4, "Investment in Unconsolidated Real Estate Ventures," On April 2, 2015, the Company acquired, from an unaffiliated third party, a property located at 618 Market Street in Philadelphia, Pennsylvania, comprised of a 330-space parking garage and 14,404 net rentable square feet for $19.4 million. Although the property is currently fully operational, the Company intends to either redevelop the existing property or demolish and fully develop the property. As of December 31, 2015, the Company had not yet begun any such development or redevelopment plans. The purchase price includes contingent consideration, recorded at fair value and payable to the seller upon commencement of development, totaling $1.6 million, and cash of $17.8 million. The Company has treated the acquisition of 618 Market Street as a business combination and allocated the purchase price to the tangible and intangible assets. The Company utilized a number of sources in making estimates of fair values for purposes of allocating the purchase price to tangible and intangible assets acquired. The Company allocated $19.2 million to building, land and improvements and $0.2 million to intangible assets. The fair value of 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 falls within Level 3 for fair value reporting. As of December 31, 2015, there was no significant changes to the inputs and the liability remains within Level 3 for fair value reporting. Dispositions The Company sold the following office properties, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2015 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain on Sale (a) December 31, 2015 5707 Southwest Parkway (Encino Trace) Austin, TX 2 320,000 $ 76,700 $ 50,158 $ 2,008 (b) December 29, 2015 Laurel Corporate Center Mt. Laurel, NJ 6 560,147 56,500 56,253 2,901 December 18, 2015 Carlsbad Properties Carlsbad, CA 3 196,075 30,400 29,568 - (c) December 18, 2015 751-761 Fifth Ave King of Prussia, PA 1 158,000 4,600 4,245 894 September 29, 2015 1000 Howard Boulevard Mt. Laurel, NJ 1 105,312 16,500 15,780 4,828 August 13, 2015 Bay Colony Office Park Wayne, PA 4 247,294 37,500 36,386 269 August 11, 2015 741 First Avenue King of Prussia, PA 1 77,184 4,900 4,640 372 June 10, 2015 100 Gateway Centre Parkway Richmond, VA 1 74,991 4,100 3,911 - (d) April 24, 2015 Christina & Delaware Corporate Centers Wilmington, DE 5 485,182 50,100 49,579 1,749 April 9, 2015 Lake Merritt Tower Oakland, CA 1 204,336 65,000 62,800 - (e) January 8, 2015 1000 Atrium Way / 457 Haddonfield Road (Atrium I / Libertyview) Mt. Laurel, NJ / Cherry Hill, NJ 2 221,405 28,300 26,778 8,981 Total Dispositions 27 2,649,926 $ 374,600 $ 340,098 $ 22,002 (f) (a) Gain on Sale is net of closing and other transaction related costs. (b) On December 31, 2015, the Company contributed two newly constructed four-story, Class A office buildings, commonly known as “Encino Trace,” containing an aggregate of approximately 320,000 square feet in Austin, Texas to one of its existing real estate ventures (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). When these two properties were contributed to the Austin Venture the Company had incurred a total of $76.7 million of development costs, representing the contribution value. The project is expected to cost $91.3 million with remaining costs fully funded by the Austin Venture. In conjunction with the contribution: (i) the Austin Venture obtained a $30.0 million mortgage loan; (ii) DRA contributed $25.1 million in net cash to the capital of the Austin Venture, including a $1.8 million working capital contribution; and (iii) the Austin Venture distributed $50.2 million to the Company and credited the Company with a $23.3 million capital contribution to the Austin Venture. In addition to the contribution of the properties, the Company also made a $1.8 million cash contribution to the Austin Venture for working capital. The Company recognized a $2.0 million gain on the contribution. Under the Encino Trace loan agreement the Austin Venture has the option, subject to certain leasing and loan-to-value requirements, to borrow an additional $29.7 million to fund tenant improvements and leasing commissions. (c) The Company recorded an impairment loss of $6.3 million for the Carlsbad office properties during the fourth quarter of 2015. As such, there was no gain at disposition for this property. (d) The Company recorded an impairment loss of $0.8 million for 100 Gateway Centre Parkway during the second quarter of 2015. As such, there was no gain at disposition for this property. (e) The Company recorded an impairment loss of $1.7 million for Lake Merritt Tower at March 31, 2015. As such, there was no gain at disposition for this property. Sales proceeds were deposited in escrow under Section 1031 of the Internal Revenue Code and applied to purchase the Broadmoor Austin portfolio. Refer to Broadmoor Austin Associates acquisition summary, above, for further details. (f) Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale. The Company sold the following land parcels, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2015 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) December 18, 2015 Two Christina Centre Wilmington, DE 1 1.6 $ 6,500 $ 5,986 $ - (b) September 1, 2015 7000 Midlantic Mt. Laurel, NJ 1 3.5 2,200 1,742 (169 ) August 31, 2015 Four Points Austin, TX 1 8.6 2,500 2,344 71 August 25, 2015 Two Kaiser Plaza Oakland, CA 1 1.0 11,100 11,016 3,117 Total Dispositions 4 14.7 $ 22,300 $ 21,088 $ 3,019 (a) Gain/(Loss) on sale includes closing and other transaction related costs. (b) The Company recorded an impairment loss of $0.3 million for Two Christina Centre during the fourth quarter of 2015. As such, there was no gain/(loss) at disposition for this land parcel. Held for Sale The following is a summary of properties classified as held for sale but which did it not meet the criteria to be classified within discontinued operations at December 31, 2015 (in thousands): Held for Sale Properties Included in Continuing Operations December 31, 2015 Och-Ziff Properties (a) 2970 Market Street (b) Greenhills Land (c) Total ASSETS HELD FOR SALE Real estate investments: Operating properties $ 526,099 $ 268,489 $ - $ 794,588 Accumulated depreciation (179,092 ) (34,489 ) - (213,581 ) Operating real estate investments, net 347,007 234,000 - 581,007 Construction-in-progress 1,915 25 - 1,940 Land held for development - - 837 837 Total real estate investments, net 348,922 234,025 837 583,784 Intangible assets 581 - - 581 Total assets held for sale, net $ 349,503 $ 234,025 $ 837 $ 584,365 LIABILITIES HELD FOR SALE Acquired lease intangibles, net $ 192 $ - $ - $ 192 Other liabilities 1,959 - - 1,959 Total liabilities held for sale $ 2,151 $ - $ - $ 2,151 (a) On February 4, 2016, the Company disposed of its interests in 58 properties located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia segments in a series of related transactions with Och Ziff Real Estate. During the fourth quarter of 2015, significant provisions were agreed upon by both the Company and Och Ziff Real Estate and, as a result, the Company determined that the sale of the portfolio was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $45.4 million during the year ended December 31, 2015. The fair value measurement was based on the pricing in the purchase and sale agreement. As the significant inputs to the model are unobservable, the Company determined that the value determined for these real estate investments fall within Level 3 for fair value reporting. (b) On December 23, 2015 the Company entered into a purchase and sale agreement to dispose of its equity interests in the office property located at 2970 Market Street in Philadelphia commonly known as 30 th (c) On January 15, 2016, the Company sold the fee interest in a 120 acre land parcel located in Berks County, Pennsylvania for $0.9 million. As of December 31, 2015, the Company classified this land parcel as held for sale in accordance with the applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $0.3 million during the year ended December 31, 2015. The sales of the Company’s equity interests and the fee interests in the properties referenced above do not represent a strategic shift that has a major effect on the Company's operations and financial results. As a result, the operating results of these properties remain classified within continuing operations for all periods presented. See Note 21, " Subsequent Events, Held for Use Impairment As of December 31, 2015, the Company evaluated the recoverability of the carrying value of its properties under the undiscounted cash flow model. Based on the analysis, it was determined that due to deteriorating operating results, increased market vacancy and a reduction in management’s intended hold period, the Company would not recover the carrying value of three properties located in the Company’s Metropolitan D.C. segment. Accordingly, the Company recorded an impairment charge of $27.5 million at December 31, 2015 reducing the aggregate carrying values of these properties from $40.4 million to their estimated fair values of $12.9 million. The Company determined these impairments based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 8.0%. The results were compared to indicative pricing in the market. The assumptions used to determine fair value are Level 3 inputs, respectively, in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, " Fair Value Measurements and Disclosures 2014 Acquisitions The Company completed each of the transactions described below with unaffiliated third parties in arms’ length transactions. On February 19, 2014, the Company acquired 54.1 acres of undeveloped land known as Encino Trace in Austin, Texas for $14.0 million. The land is fully entitled with a site plan and building permits in place allowing for the development of two four-story office buildings containing approximately 320,000 net rentable square feet. The purchase price included an in-place lease for 75% of the first building. The Company capitalized $8.4 million in construction in progress, recorded $4.6 million in land inventory and recorded a deposit for a portion of the future development fee held in escrow of $1.0 million. The Company funded the acquisition with available corporate funds. As of December 31, 2014, each of the two office buildings at Encino Trace was in development, and the Company had funded, through such date, $38.8 million, inclusive of the $14.0 million acquisition cost. During the second quarter of 2014, the Company reclassified the $4.6 million remaining in land inventory to construction in progress in connection with commencement of development of the second building. Dispositions The Company sold the following office properties, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2014 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) October 24, 2014 100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Properties) Malvern, PA 5 279,934 $ 37,900 $ 37,156 $ 203 (b) September 30, 2014 1880 Campus Commons Drive (Campus Pointe) Reston, VA 1 172,943 42,500 41,476 4,698 April 3, 2014 11305 Four Points Drive (Four Points Centre) (c) Austin, TX 2 192,396 20,750 34,392 (255 ) (c) Total Dispositions 8 645,273 $ 101,150 $ 113,024 $ 4,646 (a) Gain/(Loss) on sale is net of closing and other transaction related costs. (b) During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties. (c) On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of approximately 192,396 net rentable square feet in Austin, Texas to an existing real estate venture (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). The Company contributed the properties to the Austin Venture at an agreed upon value of $41.5 million. In conjunction with the contribution: (i) the Austin Venture obtained a $29.0 million mortgage loan; (ii) DRA contributed $5.9 million in net cash to the capital of the Austin Venture; and (iii) the Austin Venture distributed $34.4 million to the Company and credited the Company with a $5.9 million capital contribution to the Austin Venture. The Company incurred a $0.2 million loss on the contribution, driven primarily by closing costs. The Company sold the following land parcels, in each case to unaffiliated third parties in arms’ length negotiations, during the twelve-month period ended December 31, 2014 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale (a) April 16, 2014 Westpoint II Land Dallas, TX 1 5.3 $ 1,600 $ 1,505 $ 12 March 27, 2014 Rob Roy Land Austin, TX 1 16.8 3,520 3,350 1,172 Total Dispositions 2 22.1 $ 5,120 $ 4,855 $ 1,184 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs. Held for Sale Subsequent to December 31, 2014, the Company sold two office properties, commonly known as “Atrium I,” which includes 99,668 square feet of rentable space located in Mt Laurel, New Jersey and “Libertyview,” which includes 121,737 square feet of rentable space located in Cherry Hill, New Jersey. As of December 31, 2014, the Company classified Atrium I and Libertyview as held for sale in accordance with applicable accounting standard for long lived assets. Accordingly, at December 31, 2014, the properties were required to be measured at the lower of their carrying value or the estimated fair value less costs to sell. No provision for impairment was recognized at December 31, 2014, as the estimated fair value of the properties (based on the executed agreement in place at December 31, 2014) l

Investment in Unconsolidated Re

Investment in Unconsolidated Real Estate Ventures	12 Months Ended
	Dec. 31, 2016
Equity Method Investments And Joint Ventures [Abstract]
INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES	4. INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES As of December 31, 2016, the Company held ownership interests in 14 unconsolidated Real Estate Ventures for an aggregate investment balance of $281.3 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 December 31, 2016, seven of the real estate ventures owned properties that contain an aggregate of approximately 8.0 million net rentable square feet of office space; two real estate ventures owned 4.3 acres of undeveloped parcels of land; two real estate ventures owned 1.4 acres of land under active development; two real estate ventures owned residential towers that contain 345 and 321 apartment units, respectively, and one real estate venture owned an apartment complex that contains 398 units. The Company accounts for its unconsolidated interests in its Real Estate Ventures using the equity method. The Company’s unconsolidated interests range from 20% 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 $19.8 million and $18.8 million for the years ended December 31, 2016 and 2015, respectively. The Company has outstanding accounts receivable balances from its Real Estate Ventures of $1.4 million and $1.7 million for the years ended December 31, 2016 and 2015, respectively. The amounts reflected in the following tables (except for the Company’s share of equity and income) are based on the historical financial information of the individual Real Estate Ventures. The Company does not record operating losses of the Real Estate Ventures 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 Company’s investment in Real Estate Ventures as of December 31, 2016 and 2015, and the Company’s share of the Real Estate Ventures’ income (loss) for the years ended December 31, 2016 and 2015 was as follows (in thousands): Carrying Amount Company's Share of Real Estate Venture Income (Loss) Real Estate Venture Debt at 100% Ownership Percentage (a) 2016 2015 2016 2015 2016 2015 Current Interest Rate Debt Maturity Office Properties Brandywine-AI Venture LLC (b) 50% $ 67,809 $ 50,760 $ (5,895 ) $ (229 ) $ 131,539 $ 132,717 3.96 % (c) DRA (G&I) Austin (d) 50% 52,886 60,427 (1,880 ) (1,235 ) 405,734 410,066 3.36 % (e) MAP Venture (f) 50% 20,893 - (4,218 ) - 180,800 - L+6.25% Feb 2018 Four Tower Bridge 65% 2,286 1,684 602 211 9,961 10,162 5.20 % Feb 2021 PJP VII 25% 980 872 233 211 4,956 5,621 L+2.65% Dec 2019 PJP II 30% 532 435 97 32 2,893 3,201 6.12 % Nov 2023 PJP VI 25% 142 45 97 151 7,652 7,918 6.08 % Apr 2023 1000 Chesterbrook Blvd. (g) - 1,895 160 117 - 23,610 PJP V (g) - 305 127 189 - 5,035 Invesco, L.P. (g) - - 261 349 - - Broadmoor Austin Associates (g) - - - (377 ) - - Coppell Associates (h) - (1,130 ) 12 84 - 15,515 Other HSRE-BDN I, LLC (d) 50% 21,228 15,003 843 (188 ) 105,000 95,562 L+2.25% Oct 2019 TB-BDN Plymouth Apartments 50% 12,450 12,338 119 (252 ) 53,967 50,964 L+1.70% Dec 2017 Brandywine 1919 Ventures (d) (i) 50% 27,462 29,086 (1,529 ) - 79,250 19,411 L+2.00% Oct 2018 Residence Inn Tower Bridge (g) - - - 367 - - Development Properties 4040 Wilson 50% 36,356 36,626 (270 ) (106 ) 1,004 - L+2.40% Mar 2019 51 N Street 70% 20,318 16,725 (114 ) - - - 1250 First Street Office 70% 17,304 14,312 (15 ) - - - Seven Tower Bridge 20% 685 491 (133 ) (135 ) 14,710 14,789 3.71 % (j) $ 281,331 $ 239,874 $ (11,503 ) $ (811 ) $ 997,466 $ 794,571 (a) Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable. (b) See “ Brandywine AI Venture: 3141 Fairview Park Drive” section below for information discussing activity that occurred during 2016 relating to this venture. (c) The debt for these properties is comprised of three fixed rate mortgages: (1) $37.9 million with a 4.40% fixed interest rate due January 1, 2019, (2) $27.1 million with a 4.65% fixed interest rate due January 1, 2022, and (3) $66.5 million with a 3.22% fixed interest rate due August 1, 2019, resulting in a time weighted average rate of 3.96%. (d) The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “ Evo at Cira South Venture” section below for further details on these transactions. (e) The debt for these properties includes seven mortgages: (1) $33.9 million that was swapped to a 1.59% fixed rate (or an all-in fixed rate of 3.52% incorporating the 1.93% spread) due November 1, 2018, (2) $54.7 million that was swapped to a 1.49% fixed rate (or an all-in rate of 3.19% incorporating the 1.70% spread) due October 15, 2018, (3) $137.0 million that was swapped to a 1.43% fixed rate (for an all-in fixed rate of 3.44% incorporating the 2.01% spread) due November 1, 2018, (4) $29.0 million with a 4.50% fixed interest rate due April 6, 2019, (5) $34.3 million with a 3.87% fixed interest rate due August 6, 2019, (6) $86.7 million that was swapped to a 1.36% fixed rate (or all-in fixed rate of 3.36% incorporating the 2.00% spread) due February 10, 2020, and (7) $30.0 million with a rate of LIBOR + 1.85% with a cap of 2.75% due January 1, 2021, resulting in a time and dollar weighted average rate of 3.36%. (f) In order to fulfill interest rate protection requirements, a LIBOR interest rate cap of 1.75% was purchased, effective February 3, 2016 and maturing February 9, 2018, for a notional amount of $200.8 million. There are three options to extend the maturity date of the debt for three successive terms, each year representing a separate option. (g) The Company liquidated its 25% ownership interest in the PJP V real estate venture on September 22, 2016. On June 30, 2016, the Company liquidated its 50% ownership interest in the venture known as 1000 Chesterbrook. The ownership interest in Invesco, L.P. was sold prior to December 31, 2015, and on August 19, 2016, the Company assigned its residual profits interest to the general partner of Invesco. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2016 dispositions. (h) Carrying amount represents the negative investment balance of the venture that was included in other liabilities as of December 31, 2015. The ownership interest in this venture was disposed of on January 29, 2016. (i) The stated rate for the construction loan is LIBOR + 2.00%. It is further reduced to 1.75% upon reaching 90% residential occupancy and commencement of the lease in the retail space. To fulfill interest rate protection requirements, an interest rate cap was purchased at 4.50%. (j) Comprised of two fixed rate mortgages totaling $8.0 million that mature on March 1, 2017 and accrue interest at a current rate of 7.00%, a $0.8 million 3.00% fixed rate loan through its September 1, 2025 maturity, a $2.0 million 4.00% fixed rate loan with interest only through its February 7, 2017 maturity and a $3.9 million 3.25% fixed rate loan with interest only beginning March 11, 2018 through its March 11, 2020 maturity, resulting in a time and dollar weighted average rate of 3.42%. The following is a summary of the financial position of the Real Estate Ventures as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Net property $ 1,483,067 $ 1,258,999 Other assets 231,972 158,672 Other liabilities 129,486 69,028 Debt, net 989,738 794,571 Equity 595,815 554,072 Company’s share of equity (Company’s basis) (a) (b) $ 281,331 $ 241,004 (a) 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. (b) Does not include the negative investment balance of one real estate venture totaling $1.1 million as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture on January 29, 2016. See “ Coppell Associates The following is a summary of results of operations of the Real Estate Ventures in which the Company had interests as of December 31, 2016, 2015 and 2014 (in thousands): Years Ended December 31, 2016 2015 2014 Revenue $ 214,452 $ 164,928 $ 147,236 Operating expenses (110,265 ) (70,136 ) (61,268 ) Provision for impairment (a) (10,476 ) - - Interest expense, net (43,283 ) (34,584 ) (36,511 ) Depreciation and amortization (85,738 ) (68,100 ) (57,109 ) Net loss (b) $ (35,310 ) $ (7,892 ) $ (7,652 ) Equity in loss of Real Estate Ventures $ (11,503 ) $ (811 ) $ (790 ) (a) During the year ended December 31, 2016, Brandywine - AI Venture LLC recorded a property level impairment charge of $10.4 million. See additional details in the “Station Square Impairment” disclosure below. (b) During the year ended December 31, 2016, there were $7.1 million of acquisition deal costs related to the formation of the MAP Venture. As of December 31, 2016, the aggregate principal payments of recourse and non-recourse debt payable to third-parties are as follows (in thousands): 2017 $ 72,520 2018 485,847 2019 274,445 2020 92,261 2021 40,498 Thereafter 31,895 Total principal payments 997,466 Net deferred financing costs (7,728 ) Outstanding indebtedness $ 989,738 Brandywine - AI Venture: 3141 Fairview Park Drive On December 20, 2011, the Company formed a real estate venture, Brandywine - AI Venture LLC, (the "AICC Venture"), with Current Creek Investments, LLC ("Current Creek"), a wholly-owned subsidiary of Allstate Insurance Company. The Company and Current Creek each own a 50% interest in the AICC Venture. The AICC Venture owns three office properties, which the Company contributed to the AICC Venture upon its formation. The contributed office properties contain an aggregate of 587,317 net rentable square feet and consist of 3130 and 3141 Fairview Park Drive, both located in Falls Church, Virginia, and 7101 Wisconsin Avenue located in Bethesda, Maryland. The Company maintained a regional management and leasing office at 3141 Fairview Park Drive. Consistent with the other four properties owned by the AICC Venture, financial control was shared, however, pursuant to the accounting standard for sales-leaseback transactions, the lease that the Company maintained at 3141 Fairview Park Drive resulted in the Company having continuing involvement that required 3141 Fairview Park Drive and its related operations to be consolidated by the Company under the financing method of accounting for sales of real estate. At formation, the Company concluded under ASC 810, Consolidations On August 31, 2016, the Company terminated its lease for the regional management and leasing office at 3141 Fairview Park Drive. Accordingly, the Company no longer has a continuing involvement, other than the equity method investment and property management agreement, with 3141 Fairview Park Drive and recorded the partial sale under the full accrual method of accounting. As a result of the sale accounting, the Company deconsolidated net assets of $45.6 million, a mortgage loan of $20.6 million and a financing liability of $12.4 million related to the property from its consolidated balance sheet and recorded a $12.6 million equity method investment. Upon recognizing the sale, there was no gain or loss, as 3141 Fairview Park Drive was impaired to its fair value during the second quarter of 2016. On September 30, 2016, the Company funded a capital call totaling $10.3 million to the AICC Venture for its 50% share of the mortgage debt on 3141 Fairview Park Drive. Subsequently, the AICC Venture funded $20.6 million for the repayment of its mortgage debt. The Company determined that the partial sale recognition does not have an impact on the accounting standard for VIEs because the underlying real estate venture agreements are unchanged. The Venture is not a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company continues to use the voting interest model under the accounting standard for consolidation in order to determine whether to consolidate the Venture. Based upon each member’s substantive participating rights over the activities of the Venture under its operating and related agreements, it is not consolidated by the Company, and is accounted for under the equity method of accounting. Brandywine - AI Venture: Station Square Impairment On July, 10, 2012, Brandywine – AI Venture (the “AISS Venture”), an unconsolidated real estate venture in which the Company owns a 50% interest, acquired a three building office portfolio totaling 497,896 net rentable square feet in Silver Spring, Maryland (“Station Square”) valued at $120.6 million. During the period ended September 30, 2016, the AISS Venture recorded a $10.4 million held for use impairment charge related to Station Square, which is included in the Company’s Metropolitan D.C. segment. The Company's share of this impairment charge was $5.2 million and is reflected in equity in loss of Real Estate Ventures in its consolidated statement of operations for the period ended December 31, 2016. The fair value of the Station Square properties was primarily determined based on offers received for the properties. The remaining properties in the AISS Venture were evaluated for impairment, and based on an undiscounted cash flow analysis, no additional other than temporary impairment was identified. All of the inputs used to determine the above-mentioned impairment charges are categorized Level 3, as previously defined. The Company evaluated for other than temporary impairment in its investment in the AISS Venture in accordance with ASC 323, Investments - Equity Method and Joint Ventures PJP V On September 22, 2016, the real estate venture known as PJV V sold its office property, comprised of 73,997 square feet, located in Charlottesville, Virginia. Also on September 22, 2016, using proceeds from the sale, the Company liquidated its entire 25% interest in the real estate venture for $3.4 million, net of closing costs. The carrying amount of the Company’s investment was $0.2 million at the time of sale, resulting in a recognized gain of $3.2 million related to the disposition. Invesco Venture On August 19, 2016, the Company assigned its residual profits interest in an unconsolidated real estate venture known as Invesco, L.P. to the general partner of Invesco L.P. for $7.0 million. At the time of sale, the Company’s investment basis in Invesco, L.P. was zero and the Company held no other ownership interest. As a result, the Company recorded the entire amount of the proceeds received as a gain on sale of unconsolidated real estate ventures in its consolidated statement of operations. 1000 Chesterbrook On June 30, 2016, the real estate venture known as 1000 Chesterbrook sold its office property, comprised of 172,286 square feet, located in Berwyn, Pennsylvania for a sales price of $32.1 million. As of June 30, 2016, the Company owned a 50% interest in the 1000 Chesterbrook real estate venture. The proceeds to 1000 Chesterbrook, net of closing costs, proration adjustments and $23.2 million of debt assumed by the buyer, were $9.8 million. The Company recorded $3.2 million for its proportionate share of the Venture’s gain which is reflected in “Gain on Real Estate Venture transactions” in the accompanying consolidated statement of operations. The proceeds from the sale, along with $0.2 million of working capital, were distributed to the Company during the third quarter of 2016. evo at Cira Centre South Venture On January 25, 2013, the Company formed HSRE-Campus Crest IX Real Estate Venture (“evo at Cira”), a joint venture among the Company and two unaffiliated third parties: Campus Crest Properties, LLC (“Campus Crest”) and HSRE-Campus Crest IXA, LLC (“HSRE”). evo at Cira constructed a 33-story, 850-bed student housing tower located in the University City submarket of Philadelphia, Pennsylvania. Each of the Company and Campus Crest owns a 30% interest in evo at Cira and HSRE owns a 40% interest. evo at Cira developed the project on a one-acre land parcel held under a long-term ground lease with a third party lessor. The Company contributed to evo at Cira its tenancy rights under a long-term ground lease, together with associated development rights, at an agreed-upon value of $8.5 million. The Company’s historical cost basis in the development rights that it contributed to the evo at Cira was $4.0 million, thus creating a $4.5 million basis difference at December 31, 2013 between the Company’s initial outside investment basis and its $8.5 million initial equity basis. As this basis difference is not related to a physical land parcel, but rather to development rights to construct evo at Cira, the Company will accrete the basis difference as a reduction of depreciation expense over the life of evo at Cira’s assets. On March 2, 2016, the Company paid $12.8 million of cash and HSRE paid $6.6 million of cash to purchase Campus Crest’s entire 30% interest in evo at Cira and, as a result, each of the Company and HSRE owns a 50% interest in evo at Cira. Subsequent to the transaction, the Company’s investment basis in evo at Cira is $28.3 million. In conjunction with the purchase, the Company and HSRE entered into an amended and restated operating agreement to govern their rights and obligations as sole members of evo at Cira. On June 10, 2016, evo at Cira refinanced its $97.8 million construction facility maturing July 25, 2016 with a $117.0 million term loan bearing interest at LIBOR + 2.25% capped at a total maximum interest of 5.25% and maturing on October 31, 2019, with options to extend the term to June 30, 2021. evo at Cira received an advance of $105.0 million at closing. The additional $12.0 million capacity under the term loan may be funded if certain criteria relating to the operating performance of the student housing tower are met. The term loan is secured by a leasehold mortgage that holds absolute assignment of leases and rents. Subsequent to refinancing and the receipt of amounts in escrow under the construction loan, evo at Cira distributed $6.3 million to the Company. The Company accounted for its investment in evo at Cira under the equity method of accounting. Based upon the reconsideration event caused by the refinancing of evo at Cira’s construction facility, the Company reassessed its consolidation conclusion. The Company determined that this Real Estate Venture is no longer a VIE in accordance with the accounting standard for the consolidation of VIEs because evo at Cira, through the refinancing of the construction facility and without further support from the Company or HSRE, demonstrated that it has sufficient equity at risk to finance its activities. As a result, the Company used the voting interest model under the accounting standard for consolidation in order to determine whether to consolidate evo at Cira. Based upon each member's substantive participating rights over the activities that significantly impact the operations and revenues of evo at Cira under the operating agreement and related agreements, evo at Cira is not consolidated by the Company, and is accounted for under the equity method of accounting. As a result of this transaction, the Company did not gain a controlling financial interest over evo at Cira; therefore, it was not required to remeasure its previously held equity interest to fair value at the date that it acquired the additional equity interest. MAP Venture On February 4, 2016, Brandywine Operating Partnership, L.P., together with subsidiaries of the Operating Partnership, entered into a series of related transactions (the “Och-Ziff Sale”) with affiliates of Och-Ziff Capital Management Group LLC (“Och-Ziff”) that resulted in the disposition by the Company of 58 office properties that contain an aggregate of 3,924,783 square feet for an aggregate purchase price of $398.1 million. The 58 properties are located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia. The related transactions involved: (i) the sale by the Company to MAP Fee Owner LLC, an affiliate of Och-Ziff (the “O-Z Land Purchaser”), of 100% of the Company’s fee interests in the land parcels (the “Land Parcels”) underlying the 58 office properties, together with rights to be the lessor under long-term ground leases (the “Ground Leases”) covering the Land Parcels and; (ii) the Company’s formation of MAP Ground Lease Venture LLC (the “MAP Venture”) with MAP Ground Lease Holdings The MAP Venture leases the Land Parcels from O-Z Land Purchaser through a ground lease that extends through February 2115. Annual payments by the MAP Venture, as tenant under the Ground Leases, initially total $11.9 million and increase 2.5% annually through November 2025. At closing on February 4, 2016, the MAP Venture obtained a third party non-recourse debt financing of approximately $180.8 million secured by mortgages on the Buildings of the MAP Venture. As a result of this transaction, the Company received $354.0 million in proceeds and maintain a 50% ownership interest in the MAP Venture valued as of February 4, 2016 at $25.2 million, which holds the leasehold interest in the Buildings. The MAP Venture was formed as a limited liability company in which the Company has been designated as the Managing Member. In addition, through an affiliate, the Company provides property management services at the Buildings on behalf of the MAP Venture for a market based management fee. The Company has determined that the MAP Venture is a VIE in accordance with the accounting standard for consolidation of VIE’s. As a result, the Company used the VIE model under the accounting standard for consolidations to determine if it will consolidate the MAP Venture. Based on the provisions in the limited liability company agreement, the Company determined that it shares with O-Z Venture Partner the power to control the activities that most significantly impact the economics of the MAP Venture. Since control is shared, the Buildings were deconsolidated by the Company and accounted for under the equity method of accounting. The Company is not required to fund the operating losses of the MAP Venture. Accordingly, it can only incur losses equal to its investment basis in the MAP Venture. The Company has determined that this transaction does not represent a significant shift in the Company’s operations that has a major impact on the Company’s economic performance. As a result, the properties are not classified as discontinued operations on the consolidated financial statements. Coppell Associates On January 29, 2016, the Company sold its entire 50% interest in an unconsolidated real estate venture known as Coppell Associates. The proceeds to the Company, net of closing costs and related debt payoff, were $4.6 million. The carrying amount of the Company’s investment in Coppell Associates was a $1.1 million liability at the sale date, resulting in a $5.7 million gain on sale of its interest in the real estate venture. The investment was in a liability position because the Company, as a general partner, was required to fund losses of Coppell Associates. The negative investment balance represented the Company’s share of unfunded cumulative losses incurred in excess of its investment basis as of the date of sale. Residence Inn Tower Bridge On December 30, 2015, the Company sold its entire 50% ownership interest in an unconsolidated real estate venture known as Residence Inn Tower Bridge (the “Residence Inn”). The proceeds to the Company, net of closing costs and related debt payoff, were $6.1 million. The carrying amount of the Company’s investment in the Residence Inn amounted to $0.9 million at the sale date, resulting in a $5.2 million gain on sale of its interest in the Real Estate Venture. JBG Ventures On May 29, 2015, the Company and an unaffiliated third party, JBG/DC Manager, LLC ("JBG"), formed 51 N 50 Patterson, Holdings, LLC Venture ("51 N Street") and 1250 First Street Office, LLC Venture ("1250 First Street"), as real estate ventures, with the Company owning a 70.0% interest and JBG owning a 30.0% interest in each of the two ventures. At formation, the Company and JBG made cash contributions of $15.2 million and $6.5 million, respectively, to 51 N Street, which was used to purchase 0.9 acres of undeveloped land. At formation, the Company and JBG made cash capital contributions of $13.2 million and $5.7 million, respectively, to 1250 First Street, which was used to purchase 0.5 acres of undeveloped land. Based upon the facts and circumstances at formation of each of the two ventures with JBG, the Company determined that each venture is a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company used the variable interest model under the accounting standard for consolidation in order to determine whether to consolidate the JBG Ventures. JBG is the managing member of the ventures, and pursuant to the operating and related agreements, major decisions require the approval of both members. Based upon each member's shared power over the activities of each of the two ventures, which most significantly impact the economics of the ventures, neither venture is consolidated by the Company. Each venture is accounted for under the equity method of accounting. Broadmoor Austin Associates On June 22, 2015, the Company became the sole owner of Broadmoor Austin Associates upon the Company's acquisition from an unaffiliated third party of the remaining 50.0% ownership interest in Broadmoor Austin Associates. Broadmoor Austin Associates owns seven office buildings in Austin, Texas. See Note 3, " Real Estate Investments 25 M Street (Akridge) On May 12, 2015, the Company contributed the parcel of land purchased on April 9, 2015 into a newly formed real estate venture known as 25 M Street, a joint venture between the Company and Akridge, an unaffiliated third party. See Note 3, " Real Estate Investments," Based on the facts and circumstances at formation of 25 M Street, the Company determined that 25 M Street is a variable interest entity (VIE) in accordance with the accounting standard for consolidation of VIEs. Accordingly, the Company used the variable interest model under the accounting standard for consolidation in order to determine whether to consolidate 25 M Street. Under the operating and related agreements the Company has the power to control substantially all of the activities which most significantly impact the economics of 25 M Street, and accordingly, 25 M Street is consolidated within the Company’s financial statements. As of December 31, 2016 and December 31, 2015, the carrying value of the project, which is included in the land held for development caption of the consolidated balance sheets, was $22.4 million and $20.5 million, respectively. DRA - PA Venture On December 19, 2007, the Company formed G&I Interchange Office LLC, a real estate venture (the “Interchange Venture”), with an unaffiliated third party, G&I VI Investment Interchange Office LLC (“G&I VI”), an investment vehicle advised by DRA Advisors LLC. The Interchange Venture owned 29 office properties containing an aggregate of 1,611,961 net rentable square feet located in Montgomery, Lehigh and Bucks counties, Pennsylvania. The Company contributed these 29 properties to the Interchange Venture upon the Interchange Venture's formation and in exchange for the contribution received a cash distribution from the Venture and a 20.0% ownership interest in the Interchange Venture. On February 27, 2015, the Interchange Venture entered into a forbearance agreement with an unaffiliated lender that held a nonrecourse mortgage on the Venture's assets. The loan matured on January 1, 2015. On August 12, 2015, the lender sold the properties to an unaffiliated third-party purchaser under the forbearance agreement and assumed the proceeds. Commensurate with the sale, the Interchange Venture was dissolved. 1919 Ventures On January 20, 2011, the Company acquired a one acre parcel of land in Philadelphia, Pennsylvania for $9.3 million. The Company thereafter contributed the acquired land into a then newly-formed general partnership, referred to below as “1919 Ventures” in return for a 50.0% general partner interest, with the remaining 50.0% interest owned by an unaffiliated third party, who contributed cash in exchange for its interest. On October 15, 2014, the Company acquired the 50% interest of the unaffiliated third party at fair value, which approximates carrying value. No remeasurement gain or loss on the Company’s previous investment was recorded at that time. On October 21, 2014, the Company admitted an unaffiliated third party, LCOR/CalSTRS (“LCOR”) into 1919 Ventures, for $8.2 million, representing a 50% interest and, reflecting an agreed upon $16.4 million valuation of the land and improvements incurred by the Company on behalf of 1919 Ventures. After giving effect to settlement date contributions, distributions and credits, the Company and LCOR had each made, as of October 21, 2014, an additional $5.2 million capital contribution to 1919 Ventures for closing costs and development. See Item 1., “Developments – 1919 Ventures” As of December 31, 2016, $79.3 million was outstanding on the construction loan and equity contributions of $29.6 million had been funded by each of the Company and LCOR. Based upon the facts and circumstances at formation of 1919 Ventures, the Company determined that 1919 Ventures is a VIE in accordance with the accounting standard for the consolidation of VIEs since the equity investment at risk is not sufficient to permit the entity to finance its activities without additional financial support. The initial equity contributed to this entity was not sufficient to fully finance the real estate construction as development costs are funded by the partners throughout the construction period. The Company determined that it was not the primary beneficiary of this VIE based on the fact that the Company has shared control of this entity along with the entity’s partner and therefore does not have controlling financial interests in this VIE. Austin Venture On October 16, 2013, the Company contributed a portfolio of seven office properties containing an aggregate of 1,398,826 rentable square feet located in Austin, Texas (the “Austin Properties”) to a newly-formed joint venture (the “Austin Venture”) with G&I VII Austin Office LLC (“DRA”). DRA and the Company, based on arm’s-length negotiation, agreed to an aggregate gross sales price of $330.0 million subject to an obligation on the Company’s part to fund the first $5.2 million of post-closing capital expenditures, of which $0.8 million was funded by the Company during 2013 and the remaining $4.4 million was funded by the Company during the twelve months ended December 31, 2014. DRA owns a 50% interest in the Austin Venture and the Company owns a 50% interest in the Austin Venture, subject to the Company’s right to receive up to an additional 10% of distributions. At the closing the Austin Venture incurred third party debt financing of approximately $230.6 million secured by mortgages on the Austin Properties and used proceeds of this financing together with $49.7 million of ca

Deferred Costs

Deferred Costs	12 Months Ended
	Dec. 31, 2016
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
DEFERRED COSTS	5. DEFERRED COSTS As of December 31, 2016 and 2015, the Company’s deferred costs (assets) were comprised of the following (in thousands): December 31, 2016 Total Cost Amortization Deferred Costs, net Leasing costs $ 146,135 $ (56,942 ) $ 89,193 Financing costs - Revolving Credit Facility 3,595 (1,446 ) 2,149 Total $ 149,730 $ (58,388 ) $ 91,342 December 31, 2015 Total Cost Accumulated Amortization Deferred Costs, net Leasing costs $ 165,741 $ (67,342 ) $ 98,399 Financing costs - Revolving Credit Facility 3,578 (558 ) 3,020 Total $ 169,319 $ (67,900 ) $ 101,419 During the years ended December 31, 2016, 2015 and 2014, the Company capitalized internal direct leasing costs of $5.0 million, $6.6 million and $7.1 million, respectively, in accordance with the accounting standard for the capitalization of leasing costs. Brokerage Commission Payments to Related Party In May 2015, the Company leased approximately 228,000 square feet of office space (the “2015 Lease”) to a third-party commercial tenant represented by a commercial real estate broker named WDL-EL Real Estate Advisory Group, LLC, which does business as “NorthMarq Advisors” (“NorthMarq”). Walter D’Alessio, who served until February 17, 2017 as our Chairman and Lead Independent Director, owns a 33.3% membership interest in WDL Real Estate Advisory Group, LLC (“WDL”), which in turn owns a 49% interest in NorthMarq. Mr. D’Alessio is also a Principal of NorthMarq and Chairman of the Board of the tenant. The tenant maintained a long-standing brokerage relationship with NorthMarq that pre-dated the Company’s commencement of discussions as to the 2015 Lease, and NorthMarq acted as the tenant’s exclusive broker in connection with the lease. Consistent with customary practice in the commercial real estate industry, the Company paid the tenant’s brokerage commission in the amount of $4.2 million, with one-half paid to NorthMarq in 2015 upon signing of the lease and the balance paid to NorthMarq in 2016 upon the tenant’s occupancy of the leased premises. As a principal of NorthMarq, Mr. D’Alessio received payments from NorthMarq aggregating approximately $1.0 million in connection with the brokerage commission, with one-half paid in 2015 and the balance paid in 2016.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	6. INTANGIBLE ASSETS As of December 31, 2016 and 2015, the Company’s intangible assets were comprised of the following (in thousands): December 31, 2016 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 142,889 $ (75,696 ) $ 67,193 Tenant relationship value 13,074 (10,167 ) 2,907 Above market leases acquired 4,718 (2,340 ) 2,378 Total intangible assets, net $ 160,681 $ (88,203 ) $ 72,478 Acquired lease intangibles, net: Below market leases acquired $ 37,579 $ (19,460 ) $ 18,119 December 31, 2015 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 161,276 $ (57,063 ) $ 104,213 Tenant relationship value 20,117 (15,580 ) 4,537 Above market leases acquired 5,333 (1,879 ) 3,454 186,726 (74,522 ) 112,204 Assets held for sale (2,854 ) 2,273 (581 ) Total intangible assets, net $ 183,872 $ (72,249 ) $ 111,623 Acquired lease intangibles, net: Below market leases acquired $ 50,025 $ (24,178 ) $ 25,847 Assets held for sale (1,069 ) 877 (192 ) Total acquired lease intangibles, net $ 48,956 $ (23,301 ) $ 25,655 For the years ended December 31, 2016, 2015, and 2014, the Company accelerated the amortization approximately $0.6 million, $0.5 million and $0.8 million, respectively, of intangible assets as a result of tenant move-outs prior to the end of the associated lease term. For the years ended December 31, 2016, 2015, and 2014, the Company accelerated amortization of a nominal amount of intangible liabilities as a result of tenant move-outs. As of December 31, 2016, the Company’s annual amortization for its intangible assets/liabilities, assuming no early lease terminations, are as follows (dollars in thousands): Assets Liabilities 2017 $ 19,663 $ 3,323 2018 11,754 2,196 2019 10,536 1,885 2020 8,457 1,337 2021 5,971 807 Thereafter 16,097 8,571 Total $ 72,478 $ 18,119

Debt Obligations

Debt Obligations	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
DEBT OBLIGATIONS	7. DEBT OBLIGATIONS The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at December 31, 2016 and 2015 (in thousands): December 31, 2016 December 31, 2015 Effective Interest Rate Maturity Date MORTGAGE DEBT: 3141 Fairview Park Drive (a) $ - $ 20,838 4.25 % Jan 2017 Two Logan Square 86,012 86,886 3.98 % (b) May 2020 One Commerce Square 127,026 130,000 3.64 % (c) Apr 2023 Two Commerce Square 112,000 112,000 4.51 % (d) Apr 2023 IRS Philadelphia Campus (e) - 177,425 7.00 % Sep 2030 Cira South Garage (e) - 35,546 7.12 % Sep 2030 Principal balance outstanding 325,038 562,695 Plus: fair market value premium (discount), net (2,761 ) (3,198 ) Less: deferred financing costs (728 ) (13,744 ) Mortgage indebtedness $ 321,549 $ 545,753 UNSECURED DEBT Seven-Year Term Loan - Swapped to fixed $ 250,000 $ 250,000 3.72 % Oct 2022 $250.0M 6.00% Guaranteed Notes due 2016 (f) - 149,919 5.95 % Apr 2016 $300.0M 5.70% Guaranteed Notes due 2017 300,000 300,000 5.68 % May 2017 $325.0M 4.95% Guaranteed Notes due 2018 325,000 325,000 5.13 % Apr 2018 $250.0M 3.95% Guaranteed Notes due 2023 250,000 250,000 4.02 % Feb 2023 $250.0M 4.10% Guaranteed Notes due 2024 250,000 250,000 4.33 % Oct 2024 $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 2.75 % Mar 2035 Indenture IB (Preferred Trust I) 25,774 25,774 3.30 % Apr 2035 Indenture II (Preferred Trust II) 25,774 25,774 3.09 % Jul 2035 Principal balance outstanding 1,703,610 1,853,529 Plus: original issue premium (discount), net (4,678 ) (5,714 ) Less: deferred financing costs (7,369 ) (8,851 ) Total unsecured indebtedness $ 1,691,563 $ 1,838,964 Total Debt Obligations $ 2,013,112 $ 2,384,717 (a) On August 31, 2016, the Company deconsolidated 3141 Fairview Park Drive and began accounting for it under the equity method of accounting as part of Brandywine - AI Venture LLC, an unconsolidated real estate venture in which the Company holds At December 31, 2015, this balance represented the full debt amount of the property, as it was consolidated at that time. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further details. (b) On April 7, 2016, the Company closed on an $86.9 million first mortgage financing on Two Logan Square, a 708,844-square foot office property located in Philadelphia, Pennsylvania. Proceeds of the loan were used to repay, without penalty, the $86.6 million principal balance of the former Two Logan Square first mortgage loan, which had a 7.57% effective interest rate. (c) This loan was assumed upon acquisition of the related properties on December 19, 2013. On December 29, 2015, the Company refinanced the debt increasing the principal balance to $130.0 million and extended the term from the scheduled maturity from January 6, 2016 to April 5, 2023. The effective interest rate as of December 31, 2015 was 3.64%. A default under this loan will also constitute a default under the loan outstanding on Two Commerce Square. This loan is also secured by a lien on Two Commerce Square. (d) This loan was assumed upon acquisition of the related property on December 19, 2013. The interest rate reflects the market rate at the time of acquisition. A default under this loan will also constitute a default under the loan outstanding on One Commerce Square. This loan is also secured by a lien on One Commerce Square. (e) On January 14, 2016, the Company funded $265.8 million to prepay two mortgage loans, consisting of $176.9 million of principal repayment, $44.5 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness on the office property located at 2970 Market Street in Philadelphia, Pennsylvania commonly known as 30 th Street Main Post Office (“Cira Square”), ahead of its scheduled maturity date of September 10, 2030. Also on January 14, 2016, the Company funded $44.4 million, consisting of $35.5 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness of a 1,662 parking space facility located in Philadelphia, Pennsylvania commonly known as (“Cira South Garage”), ahead of its scheduled maturity date of September 10, 2030. These repayments were financed with $195.0 million of funds available under the Credit Facility with the remaining balance funded through available cash balances. The Company recognized a $66.6 million loss on extinguishment of debt, consisting of the prepayment charges along with $10.8 million and $2.4 million related to non-cash charges for deferred financing costs for Cira Square and Cira South Garage, respectively. (f) On April 1, 2016, the entire principal balance of the unsecured 6.00% Guaranteed Notes was repaid upon maturity. Available cash balances were used to fund the repayment of the unsecured notes. During 2016, 2015, and 2014, the Company’s weighted-average effective interest rate on its mortgage notes payable was 4.03%, 5.72%, and 5.73%, respectively. As of December 31, 2016 and 2015, the carrying value of the mortgage indebtedness encumbering the Company’s Properties was $325.0 million and $562.7 million, respectively. 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. On September 16, 2014, the Company closed on an underwritten offering of its 4.10% Guaranteed Notes 2024 Notes due October 1, 2024 (the “2014 Notes”) and its 4.55% Guaranteed Notes due October 1, 2029 Notes (the “2029 Notes”). The 2024 Notes were priced at 99.388% of their face amount with a yield to maturity of 4.175%, representing a spread at the time of pricing of 1.70%. The 2029 Notes were priced at 99.191% of their face amount with a yield to maturity of 4.625%, representing a spread at the time of pricing of 2.15%. The 2024 Notes and 2029 Notes have been reflected net of discounts of $1.2 million and $1.7 million, respectively, in the consolidated balance sheets as of December 31, 2016 and $1.3 million and $1.8 million, respectively, in the consolidated balance sheets as of December 31, 2015. The Company used a portion of the net proceeds from the sale of the 2024 Notes and 2029 Notes, aggregating $492.9 million after the deduction for underwriting discounts and offering expenses, to fund its repurchase, through a tender offer, of a portion of the 5.40% Guaranteed Notes due November 1, 2014 (the “2014 Notes”) and 7.50% Guaranteed Notes due May 15, 2015 (the “2015 Notes”). Specifically, on September 16, 2014, the Company funded, under the tender offer, $75.1 million in respect of the 2014 Notes and $42.7 million in respect of the 2015 Notes. The Company recognized a $2.6 million loss on early extinguishment of debt related to the total repurchase during the year ended December 31, 2014. On September 16, 2014, the Company repaid the entire $150.0 million three-year term loan and $100.0 million four-year term loan prior to their scheduled February 2015 and 2016 maturities, respectively. In connection with these repayments, the Company accelerated $0.3 million of deferred financing amortization expense and also incurred a $0.8 million charge on the termination of associated interest rate swap contracts, as reflected in the Company’s consolidated statements of operations. See Note 9, “ Risk Management and Use of Financial Instruments On September 16, 2014, the Company gave notice of redemption, in full, of the $143.5 million in principal amount of 2014 Notes that remained outstanding following completion of the tender offer. The Company completed the redemption of the 2014 Notes on October 16, 2014 at a cash redemption price of $1,026.88 per $1,000 principal amount of the 2014 Notes (inclusive of accrued interest to the redemption date). Also on September 16, 2014, the Company gave notice of redemption, in full, of the $114.9 million in principal amount of 2015 Notes that remained outstanding following completion of the tender offer. The Company completed the redemption of the 2015 Notes on October 16, 2014 at a cash redemption price of $1,070.24 per $1,000 principal amount of the 2015 Notes (inclusive of accrued interest to the redemption date). The Company recognized a $5.0 million loss on early extinguishment of debt related to total repurchase during the year ended December 31, 2014. There were no repurchases of unsecured debt during the twelve months ended December 31, 2016 and 2015. The following table provides additional information on the Company’s repurchase of $376.2 million in aggregate principal amount of its outstanding unsecured notes (consisting of the 2014 Notes and 2015 Notes, as indicated above) during the twelve months ended December 31, 2014 (in thousands): Notes Principal Repurchase Amount (a) Loss on Early Extinguishment of Debt (b) Acceleration of Deferred Financing 2014 5.40% Notes $ 218,549 $ 219,404 $ (855 ) $ 9 2015 7.50% Notes 157,625 164,364 (6,739 ) 143 $ 376,174 $ 383,768 $ (7,594 ) $ 152 (a) Includes cash losses with respect to redemption of debt. (b) Includes unamortized balance of the original issue discount. On October 8, 2015, the Company amended and restated its $200.0 million seven-year term loan maturing February 1, 2019. Pursuant to the terms of the amendment, the Company increased the term loan by an additional $50.0 million, lengthened the maturity date to October 8, 2022, and exercised the option to increase the aggregate amount by up to $150.0 million. The loan bears interest at LIBOR plus 1.80%. Through a series of interest rate swaps, the $250.0 million outstanding balance of the term loan has a fixed interest rate of 3.72%. On May 15, 2015, the Company closed on a four-year unsecured revolving credit facility (the "Credit Facility") that provides for borrowings of up to $600.0 million. The Company expects to use advances under the Credit Facility 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. On terms and conditions specified in the credit agreement, the Company may enter into unsecured term loans and/or increase the initial amount of the credit facility by up to, in the aggregate for all such term loans and increases, an additional $400.0 million. The Credit Facility includes a $65.0 million sub-limit for the issuance of letters of credit and a $60.0 million sub-limit for swing-loans. The Credit Facility has a scheduled maturity date of May 15, 2019, and is subject to two six-month extensions on terms and conditions specified in the credit agreement. At the Company's option, loans outstanding under the Credit Facility will bear interest at a rate per annum equal to (1) LIBOR plus between 0.875% and 1.55% based on the Company's credit rating or (2) a base rate equal to the greatest of (a) the Administrative Agent's prime rate, (b) the Federal Funds rate plus 0.5% or (c) LIBOR for a one month period plus 1.00%, in each case, plus a margin ranging from 0.0% to 0.55% based on the Company's credit rating. The Credit Facility also contains a competitive bid option that allows banks that are part of the lender consortium to bid to make loan advances to the Company at a reduced interest rate. In addition, the Company is also obligated to pay (1) in quarterly installments a facility fee on the total commitment at a rate per annum ranging from 0.125% to 0.30% based on the Company's credit rating and (2) an annual fee on the undrawn amount of each letter or credit equal to the LIBOR Margin. Based on the Company's current credit rating, the LIBOR margin is 1.20% and the facility fee is 0.25%. The Company had no borrowings under the Credit Facility as of December 31, 2016. The Credit Facility contains financial and operating covenants and restrictions, including covenants that relate to the Company’s incurrence of additional debt; granting liens; consummation of mergers and consolidations; the disposition of assets and interests in subsidiaries; the making of loans and investments and the payment of dividends. The terms of the Credit Facility require that the Company maintain customary financial and other covenants, including: (i) a fixed charge coverage ratio greater than or equal to 1.5 to 1.00; (ii) a minimum net worth; (iii) a leverage ratio less than or equal to 0.60 to 1.00, subject to specified exceptions; (iv) a ratio of unsecured indebtedness to unencumbered asset value less than or equal to 0.60 to 1.00, subject to specified exceptions; (v) a ratio of secured indebtedness to total asset value less than or equal to 0.40 to 1.00; and (vi) a ratio of unencumbered cash flow to interest expense on unsecured debt greater than 1.75 to 1.00. In addition, the Credit Facility restricts payments of dividends and distributions on shares in excess of 95% of the Company's funds from operations (FFO) except to the extent necessary to enable the Company to continue to qualify as a REIT for Federal income tax purposes. At December 31, 2016, the Company was in compliance with all covenants in the Credit Facility. Concurrently with its entry into the Credit Facility, the Company terminated its then existing unsecured revolving credit facility, which had a scheduled maturity date of February 1, 2016. The Term Loan contains the same financial and operating covenants and restrictions, including covenants that relate to the Company’s incurrence of additional debt; granting liens; consummation of mergers and consolidations; the disposition of assets and interests in subsidiaries; the making of loans and investments; negative pledges, transactions with affiliates and the payment of dividends, as the Credit Facility. The Company was in compliance with all financial covenants as of December 31, 2016. 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. While the Company currently believes it will remain in compliance with its covenants, in the event that the economy deteriorates in the future, the Company may not be able to remain in compliance with such covenants, in which case a default would result absent a lender waiver. As of December 31, 2016, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2017 $ 304,931 2018 331,601 2019 7,360 2020 86,978 2021 6,099 Thereafter 1,291,679 Total principal payments 2,028,648 Net unamortized premiums/(discounts) (7,439 ) Net deferred financing costs (8,097 ) Outstanding indebtedness $ 2,013,112

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
FAIR VALUE OF FINANCIAL INSTRUMENTS	8. FAIR VALUE OF FINANCIAL INSTRUMENTS The Company determined the fair values disclosed below using available market information and discounted cash flow analyses as of December 31, 2016 and 2015, 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 estimation methodologies may have a material effect on the estimated fair value amounts shown. The Company believes that the carrying amounts reflected in the consolidated balance sheets at December 31, 2016 and 2015 approximate the fair values for cash and cash equivalents, accounts receivable, other assets, 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): December 31, 2016 December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value Unsecured notes payable $ 1,364,854 $ 1,372,758 $ 1,512,554 $ 1,529,346 Variable rate debt $ 326,709 $ 307,510 $ 326,410 $ 305,522 Mortgage notes payable $ 321,549 $ 328,853 $ 545,753 $ 597,377 Note receivable (a) $ 3,380 $ 3,717 $ - $ - (a) The inputs to originate the loan 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. See Note 2, “Significant Accounting Policies,” for further information regarding the note origination. 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 December 31, 2016 and December 31, 2015. 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. For the Company’s mortgage loans, the Company uses an estimate based discounted cash flow analyses and its knowledge of the mortgage market. The weighted average discount rate for the combined variable rate debt and mortgage loans used to calculate fair value as of December 31, 2016 and December 31, 2015 was 4.353% and 4.550%, respectively. 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 December 31, 2016 and December 31, 2015. Although management is not aware of any factors that would significantly affect the fair value amounts, such amounts were not comprehensively revalued for purposes of these financial statements since December 31, 2016. Current estimates of fair value may differ from the amounts presented herein.

Risk Management and Use of Deri

Risk Management and Use of Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2016
Derivative Instruments And Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND USE OF DERIVATIVE FINANCIAL INSTRUMENTS	9. RISK MANAGEMENT AND USE OF DERIVATIVE FINANCIAL INSTRUMENTS Risk Management In the course of its ongoing business operations, the Company encounters economic risk. There are three main components of economic risk: interest rate risk, credit risk and market risk. The Company is subject to interest rate risk on its interest-bearing liabilities. Credit risk is primarily the risk of inability or unwillingness of tenants to make contractually required payments and of counterparties on derivatives contracts to fulfill their obligations. Market risk is the risk of declines in the value of Company properties due to changes in rental rates, interest rates, supply and demand of similar products and other market factors affecting the valuation of properties. Risks and Uncertainties In the U.S., market and economic conditions have been improving, resulting in an increase of the volume of real estate transactions in the market. If the economy deteriorates, vacancy rates may increase through 2017 and possibly beyond. The financial markets also have an effect on the Company’s Real Estate Venture partners and contractual counterparties, including counterparties in derivative contracts. The Company’s Credit Facility, term loans and the indenture governing its unsecured public debt securities (See Note 7, “ Debt Obligations Availability of borrowings under the unsecured revolving credit facility is subject to a traditional material adverse effect clause. Each time the Company borrows it must represent to the lenders that there have been no events of a nature which would have a material adverse effect on the business, assets, operations, condition (financial or otherwise) or prospects of the Company taken as a whole or which could negatively affect the ability of the Company to perform its obligations under the unsecured revolving credit facility. While the Company believes that there are currently no material adverse effect events, it is possible that such an event could arise which would limit the Company’s borrowings under the unsecured revolving credit facility. If an event occurs which is considered to have a material adverse effect, the lenders could consider the Company in default under the terms of the unsecured revolving credit facility and any borrowings under the unsecured revolving credit facility would become unavailable. If the Company is unable to obtain a waiver, this would have a material adverse effect on the Company’s financial position and results of operations. The Company was in compliance with all financial covenants as of December 31, 2016. Management continuously monitors the Company’s compliance with and anticipated compliance with the covenants. Certain of the covenants restrict management’s ability to obtain alternative sources of capital. While the Company currently believes it will remain in compliance with its covenants, in the event that the economy deteriorates in the future, the Company may not be able to remain in compliance with such covenants, in which case a default would result absent a lender waiver. Use of Derivative Financial Instruments The Company’s use of derivative instruments is limited to the utilization of interest rate agreements or other instruments to manage interest rate risk exposures and not for speculative purposes. The principal objective of such arrangements is to minimize the risks and/or costs associated with the Company’s operating and financial structure, as well as to hedge specific transactions. The counterparties to these arrangements are major financial institutions with which the Company and its affiliates may also have other financial relationships. The Company is potentially exposed to credit loss in the event of non-performance by these counterparties. However, because of the high credit ratings of the counterparties, the Company does not anticipate that any of the counterparties will fail to meet these obligations as they come due. The Company does not hedge credit or property value market risks through derivative financial instruments. The Company formally assesses, both at inception of a hedge and on an on-going basis, whether each derivative is highly-effective in offsetting changes in cash flows of the hedged item. If management determines that a derivative is not highly-effective as a hedge or if a derivative ceases to be a highly-effective hedge, the Company will discontinue hedge accounting prospectively for either the entire hedge or the portion of the hedge that is determined to be ineffective. The related ineffectiveness would be charged to the consolidated statement of operations. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. To comply with the provisions of the accounting standard for fair value measurements and disclosures, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. The following table summarizes the terms and fair values of the Company’s derivative financial instruments as of December 31, 2016 and December 31, 2015. 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 liabilities on the Company’s consolidated balance sheets). Hedge Product Hedge Type Designation Notional Amount Strike Trade Date Maturity Date Fair value 12/31/2016 12/31/2015 12/31/2016 12/31/2015 Assets Swap Interest Rate Cash Flow (a) $ 250,000 $ 250,000 3.718 % October 8, 2015 October 8, 2022 $ 3,733 $ 1,884 Liabilities Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 (300 ) (531 ) Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 (214 ) (388 ) Swap Interest Rate Cash Flow (a) 27,062 27,062 2.750 % December 21, 2011 September 30, 2017 (83 ) (201 ) $ 328,610 $ 328,610 (a) Hedging unsecured variable rate debt. The Company measures its derivative instruments at fair value and records them in the balance sheet as either an asset or liability. As of December 31, 2016, one interest rate swap held an asset position and is included in other assets on the Company’s consolidated balance sheet. The remaining swaps are included in other liabilities on the Company’s consolidated balance sheet. 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. Disclosure about the fair value of derivative instruments is based upon pertinent information available to management as of December 31, 2016 and December 31, 2015. 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 December 31, 2016. Current estimates of fair value may differ from the amounts presented herein. Concentration of Credit Risk Concentrations of credit risk arise for the Company when multiple tenants of the Company are engaged in similar business activities, or are located in the same geographic region, or have similar economic features that impact in a similar manner their ability to meet contractual obligations, including those to the Company. The Company regularly monitors its tenant base to assess potential concentrations of credit risk. Management believes the current credit risk portfolio is reasonably well diversified and does not contain an unusual concentration of credit risk. No tenant accounted for 10% or more of the Company’s rents during 2016, 2015 and 2014. Conditions in the general economy and the global credit markets have had a significant adverse effect on numerous industries. The Company has tenants concentrated in various industries that may be experiencing adverse effects from the current economic conditions and the Company could be adversely affected if such tenants were to default under their leases.

Discontinued Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2016
Discontinued Operations And Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	10. DISCONTINUED OPERATIONS The Company had no property dispositions classified as discontinued operations during the years ended December 31, 2016 and 2015. There was nominal income before gain on sales recognized during 2014 relating to properties classified into discontinued operations in prior periods and a $0.9 million gain relating to the post closing activity for the sale of the Princeton Pike Corporate Center in Lawrenceville, New Jersey completed in the first quarter of 2013. For the year ended December 31, 2014, income from discontinued operations relates to post closing activity stemming from the disposition of an aggregate of 14 properties containing approximately 1.1 million net rentable square feet that the Company sold during the first quarter of 2013. The following table summarizes revenue and expense information for the properties sold which qualify for discontinued operations reporting since January 1, 2014 (in thousands): Years ended December 31, 2014 Revenue: Rents $ - Tenant reimbursements 26 Other - Total revenue 26 Expenses: Property operating expenses 8 Real estate taxes - Depreciation and amortization - Total operating expenses 8 Other income: Interest income - Income from discontinued operations before gain on sale of interests in real estate 18 Net gain on disposition of discontinued operations 900 Income from discontinued operations $ 918 Discontinued operations have not been segregated in the consolidated statements of cash flows. Therefore, amounts for certain captions will not agree with respective data in the consolidated statements of operations.

Limited Partners' Non-Controlli

Limited Partners' Non-Controlling Interests in the Parent Company	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
LIMITED PARTNERS' NON-CONTROLLING INTERESTS IN THE PARENT COMPANY	11. 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 that were consolidated in the accompanying consolidated balance sheet of the Parent Company as of December 31, 2016 and December 31, 2015, was $14.9 million and $16.1 million, 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 date) was approximately $24.4 million and $21.0 million, respectively, as of December 31, 2016 and December 31, 2015.

Beneficiaries Equity of the Par

Beneficiaries Equity of the Parent Company	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
BENEFICIARIES' EQUITY OF THE PARENT COMPANY	12. 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): Year ended December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ 40,501 $ 40,501 $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 Net (income) loss from continuing operations attributable to non-controlling interests (310 ) (310 ) 339 339 43 43 Nonforfeitable dividends allocated to unvested restricted shareholders (341 ) (341 ) (329 ) (329 ) (349 ) (349 ) Preferred share dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Income (loss) from continuing operations available to common shareholders 32,950 32,950 (37,630 ) (37,630 ) (1,182 ) (1,182 ) Income from discontinued operations - - - - 908 908 Net income (loss) attributable to common shareholders $ 32,950 $ 32,950 $ (37,630 ) $ (37,630 ) $ (274 ) $ (274 ) Denominator Weighted-average shares outstanding 175,018,163 175,018,163 178,162,160 178,162,160 166,202,649 166,202,649 Contingent securities/Share based compensation - 992,651 - - - - Weighted-average shares outstanding 175,018,163 176,010,814 178,162,160 178,162,160 166,202,649 166,202,649 Earnings (loss) per Common Share: Income (loss) from continuing operations attributable to common shareholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ (0.01 ) $ (0.01 ) Discontinued operations attributable to common shareholders - - - - 0.01 0.01 Net income (loss) attributable to common shareholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ - $ - The contingent securities/share based compensation impact is calculated using the treasury stock method and relates to employee awards settled in shares of the Parent Company. The effect of these securities is anti-dilutive for periods that the Parent Company incurs a net loss from continuing operations available to common shareholders and therefore is excluded from the dilutive earnings per share calculation in such periods. Redeemable common limited partnership units, totaling 1,479,799 in 2016 and 1,535,102 in both 2015 and 2014, 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 years ended December 31, 2016, 2015 and 2014, earnings representing nonforfeitable dividends were allocated to the unvested restricted shares issued to the Company’s executives and other employees under the Amended and Restated 1997 Long-Term Incentive Plan. Common and Preferred Shares On December 6, 2016, the Parent Company declared a distribution of $0.16 per common share, totaling $28.1 million, which was paid on January 25, 2017 to shareholders of record as of January 11, 2017. On December 6, 2016, the Parent Company declared distributions on its Series E Preferred Shares to holders of record as of December 30, 2016. These shares are entitled to a preferential return of 6.90% per annum on the $25.00 per share liquidation preference. Distributions paid on January 17, 2017 to holders of Series E Preferred Shares totaled $1.7 million. Common Share Repurchases The Parent Company maintains a common share repurchase program under which the Board of Trustees has authorized the Parent Company to repurchase common shares with no expiration date. On July 22, 2015, the Parent Company's Board of Trustees authorized additional common share repurchases of up to $100.0 million. Prior to the authorization, 539,200 common shares were available for repurchase under the preexisting share repurchase program. The Company expects to fund the share repurchases with a combination of available cash balances and availability under its unsecured revolving credit facility. During the year ended December 31, 2016, there were no share repurchases under the program. During the year ended December 31, 2015, the Company repurchased and retired 5,209,437 common shares at an average purchase price of $12.90 per share and totaling $67.3 million. All of the repurchases under the current common share repurchase program occurred during 2015. The timing and amounts of any purchases will depend on a variety of factors, including market conditions, regulatory requirements, share prices, capital availability and other factors as determined by the Company’s management team. The repurchase program does not require the purchase of any minimum number of shares and may be suspended or discontinued at any time without notice. The common shares repurchased were retired and, as a result, were accounted for in accordance with Maryland law, which does not contemplate treasury stock. The repurchases were recorded as a reduction of common share (at $0.01 par value per share) and a decrease to additional paid-in-capital.

Partners Equity of The Operatin

Partners Equity of The Operating Partnership	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
PARTNERS' EQUITY OF THE OPERATING PARTNERSHIP	13. 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): Year ended December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ 40,501 $ 40,501 $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 Nonforfeitable dividends allocated to unvested restricted unitholders (341 ) (341 ) (329 ) (329 ) (349 ) (349 ) Preferred unit dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Net (income) loss attributable to non-controlling interests (15 ) (15 ) 3 3 44 44 Income (loss) from continuing operations available to common unitholders 33,245 33,245 (37,966 ) (37,966 ) (1,181 ) (1,181 ) Discontinued operations attributable to common unitholders - - - - 918 918 Net income (loss) attributable to common unitholders $ 33,245 $ 33,245 $ (37,966 ) $ (37,966 ) $ (263 ) $ (263 ) Denominator Weighted-average units outstanding 176,523,800 176,523,800 179,697,262 179,697,262 167,942,246 167,942,246 Contingent securities/Share based compensation - 992,651 - - - - Total weighted-average units outstanding 176,523,800 177,516,451 179,697,262 179,697,262 167,942,246 167,942,246 Earnings (loss) per Common Partnership Unit: Income (loss) from continuing operations attributable to common unitholders 0.19 0.19 (0.21 ) (0.21 ) (0.01 ) (0.01 ) Discontinued operations attributable to common unitholders - - - - 0.01 0.01 Net income (loss) attributable to common unitholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ - $ - 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 unit. For the years ended December 31, 2016, 2015 and 2014, earnings representing nonforfeitable dividends were allocated to the unvested restricted units issued to the Parent Company’s executives and other employees under the Parent Company’s shareholder-approved long-term incentive plan. Common Partnership Units and Preferred Mirror Units The Operating Partnership issues partnership units to the Parent Company in exchange for the contribution of the net proceeds of any equity security issuance by the Parent Company. The number and terms of such partnership units correspond to the number and terms of the related equity securities issued by the Parent Company. In addition, the Operating Partnership may also issue separate classes of partnership units. Historically, the Operating Partnership has had the following types of partnership units outstanding: (i) Preferred Partnership Units which have been issued to parties other than the Parent Company; (ii) Preferred Mirror Partnership Units which have been issued to the Parent Company; and (iii) Common Partnership Units which include both interests held by the Parent Company and those held by other limited partners. Preferred Mirror Partnership Units In exchange for the proceeds received in corresponding offerings by the Parent Company of preferred units of beneficial interest, the Operating Partnership has issued to the Parent Company a corresponding amount of Preferred Mirror Partnership Units with terms consistent with that of the preferred securities issued by the Parent Company. Common Partnership Units (Redeemable and General) The Operating Partnership has two classes of Common Partnership Units: (i) Class A Limited Partnership Interest which are held by both the Parent Company and outside third parties and (ii) General Partnership Interests which are held by the Parent Company (collectively, the Class A Limited Partnership Interest, and General Partnership Interests are referred to as “Common Partnership Units”). The holders of the Common Partnership Units are entitled to share in cash distributions from, and in profits and losses of, the Operating Partnership, in proportion to their respective percentage interests, subject to preferential distributions on the preferred mirror units and the preferred units. The Common Partnership Units held by the Parent Company (comprised of both General Partnership Units and Class A Limited Partnership Units) are presented as partner’s equity in the consolidated financial statements. Class A Limited Partnership Interest held by parties other than the Parent Company are redeemable at the option of the holder for a like number of common shares of the Parent Company, or cash, or a combination thereof, at the election of the Parent Company. Because the form of settlement of these redemption rights are not within the control of the Operating Partnership, these Common Partnership Units have been excluded from partner’s equity and are presented as redeemable limited partnership units measured at the potential cash redemption value as of the end of the periods presented based on the closing market price of the Parent Company’s common shares at December 31, 2016, 2015 and 2014, which was $16.51, $13.66, $15.98, respectively. As of December 31, 2016, 1,479,799 of Class A Units were outstanding and owned by outside limited partners of the Operating Partnership. As of both December 31, 2015 and 2014, 1,535,102 of Class A Units were outstanding and owned by outside limited partners of the Operating Partnership. On December 6, 2016, the Operating Partnership declared a distribution of $0.16 per common unit, totaling $28.1 million, which was paid on January 25, 2017 to unitholders of record as of January 11, 2017. On December 6, 2016, the Operating Partnership declared distributions on its Series E Preferred Units to holders of record as of December 30, 2016. These units are entitled to a preferential return of 6.90% per annum on the $25.00 per share liquidation preference. Distributions paid on January 17, 2017 to holders of Series E Preferred Shares totaled $1.7 million. Common Unit Repurchases In connection with the Parent Company’s repurchase program, one mirror unit is retired for each common share repurchased. The Board of Trustees has authorized the Parent Company to repurchase common units with no expiration date. On July 22, 2015, the Parent Company's Board of Trustees authorized additional common unit repurchases of up to $100.0 million. Prior to the authorization, 539,200 common units were available for repurchase under the preexisting unit repurchase program. The Company expects to fund the unit repurchases with a combination of available cash balances and availability under its unsecured revolving credit facility. During the year ended December 31, 2016, there were no unit repurchases under the program. During the year ended December 31, 2015, the Company repurchased and retired 5,209,437 common units at an average purchase price of $12.90 per unit and totaling $67.3 million. All of the repurchases under the current common unit repurchase program occurred during 2015. . The common shares repurchased were retired and, as a result, were accounted for in accordance with Maryland law, which does not contemplate treasury stock. The repurchases were recorded as a reduction of common shares (at $0.01 par value per share) and a decrease to additional paid-in-capital.

Share Based Compensation, 401(k

Share Based Compensation, 401(k) Plan and Deferred Compensation	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
SHARE BASED COMPENSATION, 401(k) PLAN AND DEFERRED COMPENSATION	14. SHARE BASED COMPENSATION, 401(k) PLAN AND DEFERRED COMPENSATION Stock Options At December 31, 2016, options exercisable for 2,377,778 common shares were outstanding under the Parent Company’s shareholder approved equity incentive plan (referred to as the “Equity Incentive Plan”). During the years ended December 31, 2016 and 2015, the Company did not recognize any compensation expense related to unvested options. For the year ended 2014, the Company recognized compensation expense related to unvested options that was nominal. During both the years ended December 31, 2016 and 2015, the Company did not capitalize any compensation expense related to stock options as part of the Company’s review of employee salaries eligible for capitalization. For the year ended December 31, 2014, the Company capitalized a nominal amount. Option activity as of December 31, 2016 and changes during the year-ended December 31, 2016 were as follows: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2016 2,624,067 $ 15.47 3.12 Exercised (111,209 ) $ 11.56 $ 347,881 Forfeited/Expired (135,080 ) $ 20.61 Outstanding at December 31, 2016 2,377,778 $ 15.36 2.15 $ 8,003,403 Vested/Exercisable at December 31, 2016 2,377,778 $ 15.36 2.15 $ 8,003,403 401(k) Plan The Company sponsors a 401(k) defined contribution plan for its employees. Each employee may contribute up to 100% of annual compensation, subject to specific limitations under the Internal Revenue Code. At its discretion, the Company can make matching contributions equal to a percentage of the employee’s elective contribution and profit sharing contributions. The Company funds its 401(k) contributions annually and plan participants must be employed as of December 31 st Restricted Share Awards As of December 31, 2016, 488,604 restricted shares were outstanding under the Equity Incentive Plan and vest over three years from the initial grant dates. The remaining compensation expense to be recognized at December 31, 2016 was approximately $2.1 million, and is expected to be recognized over a weighted average remaining vesting period of 1.4 years. During 2016, the Company recognized compensation expense related to outstanding restricted shares of $2.6 million, of which $0.4 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. For the years ended December 31, 2015 and 2014, the Company recognized $2.4 million (of which $0.7 million was capitalized) and $2.7 million (of which $0.6 million was capitalized), respectively, of compensation expense included in general and administrative expense in the respective periods related to outstanding restricted shares. The following table summarizes the Company’s restricted share activity during the year-ended December 31, 2016: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2016 506,147 $ 14.50 $ 6,913,968 Granted 227,845 12.92 2,937,771 Vested (195,140 ) 13.50 2,813,799 Forfeited (50,248 ) 15.03 Non-vested at December 31, 2016 488,604 $ 14.10 $ 8,066,852 On February 22, 2016, the Compensation Committee of the Parent Company’s Board of Trustees awarded to officers of the Company an aggregate 141,358 restricted common shares, which cliff vest on April 15, 2019. On March 8, 2016, the Compensation Committee awarded non-officer employees an aggregate 54,168 restricted common shares, which vest in three equal annual installments on April 15 of 2017, 2018 and 2019. In addition, on May 24, 2016, the Compensation Committee awarded 32,319 restricted shares which vest ratably over three years from the date of grant. Vesting of restricted common shares is subject to acceleration upon certain events, including if the recipient of the award were to die, become disabled or, in certain cases, retire in a qualifying retirement. 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, in the case of the Company’s President and Chief Executive Officer, vesting would also accelerate if the Company were to terminate him without cause, or if he were to resign for good reason under his employment agreement. In addition, if the Company were to undergo a change of control, then unvested shares would also accelerate if, in connection with the change of control or within a specified period after the change of control, the holder’s employment were to terminate in a qualifying termination or resignation. 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 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 3/11/2014 3/12/2014 2/23/2015 2/22/2016 Total (Amounts below in shares, unless otherwise noted) Non-vested at January 1, 2016 123,155 61,720 179,392 - 364,267 Units Granted - - - 231,388 231,388 Units Cancelled (30,724 ) - (31,803 ) - (62,527 ) Non-vested at December 31, 2016 92,431 61,720 147,589 231,388 533,128 Measurement Period Commencement Date 1/1/2014 1/1/2014 1/1/2015 1/1/2016 Measurement Period End Date 12/31/2016 12/31/2016 12/31/2017 12/31/2018 Units Granted 134,284 61,720 186,395 231,388 Fair Value of Units on Grant Date (in thousands) $ 2,624 $ 1,255 $ 3,933 $ 3,558 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 year ended December 31, 2016, the Company recognized total compensation expense for the 2016, 2015 and 2014 RPSU awards of $2.8 million, of which $0.6 million was capitalized consistent with the Company’s policies for capitalizing eligible portions of employee compensation. For the year ended December 31, 2015, the Company recognized total compensation expense for the 2015, 2014 and 2013 RPSU awards of $4.2 million, of which $1.2 million was capitalized consistent with the Company’s policies for capitalizing eligible portions of employee compensation. For the year ended December 31, 2014, the Company recognized total compensation expense for the 2014, 2013 and 2012 RPSU awards of $3.2 million, of which $1.1 million was capitalized consistent with the Company’s policies for capitalizing eligible portions of employee compensation. The remaining compensation expense to be recognized at December 31, 2016 was approximately $1.5 million, and is expected to be recognized over a weighted average remaining vesting period of 1.2 years. The Company issued 156,415 common shares on February 1, 2016 in settlement of RPSUs that had been awarded on February 23, 2013 (with a three-year measurement period ended December 31, 2015). Holders of these RPSUs also received a cash dividend of $0.15 per share for these common shares on February 5, 2016. Employee Share Purchase Plan The Parent Company’s shareholders approved the 2007 Non-Qualified Employee Share Purchase Plan (the “ESPP”), which is intended to provide eligible employees with a convenient means to purchase common shares of the Parent Company through payroll deductions and voluntary cash purchases at an amount equal to 85% of the average closing price per share for a specified period. Under the plan document, the maximum participant contribution for the 2016 plan year is limited to the lesser of 20% of compensation or $50,000. The ESPP allows the Parent Company to make open market purchases, which reflects all purchases made under the plan to date. In addition, the number of shares separately reserved for issuance under the ESPP is 1.25 million. During the year ended December 31, 2016, employees made purchases under the ESPP of $0.4 million and the Company recognized $0.2 million of compensation expense related to the ESPP. During the years ended December 31, 2015 and 2014, employees made purchases under the ESPP of $0.5 million and $0.4 million, respectively, and the Company recognized $0.1 million of compensation expense related to the ESPP for both years. Compensation expense represents the 15% discount on the purchase price. The Board of Trustees of the Parent Company may terminate the ESPP at its sole discretion at any time. Deferred Compensation In January 2005, the Parent Company adopted a Deferred Compensation Plan (the “Plan”) that allows trustees and certain key employees to voluntarily defer compensation. Compensation expense is recorded for the deferred compensation and a related liability is recognized. Participants may elect designated benchmark investment options for the notional investment of their deferred compensation. The deferred compensation obligation is adjusted for deemed income or loss related to the investments selected. At the time the participants defer compensation, the Company records a liability, which is included in the Company’s consolidated balance sheet. The liability is adjusted for changes in the market value of the participant-selected investments at the end of each accounting period, and the impact of adjusting the liability is recorded as an increase or decrease to compensation cost. The Company has purchased mutual funds which can be utilized as a funding source for the Company’s obligations under the Plan. Participants in the Plan have no interest in any assets set aside by the Company to meet its obligations under the Plan. For each of the years ended December 31, 2016, December 31, 2015 and December 31, 2014, the Company recorded a nominal amount of deferred compensation costs, net of investments in the company-owned policies and mutual funds. Participants in the Plan may elect to have all or a portion of their deferred compensation invested in the Company’s common shares. The Company holds these shares in a rabbi trust, which is subject to the claims of the Company’s creditors in the event of the Company’s bankruptcy or insolvency. The Plan does not permit diversification of a participant’s deferral allocated to the Company common shares and deferrals allocated to Company common shares can only be settled with a fixed number of shares. In accordance with the accounting standard for deferred compensation arrangements where amounts earned are held in a rabbi trust and invested, the deferred compensation obligation associated with the Company’s common shares is classified as a component of shareholder’s equity and the related shares are treated as shares to be issued and are included in total shares outstanding. At December 31, 2016 and 2015, 0.8 million and 0.7 million of such shares, respectively, were included in total shares outstanding. Subsequent changes in the fair value of the common shares are not reflected in operations or shareholders’ equity of the Company.

Distributions

Distributions	12 Months Ended
	Dec. 31, 2016
Distributions [Abstract]
DISTRIBUTIONS	15. DISTRIBUTIONS The following table provides the tax characteristics of the 2016, 2015 and 2014 distributions paid: Years ended December 31, 2016 2015 2014 (in thousands, except per share amounts) Common Share Distributions: Ordinary income $ - $ 0.36 $ 0.41 Capital gain 0.62 0.14 0.02 Non-taxable distributions - 0.10 0.17 Distributions per share $ 0.62 $ 0.60 $ 0.60 Percentage classified as ordinary income 0.00 % 59.10 % 69.00 % Percentage classified as capital gain 100.00 % 23.50 % 3.30 % Percentage classified as non-taxable distribution 0.00 % 17.40 % 27.70 % Preferred Share Distributions: Total distributions paid $ 6,900 $ 6,900 $ 6,900 Percentage classified as ordinary income 100.00 % 100.00 % 100.00 %

Tax Credit Transactions

Tax Credit Transactions	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
TAX CREDIT TRANSACTIONS	16. TAX CREDIT TRANSACTIONS Historic Tax Credit Transaction On November 17, 2008, the Company closed a transaction with US Bancorp (“USB”) related to the historic rehabilitation of the IRS Philadelphia Campus, a 862,692 square foot office building that is 100% leased to the IRS. On August 27, 2010, the Company completed the development of the IRS Philadelphia Campus and the IRS lease commenced. In connection with this completed development project, USB contributed to the Company $64.1 million of total project costs. In exchange for its contributions to the development of the IRS Philadelphia Campus, USB was entitled to substantially all of the benefits derived from the tax rehabilitation credits available under section 47 of the Internal Revenue Code. USB did not have a material interest in the underlying economics of the property. This transaction included a put/call provision whereby the Company was obligated or entitled to repurchase USB’s interest in the IRS Philadelphia Campus. The put option was exercised on September 30, 2015 and USB's interest in the IRS Philadelphia Campus was assigned to the Company. A purchase price of $3.2 million was attributed to that puttable non-controlling interest obligation, which was funded with available corporate funds. Upon exercise of the put option, the Company funded USB's final 2% preferred return of $1.0 million. Based on the contractual arrangements that obligated the Company to deliver tax benefits and provide other guarantees to USB and that entitled the Company through fee arrangements to receive substantially all available cash flow from the IRS Philadelphia Campus, the Company concluded that the IRS Philadelphia Campus should be consolidated. The Company also concluded that capital contributions received from USB, in substance, were consideration that the Company received in exchange for its obligation to deliver tax credits and other tax benefits to USB. These receipts other than the amounts allocated to the put obligation were recognized as revenue in the consolidated financial statements beginning when the obligation to USB was relieved which occurred upon delivery of the expected tax benefits net of any associated costs. The tax credit is subject to 20% recapture per year beginning one year after the completion of the IRS Philadelphia Campus. Beginning September 2011 to September 2015, the Company recognized the cash received as revenue net of allocated expenses over the five year credit recapture period as defined in the Internal Revenue Code within other income (expense) in its consolidated statement of operations. The fifth and final recapture period ended September 30, 2015 and the Company recognized $11.9 million of cash received as revenue, net of $0.5 million of allocated expenses within other income (expense) it its consolidated statement of operations. As of December 31, 2016 and 2015, there were no USB contributions presented in the Company’s balance sheet Direct and incremental costs incurred in structuring the transaction were deferred and were recognized as expense in the consolidated financial statements upon the recognition of the related revenue as discussed above. There were no deferred costs at December 31, 2016 and 2015. Amounts included in interest expense related to the accretion of the non-controlling interest liability and the 2% return expected to be paid to USB on its non-controlling interest aggregates to $1.1 million for the year ended December 31, 2015. There was no interest accretion for the year ended December 31, 2016. New Markets Tax Credit Transaction On December 30, 2008, the Company entered into a transaction with USB related to the Cira South Garage in Philadelphia, Pennsylvania and received a net benefit of $8.0 million under a qualified New Markets Tax Credit Program (“NMTC”). The NMTC was provided for in the Community Renewal Tax Relief Act of 2000 (the “Act”) and is intended to induce investment capital in under-served and impoverished areas of the United States. The Act permits taxpayers (whether companies or individuals) to claim credits against their Federal income taxes for up to 39% of qualified investments in qualified, active low-income businesses or ventures. USB contributed $13.3 million into the development of the Cira South Garage and as such it is entitled to substantially all of the benefits derived from the tax credit, but it does not have a material interest in the underlying economics of the Cira South Garage. This transaction also includes a put/call provision whereby the Company may be obligated or entitled to repurchase USB’s interest. The Company believes the put will be exercised and an amount attributed to that obligation is included in other liabilities and is being accreted to the expected fixed put price. The said put price is insignificant. Based on the contractual arrangements that obligate the Company to deliver tax benefits and provide various other guarantees to USB, the Company concluded that the investment entities established to facilitate the NMTC transaction should be consolidated. There were no USB contributions presented in the Company's balance sheet at December 31, 2016 and 2015. The USB contribution other than the amount allocated to the put obligation was recognized as income in the consolidated financial statements when the tax benefits were delivered on December 30, 2015 without risk of recapture to the tax credit investors and the Company’s obligation is relieved. The NMTC is subject to 100% recapture for a period of seven years from the date that construction of the Cira South Garage commenced as provided in the Internal Revenue Code. The Company recognized the $8.1 million of net cash received as revenue within tax credit transaction income in the year ended December 31, 2015. The Company expects that the put/call provision will be exercised in 2017.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss)	17. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The following table details the components of accumulated other comprehensive income (loss) of the Parent Company and the Operating Partnership as of and for the three years ended December 31, 2016 (in thousands): Parent Company Cash Flow Hedges Balance at January 1, 2014 $ (2,995 ) Change during year (1,190 ) Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests 18 Settlement of interest rate swaps (828 ) Reclassification adjustments for (gains)/losses reclassified into operations 388 Balance at December 31, 2014 $ (4,607 ) Change during year (1,010 ) Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests 5 Reclassification adjustments for (gains)/losses reclassified into operations 420 Balance at December 31, 2015 $ (5,192 ) Change during year 2,371 Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests (28 ) Reclassification adjustments for (gains)/losses reclassified into operations 1,104 Balance at December 31, 2016 $ (1,745 ) Operating Partnership Cash Flow Hedges Balance at January 1, 2014 $ (3,377 ) Change during year (1,190 ) Settlement of interest rate swaps (828 ) Reclassification adjustments for (gains)/losses reclassified into operations 388 Balance at December 31, 2014 $ (5,007 ) Change during year (1,010 ) Reclassification adjustments for (gains)/losses reclassified into operations 420 Balance at December 31, 2015 $ (5,597 ) Change during year 2,371 Reclassification adjustments for (gains)/losses reclassified into operations 1,104 Balance at December 31, 2016 $ (2,122 ) Over time, the unrealized gains and losses held in Accumulated Other Comprehensive Income (“AOCI”) will be reclassified to interest expense when the related hedged items are recognized in earnings. The current balance held in AOCI is expected to be reclassified to interest expense for realized losses on forecasted debt transactions over the related term of the debt obligation, as applicable. The Company expects to reclassify $1.2 million from AOCI into interest expense within the next twelve months.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
SEGMENT INFORMATION	18. SEGMENT INFORMATION During the year ended December 31, 2015, the Company managed its portfolio within seven segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (CBD), (3) Metropolitan Washington, D.C., (4) New Jersey/Delaware, (5) Richmond, Virginia, (6) Austin, Texas and (7) California. As a result of the Och-Ziff Sale that occurred on February 4, 2016, the Company has narrowed its segments to five segments located in: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C. and (4) Austin, Texas. The Och-Ziff Sale disposed of the entire Richmond, Virginia segment. Subsequent to the Och-Ziff Sale, the segments previously defined as New Jersey/Delaware and California are now being managed as a consolidated segment entitled (5) “Other,” as these geographies no longer provide a significant revenue contribution. The Pennsylvania Suburbs segment includes properties in Chester, Delaware, and Montgomery counties in the Philadelphia suburbs. The Philadelphia CBD segment includes properties located in the City of Philadelphia in Pennsylvania. 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 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 are 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 for the three years ended December 31, 2016, 2015 and 2014 (in thousands): Real estate investments, at cost: December 31, 2016 December 31, 2015 December 31, 2014 Philadelphia CBD $ 1,320,974 $ 1,157,667 $ 1,338,655 Pennsylvania Suburbs 1,005,446 1,019,280 1,178,470 Metropolitan Washington, D.C. 975,987 1,129,206 1,183,652 Austin, Texas 146,794 164,518 - Other (a) 137,094 222,329 902,915 $ 3,586,295 $ 3,693,000 $ 4,603,692 Assets held for sale (b), (c) 73,591 794,588 27,436 Operating Properties $ 3,659,886 $ 4,487,588 $ 4,631,128 Corporate Construction-in-progress $ 297,462 $ 268,983 $ 201,360 Land inventory $ 150,970 $ 130,479 $ 90,603 (a) As a result of the Och-Ziff Sale that occurred on February 4, 2016, the Company narrowed its segments to five segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C. and (4) Austin, Texas and (5) Other. The Och-Ziff Sale disposed of the entire Richmond, Virginia segment. Subsequent to the Och-Ziff Sale, the segments previously defined as New Jersey/Delaware and California are now being managed as a consolidated segment entitled “Other,” as these geographies no longer provide a significant revenue contribution. Accordingly, the chief operating decision maker revised the management structure, reallocated resources, and is assessing business operations of the five segments as of January 1, 2016. (b) As of December 31, 2015, 2970 Market Street was classified as held for sale on the consolidated balance sheets. The property was sold on February 5, 2016. See Note 21, " Subsequent Events ," for further information. The sale is not classified as a significant disposition under the accounting guidance for discontinued operations. (c) As of December 31, 2015, the 58 properties associated with the series of related transactions with Och-Ziff Real Estate were classified as held for sale on the consolidated balance sheets. On February 4, 2016, the Company completed a series of transactions, resulting in the disposition of the properties. See Note 3, “Real Estate Investments,” for further information regarding the disposition. Additionally, as of December 31, 2016, the Company categorized three office properties located in the Metropolitan Washington, D.C. segment and two properties in the Other segment as held for sale in accordance with applicable accounting standards for long lived assets. See Note 3, “Real Estate Investments,” for further information. None of the above aforementioned sales or properties classified as held for sale are considered significant dispositions under the accounting guidance for discontinued operations. Years ended December 31, 2016 2015 2014 Total revenue Operating expenses (a) Net operating income Total revenue Operating expenses (a) Net operating income Total revenue Operating expenses (a) Net Operating income Philadelphia CBD $ 200,245 $ (78,708 ) $ 121,537 $ 209,298 $ (77,352 ) $ 131,946 $ 201,809 $ (75,262 ) $ 126,547 Pennsylvania Suburbs 144,338 (49,208 ) 95,130 158,398 (57,319 ) 101,079 160,630 (55,062 ) 105,568 Metropolitan Washington, D.C. 99,781 (39,036 ) 60,745 110,657 (44,294 ) 66,363 113,834 (43,399 ) 70,435 Austin, Texas (b) 34,585 (13,222 ) 21,363 20,910 (8,010 ) 12,900 5,610 (3,223 ) 2,387 Other 39,359 (23,204 ) 16,155 98,799 (49,604 ) 49,195 113,971 (57,214 ) 56,757 Corporate 7,155 (6,070 ) 1,085 4,569 (1,508 ) 3,061 1,128 (1,805 ) (677 ) Operating Properties $ 525,463 $ (209,448 ) $ 316,015 $ 602,631 $ (238,087 ) $ 364,544 $ 596,982 $ (235,965 ) $ 361,017 (a) Includes property operating expense, real estate taxes and third party management expense. (b) On June 22, 2015 the Company acquired the remaining 50.0% of the common interest in Broadmoor Austin Associates. As such, the Company has seven wholly owned properties in its Austin, Texas business segment at December 31, 2016. In addition, net operating income for the years ended December 31, 2016 and 2015 includes management fees and related expenses for services provided by the Company to the Austin Venture. "Real Estate Investments," Unconsolidated real estate ventures: Investment in real estate ventures, at equity Equity in income (loss) of real estate ventures As of Years ended December 31, December 31, 2016 December 31, 2015 December 31, 2014 2016 2015 2014 Philadelphia CBD $ 48,691 $ 44,089 $ 27,137 $ (686 ) $ (188 ) $ 46 Pennsylvania Suburbs 15,421 16,408 17,385 748 310 (777 ) Metropolitan Washington, D.C. (a) 141,786 118,422 73,127 (6,293 ) (336 ) (317 ) MAP Venture (b) 20,893 - - (4,218 ) - - Other (c) 1,654 1,657 1,574 814 930 1,338 Austin, Texas (d) 52,886 60,428 105,781 (1,868 ) (1,527 ) (1,080 ) Total $ 281,331 $ 241,004 $ 225,004 $ (11,503 ) $ (811 ) $ (790 ) (a) On August 31, 2016, the Company terminated its lease for the regional management and leasing office at 3141 Fairview Park Drive, located in Falls Church, Virginia. Accordingly, the Company no longer has any continuing involvement with 3141 Fairview Park Drive and recorded the partial sale under the full accrual method of accounting. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further information. (b) 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. See Note 4 “ Investment in Unconsolidated Real Estate Ventures, ” for further information. 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. (c) See footnote (a) to the “Real estate investments, at cost” table above for further information regarding this segment. (d) Investment in real estate ventures does not include the $1.1 million negative investment balance in one real estate venture as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture during the three-month period ended March 31, 2016. See Note 4, " Investment in Unconsolidated Real Estate Ventures ," for further information. The decrease to the Company’s investment balance primarily relates to distributions from the G&I VII Austin Office LLC real estate venture. Net operating income (“NOI”) is defined as total revenue less property operating expenses, real estate taxes and third party management expenses. Segment NOI includes revenue, real estate taxes and property operating expenses directly related to operation and management of the properties owned and managed within the respective geographical region. Segment NOI excludes property level depreciation and amortization, revenue and expenses directly associated with third party real estate management and development services, expenses associated with corporate administrative support services, and inter-company eliminations. NOI also does not reflect general and administrative expenses, interest expenses, real estate impairment losses, depreciation and amortization costs, capital expenditures and capitalized leasing costs. Trends in development and construction activities that could materially impact the Company’s results from operations are also not reflected in NOI. 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 also believes that NOI provides useful information to investors regarding its financial condition and results of operations because it reflects only those income and expenses recorded at the property level, as well as the impact on operations from trends in occupancy rates, rental rates, operating costs and acquisition and development activity on an unlevered basis. The Company believes that net income, as defined by GAAP, is an appropriate earnings measure. The following is a reconciliation of consolidated NOI to consolidated net income (loss), as defined by GAAP: Years Ended December 31, 2016 2015 2014 Consolidated net operating income $ 316,015 $ 364,544 $ 361,017 Less: Interest expense (84,708 ) (110,717 ) (124,329 ) Interest expense - amortization of deferred financing costs (2,696 ) (4,557 ) (5,148 ) Interest expense - financing obligation (679 ) (1,237 ) (1,144 ) Depreciation and amortization (189,676 ) (219,029 ) (208,569 ) General and administrative expenses (26,596 ) (29,406 ) (26,779 ) Equity in loss of real estate ventures (11,503 ) (811 ) (790 ) Provision for impairment (40,517 ) (82,208 ) (1,765 ) Plus: Interest income 1,236 1,224 3,974 Tax credit transaction income - 19,955 11,853 Recognized hedge activity - - (828 ) Net gain from remeasurement of investments in real estate ventures - 758 458 Net gain on sales of interests in real estate 116,983 20,496 4,901 Net gain on sale of undepreciated real estate 9,232 3,019 1,184 Net gain (loss) on real estate venture transactions 20,000 7,229 (417 ) Loss on early extinguishment of debt (66,590 ) - (7,594 ) Income (loss) from continuing operations 40,501 (30,740 ) 6,024 Income from discontinued operations - - 918 Net income (loss) $ 40,501 $ (30,740 ) $ 6,942

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2016
Leases Operating [Abstract]
OPERATING LEASES	19. OPERATING LEASES The Company leases properties to tenants under operating leases with various expiration dates extending to 2082. Minimum future rentals on non-cancelable leases at December 31, 2016 are as follows (in thousands): Year Minimum Rent 2017 $ 374,726 2018 370,439 2019 341,956 2020 311,075 2021 271,870 Thereafter 1,292,599 Total minimum future rentals presented above do not include amounts to be received as tenant reimbursements for operating costs.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	20. COMMITMENTS AND CONTINGENCIES Legal Proceedings The Company is involved from time to time in litigation on various matters, including disputes with tenants 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, the Company has funded required leasing and capital reserve accounts for the benefit of the mortgage lenders with letters-of-credit. There is an associated $10.0 million letter of credit for a mortgage lender at each of December 31, 2016 and December 31, 2015. 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 under the terms of all non-cancellable ground leases under which the Company is the lessee are expensed on a straight-line basis regardless of when payments are due. The Company’s ground leases have remaining lease terms ranging from 4 to 72 years. Minimum future rental payments on non-cancelable leases at December 31, 2016 are as follows (in thousands): Year Minimum Rent 2017 $ 1,339 2018 1,339 2019 1,339 2020 1,339 2021 1,339 Thereafter 66,231 Total $ 72,926 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. 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 recorded at a 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 December 31, 2016, the liability had accreted to $1.7 million. As there were no significant changes to the inputs, the liability remains within Level 3 for fair value reporting. Debt Guarantees As of December 31, 2016, the Company’s unconsolidated real estate ventures had aggregate indebtedness to third parties of $997.5 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 December 31, 2016, the loans for which there is recourse to the Company consists of the following: (i) a $3.2 million payment guarantee on the $56.0 million construction loan for TB-BDN Plymouth Apartments; (ii) a several cost overrun guaranty on the $88.9 million construction loan for the development project being undertaken by 1919 Market Street LP; and (iii) a $0.4 million payment guarantee on a loan provided to PJP VII. See Note 4, " Investment in Unconsolidated Real Estate Ventures “Subsequent Events,” Other Commitments or Contingencies 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. The Company is currently under agreement to sell 9.5 acres (of the 34.6 acres) to two 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 $10.3 million. Total estimated costs related to the improvements are included in the sale price of each land parcel. Recognition of the profit earned upon sale of the land parcels is deferred until the improvements are completed. See Note 21, “Subsequent Events,” On December 3, 2015, the Company entered into an agreement as development manager to construct Subaru of America’s (“Subaru”) corporate headquarters in Camden, New Jersey. The agreement provides the Company with the ability to earn additional profit if total project costs are less than the not-to-exceed (“NTE”) amount. The NTE amount, currently at $78.1 million, may be adjusted by change orders agreed upon by both Subaru and the Company. If construction costs are in excess of the NTE amount, the Company is obligated to pay such cost overruns. The terms of the guarantee do not provide a limitation on the costs the Company may be responsible for. As of December 31, 2016, the Company does not expect to incur costs in excess of the NTE amount. Also on December 3, 2015, the Company entered into an agreement to construct an 83,000 square foot build-to-suit service center As part of the Company’s September 2004 acquisition of a portfolio of properties from The Rubenstein Company (which the Company refers to as the “TRC acquisition”), the Company acquired its interest in Two Logan Square, a 708,844 square foot office building in Philadelphia, primarily through its ownership of a second and third mortgage secured by this property. This property is consolidated, as the borrower is a variable interest entity and the Company, through its ownership of the second and third mortgages, is the primary beneficiary. The Company currently does not expect to take title to Two Logan Square until, at the earliest, January 2020. If the Company takes fee title to Two Logan Square upon a foreclosure of its mortgage, the Company has agreed to pay an unaffiliated third party that holds a residual interest in the fee owner of this property an amount equal to $2.9 million. On the TRC acquisition date, the Company recorded a liability of $0.7 million and this amount will accrete up to $2.9 million through January 2020. As of December 31, 2016, the Company had a balance of $2.2 million for this liability in its consolidated balance sheet. As part of the Company’s 2006 merger with Prentiss Properties Trust (“Prentiss”), the 2004 TRC acquisition and several of our other transactions, the Company agreed not to sell certain of the properties it acquired in transactions that would trigger taxable income to the former owners. In the case of the TRC acquisition, the Company agreed not to sell acquired properties in non-exempt transactions for periods up to 15 years from the date of the TRC acquisition as follows at December 31, 2016: One Logan Square, Two Logan Square and Radnor Corporate Center (January, 2020). In the Prentiss acquisition, the Company assumed the obligation of Prentiss not to sell Concord Airport Plaza before March, 2018. See Note 21, “ Subsequent Events like-kind exchange under Section 1031. As part of the Company’s acquisition of properties from time to time in tax-deferred transactions, the Company has agreed to provide certain of the prior owners of the acquired properties with the right to guarantee the Company’s indebtedness. If the Company were to seek to repay the indebtedness guaranteed by the prior owner before the expiration of the applicable agreement, the Company would be required to provide the prior owner an opportunity to guaranty qualifying replacement debt. These debt maintenance agreements may limit the Company’s ability to refinance indebtedness on terms favorable to the Company. As part of our 2013 acquisition of substantially all of the equity interests in the partnerships that own One and Two Commerce Square, the Company agreed, for the benefit of affiliates of the holder of the 1% residual ownership interest in these properties, to maintain qualifying mortgage debt through October 20, 2021, in the amounts of not less than $125.0 million on One Commerce Square and $100.0 million on Two Commerce Square. Similarly, the Company has agreements in place with other contributors of assets that obligate it to maintain debt available for them to guaranty. 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	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	21. SUBSEQUENT EVENTS Concord Airport Plaza Sale On February 2, 2017, the Company completed the disposition of two office properties located at 1200 and 1220 Concord Avenue, in Concord, California, containing 350,256 net rentable square feet, for a gross sales price of $33.1 million. As the properties were impaired to fair value during the fourth quarter of 2016, there is an estimated gain of $0.5 million on sale. The sale is designated as a like-kind exchange under Section 1031 of the Internal Revenue Code (“IRC”) and, as such, the proceeds, totaling $32.0 million after closing costs and prorations, were delivered to a Qualified Intermediary, as defined under the IRC. The Parc at Plymouth Meeting Venture Sale On January 31, 2017, the Company sold its 50% interest in TB-BDN Plymouth Apartments, L.P., a 50/50 real estate venture with Toll Brothers, at a gross sales value of $100.5 million. The venture developed and operates a 398-unit multi-family complex in Plymouth Meeting, Pennsylvania encumbered by a $54.0 million construction loan. The construction loan was repaid commensurate with the sale of the Company’s 50% interest. As a result, the Company is no longer subject to a $3.2 million payment guarantee on the construction loan. The cash proceeds, after the payment of the Company’s share of the debt and closing costs, was $27.2 million. As the carrying amount of the Company’s investment at the time of sale is $23.3 million, the estimated gain is $14.6 million. Garza Land Sale On January 30, 2017, the Company disposed of 1.7 acres of land located in Austin, Texas, known as the Garza Ranch, for a sales price of $3.5 million. The land did not meet the criteria to be classified as a sale as of December 31, 2016. The Company has a continuing involvement through a completion guaranty, which requires the Company as developer to complete certain infrastructure improvements on behalf of the buyers of the land parcels. The cash received at settlement was recorded as “deferred income, gains and rent” on the Company’s balance sheet and the Company will recognize the sale once the infrastructure improvements are complete. At-the-Market Offering On January 10, 2017, the Company entered into a continuous offering program, under which it may sell up to an aggregate of 16,000,000 common shares until January 10, 2020 in at the market offerings. This program is a replacement of a prior continuous offering program that expired on November 3, 2016. The Company did not sell any shares under the prior program during 2016 and has not sold any shares under the new program through the date of this report.

Summary of Quarterly Results

Summary of Quarterly Results	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
SUMMARY OF QUARTERLY RESULTS (UNAUDITED)	22. SUMMARY OF QUARTERLY RESULTS (UNAUDITED) The following is a summary of quarterly financial information as of and for the years ended December 31, 2016 and 2015 (in thousands, except per share data): Brandywine Realty Trust 1st 2nd 3rd 4th Quarter Quarter Quarter Quarter 2016 Total revenue $ 136,502 $ 127,181 $ 129,694 $ 132,086 Net income (loss) 46,310 (1,323 ) 7,884 (12,370 ) Net income (loss) allocated to Common Shares 44,091 (3,105 ) 6,022 (14,058 ) Basic earnings (loss) per Common Share $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) Diluted earnings (loss) per Common Share $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) 2015 Total revenue $ 150,406 $ 145,648 $ 152,585 $ 153,992 Net income (loss) 8,594 3,058 20,308 (62,700 ) Net income (loss) allocated to Common Shares 6,710 1,255 18,346 (63,941 ) Basic earnings (loss) per Common Share $ 0.04 $ 0.01 $ 0.10 $ (0.37 ) Diluted earnings (loss) per Common Share $ 0.04 $ 0.01 $ 0.10 $ (0.37 ) The summation of quarterly earnings per share amounts do not necessarily equal the full year amounts due to rounding. Brandywine Operating Partnership, L.P. 1st 2nd 3rd 4th Quarter Quarter Quarter Quarter 2016 Total revenue $ 136,502 $ 127,181 $ 129,694 $ 132,086 Net income (loss) 46,310 (1,323 ) 7,884 (12,370 ) Net income (loss) attributable to Common Partnership Unitholders 44,478 (3,131 ) 6,074 (14,176 ) Basic earnings (loss) per Common Partnership Unit $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) Diluted earnings (loss) per Common Partnership Unit $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) 2015 Total revenue $ 150,406 $ 145,648 $ 152,585 $ 153,992 Net income (loss) 8,594 3,058 20,308 (62,700 ) Net income (loss) attributable to Common Partnership Unitholders 6,768 1,262 18,506 (64,502 ) Basic earnings (loss) per Common Partnership Unit $ 0.04 $ 0.04 $ 0.10 $ (0.36 ) Diluted earnings (loss) per Common Partnership Unit $ 0.04 $ 0.04 $ 0.10 $ (0.36 ) The summation of quarterly earnings per share amounts do not necessarily equal the full year amounts due to rounding.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2016
Valuation And Qualifying Accounts [Abstract]
Schedule of Valuation and Qualifying Accounts Disclosure	Brandywine Realty Trust and Brandywine Operating Partnership, L.P. Schedule II Valuation and Qualifying Accounts (in thousands) Description Balance at Beginning of Year Additions Deductions (1) Balance at End of Year Allowance for doubtful accounts: Year-ended December 31, 2016 $ 16,178 $ 2,207 $ 2,269 $ 16,116 Year-ended December 31, 2015 $ 15,347 $ 2,640 $ 1,809 $ 16,178 Year-ended December 31, 2014 $ 16,248 $ 790 $ 1,691 $ 15,347 (1) Deductions represent amounts that the Company had fully reserved for in prior years and for which the pursuit of collection of such amounts was ceased during the year.

Schedule III - Real Estate and

Schedule III - Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2016
Real Estate And Accumulated Depreciation Disclosure [Abstract]
Real Estate and Accumulated Depreciation Disclosure	BRANDYWINE REALTY TRUST AND BRANDYWINE OPERATING PARTNERSHIP, L.P. Schedule III Real Estate and Accumulated Depreciation — December 31, 2016 (in thousands) Initial Cost Gross Amount Which Carried December 31, 2016 (c) Property Name City State Encumbrances (a) Land Building & Improvements Net Improvements (Retirements) Since Acquisition Land Building & Improvements Total (b) Accumulated Depreciation at December 31, 2016 (c) Year of Construction Year Acquired Depreciable Life PENNSYLVANIA SUBURBS 400 Berwyn Park Berwyn PA - 2,657 4,462 13,383 2,657 17,845 20,502 7,132 1999 1999 40 300 Berwyn Park Berwyn PA - 2,206 13,422 4,014 2,206 17,436 19,642 9,213 1989 1997 40 1050 Westlakes Drive Berwyn PA - 2,611 10,445 6,130 2,611 16,575 19,186 9,450 1984 1999 40 1200 Swedesford Road Berwyn PA - 2,595 11,809 2,996 2,595 14,805 17,400 8,043 1994 2001 40 200 Berwyn Park Berwyn PA - 1,533 9,460 1,864 1,533 11,324 12,857 5,947 1987 1997 40 1180 Swedesford Road Berwyn PA - 2,086 8,342 3,110 2,086 11,452 13,538 4,429 1987 2001 40 100 Berwyn Park Berwyn PA - 1,180 7,290 1,483 1,180 8,773 9,953 4,508 1986 1997 40 1160 Swedesford Road Berwyn PA - 1,781 7,124 6,108 2,045 12,968 15,013 4,437 1986 2001 40 1100 Cassett Road Berwyn PA - 1,695 6,779 1,271 1,695 8,050 9,745 3,133 1997 2001 40 Six Tower Bridge (181 Washington Street) Conshohocken PA - 6,927 14,722 1,504 6,237 16,916 23,153 1,838 1999 2013 40 426 Lancaster Avenue Devon PA - 1,689 6,756 376 1,689 7,132 8,821 3,812 1990 1998 40 52 Swedesford Square East Whiteland Twp. PA - 4,241 16,579 3,852 4,241 20,431 24,672 8,834 1988 1998 40 640 Freedom Business Center King Of Prussia PA - 4,222 16,891 5,060 4,222 21,951 26,173 10,997 1991 1998 40 630 Allendale Road King of Prussia PA - 2,836 4,028 12,614 2,894 16,584 19,478 6,597 2000 2000 40 620 Freedom Business Center King Of Prussia PA - 2,770 11,014 2,115 2,770 13,129 15,899 7,064 1986 1998 40 1000 First Avenue King Of Prussia PA - 2,772 10,936 2,495 2,772 13,431 16,203 6,427 1980 1998 40 1060 First Avenue King Of Prussia PA - 2,712 10,953 4,261 2,712 15,214 17,926 6,705 1987 1998 40 630 Freedom Business Center King Of Prussia PA - 2,773 11,144 3,786 2,773 14,930 17,703 7,019 1989 1998 40 1020 First Avenue King Of Prussia PA - 2,168 8,576 7,627 2,168 16,203 18,371 8,469 1984 1998 40 1040 First Avenue King Of Prussia PA - 2,860 11,282 5,037 2,860 16,319 19,179 6,699 1985 1998 40 610 Freedom Business Center King Of Prussia PA - 2,017 8,070 2,878 2,017 10,948 12,965 5,174 1985 1998 40 650 Park Avenue King Of Prussia PA - 1,916 4,378 1,561 1,916 5,939 7,855 3,295 1968 1998 40 600 Park Avenue King Of Prussia PA - 1,012 4,048 385 1,012 4,433 5,445 2,286 1964 1998 40 14 Campus Boulevard Newtown Square PA - 2,244 4,217 1,533 2,244 5,750 7,994 4,008 1998 1998 40 17 Campus Boulevard Newtown Square PA - 1,108 5,155 (924) 1,108 4,231 5,339 1,595 2001 1997 40 11 Campus Boulevard Newtown Square PA - 1,112 4,067 998 1,112 5,065 6,177 2,286 1998 1999 40 15 Campus Boulevard Newtown Square PA - 1,164 3,896 285 1,164 4,181 5,345 1,485 2002 2000 40 18 Campus Boulevard Newtown Square PA - 787 3,312 856 787 4,168 4,955 1,844 1990 1996 40 401 Plymouth Road Plymouth Meeting PA - 6,199 16,131 16,815 6,199 32,946 39,145 12,591 2001 2000 40 Metroplex (4000 Chemical Road) Plymouth Meeting PA - 4,373 24,546 1,300 4,373 25,846 30,219 6,243 2007 2001 40 610 West Germantown Pike Plymouth Meeting PA - 3,651 14,514 3,337 3,651 17,851 21,502 6,986 1987 2002 40 600 West Germantown Pike Plymouth Meeting PA - 3,652 15,288 2,295 3,652 17,583 21,235 6,436 1986 2002 40 630 West Germantown Pike Plymouth Meeting PA - 3,558 14,743 1,630 3,558 16,373 19,931 6,002 1988 2002 40 620 West Germantown Pike Plymouth Meeting PA - 3,572 14,435 1,119 3,572 15,554 19,126 5,778 1990 2002 40 660 West Germantown Pike Plymouth Meeting PA - 3,694 5,487 19,487 5,405 23,263 28,668 3,359 1987 2012 30 351 Plymouth Road Plymouth Meeting PA - 1,043 555 - 1,043 555 1,598 163 N/A 2000 40 150 Radnor Chester Road Radnor PA - 11,925 36,986 11,990 11,897 49,004 60,901 20,032 1983 2004 29 One Radnor Corporate Center Radnor PA - 7,323 28,613 23,052 7,323 51,665 58,988 23,923 1998 2004 29 201 King of Prussia Road Radnor PA - 8,956 29,811 4,587 8,949 34,405 43,354 17,840 2001 2004 25 555 Lancaster Avenue Radnor PA - 8,014 16,508 17,847 8,609 33,760 42,369 15,559 1973 2004 24 Four Radnor Corporate Center Radnor PA - 5,406 21,390 13,271 5,705 34,362 40,067 12,531 1995 2004 30 Five Radnor Corporate Center Radnor PA - 6,506 25,525 5,540 6,578 30,993 37,571 10,392 1998 2004 38 Three Radnor Corporate Center Radnor PA - 4,773 17,961 2,615 4,791 20,558 25,349 9,654 1998 2004 29 Two Radnor Corporate Center Radnor PA - 3,937 15,484 4,075 3,942 19,554 23,496 8,510 1998 2004 29 130 Radnor Chester Road Radnor PA - 2,573 8,338 3,483 2,567 11,827 14,394 5,433 1983 2004 25 170 Radnor Chester Road Radnor PA - 2,514 8,147 2,864 2,509 11,016 13,525 3,992 1983 2004 25 200 Radnor Chester Road Radnor PA - 3,366 - 3,583 3,366 3,583 6,949 373 2014 2005 40 101 West Elm Street W. Conshohocken PA - 6,251 25,209 3,170 6,251 28,379 34,630 8,912 1999 2005 40 1 West Elm Street W. Conshohocken PA - 3,557 14,249 3,125 3,557 17,374 20,931 4,687 1999 2005 40 PHILADELPHIA CBD Cira Centre (2929 Arch Street) Philadelphia PA - - 208,570 (9,473) 12,586 186,511 199,097 63,153 2005 N/A 40 Three Logan Square (1717 Arch Street) Philadelphia PA - - 98,188 68,691 25,195 141,684 166,879 33,059 1990 2010 40 Two Commerce Square (2001 Market Street) Philadelphia PA 112,000 15,323 120,200 21,518 15,323 141,718 157,041 12,190 1992 2013 40 One Logan Square (130 North 18th Street) Philadelphia PA - 14,496 107,736 27,447 14,473 135,206 149,679 46,840 1998 2004 34 Two Logan Square (100 North 18th Street) Philadelphia PA 86,012 16,066 100,255 17,631 16,066 117,886 133,952 37,378 1988 2004 36 One Commerce Square (2005 Market Street) Philadelphia PA 127,026 15,161 105,021 21,419 15,160 126,441 141,601 11,190 1987 2013 40 Cira Centre South Garage (d) Philadelphia PA - - 76,008 7,588 - 83,596 83,596 12,504 2010 N/A 40 1900 Market Street Philadelphia PA - 7,768 17,263 27,176 7,768 44,439 52,207 4,389 1981 2012 30 3020 Market Street Philadelphia PA - - 21,417 7,651 - 29,068 29,068 6,105 1959 2011 26 The Lift at Juniper Street (101 - 103 Juniper Street) Philadelphia PA - - 14,401 324 478 14,247 14,725 2,915 2010 2006 40 Philadelphia Marine Center Philadelphia PA - 532 2,196 4,317 628 6,417 7,045 2,965 Various 1998 40 618-634 Market Street (e) Philadelphia PA - 13,365 5,791 460 13,365 6,251 19,616 2,056 1966 2015 5 FMC Tower at Cira Centre South Philadelphia PA - - 166,474 - - 166,474 166,474 3,325 2016 N/A 40 METROPOLITAN WASHINGTON, D.C. 11720 Beltsville Drive (f), (g) Beltsville MD - 3,831 16,661 (8,065) 1,472 10,955 12,427 6,066 1987 2006 46 11700 Beltsville Drive (f), (g) Beltsville MD - 2,808 12,081 (10,823) 257 3,809 4,066 2,999 1981 2006 46 11710 Beltsville Drive (f), (g) Beltsville MD - 2,278 11,100 (9,060) 408 3,910 4,318 2,615 1987 2006 46 11740 Beltsville Drive (f), (g) Beltsville MD - 198 870 (159) 155 754 909 255 1987 2006 46 6600 Rockledge Drive Bethesda MD - - 37,421 10,700 - 48,121 48,121 11,894 1981 2006 50 2340 Dulles Corner Boulevard Herndon VA - 16,345 65,379 5,188 16,129 70,783 86,912 21,568 1987 2006 40 2291 Wood Oak Drive Herndon VA - 8,243 52,413 12,543 8,782 64,417 73,199 17,417 1999 2006 55 2251 Corporate Park Drive Herndon VA - 11,472 45,893 3,411 11,472 49,304 60,776 12,696 2000 2006 40 2355 Dulles Corner Boulevard Herndon VA - 10,365 43,876 4,510 10,365 48,386 58,751 15,120 1988 2006 40 2411 Dulles Corner Park Herndon VA - 7,279 46,340 18,759 7,417 64,961 72,378 13,783 1990 2006 50 13880 Dulles Corner Lane Herndon VA - 7,236 39,213 4,458 7,373 43,534 50,907 10,044 1997 2006 55 2121 Cooperative Way Herndon VA - 5,598 38,639 2,793 5,795 41,235 47,030 9,814 2000 2006 54 2201 Cooperative Way Herndon VA - 4,809 34,093 6,051 4,809 40,144 44,953 9,918 1990 2006 54 13825 Sunrise Valley Drive Herndon VA - 3,794 19,365 2,485 3,866 21,778 25,644 6,283 1989 2006 46 1676 International Drive Mclean VA - 18,437 97,538 3,307 18,785 100,497 119,282 21,039 1999 2006 55 8260 Greensboro Drive Mclean VA - 7,952 33,964 2,873 8,102 36,687 44,789 9,000 1980 2006 52 2273 Research Boulevard Rockville MD - 5,167 31,110 4,153 5,237 35,193 40,430 8,885 1999 2006 45 2275 Research Boulevard Rockville MD - 5,059 29,668 8,227 5,154 37,800 42,954 10,439 1990 2006 45 2277 Research Boulevard Rockville MD - 4,649 26,952 18,863 4,733 45,731 50,464 10,051 1986 2006 45 1900 Gallows Road Vienna VA - 7,797 47,817 12,386 7,944 60,056 68,000 15,234 1989 2006 52 8521 Leesburg Pike Vienna VA - 4,316 30,885 6,201 4,397 37,005 41,402 8,321 1984 2006 51 AUSTIN, TX 11501 Burnet Road - Building 1 Austin TX - 3,755 22,702 144 3,755 22,846 26,601 1,071 1991 2015 35 11501 Burnet Road - Building 2 Austin TX - 2,732 16,305 1,518 2,732 17,823 20,555 936 1991 2015 35 11501 Burnet Road - Building 3 Austin TX - 3,688 22,348 142 3,688 22,490 26,178 1,055 1991 2015 35 11501 Burnet Road - Building 4 Austin TX - 2,614 15,740 100 2,614 15,840 18,454 743 1991 2015 35 11501 Burnet Road - Building 5 Austin TX - 3,689 22,354 142 3,689 22,496 26,185 1,055 1991 2015 35 11501 Burnet Road - Building 8 Austin TX - 1,400 7,422 47 1,400 7,469 8,869 357 1991 2015 35 11501 Burnet Road - Parking Garage Austin TX - - 19,826 126 - 19,952 19,952 1,248 1991 2015 35 OTHER 200 Lake Drive East (h) Cherry Hill NJ - 2,069 8,275 (844) 1,440 8,060 9,500 3,995 1989 2001 40 220 Lake Drive East (h) Cherry Hill NJ - 2,144 8,798 (713) 1,492 8,737 10,229 4,093 1988 2001 40 210 Lake Drive East (h) Cherry Hill NJ - 1,645 6,579 564 1,145 7,643 8,788 3,618 1986 2001 40 1200 Concord Avenue (f), (i) Concord CA - 6,395 24,664 (5,168) 4,748 21,143 25,891 10,481 1984 2006 34 1220 Concord Avenue (f), (i) Concord CA - 6,476 24,966 (5,463) 4,719 21,260 25,979 10,500 1984 2006 34 20 East Clementon Road Gibbsboro NJ - 769 3,055 500 719 3,605 4,324 1,815 1986 1997 40 10 Foster Avenue Gibbsboro NJ - 244 971 69 244 1,040 1,284 544 1983 1997 40 7 Foster Avenue Gibbsboro NJ - 231 921 75 231 996 1,227 520 1983 1997 40 2 Foster Avenue Gibbsboro NJ - 185 730 58 185 788 973 382 1974 1997 40 4 Foster Avenue Gibbsboro NJ - 183 726 30 183 756 939 376 1974 1997 40 1 Foster Avenue Gibbsboro NJ - 93 364 30 93 394 487 212 1972 1997 40 5 U.S. Avenue Gibbsboro NJ - 21 81 2 21 83 104 43 1987 1997 40 5 Foster Avenue Gibbsboro NJ - 9 32 26 9 58 67 32 1968 1997 40 Two Eves Drive Marlton NJ - 818 3,461 269 818 3,730 4,548 1,897 1987 1997 40 Five Eves Drive Marlton NJ - 703 2,819 1,456 703 4,275 4,978 1,996 1986 1997 40 Four B Eves Drive Marlton NJ - 588 2,369 185 588 2,554 3,142 1,377 1987 1997 40 Four A Eves Drive Marlton NJ - 539 2,168 608 539 2,776 3,315 1,305 1987 1997 40 7000 Midlantic Drive Mt. Laurel NJ - 2,560 2,790 - 2,560 2,790 5,350 51 2016 2003 40 Main Street - Plaza 1000 Voorhees NJ - 2,732 10,942 95 2,732 11,037 13,769 11,012 1988 1997 40 Main Street - Piazza Voorhees NJ - 696 2,802 3,442 696 6,244 6,940 2,375 1990 1997 40 Main Street - Promenade Voorhees NJ - 532 2,052 525 532 2,577 3,109 1,379 1988 1997 40 920 North King Street Wilmington DE - 6,141 21,140 3,599 6,141 24,739 30,880 9,090 1989 2004 30 300 Delaware Avenue Wilmington DE - 6,369 13,739 3,032 6,369 16,771 23,140 8,202 1989 2004 23 Total: $ 325,038 $ 450,881 $ 2,669,016 $ 539,989 $ 481,282 $ 3,178,604 $ 3,659,886 $ 885,392 (a) Excludes the effect of any net interest premium/(discount) and deferred financing costs. (b) Reconciliation of Real Estate: The following table reconciles the real estate investments from January 1, 2014 to December 31, 2016 (in thousands): 2016 2015 2014 Balance at beginning of year $ 4,487,588 $ 4,631,128 $ 4,669,289 Additions: Acquisitions - 182,381 - Capital expenditures and assets placed into service 213,996 165,941 132,149 Less: Dispositions/impairments/placed into redevelopment (962,676 ) (442,327 ) (126,471 ) Retirements (79,022 ) (49,535 ) (43,839 ) Balance at end of year $ 3,659,886 $ 4,487,588 $ 4,631,128 Less: Assets held for sale (73,591 ) (794,588 ) (27,436 ) Per consolidated balance sheet $ 3,586,295 $ 3,693,000 $ 4,603,692 The aggregate cost for federal income tax purposes is $3.0 billion as of December 31, 2016. (c) Reconciliation of Accumulated Depreciation: The following table reconciles the accumulated depreciation on real estate investments from January 1, 2014 to December 31, 2016 (in thousands): 2016 2015 2014 Balance at beginning of year $ 1,080,616 $ 1,078,996 $ 983,808 Additions: Depreciation expense 131,859 159,080 160,641 Less: Dispositions/impairments/placed into redevelopment (250,110 ) (109,243 ) (22,459 ) Retirements (76,973 ) (48,217 ) (42,994 ) Balance at end of year $ 885,392 $ 1,080,616 $ 1,078,996 Less: Assets held for sale (32,916 ) (213,581 ) (11,167 ) Per consolidated balance sheet $ 852,476 $ 867,035 $ 1,067,829 (d) On January 14 2016, the Company f unded $44.4 million, consisting of $35.5 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness (e) At acquisition it was determined that the useful life of the parking structure is five years, which reflects the expected demolition date. (f) Properties were held for sale at December 31, 2016. (g) In connection with the held for sale determination the Company recorded an impairment charge of $3.0 million as of December 31, 2016, reducing the aggregate carrying value of these properties from $13.3 million to the sales price less estimated closing costs of $10.3 million in connection with the anticipated dispositions. The impairment was allocated between land and building. For further information, see Note 3, “ Real Estate Investments (h) The Company evaluated the recoverability of the carrying value of these properties, and determined that due to the shortening of the expected hold periods of ownership, it was necessary to reduce the carrying value to estimated fair value. Accordingly, the Company recorded an impairment charge of $7.3 million as of December 31, 2016, reducing the aggregate carrying value of these properties from $25.8 million to their estimated fair value of $18.5 million. For further information see Note 3, “ Real Estate Investments (i) In connection with the held for sale determination, the Company recorded an impairment charge of $11.5 million as of December 31, 2016, reducing the aggregate carrying value of these properties from $43.5 million to the sales price, less estimated closing costs, of $32.0 million in connection with the anticipated dispositions. The impairment was allocated between land and building. For further information, see Note 3, “ Real Estate Investments

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The Company consolidates variable interest entities (“VIEs”) in which it is considered to be the primary beneficiary. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or that the holders of the equity investment at risk do not have a controlling financial interest. The primary beneficiary is defined by the entity having both of the following characteristics: (i) the power to direct those matters that most significantly impacted the activities of the VIE and (ii) the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to the VIE. For entities that the Company has the obligations to fund losses, its maximum exposure to loss is not limited to the carrying amount of its investments. As of December 31, 2016, the Company’s unconsolidated real estate ventures had aggregate indebtedness to third parties of $997.5 million. These loans are generally mortgage or construction loans, most of which are non-recourse to the Company. As of December 31, 2016, the loans for which there is recourse to the Company consists of the following: (i) a $52.5 million payment guaranty on the term loan for evo at Cira; (ii) a $3.2 million payment guarantee on the $56.0 million construction loan for TB-BDN Plymouth Apartments; (iii) a joint and several cost overrun guaranty on the $88.9 million construction loan for the development project being undertaken by 1919 Market Street LP; and (iv) a $0.4 million payment guarantee on a loan provided to PJP VII. On January 31, 2017, the Company sold its 50% interest in TB-BDN Plymouth Apartments, L.P. and the Company’s $3.2 million guarantee was cancelled. See Note 21, “Subsequent Events,” When an entity is not deemed to be a VIE, the Company consolidates entities for which it has significant decision making control over the entity’s operations. The Company’s judgement with respect to its level of influence or control of an entity involves consideration of various factors including the form of the Company’s ownership interest, its representation in the entity’s governance, the size of its investment (including loans), estimates of future cash flows, its ability to participate in policy making decisions and the rights of the other investors to participate in the decision making process and to replace the Company as manager and/or liquidate the venture, if applicable. The Company’s assessment of its influence or control over an entity affects the presentation of these investments in the Company’s consolidated financial statements. In addition to evaluating control rights, the Company consolidates entities in which the outside partner has no substantive kick-out rights to remove the Company as managing member. The Company continuously assesses its determination of the primary beneficiary for each entity and assesses reconsideration events that may cause a change in the original determinations. The portion of the consolidated entities that is not owned by the Company is presented as non-controlling interest as of and during the periods consolidated. All intercompany transactions have been eliminated in consolidation. As of December 31, 2016 and 2015, the Company included in its consolidated balance sheets consolidated VIEs having total assets of $417.1 million and $422.9 million, respectively, and total liabilities of $254.6 million and $258.2 million, respectively.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates. Management makes significant estimates regarding revenue, valuation of real estate and related intangible assets and liabilities, impairment of long-lived assets, land held for development, allowance for doubtful accounts and deferred costs.
Operating Properties	Operating Properties Operating properties are carried at historical cost less accumulated depreciation and impairment losses. The cost of operating properties reflects their purchase price or development cost. Acquisition costs related to business combinations are expensed as incurred, whereas the costs related to asset acquisitions are capitalized as incurred. Costs incurred for the renovation and betterment of an operating property are capitalized to the Company’s investment in that property. Ordinary repairs and maintenance are expensed as incurred.
Purchase Price Allocation	Purchase Price Allocation The Company allocates the purchase price of properties considered to be business combinations to net tangible and identified intangible assets acquired based on fair values. Above-market and below-market in-place lease values for acquired properties are recorded based on the present value (using an interest rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to the in-place leases and (ii) the Company’s estimate of the fair market lease rates for the corresponding in-place leases, measured over a period equal to the remaining non-cancelable term of the lease (including the below market fixed renewal period, if applicable). Capitalized above-market lease values are amortized as a reduction of rental income over the remaining non-cancelable terms of the respective leases. Capitalized below-market lease values are amortized as an increase to rental income over the remaining non-cancelable terms of the respective leases, including any below market fixed-rate renewal option periods that are considered probable. Other intangible assets also include in-place leases based on the Company’s evaluation of the specific characteristics of each tenant’s lease and the Company’s overall relationship with the respective tenant. The Company estimates the cost to execute leases with terms similar to the remaining lease terms of the in-place leases, including leasing commissions, legal and other related expenses. This intangible asset is amortized to expense over the remaining term of the respective leases and any fixed-rate bargain renewal periods. Company estimates of value are made using methods similar to those used by independent appraisers or by using independent appraisals. Factors considered by the Company in this analysis include an estimate of the carrying costs during the expected lease-up periods considering current market conditions and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rents at market rates during the expected lease-up periods, which primarily range from four to twelve months. The Company also considers information obtained about each property as a result of its pre-acquisition due diligence, marketing and leasing activities in estimating the fair value of the tangible and intangible assets acquired. The Company also uses the information obtained as a result of its pre-acquisition due diligence as part of its consideration of the accounting standard governing asset retirement obligations and when necessary, will record a conditional asset retirement obligation as part of its purchase price. The Company also evaluates tenant relationships on a tenant-specific basis. On certain of the Company’s acquisitions this intangible has been deemed immaterial, in which case no related intangible asset value is assigned. In the event that a tenant terminates its lease, the unamortized portion of each intangible, including in-place lease values and tenant relationship values, is charged to expense and market rate adjustments (above or below) are recorded to revenue. The Company records development acquisitions that do not meet the accounting criteria to be accounted for as business combinations at the purchase price paid. Costs directly associated with development acquisitions accounted for as asset acquisitions are capitalized as part of the cost of the acquisition.
Depreciation and Amortization	Depreciation and Amortization The costs of buildings and improvements are depreciated using the straight-line method based on the following useful lives: buildings and improvements (5 to 55 years) and tenant improvements (the shorter of (i) the life of the asset, 1 to 16 years, or (ii) the lease term).
Construction-in-Progress	Construction-in-Progress Project costs directly associated with the development and construction of a real estate project are capitalized as construction-in-progress. Construction-in-progress also includes costs related to ongoing tenant improvement projects. In addition, interest, real estate taxes and other expenses that are directly associated with the Company’s development activities are capitalized until the property is placed in service. Interest expense is capitalized using the Company’s average interest rate. Internal direct costs are capitalized to projects in which qualifying expenditures are being incurred. Internal direct construction costs totaling $6.7 million in 2016, $7.3 million in 2015, $5.2 million in 2014 and interest totaling $10.9 million in 2016, $10.2 million in 2015, and $4.8 million in 2014 were capitalized related to development of certain properties and land holdings. During the years ended December 31, 2016, 2015 and 2014, the Company’s internal direct construction costs are comprised entirely of capitalized salaries. The following table shows the amount of compensation costs (including bonuses and benefits) capitalized for the years presented (in thousands): December 31, 2016 2015 2014 Development $ 3,182 $ 2,641 $ 1,749 Redevelopment 144 221 184 Tenant Improvements 3,391 4,429 3,261 Total $ 6,717 $ 7,291 $ 5,194
Impairment or Disposal of Long-Lived Assets	Impairment or Disposal of Long-Lived Assets The Company reviews its long-lived assets for impairment following the end of each quarter using cash flow projections and estimated fair values for each of the properties included within its impairment analysis. The Company updates leasing and other assumptions regularly, paying particular attention to properties where there is an event or change in circumstances that indicates an impairment in value. Additionally, the Company considers strategic decisions regarding the future development plans for property under development and other market factors. For long-lived assets to be held and used, the Company analyzes recoverability based on the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the assets over, in most cases, a 10-year hold period. If there is significant possibility that the Company will dispose of assets earlier, it analyzes the recoverability using a probability weighted analysis of the undiscounted future cash flows expected to be generated from the operations and eventual disposition of each asset using various possible hold periods. If the recovery analysis indicates that the carrying value of the tested property is not recoverable, the property is written down to its fair value and an impairment loss is recognized. In such case, an impairment loss is recognized in the amount of the excess of the carrying amount of the asset over its fair value. If and when the Company’s plans change, it revises its recoverability analysis to use cash flows expected from operations and eventual disposition of each asset using hold periods that are consistent with its revised plans. Estimated cash flows used in such analysis are based on the Company’s plans for the property and its views of market economic conditions. The estimates consider factors such as current and future rental rates, occupancies for the tested property and comparable properties, estimated operating and capital expenditures and recent sales data for comparable properties; most of these factors are influenced by market data obtained from real estate leasing and brokerage firms and the Company’s direct experience with the properties and their markets. The Company generally considers assets to be “held for sale” when the transaction has been approved by its Board of Trustees, or by officers vested with authority to approve the transaction, and there are no known significant contingencies relating to the sale of the property within one year of the consideration date and the consummation of the transaction is otherwise considered probable. When a property is designated as held for sale, the Company stops depreciating the property and estimate the property’s fair value, net of selling costs. If the determination is made that the estimated fair value, net of selling costs, is less than the net carrying value of the property, an impairment loss is recognized, reducing the net carrying value of the property to estimated fair value less selling costs. For periods in which a property is classified as held for sale, the Company classifies the assets of the property as held for sale on the consolidated balance sheet for such periods. The relevant accounting guidance for impairments requires that qualifying assets and liabilities and the results of operations that have been sold, or otherwise qualify as “held for sale,” be presented as discontinued operations in all periods presented if the disposal represents a strategic shift that has, or will have, a major effect on the Company’s operations and financial results. The components of the property’s net income that is reflected as discontinued operations include the net gain (or loss) upon the disposition of the property held for sale, operating results, depreciation and interest expense (if the property is subject to a secured loan).
Impairment of Land Held for Development	Impairment of Land Held for Development When demand for build-to-suit office space declines and the ability to sell land held for development deteriorates, or other market factors indicate a possible impairment in the recoverability of land held for development, it is reviewed for impairment by comparing its fair value to its carrying value. If the estimated sales value is less than the carrying value, the carrying value is written down to its estimated fair value.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents are highly-liquid investments with original maturities of three months or less. The Company maintains cash equivalents in money market accounts with financial institutions in excess of insured limits, but believes this risk is mitigated by only investing in or through major financial institutions. The Company does not invest its available cash balances in money market funds, as such available cash balances are appropriately reflected as cash and cash equivalents on its consolidated balance sheet.
Restricted Cash	Restricted Cash Restricted cash consists of cash held as collateral to provide credit enhancement for the Company’s mortgage debt, cash for property taxes, capital expenditures and tenant improvements. Escrows also include cash held by qualified intermediaries for possible investments in like-kind exchanges in accordance with Section 1031 of the Internal Revenue Code in connection with sales of the Company’s properties. Restricted cash is included in the “Other assets” caption in the consolidated balance sheets.
Accounts Receivable And Accrued Rent Receivable	Accounts Receivable and Accrued Rent Receivable Generally, leases with tenants are accounted for as operating leases. Minimum annual rentals under tenant leases are recognized on a straight-line basis over the term of the related lease. The cumulative difference between lease revenue recognized under the straight-line method and contractual lease payment terms is recorded as “Accrued rent receivable, net” on the accompanying consolidated balance sheets. Included in current tenant receivables are tenant reimbursements which are comprised of amounts recoverable from tenants for common area maintenance expenses and certain other recoverable expenses that are recognized as revenue in the period in which the related expenses are incurred. As of December 31, 2016 and 2015, no tenant represented more than 10% of accounts receivable and accrued rent receivable. Tenant receivables and accrued rent receivables are carried net of the allowances for doubtful accounts of $2.4 million and $13.7 million in 2016, respectively, and $1.7 million and $14.5 million in 2015, respectively. The allowance is an estimate based on two calculations that are combined to determine the total amount reserved. First, the Company evaluates specific accounts where it has determined that a tenant may have an inability to meet its financial obligations. In these situations, the Company uses its judgment, based on the facts and circumstances, and records a specific reserve for that tenant against amounts due to reduce the receivable to the amount that the Company expects to collect. These reserves are reevaluated and adjusted as additional information becomes available. Second, a reserve is established for all tenants based on a range of percentages applied to receivable aging categories for tenant receivables. For accrued rent receivables, the Company considers the results of the evaluation of specific accounts and also considers other factors including assigning risk factors to different industries based on its tenants Standard Industrial Classification (SIC). Considering various factors including assigning a risk factor to different industries, these percentages are based on historical collection and write-off experience adjusted for current market conditions, which requires management’s judgments.
Investments in Unconsolidated Real Estate Ventures	Investments in Unconsolidated Real Estate Ventures Under the equity method, investments in unconsolidated Real Estate Ventures are recorded initially at cost, as Investments in unconsolidated Real Estate Ventures, and subsequently adjusted for equity in earnings, cash contributions, distributions and impairments. For Real Estate Ventures that are constructing assets to commence planned principal operations, the Company capitalizes interest expense using the Company’s weighted average interest rate of consolidated debt and its investment balance as a basis. Planned principal operations commence when a property is available to lease and at that point in time the Company ceases capitalizing interest to its investment basis. During the twelve months ended December 31, 2016, the Company capitalized interest expense of $1.9 million. In each of the twelve months ended December 31, 2015 and 2014, the Company capitalized interest expense of $2.0 million. On a periodic basis, management also assesses whether there are any indicators that the value of the Company’s investments in unconsolidated Real Estate Ventures may be other than temporarily impaired. An investment is impaired only if the value of the investment, as estimated by management, is less than the carrying value of the investment and the decline is other than temporary. To the extent that an impairment has occurred, the loss shall be measured as the excess of the carrying amount of the investment over the fair value of the investment, as estimated by management. The determination as to whether an impairment exists requires significant management judgment about the fair value of its ownership interest. Fair value is determined through various valuation techniques, including but not limited to, discounted cash flow models, quoted market values and third party appraisals. When the Company acquires an interest in or contributes assets to a real estate venture project, the difference between the Company’s cost basis in the investment and the value of the real estate venture or asset contributed is amortized over the life of the related assets, intangibles and liabilities and such adjustment is included in the Company’s share of equity in income of unconsolidated Real Estate Ventures. For purposes of cash flow presentation, distributions from unconsolidated Real Estate Ventures are presented as part of operating activities when they are considered as return on investments. Distributions in excess of the Company’s share in the cumulative unconsolidated Real Estate Ventures’ earnings are considered as return of investments and are presented as part of investing activities in accordance with the accounting standard for cash flow presentation.
Deferred Costs	Deferred Costs Costs incurred in connection with property leasing are capitalized as deferred leasing costs. Deferred leasing costs consist primarily of leasing commissions and internal leasing costs that are amortized using the straight-line method over the life of the respective lease which generally ranges from 1 to 16 years. Management re-evaluates the remaining useful lives of leasing costs as economic and market conditions change.
Notes Receivable	Notes Receivable The Company accounts for notes receivable on its balance sheet at amortized cost, net of allowance for loan losses. Interest income is recognized over the term of the notes receivable and is calculated based on the terms on the contractual terms of each note agreement. Notes receivable are placed on nonaccrual status when management determines, after considering economic and business conditions and collection efforts, that the loans are impaired or collection of interest is doubtful. Uncollectible interest previously accrued is recognized as bad debt expense. Interest income on nonaccrual loans is recognized only to the extent that cash payments are received. A note receivable was given to an unaffiliated third party during the third quarter of 2016 to facilitate its acquisition and development of an industrial facility located in Pennsauken, New Jersey. The loan matures three years after the payment commencement date, which is 90 days after substantial completion of the development, and bears interest at 6.3% during year one, 7.0% during year two and 8.0% during year three. The Company evaluated its investment in the note receivable under ASC 310, Receivables
Deferred Financing Costs	Deferred Financing Costs Costs incurred in connection with debt financing are capitalized as a direct deduction from the carrying value of the debt, except for costs capitalized related to the Company’s revolving credit facility, which are capitalized within “deferred costs, net” on the accompanying consolidated balance sheets. Deferred financing costs are charged to interest expense over the terms of the related debt agreements. Deferred financing costs consist primarily of loan fees which are amortized over the related loan term on a basis that approximates the effective interest method. Deferred financing costs are accelerated, when debt is extinguished, as part of “ Interest expense-amortization of deferred financing costs
Revenue Recognition	Revenue Recognition Rental revenue is recognized on the straight-line basis, which averages minimum rents over the terms of the leases from the later of the date of the commencement of the lease or the date of acquisition of the property subject to existing leases. The straight-line rent adjustment increased revenue by approximately $26.3 million in 2016, $21.6 million in 2015 and $13.7 million in 2014. Deferred rents on the balance sheet represent rental revenue received prior to their due dates and amounts paid by the tenant for certain improvements considered to be landlord assets that will remain as the Company’s property at the end of the tenant’s lease term. The amortization of the amounts paid by the tenant for such improvements is calculated on a straight-line basis over the term of the tenant’s lease and is a component of straight-line rental income and increased revenue by $2.1 million in 2016, $2.0 million in 2015 and $2.4 million in 2014. Lease incentives, which are included as reductions of rental revenue in the accompanying consolidated statements of operations, are recognized on a straight-line basis over the term of the lease. Lease incentives decreased revenue by $2.0 million in 2016, $1.8 million in 2015, and $1.5 million in 2014. In addition, the Company’s rental revenue is impacted by the Company’s determination of whether improvements to the properties, whether made by the Company or by the tenant, are landlord assets. The determination of whether an improvement is a landlord asset requires judgment. In making this judgment, the Company’s primary consideration is whether the improvement would be utilizable by another tenant upon move out of the improved space by the then-existing tenant. If the Company has funded an improvement that it determines not to be landlord assets, then it treats the cost of the improvement as a lease incentive. If the tenant has funded the improvement that the Company determines to be landlord assets, then the Company treats the costs of the improvement as deferred revenue and amortizes this cost into revenue over the lease term. For certain leases, the Company makes significant assumptions and judgments in determining the lease term, including assumptions when the lease provides the tenant with an early termination option. The lease term impacts the period over which the Company determines and records minimum rents and also impacts the period over which the Company amortizes lease-related costs. The Company’s leases also typically provide for tenant reimbursement of a portion of common area maintenance expenses and other operating expenses to the extent that a tenant’s pro rata share of expenses exceeds a base year level set in the lease or to the extent that the tenant has a lease on a triple net basis. Recoveries from tenants, consisting of amounts due from tenants for common area maintenance expenses, real estate taxes and other recoverable costs are recognized as revenue in the period during which the expenses are incurred. Tenant reimbursements are recognized and presented in accordance with accounting guidance which requires that these reimbursements be recorded on a gross basis because the Company is generally the primary obligor with respect to the goods and services the purchase of which gives rise to the reimbursement obligation; because the Company has discretion in selecting the vendors and suppliers; and because the Company bears the credit risk in the event they do not reimburse the Company. The Company also receives payments from third parties for reimbursement of a portion of the payroll and payroll-related costs for certain of the Company’s personnel allocated to perform services for these third parties and reflects these payments on a gross basis. The Company recognizes gains on sales of real estate at times and in amounts determined in accordance with the accounting guidance for sales of real estate. The guidance takes into account the terms of the transaction and any continuing involvement, including in the form of management, leasing of space or financial assistance associated with the properties. If the sales criteria for the full accrual method are not met, then the Company defers some or all of the gain recognition and accounts for the continued operations of the property by applying the finance, leasing, profit sharing, deposit, installment or cost recovery method, as appropriate, until the sales criteria are met. The Company derives parking revenues from leases, monthly parking and transient parking. The Company recognizes parking revenue as earned. The Company receives leasing commission income, property management fees and third party development fees. Leasing commission income is earned based on a percentage of gross rental income upon a tenant signing a lease with a third party lessor. Property management fees are recorded and earned based on a percentage of collected rents at the properties under management, and not on a straight-line basis, because such fees are contingent upon the collection of rents. The Company records development fees on a percentage of completion basis taking into account the risk associated with each project. The Company recognizes fees received for lease terminations as revenue and writes off against such revenue any deferred rents receivable. The resulting net amount is the net revenue from the early termination of the leases. When a tenant's lease for space in a property is terminated early but the tenant continues to lease such space under a new or modified lease in the property, the net revenue from the early termination of the lease is recognized evenly over the remaining life of the new or modified lease in place on that property, unless the Company cannot determine that collectability of the lease termination revenue is reasonably assured. No tenant represented greater than 10% of the Company’s rental revenue in 2016, 2015 or 2014.
Income Taxes	Income Taxes Parent Company The Parent Company has elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended (the “Code”). In order to continue to qualify as a REIT, the Parent Company is required to, among other things, distribute at least 90% of its annual REIT taxable income to its shareholders and meet certain tests regarding the nature of its income and assets. As a REIT, the Parent Company is not subject to federal and state income taxes with respect to the portion of its income that meets certain criteria and is distributed annually to its shareholders. Accordingly, a nominal provision for federal and state income taxes is included in the accompanying consolidated financial statements with respect to the operations of the Parent Company. The Parent Company intends to continue to operate in a manner that allows it to meet the requirements for taxation as a REIT. If the Parent Company fails to qualify as a REIT in any taxable year, it will be subject to federal and state income taxes and may not be able to qualify as a REIT for the four subsequent tax years. The Parent Company is subject to certain local income taxes. Provision for such taxes has been included in general and administrative expenses in the Parent Company’s Consolidated Statements of Operations and Comprehensive Income. The tax basis of the Parent Company’s assets was $3.0 billion and $3.9 billion for the years ended December 31, 2016 and 2015, respectively. The Parent Company is subject to a 4% federal excise tax if sufficient taxable income is not distributed within prescribed time limits. The excise tax equals 4% of the annual amount, if any, by which the sum of (a) 85% of the Parent Company’s ordinary income and (b) 95% of the Parent Company’s net capital gain exceeds cash distributions and certain taxes paid by the Parent Company. No excise tax was incurred in 2016, 2015 or 2014. The Parent Company has elected to treat several of its subsidiaries as taxable REIT subsidiaries (each a “TRS”). A TRS is subject to federal, state and local income tax. In general, a TRS may perform non-customary services for tenants, hold assets that the Parent Company, as a REIT, cannot hold directly and generally may engage in any real estate or non-real estate related business. The Company’s taxable REIT subsidiaries did not have significant tax provisions or deferred income tax items as of December 31, 2016 and 2015. The Protecting Americans from Tax Hikes Act (PATH Act) was enacted in December 2015, and included numerous law changes applicable to REITs. The provisions have various effective dates beginning as early as 2016. The changes have not materially impacted the Company’s operations, but the Company will continue to monitor as regulatory guidance is issued. Operating Partnership In general, the Operating Partnership is not subject to federal and state income taxes, and accordingly, no provision for income taxes has been made in the accompanying consolidated financial statements. The partners of the Operating Partnership are required to include their respective share of the Operating Partnership’s profits or losses in their respective tax returns. The Operating Partnership’s tax returns and the amount of allocable Partnership profits and losses are subject to examination by federal and state taxing authorities. If such examination results in changes to the Operating Partnership profits or losses, then the tax liability of the partners would be changed accordingly. The tax basis of the Operating Partnership’s assets was $3.0 billion and $3.9 billion for the years ended December 31, 2016 and 2015, respectively. The Operating Partnership may elect to treat one or more of its subsidiaries as REITs under Sections 856 through 860 of the Code. Each subsidiary REIT has met the requirements for treatment as a REIT under Sections 856 through 860 of the Code, and, accordingly, no provision has been made for federal and state income taxes in the accompanying consolidated financial statements. If any subsidiary REIT fails to qualify as a REIT in any taxable year, that subsidiary REIT will be subject to federal and state income taxes and may not be able to qualify as a REIT for the four subsequent taxable years. Also, each subsidiary REIT may be subject to certain local income taxes. The Operating Partnership has elected to treat several of its subsidiaries as TRSs, which are subject to federal, state and local income tax.
Earnings Per Share	Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing net income available to common shareholders, as adjusted for unallocated earnings, if any, of certain securities, by the weighted average number of common shares outstanding during the year. Diluted EPS reflects the potential dilution that could occur from common shares issuable in connection with awards under share-based compensation plans, including upon the exercise of stock options, and conversion of the noncontrolling interests in the Operating Partnership. Anti-dilutive shares are excluded from the calculation. Earnings Per Unit Basic EPS is computed by dividing net income available to common unitholders, as adjusted for unallocated earnings, if any, of certain securities issued by the Operating Partnership, by the weighted average number of common unit equivalents outstanding during the year. Diluted EPS reflects the potential dilution that could occur from shares issuable in connection with awards under share-based compensation plans, including upon the exercise of stock options. Anti-dilutive units are excluded from the calculation.
Share-Based Compensation Plans	Share-Based Compensation Plans The Parent Company maintains a shareholder-approved equity-incentive plan known as the Amended and Restated 1997 Long-Term Incentive Plan (the “1997 Plan”). The 1997 Plan is administered by the Compensation Committee of the Parent Company’s Board of Trustees. Under the 1997 Plan, the Compensation Committee is authorized to award equity and equity-based awards, including incentive stock options, non-qualified stock options, restricted shares and performance-based shares. On June 2, 2010, the Parent Company’s shareholders approved amendments to the 1997 Plan that, among other things, increased the number of common shares available for future awards under the 1997 Plan by 6,000,000 (of which 3,600,000 shares are available solely for options and share appreciation rights). As of December 31, 2016, 4,295,559 common shares remained available for future awards under the 1997 Plan (including 2,377,778 shares available solely for options and share appreciation rights). The Company incurred share-based compensation expense of $5.6 million during 2016, of which $1.0 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. The Company incurred share-based compensation expense of $7.3 million and $6.1 million during 2015 and 2014, of which $1.9 million and $1.7 million, respectively, were also capitalized. The expensed amounts are included in general and administrative expense on the Company’s consolidated income statement in the respective periods.
Comprehensive Income	Comprehensive Income Comprehensive income is recorded in accordance with the provisions of the accounting standard for comprehensive income. The accounting standard establishes standards for reporting comprehensive income and its components in the financial statements. Comprehensive income includes the effective portions of changes in the fair value of derivatives.
Accounting for Derivative Instruments and Hedging Activities	Accounting for Derivative Instruments and Hedging Activities The Company accounts for its derivative instruments and hedging activities in accordance with the accounting standard for derivative and hedging activities. The accounting standard requires the Company to measure every derivative instrument (including certain derivative instruments embedded in other contracts) at fair value and record them in the balance sheet as either an asset or liability. See disclosures below related to the accounting standard for fair value measurements and disclosures. For derivatives designated as cash flow hedges, the effective portions of changes in the fair value of the derivative are reported in other comprehensive income while the ineffective portions are recognized in earnings. The Company actively manages its ratio of fixed-to-floating rate debt. To manage its fixed and floating rate debt in a cost-effective manner, the Company, from time to time, enters into interest rate swap agreements as cash flow hedges, under which it agrees to exchange various combinations of fixed and/or variable interest rates based on agreed upon notional amounts.
Fair Value Measurements	Fair Value Measurements The Company estimates the fair value of its derivatives in accordance with the accounting standard for fair value measurements and disclosures. The accounting standard defines fair value as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. It also establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The standard describes three levels of inputs that may be used to measure fair value. 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. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. Non-financial assets and liabilities recorded at fair value on a non-recurring basis include non-financial assets and liabilities measured at fair value in a business combination and the impairment or disposal of long-lived assets measured at fair value. The Company periodically reviews its long-lived assets and equity method investments for other than temporary impairment. Any impairments recorded on equity method investments would be recorded at fair value on a non-recurring basis. The fair values assigned to the Company's purchase price allocations primarily utilize Level 3 inputs. The fair value assigned to the long-lived assets for which there was impairment recorded utilize Level 3 inputs.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In January 2017, the Financial Accounting Standards Board (FASB) issued guidance clarifying the definition of a business for purposes of determining when an acquisition (or disposition) should be accounted for as a business combination or an asset acquisition (or disposition) under the relevant accounting guidance. The amendments in the update provide a screen to determine when an integrated set of assets and activities (collectively referred to as a “set”) is not a business. The screen requires that when substantially all of the fair value of the gross assets acquired (or disposed of) is concentrated in a single identifiable asset or group of similar identifiable assets, the set is not a business. The screen reduces the number of transactions that need to be further evaluated. If the screen is not met, the amendments in the update require that: (i) to be considered a business, a set must include, at a minimum, an input and a substantive process that together significantly contribute to the ability to create output and (ii) remove the evaluation of whether a market participant could replace missing elements. The amendments provide a framework to assist entities in evaluating whether both an input and a substantive process are present. The framework includes two groups of criteria to consider that depend on whether a set has outputs. Although outputs are not required for a set to be a business, outputs generally are a key element of a business; therefore, the update provides more stringent criteria for sets without outputs. The guidance is applied prospectively and is effective for fiscal years beginning after December 15, 2017, including interim periods within those periods. Early adoption is permitted for transactions which have not been reported in financial statements that have been issued or made available for issuance. Properties acquired by the Company will most likely qualify as asset acquisitions under the new guidance compared to deemed business combinations under the previous accounting guidance. As a result, acquired property will be measured at cost, which generally includes transaction costs, the one year measurement period to determine the value of acquired contingencies does not apply to asset acquisitions and the disclosure requirements will change. In November 2016, the FASB issued guidance requiring 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. The guidance is effective for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019. In August 2016, the FASB issued guidance intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The areas addressed in the new guidance related to debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned and bank-owned life insurance policies, distributions received from equity method investments, beneficial interest in securitization transactions, and separately identifiable cash flows and application of the predominance principle. The standard is effective for financial statements issued for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, provided that all of the amendments are adopted in the same period. The guidance requires application using a retrospective transition method. The Company elected to early adopt this guidance resulting in a reclassification of debt extinguishment costs from operating activities to financing activities in the consolidated statements of cash flows for the year ended December 31, 2016. There was no other impact from the adoption of this guidance. In June 2016, the FASB issued guidance that changes how entities measure credit losses for most financial assets and certain other instruments that are not measured at fair value through net income. The guidance replaces the current incurred loss model with an expected loss approach, resulting in a more timely recognition of such losses. The guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted after December 2018. The Company is in the process of evaluating the impact of this new guidance and determined that the adoption of the guidance will have an impact on the Company’s estimation of its allowance for doubtful accounts. The Company has not quantified the impact that this guidance will have on its consolidated financial statements. In May 2016, the FASB issued guidance amending the revenue from contracts with customers standard issued in May 2014 (and not yet effective). The amendments are intended to address implementation issues that were raised by stakeholders and discussed by the Joint Transition Resource Group, and provide additional practical expedients on collectability, noncash consideration, presentation of sales tax and contract modifications and completed contracts at transition. • The Company does not believe this standard will have a material impact on its results of operations or financial condition, primarily because most of its revenue is from rental revenue. • The Company is analyzing its tenant reimbursement revenue to determine if the performance obligations set forth in the Company’s lease agreements will change the revenue recognition pattern. The Company does not expect this standard to have a material impact on the recognition of tenant reimbursement revenue. • The Company expects to identify similar performance obligations under this standard as compared with deliverables and separate units of account previously identified for leasing commissions, management fees and other sundry revenues. As a result, the Company expects the timing of its leasing commissions, management fees and other sundry revenues to remain the same. In March 2016, the FASB issued guidance intended to simplify various aspects related to how share-based payments are accounted for and presented in the financial statements. The new guidance allows for entities to make an entity-wide accounting policy election to either estimate the number of awards that are expected to vest or account for forfeitures when they occur. In addition, the guidance allows employers to withhold shares to satisfy minimum statutory tax withholding requirements up to the employees’ maximum individual tax rate without causing the award to be classified as a liability. The guidance also stipulates that cash paid by an employer to a taxing authority when directly withholding shares for tax-withholding purposes should be classified as a financing activity on the statement of cash flows. This guidance is effective for annual reporting periods beginning after December 15, 2016, and interim periods within that reporting period. Early adoption is permitted in any interim or annual period, with any adjustments reflected as of the beginning of the fiscal year of adoption. The Company has determined that this accounting guidance has no material impact on its consolidated financial statements. Also in March 2016, the FASB issued guidance clarifying that a novation of party to a derivative instrument, whereby one of the parties to a derivative instrument is replaced with another party, does not, in and of itself, require de-designation of that hedging relationship provided that all other hedge criteria continue to be met. The guidance is effective for financial statements issued for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years. An entity has an option to apply the amendments either on a prospective basis or on a modified retrospective basis. The Company has determined that this accounting guidance has no material impact on its consolidated financial statements. In February 2016, the FASB issued guidance 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 certain operating 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 are required to adopt the standard in accordance with public timeline. The Company anticipates the impact of ASC 842 will be similar the items described above. In August 2014, the FASB issued guidance regarding an Entity’s Ability to Continue as a Going Concern, which requires management to assess a company’s ability to continue as a going concern and to provide related footnote disclosures in certain circumstances. Before this new standard, there was minimal guidance in U.S. GAAP specific to going concern. Under the new standard, disclosures are required when conditions give rise to substantial doubt about a company’s ability to continue as a going concern within one year from the financial statement issuance date. The guidance is effective for annual reporting periods beginning after December 15, 2016, including interim periods within that reporting period, with early adoption permitted. The Company adopted the guidance during the fourth quarter of 2016, which had no impact on its consolidated financial statements. In May 2014, the FASB issued the Revenue from Contracts with Customers standard requiring revenue to be recognized in an amount that reflects the consideration expected to be received in exchange for goods and services. The standard requires the disclosure of sufficient quantitative and qualitative information for financial statement users to understand the nature, amount, timing and uncertainty of revenue and associated cash The Company anticipates the impact to its equity method investments will be similar.

Summary of Significant Accoun37

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Compensation Costs (Including Bonuses and Benefits) Capitalized	During the years ended December 31, 2016, 2015 and 2014, the Company’s internal direct construction costs are comprised entirely of capitalized salaries. The following table shows the amount of compensation costs (including bonuses and benefits) capitalized for the years presented (in thousands): December 31, 2016 2015 2014 Development $ 3,182 $ 2,641 $ 1,749 Redevelopment 144 221 184 Tenant Improvements 3,391 4,429 3,261 Total $ 6,717 $ 7,291 $ 5,194

Real Estate Investments (Tables

Real Estate Investments (Tables)	12 Months Ended
	Dec. 31, 2016
Real Estate Properties [Line Items]
Gross Carrying Value Of Company's Properties	As of December 31, 2016 and 2015 the gross carrying value of the Company’s Properties was as follows (in thousands): December 31, December 31, 2016 2015 Land $ 469,522 $ 513,268 Building and improvements 2,683,087 2,719,780 Tenant improvements 433,686 459,952 Operating properties 3,586,295 3,693,000 Assets held for sale - real estate investments (a) 73,591 794,588 Total $ 3,659,886 $ 4,487,588 (a) Real estate investments related to assets held for sale above represents gross real estate assets and does not include accumulated depreciation or other assets on the balance sheets of the properties held for sale. See Held for Sale section below.
Dispositions	The Company sold the following properties during the twelve-month period ended December 31, 2016 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) October 13, 2016 620, 640, 660 Allendale Road King of Prussia, PA 3 156,669 $ 12,800 $ 12,014 $ 2,382 September 1, 2016 1120 Executive Plaza Mt. Laurel, NJ 1 95,183 9,500 9,241 (18 ) (b) August 2, 2016 50 East Clementon Road Gibbsboro, NJ 1 3,080 1,100 1,011 (85 ) May 11, 2016 196/198 Van Buren Street (Herndon Metro Plaza I&II) Herndon, VA 2 197,225 44,500 43,412 (752 ) (c) February 5, 2016 2970 Market Street (Cira Square) Philadelphia, PA 1 862,692 354,000 350,150 115,828 February 4, 2016 Och-Ziff Portfolio Various (d) 58 3,924,783 398,100 353,971 (372 ) (e) Total Dispositions 66 5,239,632 $ 820,000 $ 769,799 $ 116,983 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs. (b) As of June 30, 2016, the Company determined that the sale of the property was probable and classified this property as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the property exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized a provision for impairment totaling approximately $1.8 million during the three-month period ended June 30, 2016. The fair value measurement was based on the pricing in the purchase and sale agreement for the sale of the property. As the pricing in the purchase and sale agreement is unobservable, the Company determined that the inputs utilized to determine fair value for this property falls within Level 3 in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, "Fair Value Measurements and Disclosures.” (c) During the three-month period ended March 31, 2016, the Company recognized a provision for impairment totaling approximately $7.4 million on the properties. See “Held for Use Impairment” section below. The loss on sale primarily relates to additional closing costs recognized at closing . (d) Exhibit 99.2 to the Company’s Current Report on Form 8-K filed on February 10, 2016 contains a complete list of the 58 properties disposed of in the transactions with Och-Ziff Capital Management Group LLC. See Note 4, "Investment in Unconsolidated Real Estate Ventures," (e) During the three-month period ended December 31, 2015, the Company recognized a provision for impairment totaling approximately $45.4 million. The loss on sale represents additional closing costs recognized at closing The Company sold the following land parcels during the twelve-month period ended December 31, 2016 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale (a) December 2, 2016 Oakland Lot B Oakland, CA 1 0.9 $ 13,750 $ 13,411 $ 9,039 August 19, 2016 Highlands Land Mt. Laurel, NJ 1 2.0 288 284 193 January 15, 2016 Greenhills Land Reading, PA 1 120.0 900 837 - (b) Total Dispositions 3 122.9 $ 14,938 $ 14,532 $ 9,232 (a) Gain on Sale is net of closing and other transaction related costs. (b) The carrying value of the land exceeded the fair value less the anticipated costs of sale as of December 31, 2015, therefore the Company recognized an impairment loss of $0.3 million during the three-month period ended December 31, 2015. There was no gain or loss recognized on the sale during 2016. The Company sold the following office properties, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2015 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain on Sale (a) December 31, 2015 5707 Southwest Parkway (Encino Trace) Austin, TX 2 320,000 $ 76,700 $ 50,158 $ 2,008 (b) December 29, 2015 Laurel Corporate Center Mt. Laurel, NJ 6 560,147 56,500 56,253 2,901 December 18, 2015 Carlsbad Properties Carlsbad, CA 3 196,075 30,400 29,568 - (c) December 18, 2015 751-761 Fifth Ave King of Prussia, PA 1 158,000 4,600 4,245 894 September 29, 2015 1000 Howard Boulevard Mt. Laurel, NJ 1 105,312 16,500 15,780 4,828 August 13, 2015 Bay Colony Office Park Wayne, PA 4 247,294 37,500 36,386 269 August 11, 2015 741 First Avenue King of Prussia, PA 1 77,184 4,900 4,640 372 June 10, 2015 100 Gateway Centre Parkway Richmond, VA 1 74,991 4,100 3,911 - (d) April 24, 2015 Christina & Delaware Corporate Centers Wilmington, DE 5 485,182 50,100 49,579 1,749 April 9, 2015 Lake Merritt Tower Oakland, CA 1 204,336 65,000 62,800 - (e) January 8, 2015 1000 Atrium Way / 457 Haddonfield Road (Atrium I / Libertyview) Mt. Laurel, NJ / Cherry Hill, NJ 2 221,405 28,300 26,778 8,981 Total Dispositions 27 2,649,926 $ 374,600 $ 340,098 $ 22,002 (f) (a) Gain on Sale is net of closing and other transaction related costs. (b) On December 31, 2015, the Company contributed two newly constructed four-story, Class A office buildings, commonly known as “Encino Trace,” containing an aggregate of approximately 320,000 square feet in Austin, Texas to one of its existing real estate ventures (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). When these two properties were contributed to the Austin Venture the Company had incurred a total of $76.7 million of development costs, representing the contribution value. The project is expected to cost $91.3 million with remaining costs fully funded by the Austin Venture. In conjunction with the contribution: (i) the Austin Venture obtained a $30.0 million mortgage loan; (ii) DRA contributed $25.1 million in net cash to the capital of the Austin Venture, including a $1.8 million working capital contribution; and (iii) the Austin Venture distributed $50.2 million to the Company and credited the Company with a $23.3 million capital contribution to the Austin Venture. In addition to the contribution of the properties, the Company also made a $1.8 million cash contribution to the Austin Venture for working capital. The Company recognized a $2.0 million gain on the contribution. Under the Encino Trace loan agreement the Austin Venture has the option, subject to certain leasing and loan-to-value requirements, to borrow an additional $29.7 million to fund tenant improvements and leasing commissions. (c) The Company recorded an impairment loss of $6.3 million for the Carlsbad office properties during the fourth quarter of 2015. As such, there was no gain at disposition for this property. (d) The Company recorded an impairment loss of $0.8 million for 100 Gateway Centre Parkway during the second quarter of 2015. As such, there was no gain at disposition for this property. (e) The Company recorded an impairment loss of $1.7 million for Lake Merritt Tower at March 31, 2015. As such, there was no gain at disposition for this property. Sales proceeds were deposited in escrow under Section 1031 of the Internal Revenue Code and applied to purchase the Broadmoor Austin portfolio. Refer to Broadmoor Austin Associates acquisition summary, above, for further details. (f) Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale. The Company sold the following land parcels, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2015 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) December 18, 2015 Two Christina Centre Wilmington, DE 1 1.6 $ 6,500 $ 5,986 $ - (b) September 1, 2015 7000 Midlantic Mt. Laurel, NJ 1 3.5 2,200 1,742 (169 ) August 31, 2015 Four Points Austin, TX 1 8.6 2,500 2,344 71 August 25, 2015 Two Kaiser Plaza Oakland, CA 1 1.0 11,100 11,016 3,117 Total Dispositions 4 14.7 $ 22,300 $ 21,088 $ 3,019 (a) Gain/(Loss) on sale includes closing and other transaction related costs. (b) The Company recorded an impairment loss of $0.3 million for Two Christina Centre during the fourth quarter of 2015. As such, there was no gain/(loss) at disposition for this land parcel. The Company sold the following office properties, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2014 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) October 24, 2014 100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Properties) Malvern, PA 5 279,934 $ 37,900 $ 37,156 $ 203 (b) September 30, 2014 1880 Campus Commons Drive (Campus Pointe) Reston, VA 1 172,943 42,500 41,476 4,698 April 3, 2014 11305 Four Points Drive (Four Points Centre) (c) Austin, TX 2 192,396 20,750 34,392 (255 ) (c) Total Dispositions 8 645,273 $ 101,150 $ 113,024 $ 4,646 (a) Gain/(Loss) on sale is net of closing and other transaction related costs. (b) During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties. (c) On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of approximately 192,396 net rentable square feet in Austin, Texas to an existing real estate venture (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). The Company contributed the properties to the Austin Venture at an agreed upon value of $41.5 million. In conjunction with the contribution: (i) the Austin Venture obtained a $29.0 million mortgage loan; (ii) DRA contributed $5.9 million in net cash to the capital of the Austin Venture; and (iii) the Austin Venture distributed $34.4 million to the Company and credited the Company with a $5.9 million capital contribution to the Austin Venture. The Company incurred a $0.2 million loss on the contribution, driven primarily by closing costs. The Company sold the following land parcels, in each case to unaffiliated third parties in arms’ length negotiations, during the twelve-month period ended December 31, 2014 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale (a) April 16, 2014 Westpoint II Land Dallas, TX 1 5.3 $ 1,600 $ 1,505 $ 12 March 27, 2014 Rob Roy Land Austin, TX 1 16.8 3,520 3,350 1,172 Total Dispositions 2 22.1 $ 5,120 $ 4,855 $ 1,184 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs.
Schedule of Purchase Price Allocation	The purchase price has been allocated as follows (in thousands): June 22, 2015 Building, land and improvements $ 163,271 Land inventory 6,045 Intangible assets acquired (a) 50,637 Below market lease liabilities assumed (b) (8,600 ) $ 211,353 Return of existing equity method investment (66,324 ) Gain on remeasurement (758 ) Net working capital assumed (450 ) Total cash payment at settlement $ 143,821 (a) Weighted average amortization period of 4.0 years. (b) Weighted average amortization period of 1.5 years
Schedule of Pro Forma Information	The supplemental pro forma operating data is not necessarily indicative of what the actual results of operations would have been assuming the transaction had been completed as set forth above, nor do they purport to represent the Company’s results of operations for future periods (in thousands, except for per share amounts). December 31, 2015 2014 Pro forma revenue $ 612,649 $ 618,119 Pro forma income (loss) from continuing operations (36,704 ) (7,371 ) Pro forma net income (loss) available to common shareholders (43,594 ) (13,669 ) Earnings (loss) per common share from continuing operations: Basic -- as reported $ (0.17 ) $ 0.04 Basic -- as pro forma $ (0.21 ) $ (0.04 ) Diluted -- as reported $ (0.17 ) $ 0.04 Diluted -- as pro forma $ (0.21 ) $ (0.04 ) Earnings (loss) per common share: Basic -- as reported $ (0.21 ) $ - Basic -- as pro forma $ (0.24 ) $ (0.08 ) Diluted -- as reported $ (0.21 ) $ - Diluted -- as pro forma $ (0.24 ) $ (0.08 )
Held for Sale Properties Included in Continuing Operations [Member]
Real Estate Properties [Line Items]
Summary of Properties Classified as Held for Sale but Which did not Meet the Criteria to be Classified within Discontinued Operations	The following is a summary of properties classified as held for sale at December 31, 2016 but which did not meet the criteria to be classified within discontinued operations at December 31, 2016 (in thousands): Held for Sale Properties Included in Continuing Operations December 31, 2016 Metropolitan D.C. - Office (a) Other Segment - Office (b) Other Segment - Land (c) Total ASSETS HELD FOR SALE Real estate investments: Operating properties $ 21,720 $ 51,871 $ - $ 73,591 Accumulated depreciation (11,935 ) (20,981 ) - (32,916 ) Operating real estate investments, net 9,785 30,890 - 40,675 Land held for development - - 1,043 1,043 Total real estate investments, net 9,785 30,890 1,043 41,718 Total assets held for sale, net $ 9,785 $ 30,890 $ 1,043 $ 41,718 LIABILITIES HELD FOR SALE Other liabilities $ 73 $ 8 $ - $ 81 Total liabilities held for sale $ 73 $ 8 $ - $ 81 (a) As of December 31, 2016, the Company determined that the sale of three office properties in the Metropolitan D.C. segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded their fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $3.0 million during the three-month period ended December 31, 2016. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 9.00% and 10.00%, respectively. The results were comparable to indicative pricing in the market (b) As The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 9.75% and 9.75%, respectively. The results were comparable to indicative pricing in the market. (c) As The fair value measurement was based on the pricing in the purchase and sale . The following is a summary of properties classified as held for sale but which did it not meet the criteria to be classified within discontinued operations at December 31, 2015 (in thousands): Held for Sale Properties Included in Continuing Operations December 31, 2015 Och-Ziff Properties (a) 2970 Market Street (b) Greenhills Land (c) Total ASSETS HELD FOR SALE Real estate investments: Operating properties $ 526,099 $ 268,489 $ - $ 794,588 Accumulated depreciation (179,092 ) (34,489 ) - (213,581 ) Operating real estate investments, net 347,007 234,000 - 581,007 Construction-in-progress 1,915 25 - 1,940 Land held for development - - 837 837 Total real estate investments, net 348,922 234,025 837 583,784 Intangible assets 581 - - 581 Total assets held for sale, net $ 349,503 $ 234,025 $ 837 $ 584,365 LIABILITIES HELD FOR SALE Acquired lease intangibles, net $ 192 $ - $ - $ 192 Other liabilities 1,959 - - 1,959 Total liabilities held for sale $ 2,151 $ - $ - $ 2,151 (a) On February 4, 2016, the Company disposed of its interests in 58 properties located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia segments in a series of related transactions with Och Ziff Real Estate. During the fourth quarter of 2015, significant provisions were agreed upon by both the Company and Och Ziff Real Estate and, as a result, the Company determined that the sale of the portfolio was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $45.4 million during the year ended December 31, 2015. The fair value measurement was based on the pricing in the purchase and sale agreement. As the significant inputs to the model are unobservable, the Company determined that the value determined for these real estate investments fall within Level 3 for fair value reporting. (b) On December 23, 2015 the Company entered into a purchase and sale agreement to dispose of its equity interests in the office property located at 2970 Market Street in Philadelphia commonly known as 30 th (c) On January 15, 2016, the Company sold the fee interest in a 120 acre land parcel located in Berks County, Pennsylvania for $0.9 million. As of December 31, 2015, the Company classified this land parcel as held for sale in accordance with the applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $0.3 million during the year ended December 31, 2015.

Investment in Unconsolidated 39

Investment in Unconsolidated Real Estate Ventures (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss)	The Company’s investment in Real Estate Ventures as of December 31, 2016 and 2015, and the Company’s share of the Real Estate Ventures’ income (loss) for the years ended December 31, 2016 and 2015 was as follows (in thousands): Carrying Amount Company's Share of Real Estate Venture Income (Loss) Real Estate Venture Debt at 100% Ownership Percentage (a) 2016 2015 2016 2015 2016 2015 Current Interest Rate Debt Maturity Office Properties Brandywine-AI Venture LLC (b) 50% $ 67,809 $ 50,760 $ (5,895 ) $ (229 ) $ 131,539 $ 132,717 3.96 % (c) DRA (G&I) Austin (d) 50% 52,886 60,427 (1,880 ) (1,235 ) 405,734 410,066 3.36 % (e) MAP Venture (f) 50% 20,893 - (4,218 ) - 180,800 - L+6.25% Feb 2018 Four Tower Bridge 65% 2,286 1,684 602 211 9,961 10,162 5.20 % Feb 2021 PJP VII 25% 980 872 233 211 4,956 5,621 L+2.65% Dec 2019 PJP II 30% 532 435 97 32 2,893 3,201 6.12 % Nov 2023 PJP VI 25% 142 45 97 151 7,652 7,918 6.08 % Apr 2023 1000 Chesterbrook Blvd. (g) - 1,895 160 117 - 23,610 PJP V (g) - 305 127 189 - 5,035 Invesco, L.P. (g) - - 261 349 - - Broadmoor Austin Associates (g) - - - (377 ) - - Coppell Associates (h) - (1,130 ) 12 84 - 15,515 Other HSRE-BDN I, LLC (d) 50% 21,228 15,003 843 (188 ) 105,000 95,562 L+2.25% Oct 2019 TB-BDN Plymouth Apartments 50% 12,450 12,338 119 (252 ) 53,967 50,964 L+1.70% Dec 2017 Brandywine 1919 Ventures (d) (i) 50% 27,462 29,086 (1,529 ) - 79,250 19,411 L+2.00% Oct 2018 Residence Inn Tower Bridge (g) - - - 367 - - Development Properties 4040 Wilson 50% 36,356 36,626 (270 ) (106 ) 1,004 - L+2.40% Mar 2019 51 N Street 70% 20,318 16,725 (114 ) - - - 1250 First Street Office 70% 17,304 14,312 (15 ) - - - Seven Tower Bridge 20% 685 491 (133 ) (135 ) 14,710 14,789 3.71 % (j) $ 281,331 $ 239,874 $ (11,503 ) $ (811 ) $ 997,466 $ 794,571 (a) Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable. (b) See “ Brandywine AI Venture: 3141 Fairview Park Drive” section below for information discussing activity that occurred during 2016 relating to this venture. (c) The debt for these properties is comprised of three fixed rate mortgages: (1) $37.9 million with a 4.40% fixed interest rate due January 1, 2019, (2) $27.1 million with a 4.65% fixed interest rate due January 1, 2022, and (3) $66.5 million with a 3.22% fixed interest rate due August 1, 2019, resulting in a time weighted average rate of 3.96%. (d) The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “ Evo at Cira South Venture” section below for further details on these transactions. (e) The debt for these properties includes seven mortgages: (1) $33.9 million that was swapped to a 1.59% fixed rate (or an all-in fixed rate of 3.52% incorporating the 1.93% spread) due November 1, 2018, (2) $54.7 million that was swapped to a 1.49% fixed rate (or an all-in rate of 3.19% incorporating the 1.70% spread) due October 15, 2018, (3) $137.0 million that was swapped to a 1.43% fixed rate (for an all-in fixed rate of 3.44% incorporating the 2.01% spread) due November 1, 2018, (4) $29.0 million with a 4.50% fixed interest rate due April 6, 2019, (5) $34.3 million with a 3.87% fixed interest rate due August 6, 2019, (6) $86.7 million that was swapped to a 1.36% fixed rate (or all-in fixed rate of 3.36% incorporating the 2.00% spread) due February 10, 2020, and (7) $30.0 million with a rate of LIBOR + 1.85% with a cap of 2.75% due January 1, 2021, resulting in a time and dollar weighted average rate of 3.36%. (f) In order to fulfill interest rate protection requirements, a LIBOR interest rate cap of 1.75% was purchased, effective February 3, 2016 and maturing February 9, 2018, for a notional amount of $200.8 million. There are three options to extend the maturity date of the debt for three successive terms, each year representing a separate option. (g) The Company liquidated its 25% ownership interest in the PJP V real estate venture on September 22, 2016. On June 30, 2016, the Company liquidated its 50% ownership interest in the venture known as 1000 Chesterbrook. The ownership interest in Invesco, L.P. was sold prior to December 31, 2015, and on August 19, 2016, the Company assigned its residual profits interest to the general partner of Invesco. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2016 dispositions. (h) Carrying amount represents the negative investment balance of the venture that was included in other liabilities as of December 31, 2015. The ownership interest in this venture was disposed of on January 29, 2016. (i) The stated rate for the construction loan is LIBOR + 2.00%. It is further reduced to 1.75% upon reaching 90% residential occupancy and commencement of the lease in the retail space. To fulfill interest rate protection requirements, an interest rate cap was purchased at 4.50%. (j) Comprised of two fixed rate mortgages totaling $8.0 million that mature on March 1, 2017 and accrue interest at a current rate of 7.00%, a $0.8 million 3.00% fixed rate loan through its September 1, 2025 maturity, a $2.0 million 4.00% fixed rate loan with interest only through its February 7, 2017 maturity and a $3.9 million 3.25% fixed rate loan with interest only beginning March 11, 2018 through its March 11, 2020 maturity, resulting in a time and dollar weighted average rate of 3.42%. The following is a summary of the financial position of the Real Estate Ventures as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Net property $ 1,483,067 $ 1,258,999 Other assets 231,972 158,672 Other liabilities 129,486 69,028 Debt, net 989,738 794,571 Equity 595,815 554,072 Company’s share of equity (Company’s basis) (a) (b) $ 281,331 $ 241,004 (a) 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. (b) Does not include the negative investment balance of one real estate venture totaling $1.1 million as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture on January 29, 2016. See “ Coppell Associates The following is a summary of results of operations of the Real Estate Ventures in which the Company had interests as of December 31, 2016, 2015 and 2014 (in thousands): Years Ended December 31, 2016 2015 2014 Revenue $ 214,452 $ 164,928 $ 147,236 Operating expenses (110,265 ) (70,136 ) (61,268 ) Provision for impairment (a) (10,476 ) - - Interest expense, net (43,283 ) (34,584 ) (36,511 ) Depreciation and amortization (85,738 ) (68,100 ) (57,109 ) Net loss (b) $ (35,310 ) $ (7,892 ) $ (7,652 ) Equity in loss of Real Estate Ventures $ (11,503 ) $ (811 ) $ (790 ) (a) During the year ended December 31, 2016, Brandywine - AI Venture LLC recorded a property level impairment charge of $10.4 million. See additional details in the “Station Square Impairment” disclosure below. (b) During the year ended December 31, 2016, there were $7.1 million of acquisition deal costs related to the formation of the MAP Venture.
Schedule of Maturities of Long-term Debt	As of December 31, 2016, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2017 $ 304,931 2018 331,601 2019 7,360 2020 86,978 2021 6,099 Thereafter 1,291,679 Total principal payments 2,028,648 Net unamortized premiums/(discounts) (7,439 ) Net deferred financing costs (8,097 ) Outstanding indebtedness $ 2,013,112
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Schedule of Maturities of Long-term Debt	As of December 31, 2016, the aggregate principal payments of recourse and non-recourse debt payable to third-parties are as follows (in thousands): 2017 $ 72,520 2018 485,847 2019 274,445 2020 92,261 2021 40,498 Thereafter 31,895 Total principal payments 997,466 Net deferred financing costs (7,728 ) Outstanding indebtedness $ 989,738

Deferred Costs (Assets) (Tables

Deferred Costs (Assets) (Tables)	12 Months Ended
	Dec. 31, 2016
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure	As of December 31, 2016 and 2015, the Company’s deferred costs (assets) were comprised of the following (in thousands): December 31, 2016 Total Cost Amortization Deferred Costs, net Leasing costs $ 146,135 $ (56,942 ) $ 89,193 Financing costs - Revolving Credit Facility 3,595 (1,446 ) 2,149 Total $ 149,730 $ (58,388 ) $ 91,342 December 31, 2015 Total Cost Accumulated Amortization Deferred Costs, net Leasing costs $ 165,741 $ (67,342 ) $ 98,399 Financing costs - Revolving Credit Facility 3,578 (558 ) 3,020 Total $ 169,319 $ (67,900 ) $ 101,419

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	As of December 31, 2016 and 2015, the Company’s intangible assets were comprised of the following (in thousands): December 31, 2016 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 142,889 $ (75,696 ) $ 67,193 Tenant relationship value 13,074 (10,167 ) 2,907 Above market leases acquired 4,718 (2,340 ) 2,378 Total intangible assets, net $ 160,681 $ (88,203 ) $ 72,478 Acquired lease intangibles, net: Below market leases acquired $ 37,579 $ (19,460 ) $ 18,119 December 31, 2015 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 161,276 $ (57,063 ) $ 104,213 Tenant relationship value 20,117 (15,580 ) 4,537 Above market leases acquired 5,333 (1,879 ) 3,454 186,726 (74,522 ) 112,204 Assets held for sale (2,854 ) 2,273 (581 ) Total intangible assets, net $ 183,872 $ (72,249 ) $ 111,623 Acquired lease intangibles, net: Below market leases acquired $ 50,025 $ (24,178 ) $ 25,847 Assets held for sale (1,069 ) 877 (192 ) Total acquired lease intangibles, net $ 48,956 $ (23,301 ) $ 25,655
Summary of Amortization for Intangible Assets and Liabilities	As of December 31, 2016, the Company’s annual amortization for its intangible assets/liabilities, assuming no early lease terminations, are as follows (dollars in thousands): Assets Liabilities 2017 $ 19,663 $ 3,323 2018 11,754 2,196 2019 10,536 1,885 2020 8,457 1,337 2021 5,971 807 Thereafter 16,097 8,571 Total $ 72,478 $ 18,119

Debt Obligations (Tables)

Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Consolidated debt obligations	The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at December 31, 2016 and 2015 (in thousands): December 31, 2016 December 31, 2015 Effective Interest Rate Maturity Date MORTGAGE DEBT: 3141 Fairview Park Drive (a) $ - $ 20,838 4.25 % Jan 2017 Two Logan Square 86,012 86,886 3.98 % (b) May 2020 One Commerce Square 127,026 130,000 3.64 % (c) Apr 2023 Two Commerce Square 112,000 112,000 4.51 % (d) Apr 2023 IRS Philadelphia Campus (e) - 177,425 7.00 % Sep 2030 Cira South Garage (e) - 35,546 7.12 % Sep 2030 Principal balance outstanding 325,038 562,695 Plus: fair market value premium (discount), net (2,761 ) (3,198 ) Less: deferred financing costs (728 ) (13,744 ) Mortgage indebtedness $ 321,549 $ 545,753 UNSECURED DEBT Seven-Year Term Loan - Swapped to fixed $ 250,000 $ 250,000 3.72 % Oct 2022 $250.0M 6.00% Guaranteed Notes due 2016 (f) - 149,919 5.95 % Apr 2016 $300.0M 5.70% Guaranteed Notes due 2017 300,000 300,000 5.68 % May 2017 $325.0M 4.95% Guaranteed Notes due 2018 325,000 325,000 5.13 % Apr 2018 $250.0M 3.95% Guaranteed Notes due 2023 250,000 250,000 4.02 % Feb 2023 $250.0M 4.10% Guaranteed Notes due 2024 250,000 250,000 4.33 % Oct 2024 $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 2.75 % Mar 2035 Indenture IB (Preferred Trust I) 25,774 25,774 3.30 % Apr 2035 Indenture II (Preferred Trust II) 25,774 25,774 3.09 % Jul 2035 Principal balance outstanding 1,703,610 1,853,529 Plus: original issue premium (discount), net (4,678 ) (5,714 ) Less: deferred financing costs (7,369 ) (8,851 ) Total unsecured indebtedness $ 1,691,563 $ 1,838,964 Total Debt Obligations $ 2,013,112 $ 2,384,717 (a) On August 31, 2016, the Company deconsolidated 3141 Fairview Park Drive and began accounting for it under the equity method of accounting as part of Brandywine - AI Venture LLC, an unconsolidated real estate venture in which the Company holds At December 31, 2015, this balance represented the full debt amount of the property, as it was consolidated at that time. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further details. (b) On April 7, 2016, the Company closed on an $86.9 million first mortgage financing on Two Logan Square, a 708,844-square foot office property located in Philadelphia, Pennsylvania. Proceeds of the loan were used to repay, without penalty, the $86.6 million principal balance of the former Two Logan Square first mortgage loan, which had a 7.57% effective interest rate. (c) This loan was assumed upon acquisition of the related properties on December 19, 2013. On December 29, 2015, the Company refinanced the debt increasing the principal balance to $130.0 million and extended the term from the scheduled maturity from January 6, 2016 to April 5, 2023. The effective interest rate as of December 31, 2015 was 3.64%. A default under this loan will also constitute a default under the loan outstanding on Two Commerce Square. This loan is also secured by a lien on Two Commerce Square. (d) This loan was assumed upon acquisition of the related property on December 19, 2013. The interest rate reflects the market rate at the time of acquisition. A default under this loan will also constitute a default under the loan outstanding on One Commerce Square. This loan is also secured by a lien on One Commerce Square. (e) On January 14, 2016, the Company funded $265.8 million to prepay two mortgage loans, consisting of $176.9 million of principal repayment, $44.5 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness on the office property located at 2970 Market Street in Philadelphia, Pennsylvania commonly known as 30 th Street Main Post Office (“Cira Square”), ahead of its scheduled maturity date of September 10, 2030. Also on January 14, 2016, the Company funded $44.4 million, consisting of $35.5 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness of a 1,662 parking space facility located in Philadelphia, Pennsylvania commonly known as (“Cira South Garage”), ahead of its scheduled maturity date of September 10, 2030. These repayments were financed with $195.0 million of funds available under the Credit Facility with the remaining balance funded through available cash balances. The Company recognized a $66.6 million loss on extinguishment of debt, consisting of the prepayment charges along with $10.8 million and $2.4 million related to non-cash charges for deferred financing costs for Cira Square and Cira South Garage, respectively. (f) On April 1, 2016, the entire principal balance of the unsecured 6.00% Guaranteed Notes was repaid upon maturity. Available cash balances were used to fund the repayment of the unsecured notes.
Summary of debt repurchases	The following table provides additional information on the Company’s repurchase of $376.2 million in aggregate principal amount of its outstanding unsecured notes (consisting of the 2014 Notes and 2015 Notes, as indicated above) during the twelve months ended December 31, 2014 (in thousands): Notes Principal Repurchase Amount (a) Loss on Early Extinguishment of Debt (b) Acceleration of Deferred Financing 2014 5.40% Notes $ 218,549 $ 219,404 $ (855 ) $ 9 2015 7.50% Notes 157,625 164,364 (6,739 ) 143 $ 376,174 $ 383,768 $ (7,594 ) $ 152 (a) Includes cash losses with respect to redemption of debt. (b) Includes unamortized balance of the original issue discount.
Schedule of Maturities of Long-term Debt	As of December 31, 2016, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2017 $ 304,931 2018 331,601 2019 7,360 2020 86,978 2021 6,099 Thereafter 1,291,679 Total principal payments 2,028,648 Net unamortized premiums/(discounts) (7,439 ) Net deferred financing costs (8,097 ) Outstanding indebtedness $ 2,013,112

Fair Value of Financial Instr43

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
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): December 31, 2016 December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value Unsecured notes payable $ 1,364,854 $ 1,372,758 $ 1,512,554 $ 1,529,346 Variable rate debt $ 326,709 $ 307,510 $ 326,410 $ 305,522 Mortgage notes payable $ 321,549 $ 328,853 $ 545,753 $ 597,377 Note receivable (a) $ 3,380 $ 3,717 $ - $ - (a) The inputs to originate the loan 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. See Note 2, “Significant Accounting Policies,” for further information regarding the note origination.

Risk Management and Use of De44

Risk Management and Use of Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 and December 31, 2015. 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 liabilities on the Company’s consolidated balance sheets). Hedge Product Hedge Type Designation Notional Amount Strike Trade Date Maturity Date Fair value 12/31/2016 12/31/2015 12/31/2016 12/31/2015 Assets Swap Interest Rate Cash Flow (a) $ 250,000 $ 250,000 3.718 % October 8, 2015 October 8, 2022 $ 3,733 $ 1,884 Liabilities Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 (300 ) (531 ) Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 (214 ) (388 ) Swap Interest Rate Cash Flow (a) 27,062 27,062 2.750 % December 21, 2011 September 30, 2017 (83 ) (201 ) $ 328,610 $ 328,610 (a) Hedging unsecured variable rate debt.

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2016
Dispositions	The Company sold the following properties during the twelve-month period ended December 31, 2016 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) October 13, 2016 620, 640, 660 Allendale Road King of Prussia, PA 3 156,669 $ 12,800 $ 12,014 $ 2,382 September 1, 2016 1120 Executive Plaza Mt. Laurel, NJ 1 95,183 9,500 9,241 (18 ) (b) August 2, 2016 50 East Clementon Road Gibbsboro, NJ 1 3,080 1,100 1,011 (85 ) May 11, 2016 196/198 Van Buren Street (Herndon Metro Plaza I&II) Herndon, VA 2 197,225 44,500 43,412 (752 ) (c) February 5, 2016 2970 Market Street (Cira Square) Philadelphia, PA 1 862,692 354,000 350,150 115,828 February 4, 2016 Och-Ziff Portfolio Various (d) 58 3,924,783 398,100 353,971 (372 ) (e) Total Dispositions 66 5,239,632 $ 820,000 $ 769,799 $ 116,983 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs. (b) As of June 30, 2016, the Company determined that the sale of the property was probable and classified this property as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the property exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized a provision for impairment totaling approximately $1.8 million during the three-month period ended June 30, 2016. The fair value measurement was based on the pricing in the purchase and sale agreement for the sale of the property. As the pricing in the purchase and sale agreement is unobservable, the Company determined that the inputs utilized to determine fair value for this property falls within Level 3 in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, "Fair Value Measurements and Disclosures.” (c) During the three-month period ended March 31, 2016, the Company recognized a provision for impairment totaling approximately $7.4 million on the properties. See “Held for Use Impairment” section below. The loss on sale primarily relates to additional closing costs recognized at closing . (d) Exhibit 99.2 to the Company’s Current Report on Form 8-K filed on February 10, 2016 contains a complete list of the 58 properties disposed of in the transactions with Och-Ziff Capital Management Group LLC. See Note 4, "Investment in Unconsolidated Real Estate Ventures," (e) During the three-month period ended December 31, 2015, the Company recognized a provision for impairment totaling approximately $45.4 million. The loss on sale represents additional closing costs recognized at closing The Company sold the following land parcels during the twelve-month period ended December 31, 2016 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale (a) December 2, 2016 Oakland Lot B Oakland, CA 1 0.9 $ 13,750 $ 13,411 $ 9,039 August 19, 2016 Highlands Land Mt. Laurel, NJ 1 2.0 288 284 193 January 15, 2016 Greenhills Land Reading, PA 1 120.0 900 837 - (b) Total Dispositions 3 122.9 $ 14,938 $ 14,532 $ 9,232 (a) Gain on Sale is net of closing and other transaction related costs. (b) The carrying value of the land exceeded the fair value less the anticipated costs of sale as of December 31, 2015, therefore the Company recognized an impairment loss of $0.3 million during the three-month period ended December 31, 2015. There was no gain or loss recognized on the sale during 2016. The Company sold the following office properties, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2015 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain on Sale (a) December 31, 2015 5707 Southwest Parkway (Encino Trace) Austin, TX 2 320,000 $ 76,700 $ 50,158 $ 2,008 (b) December 29, 2015 Laurel Corporate Center Mt. Laurel, NJ 6 560,147 56,500 56,253 2,901 December 18, 2015 Carlsbad Properties Carlsbad, CA 3 196,075 30,400 29,568 - (c) December 18, 2015 751-761 Fifth Ave King of Prussia, PA 1 158,000 4,600 4,245 894 September 29, 2015 1000 Howard Boulevard Mt. Laurel, NJ 1 105,312 16,500 15,780 4,828 August 13, 2015 Bay Colony Office Park Wayne, PA 4 247,294 37,500 36,386 269 August 11, 2015 741 First Avenue King of Prussia, PA 1 77,184 4,900 4,640 372 June 10, 2015 100 Gateway Centre Parkway Richmond, VA 1 74,991 4,100 3,911 - (d) April 24, 2015 Christina & Delaware Corporate Centers Wilmington, DE 5 485,182 50,100 49,579 1,749 April 9, 2015 Lake Merritt Tower Oakland, CA 1 204,336 65,000 62,800 - (e) January 8, 2015 1000 Atrium Way / 457 Haddonfield Road (Atrium I / Libertyview) Mt. Laurel, NJ / Cherry Hill, NJ 2 221,405 28,300 26,778 8,981 Total Dispositions 27 2,649,926 $ 374,600 $ 340,098 $ 22,002 (f) (a) Gain on Sale is net of closing and other transaction related costs. (b) On December 31, 2015, the Company contributed two newly constructed four-story, Class A office buildings, commonly known as “Encino Trace,” containing an aggregate of approximately 320,000 square feet in Austin, Texas to one of its existing real estate ventures (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). When these two properties were contributed to the Austin Venture the Company had incurred a total of $76.7 million of development costs, representing the contribution value. The project is expected to cost $91.3 million with remaining costs fully funded by the Austin Venture. In conjunction with the contribution: (i) the Austin Venture obtained a $30.0 million mortgage loan; (ii) DRA contributed $25.1 million in net cash to the capital of the Austin Venture, including a $1.8 million working capital contribution; and (iii) the Austin Venture distributed $50.2 million to the Company and credited the Company with a $23.3 million capital contribution to the Austin Venture. In addition to the contribution of the properties, the Company also made a $1.8 million cash contribution to the Austin Venture for working capital. The Company recognized a $2.0 million gain on the contribution. Under the Encino Trace loan agreement the Austin Venture has the option, subject to certain leasing and loan-to-value requirements, to borrow an additional $29.7 million to fund tenant improvements and leasing commissions. (c) The Company recorded an impairment loss of $6.3 million for the Carlsbad office properties during the fourth quarter of 2015. As such, there was no gain at disposition for this property. (d) The Company recorded an impairment loss of $0.8 million for 100 Gateway Centre Parkway during the second quarter of 2015. As such, there was no gain at disposition for this property. (e) The Company recorded an impairment loss of $1.7 million for Lake Merritt Tower at March 31, 2015. As such, there was no gain at disposition for this property. Sales proceeds were deposited in escrow under Section 1031 of the Internal Revenue Code and applied to purchase the Broadmoor Austin portfolio. Refer to Broadmoor Austin Associates acquisition summary, above, for further details. (f) Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale. The Company sold the following land parcels, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2015 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) December 18, 2015 Two Christina Centre Wilmington, DE 1 1.6 $ 6,500 $ 5,986 $ - (b) September 1, 2015 7000 Midlantic Mt. Laurel, NJ 1 3.5 2,200 1,742 (169 ) August 31, 2015 Four Points Austin, TX 1 8.6 2,500 2,344 71 August 25, 2015 Two Kaiser Plaza Oakland, CA 1 1.0 11,100 11,016 3,117 Total Dispositions 4 14.7 $ 22,300 $ 21,088 $ 3,019 (a) Gain/(Loss) on sale includes closing and other transaction related costs. (b) The Company recorded an impairment loss of $0.3 million for Two Christina Centre during the fourth quarter of 2015. As such, there was no gain/(loss) at disposition for this land parcel. The Company sold the following office properties, in each case to unaffiliated third parties in arms’ length transactions, during the twelve-month period ended December 31, 2014 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Properties Rentable Square Feet Sales Price Net Proceeds on Sale Gain/(Loss) on Sale (a) October 24, 2014 100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Properties) Malvern, PA 5 279,934 $ 37,900 $ 37,156 $ 203 (b) September 30, 2014 1880 Campus Commons Drive (Campus Pointe) Reston, VA 1 172,943 42,500 41,476 4,698 April 3, 2014 11305 Four Points Drive (Four Points Centre) (c) Austin, TX 2 192,396 20,750 34,392 (255 ) (c) Total Dispositions 8 645,273 $ 101,150 $ 113,024 $ 4,646 (a) Gain/(Loss) on sale is net of closing and other transaction related costs. (b) During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties. (c) On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of approximately 192,396 net rentable square feet in Austin, Texas to an existing real estate venture (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). The Company contributed the properties to the Austin Venture at an agreed upon value of $41.5 million. In conjunction with the contribution: (i) the Austin Venture obtained a $29.0 million mortgage loan; (ii) DRA contributed $5.9 million in net cash to the capital of the Austin Venture; and (iii) the Austin Venture distributed $34.4 million to the Company and credited the Company with a $5.9 million capital contribution to the Austin Venture. The Company incurred a $0.2 million loss on the contribution, driven primarily by closing costs. The Company sold the following land parcels, in each case to unaffiliated third parties in arms’ length negotiations, during the twelve-month period ended December 31, 2014 (dollars in thousands): Disposition Date Property/Portfolio Name Location Number of Parcels Acres Sales Price Net Proceeds on Sale Gain on Sale (a) April 16, 2014 Westpoint II Land Dallas, TX 1 5.3 $ 1,600 $ 1,505 $ 12 March 27, 2014 Rob Roy Land Austin, TX 1 16.8 3,520 3,350 1,172 Total Dispositions 2 22.1 $ 5,120 $ 4,855 $ 1,184 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs.
Discontinued Operations [Member]
Dispositions	The following table summarizes revenue and expense information for the properties sold which qualify for discontinued operations reporting since January 1, 2014 (in thousands): Years ended December 31, 2014 Revenue: Rents $ - Tenant reimbursements 26 Other - Total revenue 26 Expenses: Property operating expenses 8 Real estate taxes - Depreciation and amortization - Total operating expenses 8 Other income: Interest income - Income from discontinued operations before gain on sale of interests in real estate 18 Net gain on disposition of discontinued operations 900 Income from discontinued operations $ 918

Beneficiaries Equity of the P46

Beneficiaries Equity of the Parent Company (Tables)	12 Months Ended
	Dec. 31, 2016
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): Year ended December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ 40,501 $ 40,501 $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 Net (income) loss from continuing operations attributable to non-controlling interests (310 ) (310 ) 339 339 43 43 Nonforfeitable dividends allocated to unvested restricted shareholders (341 ) (341 ) (329 ) (329 ) (349 ) (349 ) Preferred share dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Income (loss) from continuing operations available to common shareholders 32,950 32,950 (37,630 ) (37,630 ) (1,182 ) (1,182 ) Income from discontinued operations - - - - 908 908 Net income (loss) attributable to common shareholders $ 32,950 $ 32,950 $ (37,630 ) $ (37,630 ) $ (274 ) $ (274 ) Denominator Weighted-average shares outstanding 175,018,163 175,018,163 178,162,160 178,162,160 166,202,649 166,202,649 Contingent securities/Share based compensation - 992,651 - - - - Weighted-average shares outstanding 175,018,163 176,010,814 178,162,160 178,162,160 166,202,649 166,202,649 Earnings (loss) per Common Share: Income (loss) from continuing operations attributable to common shareholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ (0.01 ) $ (0.01 ) Discontinued operations attributable to common shareholders - - - - 0.01 0.01 Net income (loss) attributable to common shareholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ - $ -

Partners Equity of the Operat47

Partners Equity of the Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2016
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): Year ended December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ 40,501 $ 40,501 $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 Net (income) loss from continuing operations attributable to non-controlling interests (310 ) (310 ) 339 339 43 43 Nonforfeitable dividends allocated to unvested restricted shareholders (341 ) (341 ) (329 ) (329 ) (349 ) (349 ) Preferred share dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Income (loss) from continuing operations available to common shareholders 32,950 32,950 (37,630 ) (37,630 ) (1,182 ) (1,182 ) Income from discontinued operations - - - - 908 908 Net income (loss) attributable to common shareholders $ 32,950 $ 32,950 $ (37,630 ) $ (37,630 ) $ (274 ) $ (274 ) Denominator Weighted-average shares outstanding 175,018,163 175,018,163 178,162,160 178,162,160 166,202,649 166,202,649 Contingent securities/Share based compensation - 992,651 - - - - Weighted-average shares outstanding 175,018,163 176,010,814 178,162,160 178,162,160 166,202,649 166,202,649 Earnings (loss) per Common Share: Income (loss) from continuing operations attributable to common shareholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ (0.01 ) $ (0.01 ) Discontinued operations attributable to common shareholders - - - - 0.01 0.01 Net income (loss) attributable to common shareholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ - $ -
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): Year ended December 31, 2016 2015 2014 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ 40,501 $ 40,501 $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 Nonforfeitable dividends allocated to unvested restricted unitholders (341 ) (341 ) (329 ) (329 ) (349 ) (349 ) Preferred unit dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Net (income) loss attributable to non-controlling interests (15 ) (15 ) 3 3 44 44 Income (loss) from continuing operations available to common unitholders 33,245 33,245 (37,966 ) (37,966 ) (1,181 ) (1,181 ) Discontinued operations attributable to common unitholders - - - - 918 918 Net income (loss) attributable to common unitholders $ 33,245 $ 33,245 $ (37,966 ) $ (37,966 ) $ (263 ) $ (263 ) Denominator Weighted-average units outstanding 176,523,800 176,523,800 179,697,262 179,697,262 167,942,246 167,942,246 Contingent securities/Share based compensation - 992,651 - - - - Total weighted-average units outstanding 176,523,800 177,516,451 179,697,262 179,697,262 167,942,246 167,942,246 Earnings (loss) per Common Partnership Unit: Income (loss) from continuing operations attributable to common unitholders 0.19 0.19 (0.21 ) (0.21 ) (0.01 ) (0.01 ) Discontinued operations attributable to common unitholders - - - - 0.01 0.01 Net income (loss) attributable to common unitholders $ 0.19 $ 0.19 $ (0.21 ) $ (0.21 ) $ - $ -

Share Based Compensation, 40148

Share Based Compensation, 401(k) Plan and Deferred Compensation (Tables)	12 Months Ended
	Dec. 31, 2016
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Option Activity	Option activity as of December 31, 2016 and changes during the year-ended December 31, 2016 were as follows: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2016 2,624,067 $ 15.47 3.12 Exercised (111,209 ) $ 11.56 $ 347,881 Forfeited/Expired (135,080 ) $ 20.61 Outstanding at December 31, 2016 2,377,778 $ 15.36 2.15 $ 8,003,403 Vested/Exercisable at December 31, 2016 2,377,778 $ 15.36 2.15 $ 8,003,403
Company's Restricted Share Activity	The following table summarizes the Company’s restricted share activity during the year-ended December 31, 2016: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2016 506,147 $ 14.50 $ 6,913,968 Granted 227,845 12.92 2,937,771 Vested (195,140 ) 13.50 2,813,799 Forfeited (50,248 ) 15.03 Non-vested at December 31, 2016 488,604 $ 14.10 $ 8,066,852
Schedule of Restricted Performance Share Units Plan	The table below presents certain information as to unvested RPSU awards. RPSU Grant 3/11/2014 3/12/2014 2/23/2015 2/22/2016 Total (Amounts below in shares, unless otherwise noted) Non-vested at January 1, 2016 123,155 61,720 179,392 - 364,267 Units Granted - - - 231,388 231,388 Units Cancelled (30,724 ) - (31,803 ) - (62,527 ) Non-vested at December 31, 2016 92,431 61,720 147,589 231,388 533,128 Measurement Period Commencement Date 1/1/2014 1/1/2014 1/1/2015 1/1/2016 Measurement Period End Date 12/31/2016 12/31/2016 12/31/2017 12/31/2018 Units Granted 134,284 61,720 186,395 231,388 Fair Value of Units on Grant Date (in thousands) $ 2,624 $ 1,255 $ 3,933 $ 3,558

Distributions (Tables)

Distributions (Tables)	12 Months Ended
	Dec. 31, 2016
Distributions [Abstract]
Schedule of Dividends Payable	The following table provides the tax characteristics of the 2016, 2015 and 2014 distributions paid: Years ended December 31, 2016 2015 2014 (in thousands, except per share amounts) Common Share Distributions: Ordinary income $ - $ 0.36 $ 0.41 Capital gain 0.62 0.14 0.02 Non-taxable distributions - 0.10 0.17 Distributions per share $ 0.62 $ 0.60 $ 0.60 Percentage classified as ordinary income 0.00 % 59.10 % 69.00 % Percentage classified as capital gain 100.00 % 23.50 % 3.30 % Percentage classified as non-taxable distribution 0.00 % 17.40 % 27.70 % Preferred Share Distributions: Total distributions paid $ 6,900 $ 6,900 $ 6,900 Percentage classified as ordinary income 100.00 % 100.00 % 100.00 %

Accumulated Other Comprehensi50

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss)	The following table details the components of accumulated other comprehensive income (loss) of the Parent Company and the Operating Partnership as of and for the three years ended December 31, 2016 (in thousands): Parent Company Cash Flow Hedges Balance at January 1, 2014 $ (2,995 ) Change during year (1,190 ) Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests 18 Settlement of interest rate swaps (828 ) Reclassification adjustments for (gains)/losses reclassified into operations 388 Balance at December 31, 2014 $ (4,607 ) Change during year (1,010 ) Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests 5 Reclassification adjustments for (gains)/losses reclassified into operations 420 Balance at December 31, 2015 $ (5,192 ) Change during year 2,371 Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests (28 ) Reclassification adjustments for (gains)/losses reclassified into operations 1,104 Balance at December 31, 2016 $ (1,745 ) Operating Partnership Cash Flow Hedges Balance at January 1, 2014 $ (3,377 ) Change during year (1,190 ) Settlement of interest rate swaps (828 ) Reclassification adjustments for (gains)/losses reclassified into operations 388 Balance at December 31, 2014 $ (5,007 ) Change during year (1,010 ) Reclassification adjustments for (gains)/losses reclassified into operations 420 Balance at December 31, 2015 $ (5,597 ) Change during year 2,371 Reclassification adjustments for (gains)/losses reclassified into operations 1,104 Balance at December 31, 2016 $ (2,122 )

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
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 for the three years ended December 31, 2016, 2015 and 2014 (in thousands): Real estate investments, at cost: December 31, 2016 December 31, 2015 December 31, 2014 Philadelphia CBD $ 1,320,974 $ 1,157,667 $ 1,338,655 Pennsylvania Suburbs 1,005,446 1,019,280 1,178,470 Metropolitan Washington, D.C. 975,987 1,129,206 1,183,652 Austin, Texas 146,794 164,518 - Other (a) 137,094 222,329 902,915 $ 3,586,295 $ 3,693,000 $ 4,603,692 Assets held for sale (b), (c) 73,591 794,588 27,436 Operating Properties $ 3,659,886 $ 4,487,588 $ 4,631,128 Corporate Construction-in-progress $ 297,462 $ 268,983 $ 201,360 Land inventory $ 150,970 $ 130,479 $ 90,603 (a) As a result of the Och-Ziff Sale that occurred on February 4, 2016, the Company narrowed its segments to five segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C. and (4) Austin, Texas and (5) Other. The Och-Ziff Sale disposed of the entire Richmond, Virginia segment. Subsequent to the Och-Ziff Sale, the segments previously defined as New Jersey/Delaware and California are now being managed as a consolidated segment entitled “Other,” as these geographies no longer provide a significant revenue contribution. Accordingly, the chief operating decision maker revised the management structure, reallocated resources, and is assessing business operations of the five segments as of January 1, 2016. (b) As of December 31, 2015, 2970 Market Street was classified as held for sale on the consolidated balance sheets. The property was sold on February 5, 2016. See Note 21, " Subsequent Events ," for further information. The sale is not classified as a significant disposition under the accounting guidance for discontinued operations. (c) As of December 31, 2015, the 58 properties associated with the series of related transactions with Och-Ziff Real Estate were classified as held for sale on the consolidated balance sheets. On February 4, 2016, the Company completed a series of transactions, resulting in the disposition of the properties. See Note 3, “Real Estate Investments,” for further information regarding the disposition. Additionally, as of December 31, 2016, the Company categorized three office properties located in the Metropolitan Washington, D.C. segment and two properties in the Other segment as held for sale in accordance with applicable accounting standards for long lived assets. See Note 3, “Real Estate Investments,” for further information. None of the above aforementioned sales or properties classified as held for sale are considered significant dispositions under the accounting guidance for discontinued operations. Years ended December 31, 2016 2015 2014 Total revenue Operating expenses (a) Net operating income Total revenue Operating expenses (a) Net operating income Total revenue Operating expenses (a) Net Operating income Philadelphia CBD $ 200,245 $ (78,708 ) $ 121,537 $ 209,298 $ (77,352 ) $ 131,946 $ 201,809 $ (75,262 ) $ 126,547 Pennsylvania Suburbs 144,338 (49,208 ) 95,130 158,398 (57,319 ) 101,079 160,630 (55,062 ) 105,568 Metropolitan Washington, D.C. 99,781 (39,036 ) 60,745 110,657 (44,294 ) 66,363 113,834 (43,399 ) 70,435 Austin, Texas (b) 34,585 (13,222 ) 21,363 20,910 (8,010 ) 12,900 5,610 (3,223 ) 2,387 Other 39,359 (23,204 ) 16,155 98,799 (49,604 ) 49,195 113,971 (57,214 ) 56,757 Corporate 7,155 (6,070 ) 1,085 4,569 (1,508 ) 3,061 1,128 (1,805 ) (677 ) Operating Properties $ 525,463 $ (209,448 ) $ 316,015 $ 602,631 $ (238,087 ) $ 364,544 $ 596,982 $ (235,965 ) $ 361,017 (a) Includes property operating expense, real estate taxes and third party management expense. (b) On June 22, 2015 the Company acquired the remaining 50.0% of the common interest in Broadmoor Austin Associates. As such, the Company has seven wholly owned properties in its Austin, Texas business segment at December 31, 2016. In addition, net operating income for the years ended December 31, 2016 and 2015 includes management fees and related expenses for services provided by the Company to the Austin Venture. "Real Estate Investments," Unconsolidated real estate ventures: Investment in real estate ventures, at equity Equity in income (loss) of real estate ventures As of Years ended December 31, December 31, 2016 December 31, 2015 December 31, 2014 2016 2015 2014 Philadelphia CBD $ 48,691 $ 44,089 $ 27,137 $ (686 ) $ (188 ) $ 46 Pennsylvania Suburbs 15,421 16,408 17,385 748 310 (777 ) Metropolitan Washington, D.C. (a) 141,786 118,422 73,127 (6,293 ) (336 ) (317 ) MAP Venture (b) 20,893 - - (4,218 ) - - Other (c) 1,654 1,657 1,574 814 930 1,338 Austin, Texas (d) 52,886 60,428 105,781 (1,868 ) (1,527 ) (1,080 ) Total $ 281,331 $ 241,004 $ 225,004 $ (11,503 ) $ (811 ) $ (790 ) (a) On August 31, 2016, the Company terminated its lease for the regional management and leasing office at 3141 Fairview Park Drive, located in Falls Church, Virginia. Accordingly, the Company no longer has any continuing involvement with 3141 Fairview Park Drive and recorded the partial sale under the full accrual method of accounting. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further information. (b) 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. See Note 4 “ Investment in Unconsolidated Real Estate Ventures, ” for further information. 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. (c) See footnote (a) to the “Real estate investments, at cost” table above for further information regarding this segment. (d) Investment in real estate ventures does not include the $1.1 million negative investment balance in one real estate venture as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture during the three-month period ended March 31, 2016. See Note 4, " Investment in Unconsolidated Real Estate Ventures ," for further information. The decrease to the Company’s investment balance primarily relates to distributions from the G&I VII Austin Office LLC real estate venture.
Reconciliation of Consolidated NOI to Consolidated Net Income (Loss)	The following is a reconciliation of consolidated NOI to consolidated net income (loss), as defined by GAAP: Years Ended December 31, 2016 2015 2014 Consolidated net operating income $ 316,015 $ 364,544 $ 361,017 Less: Interest expense (84,708 ) (110,717 ) (124,329 ) Interest expense - amortization of deferred financing costs (2,696 ) (4,557 ) (5,148 ) Interest expense - financing obligation (679 ) (1,237 ) (1,144 ) Depreciation and amortization (189,676 ) (219,029 ) (208,569 ) General and administrative expenses (26,596 ) (29,406 ) (26,779 ) Equity in loss of real estate ventures (11,503 ) (811 ) (790 ) Provision for impairment (40,517 ) (82,208 ) (1,765 ) Plus: Interest income 1,236 1,224 3,974 Tax credit transaction income - 19,955 11,853 Recognized hedge activity - - (828 ) Net gain from remeasurement of investments in real estate ventures - 758 458 Net gain on sales of interests in real estate 116,983 20,496 4,901 Net gain on sale of undepreciated real estate 9,232 3,019 1,184 Net gain (loss) on real estate venture transactions 20,000 7,229 (417 ) Loss on early extinguishment of debt (66,590 ) - (7,594 ) Income (loss) from continuing operations 40,501 (30,740 ) 6,024 Income from discontinued operations - - 918 Net income (loss) $ 40,501 $ (30,740 ) $ 6,942

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2016
Leases Operating [Abstract]
Operating Leases Future Minimum Payments Receivable	The Company leases properties to tenants under operating leases with various expiration dates extending to 2082. Minimum future rentals on non-cancelable leases at December 31, 2016 are as follows (in thousands): Year Minimum Rent 2017 $ 374,726 2018 370,439 2019 341,956 2020 311,075 2021 271,870 Thereafter 1,292,599

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2016
Commitments And Contingencies Disclosure [Abstract]
Minimum Future Rental Payments on Non-cancelable Leases	Minimum future rental payments on non-cancelable leases at December 31, 2016 are as follows (in thousands): Year Minimum Rent 2017 $ 1,339 2018 1,339 2019 1,339 2020 1,339 2021 1,339 Thereafter 66,231 Total $ 72,926

Summary of Quarterly Results (T

Summary of Quarterly Results (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Quarterly Financial Information	The following is a summary of quarterly financial information as of and for the years ended December 31, 2016 and 2015 (in thousands, except per share data): Brandywine Realty Trust 1st 2nd 3rd 4th Quarter Quarter Quarter Quarter 2016 Total revenue $ 136,502 $ 127,181 $ 129,694 $ 132,086 Net income (loss) 46,310 (1,323 ) 7,884 (12,370 ) Net income (loss) allocated to Common Shares 44,091 (3,105 ) 6,022 (14,058 ) Basic earnings (loss) per Common Share $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) Diluted earnings (loss) per Common Share $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) 2015 Total revenue $ 150,406 $ 145,648 $ 152,585 $ 153,992 Net income (loss) 8,594 3,058 20,308 (62,700 ) Net income (loss) allocated to Common Shares 6,710 1,255 18,346 (63,941 ) Basic earnings (loss) per Common Share $ 0.04 $ 0.01 $ 0.10 $ (0.37 ) Diluted earnings (loss) per Common Share $ 0.04 $ 0.01 $ 0.10 $ (0.37 )
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Quarterly Financial Information	Brandywine Operating Partnership, L.P. 1st 2nd 3rd 4th Quarter Quarter Quarter Quarter 2016 Total revenue $ 136,502 $ 127,181 $ 129,694 $ 132,086 Net income (loss) 46,310 (1,323 ) 7,884 (12,370 ) Net income (loss) attributable to Common Partnership Unitholders 44,478 (3,131 ) 6,074 (14,176 ) Basic earnings (loss) per Common Partnership Unit $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) Diluted earnings (loss) per Common Partnership Unit $ 0.25 $ (0.02 ) $ 0.03 $ (0.08 ) 2015 Total revenue $ 150,406 $ 145,648 $ 152,585 $ 153,992 Net income (loss) 8,594 3,058 20,308 (62,700 ) Net income (loss) attributable to Common Partnership Unitholders 6,768 1,262 18,506 (64,502 ) Basic earnings (loss) per Common Partnership Unit $ 0.04 $ 0.04 $ 0.10 $ (0.36 ) Diluted earnings (loss) per Common Partnership Unit $ 0.04 $ 0.04 $ 0.10 $ (0.36 )

Organization of The Parent Co55

Organization of The Parent Company and The Operating Partnership (Textual) (Details)	Dec. 31, 2016	Dec. 31, 2016property	Dec. 31, 2016ft²	Dec. 31, 2016Real_Estate_Investment	Dec. 31, 2016a	Dec. 31, 2016Apartment_unit	Feb. 04, 2016property	Dec. 31, 2015ft²	Dec. 31, 2014ft²
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		113
Office Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		93
Rentable Square Feet | ft²			5,239,632					2,649,926	645,273
Industrial Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		4					20
Mixed Use Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		7
Retail Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		1
Core Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		101
Development Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		4
Redevelopment Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		3
Assets Held-for-sale [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties		5
Unconsolidated Real Estate Ventures [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment				14
Unconsolidated Real Estate Ventures [Member] | Seven Real Estate Ventures [Member] | Office Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment				7
Rentable Square Feet | ft²			8,000,000
Unconsolidated Real Estate Ventures [Member] | Two Real Estate Ventures [Member] | Undeveloped Land [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment				2
Acreage of land | a					4.3
Unconsolidated Real Estate Ventures [Member] | Two Other Real Estate Ventures [Member] | Under Active Development Land [Member]
Organization of The Parent Company and The Operating Partnership [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] | Two Other Real Estate Ventures [Member] | Residential Tower One [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment				1
Number of Property units		345				345
Unconsolidated Real Estate Ventures [Member] | Two Other Real Estate Ventures [Member] | Residential Tower Two [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment				1
Number of Property units		321				321
Number of Unconsolidated Investments in Real Estate Ventures		1
Unconsolidated Real Estate Ventures [Member] | One Real Estate Venture [Member] | Apartment Complex [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment				1
Number of Property units		398				398
Parent Company [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the Operating Partnership	99.10%
Net Rentable Square Feet | ft²			17,600,000
Area Owned by Company of Undeveloped Parcels of Land | a					317
Undeveloped Land Held for Sale. | a					5
Area of Additional Undeveloped Parcels of Land With Option to Purchase | a					60
Total Potential Development Capacity | ft²			12,300,000
Wholly-owned Management Company Subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²			28,100,000
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 | ft²			10,500,000
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 | ft²			17,600,000
Wholly-owned Management Company Subsidiaries [Member] | Office and Industrial Properties [Member] | Partially Owned Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²			10,500,000
Subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the Operating Partnership	100.00%

Summary of Significant Accoun56

Summary of Significant Accounting Policies (Textual) (Details)	12 Months Ended
	Dec. 31, 2016USD ($)Customershares	Dec. 31, 2015USD ($)Customer	Dec. 31, 2014USD ($)Customer	Jan. 31, 2017USD ($)	Jun. 10, 2016USD ($)	Jun. 02, 2010shares
Summary Of Significant Accounting Policies (Textual) [Abstract]
Real estate ventures aggregate indebtedness to third parties	$ 997,466,000	$ 794,571,000
Revenue increased by straight-line rent adjustment	26,300,000	21,600,000	$ 13,700,000
Increased revenue due to amortization of deferred rent	2,100,000	2,000,000	2,400,000
Decrease in revenue due to amortization of lease incentives	2,000,000	1,800,000	1,500,000
Share-based compensation expense	5,600,000	7,300,000	6,100,000
Share-based compensation expense, capitalized	1,000,000	1,900,000	$ 1,700,000
Variable interest entity, assets	417,100,000	422,900,000
Variable interest entity, liabilities	$ 254,600,000	$ 258,200,000
Common shares available for future awards | shares	4,295,559
Increase in Common shares available for future awards | shares						6,000,000
Employee Stock Option And Share Appreciation Rights
Summary Of Significant Accounting Policies (Textual) [Abstract]
Common shares available for future awards | shares	2,377,778					3,600,000
Customer Concentration Risk [Member] | Rental Revenue [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Number of tenant accounted for 10% or more of the Company's rents | Customer	0	0	0
Maximum [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Property, Plant and Equipment, Useful Life	55 years
Tenant Improvements Useful Lives	16 years
Minimum [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Property, Plant and Equipment, Useful Life	5 years
Tenant Improvements Useful Lives	1 year
TB-BDN Plymouth Apartments [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Guarantees, maximum exposure amount	$ 3,200,000
Construction Loan	56,000,000
TB-BDN Plymouth Apartments [Member] | Subsequent Event [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Sale of ownership interest percentage				50.00%
Guarantee obligations cancelled				$ 3,200,000
1919 Venture [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Guarantees, maximum exposure amount	88,900,000
Unconsolidated Real Estate Ventures [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Real estate ventures aggregate indebtedness to third parties	997,466,000
Capitalized interest	1,900,000	$ 2,000,000	$ 2,000,000
evo at Cira Centre South Venture [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Guarantor obligations, current carrying value	52,500,000
Construction Loan					$ 97,800,000
PJP VII [Member]
Summary Of Significant Accounting Policies (Textual) [Abstract]
Real estate ventures aggregate indebtedness to third parties	4,956,000	$ 5,621,000
Guarantees, maximum exposure amount	$ 400,000

Summary of Significant Accoun57

Summary of Significant Accounting Policies - Construction-in-Progress (Textual) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Construction in Progress [Line Items]
Internal direct construction costs capitalized related to development of properties and land holdings	$ 6,717	$ 7,291	$ 5,194
Development [Member]
Construction in Progress [Line Items]
Internal direct construction costs capitalized related to development of properties and land holdings	3,182	2,641	1,749
Capitalized interest	$ 10,900	$ 10,200	$ 4,800

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Compensation Costs (Including Bonuses and Benefits) Capitalized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	$ 6,717	$ 7,291	$ 5,194
Development [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	3,182	2,641	1,749
Redevelopment [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	144	221	184
Tenant Improvements [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	$ 3,391	$ 4,429	$ 3,261

Summary of Significant Accoun59

Summary of Significant Accounting Policies - Impairment or Disposal of Long-Lived Assets (Textual) (Details)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Disposition of assets, holding period	10 years

Summary of Significant Accoun60

Summary of Significant Accounting Policies - Accounts Receivable and Accrued Rent Receivable (Textual) (Details) $ in Thousands	Dec. 31, 2016USD ($)Customer	Dec. 31, 2015USD ($)Customer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 2,373	$ 1,736
Tenant Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	2,400	1,700
Accrued Rent Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 13,700	$ 14,500
Accounts Receivable [Member] | Customer Concentration Risk [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of tenant accounted for 10% or more of the Company's accounts receivable | Customer	0	0

Summary of Significant Accoun61

Summary of Significant Accounting Policies - Deferred Costs (Textual) (Details)	12 Months Ended
	Dec. 31, 2016
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Remaining Lease Period - Minimum	1 year
Remaining Lease Period - Maximum	16 years

Summary of Significant Accoun62

Summary of Significant Accounting Policies - Notes Receivable (Textual) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan maturity term	3 years
Note receivable	$ 3.4
Note Receivable Year One [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan bears interest rate	6.30%
Note Receivable Year Two [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan bears interest rate	7.00%
Note Receivable Year Three [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan bears interest rate	8.00%

Summary of Significant Accoun63

Summary of Significant Accounting Policies - Income Taxes (Textual) (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Contingency [Line Items]
Distributable Income Minimum Percentage	90.00%
Tax Basis of Assets, Cost for Income Tax Purposes	$ 3	$ 3.9
Federal excise tax if sufficient taxable income is not distributed within prescribed time limits	4.00%
Excise tax equal to annual amount	4.00%
Excise tax, if sum of ordinary income	85.00%
Excise tax, if Net capital gain exceeds cash distributions and certain taxes paid	95.00%
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Income Tax Contingency [Line Items]
Tax Basis of Assets, Cost for Income Tax Purposes	$ 3	$ 3.9

Real Estate Investments - Gross

Real Estate Investments - Gross Carrying Value of Company's Properties (Details) - USD ($) $ in Thousands		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Property, Plant and Equipment, Gross [Abstract]
Land		$ 469,522		$ 513,268
Tenant improvements		433,686		459,952
Operating properties		3,586,295		3,693,000
Assets held for sale - real estate investments	[1],[2]	73,591	[3]	794,588	[3]	$ 27,436
Total		3,659,886		4,487,588
Building and Improvements [Member]
Property, Plant and Equipment, Gross [Abstract]
Operating properties		$ 2,683,087		$ 2,719,780
[1]	As of December 31, 2015, 2970 Market Street was classified as held for sale on the consolidated balance sheets. The property was sold on February 5, 2016. See Note 21, "Subsequent Events," for further information. The sale is not classified as a significant disposition under the accounting guidance for discontinued operations.
[2]	As of December 31, 2015, the 58 properties associated with the series of related transactions with Och-Ziff Real Estate were classified as held for sale on the consolidated balance sheets. On February 4, 2016, the Company completed a series of transactions, resulting in the disposition of the properties. See Note 3, “Real Estate Investments,” for further information regarding the disposition. Additionally, as of December 31, 2016, the Company categorized three office properties located in the Metropolitan Washington, D.C. segment and two properties in the Other segment as held for sale in accordance with applicable accounting standards for long lived assets. See Note 3, “Real Estate Investments,” for further information.
[3]	Real estate investments related to assets held for sale above represents gross real estate assets and does not include accumulated depreciation or other assets on the balance sheets of the properties held for sale. See Held for Sale section below.

Real Estate Investments - Acqui

Real Estate Investments - Acquisitions (Textual) (Details) $ in Thousands	Jul. 01, 2016USD ($)a	Jul. 07, 2015USD ($)a	Jun. 22, 2015USD ($)ft²aproperty	May 12, 2015USD ($)ft²	Apr. 06, 2015USD ($)a	Apr. 02, 2015USD ($)ft²	Feb. 19, 2014USD ($)ft²apropertyFloor	Dec. 31, 2016USD ($)a	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)ft²Storey	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)a	Dec. 31, 2015USD ($)ft²Storey	Dec. 31, 2014USD ($)	Jan. 30, 2017a	Jun. 30, 2014USD ($)
Business Acquisition [Line Items]
Amount funded by corporate funds																$ 20,406	$ 150,472	$ 18,443
Net gain from remeasurement of investments in real estate ventures																0	758	458
Revenue								$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	525,463	602,631	596,982
Net losses								(14,058)	$ 6,022	$ (3,105)	$ 44,091	(63,941)	$ 18,346	$ 1,255	$ 6,710	40,191	(30,401)	6,975
Development in Progress								$ 297,462				$ 268,983				$ 297,462	268,983	201,360
Encino Trace - Building I [Member]
Business Acquisition [Line Items]
Construction in Progress, Gross																		38,800
2100 Market Street [Member]
Business Acquisition [Line Items]
Acreage of land | a		0.8
Payments to Acquire Land		$ 18,800
Amount funded by corporate funds		16,800
Amount Deferred		$ 2,000
Settlement Period		24 months
25 M Street [Member]
Business Acquisition [Line Items]
Acreage of land | a					0.8
Payments to Acquire Land					$ 20,300
Acquisition Costs					$ 300
Area of Real Estate Property | ft²				271,000
25 M Street [Member] | Brandywine 25 M Street [Member]
Business Acquisition [Line Items]
Percent of Acquired Entity				95.00%
Subsequent Event [Member] | Garza Land Sale [Member]
Business Acquisition [Line Items]
Area of land under agreement to sell | a																			1.7
Garza Land Acquisition [Member]
Business Acquisition [Line Items]
Acreage of land | a	34.6
Gross purchase value of assets	$ 20,600
Acquisition costs	1,900
Amount funded by corporate funds	$ 20,400
Area of land under agreement to sell | a								9.5								9.5
Broadmoor Austin Associates [Member]
Business Acquisition [Line Items]
Acreage of land | a			66
Payments to Acquire Land			$ 143,800
Amount funded by corporate funds			$ 81,000
Percentage of ownership interests			50.00%
Number of Property units | property			7
Purchase Price of Assets			$ 211,400
Carrying amount of Investment			$ 66,300
Rentable Square Feet | ft²			1,112,236
Lease percentage of acquired property			100.00%
Funds Held in Escrow			$ 62,800
Mortgage Debt Paid at Closing			51,200
Acquisition Costs			$ 200															$ 200
Ownership percentage			50.00%
Net gain from remeasurement of investments in real estate ventures			$ 800
Revenue																$ 26,400	13,200
Net losses																$ 5,200	$ 7,200
Building, land and improvements			$ 163,271
25 M Street [Member] | 25 M Street [Member]
Business Acquisition [Line Items]
Payments to Acquire Land				$ 1,000
Asset Acquisition Ownership Percent				5.00%
618 Market Street [Member]
Business Acquisition [Line Items]
Payments to Acquire Land						$ 19,400
Area of Real Estate Property | ft²						14,404
Number of Parking Spaces | ft²						330
Fair Value of Contingent Consideration						$ 1,600
Consideration, Cash						17,800
Building, land and improvements						19,200
Intangible Assets						$ 200
Encino Trace - Land [Member]
Business Acquisition [Line Items]
Acreage of land | a							54.1
Payments to Acquire Land							$ 14,000
Rentable Square Feet | ft²							320,000					320,000					320,000
Lease percentage of acquired property							75.00%
Funds Held in Escrow							$ 1,000
Construction in Progress, Gross							8,400
Development in Progress							$ 4,600													$ 4,600
Number of potential development properties | property							2
Number of floors of a building							4					4					4

Real Estate Investments - Summa

Real Estate Investments - Summary of Office Properties Sold (Details)		Feb. 04, 2016property	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)ft²property		Dec. 31, 2015USD ($)ft²property		Dec. 31, 2014USD ($)ft²property		Dec. 23, 2015ft²
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties					$ 784,331,000		$ 247,228,000		$ 118,855,000
Gain (Loss) on Sale					$ 116,983,000		$ 20,496,000		$ 4,901,000
2970 Market Street (Cira Square) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²											862,692
Encino Trace [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							2
Rentable Square Feet | ft²							320,000
11305 Four Points Drive (Four Points Centre) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property									2
Rentable Square Feet | ft²									192,396
Office Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property					66		27		8
Rentable Square Feet | ft²					5,239,632		2,649,926		645,273
Sales Price					$ 820,000,000		$ 374,600,000		$ 101,150,000
Proceeds from the sale of properties					769,799,000		340,098,000		113,024,000
Gain (Loss) on Sale					$ 116,983,000	[1]	$ 22,002,000	[2],[3]	$ 4,646,000	[4]
Office Properties [Member] | 620, 640, 660 Allendale Road [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property					3
Rentable Square Feet | ft²					156,669
Sales Price					$ 12,800,000
Proceeds from the sale of properties					12,014,000
Gain (Loss) on Sale	[1]				$ 2,382,000
Office Properties [Member] | 1120 Executive Plaza [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property					1
Rentable Square Feet | ft²					95,183
Sales Price					$ 9,500,000
Proceeds from the sale of properties					9,241,000
Gain (Loss) on Sale	[1],[5]				$ (18,000)
Office Properties [Member] | 50 East Clementon Road [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property					1
Rentable Square Feet | ft²					3,080
Sales Price					$ 1,100,000
Proceeds from the sale of properties					1,011,000
Gain (Loss) on Sale	[1]				$ (85,000)
Office Properties [Member] | 196/198 Van Buren Street (Herndon Metro Plaza I&II) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property					2
Rentable Square Feet | ft²					197,225
Sales Price					$ 44,500,000
Proceeds from the sale of properties					43,412,000
Gain (Loss) on Sale	[1],[6]				$ (752,000)
Office Properties [Member] | 2970 Market Street (Cira Square) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property					1
Rentable Square Feet | ft²					862,692
Sales Price					$ 354,000,000
Proceeds from the sale of properties					350,150,000
Gain (Loss) on Sale	[1]				$ 115,828,000
Office Properties [Member] | Och Ziff Portfolio [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property		58			58	[7]
Rentable Square Feet | ft²	[7]				3,924,783
Sales Price	[7]				$ 398,100,000
Proceeds from the sale of properties	[7]				353,971,000
Gain (Loss) on Sale	[1],[7],[8]				$ (372,000)
Office Properties [Member] | Encino Trace [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							2
Rentable Square Feet | ft²							320,000
Sales Price							$ 76,700,000
Proceeds from the sale of properties							50,158,000
Gain (Loss) on Sale	[2],[9]						$ 2,008,000
Office Properties [Member] | Laurel Corporate Center [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							6
Rentable Square Feet | ft²							560,147
Sales Price							$ 56,500,000
Proceeds from the sale of properties							56,253,000
Gain (Loss) on Sale	[2]						$ 2,901,000
Office Properties [Member] | Carlsbad Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							3
Rentable Square Feet | ft²							196,075
Sales Price							$ 30,400,000
Proceeds from the sale of properties							29,568,000
Gain (Loss) on Sale	[2],[10]						$ 0
Office Properties [Member] | 751-761 Fifth Ave [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							1
Rentable Square Feet | ft²							158,000
Sales Price							$ 4,600,000
Proceeds from the sale of properties							4,245,000
Gain (Loss) on Sale	[2]						$ 894,000
Office Properties [Member] | 1000 Howard Boulevard [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							1
Rentable Square Feet | ft²							105,312
Sales Price							$ 16,500,000
Proceeds from the sale of properties							15,780,000
Gain (Loss) on Sale	[2]						$ 4,828,000
Office Properties [Member] | Bay Colony Office Park [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							4
Rentable Square Feet | ft²							247,294
Sales Price							$ 37,500,000
Proceeds from the sale of properties							36,386,000
Gain (Loss) on Sale	[2]						$ 269,000
Office Properties [Member] | 741 First Avenue [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							1
Rentable Square Feet | ft²							77,184
Sales Price							$ 4,900,000
Proceeds from the sale of properties							4,640,000
Gain (Loss) on Sale	[2]						$ 372,000
Office Properties [Member] | 100 Gateway Centre Parkway [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							1
Rentable Square Feet | ft²							74,991
Sales Price							$ 4,100,000
Proceeds from the sale of properties							3,911,000
Gain (Loss) on Sale			$ 0				$ 0	[2],[11]
Office Properties [Member] | Christina & Delaware Corporate Centers [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							5
Rentable Square Feet | ft²							485,182
Sales Price							$ 50,100,000
Proceeds from the sale of properties							49,579,000
Gain (Loss) on Sale	[2]						$ 1,749,000
Office Properties [Member] | Lake Merritt Tower [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							1
Rentable Square Feet | ft²							204,336
Sales Price							$ 65,000,000
Proceeds from the sale of properties							62,800,000
Gain (Loss) on Sale				$ 0			$ 0	[2],[12]
Office Properties [Member] | 1000 Atrium Way / 457 Haddonfield Road (Atrium I / Libertyview) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property							2
Rentable Square Feet | ft²							221,405
Sales Price							$ 28,300,000
Proceeds from the sale of properties							26,778,000
Gain (Loss) on Sale	[2]						$ 8,981,000
Office Properties [Member] | 100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Properties) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property									5
Rentable Square Feet | ft²									279,934
Sales Price									$ 37,900,000
Proceeds from the sale of properties									37,156,000
Gain (Loss) on Sale	[4],[13]								$ 203,000
Office Properties [Member] | 1880 Campus Commons Drive (Campus Pointe) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property									1
Rentable Square Feet | ft²									172,943
Sales Price									$ 42,500,000
Proceeds from the sale of properties									41,476,000
Gain (Loss) on Sale	[4]								$ 4,698,000
Office Properties [Member] | 11305 Four Points Drive (Four Points Centre) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property									2
Rentable Square Feet | ft²									192,396
Sales Price									$ 20,750,000
Proceeds from the sale of properties									34,392,000
Gain (Loss) on Sale	[4],[14]								$ (255,000)
[1]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[2]	Gain on Sale is net of closing and other transaction related costs.
[3]	Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale.
[4]	Gain/(Loss) on sale is net of closing and other transaction related costs.
[5]	As of June 30, 2016, the Company determined that the sale of the property was probable and classified this property as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the property exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized a provision for impairment totaling approximately $1.8 million during the three-month period ended June 30, 2016. The fair value measurement was based on the pricing in the purchase and sale agreement for the sale of the property. As the pricing in the purchase and sale agreement is unobservable, the Company determined that the inputs utilized to determine fair value for this property falls within Level 3 in accordance with the fair value hierarchy established by Accounting Standards Codification (ASC) Topic 820, "Fair Value Measurements and Disclosures.” The loss on sale represents additional closing costs recognized at closing.
[6]	During the three-month period ended March 31, 2016, the Company recognized a provision for impairment totaling approximately $7.4 million on the properties. See “Held for Use Impairment” section below. The loss on sale primarily relates to additional closing costs recognized at closing.
[7]	Exhibit 99.2 to the Company’s Current Report on Form 8-K filed on February 10, 2016 contains a complete list of the 58 properties disposed of in the transactions with Och-Ziff Capital Management Group LLC. See Note 4, "Investment in Unconsolidated Real Estate Ventures," for further details of the transactions.
[8]	During the three-month period ended December 31, 2015, the Company recognized a provision for impairment totaling approximately $45.4 million. The loss on sale represents additional closing costs recognized at closing.
[9]	On December 31, 2015, the Company contributed two newly constructed four-story, Class A office buildings, commonly known as “Encino Trace,” containing an aggregate of approximately 320,000 square feet in Austin, Texas to one of its existing real estate ventures (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). When these two properties were contributed to the Austin Venture the Company had incurred a total of $76.7 million of development costs, representing the contribution value. The project is expected to cost $91.3 million with remaining costs fully funded by the Austin Venture. In conjunction with the contribution: (i) the Austin Venture obtained a $30.0 million mortgage loan; (ii) DRA contributed $25.1 million in net cash to the capital of the Austin Venture, including a $1.8 million working capital contribution; and (iii) the Austin Venture distributed $50.2 million to the Company and credited the Company with a $23.3 million capital contribution to the Austin Venture. In addition to the contribution of the properties, the Company also made a $1.8 million cash contribution to the Austin Venture for working capital. The Company recognized a $2.0 million gain on the contribution. Under the Encino Trace loan agreement the Austin Venture has the option, subject to certain leasing and loan-to-value requirements, to borrow an additional $29.7 million to fund tenant improvements and leasing commissions.
[10]	The Company recorded an impairment loss of $6.3 million for the Carlsbad office properties during the fourth quarter of 2015. As such, there was no gain at disposition for this property.
[11]	The Company recorded an impairment loss of $0.8 million for 100 Gateway Centre Parkway during the second quarter of 2015. As such, there was no gain at disposition for this property.
[12]	The Company recorded an impairment loss of $1.7 million for Lake Merritt Tower at March 31, 2015. As such, there was no gain at disposition for this property. Sales proceeds were deposited in escrow under Section 1031 of the Internal Revenue Code and applied to purchase the Broadmoor Austin portfolio. Refer to Broadmoor Austin Associates acquisition summary, above, for further details.
[13]	During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties.
[14]	On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of approximately 192,396 net rentable square feet in Austin, Texas to an existing real estate venture (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). The Company contributed the properties to the Austin Venture at an agreed upon value of $41.5 million. In conjunction with the contribution: (i) the Austin Venture obtained a $29.0 million mortgage loan; (ii) DRA contributed $5.9 million in net cash to the capital of the Austin Venture; and (iii) the Austin Venture distributed $34.4 million to the Company and credited the Company with a $5.9 million capital contribution to the Austin Venture. The Company incurred a $0.2 million loss on the contribution, driven primarily by closing costs.

Real Estate Investments - Sum67

Real Estate Investments - Summary of Office Properties Sold (Parenthetical) (Details)

Feb. 04, 2016property

Jun. 30, 2016USD ($)

Mar. 31, 2016USD ($)

Dec. 31, 2015USD ($)ft²Storey

Jun. 30, 2015USD ($)

Mar. 31, 2015USD ($)

Sep. 30, 2014USD ($)

Dec. 31, 2016USD ($)ft²property

Dec. 31, 2015USD ($)ft²propertyStorey

Dec. 31, 2014USD ($)ft²propertyStorey

Oct. 17, 2014ft²

Jul. 31, 2014ft²

Apr. 03, 2014USD ($)ft²Storey

Oct. 16, 2013USD ($)

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Provision for impairment

$ 1,800,000

$ 40,517,000

$ 82,208,000

$ 1,765,000

Impairment of properties held for use

7,300,000

Gain (loss) on real estate venture transactions

20,000,000

7,229,000

(417,000)

Gain (Loss) on Sale

$ 116,983,000

$ 20,496,000

$ 4,901,000

Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Rentable Square Feet | ft²

590,881

232,274

Brandywine Realty Trust [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Aggregate gross sales price of a joint venture

$ 330,000,000

Encino Trace [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

2

Number of floors of a building | Storey

4

4

Rentable Square Feet | ft²

320,000

320,000

Encino Trace [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Project expected cost

$ 91,300,000

Non-Recourse Debt

$ 30,000,000

30,000,000

Amount Of Participant Contribution

1,800,000

1,800,000

Encino Trace [Member] | Brandywine Realty Trust [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Development costs

76,700,000

76,700,000

Proceeds from Equity Method Investment, Dividends or Distributions

50,200,000

Capital contribution

23,300,000

23,300,000

Gain (loss) on real estate venture transactions

2,000,000

Additional borrowing fund to tenant improvements and leasing commissions

29,700,000

29,700,000

Encino Trace [Member] | DRA Advisors LLC [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Working capital contribution

1,800,000

1,800,000

Encino Trace [Member] | DRA Advisors LLC [Member] | Brandywine Realty Trust [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Amount Of Participant Contribution

$ 25,100,000

$ 25,100,000

100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Properties) [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Provision for impairment on assets held for sale

$ 1,800,000

11305 Four Points Drive (Four Points Centre) [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

2

Number of floors of a building | Storey

3

3

Rentable Square Feet | ft²

192,396

11305 Four Points Drive (Four Points Centre) [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Non-Recourse Debt

$ 29,000,000

11305 Four Points Drive (Four Points Centre) [Member] | Brandywine Realty Trust [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Amount Of Participant Contribution

5,900,000

Gain (loss) on real estate venture transactions

$ (200,000)

Additional borrowing fund to tenant improvements and leasing commissions

$ 34,400,000

Aggregate gross sales price of a joint venture

$ 41,500,000

Office Properties [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

66

27

8

Rentable Square Feet | ft²

2,649,926

5,239,632

2,649,926

645,273

Gain (Loss) on Sale

$ 116,983,000

[1]

$ 22,002,000

[2],[3]

$ 4,646,000

[4]

Deferred gain

$ 500,000

$ 500,000

Office Properties [Member] | 196/198 Van Buren Street (Herndon Metro Plaza I&II) [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Impairment of properties held for use

$ 7,400,000

Number of Properties Sold | property

2

Rentable Square Feet | ft²

197,225

Gain (Loss) on Sale

[1],[5]

$ (752,000)

Office Properties [Member] | Och Ziff Portfolio [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

58

58

[6]

Provision for impairment on assets held for sale

$ 45,400,000

Rentable Square Feet | ft²

[6]

3,924,783

Gain (Loss) on Sale

[1],[6],[7]

$ (372,000)

Office Properties [Member] | Encino Trace [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

2

Rentable Square Feet | ft²

320,000

320,000

Gain (Loss) on Sale

[2],[8]

$ 2,008,000

Office Properties [Member] | Carlsbad, CA [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Provision for impairment on assets held for sale

$ 6,300,000

Gain (Loss) on Sale

$ 0

Office Properties [Member] | 100 Gateway Centre Parkway [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

1

Provision for impairment on assets held for sale

$ 800,000

Rentable Square Feet | ft²

74,991

74,991

Gain (Loss) on Sale

$ 0

$ 0

[2],[9]

Office Properties [Member] | Lake Merritt Tower [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

1

Provision for impairment on assets held for sale

$ 1,700,000

Rentable Square Feet | ft²

204,336

204,336

Gain (Loss) on Sale

$ 0

$ 0

[2],[10]

Office Properties [Member] | 100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Properties) [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

5

Rentable Square Feet | ft²

279,934

Gain (Loss) on Sale

[4],[11]

$ 203,000

Office Properties [Member] | 11305 Four Points Drive (Four Points Centre) [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Number of Properties Sold | property

2

Rentable Square Feet | ft²

192,396

Gain (Loss) on Sale

[4],[12]

$ (255,000)

Office Properties [Member] | 11305 Four Points Drive (Four Points Centre) [Member] | Austin Joint Venture [Member]

Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]

Rentable Square Feet | ft²

192,396

[1]

Gain/(Loss) on Sale is net of closing and other transaction related costs.

[2]

Gain on Sale is net of closing and other transaction related costs.

[3]

Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale.

[4]

Gain/(Loss) on sale is net of closing and other transaction related costs.

[5]

During the three-month period ended March 31, 2016, the Company recognized a provision for impairment totaling approximately $7.4 million on the properties. See “Held for Use Impairment” section below. The loss on sale primarily relates to additional closing costs recognized at closing.

[6]

Exhibit 99.2 to the Company’s Current Report on Form 8-K filed on February 10, 2016 contains a complete list of the 58 properties disposed of in the transactions with Och-Ziff Capital Management Group LLC. See Note 4, "Investment in Unconsolidated Real Estate Ventures," for further details of the transactions.

[7]

During the three-month period ended December 31, 2015, the Company recognized a provision for impairment totaling approximately $45.4 million. The loss on sale represents additional closing costs recognized at closing.

[8]

On December 31, 2015, the Company contributed two newly constructed four-story, Class A office buildings, commonly known as “Encino Trace,” containing an aggregate of approximately 320,000 square feet in Austin, Texas to one of its existing real estate ventures (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). When these two properties were contributed to the Austin Venture the Company had incurred a total of $76.7 million of development costs, representing the contribution value. The project is expected to cost $91.3 million with remaining costs fully funded by the Austin Venture. In conjunction with the contribution: (i) the Austin Venture obtained a $30.0 million mortgage loan; (ii) DRA contributed $25.1 million in net cash to the capital of the Austin Venture, including a $1.8 million working capital contribution; and (iii) the Austin Venture distributed $50.2 million to the Company and credited the Company with a $23.3 million capital contribution to the Austin Venture. In addition to the contribution of the properties, the Company also made a $1.8 million cash contribution to the Austin Venture for working capital. The Company recognized a $2.0 million gain on the contribution. Under the Encino Trace loan agreement the Austin Venture has the option, subject to certain leasing and loan-to-value requirements, to borrow an additional $29.7 million to fund tenant improvements and leasing commissions.

[9]

The Company recorded an impairment loss of $0.8 million for 100 Gateway Centre Parkway during the second quarter of 2015. As such, there was no gain at disposition for this property.

[10]

The Company recorded an impairment loss of $1.7 million for Lake Merritt Tower at March 31, 2015. As such, there was no gain at disposition for this property. Sales proceeds were deposited in escrow under Section 1031 of the Internal Revenue Code and applied to purchase the Broadmoor Austin portfolio. Refer to Broadmoor Austin Associates acquisition summary, above, for further details.

[11]

During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties.

[12]

On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of approximately 192,396 net rentable square feet in Austin, Texas to an existing real estate venture (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). The Company contributed the properties to the Austin Venture at an agreed upon value of $41.5 million. In conjunction with the contribution: (i) the Austin Venture obtained a $29.0 million mortgage loan; (ii) DRA contributed $5.9 million in net cash to the capital of the Austin Venture; and (iii) the Austin Venture distributed $34.4 million to the Company and credited the Company with a $5.9 million capital contribution to the Austin Venture. The Company incurred a $0.2 million loss on the contribution, driven primarily by closing costs.

Real Estate Investments - Sum68

Real Estate Investments - Summary of Land Parcels Sold (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2016USD ($)aParcel		Dec. 31, 2015USD ($)aParcel		Dec. 31, 2014USD ($)aParcel		Jan. 15, 2016Parcel
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Proceeds from the sale of properties		$ 784,331		$ 247,228		$ 118,855
Gain (Loss) on Sale		$ 116,983		$ 20,496		$ 4,901
Greenhills Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel								120
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		3		4		2
Acreage of land | a		122.9		14.7		22.1
Sales Price		$ 14,938		$ 22,300		$ 5,120
Proceeds from the sale of properties		14,532		21,088		4,855
Gain (Loss) on Sale		$ 9,232	[1]	$ 3,019	[2]	$ 1,184	[3]
Land [Member] | Oakland Lot B [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		0.9
Sales Price		$ 13,750
Proceeds from the sale of properties		13,411
Gain (Loss) on Sale	[1]	$ 9,039
Land [Member] | Highlands 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		2
Sales Price		$ 288
Proceeds from the sale of properties		284
Gain (Loss) on Sale	[1]	$ 193
Land [Member] | Greenhills 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		120
Sales Price		$ 900
Proceeds from the sale of properties		837
Gain (Loss) on Sale	[1],[4]	$ 0
Land [Member] | Two Christina Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				1
Acreage of land | a				1.6
Sales Price				$ 6,500
Proceeds from the sale of properties				5,986
Gain (Loss) on Sale	[2],[5]			$ 0
Land [Member] | A7000 Midlantic [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				3.5
Sales Price				$ 2,200
Proceeds from the sale of properties				1,742
Gain (Loss) on Sale	[2]			$ (169)
Land [Member] | 11305 Four Points Drive (Four Points Centre) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				1
Acreage of land | a				8.6
Sales Price				$ 2,500
Proceeds from the sale of properties				2,344
Gain (Loss) on Sale	[2]			$ 71
Land [Member] | Two Kaiser Plaza [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				1
Acreage of land | a				1
Sales Price				$ 11,100
Proceeds from the sale of properties				11,016
Gain (Loss) on Sale	[2]			$ 3,117
Land [Member] | West Point II 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						5.3
Sales Price						$ 1,600
Proceeds from the sale of properties						1,505
Gain (Loss) on Sale	[3]					$ 12
Land [Member] | Rob Roy - 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						16.8
Sales Price						$ 3,520
Proceeds from the sale of properties						3,350
Gain (Loss) on Sale	[3]					$ 1,172
[1]	Gain on Sale is net of closing and other transaction related costs.
[2]	Gain/(Loss) on sale includes closing and other transaction related costs.
[3]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[4]	The carrying value of the land exceeded the fair value less the anticipated costs of sale as of December 31, 2015, therefore the Company recognized an impairment loss of $0.3 million during the three-month period ended December 31, 2015. There was no gain or loss recognized on the sale during 2016.
[5]	The Company recorded an impairment loss of $0.3 million for Two Christina Centre during the fourth quarter of 2015. As such, there was no gain/(loss) at disposition for this land parcel.

Real Estate Investments - Sum69

Real Estate Investments - Summary of Land Parcels Sold (Parenthetical) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Dec. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale			$ 116,983		$ 20,496		$ 4,901
Greenhills Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Provision for impairment on assets held for sale					300
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale			9,232	[1]	3,019	[2]	$ 1,184	[3]
Land [Member] | Greenhills Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale	[1],[4]		$ 0
Provision for impairment on assets held for sale		$ 300
Land [Member] | Two Christina Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale	[2],[5]				$ 0
Provision for impairment on assets held for sale		$ 300
[1]	Gain on Sale is net of closing and other transaction related costs.
[2]	Gain/(Loss) on sale includes closing and other transaction related costs.
[3]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[4]	The carrying value of the land exceeded the fair value less the anticipated costs of sale as of December 31, 2015, therefore the Company recognized an impairment loss of $0.3 million during the three-month period ended December 31, 2015. There was no gain or loss recognized on the sale during 2016.
[5]	The Company recorded an impairment loss of $0.3 million for Two Christina Centre during the fourth quarter of 2015. As such, there was no gain/(loss) at disposition for this land parcel.

Real Estate Investments - Dispo

Real Estate Investments - Dispositions (Textual) (Details)	3 Months Ended		12 Months Ended
	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)property	Dec. 31, 2016USD ($)apropertyParcel	Dec. 31, 2015USD ($)apropertyParcel	Dec. 31, 2014USD ($)ft²apropertyParcel
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property			113
Impairment of properties held for use			$ 7,300,000
Aggregate carrying value			25,800,000
Estimated Fair Value Of Impaired Property			$ 18,500,000
1000 Atrium Way [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²					99,668
Libertyview [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²					121,737
A 100 Atrium Way and Liberty View [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property					2
Provision for impairment on assets held for sale					$ 0
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel			3	4	2
Acreage of land | a			122.9	14.7	22.1
Other Segment [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property			3
Impairment of properties held for use			$ 7,300,000
Carrying value of real estate prior to impairment			25,800,000
Aggregate carrying value			$ 18,500,000
Impairment Hold Period			10 years
Residual Capitalization Rates			8.75%
Discount Rates			9.00%
Other Segment [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Impairment of properties held for use			$ 5,600,000
Carrying value of real estate prior to impairment			18,200,000
Aggregate carrying value			$ 12,600,000
Number of Parcels | Parcel			5
Acreage of land | a			108
Metropolitan DC [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property		2		3
Impairment of properties held for use	$ 3,900,000	$ 7,400,000		$ 27,500,000
Carrying value of real estate prior to impairment	37,400,000	51,900,000
Aggregate carrying value	$ 33,500,000	$ 44,500,000		$ 40,400,000
Impairment Hold Period	10 years	10 years		10 years
Residual Capitalization Rates	7.75%	7.00%		8.00%
Discount Rates	8.25%	7.00%		8.00%
Estimated Fair Value Of Impaired Property				$ 12,900,000

Real Estate Investments - Sum71

Real Estate Investments - Summary of Properties Classified as Held for Sale Included in Continuing Operations (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
ASSETS HELD FOR SALE
Total assets held for sale, net		$ 41,718	$ 584,365
LIABILITIES HELD FOR SALE
Total liabilities held for sale		81	2,151
Held for Sale Properties Included in Continuing Operations [Member]
ASSETS HELD FOR SALE
Operating properties		73,591	794,588
Accumulated depreciation		(32,916)	(213,581)
Operating real estate investments, net		40,675	581,007
Construction-in-progress			1,940
Land held for development		1,043	837
Total real estate investments, net		41,718	583,784
Intangible assets			581
Total assets held for sale, net		41,718	584,365
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net			192
Other liabilities		81	1,959
Total liabilities held for sale		81	2,151
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan D.C. - Office [Member]
ASSETS HELD FOR SALE
Operating properties	[1]	21,720
Accumulated depreciation	[1]	(11,935)
Operating real estate investments, net	[1]	9,785
Land held for development	[1]	0
Total real estate investments, net	[1]	9,785
Total assets held for sale, net	[1]	9,785
LIABILITIES HELD FOR SALE
Other liabilities	[1]	73
Total liabilities held for sale	[1]	73
Held for Sale Properties Included in Continuing Operations [Member] | Other Segment - Office [Member]
ASSETS HELD FOR SALE
Operating properties	[2]	51,871
Accumulated depreciation	[2]	(20,981)
Operating real estate investments, net	[2]	30,890
Land held for development	[2]	0
Total real estate investments, net	[2]	30,890
Total assets held for sale, net	[2]	30,890
LIABILITIES HELD FOR SALE
Other liabilities	[2]	8
Total liabilities held for sale	[2]	8
Held for Sale Properties Included in Continuing Operations [Member] | Other Segment - Land [Member]
ASSETS HELD FOR SALE
Operating properties	[3]	0
Accumulated depreciation	[3]	0
Operating real estate investments, net	[3]	0
Land held for development	[3]	1,043
Total real estate investments, net	[3]	1,043
Total assets held for sale, net	[3]	1,043
LIABILITIES HELD FOR SALE
Other liabilities	[3]	0
Total liabilities held for sale	[3]	$ 0
Held for Sale Properties Included in Continuing Operations [Member] | Och Ziff Properties [Member]
ASSETS HELD FOR SALE
Operating properties	[4]		526,099
Accumulated depreciation	[4]		(179,092)
Operating real estate investments, net	[4]		347,007
Construction-in-progress	[4]		1,915
Land held for development	[4]		0
Total real estate investments, net	[4]		348,922
Intangible assets	[4]		581
Total assets held for sale, net	[4]		349,503
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net	[4]		192
Other liabilities	[4]		1,959
Total liabilities held for sale	[4]		2,151
Held for Sale Properties Included in Continuing Operations [Member] | 2970 Market Street (Cira Square) [Member]
ASSETS HELD FOR SALE
Operating properties	[5]		268,489
Accumulated depreciation	[5]		(34,489)
Operating real estate investments, net	[5]		234,000
Construction-in-progress	[5]		25
Land held for development	[5]		0
Total real estate investments, net	[5]		234,025
Intangible assets	[5]		0
Total assets held for sale, net	[5]		234,025
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net	[5]		0
Other liabilities	[5]		0
Total liabilities held for sale	[5]		0
Held for Sale Properties Included in Continuing Operations [Member] | Greenhills Land [Member]
ASSETS HELD FOR SALE
Operating properties	[6]		0
Accumulated depreciation	[6]		0
Operating real estate investments, net	[6]		0
Construction-in-progress	[6]		0
Land held for development	[6]		837
Total real estate investments, net	[6]		837
Intangible assets	[6]		0
Total assets held for sale, net	[6]		837
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net	[6]		0
Other liabilities	[6]		0
Total liabilities held for sale	[6]		$ 0
[1]	As of December 31, 2016, the Company determined that the sale of three office properties in the Metropolitan D.C. segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded their fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $3.0 million during the three-month period ended December 31, 2016. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 9.00% and 10.00%, respectively. The results were comparable to indicative pricing in the market. As significant inputs to the model are unobservable, the Company determined that the value determined for this property falls within Level 3 fair value reporting.
[2]	As of December 31, 2016, the Company determined that the sale of two office properties in the Other segment was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $11.5 million during the three-month period ended December 31, 2016. The Company measured this impairment based on a discounted cash flow analysis, using a hold period of 10 years and residual capitalization rates and discount rates of 9.75% and 9.75%, respectively. The results were comparable to indicative pricing in the market. As significant inputs to the model are unobservable, the Company determined that the value determined for this property falls within Level 3 fair value reporting.
[3]	As of December 31, 2016, the Company determined that the sale of a land parcel in the Other segment was probable and classified the land parcel as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the land approximated the fair value less the anticipated costs of sale and the Company recorded a nominal impairment. The fair value measurement was based on the pricing in the purchase and sale.
[4]	On February 4, 2016, the Company disposed of its interests in 58 properties located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia segments in a series of related transactions with Och Ziff Real Estate. During the fourth quarter of 2015, significant provisions were agreed upon by both the Company and Och Ziff Real Estate and, as a result, the Company determined that the sale of the portfolio was probable and classified these properties as held for sale in accordance with applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $45.4 million during the year ended December 31, 2015. The fair value measurement was based on the pricing in the purchase and sale agreement. As the significant inputs to the model are unobservable, the Company determined that the value determined for these real estate investments fall within Level 3 for fair value reporting.
[5]	On December 23, 2015 the Company entered into a purchase and sale agreement to dispose of its equity interests in the office property located at 2970 Market Street in Philadelphia commonly known as 30th Street Main Post Office (“Cira Square”), which includes 862,692 square feet of rentable space and is fully leased to a single tenant. As of December 31, 2015, the Company determined the sale was probable and classified the property as held for sale in accordance with applicable accounting standards for long lived assets. As the fair value less anticipated costs to sell exceeded the carrying value of the property no impairment loss was recorded. The fair value measurement was based on the pricing in the purchase and sale agreement. As the sales price is unobservable, the Company determined that the significant inputs used to value this real estate investment falls within Level 3 for fair value reporting. On February 5, 2016 the Company completed the disposition of its equity interests in Cira Square.
[6]	On January 15, 2016, the Company sold the fee interest in a 120 acre land parcel located in Berks County, Pennsylvania for $0.9 million. As of December 31, 2015, the Company classified this land parcel as held for sale in accordance with the applicable accounting standards for long lived assets. At such date, the carrying value of the properties exceeded the fair value less the anticipated costs of sale. As a result, the Company recognized an impairment loss totaling approximately $0.3 million during the year ended December 31, 2015.

Real Estate Investments - Sum72

Real Estate Investments - Summary of Properties Classified as Held for Sale Included in Continuing Operations (Parenthetical) (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2016property	Dec. 31, 2015USD ($)	Feb. 04, 2016property	Jan. 15, 2016USD ($)Parcel	Dec. 23, 2015ft²
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Real Estate Properties | property				58
Och Ziff Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Provision for impairment on assets held for sale			$ 45,400,000
2970 Market Street (Cira Square) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Provision for impairment on assets held for sale			$ 0
Purchase and Sale Agreement Date			Dec. 23, 2015
Rentable Square Feet | ft²						862,692
Greenhills Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Provision for impairment on assets held for sale			$ 300,000
Number of Parcels | Parcel					120
Contractual Sales Price					$ 900,000
Held for Sale Properties Included in Continuing Operations [Member] | Metropolitan D.C. - Office [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property		3
Provision for impairment on assets held for sale	$ 3,000,000
Impairment Hold Period		10 years
Residual Capitalization Rates		9.00%
Discount Rates		10.00%
Held for Sale Properties Included in Continuing Operations [Member] | Other Segment - Office [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties Sold | property		2
Provision for impairment on assets held for sale	$ 11,500,000
Impairment Hold Period		10 years
Residual Capitalization Rates		9.75%
Discount Rates		9.75%

Real Estate Investments - Purch

Real Estate Investments - Purchase Price Allocation (Details) - Broadmoor Austin Associates [Member] $ in Thousands	Jun. 22, 2015USD ($)
Business Acquisition [Line Items]
Building, land and improvements	$ 163,271
Land inventory	6,045
Intangible assets acquired	50,637	[1]
Below market lease liabilities assumed	(8,600)	[2]
Total purchase price	211,353
Return of existing equity method investment	(66,324)
Gain on remeasurement	(758)
Net working capital assumed	(450)
Total cash payment at settlement	$ 143,821
[1]	Weighted average amortization period of 4.0 years.
[2]	Weighted average amortization period of 1.5 years

Real Estate Investments - Pur74

Real Estate Investments - Purchase Price Allocation (Parenthetical) (Details) - Broadmoor Austin Associates [Member]	Jun. 22, 2015
Intangible Assets Acquired [Member]
Business Acquisition [Line Items]
Weighted average amortization period	4 years
Below Market Lease [Member]
Business Acquisition [Line Items]
Weighted average amortization period	1 year 6 months

Real Estate Investments - Pro F

Real Estate Investments - Pro Forma (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings (loss) per common share from continuing operations:
Basic -- as reported									$ 0.19	$ (0.21)	$ (0.01)
Diluted -- as reported									0.19	(0.21)	(0.01)
Earnings (loss) per common share:
Basic -- as reported	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	0.19	(0.21)	0
Diluted -- as reported	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ 0.19	$ (0.21)	$ 0
Broadmoor Austin Associates [Member]
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Pro forma revenue										$ 612,649	$ 618,119
Pro forma income (loss) from continuing operations										(36,704)	(7,371)
Pro forma net income (loss) available to common shareholders										$ (43,594)	$ (13,669)
Earnings (loss) per common share from continuing operations:
Basic -- as reported										$ (0.17)	$ 0.04
Basic -- as pro forma										(0.21)	(0.04)
Diluted -- as reported										(0.17)	0.04
Diluted -- as pro forma										(0.21)	(0.04)
Earnings (loss) per common share:
Basic -- as reported										(0.21)
Basic -- as pro forma										(0.24)	(0.08)
Diluted -- as reported										(0.21)
Diluted -- as pro forma										$ (0.24)	$ (0.08)

Investment in Unconsolidated 76

Investment in Unconsolidated Real Estate Ventures (Textual) (Details)		Sep. 22, 2016USD ($)ft²	Aug. 31, 2016USD ($)	Aug. 19, 2016USD ($)	Jun. 30, 2016USD ($)ft²	Jun. 10, 2016USD ($)	Mar. 02, 2016USD ($)	Feb. 04, 2016USD ($)ft²property	Jan. 29, 2016USD ($)	Dec. 30, 2015USD ($)	Jun. 22, 2015USD ($)ft²apropertyBuilding	May 29, 2015USD ($)a	Jan. 30, 2015USD ($)	Oct. 21, 2014USD ($)	Oct. 17, 2014USD ($)ft²property	Oct. 15, 2014USD ($)	Jul. 31, 2014USD ($)ft²propertyStorey	Feb. 19, 2014USD ($)ft²aFloor	Oct. 16, 2013USD ($)ft²property	Jul. 31, 2013USD ($)ft²aproperty	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)		Jun. 30, 2016USD ($)ft²	Sep. 30, 2016USD ($)	Dec. 31, 2016USD ($)property		Dec. 31, 2015USD ($)ft²propertyStorey		Dec. 31, 2014USD ($)ft²propertyStorey		Dec. 31, 2013USD ($)	Dec. 31, 2011USD ($)	Jan. 31, 2017USD ($)	Dec. 31, 2016		Dec. 31, 2016property	Dec. 31, 2016ft²	Dec. 31, 2016Real_Estate_Investment	Dec. 31, 2016a	Dec. 31, 2016Apartment_unit	Apr. 03, 2014USD ($)ft²propertyStorey	Jan. 25, 2013USD ($)aStoreyBed	Jul. 10, 2012USD ($)ft²property	Dec. 20, 2011property	Jan. 20, 2011a	Dec. 19, 2007ft²property
Schedule Of Equity Method Investments [Line Items]
Equity Method Investments including net liabilities																												$ 239,874,000
Management fees																										$ 26,674,000		18,764,000		$ 17,200,000
Accounts receivable																						$ 12,446,000				12,446,000		17,126,000
Deconsolidated mortgage loan																										20,582,000		0		0
Deconsolidated financing liability																										12,384,000		0		0
Investment in Real Estate Ventures, equity method																						281,331,000				281,331,000		241,004,000		225,004,000
Capital funded to venture for mortgage debt																										28,610,000		68,549,000		46,098,000
Repayment of mortgage debt																										357,151,000		222,836,000		13,441,000
Provision for impairment of investment in real estate ventures																										7,300,000
Number of Properties | property																																					113
Proceeds from sale of real estate venture																										21,022,000		6,100,000		0
Net gain on Real Estate Venture transactions																										20,000,000		7,229,000		(417,000)
Advance received for refinancing																										195,000,000		89,000,000		0
Cash distribution from unconsolidated real estate ventures																										13,065,000		8,557,000		9,767,000
Proceeds from the sale of properties																										784,331,000		247,228,000		118,855,000
Gain (Loss) on Sale																										116,983,000		20,496,000		4,901,000
Carrying value of assets																						417,100,000				417,100,000		422,900,000
Net gain on sale of undepreciated real estate																										0		0		8,212,000
Net gain (loss) on real estate venture transactions																										20,000,000		7,418,000		(417,000)
Amount funded by corporate funds																										20,406,000		150,472,000		18,443,000
Proceeds from repayment of mortgage notes receivable																										0		88,000,000		$ 7,026,000
Real estate ventures aggregate indebtedness to third parties																						997,466,000				997,466,000		$ 794,571,000
TB-BDN Plymouth Apartments [Member]
Schedule Of Equity Method Investments [Line Items]
Construction Loan																						56,000,000				56,000,000
Guarantees, maximum exposure amount																						3,200,000				3,200,000
TB-BDN Plymouth Apartments [Member] | Subsequent Event [Member]
Schedule Of Equity Method Investments [Line Items]
Sale of ownership interest percentage																																		50.00%
Guarantee obligations cancelled																																		$ 3,200,000
1919 Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Guarantees, maximum exposure amount																						88,900,000				88,900,000
Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																														192,396
Number of Properties | property																																										2
Number of floors of a building | Storey																														3												3
Number of Properties Sold | property																														2
Broadmoor Austin Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²											1,112,236
Acreage of land | a											66
Number of Property units | property											7
Equity method investment percentage											50.00%
Payments to Acquire Land											$ 143,800,000
Encino Trace - Land [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																		320,000										320,000
Acreage of land | a																		54.1
Number of Properties | property																												2
Number of floors of a building																		4										4
Payments to Acquire Land																		$ 14,000,000
Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage											50.00%
Office Properties [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																												2,649,926		645,273								5,239,632
Number of Properties | property																																					93
Sales Price																						820,000,000				$ 820,000,000		$ 374,600,000		$ 101,150,000
Number of Properties Sold | property																										66		27		8
Proceeds from the sale of properties																										$ 769,799,000		$ 340,098,000		$ 113,024,000
Gain (Loss) on Sale																										116,983,000	[1]	22,002,000	[2],[3]	$ 4,646,000	[4]
Office Properties [Member] | Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																														192,396
Sales Price																														$ 20,750,000
Number of Properties Sold | property																														2
Proceeds from the sale of properties																														$ 34,392,000
Gain (Loss) on Sale	[4],[5]																													(255,000)
Office Properties [Member] | Broadmoor Austin Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Number of Properties | Building											7
Office Properties [Member] | 3141 Fairview Park Drive [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																																						587,317
Real Estate Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Management fees																										19,800,000		18,800,000
Accounts receivable																						1,400,000				1,400,000		1,700,000
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment																																							14
Equity Method Investments including net liabilities																						281,300,000				281,300,000
Investment in Real Estate Ventures, equity method	[6],[7]																					281,331,000				281,331,000		241,004,000
Real estate ventures aggregate indebtedness to third parties																						997,466,000				997,466,000
Unconsolidated Real Estate Ventures [Member] | Minimum [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																			20.00%
Unconsolidated Real Estate Ventures [Member] | Maximum [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																			70.00%
Unconsolidated Real Estate Ventures [Member] | Seven 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																																							7
Rentable Square Feet | ft²																																						8,000,000
Unconsolidated Real Estate Ventures [Member] | Two Real Estate Ventures [Member] | Undeveloped Land [Member]
Schedule Of Equity Method Investments [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment																																							2
Acreage of land | a																																								4.3
Unconsolidated Real Estate Ventures [Member] | Two Other Real Estate Ventures [Member] | Under Active Development Land [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] | Two Other Real Estate Ventures [Member] | Residential Tower One [Member]
Schedule Of Equity Method Investments [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment																																							1
Number of Property units																																					345				345
Unconsolidated Real Estate Ventures [Member] | Two Other Real Estate Ventures [Member] | Residential Tower Two [Member]
Schedule Of Equity Method Investments [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment																																							1
Number of Property units																																					321				321
Unconsolidated Real Estate Ventures [Member] | One Real Estate Venture [Member] | Apartment Complex [Member]
Schedule Of Equity Method Investments [Line Items]
Number of Unconsolidated Investments in Real Estate Ventures | Real_Estate_Investment																																							1
Number of Property units																																					398				398
Brandywine - AI Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																			50.00%	[8],[9]									50.00%
Investment in Real Estate Ventures, equity method	[9]																					67,809,000				67,809,000		50,760,000
Provision for impairment of investment in real estate ventures																										10,400,000
Effective interest rate	[9]																																		3.96%
Real estate ventures aggregate indebtedness to third parties	[9]																					131,539,000				131,539,000		132,717,000
Brandywine - AI Venture LLC [Member] | 3141 Fairview Park Drive [Member]
Schedule Of Equity Method Investments [Line Items]
Deconsolidated net assets			$ 45,600,000
Deconsolidated mortgage loan			20,600,000
Deconsolidated financing liability			12,400,000
Investment in Real Estate Ventures, equity method			$ 12,600,000
Recognizing gain or loss on sale																								$ 0
Capital funded to venture for mortgage debt																					$ 10,300,000
Repayment of mortgage debt																						20,600,000
Brandywine - AI Venture LLC [Member] | Station Square [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																																												497,896
Equity method investment percentage																																												50.00%
Provision for impairment of investment in real estate ventures																									$ 10,400,000
Number of Properties | property																																												3
Cost of equity method investment																																												$ 120,600,000
Equity method investment other than temporary impairment charge																									5,200,000
Brandywine - AI Venture LLC [Member] | Remaining Properties in Real Estate Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment other than temporary impairment charge																										0
Brandywine - AI Venture LLC [Member] | Current Creek Investments, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																													50.00%
Brandywine - AI Venture LLC [Member] | Office Properties [Member] | 3141 Fairview Park Drive [Member]
Schedule Of Equity Method Investments [Line Items]
Number of office properties owned | property																																													3
PJP V [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage		25.00%
Investment in Real Estate Ventures, equity method	[10]																					0				0		305,000
Proceeds from sale of real estate venture		$ 3,400,000
Equity in income (loss) of Real Estate Ventures		200,000
Net gain on Real Estate Venture transactions		$ 3,200,000
Real estate ventures aggregate indebtedness to third parties	[10]																					0				0		5,035,000
PJP V [Member] | Office Properties [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²		73,997
Invesco Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity in income (loss) of Real Estate Ventures				$ 0
Net gain on Real Estate Venture transactions				7,000,000
Amount of proceeds, net of closing costs				$ 7,000,000
1000 Chesterbrook [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage					50.00%																			50.00%
Proceeds from sale of real estate venture					$ 9,800,000
Net gain on Real Estate Venture transactions					3,200,000
Sales Price					32,100,000																			$ 32,100,000
Debt assumed by buyer					$ 23,200,000
Working capital contribution																					$ 200,000				$ 200,000
1000 Chesterbrook [Member] | One Real Estate Venture [Member] | Office Properties [Member]
Schedule Of Equity Method Investments [Line Items]
Area of Real Estate Property | ft²					172,286																			172,286
evo at Cira Centre South Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage							50.00%																																				30.00%
Investment in Real Estate Ventures, equity method							$ 28,300,000
Cost of equity method investment																																											$ 4,000,000
Number of floors of a building | Storey																																											33
Student housing bed capacity | Bed																																											850
Area of developed parcels of land (in acres) owned by a Real Estate Venture | a																																											1
Equity Method Investment, Underlying Equity in Net Assets																																											$ 8,500,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity																																											$ 4,500,000
Cash paid to acquire real estate ventures							$ 12,800,000
Equity method investment percentage of interests acquired by the Company and HSRE							30.00%
Construction Loan						$ 97,800,000
Debt instrument maturity date						Jul. 25, 2016
Cash distribution from unconsolidated real estate ventures						$ 6,300,000
Guarantor obligations, current carrying value																						52,500,000				$ 52,500,000
evo at Cira Centre South Venture [Member] | Secured Debt [Member]
Schedule Of Equity Method Investments [Line Items]
Debt instrument maturity date						Oct. 31, 2019
Term loans						$ 117,000,000
Debt instrument, description of variable rate basis																										LIBOR + 2.25
Debt instrument optional extended maturity date						Jun. 30, 2021
Advance received for refinancing						$ 105,000,000
Additional capacity under the term loan may be funded if certain criterion relating to the operating performance of the student housing tower are met						$ 12,000,000
evo at Cira Centre South Venture [Member] | Secured Debt [Member] | LIBOR [Member]
Schedule Of Equity Method Investments [Line Items]
Debt instrument, basis spread on variable rate						2.25%
evo at Cira Centre South Venture [Member] | Campus Crest Properties, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																											30.00%
evo at Cira Centre South Venture [Member] | HSRE, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage							50.00%																																				40.00%
Cash paid to acquire real estate ventures							$ 6,600,000
evo at Cira Centre South Venture [Member] | Maximum [Member] | Secured Debt [Member]
Schedule Of Equity Method Investments [Line Items]
Effective interest rate						5.25%
MAP Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[8],[11]																																		50.00%
Investment in Real Estate Ventures, equity method	[11]																					20,893,000				$ 20,893,000		0
Real estate ventures aggregate indebtedness to third parties	[11]																					180,800,000				180,800,000		0
MAP Venture [Member] | Variable Interest Entity, Not Primary Beneficiary [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²								3,924,783
Equity method investment percentage								50.00%
Sales Price								$ 398,100,000
Number of Properties Sold | property								58
Percentage of fee interests in land sold								100.00%
Ground lease annual payments																										$ 11,900,000
Ground lease annual rent expense increase percentage																																			2.50%
Reassessment period for change in ground lease annual payments																										10 years
Ground Lease Terms																										Annual payments by the MAP Venture, as tenant under the Ground Leases, initially total $11.9 million and increase 2.5% annually through November 2025.
Non-Recourse Debt								$ 180,800,000
Proceeds from the sale of properties								354,000,000
Ownership percentage value								$ 25,200,000
Coppell Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage									50.00%
Proceeds from sale of real estate venture									$ 4,600,000
Gain (Loss) on Sale									5,700,000
Real estate ventures aggregate indebtedness to third parties	[12]																					0				$ 0		15,515,000
Coppell Associates [Member] | Other Liabilities [Member]
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method									$ 1,100,000																			1,100,000
Residence Inn Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage										50.00%
Investment in Real Estate Ventures, equity method										$ 900,000												0	[10]			0	[10]	0	[10]
Proceeds from sale of real estate venture										6,100,000
Gain (Loss) on Sale										5,200,000
Real estate ventures aggregate indebtedness to third parties	[10]																					0				0		0
51 N 50 Patterson [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage												70.00%																							70.00%	[8]
Investment in Real Estate Ventures, equity method																						20,318,000				20,318,000		16,725,000
Payments to Acquire Land												$ 15,200,000
Area owned by real estate venture of undeveloped parcels of land | a												0.9
Real estate ventures aggregate indebtedness to third parties																						0				0		0
51 N 50 Patterson [Member] | JBG [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage												30.00%
Payments to Acquire Land												$ 6,500,000
1250 First Street Office [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage												70.00%																							70.00%	[8]
Investment in Real Estate Ventures, equity method																						17,304,000				17,304,000		14,312,000
Payments to Acquire Land												$ 13,200,000
Area owned by real estate venture of undeveloped parcels of land | a												0.5
Real estate ventures aggregate indebtedness to third parties																						0				0		0
1250 First Street Office [Member] | JBG [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage												30.00%
Payments to Acquire Land												$ 5,700,000
25 M Street [Member]
Schedule Of Equity Method Investments [Line Items]
Carrying value of assets										$ 20,500,000												22,400,000				22,400,000
GI Interchange Office LLC (DRA — N. PA) [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																																															1,611,961
Number of Properties | property																																															29
GI Interchange Office LLC (DRA — N. PA) [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																															20.00%
Brandywine Nineteen Nineteen Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																			50.00%	[8],[13],[14]										50.00%
Investment in Real Estate Ventures, equity method	[13],[14]																					27,462,000				$ 27,462,000		29,086,000
Area of developed parcels of land (in acres) owned by a Real Estate Venture | a																																														1
Debt instrument, description of variable rate basis																										LIBOR + 2.00
Payments to Acquire Land																																	$ 9,300,000
Remeasurement gain or loss on investments																$ 0
Real estate ventures aggregate indebtedness to third parties	[13],[14]																					79,250,000				$ 79,250,000		19,411,000
Brandywine Nineteen Nineteen Ventures [Member] | LCOR/CalSTRS [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage														50.00%
Aggregate gross sales price of a joint venture														$ 16,400,000
General Partners' Contributed Capital														5,200,000
Net gain on sale of undepreciated real estate														$ 8,200,000
Outstanding construction loan																						79,300,000				79,300,000
Equity method investments, Cash contributions																										29,600,000
Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²															590,881		232,274
Equity method investment percentage	[8],[13]																																		50.00%
Investment in Real Estate Ventures, equity method	[13]																					52,886,000				52,886,000		60,427,000
Number of Properties | property															7		2
Effective interest rate	[13]																																		3.36%
Equity method investments, Cash contributions															$ 18,900,000		$ 12,800,000
Equity method investments, Closing costs															200,000		100,000
Equity method investment, Consideration transferred																	48,200,000
Mortgage loans outstanding																	$ 34,500,000
Mortgage loans interest rate																	3.87%
Equity Method Investments Purchase Adjustments																	$ 900,000
Business acquisition cost of acquired entity transaction costs borne by seller																	600,000
Amount funded by corporate funds															128,100,000
Short-term Bank Loans and Notes Payable															$ 88,000,000
Real estate ventures aggregate indebtedness to third parties	[13]																					405,734,000				405,734,000		410,066,000
Austin Joint Venture [Member] | Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Non-Recourse Debt																																										$ 29,000,000
Austin Joint Venture [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																			50.00%
Area of Real Estate Property | ft²																			1,398,826
Aggregate gross sales price of a joint venture																			$ 330,000,000
Equity method investments, Cash contributions																	$ 6,400,000
Number of properties contributed to a joint venture | property																			7
Equity method investment, agreement to pay future capital expenditures																			$ 5,200,000													$ 800,000
Equity Method Investment, Additional Distribution Rights																																			10.00%
Net gain (loss) on real estate venture transactions																																$ 25,900,000
Austin Joint Venture [Member] | Brandywine Realty Trust [Member] | Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Net gain on Real Estate Venture transactions																														(200,000)
Aggregate gross sales price of a joint venture																																										41,500,000
Amount Of Participant Contribution																																										$ 5,900,000
Austin Joint Venture [Member] | DRA Advisors LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage																																			50.00%
Non-Recourse Debt																			230,600,000
Equity Method Investment, Distribution, Net of Initial Funding Agreement																			266,300,000
Amount Of Participant Contribution																			49,700,000
Equity method investments, Closing costs																			1,900,000
Closing Prorations and Lender Holdbacks																			6,900,000
Proceeds from Equity Method Investment, Dividends or Distributions																			$ 271,500,000
Austin Joint Venture [Member] | Office Properties [Member] | Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																																										192,396
Austin, Texas [Member]
Schedule Of Equity Method Investments [Line Items]
Number of floors of a building | Storey																	3
Austin, Texas [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment, agreement to pay future capital expenditures																														$ 4,400,000
River Place [Member]
Schedule Of Equity Method Investments [Line Items]
Proceeds from repayment of mortgage notes receivable													$ 88,000,000
4040 Wilson Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[8]																																		50.00%
Investment in Real Estate Ventures, equity method																						36,356,000				36,356,000		36,626,000
Capital funded to venture for mortgage debt																				$ 72,000,000
Number of Properties | property																				8
Area of Real Estate Property | ft²																				426,000
Area owned by real estate venture of undeveloped parcels of land | a																				1.3
Equity method investments, Cash contributions																				$ 36,000,000
Equity Method Investment, Budgeted Total Project Cost																				202,000,000
Real estate ventures aggregate indebtedness to third parties																						1,004,000				1,004,000		0
4040 Wilson Venture [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Cash paid to acquire real estate ventures																				36,000,000						35,600,000
4040 Wilson Venture [Member] | Ashton Park [Member]
Schedule Of Equity Method Investments [Line Items]
Fair value of land, net of amount encumbered																				$ 36,000,000
PJP VII [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[8]																																		25.00%
Investment in Real Estate Ventures, equity method																						980,000				980,000		872,000
Real estate ventures aggregate indebtedness to third parties																						4,956,000				4,956,000		$ 5,621,000
Guarantees, maximum exposure amount																						$ 400,000				$ 400,000
[1]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[2]	Gain on Sale is net of closing and other transaction related costs.
[3]	Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale.
[4]	Gain/(Loss) on sale is net of closing and other transaction related costs.
[5]	On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of approximately 192,396 net rentable square feet in Austin, Texas to an existing real estate venture (the “Austin Venture”) that the Company formed in 2013 with G&I VII Austin Office LLC, an investment vehicle advised by DRA Advisors LLC (“DRA”). The Company contributed the properties to the Austin Venture at an agreed upon value of $41.5 million. In conjunction with the contribution: (i) the Austin Venture obtained a $29.0 million mortgage loan; (ii) DRA contributed $5.9 million in net cash to the capital of the Austin Venture; and (iii) the Austin Venture distributed $34.4 million to the Company and credited the Company with a $5.9 million capital contribution to the Austin Venture. The Company incurred a $0.2 million loss on the contribution, driven primarily by closing costs.
[6]	Does not include the negative investment balance of one real estate venture totaling $1.1 million as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture on January 29, 2016. See “Coppell Associates” section below for further details.
[7]	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.
[8]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[9]	See “Brandywine AI Venture: 3141 Fairview Park Drive” section below for information discussing activity that occurred during 2016 relating to this venture.
[10]	The Company liquidated its 25% ownership interest in the PJP V real estate venture on September 22, 2016. On June 30, 2016, the Company liquidated its 50% ownership interest in the venture known as 1000 Chesterbrook. The ownership interest in Invesco, L.P. was sold prior to December 31, 2015, and on August 19, 2016, the Company assigned its residual profits interest to the general partner of Invesco. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2016 dispositions.
[11]	In order to fulfill interest rate protection requirements, a LIBOR interest rate cap of 1.75% was purchased, effective February 3, 2016 and maturing February 9, 2018, for a notional amount of $200.8 million. There are three options to extend the maturity date of the debt for three successive terms, each year representing a separate option.
[12]	Carrying amount represents the negative investment balance of the venture that was included in other liabilities as of December 31, 2015. The ownership interest in this venture was disposed of on January 29, 2016.
[13]	The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “Evo at Cira South Venture” section below for further details on these transactions.
[14]	The stated rate for the construction loan is LIBOR + 2.00%. It is further reduced to 1.75% upon reaching 90% residential occupancy and commencement of the lease in the retail space. To fulfill interest rate protection requirements, an interest rate cap was purchased at 4.50%.

Investment in Unconsolidated 77

Investment in Unconsolidated Real Estate Ventures - Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Sep. 22, 2016	Jun. 30, 2016	Jan. 29, 2016	Dec. 30, 2015	May 29, 2015	Dec. 20, 2011	Jan. 20, 2011
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method		$ 281,331		$ 241,004		$ 225,004
Equity Method Investments including net liabilities				239,874
Company’s share of income (loss) (Company’s basis)		(11,503)		(811)		$ (790)
Equity Method Investment Summarized Financial Information Debt		$ 997,466		794,571
Brandywine - AI Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%	[1],[2]									50.00%
Investment in Real Estate Ventures, equity method	[2]	$ 67,809		50,760
Company’s share of income (loss) (Company’s basis)	[2]	(5,895)		(229)
Equity Method Investment Summarized Financial Information Debt	[2]	$ 131,539		132,717
Debt Instrument, Interest Rate, Effective Percentage	[2]	3.96%
Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[3]	50.00%
Investment in Real Estate Ventures, equity method	[3]	$ 52,886		60,427
Company’s share of income (loss) (Company’s basis)	[3]	(1,880)		(1,235)
Equity Method Investment Summarized Financial Information Debt	[3]	$ 405,734		410,066
Debt Instrument, Interest Rate, Effective Percentage	[3]	3.36%
MAP Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[4]	50.00%
Investment in Real Estate Ventures, equity method	[4]	$ 20,893		0
Company’s share of income (loss) (Company’s basis)	[4]	(4,218)		0
Equity Method Investment Summarized Financial Information Debt	[4]	$ 180,800		0
Debt Instrument, Interest Rate Terms	[4]	L+6.25%
Debt Instrument, Maturity Date, Month and Year	[4]	2018-02
Four Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	65.00%
Investment in Real Estate Ventures, equity method		$ 2,286		1,684
Company’s share of income (loss) (Company’s basis)		602		211
Equity Method Investment Summarized Financial Information Debt		$ 9,961		10,162
Debt Instrument, Interest Rate, Effective Percentage		5.20%
Debt Instrument, Maturity Date, Month and Year		2021-02
PJP VII [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	25.00%
Investment in Real Estate Ventures, equity method		$ 980		872
Company’s share of income (loss) (Company’s basis)		233		211
Equity Method Investment Summarized Financial Information Debt		$ 4,956		5,621
Debt Instrument, Interest Rate Terms		L+2.65%
Debt Instrument, Maturity Date, Month and Year		2019-12
PJP Two [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	30.00%
Investment in Real Estate Ventures, equity method		$ 532		435
Company’s share of income (loss) (Company’s basis)		97		32
Equity Method Investment Summarized Financial Information Debt		$ 2,893		3,201
Debt Instrument, Interest Rate, Effective Percentage		6.12%
Debt Instrument, Maturity Date, Month and Year		2023-11
PJP VI [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	25.00%
Investment in Real Estate Ventures, equity method		$ 142		45
Company’s share of income (loss) (Company’s basis)		97		151
Equity Method Investment Summarized Financial Information Debt		$ 7,652		7,918
Debt Instrument, Interest Rate, Effective Percentage		6.08%
Debt Instrument, Maturity Date, Month and Year		2023-04
1000 Chesterbrook Blvd. [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage								50.00%
Investment in Real Estate Ventures, equity method	[5]	$ 0		1,895
Company’s share of income (loss) (Company’s basis)	[5]	160		117
Equity Method Investment Summarized Financial Information Debt	[5]	0		23,610
PJP V [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage							25.00%
Investment in Real Estate Ventures, equity method	[5]	0		305
Company’s share of income (loss) (Company’s basis)	[5]	127		189
Equity Method Investment Summarized Financial Information Debt	[5]	0		5,035
Invesco, L.P. [Member]
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method	[5]	0		0
Company’s share of income (loss) (Company’s basis)	[5]	261		349
Equity Method Investment Summarized Financial Information Debt	[5]	0		0
Broadmoor Austin Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method	[5]	0		0
Company’s share of income (loss) (Company’s basis)	[5]	0		(377)
Equity Method Investment Summarized Financial Information Debt	[5]	0		0
Coppell Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage									50.00%
Investment in Real Estate Ventures, at equity	[6]	0		(1,130)
Company’s share of income (loss) (Company’s basis)	[6]	12		84
Equity Method Investment Summarized Financial Information Debt	[6]	$ 0		15,515
HSRE BDN I, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[7]	50.00%
Investment in Real Estate Ventures, equity method	[7]	$ 21,228		15,003
Company’s share of income (loss) (Company’s basis)	[7]	843		(188)
Equity Method Investment Summarized Financial Information Debt	[7]	$ 105,000		95,562
Debt Instrument, Interest Rate Terms	[7]	L+2.25%
Debt Instrument, Maturity Date, Month and Year	[7]	2019-10
TB-BDN Plymouth Apartments [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	50.00%
Investment in Real Estate Ventures, equity method		$ 12,450		12,338
Company’s share of income (loss) (Company’s basis)		119		(252)
Equity Method Investment Summarized Financial Information Debt		$ 53,967		50,964
Debt Instrument, Interest Rate Terms		L+1.70%
Debt Instrument, Maturity Date, Month and Year		2017-12
Brandywine Nineteen Nineteen Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%	[1],[3],[8]										50.00%
Investment in Real Estate Ventures, equity method	[3],[8]	$ 27,462		29,086
Company’s share of income (loss) (Company’s basis)	[3],[8]	(1,529)		0
Equity Method Investment Summarized Financial Information Debt	[3],[8]	$ 79,250		19,411
Debt Instrument, Interest Rate Terms	[3],[8]	L+2.00%
Debt Instrument, Maturity Date, Month and Year	[3],[8]	2018-10
Residence Inn Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage										50.00%
Investment in Real Estate Ventures, equity method		$ 0	[5]	0	[5]					$ 900
Company’s share of income (loss) (Company’s basis)	[5]	0		367
Equity Method Investment Summarized Financial Information Debt	[5]	$ 0		0
4040 Wilson Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	50.00%
Investment in Real Estate Ventures, equity method		$ 36,356		36,626
Company’s share of income (loss) (Company’s basis)		(270)		(106)
Equity Method Investment Summarized Financial Information Debt		$ 1,004		0
Debt Instrument, Interest Rate Terms		L+2.40%
Debt Instrument, Maturity Date, Month and Year		2019-03
51 N 50 Patterson [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		70.00%	[1]								70.00%
Investment in Real Estate Ventures, equity method		$ 20,318		16,725
Company’s share of income (loss) (Company’s basis)		(114)		0
Equity Method Investment Summarized Financial Information Debt		$ 0		0
1250 First Street Office [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		70.00%	[1]								70.00%
Investment in Real Estate Ventures, equity method		$ 17,304		14,312
Company’s share of income (loss) (Company’s basis)		(15)		0
Equity Method Investment Summarized Financial Information Debt		$ 0		0
Seven Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	20.00%
Investment in Real Estate Ventures, equity method		$ 685		491
Company’s share of income (loss) (Company’s basis)		(133)		(135)
Equity Method Investment Summarized Financial Information Debt		$ 14,710		$ 14,789
Debt Instrument, Interest Rate, Effective Percentage		3.71%
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	See “Brandywine AI Venture: 3141 Fairview Park Drive” section below for information discussing activity that occurred during 2016 relating to this venture.
[3]	The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “Evo at Cira South Venture” section below for further details on these transactions.
[4]	In order to fulfill interest rate protection requirements, a LIBOR interest rate cap of 1.75% was purchased, effective February 3, 2016 and maturing February 9, 2018, for a notional amount of $200.8 million. There are three options to extend the maturity date of the debt for three successive terms, each year representing a separate option.
[5]	The Company liquidated its 25% ownership interest in the PJP V real estate venture on September 22, 2016. On June 30, 2016, the Company liquidated its 50% ownership interest in the venture known as 1000 Chesterbrook. The ownership interest in Invesco, L.P. was sold prior to December 31, 2015, and on August 19, 2016, the Company assigned its residual profits interest to the general partner of Invesco. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2016 dispositions.
[6]	Carrying amount represents the negative investment balance of the venture that was included in other liabilities as of December 31, 2015. The ownership interest in this venture was disposed of on January 29, 2016.
[7]	The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “Evo at Cira South Venture” section below for further details on these transactions
[8]	The stated rate for the construction loan is LIBOR + 2.00%. It is further reduced to 1.75% upon reaching 90% residential occupancy and commencement of the lease in the retail space. To fulfill interest rate protection requirements, an interest rate cap was purchased at 4.50%.

Investment in Unconsolidated 78

Investment in Unconsolidated Real Estate Ventures - Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss) (Parenthetical) (Details) $ in Thousands		Mar. 02, 2016USD ($)optionterm	Dec. 31, 2016USD ($)		Sep. 22, 2016	Jun. 30, 2016	Dec. 31, 2015USD ($)	Jun. 22, 2015	Dec. 20, 2011	Jan. 20, 2011
Schedule Of Equity Method Investments [Line Items]
Notional amount			$ 328,610				$ 328,610
Equity Method Investment Summarized Financial Information Debt			$ 997,466				794,571
Brandywine - Al Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage			50.00%	[1],[2]					50.00%
Debt Instrument, Interest Rate, Effective Percentage	[2]		3.96%
Equity Method Investment Summarized Financial Information Debt	[2]		$ 131,539				132,717
HSRE BDN I, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[1],[3]		50.00%
Equity Method Investment Summarized Financial Information Debt	[3]		$ 105,000				95,562
Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[1],[4]		50.00%
Debt Instrument, Interest Rate, Effective Percentage	[4]		3.36%
Equity Method Investment Summarized Financial Information Debt	[4]		$ 405,734				410,066
MAP Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[1],[5]		50.00%
Equity Method Investment Summarized Financial Information Debt	[5]		$ 180,800				0
PJP V [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage					25.00%
Equity Method Investment Summarized Financial Information Debt	[6]		0				5,035
1000 Chesterbrook Blvd. [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage						50.00%
Equity Method Investment Summarized Financial Information Debt	[6]		0				23,610
Broadmoor Austin Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Percentage of ownership interests								50.00%
Equity Method Investment Summarized Financial Information Debt	[6]		$ 0				0
Brandywine Nineteen Nineteen Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage			50.00%	[1],[4],[7]						50.00%
Debt Instrument, Interest Rate Terms			LIBOR + 2.00
Interest rate protection cap			4.50%
Interest rate upon 90% residential occupancy and commencement of lease in retail space			1.75%
Percentage of residential occupancy and commencement of lease in retail space			90.00%
Equity Method Investment Summarized Financial Information Debt	[4],[7]		$ 79,250				19,411
Seven Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage	[1]		20.00%
Debt Instrument, Interest Rate, Effective Percentage			3.71%
Equity Method Investment Summarized Financial Information Debt			$ 14,710				$ 14,789
Secured JV Debt [Member] | Brandywine - Al Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Number of Fixed Rate Mortgages			3
Secured JV Debt [Member] | Brandywine - Al Venture [Member] | Fixed rate loan maturing January 1, 2019 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 37,900
Debt Instrument, Interest Rate, Stated Percentage			4.40%
Debt Instrument Maturity Date			Jan. 1, 2019
Secured JV Debt [Member] | Brandywine - Al Venture [Member] | Fixed rate loan maturing January 1, 2022 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 27,100
Debt Instrument, Interest Rate, Stated Percentage			4.65%
Debt Instrument Maturity Date			Jan. 1, 2022
Secured JV Debt [Member] | Brandywine - Al Venture [Member] | Fixed rate loan maturing August 1, 2019 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 66,500
Debt Instrument, Interest Rate, Stated Percentage			3.22%
Debt Instrument Maturity Date			Aug. 1, 2019
Long-term Debt, Weighted Average Interest Rate			3.96%
Secured JV Debt [Member] | HSRE BDN I, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Equity method investment percentage		50.00%
Secured JV Debt [Member] | Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Number of Mortgages			7
Secured JV Debt [Member] | Austin Joint Venture [Member] | First mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 33,900
Debt Instrument Maturity Date			Nov. 1, 2018
Derivative, Fixed Interest Rate			1.59%
Debt Instrument, Interest Rate, Effective Percentage			3.52%
Derivative, Basis Spread on Variable Rate			1.93%
Secured JV Debt [Member] | Austin Joint Venture [Member] | Second mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 54,700
Debt Instrument Maturity Date			Oct. 15, 2018
Derivative, Fixed Interest Rate			1.49%
Debt Instrument, Interest Rate, Effective Percentage			3.19%
Derivative, Basis Spread on Variable Rate			1.70%
Secured JV Debt [Member] | Austin Joint Venture [Member] | Third mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 137,000
Debt Instrument Maturity Date			Nov. 1, 2018
Derivative, Fixed Interest Rate			1.43%
Debt Instrument, Interest Rate, Effective Percentage			3.44%
Derivative, Basis Spread on Variable Rate			2.01%
Secured JV Debt [Member] | Austin Joint Venture [Member] | Fourth mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 29,000
Debt Instrument, Interest Rate, Stated Percentage			4.50%
Debt Instrument Maturity Date			Apr. 6, 2019
Secured JV Debt [Member] | Austin Joint Venture [Member] | Fifth mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 34,300
Debt Instrument, Interest Rate, Stated Percentage			3.87%
Debt Instrument Maturity Date			Aug. 6, 2019
Secured JV Debt [Member] | Austin Joint Venture [Member] | Sixth mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 86,700
Debt Instrument Maturity Date			Feb. 10, 2020
Derivative, Fixed Interest Rate			1.36%
Debt Instrument, Interest Rate, Effective Percentage			3.36%
Derivative, Basis Spread on Variable Rate			2.00%
Secured JV Debt [Member] | Austin Joint Venture [Member] | Seventh mortgage - swapped to fixed [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Face Amount			$ 30,000
Debt Instrument Maturity Date			Jan. 1, 2021
Long-term Debt, Weighted Average Interest Rate			3.36%
Debt Instrument, Interest Rate Terms			LIBOR + 1.85
Interest rate protection cap			2.75%
Secured JV Debt [Member] | MAP Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument Maturity Date			Feb. 9, 2018
Interest rate protection cap		1.75%
Notional amount		$ 200,800
Debt instrument, number of options to extend maturity date | option		3
Debt instrument, number of successive terms | term		3
Secured JV Debt [Member] | Seven Tower Bridge [Member] | Mortgage Maturing March 2017 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			7.00%
Debt Instrument Maturity Date			Mar. 1, 2017
Debt Instrument, Number of Fixed Rate Mortgages			2
Equity Method Investment Summarized Financial Information Debt			$ 8,000
Secured JV Debt [Member] | Seven Tower Bridge [Member] | Fixed Rate Loan Maturing September 2025 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.00%
Debt Instrument Maturity Date			Sep. 1, 2025
Equity Method Investment Summarized Financial Information Debt			$ 800
Secured JV Debt [Member] | Seven Tower Bridge [Member] | Fixed Rate Loan Maturing February 2017 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.00%
Debt Instrument Maturity Date			Feb. 7, 2017
Equity Method Investment Summarized Financial Information Debt			$ 2,000
Secured JV Debt [Member] | Seven Tower Bridge [Member] | Fixed Rate Loan Maturing March 2020 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.25%
Debt Instrument Maturity Date			Mar. 11, 2020
Long-term Debt, Weighted Average Interest Rate			3.42%
Equity Method Investment Summarized Financial Information Debt			$ 3,900
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	See “Brandywine AI Venture: 3141 Fairview Park Drive” section below for information discussing activity that occurred during 2016 relating to this venture.
[3]	The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “Evo at Cira South Venture” section below for further details on these transactions
[4]	The basis differences associated with these ventures are allocated between cost and the underlying equity in the net assets of the investee and is accounted for as if the entity were consolidated (i.e., allocated to the Company’s relative share of assets and liabilities with an adjustment to recognize equity in earnings for the appropriate depreciation/amortization). The Company increased its ownership interest in the HSRE-BDN I, LLC venture (also referred to as the “Evo at Cira South Venture”) to 50% on March 2, 2016. On June 10, 2016, HSRE-BDN I, LLC refinanced its debt. See “Evo at Cira South Venture” section below for further details on these transactions.
[5]	In order to fulfill interest rate protection requirements, a LIBOR interest rate cap of 1.75% was purchased, effective February 3, 2016 and maturing February 9, 2018, for a notional amount of $200.8 million. There are three options to extend the maturity date of the debt for three successive terms, each year representing a separate option.
[6]	The Company liquidated its 25% ownership interest in the PJP V real estate venture on September 22, 2016. On June 30, 2016, the Company liquidated its 50% ownership interest in the venture known as 1000 Chesterbrook. The ownership interest in Invesco, L.P. was sold prior to December 31, 2015, and on August 19, 2016, the Company assigned its residual profits interest to the general partner of Invesco. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2016 dispositions.
[7]	The stated rate for the construction loan is LIBOR + 2.00%. It is further reduced to 1.75% upon reaching 90% residential occupancy and commencement of the lease in the retail space. To fulfill interest rate protection requirements, an interest rate cap was purchased at 4.50%.

Investment in Unconsolidated 79

Investment in Unconsolidated Real Estate Ventures - Summary of Financial Position of Real Estate Ventures (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]
Company’s share of equity (Company’s basis)		$ 281,331	$ 241,004	$ 225,004
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		1,483,067	1,258,999
Other assets		231,972	158,672
Other liabilities		129,486	69,028
Debt, net		989,738	794,571
Equity		595,815	554,072
Company’s share of equity (Company’s basis)	[1],[2]	$ 281,331	$ 241,004
[1]	Does not include the negative investment balance of one real estate venture totaling $1.1 million as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture on January 29, 2016. See “Coppell Associates” section below for further details.
[2]	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.

Investment in Unconsolidated 80

Investment in Unconsolidated Real Estate Ventures - Summary of Financial Position of Real Estate Ventures (Parenthetical) (Details) - USD ($) $ in Millions	Jan. 29, 2016	Dec. 31, 2015
Coppell Associates [Member] | Other Liabilities [Member]
Schedule Of Equity Method Investments [Line Items]
Investment in Real Estate Ventures, equity method	$ 1.1	$ 1.1

Investment in Unconsolidated 81

Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]
Equity in loss of Real Estate Ventures		$ (11,503)	$ (811)	$ (790)
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue		214,452	164,928	147,236
Operating expenses		(110,265)	(70,136)	(61,268)
Provision for impairment	[1]	(10,476)	0	0
Interest expense, net		(43,283)	(34,584)	(36,511)
Depreciation and amortization		(85,738)	(68,100)	(57,109)
Net loss	[2]	(35,310)	(7,892)	(7,652)
Equity in loss of Real Estate Ventures		$ (11,503)	$ (811)	$ (790)
[1]	During the year ended December 31, 2016, Brandywine - AI Venture LLC recorded a property level impairment charge of $10.4 million. See additional details in the “Station Square Impairment” disclosure below.
[2]	During the year ended December 31, 2016, there were $7.1 million of acquisition deal costs related to the formation of the MAP Venture.

Investment in Unconsolidated 82

Investment in Unconsolidated Real Estate Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Parenthetical) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Schedule Of Equity Method Investments [Line Items]
Provision for impairment of investment in real estate ventures	$ 7.3
Brandywine - AI Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Provision for impairment of investment in real estate ventures	10.4
MAP Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Acquisition deal costs	$ 7.1

Investment in Unconsolidated 83

Investment in Unconsolidated Real Estate Ventures - Aggregate Principal Payments of Recourse and Non-recourse Debt Payable to Third-parties (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Equity Method Investments [Line Items]
2,017	$ 304,931
2,018	331,601
2,019	7,360
2,020	86,978
2,021	6,099
Thereafter	1,291,679
Total principal payments	997,466	$ 794,571
Net deferred financing costs	(8,097)
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
2,017	72,520
2,018	485,847
2,019	274,445
2,020	92,261
2,021	40,498
Thereafter	31,895
Total principal payments	997,466
Net deferred financing costs	(7,728)
Outstanding indebtedness	$ 989,738	$ 794,571

Deferred Costs - Deferred Costs

Deferred Costs - Deferred Costs (Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Components of Deferred Costs Net [Abstract]
Leasing costs, Total Cost	$ 146,135	$ 165,741
Total Cost	149,730	169,319
Leasing costs, Accumulated Amortization	(56,942)	(67,342)
Total, Accumulated Amortization	(58,388)	(67,900)
Leasing costs, Deferred Costs, net	89,193	98,399
Financing costs, Deferred Costs, net	8,097
Deferred Costs	91,342	101,419
Revolving Credit Facility
Components of Deferred Costs Net [Abstract]
Financing costs, Total Cost	3,595	3,578
Financing costs, Accumulated Amortization	(1,446)	(558)
Financing costs, Deferred Costs, net	$ 2,149	$ 3,020

Deferred Costs (Textual) (Detai

Deferred Costs (Textual) (Details) $ in Thousands	1 Months Ended	8 Months Ended	12 Months Ended			20 Months Ended
	May 31, 2015ft²	Dec. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)
Deferred Costs (Textual) [Abstract]
Capitalized internal direct leasing costs			$ 5,000	$ 6,600	$ 7,100
2015 Lease [Member]
Deferred Costs (Textual) [Abstract]
Square feet of office space leased | ft²	228,000
Brokerage commission			4,200
2015 Lease [Member] | Chairman and Lead Independent Director [Member]
Deferred Costs (Textual) [Abstract]
Membership interest	33.30%
Brokerage commission		$ 500	$ 500			$ 1,000
2015 Lease [Member] | WDL Real Estate Advisory Group, LLC [Member]
Deferred Costs (Textual) [Abstract]
Membership interest	49.00%

Intangible Assets - Intangible

Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Intangible Assets [Line Items]
Intangible Assets, Total Cost	$ 160,681	$ 183,872
Intangible Assets, Accumulated Amortization	(88,203)	(72,249)
Intangible Assets, net	72,478	111,623
Acquired Lease Intangibles, Gross		48,956
Acquired Lease Intangibles, Accumulated Amortization		(23,301)
Acquired Lease Intangibles, Net	18,119	25,655
Below market leases [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross	37,579	50,025
Acquired Lease Intangibles, Accumulated Amortization	(19,460)	(24,178)
Acquired Lease Intangibles, Net	18,119	25,847
Liabilities of assets held for sale [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross		1,069
Acquired Lease Intangibles, Accumulated Amortization		(877)
Acquired Lease Intangibles, Net		192
In-place lease value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	142,889	161,276
Intangible Assets, Accumulated Amortization	(75,696)	(57,063)
Intangible Assets, net	67,193	104,213
Tenant relationship value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	13,074	20,117
Intangible Assets, Accumulated Amortization	(10,167)	(15,580)
Intangible Assets, net	2,907	4,537
Above market leases acquired [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	4,718	5,333
Intangible Assets, Accumulated Amortization	(2,340)	(1,879)
Intangible Assets, net	$ 2,378	3,454
Intangible assets including assets held for sale [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost		186,726
Intangible Assets, Accumulated Amortization		(74,522)
Intangible Assets, net		112,204
Assets held for sale [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost		2,854
Intangible Assets, Accumulated Amortization		(2,273)
Intangible Assets, net		$ 581

Intangible Assets (Textual) (De

Intangible Assets (Textual) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Tenant Move-Outs Prior to End of the Lease Term [Member]
Finite Lived Intangible Assets [Line Items]
Intangible Assets Written Off Through Accelerated Amortization	$ 0.6	$ 0.5	$ 0.8

Intangible Assets and Liabiliti

Intangible Assets and Liabilities - Annual Amortization of Intangible Assets, Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
2,017	$ 19,663
2,018	11,754
2,019	10,536
2,020	8,457
2,021	5,971
Thereafter	16,097
Intangible Assets, net	72,478	$ 111,623
Liabilities
2,017	3,323
2,018	2,196
2,019	1,885
2,020	1,337
2,021	807
Thereafter	8,571
Acquired Lease Intangibles, Net	$ 18,119	$ 25,655

Debt Obligations - Consolidated

Debt Obligations - Consolidated Debt Obligations Outstanding (Details) - USD ($) $ in Thousands		9 Months Ended	12 Months Ended		15 Months Ended
		Oct. 07, 2015	Dec. 31, 2016		Dec. 31, 2016		Apr. 02, 2016	Dec. 31, 2015	Oct. 08, 2015
Consolidated debt obligations
Plus: premiums/(discounts), net			$ (7,439)		$ (7,439)
Less: deferred financing costs			(8,097)		(8,097)
Total Debt Obligations			2,013,112		2,013,112			$ 2,384,717
Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			325,038		325,038			562,695
Plus: premiums/(discounts), net			(2,761)		(2,761)			(3,198)
Less: deferred financing costs			(728)		(728)			(13,744)
Total mortgage indebtedness			321,549		321,549			545,753
Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			1,703,610		1,703,610			1,853,529
Plus: premiums/(discounts), net			(4,678)		(4,678)			(5,714)
Less: deferred financing costs			(7,369)		(7,369)			(8,851)
Total unsecured indebtedness			1,691,563		1,691,563			1,838,964
Effective interest rate							6.00%
3141 Fairview Eleven Tower [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	[1]		$ 0		$ 0			20,838
Effective interest rate	[1]		4.25%		4.25%
Debt instrument maturity date	[1]		Jan. 1, 2017
Two Logan Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 86,012		$ 86,012			86,886
Effective interest rate	[2]		3.98%		3.98%
Debt instrument maturity date			May 1, 2020
One Commerce Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 127,026		$ 127,026			$ 130,000
Effective interest rate			3.64%	[3]	3.64%	[3]		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			$ 112,000
Effective interest rate	[4]		4.51%		4.51%
Debt instrument maturity date			Apr. 5, 2023
IRS Philadelphia Campus [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	[5]		$ 0		$ 0			177,425
Effective interest rate	[5]		7.00%		7.00%
Debt instrument maturity date	[5]		Sep. 10, 2030
Cira South Garage [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	[5]		$ 0		$ 0			35,546
Effective interest rate	[5]		7.12%		7.12%
Debt instrument maturity date	[5]		Sep. 10, 2030
Seven Year Term Loan - Swapped to fixed [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross		$ 200,000	$ 250,000		$ 250,000			250,000	$ 250,000
Effective interest rate			3.72%		3.72%				3.72%
Debt instrument maturity date		Feb. 1, 2019	Oct. 1, 2022		Oct. 8, 2022
$250.0M 6.00% Guaranteed Notes due 2016 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	[6]		$ 0		$ 0			149,919
Effective interest rate	[6]		5.95%		5.95%
Debt instrument maturity date	[6]		Apr. 1, 2016
$300.0M 5.70% Guaranteed Notes due 2017 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 300,000		$ 300,000			300,000
Effective interest rate			5.68%		5.68%
Debt instrument maturity date			May 1, 2017
$325.0M 4.95% Guaranteed Notes due 2018 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 325,000		$ 325,000			325,000
Effective interest rate			5.13%		5.13%
Debt instrument maturity date			Apr. 15, 2018
$250M 3.95% Guaranteed Notes due 2023 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 250,000		$ 250,000			250,000
Effective interest rate			4.02%		4.02%
Debt instrument maturity date			Feb. 15, 2023
250.0M 4.10% Guaranteed Notes due 2024 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 250,000		$ 250,000			250,000
Effective interest rate			4.33%		4.33%
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			250,000
Effective interest rate			4.60%		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			27,062
Effective interest rate			2.75%		2.75%
Debt instrument maturity date			Mar. 30, 2035
Indenture IB (Preferred Trust I) [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 25,774		$ 25,774			25,774
Effective interest rate			3.30%		3.30%
Debt instrument maturity date			Apr. 30, 2035
Indenture II (Preferred Trust II) [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross			$ 25,774		$ 25,774			$ 25,774
Effective interest rate			3.09%		3.09%
Debt instrument maturity date			Jul. 30, 2035
[1]	On August 31, 2016, the Company deconsolidated 3141 Fairview Park Drive and began accounting for it under the equity method of accounting as part of Brandywine - AI Venture LLC, an unconsolidated real estate venture in which the Company holds a 50% interest. At December 31, 2015, this balance represented the full debt amount of the property, as it was consolidated at that time. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further details.
[2]	On April 7, 2016, the Company closed on an $86.9 million first mortgage financing on Two Logan Square, a 708,844-square foot office property located in Philadelphia, Pennsylvania. Proceeds of the loan were used to repay, without penalty, the $86.6 million principal balance of the former Two Logan Square first mortgage loan, which had a 7.57% effective interest rate.
[3]	This loan was assumed upon acquisition of the related properties on December 19, 2013. On December 29, 2015, the Company refinanced the debt increasing the principal balance to $130.0 million and extended the term from the scheduled maturity from January 6, 2016 to April 5, 2023. The effective interest rate as of December 31, 2015 was 3.64%. A default under this loan will also constitute a default under the loan outstanding on Two Commerce Square. This loan is also secured by a lien on Two Commerce Square.
[4]	This loan was assumed upon acquisition of the related property on December 19, 2013. The interest rate reflects the market rate at the time of acquisition. A default under this loan will also constitute a default under the loan outstanding on One Commerce Square. This loan is also secured by a lien on One Commerce Square.
[5]	On January 14, 2016, the Company funded $265.8 million to prepay two mortgage loans, consisting of $176.9 million of principal repayment, $44.5 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness on the office property located at 2970 Market Street in Philadelphia, Pennsylvania commonly known as 30th Street Main Post Office (“Cira Square”), ahead of its scheduled maturity date of September 10, 2030. Also on January 14, 2016, the Company funded $44.4 million, consisting of $35.5 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness of a 1,662 parking space facility located in Philadelphia, Pennsylvania commonly known as (“Cira South Garage”), ahead of its scheduled maturity date of September 10, 2030. These repayments were financed with $195.0 million of funds available under the Credit Facility with the remaining balance funded through available cash balances. The Company recognized a $66.6 million loss on extinguishment of debt, consisting of the prepayment charges along with $10.8 million and $2.4 million related to non-cash charges for deferred financing costs for Cira Square and Cira South Garage, respectively.
[6]	On April 1, 2016, the entire principal balance of the unsecured 6.00% Guaranteed Notes was repaid upon maturity. Available cash balances were used to fund the repayment of the unsecured notes.

Debt Obligations - Consolidat90

Debt Obligations - Consolidated Debt Obligations Outstanding (Parenthetical) (Details)		Apr. 07, 2016USD ($)ft²	Jan. 14, 2016USD ($)ft²	Dec. 29, 2015USD ($)	Dec. 31, 2016USD ($)		Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Apr. 02, 2016	Dec. 20, 2011
Debt Instrument [Line Items]
Mortgage notes payable, net					$ 321,549,000		$ 545,753,000
Extinguishment of Debt, Amount					0		0	$ 376,174,000
Loss on early extinguishment of debt - deferred financing costs								152,000
Loss on early extinguishment of debt			$ (66,600,000)		(66,590,000)		0	$ (7,594,000)
Unsecured Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of debt			195,000,000
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					325,038,000		562,695,000
Extinguishment of Debt, Amount			44,400,000
Repayments of debt			35,500,000
Repayment of prepayment charges			8,900,000
Secured Debt [Member] | Cira Square and Cira South Garage [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount			$ 265,800,000
Secured Debt [Member] | Cira Square [Member]
Debt Instrument [Line Items]
Debt instrument maturity date			Sep. 10, 2030
Repayments of debt			$ 176,900,000
Repayment of prepayment charges			44,500,000
Loss on early extinguishment of debt - deferred financing costs			$ 10,800,000
Secured Debt [Member] | Cira South Garage [Member]
Debt Instrument [Line Items]
Debt instrument maturity date			Sep. 10, 2030
Extinguishment of Debt, Amount			$ 44,400,000
Repayments of debt			35,500,000
Repayment of prepayment charges			$ 8,900,000
Number of Parking Spaces | ft²			1,662
Loss on early extinguishment of debt - deferred financing costs			$ 2,400,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					$ 1,703,610,000		1,853,529,000
Effective interest rate									6.00%
First Mortgage [Member] | Mortgage Loans over $1,000,000 [Member] | Office Building at Two Logan Square [Member]
Debt Instrument [Line Items]
Mortgage notes payable, net		$ 86,900,000
Net Rentable Square Feet | ft²		708,844
Former First Mortgage [Member] | Mortgage Loans over $1,000,000 [Member] | Office Building at Two Logan Square [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 86,600,000
Loan interest rate		7.57%
Brandywine - AI Venture LLC [Member]
Debt Instrument [Line Items]
Equity method investment percentage					50.00%	[1],[2]				50.00%
Effective interest rate	[2]				3.96%
3141 Fairview Eleven Tower [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	[3]				$ 0		20,838,000
Debt instrument maturity date	[3]				Jan. 1, 2017
Effective interest rate	[3]				4.25%
3141 Fairview Eleven Tower [Member] | Brandywine - AI Venture LLC [Member]
Debt Instrument [Line Items]
Equity method investment percentage					50.00%
One Commerce Square [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross					$ 127,026,000		$ 130,000,000
Debt instrument increase in principal				$ 130,000,000
Debt instrument maturity date					Apr. 5, 2023
Effective interest rate					3.64%	[4]	3.64%
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	See “Brandywine AI Venture: 3141 Fairview Park Drive” section below for information discussing activity that occurred during 2016 relating to this venture.
[3]	On August 31, 2016, the Company deconsolidated 3141 Fairview Park Drive and began accounting for it under the equity method of accounting as part of Brandywine - AI Venture LLC, an unconsolidated real estate venture in which the Company holds a 50% interest. At December 31, 2015, this balance represented the full debt amount of the property, as it was consolidated at that time. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further details.
[4]	This loan was assumed upon acquisition of the related properties on December 19, 2013. On December 29, 2015, the Company refinanced the debt increasing the principal balance to $130.0 million and extended the term from the scheduled maturity from January 6, 2016 to April 5, 2023. The effective interest rate as of December 31, 2015 was 3.64%. A default under this loan will also constitute a default under the loan outstanding on Two Commerce Square. This loan is also secured by a lien on Two Commerce Square.

Debt Obligations (Textual) (Det

Debt Obligations (Textual) (Details) - USD ($)	Jan. 14, 2016	Oct. 08, 2015	May 12, 2015	Sep. 16, 2014	Oct. 07, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Apr. 02, 2016	May 15, 2015
Debt Instrument [Line Items]
Extinguishment of Debt, Amount						$ 0	$ 0	$ 376,174,000
Loss on early extinguishment of debt	$ (66,600,000)					(66,590,000)	0	(7,594,000)
Loss on early extinguishment of debt - deferred financing costs								152,000
Recognized hedge activity						$ 0	$ 0	$ (828,000)
New Credit Facility [Member] | Revolving Credit Facility
Debt Instrument [Line Items]
Debt term			4 years
Maximum borrowing capacity											$ 600,000,000
Increase in limit											400,000,000
Minimum Credit Spread on a LIBOR Rate Loan						0.00%
Maximum Credit Spread on a LIBOR Rate Loan						0.55%
Commitment fee percentage						0.25%
Minimum fixed charge coverage ratio						1.5
Maximum leverage ratio						0.60
Maximum unsecured indebtedness to unencumbered asset value ratio						0.60
Maximum secured indebtedness to total asset value ratio						0.40
Minimum unencumbered cash flow to interest expense on unsecured debt ratio						1.75
Maximum percent of payments of dividends and distributions						95.00%
New Credit Facility [Member] | Revolving Credit Facility | Minimum [Member]
Debt Instrument [Line Items]
Commitment fee percentage						0.125%
New Credit Facility [Member] | Revolving Credit Facility | Maximum [Member]
Debt Instrument [Line Items]
Commitment fee percentage						0.30%
New Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity											65,000,000
New Credit Facility [Member] | Swing-Loans [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity											$ 60,000,000
New Credit Facility [Member] | LIBOR [Member] | Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate						1.20%
Basis spread on variable rate						1.00%
New Credit Facility [Member] | LIBOR [Member] | Revolving Credit Facility | Minimum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate						0.875%
New Credit Facility [Member] | LIBOR [Member] | Revolving Credit Facility | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate						1.55%
New Credit Facility [Member] | Federal Funds Rate [Member] | Revolving Credit Facility
Debt Instrument [Line Items]
Basis spread on variable rate						0.50%
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate						4.03%	5.72%	5.73%	4.03%
Long-term Debt, Gross						$ 325,038,000	$ 562,695,000		$ 325,038,000
Extinguishment of Debt, Amount	$ 44,400,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						1,703,610,000	1,853,529,000		1,703,610,000
Recognized hedge activity				$ 800,000
Effective interest rate										6.00%
Unsecured Debt [Member] | 250.0M 4.10% Guaranteed Notes due 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						250,000,000	250,000,000		250,000,000
Debt instrument, Unamortized discount, Percent of face amount				99.388%
Debt instrument, Yield to maturity				4.175%
Debt instrument, Yield to maturity spread at time of pricing				1.70%
Debt Instrument, Unamortized Discount						$ 1,200,000	1,300,000		$ 1,200,000
Debt Instrument Maturity Date						Oct. 1, 2024
Effective interest rate						4.33%			4.33%
Unsecured Debt [Member] | $250M 4.55% Guaranteed Notes due 2029 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross						$ 250,000,000	250,000,000		$ 250,000,000
Debt instrument, Unamortized discount, Percent of face amount				99.191%
Debt instrument, Yield to maturity				4.625%
Debt instrument, Yield to maturity spread at time of pricing				2.15%
Debt Instrument, Unamortized Discount						$ 1,700,000	1,800,000		$ 1,700,000
Debt Instrument Maturity Date						Oct. 1, 2029
Effective interest rate						4.60%			4.60%
Unsecured Debt [Member] | Notes 2024 and 2029 [Member]
Debt Instrument [Line Items]
Proceeds from Notes Payable				$ 492,900,000
Unsecured Debt [Member] | $250.0M 5.400% Guaranteed Notes due 2014 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						5.40%			5.40%
Extinguishment of Debt, Amount				75,100,000
Debt Instrument, Repurchased Face Amount				143,500,000
Debt Instrument, Redemption, Description						$1,026.88 per $1,000
Unsecured Debt [Member] | 7.50% Guaranteed Notes due May 15, 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						7.50%			7.50%
Extinguishment of Debt, Amount				42,700,000
Loss on early extinguishment of debt								$ 5,000,000
Debt Instrument, Repurchased Face Amount				114,900,000
Debt Instrument, Redemption, Description						$1,070.24 per $1,000
Unsecured Debt [Member] | Notes 2015 and 2015 [Member]
Debt Instrument [Line Items]
Loss on early extinguishment of debt								$ 2,600,000
Unsecured Debt [Member] | Three Year Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount				$ 150,000,000
Debt Instrument Maturity Date				Feb. 1, 2015
Unsecured Debt [Member] | Four-Year Term Loan - Swapped to fixed [Member]
Debt Instrument [Line Items]
Debt Instrument, Repurchased Face Amount				$ 100,000,000
Unsecured Debt [Member] | Four-Year Term Loan - Variable [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date				Feb. 1, 2016
Unsecured Debt [Member] | Three and Four Year Term Loan [Member]
Debt Instrument [Line Items]
Loss on early extinguishment of debt - deferred financing costs				$ 300,000
Unsecured Debt [Member] | Seven Year Term Loan - Swapped to fixed [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 250,000,000			$ 200,000,000	$ 250,000,000	$ 250,000,000		$ 250,000,000
Debt Instrument Maturity Date					Feb. 1, 2019	Oct. 1, 2022			Oct. 8, 2022
Increase in debt		50,000,000
Increase in limit		$ 150,000,000
Effective interest rate		3.72%				3.72%			3.72%
Unsecured Debt [Member] | Seven Year Term Loan - Swapped to fixed [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate		1.80%
Unsecured Debt [Member] | New Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date						May 15, 2019

Debt Obligations - Additional I

Debt Obligations - Additional Information on Repurchase of Outstanding Unsecured Notes (Details) - USD ($)	Jan. 14, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Extinguishment Of Debt [Line Items]
Principal		$ 0	$ 0	$ 376,174,000
Repurchase Amount		149,919,000	0	383,768,000
Loss on Early Extinguishment of Debt	$ (66,600,000)	$ (66,590,000)	$ 0	(7,594,000)
Acceleration of Deferred Financing				152,000
$250.0M 5.400% Guaranteed Notes due 2014 [Member]
Extinguishment Of Debt [Line Items]
Principal				218,549,000
Repurchase Amount				219,404,000
Loss on Early Extinguishment of Debt				(855,000)
Acceleration of Deferred Financing				9,000
7.50% Guaranteed Notes due May 15, 2015 [Member]
Extinguishment Of Debt [Line Items]
Principal				157,625,000
Repurchase Amount				164,364,000
Loss on Early Extinguishment of Debt				(6,739,000)
Acceleration of Deferred Financing				$ 143,000

Debt Obligations - Aggregate Sc

Debt Obligations - Aggregate Scheduled Principal Payments of Debt Obligation, Excluding Amortization of Discounts and Premiums (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Debt Disclosure [Abstract]
2,017	$ 304,931
2,018	331,601
2,019	7,360
2,020	86,978
2,021	6,099
Thereafter	1,291,679
Total principal payments	2,028,648
Net unamortized premiums/(discounts)	(7,439)
Less: deferred financing costs	(8,097)
Total Debt Obligations	$ 2,013,112	$ 2,384,717

Fair Value of Financial Instr94

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage notes payable, net		$ 321,549	$ 545,753
Note receivable		3,400
Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable	[1]	3,380
Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Note receivable, fair value	[1]	3,717
Unsecured Notes Payable [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Unsecured notes payable		1,364,854	1,512,554
Unsecured Notes Payable [Member] | Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		1,372,758	1,529,346
Variable Rate Debt [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate debt		326,709	326,410
Variable Rate Debt [Member] | Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		307,510	305,522
Mortgages Notes Payable [Member] | Carrying Amount [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage notes payable, net		321,549	545,753
Mortgages Notes Payable [Member] | Fair Value [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Debt instrument, fair value		$ 328,853	$ 597,377
[1]	The inputs to originate the loan 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. See Note 2, “Significant Accounting Policies,” for further information regarding the note origination.

Fair Value of Financial Instr95

Fair Value of Financial Instruments (Textual) (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Variable rate and mortgage debt [Member]
Fair Value Inputs Liabilities Quantitative Information [Line Items]
Discount Rates	4.353%	4.55%

Risk Management and Use of De96

Risk Management and Use of Derivative Financial Instruments - Terms and Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivatives Fair Value [Line Items]
Notional Amount	$ 328,610	$ 328,610
3.718% Interest Rate Swap Maturing October 8, 2022 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.718%
Derivative Asset, Notional Amount	$ 250,000	250,000
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	3,733	1,884
3.300% Interest Rate Swap Maturing January 30, 2021 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Notional Amount	$ 25,774	25,774
Derivative, Fixed Interest Rate	3.30%
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ (300)	(531)
3.090% Interest Rate Swap Maturing October 30, 2019 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Notional Amount	$ 25,774	25,774
Derivative, Fixed Interest Rate	3.09%
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ (214)	(388)
2.750% Interest Rate Swap Maturing September 30, 2017 [Member] | Cash Flow Hedging [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Notional Amount	$ 27,062	27,062
Derivative, Fixed Interest Rate	2.75%
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ (83)	$ (201)

Risk Management and Use of De97

Risk Management and Use of Derivative Financial Instruments (Textual) (Details) - Customer	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Rental Revenue [Member] | Customer Concentration Risk [Member]
Derivatives Fair Value [Line Items]
Number of tenant accounted for 10% or more of the Company's rents	0	0	0

Discontinued Operations (Textua

Discontinued Operations (Textual) (Details) $ in Thousands, ft² in Millions	12 Months Ended
	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)ft²property
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net gain on disposition of discontinued operations	$ 0	$ 0	$ 900
Discontinued Operations [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net gain on disposition of discontinued operations			$ 900
Net Rentable Space Sold | ft²			1.1
Number of properties sold post closing activity (in properties) | property			14
Princeton Pike Corporate Center [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net gain on disposition of discontinued operations			$ 900

Discontinued Operations - Summa

Discontinued Operations - Summary of Revenue and Expense Information for Properties Sold which Qualify for Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue:
Rents									$ 421,505	$ 486,731	$ 483,682
Tenant reimbursements									70,629	85,722	84,879
Other									4,316	6,617	3,221
Total revenue	$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	525,463	602,631	596,982
Expenses:
Property operating expenses									152,926	181,170	177,330
Real estate taxes									46,252	50,623	51,844
Depreciation and amortization									189,676	219,029	208,569
Interest income									1,236	1,224	3,974
Income from discontinued operations before gain on sale of interests in real estate									0	0	18
Net gain on disposition of discontinued operations									0	0	900
Total discontinued operations									$ 0	$ 0	918
Discontinued Operations [Member]
Revenue:
Rents											0
Tenant reimbursements											26
Other											0
Total revenue											26
Expenses:
Property operating expenses											8
Real estate taxes											0
Depreciation and amortization											0
Total operating expenses											8
Interest income											0
Income from discontinued operations before gain on sale of interests in real estate											18
Net gain on disposition of discontinued operations											900
Total discontinued operations											$ 918

Limited Partners' Non-Contro100

Limited Partners' Non-Controlling Interests in the Parent Company (Textual) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Noncontrolling Interest [Abstract]
Aggregate amount related to non-controlling interests classified within equity	$ 14.9	$ 16.1
Settlement value of non controlling interest in operating partnership	$ 24.4	$ 21

Beneficiaries Equity of the 101

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								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator
Income (Loss) from continuing operations, Basic									$ 40,501	$ (30,740)	$ 6,024
Net (income) loss from continuing operations attributable to non-controlling interests - consolidated real estate ventures									(310)	339	43
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(341)	(329)	(349)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Income (Loss) from continuing operations available to common Shareholders, Basic									32,950	(37,630)	(1,182)
Income from discontinued operations									0	0	908
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust									32,950	(37,630)	(274)
Net income (loss) from continuing operations attributable to non-controlling interests, Diluted									(310)	339	43
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(341)	(329)	(349)
Income (loss) from continuing operations available to common shareholders, Diluted									32,950	(37,630)	(1,182)
Income (loss) from discontinued operations, Diluted									0	0	908
Net income (loss) attributable to common shareholders, Diluted									$ 32,950	$ (37,630)	$ (274)
Denominator
Basic weighted average shares outstanding (in shares)									175,018,163	178,162,160	166,202,649
Contingent securities/Share based compensation (in shares)									992,651	0	0
Diluted weighted average shares outstanding (in shares)									176,010,814	178,162,160	166,202,649
Earnings (loss) per Common Share:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	0.19	(0.21)	0
Income (loss) from continuing operations attributable to common shareholders, Diluted (USD per share)									0.19	(0.21)	(0.01)
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ 0.19	$ (0.21)	$ 0

Beneficiaries Equity of the 102

Beneficiaries Equity of the Parent Company (Textual) (Details) - USD ($)	Dec. 06, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 22, 2015
Class of Stock [Line Items]
Dividends, Common Stock	$ 28,100,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Dividends, Preferred Stock		$ 6,900,000	$ 6,900,000	$ 6,900,000
Authorized Amount					$ 100,000,000
Number of shares available for repurchase under the preexisting share repurchase program					539,200
Repurchased and Retired, Shares		0	5,209,437
Share Price			$ 12.90
Repurchased and Retired, Value			$ 67,325,000
Common stock price per share		$ 0.01	$ 0.01
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage		6.90%
Preferred Stock, Liquidation Preference Per Share		$ 25
Dividends, Preferred Stock	$ 1,700,000
Dividend Declared [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share	$ 0.16
Redeemable Common Limited Partnership Units
Class of Stock [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share		1,479,799	1,535,102	1,535,102

Partners Equity of the Opera103

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								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Numerator
Income (Loss) from continuing operations, Basic									$ 40,501	$ (30,740)	$ 6,024
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(341)	(329)	(349)
Distribution to preferred shareholders									(6,900)	(6,900)	(6,900)
Income (loss) from discontinued operations, Basic									0	0	918
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									$ (341)	$ (329)	$ (349)
Denominator
Basic weighted average shares outstanding (in shares)									175,018,163	178,162,160	166,202,649
Contingent securities/Share based compensation (in shares)									992,651	0	0
Diluted weighted average shares outstanding (in shares)									176,010,814	178,162,160	166,202,649
Earnings (loss) per Common Share:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	0.19	(0.21)	0
Income (loss) from continuing operations attributable to common shareholders, Diluted (USD per share)									0.19	(0.21)	(0.01)
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	(0.08)	0.03	(0.02)	0.25	(0.37)	0.10	0.01	0.04	$ 0.19	$ (0.21)	$ 0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from continuing operations, Basic									$ 40,501	$ (30,740)	$ 6,024
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(341)	(329)	(349)
Distribution to preferred shareholders									(6,900)	(6,900)	(6,900)
Net (income) loss attributable to non-controlling interests									(15)	3	44
Income (loss) from continuing operations available to common unitholders, Basic									33,245	(37,966)	(1,181)
Income (loss) from discontinued operations, Basic									0	0	918
Net income (loss) attributable to common unitholders, Basic									33,245	(37,966)	(263)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(341)	(329)	(349)
Income (loss) from continuing operations available to common unitholders, Diluted									33,245	(37,966)	(1,181)
Income (loss) from discontinued operations, diluted									0	0	918
Net income attributable to common unitholders, Diluted									$ 33,245	$ (37,966)	$ (263)
Denominator
Basic weighted average shares outstanding (in shares)									176,523,800	179,697,262	167,942,246
Contingent securities/Share based compensation (in shares)									992,651	0	0
Diluted weighted average shares outstanding (in shares)									177,516,451	179,697,262	167,942,246
Earnings (loss) per Common Share:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ 0.19	$ (0.21)	$ (0.01)
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Basic (USD per share)	(0.08)	0.03	(0.02)	0.25	(0.36)	0.10	0.04	0.04	0.19	(0.21)	0
Income (loss) from continuing operations attributable to common shareholders, Diluted (USD per share)									0.19	(0.21)	(0.01)
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0	0.01
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.36)	$ 0.10	$ 0.04	$ 0.04	$ 0.19	$ (0.21)	$ 0

Partners Equity of the Opera104

Partners Equity of the Operating Partnership (Textual) (Details) - USD ($)	Dec. 06, 2016	Dec. 31, 2016	Dec. 31, 2015	Jul. 22, 2015	Dec. 31, 2014
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 30,032,000	$ 28,249,000		$ 28,871,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Authorized Amount				$ 100,000,000
Number of Shares Authorized to be Repurchased				539,200
Repurchased and Retired, Shares		0	5,209,437
Share Price			$ 12.90
Repurchased and Retired, Value			$ 67,325,000
Common Stock, Par or Stated Value Per Share (USD per share)		$ 0.01	$ 0.01
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 30,032,000	$ 28,249,000		$ 28,871,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Repurchase program, number of mirror unit retired for each common share repurchased		1
Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.16
Dividend Declared [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.16
Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 28,100,000
Class A Units [Member]
Earnings Per Common Partnership Unit [Line Items]
Redeemable Limited Partnership Units Potential Cash Redemption Value Closing Market Price		$ 16.51	$ 13.66		$ 15.98
Limited Partners' Capital Account, Units Outstanding		1,479,799	1,535,102		1,535,102
6.90% Series E-linked Preferred Units [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Preferred Stock, Dividend Rate, Percentage		6.90%
Preferred Stock, Liquidation Preference Per Share		$ 25
6.90% Series E-linked Preferred Units [Member] | Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Dividends, Preferred Stock, Cash	$ 1,700,000

Share Based Compensation, 40105

Share Based Compensation, 401(k) Plan and Deferred Compensation (Textual) (Details)	May 24, 2016shares	Mar. 08, 2016Installmentshares	Feb. 22, 2016shares	Feb. 01, 2016shares	Dec. 31, 2016USD ($)shares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)	Feb. 05, 2016$ / shares	Feb. 23, 2015shares	Mar. 12, 2014shares	Mar. 11, 2014shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | shares					2,377,778	2,624,067
Share-based compensation expense					$ 5,600,000	$ 7,300,000	$ 6,100,000
Share-based compensation expense, capitalized					1,000,000	1,900,000	1,700,000
Defined Contribution Plan, Employer Discretionary Contribution Amount					$ 400,000	$ 400,000	400,000
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent					100.00%
Number of shares to be issued under deferred compensation plan included in total shares outstanding | shares					800,000	700,000
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | shares					2,377,778
Share-based compensation expense					$ 0	$ 0
Share-based compensation expense, capitalized					0	0
Restricted Share Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense					2,600,000	2,400,000	2,700,000
Share-based compensation expense, capitalized					$ 400,000	$ 700,000	600,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number | shares					488,604	506,147
Vesting period					3 years
Unrecognized compensation expenses					$ 2,100,000
Weighted average period over which options will be recognized					1 year 4 months 24 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					three years from the initial grant dates
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares					227,845
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 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 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 | shares		54,168
Number of Vesting Installments | Installment		3
Restricted Share 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 | shares			141,358
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date			Apr. 15, 2019
Restricted Share Awards [Member] | Vest Ratably Over Three Years [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares	32,319
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights					ratably over three years
Restricted Share 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, 2017
Restricted Share 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, 2018
Restricted Share 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, 2019
Restricted Performance Share Units Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense					$ 2,800,000	$ 4,200,000	3,200,000
Share-based compensation expense, capitalized					600,000	$ 1,200,000	1,100,000
Unrecognized compensation expenses					$ 1,500,000
Weighted average period over which options will be recognized					1 year 2 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period					3 year
Common shares issued for share based compensation | shares				156,415
Dividends Payable, Amount Per Share | $ / shares								$ 0.15
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 | shares					533,128	364,267
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | shares					231,388
Aggregate share-based awards awarded to executives | shares			231,388						186,395	61,720	134,284
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
Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense					$ 200,000	$ 100,000	100,000
Share purchases made by employees under ESPP					85% of the average closing price per share for a specified period
Maximum participant contribution, percentage of compensation					20.00%
Maximum participant contribution, dollar amount					$ 50,000
Aggregate share-based awards awarded to executives | shares					1,250,000
Stock Issued During Period, Value, Employee Stock Purchase Plan					$ 400,000	$ 500,000	$ 400,000
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date					15.00%

Share Based Compensation, 40106

Share Based Compensation, 401(k) Plan and Deferred Compensation - Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Option activity
Outstanding at beginning of year, shares	2,624,067
Exercised, shares	(111,209)
Forfeited/Expired, shares	(135,080)
Outstanding at end of year, shares	2,377,778	2,624,067
Vested/Exercisable at end of year, shares	2,377,778
Outstanding at beginning of year, Weighted Average Exercise Price	$ 15.47
Exercised, Weighted Average Exercise Price	11.56
Forfeited/Expired, Weighted Average Exercise Price	20.61
Outstanding at end of year, Weighted Average Exercise Price	15.36	$ 15.47
Vested/Exercisable at end of period, Weighted Average Exercise Price	$ 15.36
Weighted Average Remaining Contractual Term (in years)	2 years 1 month 24 days	3 years 1 month 13 days
Vested/Exercisable at end of period, Weighted Average Remaining Contractual Term (in years)	2 years 1 month 24 days
Exercised, Aggregated Intrinsic Value	$ 347,881
Outstanding at end of year, Aggregate Intrinsic Value	8,003,403
Vested/Exercisable at end of year, Aggregate Intrinsic Value	$ 8,003,403

Share Based Compensation, 40107

Share Based Compensation, 401(k) Plan and Deferred Compensation - Restricted Share Activity (Details) - Restricted Share Awards [Member]	12 Months Ended
	Dec. 31, 2016USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2016, shares | shares	506,147
Granted, shares | shares	227,845
Vested, shares | shares	(195,140)
Forfeited, shares | shares	(50,248)
Non-vested at December 31, 2016, shares | shares	488,604
Non-vested at January 1, 2016, Weighted Average Grant Date Fair Value | $ / shares	$ 14.50
Granted, Weighted Average Grant Date Fair Value | $ / shares	12.92
Vested, Weighted Average Grant Date Fair Value | $ / shares	13.50
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	15.03
Non-vested at December 31, 2016, Weighted Average Grant Date Fair Value | $ / shares	$ 14.10
Non-vested at January 1, 2016, Aggregate Intrinsic Value | $	$ 6,913,968
Granted, Aggregate Intrinsic Value | $	2,937,771
Vested, Aggregate Intrinsic Value | $	2,813,799
Non-vested at December 31, 2016, Aggregate Intrinsic Value | $	$ 8,066,852

Share Based Compensation, 40108

Share Based Compensation, 401(k) Plan and Deferred Compensation - Restricted Performance Share Units (Details) - Restricted Performance Share Units Plan [Member] - Executive Officer [Member] - USD ($) $ in Thousands	Feb. 22, 2016	Feb. 23, 2015	Mar. 12, 2014	Mar. 11, 2014	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2016, shares					364,267
Granted, shares					231,388
Units Cancelled					(62,527)
Non-vested at December 31, 2016, shares					533,128
Units Granted	231,388	186,395	61,720	134,284
Fair Value of Units on Grant Date (in thousands)	$ 3,558	$ 3,933	$ 1,255	$ 2,624
March 11, 2014 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2016, shares					123,155
Granted, shares					0
Units Cancelled					(30,724)
Non-vested at December 31, 2016, shares					92,431
Measurement Period Commencement Date					Jan. 1, 2014
Measurement Period End Date					Dec. 31, 2016
March 12, 2014 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2016, shares					61,720
Granted, shares					0
Units Cancelled					0
Non-vested at December 31, 2016, shares					61,720
Measurement Period Commencement Date					Jan. 1, 2014
Measurement Period End Date					Dec. 31, 2016
February 23, 2015 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2016, shares					179,392
Granted, shares					0
Units Cancelled					(31,803)
Non-vested at December 31, 2016, shares					147,589
Measurement Period Commencement Date					Jan. 1, 2015
Measurement Period End Date					Dec. 31, 2017
February 22, 2016 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2016, shares					0
Granted, shares					231,388
Units Cancelled					0
Non-vested at December 31, 2016, shares					231,388
Measurement Period Commencement Date					Jan. 1, 2016
Measurement Period End Date					Dec. 31, 2018

Distributions - Tax Characteris

Distributions - Tax Characteristics of Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Distributions [Abstract]
Common Share Distributions Payments of Ordinary Dividends	$ 0	$ 0.36	$ 0.41
Common Share Distributions Capital Gain	0.62	0.14	0.02
Common Share Distributions Non-taxable Distributions	0	0.10	0.17
Common Stock, Dividends, Per Share, Paid	$ 0.62	$ 0.60	$ 0.60
Percentage Of Distributions classified as ordinary income	0.00%	59.10%	69.00%
Percentage Of Distributions classified as capital gain	100.00%	23.50%	3.30%
Percentage Of Distributions classified as non-taxable distribution	0.00%	17.40%	27.70%
Dividends, Preferred Stock	$ 6,900	$ 6,900	$ 6,900
Percentage Of Preferred Distributions classified as ordinary income	100.00%	100.00%	100.00%

Tax Credit Transactions (Textua

Tax Credit Transactions (Textual) (Details) $ in Thousands	Dec. 30, 2008USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Aug. 27, 2010USD ($)	Nov. 17, 2008ft²
Tax Credit Carryforward [Line Items]
Tax credit transaction income			$ 0	$ (19,955)	$ (11,853)
Historic Tax Credit Transaction [Member]
Tax Credit Carryforward [Line Items]
Area Of IRS Campus Building | ft²							862,692
Percentage of building leased to IRS							100.00%
Purchase price for non-controlling interest obligation put option		$ 3,200
Rate of return on non-controlling interest		2.00%		2.00%
Percentage of tax credit recapture		20.00%
Tax credit transaction income		$ 11,900
Other income (expense)		(500)
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period			over the five year credit recapture period as defined in the Internal Revenue Code
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period in years			5 years
Accretion of non-controlling interest liability			$ 0	$ 1,100
Historic Tax Credit Transaction [Member] | Other Liabilities [Member]
Tax Credit Carryforward [Line Items]
Preferred return		$ 1,000
Historic Tax Credit Transaction [Member] | Other Assets [Member]
Tax Credit Carryforward [Line Items]
Deferred Costs			0	0
Historic Tax Credit Transaction [Member] | U S B [Member]
Tax Credit Carryforward [Line Items]
Agreed contribution in project cost						$ 64,100
USB contributions			$ 0	0
New Markets Tax Credit Transaction [Member]
Tax Credit Carryforward [Line Items]
Percentage of tax credit recapture			100.00%
Tax credit transaction income	$ 8,000			8,100
Recognition of cash received as revenue net of allocated expenses on or after September 2011, period in years			7 years
Percentage of qualified investments	39.00%
New Markets Tax Credit Transaction [Member] | Other Assets [Member]
Tax Credit Carryforward [Line Items]
Deferred Costs				$ 0
New Markets Tax Credit Transaction [Member] | U S B [Member]
Tax Credit Carryforward [Line Items]
USB contributions	$ 13,300

Accumulated Other Comprehens111

Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		$ (5,192)
Change during year		2,371	$ (1,010)	$ (1,190)
Settlement of interest rate swaps		0	0	(828)
Reclassification of realized losses on derivative financial instruments to operations, net	[1]	1,104	420	388
Balance at December 31,		(1,745)	(5,192)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		(5,597)
Change during year		2,371	(1,010)	(1,190)
Settlement of interest rate swaps		0	0	(828)
Reclassification of realized losses on derivative financial instruments to operations, net	[2]	1,104	420	388
Balance at December 31,		(2,122)	(5,597)
Accumulated Other Comprehensive Income (Loss) [Member]
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		(5,192)	(4,607)	(2,995)
Change during year		2,371	(1,010)	(1,190)
Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests		(28)	5	18
Settlement of interest rate swaps				(828)
Reclassification of realized losses on derivative financial instruments to operations, net		1,104	420	388
Balance at December 31,		(1,745)	(5,192)	(4,607)
Accumulated Other Comprehensive Income (Loss) [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		(5,597)	(5,007)	(3,377)
Change during year		2,371	(1,010)	(1,190)
Settlement of interest rate swaps				(828)
Reclassification of realized losses on derivative financial instruments to operations, net		1,104	420	388
Balance at December 31,		$ (2,122)	$ (5,597)	$ (5,007)
[1]	Amounts reclassified from comprehensive income to interest expense within the Consolidated Statements of Operations.
[2]	Amounts reclassified from comprehensive income to interest expense within the Consolidated Statement of Operations.

Accumulated Other Comprehens112

Accumulated Other Comprehensive Income (Loss) (Textual) (Details) $ in Millions	Dec. 31, 2016USD ($)
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Gains (losses) expected to be reclassified from AOCI into interest expense within the next twelve months	$ 1.2

Segment Information (Textual) (

Segment Information (Textual) (Details) - segment	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting [Abstract]
Number of Reportable Segments	5	7

Segment Information - Real Esta

Segment Information - Real Estate Investments, at Cost of Company's Reportable Segments (Details) - USD ($) $ in Thousands		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Segment Reporting Information [Line Items]
Operating properties		$ 3,586,295		$ 3,693,000		$ 4,603,692
Assets held for sale	[1],[2]	73,591	[3]	794,588	[3]	27,436
Operating Properties		3,659,886		4,487,588		4,631,128
Construction-in-progress		297,462		268,983		201,360
Land held for development		150,970		130,479		90,603
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Operating properties		1,320,974		1,157,667		1,338,655
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Operating properties		1,005,446		1,019,280		1,178,470
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Operating properties		975,987		1,129,206		1,183,652
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Operating properties		146,794		164,518		0
Other [Member]
Segment Reporting Information [Line Items]
Operating properties	[4]	$ 137,094		$ 222,329		$ 902,915
[1]	As of December 31, 2015, 2970 Market Street was classified as held for sale on the consolidated balance sheets. The property was sold on February 5, 2016. See Note 21, "Subsequent Events," for further information. The sale is not classified as a significant disposition under the accounting guidance for discontinued operations.
[2]	As of December 31, 2015, the 58 properties associated with the series of related transactions with Och-Ziff Real Estate were classified as held for sale on the consolidated balance sheets. On February 4, 2016, the Company completed a series of transactions, resulting in the disposition of the properties. See Note 3, “Real Estate Investments,” for further information regarding the disposition. Additionally, as of December 31, 2016, the Company categorized three office properties located in the Metropolitan Washington, D.C. segment and two properties in the Other segment as held for sale in accordance with applicable accounting standards for long lived assets. See Note 3, “Real Estate Investments,” for further information.
[3]	Real estate investments related to assets held for sale above represents gross real estate assets and does not include accumulated depreciation or other assets on the balance sheets of the properties held for sale. See Held for Sale section below.
[4]	As a result of the Och-Ziff Sale that occurred on February 4, 2016, the Company narrowed its segments to five segments: (1) Pennsylvania Suburbs, (2) Philadelphia Central Business District (“CBD”), (3) Metropolitan Washington, D.C. and (4) Austin, Texas and (5) Other. The Och-Ziff Sale disposed of the entire Richmond, Virginia segment. Subsequent to the Och-Ziff Sale, the segments previously defined as New Jersey/Delaware and California are now being managed as a consolidated segment entitled “Other,” as these geographies no longer provide a significant revenue contribution. Accordingly, the chief operating decision maker revised the management structure, reallocated resources, and is assessing business operations of the five segments as of January 1, 2016.

Segment Information - Real E115

Segment Information - Real Estate Investments, at Cost of Company's Reportable Segments (Parenthetical) (Details) - property	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Number of Properties	113
Office Properties [Member]
Segment Reporting Information [Line Items]
Number of Properties	93
Held for Sale Properties Included in Continuing Operations [Member]
Segment Reporting Information [Line Items]
Number of Properties	5
Cira Square [Member] | Held for Sale Properties Included in Continuing Operations [Member]
Segment Reporting Information [Line Items]
Number of Properties			58
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Number of Properties		2	3
Metropolitan DC [Member] | Held for Sale Properties Included in Continuing Operations [Member] | Office Properties [Member]
Segment Reporting Information [Line Items]
Number of Properties	3
Other [Member]
Segment Reporting Information [Line Items]
Number of Properties	3
Other [Member] | Held for Sale Properties Included in Continuing Operations [Member] | Office Properties [Member]
Segment Reporting Information [Line Items]
Number of Properties	2

Segment Information - Net Opera

Segment Information - Net Operating Income of Company's Reportable Segments (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total revenue		$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 525,463	$ 602,631	$ 596,982
Operating expenses	[1]									(209,448)	(238,087)	(235,965)
Net operating income										316,015	364,544	361,017
Operating Segments [Member] | Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Total revenue										200,245	209,298	201,809
Operating expenses	[1]									(78,708)	(77,352)	(75,262)
Net operating income										121,537	131,946	126,547
Operating Segments [Member] | Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Total revenue										144,338	158,398	160,630
Operating expenses	[1]									(49,208)	(57,319)	(55,062)
Net operating income										95,130	101,079	105,568
Operating Segments [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Total revenue										99,781	110,657	113,834
Operating expenses	[1]									(39,036)	(44,294)	(43,399)
Net operating income										60,745	66,363	70,435
Operating Segments [Member] | Austin, Texas [Member]
Segment Reporting Information [Line Items]
Total revenue	[2]									34,585	20,910	5,610
Operating expenses	[1],[2]									(13,222)	(8,010)	(3,223)
Net operating income	[2]									21,363	12,900	2,387
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Total revenue										39,359	98,799	113,971
Operating expenses	[1]									(23,204)	(49,604)	(57,214)
Net operating income										16,155	49,195	56,757
Corporate [Member]
Segment Reporting Information [Line Items]
Total revenue										7,155	4,569	1,128
Operating expenses	[1]									(6,070)	(1,508)	(1,805)
Net operating income										$ 1,085	$ 3,061	$ (677)
[1]	Includes property operating expense, real estate taxes and third party management expense.
[2]	On June 22, 2015 the Company acquired the remaining 50.0% of the common interest in Broadmoor Austin Associates. As such, the Company has seven wholly owned properties in its Austin, Texas business segment at December 31, 2016. In addition, net operating income for the years ended December 31, 2016 and 2015 includes management fees and related expenses for services provided by the Company to the Austin Venture. See Note 3, "Real Estate Investments," for further information regarding these transactions.

Segment Information - Net Op117

Segment Information - Net Operating Income of Company's Reportable Segments (Parenthetical) (Details) - property	Dec. 31, 2016	Jun. 22, 2015
Segment Reporting Information [Line Items]
Number of Properties	113
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Number of Properties	7
Broadmoor Austin Associates [Member]
Segment Reporting Information [Line Items]
Percentage of ownership interests		50.00%

Segment Information - Unconsoli

Segment Information - Unconsolidated Real Estate Ventures of Company's Reportable Segments (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		$ 281,331	$ 241,004	$ 225,004
Equity in loss of Real Estate Ventures		(11,503)	(811)	(790)
Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		48,691	44,089	27,137
Equity in loss of Real Estate Ventures		(686)	(188)	46
Pennsylvania Suburbs [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		15,421	16,408	17,385
Equity in loss of Real Estate Ventures		748	310	(777)
Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[1]	141,786	118,422	73,127
Equity in loss of Real Estate Ventures	[1]	(6,293)	(336)	(317)
MAP Venture [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[2]	20,893	0	0
Equity in loss of Real Estate Ventures	[2]	(4,218)	0	0
Other [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[3]	1,654	1,657	1,574
Equity in loss of Real Estate Ventures	[3]	814	930	1,338
Austin, Texas [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[4]	52,886	60,428	105,781
Equity in loss of Real Estate Ventures	[4]	$ (1,868)	$ (1,527)	$ (1,080)
[1]	On August 31, 2016, the Company terminated its lease for the regional management and leasing office at 3141 Fairview Park Drive, located in Falls Church, Virginia. Accordingly, the Company no longer has any continuing involvement with 3141 Fairview Park Drive and recorded the partial sale under the full accrual method of accounting. See Note 4, “Investment in Unconsolidated Real Estate Ventures,” for further information.
[2]	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. See Note 4 “Investment in Unconsolidated Real Estate Ventures,” for further information. 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.
[3]	See footnote (a) to the “Real estate investments, at cost” table above for further information regarding this segment.
[4]	Investment in real estate ventures does not include the $1.1 million negative investment balance in one real estate venture as of December 31, 2015, which is included in other liabilities. The Company disposed of its interest in this venture during the three-month period ended March 31, 2016. See Note 4, "Investment in Unconsolidated Real Estate Ventures," for further information. The decrease to the Company’s investment balance primarily relates to distributions from the G&I VII Austin Office LLC real estate venture.

Segment Information - Uncons119

Segment Information - Unconsolidated Real Estate Ventures of Company's Reportable Segments (Parenthetical) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Other liabilities	$ 19,408	$ 31,379
Coppell Associates [Member]
Segment Reporting Information [Line Items]
Other liabilities		$ 1,100

Segment Information - Reconcili

Segment Information - Reconciliation of Consolidated NOI to Consolidated Net Income (Loss) (Details) - USD ($) $ in Thousands	Jan. 14, 2016	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting [Abstract]
Consolidated net operating income										$ 316,015	$ 364,544	$ 361,017
Less:
Interest expense										(84,708)	(110,717)	(124,329)
Interest expense - amortization of deferred financing costs										(2,696)	(4,557)	(5,148)
Interest expense - financing obligation										(679)	(1,237)	(1,144)
Depreciation and amortization										(189,676)	(219,029)	(208,569)
General and administrative expenses										(26,596)	(29,406)	(26,779)
Equity in loss of real estate ventures										(11,503)	(811)	(790)
Provision for impairment				$ (1,800)						(40,517)	(82,208)	(1,765)
Plus:
Interest income										1,236	1,224	3,974
Tax credit transaction income										0	19,955	11,853
Recognized hedge activity										0	0	(828)
Net gain from remeasurement of investments in real estate ventures										0	758	458
Net gain on sales of interests in real estate										116,983	20,496	4,901
Net gain on sale of undepreciated real estate										9,232	3,019	1,184
Net gain (loss) on real estate venture transactions										20,000	7,229	(417)
Loss on early extinguishment of debt	$ (66,600)									(66,590)	0	(7,594)
Income (loss) from continuing operations										40,501	(30,740)	6,024
Income from discontinued operations										0	0	918
Net income (loss)		$ (12,370)	$ 7,884	$ (1,323)	$ 46,310	$ (62,700)	$ 20,308	$ 3,058	$ 8,594	$ 40,501	$ (30,740)	$ 6,942

Operating Leases - Minimum Futu

Operating Leases - Minimum Future Rentals on Non-cancelable Leases of Company properties leased to Tenants (Details) $ in Thousands	Dec. 31, 2016USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
2,017	$ 374,726
2,018	370,439
2,019	341,956
2,020	311,075
2,021	271,870
Thereafter	$ 1,292,599

Commitments and Contingencie122

Commitments and Contingencies (Textual) (Details)	Dec. 03, 2015ft²	Apr. 02, 2015USD ($)	Sep. 30, 2004USD ($)	Dec. 31, 2016USD ($)ft²a	Jan. 31, 2017	Jan. 30, 2017a	Jul. 01, 2016USD ($)a	Dec. 31, 2015USD ($)
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness to third parties				$ 997,466,000				$ 794,571,000
Agreed holding period (not to sell) for properties acquired as part of the TRC acquisition				15 years
Subaru Corporate Headquarters Project [Member]
Property Subject to or Available for Operating Lease [Line Items]
NTE Amount				$ 78,100,000
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
Project costs funded				10,500,000
Project costs				29,300,000
Subsequent Event [Member] | Garza Land Sale [Member]
Property Subject to or Available for Operating Lease [Line Items]
Area of land under agreement to sell | a						1.7
TB-BDN Plymouth Apartments [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount				3,200,000
Construction Loan				56,000,000
TB-BDN Plymouth Apartments [Member] | Subsequent Event [Member]
Property Subject to or Available for Operating Lease [Line Items]
Sale of ownership interest percentage					50.00%
1919 Venture [Member]
Property Subject to or Available for Operating Lease [Line Items]
Guarantees, maximum exposure amount				88,900,000
Unconsolidated Real Estate Ventures [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness to third parties				997,466,000
PJP VII [Member]
Property Subject to or Available for Operating Lease [Line Items]
Real estate ventures aggregate indebtedness to third parties				4,956,000				5,621,000
Guarantees, maximum exposure amount				400,000
618 Market Street [Member]
Property Subject to or Available for Operating Lease [Line Items]
Contingent consideration, liability		$ 2,000,000		$ 1,700,000
Fair value of contingent consideration		1,600,000
Interest expense		$ 2,000,000
Garza Land Acquisition [Member]
Property Subject to or Available for Operating Lease [Line Items]
Acreage of land | a							34.6
Area of land under agreement to sell | a				9.5
Infrastructure improvements to land, estimated cost							$ 10,300,000
Two Logan Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Leased Area Of Building | ft²				708,844
Amount to be paid if the Company takes fee title to Two Logan Square upon foreclosure of related mortgage				$ 2,900,000
Liability related to acquisition of TRC			$ 700,000	$ 2,200,000
Commerce Square [Member] | Prentiss Properties Trust [Member]
Property Subject to or Available for Operating Lease [Line Items]
Non-controlling interest, ownership percentage by non-controlling Owners				1.00%
One Commerce Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Tax guarantee obligation				$ 125,000,000
Two Commerce Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Tax guarantee obligation				100,000,000
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				4 years
Maximum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms				72 years
Mortgage Lenders [Member]
Property Subject to or Available for Operating Lease [Line Items]
Associated letter of credit				$ 10,000,000				$ 10,000,000

Commitments and Contingencies -

Commitments and Contingencies - Minimum Future Rental Payments on Non-cancelable Leases (Details) $ in Thousands	Dec. 31, 2016USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,017	$ 1,339
2,018	1,339
2,019	1,339
2,020	1,339
2,021	1,339
Thereafter	66,231
Total	$ 72,926

Subsequent Events (Textual) (De

Subsequent Events (Textual) (Details)	Feb. 02, 2017USD ($)ft²property	Jan. 31, 2017USD ($)property	Dec. 31, 2016USD ($)ft²property		Dec. 31, 2015USD ($)ft²property		Dec. 31, 2014USD ($)ft²property		Jan. 30, 2017USD ($)a	Jan. 10, 2017shares
Subsequent Event [Line Items]
Gain (Loss) on Sale			$ 116,983,000		$ 20,496,000		$ 4,901,000
Net gain (loss) on real estate venture transactions			$ 20,000,000		$ 7,229,000		$ (417,000)
Subsequent Event [Member]
Subsequent Event [Line Items]
Shares Authorized For Equity Offering Program | shares										16,000,000
TB-BDN Plymouth Apartments [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Gross sales price		$ 100,500,000
Sale of ownership interest percentage		50.00%
Guarantee obligations cancelled		$ 3,200,000
Equity in income (loss) of Real Estate Ventures		23,300,000
Net gain (loss) on real estate venture transactions		14,600,000
Cash proceeds after the payment of share of the debt and closing costs		27,200,000
TB-BDN Plymouth Apartments [Member] | Subsequent Event [Member] | Pennsylvania [Member]
Subsequent Event [Line Items]
Construction Loan		$ 54,000,000
TB-BDN Plymouth Apartments [Member] | Subsequent Event [Member] | Multi-Family Complex [Member]
Subsequent Event [Line Items]
Number of Property units | property		398
Garza Land Sale [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Area of land under agreement to sell | a									1.7
Sales price of properties sold									$ 3,500,000
Office Properties [Member]
Subsequent Event [Line Items]
Number of properties | property			66		27		8
Square feet of office space leased | ft²			5,239,632		2,649,926		645,273
Gross sales price			$ 820,000,000		$ 374,600,000		$ 101,150,000
Gain (Loss) on Sale			$ 116,983,000	[1]	$ 22,002,000	[2],[3]	$ 4,646,000	[4]
Office Properties [Member] | 1200 and 1220 Concord Avenue in Concord [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Number of properties | property	2
Square feet of office space leased | ft²	350,256
Gross sales price	$ 33,100,000
Gain (Loss) on Sale	500,000
Proceeds after closing costs and prorations	$ 32,000,000
[1]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[2]	Gain on Sale is net of closing and other transaction related costs.
[3]	Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale.
[4]	Gain/(Loss) on sale is net of closing and other transaction related costs.

Summary of Quarterly Results (D

Summary of Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Quarterly Financial Information [Line Items]
Total revenue	$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 525,463	$ 602,631	$ 596,982
Net income (loss)	(12,370)	7,884	(1,323)	46,310	(62,700)	20,308	3,058	8,594	40,501	(30,740)	6,942
Net income (loss) allocated to Common Shares/ Partnership Unitholders	$ (14,058)	$ 6,022	$ (3,105)	$ 44,091	$ (63,941)	$ 18,346	$ 1,255	$ 6,710	$ 40,191	$ (30,401)	$ 6,975
Basic earnings (loss) per Common Shares/Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ 0.19	$ (0.21)	$ 0
Diluted earnings (loss) per Common Share/ Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ 0.19	$ (0.21)	$ 0
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Quarterly Financial Information [Line Items]
Total revenue	$ 132,086	$ 129,694	$ 127,181	$ 136,502	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 525,463	$ 602,631	$ 596,982
Net income (loss)	(12,370)	7,884	(1,323)	46,310	(62,700)	20,308	3,058	8,594	40,501	(30,740)	6,942
Net income (loss) allocated to Common Shares/ Partnership Unitholders	$ (14,176)	$ 6,074	$ (3,131)	$ 44,478	$ (64,502)	$ 18,506	$ 1,262	$ 6,768	$ 40,486	$ (30,737)	$ 6,986
Basic earnings (loss) per Common Shares/Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.36)	$ 0.10	$ 0.04	$ 0.04	$ 0.19	$ (0.21)	$ 0
Diluted earnings (loss) per Common Share/ Partnership Unitholders	$ (0.08)	$ 0.03	$ (0.02)	$ 0.25	$ (0.36)	$ 0.10	$ 0.04	$ 0.04	$ 0.19	$ (0.21)	$ 0

Schedule II - Valuation and 126

Schedule II - Valuation and Qualifying Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance at Beginning of Period	$ 16,178	$ 15,347	$ 16,248
Valuation Allowances and Reserves, Additions	2,207	2,640	790
Valuation Allowances and Reserves, Deductions	2,269	1,809	1,691
Valuation Allowances and Reserves, Balance at End of Period	$ 16,116	$ 16,178	$ 15,347

Schedule III - Real Estate a127

Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 325,038
Initial Cost [Abstract]
Land	450,881
Buildings and Improvements	2,669,016
Net Improvements (Retirements) Since Acquisition	539,989
Carrying Amount at Which Carried [Abstract]
Land	481,282
Buildings and Improvements	3,178,604
Total	3,659,886	$ 4,487,588	$ 4,631,128	$ 4,669,289
Accumulated Depreciation at December 31, 2016	885,392	$ 1,080,616	$ 1,078,996	$ 983,808
PENNSYLVANIA SUBURBS [Member] | 400 Berwyn Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	0
Initial Cost [Abstract]
Land	2,657
Buildings and Improvements	4,462
Net Improvements (Retirements) Since Acquisition	13,383
Carrying Amount at Which Carried [Abstract]
Land	2,657
Buildings and Improvements	17,845
Total	20,502
Accumulated Depreciation at December 31, 2016	$ 7,132
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	1,999
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 300 Berwyn Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,206
Buildings and Improvements	13,422
Net Improvements (Retirements) Since Acquisition	4,014
Carrying Amount at Which Carried [Abstract]
Land	2,206
Buildings and Improvements	17,436
Total	19,642
Accumulated Depreciation at December 31, 2016	$ 9,213
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1050 Westlakes Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,611
Buildings and Improvements	10,445
Net Improvements (Retirements) Since Acquisition	6,130
Carrying Amount at Which Carried [Abstract]
Land	2,611
Buildings and Improvements	16,575
Total	19,186
Accumulated Depreciation at December 31, 2016	$ 9,450
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,999
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1200 Swedesford Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,595
Buildings and Improvements	11,809
Net Improvements (Retirements) Since Acquisition	2,996
Carrying Amount at Which Carried [Abstract]
Land	2,595
Buildings and Improvements	14,805
Total	17,400
Accumulated Depreciation at December 31, 2016	$ 8,043
Real Estate And Accumulated Depreciation Construction Year	1,994
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 200 Berwyn Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,533
Buildings and Improvements	9,460
Net Improvements (Retirements) Since Acquisition	1,864
Carrying Amount at Which Carried [Abstract]
Land	1,533
Buildings and Improvements	11,324
Total	12,857
Accumulated Depreciation at December 31, 2016	$ 5,947
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1180 Swedesford Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,086
Buildings and Improvements	8,342
Net Improvements (Retirements) Since Acquisition	3,110
Carrying Amount at Which Carried [Abstract]
Land	2,086
Buildings and Improvements	11,452
Total	13,538
Accumulated Depreciation at December 31, 2016	$ 4,429
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 100 Berwyn Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,180
Buildings and Improvements	7,290
Net Improvements (Retirements) Since Acquisition	1,483
Carrying Amount at Which Carried [Abstract]
Land	1,180
Buildings and Improvements	8,773
Total	9,953
Accumulated Depreciation at December 31, 2016	$ 4,508
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1160 Swedesford Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,781
Buildings and Improvements	7,124
Net Improvements (Retirements) Since Acquisition	6,108
Carrying Amount at Which Carried [Abstract]
Land	2,045
Buildings and Improvements	12,968
Total	15,013
Accumulated Depreciation at December 31, 2016	$ 4,437
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1100 Cassett Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,695
Buildings and Improvements	6,779
Net Improvements (Retirements) Since Acquisition	1,271
Carrying Amount at Which Carried [Abstract]
Land	1,695
Buildings and Improvements	8,050
Total	9,745
Accumulated Depreciation at December 31, 2016	$ 3,133
Real Estate And Accumulated Depreciation Construction Year	1,997
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | Six Tower Bridge (181 Washington Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,927
Buildings and Improvements	14,722
Net Improvements (Retirements) Since Acquisition	1,504
Carrying Amount at Which Carried [Abstract]
Land	6,237
Buildings and Improvements	16,916
Total	23,153
Accumulated Depreciation at December 31, 2016	$ 1,838
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,013
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 426 Lancaster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,689
Buildings and Improvements	6,756
Net Improvements (Retirements) Since Acquisition	376
Carrying Amount at Which Carried [Abstract]
Land	1,689
Buildings and Improvements	7,132
Total	8,821
Accumulated Depreciation at December 31, 2016	$ 3,812
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 52 Swedesford Square [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,241
Buildings and Improvements	16,579
Net Improvements (Retirements) Since Acquisition	3,852
Carrying Amount at Which Carried [Abstract]
Land	4,241
Buildings and Improvements	20,431
Total	24,672
Accumulated Depreciation at December 31, 2016	$ 8,834
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 640 Freedom Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,222
Buildings and Improvements	16,891
Net Improvements (Retirements) Since Acquisition	5,060
Carrying Amount at Which Carried [Abstract]
Land	4,222
Buildings and Improvements	21,951
Total	26,173
Accumulated Depreciation at December 31, 2016	$ 10,997
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 630 Allendale Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,836
Buildings and Improvements	4,028
Net Improvements (Retirements) Since Acquisition	12,614
Carrying Amount at Which Carried [Abstract]
Land	2,894
Buildings and Improvements	16,584
Total	19,478
Accumulated Depreciation at December 31, 2016	$ 6,597
Real Estate And Accumulated Depreciation Construction Year	2,000
Real Estate And Accumulated Depreciation Year Of Acquisition	2,000
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 620 Freedom Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,770
Buildings and Improvements	11,014
Net Improvements (Retirements) Since Acquisition	2,115
Carrying Amount at Which Carried [Abstract]
Land	2,770
Buildings and Improvements	13,129
Total	15,899
Accumulated Depreciation at December 31, 2016	$ 7,064
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1000 First Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,772
Buildings and Improvements	10,936
Net Improvements (Retirements) Since Acquisition	2,495
Carrying Amount at Which Carried [Abstract]
Land	2,772
Buildings and Improvements	13,431
Total	16,203
Accumulated Depreciation at December 31, 2016	$ 6,427
Real Estate And Accumulated Depreciation Construction Year	1,980
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1060 First Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,712
Buildings and Improvements	10,953
Net Improvements (Retirements) Since Acquisition	4,261
Carrying Amount at Which Carried [Abstract]
Land	2,712
Buildings and Improvements	15,214
Total	17,926
Accumulated Depreciation at December 31, 2016	$ 6,705
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 630 Freedom Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,773
Buildings and Improvements	11,144
Net Improvements (Retirements) Since Acquisition	3,786
Carrying Amount at Which Carried [Abstract]
Land	2,773
Buildings and Improvements	14,930
Total	17,703
Accumulated Depreciation at December 31, 2016	$ 7,019
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1020 First Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,168
Buildings and Improvements	8,576
Net Improvements (Retirements) Since Acquisition	7,627
Carrying Amount at Which Carried [Abstract]
Land	2,168
Buildings and Improvements	16,203
Total	18,371
Accumulated Depreciation at December 31, 2016	$ 8,469
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1040 First Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,860
Buildings and Improvements	11,282
Net Improvements (Retirements) Since Acquisition	5,037
Carrying Amount at Which Carried [Abstract]
Land	2,860
Buildings and Improvements	16,319
Total	19,179
Accumulated Depreciation at December 31, 2016	$ 6,699
Real Estate And Accumulated Depreciation Construction Year	1,985
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 610 Freedom Business Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,017
Buildings and Improvements	8,070
Net Improvements (Retirements) Since Acquisition	2,878
Carrying Amount at Which Carried [Abstract]
Land	2,017
Buildings and Improvements	10,948
Total	12,965
Accumulated Depreciation at December 31, 2016	$ 5,174
Real Estate And Accumulated Depreciation Construction Year	1,985
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 650 Park Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,916
Buildings and Improvements	4,378
Net Improvements (Retirements) Since Acquisition	1,561
Carrying Amount at Which Carried [Abstract]
Land	1,916
Buildings and Improvements	5,939
Total	7,855
Accumulated Depreciation at December 31, 2016	$ 3,295
Real Estate And Accumulated Depreciation Construction Year	1,968
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 600 Park Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,012
Buildings and Improvements	4,048
Net Improvements (Retirements) Since Acquisition	385
Carrying Amount at Which Carried [Abstract]
Land	1,012
Buildings and Improvements	4,433
Total	5,445
Accumulated Depreciation at December 31, 2016	$ 2,286
Real Estate And Accumulated Depreciation Construction Year	1,964
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 14 Campus Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,244
Buildings and Improvements	4,217
Net Improvements (Retirements) Since Acquisition	1,533
Carrying Amount at Which Carried [Abstract]
Land	2,244
Buildings and Improvements	5,750
Total	7,994
Accumulated Depreciation at December 31, 2016	$ 4,008
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 17 Campus Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,108
Buildings and Improvements	5,155
Net Improvements (Retirements) Since Acquisition	(924)
Carrying Amount at Which Carried [Abstract]
Land	1,108
Buildings and Improvements	4,231
Total	5,339
Accumulated Depreciation at December 31, 2016	$ 1,595
Real Estate And Accumulated Depreciation Construction Year	2,001
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 11 Campus Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,112
Buildings and Improvements	4,067
Net Improvements (Retirements) Since Acquisition	998
Carrying Amount at Which Carried [Abstract]
Land	1,112
Buildings and Improvements	5,065
Total	6,177
Accumulated Depreciation at December 31, 2016	$ 2,286
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	1,999
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 15 Campus Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,164
Buildings and Improvements	3,896
Net Improvements (Retirements) Since Acquisition	285
Carrying Amount at Which Carried [Abstract]
Land	1,164
Buildings and Improvements	4,181
Total	5,345
Accumulated Depreciation at December 31, 2016	$ 1,485
Real Estate And Accumulated Depreciation Construction Year	2,002
Real Estate And Accumulated Depreciation Year Of Acquisition	2,000
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 18 Campus Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	787
Buildings and Improvements	3,312
Net Improvements (Retirements) Since Acquisition	856
Carrying Amount at Which Carried [Abstract]
Land	787
Buildings and Improvements	4,168
Total	4,955
Accumulated Depreciation at December 31, 2016	$ 1,844
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 401 Plymouth Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,199
Buildings and Improvements	16,131
Net Improvements (Retirements) Since Acquisition	16,815
Carrying Amount at Which Carried [Abstract]
Land	6,199
Buildings and Improvements	32,946
Total	39,145
Accumulated Depreciation at December 31, 2016	$ 12,591
Real Estate And Accumulated Depreciation Construction Year	2,001
Real Estate And Accumulated Depreciation Year Of Acquisition	2,000
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | Metroplex (4000 Chemical Road) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,373
Buildings and Improvements	24,546
Net Improvements (Retirements) Since Acquisition	1,300
Carrying Amount at Which Carried [Abstract]
Land	4,373
Buildings and Improvements	25,846
Total	30,219
Accumulated Depreciation at December 31, 2016	$ 6,243
Real Estate And Accumulated Depreciation Construction Year	2,007
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 610 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,651
Buildings and Improvements	14,514
Net Improvements (Retirements) Since Acquisition	3,337
Carrying Amount at Which Carried [Abstract]
Land	3,651
Buildings and Improvements	17,851
Total	21,502
Accumulated Depreciation at December 31, 2016	$ 6,986
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,002
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 600 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,652
Buildings and Improvements	15,288
Net Improvements (Retirements) Since Acquisition	2,295
Carrying Amount at Which Carried [Abstract]
Land	3,652
Buildings and Improvements	17,583
Total	21,235
Accumulated Depreciation at December 31, 2016	$ 6,436
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	2,002
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 630 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,558
Buildings and Improvements	14,743
Net Improvements (Retirements) Since Acquisition	1,630
Carrying Amount at Which Carried [Abstract]
Land	3,558
Buildings and Improvements	16,373
Total	19,931
Accumulated Depreciation at December 31, 2016	$ 6,002
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,002
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 620 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,572
Buildings and Improvements	14,435
Net Improvements (Retirements) Since Acquisition	1,119
Carrying Amount at Which Carried [Abstract]
Land	3,572
Buildings and Improvements	15,554
Total	19,126
Accumulated Depreciation at December 31, 2016	$ 5,778
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	2,002
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 660 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,694
Buildings and Improvements	5,487
Net Improvements (Retirements) Since Acquisition	19,487
Carrying Amount at Which Carried [Abstract]
Land	5,405
Buildings and Improvements	23,263
Total	28,668
Accumulated Depreciation at December 31, 2016	$ 3,359
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,012
Depreciable Life (Years)	30 years
PENNSYLVANIA SUBURBS [Member] | 351 Plymouth Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,043
Buildings and Improvements	555
Net Improvements (Retirements) Since Acquisition	0
Carrying Amount at Which Carried [Abstract]
Land	1,043
Buildings and Improvements	555
Total	1,598
Accumulated Depreciation at December 31, 2016	$ 163
Real Estate And Accumulated Depreciation Year Of Acquisition	2,000
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 150 Radnor Chester Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	11,925
Buildings and Improvements	36,986
Net Improvements (Retirements) Since Acquisition	11,990
Carrying Amount at Which Carried [Abstract]
Land	11,897
Buildings and Improvements	49,004
Total	60,901
Accumulated Depreciation at December 31, 2016	$ 20,032
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	29 years
PENNSYLVANIA SUBURBS [Member] | One Radnor Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,323
Buildings and Improvements	28,613
Net Improvements (Retirements) Since Acquisition	23,052
Carrying Amount at Which Carried [Abstract]
Land	7,323
Buildings and Improvements	51,665
Total	58,988
Accumulated Depreciation at December 31, 2016	$ 23,923
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	29 years
PENNSYLVANIA SUBURBS [Member] | 201 King of Prussia Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	8,956
Buildings and Improvements	29,811
Net Improvements (Retirements) Since Acquisition	4,587
Carrying Amount at Which Carried [Abstract]
Land	8,949
Buildings and Improvements	34,405
Total	43,354
Accumulated Depreciation at December 31, 2016	$ 17,840
Real Estate And Accumulated Depreciation Construction Year	2,001
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	25 years
PENNSYLVANIA SUBURBS [Member] | 555 Lancaster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	8,014
Buildings and Improvements	16,508
Net Improvements (Retirements) Since Acquisition	17,847
Carrying Amount at Which Carried [Abstract]
Land	8,609
Buildings and Improvements	33,760
Total	42,369
Accumulated Depreciation at December 31, 2016	$ 15,559
Real Estate And Accumulated Depreciation Construction Year	1,973
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	24 years
PENNSYLVANIA SUBURBS [Member] | Four Radnor Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	5,406
Buildings and Improvements	21,390
Net Improvements (Retirements) Since Acquisition	13,271
Carrying Amount at Which Carried [Abstract]
Land	5,705
Buildings and Improvements	34,362
Total	40,067
Accumulated Depreciation at December 31, 2016	$ 12,531
Real Estate And Accumulated Depreciation Construction Year	1,995
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	30 years
PENNSYLVANIA SUBURBS [Member] | Five Radnor Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,506
Buildings and Improvements	25,525
Net Improvements (Retirements) Since Acquisition	5,540
Carrying Amount at Which Carried [Abstract]
Land	6,578
Buildings and Improvements	30,993
Total	37,571
Accumulated Depreciation at December 31, 2016	$ 10,392
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	38 years
PENNSYLVANIA SUBURBS [Member] | Three Radnor Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,773
Buildings and Improvements	17,961
Net Improvements (Retirements) Since Acquisition	2,615
Carrying Amount at Which Carried [Abstract]
Land	4,791
Buildings and Improvements	20,558
Total	25,349
Accumulated Depreciation at December 31, 2016	$ 9,654
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	29 years
PENNSYLVANIA SUBURBS [Member] | Two Radnor Corporate Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,937
Buildings and Improvements	15,484
Net Improvements (Retirements) Since Acquisition	4,075
Carrying Amount at Which Carried [Abstract]
Land	3,942
Buildings and Improvements	19,554
Total	23,496
Accumulated Depreciation at December 31, 2016	$ 8,510
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	29 years
PENNSYLVANIA SUBURBS [Member] | 130 Radnor Chester Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,573
Buildings and Improvements	8,338
Net Improvements (Retirements) Since Acquisition	3,483
Carrying Amount at Which Carried [Abstract]
Land	2,567
Buildings and Improvements	11,827
Total	14,394
Accumulated Depreciation at December 31, 2016	$ 5,433
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	25 years
PENNSYLVANIA SUBURBS [Member] | 170 Radnor Chester Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,514
Buildings and Improvements	8,147
Net Improvements (Retirements) Since Acquisition	2,864
Carrying Amount at Which Carried [Abstract]
Land	2,509
Buildings and Improvements	11,016
Total	13,525
Accumulated Depreciation at December 31, 2016	$ 3,992
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	25 years
PENNSYLVANIA SUBURBS [Member] | 200 N. Radnor Chester Rd. [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,366
Buildings and Improvements	0
Net Improvements (Retirements) Since Acquisition	3,583
Carrying Amount at Which Carried [Abstract]
Land	3,366
Buildings and Improvements	3,583
Total	6,949
Accumulated Depreciation at December 31, 2016	$ 373
Real Estate And Accumulated Depreciation Construction Year	2,014
Real Estate And Accumulated Depreciation Year Of Acquisition	2,005
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 101 West Elm Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,251
Buildings and Improvements	25,209
Net Improvements (Retirements) Since Acquisition	3,170
Carrying Amount at Which Carried [Abstract]
Land	6,251
Buildings and Improvements	28,379
Total	34,630
Accumulated Depreciation at December 31, 2016	$ 8,912
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,005
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 1 West Elm Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,557
Buildings and Improvements	14,249
Net Improvements (Retirements) Since Acquisition	3,125
Carrying Amount at Which Carried [Abstract]
Land	3,557
Buildings and Improvements	17,374
Total	20,931
Accumulated Depreciation at December 31, 2016	$ 4,687
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,005
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | Cira Centre (2929 Arch Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	208,570
Net Improvements (Retirements) Since Acquisition	(9,473)
Carrying Amount at Which Carried [Abstract]
Land	12,586
Buildings and Improvements	186,511
Total	199,097
Accumulated Depreciation at December 31, 2016	$ 63,153
Real Estate And Accumulated Depreciation Construction Year	2,005
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | Three Logan Square (1717 Arch Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	98,188
Net Improvements (Retirements) Since Acquisition	68,691
Carrying Amount at Which Carried [Abstract]
Land	25,195
Buildings and Improvements	141,684
Total	166,879
Accumulated Depreciation at December 31, 2016	$ 33,059
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	2,010
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | Two Commerce Square (2001 Market Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 112,000
Initial Cost [Abstract]
Land	15,323
Buildings and Improvements	120,200
Net Improvements (Retirements) Since Acquisition	21,518
Carrying Amount at Which Carried [Abstract]
Land	15,323
Buildings and Improvements	141,718
Total	157,041
Accumulated Depreciation at December 31, 2016	$ 12,190
Real Estate And Accumulated Depreciation Construction Year	1,992
Real Estate And Accumulated Depreciation Year Of Acquisition	2,013
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | One Logan Square (130 North 18th Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	14,496
Buildings and Improvements	107,736
Net Improvements (Retirements) Since Acquisition	27,447
Carrying Amount at Which Carried [Abstract]
Land	14,473
Buildings and Improvements	135,206
Total	149,679
Accumulated Depreciation at December 31, 2016	$ 46,840
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	34 years
Philadelphia CBD [Member] | Two Logan Square (100 North 18th Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 86,012
Initial Cost [Abstract]
Land	16,066
Buildings and Improvements	100,255
Net Improvements (Retirements) Since Acquisition	17,631
Carrying Amount at Which Carried [Abstract]
Land	16,066
Buildings and Improvements	117,886
Total	133,952
Accumulated Depreciation at December 31, 2016	$ 37,378
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	36 years
Philadelphia CBD [Member] | One Commerce Square (2005 Market Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 127,026
Initial Cost [Abstract]
Land	15,161
Buildings and Improvements	105,021
Net Improvements (Retirements) Since Acquisition	21,419
Carrying Amount at Which Carried [Abstract]
Land	15,160
Buildings and Improvements	126,441
Total	141,601
Accumulated Depreciation at December 31, 2016	$ 11,190
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,013
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | Cira Centre South Garage [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	76,008
Net Improvements (Retirements) Since Acquisition	7,588
Carrying Amount at Which Carried [Abstract]
Land	0
Buildings and Improvements	83,596
Total	83,596
Accumulated Depreciation at December 31, 2016	$ 12,504
Real Estate And Accumulated Depreciation Construction Year	2,010
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | 1900 Market [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,768
Buildings and Improvements	17,263
Net Improvements (Retirements) Since Acquisition	27,176
Carrying Amount at Which Carried [Abstract]
Land	7,768
Buildings and Improvements	44,439
Total	52,207
Accumulated Depreciation at December 31, 2016	$ 4,389
Real Estate And Accumulated Depreciation Construction Year	1,981
Real Estate And Accumulated Depreciation Year Of Acquisition	2,012
Depreciable Life (Years)	30 years
Philadelphia CBD [Member] | 3020 Market Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	21,417
Net Improvements (Retirements) Since Acquisition	7,651
Carrying Amount at Which Carried [Abstract]
Land	0
Buildings and Improvements	29,068
Total	29,068
Accumulated Depreciation at December 31, 2016	$ 6,105
Real Estate And Accumulated Depreciation Construction Year	1,959
Real Estate And Accumulated Depreciation Year Of Acquisition	2,011
Depreciable Life (Years)	26 years
Philadelphia CBD [Member] | The Lift at Juniper Street (101 - 103 Juniper Street) [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	14,401
Net Improvements (Retirements) Since Acquisition	324
Carrying Amount at Which Carried [Abstract]
Land	478
Buildings and Improvements	14,247
Total	14,725
Accumulated Depreciation at December 31, 2016	$ 2,915
Real Estate And Accumulated Depreciation Construction Year	2,010
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | Philadelphia Marine Center [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	532
Buildings and Improvements	2,196
Net Improvements (Retirements) Since Acquisition	4,317
Carrying Amount at Which Carried [Abstract]
Land	628
Buildings and Improvements	6,417
Total	7,045
Accumulated Depreciation at December 31, 2016	$ 2,965
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | 618-634 Market Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	13,365
Buildings and Improvements	5,791
Net Improvements (Retirements) Since Acquisition	460
Carrying Amount at Which Carried [Abstract]
Land	13,365
Buildings and Improvements	6,251
Total	19,616
Accumulated Depreciation at December 31, 2016	$ 2,056
Real Estate And Accumulated Depreciation Construction Year	1,966
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	5 years
Philadelphia CBD [Member] | FMC Tower at Cira Centre South [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	166,474
Net Improvements (Retirements) Since Acquisition	0
Carrying Amount at Which Carried [Abstract]
Land	0
Buildings and Improvements	166,474
Total	166,474
Accumulated Depreciation at December 31, 2016	$ 3,325
Real Estate And Accumulated Depreciation Construction Year	2,016
Depreciable Life (Years)	40 years
Metropolitan DC [Member] | 11720 Beltsville Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,831
Buildings and Improvements	16,661
Net Improvements (Retirements) Since Acquisition	(8,065)
Carrying Amount at Which Carried [Abstract]
Land	1,472
Buildings and Improvements	10,955
Total	12,427
Accumulated Depreciation at December 31, 2016	$ 6,066
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	46 years
Metropolitan DC [Member] | 11700 Beltsville Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,808
Buildings and Improvements	12,081
Net Improvements (Retirements) Since Acquisition	(10,823)
Carrying Amount at Which Carried [Abstract]
Land	257
Buildings and Improvements	3,809
Total	4,066
Accumulated Depreciation at December 31, 2016	$ 2,999
Real Estate And Accumulated Depreciation Construction Year	1,981
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	46 years
Metropolitan DC [Member] | 11710 Beltsville Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,278
Buildings and Improvements	11,100
Net Improvements (Retirements) Since Acquisition	(9,060)
Carrying Amount at Which Carried [Abstract]
Land	408
Buildings and Improvements	3,910
Total	4,318
Accumulated Depreciation at December 31, 2016	$ 2,615
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	46 years
Metropolitan DC [Member] | 11740 Beltsville Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	198
Buildings and Improvements	870
Net Improvements (Retirements) Since Acquisition	(159)
Carrying Amount at Which Carried [Abstract]
Land	155
Buildings and Improvements	754
Total	909
Accumulated Depreciation at December 31, 2016	$ 255
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	46 years
Metropolitan DC [Member] | 6600 Rockledge Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	37,421
Net Improvements (Retirements) Since Acquisition	10,700
Carrying Amount at Which Carried [Abstract]
Land	0
Buildings and Improvements	48,121
Total	48,121
Accumulated Depreciation at December 31, 2016	$ 11,894
Real Estate And Accumulated Depreciation Construction Year	1,981
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	50 years
Metropolitan DC [Member] | 2340 Dulles Corner Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	16,345
Buildings and Improvements	65,379
Net Improvements (Retirements) Since Acquisition	5,188
Carrying Amount at Which Carried [Abstract]
Land	16,129
Buildings and Improvements	70,783
Total	86,912
Accumulated Depreciation at December 31, 2016	$ 21,568
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	40 years
Metropolitan DC [Member] | 2291 Wood Oak Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	8,243
Buildings and Improvements	52,413
Net Improvements (Retirements) Since Acquisition	12,543
Carrying Amount at Which Carried [Abstract]
Land	8,782
Buildings and Improvements	64,417
Total	73,199
Accumulated Depreciation at December 31, 2016	$ 17,417
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	55 years
Metropolitan DC [Member] | 2251 Corporate Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	11,472
Buildings and Improvements	45,893
Net Improvements (Retirements) Since Acquisition	3,411
Carrying Amount at Which Carried [Abstract]
Land	11,472
Buildings and Improvements	49,304
Total	60,776
Accumulated Depreciation at December 31, 2016	$ 12,696
Real Estate And Accumulated Depreciation Construction Year	2,000
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	40 years
Metropolitan DC [Member] | 2355 Dulles Corner Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	10,365
Buildings and Improvements	43,876
Net Improvements (Retirements) Since Acquisition	4,510
Carrying Amount at Which Carried [Abstract]
Land	10,365
Buildings and Improvements	48,386
Total	58,751
Accumulated Depreciation at December 31, 2016	$ 15,120
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	40 years
Metropolitan DC [Member] | 2411 Dulles Corner Park [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,279
Buildings and Improvements	46,340
Net Improvements (Retirements) Since Acquisition	18,759
Carrying Amount at Which Carried [Abstract]
Land	7,417
Buildings and Improvements	64,961
Total	72,378
Accumulated Depreciation at December 31, 2016	$ 13,783
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	50 years
Metropolitan DC [Member] | 13880 Dulles Corner Lane [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,236
Buildings and Improvements	39,213
Net Improvements (Retirements) Since Acquisition	4,458
Carrying Amount at Which Carried [Abstract]
Land	7,373
Buildings and Improvements	43,534
Total	50,907
Accumulated Depreciation at December 31, 2016	$ 10,044
Real Estate And Accumulated Depreciation Construction Year	1,997
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	55 years
Metropolitan DC [Member] | 2121 Cooperative Way [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	5,598
Buildings and Improvements	38,639
Net Improvements (Retirements) Since Acquisition	2,793
Carrying Amount at Which Carried [Abstract]
Land	5,795
Buildings and Improvements	41,235
Total	47,030
Accumulated Depreciation at December 31, 2016	$ 9,814
Real Estate And Accumulated Depreciation Construction Year	2,000
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	54 years
Metropolitan DC [Member] | 2201 Cooperative Way [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,809
Buildings and Improvements	34,093
Net Improvements (Retirements) Since Acquisition	6,051
Carrying Amount at Which Carried [Abstract]
Land	4,809
Buildings and Improvements	40,144
Total	44,953
Accumulated Depreciation at December 31, 2016	$ 9,918
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	54 years
Metropolitan DC [Member] | 13825 Sunrise Valley Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,794
Buildings and Improvements	19,365
Net Improvements (Retirements) Since Acquisition	2,485
Carrying Amount at Which Carried [Abstract]
Land	3,866
Buildings and Improvements	21,778
Total	25,644
Accumulated Depreciation at December 31, 2016	$ 6,283
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	46 years
Metropolitan DC [Member] | 1676 International Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	18,437
Buildings and Improvements	97,538
Net Improvements (Retirements) Since Acquisition	3,307
Carrying Amount at Which Carried [Abstract]
Land	18,785
Buildings and Improvements	100,497
Total	119,282
Accumulated Depreciation at December 31, 2016	$ 21,039
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	55 years
Metropolitan DC [Member] | 8260 Greensboro Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,952
Buildings and Improvements	33,964
Net Improvements (Retirements) Since Acquisition	2,873
Carrying Amount at Which Carried [Abstract]
Land	8,102
Buildings and Improvements	36,687
Total	44,789
Accumulated Depreciation at December 31, 2016	$ 9,000
Real Estate And Accumulated Depreciation Construction Year	1,980
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	52 years
Metropolitan DC [Member] | 2273 Research Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	5,167
Buildings and Improvements	31,110
Net Improvements (Retirements) Since Acquisition	4,153
Carrying Amount at Which Carried [Abstract]
Land	5,237
Buildings and Improvements	35,193
Total	40,430
Accumulated Depreciation at December 31, 2016	$ 8,885
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	45 years
Metropolitan DC [Member] | 2275 Research Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	5,059
Buildings and Improvements	29,668
Net Improvements (Retirements) Since Acquisition	8,227
Carrying Amount at Which Carried [Abstract]
Land	5,154
Buildings and Improvements	37,800
Total	42,954
Accumulated Depreciation at December 31, 2016	$ 10,439
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	45 years
Metropolitan DC [Member] | 2277 Research Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,649
Buildings and Improvements	26,952
Net Improvements (Retirements) Since Acquisition	18,863
Carrying Amount at Which Carried [Abstract]
Land	4,733
Buildings and Improvements	45,731
Total	50,464
Accumulated Depreciation at December 31, 2016	$ 10,051
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	45 years
Metropolitan DC [Member] | 1900 Gallows Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,797
Buildings and Improvements	47,817
Net Improvements (Retirements) Since Acquisition	12,386
Carrying Amount at Which Carried [Abstract]
Land	7,944
Buildings and Improvements	60,056
Total	68,000
Accumulated Depreciation at December 31, 2016	$ 15,234
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	52 years
Metropolitan DC [Member] | 8521 Leesburg Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,316
Buildings and Improvements	30,885
Net Improvements (Retirements) Since Acquisition	6,201
Carrying Amount at Which Carried [Abstract]
Land	4,397
Buildings and Improvements	37,005
Total	41,402
Accumulated Depreciation at December 31, 2016	$ 8,321
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	51 years
Austin, Texas [Member] | 11501 Burnet Road - Building 1 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,755
Buildings and Improvements	22,702
Net Improvements (Retirements) Since Acquisition	144
Carrying Amount at Which Carried [Abstract]
Land	3,755
Buildings and Improvements	22,846
Total	26,601
Accumulated Depreciation at December 31, 2016	$ 1,071
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Austin, Texas [Member] | 11501 Burnet Road - Building 2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,732
Buildings and Improvements	16,305
Net Improvements (Retirements) Since Acquisition	1,518
Carrying Amount at Which Carried [Abstract]
Land	2,732
Buildings and Improvements	17,823
Total	20,555
Accumulated Depreciation at December 31, 2016	$ 936
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Austin, Texas [Member] | 11501 Burnet Road - Building 3 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,688
Buildings and Improvements	22,348
Net Improvements (Retirements) Since Acquisition	142
Carrying Amount at Which Carried [Abstract]
Land	3,688
Buildings and Improvements	22,490
Total	26,178
Accumulated Depreciation at December 31, 2016	$ 1,055
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Austin, Texas [Member] | 11501 Burnet Road - Building 4 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,614
Buildings and Improvements	15,740
Net Improvements (Retirements) Since Acquisition	100
Carrying Amount at Which Carried [Abstract]
Land	2,614
Buildings and Improvements	15,840
Total	18,454
Accumulated Depreciation at December 31, 2016	$ 743
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Austin, Texas [Member] | 11501 Burnet Road - Building 5 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,689
Buildings and Improvements	22,354
Net Improvements (Retirements) Since Acquisition	142
Carrying Amount at Which Carried [Abstract]
Land	3,689
Buildings and Improvements	22,496
Total	26,185
Accumulated Depreciation at December 31, 2016	$ 1,055
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Austin, Texas [Member] | 11501 Burnet Road - Building 8 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,400
Buildings and Improvements	7,422
Net Improvements (Retirements) Since Acquisition	47
Carrying Amount at Which Carried [Abstract]
Land	1,400
Buildings and Improvements	7,469
Total	8,869
Accumulated Depreciation at December 31, 2016	$ 357
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Austin, Texas [Member] | 11501 Burnet Road - Parking Garage [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	0
Buildings and Improvements	19,826
Net Improvements (Retirements) Since Acquisition	126
Carrying Amount at Which Carried [Abstract]
Land	0
Buildings and Improvements	19,952
Total	19,952
Accumulated Depreciation at December 31, 2016	$ 1,248
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Other [Member] | 200 Lake Drive East [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,069
Buildings and Improvements	8,275
Net Improvements (Retirements) Since Acquisition	(844)
Carrying Amount at Which Carried [Abstract]
Land	1,440
Buildings and Improvements	8,060
Total	9,500
Accumulated Depreciation at December 31, 2016	$ 3,995
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
Other [Member] | 220 Lake Drive East [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,144
Buildings and Improvements	8,798
Net Improvements (Retirements) Since Acquisition	(713)
Carrying Amount at Which Carried [Abstract]
Land	1,492
Buildings and Improvements	8,737
Total	10,229
Accumulated Depreciation at December 31, 2016	$ 4,093
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
Other [Member] | 210 Lake Drive East [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,645
Buildings and Improvements	6,579
Net Improvements (Retirements) Since Acquisition	564
Carrying Amount at Which Carried [Abstract]
Land	1,145
Buildings and Improvements	7,643
Total	8,788
Accumulated Depreciation at December 31, 2016	$ 3,618
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
Other [Member] | 1200 Concord Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,395
Buildings and Improvements	24,664
Net Improvements (Retirements) Since Acquisition	(5,168)
Carrying Amount at Which Carried [Abstract]
Land	4,748
Buildings and Improvements	21,143
Total	25,891
Accumulated Depreciation at December 31, 2016	$ 10,481
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	34 years
Other [Member] | 1220 Concord Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,476
Buildings and Improvements	24,966
Net Improvements (Retirements) Since Acquisition	(5,463)
Carrying Amount at Which Carried [Abstract]
Land	4,719
Buildings and Improvements	21,260
Total	25,979
Accumulated Depreciation at December 31, 2016	$ 10,500
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	34 years
Other [Member] | 20 East Clementon Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	769
Buildings and Improvements	3,055
Net Improvements (Retirements) Since Acquisition	500
Carrying Amount at Which Carried [Abstract]
Land	719
Buildings and Improvements	3,605
Total	4,324
Accumulated Depreciation at December 31, 2016	$ 1,815
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 10 Foster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	244
Buildings and Improvements	971
Net Improvements (Retirements) Since Acquisition	69
Carrying Amount at Which Carried [Abstract]
Land	244
Buildings and Improvements	1,040
Total	1,284
Accumulated Depreciation at December 31, 2016	$ 544
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 7 Foster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	231
Buildings and Improvements	921
Net Improvements (Retirements) Since Acquisition	75
Carrying Amount at Which Carried [Abstract]
Land	231
Buildings and Improvements	996
Total	1,227
Accumulated Depreciation at December 31, 2016	$ 520
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 2 Foster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	185
Buildings and Improvements	730
Net Improvements (Retirements) Since Acquisition	58
Carrying Amount at Which Carried [Abstract]
Land	185
Buildings and Improvements	788
Total	973
Accumulated Depreciation at December 31, 2016	$ 382
Real Estate And Accumulated Depreciation Construction Year	1,974
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 4 Foster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	183
Buildings and Improvements	726
Net Improvements (Retirements) Since Acquisition	30
Carrying Amount at Which Carried [Abstract]
Land	183
Buildings and Improvements	756
Total	939
Accumulated Depreciation at December 31, 2016	$ 376
Real Estate And Accumulated Depreciation Construction Year	1,974
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 1 Foster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	93
Buildings and Improvements	364
Net Improvements (Retirements) Since Acquisition	30
Carrying Amount at Which Carried [Abstract]
Land	93
Buildings and Improvements	394
Total	487
Accumulated Depreciation at December 31, 2016	$ 212
Real Estate And Accumulated Depreciation Construction Year	1,972
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 5 U.S. Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	21
Buildings and Improvements	81
Net Improvements (Retirements) Since Acquisition	2
Carrying Amount at Which Carried [Abstract]
Land	21
Buildings and Improvements	83
Total	104
Accumulated Depreciation at December 31, 2016	$ 43
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 5 Foster Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	9
Buildings and Improvements	32
Net Improvements (Retirements) Since Acquisition	26
Carrying Amount at Which Carried [Abstract]
Land	9
Buildings and Improvements	58
Total	67
Accumulated Depreciation at December 31, 2016	$ 32
Real Estate And Accumulated Depreciation Construction Year	1,968
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | Two Eves Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	818
Buildings and Improvements	3,461
Net Improvements (Retirements) Since Acquisition	269
Carrying Amount at Which Carried [Abstract]
Land	818
Buildings and Improvements	3,730
Total	4,548
Accumulated Depreciation at December 31, 2016	$ 1,897
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | Five Eves Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	703
Buildings and Improvements	2,819
Net Improvements (Retirements) Since Acquisition	1,456
Carrying Amount at Which Carried [Abstract]
Land	703
Buildings and Improvements	4,275
Total	4,978
Accumulated Depreciation at December 31, 2016	$ 1,996
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | Four B Eves Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	588
Buildings and Improvements	2,369
Net Improvements (Retirements) Since Acquisition	185
Carrying Amount at Which Carried [Abstract]
Land	588
Buildings and Improvements	2,554
Total	3,142
Accumulated Depreciation at December 31, 2016	$ 1,377
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | Four A Eves Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	539
Buildings and Improvements	2,168
Net Improvements (Retirements) Since Acquisition	608
Carrying Amount at Which Carried [Abstract]
Land	539
Buildings and Improvements	2,776
Total	3,315
Accumulated Depreciation at December 31, 2016	$ 1,305
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 7000 Midlantic Derive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,560
Buildings and Improvements	2,790
Net Improvements (Retirements) Since Acquisition	0
Carrying Amount at Which Carried [Abstract]
Land	2,560
Buildings and Improvements	2,790
Total	5,350
Accumulated Depreciation at December 31, 2016	$ 51
Real Estate And Accumulated Depreciation Construction Year	2,016
Real Estate And Accumulated Depreciation Year Of Acquisition	2,003
Depreciable Life (Years)	40 years
Other [Member] | Main Street-Plaza 1000 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,732
Buildings and Improvements	10,942
Net Improvements (Retirements) Since Acquisition	95
Carrying Amount at Which Carried [Abstract]
Land	2,732
Buildings and Improvements	11,037
Total	13,769
Accumulated Depreciation at December 31, 2016	$ 11,012
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | Main Street-Piazza [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	696
Buildings and Improvements	2,802
Net Improvements (Retirements) Since Acquisition	3,442
Carrying Amount at Which Carried [Abstract]
Land	696
Buildings and Improvements	6,244
Total	6,940
Accumulated Depreciation at December 31, 2016	$ 2,375
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | Main Street-Promenade [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	532
Buildings and Improvements	2,052
Net Improvements (Retirements) Since Acquisition	525
Carrying Amount at Which Carried [Abstract]
Land	532
Buildings and Improvements	2,577
Total	3,109
Accumulated Depreciation at December 31, 2016	$ 1,379
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
Other [Member] | 920 North King Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,141
Buildings and Improvements	21,140
Net Improvements (Retirements) Since Acquisition	3,599
Carrying Amount at Which Carried [Abstract]
Land	6,141
Buildings and Improvements	24,739
Total	30,880
Accumulated Depreciation at December 31, 2016	$ 9,090
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	30 years
Other [Member] | 300 Delaware Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	6,369
Buildings and Improvements	13,739
Net Improvements (Retirements) Since Acquisition	3,032
Carrying Amount at Which Carried [Abstract]
Land	6,369
Buildings and Improvements	16,771
Total	23,140
Accumulated Depreciation at December 31, 2016	$ 8,202
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	23 years

Schedule III - Real Estate a128

Schedule III - Real Estate and Accumulated Depreciation (Reconciliation of Real Estate Investments and Accumulated Depreciation) (Parentheticals) (Details) - USD ($)		Jan. 14, 2016	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at the Beginning of the Year			$ 4,487,588,000		$ 4,631,128,000		$ 4,669,289,000
Additions:
Acquisitions			0		182,381,000		0
Capital expenditures and assets placed into service			213,996,000		165,941,000		132,149,000
Less:
Retirements			(79,022,000)		(49,535,000)		(43,839,000)
Balance at the end of the year			3,659,886,000		4,487,588,000		4,631,128,000
Assets held for sale	[1],[2]		(73,591,000)	[3]	(794,588,000)	[3]	(27,436,000)
Operating properties			3,586,295,000		3,693,000,000		4,603,692,000
Dispositions/impairments/placed into redevelopment			(962,676,000)		(442,327,000)		(126,471,000)
Tax Basis of Assets, Cost for Income Tax Purposes			3,000,000,000		3,900,000,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at the beginning of the year			1,080,616,000		1,078,996,000		983,808,000
Real Estate Accumulated Depreciation Additions [Abstract]
Depreciation expense			131,859,000		159,080,000		160,641,000
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Retirements			(76,973,000)		(48,217,000)		(42,994,000)
Balance at the end of the year			885,392,000		1,080,616,000		1,078,996,000
Assets held for sale			(32,916,000)		(213,581,000)		(11,167,000)
Real Estate Investment Property, Accumulated Depreciation			852,476,000		867,035,000
Dispositions/impairments/placed into redevelopment			(250,110,000)		(109,243,000)		(22,459,000)
Extinguishment of Debt, Amount			0		0		376,174,000
Aggregate carrying value			25,800,000
Impairment of properties held for use			7,300,000
Estimated Fair Value Of Impaired Property			18,500,000
Land and Building [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Provision for impairment on assets held for sale			3,000,000
Aggregate carrying value			13,300,000
Estimated closing costs			10,300,000
Land and Building [Member] | 1200 and 1220 Concord Avenue in Concord [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Provision for impairment on assets held for sale			11,500,000
Aggregate carrying value			43,500,000
Estimated closing costs			32,000,000
Secured Debt [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Extinguishment of Debt, Amount		$ 44,400,000
Repayments of debt		35,500,000
Repayment of prepayment charges		$ 8,900,000
Accumulated Depreciation, including HFS [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Real Estate Investment Property, Accumulated Depreciation			$ 852,476,000		$ 867,035,000		$ 1,067,829,000
[1]	As of December 31, 2015, 2970 Market Street was classified as held for sale on the consolidated balance sheets. The property was sold on February 5, 2016. See Note 21, "Subsequent Events," for further information. The sale is not classified as a significant disposition under the accounting guidance for discontinued operations.
[2]	As of December 31, 2015, the 58 properties associated with the series of related transactions with Och-Ziff Real Estate were classified as held for sale on the consolidated balance sheets. On February 4, 2016, the Company completed a series of transactions, resulting in the disposition of the properties. See Note 3, “Real Estate Investments,” for further information regarding the disposition. Additionally, as of December 31, 2016, the Company categorized three office properties located in the Metropolitan Washington, D.C. segment and two properties in the Other segment as held for sale in accordance with applicable accounting standards for long lived assets. See Note 3, “Real Estate Investments,” for further information.
[3]	Real estate investments related to assets held for sale above represents gross real estate assets and does not include accumulated depreciation or other assets on the balance sheets of the properties held for sale. See Held for Sale section below.