Brandywine Operating Partnership 10-K 29 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information Document - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 19, 2016	Jun. 30, 2015
Entity Registrant Name	BRANDYWINE REALTY TRUST
Entity Central Index Key	790,816
Document Type	10-K
Document Period End Date	Dec. 31, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
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			$ 2,360,378,871
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		174,822,400
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, 2015
Amendment Flag	false
Document Fiscal Year Focus	2,015
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, 2015	Dec. 31, 2014
Real estate investments:
Operating properties	$ 3,693,000	$ 4,603,692
Accumulated depreciation	(867,035)	(1,067,829)
Operating real estate investments, net	2,825,965	3,535,863
Construction-in-progress	268,983	201,360
Land held for development	130,479	90,603
Total real estate investments, net	3,225,427	3,827,826
Cash and cash equivalents	56,694	257,502
Accounts receivable, net	17,126	18,757
Accrued rent receivable, net	145,092	134,051
Assets held for sale, net	584,365	18,295
Investment in Real Estate Ventures, at equity	241,004	225,004
Deferred costs, net	101,419	101,261
Intangible assets, net	111,623	99,403
Mortgage note receivable	0	88,000
Other assets	71,761	65,111
Total assets	4,554,511	4,835,210
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable, net	545,753	639,631
Unsecured term loans, net	247,800	198,923
Unsecured senior notes, net	1,591,164	1,588,791
Accounts payable and accrued expenses	99,856	96,046
Distributions payable	28,249	28,871
Deferred income, gains and rent	30,413	59,452
Acquired lease intangibles, net	25,655	26,010
Liabilities related to assets held for sale	2,151	602
Other liabilities	31,379	37,558
Total liabilities	$ 2,602,420	$ 2,675,884
Commitments and contingencies
Equity:
6.90% Series E Preferred Shares, $0.01 par value; issued and outstanding- 4,000,000 in 2015 and 2014	$ 40	$ 40
Common Shares of Brandywine Realty Trust's beneficial interest, $0.01 par value; shares authorized 400,000,000; 174,688,568 and 179,293,160 issued and outstanding in 2015 and 2014, respectively	1,747	1,793
Additional paid-in-capital	3,252,622	3,314,693
Deferred compensation payable in common shares	11,918	6,219
Common shares in grantor trust, 745,686 in 2015, 384,536 in 2014	(11,918)	(6,219)
Cumulative earnings	499,086	529,487
Accumulated other comprehensive loss	(5,192)	(4,607)
Cumulative distributions	(1,814,378)	(1,700,579)
Total Brandywine Realty Trust's equity	1,933,925	2,140,827
Non-controlling interests	18,166	18,499
Total beneficiaries' equity	1,952,091	2,159,326
Total liabilities and beneficiaries' equity	4,554,511	4,835,210
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Real estate investments:
Operating properties	3,693,000	4,603,692
Accumulated depreciation	(867,035)	(1,067,829)
Operating real estate investments, net	2,825,965	3,535,863
Construction-in-progress	268,983	201,360
Land held for development	130,479	90,603
Total real estate investments, net	3,225,427	3,827,826
Cash and cash equivalents	56,694	257,502
Accounts receivable, net	17,126	18,757
Accrued rent receivable, net	145,092	134,051
Assets held for sale, net	584,365	18,295
Investment in Real Estate Ventures, at equity	241,004	225,004
Deferred costs, net	101,419	101,261
Intangible assets, net	111,623	99,403
Mortgage note receivable	0	88,000
Other assets	71,761	65,111
Total assets	4,554,511	4,835,210
LIABILITIES AND BENEFICIARIES' EQUITY
Mortgage notes payable, net	545,753	639,631
Unsecured term loans, net	247,800	198,923
Unsecured senior notes, net	1,591,164	1,588,791
Accounts payable and accrued expenses	99,856	96,046
Distributions payable	28,249	28,871
Deferred income, gains and rent	30,413	59,452
Acquired lease intangibles, net	25,655	26,010
Liabilities related to assets held for sale	2,151	602
Other liabilities	31,379	37,558
Total liabilities	$ 2,602,420	$ 2,675,884
Commitments and contingencies
Redeemable limited partnership units at redemption value; 1,535,102 issued and outstanding in 2015 and 2014	$ 22,114	$ 24,571
Equity:
6.90% Series E Preferred Shares, $0.01 par value; issued and outstanding- 4,000,000 in 2015 and 2014	96,850	96,850
General Partnership Capital 174,688,568 and 179,293,160 units issued and outstanding in 2015 and 2014, respectively	1,836,692	2,041,902
Accumulated other comprehensive loss	(5,597)	(5,007)
Total Brandywine Realty Trust's equity	1,927,945	2,133,745
Non-controlling interests	2,032	1,010
Total beneficiaries' equity	1,929,977	2,134,755
Total liabilities and beneficiaries' equity	$ 4,554,511	$ 4,835,210

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
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	174,688,568	179,293,160
Common Stock, Shares, Outstanding	174,688,568	179,293,160
Common Shares in Grantor Trust	745,686	384,536
BRANDYWINE OPERATING PARTNERSHIP, L.P.
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	1,535,102	1,535,102
Redeemable Limited Partnership Units Outstanding	1,535,102	1,535,102
General Partners' Capital Account, Units Issued	174,688,568	179,293,160
General Partners' Capital Account, Units Outstanding	174,688,568	179,293,160

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue
Rents	$ 486,731	$ 483,682	$ 461,387
Tenant reimbursements	85,722	84,879	79,087
Termination fees	4,797	8,000	4,497
Third party management fees, labor reimbursement and leasing	18,764	17,200	13,053
Other	6,617	3,221	4,186
Total revenue	602,631	596,982	562,210
Operating expenses:
Property operating expenses	181,170	177,330	160,406
Real estate taxes	50,623	51,844	55,612
Third party management expenses	6,294	6,791	5,751
Depreciation and amortization	219,029	208,569	197,021
General and administrative expenses	29,406	26,779	27,628
Provision for impairment	82,208	1,765	0
Total operating expenses	568,730	473,078	446,418
Operating income	33,901	123,904	115,792
Other income (expense):
Interest income	1,224	3,974	1,044
Tax credit transaction income	19,955	11,853	11,853
Interest expense	(110,717)	(124,329)	(121,937)
Interest expense - amortization of deferred financing costs	(4,557)	(5,148)	(4,676)
Interest expense - financing obligation	(1,237)	(1,144)	(972)
Recognized hedge activity	0	(828)	0
Equity in income (loss) of Real Estate Ventures	(811)	(790)	3,664
Net gain on disposition of real estate	20,496	4,901	0
Net gain (loss) on sale of undepreciated real estate	3,019	1,184	(137)
Net gain from remeasurement of investments in real estate ventures	758	458	6,866
Net gain (loss) on real estate venture transactions	7,229	(417)	29,604
Loss on early extinguishment of debt	0	(7,594)	(2,119)
Income (loss) from continuing operations	(30,740)	6,024	38,982
Discontinued operations:
Income from discontinued operations	0	18	825
Net gain on disposition of discontinued operations	0	900	3,382
Total discontinued operations	0	918	4,207
Net income (loss)	(30,740)	6,942	43,189
Net income from discontinued operations attributable to non-controlling interests	0	(10)	(55)
Net (income) loss from continuing operations attributable to non-controlling interests	339	43	(357)
Net (income) loss attributable to non-controlling interests	339	33	(412)
Net income (loss) attributable to Brandywine Realty Trust	(30,401)	6,975	42,777
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Nonforfeitable dividends allocated to unvested restricted shareholders	(329)	(349)	(363)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ (37,630)	$ (274)	$ 35,514
Basic income (loss) per Common Share:
Continuing operations (USD per share)	$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations (USD per share)	0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)	(0.21)	0	0.23
Diluted income (loss) per Common Share:
Continuing operations (USD per share)	(0.21)	(0.01)	0.20
Discontinued operations (USD per share)	0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.21)	$ 0	$ 0.23
Basic weighted average shares outstanding (in shares)	178,162,160	166,202,649	153,140,458
Diluted weighted average shares outstanding (in shares)	178,162,160	166,202,649	154,414,311
Net income (loss) attributable to Brandywine Realty Trust
Total continuing operations	$ (30,401)	$ 6,067	$ 38,625
Total discontinued operations	0	908	4,152
Net income (loss)	(30,401)	6,975	42,777
Net income (loss)	$ (30,740)	$ 6,942	$ 43,189
Distributions declared per Common Share (USD per share)	$ 0.60	$ 0.60	$ 0.60
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Revenue
Rents	$ 486,731	$ 483,682	$ 461,387
Tenant reimbursements	85,722	84,879	79,087
Termination fees	4,797	8,000	4,497
Third party management fees, labor reimbursement and leasing	18,764	17,200	13,053
Other	6,617	3,221	4,186
Total revenue	602,631	596,982	562,210
Operating expenses:
Property operating expenses	181,170	177,330	160,406
Real estate taxes	50,623	51,844	55,612
Third party management expenses	6,294	6,791	5,751
Depreciation and amortization	219,029	208,569	197,021
General and administrative expenses	29,406	26,779	27,628
Provision for impairment	82,208	1,765	0
Total operating expenses	568,730	473,078	446,418
Operating income	33,901	123,904	115,792
Other income (expense):
Interest income	1,224	3,974	1,044
Tax credit transaction income	19,955	11,853	11,853
Interest expense	(110,717)	(124,329)	(121,937)
Interest expense - amortization of deferred financing costs	(4,557)	(5,148)	(4,676)
Interest expense - financing obligation	(1,237)	(1,144)	(972)
Recognized hedge activity	0	(828)	0
Equity in income (loss) of Real Estate Ventures	(811)	(790)	3,664
Net gain on disposition of real estate	20,496	4,901	0
Net gain (loss) on sale of undepreciated real estate	3,019	1,184	(137)
Net gain from remeasurement of investments in real estate ventures	758	458	6,866
Net gain (loss) on real estate venture transactions	7,229	(417)	29,604
Loss on early extinguishment of debt	0	(7,594)	(2,119)
Income (loss) from continuing operations	(30,740)	6,024	38,982
Discontinued operations:
Income from discontinued operations	0	18	825
Net gain on disposition of discontinued operations	0	900	3,382
Total discontinued operations	0	918	4,207
Net income (loss)	(30,740)	6,942	43,189
Net (income) loss from continuing operations attributable to non-controlling interests	3	44	0
Net income (loss) attributable to Brandywine Realty Trust	(30,737)	6,986	43,189
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Nonforfeitable dividends allocated to unvested restricted shareholders	(329)	(349)	(363)
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust	$ (37,966)	$ (263)	$ 35,926
Basic income (loss) per Common Share:
Continuing operations (USD per share)	$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations (USD per share)	0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)	(0.21)	0	0.23
Diluted income (loss) per Common Share:
Continuing operations (USD per share)	(0.21)	(0.01)	0.20
Discontinued operations (USD per share)	0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.21)	$ 0	$ 0.23
Basic weighted average shares outstanding (in shares)	179,697,262	167,942,246	154,929,545
Diluted weighted average shares outstanding (in shares)	179,697,262	167,942,246	156,203,398
Net income (loss) attributable to Brandywine Realty Trust
Total continuing operations	$ (30,740)	$ 6,024	$ 38,982
Total discontinued operations	0	918	4,207
Net income (loss)	(30,737)	6,986	43,189
Net income (loss)	$ (30,740)	$ 6,942	$ 43,189
Distributions declared per Common Share (USD per share)	$ 0.60	$ 0.60	$ 0.60

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income (loss)		$ (30,740)	$ 6,942	$ 43,189
Comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments		(1,010)	(1,190)	12,789
Loss on settlement of interest rate swaps		0	(828)	0
Reclassification of realized losses on derivative financial instruments to operations, net	[1]	420	388	286
Total comprehensive income (loss)		(590)	(1,630)	13,075
Comprehensive income (loss)		(31,330)	5,312	56,264
Comprehensive income (loss) attributable to non-controlling interest		344	51	(564)
Comprehensive income (loss) attributable to reporting entity		(30,986)	5,363	55,700
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Net income (loss)		(30,740)	6,942	43,189
Comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments		(1,010)	(1,190)	12,789
Loss on settlement of interest rate swaps		0	(828)	0
Reclassification of realized losses on derivative financial instruments to operations, net	[2]	420	388	286
Total comprehensive income (loss)		(590)	(1,630)	13,075
Comprehensive income (loss) attributable to non-controlling interest		3	44	0
Comprehensive income (loss) attributable to reporting entity		$ (31,327)	$ 5,356	$ 56,264
[1]	(1) Amounts reclassified from comprehensive income to interest expense within the Consolidated Statements of Operations.
[2]	(1) 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 Income (Loss) [Member]	Cumulative Distributions [Member]	Noncontrolling Interest [Member]
Beginning Balance, Shares at Dec. 31, 2012		4,000,000	143,538,733	290,745
Beginning Balance at Dec. 31, 2012	$ 1,773,516	$ 40	$ 1,434	$ 5,352	$ 2,780,194	$ (5,352)	$ 479,734	$ (15,918)	$ (1,493,206)	$ 21,238
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	43,189						42,777			412
Other comprehensive income	13,075							12,923		152
Issuance of Common Shares of Beneficial Interest, Shares			12,650,000
Issuance of Common Shares of Beneficial Interest	182,034		$ 127		181,907
Issuance of partnership interest in joint venture	946									946
Equity issuance costs	(744)				(744)
Conversion of LP Units to Common Shares, Shares			81,998
Conversion of LP Units to Common Shares			$ 1		1,239					(1,240)
Bonus share issuance, Shares			27,918
Bonus share issuance	361				361
Share-based compensation activity, Shares			438,356	34,117
Share-based compensation activity	9,438		$ 4		9,417		17
Share Issuance from/to Deferred Compensation Plan, Shares			(5,012)	(12,583)
Share issuance from/to Deferred Compensation Plan				$ 55		(55)
Adjustment to Non-controlling Interest					(778)					778
Preferred Share distributions	(6,900)								(6,900)
Distributions declared	(93,480)								(92,409)	(1,071)
Ending Balance, Shares at Dec. 31, 2013		4,000,000	156,731,993	312,279
Ending 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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	6,942						6,975			(33)
Other comprehensive income	(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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(30,740)						(30,401)			(339)
Other comprehensive income	$ (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 Common Shares of Beneficial Interest	1,025									1,025
Equity issuance costs	(105)				(105)
Bonus share issuance, Shares			8,447
Bonus share issuance	$ 125				125
Share-based compensation activity, Shares	5,097		509,675	280,011
Share-based compensation activity			$ 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

Consolidated Statements of Ben7

Consolidated Statements of Beneficiaries' Equity (Paranthetical) - $ / shares	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015
Dividends declared (USD per share)	$ 0.60	$ 0.60	$ 0.60
Cumulative Distributions [Member]
Dividends declared (USD per share)	0.60	0.60	0.60
Noncontrolling Interest [Member]
Dividends declared (USD per share)	$ 0.60	$ 0.60	$ 0.60

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income (loss)	$ (30,740)	$ 6,942	$ 43,189
Adjustments to reconcile net (loss) income to net cash from operating activities:
Depreciation and amortization	219,029	208,569	198,731
Amortization of deferred financing costs	4,557	5,148	4,676
Amortization of debt discount/(premium), net	(755)	(531)	2,480
Amortization of stock compensation costs	5,065	4,137	6,998
Shares used for employee taxes upon vesting of share awards	(2,055)	(1,177)	(1,062)
Recognized hedge activity	0	828	0
Settlement of hedge transaction	(5,266)	0	0
Straight-line rent income	(23,668)	(16,046)	(20,136)
Amortization of acquired above (below) market leases, net	(7,960)	(6,377)	(7,170)
Straight-line ground rent expense	88	89	1,509
Provision for doubtful accounts	2,489	1,763	2,467
Net (gain) loss on real estate venture transactions	(7,418)	417	(3,683)
Net gain on sale of interests in real estate	(23,515)	(6,085)	(29,166)
Preacquisition cost write-off	1,299	0	0
Net gain from remeasurement of investment in a real estate venture	(758)	(458)	(6,866)
Loss on early extinguishment of debt	0	7,594	2,119
Provision for impairment	82,208	1,765	0
Tax credit transaction income	(19,955)	(11,853)	(11,853)
Real Estate Venture (income) loss in excess of distributions	2,034	1,954	(2,014)
Deferred financing obligation	(1,237)	(1,147)	(974)
Changes in assets and liabilities
Accounts receivable	(848)	(2,869)	(4,048)
Other assets	837	(4,111)	5,440
Accounts payable and accrued expenses	4,083	962	(526)
Deferred income, gains and rent	(521)	2,436	3,758
Other liabilities	(1,894)	(2,951)	(385)
Net cash provided by operating activities	195,099	188,999	183,484
Cash flows from investing activities:
Acquisition of properties	(150,472)	(18,443)	(161,604)
Acquisition of property - 1031 exchange funds applied	(62,812)	0	0
Proceeds from the sale of properties	247,228	118,855	423,480
Sale of property - 1031 exchange funds held in escrow	62,800	0	0
Net proceeds from the contribution of properties to an unconsolidated real estate venture	50,158	0	0
Net proceeds from the contribution of land to an unconsolidated real estate venture	0	8,212	0
Distribution of sales proceeds from a real estate venture	6,100	0	16,963
Loan provided to an unconsolidated real estate venture	0	(88,000)	0
Proceeds from repayment of mortgage notes receivable	88,000	7,026	200
Capital expenditures for tenant improvements	(97,851)	(131,077)	(109,357)
Capital expenditures for redevelopments	(48,367)	(19,245)	(6,265)
Capital expenditures for developments	(179,927)	(86,608)	(5,490)
Reimbursement from real estate venture for pre-formation development costs	0	0	1,976
Advances for the purchase of tenant assets, net of repayments	308	(540)	(127)
Investment in unconsolidated Real Estate Ventures	(68,549)	(46,098)	(33,069)
Deposits for real estate	(878)	0	0
Escrowed cash	516	283	1,902
Cash distribution from unconsolidated Real Estate Ventures in excess of cumulative equity income	8,557	9,767	7,496
Leasing costs paid	(21,263)	(24,917)	(31,397)
Net cash (used in) from investing activities	(166,452)	(270,785)	104,708
Cash flows from financing activities:
Repayments of mortgage notes payable	(222,836)	(13,441)	(11,268)
Repayments of unsecured term loan	0	(250,828)	0
Proceeds from credit facility borrowings	89,000	0	186,000
Repayments of credit facility borrowings	(89,000)	0	(255,000)
Proceeds from term loan borrowings	50,000	0	0
Proceeds from mortgage notes payable	130,000	0	0
Net proceeds from unsecured notes	0	496,459	0
Net proceeds from issuance of common shares\units	0	335,016	181,527
Repayments of unsecured notes	0	(383,768)	(31,369)
Debt financing costs paid	(5,202)	(3,705)	(355)
Proceeds from the exercise of stock options	127	2,143	2,381
Partner contribution to consolidated real estate venture	1,025	0	0
Repurchase and retirement of common shares	(67,320)	0	0
Distributions paid to shareholders	(114,328)	(104,731)	(97,367)
Distributions to non-controlling interest	(921)	(1,064)	(1,083)
Net cash (used in) from financing activities	(229,455)	76,081	(26,534)
(Decrease) Increase in cash and cash equivalents	(200,808)	(5,705)	261,658
Cash and cash equivalents at beginning of year	257,502	263,207	1,549
Cash and cash equivalents at end of year	56,694	257,502	263,207
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2015, 2014 and 2013 of $12,150, $6,802 and $3,137, respectively	124,953	129,160	118,714
Supplemental disclosure of non-cash activity:
Change in real estate investments related to a non-cash acquisition of an operating property	0	0	(21,649)
Change in operating real estate due to non-cash adjustment to land	0	0	7,752
Change in intangible assets, net related to non-cash acquisition of an operating property	0	0	(3,517)
Change in acquired lease intangibles, net related to non-cash acquisition of an operating property	0	0	462
Change in investments in joint venture related to non-cash disposition of property	(25,127)	(5,897)	(17,628)
Change in operating real estate related to non-cash property disposition	25,127	0	0
Change in real estate investments related to non-cash property acquisition	(66,324)	0	0
Change in investments in joint venture related to non-cash acquisition of property	66,324	0	0
Change in investments in joint venture related to a contribution of land at period end	0	(1,182)	(6,058)
Change in mortgage notes payable related to acquisition of an operating property	0	0	238,082
Change in receivable from settlement of acquisitions	0	619	0
Change in other liabilities from contingent consideration related to a business combination	1,585	0	0
Change in operating real estate from contingent consideration related to a business combination	(1,585)	0	0
Change in other liabilities from deferred payment related to a asset acquisition	2,000	0	0
Change in operating real estate from deferred payment related to an asset acquisition	(2,000)	0	0
Change in capital expenditures financed through accounts payable at period end	(7,654)	7,336	11,703
Change in capital expenditures financed through retention payable at period end	6,104	6,164	(204)
Change in unfunded tenant allowance	(273)	(955)	(969)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Cash flows from operating activities:
Net income (loss)	(30,740)	6,942	43,189
Adjustments to reconcile net (loss) income to net cash from operating activities:
Depreciation and amortization	219,029	208,569	198,731
Amortization of deferred financing costs	4,557	5,148	4,676
Amortization of debt discount/(premium), net	(755)	(531)	2,480
Amortization of stock compensation costs	5,065	4,137	6,998
Shares used for employee taxes upon vesting of share awards	(2,055)	(1,177)	(1,062)
Recognized hedge activity	0	828	0
Settlement of hedge transaction	(5,266)	0	0
Straight-line rent income	(23,668)	(16,046)	(20,136)
Amortization of acquired above (below) market leases, net	(7,960)	(6,377)	(7,170)
Straight-line ground rent expense	88	89	1,509
Provision for doubtful accounts	2,489	1,763	2,467
Net (gain) loss on real estate venture transactions	(7,418)	417	(3,683)
Net gain on sale of interests in real estate	(23,515)	(6,085)	(29,166)
Preacquisition cost write-off	1,299	0	0
Net gain from remeasurement of investment in a real estate venture	(758)	(458)	(6,866)
Loss on early extinguishment of debt	0	7,594	2,119
Provision for impairment	82,208	1,765	0
Tax credit transaction income	(19,955)	(11,853)	(11,853)
Real Estate Venture (income) loss in excess of distributions	2,034	1,954	(2,014)
Deferred financing obligation	(1,237)	(1,147)	(974)
Changes in assets and liabilities
Accounts receivable	(848)	(2,869)	(4,048)
Other assets	837	(4,111)	5,440
Accounts payable and accrued expenses	4,083	962	(526)
Deferred income, gains and rent	(521)	2,436	3,758
Other liabilities	(1,894)	(2,951)	(385)
Net cash provided by operating activities	195,099	188,999	183,484
Cash flows from investing activities:
Acquisition of properties	(150,472)	(18,443)	(161,604)
Acquisition of property - 1031 exchange funds applied	(62,812)	0	0
Proceeds from the sale of properties	247,228	118,855	423,480
Sale of property - 1031 exchange funds held in escrow	62,800	0	0
Net proceeds from the contribution of properties to an unconsolidated real estate venture	50,158	0	0
Net proceeds from the contribution of land to an unconsolidated real estate venture	0	8,212	0
Distribution of sales proceeds from a real estate venture	6,100	0	16,963
Loan provided to an unconsolidated real estate venture	0	(88,000)	0
Proceeds from repayment of mortgage notes receivable	88,000	7,026	200
Capital expenditures for tenant improvements	(97,851)	(131,077)	(109,357)
Capital expenditures for redevelopments	(48,367)	(19,245)	(6,265)
Capital expenditures for developments	(179,927)	(86,608)	(5,490)
Reimbursement from real estate venture for pre-formation development costs	0	0	1,976
Advances for the purchase of tenant assets, net of repayments	308	(540)	(127)
Investment in unconsolidated Real Estate Ventures	(68,549)	(46,098)	(33,069)
Deposits for real estate	(878)	0	0
Escrowed cash	516	283	1,902
Cash distribution from unconsolidated Real Estate Ventures in excess of cumulative equity income	8,557	9,767	7,496
Leasing costs paid	(21,263)	(24,917)	(31,397)
Net cash (used in) from investing activities	(166,452)	(270,785)	104,708
Cash flows from financing activities:
Repayments of mortgage notes payable	(222,836)	(13,441)	(11,268)
Repayments of unsecured term loan	0	(250,828)	0
Proceeds from credit facility borrowings	89,000	0	186,000
Repayments of credit facility borrowings	(89,000)	0	(255,000)
Proceeds from term loan borrowings	50,000	0	0
Proceeds from mortgage notes payable	130,000	0	0
Net proceeds from unsecured notes	0	496,459	0
Net proceeds from issuance of common shares\units	0	335,016	181,527
Repayments of unsecured notes	0	(383,768)	(31,369)
Debt financing costs paid	(5,202)	(3,705)	(355)
Proceeds from the exercise of stock options	127	2,143	2,381
Partner contribution to consolidated real estate venture	1,025	0	0
Repurchase and retirement of common shares	(67,320)	0	0
Distributions paid to shareholders	(115,249)	(105,795)	(98,450)
Net cash (used in) from financing activities	(229,455)	76,081	(26,534)
(Decrease) Increase in cash and cash equivalents	(200,808)	(5,705)	261,658
Cash and cash equivalents at beginning of year	257,502	263,207	1,549
Cash and cash equivalents at end of year	56,694	257,502	263,207
Supplemental disclosure:
Cash paid for interest, net of capitalized interest during the years ended December 31, 2015, 2014 and 2013 of $12,150, $6,802 and $3,137, respectively	124,953	129,160	118,714
Supplemental disclosure of non-cash activity:
Change in real estate investments related to a non-cash acquisition of an operating property	0	0	(21,649)
Change in operating real estate due to non-cash adjustment to land	0	0	7,752
Change in intangible assets, net related to non-cash acquisition of an operating property	0	0	(3,517)
Change in acquired lease intangibles, net related to non-cash acquisition of an operating property	0	0	462
Change in investments in joint venture related to non-cash disposition of property	(25,127)	(5,897)	(17,628)
Change in operating real estate related to non-cash property disposition	25,127	0	0
Change in real estate investments related to non-cash property acquisition	(66,324)	0	0
Change in investments in joint venture related to non-cash acquisition of property	66,324	0	0
Change in investments in joint venture related to a contribution of land at period end	0	(1,182)	(6,058)
Change in mortgage notes payable related to acquisition of an operating property	0	0	238,082
Change in receivable from settlement of acquisitions	0	619	0
Change in other liabilities from contingent consideration related to a business combination	1,585	0	0
Change in operating real estate from contingent consideration related to a business combination	(1,585)	0	0
Change in other liabilities from deferred payment related to a asset acquisition	2,000	0	0
Change in operating real estate from deferred payment related to an asset acquisition	(2,000)	0	0
Change in capital expenditures financed through accounts payable at period end	(7,654)	7,336	11,703
Change in capital expenditures financed through retention payable at period end	6,104	6,164	(204)
Change in unfunded tenant allowance	$ (273)	$ (955)	$ (969)

Consolidated Statements of Cas9

Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of capitalized interest during the years ended December 31, 2015, 2014 and 2013 of $12,150, $6,802 and $3,137, respectively	$ 12,150	$ 6,802	$ 3,137
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Supplemental Cash Flow Information [Abstract]
Cash paid for interest, net of capitalized interest during the years ended December 31, 2015, 2014 and 2013 of $12,150, $6,802 and $3,137, respectively	$ 12,150	$ 6,802	$ 3,137

Consolidated Statement of Partn

Consolidated Statement 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 Income (Loss) [Member]	Accumulated Other Comprehensive Income (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, 2012	$ 1,773,516	$ 1,746,739	$ 1,666,341	$ 96,850	$ (15,918)	$ (16,452)	$ 21,238	$ 0
Beginning Balance, Shares at Dec. 31, 2012			143,538,733	4,000,000
Net income (loss) attributable to Brandywine Realty Trust	42,777	43,189	$ 43,189
Other comprehensive income	13,075	13,075			12,923	13,075	152
Share Issuance from/to Deferred Compensation Plan, Shares			(5,012)
Issuance of LP Units		181,289	$ 181,289
Issuance of LP Units, Shares			12,650,000
Issuance of partnership interest in real estate		946						946
Bonus share issuance	361	361	$ 361
Bonus share issuance, Shares			27,918
Conversion of LP Units to Common Shares		1,240	$ 1,240				(1,240)
Conversion of LP Units to Common Shares, Shares			81,998
Share-based compensation activity	9,438	9,437	$ 9,437
Share-based compensation activity, Shares			438,356
Adjustment of redeemable partnership units to liquidation value at period end		(778)	$ (778)
Redemption value of limited partnership units		(1,240)	(1,240)
Distribution to preferred shareholders	(6,900)	(6,900)	(6,900)
Distributions to general partnership unitholders		(92,409)	(92,409)
Ending Balance at Dec. 31, 2013	1,921,435	1,894,949	$ 1,800,530	$ 96,850	(2,995)	(3,377)	21,215	946
Ending Balance, Shares at Dec. 31, 2013			156,731,993	4,000,000
Net income (loss) attributable to Brandywine Realty Trust	6,975	6,986	$ 6,942					(44)	$ 6,898
Other comprehensive income	(1,630)	(1,630)			(1,612)	(1,630)	(18)
Deferred compensation obligation		(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	2,159,326	2,134,755	$ 2,041,902	$ 96,850	(4,607)	(5,007)	18,499	1,010
Ending Balance, Shares at Dec. 31, 2014			179,293,160	4,000,000
Net income (loss) attributable to Brandywine Realty Trust	(30,401)	(30,737)	$ (30,740)					3
Other comprehensive income	(590)	(590)			(585)	(590)	(5)
Deferred compensation obligation		(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 real estate		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
Share-based compensation activity, Shares	5,097		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	$ 1,952,091	$ 1,929,977	$ 1,836,692	$ 96,850	$ (5,192)	$ (5,597)	$ 18,166	$ 2,032
Ending Balance, Shares at Dec. 31, 2015			174,688,568	4,000,000

Organization of the Parent Comp

Organization of the Parent Company and The Operating Partnership	12 Months Ended
	Dec. 31, 2015
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 and industrial 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, 2015, 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, 2015, the Company owned 179 properties, consisting of 106 office properties, six industrial facilities, three mixed-use properties, one retail property (116 core properties), two development properties, 59 properties classified as held for sale, one redevelopment property and one re-entitlement property (collectively, the “Properties”) containing an aggregate of approximately 23.0 million net rentable square feet. In addition, as of December 31, 2015, the Company owned economic interests in 16 unconsolidated real estate ventures that contain approximately 4.3 million net rentable square feet (collectively, the “Real Estate Ventures”). As of December 31, 2015, the Company also owned 412 acres of undeveloped land, of which 120 acres were held for sale, and held options to purchase a parcel containing approximately 50 additional acres of undeveloped land. As of December 31, 2015, the total potential development that these land parcels could support, under current zoning, entitlements or combination thereof, amounted to an estimated 7.1 million square feet. The Properties and the properties owned by the Real Estate Ventures are located in or near Philadelphia, Pennsylvania; Metropolitan Washington, D.C.; Southern New Jersey; Richmond, Virginia; Wilmington, Delaware; Austin, Texas and Oakland and Concord, California. In addition to managing properties that the Company owns, as of December 31, 2015, the Company was managing approximately 6.5 million net rentable square feet of office and industrial properties for third parties and Real Estate Ventures. 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, 2015, the Operating Partnership owns, directly and indirectly, 100% of each of BRSCO, BTRS, BPI, BBL, BPM and BBS. As of December 31, 2015, the Management Companies were managing properties containing an aggregate of approximately 29.5 million net rentable square feet, of which approximately 23.0 million net rentable square feet related to Properties owned by the Company and approximately 6.5 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, 2015
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	2. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Reclassifications Reclassifications are related to the treatment of sold properties as discontinued operations on the statement of operations for all periods presented. During the fourth quarter of 2015, the Company adopted ASU 2015-03, Simplifying the Presentation of Debt Issuances Costs (“ASU 2015-03”) eferred financing costs associated with our credit facility remain in deferred costs (assets) on the consolidated balance sheet Recent Accounting Pronouncements Principles of Consolidation When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity (“VIE”), and if the Company is deemed to be the primary beneficiary, in accordance with the accounting standard for the consolidation of variable interest entities. The accounting standard for the consolidation of VIEs requires the Company to qualitatively assess if the Company was the primary beneficiary of the VIEs based on whether the Company had (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 determined to be VIEs, but for which the Company is not the primary beneficiary, the Company’s maximum exposure to loss is the carrying amount of its investments. As of December 31, 2015, the Company has provided guarantees on behalf of certain real estate ventures, consisting of: (i) a $24.7 million payment guaranty on the construction loan for evo at Cira; (ii) a $3.2 million payment guarantee on the construction loan for TB-BDN Plymouth Apartments; (iii) a several cost overrun guaranty on the $88.9 million construction loan for the development project being undertaken by 1919 Ventures; and (iv) a $0.5 million payment guarantee on a loan provided to PJP VII. When an entity is not deemed to be a VIE, the Company considers the provisions of the same accounting standard to determine whether a general partner/managing member, or the general partners/managing members as a group, controls a limited partnership or similar entity when the limited partners/non-managing members have certain rights. The Company consolidates (i) entities that are VIEs and of which the Company is deemed to be the primary beneficiary and (ii) entities that are non-VIEs and are controlled by the Company and in which the limited partners neither have the ability to dissolve the entity or remove the Company without cause nor any substantive participating rights. The Company continuously assesses its determination of whether an entity is a VIE and who the primary beneficiary is, and whether or not the limited partners/non-managing members in an entity have substantive rights, more particularly if certain events occur that are likely to cause a change in the original determinations. The Company’s assessment includes a review of applicable documents such as, but not limited to, applicable partnership agreements, limited liability company and other real estate venture agreements and management and leasing agreements to determine whether the Company has control to direct the business activities of the entities. 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, 2015, the Company included in its consolidated balance sheets consolidated VIEs having total assets of $422.9 million and total liabilities of $258.2 million. 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, 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. Major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives. 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 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 rentals 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. Though the Company considers the value of tenant relationships, the amounts are determined on a tenant-specific basis. On certain of our acquisitions this intangible has been deemed immaterial. In these instances no related intangible 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 $7.3 million in 2015, $5.2 million in 2014, $3.7 million in 2013 and interest totaling $10.2 million in 2015, $4.8 million in 2014, and $2.6 million in 2013 were capitalized related to development of certain properties and land holdings. The increase in capitalized costs is due to the development activity. See Item 1., “ Business - Developments, During the years ended December 31, 2015, 2014 and 2013, 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, 2015 2014 2013 Development $ 2,641 $ 1,749 $ 156 Redevelopment 221 184 194 Tenant Improvements 4,429 3,261 3,323 Total $ 7,291 $ 5,194 $ 3,673 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 our impairment analysis. The Company update 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. 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 our 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 consider assets to be “held for sale” when the transaction has been approved by our 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 equal to the difference and reduces the net carrying value of the property. 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). 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 financial institutions in excess of insured limits, but believes this risk is mitigated by only investing in or through major financial institutions. 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. Accounts Receivable and Accrued Rent Receivable 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 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, 2015 and 2014, 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 $1.7 million and $14.5 million in 2015, respectively and $2.0 million and $13.4 million in 2014, 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 The Company accounts for its investments in unconsolidated Real Estate Ventures under the equity method of accounting as it is not the primary beneficiary (for VIEs) and the Company exercises significant influence, but does not control these entities under the provisions of the entities’ governing agreements pursuant to the accounting standard for the consolidation of VIEs. When the Company determines that its investment in an unconsolidated Real Estate Venture does not constitute a VIE, the Company utilizes the voting interest model under the accounting standard for consolidation to determine whether to consolidate the venture. Under the equity method, investments in unconsolidated Real Estate Ventures are recorded initially at cost, as investments in Real Estate Ventures, and subsequently adjusted for equity in earnings, cash contributions, less 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. In each of the twelve months ended December 31, 2015 and 2014 the Company capitalized interest expense of $2.0 million. During the twelve months ended December 31, 2013, the Company capitalized interest expense of $0.6 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 15 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. On October 17, 2014, the Austin Venture acquired River Place (See Note 4, “ Investment in Unconsolidated Real Estate Ventures Deferred Financing Costs Costs incurred in connection with debt financing are capitalized as deferred financing costs and 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 During the fourth quarter of 2015, the Company adopted accounting guidance related to the presentation of deferred financing costs on the balance sheet and reclassified amounts from the deferred costs line (assets) to net against the debt liability for all periods presented. See Recent Accounting Pronouncements 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 $21.6 million in 2015, $13.7 million in 2014 and $17.7 million in 2013. 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 $2.0 million in 2015 and $2.4 million in each of 2014 and 2013. 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 $1.8 million in 2015, $1.5 million in 2014, and $0.7 million in 2013. 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. 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. 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. 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, management fees and development fees from third parties. 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 write 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. No tenant represented greater than 10% of the Company’s rental revenue in 2015, 2014 or 2013. 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, no 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 $3.9 billion and $3.7 billion for the years ended December 31, 2015 and 2014, 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 2015, 2014 or 2013. 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, 2015 and 2014. 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. We expect that the changes will not materially impact our 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 $3.9 billion and $3.7 billion for the years ended December 31, 2015 and 2014, 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

Real Estate Investments

Real Estate Investments	12 Months Ended
	Dec. 31, 2015
Real Estate [Abstract]
REAL ESTATE INVESTMENTS	3. REAL ESTATE INVESTMENTS As of December 31, 2015 and 2014 the gross carrying value of the Company’s Properties was as follows (in thousands): 2015 2014 Land $ 513,268 $ 669,635 Building and improvements 2,719,780 3,409,303 Tenant improvements 459,952 524,754 3,693,000 4,603,692 Assets held for sale - real estate investments (a) 794,588 27,436 Total $ 4,487,588 $ 4,631,128 (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 Acquisitions and Dispositions 2015 Acquisitions The Company completed each of the transactions described below with unaffiliated third parties in arms’ length transactions. 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 our 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. 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, we 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 Newark, DE / 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, net 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 our 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 our 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 Poperties) 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/(Loss) 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) less costs to sell exceeded the carrying value of the properties. The disposal of the properties referenced above does not represent a strategic shift that has a major effect on our operations and financial results. Accordingly, the operating results of these properties remain classified within continuing operations for all periods presented. 2013 Acquisitions One and Two Commerce Square On December 19, 2013, the Company acquired 99% of the common interests in the One and Two Common Square partnerships (“Commerce Square”), the entities which own two 41-story Trophy-class office towers in Philadelphia, Pennsylvania, from Parkway. The office towers contain 1,896,142 of net rentable square feet and were 86.7% occupied as of December 31, 2013. The Company acquired Commerce Square for an aggregate purchase price of $331.8 million and funded the acquisition via assumption of $237.1 million of existing mortgage debt and a $73.1 million cash payment from available corporate funds. The Company previously accounted for our non-controlling interest in Commerce Square under the equity method of accounting. As a result of acquiring a 99% common interest in the partnerships the Company obtained control of Commerce Square and our existing investment balance was remeasured based on the fair value of the underlying properties acquired and the existing distribution provisions under the relevant partnership agreements. Accordingly, a loss on remeasurement of $1.0 million was recorded as a result of this transaction. The Company has treated this transaction as a business combination and allocated the purchase price to the tangible and intangible assets and liabilities. As discussed in Note 2, 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 and intangible liabilities assumed. The purchase price is allocated as follows: December 19, 2013 Building, land and improvements $ 255,705 Intangible assets acquired 85,036 Below market lease liabilities assumed (8,637 ) $ 332,104 Mortgage debt assumed - at fair value (a) (238,082 ) Return of existing equity method investment (30,424 ) Net working capital assumed 10,423 Non-controlling interest (946 ) Total cash payment at settlement $ 73,075 (a) Principal outstanding on assumed mortgage debt at December 19, 2013 was $237.1 million. Intangible assets acquired and intangible liabilities assumed consist of the following (in thousands): December 19, 2013 Weighted Average Amortization Period (in years) Intangible assets: In-place lease value $ 80,916 7.9 Above market tenant leases acquired 4,120 6.9 Total $ 85,036 Intangible liabilities: Below market leases acquired $ (8,637 ) 6.5 In connection with the acquisition of One Commerce Square, the Company assumed a $125.1 million existing non-recourse first mortgage with a fixed interest rate of 5.67% and a maturity date of January 6, 2016. In accordance with generally accepted accounting principles, the mortgage was recorded at $130.2 million to reflect the fair value. 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. In connection with the acquisition of Two Commerce Square, the Company assumed a $112.0 million existing non-recourse first mortgage with a fixed interest rate of 3.96% and a maturity date of April 5, 2023. In accordance with generally accepted accounting principles, the mortgage was recorded at $107.9 million to reflect the fair value. The Company recognized $0.9 million of acquisition related costs which are included as part of general and administrative expenses of the Company’s consolidated statement of operations. Four Points Centre On December 19, 2013, the Company acquired two three-story, Class A office buildings totaling 192,396 of net rentable square feet known as Four Points Centre, together with 22.3 acres of nearby parcels of land in Austin, Texas known for an aggregate $47.3 million. This property was 99.2% occupied as of December 31, 2013. The Company funded the acquisition price with available corporate funds, while recognizing $0.1 million of acquisition related costs, which are included as part of general and administrative expenses in the Company’s consolidated statements of operations. The acquisition has been treated as a business combination and the total purchase price was allocated as follows: $36.0 million to building, $5.8 million to land, $6.5 million to intangible assets and $1.0 million to below market lease liabilities assumed. Six Tower Bridge On June 19, 2013, the Company acquired the remaining ownership interest in the real estate venture known as “Six Tower Bridge” that it did not then already own. See Note 4, “ Investments in Unconsolidated Real Estate Ventures, Cira Centre On November 19, 2013, the Company acquired a 0.8 acre land parcel underlying Cira Centre in Philadelphia, Pennsylvania for $24.6 million. The purchase terminates a long term ground lease agreement entered into during the development of Cira Centre. The Company has accounted for the transaction as an asset acquisition. Prior to the acquisition date, the Company recorded ground rent expense on a straight-line basis, resulting in accrued rent liability of $12.1 million. The accounting guidance for leases requires that an asset purchased which was previously subject to an operating lease cannot result in a gain, accordingly, the basis of the acquired land was reduced by the accrued rent liability and no income was recognized at acquisition. The Company capitalized $1.4 million of acquisition related costs as part of the basis in the operating land. Three Logan Square On April 25, 2013, the Company exercised its purchase option under the long term ground lease agreement it held through its acquisition of Three Logan Square on August 5, 2010 and acquired the 1.8 acre land parcel underlying Three Logan Square in Philadelphia, Pennsylvania for $20.8 million. The Company has accounted for the transaction as an asset acquisition. A portion of the original purchase price of Three Logan Square was allocated to a below market ground lease intangible asset. As the sum of the purchase price of the land plus the $4.3 million remaining unamortized balance for the intangible asset approximates the fair value of the land as unencumbered by the ground lease, the remaining intangible asset balance was reclassified to land upon exercise of the purchase option. The Company funded the cost of the acquisition with available corporate funds and capitalized $0.1 million of acquisition related costs as part of the basis in the operating land. Dispositions The Company sold the following office properties during the twelve-month period ended December 31, 2013 (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) December 19, 2013 875 First Avenue King of Prussia, PA 1 50,000 $ 3,750 $ 3,658 $ 131 October 17, 2013 1336 Enterprise Drive West Chester, PA 1 39,330 2,600 2,521 156 October 16, 2013 Austin Properties/DRA JV Austin, TX 7 1,398,826 330,000 266,340 25,864 (b) June 28, 2013 16870 West Bernardo Drive San Diego, CA 1 68,708 18,000 17,403 (856 ) June 28, 2013 100 Arrandale Boulevard Exton, PA 1 34,931 3,500 3,268 (401 ) June 19, 2013 1700 Paoli Pike (100 Applebrook) Malvern, PA 1 28,000 2,675 2,544 (444 ) June 14, 2013 Pacific View Plaza Carlsbad, CA 1 51,695 10,300 9,950 (521 ) February 25, 2013 Princeton Pike Corporate Center Lawrenceville, NJ 8 800,546 121,000 112,863 5,304 Total Dispositions 21 2,472,036 $ 491,825 $ 418,547 $ 29,233 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs. (b) The Austin portfolio was contributed to a newly formed real estate venture. For additional information, see Note 4, “ Investments in Unconsolidated Ventures On August 5, 2013, the Company sold an eight-acre parcel of land located in Richmond, Virginia known as Dabney Land East, for a sales price of $0.5 million resulting in a $0.1 million loss on sale after closing and other transaction related costs. The land parcel was undeveloped as of the date of sale. The sales of these properties, with the exception of the Austin portfolio and Dabney Land East, are included in discontinued operations.

Investment in Unconsolidated Ve

Investment in Unconsolidated Ventures	12 Months Ended
	Dec. 31, 2015
Equity Method Investments And Joint Ventures [Abstract]
INVESTMENT IN UNCONSOLIDATED VENTURES	4. INVESTMENT IN UNCONSOLIDATED VENTURES As of December 31, 2015, the Company held ownership interests in 16 unconsolidated Real Estate Ventures for an aggregate investment balance of $239.9 million, of which $241.0 million is included in assets and $1.1 million is included in other liabilities relating to the negative investment balance of one real estate venture. The Company formed or acquired interests in these ventures with unaffiliated 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, 2015, nine of the real estate ventures owned 31 office buildings that contain an aggregate of approximately 4.3 million net rentable square feet; two real estate ventures owned 4.3 acres of undeveloped parcels of land; three real estate ventures owned 2.2 acres of land under active development; one real estate venture owned a residential tower that contains 345 apartment units 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 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, 2015 and 2014, and the Company’s share of the Real Estate Ventures’ income (loss) for the years ended December 31, 2015 and 2014 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) 2015 2014 2015 2014 2015 2014 Current Interest Rate Debt Maturity Office Properties Brandywine-AI Venture LLC 50% $ 50,760 $ 45,712 $ (229 ) $ (185 ) $ 132,717 $ 133,843 3.94 % (c) DRA (G&I) Austin (b) 50% 60,427 40,374 (1,235 ) (574 ) 410,066 382,100 3.38 % (d) 1000 Chesterbrook Blvd. 50% 1,895 2,152 117 388 23,610 24,251 4.75 % Dec 2021 Four Tower Bridge 65% 1,684 1,474 211 (144 ) 10,162 10,353 5.20 % Feb 2021 PJP VII 25% 872 911 211 177 5,621 5,785 L+2.65% Dec 2019 PJP II 30% 435 403 32 73 3,201 3,492 6.12 % Nov 2023 PJP V 25% 305 216 189 166 5,035 5,242 6.47 % Aug 2019 PJP VI 25% 45 45 151 (67 ) 7,918 8,168 6.08 % Apr 2023 Invesco, L.P. (h) - - 349 989 - - Broadmoor Austin Associates (h) - 65,407 (377 ) (460 ) - 53,516 G&I Interchange Office LLC (DRA-N. PA) (h) - - - (658 ) - 174,595 Coppell Associates (e) 50% (1,130 ) (1,214 ) 84 (45 ) 15,515 15,747 5.75 % Feb 2016 Other HSRE-Campus Crest IX, LLC (b) 30% 15,003 14,314 (188 ) 67 95,562 90,245 L+2.20% Jul 2016 4040 Wilson 50% 36,626 27,415 (106 ) (132 ) - - TB-BDN Plymouth Apartments 50% 12,338 12,720 (252 ) (83 ) 50,964 29,481 L+1.70% Dec 2017 Residence Inn Tower Bridge (h) - 723 367 107 - 13,394 Development Properties Brandywine 1919 Ventures (b) (f) 50% 29,086 12,823 - (21 ) 19,411 - L+2.25% Oct 2018 51 N Street 70% 16,725 - - - - - 1250 First Street Office 70% 14,312 - - - - - Seven Tower Bridge 20% 491 315 (135 ) (388 ) 14,789 14,865 3.44 % (g) $ 239,874 $ 223,790 $ (811 ) $ (790 ) $ 794,571 $ 965,077 (a) Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable. (b) 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). (c) The debt for these properties is comprised of three fixed rate mortgages: (1) $38.8 million with a 4.40% fixed interest rate due January 1, 2019, (2) $27.6 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 3.94%. (d) The debt for these properties includes seven mortgages: (1) $34.0 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) $55.8 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) $140.3 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) $34.5 million with a 3.87% fixed interest rate due August 6, 2019, (6) $86.4 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 28, 2020, and (7) $30.0 million with a rate of LIBOR + 1.85% with a cap of 2.75%, resulting in a time and dollar weighted average rate of 3.38%. (e ) Carrying amount represents the negative investment balance of the venture and is included in other liabilities. ( f ) The stated rate for the construction loan is LIBOR + 2.25%. The interest rate spread decreases to 2.00% upon receipt of certificate of occupancy. It is further reduced to 1.75% upon stabilization. To fulfill interest rate protection requirements an interest rate cap was purchased at 4.50%. (g ) 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 $0.9 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, 2016 maturity and a $3.9 million 3.00% 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 3.4%. (h ) The ownership interest in Invesco, L.P. was sold prior to December 31, 2014. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in DRA-N. PA was disposed of on August 12, 2015. The following is a summary of the financial position of the Real Estate Ventures as of December 31, 2015 and December 31, 2014 (in thousands): December 31, 2015 December 31, 2014 Net property $ 1,258,999 $ 1,281,282 Other assets 158,672 195,121 Other liabilities 68,028 68,481 Debt 794,571 965,077 Equity 554,072 442,845 Company’s share of equity (Company’s basis) (a) (b) $ 241,004 $ 225,004 (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 and $1.2 million as of December 31, 2015 and 2014, respectively, which is included in other liabilities. The following is a summary of results of operations of the Real Estate Ventures in which the Company had interests as of December 31, 2015, 2014 and 2013 (in thousands): Years ended December 31, 2015 2014 2013 Revenue $ 164,928 $ 147,236 $ 102,919 Operating expenses (70,136 ) (61,268 ) (40,436 ) Interest expense, net (34,584 ) (36,511 ) (26,529 ) Depreciation and amortization (68,100 ) (57,109 ) (35,138 ) Net income (loss) $ (7,892 ) $ (7,652 ) $ 816 Company’s share of income (loss) (Company’s basis) $ (811 ) $ (790 ) $ 3,664 As of December 31, 2015, the aggregate principal payments of recourse and non-recourse debt payable to third-parties are as follows (in thousands): 2016 $ 120,811 2017 68,319 2018 244,403 2019 175,975 2020 92,761 Thereafter 92,302 $ 794,571 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," for further information. 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, 2015, the carrying value of the assets of 25 M Street was $20.5 million. 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 interest of the unaffiliated third party at fair value, which approximates carrying value. No remeasurement gain or loss on our 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, 2015, $19.4 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 cash contributions by DRA (less $1.9 million of closing costs and $6.9 million of closing prorations and lender holdbacks) to fund a $271.5 million distribution to the Company. The Company agreed to fund the first $5.2 million of post-closing capital expenditures on behalf of the Austin Venture, resulting in net proceeds of $266.3 million after funding the Company’s capital expenditure obligation. As part of the transaction, the Company’s subsidiary management company executed an agreement with the Austin Venture to provide property management and leasing services to the Austin Venture in exchange for a market-based fee. The Company measured its equity interest at fair value based on the fair value of the Austin Properties and the distribution provisions of the real estate venture agreement. Since the Company retains a non-controlling interest in the Austin Properties and there are no other facts and circumstances that preclude the consummation of a sale, the contribution qualifies as a partial sale of real estate under the relevant guidance for sales of real estate. Accordingly, during the fourth quarter of 2013, the Company recorded a gain of approximately $25.9 million, which is reflected in “Net gain (loss) on real estate venture transactions” on the accompanying statement of operations. On April 3, 2014, the Company contributed two three-story, Class A office buildings, commonly known as “Four Points Centre,” containing an aggregate of 192,396 net rentable square feet in Austin, Texas to the Austin Venture. See Note 3, “ Real Estate Investments On July 31, 2014, the Austin Venture acquired the Crossings at Lakeline, comprised of two three-story buildings containing an aggregate of 232,274 rentable square feet located in Austin, TX for $48.2 million. The transaction was funded with $34.5 million of proceeds of a 3.87% fixed rate mortgage loan from a non-affiliated institutional lender and $12.8 million (net of $0.9 million in purchase adjustments) of cash capital contributions, with $6.4 million made by each of DRA and the Company. The Austin Venture expensed approximately $0.1 million of transaction costs to acquire the property, net of $0.6 million credit from the seller. On October 17, 2014, the Austin Venture acquired River Place, comprised of seven Class A office buildings containing 590,881 rentable square feet located in Austin, Texas for $128.1 million. The transaction was funded through a combination of an $88.0 million short-term loan, secured by a mortgage, made by the Company to the Austin Venture and cash capital contributions of $18.9 million made by each of DRA and the Company to the Austin Venture. The short-term financing was provided by the Company while the Austin Venture secured permanent financing. As of December 31, 2014. The Company accounted the short-term financing as a note receivable. See Note 2, “ Summary of Significant Accounting Policies On January 30, 2015, the Austin Venture closed on a mortgage loan with a non-affiliated institutional lender, and used the proceeds of the loan to repay in full an $88.0 million short-term secured loan made by the Company to fund costs of the Austin Venture's acquisition of River Place. 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 the Austin Venture. See Note 3, “ Real Estate Investments Based upon the facts and circumstances at formation of the Austin Venture, the Company determined that the Austin Venture is not a VIE in accordance with the accounting standard for the consolidation of VIEs. As a result, the Company used the voting interest model under the accounting standard for consolidation in order to determine whether to consolidate the Austin Venture. Based upon each member’s substantive participating rights over the activities of the Austin Venture under the operating and related agreements of the Austin Venture, it is not consolidated by the Company, and is accounted for under the equity method of accounting. The reconsideration event caused by the Company’s contribution of Encino Trace to the Austin Venture did not change the conclusion reached at formation, as the Austin Venture is operating under the same operating and related agreements and the economics are unchanged. 4040 Wilson Venture On July 31, 2013, the Company formed 4040 Wilson LLC Venture (“4040 Wilson”), a joint venture between the Company and Ashton Park Associates LLC (“Ashton Park”), an unaffiliated third party. Each of the Company and Ashton Park owns a 50% interest in 4040 Wilson. 4040 Wilson expects to construct a 426,900 square foot office representing the final phase of the eight building, mixed-use, Liberty Center complex developed by the parent company of Ashton Park in the Ballston submarket of Arlington, Virginia. 4040 Wilson expects to develop the office building on a 1.3-acre land parcel contributed by Ashton Park to 4040 Wilson at an agreed upon value of $36.0 million. The total estimated project costs are $194.6 million, which the Company expects will be financed through approximately $72.0 million of partner capital contributions (consisting of $36.0 million in cash from the Company, of which $35.6 million has been funded to date, and land with a value of $36.0 million from Ashton Park), with the remaining balance funded by debt financing through a construction lender that has not yet been determined. During the second quarter of 2015, 4040 Wilson completed the construction of the garage structure. The Company expects groundbreaking on the building structure to commence upon achievement of certain pre-leasing levels, at which point 4040 Wilson expects to obtain debt financing for the remainder of the project costs. As of December 31, 2015, the Company had not provided any guarantees in respect of 4040 Wilson. Based upon the facts and circumstances at formation of 4040 Wilson, the Company determined that 4040 Wilson 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 4040 Wilson. Based upon each member’s shared power over the activities of 4040 Wilson under the operating and related agreements of 4040 Wilson, and the Company’s lack of control over the development and construction phases of the project, 4040 Wilson is not consolidated by the Company, and is accounted for under the equity method of accounting. Two and Six Tower Bridge Exchange Transaction On June 19, 2013, the Company acquired, from an unaffiliated third party, the third party’s ownership interest in the Six Tower Bridge real estate venture through a nonmonetary exchange for the Company’s ownership interest in the Two Tower Bridge real estate venture. The Six Tower Bridge real estate venture owns an unencumbered office property in Conshohocken, PA. The Company previously accounted for its noncontrolling interest in Six Tower Bridge using the equity method. As a result of the exchange transaction, the Company obtained control of the Six Tower Bridge property and the Company’s existing equity interest was remeasured at fair value based on the fair value of the underlying property and the distribution provisions of the real estate venture agreement. Accordingly, during 2013, the Company recorded a gain of approximately $7.8 million, which is reflected in “Net gain from remeasurement of investments in a real estate ventures” on the accompanying statement of operations. Following the acquisition, the Class A office property in Conshohocken, PA is wholly owned by the Company with an unencumbered fair value of $24.5 million. The Company accounted for this transaction as a business combination and allocated the fair value as follows: $14.8 million to building, $6.9 million to land, $3.3 million to intangible assets and $0.5 million to below market lease liabilities assumed. As mentioned above, the Company exchanged its non-controlling interest in Two Tower Bridge real estate venture in a nonmonetary transaction with an unaffiliated third party for the third party’s interest in the Six Tower Bridge real estate venture. The investment in Two Tower Bridge had a fair value of $3.6 million on the date of the exchange transaction based on the fair value of the venture’s equity and the distribution provisions of the real estate venture agreement. Based on this fair value and the carrying value for the Company’s investment of $(0.1) million, during 2013 the Company recognized a gain on exchange of interests in real estate ventures of $3.7 million, which is reflected in “Net gain (loss) on real estate venture transactions” on the accompanying statement of operations. 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. In connection with the development of evo at Cira, each of the Company and Campus Crest provided, in addition to customary non-recourse carve-out guarantees, a completion and cost overrun guaranty, as well as a payment guaranty, on the construction financing (with the Company’s share of the payment guaranty being approximately $24.7 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. Based upon the facts and circumstances at evo at Cira formation, the Company determined that evo at Cira 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 evo at Cira. Based upon each member’s shared power over the activities of evo at Cira under the operating and related agreements of evo at Cira, and the Company’s lack of exclusive control over the development and construction phases of the project, evo at Cira is not consolidated by the Company, and is accounted for under the equity method of accounting. Accordingly, the land parcel and associated development rights contributed by the Company to evo at Cira were deconsolidated by the Company upon formation of evo at Cira. During the third quarter of 2014, evo at Cira placed into service the student housing tower. BDN Beacon Venture On March 26, 2013, the Company sold its entire 20% ownership interest in an unconsolidated real estate venture known as BDN Beacon Venture LLC (the “Beacon Venture”). The carrying amount of the Company’s investment in the Beacon Venture amounted to $17.0 million at the sale date, with the Company’s proceeds effectively matching the carrying amount. Guarantees As of December 31, 2015, the Company had provided guarantees on behalf of certain real estate ventures, consisting of (i) a $24.7 million payment guarantee on the construction loan for evo at Cira; (ii) a $3.2 million payment guarantee on the construction loan for TB-BDN Plymouth Apartments; (iii) a several cost overrun guaranty on the $88.9 million construction loan for the development project being undertaken by 1919 Ventures; and (iv) a $0.5 million payment guarantee on a loan provided to PJP VII. In addition, during construction undertaken by real estate ventures, the Company has provided and expects to continue to provide cost overrun and completion guarantees, with rights of contribution among partners in the real estate ventures, as well as customary environmental indemnities and guarantees of customary exceptions to nonrecourse provisions in loan agreements.

Deferred Costs

Deferred Costs	12 Months Ended
	Dec. 31, 2015
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
DEFERRED COSTS	5. DEFERRED COSTS As of December 31, 2015 and 2014, the Company’s deferred costs (assets) were comprised of the following (in thousands): December 31, 2015 Total Cost Amortization Deferred Costs, net Leasing costs $ 165,741 $ (67,342 ) $ 98,399 Financing costs - Revolving Credit Facility (a) 3,578 (558 ) 3,020 Total $ 169,319 $ (67,900 ) $ 101,419 December 31, 2014 Total Cost Accumulated Amortization Deferred Costs, net Leasing costs $ 164,081 $ (64,065 ) $ 100,016 Financing costs - Revolving Credit Facility (a) 4,588 (3,343 ) 1,245 Total $ 168,669 $ (67,408 ) $ 101,261 (a) During the fourth quarter of 2015, the Company adopted accounting guidance related to the presentation of deferred financing costs on the balance sheet and reclassified amounts from the deferred costs line to net against the debt liability for all periods presented. Only deferred financing costs associated with our credit facility remain in deferred costs (assets) on the consolidated balance sheets. See Note 2, “ Summary of Significant Accounting Policies,” During the years ended December 31, 2015, 2014 and 2013, the Company capitalized internal direct leasing costs of $6.6 million, $7.1 million and $7.5 million, respectively, in accordance with the accounting standard for the capitalization of leasing costs.

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	6. INTANGIBLE ASSETS As of December 31, 2015 and 2014, the Company’s intangible assets were comprised of the following (in thousands): 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 December 31, 2014 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 129,411 $ (42,068 ) $ 87,343 Tenant relationship value 34,172 (26,344 ) 7,828 Above market leases acquired 5,641 (1,409 ) 4,232 Total intangible assets, net $ 169,224 $ (69,821 ) $ 99,403 Acquired lease intangibles, net: Below market leases acquired $ 53,049 $ (27,039 ) $ 26,010 For the years ended December 31, 2015, 2014, and 2013, the Company wrote-off through the acceleration of amortization approximately $0.5 million, $0.8 million and $1.6 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 2015, 2014 and 2013, the Company accelerated amortization of a nominal amount of intangible liabilities as a result of tenant move-outs. As of December 31, 2015, the Company’s annual amortization for its intangible assets/liabilities, assuming no early lease terminations, are as follows (in thousands): Assets Liabilities 2016 $ 36,635 $ 7,595 2017 19,814 3,461 2018 12,587 2,217 2019 11,288 1,885 2020 9,149 1,337 Thereafter 22,731 9,352 112,204 25,847 Assets held for sale (581 ) (192 ) Total $ 111,623 $ 25,655

Debt Obligations

Debt Obligations	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014 (in thousands): December 31, 2015 December 31, 2014 Effective Interest Rate Maturity Date MORTGAGE DEBT: Tysons Corner $ - $ 89,513 5.36 % Oct 2015 (a) Two Logan Square 86,886 87,767 7.57 % Apr 2016 Fairview Eleven Tower (b) 20,838 21,242 4.25 % Jan 2017 One Commerce Square 130,000 123,205 3.64 % (c) Apr 2023 Two Commerce Square 112,000 112,000 4.51 % (d) Apr 2023 IRS Philadelphia Campus (e) 177,425 184,442 7.00 % Sep 2030 Cira South Garage (e) 35,546 37,765 7.12 % Sep 2030 Principal balance outstanding 562,695 655,934 Plus: fair market value premium (discount), net (3,198 ) (1,344 ) Less: deferred financing costs (13,744 ) (14,959 ) Mortgage indebtedness $ 545,753 $ 639,631 UNSECURED DEBT Seven-Year Term Loan - Swapped to fixed $ 250,000 $ 200,000 3.72 % (f) Oct 2022 $250.0M 6.00% Guaranteed Notes due 2016 149,919 149,919 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 1,853,529 1,803,529 Plus: original issue premium (discount), net (5,714 ) (6,811 ) Less: deferred financing costs (8,851 ) (9,004 ) Total unsecured indebtedness $ 1,838,964 $ 1,787,714 Total Debt Obligations $ 2,384,717 $ 2,427,345 ( a ) On August 19, 2015, the Company entered into a forbearance agreement to extend the maturity date of the mortgage note payable collateralized by two of its properties located at 8260 Greensboro Drive and 1676 International Drive in Mclean, Virginia (referred to as "Tysons Corner" above). On October 9, 2015, the Company funded $88.4 million, including $0.4 million of accrued interest, in repayment of the Tysons Corner mortgage note with funds from the additional borrowings under the seven-year term loan referenced below. (b ) Represents the full debt amount of a property in a consolidated real estate venture for which the Company maintains a 50% interest. ( 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 ) Mortgage debt was prepaid prior to the scheduled maturity. See Note 21, “Subsequent Events,” ( f ) 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 will bear 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%. During the fourth quarter of 2015, the Company adopted accounting guidance related to the presentation of deferred financing costs on the balance sheet and reclassified amounts from the deferred costs line to net against the liability for all periods presented. Deferred financing costs associated with our credit facility remain in deferred costs on the consolidated balance sheet. See Note 2, “Summary of Significant Accounting Policies,” During 2015, 2014, and 2013, the Company’s weighted-average effective interest rate on its mortgage notes payable was 5.72%, 5.72%, and 5.73%, respectively. As of December 31, 2015 and 2014, the net carrying value of the Company’s Properties that are encumbered by mortgage indebtedness was $562.7 million and $655.9 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 2024 Notes and 2029 Notes (as defined above). 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 $1.3 million and $1.8 million, respectively, in the consolidated balance sheets as of December 31, 2015 and $1.5 million and $2.0 million, respectively, in the consolidated balance sheets as of December 31, 2014. 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, 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) Gain (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 During the year-ended December 31, 2013, the Company repurchased $29.3 million of its outstanding unsecured Notes in a series of transactions that are summarized in the following table (in thousands): Notes Principal Repurchase Amount (a) Gain (Loss) on Early Extinguishment of Debt (b) Acceleration of Deferred Financing 2014 5.40% Notes $ 19,830 $ 20,853 $ (1,020 ) $ 16 2015 7.50% Notes 8,910 9,945 (1,036 ) 23 2016 6.00% Notes 510 571 (63 ) 1 $ 29,250 $ 31,369 $ (2,119 ) $ 40 (a) Includes cash losses with respect to redemption of debt. (b) Includes unamortized balance of the original issue discount. On May 15, 2015, the Company closed on a new four-year unsecured revolving credit facility (the "New Credit Facility") that provides for borrowings of up to $600.0 million. The Company expects to use advances under the New 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 New 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 New 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 New 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 New 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 New Credit Facility as of December 31, 2015. The New Credit Facility contains financial and operating covenants and restrictions, including covenants that relate to our 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 New 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 New 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, 2015, the Company was in compliance with all covenants in the New Credit Facility. Concurrently with its entry into the New Credit Facility, the Company terminated its then existing unsecured revolving credit facility, which had a scheduled maturity date of February 1, 2016. As amended, Term Loan C contains financial and operating covenants and restrictions, including covenants that relate to the incurrence of additional debt; the granting of liens; the 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. The restriction on dividends permits the Company to pay dividends to the greater of (i) an amount required for the Company to retain its qualification as a REIT and (ii) 95% of its funds from operations. The term loan includes financial covenants that require the Company to maintain an interest coverage ratio, a fixed charge coverage ratio and an unencumbered cash flow ratio above specified levels; to maintain a minimum net worth above an amount determined on a specified formula; and to maintain a leverage ratio and a secured debt ratio below certain maximum levels. Another financial covenant limits the ratio of unsecured debt to the value of unencumbered properties As of December 31, 2015, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2016 $ 249,468 2017 333,682 2018 340,437 2019 16,768 2020 17,661 Thereafter 1,458,208 Total principal payments 2,416,224 Net unamortized premiums/(discounts) (8,912 ) Net deferred financing costs (22,595 ) Outstanding indebtedness $ 2,384,717

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014, 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, 2015 and 2014 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, 2015 December 31, 2014 Carrying Amount Fair Value Carrying Amount Fair Value Unsecured notes payable $ 1,512,554 $ 1,529,346 $ 1,510,181 $ 1,593,212 Variable rate debt $ 326,410 $ 305,522 $ 277,533 $ 257,188 Mortgage notes payable (a) $ 545,753 $ 597,377 $ 639,631 $ 707,241 Mortgage note receivable (b) $ - $ - $ 88,000 $ 87,692 (a) The IRS Philadelphia Campus mortgage debt and Cira South Garage mortgage debt were prepaid prior to their scheduled maturity. See Note 21, “Subsequent Events,” (b) See Note 2, “ Summary of Significant Accounting Policies - Notes Receivable The fair value of the Company’s unsecured notes payable is categorized at a Level 2 basis (as provided by the accounting standard for Fair Value Measurements and Disclosures). This is because the Company valued these instruments using quoted market prices as of December 31, 2015 and 2014. 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 fair value of the Company’s mortgage notes payable, variable rate debt and notes receivable are all categorized at a Level 3 basis (as provided by the accounting standard for Fair Value Measurements and Disclosures). 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. The fair value of the notes receivable was determined by using the expected cash flows of the notes receivable, and discounting those cash flows using the market rate of interest for mortgage notes with a comparable level of risk. These financial instruments 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 on its knowledge of the mortgage market. The weighted average discount rate for the combined variable rate debt and mortgage loans used as to calculate fair value as of December 31, 2015 was 4.550%. 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, 2015 and December 31, 2014. 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, 2015, and current estimates of fair value may differ from the amounts presented herein.

Risk Management and Use of Fina

Risk Management and Use of Financial Instruments	12 Months Ended
	Dec. 31, 2015
Derivative Instruments And Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND USE OF FINANCIAL INSTRUMENTS	9. RISK MANAGEMENT AND USE OF 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 2016 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, 2015. 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. 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, 2015 and December 31, 2014. 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 liabilities on the Company’s consolidated balance sheets). Hedge Product Hedge Type Designation Notional Amount Strike Trade Date Maturity Date Fair value 12/31/2015 12/31/2014 12/31/2015 12/31/2014 Assets Swap Interest Rate Cash Flow (a), (b) $ 250,000 $ - 3.718 % October 8, 2015 October 8, 2022 $ 1,884 $ - Liabilities Swap Interest Rate Cash Flow (a), (b) $ - $ 200,000 3.623 % December 6-13, 2011 February 1, 2019 $ - $ (2,649 ) Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 (531 ) (334 ) Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 (388 ) (254 ) Swap Interest Rate Cash Flow (a) 27,062 27,062 2.750 % December 21, 2011 September 30, 2017 (201 ) (253 ) $ 328,610 $ 278,610 (a) Hedging unsecured variable rate debt. (b) On October 8, 2015, the Company amended its $200.0 million seven-year term loan maturing February 1, 2019, increasing the term loan by an additional $50.0 million and lengthening the maturity date to October 8, 2022 (See Note 7, “ Debt Obligations 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, 2015, one interest rate swap held a 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 its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. 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 2015, 2014 and 2013. 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, 2015
Discontinued Operations And Disposal Groups [Abstract]
DISCONTINUED OPERATIONS	10. DISCONTINUED OPERATIONS The Company had no property dispositions classified as discontinued operations during the year ended December 31, 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 completed in the first quarter of 2013. For the years ended December 31, 2014 and 2013, income from discontinued operations relates to an aggregate of 14 properties containing approximately 1.1 million net rentable square feet that the Company has sold since January 1, 2013. The following table summarizes revenue and expense information for the properties sold which qualify for discontinued operations reporting since January 1, 2013 (in thousands): Years ended December 31, 2014 2013 Revenue: Rents $ - $ 4,754 Tenant reimbursements 26 355 Other - 123 Total revenue 26 5,232 Expenses: Property operating expenses 8 1,839 Real estate taxes - 649 Depreciation and amortization - 1,921 Total operating expenses 8 4,409 Other income: Interest income - 2 Income from discontinued operations before gain on sale of interests in real estate 18 825 Net gain on disposition of discontinued operations 900 3,382 Income from discontinued operations $ 918 $ 4,207 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, 2015
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, 2015 and December 31, 2014, was $16.1 million and $17.5 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 $21.0 million and $24.5 million, respectively, as of December 31, 2015 and December 31, 2014.

Beneficiaries Equity of the Par

Beneficiaries Equity of the Parent Company	12 Months Ended
	Dec. 31, 2015
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, 2015 2014 2013 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 $ 38,982 $ 38,982 Net income (loss) from continuing operations attributable to non-controlling interests 339 339 43 43 (357 ) (357 ) Nonforfeitable dividends allocated to unvested restricted shareholders (329 ) (329 ) (349 ) (349 ) (363 ) (363 ) Preferred share dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Income (loss) from continuing operations available to common shareholders (37,630 ) (37,630 ) (1,182 ) (1,182 ) 31,362 31,362 Income from discontinued operations - - 908 908 4,152 4,152 Net income (loss) attributable to common shareholders $ (37,630 ) $ (37,630 ) $ (274 ) $ (274 ) $ 35,514 $ 35,514 Denominator Weighted-average shares outstanding 178,162,160 178,162,160 166,202,649 166,202,649 153,140,458 153,140,458 Contingent securities/Share based compensation - - - - - 1,273,853 Weighted-average shares outstanding 178,162,160 178,162,160 166,202,649 166,202,649 153,140,458 154,414,311 Earnings (loss) per Common Share: Income (loss) from continuing operations attributable to common shareholders $ (0.21 ) $ (0.21 ) $ (0.01 ) $ (0.01 ) $ 0.20 $ 0.20 Discontinued operations attributable to common shareholders - - 0.01 0.01 0.03 0.03 Net income (loss) attributable to common shareholders $ (0.21 ) $ (0.21 ) $ - $ - $ 0.23 $ 0.23 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 1,535,102 in both 2015 and 2014 and 1,763,739 in 2013, 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, 2015, 2014 and 2013, earnings representing nonforfeitable dividends were allocated to the unvested restricted shares issued to the Company’s executives and other employees under the 1997 Plan. Common and Preferred Shares On December 8, 2015, the Parent Company declared a distribution of $0.15 per common share, totaling $26.5 million, which was paid on January 20, 2016 to shareholders of record as of January 6, 2016. On December 8, 2015, the Parent Company declared distributions on its Series E Preferred Shares to holders of record as of December 30, 2015. 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 15, 2016 to holders of Series E Preferred Shares totaled $1.7 million. On August 1, 2014, the Parent Company completed an underwritten offering of 21,850,000 common shares. The Parent Company contributed the net proceeds from the sale of the common shares, amounting to $335.0 million after deducting underwriting discounts and commissions and other offering expenses, to the Operating Partnership in exchange for partnership units of the Operating Partnership. The Operating Partnership intends to use the net proceeds for working capital, capital expenditures and other general corporate purposes, which may include acquisitions, developments and the repayment, repurchase and refinancing of debt. On November 5, 2013, the Parent Company commenced a continuous equity offering program (the “Offering Program”), under which it may sell, in at-the-market offerings, up to an aggregate amount of 16,000,000 common shares until November 5, 2016. This Offering Program replaced a prior continuous equity offering program which expired on March 10, 2013. The Parent Company may sell common shares in amounts and at times to be determined by the Parent Company. Actual sales will depend on a variety of factors to be determined by the Parent Company, including, among others, market conditions, the trading price of the Company’s common shares of beneficial interest and determinations by the Parent Company of the appropriate sources of funding. In conjunction with the Offering Program, the Parent Company engages sales agents who receive compensation, in aggregate, of up to 2% of the gross sales price per share sold. From inception of the Offering Program through December 31, 2015, the Parent Company has not sold any shares under the program, resulting in 16,000,000 remaining shares available for sale. On April 10, 2013, the Parent Company closed a public offering of 12,650,000 common shares, inclusive of 1,650,000 common shares issued upon exercise by the underwriters of the option granted to them to purchase additional shares. The Parent Company contributed the net proceeds from the sale of shares, amounting to $181.5 million after deducting underwriting discounts and commissions and other offering expenses, to the Operating Partnership in exchange for partnership units of the Operating Partnership. The Operating Partnership continues to use the net proceeds for working capital, capital expenditures and other general corporate purposes, which may include acquisitions, developments and the repayment, repurchase and refinancing of debt. Common Share Repurchases The Parent Company maintains a share repurchase program under which the Board of Trustees has authorized the Parent Company to repurchase shares of its preferred and common stock with no expiration date. On July 22, 2015, the Parent Company's Board of Trustees authorized additional 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 our line of credit. As of December 31, 2015, 5,209,437 common shares have been repurchased and retired at an average purchase price of $12.90 per share and totaling $67.3 million. 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 our 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 stock repurchases 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 stock (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, 2015
Equity [Abstract]
Partners Equity Of Operating Partnership Text Block	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, 2015 2014 2013 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 $ 38,982 $ 38,982 Nonforfeitable dividends allocated to unvested restricted unitholders (329 ) (329 ) (349 ) (349 ) (363 ) (363 ) Preferred unit dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Net loss attributable to non-controlling interests 3 3 44 44 - - Income (loss) from continuing operations available to common unitholders (37,966 ) (37,966 ) (1,181 ) (1,181 ) 31,719 31,719 Discontinued operations attributable to common unitholders - - 918 918 4,207 4,207 Net income (loss) attributable to common unitholders $ (37,966 ) $ (37,966 ) $ (263 ) $ (263 ) $ 35,926 $ 35,926 Denominator Weighted-average units outstanding 179,697,262 179,697,262 167,942,246 167,942,246 154,929,545 154,929,545 Contingent securities/Share based compensation - - - - - 1,273,853 Total weighted-average units outstanding 179,697,262 179,697,262 167,942,246 167,942,246 154,929,545 156,203,398 Earnings (loss) per Common Partnership Unit: Income (loss) from continuing operations attributable to common unitholders (0.21 ) (0.21 ) (0.01 ) (0.01 ) 0.20 0.20 Discontinued operations attributable to common unitholders - - 0.01 0.01 0.03 0.03 Net income (loss) attributable to common unitholders $ (0.21 ) $ (0.21 ) $ - $ - $ 0.23 $ 0.23 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, 2015, 2014 and 2013, 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, 2015, 2014 and 2013, which was $13.66, $15.98, $14.09, respectively. As of December 31, 2015 and 2014, 1,535,102 of Class A Units were outstanding and owned by outside limited partners of the Operating Partnership. As of December 31, 2013, 1,763,739 of Class A Units were outstanding and owned by outside limited partners of the Operating Partnership. On December 8, 2015, the Operating Partnership declared a distribution of $0.15 per common unit, totaling $26.5 million, which was paid on January 20, 2016 to unitholders of record as of January 6, 2016. On December 8, 2015, the Operating Partnership declared distributions on its Series E Preferred Units to holders of record as of December 30, 2015. 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 15, 2016 to holders of Series E Preferred Shares totaled $1.7 million. On November 5, 2013, the Parent Company commenced a continuous equity offering program (the “Offering Program”), under which it may sell, in at-the-market offerings, up to an aggregate amount of 16,000,000 common shares until November 5, 2016. This Offering Program replaced a prior continuous equity offering program which expired on March 10, 2013. The Parent Company may sell common shares in amounts and at times to be determined by the Parent Company. Actual sales will depend on a variety of factors to be determined by the Parent Company, including, among others, market conditions, the trading price of the Company’s common shares of beneficial interest and determinations by the Parent Company of the appropriate sources of funding. In conjunction with the Offering Program, the Parent Company engages sales agents who receive compensation, in aggregate, of up to 2% of the gross sales price per share sold. From inception of the Offering Program through December 31, 2015 the Parent Company has not sold any shares under the program, resulting in 16,000,000 remaining shares available for sale. Generally, the Parent Company contributes the net proceeds from the sales to the Operating Partnership, which the Operating Partnership in turn uses for general corporate purposes. Common Unit Repurchases The Parent Company maintains a share repurchase program under which the Board of Trustees has authorized the Parent Company to repurchase shares of its preferred and common stock with no expiration date. On July 22, 2015, the Parent Company's Board of Trustees authorized additional 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 our line of credit. As of December 31, 2015, 5,209,437 common shares have been repurchased and retired at an average purchase price of $12.90 per share and totaling $67.3 million. 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 our 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 stock repurchases 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 stock (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, 2015
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, 2015, options exercisable for 2,624,067 common shares were outstanding under the Parent Company’s shareholder approved equity incentive plan (referred to as the “Equity Incentive Plan”). During the year ended December 31, 2015, the Company did not recognize any compensation expense related to unvested options. During the year ended December 31, 2014, the Company recognized compensation expense related to unvested options that was nominal. For the year ended 2013, the Company recognized compensation expense related to unvested options of $0.7 million. During the year ended December 31, 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 years ended December 31, 2014 and 2013, the Company capitalized a nominal amount and $0.1 million, respectively. Option activity as of December 31, 2015 and changes during the year-ended December 31, 2015 were as follows: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2015 2,684,795 $ 15.55 4.10 Exercised (10,728 ) $ 11.89 $ 18,989 Forfeited/Expired (50,000 ) $ 20.61 Outstanding at December 31, 2015 2,624,067 $ 15.47 3.12 - Vested/Exercisable at December 31, 2015 2,624,067 $ 15.47 3.12 - 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. Employees automatically vest in employer contributions. Beginning in 2016, the Company will begin funding its 401(k) contributions annually and plan participants must be employed as of December 31 st Restricted Share Awards As of December 31, 2015, 506,147 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, 2015 was approximately $2.4 million, and is expected to be recognized over a weighted average remaining vesting period of 1.6 years. During 2015, the Company recognized compensation expense related to outstanding restricted shares of $2.4 million, of which $0.7 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. For the years ended December 31, 2014 and 2013, the Company recognized $2.7 million (of which $0.6 million was capitalized) and $3.2 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, 2015: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2015 540,066 $ 12.21 Granted 186,791 15.67 $ 2,927,538 Vested (219,312 ) 11.78 $ 3,272,381 Forfeited (1,398 ) 14.33 Non-vested at December 31, 2015 506,147 $ 14.50 $ 6,913,968 On February 23, 2015 and March 10, 2015, the Compensation Committee of the Parent Company’s Board of Trustees awarded restricted shares, of which 119,136 cliff vest after three years from the grant date 33,649 vest ratably over two years. On May 28, 2015, which vest ratably over three years. Restricted shares that cliff vest are subject to acceleration upon a change in control or 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 accordance with the accounting standard for stock-based compensation, the Company amortizes stock-based compensation costs through the qualifying retirement dates for those executives who meet the conditions for qualifying retirement during the scheduled vesting period. 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 2/25/2013 3/11/2014 3/12/2014 2/23/2015 Total (Amounts below in shares, unless otherwise noted) Non-vested at January 1, 2015 199,577 130,717 61,720 - 392,014 Units Granted - - - 186,395 186,395 Units Accelerated for Qualifying Retirement (8,255 ) (7,562 ) - (7,003 ) (22,820 ) Non-vested at December 31, 2015 191,322 123,155 61,720 179,392 555,589 Measurement Period Commencement Date 1/1/2013 1/1/2014 1/1/2014 1/1/2015 Measurement Period End Date 12/31/2015 12/31/2016 12/31/2016 12/31/2017 Units Granted 231,093 134,284 61,720 186,395 Fair Value of Units on Grant Date (in thousands) $ 4,137 $ 2,624 $ 1,225 $ 3,933 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 stock-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, 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. For the year ended December 31, 2013, the Company recognized total compensation expense for the 2013, 2012 and 2011 RPSU awards of $4.4 million, of which $0.8 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, 2015 was approximately $2.0 million, and is expected to be recognized over a weighted average remaining vesting period of 1.0 year. The Company issued 486,056 common shares on February 1, 2015 in settlement of RPSUs that had been awarded on March 1, 2012 (with a three-year measurement period ended December 31, 2014). Holders of these RPSUs also received a cash dividend of $0.15 per share for these common shares on February 6, 2015. 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 2015 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, 2015, employees made purchases under the ESPP of $0.5 million and the Company recognized $0.1 million of compensation expense related to the ESPP. During the years ended December 31, 2014 and 2013, employees made purchases under the ESPP of $0.4 million and the Company recognized $0.1 million of compensation expense related to the ESPP. 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, 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. For the year ended December 31, 2013, the Company recorded a net increase in compensation costs of $0.2 million, 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, 2015 and 2014, 0.7 million and 0.4 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, 2015
Distributions [Abstract]
Distributions	15. DISTRIBUTIONS The following table provides the tax characteristics of the 2015, 2014 and 2013 distributions: Years ended December 31, 2015 2014 2013 (in thousands, except per share amounts) Common Share Distributions: Ordinary income $ 0.36 $ 0.41 $ 0.52 Capital gain 0.14 0.02 - Non-taxable distributions 0.10 0.17 0.08 Distributions per share $ 0.60 $ 0.60 $ 0.60 Percentage classified as ordinary income 59.10 % 69.00 % 87.00 % Percentage classified as capital gain 23.50 % 3.30 % -% Percentage classified as non-taxable distribution 17.40 % 27.70 % 13.00 % Preferred Share Distributions: Total distributions declared $ 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, 2015
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 is entitled to substantially all of the benefits derived from the tax rehabilitation credits available under section 47 of the Internal Revenue Code. USB does not have a material interest in the underlying economics of the property. This transaction includes a put/call provision whereby the Company may be 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 obligate the Company to deliver tax benefits and provide other guarantees to USB and that entitle 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, are consideration that the Company receives 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 will be recognized as revenue in the consolidated financial statements beginning when the obligation to USB is relieved which occurs 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, 2015, there were no USB contributions presented in the Company’s balance sheet. As of December 31, 2014 there were $15.1 million total USB contributions presented in the Company's balance sheet. The contributions were recorded net of the amounts allocated to non-controlling interest for 2014, as described above of $3.0 million at year end December 31, 2014, with the remaining balance presented within deferred income. Direct and incremental costs incurred in structuring the transaction are deferred and will be 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, 2015. At December 31, 2014, there were $0.5 million of deferred costs recognized and included in other assets in the Company’s consolidated balance sheet. 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 and $1.4 million for each of the years ended December 31, 2014 and 2013. 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 expects to receive 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, 2015. At December 31, 2014, the total USB contributions presented in the Company’s balance sheet were $13.0 million. 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, 2015
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, 2015 (in thousands): Parent Company Cash Flow Hedges Balance at January 1, 2013 $ (15,918 ) Change during year 12,789 Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests (152 ) Reclassification adjustments for (gains)/losses reclassified into operations 286 Balance at December 31, 2013 $ (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 ) Operating Partnership Cash Flow Hedges Balance at January 1, 2013 $ (16,452 ) Change during year 12,789 Reclassification adjustments for (gains)/losses reclassified into operations 286 Balance at December 31, 2013 $ (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 ) 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 balance1 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 $1.1 million from AOCI into interest expense within the next twelve months.

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2015
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. The Pennsylvania 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 New Jersey/Delaware segment includes properties in Burlington and Camden counties in New Jersey and in New Castle county in the state of Delaware. The Richmond, Virginia segment includes properties primarily in Albemarle, Chesterfield, Goochland and Henrico counties and one property in Durham, North Carolina. The Austin, Texas segment includes properties in the City of Austin, Texas. The California segment includes properties in Oakland and Concord, California. 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, 2015, 2014 and 2013 (in thousands): Real estate investments, at cost: December 31, 2015 December 31, 2014 December 31, 2013 Philadelphia CBD (a) $ 1,157,667 $ 1,338,655 $ 1,300,666 Pennsylvania Suburbs (b) 1,019,280 1,178,470 1,199,105 Metropolitan Washington, D.C. (b) 1,129,206 1,183,652 1,214,965 New Jersey/Delaware (b) 154,326 392,581 414,716 Richmond, Virginia (b) - 317,076 310,397 California 68,003 193,258 192,584 Austin, Texas (c) 164,518 - 36,856 $ 3,693,000 $ 4,603,692 $ 4,669,289 Assets held for sale (a), (b) 794,588 27,436 - Operating Properties $ 4,487,588 $ 4,631,128 $ 4,669,289 Corporate Construction-in-progress $ 268,983 $ 201,360 $ 74,174 Land inventory $ 130,479 $ 90,603 $ 93,351 ( a) 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. ( b ) As of December 31, 2015, the 58 properties associated with the transaction 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 21, “Subsequent Events,” The sale is not classified as a significant disposition under the accounting guidance for discontinued operations ( c ) 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, 2015. See Note 3, "Real Estate Investments," Years ended December 31, 2015 2014 2013 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 $ 209,298 $ (77,352 ) $ 131,946 $ 201,809 $ (75,262 ) $ 126,547 $ 146,081 $ (55,702 ) $ 90,379 Pennsylvania Suburbs 158,398 (57,319 ) 101,079 160,630 (55,062 ) 105,568 153,426 (54,506 ) 98,920 Metropolitan Washington, D.C. 110,657 (44,294 ) 66,363 113,834 (43,399 ) 70,435 116,048 (42,641 ) 73,407 New Jersey/Delaware 47,726 (26,854 ) 20,872 60,403 (31,650 ) 28,753 60,262 (29,981 ) 30,281 Richmond, Virginia 36,486 (15,073 ) 21,413 34,180 (15,399 ) 18,781 35,058 (14,916 ) 20,142 California 14,587 (7,677 ) 6,910 19,388 (10,165 ) 9,223 18,369 (9,411 ) 8,958 Austin, Texas (b) 20,910 (8,010 ) 12,900 5,610 (3,223 ) 2,387 31,451 (13,298 ) 18,153 Corporate 4,569 (1,508 ) 3,061 1,128 (1,805 ) (677 ) 1,515 (1,314 ) 201 Operating Properties $ 602,631 $ (238,087 ) $ 364,544 $ 596,982 $ (235,965 ) $ 361,017 $ 562,210 $ (221,769 ) $ 340,441 (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, 2015. See Note 3, "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, 2015 December 31, 2014 December 31, 2013 2015 2014 2013 Philadelphia CBD (a) $ 44,089 $ 27,137 $ 19,975 $ (188 ) $ 46 $ 1,547 Pennsylvania Suburbs 16,408 17,385 17,272 310 (777 ) 925 Metropolitan Washington, D.C. (b) 118,422 73,127 59,905 (336 ) (317 ) 130 New Jersey/Delaware - - - 348 989 1,245 Richmond, Virginia 1,657 1,574 1,400 582 349 381 Austin, Texas (c) (d) 60,428 105,781 81,960 (1,527 ) (1,080 ) (564 ) Total $ 241,004 $ 225,004 $ 180,512 $ (811 ) $ (790 ) $ 3,664 (a) evo at Cira was placed into service during the third quarter ended September 30, 2014. (b) Investment in real estate ventures as of December 31, 2015 includes the JBG Ventures, which were formed on May 29, 2015. (c) Investment in real estate ventures does not include the $1.1 million and $1.2 million negative investment balance in one real estate venture as of December 31, 2015 and December 31, 2014, respectively, which is included in other liabilities. ( d ) On June 22, 2015 the Company acquired the remaining 50.0% of the common interest in Broadmoor Austin Associates. As such, the equity method investment at December 31, 2015 related to the Austin Venture only. See Note 3, " Real Estate Investments ," for further information regarding the purchase of Broadmoor Austin Associates. 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. 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, as defined by GAAP: Years Ended December 31, 2015 2014 2013 Consolidated net operating income $ 364,544 $ 361,017 $ 340,441 Less: Interest expense (110,717 ) (124,329 ) (121,937 ) Interest expense - amortization of deferred financing costs (4,557 ) (5,148 ) (4,676 ) Interest expense - financing obligation (1,237 ) (1,144 ) (972 ) Depreciation and amortization (219,029 ) (208,569 ) (197,021 ) General and administrative expenses (29,406 ) (26,779 ) (27,628 ) Equity in income (loss) of real estate ventures (811 ) (790 ) 3,664 Provision for impairment (82,208 ) (1,765 ) - Plus: Interest income 1,224 3,974 1,044 Tax credit transaction income 19,955 11,853 11,853 Recognized hedge activity - (828 ) - Net gain from remeasurement of investments in real estate ventures 758 458 6,866 Net gain on sales of interests in real estate 20,496 4,901 - Net gain (loss) on sale of undepreciated real estate 3,019 1,184 (137 ) Net gain (loss) on real estate venture transactions 7,229 (417 ) 29,604 Loss on early extinguishment of debt - (7,594 ) (2,119 ) Income (loss) from continuing operations (30,740 ) 6,024 38,982 Income from discontinued operations - 918 4,207 Net income (loss) $ (30,740 ) $ 6,942 $ 43,189

Operating Leases

Operating Leases	12 Months Ended
	Dec. 31, 2015
Leases Operating [Abstract]
OPERATING LEASES	19. OPERATING LEASES The Company leases properties to tenants under operating leases with various expiration dates extending to 2030. Minimum future rentals on non-cancelable leases at December 31, 2015 are as follows (in thousands): Year Minimum Rent 2016 $ 448,798 2017 425,828 2018 394,055 2019 349,315 2020 307,163 Thereafter 1,500,760 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, 2015
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 we determine 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 December 31, 2015. There were no mortgage lenders with letters of credit at December 31, 2014. 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 5 to 73 years. Minimum future rental payments on non-cancelable leases at December 31, 2015 are as follows (in thousands): Year Minimum Rent 2016 $ 1,385 2017 1,385 2018 1,385 2019 1,385 2020 1,385 Thereafter 67,229 Total $ 74,154 The Company obtained ground tenancy rights related to two 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. Other Commitments or Contingencies 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, September 2019. 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 September 2019. As of December 31, 2015, the Company had a balance of $2.0 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, 2015: 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. The Company’s agreements generally provide that it may dispose of the subject properties only in transactions that qualify as tax-free exchanges under Section 1031 of the Internal Revenue Code or in other tax deferred transactions. If the Company were to sell a restricted property before expiration of the restricted period in a non-exempt transaction, the Company may be required to make significant payments to the parties who sold the applicable property on account of tax liabilities attributed to them. Similarly, as part of the 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 not sell these two properties in certain taxable transactions prior to October 20, 2021 without the holder’s consent. 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. In connection with the development of the IRS Philadelphia Campus and the Cira South Garage, during 2008, the Company entered into a historic tax credit and new markets tax credit arrangement, respectively. The Company is required to be in compliance with various laws, regulations and contractual provisions that apply to its historic and new market tax credit arrangements. Non-compliance with applicable requirements could result in projected tax benefits not being realized and therefore, require a refund to US Bancorp or a reduction of investor capital contributions, which are reported as deferred income in the Company’s consolidated balance sheet, until such time as its obligation to deliver tax benefits is relieved. The remaining compliance periods for its tax credit arrangements expired on December 30, 2015. The Company does not anticipate that any material refunds or reductions of investor capital contributions will be required in connection with these arrangements. 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 $77.3 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. The Company invests in its properties and regularly incurs capital expenditures in the ordinary course 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, 2015
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	21. SUBSEQUENT EVENTS 30 th On February 5, 2016, the Company completed the disposition of its equity interests in the office property located at 2970 Market Street in Philadelphia, Pennsylvania commonly known as 30 th for a gross sales price of $354.0 million. Cira Square, which contains 862,692 net rentable square feet of office space and is fully leased to a single tenant, was encumbered by mortgage indebtedness at December 31, 2015 (referred to in Note 7, “Debt Obligations,” as IRS Philadelphia Campus – Mortgage Debt) On January 14, 2016, the Company funded $221.4 million, consisting of $176.8 million of principal repayment, $44.5 million in prepayment charges and $0.1 million of accrued interest, in repayment of the mortgage indebtedness of Cira Square, ahead of its scheduled maturity date of September 10, 2030. Also on January 14, 2016, the Company funded $44.5 million, consisting of $35.4 million of principal repayment, $8.9 million in prepayment charges and a nominal amount of accrued interest, in repayment of the mortgage indebtedness of the Cira South Garage, ahead of its scheduled maturity date of September 10, 2030. The repayment was financed with funds available under the unsecured revolving credit facility. Additionally, the Company recognized a loss on extinguishment of debt in the amount of $13.2 million related to a non-cash charge for deferred financing costs. The Company intends to use the net proceeds from the Cira Square sale, net of the early mortgage payoffs, to reduce debt, fund current development commitments and for general corporate purposes. The transaction agreements provide for the purchaser to engage the Company’s management company subsidiary to provide customary property management services for the property with an annual management fee (exclusive of expense reimbursement) not to exceed 1.5% of annual gross revenues of the property. The Company’s agreement is for a ten-year term, subject to early termination by the purchaser in the event that the Company fails to fulfill its obligations at any time during the term of the agreement or upon sale by the purchaser of the property. If the purchaser terminates the agreement within seven years of the management agreement commencement date the Company shall be entitled to a termination fee in an amount equal to the management fee that would have been paid to the Company for the remainder of the seven-year term had such termination not occurred. Och Ziff Sale On February 4, 2016, the Company received $353.4 million in cash proceeds from a series of related transactions with affiliates of Och Ziff Capital Management Group LLC (“Och Ziff”) that resulted in the disposition of 58 properties that contain an aggregate of 3,924,783 square feet. The properties are located in the Pennsylvania Suburbs, New Jersey/Delaware, Metropolitan Washington, D.C. and Richmond, Virginia segments. The transactions involved: (i) the sale to MAP Fee Owner LLC, an affiliate of Och-Ziff (the “O-Z Land Purchaser”), 100% of the Company’s fee interests in the land parcels (the “Land Parcels”) underlying the office properties, together with rights to be the lessor under long-term ground leases (the “Ground Leases”) covering the Land Parcels; (ii) the Company’s formation of a joint venture (the “Venture”) with MAP Ground Lease Owner LLC, an affiliate of Och-Ziff (the “O-Z Venture Partner”), and the Company’s sale to the Venture of the office buildings and related improvements (the “Buildings”) situated on the Land Parcels; and (iii) the retention of a non-controlling equity interest in the Venture. The transaction agreements provide for the Venture to engage a subsidiary of the Company to provide customary property management services in an amount equal to 2.5% of gross rental receipts. The initial term is through December 31, 2016 and is renewed automatically each year unless terminated. The Company may be terminated without cause, subject to a ninety day notification. The Company intends to use the net cash proceeds that it received in the transaction for general corporate purposes, including to reduce its outstanding debt and fund current development commitments. Based upon the facts and circumstances at formation of the Venture, the Company determined that the 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 Venture. Based upon each member’s power to control the activities that most significantly impact the economics of the Venture under the operating and related agreements of the Venture, it is accounted for under the equity method of accounting. Reportable Segments During the year ended December 31, 2015, the Company was managing 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 four core markets 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 will be managed as a consolidated segment entitled “Other,” as these geographies no longer provide a significant revenue contribution. Accordingly, the chief operating decision maker is revising the management structure and allocating more resources to the four core markets beginning January 1, 2016. The Company has evaluated subsequent events through the date the financial statements were issued.

Summary of Quarterly Results

Summary of Quarterly Results	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014 (in thousands, except per share data): 1st 2nd 3rd 4th Quarter Quarter Quarter Quarter 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 ) 2014 Total revenue $ 152,114 $ 150,500 $ 146,558 $ 147,810 Net income (loss) (2,245 ) 2,174 8,882 (1,869 ) Net income (loss) allocated to Common Shares (4,041 ) 385 6,967 (3,585 ) Basic earnings (loss) per Common Share $ (0.03 ) $ - $ 0.04 $ (0.02 ) Diluted earnings (loss) per Common Share $ (0.03 ) $ - $ 0.04 $ (0.02 ) 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, 2015
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, 2015 $ 15,347 $ 2,640 $ 1,809 $ 16,178 Year-ended December 31, 2014 $ 16,248 $ 790 $ 1,691 $ 15,347 Year-ended December 31, 2013 $ 16,646 $ 1,384 $ 1,782 $ 16,248 (1) Deductions represent amounts that the Company had fully reserved for in prior years and 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, 2015
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, 2015 (in thousands) Initial Cost Gross Amount Which Carried December 31, 2015 (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, 2015 (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 6,357 1999 1999 40 300 Berwyn Park Berwyn PA - 2,206 13,422 3,896 2,206 17,318 19,524 8,603 1989 1997 40 1050 Westlakes Drive Berwyn PA - 2,611 10,445 5,056 2,611 15,501 18,112 8,686 1984 1999 40 1200 Swedesford Road Berwyn PA - 2,595 11,809 3,533 2,595 15,342 17,937 7,454 1994 2001 40 200 Berwyn Park Berwyn PA - 1,533 9,460 2,178 1,533 11,638 13,171 5,846 1987 1997 40 1180 Swedesford Road Berwyn PA - 2,086 8,342 2,978 2,086 11,320 13,406 3,952 1987 2001 40 100 Berwyn Park Berwyn PA - 1,180 7,290 1,948 1,180 9,238 10,418 4,696 1986 1997 40 1160 Swedesford Road Berwyn PA - 1,781 7,124 6,108 2,045 12,968 15,013 3,689 1986 2001 40 1100 Cassett Road Berwyn PA - 1,695 6,779 1,272 1,695 8,051 9,746 2,847 1997 2001 40 980 Harvest Drive (d), (e) Blue Bell PA - 2,079 8,315 149 1,949 8,594 10,543 3,069 1988 2002 40 910 Harvest Drive (d) Blue Bell PA - 1,225 8,645 (718) 1,225 7,927 9,152 4,822 1990 1998 40 925 Harvest Drive (d) Blue Bell PA - 1,671 6,606 913 1,671 7,519 9,190 3,539 1990 1998 40 920 Harvest Drive (d) Blue Bell PA - 1,208 6,595 (427) 1,208 6,168 7,376 2,892 1990 1998 40 181 Washington Street Conshohocken PA - 6,927 14,722 318 6,237 15,730 21,967 1,215 1999 2013 40 426 Lancaster Avenue Devon PA - 1,689 6,756 376 1,689 7,132 8,821 3,621 1990 1998 40 52 Swedesford Square East Whiteland Twp. PA - 4,241 16,579 1,852 4,241 18,431 22,672 8,115 1988 1998 40 One Progress Drive (d), (e) Horsham PA - 1,399 5,629 3,802 1,127 9,703 10,830 4,883 1986 1996 40 500 Enterprise Drive (d) Horsham PA - 1,303 5,188 3,709 1,303 8,897 10,200 4,624 1990 1996 40 640 Freedom Business Center King Of Prussia PA - 4,222 16,891 4,760 4,222 21,651 25,873 10,262 1991 1998 40 555 Croton Road (d), (e) King of Prussia PA - 4,486 17,943 (228) 4,024 18,177 22,201 7,337 1999 2001 40 630 Allendale Road King of Prussia PA - 2,836 4,028 12,595 2,898 16,561 19,459 6,083 2000 2000 40 620 Freedom Business Center King Of Prussia PA - 2,770 11,014 3,700 2,770 14,714 17,484 8,116 1986 1998 40 1000 First Avenue King Of Prussia PA - 2,772 10,936 1,912 2,772 12,848 15,620 5,898 1980 1998 40 1060 First Avenue King Of Prussia PA - 2,712 10,953 3,585 2,712 14,538 17,250 6,418 1987 1998 40 630 Freedom Business Center King Of Prussia PA - 2,773 11,144 1,991 2,773 13,135 15,908 6,403 1989 1998 40 1020 First Avenue King Of Prussia PA - 2,168 8,576 7,627 2,168 16,203 18,371 7,618 1984 1998 40 1040 First Avenue King Of Prussia PA - 2,860 11,282 5,037 2,860 16,319 19,179 6,079 1985 1998 40 610 Freedom Business Center King Of Prussia PA - 2,017 8,070 2,477 2,017 10,547 12,564 5,363 1985 1998 40 650 Park Avenue King Of Prussia PA - 1,916 4,378 1,655 1,916 6,033 7,949 3,129 1968 1998 40 500 North Gulph Road King Of Prussia PA - 1,303 5,201 1,445 1,303 6,646 7,949 3,577 1979 1996 40 620 Allendale Road King Of Prussia PA - 1,020 3,839 628 1,020 4,467 5,487 2,132 1961 1998 40 600 Park Avenue King Of Prussia PA - 1,012 4,048 385 1,012 4,433 5,445 2,166 1964 1998 40 660 Allendale Road King Of Prussia PA - 396 948 2,957 1,085 3,216 4,301 1,219 2011 1998 40 640 Allendale Road King of Prussia PA - 439 432 1,507 439 1,939 2,378 808 2000 2000 40 14 Campus Boulevard Newtown Square PA - 2,244 4,217 1,533 2,244 5,750 7,994 3,665 1998 1998 40 17 Campus Boulevard Newtown Square PA - 1,108 5,155 (374) 1,108 4,781 5,889 1,939 2001 1997 40 11 Campus Boulevard Newtown Square PA - 1,112 4,067 997 1,112 5,064 6,176 2,116 1998 1999 40 15 Campus Boulevard Newtown Square PA - 1,164 3,896 247 1,164 4,143 5,307 1,519 2002 2000 40 18 Campus Boulevard Newtown Square PA - 787 3,312 478 787 3,790 4,577 1,649 1990 1996 40 401 Plymouth Road Plymouth Meeting PA - 6,199 16,131 16,709 6,199 32,840 39,039 11,265 2001 2000 40 4000 Chemical Road Plymouth Meeting PA - 4,373 24,546 1,484 4,373 26,030 30,403 5,570 2006 2001 40 610 West Germantown Pike Plymouth Meeting PA - 3,651 14,514 3,375 3,651 17,889 21,540 6,508 1987 2002 40 600 West Germantown Pike Plymouth Meeting PA - 3,652 15,288 1,985 3,652 17,273 20,925 5,902 1986 2002 40 630 West Germantown Pike Plymouth Meeting PA - 3,558 14,743 997 3,558 15,740 19,298 5,537 1988 2002 40 620 West Germantown Pike Plymouth Meeting PA - 3,572 14,435 963 3,572 15,398 18,970 5,551 1990 2002 40 660 West Germantown Pike Plymouth Meeting PA - 3,694 5,487 19,418 5,405 23,194 28,599 2,357 1987 2012 30 2240/2250 Butler Pike (d) Plymouth Meeting PA - 1,104 4,627 1,312 1,104 5,939 7,043 3,888 1984 1996 40 2260 Butler Pike (d), (e) Plymouth Meeting PA - 662 2,727 2,009 550 4,848 5,398 2,460 1984 1996 40 120 West Germantown Pike (d) Plymouth Meeting PA - 685 2,773 667 685 3,440 4,125 1,861 1984 1996 40 140 West Germantown Pike (d) Plymouth Meeting PA - 482 1,976 282 482 2,258 2,740 1,181 1984 1996 40 351 Plymouth Road Plymouth Meeting PA - 1,043 555 - 1,043 555 1,598 149 N/A 2000 40 150 Radnor Chester Road Radnor PA - 11,925 36,986 12,574 11,897 49,588 61,485 18,681 1983 2004 29 One Radnor Corporate Center Radnor PA - 7,323 28,613 23,135 7,323 51,748 59,071 21,189 1998 2004 29 201 King of Prussia Road Radnor PA - 8,956 29,811 4,530 8,949 34,348 43,297 16,172 2001 2004 25 555 Lancaster Avenue Radnor PA - 8,014 16,508 16,414 8,609 32,327 40,936 13,850 1973 2004 24 Four Radnor Corporate Center Radnor PA - 5,406 21,390 14,393 5,705 35,484 41,189 11,578 1995 2004 30 Five Radnor Corporate Center Radnor PA - 6,506 25,525 5,512 6,578 30,965 37,543 9,253 1998 2004 38 Three Radnor Corporate Center Radnor PA - 4,773 17,961 2,540 4,791 20,483 25,274 9,029 1998 2004 29 Two Radnor Corporate Center Radnor PA - 3,937 15,484 3,883 3,942 19,362 23,304 7,797 1998 2004 29 130 Radnor Chester Road Radnor PA - 2,573 8,338 3,483 2,567 11,827 14,394 4,895 1983 2004 25 170 Radnor Chester Road Radnor PA - 2,514 8,147 2,486 2,509 10,638 13,147 3,488 1983 2004 25 200 Radnor Chester Road Radnor PA - 3,366 - 3,583 3,366 3,583 6,949 239 2014 2005 40 101 West Elm Street W. Conshohocken PA - 6,251 25,209 3,483 6,251 28,692 34,943 8,481 1999 2005 40 1 West Elm Street W. Conshohocken PA - 3,557 14,249 3,069 3,557 17,318 20,875 4,089 1999 2005 40 PHILADELPHIA CBD 2970 Market Street (d) (f) Philadelphia PA 177,425 22,430 217,763 25,597 22,430 243,360 265,790 34,339 2010 2007 40 2929 Arch Street Philadelphia PA - - 208,570 27,724 12,586 223,708 236,294 93,087 2005 N/A 40 1717 Arch Street Philadelphia PA - - 98,188 68,523 25,195 141,516 166,711 26,182 1990 2010 40 2001 Market Street Philadelphia PA 112,000 15,323 120,200 17,323 15,323 137,523 152,846 7,332 1992 2013 40 130 North 18th Street Philadelphia PA - 14,496 107,736 27,407 14,473 135,166 149,639 41,218 1998 2004 34 100 North 18th Street Philadelphia PA 86,886 16,066 100,255 12,834 16,066 113,089 129,155 33,526 1988 2004 36 2005 Market Street Philadelphia PA 130,000 15,161 105,021 14,907 15,161 119,928 135,089 6,783 1987 2013 40 Cira Centre South Garage (f) Philadelphia PA 35,546 - 76,008 2,538 - 78,546 78,546 10,467 2010 N/A 40 1900 Market Street Philadelphia PA - 7,768 17,263 17,545 7,768 34,808 42,576 2,093 1981 2012 30 3020 Market Street Philadelphia PA - - 21,417 7,975 - 29,392 29,392 4,685 1959 2011 26 101 - 103 Juniper Street Philadelphia PA - - 14,401 324 478 14,247 14,725 2,390 2010 2006 40 Philadelphia Marine Center Philadelphia PA - 532 2,196 3,444 628 5,544 6,172 2,679 Various 1998 40 618-634 Market Street (g) Philadelphia PA - 13,365 5,791 - 13,365 5,791 19,156 869 1966 2015 5 METROPOLITAN WASHINGTON, D.C. 11720 Beltsville Drive (h) Beltsville MD - 3,831 16,661 (5,279) 1,927 13,286 15,213 6,581 1987 2006 46 11700 Beltsville Drive (h) Beltsville MD - 2,808 12,081 (10,493) 336 4,060 4,396 2,963 1981 2006 46 11710 Beltsville Drive (h) Beltsville MD - 2,278 11,100 (8,534) 534 4,310 4,844 2,560 1987 2006 46 6600 Rockledge Drive Bethesda MD - - 37,421 10,749 - 48,170 48,170 10,174 1981 2006 50 11740 Beltsville Drive (h) Bethesda MD - 198 870 42 202 908 1,110 233 1987 2006 46 12015 Lee Jackson Memorial Highway (d), (e) Fairfax VA - 3,770 22,895 1,902 3,561 25,006 28,567 7,574 1985 2006 42 11781 Lee Jackson Memorial Highway (d), (e) Fairfax VA - 3,246 19,836 (1,435) 2,615 19,032 21,647 5,512 1982 2006 40 4401 Fair Lakes Court (d), (e) Fairfax VA - 1,569 11,982 (2,098) 990 10,463 11,453 2,766 1988 2006 52 3141 Fairview Park Drive (i) Falls Church VA 20,838 5,918 40,981 14,119 7,081 53,937 61,018 11,640 1988 2006 51 2340 Dulles Corner Boulevard Herndon VA - 16,345 65,379 18,280 16,129 83,875 100,004 31,570 1987 2006 40 2291 Wood Oak Drive Herndon VA - 8,243 52,413 12,524 8,782 64,398 73,180 15,294 1999 2006 55 196/198 Van Buren Street Herndon VA - 7,931 43,812 9,059 8,348 52,454 60,802 11,986 1991 2006 53 2251 Corporate Park Drive Herndon VA - 11,472 45,893 3,367 11,472 49,260 60,732 11,204 2000 2006 40 2355 Dulles Corner Boulevard Herndon VA - 10,365 43,876 4,612 10,365 48,488 58,853 13,849 1988 2006 40 2411 Dulles Corner Park Herndon VA - 7,279 46,340 16,028 7,417 62,230 69,647 10,822 1990 2006 50 13880 Dulles Corner Lane Herndon VA - 7,236 39,213 4,556 7,373 43,632 51,005 9,193 1997 2006 55 2121 Cooperative Way Herndon VA - 5,598 38,639 2,688 5,795 41,130 46,925 8,879 2000 2006 54 2201 Cooperative Way Herndon VA - 4,809 34,093 5,317 4,809 39,410 44,219 8,573 1990 2006 54 13825 Sunrise Valley Drive Herndon VA - 3,794 19,365 2,126 3,866 21,419 25,285 5,398 1989 2006 46 1676 International Drive (j) Mclean VA - 18,437 97,538 3,740 18,785 100,930 119,715 19,257 1999 2006 55 8260 Greensboro Drive (j) Mclean VA - 7,952 33,964 2,227 8,102 36,041 44,143 7,898 1980 2006 52 2273 Research Boulevard Rockville MD - 5,167 31,110 4,638 5,237 35,678 40,915 10,292 1999 2006 45 2275 Research Boulevard Rockville MD - 5,059 29,668 7,413 5,154 36,986 42,140 9,057 1990 2006 45 2277 Research Boulevard Rockville MD - 4,649 26,952 17,817 4,733 44,685 49,418 7,715 1986 2006 45 1900 Gallows Road Vienna VA - 7,797 47,817 11,469 7,944 59,139 67,083 13,191 1989 2006 52 8521 Leesburg Pike Vienna VA - 4,316 30,885 5,280 4,397 36,084 40,481 7,393 1984 2006 51 NEW JERSEY/DELAWARE 200 Lake Drive East Cherry Hill NJ - 2,069 8,275 1,798 2,069 10,073 12,142 3,922 1989 2001 40 220 Lake Drive East Cherry Hill NJ - 2,144 8,798 1,955 2,144 10,753 12,897 3,818 1988 2001 40 210 Lake Drive East Cherry Hill NJ - 1,645 6,579 2,748 1,645 9,327 10,972 3,102 1986 2001 40 20 East Clementon Road Gibbsboro NJ - 769 3,055 401 769 3,456 4,225 1,712 1986 1997 40 10 Foster Avenue Gibbsboro NJ - 244 971 78 244 1,049 1,293 525 1983 1997 40 7 Foster Avenue Gibbsboro NJ - 231 921 123 231 1,044 1,275 514 1983 1997 40 50 East Clementon Road Gibbsboro NJ - 114 964 671 114 1,635 1,749 584 1986 1997 40 2 Foster Avenue Gibbsboro NJ - 185 730 16 185 746 931 369 1974 1997 40 4 Foster Avenue Gibbsboro NJ - 183 726 16 183 742 925 362 1974 1997 40 1 Foster Avenue Gibbsboro NJ - 93 364 57 93 421 514 228 1972 1997 40 5 U.S. Avenue Gibbsboro NJ - 21 81 3 21 84 105 41 1987 1997 40 5 Foster Avenue Gibbsboro NJ - 9 32 26 9 58 67 30 1968 1997 40 Two Eves Drive Marlton NJ - 818 3,461 269 818 3,730 4,548 1,761 1987 1997 40 Five Eves Drive Marlton NJ - 703 2,819 1,437 703 4,256 4,959 1,760 1986 1997 40 Four B Eves Drive Marlton NJ - 588 2,369 185 588 2,554 3,142 1,311 1987 1997 40 Four A Eves Drive Marlton NJ - 539 2,168 376 539 2,544 3,083 1,215 1987 1997 40 308 Harper Drive (d), (e) Moorestown NJ - 1,643 6,663 (39) 1,425 6,842 8,267 3,481 1976 1998 40 1120 Executive Boulevard Mt. Laurel NJ - 2,074 8,415 4,280 2,074 12,695 14,769 5,696 1987 1997 40 700 East Gate Drive (d) Mt. Laurel NJ - 3,569 14,436 1,956 3,569 16,392 19,961 7,573 1984 1998 40 701 East Gate Drive (d), (e) Mt. Laurel NJ - 1,736 6,877 1,163 1,589 8,187 9,776 4,033 1986 1998 40 307 Fellowship Drive (d), (e) Mt. Laurel NJ - 1,565 6,342 306 1,330 6,883 8,213 3,551 1981 1998 40 305 Fellowship Drive (d), (e) Mt. Laurel NJ - 1,421 5,768 920 1,233 6,876 8,109 3,340 1980 1998 40 303 Fellowship Drive (d), (e) Mt. Laurel NJ - 1,493 6,055 205 1,250 6,503 7,753 3,213 1979 1998 40 309 Fellowship Drive (d) Mt. Laurel NJ - 1,518 6,154 711 1,518 6,865 8,383 3,206 1982 1998 40 161 Gaither Drive (d), (e) Mt. Laurel NJ - 1,016 4,064 535 1,011 4,604 5,615 1,724 1987 2001 40 815 East Gate Drive (d), (e) Mt. Laurel NJ - 636 2,584 446 581 3,085 3,666 1,532 1986 1998 40 817 East Gate Drive (d), (e) Mt. Laurel NJ - 611 2,426 216 600 2,653 3,253 1,247 1986 1998 40 Main Street - Plaza 1000 Voorhees NJ - 2,732 10,942 96 2,732 11,038 13,770 11,002 1988 1997 40 Main Street - Piazza Voorhees NJ - 696 2,802 3,360 696 6,162 6,858 2,035 1990 1997 40 Main Street - Promenade Voorhees NJ - 532 2,052 538 532 2,590 3,122 1,288 1988 1997 40 920 North King Street Wilmington DE - 6,141 21,140 2,707 6,141 23,847 29,988 8,113 1989 2004 30 300 Delaware Avenue Wilmington DE - 6,369 13,739 2,889 6,369 16,628 22,997 7,496 1989 2004 23 AUSTIN, TX 11501 Burnet Road - Building 1 Austin TX - 3,755 22,702 119 3,755 22,821 26,576 358 1991 2015 35 11501 Burnet Road - Building 2 Austin TX - 2,732 16,305 654 2,732 16,959 19,691 274 1991 2015 35 11501 Burnet Road - Building 3 Austin TX - 3,688 22,348 118 3,688 22,466 26,154 353 1991 2015 35 11501 Burnet Road - Building 4 Austin TX - 2,614 15,740 83 2,614 15,823 18,437 248 1991 2015 35 11501 Burnet Road - Building 5 Austin TX - 3,689 22,354 117 3,689 22,471 26,160 353 1991 2015 35 11501 Burnet Road - Building 6 Austin TX - 2,676 15,972 84 2,676 16,056 18,732 252 1991 2015 35 11501 Burnet Road - Building 8 Austin TX - 1,400 7,422 39 1,400 7,461 8,861 122 1991 2015 35 11501 Burnet Road - Parking Garage Austin TX - - 19,826 103 - 19,929 19,929 424 1991 2015 35 RICHMOND 4364 South Alston Avenue (d), (e) Durham NC - 1,622 6,419 (454) 1,144 6,443 7,587 3,512 1985 1998 40 4805 Lake Brooke Drive (d), (e) Glen Allen VA - 1,640 6,567 703 1,420 7,490 8,910 3,576 1996 1998 40 Overlook I (d) Glen Allen VA - 748 3,976 600 791 4,533 5,324 916 1998 2011 40 Overlook II (d) Glen Allen VA - 748 4,492 504 791 4,953 5,744 923 2000 2011 40 2812 Emerywood Parkway (d) Henrico VA - 1,069 4,281 670 1,069 4,951 6,020 2,290 1980 1998 40 300 Arboretum Place (d), (e) Richmond VA - 5,450 21,892 3,831 4,674 26,499 31,173 12,104 1988 1998 40 7501 Boulders View Drive (d), (e) Richmond VA - 4,669 19,699 (2,770) 3,920 17,678 21,598 4,891 1989 2007 40 7300 Beaufont Springs Drive (d), (e) Richmond VA - 4,672 19,689 (1,080) 3,980 19,301 23,281 4,999 2000 2007 40 6800 Paragon Place (d), (e) Richmond VA - 4,552 18,414 (681) 3,821 18,464 22,285 5,456 1987 2006 40 6802 Paragon Place (d) Richmond VA - 2,917 11,454 3,074 2,917 14,528 17,445 5,706 1989 2002 40 1025 Boulders Parkway (d), (e) Richmond VA - 2,574 11,297 (1,314) 2,040 10,517 12,557 3,009 1994 2007 40 2100-2116 West Laburnam Avenue (d) Richmond VA - 2,482 8,846 2,742 2,482 11,588 14,070 5,331 1984 1998 40 7401 Beaufont Springs Drive (d), (e) Richmond VA - 2,349 10,396 (2,048) 1,788 8,909 10,697 2,649 1998 2007 40 7325 Beaufont Springs Drive (d), (e) Richmond VA - 2,344 10,377 (1,745) 2,002 8,974 10,976 2,349 1999 2007 40 9011 Arboretum Parkway (d), (e) Richmond VA - 1,857 7,702 (430) 1,501 7,628 9,129 4,104 1991 1998 40 6806 Paragon Place (d) Richmond VA - - 10,288 (117) 403 9,768 10,171 2,885 2007 2005 40 9100 Arboretum Parkway (d), (e) Richmond VA - 1,362 5,489 541 1,274 6,118 7,392 2,974 1987 1998 40 2511 Brittons Hill Road (d) Richmond VA - 1,202 4,820 1,221 1,202 6,041 7,243 3,041 1987 1998 40 9200 Arboretum Parkway (d) Richmond VA - 985 3,973 1,275 985 5,248 6,233 2,562 1987 1998 40 9210 Arboretum Parkway (d), (e) Richmond VA - 1,110 4,474 167 970 4,781 5,751 2,274 1988 1998 40 2201-2245 Tomlynn Street (d) Richmond VA - 1,020 4,067 1,126 1,020 5,193 6,213 2,332 1989 1998 40 9211 Arboretum Parkway (d), (e) Richmond VA - 582 2,433 317 470 2,862 3,332 1,395 1991 1998 40 2221-2245 Dabney Road (d) Richmond VA - 530 2,123 369 530 2,492 3,022 1,091 1994 1998 40 2212-2224 Tomlynn Street (d) Richmond VA - 502 2,014 487 502 2,501 3,003 1,109 1985 1998 40 2244 Dabney Road (d) Richmond VA - 550 2,203 - 550 2,203 2,753 1,016 1993 1998 40 2277 Dabney Road (d) Richmond VA - 507 2,034 294 507 2,328 2,835 1,077 1986 1998 40 2248 Dabney Road (d), (e) Richmond VA - 512 2,049 379 503 2,437 2,940 1,000 1989 1998 40 2161-2179 Tomlynn Street (d) Richmond VA - 423 1,695 306 423 2,001 2,424 867 1985 1998 40 2246 Dabney Road (d) Richmond VA - 455 1,822 - 455 1,822 2,277 841 1987 1998 40 2251 Dabney Road (d) Richmond VA - 387 1,552 59 387 1,611 1,998 740 1983 1998 40 2256 Dabney Road (d) Richmond VA - 356 1,427 225 356 1,652 2,008 777 1982 1998 40 2130-2146 Tomlynn Street (d) Richmond VA - 353 1,416 225 353 1,641 1,994 779 1988 1998 40 2112-2124 Tomlynn Street (d) Richmond VA - 281 1,125 306 281 1,431 1,712 695 1984 1998 40 2240 Dabney Road (d) Richmond VA - 264 1,059 88 264 1,147 1,411 514 1984 1998 40 Boulders Land (d), (e) Richmond VA - 1,256 - (116) 1,115 25 1,140 3 N/A 2007 N/A CALIFORNIA 1200 Concord Avenue Concord CA - 6,395 24,664 833 6,515 25,377 31,892 9,192 1984 2006 34 1220 Concord Avenue Concord CA - 6,476 24,966 298 6,476 25,264 31,740 8,869 1984 2006 34 Oakland Lot B Oakland CA - 4,342 - 17 4,332 27 4,359 - N/A 2006 N/A Total: $ 562,695 $ 589,391 $ 3,246,749 $ 651,448 $ 619,181 $ 3,868,407 $ 4,487,588 $ 1,080,616 (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, 2013 to December 31, 2015 (in thousands): 2015 2014 2013 Balance at beginning of year $ 4,631,128 $ 4,669,289 $ 4,726,169 Additions: Acquisitions 182,381 - 347,510 Capital expenditures and assets placed into service 165,941 132,149 109,740 Less: Dispositions (442,327 ) (126,471 ) (474,275 ) Retirements (49,535 ) (43,839 ) (39,855 ) Balance at end of year $ 4,487,588 $ 4,631,128 $ 4,669,289 Less: Assets held for sale (794,588 ) (27,436 ) - Per consolidated balance sheet $ 3,693,000 $ 4,603,692 $ 4,669,289 The aggregate cost for federal income tax purposes is $3.9 billion as of December 31, 2015. (c) Reconciliation of Accumulated Depreciation: The following table reconciles the accumulated depreciation on real estate investments from January 1, 2013 to December 31, 2015 (in thousands): 2015 2014 2013 Balance at beginning of year $ 1,078,996 $ 983,808 $ 954,665 Additions: Depreciation expense — continuing operations 159,080 160,641 150,236 Depreciation expense — discontinued operations - - 9,164 Less: Dispositions (109,243 ) (22,459 ) (91,890 ) Retirements (48,217 ) (42,994 ) (38,367 ) Balance at end of year $ 1,080,616 $ 1,078,996 $ 983,808 Less: Assets held for sale (213,581 ) (11,167 ) - Per consolidated balance sheet $ 867,035 $ 1,067,829 $ 983,808 (d) Properties were held for sale at December 31, 2015. For further information see Note 3, “ Real Estate Investments (e) Properties were held for sale at December 31, 2015. In connection with the held for sale determination the Company recorded an impairment charge of $45.4 million as of December 31, 2015, reducing the aggregate carrying value of these properties from $426.2 million to the sales price less estimated closing costs of $380.8 million in connection with the anticipated disposition. The impairment was allocated between land and building. For further information see Note 3, “ Real Estate Investments (f) Mortgage debt on these properties was repaid subsequent to December 31, 2015. For further information see Note 21, “ Subsequent Events (g) At acquisition it was determined that the useful life of the parking structure is five years, which reflects the expected demolition date. (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 $27.5 million as of December 31, 2015, reducing the aggregate carrying value of these properties from $40.4 million to their estimated fair value of $12.9 million. For further information see Note 3, “ Real Estate Investments ( i ) This property was contributed to an unconsolidated real estate venture, however, the Company will continue to consolidate this property due to its continuing involvement in this property resulting from its ongoing lease at this property and its 50% ownership interest in the venture. Please see Note 3, “ Real Estate Investments, (j) On October 9, 2015, the Company funded the full repayment of the Tysons Corner mortgage note.

Summary of Significant Accoun35

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Reclassifications	Reclassifications Reclassifications are related to the treatment of sold properties as discontinued operations on the statement of operations for all periods presented. During the fourth quarter of 2015, the Company adopted ASU 2015-03, Simplifying the Presentation of Debt Issuances Costs (“ASU 2015-03”) eferred financing costs associated with our credit facility remain in deferred costs (assets) on the consolidated balance sheet Recent Accounting Pronouncements
Principles of Consolidation	Principles of Consolidation When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity (“VIE”), and if the Company is deemed to be the primary beneficiary, in accordance with the accounting standard for the consolidation of variable interest entities. The accounting standard for the consolidation of VIEs requires the Company to qualitatively assess if the Company was the primary beneficiary of the VIEs based on whether the Company had (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 determined to be VIEs, but for which the Company is not the primary beneficiary, the Company’s maximum exposure to loss is the carrying amount of its investments. As of December 31, 2015, the Company has provided guarantees on behalf of certain real estate ventures, consisting of: (i) a $24.7 million payment guaranty on the construction loan for evo at Cira; (ii) a $3.2 million payment guarantee on the construction loan for TB-BDN Plymouth Apartments; (iii) a several cost overrun guaranty on the $88.9 million construction loan for the development project being undertaken by 1919 Ventures; and (iv) a $0.5 million payment guarantee on a loan provided to PJP VII. When an entity is not deemed to be a VIE, the Company considers the provisions of the same accounting standard to determine whether a general partner/managing member, or the general partners/managing members as a group, controls a limited partnership or similar entity when the limited partners/non-managing members have certain rights. The Company consolidates (i) entities that are VIEs and of which the Company is deemed to be the primary beneficiary and (ii) entities that are non-VIEs and are controlled by the Company and in which the limited partners neither have the ability to dissolve the entity or remove the Company without cause nor any substantive participating rights. The Company continuously assesses its determination of whether an entity is a VIE and who the primary beneficiary is, and whether or not the limited partners/non-managing members in an entity have substantive rights, more particularly if certain events occur that are likely to cause a change in the original determinations. The Company’s assessment includes a review of applicable documents such as, but not limited to, applicable partnership agreements, limited liability company and other real estate venture agreements and management and leasing agreements to determine whether the Company has control to direct the business activities of the entities. 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, 2015, the Company included in its consolidated balance sheets consolidated VIEs having total assets of $422.9 million and total liabilities of $258.2 million.
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, 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. Major replacements and betterments, which improve or extend the life of the asset, are capitalized and depreciated over their estimated useful lives.
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 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 rentals 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. Though the Company considers the value of tenant relationships, the amounts are determined on a tenant-specific basis. On certain of our acquisitions this intangible has been deemed immaterial. In these instances no related intangible 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 $7.3 million in 2015, $5.2 million in 2014, $3.7 million in 2013 and interest totaling $10.2 million in 2015, $4.8 million in 2014, and $2.6 million in 2013 were capitalized related to development of certain properties and land holdings. The increase in capitalized costs is due to the development activity. See Item 1., “ Business - Developments, During the years ended December 31, 2015, 2014 and 2013, 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, 2015 2014 2013 Development $ 2,641 $ 1,749 $ 156 Redevelopment 221 184 194 Tenant Improvements 4,429 3,261 3,323 Total $ 7,291 $ 5,194 $ 3,673
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 our impairment analysis. The Company update 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. 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 our 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 consider assets to be “held for sale” when the transaction has been approved by our 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 equal to the difference and reduces the net carrying value of the property. 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).
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 financial institutions in excess of insured limits, but believes this risk is mitigated by only investing in or through major financial institutions.
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.
Accounts Receivable And Accrued Rent Receivable	Accounts Receivable and Accrued Rent Receivable 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 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, 2015 and 2014, 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 $1.7 million and $14.5 million in 2015, respectively and $2.0 million and $13.4 million in 2014, 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 The Company accounts for its investments in unconsolidated Real Estate Ventures under the equity method of accounting as it is not the primary beneficiary (for VIEs) and the Company exercises significant influence, but does not control these entities under the provisions of the entities’ governing agreements pursuant to the accounting standard for the consolidation of VIEs. When the Company determines that its investment in an unconsolidated Real Estate Venture does not constitute a VIE, the Company utilizes the voting interest model under the accounting standard for consolidation to determine whether to consolidate the venture. Under the equity method, investments in unconsolidated Real Estate Ventures are recorded initially at cost, as investments in Real Estate Ventures, and subsequently adjusted for equity in earnings, cash contributions, less 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. In each of the twelve months ended December 31, 2015 and 2014 the Company capitalized interest expense of $2.0 million. During the twelve months ended December 31, 2013, the Company capitalized interest expense of $0.6 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 15 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. On October 17, 2014, the Austin Venture acquired River Place (See Note 4, “ Investment in Unconsolidated Real Estate Ventures
Deferred Financing Costs	Deferred Financing Costs Costs incurred in connection with debt financing are capitalized as deferred financing costs and 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 During the fourth quarter of 2015, the Company adopted accounting guidance related to the presentation of deferred financing costs on the balance sheet and reclassified amounts from the deferred costs line (assets) to net against the debt liability for all periods presented. See Recent Accounting Pronouncements
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 $21.6 million in 2015, $13.7 million in 2014 and $17.7 million in 2013. 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 $2.0 million in 2015 and $2.4 million in each of 2014 and 2013. 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 $1.8 million in 2015, $1.5 million in 2014, and $0.7 million in 2013. 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. 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. 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. 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, management fees and development fees from third parties. 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 write 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. No tenant represented greater than 10% of the Company’s rental revenue in 2015, 2014 or 2013.
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, no 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 $3.9 billion and $3.7 billion for the years ended December 31, 2015 and 2014, 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 2015, 2014 or 2013. 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, 2015 and 2014. 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. We expect that the changes will not materially impact our 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 $3.9 billion and $3.7 billion for the years ended December 31, 2015 and 2014, 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 shares of common stock 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, 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.
Stock-Based Compensation Plans	Stock-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, 2015, 4,295,559 common shares remained available for future awards under the 1997 Plan (including 2,624,067 shares available solely for options and share appreciation rights). Through December 31, 2015, all options awarded under the 1997 Plan had a one to ten-year term. The Company incurred stock-based compensation expense of $7.3 million during 2015, of which $1.9 million was capitalized as part of the Company’s review of employee salaries eligible for capitalization. The Company incurred stock-based compensation on expense of $6.1 million and $8.3 million during 2014 and 2013, of which $1.7 million and $1.4 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 September 2015, the Financial Accounting Standards Board ("FASB") issued guidance pertaining to entities that have reported provisional amounts for items in a business combination for which the accounting is incomplete by the end of the reporting period in which the combination occurs and during the measurement period have an adjustment to provisional amounts recognized. The guidance requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. Any adjustments should be calculated as if the accounting had been completed at the acquisition date. The guidance is effective for public companies for fiscal years beginning after December 15, 2016, with early adoption permitted. Application of the guidance is prospective. On July 9, 2015, the FASB elected to defer the effective date of the revenue recognition standard issued in May 2014 by one year. Reporting entities may choose to adopt the standard as of the original effective date or for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2017. Calendar year-end public entities are therefore required to apply the new revenue guidance beginning in their 2018 interim and annual financial statements. The Company has not yet determined the impact, if any, that the adoption of this guidance will have on its consolidated financial statements. In April 2015, the FASB issued guidance requiring that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by this update. Additionally, in August 2015 the FASB issued guidance expanding the April 2015 update. It states that, given the absence of authoritative guidance within the update, the SEC staff would not object to an entity deferring and presenting debt issuance costs as an asset for revolving lines of credit and subsequently amortizing the deferred debt issuance costs ratably over the term of the arrangement, regardless of whether there are any outstanding borrowings on the line of credit. This guidance is effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years, with early adoption permitted for financial statements that have not been previously issued. Full retrospective application is required. Early adoption is permitted. The Company elected to early adopt this guidance during the fourth quarter of 2015 and reclassify amounts in each period presented. The adoption of this guidance did not have a material impact on our consolidated financial position or results of operations as the update relates only to changes in financial statement presentation. See “ Reclassifications In February 2015, the FASB issued guidance modifying the analysis a reporting entity must perform to determine whether it should consolidate certain types of legal entities. The guidance does not change the general order in which the consolidation models are applied. A reporting entity that holds an economic interest in, or is otherwise involved with, another legal entity must first determine if the variable interest entity model applies, and if so, whether it holds a controlling financial interest under that model. If the entity being evaluated for consolidation is not a variable interest entity, then the voting interest model should be applied to determine whether the entity should be consolidated by the reporting entity. Key changes to the guidance include, but are not limited to: (i) limiting the extent to which related party interests are included to determine the decision maker’s effective financial interest in the entity, (ii) requiring that the limited partners in the limited partnership (or the members of a limited liability company that is similar to a limited partnership) have either substantive kick-out rights or substantive participating rights over the general partner to demonstrate that the limited partnership is a voting interest entity, (iii) changing the evaluation of whether the equity holders at risk lack decision making rights when decision making is outsourced and (iv) changing how the economics test is performed. The guidance does not amend the existing disclosure requirements for variable interest entities or voting interest model entities. The guidance is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2015. Early adoption is permitted. A reporting entity may elect to either apply the amendments using a modified retrospective approach by recording a cumulative-effect adjustment to equity as of the beginning of the fiscal year of adoption or apply the amendments retrospectively. Under the revised guidance, the Operating Partnership will be a variable interest entity of the Parent Company. As the Operating Partnership is already consolidated in the balance sheets of the Parent Company, the identification of this entity as a variable interest entity has no impact on the consolidated financial statements of the Parent Company. The Company has determined that the adoption of this guidance will not have a significant impact on our existing consolidation conclusions and we plan to adopt the guidance as of January 1, 2016.

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Compensation Costs (Including Bonuses and Benefits) Capitalized	During the years ended December 31, 2015, 2014 and 2013, 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, 2015 2014 2013 Development $ 2,641 $ 1,749 $ 156 Redevelopment 221 184 194 Tenant Improvements 4,429 3,261 3,323 Total $ 7,291 $ 5,194 $ 3,673

Real Estate Investments (Tables

Real Estate Investments (Tables)	12 Months Ended
	Dec. 31, 2015
Real Estate Properties [Line Items]
Gross Carrying Value Of Company's Properties	As of December 31, 2015 and 2014 the gross carrying value of the Company’s Properties was as follows (in thousands): 2015 2014 Land $ 513,268 $ 669,635 Building and improvements 2,719,780 3,409,303 Tenant improvements 459,952 524,754 3,693,000 4,603,692 Assets held for sale - real estate investments (a) 794,588 27,436 Total $ 4,487,588 $ 4,631,128 (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
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 The purchase price is allocated as follows: December 19, 2013 Building, land and improvements $ 255,705 Intangible assets acquired 85,036 Below market lease liabilities assumed (8,637 ) $ 332,104 Mortgage debt assumed - at fair value (a) (238,082 ) Return of existing equity method investment (30,424 ) Net working capital assumed 10,423 Non-controlling interest (946 ) Total cash payment at settlement $ 73,075 (a) Principal outstanding on assumed mortgage debt at December 19, 2013 was $237.1 million.
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 )
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination	Intangible assets acquired and intangible liabilities assumed consist of the following (in thousands): December 19, 2013 Weighted Average Amortization Period (in years) Intangible assets: In-place lease value $ 80,916 7.9 Above market tenant leases acquired 4,120 6.9 Total $ 85,036 Intangible liabilities: Below market leases acquired $ (8,637 ) 6.5
Held for Sale Properties Included in Continuing Operations [Member]
Real Estate Properties [Line Items]
Summary of Properties Classified as Held for Sale but Which did not Meet the Criteria to be Classified within Discontinued Operations	The following is a summary of properties classified as held for sale but which did 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, net 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.
Office Properties [Member]
Real Estate Properties [Line Items]
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 Newark, DE / 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 Poperties) 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/(Loss) 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. The Company sold the following office properties during the twelve-month period ended December 31, 2013 (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) December 19, 2013 875 First Avenue King of Prussia, PA 1 50,000 $ 3,750 $ 3,658 $ 131 October 17, 2013 1336 Enterprise Drive West Chester, PA 1 39,330 2,600 2,521 156 October 16, 2013 Austin Properties/DRA JV Austin, TX 7 1,398,826 330,000 266,340 25,864 (b) June 28, 2013 16870 West Bernardo Drive San Diego, CA 1 68,708 18,000 17,403 (856 ) June 28, 2013 100 Arrandale Boulevard Exton, PA 1 34,931 3,500 3,268 (401 ) June 19, 2013 1700 Paoli Pike (100 Applebrook) Malvern, PA 1 28,000 2,675 2,544 (444 ) June 14, 2013 Pacific View Plaza Carlsbad, CA 1 51,695 10,300 9,950 (521 ) February 25, 2013 Princeton Pike Corporate Center Lawrenceville, NJ 8 800,546 121,000 112,863 5,304 Total Dispositions 21 2,472,036 $ 491,825 $ 418,547 $ 29,233 (a) Gain/(Loss) on Sale is net of closing and other transaction related costs. (b) The Austin portfolio was contributed to a newly formed real estate venture. For additional information, see Note 4, “ Investments in Unconsolidated Ventures

Investment in Unconsolidated 38

Investment in Unconsolidated Ventures (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 and 2014, and the Company’s share of the Real Estate Ventures’ income (loss) for the years ended December 31, 2015 and 2014 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) 2015 2014 2015 2014 2015 2014 Current Interest Rate Debt Maturity Office Properties Brandywine-AI Venture LLC 50% $ 50,760 $ 45,712 $ (229 ) $ (185 ) $ 132,717 $ 133,843 3.94 % (c) DRA (G&I) Austin (b) 50% 60,427 40,374 (1,235 ) (574 ) 410,066 382,100 3.38 % (d) 1000 Chesterbrook Blvd. 50% 1,895 2,152 117 388 23,610 24,251 4.75 % Dec 2021 Four Tower Bridge 65% 1,684 1,474 211 (144 ) 10,162 10,353 5.20 % Feb 2021 PJP VII 25% 872 911 211 177 5,621 5,785 L+2.65% Dec 2019 PJP II 30% 435 403 32 73 3,201 3,492 6.12 % Nov 2023 PJP V 25% 305 216 189 166 5,035 5,242 6.47 % Aug 2019 PJP VI 25% 45 45 151 (67 ) 7,918 8,168 6.08 % Apr 2023 Invesco, L.P. (h) - - 349 989 - - Broadmoor Austin Associates (h) - 65,407 (377 ) (460 ) - 53,516 G&I Interchange Office LLC (DRA-N. PA) (h) - - - (658 ) - 174,595 Coppell Associates (e) 50% (1,130 ) (1,214 ) 84 (45 ) 15,515 15,747 5.75 % Feb 2016 Other HSRE-Campus Crest IX, LLC (b) 30% 15,003 14,314 (188 ) 67 95,562 90,245 L+2.20% Jul 2016 4040 Wilson 50% 36,626 27,415 (106 ) (132 ) - - TB-BDN Plymouth Apartments 50% 12,338 12,720 (252 ) (83 ) 50,964 29,481 L+1.70% Dec 2017 Residence Inn Tower Bridge (h) - 723 367 107 - 13,394 Development Properties Brandywine 1919 Ventures (b) (f) 50% 29,086 12,823 - (21 ) 19,411 - L+2.25% Oct 2018 51 N Street 70% 16,725 - - - - - 1250 First Street Office 70% 14,312 - - - - - Seven Tower Bridge 20% 491 315 (135 ) (388 ) 14,789 14,865 3.44 % (g) $ 239,874 $ 223,790 $ (811 ) $ (790 ) $ 794,571 $ 965,077 (a) Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable. (b) 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). (c) The debt for these properties is comprised of three fixed rate mortgages: (1) $38.8 million with a 4.40% fixed interest rate due January 1, 2019, (2) $27.6 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 3.94%. (d) The debt for these properties includes seven mortgages: (1) $34.0 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) $55.8 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) $140.3 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) $34.5 million with a 3.87% fixed interest rate due August 6, 2019, (6) $86.4 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 28, 2020, and (7) $30.0 million with a rate of LIBOR + 1.85% with a cap of 2.75%, resulting in a time and dollar weighted average rate of 3.38%. (e ) Carrying amount represents the negative investment balance of the venture and is included in other liabilities. ( f ) The stated rate for the construction loan is LIBOR + 2.25%. The interest rate spread decreases to 2.00% upon receipt of certificate of occupancy. It is further reduced to 1.75% upon stabilization. To fulfill interest rate protection requirements an interest rate cap was purchased at 4.50%. (g ) 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 $0.9 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, 2016 maturity and a $3.9 million 3.00% 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 3.4%. (h ) The ownership interest in Invesco, L.P. was sold prior to December 31, 2014. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in DRA-N. PA was disposed of on August 12, 2015.
Summary of Financial Position of Real Estate Ventures	The following is a summary of the financial position of the Real Estate Ventures as of December 31, 2015 and December 31, 2014 (in thousands): December 31, 2015 December 31, 2014 Net property $ 1,258,999 $ 1,281,282 Other assets 158,672 195,121 Other liabilities 68,028 68,481 Debt 794,571 965,077 Equity 554,072 442,845 Company’s share of equity (Company’s basis) (a) (b) $ 241,004 $ 225,004 (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 and $1.2 million as of December 31, 2015 and 2014, respectively, which is included in other liabilities.
Summary of Results of Operations of Real Estate Ventures with Interests	The following is a summary of results of operations of the Real Estate Ventures in which the Company had interests as of December 31, 2015, 2014 and 2013 (in thousands): Years ended December 31, 2015 2014 2013 Revenue $ 164,928 $ 147,236 $ 102,919 Operating expenses (70,136 ) (61,268 ) (40,436 ) Interest expense, net (34,584 ) (36,511 ) (26,529 ) Depreciation and amortization (68,100 ) (57,109 ) (35,138 ) Net income (loss) $ (7,892 ) $ (7,652 ) $ 816 Company’s share of income (loss) (Company’s basis) $ (811 ) $ (790 ) $ 3,664
Schedule of Maturities of Long-term Debt	As of December 31, 2015, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2016 $ 249,468 2017 333,682 2018 340,437 2019 16,768 2020 17,661 Thereafter 1,458,208 Total principal payments 2,416,224 Net unamortized premiums/(discounts) (8,912 ) Net deferred financing costs (22,595 ) Outstanding indebtedness $ 2,384,717
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Schedule of Maturities of Long-term Debt	As of December 31, 2015, the aggregate principal payments of recourse and non-recourse debt payable to third-parties are as follows (in thousands): 2016 $ 120,811 2017 68,319 2018 244,403 2019 175,975 2020 92,761 Thereafter 92,302 $ 794,571

Deferred Costs (Assets) (Tables

Deferred Costs (Assets) (Tables)	12 Months Ended
	Dec. 31, 2015
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure	As of December 31, 2015 and 2014, the Company’s deferred costs (assets) were comprised of the following (in thousands): December 31, 2015 Total Cost Amortization Deferred Costs, net Leasing costs $ 165,741 $ (67,342 ) $ 98,399 Financing costs - Revolving Credit Facility (a) 3,578 (558 ) 3,020 Total $ 169,319 $ (67,900 ) $ 101,419 December 31, 2014 Total Cost Accumulated Amortization Deferred Costs, net Leasing costs $ 164,081 $ (64,065 ) $ 100,016 Financing costs - Revolving Credit Facility (a) 4,588 (3,343 ) 1,245 Total $ 168,669 $ (67,408 ) $ 101,261 (a) During the fourth quarter of 2015, the Company adopted accounting guidance related to the presentation of deferred financing costs on the balance sheet and reclassified amounts from the deferred costs line to net against the debt liability for all periods presented. Only deferred financing costs associated with our credit facility remain in deferred costs (assets) on the consolidated balance sheets. See Note 2, “ Summary of Significant Accounting Policies,”

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Intangible Assets	As of December 31, 2015 and 2014, the Company’s intangible assets were comprised of the following (in thousands): 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 December 31, 2014 Total Cost Accumulated Amortization Intangible Assets, net Intangible assets, net: In-place lease value $ 129,411 $ (42,068 ) $ 87,343 Tenant relationship value 34,172 (26,344 ) 7,828 Above market leases acquired 5,641 (1,409 ) 4,232 Total intangible assets, net $ 169,224 $ (69,821 ) $ 99,403 Acquired lease intangibles, net: Below market leases acquired $ 53,049 $ (27,039 ) $ 26,010
Summary of Amortization for Intangible Assets and Liabilities	As of December 31, 2015, the Company’s annual amortization for its intangible assets/liabilities, assuming no early lease terminations, are as follows (in thousands): Assets Liabilities 2016 $ 36,635 $ 7,595 2017 19,814 3,461 2018 12,587 2,217 2019 11,288 1,885 2020 9,149 1,337 Thereafter 22,731 9,352 112,204 25,847 Assets held for sale (581 ) (192 ) Total $ 111,623 $ 25,655

Debt Obligations (Tables)

Debt Obligations (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Consolidated debt obligations	The following table sets forth information regarding the Company’s consolidated debt obligations outstanding at December 31, 2015 and 2014 (in thousands): December 31, 2015 December 31, 2014 Effective Interest Rate Maturity Date MORTGAGE DEBT: Tysons Corner $ - $ 89,513 5.36 % Oct 2015 (a) Two Logan Square 86,886 87,767 7.57 % Apr 2016 Fairview Eleven Tower (b) 20,838 21,242 4.25 % Jan 2017 One Commerce Square 130,000 123,205 3.64 % (c) Apr 2023 Two Commerce Square 112,000 112,000 4.51 % (d) Apr 2023 IRS Philadelphia Campus (e) 177,425 184,442 7.00 % Sep 2030 Cira South Garage (e) 35,546 37,765 7.12 % Sep 2030 Principal balance outstanding 562,695 655,934 Plus: fair market value premium (discount), net (3,198 ) (1,344 ) Less: deferred financing costs (13,744 ) (14,959 ) Mortgage indebtedness $ 545,753 $ 639,631 UNSECURED DEBT Seven-Year Term Loan - Swapped to fixed $ 250,000 $ 200,000 3.72 % (f) Oct 2022 $250.0M 6.00% Guaranteed Notes due 2016 149,919 149,919 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 1,853,529 1,803,529 Plus: original issue premium (discount), net (5,714 ) (6,811 ) Less: deferred financing costs (8,851 ) (9,004 ) Total unsecured indebtedness $ 1,838,964 $ 1,787,714 Total Debt Obligations $ 2,384,717 $ 2,427,345 ( a ) On August 19, 2015, the Company entered into a forbearance agreement to extend the maturity date of the mortgage note payable collateralized by two of its properties located at 8260 Greensboro Drive and 1676 International Drive in Mclean, Virginia (referred to as "Tysons Corner" above). On October 9, 2015, the Company funded $88.4 million, including $0.4 million of accrued interest, in repayment of the Tysons Corner mortgage note with funds from the additional borrowings under the seven-year term loan referenced below. (b ) Represents the full debt amount of a property in a consolidated real estate venture for which the Company maintains a 50% interest. ( 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 ) Mortgage debt was prepaid prior to the scheduled maturity. See Note 21, “Subsequent Events,”
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) Gain (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 During the year-ended December 31, 2013, the Company repurchased $29.3 million of its outstanding unsecured Notes in a series of transactions that are summarized in the following table (in thousands): Notes Principal Repurchase Amount (a) Gain (Loss) on Early Extinguishment of Debt (b) Acceleration of Deferred Financing 2014 5.40% Notes $ 19,830 $ 20,853 $ (1,020 ) $ 16 2015 7.50% Notes 8,910 9,945 (1,036 ) 23 2016 6.00% Notes 510 571 (63 ) 1 $ 29,250 $ 31,369 $ (2,119 ) $ 40 (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, 2015, the Company’s aggregate scheduled principal payments of debt obligations, excluding amortization of discounts and premiums, are as follows (in thousands): 2016 $ 249,468 2017 333,682 2018 340,437 2019 16,768 2020 17,661 Thereafter 1,458,208 Total principal payments 2,416,224 Net unamortized premiums/(discounts) (8,912 ) Net deferred financing costs (22,595 ) Outstanding indebtedness $ 2,384,717

Fair Value of Financial Instr42

Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 December 31, 2014 Carrying Amount Fair Value Carrying Amount Fair Value Unsecured notes payable $ 1,512,554 $ 1,529,346 $ 1,510,181 $ 1,593,212 Variable rate debt $ 326,410 $ 305,522 $ 277,533 $ 257,188 Mortgage notes payable (a) $ 545,753 $ 597,377 $ 639,631 $ 707,241 Mortgage note receivable (b) $ - $ - $ 88,000 $ 87,692 (a) The IRS Philadelphia Campus mortgage debt and Cira South Garage mortgage debt were prepaid prior to their scheduled maturity. See Note 21, “Subsequent Events,” (b) See Note 2, “ Summary of Significant Accounting Policies - Notes Receivable

Risk Management and Use of Fi43

Risk Management and Use of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 and December 31, 2014. 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 liabilities on the Company’s consolidated balance sheets). Hedge Product Hedge Type Designation Notional Amount Strike Trade Date Maturity Date Fair value 12/31/2015 12/31/2014 12/31/2015 12/31/2014 Assets Swap Interest Rate Cash Flow (a), (b) $ 250,000 $ - 3.718 % October 8, 2015 October 8, 2022 $ 1,884 $ - Liabilities Swap Interest Rate Cash Flow (a), (b) $ - $ 200,000 3.623 % December 6-13, 2011 February 1, 2019 $ - $ (2,649 ) Swap Interest Rate Cash Flow (a) 25,774 25,774 3.300 % December 22, 2011 January 30, 2021 (531 ) (334 ) Swap Interest Rate Cash Flow (a) 25,774 25,774 3.090 % January 6, 2012 October 30, 2019 (388 ) (254 ) Swap Interest Rate Cash Flow (a) 27,062 27,062 2.750 % December 21, 2011 September 30, 2017 (201 ) (253 ) $ 328,610 $ 278,610 (a) Hedging unsecured variable rate debt. (b) On October 8, 2015, the Company amended its $200.0 million seven-year term loan maturing February 1, 2019, increasing the term loan by an additional $50.0 million and lengthening the maturity date to October 8, 2022 (See Note 7, “ Debt Obligations

Discontinued Operations (Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2013 (in thousands): Years ended December 31, 2014 2013 Revenue: Rents $ - $ 4,754 Tenant reimbursements 26 355 Other - 123 Total revenue 26 5,232 Expenses: Property operating expenses 8 1,839 Real estate taxes - 649 Depreciation and amortization - 1,921 Total operating expenses 8 4,409 Other income: Interest income - 2 Income from discontinued operations before gain on sale of interests in real estate 18 825 Net gain on disposition of discontinued operations 900 3,382 Income from discontinued operations $ 918 $ 4,207

Beneficiaries Equity of the P45

Beneficiaries Equity of the Parent Company (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 2014 2013 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 $ 38,982 $ 38,982 Net income (loss) from continuing operations attributable to non-controlling interests 339 339 43 43 (357 ) (357 ) Nonforfeitable dividends allocated to unvested restricted shareholders (329 ) (329 ) (349 ) (349 ) (363 ) (363 ) Preferred share dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Income (loss) from continuing operations available to common shareholders (37,630 ) (37,630 ) (1,182 ) (1,182 ) 31,362 31,362 Income from discontinued operations - - 908 908 4,152 4,152 Net income (loss) attributable to common shareholders $ (37,630 ) $ (37,630 ) $ (274 ) $ (274 ) $ 35,514 $ 35,514 Denominator Weighted-average shares outstanding 178,162,160 178,162,160 166,202,649 166,202,649 153,140,458 153,140,458 Contingent securities/Share based compensation - - - - - 1,273,853 Weighted-average shares outstanding 178,162,160 178,162,160 166,202,649 166,202,649 153,140,458 154,414,311 Earnings (loss) per Common Share: Income (loss) from continuing operations attributable to common shareholders $ (0.21 ) $ (0.21 ) $ (0.01 ) $ (0.01 ) $ 0.20 $ 0.20 Discontinued operations attributable to common shareholders - - 0.01 0.01 0.03 0.03 Net income (loss) attributable to common shareholders $ (0.21 ) $ (0.21 ) $ - $ - $ 0.23 $ 0.23

Partners Equity of the Operat46

Partners Equity of the Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
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, 2015 2014 2013 Basic Diluted Basic Diluted Basic Diluted Numerator Income (loss) from continuing operations $ (30,740 ) $ (30,740 ) $ 6,024 $ 6,024 $ 38,982 $ 38,982 Nonforfeitable dividends allocated to unvested restricted unitholders (329 ) (329 ) (349 ) (349 ) (363 ) (363 ) Preferred unit dividends (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) (6,900 ) Net loss attributable to non-controlling interests 3 3 44 44 - - Income (loss) from continuing operations available to common unitholders (37,966 ) (37,966 ) (1,181 ) (1,181 ) 31,719 31,719 Discontinued operations attributable to common unitholders - - 918 918 4,207 4,207 Net income (loss) attributable to common unitholders $ (37,966 ) $ (37,966 ) $ (263 ) $ (263 ) $ 35,926 $ 35,926 Denominator Weighted-average units outstanding 179,697,262 179,697,262 167,942,246 167,942,246 154,929,545 154,929,545 Contingent securities/Share based compensation - - - - - 1,273,853 Total weighted-average units outstanding 179,697,262 179,697,262 167,942,246 167,942,246 154,929,545 156,203,398 Earnings (loss) per Common Partnership Unit: Income (loss) from continuing operations attributable to common unitholders (0.21 ) (0.21 ) (0.01 ) (0.01 ) 0.20 0.20 Discontinued operations attributable to common unitholders - - 0.01 0.01 0.03 0.03 Net income (loss) attributable to common unitholders $ (0.21 ) $ (0.21 ) $ - $ - $ 0.23 $ 0.23

Share Based Compensation, 40147

Share Based Compensation, 401(k) Plan and Deferred Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Option Activity	Option activity as of December 31, 2015 and changes during the year-ended December 31, 2015 were as follows: Shares Weighted Average Exercise Price Weighted Average Remaining Contractual Term (in years) Aggregate Intrinsic Value Outstanding at January 1, 2015 2,684,795 $ 15.55 4.10 Exercised (10,728 ) $ 11.89 $ 18,989 Forfeited/Expired (50,000 ) $ 20.61 Outstanding at December 31, 2015 2,624,067 $ 15.47 3.12 - Vested/Exercisable at December 31, 2015 2,624,067 $ 15.47 3.12 -
Company's Restricted Share Activity	The following table summarizes the Company’s restricted share activity during the year-ended December 31, 2015: Shares Weighted Average Grant Date Fair Value Aggregate Intrinsic Value Non-vested at January 1, 2015 540,066 $ 12.21 Granted 186,791 15.67 $ 2,927,538 Vested (219,312 ) 11.78 $ 3,272,381 Forfeited (1,398 ) 14.33 Non-vested at December 31, 2015 506,147 $ 14.50 $ 6,913,968
Schedule of Restricted Performance Share Units Plan	The table below presents certain information as to unvested RPSU awards. RPSU Grant 2/25/2013 3/11/2014 3/12/2014 2/23/2015 Total (Amounts below in shares, unless otherwise noted) Non-vested at January 1, 2015 199,577 130,717 61,720 - 392,014 Units Granted - - - 186,395 186,395 Units Accelerated for Qualifying Retirement (8,255 ) (7,562 ) - (7,003 ) (22,820 ) Non-vested at December 31, 2015 191,322 123,155 61,720 179,392 555,589 Measurement Period Commencement Date 1/1/2013 1/1/2014 1/1/2014 1/1/2015 Measurement Period End Date 12/31/2015 12/31/2016 12/31/2016 12/31/2017 Units Granted 231,093 134,284 61,720 186,395 Fair Value of Units on Grant Date (in thousands) $ 4,137 $ 2,624 $ 1,225 $ 3,933

Distributions (Tables)

Distributions (Tables)	12 Months Ended
	Dec. 31, 2015
Distributions [Abstract]
Schedule of Dividends Payable	The following table provides the tax characteristics of the 2015, 2014 and 2013 distributions: Years ended December 31, 2015 2014 2013 (in thousands, except per share amounts) Common Share Distributions: Ordinary income $ 0.36 $ 0.41 $ 0.52 Capital gain 0.14 0.02 - Non-taxable distributions 0.10 0.17 0.08 Distributions per share $ 0.60 $ 0.60 $ 0.60 Percentage classified as ordinary income 59.10 % 69.00 % 87.00 % Percentage classified as capital gain 23.50 % 3.30 % -% Percentage classified as non-taxable distribution 17.40 % 27.70 % 13.00 % Preferred Share Distributions: Total distributions declared $ 6,900 $ 6,900 $ 6,900 Percentage classified as ordinary income 100.00 % 100.00 % 100.00 %

Accumulated Other Comprehensi49

Accumulated Other Comprehensive Income (Loss) (Tables)	12 Months Ended
	Dec. 31, 2015
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, 2015 (in thousands): Parent Company Cash Flow Hedges Balance at January 1, 2013 $ (15,918 ) Change during year 12,789 Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests (152 ) Reclassification adjustments for (gains)/losses reclassified into operations 286 Balance at December 31, 2013 $ (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 ) Operating Partnership Cash Flow Hedges Balance at January 1, 2013 $ (16,452 ) Change during year 12,789 Reclassification adjustments for (gains)/losses reclassified into operations 286 Balance at December 31, 2013 $ (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 )

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Schedule 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, 2015, 2014 and 2013 (in thousands): Real estate investments, at cost: December 31, 2015 December 31, 2014 December 31, 2013 Philadelphia CBD (a) $ 1,157,667 $ 1,338,655 $ 1,300,666 Pennsylvania Suburbs (b) 1,019,280 1,178,470 1,199,105 Metropolitan Washington, D.C. (b) 1,129,206 1,183,652 1,214,965 New Jersey/Delaware (b) 154,326 392,581 414,716 Richmond, Virginia (b) - 317,076 310,397 California 68,003 193,258 192,584 Austin, Texas (c) 164,518 - 36,856 $ 3,693,000 $ 4,603,692 $ 4,669,289 Assets held for sale (a), (b) 794,588 27,436 - Operating Properties $ 4,487,588 $ 4,631,128 $ 4,669,289 Corporate Construction-in-progress $ 268,983 $ 201,360 $ 74,174 Land inventory $ 130,479 $ 90,603 $ 93,351 ( a) 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. ( b ) As of December 31, 2015, the 58 properties associated with the transaction 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 21, “Subsequent Events,” The sale is not classified as a significant disposition under the accounting guidance for discontinued operations ( c ) 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, 2015. See Note 3, "Real Estate Investments,"
Schedule of Segment Net Operating Income, by Segment	Years ended December 31, 2015 2014 2013 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 $ 209,298 $ (77,352 ) $ 131,946 $ 201,809 $ (75,262 ) $ 126,547 $ 146,081 $ (55,702 ) $ 90,379 Pennsylvania Suburbs 158,398 (57,319 ) 101,079 160,630 (55,062 ) 105,568 153,426 (54,506 ) 98,920 Metropolitan Washington, D.C. 110,657 (44,294 ) 66,363 113,834 (43,399 ) 70,435 116,048 (42,641 ) 73,407 New Jersey/Delaware 47,726 (26,854 ) 20,872 60,403 (31,650 ) 28,753 60,262 (29,981 ) 30,281 Richmond, Virginia 36,486 (15,073 ) 21,413 34,180 (15,399 ) 18,781 35,058 (14,916 ) 20,142 California 14,587 (7,677 ) 6,910 19,388 (10,165 ) 9,223 18,369 (9,411 ) 8,958 Austin, Texas (b) 20,910 (8,010 ) 12,900 5,610 (3,223 ) 2,387 31,451 (13,298 ) 18,153 Corporate 4,569 (1,508 ) 3,061 1,128 (1,805 ) (677 ) 1,515 (1,314 ) 201 Operating Properties $ 602,631 $ (238,087 ) $ 364,544 $ 596,982 $ (235,965 ) $ 361,017 $ 562,210 $ (221,769 ) $ 340,441 (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, 2015. See Note 3, "Real Estate Investments,"
Schedule of Segment Reporting Information, by Segment	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, 2015 December 31, 2014 December 31, 2013 2015 2014 2013 Philadelphia CBD (a) $ 44,089 $ 27,137 $ 19,975 $ (188 ) $ 46 $ 1,547 Pennsylvania Suburbs 16,408 17,385 17,272 310 (777 ) 925 Metropolitan Washington, D.C. (b) 118,422 73,127 59,905 (336 ) (317 ) 130 New Jersey/Delaware - - - 348 989 1,245 Richmond, Virginia 1,657 1,574 1,400 582 349 381 Austin, Texas (c) (d) 60,428 105,781 81,960 (1,527 ) (1,080 ) (564 ) Total $ 241,004 $ 225,004 $ 180,512 $ (811 ) $ (790 ) $ 3,664 (a) evo at Cira was placed into service during the third quarter ended September 30, 2014. (b) Investment in real estate ventures as of December 31, 2015 includes the JBG Ventures, which were formed on May 29, 2015. (c) Investment in real estate ventures does not include the $1.1 million and $1.2 million negative investment balance in one real estate venture as of December 31, 2015 and December 31, 2014, respectively, which is included in other liabilities. ( d ) On June 22, 2015 the Company acquired the remaining 50.0% of the common interest in Broadmoor Austin Associates. As such, the equity method investment at December 31, 2015 related to the Austin Venture only. See Note 3, " Real Estate Investments ," for further information regarding the purchase of Broadmoor Austin Associates.
Reconciliation of Consolidated Net Operating Income	The following is a reconciliation of consolidated NOI to consolidated net income, as defined by GAAP: Years Ended December 31, 2015 2014 2013 Consolidated net operating income $ 364,544 $ 361,017 $ 340,441 Less: Interest expense (110,717 ) (124,329 ) (121,937 ) Interest expense - amortization of deferred financing costs (4,557 ) (5,148 ) (4,676 ) Interest expense - financing obligation (1,237 ) (1,144 ) (972 ) Depreciation and amortization (219,029 ) (208,569 ) (197,021 ) General and administrative expenses (29,406 ) (26,779 ) (27,628 ) Equity in income (loss) of real estate ventures (811 ) (790 ) 3,664 Provision for impairment (82,208 ) (1,765 ) - Plus: Interest income 1,224 3,974 1,044 Tax credit transaction income 19,955 11,853 11,853 Recognized hedge activity - (828 ) - Net gain from remeasurement of investments in real estate ventures 758 458 6,866 Net gain on sales of interests in real estate 20,496 4,901 - Net gain (loss) on sale of undepreciated real estate 3,019 1,184 (137 ) Net gain (loss) on real estate venture transactions 7,229 (417 ) 29,604 Loss on early extinguishment of debt - (7,594 ) (2,119 ) Income (loss) from continuing operations (30,740 ) 6,024 38,982 Income from discontinued operations - 918 4,207 Net income (loss) $ (30,740 ) $ 6,942 $ 43,189

Operating Leases (Tables)

Operating Leases (Tables)	12 Months Ended
	Dec. 31, 2015
Leases Operating [Abstract]
Operating Leases Future Minimum Payments Receivable	The Company leases properties to tenants under operating leases with various expiration dates extending to 2030. Minimum future rentals on non-cancelable leases at December 31, 2015 are as follows (in thousands): Year Minimum Rent 2016 $ 448,798 2017 425,828 2018 394,055 2019 349,315 2020 307,163 Thereafter 1,500,760

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments And Contingencies Disclosure [Abstract]
Contractual Leases Obligation Future Minimum Payments Due	Minimum future rental payments on non-cancelable leases at December 31, 2015 are as follows (in thousands): Year Minimum Rent 2016 $ 1,385 2017 1,385 2018 1,385 2019 1,385 2020 1,385 Thereafter 67,229 Total $ 74,154

Summary of Quarterly Results (T

Summary of Quarterly Results (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	The following is a summary of quarterly financial information as of and for the years ended December 31, 2015 and 2014 (in thousands, except per share data): 1st 2nd 3rd 4th Quarter Quarter Quarter Quarter 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 ) 2014 Total revenue $ 152,114 $ 150,500 $ 146,558 $ 147,810 Net income (loss) (2,245 ) 2,174 8,882 (1,869 ) Net income (loss) allocated to Common Shares (4,041 ) 385 6,967 (3,585 ) Basic earnings (loss) per Common Share $ (0.03 ) $ - $ 0.04 $ (0.02 ) Diluted earnings (loss) per Common Share $ (0.03 ) $ - $ 0.04 $ (0.02 )

Organization of The Parent Co54

Organization of The Parent Company and The Operating Partnership (Textual) (Details) ft² in Millions	Dec. 31, 2015ft²apropertyReal_Estate_Investments
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	179
Och Ziff Properties [Member] | Held for Sale Properties Included in Continuing Operations [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	59
Office Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	106
Industrial Facilities [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	6
Mixed Use Properties [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	3
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	116
Development Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	2
Redevelopment Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	1
Re-entitlement Property [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Number of Properties	1
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	23
Area Owned by Company of Undeveloped Parcels Of Land | a	412
Area Of Additional Undeveloped Parcels Of Land With Option to Purchase | a	50
Total Potential Development Capacity | ft²	7.1
Undeveloped Land Held for Sale. | a	120
Unconsolidated Real Estate Ventures [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	4.3
Number of Unconsolidated Real Estate Ventures | Real_Estate_Investments	16
Subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Ownership in the Operating Partnership	100.00%
Wholly-owned Management Company Subsidiaries [Member]
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	29.5
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	23
Wholly-owned Management Company Subsidiaries [Member] | Partially Owned Properties
Organization of The Parent Company and The Operating Partnership [Line Items]
Net Rentable Square Feet | ft²	6.5

Summary of Significant Accoun55

Summary of Significant Accounting Policies (Textual) (Details)	12 Months Ended
	Dec. 31, 2015USD ($)Customershares	Dec. 31, 2014USD ($)Customer	Dec. 31, 2013USD ($)Customer	Jun. 02, 2010shares
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Revenue increased by straight-line rent adjustment	$ 21,600,000	$ 13,700,000	$ 17,700,000
Increased revenue due to amortization of deferred rent	2,000,000	2,400,000	2,400,000
Decrease in revenue due to amortization of lease incentives	$ 1,800,000	1,500,000	700,000
Common shares available for future awards | shares	4,295,559
Increase in Common shares available for future awards | shares				6,000,000
Stock-based compensation expense	$ 7,300,000	6,100,000	8,300,000
Stock-based compensation expense, capitalized	1,900,000	1,700,000	1,400,000
Variable interest entity, assets	422,900,000
Variable interest entity, liabilities	$ 258,200,000
Employee Stock Option And Share Appreciation Rights
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Common shares available for future awards | shares	2,624,067			3,600,000
Options [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Stock-based compensation expense	$ 0	0	700,000
Stock-based compensation expense, capitalized	$ 0	$ 0	$ 100,000
Customer Concentration Risk [Member] | Rental Revenue [Member]
Summary Of Significant Accounting Policies (Textuals) [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 (Textuals) [Abstract]
Property, Plant and Equipment, Useful Life	55 years
Tenant Improvements Useful Lives	16 years
Maximum [Member] | Options [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Share based compensation, term	10 years
Minimum [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Property, Plant and Equipment, Useful Life	5 years
Tenant Improvements Useful Lives	1 year
Minimum [Member] | Options [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Share based compensation, term	1 year
The Grove at Cira Centre South [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Guarantor obligations, current carrying value	$ 24,700,000
TB-BDN Plymouth Apartments [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Guarantor obligations, current carrying value	3,200,000
PJP VII [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Guarantor obligations, current carrying value	500,000
Unconsolidated Real Estate Ventures [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Capitalized interest	2,000,000	$ 2,000,000	$ 600,000
1919 Venture [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Guarantor obligations, current carrying value	$ 88,900,000
New Accounting Pronouncement, Early Adoption Effect [Member]
Summary Of Significant Accounting Policies (Textuals) [Abstract]
Deferred financing costs reclassified from the deferred costs line and netted against the debt liability		$ 24,000,000

Summary of Significant Accoun56

Summary of Significant Accounting Policies - Construction in Progress (Textual) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Construction in Progress [Line Items]
Internal direct construction costs capitalized related to development of properties and land holdings	$ 7.3	$ 5.2	$ 3.7
Development [Member]
Construction in Progress [Line Items]
Capitalized interest	$ 10.2	$ 4.8	$ 2.6

Summary of Significant Accoun57

Summary of Significant Accounting Policies - Compensation Costs (Including Bonuses and Benefits) Capitalized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	$ 7,291	$ 5,194	$ 3,673
Development [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	2,641	1,749	156
Redevelopment [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	221	184	194
Tenant Improvements [Member]
Construction in Progress [Line Items]
Salaries including bonuses and benefits, capitalized during the period	$ 4,429	$ 3,261	$ 3,323

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Impairment or Disposal of Long-Lived Assets (Textual) (Details)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Disposition of assets, holding period	10 years

Summary of Significant Accoun59

Summary of Significant Accounting Policies - Accounts Receivable and Accrued Rent Receivable (Textual) (Details) $ in Millions	Dec. 31, 2015USD ($)Customer	Dec. 31, 2014USD ($)Customer
Tenant Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 1.7	$ 2
Accrued Rent Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for Doubtful Accounts Receivable	$ 14.5	$ 13.4
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 Accoun60

Summary of Significant Accounting Policies - Deferred Costs (Textual) (Details)	12 Months Ended
	Dec. 31, 2015
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Remaining Lease Period - Minimum	1 year
Remaining Lease Period - Maximum	15 years

Summary of Significant Accoun61

Summary of Significant Accounting Policies - Notes Receivable (Textual) (Details) - USD ($) $ in Thousands	Jan. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable		$ 0	$ 88,000
Proceeds from repayment of mortgage notes receivable		88,000	7,026	$ 200
Interest income		1,224	3,974	$ 1,044
River Place [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable			88,000
Proceeds from repayment of mortgage notes receivable	$ 88,000
Interest income		$ 400	$ 700

Summary of Significant Accoun62

Summary of Significant Accounting Policies - Income Taxes (Textual) (Details) - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Income Tax Contingency [Line Items]
Distributable Income Minimum Percentage	90.00%
Tax Basis of Assets, Cost for Income Tax Purposes	$ 3.9	$ 3.7
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	$ 3.9	$ 3.7

Real Estate Investments - Gross

Real Estate Investments - Gross Carrying Value of Company's Properties (Details) - USD ($) $ in Thousands	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Property, Plant and Equipment, Gross [Abstract]
Land	$ 513,268		$ 669,635
Building and improvements	2,719,780		3,409,303
Tenant improvements	459,952		524,754
Real Estate Investments	3,693,000		4,603,692		$ 4,669,289
Assets held for sale - real estate investments	794,588	[1]	27,436	[1]	$ 0
Total	$ 4,487,588		$ 4,631,128
[1]	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. 07, 2015USD ($)a	Jun. 22, 2015USD ($)ft²aproperty	May. 12, 2015USD ($)ft²	Apr. 06, 2015USD ($)a	Apr. 02, 2015USD ($)ft²	Feb. 19, 2014USD ($)ft²apropertyFloor	Dec. 19, 2013USD ($)ft²aStorey	Apr. 25, 2013USD ($)a	Dec. 31, 2015USD ($)ft²Storey	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Dec. 29, 2015USD ($)	Jun. 30, 2014USD ($)	Nov. 19, 2013USD ($)a
Business Acquisition [Line Items]
Rentable Square Feet | ft²										4,300,000
Ownership percentage	[1]									0.00%
Net gain from remeasurement of investments in real estate ventures										$ 758	$ 458	$ 6,866
Development in Progress										268,983	201,360
Change in operating real estate due to non-cash adjustment to land										0	0	$ 7,752
Secured Debt [Member]
Business Acquisition [Line Items]
Long-term Debt, Gross										$ 562,695	655,934
Encino Trace - Building I [Member]
Business Acquisition [Line Items]
Construction in Progress, Gross											38,800
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 Units in Real Estate Property | 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
Building, land and improvements			163,271
Business Combination, Cash Payment at Settlement			$ 143,821
A618 Market Street
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
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
Commerce Square [Member]
Business Acquisition [Line Items]
Acreage of Land | ft²								1,896,142
Percentage of ownership interests										99.00%
Lease percentage of acquired property												86.70%
Acquisition Costs								$ 900
Percent of Acquired Entity								99.00%
Consideration, Cash								$ 331,800
Building, land and improvements								255,705
Business Combination, Assumption of Existing Mortgage Debt								237,100
Business Combination, Cash Payment at Settlement								73,075
Net loss from remeasurement of investment in real estate ventures								1,000
One Commerce Square [Member] | Secured Debt [Member]
Business Acquisition [Line Items]
Long-term Debt, Gross								$ 125,100					$ 130,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate								5.67%
Long-term Debt, Fair Value								$ 130,200
Debt Instrument Maturity Date								Jan. 6, 2016		Apr. 5, 2023
Two Commerce Square [Member] | Secured Debt [Member]
Business Acquisition [Line Items]
Long-term Debt, Gross								$ 112,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate								3.96%
Long-term Debt, Fair Value								$ 107,900
Debt Instrument Maturity Date										Apr. 5, 2023
Four Points Centre [Member]
Business Acquisition [Line Items]
Acreage of Land | a								22.3
Rentable Square Feet | ft²								192,396
Lease percentage of acquired property								99.20%
Acquisition Costs								$ 100
Consideration, Cash								$ 47,300
Number of floors of a building | Storey								3
Business Acquisition Purchase Price Allocation Building								$ 36,000
Business Acquisition Purchase Price Allocation Land Portion								5,800
Business Acquisition Purchase Price Allocation Intangible Assets								6,500
Business Acquisition Purchase Price Allocated To Market Lease Liabilities								$ 1,000
Cira Ground Land Parcel [Member]
Business Acquisition [Line Items]
Acreage of Land | a															0.8
Acquisition Costs															$ 1,400
Ground Lease Buy-out, Total Cost															24,600
Accrued Rent															$ 12,100
Three Logan Square [Member]
Business Acquisition [Line Items]
Acreage of Land | a									1.8
Acquisition Costs									$ 100
Ground Lease Buy-out, Total Cost									20,800
Change in operating real estate due to non-cash adjustment to land									$ 4,300
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%
25 M Street [Member] | Jaco25 M Investors L L C
Business Acquisition [Line Items]
Payments to Acquire Land				$ 1,000
Asset Acquisition Ownership Percent				5.00%
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.

Real Estate Investments - Purch

Real Estate Investments - Purchase Price Allocation (Details) - USD ($) $ in Thousands		Jun. 22, 2015	Dec. 19, 2013
Broadmoor Austin Associates [Member]
Business Acquisition [Line Items]
Building, land and improvements		$ 163,271
Land inventory		6,045
Intangible assets acquired	[1]	50,637
Below market lease liabilities assumed	[2]	(8,600)
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
Commerce Square [Member]
Business Acquisition [Line Items]
Building, land and improvements			$ 255,705
Intangible assets acquired			85,036
Below market lease liabilities assumed			(8,637)
Total purchase price			332,104
Mortgage debt assumed - at fair value	[3]		(238,082)
Net working capital assumed			10,423
Non-controlling interest			(946)
Total cash payment at settlement			73,075
Return of existing equity method investment			$ (30,424)
[1]	Weighted average amortization period of 4.0 years.
[2]	Weighted average amortization period of 1.5 years
[3]	Principal outstanding on assumed mortgage debt at December 19, 2013 was $237.1 million.

Real Estate Investments - Pur66

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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings (loss) per common share from continuing operations:
Continuing operations (USD per share)									$ (0.21)	$ (0.01)	$ 0.20
Continuing operations (USD per share)									(0.21)	(0.01)	0.20
Earnings (loss) per common share:
Basic -- as reported	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	(0.21)	0	0.23
Diluted -- as reported	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	$ (0.21)	$ 0	$ 0.23
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:
Continuing operations (USD per share)									$ (0.17)	$ 0.04
Basic -- as pro forma									(0.21)	(0.04)
Continuing operations (USD per share)									(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)

Real Estate Investments - Summa

Real Estate Investments - Summary of Office Properties Sold (Details)		3 Months Ended		12 Months Ended
		Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)ft²property		Dec. 31, 2014USD ($)ft²property		Dec. 31, 2013USD ($)ft²property		Apr. 03, 2014property
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				179
Rentable Square Feet | ft²				4,300,000
Net Proceeds on Sale				$ 247,228,000		$ 118,855,000		$ 423,480,000
Gain (Loss) on Sale				$ 20,496,000		$ 4,901,000		$ 0
Encino Trace [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				2
Rentable Square Feet | ft²				320,000
Four Points Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								2		2
Rentable Square Feet | ft²								192,396
Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				27		8		21
Rentable Square Feet | ft²				2,649,926		645,273		2,472,036
Sales Price				$ 374,600,000		$ 101,150,000		$ 491,825,000
Net Proceeds on Sale				340,098,000		113,024,000		418,547,000
Gain (Loss) on Sale				$ 22,002,000	[1],[2]	$ 4,646,000	[3]	$ 29,233,000	[3]
Office Building [Member] | Encino Trace [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				2
Rentable Square Feet | ft²				320,000
Sales Price				$ 76,700,000
Net Proceeds on Sale				50,158,000
Gain (Loss) on Sale	[1],[4]			$ 2,008,000
Office Building [Member] | Laurel Corporate Center [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				6
Rentable Square Feet | ft²				560,147
Sales Price				$ 56,500,000
Net Proceeds on Sale				56,253,000
Gain (Loss) on Sale	[1]			$ 2,901,000
Office Building [Member] | Carlsbad Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				3
Rentable Square Feet | ft²				196,075
Sales Price				$ 30,400,000
Net Proceeds on Sale				29,568,000
Gain (Loss) on Sale	[1],[5]			$ 0
Office Building [Member] | 751-761 Fifth Ave [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				1
Rentable Square Feet | ft²				158,000
Sales Price				$ 4,600,000
Net Proceeds on Sale				4,245,000
Gain (Loss) on Sale	[1]			$ 894,000
Office Building [Member] | 1000 Howard Boulevard [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				1
Rentable Square Feet | ft²				105,312
Sales Price				$ 16,500,000
Net Proceeds on Sale				15,780,000
Gain (Loss) on Sale	[1]			$ 4,828,000
Office Building [Member] | Bay Colony Office Park [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				4
Rentable Square Feet | ft²				247,294
Sales Price				$ 37,500,000
Net Proceeds on Sale				36,386,000
Gain (Loss) on Sale	[1]			$ 269,000
Office Building [Member] | 741 First Avenue [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				1
Rentable Square Feet | ft²				77,184
Sales Price				$ 4,900,000
Net Proceeds on Sale				4,640,000
Gain (Loss) on Sale	[1]			$ 372,000
Office Building [Member] | 100 Gateway Centre Parkway [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				1
Rentable Square Feet | ft²				74,991
Sales Price				$ 4,100,000
Net Proceeds on Sale				3,911,000
Gain (Loss) on Sale		$ 0		$ 0	[1],[6]
Office Building [Member] | Christina & Delaware Corporate Centers [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				5
Rentable Square Feet | ft²				485,182
Sales Price				$ 50,100,000
Net Proceeds on Sale				49,579,000
Gain (Loss) on Sale	[1]			$ 1,749,000
Office Building [Member] | Lake Merritt Tower [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property				1
Rentable Square Feet | ft²				204,336
Sales Price				$ 65,000,000
Net Proceeds on Sale				62,800,000
Gain (Loss) on Sale			$ 0	$ 0	[1],[7]
Office Building [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 | property				2
Rentable Square Feet | ft²				221,405
Sales Price				$ 28,300,000
Net Proceeds on Sale				26,778,000
Gain (Loss) on Sale	[1]			$ 8,981,000
Office Building [Member] | 100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Poperties) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property						5
Rentable Square Feet | ft²						279,934
Sales Price						$ 37,900,000
Net Proceeds on Sale						37,156,000
Gain (Loss) on Sale	[3],[8]					$ 203,000
Office Building [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 | property						1
Rentable Square Feet | ft²						172,943
Sales Price						$ 42,500,000
Net Proceeds on Sale						41,476,000
Gain (Loss) on Sale	[3]					$ 4,698,000
Office Building [Member] | Four Points Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property						2
Rentable Square Feet | ft²						192,396
Sales Price						$ 20,750,000
Net Proceeds on Sale						34,392,000
Gain (Loss) on Sale	[3],[9]					$ (255,000)
Office Building [Member] | 875 First Avenue [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								1
Rentable Square Feet | ft²								50,000
Sales Price								$ 3,750,000
Net Proceeds on Sale								3,658,000
Gain (Loss) on Sale	[3]							$ 131,000
Office Building [Member] | 1336 Enterprise Drive [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								1
Rentable Square Feet | ft²								39,330
Sales Price								$ 2,600,000
Net Proceeds on Sale								2,521,000
Gain (Loss) on Sale	[3]							$ 156,000
Office Building [Member] | Austin Properties/ DRA JV [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								7
Rentable Square Feet | ft²								1,398,826
Sales Price								$ 330,000,000
Net Proceeds on Sale								266,340,000
Gain (Loss) on Sale	[3],[10]							$ 25,864,000
Office Building [Member] | 16870 West Bernardo [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								1
Rentable Square Feet | ft²								68,708
Sales Price								$ 18,000,000
Net Proceeds on Sale								17,403,000
Gain (Loss) on Sale	[3]							$ (856,000)
Office Building [Member] | 100 Arrandale Boulevard [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								1
Rentable Square Feet | ft²								34,931
Sales Price								$ 3,500,000
Net Proceeds on Sale								3,268,000
Gain (Loss) on Sale	[3]							$ (401,000)
Office Building [Member] | 1700 Paoli Pike (100 Applebrook) [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								1
Rentable Square Feet | ft²								28,000
Sales Price								$ 2,675,000
Net Proceeds on Sale								2,544,000
Gain (Loss) on Sale	[3]							$ (444,000)
Office Building [Member] | Pacific View Plaza [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								1
Rentable Square Feet | ft²								51,695
Sales Price								$ 10,300,000
Net Proceeds on Sale								9,950,000
Gain (Loss) on Sale	[3]							$ (521,000)
Office Building [Member] | Princeton Pike Corporate Center [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property								8
Rentable Square Feet | ft²								800,546
Sales Price								$ 121,000,000
Net Proceeds on Sale								112,863,000
Gain (Loss) on Sale	[3]							$ 5,304,000
[1]	Gain on Sale is net of closing and other transaction related costs.
[2]	Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale.
[3]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[4]	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.
[5]	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.
[6]	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.
[7]	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.
[8]	During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties.
[9]	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.
[10]	The Austin portfolio was contributed to a newly formed real estate venture. For additional information, see Note 4, “Investments in Unconsolidated Ventures,” to our consolidated financial statements.

Real Estate Investments - Sum69

Real Estate Investments - Summary of Office Properties Sold (Parenthetical) (Details)		Apr. 03, 2014USD ($)ft²propertyStorey	Dec. 31, 2015USD ($)ft²propertyStorey	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Sep. 30, 2014USD ($)	Dec. 31, 2015USD ($)ft²propertyStorey		Dec. 31, 2014USD ($)ft²property		Dec. 31, 2013USD ($)ft²propertyStorey		Dec. 30, 2015USD ($)	Oct. 17, 2014ft²property	Jul. 31, 2014ft²property	Oct. 16, 2013USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²			4,300,000				4,300,000
Number of Properties | property			179				179
Net gain (loss) on real estate venture transactions							$ 7,229,000		$ (417,000)		$ 29,604,000
Gain (Loss) on Sale							$ 20,496,000		$ 4,901,000		$ 0
Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²			2,649,926				2,649,926		645,273		2,472,036
Number of Properties | property			27				27		8		21
Gain (Loss) on Sale							$ 22,002,000	[1],[2]	$ 4,646,000	[3]	$ 29,233,000	[3]
Deferred gain			$ 500,000				$ 500,000
Encino Trace [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of floors of a building | Storey			4				4
Rentable Square Feet | ft²			320,000				320,000
Number of Properties | property			2				2
Encino Trace [Member] | Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²			320,000				320,000
Number of Properties | property			2				2
Gain (Loss) on Sale	[1],[4]						$ 2,008,000
Carlsbad, CA [Member] | Office Building [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
100 Gateway Centre Parkway [Member] | Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²			74,991				74,991
Number of Properties | property			1				1
Provision for impairment on assets held for sale				$ 800,000
Gain (Loss) on Sale				$ 0			$ 0	[1],[5]
Lake Merritt Tower [Member] | Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²			204,336				204,336
Number of Properties | property			1				1
Provision for impairment on assets held for sale					$ 1,700,000
Gain (Loss) on Sale					$ 0		$ 0	[1],[6]
100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Poperties) [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
100, 101, 200, 300 and 301 Lindenwood Drive (the Valleybrooke Poperties) [Member] | Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²									279,934
Number of Properties | property									5
Gain (Loss) on Sale	[3],[7]								$ 203,000
Four Points Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of floors of a building | Storey		3									3
Rentable Square Feet | ft²											192,396
Number of Properties | property		2									2
Four Points Centre [Member] | Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²									192,396
Number of Properties | property									2
Gain (Loss) on Sale	[3],[8]								$ (255,000)
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
Number of Properties | property														7	2
Austin Joint Venture [Member] | Encino Trace [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
Austin Joint Venture [Member] | Four Points Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Non-Recourse Debt		$ 29,000,000
Austin Joint Venture [Member] | Four Points Centre [Member] | Office Building [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²		192,396
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
Brandywine Realty Trust [Member] | Austin Joint Venture [Member] | Encino Trace [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Development costs													$ 76,700,000
Proceeds from Equity Method Investment, Dividends or Distributions							50,200,000
Capital contribution			23,300,000				23,300,000
Net 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
Brandywine Realty Trust [Member] | Austin Joint Venture [Member] | Four Points Centre [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Amount Of Participant Contribution		$ 5,900,000
Proceeds from Equity Method Investment, Dividends or Distributions		34,400,000
Net gain (loss) on real estate venture transactions									$ (200,000)
Aggregate gross sales price of a joint venture		$ 41,500,000
DRA Advisors LLC [Member] | Austin Joint Venture [Member] | Encino Trace [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
DRA Advisors LLC [Member] | Brandywine Realty Trust [Member] | Austin Joint Venture [Member] | Encino Trace [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
[1]	Gain on Sale is net of closing and other transaction related costs.
[2]	Total gain on sale does not include a deferred gain of $0.5 million related to a prior sale.
[3]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[4]	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.
[5]	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.
[6]	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.
[7]	During the third quarter of 2014, the Company recorded a $1.8 million impairment loss on these properties.
[8]	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 - Sum70

Real Estate Investments - Summary of Land Parcels Sold (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2015USD ($)aParcel		Dec. 31, 2014USD ($)aParcel		Dec. 31, 2013USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net Proceeds on Sale		$ 247,228		$ 118,855		$ 423,480
Gain (Loss) on Sale		$ 20,496		$ 4,901		$ 0
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		4		2
Acreage of Land | a		14.7		22.1
Sales Price		$ 22,300		$ 5,120
Net Proceeds on Sale		21,088		4,855
Gain (Loss) on Sale		$ 3,019	[1]	$ 1,184	[2]
Two Christina Centre [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		1
Acreage of Land | a		1.6
Sales Price		$ 6,500
Net Proceeds on Sale		5,986
Gain (Loss) on Sale	[1],[3]	$ 0
A7000 Midlantic [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		1
Acreage of Land | a		3.5
Sales Price		$ 2,200
Net Proceeds on Sale		1,742
Gain (Loss) on Sale	[1]	$ (169)
Four Points Centre [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		1
Acreage of Land | a		8.6
Sales Price		$ 2,500
Net Proceeds on Sale		2,344
Gain (Loss) on Sale	[1]	$ 71
Two Kaiser Plaza [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel		1
Acreage of Land | a		1
Sales Price		$ 11,100
Net Proceeds on Sale		11,016
Gain (Loss) on Sale	[1]	$ 3,117
West Point II Land [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				1
Acreage of Land | a				5.3
Sales Price				$ 1,600
Net Proceeds on Sale				1,505
Gain (Loss) on Sale	[2]			$ 12
Rob Roy - Land [Member] | Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel				1
Acreage of Land | a				16.8
Sales Price				$ 3,520
Net Proceeds on Sale				3,350
Gain (Loss) on Sale	[2]			$ 1,172
[1]	Gain/(Loss) on sale includes closing and other transaction related costs.
[2]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[3]	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 - Sum71

Real Estate Investments - Summary of Land Parcels Sold (Parenthetical) (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Dec. 31, 2015	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale			$ 20,496		$ 4,901		$ 0
Land [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain (Loss) on Sale			3,019	[1]	$ 1,184	[2]
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	[1],[3]		$ 0
Provision for impairment on assets held for sale		$ 300
[1]	Gain/(Loss) on sale includes closing and other transaction related costs.
[2]	Gain/(Loss) on Sale is net of closing and other transaction related costs.
[3]	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 - Sum72

Real Estate Investments - Summary of Properties Classified as Held for Sale Included in Continuing Operations (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
ASSETS HELD FOR SALE
Total assets held for sale, net		$ 584,365	$ 18,295
LIABILITIES HELD FOR SALE
Total liabilities held for sale		2,151	$ 602
Held for Sale Properties Included in Continuing Operations [Member]
ASSETS HELD FOR SALE
Operating properties		794,588
Accumulated depreciation		(213,581)
Operating real estate investments, net		581,007
Construction-in-progress		1,940
Land held for development		837
Total real estate investments, net		583,784
Intangible assets, net		581
Total assets held for sale, net		584,365
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net		192
Other liabilities		1,959
Total liabilities held for sale		2,151
Held for Sale Properties Included in Continuing Operations [Member] | Och Ziff Properties [Member]
ASSETS HELD FOR SALE
Operating properties	[1]	526,099
Accumulated depreciation	[1]	(179,092)
Operating real estate investments, net	[1]	347,007
Construction-in-progress	[1]	1,915
Land held for development	[1]	0
Total real estate investments, net	[1]	348,922
Intangible assets, net	[1]	581
Total assets held for sale, net	[1]	349,503
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net	[1]	192
Other liabilities	[1]	1,959
Total liabilities held for sale	[1]	2,151
Held for Sale Properties Included in Continuing Operations [Member] | 2970 Market Street [Member]
ASSETS HELD FOR SALE
Operating properties	[2]	268,489
Accumulated depreciation	[2]	(34,489)
Operating real estate investments, net	[2]	234,000
Construction-in-progress	[2]	25
Land held for development	[2]	0
Total real estate investments, net	[2]	234,025
Intangible assets, net	[2]	0
Total assets held for sale, net	[2]	234,025
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net	[2]	0
Other liabilities	[2]	0
Total liabilities held for sale	[2]	0
Held for Sale Properties Included in Continuing Operations [Member] | Greenhills Land [Member]
ASSETS HELD FOR SALE
Operating properties	[3]	0
Accumulated depreciation	[3]	0
Operating real estate investments, net	[3]	0
Construction-in-progress	[3]	0
Land held for development	[3]	837
Total real estate investments, net	[3]	837
Intangible assets, net	[3]	0
Total assets held for sale, net	[3]	837
LIABILITIES HELD FOR SALE
Acquired lease intangibles, net	[3]	0
Other liabilities	[3]	0
Total liabilities held for sale	[3]	$ 0
[1]	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.
[2]	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 our equity interests in Cira Square.
[3]	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 - Sum73

Real Estate Investments - Summary of Properties Classified as Held for Sale Included in Continuing Operations (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2015USD ($)ft²	Feb. 04, 2016ft²property	Jan. 15, 2016USD ($)Parcel	Dec. 23, 2015ft²
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²	4,300,000
Subsequent Event [Member]
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
Och Ziff Properties [Member] | Subsequent Event [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Rentable Square Feet | ft²		3,924,783
2970 Market Street [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
Greenhills Land [Member] | Subsequent Event [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Parcels | Parcel			120
Contractual Sales Price			$ 900,000

Real Estate Investments - Dispo

Real Estate Investments - Dispositions (Textual) (Details)	Aug. 05, 2013USD ($)a	Dec. 31, 2015USD ($)ft²property	Dec. 31, 2014USD ($)ft²property	Dec. 31, 2013USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of Properties | property		179
Impairment of properties held for use		$ 27,500,000
Aggregate carrying value		40,400,000
Estimated Fair Value Of Impaired Property		$ 12,900,000
Net rentable space of property sold | ft²		4,300,000
Net gain (loss) on sale of undepreciated real estate		$ 3,019,000	$ 1,184,000	$ (137,000)
1000 Atrium Way [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net rentable space of property sold | ft²			99,668
Libertyview [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net rentable space of property sold | 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
Dabney Land, East [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Acreage of Land | a	8
Sales price of properties sold	$ 500,000
Net gain (loss) on sale of undepreciated real estate	$ (100,000)
Metropolitan DC [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		$ 27,500,000
Aggregate carrying value		40,400,000
Estimated Fair Value Of Impaired Property		$ 12,900,000
Impairment Hold Period		10 years
Residual Capitalization Rates		8.00%
Discount Rates		8.00%

Real Estate Investments - Intan

Real Estate Investments - Intangible Assets Acquired and Intangible Liabilities Assumed (Details) - Commerce Square [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2013	Dec. 19, 2013
Acquired Finite Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ 85,036
Leases, Acquired-in-Place [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		80,916
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	7 years 10 months 24 days
Above Market Leases [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		4,120
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 10 months 24 days
Below Market Lease [Member]
Acquired Finite Lived Intangible Assets [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles		$ (8,637)
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	6 years 6 months

Investment in Unconsolidated 76

Investment in Unconsolidated Ventures (Textual) (Details) $ in Thousands		Dec. 30, 2015USD ($)	May. 29, 2015USD ($)a	Jan. 30, 2015USD ($)	Oct. 21, 2014USD ($)	Oct. 17, 2014USD ($)ft²property	Jul. 31, 2014USD ($)ft²propertyStorey	Apr. 03, 2014USD ($)ft²propertyStorey	Feb. 19, 2014USD ($)ft²Floor	Oct. 16, 2013USD ($)ft²property	Jul. 31, 2013USD ($)ft²a	Jun. 19, 2013USD ($)	Dec. 31, 2015USD ($)ft²apropertyStoreyReal_Estate_VenturesBuildingApartment_unit		Dec. 31, 2014USD ($)ft²property		Dec. 31, 2013USD ($)ft²propertyStorey	Dec. 31, 2011USD ($)	Jun. 22, 2015	Mar. 26, 2013USD ($)	Jan. 25, 2013USD ($)aStoreyBed	Jan. 20, 2011a	Dec. 19, 2007ft²property
Schedule Of Equity Method Investments [Line Items]
Number of unconsolidated investments in Real Estate Ventures | Real_Estate_Ventures													16
Equity Method Investments including net liabilities													$ 239,874		$ 223,790
Company's share of equity (Company's basis)													$ 241,004		225,004		$ 180,512
Number of negative investment real estate ventures | Real_Estate_Ventures													1
Rentable Square Feet | ft²													4,300,000
Number of real estate ventures that owns undeveloped land | Real_Estate_Ventures													2
Area owned by real estate venture of undeveloped parcels of land | a													4.3
Number of real estate ventures that owns land under development | Real_Estate_Ventures													3
Area owned by real estate venture in parcels of land under development | a													2.2
Number of real estate Investments in residential towers | Real_Estate_Ventures													1
Number of apartment units in a real estate Venture | Apartment_unit													345
Number of real estate investments in apartment complex | Real_Estate_Ventures													1
Number of apartment complex in a real estate Venture | Apartment_unit													398
Minimum percentage of unconsolidated equity method investment ownership													20.00%
Maximum percentage of unconsolidated equity method investment ownership													70.00%
Ownership percentage	[1]												0.00%
Proceeds from Equity Method Investment, Dividends or Distributions													$ 6,100		0		16,963
Carrying value of assets													$ 422,900
Number of Properties | property													179
Net gain on sale of undepreciated real estate													$ 0		8,212		0
Acquisition of properties													150,472		18,443		161,604
Proceeds from repayment of mortgage notes receivable													88,000		7,026		200
Payments to Acquire Equity Method Investments													68,549		46,098		33,069
Net gain from remeasurement of investments in real estate ventures													758		458		6,866
Net gain on real estate venture transactions													7,418		$ (417)		$ 3,683
TB-BDN Plymouth Apartments [Member]
Schedule Of Equity Method Investments [Line Items]
Guarantor obligations, current carrying value													3,200
1919 Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Guarantor obligations, current carrying value													$ 88,900
Encino Trace - Land [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²									320,000				320,000
Payments to Acquire Land									$ 14,000
Number of Properties | property													2
Number of floors of a building									4				4
Office Building [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²													2,649,926		645,273		2,472,036
Number of Properties | property													27		8		21
Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²																	192,396
Number of Properties | property								2									2
Number of floors of a building | Storey								3									3
Four Points Centre [Member] | Office Building [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²															192,396
Number of Properties | property															2
Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage																			50.00%
Coppell Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)	[2]												$ 1,130		$ 1,214
Ownership percentage	[1],[2]												50.00%
Real Estate Ventures Owned Office Buildings [Member]
Schedule Of Equity Method Investments [Line Items]
Number of real estate ventures that owns buildings | Real_Estate_Ventures													9
Number of office buildings in Real Estate Ventures | Building													31
Residence Inn Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)		$ 900											$ 0	[3]	723	[3]
Ownership percentage		50.00%											0.00%	[1],[3]
Proceeds from Equity Method Investment, Dividends or Distributions		$ 6,100
Gain on sale of its interest in the real estate venture		$ 5,200
51 N 50 Patterson [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)													$ 16,725		0
Area owned by real estate venture of undeveloped parcels of land | a			0.9
Ownership percentage			70.00%										70.00%	[1]
Payments to Acquire Land			$ 15,200
51 N 50 Patterson [Member] | JBG [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage			30.00%
Payments to Acquire Land			$ 6,500
1250 First Street Office [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)													$ 14,312		0
Area owned by real estate venture of undeveloped parcels of land | a			0.5
Ownership percentage			70.00%										70.00%	[1]
Payments to Acquire Land			$ 13,200
1250 First Street Office [Member] | JBG [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage			30.00%
Payments to Acquire Land			$ 5,700
25 M Street [Member]
Schedule Of Equity Method Investments [Line Items]
Carrying value of assets													$ 20,500
GI Interchange Office LLC (DRA — N. PA) [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)	[3]												$ 0		0
Rentable Square Feet | ft²																							1,611,961
Ownership percentage	[1],[3]												0.00%
Number of Properties | property																							29
GI Interchange Office LLC (DRA — N. PA) [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage																							20.00%
Brandywine Nineteen Nineteen Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)	[4],[5]												$ 29,086		12,823
Area owned by real estate venture of undeveloped parcels of land | a																						1
Ownership percentage													50.00%	[1],[4],[5]								50.00%
Payments to Acquire Land																		$ 9,300
Brandywine Nineteen Nineteen Ventures [Member] | LCOR/Calstrs [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage					50.00%
Aggregate gross sales price of a joint venture					$ 16,400
General Partners' Contributed Capital					5,200
Net gain on sale of undepreciated real estate					$ 8,200
Outstanding construction loan													$ 19,400
Equity method investments, Cash contributions													29,600
Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)	[4]												$ 60,427		40,374
Rentable Square Feet | ft²						590,881	232,274
Ownership percentage	[1],[4]												50.00%
Number of Properties | property						7	2
Equity method investments, Cash contributions						$ 18,900	$ 12,800
Equity method investments, Closing costs						200	100
Equity method investment, Consideration transferred							48,200
Mortgage loans outstanding							$ 34,500
Mortgage loans interest rate							3.87%
Equity Method Investments Purchase Adjustments							$ 900
Business acquisition cost of acquired entity transaction costs borne by seller							600
Acquisition of properties						128,100
Short-term Bank Loans and Notes Payable						$ 88,000
Austin Joint Venture [Member] | Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Non-Recourse Debt								$ 29,000
Austin Joint Venture [Member] | Four Points Centre [Member] | Office Building [Member]
Schedule Of Equity Method Investments [Line Items]
Rentable Square Feet | ft²								192,396
Austin Joint Venture [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage													50.00%
Aggregate gross sales price of a joint venture										$ 330,000
Equity method investments, Cash contributions							$ 6,400
Number of properties contributed to a joint venture | property										7
Area of Real Estate Property | ft²										1,398,826
Equity method investment, agreement to pay future capital expenditures										$ 5,200							$ 800
Equity Method Investment, Additional Distribution Rights													10.00%
Net gain (loss) on real estate venture transactions																	25,900
Austin Joint Venture [Member] | Brandywine Realty Trust [Member] | Four Points Centre [Member]
Schedule Of Equity Method Investments [Line Items]
Aggregate gross sales price of a joint venture								$ 41,500
Amount Of Participant Contribution								5,900
Proceeds from Equity Method Investment, Dividends or Distributions								$ 34,400
Austin Joint Venture [Member] | DRA Advisors LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage													50.00%
Equity Method Investment, Distribution, Net of Initial Funding Agreement										266,300
Amount Of Participant Contribution										49,700
Equity method investments, Closing costs										1,900
Closing Prorations and Lender Holdbacks										6,900
Proceeds from Equity Method Investment, Dividends or Distributions										271,500
Non-Recourse Debt										$ 230,600
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
River Place [Member]
Schedule Of Equity Method Investments [Line Items]
Proceeds from repayment of mortgage notes receivable				$ 88,000
4040 Wilson Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)													$ 36,626		27,415
Area owned by real estate venture of undeveloped parcels of land | a											1.3
Ownership percentage	[1]												50.00%
Area of Real Estate Property | ft²											426,900
Equity Method Investment, Budgeted Total Project Cost											$ 194,600
Payments to Acquire Equity Method Investments											72,000
4040 Wilson Venture [Member] | Brandywine Realty Trust [Member]
Schedule Of Equity Method Investments [Line Items]
Payments to Acquire Interest in Joint Venture											36,000		$ 35,600
4040 Wilson Venture [Member] | Ashton Park [Member]
Schedule Of Equity Method Investments [Line Items]
Fair value of land, net of amount encumbered											$ 36,000
Six Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Net gain from remeasurement of investments in real estate ventures																	7,800
Fair Value of Contingent Consideration												$ 24,500
Business Acquisition Purchase Price Allocation Building												14,800
Business Acquisition Purchase Price Allocation Land Portion												6,900
Business Acquisition Purchase Price Allocation Intangible Assets												3,300
Business Acquisition Purchase Price Allocated To Market Lease Liabilities												500
Two Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)												(100)
Investments, Fair Value Disclosure												$ 3,600
Net gain on real estate venture transactions																	$ 3,700
The Grove at Cira Centre South [Member]
Schedule Of Equity Method Investments [Line Items]
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
Guarantor obligations, current carrying value													24,700
Equity Method Investment, Aggregate Cost																					4,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity																					$ 4,500
The Grove at Cira Centre South [Member] | Campus Crest Properties, LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage																					30.00%
The Grove at Cira Centre South [Member] | HSRE, LLC [Member] [Member]
Schedule Of Equity Method Investments [Line Items]
Ownership percentage																					40.00%
BDN Beacon Venture LLC [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)																				$ 17,000
Ownership percentage																				20.00%
PJP VII [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)													$ 872		$ 911
Ownership percentage	[1]												25.00%
Guarantor obligations, current carrying value													$ 500
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	Carrying amount represents the negative investment balance of the venture and is included in other liabilities.
[3]	The ownership interest in Invesco, L.P. was sold prior to December 31, 2014. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in DRA-N. PA was disposed of on August 12, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2015 dispositions.
[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).
[5]	The stated rate for the construction loan is LIBOR + 2.25%. The interest rate spread decreases to 2.00% upon receipt of certificate of occupancy. It is further reduced to 1.75% upon stabilization. To fulfill interest rate protection requirements an interest rate cap was purchased at 4.50%.

Investment in Unconsolidated 77

Investment in Unconsolidated Ventures - Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013	Dec. 30, 2015	May. 29, 2015	Jan. 20, 2011
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	0.00%
Investment in Real Estate Ventures, at equity		$ 241,004		$ 225,004		$ 180,512
Equity Method Investments including net liabilities		239,874		223,790
Company’s share of income (loss) (Company’s basis)		(811)		(790)		$ 3,664
Equity Method Investment Summarized Financial Information Debt		$ 794,571		965,077
Debt Instrument, Interest Rate, Effective Percentage		0.00%
Brandywine - Al Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	50.00%
Investment in Real Estate Ventures, at equity		$ 50,760		45,712
Company’s share of income (loss) (Company’s basis)		(229)		(185)
Equity Method Investment Summarized Financial Information Debt		$ 132,717		133,843
Debt Instrument, Interest Rate, Effective Percentage		3.94%
Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[2]	50.00%
Investment in Real Estate Ventures, at equity	[2]	$ 60,427		40,374
Company’s share of income (loss) (Company’s basis)	[2]	(1,235)		(574)
Equity Method Investment Summarized Financial Information Debt	[2]	$ 410,066		382,100
Debt Instrument, Interest Rate, Effective Percentage	[2]	3.38%
One Thousand Chesterbrook Blvd. [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	50.00%
Investment in Real Estate Ventures, at equity		$ 1,895		2,152
Company’s share of income (loss) (Company’s basis)		117		388
Equity Method Investment Summarized Financial Information Debt		$ 23,610		24,251
Debt Instrument, Interest Rate, Effective Percentage		4.75%
Four Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	65.00%
Investment in Real Estate Ventures, at equity		$ 1,684		1,474
Company’s share of income (loss) (Company’s basis)		211		(144)
Equity Method Investment Summarized Financial Information Debt		$ 10,162		10,353
Debt Instrument, Interest Rate, Effective Percentage		5.20%
PJP VII [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	25.00%
Investment in Real Estate Ventures, at equity		$ 872		911
Company’s share of income (loss) (Company’s basis)		211		177
Equity Method Investment Summarized Financial Information Debt		$ 5,621		5,785
Debt Instrument, Interest Rate Terms		0
PJP Two [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	30.00%
Investment in Real Estate Ventures, at equity		$ 435		403
Company’s share of income (loss) (Company’s basis)		32		73
Equity Method Investment Summarized Financial Information Debt		$ 3,201		3,492
Debt Instrument, Interest Rate, Effective Percentage		6.12%
PJP Five [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	25.00%
Investment in Real Estate Ventures, at equity		$ 305		216
Company’s share of income (loss) (Company’s basis)		189		166
Equity Method Investment Summarized Financial Information Debt		$ 5,035		5,242
Debt Instrument, Interest Rate, Effective Percentage		6.47%
PJP Six [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	25.00%
Investment in Real Estate Ventures, at equity		$ 45		45
Company’s share of income (loss) (Company’s basis)		151		(67)
Equity Method Investment Summarized Financial Information Debt		$ 7,918		8,168
Debt Instrument, Interest Rate, Effective Percentage		6.08%
Invesco, L.P. [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[3]	0.00%
Investment in Real Estate Ventures, at equity	[3]	$ 0		0
Company’s share of income (loss) (Company’s basis)	[3]	349		989
Equity Method Investment Summarized Financial Information Debt	[3]	$ 0		0
Debt Instrument, Interest Rate, Effective Percentage	[3]	0.00%
Debt Instrument, Interest Rate Terms	[3]	0
Broadmoor Austin Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[3]	0.00%
Investment in Real Estate Ventures, at equity	[3]	$ 0		65,407
Company’s share of income (loss) (Company’s basis)	[3]	(377)		(460)
Equity Method Investment Summarized Financial Information Debt	[3]	$ 0		53,516
Debt Instrument, Interest Rate, Effective Percentage	[3]	0.00%
Debt Instrument, Interest Rate Terms	[3]	0
GI Interchange Office LLC (DRA — N. PA) [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[3]	0.00%
Investment in Real Estate Ventures, at equity	[3]	$ 0		0
Company’s share of income (loss) (Company’s basis)	[3]	0		(658)
Equity Method Investment Summarized Financial Information Debt	[3]	$ 0		174,595
Debt Instrument, Interest Rate, Effective Percentage	[3]	0.00%
Coppell Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[4]	50.00%
Investment in Real Estate Ventures, at equity	[4]	$ (1,130)		(1,214)
Company’s share of income (loss) (Company’s basis)	[4]	84		(45)
Equity Method Investment Summarized Financial Information Debt	[4]	$ 15,515		15,747
Debt Instrument, Interest Rate, Effective Percentage	[4]	5.75%
HSRE, LLC [Member] [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1],[2]	30.00%
Investment in Real Estate Ventures, at equity	[2]	$ 15,003		14,314
Company’s share of income (loss) (Company’s basis)	[2]	(188)		67
Equity Method Investment Summarized Financial Information Debt	[2]	$ 95,562		90,245
Debt Instrument, Interest Rate Terms	[2]	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, at equity		$ 36,626		27,415
Company’s share of income (loss) (Company’s basis)		(106)		(132)
Equity Method Investment Summarized Financial Information Debt		$ 0		0
Debt Instrument, Interest Rate, Effective Percentage		0.00%
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, at equity		$ 12,338		12,720
Company’s share of income (loss) (Company’s basis)		(252)		(83)
Equity Method Investment Summarized Financial Information Debt		$ 50,964		29,481
Debt Instrument, Interest Rate Terms		0
Residence Inn Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		0.00%	[1],[3]				50.00%
Investment in Real Estate Ventures, at equity		$ 0	[3]	723	[3]		$ 900
Company’s share of income (loss) (Company’s basis)	[3]	367		107
Equity Method Investment Summarized Financial Information Debt	[3]	$ 0		13,394
Debt Instrument, Interest Rate, Effective Percentage	[3]	0.00%
Debt Instrument, Interest Rate Terms	[3]	0
Brandywine Nineteen Nineteen Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage		50.00%	[1],[2],[5]						50.00%
Investment in Real Estate Ventures, at equity	[2],[5]	$ 29,086		12,823
Company’s share of income (loss) (Company’s basis)	[2],[5]	0		(21)
Equity Method Investment Summarized Financial Information Debt	[2],[5]	$ 19,411		0
Debt Instrument, Interest Rate Terms	[2],[5]	0
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, at equity		$ 16,725		0
Company’s share of income (loss) (Company’s basis)		0		0
Equity Method Investment Summarized Financial Information Debt		$ 0		0
Debt Instrument, Interest Rate, Effective Percentage		0.00%
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, at equity		$ 14,312		0
Company’s share of income (loss) (Company’s basis)		0		0
Equity Method Investment Summarized Financial Information Debt		$ 0		0
Debt Instrument, Interest Rate, Effective Percentage		0.00%
Seven Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Equity Method Investment, Ownership Percentage	[1]	20.00%
Investment in Real Estate Ventures, at equity		$ 491		315
Company’s share of income (loss) (Company’s basis)		(135)		(388)
Equity Method Investment Summarized Financial Information Debt		$ 14,789		$ 14,865
Debt Instrument, Interest Rate, Effective Percentage		3.44%
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.
[2]	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).
[3]	The ownership interest in Invesco, L.P. was sold prior to December 31, 2014. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in DRA-N. PA was disposed of on August 12, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2015 dispositions.
[4]	Carrying amount represents the negative investment balance of the venture and is included in other liabilities.
[5]	The stated rate for the construction loan is LIBOR + 2.25%. The interest rate spread decreases to 2.00% upon receipt of certificate of occupancy. It is further reduced to 1.75% upon stabilization. To fulfill interest rate protection requirements an interest rate cap was purchased at 4.50%.

Investment in Unconsolidated 78

Investment in Unconsolidated Ventures - Investment in Real Estate Ventures and Share of Real Estate Ventures' Income (Loss) (Parenthetical) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Jun. 22, 2015	Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		0.00%
Equity Method Investment Summarized Financial Information Debt		$ 794,571		$ 965,077
Brandywine - Al Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		3.94%
Equity Method Investment Summarized Financial Information Debt		$ 132,717		133,843
Austin Joint Venture [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.38%
Equity Method Investment Summarized Financial Information Debt	[1]	$ 410,066		382,100
Brandywine Nineteen Nineteen Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate Terms		LIBOR + 2.25
Interest rate protection cap		4.50%
Interest rate upon receipt of certificate of occupancy		2.00%
Interest rate upon stabilization		1.75%
Equity Method Investment Summarized Financial Information Debt	[1],[2]	$ 19,411		0
Seven Tower Bridge [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Effective Percentage		3.44%
Equity Method Investment Summarized Financial Information Debt		$ 14,789		14,865
Broadmoor Austin Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Effective Percentage	[3]	0.00%
Equity Method Investment Summarized Financial Information Debt	[3]	$ 0		$ 53,516
Percentage of ownership interests			50.00%
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		$ 38,800
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		$ 27,600
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		3.94%
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		$ 34,000
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		$ 55,800
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		$ 140,300
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		$ 34,500
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		$ 86,400
Debt Instrument Maturity Date		Feb. 28, 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
Long-term Debt, Weighted Average Interest Rate		3.38%
Debt Instrument, Interest Rate Terms		LIBOR + 1.85
Interest rate protection cap		2.75%
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		$ 900
Secured JV Debt [Member] | Seven Tower Bridge [Member] | Fixed Rate Loan Maturing February 2016 [Member]
Schedule Of Equity Method Investments [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.00%
Debt Instrument Maturity Date		Feb. 7, 2016
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		3.00%
Debt Instrument Maturity Date		Mar. 11, 2020
Long-term Debt, Weighted Average Interest Rate		3.40%
Equity Method Investment Summarized Financial Information Debt		$ 3,900
[1]	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).
[2]	The stated rate for the construction loan is LIBOR + 2.25%. The interest rate spread decreases to 2.00% upon receipt of certificate of occupancy. It is further reduced to 1.75% upon stabilization. To fulfill interest rate protection requirements an interest rate cap was purchased at 4.50%.
[3]	The ownership interest in Invesco, L.P. was sold prior to December 31, 2014. The Company purchased the remaining 50% interest in Broadmoor Austin Associates on June 22, 2015. The ownership interest in DRA-N. PA was disposed of on August 12, 2015. The ownership interest in Residence Inn Tower Bridge was sold on December 30, 2015. See below for further detail on 2015 dispositions.

Investment in Unconsolidated 79

Investment in Unconsolidated Ventures - Summary of Financial Position of Real Estate Ventures (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Equity Method Investments [Line Items]
Debt		$ 794,571	$ 965,077
Company's share of equity (Company's basis)		241,004	225,004	$ 180,512
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Net property		1,258,999	1,281,282
Other assets		158,672	195,121
Other liabilities		68,028	68,481
Debt		794,571	965,077
Equity		554,072	442,845
Company's share of equity (Company's basis)	[1],[2]	$ 241,004	$ 225,004
[1]	Does not include the negative investment balance of one real estate venture totaling $1.1 million and $1.2 million as of December 31, 2015 and 2014, respectively, which is included in other liabilities.
[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 Ventures - Summary of Financial Position of Real Estate Ventures (Parenthetical) (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Coppell Associates [Member]
Schedule Of Equity Method Investments [Line Items]
Company's share of equity (Company's basis)	[1]	$ 1,130	$ 1,214
[1]	Carrying amount represents the negative investment balance of the venture and is included in other liabilities.

Investment in Unconsolidated 81

Investment in Unconsolidated Ventures - Summary of Results of Operations of Real Estate Ventures with Interests (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule Of Equity Method Investments [Line Items]
Company’s share of income (loss) (Company’s basis)	$ (811)	$ (790)	$ 3,664
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
Revenue	164,928	147,236	102,919
Operating expenses	(70,136)	(61,268)	(40,436)
Interest expense, net	(34,584)	(36,511)	(26,529)
Depreciation and amortization	(68,100)	(57,109)	(35,138)
Net income (loss)	(7,892)	(7,652)	816
Company’s share of income (loss) (Company’s basis)	$ (811)	$ (790)	$ 3,664

Investment in Unconsolidated 82

Investment in Unconsolidated Ventures - Aggregate Principal Payments of Recourse and Non-recourse Debt Payable to Third-parties (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]
2,016	$ 249,468
2,017	333,682
2,018	340,437
2,019	16,768
2,020	17,661
Thereafter	1,458,208
Equity Method Investment Summarized Financial Information Debt	794,571	$ 965,077
Unconsolidated Real Estate Ventures [Member]
Schedule Of Equity Method Investments [Line Items]
2,016	120,811
2,017	68,319
2,018	244,403
2,019	175,975
2,020	92,761
Thereafter	92,302
Equity Method Investment Summarized Financial Information Debt	$ 794,571	$ 965,077

Deferred Costs - Deferred Costs

Deferred Costs - Deferred Costs (Assets) (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Components of Deferred Costs Net [Abstract]
Leasing costs, Total Cost		$ 165,741	$ 164,081
Total Cost		169,319	168,669
Leasing costs, Accumulated Amortization		(67,342)	(64,065)
Total, Accumulated Amortization		(67,900)	(67,408)
Leasing costs, Deferred Costs, net		98,399	100,016
Deferred Costs		101,419	101,261
Financing costs, Deferred Costs, net		22,595
Revolving Credit Facility
Components of Deferred Costs Net [Abstract]
Financing costs, Total Cost	[1]	3,578	4,588
Financing costs, Accumulated Amortization	[1]	(558)	3,343
Financing costs, Deferred Costs, net	[1]	$ 3,020	$ 1,245
[1]	During the fourth quarter of 2015, the Company adopted accounting guidance related to the presentation of deferred financing costs on the balance sheet and reclassified amounts from the deferred costs line to net against the debt liability for all periods presented. Only deferred financing costs associated with our credit facility remain in deferred costs (assets) on the consolidated balance sheets. See Note 2, “Summary of Significant Accounting Policies,” for revisions to the accounting guidance for deferred financing costs.

Deferred Costs (Textual) (Detai

Deferred Costs (Textual) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Costs (Textuals) [Abstract]
Capitalized internal direct leasing costs	$ 6.6	$ 7.1	$ 7.5

Intangible Assets - Intangible

Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Intangible Assets [Line Items]
Intangible Assets, Total Cost	$ 183,872	$ 169,224
Intangible Assets, Accumulated Amortization	(72,249)	(69,821)
Intangible Assets, net	111,623	99,403
Acquired Lease Intangibles, Gross	48,956	53,049
Acquired Lease Intangibles, Accumulated Amortization	(23,301)	(27,039)
Acquired Lease Intangibles, Net	25,655	26,010
Below market leases [Member]
Intangible Assets [Line Items]
Acquired Lease Intangibles, Gross	50,025
Acquired Lease Intangibles, Accumulated Amortization	(24,178)
Acquired Lease Intangibles, Net	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	161,276	129,411
Intangible Assets, Accumulated Amortization	(57,063)	(42,068)
Intangible Assets, net	104,213	87,343
Tenant relationship value [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	20,117	34,172
Intangible Assets, Accumulated Amortization	(15,580)	(26,344)
Intangible Assets, net	4,537	7,828
Above market leases acquired [Member]
Intangible Assets [Line Items]
Intangible Assets, Total Cost	5,333	5,641
Intangible Assets, Accumulated Amortization	(1,879)	(1,409)
Intangible Assets, net	3,454	$ 4,232
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) - Tenant Move-Outs Prior to End of the Lease Term [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Finite Lived Intangible Assets [Line Items]
Intangible Assets Written Off Through Accelerated Amortization	$ 0.5	$ 0.8	$ 1.6
Intangible Liabilities Written Off Through Accelerated Amortization

Intangible Assets - Annual Amor

Intangible Assets - Annual Amortization of Intangible Assets, Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets
Total	$ 111,623	$ 99,403
Liabilities
Total	25,655	$ 26,010
Assets [Member]
Assets
2,016	36,635
2,017	19,814
2,018	12,587
2,019	11,288
2,020	9,149
Thereafter	22,731
Finite Lived Intangible Assets Net Including Assets Held For Sale	112,204
Assets held for sale	(581)
Total	111,623
Liabilities [Member]
Liabilities
2,016	7,595
2,017	3,461
2,018	2,217
2,019	1,885
2,020	1,337
Thereafter	9,352
Below Market Lease Including Assets Held for Sale	25,847
Assets held for sale	(192)
Total	$ 25,655

Debt Obligations - Consolidated

Debt Obligations - Consolidated Debt Obligations Outstanding (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2015	Oct. 07, 2015	Dec. 31, 2015	Oct. 08, 2015	Dec. 31, 2014
Consolidated debt obligations
Plus: premiums/(discounts), net	$ (8,912)	$ (8,912)		$ (8,912)
Less: deferred financing costs	(22,595)	(22,595)		(22,595)
Total Debt Obligations	$ 2,384,717	$ 2,384,717		$ 2,384,717		$ 2,427,345
Effective interest rate	0.00%	0.00%		0.00%
Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 562,695	$ 562,695		$ 562,695		655,934
Plus: premiums/(discounts), net	(3,198)	(3,198)		(3,198)		(1,344)
Less: deferred financing costs	(13,744)	(13,744)		(13,744)		(14,959)
Total mortgage indebtedness	545,753	545,753		545,753		639,631
Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	1,853,529	1,853,529		1,853,529		1,803,529
Plus: premiums/(discounts), net	(5,714)	(5,714)		(5,714)		(6,811)
Less: deferred financing costs	(8,851)	(8,851)		(8,851)		(9,004)
Total unsecured indebtedness	1,838,964	1,838,964		1,838,964		1,787,714
Tysons Corner [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 0	$ 0		$ 0		89,513
Effective interest rate	5.36%	5.36%		5.36%
Debt Instrument Maturity Date				Oct. 9, 2015
Two Logan Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 86,886	$ 86,886		$ 86,886		87,767
Effective interest rate	7.57%	7.57%		7.57%
Debt Instrument Maturity Date				Apr. 1, 2016
Fairview Eleven Tower [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 20,838	$ 20,838		$ 20,838		21,242
Effective interest rate	4.25%	4.25%		4.25%
Debt Instrument Maturity Date				Jan. 1, 2017
One Commerce Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 130,000	$ 130,000		$ 130,000		123,205
Effective interest rate	3.64%	3.64%		3.64%
Debt Instrument Maturity Date	Apr. 5, 2023			Jan. 6, 2016
Two Commerce Square [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 112,000	$ 112,000		$ 112,000		112,000
Effective interest rate	4.51%	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	$ 177,425	$ 177,425		$ 177,425		184,442
Effective interest rate	7.00%	7.00%		7.00%
Debt Instrument Maturity Date				Sep. 10, 2030
Cira South Garage [Member] | Secured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 35,546	$ 35,546		$ 35,546		37,765
Effective interest rate	7.12%	7.12%		7.12%
Debt Instrument Maturity Date				Sep. 10, 2030
Seven Year Term Loan - Swapped to fixed [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 250,000	$ 250,000	$ 200,000	$ 250,000	$ 250,000	200,000
Effective interest rate	3.72%	3.72%		3.72%	3.72%
Debt Instrument Maturity Date		Oct. 8, 2022	Feb. 1, 2019
$250.0M 6.00% Guaranteed Notes due 2016 [Member] | Unsecured Debt [Member]
Consolidated debt obligations
Long-term Debt, Gross	$ 149,919	$ 149,919		$ 149,919		149,919
Effective interest rate	5.95%	5.95%		5.95%
Debt Instrument Maturity Date				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		300,000
Effective interest rate	5.68%	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		325,000
Effective interest rate	5.13%	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		250,000
Effective interest rate	4.02%	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		250,000
Effective interest rate	4.33%	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		250,000
Effective interest rate	4.60%	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		27,062
Effective interest rate	2.75%	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		25,774
Effective interest rate	3.30%	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		$ 25,774
Effective interest rate	3.09%	3.09%		3.09%
Debt Instrument Maturity Date				Jul. 30, 2035

Debt Obligations - Consolidat89

Debt Obligations - Consolidated Debt Obligations Outstanding (Parenthetical) (Details)		Dec. 31, 2015USD ($)property	Dec. 29, 2015USD ($)	Oct. 09, 2015USD ($)	Oct. 08, 2015USD ($)	Dec. 31, 2015USD ($)property	Oct. 07, 2015USD ($)	Dec. 31, 2015USD ($)property	Aug. 19, 2015property	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Number of Properties | property		179				179		179
Equity Method Investment, Ownership Percentage	[1]	0.00%				0.00%		0.00%
Effective interest rate		0.00%				0.00%		0.00%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Unsecured term loans		$ 1,853,529,000				$ 1,853,529,000		$ 1,853,529,000		$ 1,803,529,000
Secured Debt [Member]
Debt Instrument [Line Items]
Unsecured term loans		$ 562,695,000				$ 562,695,000		$ 562,695,000		655,934,000
Seven Year Term Loan - Swapped to fixed [Member] | Unsecured Debt [Member]
Debt Instrument [Line Items]
Debt term					7 years
Debt Instrument Maturity Date						Oct. 8, 2022	Feb. 1, 2019
Effective interest rate		3.72%			3.72%	3.72%		3.72%
Unsecured term loans		$ 250,000,000			$ 250,000,000	$ 250,000,000	$ 200,000,000	$ 250,000,000		200,000,000
Increase in debt					50,000,000
Increase in limit					$ 150,000,000
Seven Year Term Loan - Swapped to fixed [Member] | Unsecured Debt [Member] | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate					1.80%
Tysons Corner [Member] | Mortgages [Member]
Debt Instrument [Line Items]
Number of Properties | property									2
Repayments of debt				$ 88,400,000
Accrued interest				$ 400,000
Tysons Corner [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date								Oct. 9, 2015
Effective interest rate		5.36%				5.36%		5.36%
Unsecured term loans		$ 0				$ 0		$ 0		89,513,000
Fairview Eleven Tower [Member]
Debt Instrument [Line Items]
Equity Method Investment, Ownership Percentage		50.00%				50.00%		50.00%
Fairview Eleven Tower [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt Instrument Maturity Date								Jan. 1, 2017
Effective interest rate		4.25%				4.25%		4.25%
Unsecured term loans		$ 20,838,000				$ 20,838,000		$ 20,838,000		21,242,000
One Commerce Square [Member] | Secured Debt [Member]
Debt Instrument [Line Items]
Debt instrument increase in principal			$ 130,000,000
Debt Instrument Maturity Date		Apr. 5, 2023						Jan. 6, 2016
Effective interest rate		3.64%				3.64%		3.64%
Unsecured term loans		$ 130,000,000				$ 130,000,000		$ 130,000,000		$ 123,205,000
[1]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.

Debt Obligations (Textual) (Det

Debt Obligations (Textual) (Details) - USD ($)	May. 12, 2015	Sep. 16, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	May. 15, 2015
Debt Instrument [Line Items]
Extinguishment of Debt, Amount			$ 0	$ 376,174,000	$ 29,250,000
Loss on early extinguishment of debt			0	(7,594,000)	(2,119,000)
Write off of Deferred Debt Issuance Cost				152,000	40,000
Recognized hedge activity			$ 0	$ (828,000)	$ 0
Financial and operating covenant description			The restriction on dividends permits the Company to pay dividends to the greater of (i) an amount required for the Company to retain its qualification as a REIT and (ii) 95% of its funds from operations. The term loan includes financial covenants that require the Company to maintain an interest coverage ratio, a fixed charge coverage ratio and an unencumbered cash flow ratio above specified levels; to maintain a minimum net worth above an amount determined on a specified formula; and to maintain a leverage ratio and a secured debt ratio below certain maximum levels.
Percentage of fund from operations			95.00%
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] | Revolving Credit Facility | LIBOR [Member]
Debt Instrument [Line Items]
Basis spread on variable rate			1.20%
Basis spread on variable rate			1.00%
New Credit Facility [Member] | Revolving Credit Facility | LIBOR [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate			0.875%
New Credit Facility [Member] | Revolving Credit Facility | LIBOR [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate			1.55%
New Credit Facility [Member] | Revolving Credit Facility | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate			0.50%
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
Secured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Weighted Average Interest Rate			5.72%	5.72%	5.73%
Long-term Debt, Gross			$ 562,695,000	$ 655,934,000
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			1,853,529,000	1,803,529,000
Recognized hedge activity		$ 800,000
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
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			$ 1,300,000	1,500,000
Debt Instrument Maturity Date			Oct. 1, 2024
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
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			$ 1,800,000	2,000,000
Debt Instrument Maturity Date			Oct. 1, 2029
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%
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%
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]
Write off of Deferred Debt Issuance Cost		$ 300,000
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 ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Extinguishment Of Debt [Line Items]
Principal	$ 0	$ 376,174,000	$ 29,250,000
Repurchase Amount	0	383,768,000	31,369,000
Gain (Loss) on Early Extinguishment of Debt	$ 0	(7,594,000)	(2,119,000)
Acceleration of Deferred Financing		152,000	40,000
$250.0M 5.400% Guaranteed Notes due 2014 [Member]
Extinguishment Of Debt [Line Items]
Principal		218,549,000	19,830,000
Repurchase Amount		219,404,000	20,853,000
Gain (Loss) on Early Extinguishment of Debt		(855,000)	(1,020,000)
Acceleration of Deferred Financing		9,000	16,000
7.50% Guaranteed Notes due May 15, 2015 [Member]
Extinguishment Of Debt [Line Items]
Principal		157,625,000	8,910,000
Repurchase Amount		164,364,000	9,945,000
Gain (Loss) on Early Extinguishment of Debt		(6,739,000)	(1,036,000)
Acceleration of Deferred Financing		$ 143,000	23,000
$250.0M 6.00% Guaranteed Notes due 2016 [Member]
Extinguishment Of Debt [Line Items]
Principal			510,000
Repurchase Amount			571,000
Gain (Loss) on Early Extinguishment of Debt			(63,000)
Acceleration of Deferred Financing			$ 1,000

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, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
2,016	$ 249,468
2,017	333,682
2,018	340,437
2,019	16,768
2,020	17,661
Thereafter	1,458,208
Total principal payments	2,416,224
Net unamortized premiums/(discounts)	(8,912)
Net deferred financing costs	(22,595)
Total Debt Obligations	$ 2,384,717	$ 2,427,345

Fair Value of Financial Instr93

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Carrying Amount [Member] | Mortgages Receivable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage note receivable	[1]	$ 0	$ 88,000
Carrying Amount [Member] | Unsecured Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable		1,512,554	1,510,181
Carrying Amount [Member] | Variable Rate Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate debt		326,410	277,533
Carrying Amount [Member] | Mortgages Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	[2]	545,753	639,631
Fair Value [Member] | Mortgages Receivable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Mortgage note receivable	[1]	0	87,692
Fair Value [Member] | Unsecured Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable		1,529,346	1,593,212
Fair Value [Member] | Variable Rate Debt [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Variable rate debt		305,522	257,188
Fair Value [Member] | Mortgages Payable [Member]
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Notes payable	[2]	$ 597,377	$ 707,241
[1]	See Note 2, “Summary of Significant Accounting Policies - Notes Receivable,” for further discussion.
[2]	The IRS Philadelphia Campus mortgage debt and Cira South Garage mortgage debt were prepaid prior to their scheduled maturity. See Note 21, “Subsequent Events,” for additional information regarding the prepayment. As of December 31, 2015 the fair value of the IRS Philadelphia Campus mortgage debt and Cira South Garage mortgage debt were $177.4 million and $35.5 million, respectively.

Fair Value of Financial Instr94

Fair Value of Financial Instruments - Financial Instruments for which Estimates of Fair Value Differ from Carrying Amounts (Parenthetical) (Details) - Mortgages Payable [Member] - Fair Value [Member] - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Notes payable	[1]	$ 597,377	$ 707,241
IRS Philadelphia Campus [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Notes payable		177,400
Cira South Garage [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Notes payable		$ 35,500
[1]	The IRS Philadelphia Campus mortgage debt and Cira South Garage mortgage debt were prepaid prior to their scheduled maturity. See Note 21, “Subsequent Events,” for additional information regarding the prepayment. As of December 31, 2015 the fair value of the IRS Philadelphia Campus mortgage debt and Cira South Garage mortgage debt were $177.4 million and $35.5 million, respectively.

Fair Value of Financial Instr95

Fair Value of Financial Instruments (Textual) (Details)	12 Months Ended
	Dec. 31, 2015
Variable rate and mortgage debt [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Discount Rates	4.55%

Risk Management and Use of Fi96

Risk Management and Use of Financial Instruments - Terms and Fair Values of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Other Liabilities [Member]
Derivatives Fair Value [Line Items]
Notional Amount	$ 328,610	$ 278,610
Other Liabilities [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 3.623% Interest Rate Swap Maturing February 1, 2019 [Member]
Derivatives Fair Value [Line Items]
Derivative Liability, Notional Amount	$ 0	200,000
Derivative, Fixed Interest Rate	3.623%
Derivative Liability, Fair Value, Gross Liability Including Not Subject to Master Netting Arrangement	$ 0	(2,649)
Other Liabilities [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 3.300% Interest Rate Swap Maturing January 30, 2021 [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	$ (531)	(334)
Other Liabilities [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 3.090% Interest Rate Swap Maturing October 30, 2019 [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	$ (388)	(254)
Other Liabilities [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 2.750% Interest Rate Swap Maturing September 30, 2017 [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	$ (201)	(253)
Other Assets [Member] | Interest Rate Swap [Member] | Cash Flow Hedging [Member] | 3.718% Interest Rate Swap Maturing October 8, 2022 [Member]
Derivatives Fair Value [Line Items]
Derivative, Fixed Interest Rate	3.718%
Derivative Asset, Notional Amount	$ 250,000	0
Derivative Asset, Fair Value, Gross Asset Including Not Subject to Master Netting Arrangement	$ 1,884	$ 0

Risk Management and Use of Fi97

Risk Management and Use of Financial Instruments - Terms and Fair Values of Derivative Financial Instruments (Parentheticals) (Details) - Unsecured Debt [Member] - USD ($) $ in Thousands	Oct. 08, 2015	Dec. 31, 2015	Oct. 07, 2015	Dec. 31, 2014
Derivatives Fair Value [Line Items]
Long-term Debt, Gross		$ 1,853,529		$ 1,803,529
Seven Year Term Loan - Swapped to fixed [Member]
Derivatives Fair Value [Line Items]
Long-term Debt, Gross	$ 250,000	$ 250,000	$ 200,000	$ 200,000
Debt term	7 years
Debt Instrument Maturity Date		Oct. 8, 2022	Feb. 1, 2019
Increase in debt	$ 50,000
Interest rate swap termination fee	$ 5,300

Risk Management and Use of Fi98

Risk Management and Use of Financial Instruments (Textual) (Details) - Customer	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
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, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)ft²property
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net gain on disposition of discontinued operations	$ 0	$ 900	$ 3,382
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	$ 3,382
Net Rentable Space Sold | ft²			1.1
Number of properties sold (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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenue:
Rents									$ 486,731	$ 483,682	$ 461,387
Tenant reimbursements									85,722	84,879	79,087
Other									6,617	3,221	4,186
Total revenue	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 147,810	$ 146,558	$ 150,500	$ 152,114	602,631	596,982	562,210
Expenses:
Property operating expenses									181,170	177,330	160,406
Real estate taxes									50,623	51,844	55,612
Depreciation and amortization									219,029	208,569	197,021
Total operating expenses									568,730	473,078	446,418
Interest income									1,224	3,974	1,044
Income from discontinued operations before gain on sale of interests in real estate									0	18	825
Net gain on disposition of discontinued operations									0	900	3,382
Total discontinued operations									$ 0	918	4,207
Discontinued Operations [Member]
Revenue:
Rents										0	4,754
Tenant reimbursements										26	355
Other										0	123
Total revenue										26	5,232
Expenses:
Property operating expenses										8	1,839
Real estate taxes										0	649
Depreciation and amortization										0	1,921
Total operating expenses										8	4,409
Interest income										0	2
Income from discontinued operations before gain on sale of interests in real estate										18	825
Net gain on disposition of discontinued operations										900	3,382
Total discontinued operations										$ 918	$ 4,207

Limited Partners' Non-Contro101

Limited Partners' Non-Controlling Interests in the Parent Company (Textual) (Details) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Abstract]
Aggregate amount related to non-controlling interests classified within equity	$ 16.1	$ 17.5
Settlement value of non controlling interest in operating partnership	$ 21	$ 24.5

Beneficiaries Equity of the 102

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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator
Income (Loss) from continuing operations, Basic									$ (30,740)	$ 6,024	$ 38,982
Net (income) loss from continuing operations attributable to non-controlling interests									339	43	(357)
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(329)	(349)	(363)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Income (Loss) from continuing operations available to common Shareholders, Basic									(37,630)	(1,182)	31,362
Income from discontinued operations									0	908	4,152
Net income (loss) attributable to Common Shareholders of Brandywine Realty Trust									(37,630)	(274)	35,514
Net income (loss) from continuing operations attributable to non-controlling interests, Diluted									339	43	(357)
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(329)	(349)	(363)
Income (loss) from continuing operations available to common shareholders, Diluted									(37,630)	(1,182)	31,362
Income (loss) from discontinued operations, Diluted									0	908	4,152
Net income (loss) attributable to common shareholders, Diluted									$ (37,630)	$ (274)	$ 35,514
Denominator
Basic weighted average shares outstanding (in shares)									178,162,160	166,202,649	153,140,458
Contingent securities/Share based compensation (in shares)									0	0	1,273,853
Diluted weighted average shares outstanding (in shares)									178,162,160	166,202,649	154,414,311
Earnings (loss) per Common Share:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	(0.21)	0	0.23
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)									(0.21)	(0.01)	0.20
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	$ (0.21)	$ 0	$ 0.23

Beneficiaries Equity of the 103

Beneficiaries Equity of the Parent Company (Textuals) (Details) - USD ($)	Dec. 08, 2015	Aug. 01, 2014	Apr. 10, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Jul. 22, 2015	Nov. 05, 2013
Class of Stock [Line Items]
Distributions payable				$ 28,249,000	$ 28,871,000
Preferred Stock, Dividend Rate, Percentage				6.90%	6.90%
Dividends, Preferred Stock				$ 6,900,000	$ 6,900,000	$ 6,900,000
Issuance of Common Shares of Beneficial Interest, Shares		21,850,000	12,650,000
Net proceeds from issuance of common shares\units				$ 0	$ 335,016,000	181,527,000
Shares Authorized For Equity Offering Program								16,000,000
Additional Shares Granted under Option to Purchase in Public Offering			1,650,000
Authorized Amount							$ 100,000,000
Number of Shares Authorized to be Repurchased							539,200
Repurchased and Retired, Shares				5,209,437
Share Price				$ 12.90
Repurchased and Retired, Value				$ 67,325,000
Common stock price per share				$ 0.01	$ 0.01
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Distributions payable				$ 28,249,000	$ 28,871,000
Preferred Stock, Dividend Rate, Percentage				6.90%	6.90%
Dividends, Preferred Stock				$ 6,900,000	$ 6,900,000	6,900,000
Net proceeds from issuance of common shares\units				$ 0	$ 335,016,000	$ 181,527,000
Series E Preferred Stock [Member]
Class of Stock [Line Items]
Preferred Stock, Dividend Rate, Percentage				6.90%
Preferred Stock, Liquidation Preference Per Share				$ 25
Offering Program [Member]
Class of Stock [Line Items]
Remaining Shares Available For Sales				16,000,000
Offering Program [Member] | Maximum [Member]
Class of Stock [Line Items]
Fees and Commissions Percentage				2.00%
Dividend Declared [Member]
Class of Stock [Line Items]
Dividends Payable, Amount Per Share	$ 0.15
Dividend Declared [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Dividends Payable, Amount Per Share	$ 0.15
Dividend Paid [Member]
Class of Stock [Line Items]
Distributions payable				$ 26,500,000
Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Class of Stock [Line Items]
Distributions payable				$ 26,500,000
Dividend Paid [Member] | Series E Preferred Stock [Member]
Class of Stock [Line Items]
Dividends, Preferred Stock	$ 1,700,000
Redeemable Common Limited Partnership Units
Class of Stock [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share				1,535,102	1,535,102	1,763,739

Partners Equity of the Opera104

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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Numerator
Income (Loss) from continuing operations, Basic									$ (30,740)	$ 6,024	$ 38,982
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(329)	(349)	(363)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Income (loss) from discontinued operations, Basic									0	918	4,207
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									$ (329)	$ (349)	$ (363)
Denominator
Basic weighted average shares outstanding (in shares)									178,162,160	166,202,649	153,140,458
Contingent securities/Share based compensation (in shares)									0	0	1,273,853
Diluted weighted average shares outstanding (in shares)									178,162,160	166,202,649	154,414,311
Earnings (loss) per Common Partnership Unit:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	(0.21)	0	0.23
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)									(0.21)	(0.01)	0.20
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	$ (0.21)	$ 0	$ 0.23
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Numerator
Income (Loss) from continuing operations, Basic									$ (30,740)	$ 6,024	$ 38,982
Nonforfeitable dividends allocated to unvested restricted shareholders, Basic									(329)	(349)	(363)
Preferred Share distributions									(6,900)	(6,900)	(6,900)
Net loss attributable to non-controlling interests, Basic									3	44	0
Income (loss) from continuing operations available to common unitholders, Basic									(37,966)	(1,181)	31,719
Income (loss) from discontinued operations, Basic									0	918	4,207
Net income (loss) attributable to common unitholders, Basic									(37,966)	(263)	35,926
Nonforfeitable dividends allocated to unvested restricted shareholders, Diluted									(329)	(349)	(363)
Net loss attributable to non-controlling interests, Diluted									3	44	0
Income (loss) from continuing operations available to common unitholders, Diluted									(37,966)	(1,181)	31,719
Income (loss) from discontinued operations, diluted									0	918	4,207
Net income attributable to common unitholders, Diluted									$ (37,966)	$ (263)	$ 35,926
Denominator
Basic weighted average shares outstanding (in shares)									179,697,262	167,942,246	154,929,545
Contingent securities/Share based compensation (in shares)									0	0	1,273,853
Diluted weighted average shares outstanding (in shares)									179,697,262	167,942,246	156,203,398
Earnings (loss) per Common Partnership Unit:
Income (loss) from continuing operations attributable to common shareholders, Basic (USD per share)									$ (0.21)	$ (0.01)	$ 0.20
Discontinued operations attributable to common shareholders, Basic (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Basic (USD per share)									(0.21)	0	0.23
Income (loss) from continuing operations attributable to common shareholders, Dilued (USD per share)									(0.21)	(0.01)	0.20
Discontinued operations attributable to common shareholders, Diluted (USD per share)									0	0.01	0.03
Net income (loss) attributable to common shareholders, Diluted (USD per share)									$ (0.21)	$ 0	$ 0.23

Partners Equity of the Opera105

Partners Equity of the Operating Partnership (Textual) (Details) - USD ($)	Dec. 08, 2015	Dec. 31, 2015	Dec. 31, 2014	Jul. 22, 2015	Dec. 31, 2013	Nov. 05, 2013
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 28,249,000	$ 28,871,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Shares Authorized For Equity Offering Program						16,000,000
Authorized Amount				$ 100,000,000
Number of Shares Authorized to be Repurchased				539,200
Repurchased and Retired, Shares		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		$ 28,249,000	$ 28,871,000
Preferred Stock, Dividend Rate, Percentage		6.90%	6.90%
Dividend Declared [Member]
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.15
Dividend Declared [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Dividends Payable, Amount Per Share	$ 0.15
Dividend Paid [Member]
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 26,500,000
Dividend Paid [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Earnings Per Common Partnership Unit [Line Items]
Distributions payable		$ 26,500,000
Class A Units [Member]
Earnings Per Common Partnership Unit [Line Items]
Redeemable Limited Partnership Units Potential Cash Redemption Value Closing Market Price		$ 13.66	$ 15.98		$ 14.09
Limited Partners' Capital Account, Units Outstanding		1,535,102	1,535,102		1,763,739
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
Offering Program [Member]
Earnings Per Common Partnership Unit [Line Items]
Remaining Shares Available For Sales		16,000,000
Offering Program [Member] | Maximum [Member]
Earnings Per Common Partnership Unit [Line Items]
Fees and Commissions Percentage		2.00%

Share Based Compensation, 40106

Share Based Compensation, 401(k) Plan and Deferred Compensation (Textual) (Details) - USD ($)	May. 28, 2015	Mar. 10, 2015	Feb. 01, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 23, 2015	Feb. 06, 2015	Mar. 12, 2014	Mar. 11, 2014	Feb. 25, 2013
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number				2,624,067	2,684,795
Stock-based compensation expense				$ 7,300,000	$ 6,100,000	$ 8,300,000
Stock-based compensation expense, capitalized				1,900,000	1,700,000	1,400,000
Defined Contribution Plan, Employer Discretionary Contribution Amount				$ 400,000	$ 400,000	400,000
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent				100.00%
Common shares issued for share based compensation				5,097
Number of shares to be issued under deferred compensation plan included in total shares outstanding				700,000	400,000
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				2,624,067
Stock-based compensation expense				$ 0	$ 0	700,000
Stock-based compensation expense, capitalized				0	0	100,000
Restricted Share Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense				$ 2,400,000	$ 2,700,000	3,200,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number				506,147	540,066
Vesting period				3 years
Unrecognized compensation expenses				$ 2,400,000
Weighted average period over which options will be recognized				1 year 7 months 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost				$ 700,000	$ 600,000	600,000
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				186,791
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] | Cliff Vest After Three Years [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		119,136
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights				after three years from the grant date
Share-based Compensation Arrangement by Share-based Payment Award, Cliff Vesting, Minimum				3 years
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	34,006
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights				ratably over three years
Restricted Share Awards [Member] | Vest Ratably Over Three Years [Member] | Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		2 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		33,649
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights				ratably over two years
Restricted Performance Share Units Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense				$ 4,200,000	3,200,000	4,400,000
Unrecognized compensation expenses				$ 2,000,000
Weighted average period over which options will be recognized				1 year
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost				$ 1,200,000	$ 1,100,000	800,000
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				3 year
Common shares issued for share based compensation			486,056
Dividends Payable, Amount Per Share								$ 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				555,589	392,014
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				186,395
Aggregate share-based awards awarded to executives							186,395		61,720	134,284	231,093
Restricted Performance Share Units Plan [Member] | Cliff Vest After Three Years [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]
Stock-based compensation expense				$ 100,000	$ 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				1,250,000
Stock Issued During Period, Value, Employee Stock Purchase Plan				$ 500,000	400,000	400,000
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date				15.00%
Deferred Compensation Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Deferred compensation arrangement with individual increase in compensation expense.				$ 0	$ 0	$ 200,000

Share Based Compensation, 40107

Share Based Compensation, 401(k) Plan and Deferred Compensation - Option Activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Option activity
Outstanding at beginning of year, shares	2,684,795
Exercised, shares	(10,728)
Forfeited/Expired, shares	(50,000)
Outstanding at end of year, shares	2,624,067	2,684,795
Vested/Exercisable at end of year, shares	2,624,067
Outstanding at beginning of year, Weighted Average Exercise Price	$ 15.55
Exercised, Weighted Average Exercise Price	11.89
Forfeited/Expired, Weighted Average Exercise Price	20.61
Outstanding at end of year, Weighted Average Exercise Price	15.47	$ 15.55
Vested/Exercisable at end of period, Weighted Average Exercise Price	$ 15.47
Weighted Average Remaining Contractual Term (in years)	3 years 1 month 13 days	4 years 1 month 6 days
Vested/Exercisable at end of period, Weighted Average Remaining Contractual Term (in years)	3 years 1 month 13 days
Exercised, Aggregated Intrinsic Value	$ 18,989
Outstanding at end of year, Aggregate Intrinsic Value	0
Vested/Exercisable at end of year, Aggregate Intrinsic Value	$ 0

Share Based Compensation, 40108

Share Based Compensation, 401(k) Plan and Deferred Compensation - Restricted Share Activity (Details)	12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Outstanding at end of year, Aggregate Intrinsic Value | $	$ 0
Restricted Share Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2015, shares | shares	540,066
Granted, shares | shares	186,791
Vested, shares | shares	(219,312)
Forfeited, shares | shares	(1,398)
Non-vested at December 31, 2015, shares | shares	506,147
Non-vested at January 1, 2015, Weighted Average Grant Date Fair Value | $ / shares	$ 12.21
Granted, Weighted Average Grant Date Fair Value | $ / shares	15.67
Vested, Weighted Average Grant Date Fair Value | $ / shares	11.78
Forfeited, Weighted Average Grant Date Fair Value | $ / shares	14.33
Non-vested at December 31, 2015, Weighted Average Grant Date Fair Value | $ / shares	$ 14.50
Granted, Aggregate Intrinsic Value | $	$ 2,927,538
Vested, Aggregate Intrinsic Value | $	(3,272,381)
Outstanding at end of year, Aggregate Intrinsic Value | $	$ 6,913,968

Share Based Compensation, 40109

Share Based Compensation, 401(k) Plan and Deferred Compensation - Restricted Performance Share Units (Details) - Executive Officer [Member] - Restricted Performance Share Units Plan [Member] - USD ($) $ in Thousands	Feb. 23, 2015	Mar. 12, 2014	Mar. 11, 2014	Feb. 25, 2013	Dec. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2015, shares					392,014
Granted, shares					186,395
Units Accelerated for Qualifying Retirement					(22,820)
Non-vested at December 31, 2015, shares					555,589
Units Granted	186,395	61,720	134,284	231,093
Fair Value of Units on Grant Date (in thousands)	$ 3,933	$ 1,225	$ 2,624	$ 4,137
February 25, 2013 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2015, shares					199,577
Granted, shares					0
Units Accelerated for Qualifying Retirement					(8,255)
Non-vested at December 31, 2015, shares					191,322
Measurement Period Commencement Date					Jan. 1, 2013
Measurement Period End Date					Dec. 31, 2015
March 11, 2014 RSPU Grant [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Non-vested at January 1, 2015, shares					130,717
Granted, shares					0
Units Accelerated for Qualifying Retirement					(7,562)
Non-vested at December 31, 2015, shares					123,155
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, 2015, shares					61,720
Granted, shares					0
Units Accelerated for Qualifying Retirement					0
Non-vested at December 31, 2015, 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, 2015, shares					0
Granted, shares					186,395
Units Accelerated for Qualifying Retirement					(7,003)
Non-vested at December 31, 2015, shares					179,392
Measurement Period Commencement Date					Jan. 1, 2015
Measurement Period End Date					Dec. 31, 2017

Distributions - Tax Characteris

Distributions - Tax Characteristics of Distributions (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Distributions [Abstract]
Common Share Distributions Payments of Ordinary Dividends	$ 0.36	$ 0.41	$ 0.52
Common Share Distributions Capital Gain	0.14	0.02	0
Common Share Distributions Non-taxable Distributions	0.10	0.17	0.08
Common Stock, Dividends, Per Share, Declared	$ 0.60	$ 0.60	$ 0.60
Percentage Of Distributions classified as ordinary income	59.10%	69.00%	87.00%
Percentage Of Distributions classified as capital gain	23.50%	3.30%	0.00%
Percentage Of Distributions classified as non-taxable distribution	17.40%	27.70%	13.00%
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, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)	Aug. 27, 2010USD ($)	Nov. 17, 2008ft²
Tax Credit Carryforward [Line Items]
Tax credit transaction income			$ (19,955)	$ (11,853)	$ (11,853)
Deferred Costs			$ 101,419	101,261
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)
Contribution allocated in non controlling interest				3,000
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			$ 1,100	1,100	$ 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	500
Historic Tax Credit Transaction [Member] | U S B [Member]
Tax Credit Carryforward [Line Items]
Agreed contribution in project cost						$ 64,100
USB contributions			$ 0	15,100
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	5,300
New Markets Tax Credit Transaction [Member] | U S B [Member]
Tax Credit Carryforward [Line Items]
USB contributions			$ 13,300	$ 13,000

Accumulated Other Comprehens112

Accumulated Other Comprehensive Income (Loss) - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		$ (4,607)
Change during year		(1,010)	$ (1,190)	$ 12,789
Settlement of interest rate swaps		0	(828)	0
Reclassification of realized losses on derivative financial instruments to operations, net	[1]	420	388	286
Balance at December 31,		(5,192)	(4,607)
BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		(5,007)
Change during year		(1,010)	(1,190)	12,789
Settlement of interest rate swaps		0	(828)	0
Reclassification of realized losses on derivative financial instruments to operations, net	[2]	420	388	286
Balance at December 31,		(5,597)	(5,007)
Accumulated Other Comprehensive Income (Loss) [Member]
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		(4,607)	(2,995)	(15,918)
Change during year		(1,010)	(1,190)	12,789
Allocation of unrealized (gains)/losses on derivative financial instruments to non-controlling interests		5	18	(152)
Settlement of interest rate swaps			(828)
Reclassification of realized losses on derivative financial instruments to operations, net		420	388	286
Balance at December 31,		(5,192)	(4,607)	(2,995)
Accumulated Other Comprehensive Income (Loss) [Member] | BRANDYWINE OPERATING PARTNERSHIP, L.P.
Schedule of Accumulated other comprehensive income (loss) [Line Items]
Balance at January 1		(5,007)	(3,377)	(16,452)
Change during year		(1,010)	(1,190)	12,789
Settlement of interest rate swaps			(828)
Reclassification of realized losses on derivative financial instruments to operations, net		420	388	286
Balance at December 31,		$ (5,597)	$ (5,007)	$ (3,377)
[1]	(1) Amounts reclassified from comprehensive income to interest expense within the Consolidated Statements of Operations.
[2]	(1) Amounts reclassified from comprehensive income to interest expense within the Consolidated Statement of Operations.

Accumulated Other Comprehens113

Accumulated Other Comprehensive Income (Loss) (Textual) (Details) $ in Millions	Dec. 31, 2015USD ($)
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	$ 1.1

Segment Information (Textual) (

Segment Information (Textual) (Details)	12 Months Ended
	Dec. 31, 2015propertysegment
Segment Reporting Information [Line Items]
Number of Reportable Segments | segment	7
Number of Properties	179
Durham, NC [Member]
Segment Reporting Information [Line Items]
Number of Properties	1

Segment Information - Real Esta

Segment Information - Real Estate Investments (Details) - USD ($) $ in Thousands		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Operating properties		$ 3,693,000		$ 4,603,692		$ 4,669,289
Assets held for sale		794,588	[1]	27,436	[1]	0
Construction-in-progress		268,983		201,360
Land inventory		130,479		90,603
Operating Segments [Member]
Segment Reporting Information [Line Items]
Operating properties		3,693,000		4,603,692		4,669,289
Operating Properties		4,487,588		4,631,128		4,669,289
Operating Segments [Member] | Held for Sale Properties Included in Continuing Operations [Member]
Segment Reporting Information [Line Items]
Assets held for sale	[2],[3]	794,588		27,436		0
Operating Segments [Member] | Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Operating properties	[2]	1,157,667		1,338,655		1,300,666
Operating Segments [Member] | Pennsylvania [Member]
Segment Reporting Information [Line Items]
Operating properties	[3]	1,019,280		1,178,470		1,199,105
Operating Segments [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Operating properties	[3]	1,129,206		1,183,652		1,214,965
Operating Segments [Member] | New Jersey/ Delaware [Member]
Segment Reporting Information [Line Items]
Operating properties	[3]	154,326		392,581		414,716
Operating Segments [Member] | Richmond, Virginia [Member]
Segment Reporting Information [Line Items]
Operating properties	[3]	0		317,076		310,397
Operating Segments [Member] | California [Member]
Segment Reporting Information [Line Items]
Operating properties		68,003		193,258		192,584
Operating Segments [Member] | Austin, Texas [Member]
Segment Reporting Information [Line Items]
Operating properties	[4]	164,518		0		36,856
Corporate [Member]
Segment Reporting Information [Line Items]
Construction-in-progress		268,983		201,360		74,174
Land inventory		$ 130,479		$ 90,603		$ 93,351
[1]	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.
[2]	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.
[3]	As of December 31, 2015, the 58 properties associated with the transaction 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 21, “Subsequent Events,” for further information regarding the disposition.
[4]	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, 2015. See Note 3, "Real Estate Investments," for further information regarding this transaction.

Segment Information - Real E116

Segment Information - Real Estate Investments (Parentheticals) (Details)	Dec. 31, 2015property	Jun. 22, 2015
Segment Reporting Information [Line Items]
Number of Properties	179
Broadmoor Austin Associates [Member]
Segment Reporting Information [Line Items]
Percentage of ownership interests		50.00%
Cira Square [Member] | Held for Sale Properties Included in Continuing Operations [Member]
Segment Reporting Information [Line Items]
Number of Properties	58

Segment Information - Net Opera

Segment Information - Net Operating Income (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Total revenue		$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 147,810	$ 146,558	$ 150,500	$ 152,114	$ 602,631	$ 596,982	$ 562,210
Operating expenses	[1]									(238,087)	(235,965)	(221,769)
Net operating income										364,544	361,017	340,441
Operating Segments [Member] | Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Total revenue										209,298	201,809	146,081
Operating expenses	[1]									(77,352)	(75,262)	(55,702)
Net operating income										131,946	126,547	90,379
Operating Segments [Member] | Pennsylvania [Member]
Segment Reporting Information [Line Items]
Total revenue										158,398	160,630	153,426
Operating expenses	[1]									(57,319)	(55,062)	(54,506)
Net operating income										101,079	105,568	98,920
Operating Segments [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Total revenue										110,657	113,834	116,048
Operating expenses	[1]									(44,294)	(43,399)	(42,641)
Net operating income										66,363	70,435	73,407
Operating Segments [Member] | New Jersey/ Delaware [Member]
Segment Reporting Information [Line Items]
Total revenue										47,726	60,403	60,262
Operating expenses	[1]									(26,854)	(31,650)	(29,981)
Net operating income										20,872	28,753	30,281
Operating Segments [Member] | Richmond, Virginia [Member]
Segment Reporting Information [Line Items]
Total revenue										36,486	34,180	35,058
Operating expenses	[1]									(15,073)	(15,399)	(14,916)
Net operating income										21,413	18,781	20,142
Operating Segments [Member] | California [Member]
Segment Reporting Information [Line Items]
Total revenue										14,587	19,388	18,369
Operating expenses	[1]									(7,677)	(10,165)	(9,411)
Net operating income										6,910	9,223	8,958
Operating Segments [Member] | Austin, Texas [Member]
Segment Reporting Information [Line Items]
Total revenue	[2]									20,910	5,610	31,451
Operating expenses	[1],[2]									(8,010)	(3,223)	(13,298)
Net operating income	[2]									12,900	2,387	18,153
Corporate [Member]
Segment Reporting Information [Line Items]
Total revenue										4,569	1,128	1,515
Operating expenses	[1]									(1,508)	(1,805)	(1,314)
Net operating income										$ 3,061	$ (677)	$ 201
[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, 2015. See Note 3, "Real Estate Investments," for further information regarding these transactions.

Segment Information - Unconsoli

Segment Information - Unconsolidated Real Estate Ventures (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		$ 241,004	$ 225,004	$ 180,512
Equity in income (loss) of Real Estate Ventures		(811)	(790)	3,664
Operating Segments [Member] | Philadelphia CBD [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[1]	44,089	27,137	19,975
Equity in income (loss) of Real Estate Ventures	[1]	(188)	46	1,547
Operating Segments [Member] | Pennsylvania [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		16,408	17,385	17,272
Equity in income (loss) of Real Estate Ventures		310	(777)	925
Operating Segments [Member] | Metropolitan DC [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[2]	118,422	73,127	59,905
Equity in income (loss) of Real Estate Ventures	[2]	(336)	(317)	130
Operating Segments [Member] | New Jersey/ Delaware [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		0	0	0
Equity in income (loss) of Real Estate Ventures		348	989	1,245
Operating Segments [Member] | Richmond, Virginia [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity		1,657	1,574	1,400
Equity in income (loss) of Real Estate Ventures		582	349	381
Operating Segments [Member] | Austin, Texas [Member]
Segment Reporting Information [Line Items]
Investment in Real Estate Ventures, at equity	[3],[4]	60,428	105,781	81,960
Equity in income (loss) of Real Estate Ventures	[3],[4]	$ (1,527)	$ (1,080)	$ (564)
[1]	evo at Cira was placed into service during the third quarter ended September 30, 2014.
[2]	Investment in real estate ventures as of December 31, 2015 includes the JBG Ventures, which were formed on May 29, 2015.
[3]	Investment in real estate ventures does not include the $1.1 million and $1.2 million negative investment balance in one real estate venture as of December 31, 2015 and December 31, 2014, respectively, which is included in other liabilities.
[4]	On June 22, 2015 the Company acquired the remaining 50.0% of the common interest in Broadmoor Austin Associates. As such, the equity method investment at December 31, 2015 related to the Austin Venture only. See Note 3, "Real Estate Investments," for further information regarding the purchase of Broadmoor Austin Associates.

Segment Information - Uncons119

Segment Information - Unconsolidated Real Estate Ventures (Parentheticals) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Other liabilities	$ 31,379	$ 37,558
Coppell Associates [Member]
Segment Reporting Information [Line Items]
Other liabilities	$ 1,100	$ 1,200

Segment Information - Reconcili

Segment Information - Reconciliation of Consolidated Net Operating Income to Consolidated Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting [Abstract]
Consolidated net operating income									$ 364,544	$ 361,017	$ 340,441
Less:
Interest expense									(110,717)	(124,329)	(121,937)
Interest expense - amortization of deferred financing costs									(4,557)	(5,148)	(4,676)
Interest expense - financing obligation									(1,237)	(1,144)	(972)
Depreciation and amortization									(219,029)	(208,569)	(197,021)
General and administrative expenses									(29,406)	(26,779)	(27,628)
Equity in income (loss) of Real Estate Ventures									(811)	(790)	3,664
Provision for impairment									(82,208)	(1,765)	0
Plus:
Interest income									1,224	3,974	1,044
Tax credit transaction income									19,955	11,853	11,853
Recognized hedge activity									0	(828)	0
Net gain from remeasurement of investments in real estate ventures									758	458	6,866
Net gain on disposition of real estate									20,496	4,901	0
Net gain (loss) on sale of undepreciated real estate									3,019	1,184	(137)
Net gain (loss) on real estate venture transactions									7,229	(417)	29,604
Loss on early extinguishment of debt									0	(7,594)	(2,119)
Income (loss) from continuing operations									(30,740)	6,024	38,982
Income from discontinued operations									0	918	4,207
Net income (loss)	$ (62,700)	$ 20,308	$ 3,058	$ 8,594	$ (1,869)	$ 8,882	$ 2,174	$ (2,245)	$ (30,740)	$ 6,942	$ 43,189

Operating Leases - Minimum Futu

Operating Leases - Minimum Future Rentals on Non-cancelable Leases of Company properties leased to Tenants (Details) $ in Thousands	Dec. 31, 2015USD ($)
Operating Leases, Future Minimum Payments Receivable [Abstract]
2,016	$ 448,798
2,017	425,828
2,018	394,055
2,019	349,315
2,020	307,163
Thereafter	$ 1,500,760

Commitments and Contingencie122

Commitments and Contingencies (Textual) (Details) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2004USD ($)	Dec. 31, 2015USD ($)ft²	Dec. 03, 2015USD ($)	Dec. 31, 2014USD ($)
Property Subject to or Available for Operating Lease [Line Items]
Associated letter of credit		$ 10		$ 0
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		$ 2.9
Liability related to acquisition of TRC	$ 0.7	$ 2
Agreed holding period (not to sell) for properties acquired as part of the TRC acquisition		15 years
Subaru of America [Member]
Property Subject to or Available for Operating Lease [Line Items]
NTE Amount			$ 77.3
One Commerce Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Tax guarantee obligation		$ 125
Two Commerce Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Tax guarantee obligation		$ 100
Prentiss Properties Trust [Member] | Commerce Square [Member]
Property Subject to or Available for Operating Lease [Line Items]
Non-controlling interest, ownership percentage by non-controlling Owners		1.00%
Minimum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms		5 years
Maximum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease terms		75 years

Commitments and Contingencies -

Commitments and Contingencies - Minimum Future Rental Payments on Non-cancelable Leases (Details) $ in Thousands	Dec. 31, 2015USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,016	$ 1,385
2,017	1,385
2,018	1,385
2,019	1,385
2,020	1,385
Thereafter	67,229
Total	$ 74,154

Subsequent Events (Textual) (De

Subsequent Events (Textual) (Details) $ in Thousands	Feb. 05, 2016USD ($)ft²	Feb. 04, 2016USD ($)ft²property	Jan. 14, 2016USD ($)	Feb. 26, 2016segment	Dec. 31, 2015USD ($)ft²propertysegment	Dec. 31, 2014USD ($)ft²property	Dec. 31, 2013USD ($)ft²property
Subsequent Event [Line Items]
Rentable Square Feet | ft²					4,300,000
Proceeds from the sale of properties					$ 247,228	$ 118,855	$ 423,480
Gain on sale of properties					$ 23,515	6,085	29,166
Write off of Deferred Debt Issuance Cost						152	40
Number of Properties | property					179
Number of Reportable Segments | segment					7
Cira Square [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Debt Instrument Maturity Date					Sep. 10, 2030
Cira South Garage [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Debt Instrument Maturity Date					Sep. 10, 2030
Och Ziff Properties [Member]
Subsequent Event [Line Items]
Percentage of property management fee		2.50%
Office Building [Member]
Subsequent Event [Line Items]
Sales Price					$ 374,600	$ 101,150	$ 491,825
Rentable Square Feet | ft²					2,649,926	645,273	2,472,036
Proceeds from the sale of properties					$ 340,098	$ 113,024	$ 418,547
Number of Properties | property					27	8	21
Subsequent Event [Member]
Subsequent Event [Line Items]
Number of Reportable Segments | segment				4
Subsequent Event [Member] | Cira Square [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Repayments of debt			$ 221,400
Principal repayment of debt			176,800
Repayment of prepayment charges			44,500
Repayment of accrued interest			100
Subsequent Event [Member] | Cira South Garage [Member] | Secured Debt [Member]
Subsequent Event [Line Items]
Repayments of debt			44,500
Principal repayment of debt			35,400
Repayment of prepayment charges			8,900
Subsequent Event [Member] | Cira Square And Cira South Garage | Secured Debt [Member]
Subsequent Event [Line Items]
Write off of Deferred Debt Issuance Cost			$ 13,200
Subsequent Event [Member] | Och Ziff Properties [Member]
Subsequent Event [Line Items]
Rentable Square Feet | ft²		3,924,783
Cash proceeds from series of related transactions		$ 353,400
Number of Properties | property		58
Percentage of fee interests in land sold		100.00%
Subsequent Event [Member] | Office Building [Member] | Cira Square [Member]
Subsequent Event [Line Items]
Sales Price	$ 354,000
Rentable Square Feet | ft²	862,692
Sale of properties, closing cost	$ 3,700
Proceeds from the sale of properties	350,300
Gain on sale of properties	$ 113,400
Property management fee, description			The transaction agreements provide for the purchaser to engage the Company’s management company subsidiary to provide customary property management services for the property with an annual management fee (exclusive of expense reimbursement) not to exceed 1.5% of annual gross revenues of the property.
Property management fee, agreement term			10 years
Property management fee, maximum years required to entitle management fee			7 years
Subsequent Event [Member] | Office Building [Member] | Cira Square [Member] | Maximum [Member]
Subsequent Event [Line Items]
Percentage of property management fee			1.50%

Summary of Quarterly Results (D

Summary of Quarterly Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information Disclosure [Abstract]
Total revenue	$ 153,992	$ 152,585	$ 145,648	$ 150,406	$ 147,810	$ 146,558	$ 150,500	$ 152,114	$ 602,631	$ 596,982	$ 562,210
Net income (loss)	(62,700)	20,308	3,058	8,594	(1,869)	8,882	2,174	(2,245)	(30,740)	6,942	43,189
Net income (loss) allocated to Common Shares	$ (63,941)	$ 18,346	$ 1,255	$ 6,710	$ (3,585)	$ 6,967	$ 385	$ (4,041)	$ (30,401)	$ 6,975	$ 42,777
Basic earnings (loss) per Common Share	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	$ (0.21)	$ 0	$ 0.23
Diluted earnings (loss) per Common Share	$ (0.37)	$ 0.10	$ 0.01	$ 0.04	$ (0.02)	$ 0.04	$ 0	$ (0.03)	$ (0.21)	$ 0	$ 0.23

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, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance at Beginning of Period	$ 15,347	$ 16,248	$ 16,646
Valuation Allowances and Reserves, Additions	2,640	790	1,384
Valuation Allowances and Reserves, Deductions	1,809	1,691	1,782
Valuation Allowances and Reserves, Balance at End of Period	$ 16,178	$ 15,347	$ 16,248

Schedule III - Real Estate a127

Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 562,695
Initial Cost [Abstract]
Land	589,391
Buildings and Improvements	3,246,749
Net Improvements (Retirements) Since Acquisition	651,448
Carrying Amount at Which Carried [Abstract]
Land	619,181
Buildings and Improvements	3,868,407
Total	4,487,588	$ 4,631,128	$ 4,669,289	$ 4,726,169
Accumulated Depreciation at December 31, 2015	1,080,616	$ 1,078,996	$ 983,808	$ 954,665
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, 2015	$ 6,357
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	3,896
Carrying Amount at Which Carried [Abstract]
Land	2,206
Buildings and Improvements	17,318
Total	19,524
Accumulated Depreciation at December 31, 2015	$ 8,603
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	5,056
Carrying Amount at Which Carried [Abstract]
Land	2,611
Buildings and Improvements	15,501
Total	18,112
Accumulated Depreciation at December 31, 2015	$ 8,686
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	3,533
Carrying Amount at Which Carried [Abstract]
Land	2,595
Buildings and Improvements	15,342
Total	17,937
Accumulated Depreciation at December 31, 2015	$ 7,454
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	2,178
Carrying Amount at Which Carried [Abstract]
Land	1,533
Buildings and Improvements	11,638
Total	13,171
Accumulated Depreciation at December 31, 2015	$ 5,846
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	2,978
Carrying Amount at Which Carried [Abstract]
Land	2,086
Buildings and Improvements	11,320
Total	13,406
Accumulated Depreciation at December 31, 2015	$ 3,952
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	1,948
Carrying Amount at Which Carried [Abstract]
Land	1,180
Buildings and Improvements	9,238
Total	10,418
Accumulated Depreciation at December 31, 2015	$ 4,696
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, 2015	$ 3,689
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	1,272
Carrying Amount at Which Carried [Abstract]
Land	1,695
Buildings and Improvements	8,051
Total	9,746
Accumulated Depreciation at December 31, 2015	$ 2,847
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] | 980 Harvest Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,079
Buildings and Improvements	8,315
Net Improvements (Retirements) Since Acquisition	149
Carrying Amount at Which Carried [Abstract]
Land	1,949
Buildings and Improvements	8,594
Total	10,543
Accumulated Depreciation at December 31, 2015	$ 3,069
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] | 910 Harvest Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,225
Buildings and Improvements	8,645
Net Improvements (Retirements) Since Acquisition	(718)
Carrying Amount at Which Carried [Abstract]
Land	1,225
Buildings and Improvements	7,927
Total	9,152
Accumulated Depreciation at December 31, 2015	$ 4,822
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] | 925 Harvest Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,671
Buildings and Improvements	6,606
Net Improvements (Retirements) Since Acquisition	913
Carrying Amount at Which Carried [Abstract]
Land	1,671
Buildings and Improvements	7,519
Total	9,190
Accumulated Depreciation at December 31, 2015	$ 3,539
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] | 920 Harvest Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,208
Buildings and Improvements	6,595
Net Improvements (Retirements) Since Acquisition	(427)
Carrying Amount at Which Carried [Abstract]
Land	1,208
Buildings and Improvements	6,168
Total	7,376
Accumulated Depreciation at December 31, 2015	$ 2,892
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] | 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	318
Carrying Amount at Which Carried [Abstract]
Land	6,237
Buildings and Improvements	15,730
Total	21,967
Accumulated Depreciation at December 31, 2015	$ 1,215
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, 2015	$ 3,621
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	1,852
Carrying Amount at Which Carried [Abstract]
Land	4,241
Buildings and Improvements	18,431
Total	22,672
Accumulated Depreciation at December 31, 2015	$ 8,115
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] | One Progress Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,399
Buildings and Improvements	5,629
Net Improvements (Retirements) Since Acquisition	3,802
Carrying Amount at Which Carried [Abstract]
Land	1,127
Buildings and Improvements	9,703
Total	10,830
Accumulated Depreciation at December 31, 2015	$ 4,883
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 500 Enterprise Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,303
Buildings and Improvements	5,188
Net Improvements (Retirements) Since Acquisition	3,709
Carrying Amount at Which Carried [Abstract]
Land	1,303
Buildings and Improvements	8,897
Total	10,200
Accumulated Depreciation at December 31, 2015	$ 4,624
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] | 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	4,760
Carrying Amount at Which Carried [Abstract]
Land	4,222
Buildings and Improvements	21,651
Total	25,873
Accumulated Depreciation at December 31, 2015	$ 10,262
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] | 555 Croton Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,486
Buildings and Improvements	17,943
Net Improvements (Retirements) Since Acquisition	(228)
Carrying Amount at Which Carried [Abstract]
Land	4,024
Buildings and Improvements	18,177
Total	22,201
Accumulated Depreciation at December 31, 2015	$ 7,337
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
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	12,595
Carrying Amount at Which Carried [Abstract]
Land	2,898
Buildings and Improvements	16,561
Total	19,459
Accumulated Depreciation at December 31, 2015	$ 6,083
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	3,700
Carrying Amount at Which Carried [Abstract]
Land	2,770
Buildings and Improvements	14,714
Total	17,484
Accumulated Depreciation at December 31, 2015	$ 8,116
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	1,912
Carrying Amount at Which Carried [Abstract]
Land	2,772
Buildings and Improvements	12,848
Total	15,620
Accumulated Depreciation at December 31, 2015	$ 5,898
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	3,585
Carrying Amount at Which Carried [Abstract]
Land	2,712
Buildings and Improvements	14,538
Total	17,250
Accumulated Depreciation at December 31, 2015	$ 6,418
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	1,991
Carrying Amount at Which Carried [Abstract]
Land	2,773
Buildings and Improvements	13,135
Total	15,908
Accumulated Depreciation at December 31, 2015	$ 6,403
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, 2015	$ 7,618
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, 2015	$ 6,079
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	2,477
Carrying Amount at Which Carried [Abstract]
Land	2,017
Buildings and Improvements	10,547
Total	12,564
Accumulated Depreciation at December 31, 2015	$ 5,363
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	1,655
Carrying Amount at Which Carried [Abstract]
Land	1,916
Buildings and Improvements	6,033
Total	7,949
Accumulated Depreciation at December 31, 2015	$ 3,129
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] | 500 North Gulph Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,303
Buildings and Improvements	5,201
Net Improvements (Retirements) Since Acquisition	1,445
Carrying Amount at Which Carried [Abstract]
Land	1,303
Buildings and Improvements	6,646
Total	7,949
Accumulated Depreciation at December 31, 2015	$ 3,577
Real Estate And Accumulated Depreciation Construction Year	1,979
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 620 Allendale Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,020
Buildings and Improvements	3,839
Net Improvements (Retirements) Since Acquisition	628
Carrying Amount at Which Carried [Abstract]
Land	1,020
Buildings and Improvements	4,467
Total	5,487
Accumulated Depreciation at December 31, 2015	$ 2,132
Real Estate And Accumulated Depreciation Construction Year	1,961
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, 2015	$ 2,166
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] | 660 Allendale Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	396
Buildings and Improvements	948
Net Improvements (Retirements) Since Acquisition	2,957
Carrying Amount at Which Carried [Abstract]
Land	1,085
Buildings and Improvements	3,216
Total	4,301
Accumulated Depreciation at December 31, 2015	$ 1,219
Real Estate And Accumulated Depreciation Construction Year	2,011
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 640 Allendale Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	439
Buildings and Improvements	432
Net Improvements (Retirements) Since Acquisition	1,507
Carrying Amount at Which Carried [Abstract]
Land	439
Buildings and Improvements	1,939
Total	2,378
Accumulated Depreciation at December 31, 2015	$ 808
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] | 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, 2015	$ 3,665
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	(374)
Carrying Amount at Which Carried [Abstract]
Land	1,108
Buildings and Improvements	4,781
Total	5,889
Accumulated Depreciation at December 31, 2015	$ 1,939
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	997
Carrying Amount at Which Carried [Abstract]
Land	1,112
Buildings and Improvements	5,064
Total	6,176
Accumulated Depreciation at December 31, 2015	$ 2,116
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	247
Carrying Amount at Which Carried [Abstract]
Land	1,164
Buildings and Improvements	4,143
Total	5,307
Accumulated Depreciation at December 31, 2015	$ 1,519
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	478
Carrying Amount at Which Carried [Abstract]
Land	787
Buildings and Improvements	3,790
Total	4,577
Accumulated Depreciation at December 31, 2015	$ 1,649
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	16,709
Carrying Amount at Which Carried [Abstract]
Land	6,199
Buildings and Improvements	32,840
Total	39,039
Accumulated Depreciation at December 31, 2015	$ 11,265
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] | 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	1,484
Carrying Amount at Which Carried [Abstract]
Land	4,373
Buildings and Improvements	26,030
Total	30,403
Accumulated Depreciation at December 31, 2015	$ 5,570
Real Estate And Accumulated Depreciation Construction Year	2,006
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	3,375
Carrying Amount at Which Carried [Abstract]
Land	3,651
Buildings and Improvements	17,889
Total	21,540
Accumulated Depreciation at December 31, 2015	$ 6,508
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	1,985
Carrying Amount at Which Carried [Abstract]
Land	3,652
Buildings and Improvements	17,273
Total	20,925
Accumulated Depreciation at December 31, 2015	$ 5,902
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	997
Carrying Amount at Which Carried [Abstract]
Land	3,558
Buildings and Improvements	15,740
Total	19,298
Accumulated Depreciation at December 31, 2015	$ 5,537
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	963
Carrying Amount at Which Carried [Abstract]
Land	3,572
Buildings and Improvements	15,398
Total	18,970
Accumulated Depreciation at December 31, 2015	$ 5,551
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	19,418
Carrying Amount at Which Carried [Abstract]
Land	5,405
Buildings and Improvements	23,194
Total	28,599
Accumulated Depreciation at December 31, 2015	$ 2,357
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] | 2240/2250 Butler Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,104
Buildings and Improvements	4,627
Net Improvements (Retirements) Since Acquisition	1,312
Carrying Amount at Which Carried [Abstract]
Land	1,104
Buildings and Improvements	5,939
Total	7,043
Accumulated Depreciation at December 31, 2015	$ 3,888
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 2260 Butler Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	662
Buildings and Improvements	2,727
Net Improvements (Retirements) Since Acquisition	2,009
Carrying Amount at Which Carried [Abstract]
Land	550
Buildings and Improvements	4,848
Total	5,398
Accumulated Depreciation at December 31, 2015	$ 2,460
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 120 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	685
Buildings and Improvements	2,773
Net Improvements (Retirements) Since Acquisition	667
Carrying Amount at Which Carried [Abstract]
Land	685
Buildings and Improvements	3,440
Total	4,125
Accumulated Depreciation at December 31, 2015	$ 1,861
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 years
PENNSYLVANIA SUBURBS [Member] | 140 West Germantown Pike [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	482
Buildings and Improvements	1,976
Net Improvements (Retirements) Since Acquisition	282
Carrying Amount at Which Carried [Abstract]
Land	482
Buildings and Improvements	2,258
Total	2,740
Accumulated Depreciation at December 31, 2015	$ 1,181
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,996
Depreciable Life (Years)	40 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
Carrying Amount at Which Carried [Abstract]
Land	1,043
Buildings and Improvements	555
Total	1,598
Accumulated Depreciation at December 31, 2015	$ 149
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	12,574
Carrying Amount at Which Carried [Abstract]
Land	11,897
Buildings and Improvements	49,588
Total	61,485
Accumulated Depreciation at December 31, 2015	$ 18,681
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	23,135
Carrying Amount at Which Carried [Abstract]
Land	7,323
Buildings and Improvements	51,748
Total	59,071
Accumulated Depreciation at December 31, 2015	$ 21,189
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	4,530
Carrying Amount at Which Carried [Abstract]
Land	8,949
Buildings and Improvements	34,348
Total	43,297
Accumulated Depreciation at December 31, 2015	$ 16,172
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	16,414
Carrying Amount at Which Carried [Abstract]
Land	8,609
Buildings and Improvements	32,327
Total	40,936
Accumulated Depreciation at December 31, 2015	$ 13,850
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	14,393
Carrying Amount at Which Carried [Abstract]
Land	5,705
Buildings and Improvements	35,484
Total	41,189
Accumulated Depreciation at December 31, 2015	$ 11,578
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	5,512
Carrying Amount at Which Carried [Abstract]
Land	6,578
Buildings and Improvements	30,965
Total	37,543
Accumulated Depreciation at December 31, 2015	$ 9,253
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	2,540
Carrying Amount at Which Carried [Abstract]
Land	4,791
Buildings and Improvements	20,483
Total	25,274
Accumulated Depreciation at December 31, 2015	$ 9,029
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	3,883
Carrying Amount at Which Carried [Abstract]
Land	3,942
Buildings and Improvements	19,362
Total	23,304
Accumulated Depreciation at December 31, 2015	$ 7,797
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, 2015	$ 4,895
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	2,486
Carrying Amount at Which Carried [Abstract]
Land	2,509
Buildings and Improvements	10,638
Total	13,147
Accumulated Depreciation at December 31, 2015	$ 3,488
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
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, 2015	$ 239
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	3,483
Carrying Amount at Which Carried [Abstract]
Land	6,251
Buildings and Improvements	28,692
Total	34,943
Accumulated Depreciation at December 31, 2015	$ 8,481
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	3,069
Carrying Amount at Which Carried [Abstract]
Land	3,557
Buildings and Improvements	17,318
Total	20,875
Accumulated Depreciation at December 31, 2015	$ 4,089
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] | 2970 Market Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 177,425
Initial Cost [Abstract]
Land	22,430
Buildings and Improvements	217,763
Net Improvements (Retirements) Since Acquisition	25,597
Carrying Amount at Which Carried [Abstract]
Land	22,430
Buildings and Improvements	243,360
Total	265,790
Accumulated Depreciation at December 31, 2015	$ 34,339
Real Estate And Accumulated Depreciation Construction Year	2,010
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | 2929 Arch Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Buildings and Improvements	208,570
Net Improvements (Retirements) Since Acquisition	27,724
Carrying Amount at Which Carried [Abstract]
Land	12,586
Buildings and Improvements	223,708
Total	236,294
Accumulated Depreciation at December 31, 2015	$ 93,087
Real Estate And Accumulated Depreciation Construction Year	2,005
Depreciable Life (Years)	40 years
Philadelphia CBD [Member] | 1717 Arch Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Buildings and Improvements	98,188
Net Improvements (Retirements) Since Acquisition	68,523
Carrying Amount at Which Carried [Abstract]
Land	25,195
Buildings and Improvements	141,516
Total	166,711
Accumulated Depreciation at December 31, 2015	$ 26,182
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] | 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	17,323
Carrying Amount at Which Carried [Abstract]
Land	15,323
Buildings and Improvements	137,523
Total	152,846
Accumulated Depreciation at December 31, 2015	$ 7,332
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] | 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	27,407
Carrying Amount at Which Carried [Abstract]
Land	14,473
Buildings and Improvements	135,166
Total	149,639
Accumulated Depreciation at December 31, 2015	$ 41,218
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] | 100 North 18th Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 86,886
Initial Cost [Abstract]
Land	16,066
Buildings and Improvements	100,255
Net Improvements (Retirements) Since Acquisition	12,834
Carrying Amount at Which Carried [Abstract]
Land	16,066
Buildings and Improvements	113,089
Total	129,155
Accumulated Depreciation at December 31, 2015	$ 33,526
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] | 2005 Market Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 130,000
Initial Cost [Abstract]
Land	15,161
Buildings and Improvements	105,021
Net Improvements (Retirements) Since Acquisition	14,907
Carrying Amount at Which Carried [Abstract]
Land	15,161
Buildings and Improvements	119,928
Total	135,089
Accumulated Depreciation at December 31, 2015	$ 6,783
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	$ 35,546
Initial Cost [Abstract]
Buildings and Improvements	76,008
Net Improvements (Retirements) Since Acquisition	2,538
Carrying Amount at Which Carried [Abstract]
Buildings and Improvements	78,546
Total	78,546
Accumulated Depreciation at December 31, 2015	$ 10,467
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	17,545
Carrying Amount at Which Carried [Abstract]
Land	7,768
Buildings and Improvements	34,808
Total	42,576
Accumulated Depreciation at December 31, 2015	$ 2,093
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]
Buildings and Improvements	21,417
Net Improvements (Retirements) Since Acquisition	7,975
Carrying Amount at Which Carried [Abstract]
Buildings and Improvements	29,392
Total	29,392
Accumulated Depreciation at December 31, 2015	$ 4,685
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] | 101-103 Juniper Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
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, 2015	$ 2,390
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	3,444
Carrying Amount at Which Carried [Abstract]
Land	628
Buildings and Improvements	5,544
Total	6,172
Accumulated Depreciation at December 31, 2015	$ 2,679
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
Carrying Amount at Which Carried [Abstract]
Land	13,365
Buildings and Improvements	5,791
Total	19,156
Accumulated Depreciation at December 31, 2015	$ 869
Real Estate And Accumulated Depreciation Construction Year	1,966
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	5 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	(5,279)
Carrying Amount at Which Carried [Abstract]
Land	1,927
Buildings and Improvements	13,286
Total	15,213
Accumulated Depreciation at December 31, 2015	$ 6,581
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	(10,493)
Carrying Amount at Which Carried [Abstract]
Land	336
Buildings and Improvements	4,060
Total	4,396
Accumulated Depreciation at December 31, 2015	$ 2,963
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	(8,534)
Carrying Amount at Which Carried [Abstract]
Land	534
Buildings and Improvements	4,310
Total	4,844
Accumulated Depreciation at December 31, 2015	$ 2,560
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]
Buildings and Improvements	37,421
Net Improvements (Retirements) Since Acquisition	10,749
Carrying Amount at Which Carried [Abstract]
Buildings and Improvements	48,170
Total	48,170
Accumulated Depreciation at December 31, 2015	$ 10,174
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] | 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	42
Carrying Amount at Which Carried [Abstract]
Land	202
Buildings and Improvements	908
Total	1,110
Accumulated Depreciation at December 31, 2015	$ 233
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] | 12015 Lee Jackson Memorial Highway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,770
Buildings and Improvements	22,895
Net Improvements (Retirements) Since Acquisition	1,902
Carrying Amount at Which Carried [Abstract]
Land	3,561
Buildings and Improvements	25,006
Total	28,567
Accumulated Depreciation at December 31, 2015	$ 7,574
Real Estate And Accumulated Depreciation Construction Year	1,985
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	42 years
Metropolitan DC [Member] | 11781 Lee Jackson Memorial Highway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,246
Buildings and Improvements	19,836
Net Improvements (Retirements) Since Acquisition	(1,435)
Carrying Amount at Which Carried [Abstract]
Land	2,615
Buildings and Improvements	19,032
Total	21,647
Accumulated Depreciation at December 31, 2015	$ 5,512
Real Estate And Accumulated Depreciation Construction Year	1,982
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	40 years
Metropolitan DC [Member] | 4401 Fair Lakes Court [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,569
Buildings and Improvements	11,982
Net Improvements (Retirements) Since Acquisition	(2,098)
Carrying Amount at Which Carried [Abstract]
Land	990
Buildings and Improvements	10,463
Total	11,453
Accumulated Depreciation at December 31, 2015	$ 2,766
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	52 years
Metropolitan DC [Member] | 3141 Fairview Park Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 20,838
Initial Cost [Abstract]
Land	5,918
Buildings and Improvements	40,981
Net Improvements (Retirements) Since Acquisition	14,119
Carrying Amount at Which Carried [Abstract]
Land	7,081
Buildings and Improvements	53,937
Total	61,018
Accumulated Depreciation at December 31, 2015	$ 11,640
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	51 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	18,280
Carrying Amount at Which Carried [Abstract]
Land	16,129
Buildings and Improvements	83,875
Total	100,004
Accumulated Depreciation at December 31, 2015	$ 31,570
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	12,524
Carrying Amount at Which Carried [Abstract]
Land	8,782
Buildings and Improvements	64,398
Total	73,180
Accumulated Depreciation at December 31, 2015	$ 15,294
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] | 196/198 Van Buren Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	7,931
Buildings and Improvements	43,812
Net Improvements (Retirements) Since Acquisition	9,059
Carrying Amount at Which Carried [Abstract]
Land	8,348
Buildings and Improvements	52,454
Total	60,802
Accumulated Depreciation at December 31, 2015	$ 11,986
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	53 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	3,367
Carrying Amount at Which Carried [Abstract]
Land	11,472
Buildings and Improvements	49,260
Total	60,732
Accumulated Depreciation at December 31, 2015	$ 11,204
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	4,612
Carrying Amount at Which Carried [Abstract]
Land	10,365
Buildings and Improvements	48,488
Total	58,853
Accumulated Depreciation at December 31, 2015	$ 13,849
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	16,028
Carrying Amount at Which Carried [Abstract]
Land	7,417
Buildings and Improvements	62,230
Total	69,647
Accumulated Depreciation at December 31, 2015	$ 10,822
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	4,556
Carrying Amount at Which Carried [Abstract]
Land	7,373
Buildings and Improvements	43,632
Total	51,005
Accumulated Depreciation at December 31, 2015	$ 9,193
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	2,688
Carrying Amount at Which Carried [Abstract]
Land	5,795
Buildings and Improvements	41,130
Total	46,925
Accumulated Depreciation at December 31, 2015	$ 8,879
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	5,317
Carrying Amount at Which Carried [Abstract]
Land	4,809
Buildings and Improvements	39,410
Total	44,219
Accumulated Depreciation at December 31, 2015	$ 8,573
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	2,126
Carrying Amount at Which Carried [Abstract]
Land	3,866
Buildings and Improvements	21,419
Total	25,285
Accumulated Depreciation at December 31, 2015	$ 5,398
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	3,740
Carrying Amount at Which Carried [Abstract]
Land	18,785
Buildings and Improvements	100,930
Total	119,715
Accumulated Depreciation at December 31, 2015	$ 19,257
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	2,227
Carrying Amount at Which Carried [Abstract]
Land	8,102
Buildings and Improvements	36,041
Total	44,143
Accumulated Depreciation at December 31, 2015	$ 7,898
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	4,638
Carrying Amount at Which Carried [Abstract]
Land	5,237
Buildings and Improvements	35,678
Total	40,915
Accumulated Depreciation at December 31, 2015	$ 10,292
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	7,413
Carrying Amount at Which Carried [Abstract]
Land	5,154
Buildings and Improvements	36,986
Total	42,140
Accumulated Depreciation at December 31, 2015	$ 9,057
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	17,817
Carrying Amount at Which Carried [Abstract]
Land	4,733
Buildings and Improvements	44,685
Total	49,418
Accumulated Depreciation at December 31, 2015	$ 7,715
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	11,469
Carrying Amount at Which Carried [Abstract]
Land	7,944
Buildings and Improvements	59,139
Total	67,083
Accumulated Depreciation at December 31, 2015	$ 13,191
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	5,280
Carrying Amount at Which Carried [Abstract]
Land	4,397
Buildings and Improvements	36,084
Total	40,481
Accumulated Depreciation at December 31, 2015	$ 7,393
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	51 years
New Jersey/ Delaware [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	1,798
Carrying Amount at Which Carried [Abstract]
Land	2,069
Buildings and Improvements	10,073
Total	12,142
Accumulated Depreciation at December 31, 2015	$ 3,922
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	1,955
Carrying Amount at Which Carried [Abstract]
Land	2,144
Buildings and Improvements	10,753
Total	12,897
Accumulated Depreciation at December 31, 2015	$ 3,818
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	2,748
Carrying Amount at Which Carried [Abstract]
Land	1,645
Buildings and Improvements	9,327
Total	10,972
Accumulated Depreciation at December 31, 2015	$ 3,102
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	401
Carrying Amount at Which Carried [Abstract]
Land	769
Buildings and Improvements	3,456
Total	4,225
Accumulated Depreciation at December 31, 2015	$ 1,712
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	78
Carrying Amount at Which Carried [Abstract]
Land	244
Buildings and Improvements	1,049
Total	1,293
Accumulated Depreciation at December 31, 2015	$ 525
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	123
Carrying Amount at Which Carried [Abstract]
Land	231
Buildings and Improvements	1,044
Total	1,275
Accumulated Depreciation at December 31, 2015	$ 514
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 50 East Clementon Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	114
Buildings and Improvements	964
Net Improvements (Retirements) Since Acquisition	671
Carrying Amount at Which Carried [Abstract]
Land	114
Buildings and Improvements	1,635
Total	1,749
Accumulated Depreciation at December 31, 2015	$ 584
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	16
Carrying Amount at Which Carried [Abstract]
Land	185
Buildings and Improvements	746
Total	931
Accumulated Depreciation at December 31, 2015	$ 369
Real Estate And Accumulated Depreciation Construction Year	1,974
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	16
Carrying Amount at Which Carried [Abstract]
Land	183
Buildings and Improvements	742
Total	925
Accumulated Depreciation at December 31, 2015	$ 362
Real Estate And Accumulated Depreciation Construction Year	1,974
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	57
Carrying Amount at Which Carried [Abstract]
Land	93
Buildings and Improvements	421
Total	514
Accumulated Depreciation at December 31, 2015	$ 228
Real Estate And Accumulated Depreciation Construction Year	1,972
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	3
Carrying Amount at Which Carried [Abstract]
Land	21
Buildings and Improvements	84
Total	105
Accumulated Depreciation at December 31, 2015	$ 41
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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, 2015	$ 30
Real Estate And Accumulated Depreciation Construction Year	1,968
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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, 2015	$ 1,761
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	1,437
Carrying Amount at Which Carried [Abstract]
Land	703
Buildings and Improvements	4,256
Total	4,959
Accumulated Depreciation at December 31, 2015	$ 1,760
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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, 2015	$ 1,311
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	376
Carrying Amount at Which Carried [Abstract]
Land	539
Buildings and Improvements	2,544
Total	3,083
Accumulated Depreciation at December 31, 2015	$ 1,215
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 308 Harper Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,643
Buildings and Improvements	6,663
Net Improvements (Retirements) Since Acquisition	(39)
Carrying Amount at Which Carried [Abstract]
Land	1,425
Buildings and Improvements	6,842
Total	8,267
Accumulated Depreciation at December 31, 2015	$ 3,481
Real Estate And Accumulated Depreciation Construction Year	1,976
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 1120 Executive Boulevard [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,074
Buildings and Improvements	8,415
Net Improvements (Retirements) Since Acquisition	4,280
Carrying Amount at Which Carried [Abstract]
Land	2,074
Buildings and Improvements	12,695
Total	14,769
Accumulated Depreciation at December 31, 2015	$ 5,696
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 700 East Gate Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	3,569
Buildings and Improvements	14,436
Net Improvements (Retirements) Since Acquisition	1,956
Carrying Amount at Which Carried [Abstract]
Land	3,569
Buildings and Improvements	16,392
Total	19,961
Accumulated Depreciation at December 31, 2015	$ 7,573
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 701 East Gate Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,736
Buildings and Improvements	6,877
Net Improvements (Retirements) Since Acquisition	1,163
Carrying Amount at Which Carried [Abstract]
Land	1,589
Buildings and Improvements	8,187
Total	9,776
Accumulated Depreciation at December 31, 2015	$ 4,033
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 307 Fellowship Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,565
Buildings and Improvements	6,342
Net Improvements (Retirements) Since Acquisition	306
Carrying Amount at Which Carried [Abstract]
Land	1,330
Buildings and Improvements	6,883
Total	8,213
Accumulated Depreciation at December 31, 2015	$ 3,551
Real Estate And Accumulated Depreciation Construction Year	1,981
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 305 Fellowship Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,421
Buildings and Improvements	5,768
Net Improvements (Retirements) Since Acquisition	920
Carrying Amount at Which Carried [Abstract]
Land	1,233
Buildings and Improvements	6,876
Total	8,109
Accumulated Depreciation at December 31, 2015	$ 3,340
Real Estate And Accumulated Depreciation Construction Year	1,980
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 303 Fellowship Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,493
Buildings and Improvements	6,055
Net Improvements (Retirements) Since Acquisition	205
Carrying Amount at Which Carried [Abstract]
Land	1,250
Buildings and Improvements	6,503
Total	7,753
Accumulated Depreciation at December 31, 2015	$ 3,213
Real Estate And Accumulated Depreciation Construction Year	1,979
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 309 Fellowship Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,518
Buildings and Improvements	6,154
Net Improvements (Retirements) Since Acquisition	711
Carrying Amount at Which Carried [Abstract]
Land	1,518
Buildings and Improvements	6,865
Total	8,383
Accumulated Depreciation at December 31, 2015	$ 3,206
Real Estate And Accumulated Depreciation Construction Year	1,982
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 161 Gaither Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,016
Buildings and Improvements	4,064
Net Improvements (Retirements) Since Acquisition	535
Carrying Amount at Which Carried [Abstract]
Land	1,011
Buildings and Improvements	4,604
Total	5,615
Accumulated Depreciation at December 31, 2015	$ 1,724
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,001
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 815 East Gate Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	636
Buildings and Improvements	2,584
Net Improvements (Retirements) Since Acquisition	446
Carrying Amount at Which Carried [Abstract]
Land	581
Buildings and Improvements	3,085
Total	3,666
Accumulated Depreciation at December 31, 2015	$ 1,532
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [Member] | 817 East Gate Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	611
Buildings and Improvements	2,426
Net Improvements (Retirements) Since Acquisition	216
Carrying Amount at Which Carried [Abstract]
Land	600
Buildings and Improvements	2,653
Total	3,253
Accumulated Depreciation at December 31, 2015	$ 1,247
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	96
Carrying Amount at Which Carried [Abstract]
Land	2,732
Buildings and Improvements	11,038
Total	13,770
Accumulated Depreciation at December 31, 2015	$ 11,002
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	3,360
Carrying Amount at Which Carried [Abstract]
Land	696
Buildings and Improvements	6,162
Total	6,858
Accumulated Depreciation at December 31, 2015	$ 2,035
Real Estate And Accumulated Depreciation Construction Year	1,990
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	538
Carrying Amount at Which Carried [Abstract]
Land	532
Buildings and Improvements	2,590
Total	3,122
Accumulated Depreciation at December 31, 2015	$ 1,288
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,997
Depreciable Life (Years)	40 years
New Jersey/ Delaware [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	2,707
Carrying Amount at Which Carried [Abstract]
Land	6,141
Buildings and Improvements	23,847
Total	29,988
Accumulated Depreciation at December 31, 2015	$ 8,113
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	30 years
New Jersey/ Delaware [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	2,889
Carrying Amount at Which Carried [Abstract]
Land	6,369
Buildings and Improvements	16,628
Total	22,997
Accumulated Depreciation at December 31, 2015	$ 7,496
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,004
Depreciable Life (Years)	23 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	119
Carrying Amount at Which Carried [Abstract]
Land	3,755
Buildings and Improvements	22,821
Total	26,576
Accumulated Depreciation at December 31, 2015	$ 358
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	654
Carrying Amount at Which Carried [Abstract]
Land	2,732
Buildings and Improvements	16,959
Total	19,691
Accumulated Depreciation at December 31, 2015	$ 274
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	118
Carrying Amount at Which Carried [Abstract]
Land	3,688
Buildings and Improvements	22,466
Total	26,154
Accumulated Depreciation at December 31, 2015	$ 353
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	83
Carrying Amount at Which Carried [Abstract]
Land	2,614
Buildings and Improvements	15,823
Total	18,437
Accumulated Depreciation at December 31, 2015	$ 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
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	117
Carrying Amount at Which Carried [Abstract]
Land	3,689
Buildings and Improvements	22,471
Total	26,160
Accumulated Depreciation at December 31, 2015	$ 353
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 6 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,676
Buildings and Improvements	15,972
Net Improvements (Retirements) Since Acquisition	84
Carrying Amount at Which Carried [Abstract]
Land	2,676
Buildings and Improvements	16,056
Total	18,732
Accumulated Depreciation at December 31, 2015	$ 252
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	39
Carrying Amount at Which Carried [Abstract]
Land	1,400
Buildings and Improvements	7,461
Total	8,861
Accumulated Depreciation at December 31, 2015	$ 122
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]
Buildings and Improvements	19,826
Net Improvements (Retirements) Since Acquisition	103
Carrying Amount at Which Carried [Abstract]
Buildings and Improvements	19,929
Total	19,929
Accumulated Depreciation at December 31, 2015	$ 424
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	2,015
Depreciable Life (Years)	35 years
Richmond, Virginia [Member] | 4364 South Alston Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,622
Buildings and Improvements	6,419
Net Improvements (Retirements) Since Acquisition	(454)
Carrying Amount at Which Carried [Abstract]
Land	1,144
Buildings and Improvements	6,443
Total	7,587
Accumulated Depreciation at December 31, 2015	$ 3,512
Real Estate And Accumulated Depreciation Construction Year	1,985
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 4805 Lake Brooke Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,640
Buildings and Improvements	6,567
Net Improvements (Retirements) Since Acquisition	703
Carrying Amount at Which Carried [Abstract]
Land	1,420
Buildings and Improvements	7,490
Total	8,910
Accumulated Depreciation at December 31, 2015	$ 3,576
Real Estate And Accumulated Depreciation Construction Year	1,996
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | Overlook I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	748
Buildings and Improvements	3,976
Net Improvements (Retirements) Since Acquisition	600
Carrying Amount at Which Carried [Abstract]
Land	791
Buildings and Improvements	4,533
Total	5,324
Accumulated Depreciation at December 31, 2015	$ 916
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,011
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | Overlook II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	748
Buildings and Improvements	4,492
Net Improvements (Retirements) Since Acquisition	504
Carrying Amount at Which Carried [Abstract]
Land	791
Buildings and Improvements	4,953
Total	5,744
Accumulated Depreciation at December 31, 2015	$ 923
Real Estate And Accumulated Depreciation Construction Year	2,000
Real Estate And Accumulated Depreciation Year Of Acquisition	2,011
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2812 Emerywood Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,069
Buildings and Improvements	4,281
Net Improvements (Retirements) Since Acquisition	670
Carrying Amount at Which Carried [Abstract]
Land	1,069
Buildings and Improvements	4,951
Total	6,020
Accumulated Depreciation at December 31, 2015	$ 2,290
Real Estate And Accumulated Depreciation Construction Year	1,980
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 300 Arboretum Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	5,450
Buildings and Improvements	21,892
Net Improvements (Retirements) Since Acquisition	3,831
Carrying Amount at Which Carried [Abstract]
Land	4,674
Buildings and Improvements	26,499
Total	31,173
Accumulated Depreciation at December 31, 2015	$ 12,104
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 7501 Boulders View Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,669
Buildings and Improvements	19,699
Net Improvements (Retirements) Since Acquisition	(2,770)
Carrying Amount at Which Carried [Abstract]
Land	3,920
Buildings and Improvements	17,678
Total	21,598
Accumulated Depreciation at December 31, 2015	$ 4,891
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 7300 Beaufont Springs Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,672
Buildings and Improvements	19,689
Net Improvements (Retirements) Since Acquisition	(1,080)
Carrying Amount at Which Carried [Abstract]
Land	3,980
Buildings and Improvements	19,301
Total	23,281
Accumulated Depreciation at December 31, 2015	$ 4,999
Real Estate And Accumulated Depreciation Construction Year	2,000
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 6800 Paragon Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,552
Buildings and Improvements	18,414
Net Improvements (Retirements) Since Acquisition	(681)
Carrying Amount at Which Carried [Abstract]
Land	3,821
Buildings and Improvements	18,464
Total	22,285
Accumulated Depreciation at December 31, 2015	$ 5,456
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 6802 Paragon Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,917
Buildings and Improvements	11,454
Net Improvements (Retirements) Since Acquisition	3,074
Carrying Amount at Which Carried [Abstract]
Land	2,917
Buildings and Improvements	14,528
Total	17,445
Accumulated Depreciation at December 31, 2015	$ 5,706
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	2,002
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 1025 Boulders Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,574
Buildings and Improvements	11,297
Net Improvements (Retirements) Since Acquisition	(1,314)
Carrying Amount at Which Carried [Abstract]
Land	2,040
Buildings and Improvements	10,517
Total	12,557
Accumulated Depreciation at December 31, 2015	$ 3,009
Real Estate And Accumulated Depreciation Construction Year	1,994
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2100-2116 West Laburnam Avenue [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,482
Buildings and Improvements	8,846
Net Improvements (Retirements) Since Acquisition	2,742
Carrying Amount at Which Carried [Abstract]
Land	2,482
Buildings and Improvements	11,588
Total	14,070
Accumulated Depreciation at December 31, 2015	$ 5,331
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 7401 Beaufont Springs Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,349
Buildings and Improvements	10,396
Net Improvements (Retirements) Since Acquisition	(2,048)
Carrying Amount at Which Carried [Abstract]
Land	1,788
Buildings and Improvements	8,909
Total	10,697
Accumulated Depreciation at December 31, 2015	$ 2,649
Real Estate And Accumulated Depreciation Construction Year	1,998
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 7325 Beaufont Springs Drive [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	2,344
Buildings and Improvements	10,377
Net Improvements (Retirements) Since Acquisition	(1,745)
Carrying Amount at Which Carried [Abstract]
Land	2,002
Buildings and Improvements	8,974
Total	10,976
Accumulated Depreciation at December 31, 2015	$ 2,349
Real Estate And Accumulated Depreciation Construction Year	1,999
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 9011 Arboretum Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,857
Buildings and Improvements	7,702
Net Improvements (Retirements) Since Acquisition	(430)
Carrying Amount at Which Carried [Abstract]
Land	1,501
Buildings and Improvements	7,628
Total	9,129
Accumulated Depreciation at December 31, 2015	$ 4,104
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 6806 Paragon Place [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Buildings and Improvements	10,288
Net Improvements (Retirements) Since Acquisition	(117)
Carrying Amount at Which Carried [Abstract]
Land	403
Buildings and Improvements	9,768
Total	10,171
Accumulated Depreciation at December 31, 2015	$ 2,885
Real Estate And Accumulated Depreciation Construction Year	2,007
Real Estate And Accumulated Depreciation Year Of Acquisition	2,005
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 9100 Arboretum Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,362
Buildings and Improvements	5,489
Net Improvements (Retirements) Since Acquisition	541
Carrying Amount at Which Carried [Abstract]
Land	1,274
Buildings and Improvements	6,118
Total	7,392
Accumulated Depreciation at December 31, 2015	$ 2,974
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2511 Brittons Hill Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,202
Buildings and Improvements	4,820
Net Improvements (Retirements) Since Acquisition	1,221
Carrying Amount at Which Carried [Abstract]
Land	1,202
Buildings and Improvements	6,041
Total	7,243
Accumulated Depreciation at December 31, 2015	$ 3,041
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 9200 Arboretum Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	985
Buildings and Improvements	3,973
Net Improvements (Retirements) Since Acquisition	1,275
Carrying Amount at Which Carried [Abstract]
Land	985
Buildings and Improvements	5,248
Total	6,233
Accumulated Depreciation at December 31, 2015	$ 2,562
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 9210 Arboretum Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,110
Buildings and Improvements	4,474
Net Improvements (Retirements) Since Acquisition	167
Carrying Amount at Which Carried [Abstract]
Land	970
Buildings and Improvements	4,781
Total	5,751
Accumulated Depreciation at December 31, 2015	$ 2,274
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2201-2245 Tomlynn Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,020
Buildings and Improvements	4,067
Net Improvements (Retirements) Since Acquisition	1,126
Carrying Amount at Which Carried [Abstract]
Land	1,020
Buildings and Improvements	5,193
Total	6,213
Accumulated Depreciation at December 31, 2015	$ 2,332
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 9211 Arboretum Parkway [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	582
Buildings and Improvements	2,433
Net Improvements (Retirements) Since Acquisition	317
Carrying Amount at Which Carried [Abstract]
Land	470
Buildings and Improvements	2,862
Total	3,332
Accumulated Depreciation at December 31, 2015	$ 1,395
Real Estate And Accumulated Depreciation Construction Year	1,991
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2221-2245 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	530
Buildings and Improvements	2,123
Net Improvements (Retirements) Since Acquisition	369
Carrying Amount at Which Carried [Abstract]
Land	530
Buildings and Improvements	2,492
Total	3,022
Accumulated Depreciation at December 31, 2015	$ 1,091
Real Estate And Accumulated Depreciation Construction Year	1,994
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2212-2224 Tomlynn Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	502
Buildings and Improvements	2,014
Net Improvements (Retirements) Since Acquisition	487
Carrying Amount at Which Carried [Abstract]
Land	502
Buildings and Improvements	2,501
Total	3,003
Accumulated Depreciation at December 31, 2015	$ 1,109
Real Estate And Accumulated Depreciation Construction Year	1,985
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2244 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	550
Buildings and Improvements	2,203
Carrying Amount at Which Carried [Abstract]
Land	550
Buildings and Improvements	2,203
Total	2,753
Accumulated Depreciation at December 31, 2015	$ 1,016
Real Estate And Accumulated Depreciation Construction Year	1,993
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2277 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	507
Buildings and Improvements	2,034
Net Improvements (Retirements) Since Acquisition	294
Carrying Amount at Which Carried [Abstract]
Land	507
Buildings and Improvements	2,328
Total	2,835
Accumulated Depreciation at December 31, 2015	$ 1,077
Real Estate And Accumulated Depreciation Construction Year	1,986
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2248 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	512
Buildings and Improvements	2,049
Net Improvements (Retirements) Since Acquisition	379
Carrying Amount at Which Carried [Abstract]
Land	503
Buildings and Improvements	2,437
Total	2,940
Accumulated Depreciation at December 31, 2015	$ 1,000
Real Estate And Accumulated Depreciation Construction Year	1,989
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2161-2179 Tomlynn Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	423
Buildings and Improvements	1,695
Net Improvements (Retirements) Since Acquisition	306
Carrying Amount at Which Carried [Abstract]
Land	423
Buildings and Improvements	2,001
Total	2,424
Accumulated Depreciation at December 31, 2015	$ 867
Real Estate And Accumulated Depreciation Construction Year	1,985
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2246 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	455
Buildings and Improvements	1,822
Carrying Amount at Which Carried [Abstract]
Land	455
Buildings and Improvements	1,822
Total	2,277
Accumulated Depreciation at December 31, 2015	$ 841
Real Estate And Accumulated Depreciation Construction Year	1,987
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2251 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	387
Buildings and Improvements	1,552
Net Improvements (Retirements) Since Acquisition	59
Carrying Amount at Which Carried [Abstract]
Land	387
Buildings and Improvements	1,611
Total	1,998
Accumulated Depreciation at December 31, 2015	$ 740
Real Estate And Accumulated Depreciation Construction Year	1,983
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2256 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	356
Buildings and Improvements	1,427
Net Improvements (Retirements) Since Acquisition	225
Carrying Amount at Which Carried [Abstract]
Land	356
Buildings and Improvements	1,652
Total	2,008
Accumulated Depreciation at December 31, 2015	$ 777
Real Estate And Accumulated Depreciation Construction Year	1,982
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2130-2146 Tomlynn Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	353
Buildings and Improvements	1,416
Net Improvements (Retirements) Since Acquisition	225
Carrying Amount at Which Carried [Abstract]
Land	353
Buildings and Improvements	1,641
Total	1,994
Accumulated Depreciation at December 31, 2015	$ 779
Real Estate And Accumulated Depreciation Construction Year	1,988
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2112-2124 Tomlynn Street [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	281
Buildings and Improvements	1,125
Net Improvements (Retirements) Since Acquisition	306
Carrying Amount at Which Carried [Abstract]
Land	281
Buildings and Improvements	1,431
Total	1,712
Accumulated Depreciation at December 31, 2015	$ 695
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | 2240 Dabney Road [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	264
Buildings and Improvements	1,059
Net Improvements (Retirements) Since Acquisition	88
Carrying Amount at Which Carried [Abstract]
Land	264
Buildings and Improvements	1,147
Total	1,411
Accumulated Depreciation at December 31, 2015	$ 514
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	1,998
Depreciable Life (Years)	40 years
Richmond, Virginia [Member] | Boulders Land [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	1,256
Net Improvements (Retirements) Since Acquisition	(116)
Carrying Amount at Which Carried [Abstract]
Land	1,115
Buildings and Improvements	25
Total	1,140
Accumulated Depreciation at December 31, 2015	$ 3
Real Estate And Accumulated Depreciation Year Of Acquisition	2,007
California [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	833
Carrying Amount at Which Carried [Abstract]
Land	6,515
Buildings and Improvements	25,377
Total	31,892
Accumulated Depreciation at December 31, 2015	$ 9,192
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	34 years
California [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	298
Carrying Amount at Which Carried [Abstract]
Land	6,476
Buildings and Improvements	25,264
Total	31,740
Accumulated Depreciation at December 31, 2015	$ 8,869
Real Estate And Accumulated Depreciation Construction Year	1,984
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006
Depreciable Life (Years)	34 years
California [Member] | Oakland Lot B [Member]
Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	$ 0
Initial Cost [Abstract]
Land	4,342
Net Improvements (Retirements) Since Acquisition	17
Carrying Amount at Which Carried [Abstract]
Land	4,332
Buildings and Improvements	27
Total	$ 4,359
Real Estate And Accumulated Depreciation Year Of Acquisition	2,006

Schedule III - Real Estate a128

Schedule III - Real Estate and Accumulated Depreciation (Reconciliation of Real Estate Investments and Accumulated Depreciation) (Parentheticals) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Balance at the Beginning of the Year		$ 4,631,128		$ 4,669,289		$ 4,726,169
Additions:
Acquisitions		182,381		0		347,510
Capital expenditures and assets placed into service		165,941		132,149		109,740
Less:
Dispositions		(442,327)		(126,471)		(474,275)
Retirements		(49,535)		(43,839)		(39,855)
Balance at the end of the year		4,487,588		4,631,128		4,669,289
Assets held for sale		(794,588)	[1]	(27,436)	[1]	0
Operating properties		3,693,000		4,603,692		4,669,289
Tax Basis of Assets, Cost for Income Tax Purposes		3,900,000		3,700,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at the beginning of the year		1,078,996		983,808		954,665
Real Estate Accumulated Depreciation Additions [Abstract]
Depreciation expense — continuing operations		159,080		160,641		150,236
Depreciation expense — discontinued operations		0		0		9,164
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Dispositions		(109,243)		(22,459)		(91,890)
Retirements		(48,217)		(42,994)		(38,367)
Balance at the end of the year		1,080,616		1,078,996		983,808
Asset held for sale		(213,581)		(11,167)		0
Real Estate Investment Property, Accumulated Depreciation		867,035		1,067,829
Aggregate carrying value		40,400
Impairment of properties held for use		27,500
Estimated Fair Value Of Impaired Property		$ 12,900
Equity Method Investment, Ownership Percentage	[2]	0.00%
Tysons Corner [Member] | Secured Debt [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Debt Instrument Maturity Date		Oct. 9, 2015
3141 Fairview Park Drive [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Equity Method Investment, Ownership Percentage		50.00%
Land and Building [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Provision for impairment on assets held for sale		$ 45,400
Aggregate carrying value		426,200
Estimated closing costs		380,800
Accumulated Depreciation, including HFS [Member]
Real Estate Accumulated Depreciation Less Dispositions [Abstract]
Real Estate Investment Property, Accumulated Depreciation		$ 867,035		$ 1,067,829		$ 983,808
[1]	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.
[2]	Ownership percentage represents the Company’s entitlement to residual distributions after payments of priority returns, where applicable.