Mack Cali Realty L P 10-K 19 Feb 15 2014 FY Annual report Financial data

Document_And_Entity_Informatio

Document And Entity Information (USD $)	12 Months Ended
	Dec. 31, 2014
Document And Entity Information [Abstract]
Entity Registrant Name	MACK CALI REALTY L P
Document Type	10-K
Amendment Flag	FALSE
Document Period End Date	31-Dec-14
Entity Central Index Key	1067063
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding	0
Entity Public Float	$0

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Rental property
Land and leasehold interests	$760,855	$750,658
Buildings and improvements	3,753,300	3,915,800
Tenant improvements	431,969	456,003
Furniture, fixtures and equipment	12,055	7,472
Gross investment in rental property	4,958,179	5,129,933
Less - accumulated depreciation and amortization	-1,414,305	-1,400,988
Net investment in rental property	3,543,874	3,728,945
Cash and cash equivalents	29,549	221,706
Investments in unconsolidated joint ventures	247,468	181,129
Unbilled rents receivable, net	123,885	136,304
Deferred charges, goodwill and other assets	204,650	218,519
Restricted cash	34,245	19,794
Accounts receivable, net of allowance for doubtful accounts of $2,584 and $2,832	8,576	8,931
Total assets	4,192,247	4,515,328
LIABILITIES AND EQUITY
Senior unsecured notes	1,267,744	1,616,575
Mortgages, loans payable and other obligations	820,910	746,191
Distributions payable	15,528	29,938
Accounts payable, accrued expenses and other liabilities	126,971	121,286
Rents received in advance and security deposits	52,146	53,730
Accrued interest payable	26,937	29,153
Total liabilities	2,310,236	2,596,873
Commitments and contingencies
Partners' Capital:
General Partner, 89,076,578 and 88,247,591 common units outstanding	1,568,098	1,585,100
Limited partners, 11,083,876 and 11,864,775 common units outstanding	258,856	278,072
Total Mack-Cali Realty, L.P. partners' capital	1,826,954	1,863,172
Noncontrolling interests in consolidated joint ventures	55,057	55,283
Total equity	1,882,011	1,918,455
Total liabilities and equity	$4,192,247	$4,515,328

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts receivable	$2,584	$2,832
General partner common units outstanding	89,076,578	88,247,591
Limited partners common units outstanding	11,083,876	11,864,775

Consolidated_Statements_Of_Ope

Consolidated Statements Of Operations (USD $)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
REVENUES
Base rents	$516,727	$540,165	$535,822
Escalations and recoveries from tenants	78,554	72,758	74,535
Construction services		15,650	13,557
Real estate services	28,638	26,935	8,606
Parking income	9,107	6,840	6,021
Other income	3,773	4,683	12,091
Total revenues	636,799	667,031	650,632
EXPENSES
Real estate taxes	90,750	85,574	86,683
Utilities	72,822	63,622	58,267
Operating services	112,621	105,278	97,005
Direct construction costs		14,945	12,647
Real estate services expenses	26,136	22,716	3,746
General and administrative	73,169	47,682	47,664
Depreciation and amortization	172,490	182,766	174,333
Impairments		110,853	9,845
Total expenses	547,988	633,436	490,190
Operating income	88,811	33,595	160,442
OTHER (EXPENSE) INCOME
Interest expense	-112,878	-123,701	-122,039
Interest and other investment income	3,615	2,903	34
Equity in earnings (loss) of unconsolidated joint ventures	-2,423	-2,327	4,089
Realized gains (losses) on disposition of rental property, net	54,848
Loss from early extinguishment of debt	-582	-156	-4,960
Total other (expense) income	-57,420	-123,281	-122,876
Income (loss) from continuing operations	31,391	-89,686	37,566
Discontinued operations:
Income from discontinued operations		11,811	21,878
Loss from early extinguishment of debt		-703
Realized gains (losses) and unrealized losses on disposition of rental property and impairments, net		59,520	-13,175
Total discontinued operations, net		70,628	8,703
Net income (loss)	31,391	-19,058	46,269
Noncontrolling interest in consolidated joint ventures	778	2,199	330
Net income (loss) available to common unitholders	$32,169	($16,859)	$46,599
Basic earnings per common unit:
Income (loss) from continuing operations	$0.32	($0.88)	$0.38
Discontinued operations		$0.71	$0.09
Net income (loss) available to common unitholders	$0.32	($0.17)	$0.47
Diluted earnings per common unit:
Income (loss) from continuing operations	$0.32	($0.88)	$0.38
Discontinued operations		$0.71	$0.09
Net income (loss) available to common unitholders	$0.32	($0.17)	$0.47
Basic weighted average units outstanding	99,999	99,785	99,922
Diluted weighted average units outstanding	100,041	99,785	99,996

Consolidated_Statement_Of_Chan

Consolidated Statement Of Changes In Equity (USD $)	General Partner Common Units [Member]	Limited Partners Common Units [Member]	General Partner Common Unitholders [Member]	Limited Partner Common Unitholders [Member]	Noncontrolling Interest In Consolidated Joint Ventures [Member]	Total
In Thousands			USD ($)	USD ($)	USD ($)	USD ($)
Balance, units at Dec. 31, 2011	87,800	12,197
Balance, value at Dec. 31, 2011			$1,832,977	$319,086	$1,937	$2,154,000
Net income (loss)			40,922	5,677	-330	46,269
Distributions			-157,946	-21,908		-179,854
Increase in noncontrolling interests					54,835	54,835
Redemption of limited partner common units for shares of general partner common units, units	55	-55
Redemption of limited partner common units for shares of general partner common units, value			1,162	-1,162
Shares issued under Dividend Reinvestment and Stock Purchase Plan, units	10
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value			259			259
Directors deferred compensation plan			490			490
Repurchase of general partner common units, units	-395
Repurchase of general partner common units, value			-11,011			-11,011
Stock compensation, units	66
Stock compensation, value			3,519			3,519
Balance, units at Dec. 31, 2012	87,536	12,142
Balance, value at Dec. 31, 2012			1,710,372	301,693	56,442	2,068,507
Net income (loss)			-14,909	-1,950	-2,199	-19,058
Distributions			-118,418	-16,193		-134,611
Increase in noncontrolling interests					1,040	1,040
Redemption of limited partner common units for shares of general partner common units, units	277	-277
Redemption of limited partner common units for shares of general partner common units, value			5,478	-5,478
Shares issued under Dividend Reinvestment and Stock Purchase Plan, units	10
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value			243			243
Directors deferred compensation plan			529			529
Stock compensation, units	425
Stock compensation, value			1,805			1,805
Balance, units at Dec. 31, 2013	88,248	11,865
Balance, value at Dec. 31, 2013			1,585,100	278,072	55,283	1,918,455
Net income (loss)			28,567	3,602	-778	31,391
Distributions			-67,011	-8,456		-75,467
Increase in noncontrolling interests					552	552
Redemption of limited partner common units for shares of general partner common units, units	781	-781
Redemption of limited partner common units for shares of general partner common units, value			14,362	-14,362
Shares issued under Dividend Reinvestment and Stock Purchase Plan, units	6
Shares issued under Dividend Reinvestment and Stock Purchase Plan, value			118			118
Directors deferred compensation plan			407			407
Stock compensation, units	42
Stock compensation, value			6,555			6,555
Balance, units at Dec. 31, 2014	89,077	11,084
Balance, value at Dec. 31, 2014			$1,568,098	$258,856	$55,057	$1,882,011

Consolidated_Statements_Of_Cas

Consolidated Statements Of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES
Net income (loss)	$31,391,000	($19,058,000)	$46,269,000
Adjustments to reconcile net income to net cash provided by Operating activities:
Depreciation and amortization, including related intangible assets	173,848,000	183,303,000	174,397,000
Depreciation and amortization on discontinued operations		8,218,000	17,765,000
Amortization of deferred stock units	407,000	529,000	490,000
Amortization of stock compensation	11,097,000	2,387,000	3,642,000
Amortization of deferred financing costs and debt discount	3,274,000	3,172,000	2,669,000
Write off of unamortized discount on senior unsecured notes	12,000	156,000	593,000
Equity in (earnings) loss of unconsolidated joint venture, net	2,423,000	2,327,000	-4,089,000
Distributions of cumulative earnings from unconsolidated joint ventures	11,213,000	8,485,000	3,990,000
Realized (gains) on disposition of rental property, net	-54,848,000	-59,520,000	13,175,000
Impairments		110,853,000	9,845,000
Changes in operating assets and liabilities:
Increase in unbilled rents receivable, net	-4,083,000	-10,105,000	-6,488,000
Increase in deferred charges, goodwill and other assets	-27,895,000	-24,623,000	-17,224,000
Decrease (increase) in accounts receivable, net	355,000	248,000	-2,065,000
Increase (decrease) in accounts payable, accrued expenses and other liabilities	15,858,000	-7,090,000	-1,816,000
(Decrease) increase in rents received in advance and security deposits	-1,583,000	-2,187,000	2,898,000
(Decrease) increase in accrued interest payable	-2,216,000	1,598,000	655,000
Net cash (used in) provided by operating activities	159,253,000	198,693,000	244,706,000
CASH FLOWS FROM INVESTING ACTIVITIES
Rental property acquisitions and related intangibles	-61,938,000	-178,294,000	-115,460,000
Rental property additions and improvements	-91,813,000	-89,869,000	-47,191,000
Development of rental property, other related costs and deposits	-25,140,000	-13,772,000	-60,354,000
Proceeds from the sale of rental property	274,839,000	332,102,000	23,429,000
Issuance of notes and mortgage receivable	-62,276,000	-16,425,000
Repayment of notes receivable	62,526,000	333,000
Investment in unconsolidated joint ventures	-67,325,000	-86,504,000	-36,051,000
Distributions in excess of cumulative earnings from unconsolidated joint ventures	35,901,000	23,907,000	1,547,000
(Increase) decrease in restricted cash	-14,451,000	-455,000	1,724,000
Net cash provided by (used in) investing activities	50,323,000	-28,977,000	-232,356,000
CASH FLOW FROM FINANCING ACTIVITIES
Borrowings from revolving credit facility	277,328,000	289,000,000	591,026,000
Repayment of revolving credit facility	-277,328,000	-289,000,000	-646,526,000
Proceeds from senior unsecured notes		268,928,000	547,926,000
Repayment of senior unsecured notes	-350,000,000	-100,000,000	-221,019,000
Proceeds from mortgages and loans payable	130,135,000	3,170,000	1,937,000
Repayment of mortgages, loans payable and other obligations	-83,808,000	-20,715,000	-52,318,000
Payment of contingent consideration	-5,228,000	-2,755,000
Payment of financing costs	-3,147,000	-5,429,000	-4,711,000
Net cash from noncontrolling interests	145,000
Repurchase of common stock			-11,011,000
Payment of distributions	-89,830,000	-149,454,000	-179,905,000
Net cash (used in) provided by financing activities	-401,733,000	-6,255,000	25,399,000
Net (decrease) increase in cash and cash equivalents	-192,157,000	163,461,000	37,749,000
Cash and cash equivalents, beginning of period	221,706,000	58,245,000	20,496,000
Cash and cash equivalents, end of period	$29,549,000	$221,706,000	$58,245,000

Organization_And_Basis_Of_Pres

Organization And Basis Of Presentation	12 Months Ended
	Dec. 31, 2014
Organization And Basis Of Presentation [Abstract]
Organization And Basis Of Presentation	1.ORGANIZATION AND BASIS OF PRESENTATION
	Organization
	Mack-Cali Realty, L.P., a Delaware limited partnership, together with its subsidiaries (collectively, the “Company” or “Operating Partnership”), was formed on May 31, 1994 to conduct the business of providing leasing, management, acquisition, development, construction and tenant-related services for its sole general partner, Mack-Cali Realty Corporation (“the Corporation” or “General Partner”).  The Company, through its operating divisions and subsidiaries, including the Mack-Cali property-owning partnerships and limited liability companies (collectively, the “Property Partnerships”) is the entity through which all of the General Partner’s operations are conducted.
	The General Partner is a fully-integrated self-administered, self-managed real estate investment trust (“REIT”). The General Partner controls the Company as its sole general partner and owned an 88.9 percent and 88.1 percent common unit interest in the Company as of December 31, 2014 and 2013, respectively.
	The General Partner’s business is the ownership of interests in and operation of the Company, and all of the General Partner’s expenses are incurred for the benefit of the Company.  The General Partner is reimbursed by the Company for all expenses it incurs relating to the ownership and operation of the Company.
	As of December 31, 2014, the Company owned or had interests in 283 properties,  consisting of 264 commercial properties, primarily class A office and office/flex properties, totaling approximately 31.0 million square feet, leased to approximately 2,000 commercial tenants, and 19 multi-family rental properties containing 5,484 residential units, plus developable land (collectively, the “Properties”).  The Properties are comprised of 249 buildings, primarily office and office/flex buildings totaling approximately 30.5 million square feet (which include 36 buildings, primarily office buildings aggregating approximately 5.6 million square feet owned by unconsolidated joint ventures in which the Company has investment interests), six industrial/warehouse buildings totaling approximately 387,400 square feet, 19 multi-family properties totaling 5,484 apartments (which include 13 properties aggregating 4,183 apartments owned by unconsolidated joint ventures in which the Company has investment interests), five parking/retail properties totaling approximately 121,500 square feet (which include two buildings aggregating 81,500 square feet owned by unconsolidated joint ventures in which the Company has investment interests), one hotel (which is owned by an unconsolidated joint venture in which the Company has an investment interest) and three parcels of land leased to others.  The Properties are located in seven states, primarily in the Northeast, plus the District of Columbia.
	BASIS OF PRESENTATION
	The accompanying consolidated financial statements include all accounts of the Company, its majority-owned and/or controlled subsidiaries and variable interest entities for which the Company has determined itself to be the primary beneficiary, if any.  See Note 2: Significant Accounting Policies – Investments in Unconsolidated Joint Ventures, for the Company’s treatment of unconsolidated joint venture interests.  Intercompany accounts and transactions have been eliminated.
	Accounting Standards Codification (“ASC”) 810, Consolidation, provides guidance on the identification of entities for which control is achieved through means other than voting rights (“variable interest entities” or “VIEs”) and the determination of which business enterprise, if any, should consolidate the VIEs. Generally, the consideration of whether an entity is a VIE applies when either: (1) the equity investors (if any) lack one or more of the essential characteristics of a controlling financial interest; (2) the equity investment at risk is insufficient to finance that entity’s activities without additional subordinated financial support; or (3) the equity investors have voting rights that are not proportionate to their economic interests and the activities of the entity involve or are conducted on behalf of an investor with a disproportionately small voting interest.  The Company consolidates VIEs in which it is considered to be the primary beneficiary.  The primary beneficiary is defined by the entity having both of the following characteristics: (1) the power to direct the activities that, when taken together, most significantly impact the variable interest entity’s performance: and (2) the obligation to absorb losses and right to receive the returns from the VIE that would be significant to the VIE.
	As of December 31, 2014 and 2013, the Company’s investments in consolidated real estate joint ventures in which the Company is deemed to be the primary beneficiary have total real estate assets of $242.9 million and $219.9 million, respectively, mortgages of $94.3 million and $81.9 million, respectively, and other liabilities of $15.7 million and $18.3 million, respectively.
	The preparation of financial statements in conformity with GAAP 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 revenues and expenses during the reporting period.  Actual results could differ from those estimates.  Certain reclassifications have been made to prior period amounts in order to conform with current period presentation.

Significant_Accounting_Policie

Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Significant Accounting Policies [Abstract]
Significant Accounting Policies	2.SIGNIFICANT ACCOUNTING POLICIES
	Rental
	PropertyRental properties are stated at cost less accumulated depreciation and amortization.  Costs directly related to the acquisition, development and construction of rental properties are capitalized.  Acquisition‑related costs are expensed as incurred.  Capitalized development and construction costs include pre-construction costs essential to the development of the property, development and construction costs, interest, property taxes, insurance, salaries and other project costs incurred during the period of development.  Capitalized development and construction salaries and related costs approximated $3.1 million,  $4.4 million and $3.8 million for the years ended December 31, 2014,  2013 and 2012, respectively.   Included in total rental property is construction, tenant improvement and development in-progress of $62.8 million and $40.8 million as of December 31, 2014 and 2013, respectively.  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.  Fully-depreciated assets are removed from the accounts.
	The Company considers a construction project as substantially completed and held available for occupancy upon the substantial completion of tenant improvements, but no later than one year from cessation of major construction activity (as distinguished from activities such as routine maintenance and cleanup).  If portions of a rental project are substantially completed and occupied by tenants, or held available for occupancy, and other portions have not yet reached that stage, the substantially completed portions are accounted for as a separate project.  The Company allocates costs incurred between the portions under construction and the portions substantially completed and held available for occupancy, primarily based on a percentage of the relative square footage of each portion, and capitalizes only those costs associated with the portion under construction.
	Properties are depreciated using the straight-line method over the estimated useful lives of the assets.  The estimated useful lives are as follows:
	Leasehold interests	Remaining lease term
	Buildings and improvements	5 to 40 years
	Tenant improvements	The shorter of the term of the
		related lease or useful life
	Furniture, fixtures and equipment	5 to 10 years
	Upon acquisition of rental property, the Company estimates the fair value of acquired tangible assets, consisting of land, building and improvements, and identified intangible assets and liabilities assumed, generally consisting of the fair value of (i) above and below market leases, (ii) in-place leases and (iii) tenant relationships.  The Company allocates the purchase price to the assets acquired and liabilities assumed based on their fair values.  The Company records goodwill or a gain on bargain purchase (if any) if the net assets acquired/liabilities assumed exceed the purchase consideration of a transaction.  In estimating the fair value of the tangible and intangible assets acquired, the Company considers information obtained about each property as a result of its due diligence and marketing and leasing activities, and utilizes various valuation methods, such as estimated cash flow projections utilizing appropriate discount and capitalization rates, estimates of replacement costs net of depreciation, and available market information.  The fair value of the tangible assets of an acquired property considers the value of the property as if it were vacant.
	Above-market and below-market lease values for acquired properties are initially recorded based on the present value (using a discount rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to each in-place lease and (ii) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the remaining initial term plus the term of any below-market fixed rate renewal options for below-market leases. The capitalized above-market lease values are amortized as a reduction of base rental revenue over the remaining terms of the respective leases, and the capitalized below-market lease values are amortized as an increase to base rental revenue over the remaining initial terms plus the terms of any below-market fixed rate renewal options of the respective leases.
	Other intangible assets acquired include amounts for in-place lease values and tenant relationship values, which are based on management’s evaluation of the specific characteristics of each tenant’s lease and the Company’s overall relationship with the respective tenant.  Factors to be considered by management in its analysis of in-place lease values include an estimate of carrying costs during hypothetical expected lease-up periods considering current market conditions, and costs to execute similar leases.  In estimating carrying costs, management includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, depending on local market conditions.  In estimating costs to execute similar leases, management considers leasing commissions, legal and other related expenses.  Characteristics considered by management in valuing tenant relationships include the nature and extent of the Company’s existing business relationships with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals.  The value of in-place leases are amortized to expense over the remaining initial terms of the respective leases.  The value of tenant relationship intangibles are amortized to expense over the anticipated life of the relationships.
	On a periodic basis, management assesses whether there are any indicators that the value of the Company’s rental properties held for use may be impaired.  In addition to identifying any specific circumstances which may affect a property or properties, management considers other criteria for determining which properties may require assessment for potential impairment.  The criteria considered by management include reviewing low leased percentages, significant near-term lease expirations, recently acquired properties, current and historical operating and/or cash flow losses, near-term mortgage debt maturities or other factors that might impact the Company’s intent and ability to hold the property.  A property’s value is impaired only if management’s estimate of the aggregate future cash flows (undiscounted and without interest charges) to be generated by the property is less than the carrying value of the property.  To the extent impairment has occurred, the loss shall be measured as the excess of the carrying amount of the property over the fair value of the property.  The Company’s estimates of aggregate future cash flows expected to be generated by each property are based on a number of assumptions.  These assumptions are generally based on management’s experience in its local real estate markets and the effects of current market conditions.  The assumptions are subject to economic and market uncertainties including, among others, demand for space, competition for tenants, changes in market rental rates, and costs to operate each property.  As these factors are difficult to predict and are subject to future events that may alter management’s assumptions, the future cash flows estimated by management in its impairment analyses may not be achieved, and actual losses or impairments may be realized in the future.
	Rental Property
	Held for Sale When assets are identified by management as held for sale, the Company discontinues depreciating the assets and estimates the sales price, net of selling costs, of such assets.  If, in management’s opinion, the estimated net sales price of the assets which have been identified as held for sale is less than the net book value of the assets, a valuation allowance is established.
	If circumstances arise that previously were considered unlikely and, as a result, the Company decides not to sell a property previously classified as held for sale, the property is reclassified as held and used.  A property that is reclassified is measured and recorded individually at the lower of (a) its carrying amount before the property was classified as held for sale, adjusted for any depreciation (amortization) expense that would have been recognized had the property been continuously classified as held and used, or (b) the fair value at the date of the subsequent decision not to sell.
	Investments in
	Unconsolidated
	Joint VenturesThe Company accounts for its investments in unconsolidated joint ventures under the equity method of accounting.  The Company applies the equity method by initially recording these investments at cost, as Investments in Unconsolidated Joint Ventures, subsequently adjusted for equity in earnings and cash contributions and distributions.  The outside basis portion of the Company’s joint ventures is amortized over the anticipated useful lives of the underlying ventures’ tangible and intangible assets acquired and liabilities assumed.  Generally, the Company would discontinue applying the equity method when the investment (and any advances) is reduced to zero and would not provide for additional losses unless the Company has guaranteed obligations of the venture or is otherwise committed to providing further financial support for the investee.  If the venture subsequently generates income, the Company only recognizes its share of such income to the extent it exceeds its share of previously unrecognized losses.
	On a periodic basis, management assesses whether there are any indicators that the value of the Company’s investments in unconsolidated joint ventures may be impaired.  An investment is impaired only if management’s estimate of the value of the investment is less than the carrying value of the investment, and such decline in value is deemed to be other than temporary.  To the extent impairment has occurred, the loss shall be measured as the excess of the carrying amount of the investment over the value of the investment.  The Company’s estimates of value for each investment (particularly in real estate joint ventures) are based on a number of assumptions that are subject to economic and market uncertainties including, among others, demand for space, competition for tenants, changes in market rental rates, and operating costs.  As these factors are difficult to predict and are subject to future events that may alter management’s assumptions, the values estimated by management in its impairment analyses may not be realized, and actual losses or impairment may be realized in the future.  See Note 4: Investments in Unconsolidated Joint Ventures.
	Cash and Cash
	EquivalentsAll highly liquid investments with a maturity of three months or less when purchased are considered to be cash equivalents.
	Deferred
	Financing CostsCosts incurred in obtaining financing are capitalized and amortized over the term of the related indebtedness. Amortization of such costs is included in interest expense and was $3,274,000, $3,172,000 and $2,669,000 for the years ended December 31, 2014, 2013 and 2012, respectively.  If a financing obligation is extinguished early, any unamortized deferred financing costs are written off and included in gains (loss) from early extinguishment of debt.  Such unamortized costs which were written off amounted to $12,000,  $156,000 and $593,000 for the years ended December 31, 2014, 2013 and 2012.
	Deferred
	Leasing CostsCosts incurred in connection with commercial leases are capitalized and amortized on a straight-line basis over the terms of the related leases and included in depreciation and amortization.  Unamortized deferred leasing costs are charged to amortization expense upon early termination of the lease. Certain employees of the Corporation are compensated for providing leasing services to the Properties.  The portion of such compensation related to commercial leases, which is capitalized and amortized, approximated  $3,840,000,  $4,223,000 and $4,354,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
	GoodwillGoodwill represents the excess of the purchase price over the fair value of net tangible and intangible assets acquired in a business combination. Goodwill is allocated to various reporting units, as applicable.  Each of the Company’s segments consists of a reporting unit.  Goodwill is not amortized. Management performs an annual impairment test for goodwill during the fourth quarter and between annual tests, management evaluates the recoverability of goodwill whenever events or changes in circumstances indicate that the carrying amount of goodwill may not be fully recoverable.  In its impairment tests of goodwill, management first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount.  If based on this assessment, management determines that the fair value of the reporting unit is not less than its carrying amount, then performing the additional two-step impairment test is unnecessary. If the carrying amount of goodwill exceeds its fair value, an impairment charge is recognized. The Company determined that its goodwill was not impaired at December 31, 2014 after management performed its impairment tests.
	Derivative
	InstrumentsThe Company measures derivative instruments, including certain derivative instruments embedded in other contracts, at fair value and records them as an asset or liability, depending on the Company’s rights or obligations under the applicable derivative contract.  For derivatives designated and qualifying as fair value hedges, the changes in the fair value of both the derivative instrument and the hedged item are recorded in earnings.  For derivatives designated as cash flow hedges, the effective portions of the derivative are reported in other comprehensive income (“OCI”) and are subsequently reclassified into earnings when the hedged item affects earnings. Changes in fair value of derivative instruments not designated as hedging and ineffective portions of hedges are recognized in earnings in the affected period.
	Revenue
	RecognitionBase rental revenue is recognized on a straight-line basis over the terms of the respective leases.  Unbilled rents receivable represents the cumulative amount by which straight-line rental revenue exceeds rents currently billed in accordance with the lease agreements.
	Above-market and below-market lease values for acquired properties are initially recorded based on the present value (using a discount rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to each in-place lease and (ii) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the remaining initial term plus the term of any below-market fixed-rate renewal options for below-market leases.  The capitalized above-market lease values for acquired properties are amortized as a reduction of base rental revenue over the remaining terms of the respective leases, and the capitalized below-market lease values are amortized as an increase to base rental revenue over the remaining initial terms plus the terms of any below-market fixed-rate renewal options of the respective leases.
	Escalations and recoveries from tenants are received from tenants for certain costs as provided in the lease agreements.  These costs generally include real estate taxes, utilities, insurance, common area maintenance and other recoverable costs.  See Note 16: Tenant Leases.
	Construction services revenue includes fees earned and reimbursements received by the Company for providing construction management and general contractor services to clients.  Construction services revenue is recognized on the percentage of completion method.  Using this method, profits are recorded on the basis of our estimates of the overall profit and percentage of completion of individual contracts.  A portion of the estimated profits is accrued based upon estimates of the percentage of completion of the construction contract.  This revenue recognition method involves inherent risks relating to profit and cost estimates.
	Real estate services revenue includes property management, development and leasing commission fees and other services, and payroll and related costs reimbursed from clients.  Fee income derived from the Company’s unconsolidated joint ventures (which are capitalized by such ventures) are recognized to the extent attributable to the unaffiliated ownership interests.
	Parking income includes income from parking spaces leased to tenants and others.
	Other income includes income from tenants for additional services arranged for by the Company and income from tenants for early lease terminations.
	Allowance for
	Doubtful AccountsManagement performs a detailed review of amounts due from tenants to determine if an allowance for doubtful accounts is required based on factors affecting the collectability of the accounts receivable balances.  The factors considered by management in determining which individual tenant receivable balances, or aggregate receivable balances, require a collectability allowance include the age of the receivable, the tenant’s payment history, the nature of the charges, any communications regarding the charges and other related information. Management’s estimate of the allowance for doubtful accounts requires management to exercise significant judgment about the timing, frequency and severity of collection losses, which affects the allowance and net income.
	Income and
	Other TaxesThe Company is a partnership, and, as a result, all income and losses of the partnership are allocated to the partners for inclusion in their respective tax returns.  Accordingly, no provision or benefit for income taxes has been made in the accompanying financial statements.
	As of December 31, 2014, the estimated net basis of the rental property for federal income tax purposes was lower than the net assets as reported in the Company’s financial statements by approximately $366,131,000. The Company’s taxable income for the year ended December 31, 2014 was estimated to be approximately $73,546,000 and for the years ended December 31, 2013 and 2012 was approximately $114,522,000 and $145,928,000, respectively. The differences between book income and taxable income primarily result from differences in depreciation expenses, the recording of rental income, differences in the deductibility of certain expenses for tax purposes, differences in revenue recognition and the rules for tax purposes of a property exchange.
	Certain of the Company’s corporate subsidiaries are taxable REIT subsidiaries (each a “TRS”).  In general, a TRS may perform additional services for tenants of the Company and generally may engage in any real estate or non-real estate related business (except for the operation or management of health care facilities or lodging facilities or the providing to any person, under a franchise, license or otherwise, rights to any brand name under which any lodging facility or health care facility is operated).  A TRS is subject to corporate federal income tax.  The Company has conducted business through its TRS entities for certain property management, development, construction and other related services, as well as to hold a joint venture interest in a hotel and other matters.
	As of December 31, 2014, the Company had a deferred tax asset related to its TRS activity with a balance of approximately  $14.4 million which has been fully reserved for through a valuation allowance.  If the Corporation fails to qualify as a REIT in any taxable year, the Corporation will be subject to federal income tax (including any applicable alternative minimum tax) on its taxable income at regular corporate tax rates.  The Corporation is subject to certain state and local taxes.
	Pursuant to the amended provisions related to uncertain tax provisions of ASC 740, Income Taxes, the Company recognized no material adjustments regarding its tax accounting treatment.  The Company expects to recognize interest and penalties related to uncertain tax positions, if any, as income tax expense, which is included in general and administrative expense.
	In the normal course of business, the Company or one of its subsidiaries is subject to examination by federal, state and local jurisdictions in which it operates, where applicable.  As of December 31, 2014, the tax years that remain subject to examination by the major tax jurisdictions under the statute of limitations are generally from the year 2010 forward.
	Earnings
	Per UnitThe Company presents both basic and diluted earnings per unit (“EPU”).  Basic EPU excludes dilution and is computed by dividing net income available to common unitholders by the weighted average number of units outstanding for the period.  Diluted EPU reflects the potential dilution that could occur if securities or other contracts to issue common units were exercised or converted into common units, where such exercise or conversion would result in a lower EPU amount from continuing operations amount.  Units whose issuance is contingent upon the satisfaction of certain conditions shall be considered outstanding and included in the computation of diluted EPU as follows (i) if all necessary conditions have been satisfied by the end of the period (the events have occurred), those units shall be included as of the beginning of the period in which the conditions were satisfied (or as of the date of the grant, if later) or (ii) if all necessary conditions have not been satisfied by the end of the period, the number of contingently issuable units included in diluted EPU shall be based on the number of units, if any, that would be issuable if the end of the reporting period were the end of the contingency period (for example, the number of units that would be issuable based on current period earnings or period-end market price) and if the result would be dilutive. Those contingently issuable units shall be included in the denominator of diluted EPU as of the beginning of the period (or as of the date of the grant, if later).
	Distributions
	PayableThe distributions payable at December 31, 2014 represents distributions payable to common unitholders (99,950,528 units) for all such holders of record as of January 6, 2015 with respect to the fourth quarter 2014. The fourth quarter 2014 common unit distributions of $0.15 per common unit were approved by the Corporation’s Board of Directors on December 9, 2014.  The common unit distributions payable were paid on January 14, 2015.
	The distributions payable at December 31, 2013 represents distributions payable to common unitholders (99,792,777 units), for all such holders of record as of January 6, 2014 with respect to the fourth quarter 2013.  The fourth quarter 2013 common unit distributions of $0.30 per common unit were approved by the Corporation’s Board of Directors on December 10, 2013.  The common unit distributions payable were paid on January 15, 2014.
	The Company has determined that the $0.90 distributions per common unit paid during the year ended December 31, 2014 represented approximately 77 percent ordinary income and approximately 23 percent return of capital to its unitholders; the $1.50 distributions per common unit paid during the year ended December 31, 2013 represented approximately 53 percent ordinary income, approximately 33 percent return of capital and approximately 14 percent capital gain to its unitholders; and the $1.80 distributions per common unit paid during the year ended December 31, 2012 represented approximately 75 percent ordinary income and approximately 25 percent return of capital to its unitholders.
	Costs Incurred
	For Stock
	IssuancesCosts incurred in connection with the Corporation’s stock issuances are reflected as a reduction of General Partner’s capital.
	Stock
	CompensationThe Company accounts for stock compensation in accordance with the provisions of ASC 718, Compensation-Stock Compensation. These provisions require that the estimated fair value of restricted stock (“Restricted Stock Awards”), total stockholder return (“TSR”) based performance shares and stock options at the grant date be amortized ratably into expense over the appropriate vesting period.  The Company recorded stock compensation expense of $8,139,000,  $2,387,000 and $3,642,000 for the years ended December 31, 2014, 2013 and 2012, respectively.  The amount for 2014 included $5,824,000 related to the departure of executive officers.  See Note 15: Commitments and Contingencies – Departure of Executive Officers.
	Other
	Comprehensive
	IncomeOther comprehensive income (loss) includes items that are recorded in equity, such as unrealized holding gains or losses on marketable securities available for sale.  There was no difference in other comprehensive income to net income for the years ended December 31, 2014, 2013 and 2012, and no accumulated other comprehensive income as of December 31, 2014 and 2013.
	Fair Value
	HierarchyThe standard Fair Value Measurements specifies a hierarchy of valuation techniques based upon whether the inputs to those valuation techniques reflect assumptions other market participants would use based upon market data obtained from independent sources (observable inputs). The following summarizes the fair value hierarchy:
		·	Level 1: Quoted prices in active markets that are unadjusted and accessible at the measurement date for identical, unrestricted assets or liabilities;
	·	Level 2: Quoted prices for identical assets and liabilities in markets that are inactive, quoted prices for similar assets and liabilities in active markets or financial instruments for which significant inputs are observable, either directly or indirectly, such as interest rates and yield curves that are observable at commonly quoted intervals and
	·	Level 3: Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable.
In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy.  In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined 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.
Discontinued
Operations In April 2014, the FASB issued guidance related to the reporting of discontinued operation and disclosures of disposals of components of an entity.  This guidance defines a discontinued operation as a component or group of components disposed or classified as held for sale and represents a strategic shift that has (or will have) a major effect on an entity’s operations and final result; the guidance states that a strategic shift could include a disposal of a major geographical area of operations, a major line of business, a major equity method investment or other major parts of an entity.  The guidance also provides for additional disclosure requirements in connection with both discontinued operations and other dispositions not qualifying as discontinued operations.  The guidance will be effective for all companies for annual and interim periods beginning on or after December 15, 2014.  The guidance applies prospectively to new disposals and new classifications of disposal groups as held for sale after the effective date.  All entities may early adopt the guidance for new disposals (or new classifications as held for sale) that have not been reported in financial statements previously issued or available for issuance.    The Company has elected to early adopt this standard effective with the interim period beginning January 1, 2014.    Prior to January 1, 2014, properties identified as held for sale and/or disposed of were presented in discontinued operations for all periods presented.  See Note 7: Discontinued Operations.
Out of Period
AdjustmentsDuring the year ended December 31, 2014, the Company identified and recorded out-of-period adjustments to reduce base rental revenue by a total of $686,000 to correct errors in the cumulative calculations of unbilled rents receivable attributable to two leases from prior years.  The Company has determined that the adjustments were not material to the year ended December 31, 2014 or the prior periods.
Impact Of
Recently-Issued
Accounting
StandardsIn May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09 Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”).  ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services.  In adopting ASU 2014-09, companies may use either a full retrospective or a modified retrospective approach.  Additionally, this guidance requires improved disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers.  ASU 2014-09 is effective for the first interim period within annual reporting periods beginning after December 15, 2016, and early adoption is not permitted.  The Company is currently in the process of evaluating the impact the adoption of ASU 2014-09 will have on the Company’s financial position or results of operations.
In August 2014, the FASB issued ASU 2014-15, which requires management to evaluate whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern, and to provide certain disclosures when it is probable that the entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued.  ASU 2014-15 is effective for the annual period ended December 31, 2016 and for annual periods and interim periods thereafter with early adoption permitted.  The adoption of ASU 2014-15 is not expected to materially impact the Company’s consolidated financial statements.

Real_Estate_Transactions

Real Estate Transactions	12 Months Ended
	Dec. 31, 2014
Real Estate Transactions [Abstract]
Real Estate Transactions	3.REAL ESTATE TRANSACTIONS
	Acquisitions
	2014
	On April 10, 2014, the Company acquired Andover Place, a 220-unit multi-family rental property located in Andover, Massachusetts, for approximately $37.7 million, which was funded primarily through borrowing under the Company’s unsecured revolving credit facility.
	The purchase price was allocated to the net assets acquired, as follows (in thousands):
			Andover
			Place
	Land	$	8,535
	Buildings and improvements		27,609
	Furniture, fixtures and equipment		459
	In-place lease values (1)		1,118
			37,721
	Less: Below market lease values (1)		-25
	Net cash paid at acquisition	$	37,696
	(1) In-place lease values and below market lease values will be amortized over one year or less.
	On August 15, 2014, the Company acquired the equity interests of its joint venture partner in Overlook Ridge, L.L.C, Overlook Ridge JV, L.L.C. and Overlook Ridge JV 2C/3B, L.L.C. for $16.6 million, which was funded primarily through borrowing under the Company’s unsecured revolving credit facility.  As a result, the Company increased its ownership to 100 percent of the developable land and now consolidates these entities which were previously accounted for through unconsolidated joint ventures (collectively, the “Consolidated Land”); and acquired an additional 25 percent, for a total of 50 percent of its subordinated, unconsolidated interests in two operating multi-family properties owned by those entities.  See Note 4: Investments in Unconsolidated Joint Ventures.  In conjunction with the Company’s acquisition of the Consolidated Land, the Company assumed loans with a total principal balance of $23.0 million, which bear interest in the range of LIBOR plus 2.50 to 3.50 percent.  See Note 10: Mortgages, Loans Payable and Other Obligations.
	On December 2, 2014, the Company acquired developable land in Conshohocken, Pennsylvania, for approximately $15.3 million, which was funded using available cash.
	For the year ended December 31, 2014, included in general and administrative expense was an aggregate of approximately $2.1 million in transactions costs related to the Company’s property and joint venture acquisitions.
	Excluded from the cash flow statement for the year ended December 31, 2014 was $44.4 million of acquisition and other investment fundings (of which $40.1 million related to the acquisition of 50 percent tenants in common interests in the Curtis Center property.  See Unconsolidated Joint Venture Transactions in Note 4: Investments in Unconsolidated Joint Ventures), which were handled through a qualified intermediary using proceeds from prior sales structured for tax purposes as Section 1031 transactions.
	2013
	The following multi-family rental properties were acquired during the year ended December 31, 2013 (dollars in thousands):
	Acquisition			# of	# of			Acquisition
	Date	Property	Location	Properties	Apartment Units			Cost
	1/18/13	Alterra at Overlook Ridge 1A	Revere, Massachusetts	1	310		$	61,250	(a)
	4/4/13	Alterra at Overlook Ridge 1B	Revere, Massachusetts	1	412			87,950	(a)
	11/20/13	Park Square	Rahway, New Jersey	1	159			46,376	(b)
	12/19/13	Richmond  Ct / Riverwatch Commons	New Brunswick, New Jersey	2	200			40,983	(c)
	Total Acquisitions			5	1,081		$	236,559
	(a)The acquisition cost was funded primarily through borrowings under the Company’s unsecured revolving credit facility.
	(b)The acquisition cost consisted of $43,421,000 in cash consideration and future purchase price earn out payment obligations, subsequent to conditions related to a real estate tax appeal, recorded at fair value of $2,955,000 at closing.  $42,613,355 of the cash consideration was funded from funds held by a qualified intermediary, which were proceeds from the Company’s prior property sales.  The remaining cash consideration was funded primarily from available cash on hand.  $2,550,000 of the earn-out obligation amount was paid in January 2014, with the remaining balance of $405,000 still potentially payable in the future.
	(c)$12,701,925 of the acquisition cost was funded from funds held by a qualified intermediary, which were proceeds from the Company’s prior property sales.  The remaining acquisition cost was funded primarily from available cash on hand.
	The purchase prices were allocated to the net assets acquired during the year ended December 31, 2013, as follows (in thousands):
			Alterra			Alterra
			at Overlook			at Overlook			Park			Richmond			Riverwatch		Total
			Ridge 1A			Ridge 1B			Square			Court			Commons		Acquisitions
	Land	$	9,042		$	12,055		$	4,000		$	2,992		$	4,169	$	32,258
	Buildings and improvements		50,671			71,409			40,670			13,534			18,974		195,258
	Furniture, fixtures and equipment		801			1,474			610			177			228		3,290
	Above market leases (1)		-			-			24			-			-		24
	In-place lease values (1)		931			3,148			1,249			356			638		6,322
			61,445			88,086			46,553			17,059			24,009		237,152
	Less: Below market lease values (1)		195			136			177			36			49		593
			195			136			177			36			49		593
	Net cash paid at acquisition	$	61,250		$	87,950		$	46,376		$	17,023		$	23,960	$	236,559
	(1)In-place lease values and above/below market lease values will be amortized over one year or less.
	For the year ended December 31, 2013, included in general and administrative expense was an aggregate of approximately $642,000 in transaction costs related to the property acquisitions.
	Consolidation
	On August 22, 2013, the Company contributed an additional $4.9 million and the operating agreement of Eastchester was modified which increased the Company’s effective ownership to 76.25 percent, with the remaining 23.75 percent owned by HVLH.  The agreement also provided the Company with control of all major decisions.  Accordingly, effective August 22, 2013, the Company consolidated Eastchester under the provisions of ASC 810, Consolidation.  As the carrying value approximated the fair value of the net assets acquired, there was no holding period gain or loss recognized on this transaction.
	The Company had previously acquired a 26.25 percent interest in a to-be-built, 108-unit multi-family rental property located in Eastchester, New York (the “Eastchester Project”) for approximately $2.1 million.  The remaining interests in the development project-owning entity, 150 Main Street, L.L.C. (“Eastchester”) was owned 26.25 percent by JMP Eastchester, L.L.C. and 47.5 percent by Hudson Valley Land Holdings, L.L.C. (“HVLH”).  The Eastchester Project began construction in late 2013.  Estimated total development costs of $50 million (of which $13.9 million have been incurred through December 31, 2014) are expected to be funded with a $28.8 million construction loan and the balance of $21.2 million from member’s capital, of which the Company’s share is $20.9 million.
	The following table summarizes the net assets recorded upon consolidation (in thousands):
	Land		$	5,585
	Construction in progress			3,387
				8,972
	Cash and cash equivalents			79
	Other assets			47
	Accounts payable			-325
				-199
	Noncontrolling interest recorded upon consolidation			-1,252
	Net assets recorded upon consolidation		$	7,521
	Properties Commencing Initial Operations
	The following properties commenced initial operations during the year ended December 31, 2013 (dollars in thousands):
							Garage			Development				Development
					# of	Rentable	Parking			Costs Incurred				Costs Per
	Date	Property/Address	Location	Type	Bldgs.	Square Feet	Spaces			by Company				Square Foot
6/5/13	14 Sylvan Way	Parsippany, New Jersey	Office	1	203,506	-		$	51,611	(a)		$	254
8/1/13	Port Imperial South 4/5	Weehawken, New Jersey	Parking/Retail	1	16,736	850			50,656	(b)			N/A
Totals				2	220,242	850		$	102,267
(a)Development costs included approximately $13.0 million in land costs and $4.3 million in leasing costs.  Amounts are as of December 31, 2013.
(b)Development costs included approximately $13.1 million in land costs.  Amounts are as of December 31, 2013.
Sales
2014
The Company sold the following office properties during the year ended December 31, 2014 (dollars in thousands):
				Rentable			Net			Net
Sale			# of	Square			Sales			Book			Realized
Date	Property/Address	Location	Bldgs.	Feet			Proceeds			Value			Gain
4/23/14	22 Sylvan Way	Parsippany, New Jersey	1	249,409		$	94,897		$	60,244		$	34,653
6/23/14	30 Knightsbridge Road (a)	Piscataway, New Jersey	4	680,350			54,641			52,361			2,280
6/23/14	470 Chestnut Ridge Road (a) (b)	Woodcliff Lake, New Jersey	1	52,500			7,195			7,109			86
6/23/14	530 Chestnut Ridge Road (a) (b)	Woodcliff Lake, New Jersey	1	57,204			6,299			6,235			64
6/27/14	400 Rella Boulevard	Suffern, New York	1	180,000			27,539			10,938			16,601
6/30/14	412 Mount Kemble Avenue (a)	Morris Township, New Jersey	1	475,100			44,751			43,851			900
7/29/14	17-17 Route 208 North (a) (b)	Fair Lawn, New Jersey	1	143,000			11,835			11,731			104
8/20/14	555, 565, 570 Taxter Road (a)	Elmsford, New York	3	416,108			41,057			41,057			-
8/20/14	200, 220 White Plains Road (a)	Tarrytown, New York	2	178,000			12,619			12,619			-
8/20/14	1266 East Main Street (a) (b)	Stamford, Connecticut	1	179,260			18,406			18,246			160
Totals			16	2,610,931		$	319,239		$	264,391		$	54,848
(a)The Company completed the sale of these properties for approximately $221 million comprised of: $192.5 million in cash from a combination of affiliates of Keystone Property Group (“Keystone Entities”) senior and pari-passu equity and mortgage financing; Company subordinated equity interests in each of the properties sold with capital accounts aggregating $21.2 million and Company pari-passu equity interests in five of the properties sold aggregating $7.3 million.  Net sale proceeds from the sale aggregated $196.8 million which was comprised of the $221 million gross sales price less the subordinated equity interests of $21.2 million and $3 million in closing costs.  The purchasers of these properties are unconsolidated joint ventures formed between the Company and the Keystone Entities.  The senior and pari-passu equity will receive a 15 percent internal rate of return (“IRR”) after which the subordinated equity will receive a 10 percent IRR and then all distributable cash flow will be split equally between the Keystone Entities and the Company.  See Note 4: Investments in Unconsolidated Joint Ventures.  In connection with certain of these partial sale transactions, because the buyer received a preferential return on certain of the ventures for which the Company received subordinated equity interests, the Company only recognized profit to the extent that they received net proceeds in excess of their entire carrying value of the properties, effectively reflecting their retained subordinated equity interest at zero.
(b)The Company recorded an impairment charge of $20.8 million on these properties at December 31, 2013 as it estimated that the carrying value of the properties may not be recoverable over their anticipated holding periods.
On January 1, 2014, the Company early adopted the new discontinued operations accounting standard and as the properties sold during the year ended December 31, 2014 did not represent a strategic shift (as the Company is not entirely exiting markets or property types), they have not been reflected as part of discontinued operations.
The following table summarizes income from the properties sold during the year ended December 31, 2014 for the years ended December 31, 2014, 2013 and 2012: (dollars in thousands)
		Year Ended December 31,
			2014			2013			2012
Total revenues		$	28,823		$	55,677		$	54,753
Operating and other expenses			-17,248			-27,993			-25,142
Depreciation and amortization			-6,371			-15,061			-14,522
Interest income			4			-			-615
Income from properties sold		$	5,208		$	12,623		$	14,474
Impairments			-			-20,761			-
Realized gains (losses) on sales, net			54,848			-			-
Total income (loss) from properties sold		$	60,056		$	-8,138		$	14,474
2013
The Company sold the following office properties during the year ended December 31, 2013, which were classified as discontinued operations – See Note 7: Discontinued Operations (dollars in thousands):
				Rentable			Net			Net
Sale			# of	Square			Sales			Book			Realized
Date	Property/Address	Location	Bldgs.	Feet			Proceeds			Value			Gain (loss)
4/10/13	19 Skyline Drive (a)	Hawthorne, New York	1	248,400		$	16,131		$	16,005		$	126
4/26/13	55 Corporate Drive	Bridgewater, New Jersey	1	204,057			70,967			51,308			19,659
5/2/13	200 Riser Road	Little Ferry, New Jersey	1	286,628			31,775			14,852			16,923
5/13/13	777 Passaic Avenue	Clifton, New Jersey	1	75,000			5,640			3,713			1,927
5/30/13	16 and 18 Sentry Parkway West (b)	Blue Bell, Pennsylvania	2	188,103			19,041			19,721			-680
5/31/13	51 Imclone Drive (c)	Branchburg, New Jersey	1	63,213			6,101			5,278			823
6/28/13	40 Richards Avenue	Norwalk, Connecticut	1	145,487			15,858			17,027			-1,169
7/10/13	106 Allen Road	Bernards Township, New Jersey	1	132,010			17,677			15,081			2,596
8/27/13	Pennsylvania office portfolio (d) (e)	Suburban Philadelphia, Pennsylvania	15	1,663,511			207,425			164,259			43,166
Totals			24	3,006,409		$	390,615	(f)	$	307,244		$	83,371	(g)
	(a)		The Company recognized a valuation allowance of $7.1 million on this property identified as held for sale at December 31, 2012.  In connection with the sale, the Company provided an interest-free note receivable to the buyer of $5 million (with a net present value of $3.7 million at closing) which matures in 2023 and requires monthly payments of principal.  See Note 5: Deferred charges, goodwill and other assets.
	(b)		The Company recorded an $8.4 million impairment charge on these properties at December 31, 2012.  The Company has retained a subordinated interest in these properties.
	(c)		The property was encumbered by a mortgage loan which was satisfied by the Company at the time of the sale.  The Company incurred $0.7 million in costs for the debt satisfaction, which was included in discontinued operations:  loss from early extinguishment of debt for the year ended December 31, 2013.
	(d)		In order to reduce the carrying value of five of the properties to their estimated fair market values, the Company recorded impairment charges of $23,851,000 at June 30, 2013.  The fair value used in the impairment charges was based on the purchase and sale agreement for the properties ultimately sold.
	(e)		The Company completed the sale of this office portfolio and three developable land parcels for approximately $233 million: $201 million in cash ($55.3 million of which was held by a qualified intermediary until such funds were used in acquisitions), a $10 million mortgage on one of the properties ($8 million of which was funded at closing) and subordinated equity interests in each of the properties being sold with capital accounts aggregating $22 million.  Net sale proceeds from the sale aggregated $207 million which was comprised of the $233 million gross sales price less the subordinated equity interests of $22 million and $4 million in closing costs. The purchasers of the Pennsylvania office portfolio are joint ventures formed between the Company and affiliates of the Keystone Property Group (the “Keystone Affiliates”).  The mortgage loan has a term of two years with a one year extension option and bears interest at LIBOR plus six percent.  The Company's equity interests in the joint ventures will be subordinated to Keystone Affiliates receiving a 15 percent internal rate of return (“IRR”) after which the Company will receive a ten percent IRR on its subordinated equity and then all profit will be split equally.  In connection with these partial sale transactions, because the buyer receives a preferential return, the Company only recognized profit to the extent that they received net proceeds in excess of their entire carrying value of the properties, effectively reflecting their retained subordinate equity interest at zero.  As part of the transaction, the Company has rights to own, after zoning-approval-subdivision, land at the 150 Monument Road property located in Bala Cynwyd, Pennsylvania, for a contemplated multi-family residential development.
	(f)		This amount excludes approximately $535,000 of net closing prorations and related adjustments received from sellers at closing.
	(g)		This amount, net of impairment charges recorded in 2013 of $23,851,000 on certain of the properties prior to their sale (per Note [d] above), comprises the $59,520,000 of realized gains (losses) and unrealized losses on disposition of rental property and impairments, net, for the year ended December 31, 2013.  See Note 7: Discontinued Operations.
Impairments on Properties Held and Used
For the year ended December 31, 2013, the Company recorded impairment charges of $110.9 million on 18 office properties.  Nine of the 18 properties located in Roseland, Parsippany, Warren and Lyndhurst, New Jersey, aggregating approximately 1.3 million square feet, are collateral for mortgage loans maturing on August 11, 2014 and May 11, 2016, with principal balances totaling $160 million as of December 31, 2013.  Seven of the 18 properties located in Fair Lawn, New Jersey, Woodcliff Lake, New Jersey, Stamford, Connecticut and Elmsford, New York, aggregating 646,000 square feet, were subsequently sold in 2014 (six of which are part of the Keystone Entities transaction described above).  Two of the 18 properties, located in Morris Plains and Upper Saddle River, New Jersey, aggregating approximately 550,000 square feet, are being considered for repositioning from office properties into multi-family rental properties.  The Company estimated that the carrying value of the 18 properties may not be recoverable over their anticipated holding periods.  The impairments in 2013 resulted primarily from the recent decline in leasing activity and market rents of the properties identified.
The Company’s estimated fair values for the year ended December 31, 2013 were derived utilizing a discounted cash flow (“DCF”) model including all estimated cash inflows and outflows over a specified holding period.  These cash flows were comprised of inputs which included contractual revenues and forecasted revenues and expenses based upon market conditions and expectations for growth.  The capitalization rate of 8.5 percent for the year ended December 31, 2013 and discount rates ranging from 10 percent to 15 percent for the year ended December 31, 2013 utilized in DCF were based upon the risk profile of the properties’ cash flows and observable rates that the Company believes to be within a reasonable range of current market rates for each respective property.  Based on these inputs the Company determined that its valuation of these investments was classified within Level 3 of the fair value hierarchy, as provided by ASC 820, Fair Value Measurements and Disclosures.

Investments_In_Unconsolidated_

Investments In Unconsolidated Joint Ventures	12 Months Ended
	Dec. 31, 2014
Investments In Unconsolidated Joint Ventures [Abstract]
Investments In Unconsolidated Joint Ventures	4.INVESTMENTS IN UNCONSOLIDATED JOINT VENTURES
	As of December 31, 2014, the Company had an aggregate investment of approximately $247.5 million in its equity method joint ventures.  The Company formed these ventures with unaffiliated third parties, or acquired interests in them, to develop or manage primarily office and multi-family rental properties, or to acquire land in anticipation of possible development of office and multi-family rental properties.  As of December 31, 2014, the unconsolidated joint ventures owned: 36 office properties aggregating approximately 5.6 million square feet, 13 multi-family properties totaling 4,183 apartments, two retail properties aggregating approximately 81,500 square feet, a  350-room hotel, development projects for up to approximately 1,731 apartments; and interests and/or rights to developable land parcels able to accommodate up to 2,853 apartments and 1.4 million square feet of office space.  The Company’s unconsolidated interests range from 7.5 percent to 85 percent subject to specified priority allocations in certain of the joint ventures.
	On October 23, 2012, the Company acquired the real estate development and management businesses (the “Roseland Business”) of Roseland Partners, L.L.C. (“Roseland Partners”), a premier multi-family rental community developer and manager, and the Roseland Partners’ interests (the “Roseland Transaction”), principally through unconsolidated joint venture interests in various entities which, directly or indirectly, own or have rights with respect to various residential and/or commercial properties or vacant land (collectively, the “Roseland Assets”).  The locations of the properties extend from New Jersey to Massachusetts, with the majority of the properties located in New Jersey.  Certain of the entities which own the Roseland Assets are controlled by the Company upon acquisition and are therefore consolidated. However, many of the entities are not controlled by the Company and, therefore, are accounted for under the equity method as investments in unconsolidated joint ventures.
	The amounts reflected in the following tables (except for the Company’s share of equity in earnings) are based on the historical financial information of the individual joint ventures.  The Company does not record losses of the joint ventures in excess of its investment balances unless the Company is liable for the obligations of the joint venture or is otherwise committed to provide financial support to the joint venture.  The outside basis portion of the Company’s investments in joint ventures is amortized over the anticipated useful lives of the underlying ventures’ tangible and intangible assets acquired and liabilities assumed.  Unless otherwise noted below, the debt of the Company’s unconsolidated joint ventures generally is non-recourse to the Company, except for customary exceptions pertaining to such matters as intentional misuse of funds, environmental conditions, and material misrepresentations.
	The Company has agreed to guarantee repayment of a portion of the debt of its unconsolidated joint ventures.  As of December 31, 2014, such debt had a total facility amount of $477 million of which the Company agreed to guarantee up to $93.5 million.  As of December 31, 2014, the outstanding balance of such debt totaled $238 million of which $62.6 million was guaranteed by the Company.  The Company also posted a $4.1 million letter of credit in support of the South Pier at Harborside joint venture, half of which is indemnified by Hyatt Corporation, the Company’s joint venture partner.  The Company performed management, leasing, development and other services for the properties owned by the unconsolidated joint ventures and recognized $6.2 million and $5.8 million for such services in the years ended December 31, 2014 and 2013, respectively.  The Company had $1.0 million and $523,000 in accounts receivable due from its unconsolidated joint ventures as of December 31, 2014 and 2013.
	Included in the Company’s investments in unconsolidated joint ventures as of December 31, 2014 are nine unconsolidated development joint ventures, which are VIEs for which the Company is not the primary beneficiary. These joint ventures are primarily established to develop real estate property for long-term investment and were deemed VIEs primarily based on the fact that the equity investment at risk was not sufficient to permit the entities to finance their activities without additional financial support.  The initial equity contributed to these entities 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 these VIEs based on the fact that the Company has shared control of these entities along with the entity’s partners and therefore does not have controlling financial interests in these VIEs.  The Company’s aggregate investment in these VIEs was approximately $113.6 million as of December 31, 2014.  The Company’s maximum exposure to loss as a result of its involvement with these VIEs is estimated to be approximately $230.5 million, which includes the Company’s current investment and estimated future funding commitments/guarantees of approximately $116.9 million.  The Company has not provided financial support to these VIEs that it was not previously contractually required to provide.  In general, future costs of development not financed through third parties will be funded with capital contributions from the Company and its outside partners in accordance with their respective ownership percentages.
	The following is a summary of the Company's unconsolidated joint ventures as of December 31, 2014 and 2013: (dollars in thousands)
													Property Debt
		Number of		Company's				Carrying Amount					As of December 31, 2014
		Apartment Units		Effective				As of December 31,						Maturity	Interest
	Entity / Property Name	or Square Feet (sf)		Ownership % (a)				2014			2013		Balance	Date	Rate
	Multi-family
	Marbella RoseGarden, L.L.C./ Marbella  (b)	412	units	24.27	%		$	15,779		$	15,797	$	95,000	5/1/18	4.99	%
	RoseGarden Monaco Holdings, L.L.C./ Monaco   (b)	523	units	15.00	%			2,161			3,201		165,000	2/1/21	4.19	%
	Rosewood Lafayette Holdings, L.L.C./ Highlands at Morristown Station  (b)	217	units	25.00	%			62			857		38,665	7/1/15	4.00	%
	PruRose Port Imperial South 15, LLC /RiversEdge at Port Imperial (b)	236	units	50.00	%			-			-		57,500	9/1/20	4.32	%
	Rosewood Morristown, L.L.C. / Metropolitan at 40 Park  (c) (d)	130	units	12.50	%			6,029			6,455		46,217	(e)	(e)
	Overlook Ridge JV, L.L.C./ Quarrystone at Overlook Ridge  (b) (f)	251	units	50.00	%			-			-		69,501	(g)	(g)
	Overlook Ridge JV 2C/3B, L.L.C./The Chase at Overlook Ridge  (b) (f)	371	units	50.00	%			2,524			-		49,824	12/26/15	L+2.50	%	(h)
	PruRose Riverwalk G, L.L.C./ RiverTrace at Port Imperial   (b)	316	units	25.00	%			955			3,117		79,594	7/15/21	6.00	%	(i)
	Elmajo Urban Renewal Associates, LLC / Lincoln Harbor (Bldg A&C) (b)	355	units	7.50	%			-			203		81,264	6/27/16	L+2.10	%	(j)
	Crystal House Apartments Investors LLC / Crystal House  (k)	828	units	25.00	%			27,051			26,838		165,000	4/1/20	3.17	%
	Portside Master Company, L.L.C./ Portside at Pier One - Bldg 7  (b)	176	units	38.25	%			1,747			3,207		37,093	12/4/15	L+2.50	%	(l)
	PruRose Port Imperial South 13, LLC / RiverParc at Port Imperial  (b)	280	units	20.00	%			1,087			2,206		49,084	6/27/16	L+2.15	%	(m)
	Roseland/Port Imperial Partners, L.P./ Riverwalk C  (b) (n)	363	units	20.00	%			1,800			2,068		-	-	-
	RoseGarden Marbella South, L.L.C./ Marbella II	311	units	24.27	%			11,282			7,567		31,564	3/30/17	L+2.25	%	(o)
	Estuary Urban Renewal Unit B, LLC / Lincoln Harbor (Bldg B)  (b)	227	units	7.50	%			-			24		40,366	1/25/17	L+2.10	%	(p)
	Riverpark at Harrison I, L.L.C./ Riverpark at Harrison	141	units	36.00	%			4,744			3,655		21,298	6/27/16	L+2.35	%	(q)
	Capitol Place Mezz LLC / Station Townhouses	377	units	50.00	%			49,327			46,628		73,971	7/1/33	4.82	%	(r)
	Harborside Unit A Urban Renewal, L.L.C. / URL Harborside  (ab)	763	units	85.00	%			34,954			-		-	8/1/29	5.197	%	(aa)
	RoseGarden Monaco, L.L.C./ San Remo Land	300	potential units	41.67	%			1,283			1,224		-	-	-
	Grand Jersey Waterfront URA, L.L.C./ Liberty Landing	1,000	potential units	50.00	%			337			337		-	-	-
	Office
	Red Bank Corporate Plaza, L.L.C./ Red Bank	92,878	sf	50.00	%			3,963			4,046		15,868	5/17/16	L+3.00	%	(s)
	12 Vreeland Associates, L.L.C./ 12 Vreeland Road	139,750	sf	50.00	%			5,620			5,514		14,002	7/1/23	2.87	%
	BNES Associates III / Offices at Crystal Lake	106,345	sf	31.25	%			1,993			1,753		6,756	11/1/23	4.76	%
	Hillsborough 206 Holdings, L.L.C./ Hillsborough 206	160,000	sf	50.00	%			1,962			1,962		-	-	-
	KPG-P 100 IMW JV, LLC / 100 Independence Mall West	339,615	sf	33.33	%			-			1,887		61,500	9/9/16	L+7.00	%	(t)
	Keystone-Penn	1,842,820	sf	(u)				-			-		203,811	(v)	(v)
	Keystone-TriState	1,266,384	sf	(w)				6,140			-		204,843	(x)	(x)
	KPG-MCG Curtis JV, L.L.C./ Curtis Center  (ac)	885,000	sf	50.00	%			59,911			-		(ae)	(ae)	(ae)
	Other
	Plaza VIII & IX Associates, L.L.C./ Vacant land (parking operations)	1,225,000	sf	50.00	%			4,022			3,702		-	-	-
	Roseland/North Retail, L.L.C./ Riverwalk at Port Imperial  (b)	30,745	sf	20.00	%			1,828			1,930		-	-	-
	South Pier at Harborside / Hyatt Regency Jersey City on the Hudson	350	rooms	50.00	%			(af)			(af)		65,643	(y)	(y)
	Stamford SM LLC / Senior Mezzanine Loan  (z)	n/a	n/a	80.00	%			-			36,258		-	-	-
	Other (ad)							907			693		-	-	-
	Totals:						$	247,468		$	181,129	$	1,673,364
		(a)		Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
		(b)		The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the Company is not expected to meaningfully participate in the venture's cash flows in the near term.
		(c)		Through the joint venture, the Company also owns a 12.5 percent interest in a 50,973 square feet retail building ("Shops at 40 Park") and a 25 percent interest in a to-be-built 59-unit, five story multi-family rental development property ("Lofts at 40 Park").
		(d)		The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the payment of the outstanding balance remaining on a note ($975 as of December 31, 2014), and is not expected to meaningfully participate in the venture's cash flows in the near term.
		(e)		Property debt balance consists of: (i) a loan, collateralized by the Metropolitan at 40 Park, with a balance of $38,600 at December 31, 2014, bears interest at 3.25 percent, matures in September 2020 and is interest only through September 2015; (ii) a loan, collateralized by the Shops at 40 Park, with a balance of $6,500 at December 31, 2014, bears interest at 3.63 percent, matures in August 2018 and is interest-only through July 2015; and (iii) a loan, collateralized by the Lofts at 40 Park, with a balance of $1,117, bears interest at LIBOR plus 250 basis points and matures in September 2015.  The Shops at 40 Park mortgage loan also provides for additional borrowing proceeds of $1 million based on certain preferred thresholds being achieved.
		(f)		On August 15, 2014, the Company acquired the equity interests of its joint venture partner in Overlook Ridge JV 2C/3B, L.L.C. for $2.97 million and LR Overlook Phase II, L.L.C., the property-owning entity owned by Overlook Ridge JV, L.L.C., which increased its ownership to 50 percent in two  operating multi-family properties.  The Company also acquired the equity interests of its joint venture partner in LR Overlook Phase III, L.L.C. and  Overlook Ridge, L.L.C. for $0.6 million and $12.99 million respectively, which increased its ownership to 100 percent in developable land (See Note 3: Real Estate Transactions – Acquisitions).
		(g)		Property debt balance consists of: (i) the senior loan, collateralized by the Quarrystone property, with a balance of $52,501 at December 31, 2014, bears interest at LIBOR plus 200 basis, matures in March 2016   and (ii) the junior loan, with a balance of $17,000, bears interest at LIBOR plus 90 basis points, matures in March 2016 and is collateralized by a $17,000 letter of credit provided by an affiliate of the partner.
		(h)		The construction loan has a maximum borrowing amount of $55,500 and provides, subject to certain conditions, two one-year extension options with a fee of 25 basis points each.  The joint venture has a swap agreement that fixes the all-in rate to 3.0875 percent per annum on an initial notional amount of $1,840, increasing to $52,000, for the period from September 3, 2013 to November 2, 2015.
		(i)		The construction loan with a maximum borrowing amount of $83,113 was converted to a permanent loan on December 26,2014 with a maximum borrowing amount of $80,249
		(j)		The construction loan has a maximum borrowing amount of $91,000 and provides, subject to certain conditions, a one-year extension option with a fee of 25 basis points.
		(k)		The Company also owns a 50 percent interest in a vacant land parcel to accommodate the development of approximately 295 additional units of which 252 are currently approved.
		(l)		The construction loan has a maximum borrowing amount of $42,500 and provides, subject to certain conditions, two two-year extension options with a fee of 12.5 basis points for the first two-year extension and 25 basis points for the second two-year extension.
		(m)		The construction loan has a maximum borrowing amount of $73,350 and provides, subject to certain conditions, one-year extension option followed by a six-month extension option with a fee of 25 basis points each. The joint venture has a swap agreement that fixes the all-in rate to 2.79 percent per annum on an initial notional amount of $1,620, increasing to $69,500 for the period from July 1, 2013 to January 1, 2016.
		(n)		The Company also owns a 20 percent residual interest in undeveloped land parcels: parcels 6, I, and J ("Port Imperial North Land") that can accommodate the development of 836 apartment units.
		(o)		The construction loan has a maximum borrowing amount of $77,400 and provides, subject to certain conditions, two one-year extension options with a fee of 25 basis points for each year.
		(p)		The construction loan has a maximum borrowing amount of $57,000 and provides, subject to certain conditions, a one-year extension option with a fee of 25 basis points.
	(q)		The construction loan has a maximum borrowing amount of $23,400 and provides, subject to certain conditions, two one-year extension options with a fee of 20 basis points for each year.
	(r)		The construction/permanent  loan has a maximum borrowing amount of $100,700 with amortization starting in August 2017.
	(s)		The joint venture has a swap agreement that fixes the all-in rate to 3.99375 percent per annum on an initial notional amount of $13,650 and then adjusting in accordance with an amortization schedule, which is effective from October 17, 2011 through loan maturity.
	(t)		The mortgage loan has two one-year extension options, subject to certain conditions, and includes a $25 million construction escrow with a balance of $15.8 million to be drawn at December 31, 2014.
	(u)		The Company’s equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (“IRR”) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
	(v)		Principal balance of $127,600 bears interest at 5.114 percent and matures in August 27, 2023; principal balance of $65,786 bears interest at rates ranging from LIBOR+5.0 percent to LIBOR+5.75 percent and matures in August 27, 2016; principal balance of $10,425 bears interest at LIBOR+6.0 percent matures in August 27, 2015.
	(w)		Includes the Company’s pari-passu interests of $6.2 million in five properties and Company’s subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (“IRR”) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions – Sales).
	(x)		Principal balance of $41,240 bears interest at 4.95 percent and matures on July 1, 2017; principal balance of $70,903 bears interest at rates ranging from 5.65 percent to 6.75 percent and matures on September 9, 2017; principal balance of $14,250 bears interest at 4.88 percent and matures on July 6, 2024; principal balance of $63,400 bears interest at 4.93 percent and matures on July 6, 2044; principal balance of $15,050 bears interest at 4.71 percent and matures on August 6, 2044.
	(y)		Balance includes: (i) mortgage loan, collateralized by the hotel property, with  a balance of $61,519, bears interest at 6.15 percent and matures in November 2016, and (ii) loan with a balance of $4.1 million, bears interest at fixed rates ranging from 6.09 percent to 6.62 percent and matures in August 1, 2020.  The Company posted a $4.1 million letter of credit in support of this loan, half of which is indemnified by the partner.
	(z)		The joint venture collected net proceeds of $47.2 million at maturity, of which the Company received its share of $37.8 million on August 6, 2014.
	(aa)		The construction/permanent loan has a maximum borrowing amount of $192,000.
(ab)See discussion Unconsolidated Joint Venture Transactions following in this footnote.
(ac)Includes undivided interests in the same manner as investments in noncontrolling partnership, pursuant to ASC 970-323-25-12.  See discussion in Unconsolidated Joint Venture Transactions following in this footnote.
(ad)The Company owns other interests in various unconsolidated joint ventures, including interests in assets previously owned and interest in ventures whose businesses are related to its core operations. These ventures are not expected to significantly impact the Company's operations in the near term.
(ae) See Note 10: Mortgages, Loans Payable and Other Obligations for debt secured by interests in these assets.
(af)The negative carrying amount for this venture of $1,854 and $1,706 as of December 31, 2014 and 2013, respectively, were included in accounts payable, accrued expenses and other liabilities.
The following is a summary of the Company’s equity in earnings (loss) of unconsolidated joint ventures for the years ended December 31, 2014 and 2013: (dollars in thousands)
		Year Ended December 31,
Entity / Property Name		2014			2013			2012
Multi-family
Marbella RoseGarden, L.L.C./ Marbella	$	-19		$	-540		$	13
RoseGarden Monaco Holdings, L.L.C./ Monaco		-1,040			-1,560			-311
Rosewood Lafayette Holdings, L.L.C./ Highlands at Morristown Station		-853			-1,131			-197
PruRose Port Imperial South 15, LLC /RiversEdge at Port Imperial		-			-606			-533
Rosewood Morristown, L.L.C. / Metropolitan at 40 Park		-345			-509			-25
Overlook Ridge JV, L.L.C./ Quarrystone at Overlook Ridge		-			-			-
Overlook Ridge JV 2C/3B, L.L.C./The Chase at Overlook Ridge		-384			293			-11
PruRose Riverwalk G, L.L.C./ RiverTrace at Port Imperial		-2,139			-985			-142
Elmajo Urban Renewal Associates, LLC / Lincoln Harbor (Bldg A&C)		-203			-345			-83
Crystal House Apartments Investors LLC / Crystal House		-139			-2,639			-
Portside Master Company, L.L.C./ Portside at Pier One - Bldg 7		-1,163			-421			-5
PruRose Port Imperial South 13, LLC / RiverParc at Port Imperial		-863			-664			-87
Roseland/Port Imperial Partners, L.P./ Riverwalk C		-646			-740			-
RoseGarden Marbella South, L.L.C./ Marbella II		-			-57			-13
Estuary Urban Renewal Unit B, LLC / Lincoln Harbor (Bldg B)		-15			-157			-
Riverpark at Harrison I, L.L.C./ Riverpark at Harrison		-150			-			-
Capitol Place Mezz LLC / Station Townhouses		-75			-			-
Harborside Unit A Urban Renewal, L.L.C. / URL Harborside		-218			-			-
RoseGarden Monaco, L.L.C./ San Remo Land		-			-			-
Grand Jersey Waterfront URA, L.L.C./ Liberty Landing		-54			-77			-
Office
Red Bank Corporate Plaza, L.L.C./ Red Bank		380			372			360
12 Vreeland Associates, L.L.C./ 12 Vreeland Road		106			74			427
BNES Associates III / Offices at Crystal Lake		240			-14			-323
Hillsborough 206 Holdings, L.L.C./ Hillsborough 206		-10			-35			-
KPG-P 100 IMW JV, LLC / 100 Independence Mall West		-1,887			-913			-
Keystone-Penn		-			-			-
Keystone-TriState		-318			-			-
KPG-MCG Curtis JV, L.L.C./ Curtis Center		624			-			-
Other
Plaza VIII & IX Associates, L.L.C./ Vacant land (parking operations)		320			99			30
Roseland/North Retail, L.L.C./ Riverwalk at Port Imperial		-102			-230			-80
South Pier at Harborside / Hyatt Regency Jersey City on the Hudson		2,602			2,519			2,368
Stamford SM LLC / Senior Mezzanine Loan		2,337			3,719			3,078
Other		1,591			2,220			-377
Company's equity in earnings (loss) of unconsolidated joint ventures	$	-2,423		$	-2,327		$	4,089
The following is a summary of the combined financial position of the unconsolidated joint ventures in which the Company had investment interests as of December 31, 2014 and 2013: (dollars in thousands)
			December 31,			December 31,
			2014			2013
Assets:
Rental property, net		$	1,534,812		$	755,038
Loan receivable			-			45,050
Other assets			398,173			582,989
Total assets		$	1,932,985		$	1,383,077
Liabilities and partners'/
members' capital:
Mortgages and loans payable		$	1,060,020		$	637,709
Other liabilities			211,340			87,231
Partners'/members' capital			661,625			658,137
Total liabilities and
partners'/members' capital		$	1,932,985		$	1,383,077
The following is a summary of the combined results from operations of the unconsolidated joint ventures for the period in which the Company had investment interests during the years ended December 31, 2014, 2013 and 2012: (dollars in thousands)
		Year Ended December 31,
		2014			2013			2012
Total revenues	$	305,034		$	255,510		$	68,183
Operating and other expenses		-233,320			-217,739			-37,008
Depreciation and amortization		-42,985			-32,889			-10,139
Interest expense		-32,862			-16,709			-6,775
Net income (loss)	$	-4,133		$	-11,827		$	14,261
Unconsolidated Joint Venture Transactions
2014
Harborside Unit A Urban Renewal, L.L.C.
On May 21, 2014, the Company entered into a joint venture agreement with Ironstate Harborside-A LLC (“ISA”) to form Harborside Unit A Urban Renewal, L.L.C. (“URL-Harborside”), a newly-formed joint venture that will develop, own and operate a high-rise tower of approximately 763 multi-family apartment units above a parking pedestal to be located on land contributed by the Company at its Harborside complex in Jersey City, New Jersey (the “URL Project”).  The construction of the URL Project is estimated to cost a total of approximately $320 million (of which development costs of $65.1 million have been incurred by URL-Harborside through December 31, 2014).  The URL Project is projected to be ready for occupancy by the fourth quarter of 2016.   The URL Project has been awarded up to $33 million in future tax credits (“URL Tax Credits”), subject to certain conditions, from the New Jersey Economic Development Authority.  The venture has an agreement to sell these credits, subject to certain conditions.  On August 1, 2014, the venture obtained a construction/permanent loan with a maximum borrowing amount of $192 million (with no balance currently outstanding as of December 31, 2014), which bears interest at a rate of 5.197 percent and matures in August 2029.  The Company currently expects that it will fund approximately $59.1 million of the remaining development costs of the project, net of the loan financing.
The Company owns an 85 percent interest in URL-Harborside and the remaining interest is owned by ISA, with shared control over major decisions such as, approval of budgets, property financings and leasing guidelines.  Upon entering into the joint venture, the Company’s initial contribution was $30.6 million, which included a capital credit of $30 per approved developable square foot for its contributed land aggregating approximately $20.6 million with the balance consisting of previously incurred development costs, and ISA’s initial contribution was approximately $5.4 million.  Included in the Company’s investment in the unconsolidated joint venture is its land contribution with a carrying amount of $5.5 million.  The Company has funded an additional $19.2 million in development costs for the venture through December 31, 2014.
In general, the operating agreement of URL-Harborside provides that net operating cash flows are distributed first, to the members in respect of preferred return, as defined, until each member shall have received payment of the accrued and unpaid preferred return; and, thereafter, 75 percent to the Company and 25 percent to ISA.
Net cash flows from a capital event are distributed first, to the members in respect of preferred return, as defined, until each member shall have received payment of the accrued and unpaid preferred return; second, to the members pro rata based upon the ratio that their respective capital accounts bear to each other until each member shall have received their respective net capital, as defined; third, to the members at the rate of 75 percent to the Company and 25 percent to ISA until the Company shall have received distributions equal to an 18 percent internal rate of return on the Company’s capital contributions; and, thereafter, to the members, at the rate of 65 percent to the Company and 35 percent to ISA.
KPG-MCG Curtis JV, LLC / Curtis Center
On June 6, 2014, the Company and an affiliate of Keystone Property Group (“KPG”) acquired 50 percent tenants-in-common interests each for $62.5 million in Curtis Center, an 885,000 square foot commercial office property  located at 601 Walnut Street in Philadelphia, Pennsylvania (the “Curtis Center Property”), which amounted to a total purchase price of  approximately $125.0 million for the property.  In connection with the transaction, the Company provided short-term loans to KPG affiliates, as follows:  a 90-day, $52.3 million loan which bore interest at an annual rate of 3.5 percent payable at maturity, which was collateralized by the KPG affiliates’ interest in the Curtis Center Property; and a 90-day, $10 million loan which also bore interest at an annual rate of 3.5 percent payable at maturity.  The $10 million loan was repaid in full on September 2, 2014 and the $52.3 million loan was repaid in full on October 1, 2014.  The investments were funded by the Company primarily through borrowing under its revolving credit facility.  The venture plans to reposition the property into a mixed-use property by converting a portion of existing office space into multi-family rental apartments.
Simultaneous with the acquisition of the Curtis Center Property, the Company and a KPG affiliate formed a new joint venture named KPG-MCG Curtis JV, LLC (the “Curtis Center JV”), which master leased the Curtis Center Property from the acquisition entities for approximately 29 years at market-based terms.  The Company and the KPG affiliate both own a 50 percent interest in the Curtis Center JV, with shared control over major decisions.
In general, the operating agreement of the Curtis Center JV provides that net cash flows from operations and capital events are distributed first, to the members, pro rata in proportion to their unreturned capital contributions, until each member’s unreturned capital contributions have been reduced to zero; and, thereafter, to each member, pro rata, in accordance with their percentage interests.
2013
150 Main Street, L.L.C.
On October 23, 2012, the Company had acquired a 26.25 percent interest in a to-be-built, 108-unit multi-family rental property located in Eastchester, New York (the “Eastchester Project”) for approximately $2.1 million.  The remaining interests in the development project-owning entity, 150 Main Street, L.L.C. (“Eastchester”) was owned 26.25 percent by JMP Eastchester, L.L.C. and 47.5 percent by Hudson Valley Land Holdings, L.L.C. (“HVLH”).
The operating agreement of Eastchester provided, among other things, for the distribution of net operating cash flow to the members, as follows:
	·		to HVLH to the extent of its accrued but unpaid preferred return of eight percent on the unrecovered allocated land value, as defined;
	·		to the members, pro rata, to the extent of their respective accrued but unpaid return of eight percent on their unrecovered capital percentages; and
	·		to the members in accordance with their ownership percentages.
Net cash flows from a capital event are distributed to the members, first, in respect of unrecovered return and then unrecovered capital on a pro rata basis, with any excess in accordance with their ownership percentages.
On August 22, 2013, the Company contributed an additional $4.9 million and the operating agreement of Eastchester was modified which increased the Company’s effective ownership to 76.25 percent, with the remaining 23.75 percent owned by HVLH.  The agreement also provided the Company with control of all major decisions.  Accordingly, effective August 22, 2013, the Company consolidated Eastchester under the provisions of ASC 810, Consolidation.  As the carrying value approximated the fair value of the net assets acquired, there was no holding period gain or loss recognized on this transaction.
The Eastchester Project began construction in late 2013.  Estimated total development costs of $50 million (of which $13.9 million have been incurred through December 31, 2014) are expected to be funded with a $28.8 million construction loan and the balance of $21.2 million from member’s capital, of which the Company’s share is $20.9 million.
Crystal House Apartments Investors LLC
On March 20, 2013, the Company entered into a joint venture with a fund advised by UBS Global Asset Management (“UBS”) to form Crystal House Apartments Investors LLC (“CHAI”) which acquired the 828-unit multi-family property known as Crystal House located in Arlington, Virginia (“Crystal House Property”) for approximately $262.5 million.  The Company acquired a 25 percent interest in the Crystal House property and a 50 percent interest in the vacant land for approximately $30.2 million.  The acquisition included vacant land to accommodate the development of approximately 295 additional units of which 252 are currently approved.
In general, the operating agreement of CHAI provides that net operating cash flows are distributed to the members in accordance with ownership percentages.  Net cash flows from a capital event are distributed first to the members in accordance with ownership percentages until they receive a nine percent IRR, as defined, with any excess distributed 50 percent to the Company and 50 percent to UBS.
CHAI obtained a mortgage loan on the acquired property, which has a balance of $165 million as of December 31, 2014, bears interest at 3.17 percent and matures in April 2020.  The loan, which is interest-only during the initial 5-year term and amortizable over a 30-year period for the remaining term, is collateralized by the Crystal House Property.
KPG-P 100 IMW JV, LLC
On December 9, 2013, the Company entered into a joint venture partnership with the Keystone Property Group (“KPG”) and Parkway Corporation (“Parkway”) to form KPG-P 100 IMW JV, LLC (“KPG-P”).  The Company acquired a 33.33 percent indirect interest in KPG-IMW Owner, LLC (“KPG-IMW”), an entity that owns a nine- story, approximately 400,000 square-foot office building located at 100 Independence Mall West in Philadelphia, Pennsylvania (“100 IMW Property”) for $2.8 million.  The 100 IMW Property was acquired for approximately $40.5 million.  As part of a more than $20-million reinvestment strategy for 100 IMW Property, the partnership is planning upgrades to the building’s common areas, as well as build-out of offices and the conversion of approximately 55,000 square feet of lower-level space into a 110-space parking garage that will be managed by Parkway.
The Company, through subsidiaries, owns 57.7677 percent of KPG-MCG IMW, LLC (“KPG-MCG”) with the remaining interest owned by Fawkes Investments, LP.  KPG-MCG owns a 57.7024 percent interest in KPG-P and the remaining interests are owned 17.8928 percent by KPG and 24.4048 percent by Parkway.
In general, the operating agreement of KPG-P provides that net operating cash flows are distributed first, to the members in proportion to their unreturned capital contributions, until each member’s unreturned capital contributions have been reduced to zero; and, thereafter, to the members, in accordance with their percentage interests.  Net cash flows from a capital event are distributed first, to the members in proportion to the members’ unreturned capital contributions, until each member’s unreturned capital contributions have been reduced to zero; second, to the members in proportion to the members’ unreturned deferred capital contributions, until each member’s deferred unreturned capital contributions have been reduced to zero; and, thereafter, to the members in accordance with their percentage interests.
KPG-IMW obtained a mortgage loan collateralized by 100 IMW Property, which has a balance of $61.5 million as of December 31, 2014, bears interest at LIBOR plus 700 basis points and matures in September 2016 and has two one-year extension options, subject to certain conditions and includes a $25 million construction reserve with a balance of $15.8 million at December 31, 2014.
Capitol Place Mezz LLC
On December 23, 2013, the Company entered into a joint venture with FB Capitol Place LLC (“FB”) to form Capitol Place Mezz LLC (“Capitol”).  The Company acquired a 50 percent ownership interest in an entity that owns a 377-unit multi-family development project that includes approximately 25,000 square feet of retail space and a 309-space underground parking garage, which are currently under construction, located at 701 2nd Street, NE in Washington, D.C. (the “WDC Project”) for approximately $46.5 million. It is expected that the WDC Project will be completed by mid-2015, with leasing beginning in the first quarter 2015.  The venture expects to incur approximately $194.4 million in total estimated costs to complete the WDC Project, of which $171.5 million has been incurred through December 31, 2014.  The Company is not required to fund any additional costs (with some limitation) for the completion of the WDC Project beyond its $46.5 million initial contribution.
In general, the operating agreement of Capitol provides that net cash flows from a capital event are distributed first, to each holder of a member loan, as defined, until all member loans have been paid in full; second, to FB until FB has received the aggregate amount of $2,500,000; and third, to the members in accordance with their percentage interests.  The operating agreement also includes specific provisions, including a right of first offer on all development deals in the D.C. metro area that involve either party, with specific qualifications on any properties in Arlington County, Virginia.
The WDC Project has a 20-year construction loan of $100.7 million with a balance of $74 million as of December 31, 2014.  The loan bears interest at 4.82 percent and matures in July 2033.  The loan is amortizable over a 30-year period starting in August 2017.

Deferred_Charges_Goodwill_And_

Deferred Charges, Goodwill And Other Assets, Net	12 Months Ended
	Dec. 31, 2014
Deferred Charges, Goodwill And Other Assets, Net [Abstract]
Deferred Charges, Goodwill And Other Assets, Net	5.DEFERRED CHARGES, GOODWILL AND OTHER ASSETS, NET
			December 31,
	(dollars in thousands)		2014			2013
	Deferred leasing costs	$	239,138		$	258,648
	Deferred financing costs		24,042			25,366
			263,180			284,014
	Accumulated amortization		-122,358			-131,669
	Deferred charges, net		140,822			152,345
	Notes receivable (1)		21,491			21,986
	In-place lease values, related intangibles and other assets, net (2) (3)		6,565			13,659
	Goodwill		2,945			2,945
	Prepaid expenses and other assets, net		32,827			27,584
	Total deferred charges, goodwill and other assets, net	$	204,650		$	218,519
		-1		Includes as of December 31, 2014: a mortgage receivable for $10.4 million which bears interest at LIBOR plus six percent and matures in August 2015; a note receivable for $7.8 million which bears interest at eight percent and matures in October 2017; and an interest-free note receivable with a net present value of $3.3 million and matures in April 2023.  The Company believes these balances are fully collectable.
		-2		In accordance with ASC 805, Business Combinations, the Company recognizes rental revenue of acquired above and below market lease intangibles over the terms of the respective leases.  The impact of amortizating the acquired above and below-market lease intangibles increased revenue by approximately $0.7 million, $1.5 million and $1.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.  The following table summarizes, as of December 31, 2014, the scheduled amortization of the Company’s acquired above and below-market lease intangibles for each of the five succeeding years (dollars in thousands).
			Acquired Above-			Acquired Below-
			Market Lease			Market Lease			Total
	Year		Intangibles			Intangibles			Amortization
	2015	$	-338		$	564		$	226
	2016		-288			370			82
	2017		-261			364			103
	2018		-233			310			77
	2019		-209			156			-53
		-3		In accordance with ASC 805, Business Combinations, the value of acquired in-place lease intangibles are amortized to expense over the remaining initial terms of the respective leases.  The impact of the amortization of acquired in-place lease values is included in depreciation and amortization expense and amounted to approximately $6.9 million, $10.7 million and $10.2 million for the years ended December 31, 2014, 2013 and 2012, respectively.  The following table summarizes, as of December 31, 2014, the scheduled amortization of the Company’s acquired in-place lease values for each of the five succeeding years (dollars in thousands).
	Year
	2015		$	1,231
	2016			1,224
	2017			918
	2018			-
	2019			-
	DERIVATIVE FINANCIAL INSTRUMENTS
	The Company does not have any derivative instruments designated as cash flow hedges.  The following table summarizes the notional and fair value of the Company’s derivative financial instruments, designated as fair value hedges, as of December 31, 2014 (dollars in thousands):
			Notional			Strike			Effective	Expiration
			Value	(a)		Rate			Date	Date		Fair Value
	LIBOR Cap	$	51,000			1.5	%		Sep-14	Oct-15	$	1
	LIBOR Cap		24,000			1.5	%		Sep-14	Oct-15		1
	LIBOR Cap		51,000			1.75	%		Oct-15	Oct-16		64
	LIBOR Cap		24,000			1.75	%		Oct-15	Oct-16		29
											$	95
		(a)		The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks.
	The Company includes these derivative financial instruments in deferred charges, goodwill and other assets, net.  As changes in the fair value of these derivative financial instruments are recorded in earnings, during the year ended December 31, 2014, the Company recorded a loss on the change in fair value of $79,000, which is included in interest and other investment income in the consolidated statements of operations.

Restricted_Cash

Restricted Cash	12 Months Ended
	Dec. 31, 2014
Restricted Cash [Abstract]
Restricted Cash	6.RESTRICTED CASH
	Restricted cash generally includes tenant and resident security deposits for certain of the Company’s properties, and escrow and reserve funds for debt service, real estate taxes, property insurance, capital improvements, tenant improvements, and leasing costs established pursuant to certain mortgage financing arrangements, and is comprised of the following:  (dollars in thousands)
			December 31,
			2014		2013
	Security deposits	$	7,795	$	8,534
	Escrow and other reserve funds		26,450		11,260
	Total restricted cash	$	34,245	$	19,794

Discontinued_Operations

Discontinued Operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations [Abstract]
Discontinued Operations	7.DISCONTINUED OPERATIONS
	On January 1, 2014, the Company early adopted the new discontinued operations accounting standard and as the properties sold during the year ended December 31, 2014 did not represent a strategic shift (as the Company is not entirely exiting markets or property types), they have not been reflected as part of discontinued operations.  See Note 3: Real Estate Transactions – Sales.
	During the year ended December 31, 2013, the Company disposed of 24 office properties located in New York, New Jersey, Pennsylvania and Connecticut aggregating 3 million square feet and three developable land parcels for total net sales proceeds of approximately $390.6 million.  The Company has presented these properties as discontinued operations in its statements of operations for all periods presented.  See Note 3: Real Estate Transactions – Sales.
	During the year ended December 31, 2012, as the Company disposed of 2200 Renaissance Boulevard in King of Prussia, Pennsylvania; 95 Chestnut Ridge Road in Montvale, New Jersey; and three office buildings in Moorestown, New Jersey, the Company has presented these properties as discontinued operations in its statements of operations for all periods presented.
	The following table summarizes income from discontinued operations and the related realized gains (losses) and unrealized losses on disposition of rental property and impairments, net, for the years ended December 31, 2013 and 2012: (dollars in thousands)
		Year Ended December 31,
			2013			2012
	Total revenues	$	33,601		$	66,882
	Operating and other expenses		-13,454			-26,484
	Depreciation and amortization		-8,218			-17,765
	Interest expense		-118			-755
	Income from discontinued operations		11,811			21,878
	Loss from early extinguishment of debt		-703			-
	Impairments (1)		-23,851			-8,400
	Unrealized losses on disposition of rental property (2)		-			-9,213
	Realized gains on disposition of rental property		83,371			4,438
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		59,520			-13,175
	Total discontinued operations, net	$	70,628		$	8,703
	(1)Represents impairment charges recorded on certain properties prior to their sale.
	(2)Represents valuation allowances on properties identified as held for sale in 2012, as follows:
		(i)		At March 31, 2012, the Company identified as held for sale its 47,700 square foot office building located at 95 Chestnut Ridge Road in Montvale, New Jersey. The Company determined that the carrying amount of this property was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $0.5 million at March 31, 2012. On July 25, 2012, the Company sold the building for approximately $4.0 million (with no gain from the sale).
		(ii)		At March 31, 2012, the Company identified as held for sale three office buildings totaling 222,258 square feet in Moorestown, New Jersey. The Company determined that the aggregate carrying amount of these properties was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $1.6 million at June 30, 2012. On November 7, 2012, the Company sold the buildings for approximately $19.4 million and recognized a loss of approximately $0.1 million from the sale.
		(iii)		At December 31, 2012, the Company identified as held for sale its 248,400 square foot office building located at 19 Skyline Drive in Hawthorne, New York. The Company determined that the carrying amount of this property was not expected to be recovered from estimated sales proceeds and accordingly recognized a valuation allowance of $7.1 million at December 31, 2012. Also at December 31, 2012, the Company identified as held for sale its 204,057 square foot office building located at 55 Corporate Drive in Bridgewater, New Jersey. The two properties held for sale at December 31, 2012 carried an aggregate book value of $60.9 million, net of accumulated depreciation of $16.8 million and a valuation allowance of $7.1 million.  As of April 10, 2013, the Company sold 19 Skyline Drive for approximately $16.1 million and recognized a gain of approximately $0.1 million.  As of April 26, 2013, the Company sold 55 Corporate Drive for approximately $71 million and recognized a gain of approximately $19.7 million.

Senior_Unsecured_Notes

Senior Unsecured Notes	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Senior Unsecured Notes	8.SENIOR UNSECURED NOTES
	A summary of the Company’s senior unsecured notes as of December 31, 2014 and 2013 is as follows: (dollars in thousands)
			December 31,			Effective
			2014		2013	Rate (1)
	5.125% Senior Unsecured Notes, due February 15, 2014 (2)		-	$	200,030	5.110	%
	5.125% Senior Unsecured Notes, due January 15, 2015 (3)		-		149,902	5.297	%
	5.800% Senior Unsecured Notes, due January 15, 2016	$	200,086		200,161	5.806	%
	2.500% Senior Unsecured Notes, due  December 15, 2017		249,150		248,855	2.803	%
	7.750% Senior Unsecured Notes, due August 15, 2019		249,013		248,799	8.017	%
	4.500% Senior Unsecured Notes, due April 18, 2022		299,565		299,505	4.612	%
	3.150% Senior Unsecured Notes, due May 15, 2023		269,930		269,323	3.517	%
	Total senior unsecured notes	$	1,267,744	$	1,616,575
	(1)Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.
	(2)On February 17, 2014, the Company repaid these notes at their maturity using available cash and borrowings on the Company’s unsecured revolving credit facility.
	(3)These notes were redeemed on December 17, 2014. The redemption price, including a make-whole premium, was 100.380 percent of the principal amount of the Notes, plus all accrued and unpaid interest up to the Redemption Date. The Company funded the redemption price, including accrued and unpaid interest, of approximately $153.8 million using available cash and borrowings on the Company’s unsecured revolving credit facility.  In connection with the redemption, the Company recorded approximately $0.6 million as a loss from early extinguishment of debt (including the write-off of unamortized deferred financing costs).
	The terms of the Company’s senior unsecured notes include certain restrictions and covenants which require compliance with financial ratios relating to the maximum amount of debt leverage, the maximum amount of secured indebtedness, the minimum amount of debt service coverage and the maximum amount of unsecured debt as a percent of unsecured assets.   The Company was in compliance with its debt covenants as of December 31, 2014.

Unsecured_Revolving_Credit_Fac

Unsecured Revolving Credit Facility	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Unsecured Revolving Credit Facility	9.UNSECURED REVOLVING CREDIT FACILITY
	On July 16, 2013, the Company amended and restated its unsecured revolving credit facility with a group of 17 lenders.  The $600 million facility is expandable to $1 billion and matures in July 2017.  It has two six-month extension options each requiring the payment of a 7.5 basis point fee.  The interest rate on outstanding borrowings (not electing the Company’s competitive bid feature) and the facility fee on the current borrowing capacity payable quarterly in arrears are based upon the Operating Partnership’s unsecured debt ratings, as follows:
	Operating Partnership's	Interest Rate -
	Unsecured Debt Ratings:	Applicable Basis Points	Facility Fee
	Higher of S&P or Moody's	Above LIBOR	Basis Points
	No ratings or less than BBB-/Baa3	170.0	35.0
	BBB- or Baa3 (current)	130.0	30.0
	BBB or Baa2	110.0	20.0
	BBB+ or Baa1	100.0	15.0
	A- or A3 or higher	92.5	12.5
	The facility has a competitive bid feature, which allows the Company to solicit bids from lenders under the facility to borrow up to $300 million at interest rates less than those above.
	The terms of the unsecured facility include certain restrictions and covenants which limit, among other things the incurrence of additional indebtedness, the incurrence of liens and the disposition of real estate properties (to the extent that: (i) such property dispositions cause the Company to default on any of the financial ratios of the facility described below, or (ii) the property dispositions are completed while the Company is under an event of default under the facility, unless, under certain circumstances, such disposition is being carried out to cure such default), and which require compliance with financial ratios relating to the maximum leverage ratio (60 percent), the maximum amount of secured indebtedness (40 percent), the minimum amount of fixed charge coverage (1.5 times), the maximum amount of unsecured indebtedness (60 percent), the minimum amount of unencumbered property interest coverage (2.0 times) and certain investment limitations (generally 15 percent of total capitalization).  If an event of default has occurred and is continuing, the Corporation will not make any excess distributions except to enable the Corporation to continue to qualify as a REIT under the Code.  The Company was in compliance with its debt covenants as of December 31, 2014.
	The lending group for the credit facility consists of: JPMorgan Chase Bank, N.A., as administrative agent; Bank of America, N.A.,  as syndication agent; Deutsche Bank AG New York Branch; U.S. Bank National Association and Wells Fargo Bank, N.A., as documentation agents; Capital One, National Association; Citibank N.A.; Comerica Bank; PNC Bank, National Association; SunTrust Bank; The Bank of Tokyo-Mitsubishi UFJ, LTD.; The Bank of New York Mellon; as managing agents; and Compass Bank; Branch Banking and Trust Company; TD Bank, N.A.; Citizens Bank of Pennsylvania; Mega International Commercial Bank Co., LTD.  New York Branch, as participants.
	As of December 31, 2014 and 2013, the Company had no outstanding borrowings under its unsecured revolving credit facility.
	Through July 15, 2013, the Company had a $600 million unsecured revolving credit facility, which had an interest rate on outstanding borrowings of LIBOR plus 125 basis points and a facility fee of 25 basis points.

Mortgages_Loans_Payable_And_Ot

Mortgages, Loans Payable And Other Obligations	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Mortgages, Loans Payable And Other Obligations	10.MORTGAGES, LOANS PAYABLE AND OTHER OBLIGATIONS
	The Company has mortgages, loans payable and other obligations which primarily consist of various loans collateralized by certain of the Company’s rental properties.  As of December 31, 2014,  30 of the Company’s properties, with a total book value of approximately $998 million, are encumbered by the Company’s mortgages and loans payable.  Payments on mortgages, loans payable and other obligations are generally due in monthly installments of principal and interest, or interest only.  Except as noted below, the Company was in compliance with its debt covenants as of December 31, 2014.
	A summary of the Company’s mortgages, loans payable and other obligations as of December 31, 2014 and 2013 is as follows: (dollars in thousands)
				Effective				December 31,
	Property Name	Lender		Rate (a)				2014			2013	Maturity
	6301 Ivy Lane (b)	RGA Reinsurance Company		5.520	%			-		$	5,447	-
	395 West Passaic (c)	State Farm Life Insurance Co.		6.004	%			-			9,719	-
	35 Waterview Boulevard (d)	Wells Fargo CMBS		6.348	%			-			18,417	-
	233 Canoe Brook Road (e)	The Provident Bank		4.375	%			-			3,877	-
	Port Imperial South 4/5 (f)	Wells Fargo Bank N.A.	LIBOR+3.50		%			-			36,950	-
	6 Becker, 85 Livingston,	Wells Fargo CMBS		10.260	%		$	65,035			64,233	8/11/14	(h)
	75 Livingston &
	20 Waterview (g)
	4 Sylvan	Wells Fargo CMBS		10.260	%			14,575			14,538	8/11/14	(h)
	10 Independence	Wells Fargo CMBS		10.260	%			16,924			16,638	8/11/14	(h)
	Overlook - Site IIID,IIIC, IIIA (i)	Wells Fargo Bank N.A.	LIBOR+3.50		%			17,260			-	3/2/15
	Overlook - Site IIB (Quarrystone I) (i)	Wells Fargo Bank N.A.	LIBOR+2.50		%			5,787			-	4/14/15
	9200 Edmonston Road (j)	Principal Commercial Funding L.L.C.		5.534	%			3,951			4,115	5/1/15
	Port Imperial South	Wells Fargo Bank N.A.	LIBOR+1.75		%			44,119			43,278	9/19/15
	4 Becker	Wells Fargo CMBS		9.550	%			39,421			38,820	5/11/16
	5 Becker (k)	Wells Fargo CMBS		12.830	%			13,867			13,092	5/11/16
	210 Clay  (l)	Wells Fargo CMBS		13.420	%			13,330			12,767	5/11/16
	Curtis Center (m)	CCRE & PREFG	LIBOR+5.912		%	(p)		64,000			-	10/9/16
	Various (n)	Prudential Insurance		6.332	%			145,557			147,477	1/15/17
	150 Main St.	Webster Bank	LIBOR+2.35		%			1,193	(r)		-	3/30/17
	23 Main Street	JPMorgan CMBS		5.587	%			29,210			29,843	9/1/18
	Harborside Plaza 5	The Northwestern Mutual Life		6.842	%			221,563			225,139	11/1/18
		Insurance Co. & New York Life
		Insurance Co.
	100 Walnut Avenue	Guardian Life Insurance Co.		7.311	%			18,542			18,792	2/1/19
	One River Center (o)	Guardian Life Insurance Co.		7.311	%			42,476			43,049	2/1/19
	Park Square	Wells Fargo Bank N.A.	LIBOR+1.872		%	(q)		27,500			-	4/10/19
	Port Imperial South 4/5 Retail	American General Life & A/G PC		4.559	%			4,000			-	12/1/21
	Port Imperial South 4/5 Garage	American General Life & A/G PC		4.853	%			32,600			-	12/1/29
	Total mortgages, loans payable and other obligations						$	820,910		$	746,191
		(a)		Reflects effective rate of debt, including deferred financing costs, comprised of the cost of terminated treasury lock agreements (if any), debt initiation costs, mark-to-market adjustment of acquired debt and other transaction costs, as applicable.
		(b)		On April 1, 2014, the Company repaid the mortgage loan at par, using available cash.
		(c)		On May 1, 2014, the Company repaid the mortgage loan at par, using available cash.
		(d)		On May 12, 2014, the Company repaid the mortgage loan at par, using borrowings on the Company’s unsecured revolving credit facility.
		(e)		On April 30, 2014, the Company repaid the mortgage loan at par, using available cash.
		(f)		On November 3, 2014, the Company refinanced the mortgage loan with a different lender
		(g)		Mortgage is cross collateralized by the four properties.
		(h)		The loan was not repaid at maturity and the Company has begun discussions with the lender regarding a potential deed-in-lieu of foreclosure in satisfaction of the obligation.
		(i)		On August 15, 2014, the Company assumed these loans as a result of its acquisition of interests which increased its ownership to 100 percent in certain previously unconsolidated joint ventures which owned developable land.
		(j)		The mortgage loan originally matured on May 1, 2013.  The maturity date was extended until May 1, 2015 with the same interest rate.  Excess cash flow, as defined, is being held by the lender for re-leasing costs.  The deed for the property was placed in escrow and is available to the lender in the event of default or non-payment at maturity.
		(k)		The cash flow from this property is insufficient to cover operating costs and debt service.  Consequently, the Company notified the lender and suspended debt service payments in August 2013.  The Company has begun discussions with the lender regarding a deed-in-lieu of foreclosure and began remitting available cash flow to the lender effective August 2013.
		(l)		The cash flow from this property is insufficient to cover operating costs and debt service.  Consequently, the Company notified the lender and suspended debt service payments in January 2015.
		(m)		The Company owns a 50 percent tenants-in-common interest in the Curtis Center Property.  The Company’s $64.0 million loan consists of its 50 percent interest in a $102 million senior loan with a current rate of 3.455 percent at December 31, 2014 and its 50 percent interest in a $26 million mezzanine loan (with a maximum borrowing capacity of $48 million) with a current rate of 9.661 percent at December 31, 2014.  The senior loan rate is based on a floating rate of one-month LIBOR plus 329 basis points and the mezzanine loan rate is based on a floating rate of one-month LIBOR plus 950 basis points.  The Company has entered into LIBOR caps for the periods of the loans.  The loans provide for three one-year extension options.
		(n)		Mortgage is cross collateralized by seven properties.  The Company has agreed, subject to certain conditions, to guarantee repayment of a portion of the loan.
		(o)		Mortgage is collateralized by the three properties comprising One River Center.
		(p)		The effective interest rate includes amortization of deferred financing costs of 1.362 percent.
		(q)		The effective interest rate includes amortization of deferred financing costs of 0.122 percent.
		(r)		This construction loan has a maximum borrowing capacity of $28.8 million.
	SCHEDULED PRINCIPAL PAYMENTS
	Scheduled principal payments for the Company’s senior unsecured notes (see Note 8), unsecured revolving credit facility (see Note 9) and mortgages, loans payable and other obligations as of December 31, 2014 are as follows: (dollars in thousands)
			Scheduled			Principal
	Period		Amortization			Maturities			Total
	2015	$	8,811		$	167,589		$	176,400
	2016		8,311			333,272			341,583
	2017		7,275			392,345			399,620
	2018		7,311			231,536			238,847
	2019		723			331,567			332,290
	Thereafter		6,329			605,205			611,534
	Sub-total		38,760			2,061,514			2,100,274
Adjustment for unamortized debt
discount/premium, net, as of
31-Dec-14		-11,620			-			-11,620
Totals/Weighted Average	$	27,140		$	2,061,514		$	2,088,654
CASH PAID FOR INTEREST AND INTEREST CAPITALIZED
Cash paid for interest for the years ended December 31, 2014,  2013 and 2012 was $119,664,000,  $123,213,000 and $120,089,000, respectively.  Interest capitalized by the Company for the years ended December 31, 2014,  2013 and 2012 was $15,470,000, $12,885,000, and $4,342,000, respectively (of which these amounts included $4,646,000,  $1,326,000 and $235,000 for the years ended December 31, 2014, 2013 and 2012, respectively, for interest capitalized on the Company’s investments in unconsolidated joint ventures which were substantially in development).
SUMMARY OF INDEBTEDNESS
As of December 31, 2014, the Company’s total indebtedness of $2,088,654,000 (weighted average interest rate of 5.64 percent) was comprised of $159,860,000 of variable rate mortgage debt (weighted average rate of 3.83 percent) and fixed rate debt and other obligations of $1,928,794,000 (weighted average rate of 5.79 percent).
As of December 31, 2013, the Company’s total indebtedness of $2,362,766,000 (weighted average interest rate of 5.62 percent) was comprised of $80,228,000 of variable rate mortgage debt (weighted average rate of 2.74 percent) and fixed rate debt and other obligations of $2,282,538,000 (weighted average rate of 5.72 percent).

MackCali_Realty_LPs_Partners_C

Mack-Cali Realty, L.P's Partners' Capital	12 Months Ended
	Dec. 31, 2014
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Mack-Cali Realty, L.P's Partners' Capital	11.MACK-CALI REALTY, L.P.’S PARTNERS’ CAPITAL
	Partners’ Capital in the accompanying consolidated financial statements relates to (a) General Partners’ capital consisting of common units in the Company held by the General Partner, and (b) Limited Partners’ capital consisting of common units held by the limited partners.
	Any transactions resulting in the issuance of additional common and preferred stock of the Corporation result in a corresponding issuance by the Company of an equivalent amount of common and preferred units to the Corporation.
	GENERAL PARTNERS’ CAPITAL
	REPURCHASE OF GENERAL PARTNER UNITS
	In September 2012, the Corporation’s Board of Directors renewed and authorized an increase to the Corporation’s repurchase program (“Repurchase Program”).  The Corporation has authorization to repurchase up to $150 million of its outstanding common stock under the renewed Repurchase Program, which it may repurchase from time to time in open market transactions at prevailing prices or through privately negotiated transactions.  The Corporation has purchased and retired 394,625 shares of its outstanding common stock for an aggregate cost of approximately $11 million (all of which occurred in the year ended December 31, 2012), with a remaining authorization under the Repurchase Program of $139 million.  Concurrent with these purchases, the Corporation sold to the Company 394,625 common units for approximately $11 million.
	DIVIDEND REINVESTMENT AND STOCK PURCHASE PLAN
	The Corporation has a Dividend Reinvestment and Stock Purchase Plan (the “DRIP”) which commenced in March 1999 under which approximately 5.5 million shares of the Corporation’s common stock have been reserved for future issuance.  The DRIP provides for automatic reinvestment of all or a portion of a participant’s dividends from the Corporation’s shares of common stock.  The DRIP also permits participants to make optional cash investments up to $5,000 a month without restriction and, if the Corporation waives this limit, for additional amounts subject to certain restrictions and other conditions set forth in the DRIP prospectus filed as part of the Corporation’s effective registration statement on Form S-3 filed with the SEC for the approximately 5.5 million shares of the Corporation’s common stock reserved for issuance under the DRIP.
	STOCK OPTION PLANS
	In May 2013, the Corporation established the 2013 Incentive Stock Plan (the “2013 Plan”) under which a total of 4,600,000 shares have been reserved for issuance. In May 2004, the Corporation established the 2004 Incentive Stock Plan (the “2004 Plan”) under which a total of 2,500,000 shares had been reserved for issuance.  The 2004 Plan was terminated upon establishment of the 2013 Plan.  No options were granted under the 2004 Plan.  In September 2000, the Corporation established the 2000 Employee Stock Option Plan (“2000 Employee Plan”) and the Amended and Restated 2000 Director Stock Option Plan (“2000 Director Plan” and together with the 2000 Employee Plan, the “2000 Plans”).  In May 2002, shareholders of the Corporation approved amendments to both of the 2000 Plans to increase the total shares reserved for issuance under both of the 2000 Plans from 2,700,000 to 4,350,000 shares of the Corporation’s common stock (from 2,500,000 to 4,000,000 shares under the 2000 Employee Plan and from 200,000 to 350,000 shares under the 2000 Director Plan).  As the 2000 Plans expired in 2010, stock options may no longer be issued under those plans.  Stock options granted under the 2000 Employee Plan became exercisable over a five-year period.  All stock options granted under the 2000 Director Plan became exercisable in one year.  All options were granted at the fair market value at the dates of grant and have terms of 10 years.  As of December 31, 2014 and 2013, the stock options outstanding had a weighted average remaining contractual life of approximately 4.9 and 0.7 years, respectively.
	Information regarding the Corporation’s stock option plans is summarized below:
					Weighted			Aggregate
					Average			Intrinsic
		Shares			Exercise			Value
		Under Options			Price			$(000’s)
	Outstanding at January 1, 2012	183,870		$	29.51			-
	Exercised/Cancelled	-			-
	Outstanding at December 31, 2012  ($28.47 – $45.47)	183,870		$	29.51			-
	Lapsed or Cancelled	-168,870			28.53
	Outstanding at December 31, 2013  ($35.59 – $45.47)	15,000		$	40.54			-
	Granted	5,000			21.25
	Lapsed or Cancelled	-10,000			38.07
	Outstanding at December 31, 2014  ($21.25 – $45.47)	10,000		$	33.36			-
	Options exercisable at December 31, 2014	5,000
	Available for grant at December 31, 2014	4,424,013
	The weighted average fair value of options granted during the year ended December 31, 2014 was $1.71 per option. The fair value of each option grant is estimated on the date of grant using the Black-Scholes model.  The following weighted average assumptions are included in the Company’s fair value calculations of stock options granted during the year ended December 31, 2014:
	Expected life (in years)		6
	Risk-free interest rate		1.50	%
	Volatility		20.26	%
	Dividend yield		5.65	%
	There were no stock options exercised under all stock option plans for the years ended December 31, 2014,  2013 and 2012.  The Corporation has a policy of issuing new shares to satisfy stock option exercises.
	The Company recognized stock options expense of $4,000,  zero and zero for the years ended December 31, 2014,  2013 and 2012, respectively.
	RESTRICTED STOCK AWARDS
	The Corporation has issued stock awards (“Restricted Stock Awards”) to officers, certain other employees, and nonemployee members of the Board of Directors of the Corporation, which allow the holders to each receive a certain amount of shares of the Corporation’s common stock generally over a one to seven-year vesting period, of which 346,946 unvested shares were legally outstanding at December 31, 2014.  Of the Restricted Stock Awards issued to executive officers and senior management, 210,000 were contingent upon the Corporation meeting certain performance goals to be set by the Executive Compensation and Option Committee of the Board of Directors of the Corporation each year (“Performance Shares”), with the remaining based on time and service.  These Performance Shares are not considered granted until the performance goals are set.  All currently outstanding and unvested Restricted Stock Awards provided to the officers and certain other employees were issued under the 2013 Plan and 2004 Plan.  Currently outstanding and unvested Restricted Stock Awards provided to directors were issued under the 2013 Plan.
	On September 12, 2012, the Board of Directors of the Corporation approved the recommendations and ratified the determinations of the Executive Compensation and Option Committee of the Board of Directors of the Corporation (the “Committee”) with respect to new Restricted Stock Awards totaling 319,667 shares for those executive officers in place on such date.  The new Restricted Stock Awards may vest commencing January 1, 2014 and with the number of Restricted Stock Awards scheduled to be vested and earned on each vesting date on an annual basis over a five to seven year vesting schedule, with each annual vesting of each tranche of Restricted Stock Awards being subject to the attainment of annual performance targets to be set by the Committee for each year.  As the Committee determined that the performance targets for the year ended December 31, 2013 were not satisfied, 63,933 shares due to vest on January 1, 2014 did not vest. Such shares may vest on any subsequent vesting date provided that the performance targets for the subsequent calendar year are met.  Amounts recorded as compensation expense pertaining to these shares during the year ended December 31, 2013 were reversed.  In connection with the departure of two executive officers effective March 31, 2014, the Corporation agreed to grant and accelerate vesting of 109,667 shares of Restricted Stock Awards on April 1, 2014.  In connection with the announcement of the departure of the Corporation’s president and chief executive officer effective May 11, 2015, the Corporation agreed to vest 84,000 Performance Shares and to grant and accelerate the vesting of 126,000 Performance Shares on the Separation Date.
	Information regarding the Restricted Stock Awards grant activity is summarized below:
					Weighted-Average
					Grant – Date
		Shares			Fair Value
	Outstanding at January 1, 2012	187,447		$	33.82
	Granted (a)	70,758			25.28
	Vested	-123,877			31.30
	Outstanding at December 31, 2012	134,328		$	31.65
	Granted (b) (c)	168,841			23.99
	Vested	-149,463			29.63
	Forfeited	-146			26.36
	Outstanding at December 31, 2013	153,560		$	25.20
	Granted (d) (e) (f)	376,719			20.04
	Vested	-183,214			22.37
	Forfeited	-119			26.36
	Outstanding at December 31, 2014	346,946		$	21.09
	(a)Included in the 70,758 Restricted Stock Awards granted in 2012 were 42,273 awards granted to the Corporation’s three executive officers, Mitchell E. Hersh, Barry Lefkowitz and Roger W. Thomas.
	(b)Included in the 168,841 Restricted Stock Awards granted in 2013 were 106,933 awards granted to the Corporation’s four executive officers, Mitchell E. Hersh, Barry Lefkowitz, Roger W. Thomas and Anthony Krug.
	(c)Includes 63,933 Performance Shares which were legally granted in 2013 for which the 2013 performance goals were not met, which may be earned if subsequent years’ performance goals are met.
	(d)Included in the 376,719 Restricted Stock Awards granted in 2014 were 8,211 awards granted to the Corporation’s two executive officers, Anthony Krug and Gary Wagner.
	(e)Includes 42,000 Performance Shares which were legally granted in 2013 for which the 2014 performance goals were set by the Committee on March 31, 2014.  Also includes 87,734 shares which were additionally considered granted for accounting purposes to two executive officers in connection with their departure effective March 31, 2014, which vested on April 1, 2014.
	(f)Includes 126,000 Performance Shares which were legally granted in 2013 for which future performance goals had not yet been set by the Committee.  These awards were not considered granted for accounting purposes until these goals are set.  These were  considered granted in 2014 for accounting purposes in connection with the announcement of the departure of Mitchell E. Hersh in the fourth quarter 2014.
	As of December 31, 2014, the Company had $1.5 million of total unrecognized compensation cost related to unvested Restricted Stock Awards granted under the Corporation’s stock compensation plans.  That cost is expected to be recognized over a weighted average period of 1.5 years.
	TSR-BASED AWARDS
	Also on September 12, 2012, the Board of Directors of the Corporation approved the recommendations and ratified the determinations of the Committee with respect to new multi-year TSR based awards (the “TSR-Based Awards”) totaling 5,160 performance shares (the “TSR Performance Shares”) for those executive officers in place on such date, each TSR Performance Share evidencing the right to receive $1,000 in the Corporation’s common stock upon vesting.  In accordance with the amended and restated TSR-Based Awards agreements entered into between the Corporation and those executive officers in June 2013, the TSR Performance Shares may vest commencing December 31, 2014, with the number of TSR Performance Shares scheduled to be granted annually over the next four years.  The vesting of each tranche of TSR Performance Shares is subject to the attainment at each performance period end of a minimum stock price and either an absolute TSR target or a relative TSR target (the “TSR Performance Targets”) in comparison to a selection of Peer Group REITs, in each case as shall be fixed by the Committee for each performance period.  TSR, for purposes of the TSR-Based Performance Agreements, shall be equal to the share appreciation in the relevant period.  The Corporation granted 1,032 TSR Performance Shares in the year ended December 31, 2013, which were valued in accordance with ASC 718, Compensation - Stock Compensation, at their fair value, utilizing a Monte-Carlo simulation to estimate the probability of the vesting conditions being satisfied.  The Corporation has reserved shares of common stock under the 2004 Plan for issuance upon vesting of the TSR Performance Shares in accordance with the terms and conditions of the TSR-Based Awards.  In connection with the departure of two executive vice presidents effective March 31, 2014, the Corporation agreed to vest 357 TSR Performance Shares and to grant and accelerate the vesting of 528 TSR Performance Shares, for which the Corporation issued 45,062 shares of Common Stock on April 2, 2014.  In connection with the announcement of the departure of the Corporation’s president and chief executive officer effective May 11, 2015, the Corporation agreed to vest 675 TSR Performance Shares on the Separation Date, when it would issue 41,811 shares of common stock.  See Note 15: Commitments and Contingencies – Departure of Executive Officers.
	DEFERRED STOCK COMPENSATION PLAN FOR DIRECTORS
	The Amended and Restated Deferred Compensation Plan for Directors, which commenced January 1, 1999, allows non‑employee directors of the Corporation to elect to defer up to 100 percent of their annual retainer fee into deferred stock units.  The deferred stock units are convertible into an equal number of shares of common stock upon the directors’ termination of service from the Board of Directors or a change in control of the Corporation, as defined in the plan.  Deferred stock units are credited to each director quarterly using the closing price of the Corporation’s common stock on the applicable dividend record date for the respective quarter.  Each participating director’s account is also credited for an equivalent amount of deferred stock units based on the dividend rate for each quarter.
	During the years ended December 31, 2014,  2013 and 2012, 20,261,  22,392 and 17,834 deferred stock units were earned, respectively.  As of December 31, 2014 and 2013, there were 157,730 and 136,440 deferred stock units outstanding, respectively.
	LIMITED PARTNERS’ CAPITAL
Common Units
Certain individuals and entities own common units in the Company.  A common unit and a share of Common Stock of the Corporation have substantially the same economic characteristics in as much as they effectively share equally in the net income or loss of the Company.  Common unitholders (other than the General Partner) have the right to redeem their common units, subject to certain restrictions.  The redemption is required to be satisfied in shares of Common Stock of the General Partner, cash, or a combination thereof, calculated as follows:  one share of the General Partner’s Common Stock, or cash equal to the fair market value of a share of the General Partner’s Common Stock at the time of redemption, for each common unit.  The Company, in its sole discretion, determines the form of redemption of common units (i.e., whether a common unitholder receives Common Stock of the General Partner, cash, or any combination thereof).  If the Company elects to satisfy the redemption with shares of Common Stock of the General Partner as opposed to cash, the General Partner is obligated to issue shares of its Common Stock to the redeeming unitholder.  Regardless of the rights described above, the common unitholders may not put their units for cash to the Company or the General Partner under any circumstances.
Unit Transactions
As of December 31, 2014, 2013 and 2012, the Company had 11,083,876,  11,864,775 and 12,141,836 common units outstanding, respectively.
EARNINGS PER UNIT
Basic EPU excludes dilution and is computed by dividing net income available to common unitholders by the weighted average number of units outstanding for the period.  Diluted EPU reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock.
The following information presents the Company’s results for the years ended December 31, 2014,  2013 and 2012 in accordance with ASC 260, Earnings Per Share:  (dollars in thousands, except per unit amounts)
			Year Ended December 31,
Computation of Basic EPU			2014					2013				2012
Income (loss) from continuing operations		$	31,391				$	-89,686			$	37,566
Add: Noncontrolling interest in consolidated joint ventures			778					2,199				330
Income (loss) from continuing operations available to common unitholders			32,169					-87,487				37,896
Income from discontinued operations available to common
unitholders			-					70,628				8,703
Net income (loss) available to common unitholders		$	32,169				$	-16,859			$	46,599
Weighted average common units			99,999					99,785				99,922
Basic EPU:
Income (loss) from continuing operations available to common unitholders		$	0.32				$	-0.88			$	0.38
Income from discontinued operations available to common
unitholders			-					0.71				0.09
Net income (loss) available to common unitholders		$	0.32				$	-0.17			$	0.47
			Year Ended December 31,
Computation of Diluted EPU			2014			2013				2012
Income (loss) from continuing operations available to common unitholders		$	32,169		$	-87,487			$	37,896
Income from discontinued operations for diluted earnings
per unit			-			70,628				8,703
Net income (loss) available to common unitholders		$	32,169		$	-16,859			$	46,599
Weighted average common unit			100,041			99,785				99,996
Diluted EPU:
Income (loss) from continuing operations available to common unitholders		$	0.32		$	-0.88			$	0.38
Income from discontinued operations available to common
unitholders			-			0.71				0.09
Net income (loss) available to common unitholders		$	0.32		$	-0.17			$	0.47
The following schedule reconciles the units used in the basic EPU calculation to the units used in the diluted EPU calculation: (in thousands)
	Year Ended December 31,
	2014	2013	2012
Basic EPU units	99,999	99,785	99,922
Add:   Restricted Stock Awards	42	-	74
Diluted EPU units	100,041	99,785	99,996
Contingently issuable shares under the TSR Award plan were excluded from the denominator in 2013 because the criteria had not been met for the period.  Not included in the computations of diluted EPU were 10,000,  15,000 and 183,870 stock options as such securities were anti-dilutive during the years ended December 31, 2014,  2013 and 2012, respectively.  Unvested restricted stock outstanding as of December 31, 2014,  2013 and 2012 were 136,946, 409,294 and 134,328 shares, respectively.
Distributions declared per common unit for the years ended December 31, 2014,  2013 and 2012 was $0.75, $1.35 and $1.80 per unit, respectively.

Noncontrolling_Interests_In_Co

Noncontrolling Interests In Consolidated Joint Ventures	12 Months Ended
	Dec. 31, 2014
Noncontrolling Interests In Consolidated Joint Ventures [Abstract]
Noncontrolling Interests In Consolidated Joint Ventures	12. NONCONTROLLING INTERESTS IN CONSOLIDATED JOINT VENTURES
	The Company consolidates certain joint ventures in which it has ownership interests.  Various entities and/or individuals hold noncontrolling interests in these ventures.
	PARTICIPATION RIGHTS
	The Company’s interests in certain real estate projects (three properties and a future development) each provide for the initial distributions of net cash flow solely to the Company, and thereafter, other parties have participation rights (“Participation Rights”) in 50 percent of the excess net cash flow remaining after the distribution to the Company of the aggregate amount equal to the sum of: (a) the Company’s capital contributions, plus (b) an IRR of 10 percent per annum.

Employee_Benefit_401k_Plans_An

Employee Benefit 401(k) Plans And Deferred Retirement Compensation Agreements	12 Months Ended
	Dec. 31, 2014
Employee Benefit 401(k) Plans And Deferred Retirement Compensation Agreements [Abstract]
Employee Benefit 401(k) Plans And Deferred Retirement Compensation Agreements	13.EMPLOYEE BENEFIT 401(k) PLANS AND DEFERRED RETIREMENT COMPENSATION AGREEMENTS
	Employees of the Corporation, who meet certain minimum age and service requirements, are eligible to participate in the Mack-Cali Realty Corporation 401(k) Savings/Retirement Plan (the “401(k) Plan”).  Eligible employees may elect to defer from one percent up to 60 percent of their annual compensation on a pre-tax basis to the 401(k) Plan, subject to certain limitations imposed by federal law.  The amounts contributed by employees are immediately vested and non-forfeitable.  The Corporation may make discretionary matching or profit sharing contributions to the 401(k) Plan on behalf of eligible participants in any plan year.  Participants are always 100 percent vested in their pre-tax contributions and will begin vesting in any matching or profit sharing contributions made on their behalf after two years of service with the Corporation at a rate of 20 percent per year, becoming 100 percent vested after a total of six years of service with the Corporation.  All contributions are allocated as a percentage of compensation of the eligible participants for the Plan year.  The assets of the 401(k) Plan are held in trust and a separate account is established for each participant.  A participant may receive a distribution of his or her vested account balance in the 401(k) Plan in a single sum or in installment payments upon his or her termination of service with the Corporation.  Total expense recognized by the Company for the 401(k) Plan for the years ended December 31, 2014,  2013 and 2012 was zero,  $117,000 and $7,000,  respectively.
	On September 12, 2012, the Board of Directors of the Corporation approved multi-year deferred retirement compensation agreements for those executive officers in place on such date (the “Deferred Retirement Compensation Agreements”).  Pursuant to the Deferred Retirement Compensation Agreements, the Corporation was to make annual contributions of stock units (“Stock Units”) representing shares of the Corporation’s common stock on January 1 of each year from 2013 through 2017 into a deferred compensation account maintained on behalf of each Messrs. Hersh, Lefkowitz and Thomas.  In connection with Messrs. Lefkowitz and Thomas’ separation from service to the Corporation effective March 31, 2014, the Company agreed to make cash payments totaling $1.2 million for all vested and unvested Stock Units and future cash contributions pursuant to their respective Deferred Retirement Compensation Agreements (see Note 15: Commitments and Contingencies – Departure of Executive Officers).  The annual contribution for Mr. Hersh was in an amount of Stock Units equal to $500,000.  Vesting of each annual contribution of Stock Units was to occur on December 31 of each year, subject to continued employment.  Upon the payment of dividends on the Corporation’s common stock, Mr. Hersh was entitled to dividend equivalent payments in respect of both vested and unvested Stock Units payable in the form of additional Stock Units.  The Stock Units were to become payable to Mr. Hersh within 30 days after the earliest of any of the following triggering events: (a) Mr. Hersh’s death or disability; (b) the date of Mr. Hersh’s separation from service to the Corporation; and (c) the effective date of a change in control, in each case as such terms are defined in Mr. Hersh’s employment agreement.  Upon the occurrence of a triggering event, the Stock Units were to be paid in cash based on the closing price of the Corporation’s common stock on the date of such triggering event. In connection with the announcement of Mr. Hersh’s separation from service to the Corporation effective May 11, 2015, the Company agreed to make cash payments of $2.3 million on the separation date for all vested and unvested Stock Units and future cash contributions pursuant to his Deferred Retirement Compensation Agreement (See Note 13: Commitments and Contingencies – Departure of Executive Officers).  The Corporation granted 36,347 Stock Units, including 966 additional Stock Units on accrued dividends, in the year ended December 31, 2014.  Total expense recognized by the Company under the Deferred Retirement Compensation Agreements for the years ended December 31, 2014, 2013 and 2012 was $2,957,000, $595,000 and zero, respectively.  See Note 15: Commitments and Contingencies – Departure of Executive Officers related to the amount for the year ended December 31, 2014.

Disclosure_Of_Fair_Value_Of_Fi

Disclosure Of Fair Value Of Financial Instruments	12 Months Ended
	Dec. 31, 2014
Disclosure Of Fair Value Of Financial Instruments [Abstract]
Disclosure Of Fair Value Of Financial Instruments	14.DISCLOSURE OF FAIR VALUE OF FINANCIAL INSTRUMENTS
	The following disclosure of estimated fair value was determined by management using available market information and appropriate valuation methodologies.  However, considerable judgment is necessary to interpret market data and develop estimated fair value.  Accordingly, the estimates presented herein are not necessarily indicative of the amounts the Company could realize on disposition of the financial instruments at December 31, 2014 and 2013.  The use of different market assumptions and/or estimation methodologies may have a material effect on the estimated fair value amounts.
	Cash equivalents, receivables, notes receivables, accounts payable, and accrued expenses and other liabilities are carried at amounts which reasonably approximate their fair values as of December 31, 2014 and 2013.
	The fair value of the Company’s long-term debt, consisting of senior unsecured notes and mortgages, loans payable and other obligations aggregated approximately $2,133,214,000 and $2,407,802,000 as compared to the book value of approximately $2,088,654,000 and $2,362,766,000 as of December 31, 2014 and 2013, respectively.  The fair value of the Company’s long-term debt was categorized as a level 3 basis (as provided by ASC 820, Fair Value Measurements and Disclosures).  The fair value was estimated using a discounted cash flow analysis valuation based on the borrowing rates currently available to the Company for loans with similar terms and maturities.  The fair value of the mortgage debt and the unsecured notes was determined by discounting the future contractual interest and principal payments by a market rate.  Although the Company has determined that the majority of the inputs used to value its derivative financial instruments fall within level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivative financial instruments 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 derivative financial instruments. As a result, the Company has determined that its derivative financial instruments valuations in their entirety are classified in level 2 of the fair value hierarchy.
	Disclosure about fair value of financial instruments is based on pertinent information available to management as of December 31, 2014 and 2013.  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, 2014 and current estimates of fair value may differ significantly from the amounts presented herein.

Commitments_And_Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments And Contingencies [Abstract]
Commitments And Contingencies	15.COMMITMENTS AND CONTINGENCIES
	TAX ABATEMENT AGREEMENTS
	Pursuant to agreements with certain municipalities, the Company is required to make payments in lieu of property taxes (“PILOT”) on certain of its properties and has tax abatement agreements on other properties, as follows:
	The Harborside Plaza 4-A agreement with the City of Jersey City, as amended, which commenced in 2002, is for a term of 20 years.  The annual PILOT is equal to two percent of Total Project Costs, as defined.  Total Project Costs are $49.5 million.  The PILOT totaled $990,000 for each of the years ended December 31, 2014,  2013 and 2012, respectively.
	The Harborside Plaza 5 agreement, also with the City of Jersey City, as amended, which commenced in 2002, is for a term of 20 years.  The annual PILOT is equal to two percent of Total Project Costs, as defined.  Total Project Costs are $170.9 million.  The PILOT totaled $3.4 million for each of the years ended December 31, 2014,  2013 and 2012, respectively.
	The agreement with the City of Weehawken for its Port Imperial 4/5 garage development project (acquired in the Roseland Transaction) was executed in March 2011 and has a term of five years beginning when the project is substantially complete, which occurred in the third quarter 2013.  The agreement provides that real estate taxes be paid initially on the land value of the project only and allows for a phase in of real estate taxes on the value of the improvements over a five year period.
	The agreement with the City of Rahway for its Park Square multi-family rental property executed in 2009 provides that real estate taxes will be partially abated, on a declining scale, for four years from 2011 through 2015.
	At the conclusion of the above-referenced agreements, it is expected that the properties will be assessed by the municipality and be subject to real estate taxes at the then prevailing rates.
	LITIGATION
	The Company is a defendant in litigation arising in the normal course of its business activities.  Management does not believe that the ultimate resolution of these matters will have a materially adverse effect upon the Company’s financial condition taken as whole.
	GROUND LEASE AGREEMENTS
	Future minimum rental payments under the terms of all non-cancelable ground leases under which the Company is the lessee, as of December 31, 2014, are as follows: (dollars in thousands)
	Year		Amount
	2015	$	371
	2016		371
	2017		267
	2018		232
	2019		235
	2020 through 2084		15,584
	Total	$	17,060
	Ground lease expense incurred by the Company during the years ended December 31, 2014,  2013 and 2012 amounted to $406,000,  $406,000 and $406,000,  respectively.
	ROSELAND CONTINGENT CONSIDERATION
	The purchase price for the Roseland Transaction included the fair value of contingent consideration pursuant to an earn-out (“Earn Out”) agreement of approximately $10 million.  The Earn Out largely represents contingent consideration and requires the Company to pay Roseland Partners up to an aggregate maximum of $15.6 million.  The Earn Out is based on defined criteria, as follows: (i) the Roseland Assets component of up to $8.6 million for the completion of certain developments ($2.8 million), and the start of construction on others ($2.8 million), obtaining tax credits/grants on others ($3.0 million), all of which are payable over various periods of up to three years; and (ii) total return to shareholders for up to an additional $7 million, based on a total return to shareholders measured on a three year cumulative basis and on discrete years, both on an absolute basis and in comparison to a peer group.  Each of the Earn Out elements were separately valued as of the acquisition date with an aggregate fair value of contingent consideration of approximately $10 million (representing $6.3 million for the Roseland Assets and $3.7 million for the total return to shareholders component).  During the years ended December 31, 2014 and 2013, the Company recognized benefits of $1.5 million and  $2.3 million, respectively, related to a decline in fair value in the Earn Out liability, which is included in Interest and other investment income for the period. Prospectively, the Earn Out liability will be remeasured at fair value quarterly until the contingency has been resolved, with any changes in fair value representing a charge or benefit directly to earnings (with no adjustment to purchase accounting).  The measures of the Earn Out are based on significant inputs that are not observable in the market, which ASC 820 refers to as level 3 inputs.  In addition to an appropriate discount rate, the key assumption affecting the valuation for the Roseland Assets component was the probability of occurrence of the payment events under the relevant provisions (management assumed between 92 and 99 percent for completion/start criteria and 50 percent for the tax credit/grant criteria in its initial valuation).  The valuation of the TRS component includes assumptions for the risk-free rate and various other factors (i.e., stock price, dividend levels and volatility) for the Company and the relevant peer group, as defined in the Earn Out agreement.  As a result of the achievement of certain of the defined criteria, the Company paid Roseland Partners $2.8 million on January 25, 2013,  $1.4 million on March 21, 2014 and $1.4 million on September 17, 2014 related to the Roseland Assets component of the Earn Out. On July 28, 2014, the Company paid $1 million of the $3 million Earn Out related to certain tax credits/grants.  The $1 million payment had previously been at the chief executive officer’s discretion and was being accrued over the three-year period as compensation expense, and not as contingent consideration of the purchase price.  As of December 31, 2014, the balance of the Earn Out liabilities amounted to $0.9 million.  See Roseland Transaction Modifications following in this Note.
	The purchase consideration for the Roseland Transaction is subject to the return of a portion of the purchase price of up to $2.0 million upon the failure to achieve a certain level of fee revenue from the Roseland Business during the 33-month period following the closing date.  Because the fee target was highly probable, no discount was ascribed to this contingently returnable consideration.  Also, at the closing, approximately $34 million in cash of the purchase price was deposited in escrow to secure certain of the indemnification obligations of Roseland Partners and its affiliates.  In April 2013, $6.7 million of the escrow was released to Roseland Partners and on July 18, 2014, the Company agreed to release all remaining escrow funds to Roseland Partners. See Roseland Transaction Modifications following in this Note.
	DEPARTURE OF EXECUTIVE OFFICERS
	On March 3, 2014, the Company announced that Barry Lefkowitz was leaving his position as Executive Vice President and Chief Financial Officer of the Corporation effective March 31, 2014.  In connection with Mr. Lefkowitz’s departure, he received severance benefits payable pursuant to his employment agreement and outstanding equity compensation awards, including an aggregate cash payment of approximately $3.4 million, vesting of 11,457 newly issued shares of common stock of the Corporation, and vesting of 68,667 unvested shares of Restricted Stock Awards. The Company also will pay the premiums for the continuation of Mr. Lefkowitz’s existing health insurance for a period up to 48 months following March 31, 2014.
	Also on March 3, 2014, the Company announced that Roger W. Thomas was leaving his position as Executive Vice President, General Counsel and Secretary of the Corporation effective March 31, 2014.  In connection with Mr. Thomas’ departure, he received severance benefits payable pursuant to his employment agreement and outstanding equity compensation awards, including an aggregate cash payment of approximately $3.1 million, acceleration and discretionary full vesting of 33,605 newly issued shares of common stock of the Corporation, and vesting of 41,000 unvested shares of Restricted Stock Awards. The Company also will pay the premiums for the continuation of Mr. Thomas’ existing health insurance for a period of up to 48 months following September 30, 2014. Mr. Thomas served as a consultant to the Corporation from April 1, 2014 through September 30, 2014 for  an aggregate cash compensation of $300,000.
	On November 4, 2014, the Company announced that Mitchell E. Hersh will step down as President and Chief Executive Officer of the Corporation effective May 11, 2015 (the “Separation Date”) and will not stand for re-election to the Corporation’s Board of Directors (the “Board of Directors”) at the 2015 annual meeting of the Corporation’s stockholders. In connection with Mr. Hersh’s departure from the Corporation, the Corporation and Mr. Hersh entered into a Separation and General Release Agreement (the “Separation Agreement”) dated November 4, 2014 (the “Effective Date”). The Separation Agreement provides that Mr. Hersh’s employment with the Corporation is being terminated without cause, and further provides, pursuant to the terms of Mr. Hersh’s employment agreement, multi-year performance award agreement, TSR-based performance award agreement and deferred retirement compensation agreement, for (i) a cash payment to Mr. Hersh of $8 million, (ii) payment of the premiums for the continuation of Mr. Hersh’s health, dental and vision insurance for 48 months following the Separation Date, (iii) vesting of 210,000 shares of restricted common stock pursuant to Mr. Hersh’s multi-year performance award agreement, (iv) a cash payment equal to the sum of (X) $504,000, plus (Y) the product of (1) 210,000 multiplied by (2) the aggregate amount of dividends on the Corporation’s common stock that are declared and paid between the Effective Date and the Separation Date in payment of accrued but unpaid dividend equivalents pursuant to his multi-year performance award agreement, (v) issuance of 41,811 shares of common stock of the Corporation (the “Deferred Shares”) pursuant to the acceleration of vesting of 675 performance shares pursuant to Mr. Hersh’s TSR-based performance award agreement, and (vi) a cash payment of $2,311,792 pursuant to Mr. Hersh’s deferred retirement compensation award agreement. All such cash amounts and Deferred Shares will be paid to Mr. Hersh on the date that is six months and one day from the Separation Date, except in the event of death or if the payment event is due to Mr. Hersh’s disability, in which case the payments will occur shortly after such death or disability. Under the terms of the Separation Agreement, Mr. Hersh will continue to receive his base salary in accordance with his employment agreement and will continue to be eligible to participate in the Corporation’s executive incentive compensation and bonus programs. In addition, upon departure Mr. Hersh will also be entitled to receive his accrued but unpaid base salary and to have his expenses reimbursed. The Separation Agreement provides that the Separation Date may be extended at the election of the Corporation to June 30, 2015 or accelerated by Mr. Hersh for good reason, as such term is defined in the Separation Agreement.
	The Company’s total estimated costs for the pending departure of the Corporation’s Chief Executive Officer and of the departure of certain of the Corporation’s executive officers of approximately $23.8 million during the year ended December 31, 2014 was included in general and administrative expense (approximately $11.6 million was included in accounts payable, accrued expenses and other liabilities as of December 31, 2014).
	ROSELAND TRANSACTION MODIFICATIONS
	On July 18, 2014, the Company entered into separation agreements (the “Roseland Separation Agreements”) with each of Bradford R. Klatt and Carl Goldberg, formerly principals of Roseland Partners who have served as co-presidents of Roseland Management since the Company acquired the Roseland Business in October 2012.  The Separation Agreements provide that the employment agreements of Messrs. Klatt and Goldberg terminate and that they shall resign as co-presidents of Roseland Management effective October 23, 2014 (the “Roseland Separation Date”).  Also on July 18, 2014, the Company amended its purchase agreement with the sellers of the Roseland Business (the “Roseland Amendment”) to modify certain terms of the Roseland Transaction in connection with the departures of Messrs. Klatt and Goldberg.  In addition, Mr. Goldberg entered into a consulting agreement with Roseland Management (the “Consulting Agreement”) pursuant to which he shall provide consulting services for a period of one year following the Separation Date for $400,000 payable in four, equal quarterly installments.
	Pursuant to the Roseland Separation Agreements, each of Messrs. Klatt and Goldberg received a separation payment of $750,000 within five days following the Roseland Separation Date, and shall receive an additional payment of $500,000 in full satisfaction of any and all bonus payments under their respective employment agreements, which amount shall be paid six months after the date of their “separation from service” as defined in Section 409A of the Internal Revenue Code of 1986, as amended, and the Treasury Regulations and other guidance promulgated thereunder.  The Roseland Separation Agreements also contain customary mutual releases of claims and non-disparagement provisions, and Mr. Goldberg’s Consulting Agreement contains customary non-compete, confidentiality and indemnification covenants.  Mr. Goldberg’s Separation Agreement also provides that Roseland Management shall pay the premiums for the continuation of his existing health insurance for a period of one year from the Roseland Separation Date or until any earlier termination of his Consulting Agreement.
	The Roseland Amendment provides for the following material modifications to the Roseland Transaction:
	1.The non-competition covenants as they apply to Messrs. Klatt and Goldberg shall terminate on the Roseland Separation Date, and the non-competition covenants as they apply to Marshall Tycher shall be amended to permit Mr. Tycher to invest in certain future, family-controlled business ventures, subject to a right of first offer by the Company to make an investment of at least 50 percent in multi-family properties or projects covered by the right of first offer;
	2.The release to the sellers of the Roseland Business of all remaining funds held in the indemnity escrow account and the acceleration of the effectiveness of certain indemnity covenants to the Roseland Separation Date; and
	3.The payment of $1 million of the $3 million Earn Out related to certain tax credits/grants.
	The Company’s total estimated costs related to the Roseland Separation Agreements and Roseland Amendment of approximately $1.1 million in the year ended December 31, 2014 was included in general and administrative expense.  Included in accounts payable, accrued expense and other liabilities as of December 31, 2014 was $1.0 million related to the Roseland Separation Agreements and Roseland Amendment.
	OTHER
	The Company may not dispose of or distribute certain of its properties, currently comprised of seven properties with an aggregate net book value of approximately $125.3 million, which were originally contributed by certain unrelated common unitholders, without the express written consent of such common unitholders, as applicable, except in a manner which does not result in recognition of any built-in-gain (which may result in an income tax liability) or which reimburses the appropriate specific common unitholders for the tax consequences of the recognition of such built-in-gains (collectively, the “Property Lock-Ups”).  The aforementioned restrictions do not apply in the event that the Company sells all of its properties or in connection with a sale transaction which the Corporation’s Board of Directors determines is reasonably necessary to satisfy a material monetary default on any unsecured debt, judgment or liability of the Company or to cure any material monetary default on any mortgage secured by a property.  The Property Lock-Ups expire periodically through 2016.
	Upon the expiration of the Property Lock-Ups, the Company is generally required to use commercially reasonable efforts to prevent any sale, transfer or other disposition of the subject properties from resulting in the recognition of built-in gain to the specific common unitholders, which include members of the Mack Group (which includes William L. Mack, Chairman of the Corporation’s Board of Directors; David S. Mack, director of the Corporation; Earle I. Mack, a former director of the Corporation; and Mitchell E. Hersh, president, chief executive officer and director of the Corporation), the Robert Martin Group (which includes Robert F. Weinberg, a former director of the Corporation and current member of its Advisory Board), and the Cali Group (which includes John R. Cali, a former director of the Corporation and current member of its Advisory Board).  110 of the Company’s properties, with an aggregate net book value of approximately $1.3 billion, have lapsed restrictions and are subject to these conditions.
	In July 2012, the Company entered into a ground lease with Wegmans Food Markets, Inc. (“Wegmans”) at the Company’s undeveloped site located at Sylvan Way and Ridgedale Avenue in Hanover Township, New Jersey. Subject to receiving all necessary governmental approvals, Wegmans intends to construct a store of approximately 140,000 square feet on a finished pad scheduled to be completed in late 2016.  The Company expects to incur costs of approximately $25.3 million for the development of the site (of which the Company has incurred $8.0 million through December 31, 2014).

Tenant_Leases

Tenant Leases	12 Months Ended
	Dec. 31, 2014
Tenant Leases [Abstract]
Tenant Leases	16.TENANT LEASES
	The Properties are leased to tenants under operating leases with various expiration dates through 2035.  Substantially all of the commercial leases provide for annual base rents plus recoveries and escalation charges based upon the tenant’s proportionate share of and/or increases in real estate taxes and certain operating costs, as defined, and the pass‑through of charges for electrical usage.
	Future minimum rentals to be received under non-cancelable commercial operating leases at December 31, 2014 are as follows (dollars in thousands):
	Year		Amount
	2015	$	454,461
	2016		420,115
	2017		368,666
	2018		288,977
	2019		234,368
	2020 and thereafter		934,117
	Total	$	2,700,704
	Multi-family rental property residential leases are excluded from the above table as they generally expire within one year.

Segment_Reporting

Segment Reporting	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Segment Reporting	17.SEGMENT REPORTING
	The Company operates in three business segments: (i) commercial and other real estate, (ii) multi-family real estate, and (iii) multi-family services.  The Company provides leasing, property management, acquisition, development, construction and tenant-related services for its commercial and other real estate and multi-family real estate portfolio.  The Company’s multi‑family services business also provides similar services for third parties.  The Company no longer considers construction services as a reportable segment as it has phased out this line of business in 2014.  The Company had no revenues from foreign countries recorded for the years ended December 31, 2014, 2013 and 2012.  The Company had no long lived assets in foreign locations as of December 31, 2014 and 2013.  The accounting policies of the segments are the same as those described in Note 2: Significant Accounting Policies, excluding depreciation and amortization.
	The Company evaluates performance based upon net operating income from the combined properties in each of its real estate segments (commercial and other, and multi-family) and from its multi-family services segment.
	Selected results of operations for the years ended December 31, 2014,  2013 and 2012, and selected asset information as of December 31, 2014 and 2013 regarding the Company’s operating segments are as follows.  Amounts for prior periods have been restated to conform to the current period segment reporting presentation: (dollars in thousands)
			Real Estate
			Commercial				Multi-family			Corporate		Total
			& Other		Multi-family		Services			& Other (d)		Company
	Total revenues:
	2014	$	585,491	$	24,971	$	30,533	(e)	$	-4,196	$	636,799
	2013		621,352		12,792		25,710	(f)		7,177		667,031
	2012		635,278		-		4,465			10,889		650,632
	Total operating and
	interest expenses (a):
	2014	$	295,416	$	12,235	$	38,377		$	138,733	$	484,761
	2013		285,755		6,482		32,415			135,963		460,615
	2012		276,700		-		5,195			146,122		428,017
	Equity in earnings (loss) of
	unconsolidated joint ventures:
	2014	$	4,236	$	-8,790	$	2,131		$	-	$	-2,423
	2013		6,280		-10,615		2,008			-		-2,327
	2012		5,564		-1,475		-			-		4,089
	Net operating income (loss) (b):
	2014	$	294,311	$	3,946	$	-5,713		$	-142,929	$	149,615
	2013		341,877		-4,305		-4,697			-128,786		204,089
	2012		364,142		-1,475		-730			-135,233		226,704
	Total assets:
	2014	$	3,636,126	$	492,362	$	11,158		$	52,601	$	4,192,247
	2013		3,886,574		377,237		10,488			241,029		4,515,328
	Total long-lived assets (c):
	2014	$	3,344,840	$	318,524	$	3,858		$	3,482	$	3,670,704
	2013		3,620,494		240,501		3,468			3,730		3,868,193
	Total investments in
	unconsolidated joint ventures:
	2014	$	81,649	$	164,912	$	907		$	-	$	247,468
	2013		53,160		127,276		693			-		181,129
	(a)Total operating and interest expenses represent the sum of: real estate taxes; utilities; operating services; direct construction costs; real estate services expenses; general and administrative and interest expense (net of interest income). All interest expense, net of interest and other investment income, (including for property-level mortgages) is excluded from segment amounts and classified in Corporate & Other for all periods.
	(b)Net operating income represents total revenues less total operating and interest expenses (as defined in Note “a”), plus equity in earnings (loss) of unconsolidated joint ventures, for the period.
	(c)Long-lived assets are comprised of net investment in rental property, unbilled rents receivable and goodwill.
	(d)Corporate & Other represents all corporate-level items (including interest and other investment income, interest expense, non-property general and administrative expense, construction services revenue and direct construction costs) as well as intercompany eliminations necessary to reconcile to consolidated Company totals.
	(e)Includes $2.3 million of fees earned for this period from the multi-family real estate segment, which are eliminated in consolidation.
	(f)Includes $2.2 million of fees earned for this period from the multi-family real estate segment, which are eliminated in consolidation.
	The following schedule reconciles net operating income to net income available to common unitholders: (dollars in thousands)
		Year  Ended December 31,
			2014		2013		2012
	Net operating income	$	149,615	$	204,089	$	226,704
	Less:
	Depreciation and amortization		-172,490		-182,766		-174,333
	Realized gains  on disposition of
	rental property, net		54,848		-		-
	Loss from early extinguishment of debt		-582		-156		-4,960
	Impairments		-		-110,853		-9,845
	Income (loss) from continuing operations		31,391		-89,686		37,566
	Discontinued operations:
	Income from discontinued operations		-		11,811		21,878
	Loss from early extinguishment of debt		-		-703		-
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		-		59,520		-13,175
	Total discontinued operations, net		-		70,628		8,703
	Net income (loss)		31,391		-19,058		46,269
	Noncontrolling interest in consolidated joint ventures		778		2,199		330
	Net income (loss) available to common unitholders	$	32,169	$	-16,859	$	46,599

Related_Party_Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2014
Related Party Transactions [Abstract]
Related Party Transactions	18.   RELATED PARTY TRANSACTIONS
	William L. Mack, Chairman of the Board of Directors of the Corporation, David S. Mack, a director of the Corporation, and Earle I. Mack, a former director of the Corporation, are the executive officers, directors and stockholders of a corporation that leases approximately 7,034 square feet on a month-to-month basis at one of the Company’s office properties.  The Company has recognized $231,000,  $226,000 and $238,000 in revenue under this lease for the years ended December 31, 2014, 2013 and 2012, respectively, and had no accounts receivable from the corporation as of December 31, 2014 and 2013.
	Certain executive officers of the Company’s Roseland subsidiary and/or their family members (“RG”) directly or indirectly hold small non controlling interests in a certain consolidated joint venture.  Additionally, the Company earned $2,401,000, $2,272,000 and $728,000 from entities in which RG has ownership interests for the years ended December 31, 2014, 2013 and 2012, respectively.

Condensed_Quarterly_Financial_

Condensed Quarterly Financial Information	12 Months Ended
	Dec. 31, 2014
Condensed Quarterly Financial Information [Abstract]
Condensed Quarterly Financial Information	19.CONDENSED QUARTERLY FINANCIAL INFORMATION (unaudited)
	The following summarizes the condensed quarterly financial information for the Company: (dollars in thousands)
	Quarter Ended 2014		31-Dec			30-Sep		30-Jun		31-Mar
	Total revenues	$	151,414		$	155,489	$	160,300	$	169,596
	Operating and other expenses		64,177			64,374		65,788		81,854
	Real estate service salaries		5,923			6,933		6,571		6,709
	General and administrative		23,950			12,665		13,673		22,881
	Depreciation and amortization		40,811			41,983		44,711		44,985
	Total expenses		134,861			125,955		130,743		156,429
	Operating Income		16,553			29,534		29,557		13,167
	Interest expense		-27,420			-27,353		-28,159		-29,946
	Interest and other investment income		1,399			908		922		386
	Equity in earnings (loss) of unconsolidated
	joint ventures		-363			-1,268		443		-1,235
	Realized gains (losses) on disposition of rental properties		-			264		54,584		-
	Loss from early extinguishment of debt		-582			-		-		-
	Total other (expense) income		-26,966			-27,449		27,790		-30,795
	Income (loss) from continuing operations		-10,413			2,085		57,347		-17,628
	Discontinued operations:
	Income (loss) from discontinued operations		-			-		-		-
	Loss from early extinguishment of debt
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		-			-		-		-
	Total discontinued operations, net		-			-		-		-
	Net income (loss)		-10,413			2,085		57,347		-17,628
	Noncontrolling interest in consolidated joint ventures		21			145		290		322
	Net income (loss) available to common unitholders	$	-10,392		$	2,230	$	57,637	$	-17,306
	Basic earnings per common unit:
	Income (loss) from continuing operations	$	-0.1		$	0.02	$	0.58	$	-0.17
	Discontinued operations		-			-		-		-
	Net income (loss) available to common unitholders	$	-0.1		$	0.02	$	0.58	$	-0.17
	Diluted earnings per common units:
	Income (loss) from continuing operations	$	-0.1		$	0.02	$	0.58	$	-0.17
	Discontinued operations		-			-		-		-
	Net income (loss) available to common unitolders	$	-0.1		$	0.02	$	0.58	$	-0.17
	Distributions declared per common unit	$	0.15		$	0.15	$	0.15	$	0.30
	Quarter Ended 2013		31-Dec			30-Sep		30-Jun		31-Mar
	Total revenues	$	165,267		$	162,505	$	168,346	$	170,913
	Operating and other expenses		67,862			64,467		58,900		63,245
	Direct construction costs		-			609		6,511		7,825
	Real estate service salaries		6,907			5,552		5,304		4,953
	General and administrative		10,447			12,151		13,111		11,973
	Depreciation and amortization		47,666			46,087		45,665		43,348
	Impairments (1)		62,153	-2		48,700		-		-
	Total expenses		195,035			177,566		129,491		131,344
	Operating Income		-29,768			-15,061		38,855		39,569
	Interest expense		-31,626			-30,936		-31,270		-29,869
	Interest and other investment income		1,616			187		1,094		6
	Equity in earnings (loss) of unconsolidated
	joint ventures		-268			-229		-80		-1,750
	Loss from early extinguishment of debt		-156			-		-		-
	Total other (expense) income		-30,434			-30,978		-30,256		-31,613
	Income (loss) from continuing operations		-60,202			-46,039		8,599		7,956
	Discontinued operations:
	Income (loss) from discontinued operations		-9			2,157		4,530		5,133
	Loss from early extinguishment of debt		-			-		-703		-
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		-1,559	-3		47,321		13,758		-
	Total discontinued operations, net		-1,568			49,478		17,585		5,133
	Net income (loss)		-61,770			3,439		26,184		13,089
	Noncontrolling interest in consolidated joint ventures		237			1,838		62		62
	Net income (loss) available to common unitholders	$	-61,533		$	5,277	$	26,246	$	13,151
	Basic earnings per common unit:
	Income (loss) from continuing operations	$	-0.6		$	-0.45	$	0.09	$	0.08
Discontinued operations		-0.02			0.50		0.17		0.05
Net income (loss) available to common unitholders	$	-0.62		$	0.05	$	0.26	$	0.13
Diluted earnings per common unit:
Income (loss) from continuing operations	$	-0.6		$	-0.45	$	0.09	$	0.08
Discontinued operations		-0.02			0.50		0.17		0.05
Net income (loss) available to common unitholders	$	-0.62		$	0.05	$	0.26	$	0.13
Distributions declared per common unit	$	0.30		$	0.30	$	0.30	$	0.45
(1)Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions – Impairments on Properties Held and Used.
(2)During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
(3)During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.

Real_Estate_Investments_And_Ac

Real Estate Investments And Accumulated Depreciation	12 Months Ended
	Dec. 31, 2014
Real Estate Investments And Accumulated Depreciation [Abstract]
Real Estate Investments And Accumulated Depreciation
					MACK-CALI REALTY, L.P.
			REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
					31-Dec-14
					(dollars in thousands)
												SCHEDULE III
									Gross Amount at Which
								Costs	Carried at Close of
						Initial Costs		Capitalized	Period (a)
		Property	Year		Related		Building and	Subsequent		Building and		Accumulated
	Property Location	Type	Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
	NEW JERSEY
	Bergen County
	Fort Lee
	One Bridge Plaza	Office	1981	1996	-	2,439	24,462	7,701	2,439	32,163	34,602	14,550
	2115 Linwood Avenue	Office	1981	1998	-	474	4,419	5,870	474	10,289	10,763	3,629
	Lyndhurst
	210 Clay Avenue	Office	1978	2009	13,330	2,300	11,189	-9,034	781	3,674	4,455	771
	Montvale
	135 Chestnut Ridge Road	Office	1981	1997	-	2,587	10,350	1,783	2,588	12,132	14,720	5,104
	Paramus
	15 East Midland Avenue	Office	1988	1997	12,615	10,375	41,497	2,388	10,374	43,886	54,260	18,222
	140 East Ridgewood Avenue	Office	1981	1997	11,887	7,932	31,463	7,012	7,932	38,475	46,407	16,309
	461 From Road	Office	1988	1997	-	13,194	52,778	4,233	13,194	57,011	70,205	22,956
	650 From Road	Office	1978	1997	22,804	10,487	41,949	7,984	10,487	49,933	60,420	20,867
	61 South Paramus Road   (c)	Office	1985	1997	22,319	9,005	36,018	7,913	9,005	43,931	52,936	19,029
	Rochelle Park
	120 West Passaic Street	Office	1972	1997	-	1,354	5,415	431	1,357	5,843	7,200	2,424
	365 West Passaic Street	Office	1976	1997	11,887	4,148	16,592	4,442	4,148	21,034	25,182	9,216
	395 West Passaic Street	Office	1979	2006	-	2,550	17,131	437	2,550	17,568	20,118	3,717
	Upper Saddle River
	1 Lake Street	Office	1994	1997	40,756	13,952	55,812	-37,797	6,268	25,699	31,967	10,336
	10 Mountainview Road	Office	1986	1998	-	4,240	20,485	4,480	4,240	24,965	29,205	10,456
	Woodcliff Lake
	400 Chestnut Ridge Road	Office	1982	1997	-	4,201	16,802	-6,650	2,312	12,041	14,353	6,431
	50 Tice Boulevard	Office	1984	1994	23,289	4,500	-	26,578	4,500	26,578	31,078	18,326
	300 Tice Boulevard	Office	1991	1996	-	5,424	29,688	5,970	5,424	35,658	41,082	15,466
	Burlington County
	Burlington
	3 Terri Lane	Office/Flex	1991	1998	-	652	3,433	1,537	658	4,964	5,622	2,110
	5 Terri Lane	Office/Flex	1992	1998	-	564	3,792	2,444	569	6,231	6,800	2,784
	Moorestown
	2 Commerce Drive	Office/Flex	1986	1999	-	723	2,893	544	723	3,437	4,160	1,351
	101 Commerce Drive	Office/Flex	1988	1998	-	422	3,528	436	426	3,960	4,386	1,782
	102 Commerce Drive	Office/Flex	1987	1999	-	389	1,554	556	389	2,110	2,499	750
	201 Commerce Drive	Office/Flex	1986	1998	-	254	1,694	329	258	2,019	2,277	850
	202 Commerce Drive	Office/Flex	1988	1999	-	490	1,963	384	490	2,347	2,837	851
	1 Executive Drive	Office/Flex	1989	1998	-	226	1,453	739	228	2,190	2,418	873
	2 Executive Drive	Office/Flex	1988	2000	-	801	3,206	707	801	3,913	4,714	1,360
	101 Executive Drive	Office/Flex	1990	1998	-	241	2,262	807	244	3,066	3,310	1,332
	102 Executive Drive	Office/Flex	1990	1998	-	353	3,607	420	357	4,023	4,380	1,701
	225 Executive Drive	Office/Flex	1990	1998	-	323	2,477	693	326	3,167	3,493	1,436
	97 Foster Road	Office/Flex	1982	1998	-	208	1,382	389	211	1,768	1,979	823
	1507 Lancer Drive	Office/Flex	1995	1998	-	119	1,106	209	120	1,314	1,434	561
	1245 North Church Street	Office/Flex	1998	2001	-	691	2,810	83	691	2,893	3,584	997
	1247 North Church Street	Office/Flex	1998	2001	-	805	3,269	117	805	3,386	4,191	1,172
					MACK-CALI REALTY, L.P.
			REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
					31-Dec-14
					(dollars in thousands)
												SCHEDULE III
									Gross Amount at Which
								Costs	Carried at Close of
						Initial Costs		Capitalized	Period (a)
		Year		Related		Building and	Subsequent		Building and		Accumulated
Property Location		Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
1256 North Church Street	Office/Flex	1984	1998	-	354	3,098	658	357	3,753	4,110	1,542
840 North Lenola Road	Office/Flex	1995	1998	-	329	2,366	246	333	2,608	2,941	1,206
844 North Lenola Road	Office/Flex	1995	1998	-	239	1,714	298	241	2,010	2,251	881
915 North Lenola Road	Office/Flex	1998	2000	-	508	2,034	273	508	2,307	2,815	980
2 Twosome Drive	Office/Flex	2000	2001	-	701	2,807	64	701	2,871	3,572	992
30 Twosome Drive	Office/Flex	1997	1998	-	234	1,954	408	236	2,360	2,596	1,156
31 Twosome Drive	Office/Flex	1998	2001	-	815	3,276	145	815	3,421	4,236	1,211
40 Twosome Drive	Office/Flex	1996	1998	-	297	2,393	220	301	2,609	2,910	1,156
41 Twosome Drive	Office/Flex	1998	2001	-	605	2,459	178	605	2,637	3,242	923
50 Twosome Drive	Office/Flex	1997	1998	-	301	2,330	98	304	2,425	2,729	1,065
Gloucester County
West Deptford
1451 Metropolitan Drive	Office/Flex	1996	1998	-	203	1,189	74	206	1,260	1,466	534
Essex County
Millburn
150 J.F. Kennedy Parkway	Office	1980	1997	-	12,606	50,425	8,846	12,606	59,271	71,877	24,979
Roseland
4 Becker Farm Road	Office	1983	2009	39,421	5,600	38,285	-9,054	4,271	30,560	34,831	5,854
5 Becker Farm Road	Office	1982	2009	13,867	2,400	11,885	-5,626	1,492	7,167	8,659	1,128
6 Becker Farm Road	Office	1983	2009	14,226	2,600	15,548	-4,667	1,883	11,598	13,481	2,113
101 Eisenhower Parkway	Office	1980	1994	-	228	-	21,542	228	21,542	21,770	12,971
103 Eisenhower Parkway	Office	1985	1994	-	-	-	16,519	2,300	14,219	16,519	8,961
105 Eisenhower Parkway	Office	2001	2001	-	4,430	42,898	5,289	3,835	48,782	52,617	22,007
75 Livingston Avenue	Office	1985	2009	10,888	1,900	6,312	-1,637	1,281	5,294	6,575	1,045
85 Livingston Avenue	Office	1985	2009	15,243	2,500	14,238	-6,542	1,471	8,725	10,196	1,614
Hudson County
Jersey City
Harborside Plaza 1	Office	1983	1996	-	3,923	51,013	27,926	3,923	78,939	82,862	36,168
Harborside Plaza 2	Office	1990	1996	-	17,655	101,546	21,449	12,844	127,806	140,650	54,391
Harborside Plaza 3	Office	1990	1996	-	17,655	101,878	21,116	12,843	127,806	140,649	54,391
Harborside Plaza 4A	Office	2000	2000	-	1,244	56,144	14,698	1,244	70,842	72,086	28,181
Harborside Plaza 5	Office	2002	2002	221,563	6,218	170,682	52,013	5,705	223,208	228,913	80,254
101 Hudson Street	Office	1992	2005	-	45,530	271,376	921	45,530	272,297	317,827	68,400
Weehawken
500 Avenue at Port Imperial	Other	2013	2013	36,600	13,099	56,669	-21,005	13,099	35,664	48,763	1,282
Mercer County
Hamilton Township
3 AAA Drive	Office	1981	2007	-	242	3,218	1,598	242	4,816	5,058	1,438
100 Horizon Center Boulevard	Office/Flex	1989	1995	-	205	1,676	728	323	2,286	2,609	934
200 Horizon Drive	Office/Flex	1991	1995	-	205	3,027	714	356	3,590	3,946	1,700
300 Horizon Drive	Office/Flex	1989	1995	-	379	4,355	1,188	530	5,392	5,922	2,537
500 Horizon Drive	Office/Flex	1990	1995	-	379	3,395	921	495	4,200	4,695	2,029
600 Horizon Drive	Office/Flex	2002	2002	-	-	7,549	651	685	7,515	8,200	2,270
				MACK-CALI REALTY, L.P.
		REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
				31-Dec-14
				(dollars in thousands)
											SCHEDULE III
								Gross Amount at Which
							Costs	Carried at Close of
					Initial Costs		Capitalized	Period (a)
		Year		Related		Building and	Subsequent		Building and		Accumulated
Property Location		Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
700 Horizon Drive	Office	2007	2007	-	490	43	16,572	865	16,240	17,105	3,519
2 South Gold Drive	Office	1974	2007	-	476	3,487	839	476	4,326	4,802	813
Princeton
103 Carnegie Center	Office	1984	1996	-	2,566	7,868	3,183	2,566	11,051	13,617	5,072
2 Independence Way	Office	1985	2009	-	1,300	7,246	126	1,300	7,372	8,672	1,392
3 Independence Way	Office	1983	1997	-	1,997	11,391	4,186	1,997	15,577	17,574	6,986
100 Overlook Center	Office	1988	1997	-	2,378	21,754	3,384	2,378	25,138	27,516	10,295
5 Vaughn Drive	Office	1987	1995	-	657	9,800	3,001	657	12,801	13,458	6,434
Middlesex County
East Brunswick
377 Summerhill Road	Office	1977	1997	-	649	2,594	412	649	3,006	3,655	1,355
Edison
343 Thornall Street	Office	1991	2006	-	6,027	39,101	3,302	6,027	42,403	48,430	10,907
New Brunswick
Richmond Court	Multi-Family	1997	2013	-	2,992	13,534	50	2,992	13,584	16,576	350
Riverwatch Commons	Multi-Family	1995	2013	-	4,169	18,974	59	4,169	19,033	23,202	491
Plainsboro
500 College Road East (c)	Office	1984	1998	-	614	20,626	6,178	614	26,804	27,418	11,800
Woodbridge
581 Main Street	Office	1991	1997	-	3,237	12,949	26,205	8,115	34,276	42,391	15,447
Monmouth County
Freehold
2 Paragon Way	Office	1989	2005	-	999	4,619	876	999	5,495	6,494	1,567
3 Paragon Way	Office	1991	2005	-	1,423	6,041	1,550	1,423	7,591	9,014	2,235
4 Paragon Way	Office	2002	2005	-	1,961	8,827	-512	1,961	8,315	10,276	1,958
100 Willow Brook Road	Office	1988	2005	-	1,264	5,573	804	1,264	6,377	7,641	1,844
Holmdel
23 Main Street	Office	1977	2005	29,210	4,336	19,544	9,133	4,336	28,677	33,013	11,514
Middletown
One River Center, Building 1	Office	1983	2004	10,879	3,070	17,414	3,881	2,451	21,914	24,365	7,051
One River Center, Building 2	Office	1983	2004	12,204	2,468	15,043	3,702	2,452	18,761	21,213	4,628
One River Center, Building 3	Office	1984	2004	19,393	4,051	24,790	6,030	4,627	30,244	34,871	8,503
Neptune
3600 Route 66	Office	1989	1995	-	1,098	18,146	10,455	1,098	28,601	29,699	10,121
Wall Township
1305 Campus Parkway	Office	1988	1995	-	335	2,560	648	291	3,252	3,543	1,463
1325 Campus Parkway	Office/Flex	1988	1995	-	270	2,928	725	270	3,653	3,923	1,749
1340 Campus Parkway	Office/Flex	1992	1995	-	489	4,621	1,817	489	6,438	6,927	3,169
1345 Campus Parkway	Office/Flex	1995	1997	-	1,023	5,703	1,703	1,024	7,405	8,429	3,526
1350 Campus Parkway	Office	1990	1995	-	454	7,134	823	454	7,957	8,411	3,805
1433 Highway 34	Office/Flex	1985	1995	-	889	4,321	1,617	889	5,938	6,827	2,670
				MACK-CALI REALTY, L.P.
		REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
				31-Dec-14
				(dollars in thousands)
											SCHEDULE III
								Gross Amount at Which
							Costs	Carried at Close of
					Initial Costs		Capitalized	Period (a)
		Year		Related		Building and	Subsequent		Building and		Accumulated
Property Location		Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
1320 Wyckoff Avenue	Office/Flex	1986	1995	-	255	1,285	291	216	1,615	1,831	833
1324 Wyckoff Avenue	Office/Flex	1987	1995	-	230	1,439	284	190	1,763	1,953	777
Morris County
Florham Park
325 Columbia Parkway	Office	1987	1994	-	1,564	-	17,390	1,564	17,390	18,954	10,299
Morris Plains
250 Johnson Road	Office	1977	1997	-	2,004	8,016	-4,825	930	4,265	5,195	1,618
201 Littleton Road	Office	1979	1997	-	2,407	9,627	3,505	2,407	13,132	15,539	5,265
Parsippany
4 Campus Drive	Office	1983	2001	-	5,213	20,984	3,389	5,213	24,373	29,586	8,918
6 Campus Drive	Office	1983	2001	-	4,411	17,796	3,287	4,411	21,083	25,494	7,867
7 Campus Drive	Office	1982	1998	-	1,932	27,788	6,310	1,932	34,098	36,030	14,566
8 Campus Drive	Office	1987	1998	-	1,865	35,456	4,789	1,865	40,245	42,110	15,971
9 Campus Drive	Office	1983	2001	-	3,277	11,796	16,318	5,842	25,549	31,391	9,647
4 Century Drive	Office	1981	2004	-	1,787	9,575	1,862	1,787	11,437	13,224	3,461
5 Century Drive	Office	1981	2004	-	1,762	9,341	2,390	1,762	11,731	13,493	3,616
6 Century Drive	Office	1981	2004	-	1,289	6,848	2,178	1,289	9,026	10,315	2,855
2 Dryden Way	Office	1990	1998	-	778	420	110	778	530	1,308	245
4 Gatehall Drive	Office	1988	2000	-	8,452	33,929	4,433	8,452	38,362	46,814	14,754
2 Hilton Court	Office	1991	1998	-	1,971	32,007	4,958	1,971	36,965	38,936	16,047
1633 Littleton Road	Office	1978	2002	-	2,283	9,550	163	2,355	9,641	11,996	4,227
600 Parsippany Road	Office	1978	1994	-	1,257	5,594	3,277	1,257	8,871	10,128	4,515
1 Sylvan Way	Office	1989	1998	-	1,689	24,699	2,826	1,021	28,193	29,214	12,489
4 Sylvan Way	Office	1983	2009	14,575	2,400	13,486	-8,399	1,131	6,356	7,487	1,149
5 Sylvan Way	Office	1989	1998	-	1,160	25,214	2,723	1,161	27,936	29,097	11,307
7 Sylvan Way	Office	1987	1998	-	2,084	26,083	841	2,084	26,924	29,008	11,063
14 Sylvan Way	Office	2013	2013	-	13,049	26,841	8,540	13,049	35,381	48,430	1,841
20 Waterview Boulevard	Office	1988	2009	24,678	4,500	27,246	-1,233	4,208	26,305	30,513	4,736
35 Waterview Boulevard	Office	1990	2006	-	5,133	28,059	887	5,133	28,946	34,079	7,304
5 Wood Hollow Road	Office	1979	2004	-	5,302	26,488	16,441	5,302	42,929	48,231	15,710
Passaic County
Totowa
1 Center Court	Office/Flex	1999	1999	-	270	1,824	493	270	2,317	2,587	897
2 Center Court	Office/Flex	1998	1998	-	191	-	2,646	191	2,646	2,837	1,037
11 Commerce Way	Office/Flex	1989	1995	-	586	2,986	1,000	586	3,986	4,572	1,879
20 Commerce Way	Office/Flex	1992	1995	-	516	3,108	111	516	3,219	3,735	1,514
29 Commerce Way	Office/Flex	1990	1995	-	586	3,092	858	586	3,950	4,536	1,642
40 Commerce Way	Office/Flex	1987	1995	-	516	3,260	1,510	516	4,770	5,286	2,058
45 Commerce Way	Office/Flex	1992	1995	-	536	3,379	576	536	3,955	4,491	2,023
60 Commerce Way	Office/Flex	1988	1995	-	526	3,257	635	526	3,892	4,418	2,027
80 Commerce Way	Office/Flex	1996	1996	-	227	-	1,357	227	1,357	1,584	597
100 Commerce Way	Office/Flex	1996	1996	-	226	-	1,356	226	1,356	1,582	596
120 Commerce Way	Office/Flex	1994	1995	-	228	-	1,290	229	1,289	1,518	617
140 Commerce Way	Office/Flex	1994	1995	-	229	-	1,288	228	1,289	1,517	617
999 Riverview Drive	Office	1988	1995	-	476	6,024	2,793	1,102	8,191	9,293	4,018
				MACK-CALI REALTY, L.P.
		REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
				31-Dec-14
				(dollars in thousands)
											SCHEDULE III
								Gross Amount at Which
							Costs	Carried at Close of
					Initial Costs		Capitalized	Period (a)
		Year		Related		Building and	Subsequent		Building and		Accumulated
Property Location		Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
Somerset County
Basking Ridge
222 Mt. Airy Road	Office	1986	1996	-	775	3,636	2,278	775	5,914	6,689	2,662
233 Mt. Airy Road	Office	1987	1996	-	1,034	5,033	2,204	1,034	7,237	8,271	2,737
Bridgewater
440 Route 22 East	Office	1990	2010	-	3,986	13,658	4,814	3,986	18,472	22,458	3,661
721 Route 202/206	Office	1989	1997	-	6,730	26,919	9,711	6,730	36,630	43,360	18,700
Warren
10 Independence Boulevard	Office	1988	2009	16,924	2,300	15,499	-6,031	1,482	10,286	11,768	1,573
Union County
Clark
100 Walnut Avenue	Office	1985	1994	18,542	-	-	17,640	1,822	15,818	17,640	10,340
Cranford
6 Commerce Drive	Office	1973	1994	-	250	-	1,784	250	1,784	2,034	712
11 Commerce Drive	Office	1981	1994	-	470	-	5,556	470	5,556	6,026	4,655
12 Commerce Drive	Office	1967	1997	-	887	3,549	1,543	887	5,092	5,979	2,354
14 Commerce Drive	Office	1971	2003	-	1,283	6,344	1,043	1,283	7,387	8,670	2,185
20 Commerce Drive	Office	1990	1994	-	2,346	-	21,447	2,346	21,447	23,793	11,154
25 Commerce Drive	Office	1971	2002	-	1,520	6,186	1,028	1,520	7,214	8,734	3,132
65 Jackson Drive	Office	1984	1994	-	541	-	6,223	542	6,222	6,764	4,100
New Providence
890 Mountain Road	Office	1977	1997	-	2,796	11,185	6,167	3,765	16,383	20,148	6,843
Rahway
Park Square	Multi-Family	2011	2013	27,500	4,000	40,670	21	4,000	40,691	44,691	1,132
NEW YORK
New York County
New York
125 Broad Street	Office	1970	2007	-	50,191	207,002	48,289	50,191	255,291	305,482	48,103
Westchester County
Elmsford
11 Clearbrook Road	Office/Flex	1974	1997	-	149	2,159	529	149	2,688	2,837	1,129
75 Clearbrook Road	Office/Flex	1990	1997	-	2,314	4,716	107	2,314	4,823	7,137	2,189
100 Clearbrook Road	Office	1975	1997	-	220	5,366	1,653	220	7,019	7,239	3,117
125 Clearbrook Road	Office/Flex	2002	2002	-	1,055	3,676	-515	1,055	3,161	4,216	947
150 Clearbrook Road	Office/Flex	1975	1997	-	497	7,030	2,211	497	9,241	9,738	3,820
175 Clearbrook Road	Office/Flex	1973	1997	-	655	7,473	676	655	8,149	8,804	3,946
200 Clearbrook Road	Office/Flex	1974	1997	-	579	6,620	1,778	579	8,398	8,977	3,573
250 Clearbrook Road	Office/Flex	1973	1997	-	867	8,647	1,685	867	10,332	11,199	4,308
50 Executive Boulevard	Office/Flex	1969	1997	-	237	2,617	398	237	3,015	3,252	1,308
77 Executive Boulevard	Office/Flex	1977	1997	-	34	1,104	212	34	1,316	1,350	630
85 Executive Boulevard	Office/Flex	1968	1997	-	155	2,507	691	155	3,198	3,353	1,503
101 Executive Boulevard	Office	1971	1997	-	267	5,838	-3,536	101	2,468	2,569	1,060
300 Executive Boulevard	Office/Flex	1970	1997	-	460	3,609	275	460	3,884	4,344	1,680
				MACK-CALI REALTY, L.P.
		REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
				31-Dec-14
				(dollars in thousands)
											SCHEDULE III
								Gross Amount at Which
							Costs	Carried at Close of
					Initial Costs		Capitalized	Period (a)
		Year		Related		Building and	Subsequent		Building and		Accumulated
Property Location		Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
350 Executive Boulevard	Office/Flex	1970	1997	-	100	1,793	175	100	1,968	2,068	871
399 Executive Boulevard	Office/Flex	1962	1997	-	531	7,191	163	531	7,354	7,885	3,310
400 Executive Boulevard	Office/Flex	1970	1997	-	2,202	1,846	841	2,202	2,687	4,889	1,263
500 Executive Boulevard	Office/Flex	1970	1997	-	258	4,183	465	258	4,648	4,906	2,148
525 Executive Boulevard	Office/Flex	1972	1997	-	345	5,499	834	345	6,333	6,678	2,855
700 Executive Boulevard	Land Lease	N/A	1997	-	970	-	-	970	-	970	-
1 Warehouse Lane  (c)	Industrial/Warehouse	1957	1997	-	3	268	233	3	501	504	221
2 Warehouse Lane  (c)	Industrial/Warehouse	1957	1997	-	4	672	122	4	794	798	363
3 Warehouse Lane  (c)	Industrial/Warehouse	1957	1997	-	21	1,948	363	21	2,311	2,332	1,114
4 Warehouse Lane  (c)	Industrial/Warehouse	1957	1997	-	84	13,393	5,155	85	18,547	18,632	8,563
5 Warehouse Lane  (c)	Industrial/Warehouse	1957	1997	-	19	4,804	939	19	5,743	5,762	2,551
6 Warehouse Lane  (c)	Industrial/Warehouse	1982	1997	-	10	4,419	2,445	10	6,864	6,874	2,592
1 Westchester Plaza	Office/Flex	1967	1997	-	199	2,023	469	199	2,492	2,691	1,197
2 Westchester Plaza	Office/Flex	1968	1997	-	234	2,726	701	234	3,427	3,661	1,417
3 Westchester Plaza	Office/Flex	1969	1997	-	655	7,936	1,114	655	9,050	9,705	4,202
4 Westchester Plaza	Office/Flex	1969	1997	-	320	3,729	1,038	320	4,767	5,087	2,229
5 Westchester Plaza	Office/Flex	1969	1997	-	118	1,949	462	118	2,411	2,529	1,219
6 Westchester Plaza	Office/Flex	1968	1997	-	164	1,998	155	164	2,153	2,317	952
7 Westchester Plaza	Office/Flex	1972	1997	-	286	4,321	682	286	5,003	5,289	2,044
8 Westchester Plaza	Office/Flex	1971	1997	-	447	5,262	1,932	447	7,194	7,641	2,875
Hawthorne
200 Saw Mill River Road	Office/Flex	1965	1997	-	353	3,353	608	353	3,961	4,314	1,786
1 Skyline Drive	Office	1980	1997	-	66	1,711	210	66	1,921	1,987	890
2 Skyline Drive	Office	1987	1997	-	109	3,128	1,474	109	4,602	4,711	2,057
4 Skyline Drive	Office/Flex	1987	1997	-	363	7,513	2,790	363	10,303	10,666	4,874
5 Skyline Drive	Office/Flex	1980	2001	-	2,219	8,916	2,001	2,219	10,917	13,136	4,588
6 Skyline Drive	Office/Flex	1980	2001	-	740	2,971	1,044	740	4,015	4,755	2,142
7 Skyline Drive	Office	1987	1998	-	330	13,013	3,172	330	16,185	16,515	6,868
8 Skyline Drive	Office/Flex	1985	1997	-	212	4,410	951	212	5,361	5,573	2,577
10 Skyline Drive	Office/Flex	1985	1997	-	134	2,799	732	134	3,531	3,665	1,757
11 Skyline Drive  (c)	Office/Flex	1989	1997	-	-	4,788	760	-	5,548	5,548	2,252
12 Skyline Drive  (c)	Office/Flex	1999	1999	-	1,562	3,254	21	1,320	3,517	4,837	1,368
15 Skyline Drive  (c)	Office/Flex	1989	1997	-	-	7,449	628	-	8,077	8,077	3,544
17 Skyline Drive   (c)	Office	1989	1997	-	-	7,269	1,484	-	8,753	8,753	3,725
Tarrytown
230 White Plains Road	Retail	1984	1997	-	124	1,845	107	124	1,952	2,076	868
White Plains
1 Barker Avenue	Office	1975	1997	-	208	9,629	2,546	207	12,176	12,383	5,083
3 Barker Avenue	Office	1983	1997	-	122	7,864	1,781	122	9,645	9,767	4,128
50 Main Street	Office	1985	1997	-	564	48,105	14,371	564	62,476	63,040	27,557
11 Martine Avenue	Office	1987	1997	-	127	26,833	9,209	127	36,042	36,169	16,385
1 Water Street	Office	1979	1997	-	211	5,382	1,101	211	6,483	6,694	2,835
Yonkers
100 Corporate Boulevard	Office/Flex	1987	1997	-	602	9,910	1,519	602	11,429	12,031	5,126
200 Corporate Boulevard South	Office/Flex	1990	1997	-	502	7,575	1,538	502	9,113	9,615	4,107
1 Enterprise Boulevard	Land Lease	N/A	1997	-	1,379	-	1	1,380	-	1,380	-
1 Executive Boulevard	Office	1982	1997	-	1,104	11,904	3,281	1,105	15,184	16,289	6,592
				MACK-CALI REALTY, L.P.
		REAL ESTATE INVESTMENTS AND ACCUMULATED DEPRECIATION
				31-Dec-14
				(dollars in thousands)
											SCHEDULE III
								Gross Amount at Which
							Costs	Carried at Close of
					Initial Costs		Capitalized	Period (a)
		Year		Related		Building and	Subsequent		Building and		Accumulated
Property Location		Built	Acquired	Encumbrances	Land	Improvements	to Acquisition	Land	Improvements	Total	Depreciation (b)
2 Executive Boulevard	Retail	1986	1997	-	89	2,439	100	89	2,539	2,628	1,113
3 Executive Boulevard	Office	1987	1997	-	385	6,256	2,103	385	8,359	8,744	3,657
4 Executive Plaza	Office/Flex	1986	1997	-	584	6,134	942	584	7,076	7,660	3,285
6 Executive Plaza	Office/Flex	1987	1997	-	546	7,246	2,146	546	9,392	9,938	3,882
1 Odell Plaza	Office/Flex	1980	1997	-	1,206	6,815	2,353	1,206	9,168	10,374	3,895
3 Odell Plaza	Office	1984	2003	-	1,322	4,777	2,321	1,322	7,098	8,420	3,019
5 Odell Plaza	Office/Flex	1983	1997	-	331	2,988	894	331	3,882	4,213	1,994
7 Odell Plaza	Office/Flex	1984	1997	-	419	4,418	1,045	419	5,463	5,882	2,281
CONNECTICUT
Fairfield County
Stamford
419 West Avenue	Office/Flex	1986	1997	-	4,538	9,246	1,295	4,538	10,541	15,079	4,956
500 West Avenue	Office/Flex	1988	1997	-	415	1,679	615	415	2,294	2,709	818
550 West Avenue	Office/Flex	1990	1997	-	1,975	3,856	185	1,975	4,041	6,016	1,846
600 West Avenue	Office/Flex	1999	1999	-	2,305	2,863	866	2,305	3,729	6,034	1,445
650 West Avenue	Office/Flex	1998	1998	-	1,328	-	3,503	1,328	3,503	4,831	1,438
DISTRICT OF COLUMBIA
Washington,
1201 Connecticut Avenue, NW	Office	1940	1999	-	14,228	18,571	5,846	14,228	24,417	38,645	10,322
1400 L Street, NW	Office	1987	1998	-	13,054	27,423	7,909	13,054	35,332	48,386	17,571
MARYLAND
Prince George’s County
Greenbelt
Capital Office Park Parcel A	Land	N/A	2009	-	840	-	7	847	-	847	-
9200 Edmonston Road	Office	1973/03	2006	3,951	1,547	4,131	-2,484	610	2,584	3,194	1,336
6301 Ivy Lane	Office	1979/95	2006	-	5,168	14,706	1,289	5,168	15,995	21,163	3,981
6303 Ivy Lane	Office	1980/03	2006	-	5,115	13,860	770	5,115	14,630	19,745	4,236
6305 Ivy Lane	Office	1982/95	2006	-	5,615	14,420	1,071	5,615	15,491	21,106	3,835
6404 Ivy Lane	Office	1987	2006	-	7,578	20,785	1,998	7,578	22,783	30,361	6,684
6406 Ivy Lane	Office	1991	2006	-	7,514	21,152	5,770	7,514	26,922	34,436	5,119
6411 Ivy Lane	Office	1984/05	2006	-	6,867	17,470	965	6,867	18,435	25,302	4,789
Lanham
4200 Parliament Place	Office	1989	1998	-	2,114	13,546	1,227	1,393	15,494	16,887	7,227
MASSACHUSETTS
Suffolk County
Revere
Alterra at Overlook Ridge IA	Multi-Family	2004	2013	-	9,042	50,671	357	9,042	51,028	60,070	2,535
Alterra at Overlook Ridge II	Multi-Family	2008	2013	-	12,055	71,409	345	12,055	71,754	83,809	3,332
Andover Place	Multi-Family	1988	2014	-	8,535	27,609	154	8,534	27,764	36,298	696
Projects Under Development
and Developable Land				68,359	174,581	182,061		174,581	182,061	356,642	3,049
Furniture, Fixtures
and Equipment				-	-	-	12,055		12,055	12,055	3,515
TOTALS				756,910	778,751	3,510,501	668,927	760,855	4,197,324	4,958,179	1,414,305
(a)The aggregate cost for federal income tax purposes at December 31, 2014 was approximately $3.2 billion.
(b)Depreciation of buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.
(c)This property is located on land leased by the Company.
MACK-CALI REALTY, L.P.
NOTE TO SCHEDULE III
Changes in rental properties and accumulated depreciation for the periods ended December 31, 2014, 2013 and 2012 are as follows: (dollars in thousands)
		2014			2013			2012
Rental Properties
Balance at beginning of year	$	5,129,933		$	5,379,436		$	5,279,770
Additions		193,005			317,994			296,079
Rental property held for sale		-			-107,205			-84,716
Properties sold		-331,181			-256,335			-34,563
Impairment charge		-			-149,030			-20,573
Retirements/disposals		-33,578			-54,927			-56,561
Balance at end of year	$	4,958,179		$	5,129,933		$	5,379,436
Accumulated Depreciation
Balance at beginning of year	$	1,400,988		$	1,478,214		$	1,409,163
Depreciation expense		143,278			155,846			157,175
Rental property held for sale		-			-35,594			-23,852
Properties sold		-96,383			-104,196			-10,026
Impairment charge		-			-38,353			2,058
Retirements/disposals		-33,578			-54,929			-56,304
Balance at end of year	$	1,414,305		$	1,400,988		$	1,478,214

Significant_Accounting_Policie1

Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2014
Significant Accounting Policies [Abstract]
Rental Property	Rental
	PropertyRental properties are stated at cost less accumulated depreciation and amortization.  Costs directly related to the acquisition, development and construction of rental properties are capitalized.  Acquisition‑related costs are expensed as incurred.  Capitalized development and construction costs include pre-construction costs essential to the development of the property, development and construction costs, interest, property taxes, insurance, salaries and other project costs incurred during the period of development.  Capitalized development and construction salaries and related costs approximated $3.1 million,  $4.4 million and $3.8 million for the years ended December 31, 2014,  2013 and 2012, respectively.   Included in total rental property is construction, tenant improvement and development in-progress of $62.8 million and $40.8 million as of December 31, 2014 and 2013, respectively.  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.  Fully-depreciated assets are removed from the accounts.
	The Company considers a construction project as substantially completed and held available for occupancy upon the substantial completion of tenant improvements, but no later than one year from cessation of major construction activity (as distinguished from activities such as routine maintenance and cleanup).  If portions of a rental project are substantially completed and occupied by tenants, or held available for occupancy, and other portions have not yet reached that stage, the substantially completed portions are accounted for as a separate project.  The Company allocates costs incurred between the portions under construction and the portions substantially completed and held available for occupancy, primarily based on a percentage of the relative square footage of each portion, and capitalizes only those costs associated with the portion under construction.
	Properties are depreciated using the straight-line method over the estimated useful lives of the assets.  The estimated useful lives are as follows:
	Leasehold interests	Remaining lease term
	Buildings and improvements	5 to 40 years
	Tenant improvements	The shorter of the term of the
		related lease or useful life
	Furniture, fixtures and equipment	5 to 10 years
	Upon acquisition of rental property, the Company estimates the fair value of acquired tangible assets, consisting of land, building and improvements, and identified intangible assets and liabilities assumed, generally consisting of the fair value of (i) above and below market leases, (ii) in-place leases and (iii) tenant relationships.  The Company allocates the purchase price to the assets acquired and liabilities assumed based on their fair values.  The Company records goodwill or a gain on bargain purchase (if any) if the net assets acquired/liabilities assumed exceed the purchase consideration of a transaction.  In estimating the fair value of the tangible and intangible assets acquired, the Company considers information obtained about each property as a result of its due diligence and marketing and leasing activities, and utilizes various valuation methods, such as estimated cash flow projections utilizing appropriate discount and capitalization rates, estimates of replacement costs net of depreciation, and available market information.  The fair value of the tangible assets of an acquired property considers the value of the property as if it were vacant.
	Above-market and below-market lease values for acquired properties are initially recorded based on the present value (using a discount rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to each in-place lease and (ii) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the remaining initial term plus the term of any below-market fixed rate renewal options for below-market leases. The capitalized above-market lease values are amortized as a reduction of base rental revenue over the remaining terms of the respective leases, and the capitalized below-market lease values are amortized as an increase to base rental revenue over the remaining initial terms plus the terms of any below-market fixed rate renewal options of the respective leases.
	Other intangible assets acquired include amounts for in-place lease values and tenant relationship values, which are based on management’s evaluation of the specific characteristics of each tenant’s lease and the Company’s overall relationship with the respective tenant.  Factors to be considered by management in its analysis of in-place lease values include an estimate of carrying costs during hypothetical expected lease-up periods considering current market conditions, and costs to execute similar leases.  In estimating carrying costs, management includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, depending on local market conditions.  In estimating costs to execute similar leases, management considers leasing commissions, legal and other related expenses.  Characteristics considered by management in valuing tenant relationships include the nature and extent of the Company’s existing business relationships with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals.  The value of in-place leases are amortized to expense over the remaining initial terms of the respective leases.  The value of tenant relationship intangibles are amortized to expense over the anticipated life of the relationships.
	On a periodic basis, management assesses whether there are any indicators that the value of the Company’s rental properties held for use may be impaired.  In addition to identifying any specific circumstances which may affect a property or properties, management considers other criteria for determining which properties may require assessment for potential impairment.  The criteria considered by management include reviewing low leased percentages, significant near-term lease expirations, recently acquired properties, current and historical operating and/or cash flow losses, near-term mortgage debt maturities or other factors that might impact the Company’s intent and ability to hold the property.  A property’s value is impaired only if management’s estimate of the aggregate future cash flows (undiscounted and without interest charges) to be generated by the property is less than the carrying value of the property.  To the extent impairment has occurred, the loss shall be measured as the excess of the carrying amount of the property over the fair value of the property.  The Company’s estimates of aggregate future cash flows expected to be generated by each property are based on a number of assumptions.  These assumptions are generally based on management’s experience in its local real estate markets and the effects of current market conditions.  The assumptions are subject to economic and market uncertainties including, among others, demand for space, competition for tenants, changes in market rental rates, and costs to operate each property.  As these factors are difficult to predict and are subject to future events that may alter management’s assumptions, the future cash flows estimated by management in its impairment analyses may not be achieved, and actual losses or impairments may be realized in the future.
Rental Property Held For Sale	Rental Property
	Held for Sale When assets are identified by management as held for sale, the Company discontinues depreciating the assets and estimates the sales price, net of selling costs, of such assets.  If, in management’s opinion, the estimated net sales price of the assets which have been identified as held for sale is less than the net book value of the assets, a valuation allowance is established.
	If circumstances arise that previously were considered unlikely and, as a result, the Company decides not to sell a property previously classified as held for sale, the property is reclassified as held and used.  A property that is reclassified is measured and recorded individually at the lower of (a) its carrying amount before the property was classified as held for sale, adjusted for any depreciation (amortization) expense that would have been recognized had the property been continuously classified as held and used, or (b) the fair value at the date of the subsequent decision not to sell.
Investments In Unconsolidated Joint Ventures	Investments in
	Unconsolidated
	Joint VenturesThe Company accounts for its investments in unconsolidated joint ventures under the equity method of accounting.  The Company applies the equity method by initially recording these investments at cost, as Investments in Unconsolidated Joint Ventures, subsequently adjusted for equity in earnings and cash contributions and distributions.  The outside basis portion of the Company’s joint ventures is amortized over the anticipated useful lives of the underlying ventures’ tangible and intangible assets acquired and liabilities assumed.  Generally, the Company would discontinue applying the equity method when the investment (and any advances) is reduced to zero and would not provide for additional losses unless the Company has guaranteed obligations of the venture or is otherwise committed to providing further financial support for the investee.  If the venture subsequently generates income, the Company only recognizes its share of such income to the extent it exceeds its share of previously unrecognized losses.
	On a periodic basis, management assesses whether there are any indicators that the value of the Company’s investments in unconsolidated joint ventures may be impaired.  An investment is impaired only if management’s estimate of the value of the investment is less than the carrying value of the investment, and such decline in value is deemed to be other than temporary.  To the extent impairment has occurred, the loss shall be measured as the excess of the carrying amount of the investment over the value of the investment.  The Company’s estimates of value for each investment (particularly in real estate joint ventures) are based on a number of assumptions that are subject to economic and market uncertainties including, among others, demand for space, competition for tenants, changes in market rental rates, and operating costs.  As these factors are difficult to predict and are subject to future events that may alter management’s assumptions, the values estimated by management in its impairment analyses may not be realized, and actual losses or impairment may be realized in the future.  See Note 4: Investments in Unconsolidated Joint Ventures.
Cash And Cash Equivalents	Cash and Cash
	EquivalentsAll highly liquid investments with a maturity of three months or less when purchased are considered to be cash equivalents.
Deferred Financing Costs	Deferred
	Financing CostsCosts incurred in obtaining financing are capitalized and amortized over the term of the related indebtedness. Amortization of such costs is included in interest expense and was $3,274,000, $3,172,000 and $2,669,000 for the years ended December 31, 2014, 2013 and 2012, respectively.  If a financing obligation is extinguished early, any unamortized deferred financing costs are written off and included in gains (loss) from early extinguishment of debt.  Such unamortized costs which were written off amounted to $12,000,  $156,000 and $593,000 for the years ended December 31, 2014, 2013 and 2012.
Deferred Leasing Costs	Deferred
	Leasing CostsCosts incurred in connection with commercial leases are capitalized and amortized on a straight-line basis over the terms of the related leases and included in depreciation and amortization.  Unamortized deferred leasing costs are charged to amortization expense upon early termination of the lease. Certain employees of the Corporation are compensated for providing leasing services to the Properties.  The portion of such compensation related to commercial leases, which is capitalized and amortized, approximated  $3,840,000,  $4,223,000 and $4,354,000 for the years ended December 31, 2014, 2013 and 2012, respectively.
Goodwill	GoodwillGoodwill represents the excess of the purchase price over the fair value of net tangible and intangible assets acquired in a business combination. Goodwill is allocated to various reporting units, as applicable.  Each of the Company’s segments consists of a reporting unit.  Goodwill is not amortized. Management performs an annual impairment test for goodwill during the fourth quarter and between annual tests, management evaluates the recoverability of goodwill whenever events or changes in circumstances indicate that the carrying amount of goodwill may not be fully recoverable.  In its impairment tests of goodwill, management first assesses qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying amount.  If based on this assessment, management determines that the fair value of the reporting unit is not less than its carrying amount, then performing the additional two-step impairment test is unnecessary. If the carrying amount of goodwill exceeds its fair value, an impairment charge is recognized. The Company determined that its goodwill was not impaired at December 31, 2014 after management performed its impairment tests.
Derivative Instruments	Derivative
	InstrumentsThe Company measures derivative instruments, including certain derivative instruments embedded in other contracts, at fair value and records them as an asset or liability, depending on the Company’s rights or obligations under the applicable derivative contract.  For derivatives designated and qualifying as fair value hedges, the changes in the fair value of both the derivative instrument and the hedged item are recorded in earnings.  For derivatives designated as cash flow hedges, the effective portions of the derivative are reported in other comprehensive income (“OCI”) and are subsequently reclassified into earnings when the hedged item affects earnings. Changes in fair value of derivative instruments not designated as hedging and ineffective portions of hedges are recognized in earnings in the affected period.
Revenue Recognition	Revenue
	RecognitionBase rental revenue is recognized on a straight-line basis over the terms of the respective leases.  Unbilled rents receivable represents the cumulative amount by which straight-line rental revenue exceeds rents currently billed in accordance with the lease agreements.
	Above-market and below-market lease values for acquired properties are initially recorded based on the present value (using a discount rate which reflects the risks associated with the leases acquired) of the difference between (i) the contractual amounts to be paid pursuant to each in-place lease and (ii) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the remaining initial term plus the term of any below-market fixed-rate renewal options for below-market leases.  The capitalized above-market lease values for acquired properties are amortized as a reduction of base rental revenue over the remaining terms of the respective leases, and the capitalized below-market lease values are amortized as an increase to base rental revenue over the remaining initial terms plus the terms of any below-market fixed-rate renewal options of the respective leases.
	Escalations and recoveries from tenants are received from tenants for certain costs as provided in the lease agreements.  These costs generally include real estate taxes, utilities, insurance, common area maintenance and other recoverable costs.  See Note 16: Tenant Leases.
	Construction services revenue includes fees earned and reimbursements received by the Company for providing construction management and general contractor services to clients.  Construction services revenue is recognized on the percentage of completion method.  Using this method, profits are recorded on the basis of our estimates of the overall profit and percentage of completion of individual contracts.  A portion of the estimated profits is accrued based upon estimates of the percentage of completion of the construction contract.  This revenue recognition method involves inherent risks relating to profit and cost estimates.
	Real estate services revenue includes property management, development and leasing commission fees and other services, and payroll and related costs reimbursed from clients.  Fee income derived from the Company’s unconsolidated joint ventures (which are capitalized by such ventures) are recognized to the extent attributable to the unaffiliated ownership interests.
	Parking income includes income from parking spaces leased to tenants and others.
	Other income includes income from tenants for additional services arranged for by the Company and income from tenants for early lease terminations.
Allowance For Doubtful Accounts	Allowance for
	Doubtful AccountsManagement performs a detailed review of amounts due from tenants to determine if an allowance for doubtful accounts is required based on factors affecting the collectability of the accounts receivable balances.  The factors considered by management in determining which individual tenant receivable balances, or aggregate receivable balances, require a collectability allowance include the age of the receivable, the tenant’s payment history, the nature of the charges, any communications regarding the charges and other related information. Management’s estimate of the allowance for doubtful accounts requires management to exercise significant judgment about the timing, frequency and severity of collection losses, which affects the allowance and net income.
Income And Other Taxes	Income and
	Other TaxesThe Company is a partnership, and, as a result, all income and losses of the partnership are allocated to the partners for inclusion in their respective tax returns.  Accordingly, no provision or benefit for income taxes has been made in the accompanying financial statements.
	As of December 31, 2014, the estimated net basis of the rental property for federal income tax purposes was lower than the net assets as reported in the Company’s financial statements by approximately $366,131,000. The Company’s taxable income for the year ended December 31, 2014 was estimated to be approximately $73,546,000 and for the years ended December 31, 2013 and 2012 was approximately $114,522,000 and $145,928,000, respectively. The differences between book income and taxable income primarily result from differences in depreciation expenses, the recording of rental income, differences in the deductibility of certain expenses for tax purposes, differences in revenue recognition and the rules for tax purposes of a property exchange.
	Certain of the Company’s corporate subsidiaries are taxable REIT subsidiaries (each a “TRS”).  In general, a TRS may perform additional services for tenants of the Company and generally may engage in any real estate or non-real estate related business (except for the operation or management of health care facilities or lodging facilities or the providing to any person, under a franchise, license or otherwise, rights to any brand name under which any lodging facility or health care facility is operated).  A TRS is subject to corporate federal income tax.  The Company has conducted business through its TRS entities for certain property management, development, construction and other related services, as well as to hold a joint venture interest in a hotel and other matters.
	As of December 31, 2014, the Company had a deferred tax asset related to its TRS activity with a balance of approximately  $14.4 million which has been fully reserved for through a valuation allowance.  If the Corporation fails to qualify as a REIT in any taxable year, the Corporation will be subject to federal income tax (including any applicable alternative minimum tax) on its taxable income at regular corporate tax rates.  The Corporation is subject to certain state and local taxes.
	Pursuant to the amended provisions related to uncertain tax provisions of ASC 740, Income Taxes, the Company recognized no material adjustments regarding its tax accounting treatment.  The Company expects to recognize interest and penalties related to uncertain tax positions, if any, as income tax expense, which is included in general and administrative expense.
	In the normal course of business, the Company or one of its subsidiaries is subject to examination by federal, state and local jurisdictions in which it operates, where applicable.  As of December 31, 2014, the tax years that remain subject to examination by the major tax jurisdictions under the statute of limitations are generally from the year 2010 forward.
Earnings Per Unit	Earnings
	Per UnitThe Company presents both basic and diluted earnings per unit (“EPU”).  Basic EPU excludes dilution and is computed by dividing net income available to common unitholders by the weighted average number of units outstanding for the period.  Diluted EPU reflects the potential dilution that could occur if securities or other contracts to issue common units were exercised or converted into common units, where such exercise or conversion would result in a lower EPU amount from continuing operations amount.  Units whose issuance is contingent upon the satisfaction of certain conditions shall be considered outstanding and included in the computation of diluted EPU as follows (i) if all necessary conditions have been satisfied by the end of the period (the events have occurred), those units shall be included as of the beginning of the period in which the conditions were satisfied (or as of the date of the grant, if later) or (ii) if all necessary conditions have not been satisfied by the end of the period, the number of contingently issuable units included in diluted EPU shall be based on the number of units, if any, that would be issuable if the end of the reporting period were the end of the contingency period (for example, the number of units that would be issuable based on current period earnings or period-end market price) and if the result would be dilutive. Those contingently issuable units shall be included in the denominator of diluted EPU as of the beginning of the period (or as of the date of the grant, if later).
Distributions Payable	Distributions
	PayableThe distributions payable at December 31, 2014 represents distributions payable to common unitholders (99,950,528 units) for all such holders of record as of January 6, 2015 with respect to the fourth quarter 2014. The fourth quarter 2014 common unit distributions of $0.15 per common unit were approved by the Corporation’s Board of Directors on December 9, 2014.  The common unit distributions payable were paid on January 14, 2015.
	The distributions payable at December 31, 2013 represents distributions payable to common unitholders (99,792,777 units), for all such holders of record as of January 6, 2014 with respect to the fourth quarter 2013.  The fourth quarter 2013 common unit distributions of $0.30 per common unit were approved by the Corporation’s Board of Directors on December 10, 2013.  The common unit distributions payable were paid on January 15, 2014.
	The Company has determined that the $0.90 distributions per common unit paid during the year ended December 31, 2014 represented approximately 77 percent ordinary income and approximately 23 percent return of capital to its unitholders; the $1.50 distributions per common unit paid during the year ended December 31, 2013 represented approximately 53 percent ordinary income, approximately 33 percent return of capital and approximately 14 percent capital gain to its unitholders; and the $1.80 distributions per common unit paid during the year ended December 31, 2012 represented approximately 75 percent ordinary income and approximately 25 percent return of capital to its unitholders.
Costs Incurred For Stock Issuances	Costs Incurred
	For Stock
	IssuancesCosts incurred in connection with the Corporation’s stock issuances are reflected as a reduction of General Partner’s capital.
Stock Compensation	Stock
	CompensationThe Company accounts for stock compensation in accordance with the provisions of ASC 718, Compensation-Stock Compensation. These provisions require that the estimated fair value of restricted stock (“Restricted Stock Awards”), total stockholder return (“TSR”) based performance shares and stock options at the grant date be amortized ratably into expense over the appropriate vesting period.  The Company recorded stock compensation expense of $8,139,000,  $2,387,000 and $3,642,000 for the years ended December 31, 2014, 2013 and 2012, respectively.  The amount for 2014 included $5,824,000 related to the departure of executive officers.  See Note 15: Commitments and Contingencies – Departure of Executive Officers.
Other Comprehensive Income	Other
	Comprehensive
	IncomeOther comprehensive income (loss) includes items that are recorded in equity, such as unrealized holding gains or losses on marketable securities available for sale.  There was no difference in other comprehensive income to net income for the years ended December 31, 2014, 2013 and 2012, and no accumulated other comprehensive income as of December 31, 2014 and 2013.
Fair Value Hierarchy	Fair Value
	HierarchyThe standard Fair Value Measurements specifies a hierarchy of valuation techniques based upon whether the inputs to those valuation techniques reflect assumptions other market participants would use based upon market data obtained from independent sources (observable inputs). The following summarizes the fair value hierarchy:
		·	Level 1: Quoted prices in active markets that are unadjusted and accessible at the measurement date for identical, unrestricted assets or liabilities;
		·	Level 2: Quoted prices for identical assets and liabilities in markets that are inactive, quoted prices for similar assets and liabilities in active markets or financial instruments for which significant inputs are observable, either directly or indirectly, such as interest rates and yield curves that are observable at commonly quoted intervals and
		·	Level 3: Prices or valuations that require inputs that are both significant to the fair value measurement and unobservable.
	In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy.  In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls has been determined 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.
Discontinued Operations	Discontinued
	Operations In April 2014, the FASB issued guidance related to the reporting of discontinued operation and disclosures of disposals of components of an entity.  This guidance defines a discontinued operation as a component or group of components disposed or classified as held for sale and represents a strategic shift that has (or will have) a major effect on an entity’s operations and final result; the guidance states that a strategic shift could include a disposal of a major geographical area of operations, a major line of business, a major equity method investment or other major parts of an entity.  The guidance also provides for additional disclosure requirements in connection with both discontinued operations and other dispositions not qualifying as discontinued operations.  The guidance will be effective for all companies for annual and interim periods beginning on or after December 15, 2014.  The guidance applies prospectively to new disposals and new classifications of disposal groups as held for sale after the effective date.  All entities may early adopt the guidance for new disposals (or new classifications as held for sale) that have not been reported in financial statements previously issued or available for issuance.    The Company has elected to early adopt this standard effective with the interim period beginning January 1, 2014.    Prior to January 1, 2014, properties identified as held for sale and/or disposed of were presented in discontinued operations for all periods presented.  See Note 7: Discontinued Operations.
Impact Of Recently Issued Accounting Standards	Impact Of
	Recently-Issued
	Accounting
	StandardsIn May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09 Revenue from Contracts with Customers (Topic 606) (“ASU 2014-09”).  ASU 2014-09 is a comprehensive new revenue recognition model requiring a company to recognize revenue to depict the transfer of goods or services to a customer at an amount reflecting the consideration it expects to receive in exchange for those goods or services.  In adopting ASU 2014-09, companies may use either a full retrospective or a modified retrospective approach.  Additionally, this guidance requires improved disclosures regarding the nature, amount, timing and uncertainty of revenue and cash flows arising from contracts with customers.  ASU 2014-09 is effective for the first interim period within annual reporting periods beginning after December 15, 2016, and early adoption is not permitted.  The Company is currently in the process of evaluating the impact the adoption of ASU 2014-09 will have on the Company’s financial position or results of operations.
	In August 2014, the FASB issued ASU 2014-15, which requires management to evaluate whether there are conditions or events that raise substantial doubt about the entity’s ability to continue as a going concern, and to provide certain disclosures when it is probable that the entity will be unable to meet its obligations as they become due within one year after the date that the financial statements are issued.  ASU 2014-15 is effective for the annual period ended December 31, 2016 and for annual periods and interim periods thereafter with early adoption permitted.  The adoption of ASU 2014-15 is not expected to materially impact the Company’s consolidated financial statements.

Significant_Accounting_Policie2

Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Significant Accounting Policies [Abstract]
Estimated Useful Lives Of Assets	Leasehold interests	Remaining lease term
	Buildings and improvements	5 to 40 years
	Tenant improvements	The shorter of the term of the
		related lease or useful life
	Furniture, fixtures and equipment	5 to 10 years

Real_Estate_Transactions_Table

Real Estate Transactions (Tables)	12 Months Ended
	Dec. 31, 2014
Real Estate Properties [Line Items]
Schedule Of Purchase Price Allocation
			Alterra			Alterra
			at Overlook			at Overlook			Park			Richmond			Riverwatch		Total
			Ridge 1A			Ridge 1B			Square			Court			Commons		Acquisitions
	Land	$	9,042		$	12,055		$	4,000		$	2,992		$	4,169	$	32,258
	Buildings and improvements		50,671			71,409			40,670			13,534			18,974		195,258
	Furniture, fixtures and equipment		801			1,474			610			177			228		3,290
	Above market leases (1)		-			-			24			-			-		24
	In-place lease values (1)		931			3,148			1,249			356			638		6,322
			61,445			88,086			46,553			17,059			24,009		237,152
	Less: Below market lease values (1)		195			136			177			36			49		593
			195			136			177			36			49		593
	Net cash paid at acquisition	$	61,250		$	87,950		$	46,376		$	17,023		$	23,960	$	236,559
	(1)In-place lease values and above/below market lease values will be amortized over one year or less.
Schedule Of Properties Acquired
	Acquisition			# of	# of			Acquisition
	Date	Property	Location	Properties	Apartment Units			Cost
	1/18/13	Alterra at Overlook Ridge 1A	Revere, Massachusetts	1	310		$	61,250	(a)
	4/4/13	Alterra at Overlook Ridge 1B	Revere, Massachusetts	1	412			87,950	(a)
	11/20/13	Park Square	Rahway, New Jersey	1	159			46,376	(b)
	12/19/13	Richmond  Ct / Riverwatch Commons	New Brunswick, New Jersey	2	200			40,983	(c)
	Total Acquisitions			5	1,081		$	236,559
	(a)The acquisition cost was funded primarily through borrowings under the Company’s unsecured revolving credit facility.
	(b)The acquisition cost consisted of $43,421,000 in cash consideration and future purchase price earn out payment obligations, subsequent to conditions related to a real estate tax appeal, recorded at fair value of $2,955,000 at closing.  $42,613,355 of the cash consideration was funded from funds held by a qualified intermediary, which were proceeds from the Company’s prior property sales.  The remaining cash consideration was funded primarily from available cash on hand.  $2,550,000 of the earn-out obligation amount was paid in January 2014, with the remaining balance of $405,000 still potentially payable in the future.
	(c)$12,701,925 of the acquisition cost was funded from funds held by a qualified intermediary, which were proceeds from the Company’s prior property sales.  The remaining acquisition cost was funded primarily from available cash on hand.
Schedule Of Net Assets Recorded Upon Consolidation
	Land		$	5,585
	Construction in progress			3,387
				8,972
	Cash and cash equivalents			79
	Other assets			47
	Accounts payable			-325
				-199
	Noncontrolling interest recorded upon consolidation			-1,252
	Net assets recorded upon consolidation		$	7,521
Schedule Of Properties Which Commenced Initial Operations
							Garage			Development				Development
					# of	Rentable	Parking			Costs Incurred				Costs Per
	Date	Property/Address	Location	Type	Bldgs.	Square Feet	Spaces			by Company				Square Foot
	6/5/13	14 Sylvan Way	Parsippany, New Jersey	Office	1	203,506	-		$	51,611	(a)		$	254
	8/1/13	Port Imperial South 4/5	Weehawken, New Jersey	Parking/Retail	1	16,736	850			50,656	(b)			N/A
	Totals				2	220,242	850		$	102,267
	(a)Development costs included approximately $13.0 million in land costs and $4.3 million in leasing costs.  Amounts are as of December 31, 2013.
	(b)Development costs included approximately $13.1 million in land costs.  Amounts are as of December 31, 2013.
Schedule Of Property Sales	The Company sold the following office properties during the year ended December 31, 2014 (dollars in thousands):
			Andover
			Place
	Land	$	8,535
	Buildings and improvements		27,609
	Furniture, fixtures and equipment		459
	In-place lease values (1)		1,118
			37,721
	Less: Below market lease values (1)		-25
	Net cash paid at acquisition	$	37,696
	(1) In-place lease values and below market lease values will be amortized over one year or less.
	The Company sold the following office properties during the year ended December 31, 2013, which were classified as discontinued operations – See Note 7: Discontinued Operations (dollars in thousands):
					Rentable			Net			Net
	Sale			# of	Square			Sales			Book			Realized
	Date	Property/Address	Location	Bldgs.	Feet			Proceeds			Value			Gain (loss)
	4/10/13	19 Skyline Drive (a)	Hawthorne, New York	1	248,400		$	16,131		$	16,005		$	126
	4/26/13	55 Corporate Drive	Bridgewater, New Jersey	1	204,057			70,967			51,308			19,659
	5/2/13	200 Riser Road	Little Ferry, New Jersey	1	286,628			31,775			14,852			16,923
	5/13/13	777 Passaic Avenue	Clifton, New Jersey	1	75,000			5,640			3,713			1,927
	5/30/13	16 and 18 Sentry Parkway West (b)	Blue Bell, Pennsylvania	2	188,103			19,041			19,721			-680
	5/31/13	51 Imclone Drive (c)	Branchburg, New Jersey	1	63,213			6,101			5,278			823
	6/28/13	40 Richards Avenue	Norwalk, Connecticut	1	145,487			15,858			17,027			-1,169
	7/10/13	106 Allen Road	Bernards Township, New Jersey	1	132,010			17,677			15,081			2,596
	8/27/13	Pennsylvania office portfolio (d) (e)	Suburban Philadelphia, Pennsylvania	15	1,663,511			207,425			164,259			43,166
	Totals			24	3,006,409		$	390,615	(f)	$	307,244		$	83,371	(g)
		(a)		The Company recognized a valuation allowance of $7.1 million on this property identified as held for sale at December 31, 2012.  In connection with the sale, the Company provided an interest-free note receivable to the buyer of $5 million (with a net present value of $3.7 million at closing) which matures in 2023 and requires monthly payments of principal.  See Note 5: Deferred charges, goodwill and other assets.
		(b)		The Company recorded an $8.4 million impairment charge on these properties at December 31, 2012.  The Company has retained a subordinated interest in these properties.
		(c)		The property was encumbered by a mortgage loan which was satisfied by the Company at the time of the sale.  The Company incurred $0.7 million in costs for the debt satisfaction, which was included in discontinued operations:  loss from early extinguishment of debt for the year ended December 31, 2013.
		(d)		In order to reduce the carrying value of five of the properties to their estimated fair market values, the Company recorded impairment charges of $23,851,000 at June 30, 2013.  The fair value used in the impairment charges was based on the purchase and sale agreement for the properties ultimately sold.
		(e)		The Company completed the sale of this office portfolio and three developable land parcels for approximately $233 million: $201 million in cash ($55.3 million of which was held by a qualified intermediary until such funds were used in acquisitions), a $10 million mortgage on one of the properties ($8 million of which was funded at closing) and subordinated equity interests in each of the properties being sold with capital accounts aggregating $22 million.  Net sale proceeds from the sale aggregated $207 million which was comprised of the $233 million gross sales price less the subordinated equity interests of $22 million and $4 million in closing costs. The purchasers of the Pennsylvania office portfolio are joint ventures formed between the Company and affiliates of the Keystone Property Group (the “Keystone Affiliates”).  The mortgage loan has a term of two years with a one year extension option and bears interest at LIBOR plus six percent.  The Company's equity interests in the joint ventures will be subordinated to Keystone Affiliates receiving a 15 percent internal rate of return (“IRR”) after which the Company will receive a ten percent IRR on its subordinated equity and then all profit will be split equally.  In connection with these partial sale transactions, because the buyer receives a preferential return, the Company only recognized profit to the extent that they received net proceeds in excess of their entire carrying value of the properties, effectively reflecting their retained subordinate equity interest at zero.  As part of the transaction, the Company has rights to own, after zoning-approval-subdivision, land at the 150 Monument Road property located in Bala Cynwyd, Pennsylvania, for a contemplated multi-family residential development.
		(f)		This amount excludes approximately $535,000 of net closing prorations and related adjustments received from sellers at closing.
		(g)		This amount, net of impairment charges recorded in 2013 of $23,851,000 on certain of the properties prior to their sale (per Note [d] above), comprises the $59,520,000 of realized gains (losses) and unrealized losses on disposition of rental property and impairments, net, for the year ended December 31, 2013.  See Note 7: Discontinued Operations.
Summary Of Income From Properties Sold
		Year Ended December 31,
			2013			2012
	Total revenues	$	33,601		$	66,882
	Operating and other expenses		-13,454			-26,484
	Depreciation and amortization		-8,218			-17,765
	Interest expense		-118			-755
	Income from discontinued operations		11,811			21,878
	Loss from early extinguishment of debt		-703			-
	Impairments (1)		-23,851			-8,400
	Unrealized losses on disposition of rental property (2)		-			-9,213
	Realized gains on disposition of rental property		83,371			4,438
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		59,520			-13,175
	Total discontinued operations, net	$	70,628		$	8,703
	(1)Represents impairment charges recorded on certain properties prior to their sale.
	(2)Represents valuation allowances on properties identified as held for sale in 2012, as follows:
		(i)		At March 31, 2012, the Company identified as held for sale its 47,700 square foot office building located at 95 Chestnut Ridge Road in Montvale, New Jersey. The Company determined that the carrying amount of this property was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $0.5 million at March 31, 2012. On July 25, 2012, the Company sold the building for approximately $4.0 million (with no gain from the sale).
		(ii)		At March 31, 2012, the Company identified as held for sale three office buildings totaling 222,258 square feet in Moorestown, New Jersey. The Company determined that the aggregate carrying amount of these properties was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $1.6 million at June 30, 2012. On November 7, 2012, the Company sold the buildings for approximately $19.4 million and recognized a loss of approximately $0.1 million from the sale.
		(iii)		At December 31, 2012, the Company identified as held for sale its 248,400 square foot office building located at 19 Skyline Drive in Hawthorne, New York. The Company determined that the carrying amount of this property was not expected to be recovered from estimated sales proceeds and accordingly recognized a valuation allowance of $7.1 million at December 31, 2012. Also at December 31, 2012, the Company identified as held for sale its 204,057 square foot office building located at 55 Corporate Drive in Bridgewater, New Jersey. The two properties held for sale at December 31, 2012 carried an aggregate book value of $60.9 million, net of accumulated depreciation of $16.8 million and a valuation allowance of $7.1 million.  As of April 10, 2013, the Company sold 19 Skyline Drive for approximately $16.1 million and recognized a gain of approximately $0.1 million.  As of April 26, 2013, the Company sold 55 Corporate Drive for approximately $71 million and recognized a gain of approximately $19.7 million.
Properties Sold, Year To Date [Member]
Real Estate Properties [Line Items]
Summary Of Income From Properties Sold
			Year Ended December 31,
				2014			2013			2012
	Total revenues		$	28,823		$	55,677		$	54,753
	Operating and other expenses			-17,248			-27,993			-25,142
	Depreciation and amortization			-6,371			-15,061			-14,522
	Interest income			4			-			-615
	Income from properties sold		$	5,208		$	12,623		$	14,474
	Impairments			-			-20,761			-
	Realized gains (losses) on sales, net			54,848			-			-
	Total income (loss) from properties sold		$	60,056		$	-8,138		$	14,474
Andover Place [Member]
Real Estate Properties [Line Items]
Schedule Of Purchase Price Allocation
			Andover
			Place
	Land	$	8,535
	Buildings and improvements		27,609
	Furniture, fixtures and equipment		459
	In-place lease values (1)		1,118
			37,721
	Less: Below market lease values (1)		-25
	Net cash paid at acquisition	$	37,696
	(1) In-place lease values and below market lease values will be amortized over one year or less.

Investments_In_Unconsolidated_1

Investments In Unconsolidated Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2014
Investments In Unconsolidated Joint Ventures [Abstract]
Summary Of Unconsolidated Joint Ventures
													Property Debt
		Number of		Company's				Carrying Amount					As of December 31, 2014
		Apartment Units		Effective				As of December 31,						Maturity	Interest
	Entity / Property Name	or Square Feet (sf)		Ownership % (a)				2014			2013		Balance	Date	Rate
	Multi-family
	Marbella RoseGarden, L.L.C./ Marbella  (b)	412	units	24.27	%		$	15,779		$	15,797	$	95,000	5/1/18	4.99	%
	RoseGarden Monaco Holdings, L.L.C./ Monaco   (b)	523	units	15.00	%			2,161			3,201		165,000	2/1/21	4.19	%
	Rosewood Lafayette Holdings, L.L.C./ Highlands at Morristown Station  (b)	217	units	25.00	%			62			857		38,665	7/1/15	4.00	%
	PruRose Port Imperial South 15, LLC /RiversEdge at Port Imperial (b)	236	units	50.00	%			-			-		57,500	9/1/20	4.32	%
	Rosewood Morristown, L.L.C. / Metropolitan at 40 Park  (c) (d)	130	units	12.50	%			6,029			6,455		46,217	(e)	(e)
	Overlook Ridge JV, L.L.C./ Quarrystone at Overlook Ridge  (b) (f)	251	units	50.00	%			-			-		69,501	(g)	(g)
	Overlook Ridge JV 2C/3B, L.L.C./The Chase at Overlook Ridge  (b) (f)	371	units	50.00	%			2,524			-		49,824	12/26/15	L+2.50	%	(h)
	PruRose Riverwalk G, L.L.C./ RiverTrace at Port Imperial   (b)	316	units	25.00	%			955			3,117		79,594	7/15/21	6.00	%	(i)
	Elmajo Urban Renewal Associates, LLC / Lincoln Harbor (Bldg A&C) (b)	355	units	7.50	%			-			203		81,264	6/27/16	L+2.10	%	(j)
	Crystal House Apartments Investors LLC / Crystal House  (k)	828	units	25.00	%			27,051			26,838		165,000	4/1/20	3.17	%
	Portside Master Company, L.L.C./ Portside at Pier One - Bldg 7  (b)	176	units	38.25	%			1,747			3,207		37,093	12/4/15	L+2.50	%	(l)
	PruRose Port Imperial South 13, LLC / RiverParc at Port Imperial  (b)	280	units	20.00	%			1,087			2,206		49,084	6/27/16	L+2.15	%	(m)
	Roseland/Port Imperial Partners, L.P./ Riverwalk C  (b) (n)	363	units	20.00	%			1,800			2,068		-	-	-
	RoseGarden Marbella South, L.L.C./ Marbella II	311	units	24.27	%			11,282			7,567		31,564	3/30/17	L+2.25	%	(o)
	Estuary Urban Renewal Unit B, LLC / Lincoln Harbor (Bldg B)  (b)	227	units	7.50	%			-			24		40,366	1/25/17	L+2.10	%	(p)
	Riverpark at Harrison I, L.L.C./ Riverpark at Harrison	141	units	36.00	%			4,744			3,655		21,298	6/27/16	L+2.35	%	(q)
	Capitol Place Mezz LLC / Station Townhouses	377	units	50.00	%			49,327			46,628		73,971	7/1/33	4.82	%	(r)
	Harborside Unit A Urban Renewal, L.L.C. / URL Harborside  (ab)	763	units	85.00	%			34,954			-		-	8/1/29	5.197	%	(aa)
	RoseGarden Monaco, L.L.C./ San Remo Land	300	potential units	41.67	%			1,283			1,224		-	-	-
	Grand Jersey Waterfront URA, L.L.C./ Liberty Landing	1,000	potential units	50.00	%			337			337		-	-	-
	Office
	Red Bank Corporate Plaza, L.L.C./ Red Bank	92,878	sf	50.00	%			3,963			4,046		15,868	5/17/16	L+3.00	%	(s)
	12 Vreeland Associates, L.L.C./ 12 Vreeland Road	139,750	sf	50.00	%			5,620			5,514		14,002	7/1/23	2.87	%
	BNES Associates III / Offices at Crystal Lake	106,345	sf	31.25	%			1,993			1,753		6,756	11/1/23	4.76	%
	Hillsborough 206 Holdings, L.L.C./ Hillsborough 206	160,000	sf	50.00	%			1,962			1,962		-	-	-
	KPG-P 100 IMW JV, LLC / 100 Independence Mall West	339,615	sf	33.33	%			-			1,887		61,500	9/9/16	L+7.00	%	(t)
	Keystone-Penn	1,842,820	sf	(u)				-			-		203,811	(v)	(v)
	Keystone-TriState	1,266,384	sf	(w)				6,140			-		204,843	(x)	(x)
	KPG-MCG Curtis JV, L.L.C./ Curtis Center  (ac)	885,000	sf	50.00	%			59,911			-		(ae)	(ae)	(ae)
	Other
	Plaza VIII & IX Associates, L.L.C./ Vacant land (parking operations)	1,225,000	sf	50.00	%			4,022			3,702		-	-	-
	Roseland/North Retail, L.L.C./ Riverwalk at Port Imperial  (b)	30,745	sf	20.00	%			1,828			1,930		-	-	-
	South Pier at Harborside / Hyatt Regency Jersey City on the Hudson	350	rooms	50.00	%			(af)			(af)		65,643	(y)	(y)
	Stamford SM LLC / Senior Mezzanine Loan  (z)	n/a	n/a	80.00	%			-			36,258		-	-	-
	Other (ad)							907			693		-	-	-
	Totals:						$	247,468		$	181,129	$	1,673,364
		(a)		Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
		(b)		The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the Company is not expected to meaningfully participate in the venture's cash flows in the near term.
		(c)		Through the joint venture, the Company also owns a 12.5 percent interest in a 50,973 square feet retail building ("Shops at 40 Park") and a 25 percent interest in a to-be-built 59-unit, five story multi-family rental development property ("Lofts at 40 Park").
		(d)		The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the payment of the outstanding balance remaining on a note ($975 as of December 31, 2014), and is not expected to meaningfully participate in the venture's cash flows in the near term.
		(e)		Property debt balance consists of: (i) a loan, collateralized by the Metropolitan at 40 Park, with a balance of $38,600 at December 31, 2014, bears interest at 3.25 percent, matures in September 2020 and is interest only through September 2015; (ii) a loan, collateralized by the Shops at 40 Park, with a balance of $6,500 at December 31, 2014, bears interest at 3.63 percent, matures in August 2018 and is interest-only through July 2015; and (iii) a loan, collateralized by the Lofts at 40 Park, with a balance of $1,117, bears interest at LIBOR plus 250 basis points and matures in September 2015.  The Shops at 40 Park mortgage loan also provides for additional borrowing proceeds of $1 million based on certain preferred thresholds being achieved.
		(f)		On August 15, 2014, the Company acquired the equity interests of its joint venture partner in Overlook Ridge JV 2C/3B, L.L.C. for $2.97 million and LR Overlook Phase II, L.L.C., the property-owning entity owned by Overlook Ridge JV, L.L.C., which increased its ownership to 50 percent in two  operating multi-family properties.  The Company also acquired the equity interests of its joint venture partner in LR Overlook Phase III, L.L.C. and  Overlook Ridge, L.L.C. for $0.6 million and $12.99 million respectively, which increased its ownership to 100 percent in developable land (See Note 3: Real Estate Transactions – Acquisitions).
		(g)		Property debt balance consists of: (i) the senior loan, collateralized by the Quarrystone property, with a balance of $52,501 at December 31, 2014, bears interest at LIBOR plus 200 basis, matures in March 2016   and (ii) the junior loan, with a balance of $17,000, bears interest at LIBOR plus 90 basis points, matures in March 2016 and is collateralized by a $17,000 letter of credit provided by an affiliate of the partner.
		(h)		The construction loan has a maximum borrowing amount of $55,500 and provides, subject to certain conditions, two one-year extension options with a fee of 25 basis points each.  The joint venture has a swap agreement that fixes the all-in rate to 3.0875 percent per annum on an initial notional amount of $1,840, increasing to $52,000, for the period from September 3, 2013 to November 2, 2015.
		(i)		The construction loan with a maximum borrowing amount of $83,113 was converted to a permanent loan on December 26,2014 with a maximum borrowing amount of $80,249
		(j)		The construction loan has a maximum borrowing amount of $91,000 and provides, subject to certain conditions, a one-year extension option with a fee of 25 basis points.
		(k)		The Company also owns a 50 percent interest in a vacant land parcel to accommodate the development of approximately 295 additional units of which 252 are currently approved.
		(l)		The construction loan has a maximum borrowing amount of $42,500 and provides, subject to certain conditions, two two-year extension options with a fee of 12.5 basis points for the first two-year extension and 25 basis points for the second two-year extension.
		(m)		The construction loan has a maximum borrowing amount of $73,350 and provides, subject to certain conditions, one-year extension option followed by a six-month extension option with a fee of 25 basis points each. The joint venture has a swap agreement that fixes the all-in rate to 2.79 percent per annum on an initial notional amount of $1,620, increasing to $69,500 for the period from July 1, 2013 to January 1, 2016.
		(n)		The Company also owns a 20 percent residual interest in undeveloped land parcels: parcels 6, I, and J ("Port Imperial North Land") that can accommodate the development of 836 apartment units.
		(o)		The construction loan has a maximum borrowing amount of $77,400 and provides, subject to certain conditions, two one-year extension options with a fee of 25 basis points for each year.
		(p)		The construction loan has a maximum borrowing amount of $57,000 and provides, subject to certain conditions, a one-year extension option with a fee of 25 basis points.
		(q)		The construction loan has a maximum borrowing amount of $23,400 and provides, subject to certain conditions, two one-year extension options with a fee of 20 basis points for each year.
		(r)		The construction/permanent  loan has a maximum borrowing amount of $100,700 with amortization starting in August 2017.
		(s)		The joint venture has a swap agreement that fixes the all-in rate to 3.99375 percent per annum on an initial notional amount of $13,650 and then adjusting in accordance with an amortization schedule, which is effective from October 17, 2011 through loan maturity.
		(t)		The mortgage loan has two one-year extension options, subject to certain conditions, and includes a $25 million construction escrow with a balance of $15.8 million to be drawn at December 31, 2014.
		(u)		The Company’s equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (“IRR”) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
		(v)		Principal balance of $127,600 bears interest at 5.114 percent and matures in August 27, 2023; principal balance of $65,786 bears interest at rates ranging from LIBOR+5.0 percent to LIBOR+5.75 percent and matures in August 27, 2016; principal balance of $10,425 bears interest at LIBOR+6.0 percent matures in August 27, 2015.
	(w)		Includes the Company’s pari-passu interests of $6.2 million in five properties and Company’s subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (“IRR”) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions – Sales).
	(x)		Principal balance of $41,240 bears interest at 4.95 percent and matures on July 1, 2017; principal balance of $70,903 bears interest at rates ranging from 5.65 percent to 6.75 percent and matures on September 9, 2017; principal balance of $14,250 bears interest at 4.88 percent and matures on July 6, 2024; principal balance of $63,400 bears interest at 4.93 percent and matures on July 6, 2044; principal balance of $15,050 bears interest at 4.71 percent and matures on August 6, 2044.
	(y)		Balance includes: (i) mortgage loan, collateralized by the hotel property, with  a balance of $61,519, bears interest at 6.15 percent and matures in November 2016, and (ii) loan with a balance of $4.1 million, bears interest at fixed rates ranging from 6.09 percent to 6.62 percent and matures in August 1, 2020.  The Company posted a $4.1 million letter of credit in support of this loan, half of which is indemnified by the partner.
	(z)		The joint venture collected net proceeds of $47.2 million at maturity, of which the Company received its share of $37.8 million on August 6, 2014.
	(aa)		The construction/permanent loan has a maximum borrowing amount of $192,000.
(ab)See discussion Unconsolidated Joint Venture Transactions following in this footnote.
(ac)Includes undivided interests in the same manner as investments in noncontrolling partnership, pursuant to ASC 970-323-25-12.  See discussion in Unconsolidated Joint Venture Transactions following in this footnote.
(ad)The Company owns other interests in various unconsolidated joint ventures, including interests in assets previously owned and interest in ventures whose businesses are related to its core operations. These ventures are not expected to significantly impact the Company's operations in the near term.
(ae) See Note 10: Mortgages, Loans Payable and Other Obligations for debt secured by interests in these assets.
(af)The negative carrying amount for this venture of $1,854 and $1,706 as of December 31, 2014 and 2013, respectively, were included in accounts payable, accrued expenses and other liabilities.
The following is a summary of the Company’s equity in earnings (loss) of unconsolidated joint ventures for the years ended December 31, 2014 and 2013: (dollars in thousands)
		Year Ended December 31,
Entity / Property Name		2014			2013			2012
Multi-family
Marbella RoseGarden, L.L.C./ Marbella	$	-19		$	-540		$	13
RoseGarden Monaco Holdings, L.L.C./ Monaco		-1,040			-1,560			-311
Rosewood Lafayette Holdings, L.L.C./ Highlands at Morristown Station		-853			-1,131			-197
PruRose Port Imperial South 15, LLC /RiversEdge at Port Imperial		-			-606			-533
Rosewood Morristown, L.L.C. / Metropolitan at 40 Park		-345			-509			-25
Overlook Ridge JV, L.L.C./ Quarrystone at Overlook Ridge		-			-			-
Overlook Ridge JV 2C/3B, L.L.C./The Chase at Overlook Ridge		-384			293			-11
PruRose Riverwalk G, L.L.C./ RiverTrace at Port Imperial		-2,139			-985			-142
Elmajo Urban Renewal Associates, LLC / Lincoln Harbor (Bldg A&C)		-203			-345			-83
Crystal House Apartments Investors LLC / Crystal House		-139			-2,639			-
Portside Master Company, L.L.C./ Portside at Pier One - Bldg 7		-1,163			-421			-5
PruRose Port Imperial South 13, LLC / RiverParc at Port Imperial		-863			-664			-87
Roseland/Port Imperial Partners, L.P./ Riverwalk C		-646			-740			-
RoseGarden Marbella South, L.L.C./ Marbella II		-			-57			-13
Estuary Urban Renewal Unit B, LLC / Lincoln Harbor (Bldg B)		-15			-157			-
Riverpark at Harrison I, L.L.C./ Riverpark at Harrison		-150			-			-
Capitol Place Mezz LLC / Station Townhouses		-75			-			-
Harborside Unit A Urban Renewal, L.L.C. / URL Harborside		-218			-			-
RoseGarden Monaco, L.L.C./ San Remo Land		-			-			-
Grand Jersey Waterfront URA, L.L.C./ Liberty Landing		-54			-77			-
Office
Red Bank Corporate Plaza, L.L.C./ Red Bank		380			372			360
12 Vreeland Associates, L.L.C./ 12 Vreeland Road		106			74			427
BNES Associates III / Offices at Crystal Lake		240			-14			-323
Hillsborough 206 Holdings, L.L.C./ Hillsborough 206		-10			-35			-
KPG-P 100 IMW JV, LLC / 100 Independence Mall West		-1,887			-913			-
Keystone-Penn		-			-			-
Keystone-TriState		-318			-			-
KPG-MCG Curtis JV, L.L.C./ Curtis Center		624			-			-
Other
Plaza VIII & IX Associates, L.L.C./ Vacant land (parking operations)		320			99			30
Roseland/North Retail, L.L.C./ Riverwalk at Port Imperial		-102			-230			-80
South Pier at Harborside / Hyatt Regency Jersey City on the Hudson		2,602			2,519			2,368
Stamford SM LLC / Senior Mezzanine Loan		2,337			3,719			3,078
Other		1,591			2,220			-377
Company's equity in earnings (loss) of unconsolidated joint ventures	$	-2,423		$	-2,327		$	4,089
Summary Of Financial Position Of Unconsolidated Joint Ventures
				December 31,			December 31,
				2014			2013
	Assets:
	Rental property, net		$	1,534,812		$	755,038
	Loan receivable			-			45,050
	Other assets			398,173			582,989
	Total assets		$	1,932,985		$	1,383,077
	Liabilities and partners'/
	members' capital:
	Mortgages and loans payable		$	1,060,020		$	637,709
	Other liabilities			211,340			87,231
	Partners'/members' capital			661,625			658,137
	Total liabilities and
	partners'/members' capital		$	1,932,985		$	1,383,077
Summary Of The Results Of Operations Of Unconsolidated Joint Ventures
			Year Ended December 31,
			2014			2013			2012
	Total revenues	$	305,034		$	255,510		$	68,183
	Operating and other expenses		-233,320			-217,739			-37,008
	Depreciation and amortization		-42,985			-32,889			-10,139
	Interest expense		-32,862			-16,709			-6,775
	Net income (loss)	$	-4,133		$	-11,827		$	14,261

Deferred_Charges_Goodwill_And_1

Deferred Charges, Goodwill And Other Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Schedule Of Deferred Charges, Goodwill And Other Assets
			December 31,
	(dollars in thousands)		2014			2013
	Deferred leasing costs	$	239,138		$	258,648
	Deferred financing costs		24,042			25,366
			263,180			284,014
	Accumulated amortization		-122,358			-131,669
	Deferred charges, net		140,822			152,345
	Notes receivable (1)		21,491			21,986
	In-place lease values, related intangibles and other assets, net (2) (3)		6,565			13,659
	Goodwill		2,945			2,945
	Prepaid expenses and other assets, net		32,827			27,584
	Total deferred charges, goodwill and other assets, net	$	204,650		$	218,519
		-1		Includes as of December 31, 2014: a mortgage receivable for $10.4 million which bears interest at LIBOR plus six percent and matures in August 2015; a note receivable for $7.8 million which bears interest at eight percent and matures in October 2017; and an interest-free note receivable with a net present value of $3.3 million and matures in April 2023.  The Company believes these balances are fully collectable.
		-2		In accordance with ASC 805, Business Combinations, the Company recognizes rental revenue of acquired above and below market lease intangibles over the terms of the respective leases.  The impact of amortizating the acquired above and below-market lease intangibles increased revenue by approximately $0.7 million, $1.5 million and $1.4 million for the years ended December 31, 2014, 2013 and 2012, respectively.  The following table summarizes, as of December 31, 2014, the scheduled amortization of the Company’s acquired above and below-market lease intangibles for each of the five succeeding years (dollars in thousands).
			Acquired Above-			Acquired Below-
			Market Lease			Market Lease			Total
	Year		Intangibles			Intangibles			Amortization
	2015	$	-338		$	564		$	226
	2016		-288			370			82
	2017		-261			364			103
	2018		-233			310			77
	2019		-209			156			-53
		-3		In accordance with ASC 805, Business Combinations, the value of acquired in-place lease intangibles are amortized to expense over the remaining initial terms of the respective leases.  The impact of the amortization of acquired in-place lease values is included in depreciation and amortization expense and amounted to approximately $6.9 million, $10.7 million and $10.2 million for the years ended December 31, 2014, 2013 and 2012, respectively.  The following table summarizes, as of December 31, 2014, the scheduled amortization of the Company’s acquired in-place lease values for each of the five succeeding years (dollars in thousands).
	Year
	2015		$	1,231
	2016			1,224
	2017			918
	2018			-
	2019			-
Summary Of Notional Fair Value Of Derivative Financial Instruments
			Notional			Strike			Effective	Expiration
			Value	(a)		Rate			Date	Date		Fair Value
	LIBOR Cap	$	51,000			1.5	%		Sep-14	Oct-15	$	1
	LIBOR Cap		24,000			1.5	%		Sep-14	Oct-15		1
	LIBOR Cap		51,000			1.75	%		Oct-15	Oct-16		64
	LIBOR Cap		24,000			1.75	%		Oct-15	Oct-16		29
											$	95
		(a)		The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks.
Acquired Above And Below Market Lease Intangibles [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Summary Of Scheduled Amortization
			Acquired Above-			Acquired Below-
			Market Lease			Market Lease			Total
	Year		Intangibles			Intangibles			Amortization
	2015	$	-338		$	564		$	226
	2016		-288			370			82
	2017		-261			364			103
	2018		-233			310			77
	2019		-209			156			-53
Acquired In-Place Lease Intangibles [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Summary Of Scheduled Amortization
	Year
	2015		$	1,231
	2016			1,224
	2017			918
	2018			-
	2019			-

Restricted_Cash_Tables

Restricted Cash (Tables)	12 Months Ended
	Dec. 31, 2014
Restricted Cash [Abstract]
Schedule Of Restricted Cash
			December 31,
			2014		2013
	Security deposits	$	7,795	$	8,534
	Escrow and other reserve funds		26,450		11,260
	Total restricted cash	$	34,245	$	19,794

Discontinued_Operations_Tables

Discontinued Operations (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations [Abstract]
Summary Of Income From Discontinued Operations And Related Realized And Unrealized Gains (Losses)
		Year Ended December 31,
			2013			2012
	Total revenues	$	33,601		$	66,882
	Operating and other expenses		-13,454			-26,484
	Depreciation and amortization		-8,218			-17,765
	Interest expense		-118			-755
	Income from discontinued operations		11,811			21,878
	Loss from early extinguishment of debt		-703			-
	Impairments (1)		-23,851			-8,400
	Unrealized losses on disposition of rental property (2)		-			-9,213
	Realized gains on disposition of rental property		83,371			4,438
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		59,520			-13,175
	Total discontinued operations, net	$	70,628		$	8,703
	(1)Represents impairment charges recorded on certain properties prior to their sale.
	(2)Represents valuation allowances on properties identified as held for sale in 2012, as follows:
		(i)		At March 31, 2012, the Company identified as held for sale its 47,700 square foot office building located at 95 Chestnut Ridge Road in Montvale, New Jersey. The Company determined that the carrying amount of this property was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $0.5 million at March 31, 2012. On July 25, 2012, the Company sold the building for approximately $4.0 million (with no gain from the sale).
		(ii)		At March 31, 2012, the Company identified as held for sale three office buildings totaling 222,258 square feet in Moorestown, New Jersey. The Company determined that the aggregate carrying amount of these properties was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $1.6 million at June 30, 2012. On November 7, 2012, the Company sold the buildings for approximately $19.4 million and recognized a loss of approximately $0.1 million from the sale.
		(iii)		At December 31, 2012, the Company identified as held for sale its 248,400 square foot office building located at 19 Skyline Drive in Hawthorne, New York. The Company determined that the carrying amount of this property was not expected to be recovered from estimated sales proceeds and accordingly recognized a valuation allowance of $7.1 million at December 31, 2012. Also at December 31, 2012, the Company identified as held for sale its 204,057 square foot office building located at 55 Corporate Drive in Bridgewater, New Jersey. The two properties held for sale at December 31, 2012 carried an aggregate book value of $60.9 million, net of accumulated depreciation of $16.8 million and a valuation allowance of $7.1 million.  As of April 10, 2013, the Company sold 19 Skyline Drive for approximately $16.1 million and recognized a gain of approximately $0.1 million.  As of April 26, 2013, the Company sold 55 Corporate Drive for approximately $71 million and recognized a gain of approximately $19.7 million.

Senior_Unsecured_Notes_Tables

Senior Unsecured Notes (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Summary Of Senior Unsecured Notes
			December 31,			Effective
			2014		2013	Rate (1)
	5.125% Senior Unsecured Notes, due February 15, 2014 (2)		-	$	200,030	5.110	%
	5.125% Senior Unsecured Notes, due January 15, 2015 (3)		-		149,902	5.297	%
	5.800% Senior Unsecured Notes, due January 15, 2016	$	200,086		200,161	5.806	%
	2.500% Senior Unsecured Notes, due  December 15, 2017		249,150		248,855	2.803	%
	7.750% Senior Unsecured Notes, due August 15, 2019		249,013		248,799	8.017	%
	4.500% Senior Unsecured Notes, due April 18, 2022		299,565		299,505	4.612	%
	3.150% Senior Unsecured Notes, due May 15, 2023		269,930		269,323	3.517	%
	Total senior unsecured notes	$	1,267,744	$	1,616,575
	(1)Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.
	(2)On February 17, 2014, the Company repaid these notes at their maturity using available cash and borrowings on the Company’s unsecured revolving credit facility.
	(3)These notes were redeemed on December 17, 2014. The redemption price, including a make-whole premium, was 100.380 percent of the principal amount of the Notes, plus all accrued and unpaid interest up to the Redemption Date. The Company funded the redemption price, including accrued and unpaid interest, of approximately $153.8 million using available cash and borrowings on the Company’s unsecured revolving credit facility.  In connection with the redemption, the Company recorded approximately $0.6 million as a loss from early extinguishment of debt (including the write-off of unamortized deferred financing costs).

Unsecured_Revolving_Credit_Fac1

Unsecured Revolving Credit Facility (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Change In The Operating Partnership's Unsecured Debt Ratings
	Operating Partnership's	Interest Rate -
	Unsecured Debt Ratings:	Applicable Basis Points	Facility Fee
	Higher of S&P or Moody's	Above LIBOR	Basis Points
	No ratings or less than BBB-/Baa3	170.0	35.0
	BBB- or Baa3 (current)	130.0	30.0
	BBB or Baa2	110.0	20.0
	BBB+ or Baa1	100.0	15.0
	A- or A3 or higher	92.5	12.5

Mortgages_Loans_Payable_And_Ot1

Mortgages, Loans Payable And Other Obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Summary Of Mortgages, Loans Payable And Other Obligations
				Effective				December 31,
	Property Name	Lender		Rate (a)				2014			2013	Maturity
	6301 Ivy Lane (b)	RGA Reinsurance Company		5.520	%			-		$	5,447	-
	395 West Passaic (c)	State Farm Life Insurance Co.		6.004	%			-			9,719	-
	35 Waterview Boulevard (d)	Wells Fargo CMBS		6.348	%			-			18,417	-
	233 Canoe Brook Road (e)	The Provident Bank		4.375	%			-			3,877	-
	Port Imperial South 4/5 (f)	Wells Fargo Bank N.A.	LIBOR+3.50		%			-			36,950	-
	6 Becker, 85 Livingston,	Wells Fargo CMBS		10.260	%		$	65,035			64,233	8/11/14	(h)
	75 Livingston &
	20 Waterview (g)
	4 Sylvan	Wells Fargo CMBS		10.260	%			14,575			14,538	8/11/14	(h)
	10 Independence	Wells Fargo CMBS		10.260	%			16,924			16,638	8/11/14	(h)
	Overlook - Site IIID,IIIC, IIIA (i)	Wells Fargo Bank N.A.	LIBOR+3.50		%			17,260			-	3/2/15
	Overlook - Site IIB (Quarrystone I) (i)	Wells Fargo Bank N.A.	LIBOR+2.50		%			5,787			-	4/14/15
	9200 Edmonston Road (j)	Principal Commercial Funding L.L.C.		5.534	%			3,951			4,115	5/1/15
	Port Imperial South	Wells Fargo Bank N.A.	LIBOR+1.75		%			44,119			43,278	9/19/15
	4 Becker	Wells Fargo CMBS		9.550	%			39,421			38,820	5/11/16
	5 Becker (k)	Wells Fargo CMBS		12.830	%			13,867			13,092	5/11/16
	210 Clay  (l)	Wells Fargo CMBS		13.420	%			13,330			12,767	5/11/16
	Curtis Center (m)	CCRE & PREFG	LIBOR+5.912		%	(p)		64,000			-	10/9/16
	Various (n)	Prudential Insurance		6.332	%			145,557			147,477	1/15/17
	150 Main St.	Webster Bank	LIBOR+2.35		%			1,193	(r)		-	3/30/17
	23 Main Street	JPMorgan CMBS		5.587	%			29,210			29,843	9/1/18
	Harborside Plaza 5	The Northwestern Mutual Life		6.842	%			221,563			225,139	11/1/18
		Insurance Co. & New York Life
		Insurance Co.
	100 Walnut Avenue	Guardian Life Insurance Co.		7.311	%			18,542			18,792	2/1/19
	One River Center (o)	Guardian Life Insurance Co.		7.311	%			42,476			43,049	2/1/19
	Park Square	Wells Fargo Bank N.A.	LIBOR+1.872		%	(q)		27,500			-	4/10/19
	Port Imperial South 4/5 Retail	American General Life & A/G PC		4.559	%			4,000			-	12/1/21
	Port Imperial South 4/5 Garage	American General Life & A/G PC		4.853	%			32,600			-	12/1/29
	Total mortgages, loans payable and other obligations						$	820,910		$	746,191
		(a)		Reflects effective rate of debt, including deferred financing costs, comprised of the cost of terminated treasury lock agreements (if any), debt initiation costs, mark-to-market adjustment of acquired debt and other transaction costs, as applicable.
		(b)		On April 1, 2014, the Company repaid the mortgage loan at par, using available cash.
		(c)		On May 1, 2014, the Company repaid the mortgage loan at par, using available cash.
		(d)		On May 12, 2014, the Company repaid the mortgage loan at par, using borrowings on the Company’s unsecured revolving credit facility.
		(e)		On April 30, 2014, the Company repaid the mortgage loan at par, using available cash.
		(f)		On November 3, 2014, the Company refinanced the mortgage loan with a different lender
		(g)		Mortgage is cross collateralized by the four properties.
		(h)		The loan was not repaid at maturity and the Company has begun discussions with the lender regarding a potential deed-in-lieu of foreclosure in satisfaction of the obligation.
		(i)		On August 15, 2014, the Company assumed these loans as a result of its acquisition of interests which increased its ownership to 100 percent in certain previously unconsolidated joint ventures which owned developable land.
		(j)		The mortgage loan originally matured on May 1, 2013.  The maturity date was extended until May 1, 2015 with the same interest rate.  Excess cash flow, as defined, is being held by the lender for re-leasing costs.  The deed for the property was placed in escrow and is available to the lender in the event of default or non-payment at maturity.
		(k)		The cash flow from this property is insufficient to cover operating costs and debt service.  Consequently, the Company notified the lender and suspended debt service payments in August 2013.  The Company has begun discussions with the lender regarding a deed-in-lieu of foreclosure and began remitting available cash flow to the lender effective August 2013.
		(l)		The cash flow from this property is insufficient to cover operating costs and debt service.  Consequently, the Company notified the lender and suspended debt service payments in January 2015.
		(m)		The Company owns a 50 percent tenants-in-common interest in the Curtis Center Property.  The Company’s $64.0 million loan consists of its 50 percent interest in a $102 million senior loan with a current rate of 3.455 percent at December 31, 2014 and its 50 percent interest in a $26 million mezzanine loan (with a maximum borrowing capacity of $48 million) with a current rate of 9.661 percent at December 31, 2014.  The senior loan rate is based on a floating rate of one-month LIBOR plus 329 basis points and the mezzanine loan rate is based on a floating rate of one-month LIBOR plus 950 basis points.  The Company has entered into LIBOR caps for the periods of the loans.  The loans provide for three one-year extension options.
		(n)		Mortgage is cross collateralized by seven properties.  The Company has agreed, subject to certain conditions, to guarantee repayment of a portion of the loan.
		(o)		Mortgage is collateralized by the three properties comprising One River Center.
		(p)		The effective interest rate includes amortization of deferred financing costs of 1.362 percent.
		(q)		The effective interest rate includes amortization of deferred financing costs of 0.122 percent.
		(r)		This construction loan has a maximum borrowing capacity of $28.8 million.
	SCHEDULED PRINCIPAL PAYMENTS
	Scheduled principal payments for the Company’s senior unsecured notes (see Note 8), unsecured revolving credit facility (see Note 9) and mortgages, loans payable and other obligations as of December 31, 2014 are as follows: (dollars in thousands)
			Scheduled			Principal
	Period		Amortization			Maturities			Total
	2015	$	8,811		$	167,589		$	176,400
	2016		8,311			333,272			341,583
	2017		7,275			392,345			399,620
	2018		7,311			231,536			238,847
	2019		723			331,567			332,290
	Thereafter		6,329			605,205			611,534
	Sub-total		38,760			2,061,514			2,100,274
	Adjustment for unamortized debt
	discount/premium, net, as of
31-Dec-14		-11,620			-			-11,620
Totals/Weighted Average	$	27,140		$	2,061,514		$	2,088,654

MackCali_Realty_LPs_Partners_C1

Mack-Cali Realty, L.P's Partners' Capital (Tables)	12 Months Ended
	Dec. 31, 2014
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Schedule Of Stock Option Plans
					Weighted			Aggregate
					Average			Intrinsic
		Shares			Exercise			Value
		Under Options			Price			$(000’s)
	Outstanding at January 1, 2012	183,870		$	29.51			-
	Exercised/Cancelled	-			-
	Outstanding at December 31, 2012  ($28.47 – $45.47)	183,870		$	29.51			-
	Lapsed or Cancelled	-168,870			28.53
	Outstanding at December 31, 2013  ($35.59 – $45.47)	15,000		$	40.54			-
	Granted	5,000			21.25
	Lapsed or Cancelled	-10,000			38.07
	Outstanding at December 31, 2014  ($21.25 – $45.47)	10,000		$	33.36			-
	Options exercisable at December 31, 2014	5,000
	Available for grant at December 31, 2014	4,424,013
Schedule Of Weighted Average Assumptions
	Expected life (in years)		6
	Risk-free interest rate		1.50	%
	Volatility		20.26	%
	Dividend yield		5.65	%
Schedule Of Restricted Stock Awards
					Weighted-Average
					Grant – Date
		Shares			Fair Value
	Outstanding at January 1, 2012	187,447		$	33.82
	Granted (a)	70,758			25.28
	Vested	-123,877			31.30
	Outstanding at December 31, 2012	134,328		$	31.65
	Granted (b) (c)	168,841			23.99
	Vested	-149,463			29.63
	Forfeited	-146			26.36
	Outstanding at December 31, 2013	153,560		$	25.20
	Granted (d) (e) (f)	376,719			20.04
	Vested	-183,214			22.37
	Forfeited	-119			26.36
	Outstanding at December 31, 2014	346,946		$	21.09
	(a)Included in the 70,758 Restricted Stock Awards granted in 2012 were 42,273 awards granted to the Corporation’s three executive officers, Mitchell E. Hersh, Barry Lefkowitz and Roger W. Thomas.
	(b)Included in the 168,841 Restricted Stock Awards granted in 2013 were 106,933 awards granted to the Corporation’s four executive officers, Mitchell E. Hersh, Barry Lefkowitz, Roger W. Thomas and Anthony Krug.
	(c)Includes 63,933 Performance Shares which were legally granted in 2013 for which the 2013 performance goals were not met, which may be earned if subsequent years’ performance goals are met.
	(d)Included in the 376,719 Restricted Stock Awards granted in 2014 were 8,211 awards granted to the Corporation’s two executive officers, Anthony Krug and Gary Wagner.
	(e)Includes 42,000 Performance Shares which were legally granted in 2013 for which the 2014 performance goals were set by the Committee on March 31, 2014.  Also includes 87,734 shares which were additionally considered granted for accounting purposes to two executive officers in connection with their departure effective March 31, 2014, which vested on April 1, 2014.
	(f)Includes 126,000 Performance Shares which were legally granted in 2013 for which future performance goals had not yet been set by the Committee.  These awards were not considered granted for accounting purposes until these goals are set.  These were  considered granted in 2014 for accounting purposes in connection with the announcement of the departure of Mitchell E. Hersh in the fourth quarter 2014.
	As of December 31, 2014, the Company had $1.5 million of total unrecognized compensation cost related to unvested Restricted Stock Awards granted under the Corporation’s stock compensation plans.  That cost is expected to be recognized over a weighted average period of 1.5 years.
Schedule Of Basic And Diluted Earnings Per Unit
				Year Ended December 31,
	Computation of Basic EPU			2014					2013				2012
	Income (loss) from continuing operations		$	31,391				$	-89,686			$	37,566
	Add: Noncontrolling interest in consolidated joint ventures			778					2,199				330
	Income (loss) from continuing operations available to common unitholders			32,169					-87,487				37,896
	Income from discontinued operations available to common
	unitholders			-					70,628				8,703
	Net income (loss) available to common unitholders		$	32,169				$	-16,859			$	46,599
	Weighted average common units			99,999					99,785				99,922
	Basic EPU:
	Income (loss) from continuing operations available to common unitholders		$	0.32				$	-0.88			$	0.38
	Income from discontinued operations available to common
	unitholders			-					0.71				0.09
	Net income (loss) available to common unitholders		$	0.32				$	-0.17			$	0.47
				Year Ended December 31,
	Computation of Diluted EPU			2014			2013				2012
	Income (loss) from continuing operations available to common unitholders		$	32,169		$	-87,487			$	37,896
	Income from discontinued operations for diluted earnings
	per unit			-			70,628				8,703
	Net income (loss) available to common unitholders		$	32,169		$	-16,859			$	46,599
	Weighted average common unit			100,041			99,785				99,996
	Diluted EPU:
	Income (loss) from continuing operations available to common unitholders		$	0.32		$	-0.88			$	0.38
	Income from discontinued operations available to common
	unitholders			-			0.71				0.09
	Net income (loss) available to common unitholders		$	0.32		$	-0.17			$	0.47
	The following schedule reconciles the units used in the basic EPU calculation to the units used in the diluted EPU calculation: (in thousands)
		Year Ended December 31,
		2014	2013	2012
	Basic EPU units	99,999	99,785	99,922
	Add:   Restricted Stock Awards	42	-	74
	Diluted EPU units	100,041	99,785	99,996

Commitments_And_Contingencies_

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments And Contingencies [Abstract]
Future Minimum Rental Payments Of Ground Leases
	Year		Amount
	2015	$	371
	2016		371
	2017		267
	2018		232
	2019		235
	2020 through 2084		15,584
	Total	$	17,060

Tenant_Leases_Tables

Tenant Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Tenant Leases [Abstract]
Future Minimum Rentals To Be Received Under Non-Cancelable Operating Leases
	Year		Amount
	2015	$	454,461
	2016		420,115
	2017		368,666
	2018		288,977
	2019		234,368
	2020 and thereafter		934,117
	Total	$	2,700,704

Segment_Reporting_Tables

Segment Reporting (Tables)	12 Months Ended
	Dec. 31, 2014
Segment Reporting [Abstract]
Schedule Of Segment Reporting Information, By Segment
			Real Estate
			Commercial				Multi-family			Corporate		Total
			& Other		Multi-family		Services			& Other (d)		Company
	Total revenues:
	2014	$	585,491	$	24,971	$	30,533	(e)	$	-4,196	$	636,799
	2013		621,352		12,792		25,710	(f)		7,177		667,031
	2012		635,278		-		4,465			10,889		650,632
	Total operating and
	interest expenses (a):
	2014	$	295,416	$	12,235	$	38,377		$	138,733	$	484,761
	2013		285,755		6,482		32,415			135,963		460,615
	2012		276,700		-		5,195			146,122		428,017
	Equity in earnings (loss) of
	unconsolidated joint ventures:
	2014	$	4,236	$	-8,790	$	2,131		$	-	$	-2,423
	2013		6,280		-10,615		2,008			-		-2,327
	2012		5,564		-1,475		-			-		4,089
	Net operating income (loss) (b):
	2014	$	294,311	$	3,946	$	-5,713		$	-142,929	$	149,615
	2013		341,877		-4,305		-4,697			-128,786		204,089
	2012		364,142		-1,475		-730			-135,233		226,704
	Total assets:
	2014	$	3,636,126	$	492,362	$	11,158		$	52,601	$	4,192,247
	2013		3,886,574		377,237		10,488			241,029		4,515,328
	Total long-lived assets (c):
	2014	$	3,344,840	$	318,524	$	3,858		$	3,482	$	3,670,704
	2013		3,620,494		240,501		3,468			3,730		3,868,193
	Total investments in
	unconsolidated joint ventures:
	2014	$	81,649	$	164,912	$	907		$	-	$	247,468
	2013		53,160		127,276		693			-		181,129
	(a)Total operating and interest expenses represent the sum of: real estate taxes; utilities; operating services; direct construction costs; real estate services expenses; general and administrative and interest expense (net of interest income). All interest expense, net of interest and other investment income, (including for property-level mortgages) is excluded from segment amounts and classified in Corporate & Other for all periods.
	(b)Net operating income represents total revenues less total operating and interest expenses (as defined in Note “a”), plus equity in earnings (loss) of unconsolidated joint ventures, for the period.
	(c)Long-lived assets are comprised of net investment in rental property, unbilled rents receivable and goodwill.
	(d)Corporate & Other represents all corporate-level items (including interest and other investment income, interest expense, non-property general and administrative expense, construction services revenue and direct construction costs) as well as intercompany eliminations necessary to reconcile to consolidated Company totals.
	(e)Includes $2.3 million of fees earned for this period from the multi-family real estate segment, which are eliminated in consolidation.
	(f)Includes $2.2 million of fees earned for this period from the multi-family real estate segment, which are eliminated in consolidation.
	The following schedule reconciles net operating income to net income available to common unitholders: (dollars in thousands)
		Year  Ended December 31,
			2014		2013		2012
	Net operating income	$	149,615	$	204,089	$	226,704
	Less:
	Depreciation and amortization		-172,490		-182,766		-174,333
	Realized gains  on disposition of
	rental property, net		54,848		-		-
	Loss from early extinguishment of debt		-582		-156		-4,960
	Impairments		-		-110,853		-9,845
	Income (loss) from continuing operations		31,391		-89,686		37,566
	Discontinued operations:
	Income from discontinued operations		-		11,811		21,878
	Loss from early extinguishment of debt		-		-703		-
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		-		59,520		-13,175
	Total discontinued operations, net		-		70,628		8,703
	Net income (loss)		31,391		-19,058		46,269
	Noncontrolling interest in consolidated joint ventures		778		2,199		330
	Net income (loss) available to common unitholders	$	32,169	$	-16,859	$	46,599

Condensed_Quarterly_Financial_1

Condensed Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2014
Condensed Quarterly Financial Information [Abstract]
Schedule Of Quarterly Financial Information
	Quarter Ended 2014		31-Dec			30-Sep		30-Jun		31-Mar
	Total revenues	$	151,414		$	155,489	$	160,300	$	169,596
	Operating and other expenses		64,177			64,374		65,788		81,854
	Real estate service salaries		5,923			6,933		6,571		6,709
	General and administrative		23,950			12,665		13,673		22,881
	Depreciation and amortization		40,811			41,983		44,711		44,985
	Total expenses		134,861			125,955		130,743		156,429
	Operating Income		16,553			29,534		29,557		13,167
	Interest expense		-27,420			-27,353		-28,159		-29,946
	Interest and other investment income		1,399			908		922		386
	Equity in earnings (loss) of unconsolidated
	joint ventures		-363			-1,268		443		-1,235
	Realized gains (losses) on disposition of rental properties		-			264		54,584		-
	Loss from early extinguishment of debt		-582			-		-		-
	Total other (expense) income		-26,966			-27,449		27,790		-30,795
	Income (loss) from continuing operations		-10,413			2,085		57,347		-17,628
	Discontinued operations:
	Income (loss) from discontinued operations		-			-		-		-
	Loss from early extinguishment of debt
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		-			-		-		-
	Total discontinued operations, net		-			-		-		-
	Net income (loss)		-10,413			2,085		57,347		-17,628
	Noncontrolling interest in consolidated joint ventures		21			145		290		322
	Net income (loss) available to common unitholders	$	-10,392		$	2,230	$	57,637	$	-17,306
	Basic earnings per common unit:
	Income (loss) from continuing operations	$	-0.1		$	0.02	$	0.58	$	-0.17
	Discontinued operations		-			-		-		-
	Net income (loss) available to common unitholders	$	-0.1		$	0.02	$	0.58	$	-0.17
	Diluted earnings per common units:
	Income (loss) from continuing operations	$	-0.1		$	0.02	$	0.58	$	-0.17
	Discontinued operations		-			-		-		-
	Net income (loss) available to common unitolders	$	-0.1		$	0.02	$	0.58	$	-0.17
	Distributions declared per common unit	$	0.15		$	0.15	$	0.15	$	0.30
	Quarter Ended 2013		31-Dec			30-Sep		30-Jun		31-Mar
	Total revenues	$	165,267		$	162,505	$	168,346	$	170,913
	Operating and other expenses		67,862			64,467		58,900		63,245
	Direct construction costs		-			609		6,511		7,825
	Real estate service salaries		6,907			5,552		5,304		4,953
	General and administrative		10,447			12,151		13,111		11,973
	Depreciation and amortization		47,666			46,087		45,665		43,348
	Impairments (1)		62,153	-2		48,700		-		-
	Total expenses		195,035			177,566		129,491		131,344
	Operating Income		-29,768			-15,061		38,855		39,569
	Interest expense		-31,626			-30,936		-31,270		-29,869
	Interest and other investment income		1,616			187		1,094		6
	Equity in earnings (loss) of unconsolidated
	joint ventures		-268			-229		-80		-1,750
	Loss from early extinguishment of debt		-156			-		-		-
	Total other (expense) income		-30,434			-30,978		-30,256		-31,613
	Income (loss) from continuing operations		-60,202			-46,039		8,599		7,956
	Discontinued operations:
	Income (loss) from discontinued operations		-9			2,157		4,530		5,133
	Loss from early extinguishment of debt		-			-		-703		-
	Realized gains (losses) and unrealized losses on
	disposition of rental property and impairments, net		-1,559	-3		47,321		13,758		-
	Total discontinued operations, net		-1,568			49,478		17,585		5,133
	Net income (loss)		-61,770			3,439		26,184		13,089
	Noncontrolling interest in consolidated joint ventures		237			1,838		62		62
	Net income (loss) available to common unitholders	$	-61,533		$	5,277	$	26,246	$	13,151
	Basic earnings per common unit:
	Income (loss) from continuing operations	$	-0.6		$	-0.45	$	0.09	$	0.08
	Discontinued operations		-0.02			0.50		0.17		0.05
Net income (loss) available to common unitholders	$	-0.62		$	0.05	$	0.26	$	0.13
Diluted earnings per common unit:
Income (loss) from continuing operations	$	-0.6		$	-0.45	$	0.09	$	0.08
Discontinued operations		-0.02			0.50		0.17		0.05
Net income (loss) available to common unitholders	$	-0.62		$	0.05	$	0.26	$	0.13
Distributions declared per common unit	$	0.30		$	0.30	$	0.30	$	0.45
(1)Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions – Impairments on Properties Held and Used.
(2)During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
(3)During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.

Organization_And_Basis_Of_Pres1

Organization And Basis Of Presentation (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	sqft
	state
	property
Real Estate Properties [Line Items]
Percentage of ownership interest	88.90%	88.10%
Number of properties owned or investment interests	283
Aggregate square feet of the property owned or investment interest	31,000,000
Number of states where properties are located	7
Consolidated joint ventures, total real estate assets	$242.90	$219.90
Consolidated joint ventures, mortgages	94.3	81.9
Consolidated joint ventures, other liabilities	$15.70	$18.30
Commercial Properties [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	264
Number of tenants	2,000
Multi-Family Properties [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	19
Number of units	5,484
Office And Office/Flex Buildings [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	249
Aggregate square feet of the property owned or investment interest	30,500,000
Industrial/Warehouse Facilities [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	6
Aggregate square feet of the property owned or investment interest	387,400
Unconsolidated Joint Venture Multi-Family Properties [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	13
Number of units	4,183
Unconsolidated Joint Venture Office Buildings [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	36
Aggregate square feet of the property owned or investment interest	5,600,000
Parking/Retail [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	5
Aggregate square feet of the property owned or investment interest	121,500
Unconsolidated Joint Venture Parking/Retail Buildings [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	2
Aggregate square feet of the property owned or investment interest	81,500
Unconsolidated Joint Venture Hotel [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	1
Number of units	350
Land [Member]
Real Estate Properties [Line Items]
Number of properties owned or investment interests	3

Significant_Accounting_Policie3

Significant Accounting Policies (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jan. 06, 2015	Jan. 06, 2014
Significant Accounting Policies [Line Items]
Capitalized development and construction salaries and other related costs			$3,100,000	$4,400,000	$3,800,000
Construction, tenant improvement, and development in-progress	62,800,000	40,800,000	62,800,000	40,800,000
Maximum period after cessation of major construction activity that projects are considered complete			1 year
Threshold of investment value for discontinuation of equity method accounting	0		0
Amortization of deferred financing costs			3,274,000	3,172,000	2,669,000
Write off of unamortized deferred financing costs			12,000	156,000	593,000
Deferred leasing costs			3,840,000	4,223,000	4,354,000
Provision or benefit for income taxes			0
Difference between the estimated net basis and net assets of the rental property for federal income tax purposes	366,131,000		366,131,000
Taxable income			73,546,000	114,522,000	145,928,000
Deferred tax asset	14,400,000		14,400,000
General and limited partners common capital account units outstanding						99,950,528	99,792,777
Distributions payable, record date	6-Jan-15	6-Jan-14
Common unit distributions per common unit, declared	$0.15	$0.30
Distribution per common unit paid			$0.90	$1.50	$1.80
Percentage of ordinary income paid as dividend			77.00%	53.00%	75.00%
Percentage of return of capital paid as dividend			23.00%	33.00%	25.00%
Dividends paid, percent representing capital gain				14.00%
Distributions payable date	14-Jan-15	15-Jan-14
Restricted stock expense			8,139,000	2,387,000	3,642,000
Difference between other comprehensive income and net income			0	0	0
Accumulated other comprehensive income	0	0	0	0
Executive Officer [Member]
Significant Accounting Policies [Line Items]
Restricted stock expense			$5,824,000

Significant_Accounting_Policie4

Significant Accounting Policies (Estimated Useful Lives Of Assets) (Details)	12 Months Ended
	Dec. 31, 2014
Minimum [Member] | Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	5 years
Minimum [Member] | Furniture, Fixtures And Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	5 years
Maximum [Member] | Buildings And Improvements [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	40 years
Maximum [Member] | Furniture, Fixtures And Equipment [Member]
Property, Plant and Equipment [Line Items]
Estimated useful lives of assets	10 years

Real_Estate_Transactions_Acqui

Real Estate Transactions (Acquisitions) (Narrative) (Details) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Apr. 10, 2014	Aug. 15, 2014	Dec. 02, 2014	Dec. 31, 2013
		item
Real Estate Properties [Line Items]
Transaction costs	$2,100,000				$642,000
Acquisition and other investment fundings handled by intermediary	44,400,000
Andover Place [Member]
Real Estate Properties [Line Items]
Number of units		220
Cash consideration		37,700,000
Overlook Ridge Properties [Member]
Real Estate Properties [Line Items]
Cash consideration			16,600,000
Conshohocken, Pennsylvania [Member]
Real Estate Properties [Line Items]
Cash consideration				15,300,000
Curtis Center [Member]
Real Estate Properties [Line Items]
Indirect ownership interest	50.00%
Acquisition and other investment fundings handled by intermediary	40,100,000
Multi-Family Properties [Member]
Real Estate Properties [Line Items]
Number of units	5,484
Multi-Family Properties [Member] | Overlook Ridge Properties [Member]
Real Estate Properties [Line Items]
Percentage of additional interest acquired			25.00%
Indirect ownership interest			50.00%
Number of properties in which additional interest was acquired during period			2
Consolidated Land [Member] | Overlook Ridge Properties [Member]
Real Estate Properties [Line Items]
Percentage of interest in developable land			100.00%
Loans assumed			$23,000,000
Consolidated Land [Member] | Overlook Ridge Properties [Member] | Minimum [Member]
Real Estate Properties [Line Items]
Spread over LIBOR			2.50%
Consolidated Land [Member] | Overlook Ridge Properties [Member] | Maximum [Member]
Real Estate Properties [Line Items]
Spread over LIBOR			3.50%

Real_Estate_Transactions_Conso

Real Estate Transactions (Consolidation) (Narrative) (Details) (USD $)	0 Months Ended
	Aug. 22, 2013	Oct. 23, 2012	Dec. 31, 2014		Aug. 22, 2013	Oct. 23, 2012
						item
Real Estate Properties [Line Items]
Percentage of interest in venture				[1],[2],[3]
Eastchester Project [Member]
Real Estate Properties [Line Items]
Cash consideration	$4,900,000	$2,100,000
Percentage of interest in venture	76.25%	26.25%			76.25%	26.25%
Holding period gain (loss)	0
Number of units		108				108
Total project costs			50,000,000
Project costs incurred			13,900,000
Amount of project costs funded by members			21,200,000
Eastchester Project [Member] | Hudson Valley Land Holdings, L.L.C. [Member]
Real Estate Properties [Line Items]
Third party ownership percentage	23.75%	47.50%			23.75%	47.50%
Eastchester Project [Member] | JMP Eastchester, L.L.C. [Member]
Real Estate Properties [Line Items]
Third party ownership percentage		26.25%				26.25%
Eastchester Project [Member] | Parent Company [Member]
Real Estate Properties [Line Items]
Amount of project costs funded by members			20,900,000
Construction Loan [Member] | Eastchester Project [Member] | 150 Main Street, L.L.C. [Member]
Real Estate Properties [Line Items]
Maximum borrowing capacity			$28,800,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).

Real_Estate_Transactions_Impai

Real Estate Transactions (Impairments On Properties Held and Used) (Narrative) (Details) (USD $)	3 Months Ended				12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
					property		property
							sqft
Real Estate Properties [Line Items]
Impairments	$62,153,000	[1],[2]	$48,700,000	[1]	$110,853,000	$9,845,000
Number of impaired properties					18
Mortgage loan	746,191,000				746,191,000		820,910,000
Capitalization rate					8.50%
Minimum [Member]
Real Estate Properties [Line Items]
Discount rate					10.00%
Maximum [Member]
Real Estate Properties [Line Items]
Discount rate					15.00%
Roseland, Parsippany, Warren And Lyndhurst, New Jersey [Member]
Real Estate Properties [Line Items]
Number of impaired properties					9
Area of property (in square feet)	1,300,000				1,300,000
Mortgage loan	160,000,000				160,000,000
Fair Lawn, New Jersey, Woodcliff Lake, New Jersey, Stamford, Connecticut And Elmsford, New York [Member]
Real Estate Properties [Line Items]
Area of property (in square feet)							646,000
Number of properties sold							7
Morris Plains And Upper Saddle River, New Jersey [Member]
Real Estate Properties [Line Items]
Area of property (in square feet)							550,000
Number of impaired properties being considered for repositioning							2
Keystone Portfolio [Member]
Real Estate Properties [Line Items]
Impairments					$20,800,000
Keystone Portfolio [Member] | Fair Lawn, New Jersey, Woodcliff Lake, New Jersey, Stamford, Connecticut And Elmsford, New York [Member]
Real Estate Properties [Line Items]
Number of properties sold							6
[1]	Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions - Impairments on Properties Held and Used.
[2]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.

Real_Estate_Transactions_Sched

Real Estate Transactions (Schedule Of Purchase Price Allocation) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Business Acquisition [Line Items]
Land	8,535		$32,258
Buildings and improvements	27,609		195,258
Furniture, fixtures and equipment	459		3,290
Above market leases			24	[1]
In-place lease values	1,118	[2]	6,322	[1]
Total assets acquired	37,721		237,152
Less: Below market lease values	-25	[2]	593	[1]
Total liabilities assumed			593
Net cash paid at acquisition	37,696		236,559
Alterra At Overlook Ridge IA [Member]
Business Acquisition [Line Items]
Land			9,042
Buildings and improvements			50,671
Furniture, fixtures and equipment			801
In-place lease values			931	[1]
Total assets acquired			61,445
Less: Below market lease values			195	[1]
Total liabilities assumed			195
Net cash paid at acquisition			61,250
Alterra At Overlook Ridge IB [Member]
Business Acquisition [Line Items]
Land			12,055
Buildings and improvements			71,409
Furniture, fixtures and equipment			1,474
In-place lease values			3,148	[1]
Total assets acquired			88,086
Less: Below market lease values			136	[1]
Total liabilities assumed			136
Net cash paid at acquisition			87,950
Park Square [Member]
Business Acquisition [Line Items]
Land			4,000
Buildings and improvements			40,670
Furniture, fixtures and equipment			610
Above market leases			24	[1]
In-place lease values			1,249	[1]
Total assets acquired			46,553
Less: Below market lease values			177	[1]
Total liabilities assumed			177
Net cash paid at acquisition			46,376
Richmond Court [Member]
Business Acquisition [Line Items]
Land			2,992
Buildings and improvements			13,534
Furniture, fixtures and equipment			177
In-place lease values			356	[1]
Total assets acquired			17,059
Less: Below market lease values			36	[1]
Total liabilities assumed			36
Net cash paid at acquisition			17,023
Riverwatch Commons [Member]
Business Acquisition [Line Items]
Land			4,169
Buildings and improvements			18,974
Furniture, fixtures and equipment			228
In-place lease values			638	[1]
Total assets acquired			24,009
Less: Below market lease values			49	[1]
Total liabilities assumed			49
Net cash paid at acquisition			$23,960
In-Place And Below Market Leases [Member] | Maximum [Member]
Business Acquisition [Line Items]
Amortization period	1 year
[1]	In-place lease values and above/below market lease values will be amortized over one year or less.
[2]	In-place lease values and below market lease values will be amortized over one year or less.

Real_Estate_Transactions_Sched1

Real Estate Transactions (Schedule Of Properties Acquired) (Details) (USD $)	12 Months Ended			1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Jan. 31, 2014	Nov. 20, 2013
		item
		property
Business Acquisition [Line Items]
Number of Properties		5
Number of Apartment Units		1,081
Acquisition Cost		$236,559,000
Contingent consideration at fair value		405,000
Earn out paid	5,228,000	2,755,000
Alterra At Overlook Ridge IA [Member]
Business Acquisition [Line Items]
Number of Properties		1
Number of Apartment Units		310
Acquisition Cost		61,250,000	[1]
Alterra At Overlook Ridge IB [Member]
Business Acquisition [Line Items]
Number of Properties		1
Number of Apartment Units		412
Acquisition Cost		87,950,000	[1]
Park Square [Member]
Business Acquisition [Line Items]
Number of Properties		1
Number of Apartment Units		159
Acquisition Cost		46,376,000	[2]
Cash consideration		43,421,000
Contingent consideration at fair value					2,955,000
Amount of cash funded by qualified intermediary		42,613,355
Earn out paid				2,550,000
Richmond Ct / Riverwatch Commons [Member]
Business Acquisition [Line Items]
Number of Properties		2
Number of Apartment Units		200
Acquisition Cost		40,983,000	[3]
Amount of cash funded by qualified intermediary		$12,701,925
[1]	The acquisition cost was funded primarily through borrowings under the Companybs unsecured revolving credit facility.
[2]	The acquisition cost consisted of $43,421,000 in cash consideration and future purchase price earn out payment obligations, subsequent to conditions related to a real estate tax appeal, recorded at fair value of $2,955,000 at closing. $42,613,355 of the cash consideration was funded from funds held by a qualified intermediary, which were proceeds from the Companybs prior property sales. The remaining cash consideration was funded primarily from available cash on hand. $2,550,000 of the earn-out obligation amount was paid in January 2014, with the remaining balance of $405,000 still potentially payable in the future.
[3]	$12,701,925 of the acquisition cost was funded from funds held by a qualified intermediary, which were proceeds from the Companybs prior property sales. The remaining acquisition cost was funded primarily from available cash on hand.

Real_Estate_Transactions_Sched2

Real Estate Transactions (Schedule Of Net Assets Recorded Upon Consolidation) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Aug. 22, 2013
In Thousands, unless otherwise specified
Business Acquisition [Line Items]
Land	$8,535	$32,258
Eastchester Project [Member]
Business Acquisition [Line Items]
Land			5,585
Construction in progress			3,387
Real estate recorded upon consolidation			8,972
Cash and cash equivalents			79
Other assets			47
Accounts payable			-325
Working capital recorded upon consolidation			-199
Noncontrolling interest recorded upon consolidation			-1,252
Net assets recorded upon consolidation			$7,521

Real_Estate_Transactions_Sched3

Real Estate Transactions (Schedule Of Properties Which Commenced Initial Operations) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2013
	sqft
	item
Real Estate Properties [Line Items]
Number of Buildings	2
Rentable Square Feet	220,242
Garage Parking Spaces	850
Development Costs Incurred by Company	$102,267
14 Sylvan Way [Member]
Real Estate Properties [Line Items]
Number of Buildings	1
Rentable Square Feet	203,506
Development Costs Incurred by Company	51,611	[1]
Development Costs Per Square Foot	254
Port Imperial South 4/5 [Member]
Real Estate Properties [Line Items]
Number of Buildings	1
Rentable Square Feet	16,736
Garage Parking Spaces	850
Development Costs Incurred by Company	50,656	[2]
Land [Member] | 14 Sylvan Way [Member]
Real Estate Properties [Line Items]
Development Costs Incurred by Company	13,000
Land [Member] | Port Imperial South 4/5 [Member]
Real Estate Properties [Line Items]
Development Costs Incurred by Company	13,100
Lease [Member] | 14 Sylvan Way [Member]
Real Estate Properties [Line Items]
Development Costs Incurred by Company	$4,300
[1]	Development costs included approximately $13.0 million in land costs and $4.3 million in leasing costs. Amounts are as of December 31, 2013.
[2]	Development costs included approximately $13.1 million in land costs. Amounts are as of December 31, 2013.

Real_Estate_Transactions_Sched4

Real Estate Transactions (Schedule Of Property Sales) (Details) (USD $)	3 Months Ended					12 Months Ended					0 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Aug. 27, 2013
	item					sqft		sqft			property
	property					item		property
						property		item
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	24					16		24
Rentable Square Feet						2,610,931		3,006,409
Net Sales Proceeds						$319,239,000		$390,615,000	[1]
Net Book Value	307,244,000					264,391,000		307,244,000
Realized Gain (loss)						54,848,000		83,371,000	[2]
Impairment charge	62,153,000	[3],[4]	48,700,000	[3]				110,853,000		9,845,000
Valuation allowance						14,400,000
Note receivable, net present value	21,986,000	[5]				21,491,000	[5]	21,986,000	[5]
Loss from early extinguishment of debt					-703,000			-703,000
Number of impaired properties								18
Number of land parcels sold								3
Capital balance	1,863,172,000					1,826,954,000		1,863,172,000			22,000,000
Closing costs						26,136,000		22,716,000		3,746,000
Closing prorations and related adjustments								535,000
Realized gains (losses) on sales, net	-1,559,000	[6]	47,321,000		13,758,000			59,520,000		-13,175,000
22 Sylvan Way [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1
Rentable Square Feet						249,409
Net Sales Proceeds						94,897,000
Net Book Value						60,244,000
Realized Gain (loss)						34,653,000
30 Knightsbridge Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						4	[7]
Rentable Square Feet						680,350
Net Sales Proceeds						54,641,000
Net Book Value						52,361,000
Realized Gain (loss)						2,280,000
470 Chestnut Ridge Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1	[7],[8]
Rentable Square Feet						52,500	[7],[8]
Net Sales Proceeds						7,195,000	[7],[8]
Net Book Value						7,109,000	[7],[8]
Realized Gain (loss)						86,000	[7],[8]
530 Chestnut Ridge Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1	[7],[8]
Rentable Square Feet						57,204	[7],[8]
Net Sales Proceeds						6,299,000	[7],[8]
Net Book Value						6,235,000	[7],[8]
Realized Gain (loss)						64,000	[7],[8]
400 Rella Boulevard [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1
Rentable Square Feet						180,000
Net Sales Proceeds						27,539,000
Net Book Value						10,938,000
Realized Gain (loss)						16,601,000
412 Mt. Kemble Avenue [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1	[7]
Rentable Square Feet						475,100	[7]
Net Sales Proceeds						44,751,000	[7]
Net Book Value						43,851,000	[7]
Realized Gain (loss)						900,000	[7]
17-17 Rte 208 North [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1	[7],[8]
Rentable Square Feet						143,000	[7],[8]
Net Sales Proceeds						11,835,000	[7],[8]
Net Book Value						11,731,000	[7],[8]
Realized Gain (loss)						104,000	[7],[8]
555, 565, 570 Taxter Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						3	[7]
Rentable Square Feet						416,108	[7]
Net Sales Proceeds						41,057,000	[7]
Net Book Value						41,057,000	[7]
200, 220 White Plains Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						2	[7]
Rentable Square Feet						178,000	[7]
Net Sales Proceeds						12,619,000	[7]
Net Book Value						12,619,000	[7]
1266 East Main Street [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings						1	[7],[8]
Rentable Square Feet						179,260	[7],[8]
Net Sales Proceeds						18,406,000	[7],[8]
Net Book Value						18,246,000	[7],[8]
Realized Gain (loss)						160,000	[7],[8]
Keystone Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds						196,800,000
Sale price of property						221,000,000
Sale price of property, cash						192,500,000
Sale price of property, capital accounts						21,200,000
Closing costs paid						3,000,000
Ownership interest						0.00%
Number of properties with senior pari passu interest						5
Sale price of property, capital balance in properties in which senior pari passu interest is held						7,300,000
Impairment charge								20,800,000
Keystone Portfolio [Member] | Keystone Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Internal rate of return						15.00%
Keystone Portfolio [Member] | Parent Company [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Internal rate of return						10.00%
19 Skyline Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1	[9]						1	[9]
Rentable Square Feet								248,400	[9]	248,400
Net Sales Proceeds								16,131,000	[9]
Net Book Value	16,005,000	[9]						16,005,000	[9]
Realized Gain (loss)								126,000	[9]
Valuation allowance										7,100,000
Note receivable	5,000,000							5,000,000
Note receivable, net present value	3,700,000							3,700,000
55 Corporate Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1							1
Rentable Square Feet								204,057		204,057
Net Sales Proceeds								70,967,000
Net Book Value	51,308,000							51,308,000
Realized Gain (loss)								19,659,000
200 Riser Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1							1
Rentable Square Feet								286,628
Net Sales Proceeds								31,775,000
Net Book Value	14,852,000							14,852,000
Realized Gain (loss)								16,923,000
777 Passaic Avenue [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1							1
Rentable Square Feet								75,000
Net Sales Proceeds								5,640,000
Net Book Value	3,713,000							3,713,000
Realized Gain (loss)								1,927,000
16 And 18 Sentry Parkway West [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	2	[10]						2	[10]
Rentable Square Feet								188,103	[10]
Net Sales Proceeds								19,041,000	[10]
Net Book Value	19,721,000	[10]						19,721,000	[10]
Realized Gain (loss)								-680,000	[10]
Impairment charge										8,400,000
51 Imclone Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1	[11]						1	[11]
Rentable Square Feet								63,213	[11]
Net Sales Proceeds								6,101,000	[11]
Net Book Value	5,278,000	[11]						5,278,000	[11]
Realized Gain (loss)								823,000	[11]
40 Richards Avenue [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1							1
Rentable Square Feet								145,487
Net Sales Proceeds								15,858,000
Net Book Value	17,027,000							17,027,000
Realized Gain (loss)								-1,169,000
106 Allen Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	1							1
Rentable Square Feet								132,010
Net Sales Proceeds								17,677,000
Net Book Value	15,081,000							15,081,000
Realized Gain (loss)								2,596,000
Pennsylvania Office Portfolio [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of Buildings	15	[12],[13]						15	[12],[13]
Rentable Square Feet								1,663,511	[12],[13]
Net Sales Proceeds								207,425,000	[12],[13]
Net Book Value	164,259,000	[12],[13]						164,259,000	[12],[13]
Realized Gain (loss)								43,166,000	[12],[13]
Sale price of property											233,000,000
Sale price of property, cash											201,000,000
Impairment charge								23,851,000
Number of impaired properties								5
Number of land parcels sold											3
Amount held by intermediary for reinvestment	55,300,000							55,300,000
New mortgage loan											10,000,000
Number of mortgage loans											1
Amount of mortgage funded											8,000,000
Closing costs											$4,000,000
Mortgage loan, maturity period											2 years
Loan extension period											1 year
Spread over LIBOR											6.00%
Subordinated equity internal rate of return											10.00%
Pennsylvania Office Portfolio [Member] | Keystone Entities [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Third party ownership percentage	0.00%							0.00%
Senior equity internal rate of return											15.00%
[1]	This amount excludes approximately $535,000 of net closing prorations and related adjustments received from sellers at closing.
[2]	This amount, net of impairment charges recorded in 2013 of $23,851,000 on certain of the properties prior to their sale (per Note [d] above), comprises the $59,520,000 of realized gains (losses) and unrealized losses on disposition of rental property and impairments, net, for the year ended December 31, 2013.B See Note 7: Discontinued Operations.
[3]	Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions - Impairments on Properties Held and Used.
[4]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[5]	Includes as of December 31, 2014: a mortgage receivable for $10.4 million which bears interest at LIBOR plus six percent and matures in August 2015; a note receivable for $7.8 million which bears interest at eight percent and matures in October 2017; and an interest-free note receivable with a net present value of $3.3 million and matures in April 2023. The Company believes these balances are fully collectable.
[6]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[7]	The Company completed the sale of these properties for approximately $221 million comprised of: $192.5 million in cash from a combination of affiliates of Keystone Property Group (bKeystone Entitiesb) senior and pari-passu equity and mortgage financing; Company subordinated equity interests in each of the properties sold with capital accounts aggregating $21.2 million and Company pari-passu equity interests in five of the properties sold aggregating $7.3 million. Net sale proceeds from the sale aggregated $196.8 million which was comprised of the $221 million gross sales price less the subordinated equity interests of $21.2 million and $3 million in closing costs. The purchasers of these properties are unconsolidated joint ventures formed between the Company and the Keystone Entities. The senior and pari-passu equity will receive a 15 percent internal rate of return (bIRRb) after which the subordinated equity will receive a 10 percent IRR and then all distributable cash flow will be split equally between the Keystone Entities and the Company. See Note 4: Investments in Unconsolidated Joint Ventures. In connection with certain of these partial sale transactions, because the buyer received a preferential return on certain of the ventures for which the Company received subordinated equity interests, the Company only recognized profit to the extent that they received net proceeds in excess of their entire carrying value of the properties, effectively reflecting their retained subordinated equity interest at zero.
[8]	The Company recorded an impairment charge of $20.8 million on these properties at December 31, 2013 as it estimated that the carrying value of the properties may not be recoverable over their anticipated holding periods.
[9]	The Company recognized a valuation allowance of $7.1 million on this property identified as held for sale at December 31, 2012. In connection with the sale, the Company provided an interest-free note receivable to the buyer of $5 million (with a net present value of $3.7 million at closing) which matures in 2023 and requires monthly payments of principal. See Note 5: Deferred charges, goodwill and other assets.
[10]	The Company recorded an $8.4 million impairment charge on these properties at December 31, 2012. The Company has retained a subordinated interest in these properties.
[11]	The property was encumbered by a mortgage loan which was satisfied by the Company at the time of the sale. The Company incurred $0.7 million in costs for the debt satisfaction, which was included in discontinued operations: loss from early extinguishment of debt for the year ended December 31, 2013.
[12]	In order to reduce the carrying value of five of the properties to their estimated fair market values, the Company recorded impairment charges of $23,851,000 at June 30, 2013. The fair value used in the impairment charges was based on the purchase and sale agreement for the properties ultimately sold.
[13]	The Company completed the sale of this office portfolio and three developable land parcels for approximately $233 million: $201 million in cash ($55.3 million of which was held by a qualified intermediary until such funds were used in acquisitions), a $10 million mortgage on one of the properties ($8 million of which was funded at closing) and subordinated equity interests in each of the properties being sold with capital accounts aggregating $22 million. Net sale proceeds from the sale aggregated $207 million which was comprised of the $233 million gross sales price less the subordinated equity interests of $22 million and $4 million in closing costs. The purchasers of the Pennsylvania office portfolio are joint ventures formed between the Company and affiliates of the Keystone Property Group (the bKeystone Affiliatesb). The mortgage loan has a term of two years with a one year extension option and bears interest at LIBOR plus six percent. The Company's equity interests in the joint ventures will be subordinated to Keystone Affiliates receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a ten percent IRR on its subordinated equity and then all profit will be split equally. In connection with these partial sale transactions, because the buyer receives a preferential return, the Company only recognized profit to the extent that they received net proceeds in excess of their entire carrying value of the properties, effectively reflecting their retained subordinate equity interest at zero. As part of the transaction, the Company has rights to own, after zoning-approval-subdivision, land at the 150 Monument Road property located in Bala Cynwyd, Pennsylvania, for a contemplated multi-family residential development.

Real_Estate_Transactions_Summa

Real Estate Transactions (Summary Of Income From Property Held For Sale) (Details) (USD $)	3 Months Ended						12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014
Real Estate Properties [Line Items]
Total revenues							$33,601,000	$66,882,000
Operating and other expenses							-13,454,000	-26,484,000
Depreciation and amortization							-8,218,000	-17,765,000
Income from properties sold	-9,000		2,157,000		4,530,000	5,133,000	11,811,000	21,878,000
Impairments	62,153,000	[1],[2]	48,700,000	[1]			110,853,000	9,845,000
Realized gains (losses) on sales, net	-1,559,000	[3]	47,321,000		13,758,000		59,520,000	-13,175,000
Total discontinued operations, net	-1,568,000		49,478,000		17,585,000	5,133,000	70,628,000	8,703,000
Properties Sold, Year To Date [Member]
Real Estate Properties [Line Items]
Total revenues							55,677,000	54,753,000	28,823,000
Operating and other expenses							-27,993,000	-25,142,000	-17,248,000
Depreciation and amortization							-15,061,000	-14,522,000	-6,371,000
Interest income								-615,000	4,000
Income from properties sold							12,623,000	14,474,000	5,208,000
Impairments							-20,761,000
Realized gains (losses) on sales, net									54,848,000
Total discontinued operations, net							($8,138,000)	$14,474,000	$60,056,000
[1]	Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions - Impairments on Properties Held and Used.
[2]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[3]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.

Investments_In_Unconsolidated_2

Investments In Unconsolidated Joint Ventures (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
	entity
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	$247,468,000		$181,129,000
Percentage of interest in venture		[1],[2],[3]
Management, leasing, development and other services fees	6,200,000		5,800,000
Accounts receivable from unconsolidated joint ventures	1,000,000		523,000
Number of VIEs	9
Maximum exposure to loss	230,500,000
Estimated future funding commitments	116,900,000
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	477,000,000
Outstanding borrowings under the facility	238,000,000
Unconsolidated Joint Venture Multi-Family Properties [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties	13
Number of units	4,183
Unconsolidated Joint Venture Retail Buildings [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties	2
Area of property (in square feet)	81,500
Unconsolidated Joint Venture Land Parcels [Member]
Schedule of Equity Method Investments [Line Items]
Area of property (in square feet)	1,400,000
Number of units	2,853
Unconsolidated Joint Venture Office Buildings [Member]
Schedule of Equity Method Investments [Line Items]
Number of properties	36
Unconsolidated Joint Venture Office And Retail Buildings [Member]
Schedule of Equity Method Investments [Line Items]
Area of property (in square feet)	5,600,000
Unconsolidated Joint Venture Development Projects [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	1,731
Unconsolidated Joint Venture Hotel [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	350
Parent Company [Member] | Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	93,500,000
Outstanding borrowings under the facility	62,600,000
Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	7.50%
Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	85.00%
Variable Interest Entity [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	113,600,000
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	350
Percentage of interest in venture	50.00%	[1]
Letter of credit	$4,100,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).

Investments_In_Unconsolidated_3

Investments In Unconsolidated Joint Ventures (Recent Transactions) (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	21-May-14
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	$247,468,000		$181,129,000
Development of rental property	25,140,000		13,772,000	60,354,000
Percentage of interest in venture		[1],[2],[3]
Interest rate
Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of capital event cash flows distributed	50.00%
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	763	[4]
Percentage of interest in venture	85.00%
Investments in unconsolidated joint ventures	34,954,000	[4]			30,600,000
Capital credit receivable per developable square foot	30
Aggregate capital credits	20,600,000
Development of rental property	19,200,000
Percentage of interest in venture	85.00%	[1],[4]
Interest rate	5.20%	[4],[5]
Holding and distribution pattern under operating agreement	In general, the operating agreement of URL-Harborside provides that net operating cash flows are distributed first, to the members in respect of preferred return, as defined, until each member shall have received payment of the accrued and unpaid preferred return; and, thereafter, 75 percent to the Company and 25 percent to ISA.
Harborside Unit A Urban Renewal, LLC [Member] | Construction Loan [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	192,000,000
Harborside Unit A Urban Renewal, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of operating return on capital	75.00%
Internal rate of return	18.00%
Percentage of capital event cash flows distributed after initial internal rate of return reached	65.00%
Percentage of capital event cash flows distributed	75.00%
Harborside Unit A Urban Renewal, LLC [Member] | Ironstate Harborside-A, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	5,400,000
Percentage of operating return on capital	25.00%
Percentage of capital event cash flows distributed after initial internal rate of return reached	35.00%
Percentage of capital event cash flows distributed	25.00%
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	59,911,000	[6]
Percentage of interest in venture	50.00%	[1],[6]
Area of property (in square feet)	885,000	[6]
KPG-MCG Curtis JV, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%
KPG-MCG Curtis JV, LLC [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%
Harborside Residential Project [Member] | Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	763
Total project costs	320,000,000
State tax credit	33,000,000
Harborside Residential Project [Member] | Harborside Unit A Urban Renewal, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Total project costs	59,100,000
Curtis Center Property [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	125,000,000
Curtis Center Property [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	62,500,000
Percentage of interest in venture	50.00%
Curtis Center Property [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	62,500,000
Percentage of interest in venture	50.00%
Land [Member] | Harborside Unit A Urban Renewal, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	$5,500,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).
[4]	See discussion Unconsolidated Joint Venture Transactions following in this footnote.
[5]	The construction/permanent loan has a maximum borrowing amount of $192,000.
[6]	Includes undivided interests in the same manner as investments in noncontrolling partnership, pursuant to ASC 970-323-25-12. See discussion in Unconsolidated Joint Venture Transactions following in this footnote.

Investments_In_Unconsolidated_4

Investments In Unconsolidated Joint Ventures (Summary Of Unconsolidated Joint Ventures) (Details) (USD $)	12 Months Ended				0 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Aug. 15, 2014	Mar. 20, 2013	Sep. 02, 2013	Jun. 30, 2013	Dec. 26, 2014	Dec. 23, 2013	21-May-14
Schedule of Equity Method Investments [Line Items]
Company's Effective Ownership %		[1],[2],[3]
Company's Carrying Amount	$247,468,000		$181,129,000
Property Debt, Balance	1,673,364,000
Property Debt, Interest Rate
Number of units available for development						295
Number of approved units available for development						252
Sales proceeds	319,239,000		390,615,000	[4]
Accounts payable, accrued expenses and other liabilities	126,971,000		121,286,000
Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Company's Effective Ownership %	7.50%
Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Company's Effective Ownership %	85.00%
Multi-Family Properties [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	5,484
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	412
Company's Effective Ownership %	24.27%	[1]
Company's Carrying Amount	15,779,000		15,797,000
Property Debt, Balance	95,000,000
Property Debt, Maturity Date	1-May-18
Property Debt, Interest Rate	4.99%
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	523	[5]
Company's Effective Ownership %	15.00%	[1],[5]
Company's Carrying Amount	2,161,000	[5]	3,201,000	[5]
Property Debt, Balance	165,000,000	[5]
Property Debt, Maturity Date	1-Feb-21	[5]
Property Debt, Interest Rate	4.19%	[5]
Rosewood Lafayette Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	217	[5]
Company's Effective Ownership %	25.00%	[1],[5]
Company's Carrying Amount	62,000	[5]	857,000	[5]
Property Debt, Balance	38,665,000	[5]
Property Debt, Maturity Date	1-Jul-15	[5]
Property Debt, Interest Rate	4.00%	[5]
PruRose Port Imperial South 15, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	236
Company's Effective Ownership %	50.00%	[1]
Property Debt, Balance	57,500,000
Property Debt, Maturity Date	1-Sep-20
Property Debt, Interest Rate	4.32%
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	130	[6],[7]
Company's Effective Ownership %	12.50%	[1],[6],[7]
Company's Carrying Amount	6,029,000	[6],[7]	6,455,000	[6],[7]
Property Debt, Balance	46,217,000	[6],[7],[8]
Note payable	975,000
Overlook Ridge JV, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	251
Company's Effective Ownership %	50.00%	[1]
Property Debt, Balance	69,501,000	[9]
Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	371	[10]
Company's Effective Ownership %	50.00%	[1],[10]
Company's Carrying Amount	2,524,000	[10]
Property Debt, Balance	49,824,000	[10]
Property Debt, Maturity Date	26-Dec-15	[10]
Property Debt, Interest Rate, LIBOR	L+2.50	[10],[11]
Cash consideration					2,970,000
PruRose Riverwalk G, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	316
Company's Effective Ownership %	25.00%	[1]
Company's Carrying Amount	955,000		3,117,000
Property Debt, Balance	79,594,000
Property Debt, Maturity Date	15-Jul-21
Property Debt, Interest Rate	6.00%	[12]
PruRose Riverwalk G, L.L.C. [Member] | Construction Loan [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	83,113,000
PruRose Riverwalk G, L.L.C. [Member] | Permanent Loan [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity									80,249,000
Elmajo Urban Renewal Associates, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	355
Company's Effective Ownership %	7.50%	[1]
Company's Carrying Amount			203,000
Property Debt, Balance	81,264,000
Property Debt, Maturity Date	27-Jun-16
Property Debt, Interest Rate, LIBOR	L+2.10	[13]
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	828	[14]				828
Company's Effective Ownership %	25.00%	[1],[14]				25.00%
Company's Carrying Amount	27,051,000	[14]	26,838,000	[14]
Property Debt, Balance	165,000,000	[14]
Property Debt, Maturity Date	1-Apr-20	[14]
Property Debt, Interest Rate	3.17%	[14]
Cash consideration						30,200,000
Percentage of interest in developable land	50.00%					50.00%
Number of units available for development	295
Number of approved units available for development	252
Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	176
Company's Effective Ownership %	38.25%	[1]
Company's Carrying Amount	1,747,000		3,207,000
Property Debt, Balance	37,093,000
Property Debt, Maturity Date	4-Dec-15
Property Debt, Interest Rate, LIBOR	L+2.50	[15]
PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	280
Company's Effective Ownership %	20.00%	[1]
Company's Carrying Amount	1,087,000		2,206,000
Property Debt, Balance	49,084,000
Property Debt, Maturity Date	27-Jun-16
Property Debt, Interest Rate, LIBOR	L+2.15	[16]
Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	363	[17],[5]
Company's Effective Ownership %	20.00%	[1],[17],[5]
Company's Carrying Amount	1,800,000	[17],[5]	2,068,000	[17],[5]
RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	311
Company's Effective Ownership %	24.27%	[1]
Company's Carrying Amount	11,282,000		7,567,000
Property Debt, Balance	31,564,000
Property Debt, Maturity Date	30-Mar-17
Property Debt, Interest Rate, LIBOR	L+2.25	[18]
Estuary Urban Renewal Unit B, LLC [Member
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	227
Company's Effective Ownership %	7.50%	[1]
Company's Carrying Amount			24,000
Property Debt, Balance	40,366,000
Property Debt, Maturity Date	25-Jan-17
Property Debt, Interest Rate, LIBOR	L+2.10	[19]
Riverpark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	141
Company's Effective Ownership %	36.00%	[1]
Company's Carrying Amount	4,744,000		3,655,000
Property Debt, Balance	21,298,000
Property Debt, Maturity Date	27-Jun-16
Property Debt, Interest Rate, LIBOR	L+2.35	[20]
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	377
Company's Effective Ownership %	50.00%	[1]								50.00%
Company's Carrying Amount	49,327,000		46,628,000							46,500,000
Property Debt, Balance	73,971,000
Property Debt, Maturity Date	1-Jul-33
Property Debt, Interest Rate	4.82%	[21]
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	763	[22]
Company's Effective Ownership %	85.00%	[1],[22]
Company's Carrying Amount	34,954,000	[22]									30,600,000
Property Debt, Maturity Date	1-Aug-29	[22]
Property Debt, Interest Rate	5.20%	[22],[23]
Harborside Unit A Urban Renewal, LLC [Member] | Construction Loan [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	192,000,000
Harborside Unit A Urban Renewal, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Internal rate of return	18.00%
RoseGarden Monaco, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	300
Company's Effective Ownership %	41.67%	[1]
Company's Carrying Amount	1,283,000		1,224,000
Property Debt, Interest Rate, LIBOR	-
Grand Jersey Waterfront Urban Renewal Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	1,000
Company's Effective Ownership %	50.00%	[1]
Company's Carrying Amount	337,000		337,000
Red Bank Corporate Plaza, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	92,878
Company's Effective Ownership %	50.00%	[1]
Company's Carrying Amount	3,963,000		4,046,000
Property Debt, Balance	15,868,000
Property Debt, Maturity Date	17-May-16
Property Debt, Interest Rate	3.99%
Property Debt, Interest Rate, LIBOR	L+3.00	[24]
Notional amount	13,650,000
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	139,750
Company's Effective Ownership %	50.00%	[1]
Company's Carrying Amount	5,620,000		5,514,000
Property Debt, Balance	14,002,000
Property Debt, Maturity Date	1-Jul-23
Property Debt, Interest Rate	2.87%
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	106,345
Company's Effective Ownership %	31.25%	[1]
Company's Carrying Amount	1,993,000		1,753,000
Property Debt, Balance	6,756,000
Property Debt, Maturity Date	1-Nov-23
Property Debt, Interest Rate	4.76%
Hillsborough 206 Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	160,000
Company's Effective Ownership %	50.00%	[1]
Company's Carrying Amount	1,962,000		1,962,000
KPG-P 100 IMW JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	339,615
Company's Effective Ownership %	33.33%	[1]	57.77%
Company's Carrying Amount			1,887,000
Property Debt, Balance	61,500,000
Property Debt, Maturity Date	9-Sep-16
Property Debt, Interest Rate, LIBOR	L+7.00	[25]
Number of stories	9
Cash consideration	40,500,000
Number of extension options	2
Loan extension period	1 year
Outstanding borrowings under the facility	15,800,000
Construction reserve	25,000,000
Keystone-Penn [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	1,842,820
Company's Effective Ownership %
Property Debt, Balance	203,811,000	[26]
Keystone-Penn [Member] | Principal Balance Due August 27, 2023 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	127,600,000
Property Debt, Maturity Date	27-Aug-23
Property Debt, Interest Rate	5.11%
Keystone-Penn [Member] | Principal Balance Due August 27, 2016 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	65,786,000
Property Debt, Maturity Date	27-Aug-16
Keystone-Penn [Member] | Principal Balance Due August 27, 2016 [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Interest Rate, LIBOR	LIBOR+5.0
Property Debt, Interest Rate, Spread Over LIBOR	5.00%
Keystone-Penn [Member] | Principal Balance Due August 27, 2016 [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Interest Rate, LIBOR	LIBOR+5.75
Property Debt, Interest Rate, Spread Over LIBOR	5.75%
Keystone-Penn [Member] | Principal Balance Due August 27, 2015 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	10,425,000
Property Debt, Maturity Date	27-Aug-15
Property Debt, Interest Rate, LIBOR	LIBOR+6.0
Property Debt, Interest Rate, Spread Over LIBOR	6.00%
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	1,266,384
Company's Effective Ownership %
Company's Carrying Amount	6,140,000
Property Debt, Balance	204,843,000	[27]
Property Debt, Interest Rate
Sale price of property, capital balance in properties in which senior pari passu interest is held	6,200,000
Number of properties with senior pari passu interest	5
Keystone-TriState [Member] | Principal Balance Due July 1, 2017 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	41,240,000
Property Debt, Maturity Date	1-Jul-17
Property Debt, Interest Rate, LIBOR	4.95
Property Debt, Interest Rate, Spread Over LIBOR	4.95%
Keystone-TriState [Member] | Principal Balance Due September 9th, 2017 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	70,903,000
Property Debt, Maturity Date	9-Sep-17
Bears interest at fixed rate range, minimum	5.65%
Bears interest at fixed rate range, maximum	6.75%
Keystone-TriState [Member] | Principal Balance Due July 6, 2024 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	14,250,000
Property Debt, Maturity Date	6-Jul-24
Property Debt, Interest Rate	4.88%
Keystone-TriState [Member] | Principal Balance Due July 6, 2044 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	63,400,000
Property Debt, Maturity Date	6-Jul-44
Property Debt, Interest Rate	4.93%
Keystone-TriState [Member] | Principal Balance Due August 6, 2044 [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	15,050,000
Property Debt, Maturity Date	6-Aug-44
Property Debt, Interest Rate	4.71%
Keystone-TriState [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Internal rate of return	10.00%
Keystone-TriState [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Internal rate of return	15.00%
Keystone-Penn And Keystone-TriState [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Internal rate of return	15.00%
Keystone-Penn And Keystone-TriState [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Internal rate of return	10.00%
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	885,000	[28]
Company's Effective Ownership %	50.00%	[1],[28]
Company's Carrying Amount	59,911,000	[28]
Property Debt, Balance
KPG-MCG Curtis JV, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Company's Effective Ownership %	50.00%
KPG-MCG Curtis JV, LLC [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Company's Effective Ownership %	50.00%
Plaza VIII & IX Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	1,225,000
Company's Effective Ownership %	50.00%	[1]
Company's Carrying Amount	4,022,000		3,702,000
Roseland/North Retail, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	30,745	[5]
Company's Effective Ownership %	20.00%	[1],[5]
Company's Carrying Amount	1,828,000	[5]	1,930,000	[5]
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	350
Company's Effective Ownership %	50.00%	[1]
Property Debt, Balance	65,643,000	[29]
Property Debt, Maturity Date	1-Aug-20
Property Debt, Interest Rate
Note payable	4,100,000
Bears interest at fixed rate range, minimum	6.09%
Bears interest at fixed rate range, maximum	6.62%
Letter of credit	4,100,000
Accounts payable, accrued expenses and other liabilities	1,854,000		1,706,000
South Pier At Harborside [Member] | Hotel [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	61,519,000
Property Debt, Maturity Date	1-Nov-16
Property Debt, Interest Rate	6.15%
Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's Effective Ownership %	80.00%	[1],[30]
Company's Carrying Amount			36,258,000	[30]
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's Carrying Amount	907,000	[31]	693,000	[31]
The Shops At 40 Park Property [Member] | Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Square Feet	50,973
Property Debt, Balance	6,500,000
Property Debt, Maturity Date	1-Aug-18
Property Debt, Interest Rate	3.63%
Residual ownership interest	12.50%
Lofts At 40 Park Property [Member] | Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	59
Property Debt, Balance	1,117,000
Property Debt, Maturity Date	1-Sep-15
Property Debt, Interest Rate, Spread Over LIBOR	2.50%
Indirect ownership interest	25.00%
Number of stories	5
Additional borrowing capacity	1,000,000
Metropolitan Property [Member] | Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	38,600,000
Property Debt, Maturity Date	1-Sep-20
Property Debt, Interest Rate	3.25%
Port Imperial North Land [Member] | Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Number of Apartment Units	836
Residual ownership interest	20.00%
Senior Loans [Member] | Quarrystone I Property [Member] | Overlook Ridge JV, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	52,501,000
Property Debt, Maturity Date	1-Mar-16
Property Debt, Interest Rate, Spread Over LIBOR	2.00%
Junior Loans [Member] | Quarrystone I Property [Member] | Overlook Ridge JV, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Balance	17,000,000
Property Debt, Maturity Date	1-Mar-16
Property Debt, Interest Rate, Spread Over LIBOR	0.90%
Letter of Credit [Member] | Quarrystone I Property [Member] | Overlook Ridge JV, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	17,000,000
Construction Loan [Member] | Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Interest Rate	3.09%
Number of extension options	2
Loan extension period	1 year
Maximum borrowing capacity	55,500,000
Notional amount	52,000,000						1,840,000
Construction Loan [Member] | Elmajo Urban Renewal Associates, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Loan extension period	1 year
Extension fee	0.25%
Maximum borrowing capacity	91,000,000
Construction Loan [Member] | Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of extension options	2
Loan extension period	2 years
Maximum borrowing capacity	42,500,000
Construction Loan [Member] | PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Interest Rate	2.79%
Maximum borrowing capacity	73,350,000
Notional amount	69,500,000							1,620,000
Construction Loan [Member] | RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of extension options	2
Loan extension period	1 year
Maximum borrowing capacity	77,400,000
Construction Loan [Member] | Estuary Urban Renewal Unit B, LLC [Member
Schedule of Equity Method Investments [Line Items]
Loan extension period	1 year
Extension fee	0.25%
Maximum borrowing capacity	57,000,000
Construction Loan [Member] | Riverpark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Number of extension options	2
Loan extension period	1 year
Maximum borrowing capacity	23,400,000
Construction Loan [Member] | Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity	100,700,000
Construction Loan Extension Number 1 [Member] | Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.25%
Construction Loan Extension Number 1 [Member] | Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.13%
Construction Loan Extension Number 1 [Member] | PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Loan extension period	1 year
Extension fee	0.25%
Construction Loan Extension Number 1 [Member] | RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.25%
Construction Loan Extension Number 1 [Member] | Riverpark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.20%
Construction Loan Extension Number 2 [Member]
Schedule of Equity Method Investments [Line Items]
Loan extension period	2 years
Construction Loan Extension Number 2 [Member] | Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.25%
Construction Loan Extension Number 2 [Member] | Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.25%
Construction Loan Extension Number 2 [Member] | PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Loan extension period	6 months
Extension fee	0.25%
Construction Loan Extension Number 2 [Member] | RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.25%
Construction Loan Extension Number 2 [Member] | Riverpark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Extension fee	0.20%
Mezz Loan [Member] | Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Sales proceeds	47,200,000
Mezz Loan [Member] | Stamford SM LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Sales proceeds	37,800,000
Overlook Ridge Properties [Member]
Schedule of Equity Method Investments [Line Items]
Cash consideration					16,600,000
Overlook Ridge Properties [Member] | Multi-Family Properties [Member]
Schedule of Equity Method Investments [Line Items]
Indirect ownership interest					50.00%
Number of properties in which additional interest was acquired during period					2
Overlook Ridge Properties [Member] | Consolidated Land [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in developable land					100.00%
Overlook Ridge Properties [Member] | Consolidated Land [Member] | Minimum [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Interest Rate, Spread Over LIBOR					2.50%
Overlook Ridge Properties [Member] | Consolidated Land [Member] | Maximum [Member]
Schedule of Equity Method Investments [Line Items]
Property Debt, Interest Rate, Spread Over LIBOR					3.50%
LR Overlook Phase III, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Cash consideration					600,000
Overlook Ridge, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Cash consideration					$12,990,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).
[4]	This amount excludes approximately $535,000 of net closing prorations and related adjustments received from sellers at closing.
[5]	The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the Company is not expected to meaningfully participate in the venture's cash flows in the near term.
[6]	Through the joint venture, the Company also owns a 12.5 percent interest in a 50,973 square feet retail building ("Shops at 40 Park") and a 25 percent interest in a to-be-built 59-unit, five story multi-family rental development property ("Lofts at 40 Park").
[7]	The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the payment of the outstanding balance remaining on a note ($975 as of December 31, 2014), and is not expected to meaningfully participate in the venture's cash flows in the near term.
[8]	Property debt balance consists of: (i) a loan, collateralized by the Metropolitan at 40 Park, with a balance of $38,600 at December 31, 2014, bears interest at 3.25 percent, matures in September 2020 and is interest only through September 2015; (ii) a loan, collateralized by the Shops at 40 Park, with a balance of $6,500 at December 31, 2014, bears interest at 3.63 percent, matures in August 2018 and is interest-only through July 2015; and (iii) a loan, collateralized by the Lofts at 40 Park, with a balance of $1,117, bears interest at LIBOR plus 250 basis points and matures in September 2015. The Shops at 40 Park mortgage loan also provides for additional borrowing proceeds of $1 million based on certain preferred thresholds being achieved.
[9]	Property debt balance consists of: (i) the senior loan, collateralized by the Quarrystone property, with a balance of $52,501 at December 31, 2014, bears interest at LIBOR plus 200 basis, matures in March 2016 and (ii) the junior loan, with a balance of $17,000, bears interest at LIBOR plus 90 basis points, matures in March 2016 and is collateralized by a $17,000 letter of credit provided by an affiliate of the partner.
[10]	On August 15, 2014, the Company acquired the equity interests of its joint venture partner in Overlook Ridge JV 2C/3B, L.L.C. for $2.97 million and LR Overlook Phase II, L.L.C., the property-owning entity owned by Overlook Ridge JV, L.L.C., which increased its ownership to 50 percent in two operating multi-family properties. The Company also acquired the equity interests of its joint venture partner in LR Overlook Phase III, L.L.C. and Overlook Ridge, L.L.C. for $0.6 million and $12.99 million respectively, which increased its ownership to 100 percent in developable land (See Note 3: Real Estate Transactions - Acquisitions).
[11]	The construction loan has a maximum borrowing amount of $55,500 and provides, subject to certain conditions, two one-year extension options with a fee of 25 basis points each. The joint venture has a swap agreement that fixes the all-in rate to 3.0875 percent per annum on an initial notional amount of $1,840, increasing to $52,000, for the period from September 3, 2013 to November 2, 2015.
[12]	The construction loan with a maximum borrowing amount of $83,113 was converted to a permanent loan on December 26,2014 with a maximum borrowing amount of $80,249
[13]	The construction loan has a maximum borrowing amount of $91,000 and provides, subject to certain conditions, a one-year extension option with a fee of 25 basis points.
[14]	The Company also owns a 50 percent interest in a vacant land parcel to accommodate the development of approximately 295 additional units of which 252 are currently approved.
[15]	The construction loan has a maximum borrowing amount of $42,500 and provides, subject to certain conditions, two two-year extension options with a fee of 12.5 basis points for the first two-year extension and 25 basis points for the second two-year extension.
[16]	The construction loan has a maximum borrowing amount of $73,350 and provides, subject to certain conditions, one-year extension option followed by a six-month extension option with a fee of 25 basis points each. The joint venture has a swap agreement that fixes the all-in rate to 2.79 percent per annum on an initial notional amount of $1,620, increasing to $69,500 for the period from July 1, 2013 to January 1, 2016.
[17]	The Company also owns a 20 percent residual interest in undeveloped land parcels: parcels 6, I, and J ("Port Imperial North Land") that can accommodate the development of 836 apartment units.
[18]	The construction loan has a maximum borrowing amount of $77,400 and provides, subject to certain conditions, two one-year extension options with a fee of 25 basis points for each year.
[19]	The construction loan has a maximum borrowing amount of $57,000 and provides, subject to certain conditions, a one-year extension option with a fee of 25 basis points.
[20]	The construction loan has a maximum borrowing amount of $23,400 and provides, subject to certain conditions, two one-year extension options with a fee of 20 basis points for each year.
[21]	The construction/permanent loan has a maximum borrowing amount of $100,700 with amortization starting in August 2017.
[22]	See discussion Unconsolidated Joint Venture Transactions following in this footnote.
[23]	The construction/permanent loan has a maximum borrowing amount of $192,000.
[24]	The joint venture has a swap agreement that fixes the all-in rate to 3.99375 percent per annum on an initial notional amount of $13,650 and then adjusting in accordance with an amortization schedule, which is effective from October 17, 2011 through loan maturity.
[25]	The mortgage loan has two one-year extension options, subject to certain conditions, and includes a $25 million construction escrow with a balance of $15.8 million to be drawn at December 31, 2014.
[26]	Principal balance of $127,600 bears interest at 5.114 percent and matures in August 27, 2023; principal balance of $65,786 bears interest at rates ranging from LIBOR+5.0 percent to LIBOR+5.75 percent and matures in August 27, 2016; principal balance of $10,425 bears interest at LIBOR+6.0 percent matures in AugustB 27, 2015.
[27]	Principal balance of $41,240 bears interest at 4.95 percent and matures on July 1, 2017; principal balance of $70,903 bears interest at rates ranging from 5.65 percent to 6.75 percent and matures on September 9, 2017; principal balance of $14,250 bears interest at 4.88 percent and matures on July 6, 2024; principal balance of $63,400 bears interest at 4.93 percent and matures on July 6, 2044; principal balance of $15,050 bears interest at 4.71 percent and matures on August 6, 2044.
[28]	Includes undivided interests in the same manner as investments in noncontrolling partnership, pursuant to ASC 970-323-25-12. See discussion in Unconsolidated Joint Venture Transactions following in this footnote.
[29]	Balance includes: (i) mortgage loan, collateralized by the hotel property, with a balance of $61,519, bears interest at 6.15 percent and matures in November 2016, and (ii) loan with a balance of $4.1 million, bears interest at fixed rates ranging from 6.09 percent to 6.62 percent and matures in August 1, 2020. The Company posted a $4.1 million letter of credit in support of this loan, half of which is indemnified by the partner.
[30]	The joint venture collected net proceeds of $47.2 million at maturity, of which the Company received its share of $37.8 million on August 6, 2014.
[31]	The Company owns other interests in various unconsolidated joint ventures, including interests in assets previously owned and interest in ventures whose businesses are related to its core operations. These ventures are not expected to significantly impact the Company's operations in the near term.

Investments_In_Unconsolidated_5

Investments In Unconsolidated Joint Ventures (Summary Of Financial Position Of Unconsolidated Joint Ventures) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments In Unconsolidated Joint Ventures [Abstract]
Rental property, net	$1,534,812	$755,038
Loan receivable		45,050
Other assets	398,173	582,989
Total assets	1,932,985	1,383,077
Mortgages and loans payable	1,060,020	637,709
Other liabilities	211,340	87,231
Partners'/members' capital	661,625	658,137
Total liabilities and partners'/members' capital	$1,932,985	$1,383,077

Investments_In_Unconsolidated_6

Investments In Unconsolidated Joint Ventures (Summary Of Company's Investment In Unconsolidated Joint Ventures) (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013		Dec. 23, 2013	21-May-14
In Thousands, unless otherwise specified
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	$247,468		$181,129
Accounts payable, accrued expenses and other liabilities	126,971		121,286
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	15,779		15,797
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	2,161	[1]	3,201	[1]
Rosewood Lafayette Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	62	[1]	857	[1]
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	6,029	[2],[3]	6,455	[2],[3]
Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	2,524	[4]
PruRose Riverwalk G, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	955		3,117
Elmajo Urban Renewal Associates, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures			203
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	27,051	[5]	26,838	[5]
Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,747		3,207
PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,087		2,206
Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,800	[1],[6]	2,068	[1],[6]
RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	11,282		7,567
Estuary Urban Renewal Unit B, LLC [Member
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures			24
Riverpark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	4,744		3,655
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	49,327		46,628		46,500
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	34,954	[7]				30,600
RoseGarden Monaco, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,283		1,224
Grand Jersey Waterfront Urban Renewal Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	337		337
Red Bank Corporate Plaza, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	3,963		4,046
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	5,620		5,514
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,993		1,753
Hillsborough 206 Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,962		1,962
KPG-P 100 IMW JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures			1,887
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	6,140
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	59,911	[8]
Plaza VIII & IX Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	4,022		3,702
Roseland/North Retail, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	1,828	[1]	1,930	[1]
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Accounts payable, accrued expenses and other liabilities	1,854		1,706
Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures			36,258	[9]
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	$907	[10]	$693	[10]
[1]	The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the Company is not expected to meaningfully participate in the venture's cash flows in the near term.
[2]	Through the joint venture, the Company also owns a 12.5 percent interest in a 50,973 square feet retail building ("Shops at 40 Park") and a 25 percent interest in a to-be-built 59-unit, five story multi-family rental development property ("Lofts at 40 Park").
[3]	The Company's ownership interests in this venture are subordinate to its partner's preferred capital balance and the payment of the outstanding balance remaining on a note ($975 as of December 31, 2014), and is not expected to meaningfully participate in the venture's cash flows in the near term.
[4]	On August 15, 2014, the Company acquired the equity interests of its joint venture partner in Overlook Ridge JV 2C/3B, L.L.C. for $2.97 million and LR Overlook Phase II, L.L.C., the property-owning entity owned by Overlook Ridge JV, L.L.C., which increased its ownership to 50 percent in two operating multi-family properties. The Company also acquired the equity interests of its joint venture partner in LR Overlook Phase III, L.L.C. and Overlook Ridge, L.L.C. for $0.6 million and $12.99 million respectively, which increased its ownership to 100 percent in developable land (See Note 3: Real Estate Transactions - Acquisitions).
[5]	The Company also owns a 50 percent interest in a vacant land parcel to accommodate the development of approximately 295 additional units of which 252 are currently approved.
[6]	The Company also owns a 20 percent residual interest in undeveloped land parcels: parcels 6, I, and J ("Port Imperial North Land") that can accommodate the development of 836 apartment units.
[7]	See discussion Unconsolidated Joint Venture Transactions following in this footnote.
[8]	Includes undivided interests in the same manner as investments in noncontrolling partnership, pursuant to ASC 970-323-25-12. See discussion in Unconsolidated Joint Venture Transactions following in this footnote.
[9]	The joint venture collected net proceeds of $47.2 million at maturity, of which the Company received its share of $37.8 million on August 6, 2014.
[10]	The Company owns other interests in various unconsolidated joint ventures, including interests in assets previously owned and interest in ventures whose businesses are related to its core operations. These ventures are not expected to significantly impact the Company's operations in the near term.

Investments_In_Unconsolidated_7

Investments In Unconsolidated Joint Ventures (Summary Of Results Of Operations Of Unconsolidated Joint Ventures) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Investments In Unconsolidated Joint Ventures [Abstract]
Total revenues	$305,034	$255,510	$68,183
Operating and other expenses	-233,320	-217,739	-37,008
Depreciation and amortization	-42,985	-32,889	-10,139
Interest expense	-32,862	-16,709	-6,775
Net income (loss)	($4,133)	($11,827)	$14,261

Investments_In_Unconsolidated_8

Investments In Unconsolidated Joint Ventures (Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures	($363)	($1,268)	$443	($1,235)	($268)	($229)	($80)	($1,750)	($2,423)	($2,327)	$4,089
Marbella RoseGarden, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-19	-540	13
RoseGarden Monaco Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-1,040	-1,560	-311
Rosewood Lafayette Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-853	-1,131	-197
PruRose Port Imperial South 15, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures										-606	-533
Rosewood Morristown, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-345	-509	-25
Overlook Ridge JV 2C/3B, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-384	293	-11
PruRose Riverwalk G, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-2,139	-985	-142
Elmajo Urban Renewal Associates, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-203	-345	-83
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-139	-2,639
Portside Master Company, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-1,163	-421	-5
PruRose Port Imperial South 13, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-863	-664	-87
Roseland/Port Imperial Partners, L.P. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-646	-740
RoseGarden Marbella South, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures										-57	-13
Estuary Urban Renewal Unit B, LLC [Member
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-15	-157
Riverpark At Harrison I, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-150
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-75
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-218
Grand Jersey Waterfront Urban Renewal Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-54	-77
Red Bank Corporate Plaza, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									380	372	360
12 Vreeland Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									106	74	427
BNES Associates III [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									240	-14	-323
Hillsborough 206 Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-10	-35
KPG-P 100 IMW JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-1,887	-913
Keystone-TriState [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-318
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									624
Plaza VIII & IX Associates, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									320	99	30
Roseland/North Retail, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									-102	-230	-80
South Pier At Harborside [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									2,602	2,519	2,368
Stamford SM LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									2,337	3,719	3,078
Other [Member]
Schedule of Equity Method Investments [Line Items]
Company's equity in earnings (loss) of unconsolidated joint ventures									$1,591	$2,220	($377)

Investments_In_Unconsolidated_9

Investments In Unconsolidated Joint Ventures (Harborside Unit A Urban Renewal, L.L.C.) (Narrative) (Details) (USD $)	12 Months Ended		0 Months Ended
	Dec. 31, 2014		Aug. 01, 2014	Dec. 31, 2013	21-May-14
	item
Schedule of Equity Method Investments [Line Items]
Interest rate
Company's investment in unconsolidated joint ventures	$247,468,000			$181,129,000
Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	763	[1]
Interest rate	5.20%	[1],[2]
Percentage of interest in venture	85.00%
Company's investment in unconsolidated joint ventures	34,954,000	[1]			30,600,000
Capital credit receivable per developable square foot	30
Aggregate capital credits	20,600,000
Holding and distribution pattern under operating agreement	In general, the operating agreement of URL-Harborside provides that net operating cash flows are distributed first, to the members in respect of preferred return, as defined, until each member shall have received payment of the accrued and unpaid preferred return; and, thereafter, 75 percent to the Company and 25 percent to ISA.
Harborside Unit A Urban Renewal, LLC [Member] | Construction Loan [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity			192,000,000
Outstanding borrowings under the facility	0
Interest rate			5.20%
Loan maturity date			1-Aug-29
Harborside Unit A Urban Renewal, LLC [Member] | Ironstate Harborside-A, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Company's investment in unconsolidated joint ventures	5,400,000
Percentage of capital event cash flows distributed after initial internal rate of return reached	35.00%
Percentage of capital event cash flows distributed	25.00%
Percentage of operating return on capital	25.00%
Harborside Residential Project [Member] | Harborside Unit A Urban Renewal, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	763
Total project costs	320,000,000
Development costs	65,100,000
State tax credit	$33,000,000
[1]	See discussion Unconsolidated Joint Venture Transactions following in this footnote.
[2]	The construction/permanent loan has a maximum borrowing amount of $192,000.

Recovered_Sheet1

Investments In Unconsolidated Joint Ventures (KPG-MCG Curtis JV, LLC / Curtis Center) (Narrative) (Details) (USD $)	12 Months Ended				0 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Oct. 01, 2014	Jun. 06, 2014	Sep. 02, 2014
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture		[1],[2],[3]
Investments in unconsolidated joint ventures	$247,468,000		$181,129,000
Interest rate
Repayment of loans payable	83,808,000		20,715,000	52,318,000
Curtis Center Property [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated joint ventures	125,000,000
Curtis Center Property [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%
Investments in unconsolidated joint ventures	62,500,000
Curtis Center Property [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%
Investments in unconsolidated joint ventures	62,500,000
KPG-MCG Curtis JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%	[1],[4]
Investments in unconsolidated joint ventures	59,911,000	[4]
Area of property (in square feet)	885,000	[4]
Threshold of member unreturned capital for distribution of net operating cash flows	0
KPG-MCG Curtis JV, LLC [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%
KPG-MCG Curtis JV, LLC [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%
KPG-MCG Curtis JV, LLC [Member] | Curtis Center Property [Member]
Schedule of Equity Method Investments [Line Items]
Lease period	29 years
90-Day Loan 1 [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Maturity period						90 days
Loan to affiliate						52,300,000
Interest rate						3.50%
Repayment of loans payable					52,300,000
90-Day Loan 2 [Member] | Keystone Property Group [Member]
Schedule of Equity Method Investments [Line Items]
Maturity period						90 days
Loan to affiliate						10,000,000
Interest rate						3.50%
Repayment of loans payable							$10,000,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).
[4]	Includes undivided interests in the same manner as investments in noncontrolling partnership, pursuant to ASC 970-323-25-12. See discussion in Unconsolidated Joint Venture Transactions following in this footnote.

Recovered_Sheet2

Investments In Unconsolidated Joint Ventures (150 Main Street, L.L.C.) (Narrative) (Details) (USD $)	0 Months Ended		12 Months Ended
	Aug. 22, 2013	Oct. 23, 2012	Dec. 31, 2014		Aug. 22, 2013	Oct. 23, 2012
						item
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture				[1],[2],[3]
Eastchester Project [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	76.25%	26.25%			76.25%	26.25%
Number of units		108				108
Business acquisition, cash paid	$4,900,000	$2,100,000
Percentage return on unrecovered capital			8.00%
Total project costs			50,000,000
Project costs incurred			13,900,000
Holding period gain (loss)	0
Amount of project costs funded by members			21,200,000
Eastchester Project [Member] | 150 Main Street, L.L.C. [Member] | Construction Loan [Member]
Schedule of Equity Method Investments [Line Items]
Maximum borrowing capacity			28,800,000
Eastchester Project [Member] | JMP Eastchester, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Third party ownership percentage		26.25%				26.25%
Eastchester Project [Member] | Hudson Valley Land Holdings, L.L.C. [Member]
Schedule of Equity Method Investments [Line Items]
Third party ownership percentage	23.75%	47.50%			23.75%	47.50%
Percentage return on unrecovered capital			8.00%
Eastchester Project [Member] | Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Amount of project costs funded by members			$20,900,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).

Recovered_Sheet3

Investments In Unconsolidated Joint Ventures (Crystal House Apartments Investors LLC) (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	Mar. 20, 2013	Dec. 31, 2014		Mar. 20, 2013
		item		item
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture			[1],[2],[3]
Number of units available for development	295			295
Number of approved units available for development	252			252
Mortgage loans, carrying amount		$1,673,364,000
Interest rate of senior unsecured notes
Parent Company [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of capital event cash flows distributed		50.00%
UBS Global Asset Management [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of capital event cash flows distributed		50.00%
Crystal House Apartments Investors LLC [Member]
Schedule of Equity Method Investments [Line Items]
Number of units	828	828	[4]	828
Venture property acquisition cost	262,500,000			262,500,000
Percentage of interest in venture	25.00%	25.00%	[1],[4]	25.00%
Percentage of interest in developable land	50.00%	50.00%		50.00%
Business acquisition, cash paid	30,200,000
Number of units available for development		295
Number of approved units available for development		252
Mortgage loans, carrying amount		$165,000,000	[4]
Interest rate of senior unsecured notes		3.17%	[4]
Mortgage loan, maturity date		1-Apr-20	[4]
Initial term of interest only payments		5 years
Mortgage loan, maturity period		30 years
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).
[4]	The Company also owns a 50 percent interest in a vacant land parcel to accommodate the development of approximately 295 additional units of which 252 are currently approved.

Recovered_Sheet4

Investments In Unconsolidated Joint Ventures (KPG-P 100 IMW JV, LLC) (Details) (USD $)	12 Months Ended		0 Months Ended
	Dec. 31, 2014		Dec. 09, 2013	Dec. 31, 2013
	item			item
	sqft
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture		[1],[2],[3]
Number of parking spaces				850
Mortgage loans, carrying amount	$1,673,364,000
Interest rate
KPG-P [Member]
Schedule of Equity Method Investments [Line Items]
Threshold of member unreturned capital for distribution of net operating cash flows	0
Threshold of member unreturned capital for distribution of capital event flows	0
KPG-IMW Owner, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Mortgage loans, carrying amount	61,500,000
Interest rate	7.00%
KPG-MCG's Interest In KPG-P [Member]
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				57.70%
KPG's Interest In KPG-P [Member]
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				17.89%
Parkway's Interest In KPG-P [Member]
Schedule of Equity Method Investments [Line Items]
Investment ownership percentage				24.40%
KPG-P 100 IMW JV, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	33.33%	[1]		57.77%
Number of stories	9
Area of property (in square feet)	339,615
Business acquisition, cash paid	40,500,000
Total project costs	20,000,000
Number of parking spaces	110
Mortgage loans, carrying amount	61,500,000
Mortgage loan, maturity date	9-Sep-16
Number of extension options	2
Credit facility, extension period	1 year
Construction reserve	25,000,000
Construction reserve, amount outstanding	15,800,000
KPG-P 100 IMW JV, LLC [Member] | KPG-IMW Owner, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Business acquisition, cash paid			$2,800,000
KPG-P 100 IMW JV, LLC [Member] | Parkway's Interest In KPG-P [Member]
Schedule of Equity Method Investments [Line Items]
Area of property (in square feet)	55,000
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).

Recovered_Sheet5

Investments In Unconsolidated Joint Ventures (Capitol Place Mezz LLC) (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 23, 2013
			item
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture		[1],[2],[3]
Number of parking spaces			850
Investments in unconsolidated joint ventures	$247,468,000		$181,129,000
Interest rate
Capitol Place Mezz LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage of interest in venture	50.00%	[1]		50.00%
Number of units	377
Investments in unconsolidated joint ventures	49,327,000		46,628,000	46,500,000
Interest rate	4.82%	[4]
Capitol Place Mezz LLC [Member] | FB Capitol Place LLC [Member]
Schedule of Equity Method Investments [Line Items]
Threshold of member unreturned capital for distribution of capital event flows	2,500,000
WDC Project [Member]
Schedule of Equity Method Investments [Line Items]
Number of units				377
Area of property (in square feet)				25,000
Number of parking spaces				309
Total project costs	194,400,000
Costs of the project incurred	171,500,000
WDC Project [Member] | Construction Loan [Member]
Schedule of Equity Method Investments [Line Items]
Mortgage loan, maturity period	20 years
Maximum borrowing capacity	100,700,000
Outstanding borrowings under the facility	$74,000,000
Interest rate	4.82%
Loan maturity date	1-Jul-33
Amortization period	30 years
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).
[4]	The construction/permanent loan has a maximum borrowing amount of $100,700 with amortization starting in August 2017.

Deferred_Charges_Goodwill_And_2

Deferred Charges, Goodwill And Other Assets, Net (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred leasing costs	$239,138,000		$258,648,000
Deferred financing costs	24,042,000		25,366,000
Deferred charges, gross	263,180,000		284,014,000
Accumulated amortization	-122,358,000		-131,669,000
Deferred charges, net	140,822,000		152,345,000
Notes receivable	21,491,000	[1]	21,986,000	[1]
In-place lease values, related intangible and other assets, net	6,565,000		13,659,000
Goodwill	2,945,000		2,945,000
Prepaid expenses and other assets, net	32,827,000		27,584,000
Total deferred charges, goodwill and other assets	204,650,000		218,519,000
Lease revenue	516,727,000		540,165,000		535,822,000
Mortgage Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	10,400,000
Spread over LIBOR	6.00%
8% Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	7,800,000
Interest rate	8.00%
Interest-Free Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable	3,300,000
Acquired In-Place Above And Below Market Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Lease revenue	$700,000		$1,500,000		$1,400,000
[1]	Includes as of December 31, 2014: a mortgage receivable for $10.4 million which bears interest at LIBOR plus six percent and matures in August 2015; a note receivable for $7.8 million which bears interest at eight percent and matures in October 2017; and an interest-free note receivable with a net present value of $3.3 million and matures in April 2023. The Company believes these balances are fully collectable.

Deferred_Charges_Goodwill_And_3

Deferred Charges, Goodwill And Other Assets, Net (Summary Of Scheduled Amortization) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Acquired Above Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2015	($338,000)
2016	-288,000
2017	-261,000
2018	-233,000
2019	-209,000
Below Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2015	564,000
2016	370,000
2017	364,000
2018	310,000
2019	156,000
Acquired Above And Below Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2015	226,000
2016	82,000
2017	103,000
2018	77,000
2019	-53,000
Acquired In-Place Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2015	1,231,000
2016	1,224,000
2017	918,000
Amortization expense	$6,900,000	$10,700,000	$10,200,000

Deferred_Charges_Goodwill_And_4

Deferred Charges, Goodwill And Other Assets, Net (Summary Of Notional Fair Value Of Derivative Financial Instruments) (Details) (USD $)

3 Months Ended

12 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Derivatives, Fair Value [Line Items]

Fair Value

$95,000

$95,000

Interest and other investment income (loss)

1,399,000

908,000

922,000

386,000

1,616,000

187,000

1,094,000

6,000

3,615,000

2,903,000

34,000

Gain (Loss) on Derivative Instruments [Member]

Derivatives, Fair Value [Line Items]

Interest and other investment income (loss)

-79,000

LIBOR Cap One [Member]

Derivatives, Fair Value [Line Items]

Notional Value

51,000,000

[1]

51,000,000

[1]

Strike Rate

1.50%

1.50%

Effective Date

1-Sep-14

Expiration Date

1-Oct-15

Fair Value

1,000

1,000

LIBOR Cap Two [Member]

Derivatives, Fair Value [Line Items]

Notional Value

24,000,000

[1]

24,000,000

[1]

Strike Rate

1.50%

1.50%

Effective Date

1-Sep-14

Expiration Date

1-Oct-15

Fair Value

1,000

1,000

LIBOR Cap Three [Member]

Derivatives, Fair Value [Line Items]

Notional Value

51,000,000

[1]

51,000,000

[1]

Strike Rate

1.75%

1.75%

Effective Date

1-Oct-15

Expiration Date

1-Oct-16

Fair Value

64,000

64,000

LIBOR Cap Four [Member]

Derivatives, Fair Value [Line Items]

Notional Value

24,000,000

[1]

24,000,000

[1]

Strike Rate

1.75%

1.75%

Effective Date

1-Oct-15

Expiration Date

1-Oct-16

Fair Value

$29,000

$29,000

[1]

The notional value is an indication of the extent of our involvement in these instruments at that time, but does not represent exposure to credit, interest rate or market risks.

Restricted_Cash_Details

Restricted Cash (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Restricted Cash [Abstract]
Security deposits	$7,795	$8,534
Escrow and other reserve funds	26,450	11,260
Total restricted cash	$34,245	$19,794

Discontinued_Operations_Narrat

Discontinued Operations (Narrative) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	sqft	item
	item	sqft
	property	property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties sold	16	24
Area of property sold (in square feet)	2,610,931	3,006,409
Number of land parcels sold		3
Sales proceeds	$319,239	$390,615	[1]
[1]	This amount excludes approximately $535,000 of net closing prorations and related adjustments received from sellers at closing.

Discontinued_Operations_Summar

Discontinued Operations (Summary Of Income From Discontinued Operations And Related Realized And Unrealized Gains (Losses)) (Details) (USD $)	3 Months Ended					12 Months Ended					3 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012		Mar. 31, 2012	Dec. 31, 2012
						sqft	sqft				sqft
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues							$33,601,000		$66,882,000
Operating and other expenses							-13,454,000		-26,484,000
Depreciation and amortization							-8,218,000		-17,765,000
Interest expense							-118,000		-755,000
Income from discontinued operations	-9,000		2,157,000	4,530,000	5,133,000		11,811,000		21,878,000
Loss from early extinguishment of debt				-703,000			-703,000
Impairments							-23,851,000	[1]	-8,400,000	[1]
Unrealized losses on disposition of rental property									-9,213,000	[2]
Realized gains on disposition of rental property							83,371,000		4,438,000
Realized gains (losses) and unrealized losses on disposition of rental property and impairments, net	-1,559,000	[3]	47,321,000	13,758,000			59,520,000		-13,175,000
Total discontinued operations, net	-1,568,000		49,478,000	17,585,000	5,133,000		70,628,000		8,703,000
Area of property sold (in square feet)						2,610,931	3,006,409
Valuation allowance						14,400,000
Sales proceeds						319,239,000	390,615,000	[4]
Gain (loss) on sale of property						54,848,000	83,371,000	[5]
Rental property held for sale, net	307,244,000					264,391,000	307,244,000
Accumulated depreciation	1,400,988,000					1,414,305,000	1,400,988,000
95 Chestnut Ridge Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of property sold (in square feet)											47,700
Valuation allowance											500,000
Sales proceeds											4,000,000
Gain (loss) on sale of property											0
Moorestown, New Jersey [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of property sold (in square feet)											222,258
Valuation allowance											1,600,000
Sales proceeds												19,400,000
Gain (loss) on sale of property												-100,000
Number of properties held for sale											3
19 Skyline Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of property sold (in square feet)							248,400	[6]	248,400
Valuation allowance									7,100,000			7,100,000
Sales proceeds							16,131,000	[6]
Gain (loss) on sale of property							126,000	[6]
Rental property held for sale, net	16,005,000	[6]					16,005,000	[6]
55 Corporate Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of property sold (in square feet)							204,057		204,057
Sales proceeds							70,967,000
Gain (loss) on sale of property							19,659,000
Rental property held for sale, net	51,308,000						51,308,000
19 Skyline Drive And 55 Corporate Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of properties held for sale									2			2
Rental property held for sale, net									60,900,000			60,900,000
Accumulated depreciation									$16,800,000			$16,800,000
[1]	Represents impairment charges recorded on certain properties prior to their sale.
[2]	Represents valuation allowances on properties identified as held for sale in 2012, as follows:At March 31, 2012, the Company identified as held for sale its 47,700 square foot office building located at 95 Chestnut Ridge Road in Montvale, New Jersey. The Company determined that the carrying amount of this property was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $0.5 million at March 31, 2012. On July 25, 2012, the Company sold the building for approximately $4.0 million (with no gain from the sale).At March 31, 2012, the Company identified as held for sale three office buildings totaling 222,258 square feet in Moorestown, New Jersey. The Company determined that the aggregate carrying amount of these properties was not expected to be recovered from estimated net sales proceeds and, accordingly, recognized a valuation allowance of $1.6 million at June 30, 2012. On November 7, 2012, the Company sold the buildings for approximately $19.4 million and recognized a loss of approximately $0.1 million from the sale.At December 31, 2012, the Company identified as held for sale its 248,400 square foot office building located at 19 Skyline Drive in Hawthorne, New York. The Company determined that the carrying amount of this property was not expected to be recovered from estimated sales proceeds and accordingly recognized a valuation allowance of $7.1 million at December 31, 2012. Also at December 31, 2012, the Company identified as held for sale its 204,057 square foot office building located at 55 Corporate Drive in Bridgewater, New Jersey. The two properties held for sale at December 31, 2012 carried an aggregate book value of $60.9 million, net of accumulated depreciation of $16.8 million and a valuation allowance of $7.1 million. As of April 10, 2013, the Company sold 19 Skyline Drive for approximately $16.1 million and recognized a gain of approximately $0.1 million. As of April 26, 2013, the Company sold 55 Corporate Drive for approximately $71 million and recognized a gain of approximately $19.7 million.
[3]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[4]	This amount excludes approximately $535,000 of net closing prorations and related adjustments received from sellers at closing.
[5]	This amount, net of impairment charges recorded in 2013 of $23,851,000 on certain of the properties prior to their sale (per Note [d] above), comprises the $59,520,000 of realized gains (losses) and unrealized losses on disposition of rental property and impairments, net, for the year ended December 31, 2013.B See Note 7: Discontinued Operations.
[6]	The Company recognized a valuation allowance of $7.1 million on this property identified as held for sale at December 31, 2012. In connection with the sale, the Company provided an interest-free note receivable to the buyer of $5 million (with a net present value of $3.7 million at closing) which matures in 2023 and requires monthly payments of principal. See Note 5: Deferred charges, goodwill and other assets.

Senior_Unsecured_Notes_Details

Senior Unsecured Notes (Details) (USD $)	3 Months Ended				12 Months Ended					0 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Dec. 17, 2014
Debt Instrument [Line Items]
Senior Unsecured Notes	$1,267,744		$1,616,575		$1,267,744		$1,616,575
Interest rate of senior unsecured notes
Repayments of senior unsecured notes					350,000		100,000		221,019
Loss from early extinguishment of debt	-582		-156		-582		-156		-4,960
5.125% Senior Unsecured Notes, Due February 15, 2014 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes			200,030	[1]			200,030	[1]
Effective Rate	5.11%	[1],[2]			5.11%	[1],[2]
Interest rate of senior unsecured notes	5.13%				5.13%
Maturity date of the Senior Unsecured Notes					15-Feb-14
5.125% Senior Unsecured Notes, Due January 15, 2015 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes			149,902	[3]			149,902	[3]
Effective Rate	5.30%	[2],[3]			5.30%	[2],[3]
Interest rate of senior unsecured notes	5.13%				5.13%
Maturity date of the Senior Unsecured Notes					15-Jan-15
Redemption premium										100.38%
Repayments of senior unsecured notes										153,800
Loss from early extinguishment of debt										600
5.800% Senior Unsecured Notes, Due January 15, 2016 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes	200,086		200,161		200,086		200,161
Effective Rate	5.81%	[2]			5.81%	[2]
Interest rate of senior unsecured notes	5.80%				5.80%
Maturity date of the Senior Unsecured Notes					15-Jan-16
2.500% Senior Unsecured Notes, Due December 15, 2017 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes	249,150		248,855		249,150		248,855
Effective Rate	2.80%	[2]			2.80%	[2]
Interest rate of senior unsecured notes	2.50%				2.50%
Maturity date of the Senior Unsecured Notes					15-Dec-17
7.750% Senior Unsecured Notes, Due August 15, 2019 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes	249,013		248,799		249,013		248,799
Effective Rate	8.02%	[2]			8.02%	[2]
Interest rate of senior unsecured notes	7.75%				7.75%
Maturity date of the Senior Unsecured Notes					15-Aug-19
4.500% Senior Unsecured Notes Due April 18, 2022 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes	299,565		299,505		299,565		299,505
Effective Rate	4.61%	[2]			4.61%	[2]
Interest rate of senior unsecured notes	4.50%				4.50%
Maturity date of the Senior Unsecured Notes					18-Apr-22
3.150% Senior Unsecured Note, Due May 15, 2023 [Member]
Debt Instrument [Line Items]
Senior Unsecured Notes	$269,930		$269,323		$269,930		$269,323
Effective Rate	3.52%	[2]			3.52%	[2]
Interest rate of senior unsecured notes	3.15%				3.15%
Maturity date of the Senior Unsecured Notes					15-May-23
[1]	On February 17, 2014, the Company repaid these notes at their maturity using available cash and borrowings on the Companybs unsecured revolving credit facility.
[2]	Includes the cost of terminated treasury lock agreements (if any), offering and other transaction costs and the discount/premium on the notes, as applicable.
[3]	These notes were redeemed on December 17, 2014. The redemption price, including a make-whole premium, was 100.380 percent of the principal amount of the Notes, plus all accrued and unpaid interest up to the Redemption Date. The Company funded the redemption price, including accrued and unpaid interest, of approximately $153.8 million using available cash and borrowings on the Companybs unsecured revolving credit facility. In connection with the redemption, the Company recorded approximately $0.6 million as a loss from early extinguishment of debt (including the write-off of unamortized deferred financing costs).

Unsecured_Revolving_Credit_Fac2

Unsecured Revolving Credit Facility (Narrative) (Details) (USD $)	12 Months Ended	0 Months Ended
	Dec. 31, 2014	Jul. 15, 2013
	item
Unsecured Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Number of lending institutions	17
Borrowing capacity under the credit facility	$600,000,000
Expandable borrowing capacity under the credit facility	1,000,000,000
Credit facility maturity date	1-Jul-17
Number of extension options	2
Credit facility, extension period	6 months
Line of credit facility, bid feature, current borrowing capacity	300,000,000
Terms of the unsecured facility	The terms of the unsecured facility include certain restrictions and covenants which limit, among other things the incurrence of additional indebtedness, the incurrence of liens and the disposition of real estate properties (to the extent that: (i) such property dispositions cause the Company to default on any of the financial ratios of the facility described below, or (ii) the property dispositions are completed while the Company is under an event of default under the facility, unless, under certain circumstances, such disposition is being carried out to cure such default), and which require compliance with financial ratios relating to the maximum leverage ratio (60 percent), the maximum amount of secured indebtedness (40 percent), the minimum amount of fixed charge coverage (1.5 times), the maximum amount of unsecured indebtedness (60 percent), the minimum amount of unencumbered property interest coverage (2.0 times) and certain investment limitations (generally 15 percent of total capitalization).
Terms of dividend restriction	If an event of default has occurred and is continuing, the Corporation will not make any excess distributions except to enable the Corporation to continue to qualify as a REIT under the Code.
Unsecured Revolving Credit Facility 1 [Member]
Line Of Credit Facility [Line Items]
Credit facility extension fee, basis points	0.08%
Unsecured Revolving Credit Facility 2 [Member]
Line Of Credit Facility [Line Items]
Credit facility extension fee, basis points	0.08%
Previous Unsecured Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Borrowing capacity under the credit facility		$600,000,000
Credit facility extension fee, basis points		0.25%
Spread over LIBOR		1.25%
Minimum [Member] | Unsecured Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Fixed charge coverage ratio	1.5
Unencumbered property interest coverage	2
Maximum [Member] | Unsecured Revolving Credit Facility [Member]
Line Of Credit Facility [Line Items]
Leverage ratio	60.00%
Secured indebtedness	40.00%
Unsecured indebtedness	60.00%
Investment limitations as a percentage of total capitalization	15.00%

Unsecured_Revolving_Credit_Fac3

Unsecured Revolving Credit Facility (Change In The Operating Partnership's Unsecured Debt Ratings) (Details) (Unsecured Revolving Credit Facility [Member])	12 Months Ended
	Dec. 31, 2014
No Ratings Or Less Than Baa3 [Member] | No Ratings Or Less Than BBB- [Member]
Line Of Credit Facility [Line Items]
Unsecured Debt Ratings	No ratings or less than BBB-/Baa3
Interest Rate - Applicable Basis Points Above LIBOR	1.70%
Facility Fee Basis Points	0.35%
Moody's, Baa3 Rating [Member] | Standard & Poor's, BBB- Rating [Member]
Line Of Credit Facility [Line Items]
Unsecured Debt Ratings	BBB- or Baa3 (current)
Interest Rate - Applicable Basis Points Above LIBOR	1.30%
Facility Fee Basis Points	0.30%
Moody's, Baa2 Rating [Member] | Standard & Poor's, BBB Rating [Member]
Line Of Credit Facility [Line Items]
Unsecured Debt Ratings	BBB or Baa2
Interest Rate - Applicable Basis Points Above LIBOR	1.10%
Facility Fee Basis Points	0.20%
Moody's, Baa1 Rating [Member] | Standard & Poor's, BBB+ Rating [Member]
Line Of Credit Facility [Line Items]
Unsecured Debt Ratings	BBB+ or Baa1
Interest Rate - Applicable Basis Points Above LIBOR	1.00%
Facility Fee Basis Points	0.15%
A3 Or Higher [Member] | A- Or Higher [Member]
Line Of Credit Facility [Line Items]
Unsecured Debt Ratings	A- or A3 or higher
Interest Rate - Applicable Basis Points Above LIBOR	0.93%
Facility Fee Basis Points	0.13%

Mortgages_Loans_Payable_And_Ot2

Mortgages, Loans Payable And Other Obligations (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
	property
Debt Instrument [Line Items]
Number of properties with encumbered company mortgages	30
Book value of encumbered properties	$998,000,000
Cash paid for interest	119,664,000	123,213,000	120,089,000
Interest capitalized	15,470,000	12,885,000	4,342,000
Total indebtedness	2,088,654,000	2,362,766,000
Total indebtedness, weighted average interest rate	5.64%	5.62%
Unconsolidated Joint Venture [Member]
Debt Instrument [Line Items]
Interest capitalized	4,646,000	1,326,000	235,000
Revolving Credit Facility Borrowings And Other Variable Rate Mortgage Debt [Member]
Debt Instrument [Line Items]
Total indebtedness	159,860,000	80,228,000
Total indebtedness, weighted average interest rate	3.83%	2.74%
Fixed Rate Debt And Other Obligations [Member]
Debt Instrument [Line Items]
Total indebtedness	$1,928,794,000	$2,282,538,000
Total indebtedness, weighted average interest rate	5.79%	5.72%

Mortgages_Loans_Payable_And_Ot3

Mortgages, Loans Payable And Other Obligations (Summary Of Mortgages, Loans Payable And Other Obligations) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2014		Aug. 15, 2014
Debt Instrument [Line Items]
Mortgages, loans payable and other obligations	$746,191,000		$820,910,000
Loss from early extinguishment of debt	703,000
Percentage of interest in venture				[1],[2],[3]
6301 Ivy Lane [Member]
Debt Instrument [Line Items]
Property Name			6301 Ivy Lane (b)	[4]
Lender			RGA Reinsurance Company	[4]
Effective Rate			5.52%	[4],[5]
Mortgages, loans payable and other obligations	5,447,000	[4]		[4]
395 West Passaic [Member]
Debt Instrument [Line Items]
Property Name			395 West Passaic (c)	[6]
Lender			State Farm Life Insurance Co.	[6]
Effective Rate			6.00%	[5],[6]
Mortgages, loans payable and other obligations	9,719,000	[6]		[6]
35 Waterview Boulevard [Member]
Debt Instrument [Line Items]
Property Name			35 Waterview Boulevard (d)	[7]
Lender			Wells Fargo CMBS	[7]
Effective Rate			6.35%	[5],[7]
Mortgages, loans payable and other obligations	18,417,000	[7]		[7]
233 Canoe Brook Road [Member]
Debt Instrument [Line Items]
Property Name			233 Canoe Brook Road (e)	[8]
Lender			The Provident Bank	[8]
Effective Rate			4.38%	[5],[8]
Mortgages, loans payable and other obligations	3,877,000	[8]		[8]
Port Imperial South 4/5 [Member]
Debt Instrument [Line Items]
Property Name			Port Imperial South 4/5 (f)	[9]
Lender			Wells Fargo Bank N.A.	[9]
Effective Rate			3.50%	[5],[9]
Spread over LIBOR			3.50%
Mortgages, loans payable and other obligations	36,950,000	[9]		[9]
6 Becker, 85 Livingston, 75 Livingston And 20 Waterview [Member]
Debt Instrument [Line Items]
Property Name			6 Becker, 85 Livingston, 75 Livingston & 20 Waterview
Lender			Wells Fargo CMBS
Effective Rate			10.26%	[5]
Mortgages, loans payable and other obligations	64,233,000		65,035,000
Loan maturity date			11-Aug-14	[10]
Number of properties used to collateralize mortgage			4
4 Sylvan [Member]
Debt Instrument [Line Items]
Property Name			4 Sylvan
Lender			Wells Fargo CMBS
Effective Rate			10.26%	[5]
Mortgages, loans payable and other obligations	14,538,000		14,575,000
Loan maturity date			11-Aug-14	[10]
10 Independence Boulevard [Member]
Debt Instrument [Line Items]
Property Name			10 Independence
Lender			Wells Fargo CMBS
Effective Rate			10.26%	[5]
Mortgages, loans payable and other obligations	16,638,000		16,924,000
Loan maturity date			11-Aug-14	[10]
Overlook - Site IIID, IIIC, IIIA [Member]
Debt Instrument [Line Items]
Property Name			Overlook - Site IIID,IIIC, IIIA (i)	[11]
Lender			Wells Fargo Bank N.A.	[11]
LIBOR			LIBOR+3.50	[11],[5]
Spread over LIBOR			3.50%
Mortgages, loans payable and other obligations			17,260,000	[11]
Loan maturity date			2-Mar-15	[11]
Overlook - Site IIIB [Member]
Debt Instrument [Line Items]
Property Name			Overlook - Site IIB (Quarrystone I) (i)	[11]
Lender			Wells Fargo Bank N.A.	[11]
LIBOR			LIBOR+2.50	[11],[5]
Spread over LIBOR			2.50%
Mortgages, loans payable and other obligations			5,787,000	[11]
Loan maturity date			14-Apr-15	[11]
9200 Edmonston Road [Member]
Debt Instrument [Line Items]
Property Name			9200 Edmonston Road (j)	[12]
Lender			Principal Commercial Funding L.L.C.	[12]
Effective Rate			5.53%	[12],[5]
Mortgages, loans payable and other obligations	4,115,000	[12]	3,951,000	[12]
Loan maturity date			1-May-15	[12]
Port Imperial South [Member]
Debt Instrument [Line Items]
Property Name			Port Imperial South
Lender			Wells Fargo Bank N.A.
LIBOR			LIBOR+1.75	[5]
Spread over LIBOR			1.75%
Mortgages, loans payable and other obligations	43,278,000		44,119,000
Loan maturity date			19-Sep-15
4 Becker [Member]
Debt Instrument [Line Items]
Property Name			4 Becker
Lender			Wells Fargo CMBS
Effective Rate			9.55%	[5]
Mortgages, loans payable and other obligations	38,820,000		39,421,000
Loan maturity date			11-May-16
5 Becker [Member]
Debt Instrument [Line Items]
Property Name			5 Becker (k)	[13]
Lender			Wells Fargo CMBS	[13]
Effective Rate			12.83%	[13],[5]
Mortgages, loans payable and other obligations	13,092,000	[13]	13,867,000	[13]
Loan maturity date			11-May-16	[13]
210 Clay [Member]
Debt Instrument [Line Items]
Property Name			210 Clay (l)	[14]
Lender			Wells Fargo CMBS	[14]
Effective Rate			13.42%	[14],[5]
Mortgages, loans payable and other obligations	12,767,000	[14]	13,330,000	[14]
Loan maturity date			11-May-16	[14]
Curtis Center [Member]
Debt Instrument [Line Items]
Property Name			Curtis Center (m)	[15]
Lender			CCRE & PREFG	[15]
LIBOR			LIBOR+5.912	[15],[5]
Spread over LIBOR			4.55%
Mortgages, loans payable and other obligations			64,000,000	[15]
Loan maturity date			9-Oct-16	[15]
Percentage of interest in venture			50.00%
Number of extension options			3
Loan extension period			1 year
Deferred financing costs amortization interest rate			1.36%
Curtis Center [Member] | Senior Loan [Member]
Debt Instrument [Line Items]
Effective Rate			3.46%
Spread over LIBOR			3.29%
Mortgages, loans payable and other obligations			102,000,000
Percentage of interest in venture			50.00%
LIBOR measurement period			1 month
Curtis Center [Member] | Mezzanine Loan [Member]
Debt Instrument [Line Items]
Effective Rate			9.66%
Spread over LIBOR			9.50%
Mortgages, loans payable and other obligations			26,000,000
Percentage of interest in venture			50.00%
Maximum borrowing capacity			48,000,000
LIBOR measurement period			1 month
Various [Member]
Debt Instrument [Line Items]
Property Name			Various (n)	[16]
Lender			Prudential Insurance	[16]
Effective Rate			6.33%	[16],[5]
Mortgages, loans payable and other obligations	147,477,000	[16]	145,557,000	[16]
Loan maturity date			15-Jan-17	[16]
Number of properties used to collateralize mortgage			7
150 Main St. [Member]
Debt Instrument [Line Items]
Property Name			150 Main St.
Lender			Webster Bank
LIBOR			LIBOR+2.35	[5]
Spread over LIBOR			2.35%
Mortgages, loans payable and other obligations			1,193,000	[17]
Loan maturity date			30-Mar-17
Maximum borrowing capacity			28,800,000
23 Main Street [Member]
Debt Instrument [Line Items]
Property Name			23 Main Street
Lender			JPMorgan CMBS
Effective Rate			5.59%	[5]
Mortgages, loans payable and other obligations	29,843,000		29,210,000
Loan maturity date			1-Sep-18
Harborside Plaza 5 [Member]
Debt Instrument [Line Items]
Property Name			Harborside Plaza 5
Lender			The Northwestern Mutual Life Insurance Co. & New York Life Insurance Co.
Effective Rate			6.84%	[5]
Mortgages, loans payable and other obligations	225,139,000		221,563,000
Loan maturity date			1-Nov-18
100 Walnut Avenue [Member]
Debt Instrument [Line Items]
Property Name			100 Walnut Avenue
Lender			Guardian Life Insurance Co.
Effective Rate			7.31%	[5]
Mortgages, loans payable and other obligations	18,792,000		18,542,000
Loan maturity date			1-Feb-19
One River Center [Member]
Debt Instrument [Line Items]
Property Name			One River Center (o)	[18]
Lender			Guardian Life Insurance Co.	[18]
Effective Rate			7.31%	[18],[5]
Mortgages, loans payable and other obligations	43,049,000	[18]	42,476,000	[18]
Loan maturity date			1-Feb-19	[18]
Number of properties used to collateralize mortgage			3
Park Square [Member]
Debt Instrument [Line Items]
Property Name			Park Square
Lender			Wells Fargo Bank N.A.
LIBOR			LIBOR+1.872	[19],[5]
Spread over LIBOR			1.75%
Mortgages, loans payable and other obligations			27,500,000
Loan maturity date			10-Apr-19
Deferred financing costs amortization interest rate			0.12%
Port Imperial 4/5 Retail [Member]
Debt Instrument [Line Items]
Property Name			Port Imperial South 4/5 Retail
Lender			American General Life & A/G PC
Effective Rate			4.56%	[5]
Mortgages, loans payable and other obligations			4,000,000
Loan maturity date			1-Dec-21
Port Imperial 4/5 Garage Development [Member]
Debt Instrument [Line Items]
Property Name			Port Imperial South 4/5 Garage
Lender			American General Life & A/G PC
Effective Rate			4.85%	[5]
Mortgages, loans payable and other obligations			$32,600,000
Loan maturity date			1-Dec-29
Consolidated Land [Member] | Overlook Ridge Properties [Member]
Debt Instrument [Line Items]
Percentage of interest in developable land					100.00%
[1]	Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.
[2]	The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.
[3]	Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).
[4]	On April 1, 2014, the Company repaid the mortgage loan at par, using available cash.
[5]	Reflects effective rate of debt, including deferred financing costs, comprised of the cost of terminated treasury lock agreements (if any), debt initiation costs, mark-to-market adjustment of acquired debt and other transaction costs, as applicable.
[6]	On May 1, 2014, the Company repaid the mortgage loan at par, using available cash.
[7]	On May 12, 2014, the Company repaid the mortgage loan at par, using borrowings on the Companybs unsecured revolving credit facility.
[8]	On April 30, 2014, the Company repaid the mortgage loan at par, using available cash.
[9]	On November 3, 2014, the Company refinanced the mortgage loan with a different lender
[10]	The loan was not repaid at maturity and the Company has begun discussions with the lender regarding a potential deed-in-lieu of foreclosure in satisfaction of the obligation.
[11]	On August 15, 2014, the Company assumed these loans as a result of its acquisition of interests which increased its ownership to 100 percent in certain previously unconsolidated joint ventures which owned developable land.
[12]	The mortgage loan originally matured on May 1, 2013. The maturity date was extended until May 1, 2015 with the same interest rate. Excess cash flow, as defined, is being held by the lender for re-leasing costs. The deed for the property was placed in escrow and is available to the lender in the event of default or non-payment at maturity.
[13]	The cash flow from this property is insufficient to cover operating costs and debt service. Consequently, the Company notified the lender and suspended debt service payments in August 2013. The Company has begun discussions with the lender regarding a deed-in-lieu of foreclosure and began remitting available cash flow to the lender effective August 2013.
[14]	The cash flow from this property is insufficient to cover operating costs and debt service. Consequently, the Company notified the lender and suspended debt service payments in January 2015.
[15]	The Company owns a 50 percent tenants-in-common interest in the Curtis Center Property. The Companybs $64.0 million loan consists of its 50 percent interest in a $102 million senior loan with a current rate of 3.455 percent at December 31, 2014 and its 50 percent interest in a $26 million mezzanine loan (with a maximum borrowing capacity of $48 million) with a current rate of 9.661 percent at December 31, 2014. The senior loan rate is based on a floating rate of one-month LIBOR plus 329 basis points and the mezzanine loan rate is based on a floating rate of one-month LIBOR plus 950 basis points. The Company has entered into LIBOR caps for the periods of the loans. The loans provide for three one-year extension options.
[16]	Mortgage is cross collateralized by seven properties. The Company has agreed, subject to certain conditions, to guarantee repayment of a portion of the loan.
[17]	This construction loan has a maximum borrowing capacity of $28.8 million.
[18]	Mortgage is collateralized by the three properties comprising One River Center.
[19]	The effective interest rate includes amortization of deferred financing costs of 0.122 percent.

Mortgages_Loans_Payable_And_Ot4

Mortgages, Loans Payable And Other Obligations (Schedule Of Principal Payments And Related Weighted Average Interest Rates Of Long Term Debt) (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Debt Disclosure [Abstract]
Scheduled Amortization, 2015	$8,811,000
Scheduled Amortization, 2016	8,311,000
Scheduled Amortization, 2017	7,275,000
Scheduled Amortization, 2018	7,311,000
Scheduled Amortization, 2019	723,000
Scheduled Amortization, Thereafter	6,329,000
Scheduled Amortization, Sub-total	38,760,000
Adjustment for unamortized debt discount/premium and mark-to-market, net, as of December 31, 2013	-11,620,000
Scheduled Ammortization, Total	27,140,000
Principal Maturities, 2015	167,589,000
Principal Maturities, 2016	333,272,000
Principal Maturities, 2017	392,345,000
Principal Maturities, 2018	231,536,000
Principal Maturities, 2019	331,567,000
Principal Maturities, Thereafter	605,205,000
Principal Maturities, Total	2,061,514,000
Total, 2015	176,400,000
Total, 2016	341,583,000
Total, 2017	399,620,000
Total, 2018	238,847,000
Total, 2019	332,290,000
Total, Thereafter	611,534,000
Total, Sub-total	2,100,274,000
Total	$2,088,654,000	$2,362,766,000

MackCali_Realty_LPs_Partners_C2

Mack-Cali Realty, L.P's Partners' Capital (Repurchase Of General Partner Units And Dividend Reinvestment And Stock Purchase Plan) (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended					12 Months Ended		28 Months Ended
	Sep. 30, 2012	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Capacity of share repurchase program		$150,000,000					$150,000,000		$150,000,000
Shares purchased and retired	394,625	394,625	394,625	394,625	394,625	394,625		394,625
Aggregate cost of stock repurchased									11,000,000
Capacity available for additional repurchase of outstanding common stock		139,000,000					139,000,000		139,000,000
Common units purchased from the Company									394,625
Cost of units purchased from the company									11,000,000
Share repurchase program initiation date							Sep-12
Dividend Reinvestment And Stock Purchase Plan [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Common stock reserved for future issuance		5,500,000					5,500,000		5,500,000
Monthly cash investment without restriction, maximum							$5,000

MackCali_Realty_LPs_Partners_C3

Mack-Cali Realty, L.P's Partners' Capital (Stock Option Plans) (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	31-May-13
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Stock option terms	10 years
Weighted average remaining contractual life	4 years 10 months 24 days	8 months 12 days
Share price	$1.71
Proceeds from stock options exercised	$0	$0	$0
Stock options expense	$4,000	$0	$0
2013 Incentive Stock Plan [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance				4,600,000
2004 Incentive Stock Plan [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	2,500,000
Shares issued	0
2000 Employee Plan [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Exercisable time period	5 years
2000 Employee Plan [Member] | Maximum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	4,000,000
2000 Employee Plan [Member] | Minimum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	2,500,000
2000 Director Plan [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Exercisable time period	1 year
2000 Director Plan [Member] | Maximum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	350,000
2000 Director Plan [Member] | Minimum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	200,000
Employee And Director Plan [Member] | Maximum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	4,350,000
Employee And Director Plan [Member] | Minimum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Reserved stocks for issuance	2,700,000

MackCali_Realty_LPs_Partners_C4

Mack-Cali Realty, L.P's Partners' Capital (Restricted Stock Awards And TSR-Based Awards) (Narrative) (Details) (USD $)	12 Months Ended						0 Months Ended	3 Months Ended	0 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		Sep. 12, 2012	Mar. 31, 2014	11-May-15	Dec. 31, 2011
	item
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Unvested performance shares	42,000		63,933
Restricted stock expense	$8,139,000		$2,387,000		$3,642,000
Number of executive officers who departed	2
Shares vested	183,214		149,463		123,877
Unvested restricted stock outstanding	346,946		153,560		134,328					187,447
Awards issued	376,719	[1],[2],[3]	168,841	[4],[5]	70,758	[6]
Shares issued	45,062
Total unrecognized compensation cost	$1,500,000
Total unrecognized compensation cost, period of recognition	1 year 6 months
Restricted Stock [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Unvested restricted stock outstanding	136,946		409,294		134,328
Restricted stock awards unvested shares outstanding performance contingent	210,000
Restricted Stock [Member] | Maximum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Stock compensation vesting period	7 years
Restricted Stock [Member] | Minimum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Stock compensation vesting period	1 year
Ratified Restricted Stock Awards [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Shares vested	109,667
Awards issued							319,667
Ratified Restricted Stock Awards [Member] | Maximum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Stock compensation vesting period	7 years
Ratified Restricted Stock Awards [Member] | Minimum [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Stock compensation vesting period	5 years
Total Stockholder Return Based Awards [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Stock compensation vesting period	4 years
Shares vested								357
Shares granted and vested	528
Awards issued			1,032				5,160
Value of common stock received upon vesting of awards	$1,000
Scenario, Forecast [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Shares vested									84,000
Shares granted and vested									126,000
Scenario, Forecast [Member] | Total Stockholder Return Based Awards [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Shares vested									675
Shares issued									41,811
[1]	Included in the 376,719 Restricted Stock Awards granted in 2014 were 8,211 awards granted to the Corporationbs two executive officers, Anthony Krug and Gary Wagner.
[2]	Includes 42,000 Performance Shares which were legally granted in 2013 for which the 2014 performance goals were set by the Committee on March 31, 2014. Also includes 87,734 shares which were additionally considered granted for accounting purposes to two executive officers in connection with their departure effective March 31, 2014, which vested on April 1, 2014.
[3]	Includes 126,000 Performance Shares which were legally granted in 2013 for which future performance goals had not yet been set by the Committee. These awards were not considered granted for accounting purposes until these goals are set. These were considered granted in 2014 for accounting purposes in connection with the announcement of the departure of Mitchell E. Hersh in the fourth quarter 2014.
[4]	Included in the 168,841 Restricted Stock Awards granted in 2013 were 106,933 awards granted to the Corporationbs four executive officers, Mitchell E. Hersh, Barry Lefkowitz, Roger W. Thomas and Anthony Krug
[5]	Includes 63,933 Performance Shares which were legally granted in 2013 for which the 2013 performance goals were not met, which may be earned if subsequent yearsb performance goals are met.
[6]	Included in the 70,758 Restricted Stock Awards granted in 2012 were 42,273 awards granted to the Corporationbs three executive officers, Mitchell E. Hersh, Barry Lefkowitz and Roger W. Thomas.

MackCali_Realty_LPs_Partners_C5

Mack-Cali Realty, L.P's Partners' Capital (Deferred Stock Compensation Plan For Directors) (Narrative) (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Maximum percentage of retainer fee that directors may defer	100.00%
Deferred stock units earned	20,261	22,392	17,834
Director stock units outstanding	157,730	136,440

MackCali_Realty_LPs_Partners_C6

Mack-Cali Realty, L.P's Partners' Capital (Limited Partners' Capital) (Narrative) (Details)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stockholders' Equity Note [Abstract]
Limited partners common units outstanding	11,083,876	11,864,775	12,141,836

MackCali_Realty_LPs_Partners_C7

Mack-Cali Realty, L.P's Partners' Capital (Earnings Per Unit) (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	10,000	15,000	183,870
Unvested restricted stock outstanding	346,946	153,560	134,328	187,447
Common unit distributions per unit declared	$0.75	$1.35	$1.80
Restricted Stock [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Unvested restricted stock outstanding	136,946	409,294	134,328

MackCali_Realty_LPs_Partners_C8

Mack-Cali Realty, L.P's Partners' Capital (Schedule Of Stock Option Plans) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Shares Under Options - Outstanding, beginning balance	15,000	183,870	183,870
Shares Under Options - Granted	5,000
Shares Under Options - Lapsed or Cancelled	-10,000	-168,870
Shares Under Options - Outstanding, ending balance	10,000	15,000	183,870
Shares Under Options - Options exercisable	5,000
Shares Under Options - Available for grant	4,424,013
Weighted Average Exercise Price - Outstanding, beginning balance	$40.54	$29.51	$29.51
Weighted Average Exercise Price - Granted	$21.25
Weighted Average Exercise Price - Lapsed or Cancelled	$38.07	$28.53
Weighted Average Exercise Price - Outstanding, ending balance	$33.36	$40.54	$29.51
Outstanding stock option price range, lower range	$21.25	$35.59	$28.47
Outstanding stock option price range, upper range	$45.47	$45.47	$45.47

MackCali_Realty_LPs_Partners_C9

Mack-Cali Realty, L.P's Partners' Capital (Schedule Of Weighted Average Assumptions) (Details)	12 Months Ended
	Dec. 31, 2014
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Expected life (in years)	6 years
Risk-free interest rate	1.50%
Volatility	20.26%
Dividend yield	5.65%

Recovered_Sheet6

Mack-Cali Realty, L.P's Partners' Capital (Schedule Of Restricted Stock Awards) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
	item		item		item
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Unvested restricted stock outstanding, beginning balance	153,560		134,328		187,447
Shares, Granted	376,719	[1],[2],[3]	168,841	[4],[5]	70,758	[6]
Shares, Vested	-183,214		-149,463		-123,877
Shares, Forfeited	-119		-146
Unvested restricted stock outstanding, ending balance	346,946		153,560		134,328
Weighted-Average Grant - Date Fair Value, Outstanding beginning balance	$25.20		$31.65		$33.82
Weighted-Average Grant - Date Fair Value, Granted	$20.04	[1],[2],[3]	$23.99	[4],[5]	$25.28	[6]
Weighted-Average Grant - Date Fair Value, Vested	$22.37		$29.63		$31.30
Weighted-Average Grant - Date Fair Value, Forfeited	$26.36		$26.36
Weighted-Average Grant - Date Fair Value, Outstanding ending balance	$21.09		$25.20		$31.65
Number of executive officers that were granted restricted stock awards	2		4		3
Unvested performance shares	42,000		63,933
Number of executive officers who departed	2
Messr Krug And Messr Wagner [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Shares, Granted	8,211
Executive Officer [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Shares, Granted	87,734		106,933		42,273
Messr Hersh [Member]
Share-Based Compensation Arrangement By Share-Based Payment Award [Line Items]
Unvested performance shares	126,000
[1]	Included in the 376,719 Restricted Stock Awards granted in 2014 were 8,211 awards granted to the Corporationbs two executive officers, Anthony Krug and Gary Wagner.
[2]	Includes 42,000 Performance Shares which were legally granted in 2013 for which the 2014 performance goals were set by the Committee on March 31, 2014. Also includes 87,734 shares which were additionally considered granted for accounting purposes to two executive officers in connection with their departure effective March 31, 2014, which vested on April 1, 2014.
[3]	Includes 126,000 Performance Shares which were legally granted in 2013 for which future performance goals had not yet been set by the Committee. These awards were not considered granted for accounting purposes until these goals are set. These were considered granted in 2014 for accounting purposes in connection with the announcement of the departure of Mitchell E. Hersh in the fourth quarter 2014.
[4]	Included in the 168,841 Restricted Stock Awards granted in 2013 were 106,933 awards granted to the Corporationbs four executive officers, Mitchell E. Hersh, Barry Lefkowitz, Roger W. Thomas and Anthony Krug
[5]	Includes 63,933 Performance Shares which were legally granted in 2013 for which the 2013 performance goals were not met, which may be earned if subsequent yearsb performance goals are met.
[6]	Included in the 70,758 Restricted Stock Awards granted in 2012 were 42,273 awards granted to the Corporationbs three executive officers, Mitchell E. Hersh, Barry Lefkowitz and Roger W. Thomas.

Recovered_Sheet7

Mack-Cali Realty, L.P's Partners' Capital (Earnings Per Unit Tables - Basic Computation Of EPU) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Income (loss) from continuing operations	($10,413)	$2,085	$57,347	($17,628)	($60,202)	($46,039)	$8,599	$7,956	$31,391	($89,686)	$37,566
Add: Noncontrolling interest in consolidated joint ventures	21	145	290	322	237	1,838	62	62	778	2,199	330
Income (loss) from continuing operations available to common unitholders									32,169	-87,487	37,896
Income from discontinued operations available to common unitholders										70,628	8,703
Net income (loss) available to common unitholders	($10,392)	$2,230	$57,637	($17,306)	($61,533)	$5,277	$26,246	$13,151	$32,169	($16,859)	$46,599
Weighted average common units									99,999	99,785	99,922
Income (loss) from continuing operations available to common unitholders	($0.10)	$0.02	$0.58	($0.17)	($0.60)	($0.45)	$0.09	$0.08	$0.32	($0.88)	$0.38
Income from discontinued operations available to common unitholders					($0.02)	$0.50	$0.17	$0.05		$0.71	$0.09
Net income (loss) available to common unitholders	($0.10)	$0.02	$0.58	($0.17)	($0.62)	$0.05	$0.26	$0.13	$0.32	($0.17)	$0.47

Recovered_Sheet8

Mack-Cali Realty, L.P's Partners' Capital (Earnings Per Unit Tables - Diluted Computation Of EPU) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Income (loss) from continuing operations available to common unitholders									$32,169	($87,487)	$37,896
Income from discontinued operations for diluted earnings per unit										70,628	8,703
Net income (loss) available to common unitholders									$32,169	($16,859)	$46,599
Weighted average common unit									100,041	99,785	99,996
Income (loss) from continuing operations available to common unitholders	($0.10)	$0.02	$0.58	($0.17)	($0.60)	($0.45)	$0.09	$0.08	$0.32	($0.88)	$0.38
Income from discontinued operations available to common unitholders					($0.02)	$0.50	$0.17	$0.05		$0.71	$0.09
Net income (loss) available to common unitholders	($0.10)	$0.02	$0.58	($0.17)	($0.62)	$0.05	$0.26	$0.13	$0.32	($0.17)	$0.47

Recovered_Sheet9

Mack-Cali Realty, L.P's Partners' Capital (Schedule Of Reconciliation Of Units Used In Basic EPU Calculation To Units Used In Diluted EPU Calculation) (Details)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Mack-Cali Realty, L.P's Partners' Capital [Abstract]
Basic EPU units	99,999	99,785	99,922
Add: Restricted Stock Awards	42		74
Diluted EPU Units	100,041	99,785	99,996

Noncontrolling_Interests_In_Co1

Noncontrolling Interests In Consolidated Joint Ventures (Narrative) (Details) (Participation Rights [Member])	12 Months Ended
	Dec. 31, 2014
	property
Noncontrolling Interest [Line Items]
Number of properties	3
Percentage of excess net cash flow	50.00%
Internal rate of return	10.00%
Future Developments [Member]
Noncontrolling Interest [Line Items]
Number of properties	1

Noncontrolling_Interest_In_Con

Noncontrolling Interest In Consolidated Joint Ventures (Schedule Of Activity Of Noncontrolling Interests) (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Noncontrolling Interest [Line Items]
Balance, value				$1,918,455				$2,068,507	$1,918,455	$2,068,507	$2,154,000
Net income (loss)	-10,413	2,085	57,347	-17,628	-61,770	3,439	26,184	13,089	31,391	-19,058	46,269
Increase in noncontrolling interests									552	1,040	54,835
Balance, value	1,882,011				1,918,455				1,882,011	1,918,455	2,068,507
General Partner Common Unitholders [Member]
Noncontrolling Interest [Line Items]
Balance, value				1,585,100				1,710,372	1,585,100	1,710,372	1,832,977
Net income (loss)									28,567	-14,909	40,922
Balance, value	1,568,098				1,585,100				1,568,098	1,585,100	1,710,372
Limited Partner Common Unitholders [Member]
Noncontrolling Interest [Line Items]
Balance, value				278,072				301,693	278,072	301,693	319,086
Net income (loss)									3,602	-1,950	5,677
Balance, value	258,856				278,072				258,856	278,072	301,693
Noncontrolling Interest In Consolidated Joint Ventures [Member]
Noncontrolling Interest [Line Items]
Balance, value				55,283				56,442	55,283	56,442	1,937
Net income (loss)									-778	-2,199	-330
Increase in noncontrolling interests									552	1,040	54,835
Balance, value	$55,057				$55,283				$55,057	$55,283	$56,442

Employee_Benefit_401k_Plans_An1

Employee Benefit 401(k) Plans And Deferred Retirement Compensation Agreements (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012		11-May-15
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Minimum employee subscription rate, percentage of compensation	1.00%
Maximum employee subscription rate, percentage of compensation	60.00%
Employee pre-tax contributions vested percentage	100.00%
Vesting rate	20.00%
Percentage vested after total service period	100.00%
Employees' vesting rights	Participants are always 100 percent vested in their pre-tax contributions and will begin vesting in any matching or profit sharing contributions made on their behalf after two years of service with the Corporation at a rate of 20 percent per year, becoming 100 percent vested after a total of six years of service with the Corporation.
Expenses for employee benefit plan	$0		$117,000		$7,000
Shares granted	376,719	[1],[2],[3]	168,841	[4],[5]	70,758	[6]
Shares issued for accrued dividends	966
Period upon which stock units become payable following a triggering event	30 days
Minimum [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Employer contribution vesting period	2 years
Maximum [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Employer contribution vesting period	6 years
Messr Hersh [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Amount of annual employer contribution to deferred retirement compensation	500,000
Messr Hersh [Member] | Scenario, Forecast [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Cash payment on separation date							2,300,000
Messr Lefkowitz And Messr Thomas [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Expenses for employee benefit plan	1,200,000
Deferred Retirement Compensation Units [Member]
Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items]
Expenses for employee benefit plan	$2,957,000		$595,000		$0
Shares granted	36,347
[1]	Included in the 376,719 Restricted Stock Awards granted in 2014 were 8,211 awards granted to the Corporationbs two executive officers, Anthony Krug and Gary Wagner.
[2]	Includes 42,000 Performance Shares which were legally granted in 2013 for which the 2014 performance goals were set by the Committee on March 31, 2014. Also includes 87,734 shares which were additionally considered granted for accounting purposes to two executive officers in connection with their departure effective March 31, 2014, which vested on April 1, 2014.
[3]	Includes 126,000 Performance Shares which were legally granted in 2013 for which future performance goals had not yet been set by the Committee. These awards were not considered granted for accounting purposes until these goals are set. These were considered granted in 2014 for accounting purposes in connection with the announcement of the departure of Mitchell E. Hersh in the fourth quarter 2014.
[4]	Included in the 168,841 Restricted Stock Awards granted in 2013 were 106,933 awards granted to the Corporationbs four executive officers, Mitchell E. Hersh, Barry Lefkowitz, Roger W. Thomas and Anthony Krug
[5]	Includes 63,933 Performance Shares which were legally granted in 2013 for which the 2013 performance goals were not met, which may be earned if subsequent yearsb performance goals are met.
[6]	Included in the 70,758 Restricted Stock Awards granted in 2012 were 42,273 awards granted to the Corporationbs three executive officers, Mitchell E. Hersh, Barry Lefkowitz and Roger W. Thomas.

Disclosure_Of_Fair_Value_Of_Fi1

Disclosure Of Fair Value Of Financial Instruments (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Disclosure Of Fair Value Of Financial Instruments [Abstract]
Fair value of Company's long-term debt	$2,133,214,000	$2,407,802,000
Book value of Company's long-term debt	$2,088,654,000	$2,362,766,000

Commitments_And_Contingencies_1

Commitments And Contingencies (Tax Abatement Agreements) (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Harborside Financial Center Plaza 4A [Member]
Commitments And Contingencies [Line Items]
Project period	20 years
Percentage of PILOT on project costs	2.00%
Total project costs	$49,500,000
Payments in lieu of property taxes (PILOT)	990,000	990,000	990,000
Harborside Financial Center Plaza 5 [Member]
Commitments And Contingencies [Line Items]
Project period	20 years
Percentage of PILOT on project costs	2.00%
Total project costs	170,900,000
Payments in lieu of property taxes (PILOT)	$3,400,000	$3,400,000	$3,400,000
Port Imperial South 4/5 [Member]
Commitments And Contingencies [Line Items]
Project period	5 years
Period of real estate taxes phase in	5 years
Park Square [Member]
Commitments And Contingencies [Line Items]
Period of partial abatement of real estate taxes	4 years

Commitments_And_Contingencies_2

Commitments And Contingencies (Ground Lease Agreements) (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Commitments And Contingencies [Abstract]
Ground lease expense incurred	$406,000	$406,000	$406,000

Commitments_And_Contingencies_3

Commitments And Contingencies (Roseland Contingent Consideration) (Narrative) (Details) (USD $)	3 Months Ended								12 Months Ended			0 Months Ended			1 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 17, 2014	Mar. 21, 2014	Jan. 25, 2013	Apr. 30, 2013	Oct. 23, 2012
Business Acquisition, Contingent Consideration [Line Items]
Fair value of contingent consideration					$405,000					$405,000
Interest and other investment income	1,399,000	908,000	922,000	386,000	1,616,000	187,000	1,094,000	6,000	3,615,000	2,903,000	34,000
Earn out paid									5,228,000	2,755,000
Roseland Partners, L.L.C. [Member]
Business Acquisition, Contingent Consideration [Line Items]
Fair value of contingent consideration	900,000								900,000							10,000,000
Business acquisition, contingent cash payment	15,600,000								15,600,000
Business acquisition, earn out period									3 years
Interest and other investment income									1,500,000	2,300,000
Earn out paid												1,400,000	1,400,000	2,800,000
Contingent purchase price measurement period									33 months
Amount of escrow released									34,000,000						6,700,000
Roseland Assets [Member] | Roseland Partners, L.L.C. [Member]
Business Acquisition, Contingent Consideration [Line Items]
Fair value of contingent consideration	6,300,000								6,300,000
Business acquisition, contingent cash payment	8,600,000								8,600,000
Completion Of Certain Developments [Member] | Roseland Partners, L.L.C. [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition, contingent cash payment	2,800,000								2,800,000
Start Of Construction On Certain Developments [Member] | Roseland Partners, L.L.C. [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition, contingent cash payment	2,800,000								2,800,000
Completion/Start Of Certain Developments [Member] | Roseland Partners, L.L.C. [Member] | Minimum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Probability of occurrence	92.00%								92.00%
Completion/Start Of Certain Developments [Member] | Roseland Partners, L.L.C. [Member] | Maximum [Member]
Business Acquisition, Contingent Consideration [Line Items]
Probability of occurrence	99.00%								99.00%
Obtaining Of Tax Credits/Grants [Member] | Roseland Partners, L.L.C. [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition, contingent cash payment	3,000,000								3,000,000
Probability of occurrence	50.00%								50.00%
Earn out paid		1,000,000
Total Return To Shareholders [Member] | Roseland Partners, L.L.C. [Member]
Business Acquisition, Contingent Consideration [Line Items]
Fair value of contingent consideration	3,700,000								3,700,000
Business acquisition, contingent cash payment	7,000,000								7,000,000
Business acquisition, earn out period									3 years
Failure To Achieve A Certain Level Of Fee Revenue [Member]
Business Acquisition, Contingent Consideration [Line Items]
Business acquisition, contingent cash payment	$2,000,000								$2,000,000

Commitments_And_Contingencies_4

Commitments And Contingencies (Departure Of Executive Vice Presidents) (Narrative) (Details) (USD $)	12 Months Ended			6 Months Ended	0 Months Ended	3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	11-May-15	Mar. 31, 2014
Commitments And Contingencies [Line Items]
Severance benefits	$23,800,000
Restricted stock units vested	183,214	149,463	123,877
Shares issued	45,062
Accounts payable, accrued expenses and other liabilities	126,971,000	121,286,000
Employee Severance [Member]
Commitments And Contingencies [Line Items]
Accounts payable, accrued expenses and other liabilities	11,600,000
Messr Lefkowitz [Member]
Commitments And Contingencies [Line Items]
Severance benefits	3,400,000
Stock options vested	11,457
Restricted stock units vested	68,667
Period for continuation of health insurance	48 months
Messr Thomas [Member]
Commitments And Contingencies [Line Items]
Severance benefits	3,100,000
Stock options vested	33,605
Restricted stock units vested	41,000
Period for continuation of health insurance	48 months
Consulting payment				300,000
Messr Hersh [Member]
Commitments And Contingencies [Line Items]
Period after Separation Date	6 months 1 day
Scenario, Forecast [Member]
Commitments And Contingencies [Line Items]
Restricted stock units vested					84,000
Scenario, Forecast [Member] | Messr Hersh [Member]
Commitments And Contingencies [Line Items]
Severance benefits					8,000,000
Restricted stock units vested					210,000
Period for continuation of health insurance					48 months
Cash payment					504,000
Termination payment multiplier					210,000
Deferred retirement compensation contribution					2,311,792
Shares issued					41,811
Total Stockholder Return Based Awards [Member]
Commitments And Contingencies [Line Items]
Restricted stock units vested						357
Total Stockholder Return Based Awards [Member] | Scenario, Forecast [Member]
Commitments And Contingencies [Line Items]
Restricted stock units vested					675
Shares issued					41,811
Total Stockholder Return Based Awards [Member] | Scenario, Forecast [Member] | Messr Hersh [Member]
Commitments And Contingencies [Line Items]
Restricted stock units vested					675

Commitments_And_Contingencies_5

Commitments And Contingencies (Roseland Transaction Modifications) (Narrative) (Details) (USD $)

3 Months Ended

12 Months Ended

0 Months Ended

6 Months Ended

0 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Oct. 23, 2015

Oct. 28, 2014

Apr. 24, 2015

Sep. 17, 2014

Mar. 21, 2014

Jan. 25, 2013

item

Commitments And Contingencies [Line Items]

Severance benefits

$23,800,000

Percentage of ownership interest

[1],[2],[3]

[1],[2],[3]

Earn out paid

5,228,000

2,755,000

General and administrative

23,950,000

12,665,000

13,673,000

22,881,000

10,447,000

12,151,000

13,111,000

11,973,000

73,169,000

47,682,000

47,664,000

Accounts payable, accrued expenses and other liabilities

126,971,000

121,286,000

126,971,000

121,286,000

Minimum [Member]

Commitments And Contingencies [Line Items]

Percentage of ownership interest

7.50%

7.50%

Messieur Goldberg [Member]

Commitments And Contingencies [Line Items]

Consulting service period

1 year

Messieur Klatt And Messieur Goldberg [Member]

Commitments And Contingencies [Line Items]

Healthcare continuation period

1 year

Scenario, Forecast [Member] | Messieur Goldberg [Member]

Commitments And Contingencies [Line Items]

Consulting payment

400,000

Number of installments

4

Scenario, Forecast [Member] | Messieur Klatt And Messieur Goldberg [Member]

Commitments And Contingencies [Line Items]

Severance benefits

750,000

500,000

Roseland Partners, L.L.C. [Member]

Commitments And Contingencies [Line Items]

Earn out paid

1,400,000

1,400,000

2,800,000

General and administrative

1,100,000

Accounts payable, accrued expenses and other liabilities

1,000,000

1,000,000

Roseland Partners, L.L.C. [Member] | Messr Tycher [Member] | Minimum [Member]

Commitments And Contingencies [Line Items]

Percentage of ownership interest

50.00%

50.00%

Roseland Partners, L.L.C. [Member] | Obtaining Of Tax Credits/Grants [Member]

Commitments And Contingencies [Line Items]

Earn out paid

$1,000,000

[1]

Company's effective ownership % represents the Company's entitlement to residual distributions after payments of priority returns, where applicable.

[2]

The Companybs equity interests in the joint ventures will be subordinated to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally.

[3]

Includes the Companybs pari-passu interests of $6.2 million in five properties and Companybs subordinated equity interests to Keystone Entities receiving a 15 percent internal rate of return (bIRRb) after which the Company will receive a 10 percent IRR on its subordinate equity and then all profit will be split equally (See Note 3: Real Estate Transactions - Sales).

Commitments_And_Contingencies_6

Commitments And Contingencies (Joint Venture Interests Agreement And Other) (Narrative) (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Jul. 31, 2012
		sqft
Property Lock-Ups [Member]
Commitments And Contingencies [Line Items]
Number of properties	7
Properties aggregate net book value	$125.30
Expiration year	2016
Property Lock-Ups Expired [Member]
Commitments And Contingencies [Line Items]
Number of properties	110
Properties aggregate net book value	1,300
Wegmans Food Markets, Inc. [Member]
Commitments And Contingencies [Line Items]
Total project costs	25.3
Costs of the project incurred	$8
Delivery date to tenant	late 2016
Area of property (in square feet)		140,000

Commitments_And_Contingencies_7

Commitments And Contingencies (Future Minimum Rental Payments Of Ground Leases) (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Commitments And Contingencies [Abstract]
2015	$371
2016	371
2017	267
2018	232
2019	235
2020 through 2084	15,584
Total	$17,060

Tenant_Leases_Details

Tenant Leases (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014
Property Subject to or Available for Operating Lease [Line Items]
2015	454,461
2016	420,115
2017	368,666
2018	288,977
2019	234,368
2020 and thereafter	934,117
Total	2,700,704
Tenant Leases [Member]
Property Subject to or Available for Operating Lease [Line Items]
Operating leases with various expiration dates through year	31-Dec-35
Multi-Family Properties [Member]
Property Subject to or Available for Operating Lease [Line Items]
Lease period	1 year

Segment_Reporting_Narrative_De

Segment Reporting (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of business segments	3
Foreign Locations [Member]
Segment Reporting Information [Line Items]
Revenue	$0	$0	$0
Long lived assets	$0	$0

Segment_Reporting_Selected_Res

Segment Reporting (Selected Results Of Operations And Asset Information) (Details) (USD $)	3 Months Ended										12 Months Ended
	Dec. 31, 2014		Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Total revenues	$151,414,000		$155,489,000	$160,300,000	$169,596,000	$165,267,000		$162,505,000	$168,346,000	$170,913,000	$636,799,000		$667,031,000		$650,632,000
Total operating and interest expenses											484,761,000		460,615,000	[1]	428,017,000	[1]
Equity in earnings (loss) of unconsolidated joint ventures	-363,000		-1,268,000	443,000	-1,235,000	-268,000		-229,000	-80,000	-1,750,000	-2,423,000		-2,327,000		4,089,000
Net operating income (loss)											149,615,000		204,089,000	[2]	226,704,000
Total assets	4,192,247,000					4,515,328,000					4,192,247,000		4,515,328,000
Total long-lived assets	3,670,704,000					3,868,193,000	[3]				3,670,704,000		3,868,193,000	[3]
Investments in unconsolidated joint ventures	247,468,000					181,129,000					247,468,000		181,129,000
Real Estate - Commercial And Other [Member]
Segment Reporting Information [Line Items]
Total revenues											585,491,000		621,352,000		635,278,000
Total operating and interest expenses											295,416,000		285,755,000	[1]	276,700,000	[1]
Equity in earnings (loss) of unconsolidated joint ventures											4,236,000		6,280,000		5,564,000
Net operating income (loss)											294,311,000		341,877,000	[2]	364,142,000
Total assets	3,636,126,000					3,886,574,000					3,636,126,000		3,886,574,000
Total long-lived assets	3,344,840,000					3,620,494,000	[3]				3,344,840,000		3,620,494,000	[3]
Investments in unconsolidated joint ventures	81,649,000					53,160,000					81,649,000		53,160,000
Real Estate - Multi Family [Member]
Segment Reporting Information [Line Items]
Total revenues											24,971,000		12,792,000
Total operating and interest expenses											12,235,000		6,482,000	[1]
Equity in earnings (loss) of unconsolidated joint ventures											-8,790,000		-10,615,000		-1,475,000
Net operating income (loss)											3,946,000		-4,305,000	[2]	-1,475,000
Total assets	492,362,000					377,237,000					492,362,000		377,237,000
Total long-lived assets	318,524,000					240,501,000	[3]				318,524,000		240,501,000	[3]
Investments in unconsolidated joint ventures	164,912,000					127,276,000					164,912,000		127,276,000
Multi Family Services [Member]
Segment Reporting Information [Line Items]
Total revenues											30,533,000	[4]	25,710,000	[5]	4,465,000
Total operating and interest expenses											38,377,000		32,415,000	[1]	5,195,000	[1]
Equity in earnings (loss) of unconsolidated joint ventures											2,131,000		2,008,000
Net operating income (loss)											-5,713,000		-4,697,000	[2]	-730,000
Total assets	11,158,000					10,488,000					11,158,000		10,488,000
Total long-lived assets	3,858,000					3,468,000	[3]				3,858,000		3,468,000	[3]
Investments in unconsolidated joint ventures	907,000					693,000					907,000		693,000
Fee revenue											2,300,000		2,200,000
Corporate And Other [Member]
Segment Reporting Information [Line Items]
Total revenues											-4,196,000	[6]	7,177,000	[6]	10,889,000	[6]
Total operating and interest expenses											138,733,000	[6]	135,963,000	[1],[6]	146,122,000	[1],[6]
Net operating income (loss)											-142,929,000	[6]	-128,786,000	[2],[6]	-135,233,000	[6]
Total assets	52,601,000	[6]				241,029,000	[6]				52,601,000	[6]	241,029,000	[6]
Total long-lived assets	$3,482,000	[6]				$3,730,000	[3],[6]				$3,482,000	[6]	$3,730,000	[3],[6]
[1]	Total operating and interest expenses represent the sum of: real estate taxes; utilities; operating services; direct construction costs; real estate services expenses; general and administrative and interest expense (net of interest income). All interest expense, net of interest and other investment income, (including for property-level mortgages) is excluded from segment amounts and classified in Corporate & Other for all periods.
[2]	Net operating income represents total revenues less total operating and interest expenses (as defined in Note bab), plus equity in earnings (loss) of unconsolidated joint ventures, for the period.
[3]	Long-lived assets are comprised of net investment in rental property, unbilled rents receivable and goodwill.
[4]	Includes $2.3 million of fees earned for this period from the multi-family real estate segment, which are eliminated in consolidation.
[5]	Includes $2.2 million of fees earned for this period from the multi-family real estate segment, which are eliminated in consolidation.
[6]	Corporate & Other represents all corporate-level items (including interest and other investment income, interest expense, non-property general and administrative expense, construction services revenue and direct construction costs) as well as intercompany eliminations necessary to reconcile to consolidated Company totals.

Segment_Reporting_Schedule_Of_

Segment Reporting (Schedule Of Reconciliation Of Net Operating Income To Income From Continuing Operations) (Details) (USD $)	3 Months Ended										12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012
Segment Reporting [Abstract]
Net operating income											$149,615	$204,089	[1]	$226,704
Depreciation and amortization	-40,811	-41,983	-44,711	-44,985	-47,666		-46,087		-45,665	-43,348	-172,490	-182,766		-174,333
Realized gains (losses) on disposition of rental property, net		264	54,584								54,848
Loss from early extinguishment of debt	-582				-156						-582	-156		-4,960
Impairments					-62,153	[2],[3]	-48,700	[2]				-110,853		-9,845
Income from continuing operations	-10,413	2,085	57,347	-17,628	-60,202		-46,039		8,599	7,956	31,391	-89,686		37,566
Income from discontinued operations					-9		2,157		4,530	5,133		11,811		21,878
Loss from early extinguishment of debt												-703
Realized gains (losses) and unrealized losses on disposition of rental property and impairments, net					-1,559	[4]	47,321		13,758			59,520		-13,175
Total discontinued operations, net					-1,568		49,478		17,585	5,133		70,628		8,703
Net income (loss)	-10,413	2,085	57,347	-17,628	-61,770		3,439		26,184	13,089	31,391	-19,058		46,269
Noncontrolling interest in consolidated joint ventures	21	145	290	322	237		1,838		62	62	778	2,199		330
Net income (loss) available to common unitholders	($10,392)	$2,230	$57,637	($17,306)	($61,533)		$5,277		$26,246	$13,151	$32,169	($16,859)		$46,599
[1]	Net operating income represents total revenues less total operating and interest expenses (as defined in Note bab), plus equity in earnings (loss) of unconsolidated joint ventures, for the period.
[2]	Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions - Impairments on Properties Held and Used.
[3]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[4]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.

Related_Party_Transactions_Det

Related Party Transactions (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Revenue under lease	$516,727,000	$540,165,000	$535,822,000
RG [Member]
Related Party Transaction [Line Items]
Revenue under lease	2,401,000	2,272,000	728,000
Leased Property [Member]
Related Party Transaction [Line Items]
Number of real estate properties	1
Leased Property [Member] | Mack [Member]
Related Party Transaction [Line Items]
Square Feet	7,034
Revenue under lease	$231,000	$226,000	$238,000

Condensed_Quarterly_Financial_2

Condensed Quarterly Financial information calc (Details) (USD $)	3 Months Ended										12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Total revenues	$151,414,000	$155,489,000	$160,300,000	$169,596,000	$165,267,000		$162,505,000		$168,346,000	$170,913,000	$636,799,000	$667,031,000	$650,632,000
Operating and other expenses	64,177,000	64,374,000	65,788,000	81,854,000	67,862,000		64,467,000		58,900,000	63,245,000
Direct construction costs							609,000		6,511,000	7,825,000		14,945,000	12,647,000
Real estate service salaries	5,923,000	6,933,000	6,571,000	6,709,000	6,907,000		5,552,000		5,304,000	4,953,000
General and administrative	23,950,000	12,665,000	13,673,000	22,881,000	10,447,000		12,151,000		13,111,000	11,973,000	73,169,000	47,682,000	47,664,000
Depreciation and amortization	40,811,000	41,983,000	44,711,000	44,985,000	47,666,000		46,087,000		45,665,000	43,348,000	172,490,000	182,766,000	174,333,000
Impairments					62,153,000	[1],[2]	48,700,000	[1]				110,853,000	9,845,000
Total expenses	134,861,000	125,955,000	130,743,000	156,429,000	195,035,000		177,566,000		129,491,000	131,344,000	547,988,000	633,436,000	490,190,000
Operating Income	16,553,000	29,534,000	29,557,000	13,167,000	-29,768,000		-15,061,000		38,855,000	39,569,000	88,811,000	33,595,000	160,442,000
Interest expense	-27,420,000	-27,353,000	-28,159,000	-29,946,000	-31,626,000		-30,936,000		-31,270,000	-29,869,000	-112,878,000	-123,701,000	-122,039,000
Interest and other investment income	1,399,000	908,000	922,000	386,000	1,616,000		187,000		1,094,000	6,000	3,615,000	2,903,000	34,000
Equity in earnings (loss) of unconsolidated joint ventures	-363,000	-1,268,000	443,000	-1,235,000	-268,000		-229,000		-80,000	-1,750,000	-2,423,000	-2,327,000	4,089,000
Realized gains (losses) on disposition of rental property, net		264,000	54,584,000								54,848,000
Loss from early extinguishment of debt	-582,000				-156,000						-582,000	-156,000	-4,960,000
Total other (expense) income	-26,966,000	-27,449,000	27,790,000	-30,795,000	-30,434,000		-30,978,000		-30,256,000	-31,613,000	-57,420,000	-123,281,000	-122,876,000
Income (loss) from continuing operations	-10,413,000	2,085,000	57,347,000	-17,628,000	-60,202,000		-46,039,000		8,599,000	7,956,000	31,391,000	-89,686,000	37,566,000
Discontinued operations:
Income (loss) from discontinued operations					-9,000		2,157,000		4,530,000	5,133,000		11,811,000	21,878,000
Loss from early extinguishment of debt									-703,000			-703,000
Realized gains (losses) and unrealized losses on disposition of rental property and impairments, net					-1,559,000	[3]	47,321,000		13,758,000			59,520,000	-13,175,000
Total discontinued operations, net					-1,568,000		49,478,000		17,585,000	5,133,000		70,628,000	8,703,000
Net income (loss)	-10,413,000	2,085,000	57,347,000	-17,628,000	-61,770,000		3,439,000		26,184,000	13,089,000	31,391,000	-19,058,000	46,269,000
Noncontrolling interest in consolidated joint ventures	21,000	145,000	290,000	322,000	237,000		1,838,000		62,000	62,000	778,000	2,199,000	330,000
Net income (loss) available to common unitholders	-10,392,000	2,230,000	57,637,000	-17,306,000	-61,533,000		5,277,000		26,246,000	13,151,000	32,169,000	-16,859,000	46,599,000
Basic earnings per common share:
Income (loss) from continuing operations	($0.10)	$0.02	$0.58	($0.17)	($0.60)		($0.45)		$0.09	$0.08	$0.32	($0.88)	$0.38
Discontinued operations					($0.02)		$0.50		$0.17	$0.05		$0.71	$0.09
Net income (loss) available to common unitholders	($0.10)	$0.02	$0.58	($0.17)	($0.62)		$0.05		$0.26	$0.13	$0.32	($0.17)	$0.47
Diluted earnings per common unit:
Income (loss) from continuing operations	($0.10)	$0.02	$0.58	($0.17)	($0.60)		($0.45)		$0.09	$0.08	$0.32	($0.88)	$0.38
Discontinued operations					($0.02)		$0.50		$0.17	$0.05		$0.71	$0.09
Net income (loss) available to common shareholders	($0.10)	$0.02	$0.58	($0.17)	($0.62)		$0.05		$0.26	$0.13	$0.32	($0.17)	$0.47
Dividends declared per common share	$0.15	$0.15	$0.15	$0.30	$0.30		$0.30		$0.30	$0.45
Restatement Adjustment [Member]
Impairments					1,260,000
Realized gains (losses) on disposition of rental property, net					$1,559,000
[1]	Amounts for the year ended December 31, 2013 relate to impairment charges as further described in Note 3: Real Estate Transactions - Impairments on Properties Held and Used.
[2]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,260,000 to correct an error in the measurement of its impairment charges on certain properties in the third quarter of 2013. In the third quarter, in measuring the impairments on these properties, the Company did not include certain tenant improvement amounts to be paid for in-place leases in its discounted cash flows used to measure fair value and, as a result, should have recognized larger impairment charges by this aggregate amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.
[3]	During the quarter ended December 31, 2013, the Company identified and recorded an out-of-period adjustment to reflect a charge of $1,559,000 to correct an error in its calculation of the gain on sale of rental property on a transaction that closed in the third quarter of 2013. In the third quarter, in recording the gain on the sale transaction, the Company did not include the full consolidated carrying amount of the property in computing the gain and, as a result, should have recognized a smaller gain by this amount. The Company has determined that this adjustment was not material to the quarter ended December 31, 2013 or the prior interim period.

Real_Estate_Investments_And_Ac1

Real Estate Investments And Accumulated Depreciation (Schedule Of Real Estate Investments And Accumulated Depreciation) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Related Encumbrances	$756,910,000
Initial Costs, Land	778,751,000
Initial Costs, Building and Improvements	3,510,501,000
Costs Capitalized Subsequent to Acquisition	668,927,000
Gross Amount at Which Carried at Close of Period, Land	760,855,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,197,324,000
Total	4,958,179,000		5,129,933,000	5,379,436,000	5,279,770,000
Accumulated Depreciation	1,414,305,000		1,400,988,000	1,478,214,000	1,409,163,000
Aggregate cost for federal income tax purposes	3,200,000,000
Office [Member] | One Bridge Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	1996
Initial Costs, Land	2,439,000
Initial Costs, Building and Improvements	24,462,000
Costs Capitalized Subsequent to Acquisition	7,701,000
Gross Amount at Which Carried at Close of Period, Land	2,439,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	32,163,000	[1]
Total	34,602,000
Accumulated Depreciation	14,550,000	[2]
Office [Member] | 2115 Linwood Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	1998
Initial Costs, Land	474,000
Initial Costs, Building and Improvements	4,419,000
Costs Capitalized Subsequent to Acquisition	5,870,000
Gross Amount at Which Carried at Close of Period, Land	474,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	10,289,000	[1]
Total	10,763,000
Accumulated Depreciation	3,629,000	[2]
Office [Member] | 210 Clay Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1978
Acquired	2009
Related Encumbrances	13,330,000
Initial Costs, Land	2,300,000
Initial Costs, Building and Improvements	11,189,000
Costs Capitalized Subsequent to Acquisition	-9,034,000
Gross Amount at Which Carried at Close of Period, Land	781,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,674,000	[1]
Total	4,455,000
Accumulated Depreciation	771,000	[2]
Office [Member] | 135 Chestnut Ridge Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	1997
Initial Costs, Land	2,587,000
Initial Costs, Building and Improvements	10,350,000
Costs Capitalized Subsequent to Acquisition	1,783,000
Gross Amount at Which Carried at Close of Period, Land	2,588,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	12,132,000	[1]
Total	14,720,000
Accumulated Depreciation	5,104,000	[2]
Office [Member] | 15 East Midland Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1997
Related Encumbrances	12,615,000
Initial Costs, Land	10,375,000
Initial Costs, Building and Improvements	41,497,000
Costs Capitalized Subsequent to Acquisition	2,388,000
Gross Amount at Which Carried at Close of Period, Land	10,374,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	43,886,000	[1]
Total	54,260,000
Accumulated Depreciation	18,222,000	[2]
Office [Member] | 140 East Ridgewood [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	1997
Related Encumbrances	11,887,000
Initial Costs, Land	7,932,000
Initial Costs, Building and Improvements	31,463,000
Costs Capitalized Subsequent to Acquisition	7,012,000
Gross Amount at Which Carried at Close of Period, Land	7,932,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	38,475,000	[1]
Total	46,407,000
Accumulated Depreciation	16,309,000	[2]
Office [Member] | 461 From Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1997
Initial Costs, Land	13,194,000
Initial Costs, Building and Improvements	52,778,000
Costs Capitalized Subsequent to Acquisition	4,233,000
Gross Amount at Which Carried at Close of Period, Land	13,194,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	57,011,000	[1]
Total	70,205,000
Accumulated Depreciation	22,956,000	[2]
Office [Member] | 650 From Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1978
Acquired	1997
Related Encumbrances	22,804,000
Initial Costs, Land	10,487,000
Initial Costs, Building and Improvements	41,949,000
Costs Capitalized Subsequent to Acquisition	7,984,000
Gross Amount at Which Carried at Close of Period, Land	10,487,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	49,933,000	[1]
Total	60,420,000
Accumulated Depreciation	20,867,000	[2]
Office [Member] | 61 South Paramus Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1997
Related Encumbrances	22,319,000
Initial Costs, Land	9,005,000
Initial Costs, Building and Improvements	36,018,000
Costs Capitalized Subsequent to Acquisition	7,913,000
Gross Amount at Which Carried at Close of Period, Land	9,005,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	43,931,000	[1]
Total	52,936,000
Accumulated Depreciation	19,029,000	[2]
Office [Member] | 120 West Passaic Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1972
Acquired	1997
Initial Costs, Land	1,354,000
Initial Costs, Building and Improvements	5,415,000
Costs Capitalized Subsequent to Acquisition	431,000
Gross Amount at Which Carried at Close of Period, Land	1,357,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,843,000	[1]
Total	7,200,000
Accumulated Depreciation	2,424,000	[2]
Office [Member] | 365 West Passaic Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1976
Acquired	1997
Related Encumbrances	11,887,000
Initial Costs, Land	4,148,000
Initial Costs, Building and Improvements	16,592,000
Costs Capitalized Subsequent to Acquisition	4,442,000
Gross Amount at Which Carried at Close of Period, Land	4,148,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	21,034,000	[1]
Total	25,182,000
Accumulated Depreciation	9,216,000	[2]
Office [Member] | 395 West Passaic Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1979
Acquired	2006
Initial Costs, Land	2,550,000
Initial Costs, Building and Improvements	17,131,000
Costs Capitalized Subsequent to Acquisition	437,000
Gross Amount at Which Carried at Close of Period, Land	2,550,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	17,568,000	[1]
Total	20,118,000
Accumulated Depreciation	3,717,000	[2]
Office [Member] | 1 Lake Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1994
Acquired	1997
Related Encumbrances	40,756,000
Initial Costs, Land	13,952,000
Initial Costs, Building and Improvements	55,812,000
Costs Capitalized Subsequent to Acquisition	-37,797,000
Gross Amount at Which Carried at Close of Period, Land	6,268,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	25,699,000	[1]
Total	31,967,000
Accumulated Depreciation	10,336,000	[2]
Office [Member] | 10 Mountainview Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1998
Initial Costs, Land	4,240,000
Initial Costs, Building and Improvements	20,485,000
Costs Capitalized Subsequent to Acquisition	4,480,000
Gross Amount at Which Carried at Close of Period, Land	4,240,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	24,965,000	[1]
Total	29,205,000
Accumulated Depreciation	10,456,000	[2]
Office [Member] | 400 Chestnut Ridge Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Acquired	1997
Initial Costs, Land	4,201,000
Initial Costs, Building and Improvements	16,802,000
Costs Capitalized Subsequent to Acquisition	-6,650,000
Gross Amount at Which Carried at Close of Period, Land	2,312,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	12,041,000	[1]
Total	14,353,000
Accumulated Depreciation	6,431,000	[2]
Office [Member] | 50 Tice Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	1994
Related Encumbrances	23,289,000
Initial Costs, Land	4,500,000
Costs Capitalized Subsequent to Acquisition	26,578,000
Gross Amount at Which Carried at Close of Period, Land	4,500,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	26,578,000	[1]
Total	31,078,000
Accumulated Depreciation	18,326,000	[2]
Office [Member] | 300 Tice Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	1996
Initial Costs, Land	5,424,000
Initial Costs, Building and Improvements	29,688,000
Costs Capitalized Subsequent to Acquisition	5,970,000
Gross Amount at Which Carried at Close of Period, Land	5,424,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	35,658,000	[1]
Total	41,082,000
Accumulated Depreciation	15,466,000	[2]
Office [Member] | 150 J.F. Kennedy Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Acquired	1997
Initial Costs, Land	12,606,000
Initial Costs, Building and Improvements	50,425,000
Costs Capitalized Subsequent to Acquisition	8,846,000
Gross Amount at Which Carried at Close of Period, Land	12,606,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	59,271,000
Total	71,877,000
Accumulated Depreciation	24,979,000
Office [Member] | 4 Becker Farm Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2009
Related Encumbrances	39,421,000
Initial Costs, Land	5,600,000
Initial Costs, Building and Improvements	38,285,000
Costs Capitalized Subsequent to Acquisition	-9,054,000
Gross Amount at Which Carried at Close of Period, Land	4,271,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	30,560,000
Total	34,831,000
Accumulated Depreciation	5,854,000
Office [Member] | 5 Becker Farm Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Acquired	2009
Related Encumbrances	13,867,000
Initial Costs, Land	2,400,000
Initial Costs, Building and Improvements	11,885,000
Costs Capitalized Subsequent to Acquisition	-5,626,000
Gross Amount at Which Carried at Close of Period, Land	1,492,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,167,000
Total	8,659,000
Accumulated Depreciation	1,128,000
Office [Member] | 6 Becker Farm Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2009
Related Encumbrances	14,226,000
Initial Costs, Land	2,600,000
Initial Costs, Building and Improvements	15,548,000
Costs Capitalized Subsequent to Acquisition	-4,667,000
Gross Amount at Which Carried at Close of Period, Land	1,883,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	11,598,000
Total	13,481,000
Accumulated Depreciation	2,113,000
Office [Member] | 101 Eisenhower Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Acquired	1994
Initial Costs, Land	228,000
Costs Capitalized Subsequent to Acquisition	21,542,000
Gross Amount at Which Carried at Close of Period, Land	228,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	21,542,000
Total	21,770,000
Accumulated Depreciation	12,971,000
Office [Member] | 103 Eisenhower Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1994
Costs Capitalized Subsequent to Acquisition	16,519,000
Gross Amount at Which Carried at Close of Period, Land	2,300,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	14,219,000
Total	16,519,000
Accumulated Depreciation	8,961,000
Office [Member] | 105 Eisenhower Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2001
Acquired	2001
Initial Costs, Land	4,430,000
Initial Costs, Building and Improvements	42,898,000
Costs Capitalized Subsequent to Acquisition	5,289,000
Gross Amount at Which Carried at Close of Period, Land	3,835,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	48,782,000
Total	52,617,000
Accumulated Depreciation	22,007,000
Office [Member] | 75 Livingston Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	2009
Related Encumbrances	10,888,000
Initial Costs, Land	1,900,000
Initial Costs, Building and Improvements	6,312,000
Costs Capitalized Subsequent to Acquisition	-1,637,000
Gross Amount at Which Carried at Close of Period, Land	1,281,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,294,000
Total	6,575,000
Accumulated Depreciation	1,045,000
Office [Member] | 85 Livingston Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	2009
Related Encumbrances	15,243,000
Initial Costs, Land	2,500,000
Initial Costs, Building and Improvements	14,238,000
Costs Capitalized Subsequent to Acquisition	-6,542,000
Gross Amount at Which Carried at Close of Period, Land	1,471,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,725,000
Total	10,196,000
Accumulated Depreciation	1,614,000
Office [Member] | Harborside Plaza 1 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	1996
Initial Costs, Land	3,923,000
Initial Costs, Building and Improvements	51,013,000
Costs Capitalized Subsequent to Acquisition	27,926,000
Gross Amount at Which Carried at Close of Period, Land	3,923,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	78,939,000
Total	82,862,000
Accumulated Depreciation	36,168,000
Office [Member] | Harborside Plaza 2 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1996
Initial Costs, Land	17,655,000
Initial Costs, Building and Improvements	101,546,000
Costs Capitalized Subsequent to Acquisition	21,449,000
Gross Amount at Which Carried at Close of Period, Land	12,844,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	127,806,000
Total	140,650,000
Accumulated Depreciation	54,391,000
Office [Member] | Harborside Plaza 3 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1996
Initial Costs, Land	17,655,000
Initial Costs, Building and Improvements	101,878,000
Costs Capitalized Subsequent to Acquisition	21,116,000
Gross Amount at Which Carried at Close of Period, Land	12,843,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	127,806,000
Total	140,649,000
Accumulated Depreciation	54,391,000
Office [Member] | Harborside Plaza 4A [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2000
Acquired	2000
Initial Costs, Land	1,244,000
Initial Costs, Building and Improvements	56,144,000
Costs Capitalized Subsequent to Acquisition	14,698,000
Gross Amount at Which Carried at Close of Period, Land	1,244,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	70,842,000
Total	72,086,000
Accumulated Depreciation	28,181,000
Office [Member] | Harborside Plaza 5 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2002
Acquired	2002
Related Encumbrances	221,563,000
Initial Costs, Land	6,218,000
Initial Costs, Building and Improvements	170,682,000
Costs Capitalized Subsequent to Acquisition	52,013,000
Gross Amount at Which Carried at Close of Period, Land	5,705,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	223,208,000
Total	228,913,000
Accumulated Depreciation	80,254,000
Office [Member] | 101 Hudson Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1992
Acquired	2005
Initial Costs, Land	45,530,000
Initial Costs, Building and Improvements	271,376,000
Costs Capitalized Subsequent to Acquisition	921,000
Gross Amount at Which Carried at Close of Period, Land	45,530,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	272,297,000
Total	317,827,000
Accumulated Depreciation	68,400,000
Office [Member] | 3 AAA Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	2007
Initial Costs, Land	242,000
Initial Costs, Building and Improvements	3,218,000
Costs Capitalized Subsequent to Acquisition	1,598,000
Gross Amount at Which Carried at Close of Period, Land	242,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,816,000
Total	5,058,000
Accumulated Depreciation	1,438,000
Office [Member] | 700 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2007
Acquired	2007
Initial Costs, Land	490,000
Initial Costs, Building and Improvements	43,000
Costs Capitalized Subsequent to Acquisition	16,572,000
Gross Amount at Which Carried at Close of Period, Land	865,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	16,240,000
Total	17,105,000
Accumulated Depreciation	3,519,000
Office [Member] | 2 South Gold Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1974
Acquired	2007
Initial Costs, Land	476,000
Initial Costs, Building and Improvements	3,487,000
Costs Capitalized Subsequent to Acquisition	839,000
Gross Amount at Which Carried at Close of Period, Land	476,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,326,000
Total	4,802,000
Accumulated Depreciation	813,000
Office [Member] | 103 Carnegie Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	1996
Initial Costs, Land	2,566,000
Initial Costs, Building and Improvements	7,868,000
Costs Capitalized Subsequent to Acquisition	3,183,000
Gross Amount at Which Carried at Close of Period, Land	2,566,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	11,051,000
Total	13,617,000
Accumulated Depreciation	5,072,000
Office [Member] | 2 Independence Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	2009
Initial Costs, Land	1,300,000
Initial Costs, Building and Improvements	7,246,000
Costs Capitalized Subsequent to Acquisition	126,000
Gross Amount at Which Carried at Close of Period, Land	1,300,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,372,000
Total	8,672,000
Accumulated Depreciation	1,392,000
Office [Member] | 3 Independence Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	1997
Initial Costs, Land	1,997,000
Initial Costs, Building and Improvements	11,391,000
Costs Capitalized Subsequent to Acquisition	4,186,000
Gross Amount at Which Carried at Close of Period, Land	1,997,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	15,577,000
Total	17,574,000
Accumulated Depreciation	6,986,000
Office [Member] | 100 Overlook Center [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1997
Initial Costs, Land	2,378,000
Initial Costs, Building and Improvements	21,754,000
Costs Capitalized Subsequent to Acquisition	3,384,000
Gross Amount at Which Carried at Close of Period, Land	2,378,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	25,138,000
Total	27,516,000
Accumulated Depreciation	10,295,000
Office [Member] | 5 Vaughn Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1995
Initial Costs, Land	657,000
Initial Costs, Building and Improvements	9,800,000
Costs Capitalized Subsequent to Acquisition	3,001,000
Gross Amount at Which Carried at Close of Period, Land	657,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	12,801,000
Total	13,458,000
Accumulated Depreciation	6,434,000
Office [Member] | 377 Summerhill Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1977
Acquired	1997
Initial Costs, Land	649,000
Initial Costs, Building and Improvements	2,594,000
Costs Capitalized Subsequent to Acquisition	412,000
Gross Amount at Which Carried at Close of Period, Land	649,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,006,000
Total	3,655,000
Accumulated Depreciation	1,355,000
Office [Member] | 343 Thornall Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	2006
Initial Costs, Land	6,027,000
Initial Costs, Building and Improvements	39,101,000
Costs Capitalized Subsequent to Acquisition	3,302,000
Gross Amount at Which Carried at Close of Period, Land	6,027,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	42,403,000
Total	48,430,000
Accumulated Depreciation	10,907,000
Office [Member] | 500 College Road East [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984	[3]
Acquired	1998	[3]
Initial Costs, Land	614,000	[3]
Initial Costs, Building and Improvements	20,626,000	[3]
Costs Capitalized Subsequent to Acquisition	6,178,000	[3]
Gross Amount at Which Carried at Close of Period, Land	614,000	[3]
Gross Amount at Which Carried at Close of Period, Building and Improvements	26,804,000	[3]
Total	27,418,000	[3]
Accumulated Depreciation	11,800,000	[3]
Office [Member] | 581 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	1997
Initial Costs, Land	3,237,000
Initial Costs, Building and Improvements	12,949,000
Costs Capitalized Subsequent to Acquisition	26,205,000
Gross Amount at Which Carried at Close of Period, Land	8,115,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	34,276,000
Total	42,391,000
Accumulated Depreciation	15,447,000
Office [Member] | 2 Paragon Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	2005
Initial Costs, Land	999,000
Initial Costs, Building and Improvements	4,619,000
Costs Capitalized Subsequent to Acquisition	876,000
Gross Amount at Which Carried at Close of Period, Land	999,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,495,000
Total	6,494,000
Accumulated Depreciation	1,567,000
Office [Member] | 3 Paragon Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	2005
Initial Costs, Land	1,423,000
Initial Costs, Building and Improvements	6,041,000
Costs Capitalized Subsequent to Acquisition	1,550,000
Gross Amount at Which Carried at Close of Period, Land	1,423,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,591,000
Total	9,014,000
Accumulated Depreciation	2,235,000
Office [Member] | 4 Paragon Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2002
Acquired	2005
Initial Costs, Land	1,961,000
Initial Costs, Building and Improvements	8,827,000
Costs Capitalized Subsequent to Acquisition	-512,000
Gross Amount at Which Carried at Close of Period, Land	1,961,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,315,000
Total	10,276,000
Accumulated Depreciation	1,958,000
Office [Member] | 100 Willow Brook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	2005
Initial Costs, Land	1,264,000
Initial Costs, Building and Improvements	5,573,000
Costs Capitalized Subsequent to Acquisition	804,000
Gross Amount at Which Carried at Close of Period, Land	1,264,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,377,000
Total	7,641,000
Accumulated Depreciation	1,844,000
Office [Member] | 23 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1977
Acquired	2005
Related Encumbrances	29,210,000
Initial Costs, Land	4,336,000
Initial Costs, Building and Improvements	19,544,000
Costs Capitalized Subsequent to Acquisition	9,133,000
Gross Amount at Which Carried at Close of Period, Land	4,336,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	28,677,000
Total	33,013,000
Accumulated Depreciation	11,514,000
Office [Member] | One River Center, Building 1 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2004
Related Encumbrances	10,879,000
Initial Costs, Land	3,070,000
Initial Costs, Building and Improvements	17,414,000
Costs Capitalized Subsequent to Acquisition	3,881,000
Gross Amount at Which Carried at Close of Period, Land	2,451,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	21,914,000
Total	24,365,000
Accumulated Depreciation	7,051,000
Office [Member] | One River Center, Building 2 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2004
Related Encumbrances	12,204,000
Initial Costs, Land	2,468,000
Initial Costs, Building and Improvements	15,043,000
Costs Capitalized Subsequent to Acquisition	3,702,000
Gross Amount at Which Carried at Close of Period, Land	2,452,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	18,761,000
Total	21,213,000
Accumulated Depreciation	4,628,000
Office [Member] | One River Center, Building 3 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	2004
Related Encumbrances	19,393,000
Initial Costs, Land	4,051,000
Initial Costs, Building and Improvements	24,790,000
Costs Capitalized Subsequent to Acquisition	6,030,000
Gross Amount at Which Carried at Close of Period, Land	4,627,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	30,244,000
Total	34,871,000
Accumulated Depreciation	8,503,000
Office [Member] | 3600 Route 66 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1995
Initial Costs, Land	1,098,000
Initial Costs, Building and Improvements	18,146,000
Costs Capitalized Subsequent to Acquisition	10,455,000
Gross Amount at Which Carried at Close of Period, Land	1,098,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	28,601,000
Total	29,699,000
Accumulated Depreciation	10,121,000
Office [Member] | 1305 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1995
Initial Costs, Land	335,000
Initial Costs, Building and Improvements	2,560,000
Costs Capitalized Subsequent to Acquisition	648,000
Gross Amount at Which Carried at Close of Period, Land	291,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,252,000
Total	3,543,000
Accumulated Depreciation	1,463,000
Office [Member] | 1350 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1995
Initial Costs, Land	454,000
Initial Costs, Building and Improvements	7,134,000
Costs Capitalized Subsequent to Acquisition	823,000
Gross Amount at Which Carried at Close of Period, Land	454,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,957,000
Total	8,411,000
Accumulated Depreciation	3,805,000
Office [Member] | 325 Columbia Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1994
Initial Costs, Land	1,564,000
Costs Capitalized Subsequent to Acquisition	17,390,000
Gross Amount at Which Carried at Close of Period, Land	1,564,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	17,390,000	[1]
Total	18,954,000
Accumulated Depreciation	10,299,000	[2]
Office [Member] | 250 Johnson Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1977
Acquired	1997
Initial Costs, Land	2,004,000
Initial Costs, Building and Improvements	8,016,000
Costs Capitalized Subsequent to Acquisition	-4,825,000
Gross Amount at Which Carried at Close of Period, Land	930,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,265,000	[1]
Total	5,195,000
Accumulated Depreciation	1,618,000	[2]
Office [Member] | 201 Littleton Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1979
Acquired	1997
Initial Costs, Land	2,407,000
Initial Costs, Building and Improvements	9,627,000
Costs Capitalized Subsequent to Acquisition	3,505,000
Gross Amount at Which Carried at Close of Period, Land	2,407,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	13,132,000	[1]
Total	15,539,000
Accumulated Depreciation	5,265,000	[2]
Office [Member] | 4 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2001
Initial Costs, Land	5,213,000
Initial Costs, Building and Improvements	20,984,000
Costs Capitalized Subsequent to Acquisition	3,389,000
Gross Amount at Which Carried at Close of Period, Land	5,213,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	24,373,000	[1]
Total	29,586,000
Accumulated Depreciation	8,918,000	[2]
Office [Member] | 6 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2001
Initial Costs, Land	4,411,000
Initial Costs, Building and Improvements	17,796,000
Costs Capitalized Subsequent to Acquisition	3,287,000
Gross Amount at Which Carried at Close of Period, Land	4,411,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	21,083,000	[1]
Total	25,494,000
Accumulated Depreciation	7,867,000	[2]
Office [Member] | 7 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Acquired	1998
Initial Costs, Land	1,932,000
Initial Costs, Building and Improvements	27,788,000
Costs Capitalized Subsequent to Acquisition	6,310,000
Gross Amount at Which Carried at Close of Period, Land	1,932,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	34,098,000	[1]
Total	36,030,000
Accumulated Depreciation	14,566,000	[2]
Office [Member] | 8 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1998
Initial Costs, Land	1,865,000
Initial Costs, Building and Improvements	35,456,000
Costs Capitalized Subsequent to Acquisition	4,789,000
Gross Amount at Which Carried at Close of Period, Land	1,865,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	40,245,000	[1]
Total	42,110,000
Accumulated Depreciation	15,971,000	[2]
Office [Member] | 9 Campus Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2001
Initial Costs, Land	3,277,000
Initial Costs, Building and Improvements	11,796,000
Costs Capitalized Subsequent to Acquisition	16,318,000
Gross Amount at Which Carried at Close of Period, Land	5,842,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	25,549,000	[1]
Total	31,391,000
Accumulated Depreciation	9,647,000	[2]
Office [Member] | 4 Century Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	2004
Initial Costs, Land	1,787,000
Initial Costs, Building and Improvements	9,575,000
Costs Capitalized Subsequent to Acquisition	1,862,000
Gross Amount at Which Carried at Close of Period, Land	1,787,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	11,437,000	[1]
Total	13,224,000
Accumulated Depreciation	3,461,000	[2]
Office [Member] | 5 Century Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	2004
Initial Costs, Land	1,762,000
Initial Costs, Building and Improvements	9,341,000
Costs Capitalized Subsequent to Acquisition	2,390,000
Gross Amount at Which Carried at Close of Period, Land	1,762,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	11,731,000	[1]
Total	13,493,000
Accumulated Depreciation	3,616,000	[2]
Office [Member] | 6 Century Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	2004
Initial Costs, Land	1,289,000
Initial Costs, Building and Improvements	6,848,000
Costs Capitalized Subsequent to Acquisition	2,178,000
Gross Amount at Which Carried at Close of Period, Land	1,289,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,026,000	[1]
Total	10,315,000
Accumulated Depreciation	2,855,000	[2]
Office [Member] | 2 Dryden Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1998
Initial Costs, Land	778,000
Initial Costs, Building and Improvements	420,000
Costs Capitalized Subsequent to Acquisition	110,000
Gross Amount at Which Carried at Close of Period, Land	778,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	530,000	[1]
Total	1,308,000
Accumulated Depreciation	245,000	[2]
Office [Member] | 4 Gatehall Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	2000
Initial Costs, Land	8,452,000
Initial Costs, Building and Improvements	33,929,000
Costs Capitalized Subsequent to Acquisition	4,433,000
Gross Amount at Which Carried at Close of Period, Land	8,452,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	38,362,000	[1]
Total	46,814,000
Accumulated Depreciation	14,754,000	[2]
Office [Member] | 2 Hilton Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	1998
Initial Costs, Land	1,971,000
Initial Costs, Building and Improvements	32,007,000
Costs Capitalized Subsequent to Acquisition	4,958,000
Gross Amount at Which Carried at Close of Period, Land	1,971,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	36,965,000	[1]
Total	38,936,000
Accumulated Depreciation	16,047,000	[2]
Office [Member] | 1633 Littleton Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1978
Acquired	2002
Initial Costs, Land	2,283,000
Initial Costs, Building and Improvements	9,550,000
Costs Capitalized Subsequent to Acquisition	163,000
Gross Amount at Which Carried at Close of Period, Land	2,355,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,641,000	[1]
Total	11,996,000
Accumulated Depreciation	4,227,000	[2]
Office [Member] | 600 Parsippany Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1978
Acquired	1994
Initial Costs, Land	1,257,000
Initial Costs, Building and Improvements	5,594,000
Costs Capitalized Subsequent to Acquisition	3,277,000
Gross Amount at Which Carried at Close of Period, Land	1,257,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,871,000	[1]
Total	10,128,000
Accumulated Depreciation	4,515,000	[2]
Office [Member] | 1 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1998
Initial Costs, Land	1,689,000
Initial Costs, Building and Improvements	24,699,000
Costs Capitalized Subsequent to Acquisition	2,826,000
Gross Amount at Which Carried at Close of Period, Land	1,021,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	28,193,000	[1]
Total	29,214,000
Accumulated Depreciation	12,489,000	[2]
Office [Member] | 4 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	2009
Related Encumbrances	14,575,000
Initial Costs, Land	2,400,000
Initial Costs, Building and Improvements	13,486,000
Costs Capitalized Subsequent to Acquisition	-8,399,000
Gross Amount at Which Carried at Close of Period, Land	1,131,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,356,000	[1]
Total	7,487,000
Accumulated Depreciation	1,149,000	[2]
Office [Member] | 5 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1998
Initial Costs, Land	1,160,000
Initial Costs, Building and Improvements	25,214,000
Costs Capitalized Subsequent to Acquisition	2,723,000
Gross Amount at Which Carried at Close of Period, Land	1,161,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	27,936,000	[1]
Total	29,097,000
Accumulated Depreciation	11,307,000	[2]
Office [Member] | 7 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1998
Initial Costs, Land	2,084,000
Initial Costs, Building and Improvements	26,083,000
Costs Capitalized Subsequent to Acquisition	841,000
Gross Amount at Which Carried at Close of Period, Land	2,084,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	26,924,000	[1]
Total	29,008,000
Accumulated Depreciation	11,063,000	[2]
Office [Member] | 14 Sylvan Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2013
Acquired	2013
Initial Costs, Land	13,049,000
Initial Costs, Building and Improvements	26,841,000
Costs Capitalized Subsequent to Acquisition	8,540,000
Gross Amount at Which Carried at Close of Period, Land	13,049,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	35,381,000	[1]
Total	48,430,000
Accumulated Depreciation	1,841,000	[2]
Office [Member] | 20 Waterview Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	2009
Related Encumbrances	24,678,000
Initial Costs, Land	4,500,000
Initial Costs, Building and Improvements	27,246,000
Costs Capitalized Subsequent to Acquisition	-1,233,000
Gross Amount at Which Carried at Close of Period, Land	4,208,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	26,305,000	[1]
Total	30,513,000
Accumulated Depreciation	4,736,000	[2]
Office [Member] | 35 Waterview Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	2006
Initial Costs, Land	5,133,000
Initial Costs, Building and Improvements	28,059,000
Costs Capitalized Subsequent to Acquisition	887,000
Gross Amount at Which Carried at Close of Period, Land	5,133,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	28,946,000	[1]
Total	34,079,000
Accumulated Depreciation	7,304,000	[2]
Office [Member] | 5 Wood Hollow Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1979
Acquired	2004
Initial Costs, Land	5,302,000
Initial Costs, Building and Improvements	26,488,000
Costs Capitalized Subsequent to Acquisition	16,441,000
Gross Amount at Which Carried at Close of Period, Land	5,302,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	42,929,000	[1]
Total	48,231,000
Accumulated Depreciation	15,710,000	[2]
Office [Member] | 999 Riverview Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1995
Initial Costs, Land	476,000
Initial Costs, Building and Improvements	6,024,000
Costs Capitalized Subsequent to Acquisition	2,793,000
Gross Amount at Which Carried at Close of Period, Land	1,102,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,191,000	[1]
Total	9,293,000
Accumulated Depreciation	4,018,000	[2]
Office [Member] | 222 Mt. Airy Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1996
Initial Costs, Land	775,000
Initial Costs, Building and Improvements	3,636,000
Costs Capitalized Subsequent to Acquisition	2,278,000
Gross Amount at Which Carried at Close of Period, Land	775,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,914,000
Total	6,689,000
Accumulated Depreciation	2,662,000
Office [Member] | 233 Mt. Airy Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1996
Initial Costs, Land	1,034,000
Initial Costs, Building and Improvements	5,033,000
Costs Capitalized Subsequent to Acquisition	2,204,000
Gross Amount at Which Carried at Close of Period, Land	1,034,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,237,000
Total	8,271,000
Accumulated Depreciation	2,737,000
Office [Member] | 440 Route 22 East [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	2010
Initial Costs, Land	3,986,000
Initial Costs, Building and Improvements	13,658,000
Costs Capitalized Subsequent to Acquisition	4,814,000
Gross Amount at Which Carried at Close of Period, Land	3,986,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	18,472,000
Total	22,458,000
Accumulated Depreciation	3,661,000
Office [Member] | 721 Route 202/206 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1997
Initial Costs, Land	6,730,000
Initial Costs, Building and Improvements	26,919,000
Costs Capitalized Subsequent to Acquisition	9,711,000
Gross Amount at Which Carried at Close of Period, Land	6,730,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	36,630,000
Total	43,360,000
Accumulated Depreciation	18,700,000
Office [Member] | 10 Independence Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	2009
Related Encumbrances	16,924,000
Initial Costs, Land	2,300,000
Initial Costs, Building and Improvements	15,499,000
Costs Capitalized Subsequent to Acquisition	-6,031,000
Gross Amount at Which Carried at Close of Period, Land	1,482,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	10,286,000
Total	11,768,000
Accumulated Depreciation	1,573,000
Office [Member] | 100 Walnut Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1994
Related Encumbrances	18,542,000
Costs Capitalized Subsequent to Acquisition	17,640,000
Gross Amount at Which Carried at Close of Period, Land	1,822,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	15,818,000
Total	17,640,000
Accumulated Depreciation	10,340,000
Office [Member] | 6 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1973
Acquired	1994
Initial Costs, Land	250,000
Costs Capitalized Subsequent to Acquisition	1,784,000
Gross Amount at Which Carried at Close of Period, Land	250,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,784,000
Total	2,034,000
Accumulated Depreciation	712,000
Office [Member] | 11 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1981
Acquired	1994
Initial Costs, Land	470,000
Costs Capitalized Subsequent to Acquisition	5,556,000
Gross Amount at Which Carried at Close of Period, Land	470,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,556,000
Total	6,026,000
Accumulated Depreciation	4,655,000
Office [Member] | 12 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1967
Acquired	1997
Initial Costs, Land	887,000
Initial Costs, Building and Improvements	3,549,000
Costs Capitalized Subsequent to Acquisition	1,543,000
Gross Amount at Which Carried at Close of Period, Land	887,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,092,000
Total	5,979,000
Accumulated Depreciation	2,354,000
Office [Member] | 14 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1971
Acquired	2003
Initial Costs, Land	1,283,000
Initial Costs, Building and Improvements	6,344,000
Costs Capitalized Subsequent to Acquisition	1,043,000
Gross Amount at Which Carried at Close of Period, Land	1,283,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,387,000
Total	8,670,000
Accumulated Depreciation	2,185,000
Office [Member] | 20 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1994
Initial Costs, Land	2,346,000
Costs Capitalized Subsequent to Acquisition	21,447,000
Gross Amount at Which Carried at Close of Period, Land	2,346,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	21,447,000
Total	23,793,000
Accumulated Depreciation	11,154,000
Office [Member] | 25 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1971
Acquired	2002
Initial Costs, Land	1,520,000
Initial Costs, Building and Improvements	6,186,000
Costs Capitalized Subsequent to Acquisition	1,028,000
Gross Amount at Which Carried at Close of Period, Land	1,520,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,214,000
Total	8,734,000
Accumulated Depreciation	3,132,000
Office [Member] | 65 Jackson Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	1994
Initial Costs, Land	541,000
Costs Capitalized Subsequent to Acquisition	6,223,000
Gross Amount at Which Carried at Close of Period, Land	542,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,222,000
Total	6,764,000
Accumulated Depreciation	4,100,000
Office [Member] | 890 Mountain Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1977
Acquired	1997
Initial Costs, Land	2,796,000
Initial Costs, Building and Improvements	11,185,000
Costs Capitalized Subsequent to Acquisition	6,167,000
Gross Amount at Which Carried at Close of Period, Land	3,765,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	16,383,000
Total	20,148,000
Accumulated Depreciation	6,843,000
Office [Member] | 125 Broad Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1970
Acquired	2007
Initial Costs, Land	50,191,000
Initial Costs, Building and Improvements	207,002,000
Costs Capitalized Subsequent to Acquisition	48,289,000
Gross Amount at Which Carried at Close of Period, Land	50,191,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	255,291,000
Total	305,482,000
Accumulated Depreciation	48,103,000
Office [Member] | 100 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1975
Acquired	1997
Initial Costs, Land	220,000
Initial Costs, Building and Improvements	5,366,000
Costs Capitalized Subsequent to Acquisition	1,653,000
Gross Amount at Which Carried at Close of Period, Land	220,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,019,000
Total	7,239,000
Accumulated Depreciation	3,117,000
Office [Member] | 101 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1971
Acquired	1997
Initial Costs, Land	267,000
Initial Costs, Building and Improvements	5,838,000
Costs Capitalized Subsequent to Acquisition	-3,536,000
Gross Amount at Which Carried at Close of Period, Land	101,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,468,000
Total	2,569,000
Accumulated Depreciation	1,060,000
Office [Member] | 1 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Acquired	1997
Initial Costs, Land	66,000
Initial Costs, Building and Improvements	1,711,000
Costs Capitalized Subsequent to Acquisition	210,000
Gross Amount at Which Carried at Close of Period, Land	66,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,921,000	[1]
Total	1,987,000
Accumulated Depreciation	890,000	[2]
Office [Member] | 2 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1997
Initial Costs, Land	109,000
Initial Costs, Building and Improvements	3,128,000
Costs Capitalized Subsequent to Acquisition	1,474,000
Gross Amount at Which Carried at Close of Period, Land	109,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,602,000	[1]
Total	4,711,000
Accumulated Depreciation	2,057,000	[2]
Office [Member] | 7 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1998
Initial Costs, Land	330,000
Initial Costs, Building and Improvements	13,013,000
Costs Capitalized Subsequent to Acquisition	3,172,000
Gross Amount at Which Carried at Close of Period, Land	330,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	16,185,000	[1]
Total	16,515,000
Accumulated Depreciation	6,868,000	[2]
Office [Member] | 17 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989	[3]
Acquired	1997	[3]
Initial Costs, Building and Improvements	7,269,000	[3]
Costs Capitalized Subsequent to Acquisition	1,484,000	[3]
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,753,000	[1],[3]
Total	8,753,000	[3]
Accumulated Depreciation	3,725,000	[2],[3]
Office [Member] | 1 Barker Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1975
Acquired	1997
Initial Costs, Land	208,000
Initial Costs, Building and Improvements	9,629,000
Costs Capitalized Subsequent to Acquisition	2,546,000
Gross Amount at Which Carried at Close of Period, Land	207,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	12,176,000	[1]
Total	12,383,000
Accumulated Depreciation	5,083,000	[2]
Office [Member] | 3 Barker Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	1997
Initial Costs, Land	122,000
Initial Costs, Building and Improvements	7,864,000
Costs Capitalized Subsequent to Acquisition	1,781,000
Gross Amount at Which Carried at Close of Period, Land	122,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,645,000	[1]
Total	9,767,000
Accumulated Depreciation	4,128,000	[2]
Office [Member] | 50 Main Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1997
Initial Costs, Land	564,000
Initial Costs, Building and Improvements	48,105,000
Costs Capitalized Subsequent to Acquisition	14,371,000
Gross Amount at Which Carried at Close of Period, Land	564,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	62,476,000	[1]
Total	63,040,000
Accumulated Depreciation	27,557,000	[2]
Office [Member] | 11 Martine Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1997
Initial Costs, Land	127,000
Initial Costs, Building and Improvements	26,833,000
Costs Capitalized Subsequent to Acquisition	9,209,000
Gross Amount at Which Carried at Close of Period, Land	127,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	36,042,000	[1]
Total	36,169,000
Accumulated Depreciation	16,385,000	[2]
Office [Member] | 1 Water Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1979
Acquired	1997
Initial Costs, Land	211,000
Initial Costs, Building and Improvements	5,382,000
Costs Capitalized Subsequent to Acquisition	1,101,000
Gross Amount at Which Carried at Close of Period, Land	211,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,483,000	[1]
Total	6,694,000
Accumulated Depreciation	2,835,000	[2]
Office [Member] | 1 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Acquired	1997
Initial Costs, Land	1,104,000
Initial Costs, Building and Improvements	11,904,000
Costs Capitalized Subsequent to Acquisition	3,281,000
Gross Amount at Which Carried at Close of Period, Land	1,105,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	15,184,000	[1]
Total	16,289,000
Accumulated Depreciation	6,592,000	[2]
Office [Member] | 3 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1997
Initial Costs, Land	385,000
Initial Costs, Building and Improvements	6,256,000
Costs Capitalized Subsequent to Acquisition	2,103,000
Gross Amount at Which Carried at Close of Period, Land	385,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,359,000
Total	8,744,000
Accumulated Depreciation	3,657,000
Office [Member] | 3 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	2003
Initial Costs, Land	1,322,000
Initial Costs, Building and Improvements	4,777,000
Costs Capitalized Subsequent to Acquisition	2,321,000
Gross Amount at Which Carried at Close of Period, Land	1,322,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,098,000
Total	8,420,000
Accumulated Depreciation	3,019,000
Office [Member] | 1201 Connecticut Avenue, NW [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1940
Acquired	1999
Initial Costs, Land	14,228,000
Initial Costs, Building and Improvements	18,571,000
Costs Capitalized Subsequent to Acquisition	5,846,000
Gross Amount at Which Carried at Close of Period, Land	14,228,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	24,417,000
Total	38,645,000
Accumulated Depreciation	10,322,000
Office [Member] | 1400 L Street, NW [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1998
Initial Costs, Land	13,054,000
Initial Costs, Building and Improvements	27,423,000
Costs Capitalized Subsequent to Acquisition	7,909,000
Gross Amount at Which Carried at Close of Period, Land	13,054,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	35,332,000
Total	48,386,000
Accumulated Depreciation	17,571,000
Office [Member] | 9200 Edmonston Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	2006
Related Encumbrances	3,951,000
Initial Costs, Land	1,547,000
Initial Costs, Building and Improvements	4,131,000
Costs Capitalized Subsequent to Acquisition	-2,484,000
Gross Amount at Which Carried at Close of Period, Land	610,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,584,000
Total	3,194,000
Accumulated Depreciation	1,336,000
Office [Member] | 6301 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	2006
Initial Costs, Land	5,168,000
Initial Costs, Building and Improvements	14,706,000
Costs Capitalized Subsequent to Acquisition	1,289,000
Gross Amount at Which Carried at Close of Period, Land	5,168,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	15,995,000
Total	21,163,000
Accumulated Depreciation	3,981,000
Office [Member] | 6303 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	2006
Initial Costs, Land	5,115,000
Initial Costs, Building and Improvements	13,860,000
Costs Capitalized Subsequent to Acquisition	770,000
Gross Amount at Which Carried at Close of Period, Land	5,115,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	14,630,000
Total	19,745,000
Accumulated Depreciation	4,236,000
Office [Member] | 6305 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	2006
Initial Costs, Land	5,615,000
Initial Costs, Building and Improvements	14,420,000
Costs Capitalized Subsequent to Acquisition	1,071,000
Gross Amount at Which Carried at Close of Period, Land	5,615,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	15,491,000
Total	21,106,000
Accumulated Depreciation	3,835,000
Office [Member] | 6404 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	2006
Initial Costs, Land	7,578,000
Initial Costs, Building and Improvements	20,785,000
Costs Capitalized Subsequent to Acquisition	1,998,000
Gross Amount at Which Carried at Close of Period, Land	7,578,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	22,783,000
Total	30,361,000
Accumulated Depreciation	6,684,000
Office [Member] | 6406 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	2006
Initial Costs, Land	7,514,000
Initial Costs, Building and Improvements	21,152,000
Costs Capitalized Subsequent to Acquisition	5,770,000
Gross Amount at Which Carried at Close of Period, Land	7,514,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	26,922,000
Total	34,436,000
Accumulated Depreciation	5,119,000
Office [Member] | 6411 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	2006
Initial Costs, Land	6,867,000
Initial Costs, Building and Improvements	17,470,000
Costs Capitalized Subsequent to Acquisition	965,000
Gross Amount at Which Carried at Close of Period, Land	6,867,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	18,435,000
Total	25,302,000
Accumulated Depreciation	4,789,000
Office [Member] | 4200 Parliament Place [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1998
Initial Costs, Land	2,114,000
Initial Costs, Building and Improvements	13,546,000
Costs Capitalized Subsequent to Acquisition	1,227,000
Gross Amount at Which Carried at Close of Period, Land	1,393,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	15,494,000
Total	16,887,000
Accumulated Depreciation	7,227,000
Office And Office/Flex Buildings [Member] | 3 Terri Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	1998
Initial Costs, Land	652,000
Initial Costs, Building and Improvements	3,433,000
Costs Capitalized Subsequent to Acquisition	1,537,000
Gross Amount at Which Carried at Close of Period, Land	658,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,964,000	[1]
Total	5,622,000
Accumulated Depreciation	2,110,000	[2]
Office And Office/Flex Buildings [Member] | 5 Terri Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1992
Acquired	1998
Initial Costs, Land	564,000
Initial Costs, Building and Improvements	3,792,000
Costs Capitalized Subsequent to Acquisition	2,444,000
Gross Amount at Which Carried at Close of Period, Land	569,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,231,000	[1]
Total	6,800,000
Accumulated Depreciation	2,784,000	[2]
Office And Office/Flex Buildings [Member] | 2 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1999
Initial Costs, Land	723,000
Initial Costs, Building and Improvements	2,893,000
Costs Capitalized Subsequent to Acquisition	544,000
Gross Amount at Which Carried at Close of Period, Land	723,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,437,000	[1]
Total	4,160,000
Accumulated Depreciation	1,351,000	[2]
Office And Office/Flex Buildings [Member] | 101 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1998
Initial Costs, Land	422,000
Initial Costs, Building and Improvements	3,528,000
Costs Capitalized Subsequent to Acquisition	436,000
Gross Amount at Which Carried at Close of Period, Land	426,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,960,000	[1]
Total	4,386,000
Accumulated Depreciation	1,782,000	[2]
Office And Office/Flex Buildings [Member] | 102 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1999
Initial Costs, Land	389,000
Initial Costs, Building and Improvements	1,554,000
Costs Capitalized Subsequent to Acquisition	556,000
Gross Amount at Which Carried at Close of Period, Land	389,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,110,000	[1]
Total	2,499,000
Accumulated Depreciation	750,000	[2]
Office And Office/Flex Buildings [Member] | 201 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1998
Initial Costs, Land	254,000
Initial Costs, Building and Improvements	1,694,000
Costs Capitalized Subsequent to Acquisition	329,000
Gross Amount at Which Carried at Close of Period, Land	258,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,019,000	[1]
Total	2,277,000
Accumulated Depreciation	850,000	[2]
Office And Office/Flex Buildings [Member] | 202 Commerce Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1999
Initial Costs, Land	490,000
Initial Costs, Building and Improvements	1,963,000
Costs Capitalized Subsequent to Acquisition	384,000
Gross Amount at Which Carried at Close of Period, Land	490,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,347,000	[1]
Total	2,837,000
Accumulated Depreciation	851,000	[2]
Office And Office/Flex Buildings [Member] | 1 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1998
Initial Costs, Land	226,000
Initial Costs, Building and Improvements	1,453,000
Costs Capitalized Subsequent to Acquisition	739,000
Gross Amount at Which Carried at Close of Period, Land	228,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,190,000	[1]
Total	2,418,000
Accumulated Depreciation	873,000	[2]
Office And Office/Flex Buildings [Member] | 2 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	2000
Initial Costs, Land	801,000
Initial Costs, Building and Improvements	3,206,000
Costs Capitalized Subsequent to Acquisition	707,000
Gross Amount at Which Carried at Close of Period, Land	801,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,913,000	[1]
Total	4,714,000
Accumulated Depreciation	1,360,000	[2]
Office And Office/Flex Buildings [Member] | 101 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1998
Initial Costs, Land	241,000
Initial Costs, Building and Improvements	2,262,000
Costs Capitalized Subsequent to Acquisition	807,000
Gross Amount at Which Carried at Close of Period, Land	244,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,066,000	[1]
Total	3,310,000
Accumulated Depreciation	1,332,000	[2]
Office And Office/Flex Buildings [Member] | 102 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1998
Initial Costs, Land	353,000
Initial Costs, Building and Improvements	3,607,000
Costs Capitalized Subsequent to Acquisition	420,000
Gross Amount at Which Carried at Close of Period, Land	357,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,023,000	[1]
Total	4,380,000
Accumulated Depreciation	1,701,000	[2]
Office And Office/Flex Buildings [Member] | 225 Executive Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1998
Initial Costs, Land	323,000
Initial Costs, Building and Improvements	2,477,000
Costs Capitalized Subsequent to Acquisition	693,000
Gross Amount at Which Carried at Close of Period, Land	326,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,167,000	[1]
Total	3,493,000
Accumulated Depreciation	1,436,000	[2]
Office And Office/Flex Buildings [Member] | 97 Foster Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Acquired	1998
Initial Costs, Land	208,000
Initial Costs, Building and Improvements	1,382,000
Costs Capitalized Subsequent to Acquisition	389,000
Gross Amount at Which Carried at Close of Period, Land	211,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,768,000	[1]
Total	1,979,000
Accumulated Depreciation	823,000	[2]
Office And Office/Flex Buildings [Member] | 1507 Lancer Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Acquired	1998
Initial Costs, Land	119,000
Initial Costs, Building and Improvements	1,106,000
Costs Capitalized Subsequent to Acquisition	209,000
Gross Amount at Which Carried at Close of Period, Land	120,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,314,000	[1]
Total	1,434,000
Accumulated Depreciation	561,000	[2]
Office And Office/Flex Buildings [Member] | 1245 North Church Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	2001
Initial Costs, Land	691,000
Initial Costs, Building and Improvements	2,810,000
Costs Capitalized Subsequent to Acquisition	83,000
Gross Amount at Which Carried at Close of Period, Land	691,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,893,000	[1]
Total	3,584,000
Accumulated Depreciation	997,000	[2]
Office And Office/Flex Buildings [Member] | 1247 North Church Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	2001
Initial Costs, Land	805,000
Initial Costs, Building and Improvements	3,269,000
Costs Capitalized Subsequent to Acquisition	117,000
Gross Amount at Which Carried at Close of Period, Land	805,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,386,000	[1]
Total	4,191,000
Accumulated Depreciation	1,172,000	[2]
Office And Office/Flex Buildings [Member] | 1256 North Church Street [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	1998
Initial Costs, Land	354,000
Initial Costs, Building and Improvements	3,098,000
Costs Capitalized Subsequent to Acquisition	658,000
Gross Amount at Which Carried at Close of Period, Land	357,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,753,000
Total	4,110,000
Accumulated Depreciation	1,542,000
Office And Office/Flex Buildings [Member] | 840 North Lenola Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Acquired	1998
Initial Costs, Land	329,000
Initial Costs, Building and Improvements	2,366,000
Costs Capitalized Subsequent to Acquisition	246,000
Gross Amount at Which Carried at Close of Period, Land	333,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,608,000
Total	2,941,000
Accumulated Depreciation	1,206,000
Office And Office/Flex Buildings [Member] | 844 North Lenola Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Acquired	1998
Initial Costs, Land	239,000
Initial Costs, Building and Improvements	1,714,000
Costs Capitalized Subsequent to Acquisition	298,000
Gross Amount at Which Carried at Close of Period, Land	241,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,010,000
Total	2,251,000
Accumulated Depreciation	881,000
Office And Office/Flex Buildings [Member] | 915 North Lenola Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	2000
Initial Costs, Land	508,000
Initial Costs, Building and Improvements	2,034,000
Costs Capitalized Subsequent to Acquisition	273,000
Gross Amount at Which Carried at Close of Period, Land	508,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,307,000
Total	2,815,000
Accumulated Depreciation	980,000
Office And Office/Flex Buildings [Member] | 2 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2000
Acquired	2001
Initial Costs, Land	701,000
Initial Costs, Building and Improvements	2,807,000
Costs Capitalized Subsequent to Acquisition	64,000
Gross Amount at Which Carried at Close of Period, Land	701,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,871,000
Total	3,572,000
Accumulated Depreciation	992,000
Office And Office/Flex Buildings [Member] | 30 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1997
Acquired	1998
Initial Costs, Land	234,000
Initial Costs, Building and Improvements	1,954,000
Costs Capitalized Subsequent to Acquisition	408,000
Gross Amount at Which Carried at Close of Period, Land	236,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,360,000
Total	2,596,000
Accumulated Depreciation	1,156,000
Office And Office/Flex Buildings [Member] | 31 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	2001
Initial Costs, Land	815,000
Initial Costs, Building and Improvements	3,276,000
Costs Capitalized Subsequent to Acquisition	145,000
Gross Amount at Which Carried at Close of Period, Land	815,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,421,000
Total	4,236,000
Accumulated Depreciation	1,211,000
Office And Office/Flex Buildings [Member] | 40 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1996
Acquired	1998
Initial Costs, Land	297,000
Initial Costs, Building and Improvements	2,393,000
Costs Capitalized Subsequent to Acquisition	220,000
Gross Amount at Which Carried at Close of Period, Land	301,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,609,000
Total	2,910,000
Accumulated Depreciation	1,156,000
Office And Office/Flex Buildings [Member] | 41 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	2001
Initial Costs, Land	605,000
Initial Costs, Building and Improvements	2,459,000
Costs Capitalized Subsequent to Acquisition	178,000
Gross Amount at Which Carried at Close of Period, Land	605,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,637,000
Total	3,242,000
Accumulated Depreciation	923,000
Office And Office/Flex Buildings [Member] | 50 Twosome Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1997
Acquired	1998
Initial Costs, Land	301,000
Initial Costs, Building and Improvements	2,330,000
Costs Capitalized Subsequent to Acquisition	98,000
Gross Amount at Which Carried at Close of Period, Land	304,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,425,000
Total	2,729,000
Accumulated Depreciation	1,065,000
Office And Office/Flex Buildings [Member] | 1451 Metropolitan Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1996
Acquired	1998
Initial Costs, Land	203,000
Initial Costs, Building and Improvements	1,189,000
Costs Capitalized Subsequent to Acquisition	74,000
Gross Amount at Which Carried at Close of Period, Land	206,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,260,000
Total	1,466,000
Accumulated Depreciation	534,000
Office And Office/Flex Buildings [Member] | 100 Horizon Center Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1995
Initial Costs, Land	205,000
Initial Costs, Building and Improvements	1,676,000
Costs Capitalized Subsequent to Acquisition	728,000
Gross Amount at Which Carried at Close of Period, Land	323,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,286,000
Total	2,609,000
Accumulated Depreciation	934,000
Office And Office/Flex Buildings [Member] | 200 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1991
Acquired	1995
Initial Costs, Land	205,000
Initial Costs, Building and Improvements	3,027,000
Costs Capitalized Subsequent to Acquisition	714,000
Gross Amount at Which Carried at Close of Period, Land	356,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,590,000
Total	3,946,000
Accumulated Depreciation	1,700,000
Office And Office/Flex Buildings [Member] | 300 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1995
Initial Costs, Land	379,000
Initial Costs, Building and Improvements	4,355,000
Costs Capitalized Subsequent to Acquisition	1,188,000
Gross Amount at Which Carried at Close of Period, Land	530,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,392,000
Total	5,922,000
Accumulated Depreciation	2,537,000
Office And Office/Flex Buildings [Member] | 500 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1995
Initial Costs, Land	379,000
Initial Costs, Building and Improvements	3,395,000
Costs Capitalized Subsequent to Acquisition	921,000
Gross Amount at Which Carried at Close of Period, Land	495,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,200,000
Total	4,695,000
Accumulated Depreciation	2,029,000
Office And Office/Flex Buildings [Member] | 600 Horizon Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2002
Acquired	2002
Initial Costs, Building and Improvements	7,549,000
Costs Capitalized Subsequent to Acquisition	651,000
Gross Amount at Which Carried at Close of Period, Land	685,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,515,000
Total	8,200,000
Accumulated Depreciation	2,270,000
Office And Office/Flex Buildings [Member] | 1325 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1995
Initial Costs, Land	270,000
Initial Costs, Building and Improvements	2,928,000
Costs Capitalized Subsequent to Acquisition	725,000
Gross Amount at Which Carried at Close of Period, Land	270,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,653,000
Total	3,923,000
Accumulated Depreciation	1,749,000
Office And Office/Flex Buildings [Member] | 1340 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1992
Acquired	1995
Initial Costs, Land	489,000
Initial Costs, Building and Improvements	4,621,000
Costs Capitalized Subsequent to Acquisition	1,817,000
Gross Amount at Which Carried at Close of Period, Land	489,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,438,000
Total	6,927,000
Accumulated Depreciation	3,169,000
Office And Office/Flex Buildings [Member] | 1345 Campus Parkway [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Acquired	1997
Initial Costs, Land	1,023,000
Initial Costs, Building and Improvements	5,703,000
Costs Capitalized Subsequent to Acquisition	1,703,000
Gross Amount at Which Carried at Close of Period, Land	1,024,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,405,000
Total	8,429,000
Accumulated Depreciation	3,526,000
Office And Office/Flex Buildings [Member] | 1433 Highway 34 [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1995
Initial Costs, Land	889,000
Initial Costs, Building and Improvements	4,321,000
Costs Capitalized Subsequent to Acquisition	1,617,000
Gross Amount at Which Carried at Close of Period, Land	889,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,938,000
Total	6,827,000
Accumulated Depreciation	2,670,000
Office And Office/Flex Buildings [Member] | 1320 Wyckoff Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1995
Initial Costs, Land	255,000
Initial Costs, Building and Improvements	1,285,000
Costs Capitalized Subsequent to Acquisition	291,000
Gross Amount at Which Carried at Close of Period, Land	216,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,615,000	[1]
Total	1,831,000
Accumulated Depreciation	833,000	[2]
Office And Office/Flex Buildings [Member] | 1324 Wyckoff Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1995
Initial Costs, Land	230,000
Initial Costs, Building and Improvements	1,439,000
Costs Capitalized Subsequent to Acquisition	284,000
Gross Amount at Which Carried at Close of Period, Land	190,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,763,000	[1]
Total	1,953,000
Accumulated Depreciation	777,000	[2]
Office And Office/Flex Buildings [Member] | 1 Center Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1999
Acquired	1999
Initial Costs, Land	270,000
Initial Costs, Building and Improvements	1,824,000
Costs Capitalized Subsequent to Acquisition	493,000
Gross Amount at Which Carried at Close of Period, Land	270,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,317,000	[1]
Total	2,587,000
Accumulated Depreciation	897,000	[2]
Office And Office/Flex Buildings [Member] | 2 Center Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	1998
Initial Costs, Land	191,000
Costs Capitalized Subsequent to Acquisition	2,646,000
Gross Amount at Which Carried at Close of Period, Land	191,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,646,000	[1]
Total	2,837,000
Accumulated Depreciation	1,037,000	[2]
Office And Office/Flex Buildings [Member] | 11 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1995
Initial Costs, Land	586,000
Initial Costs, Building and Improvements	2,986,000
Costs Capitalized Subsequent to Acquisition	1,000,000
Gross Amount at Which Carried at Close of Period, Land	586,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,986,000	[1]
Total	4,572,000
Accumulated Depreciation	1,879,000	[2]
Office And Office/Flex Buildings [Member] | 20 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1992
Acquired	1995
Initial Costs, Land	516,000
Initial Costs, Building and Improvements	3,108,000
Costs Capitalized Subsequent to Acquisition	111,000
Gross Amount at Which Carried at Close of Period, Land	516,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,219,000	[1]
Total	3,735,000
Accumulated Depreciation	1,514,000	[2]
Office And Office/Flex Buildings [Member] | 29 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1995
Initial Costs, Land	586,000
Initial Costs, Building and Improvements	3,092,000
Costs Capitalized Subsequent to Acquisition	858,000
Gross Amount at Which Carried at Close of Period, Land	586,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,950,000	[1]
Total	4,536,000
Accumulated Depreciation	1,642,000	[2]
Office And Office/Flex Buildings [Member] | 40 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1995
Initial Costs, Land	516,000
Initial Costs, Building and Improvements	3,260,000
Costs Capitalized Subsequent to Acquisition	1,510,000
Gross Amount at Which Carried at Close of Period, Land	516,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,770,000	[1]
Total	5,286,000
Accumulated Depreciation	2,058,000	[2]
Office And Office/Flex Buildings [Member] | 45 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1992
Acquired	1995
Initial Costs, Land	536,000
Initial Costs, Building and Improvements	3,379,000
Costs Capitalized Subsequent to Acquisition	576,000
Gross Amount at Which Carried at Close of Period, Land	536,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,955,000	[1]
Total	4,491,000
Accumulated Depreciation	2,023,000	[2]
Office And Office/Flex Buildings [Member] | 60 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1995
Initial Costs, Land	526,000
Initial Costs, Building and Improvements	3,257,000
Costs Capitalized Subsequent to Acquisition	635,000
Gross Amount at Which Carried at Close of Period, Land	526,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,892,000	[1]
Total	4,418,000
Accumulated Depreciation	2,027,000	[2]
Office And Office/Flex Buildings [Member] | 80 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1996
Acquired	1996
Initial Costs, Land	227,000
Costs Capitalized Subsequent to Acquisition	1,357,000
Gross Amount at Which Carried at Close of Period, Land	227,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,357,000	[1]
Total	1,584,000
Accumulated Depreciation	597,000	[2]
Office And Office/Flex Buildings [Member] | 100 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1996
Acquired	1996
Initial Costs, Land	226,000
Costs Capitalized Subsequent to Acquisition	1,356,000
Gross Amount at Which Carried at Close of Period, Land	226,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,356,000	[1]
Total	1,582,000
Accumulated Depreciation	596,000	[2]
Office And Office/Flex Buildings [Member] | 120 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1994
Acquired	1995
Initial Costs, Land	228,000
Costs Capitalized Subsequent to Acquisition	1,290,000
Gross Amount at Which Carried at Close of Period, Land	229,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,289,000	[1]
Total	1,518,000
Accumulated Depreciation	617,000	[2]
Office And Office/Flex Buildings [Member] | 140 Commerce Way [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1994
Acquired	1995
Initial Costs, Land	229,000
Costs Capitalized Subsequent to Acquisition	1,288,000
Gross Amount at Which Carried at Close of Period, Land	228,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,289,000	[1]
Total	1,517,000
Accumulated Depreciation	617,000	[2]
Office And Office/Flex Buildings [Member] | 11 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1974
Acquired	1997
Initial Costs, Land	149,000
Initial Costs, Building and Improvements	2,159,000
Costs Capitalized Subsequent to Acquisition	529,000
Gross Amount at Which Carried at Close of Period, Land	149,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,688,000
Total	2,837,000
Accumulated Depreciation	1,129,000
Office And Office/Flex Buildings [Member] | 75 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1997
Initial Costs, Land	2,314,000
Initial Costs, Building and Improvements	4,716,000
Costs Capitalized Subsequent to Acquisition	107,000
Gross Amount at Which Carried at Close of Period, Land	2,314,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,823,000
Total	7,137,000
Accumulated Depreciation	2,189,000
Office And Office/Flex Buildings [Member] | 125 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2002
Acquired	2002
Initial Costs, Land	1,055,000
Initial Costs, Building and Improvements	3,676,000
Costs Capitalized Subsequent to Acquisition	-515,000
Gross Amount at Which Carried at Close of Period, Land	1,055,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,161,000
Total	4,216,000
Accumulated Depreciation	947,000
Office And Office/Flex Buildings [Member] | 150 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1975
Acquired	1997
Initial Costs, Land	497,000
Initial Costs, Building and Improvements	7,030,000
Costs Capitalized Subsequent to Acquisition	2,211,000
Gross Amount at Which Carried at Close of Period, Land	497,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,241,000
Total	9,738,000
Accumulated Depreciation	3,820,000
Office And Office/Flex Buildings [Member] | 175 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1973
Acquired	1997
Initial Costs, Land	655,000
Initial Costs, Building and Improvements	7,473,000
Costs Capitalized Subsequent to Acquisition	676,000
Gross Amount at Which Carried at Close of Period, Land	655,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,149,000
Total	8,804,000
Accumulated Depreciation	3,946,000
Office And Office/Flex Buildings [Member] | 200 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1974
Acquired	1997
Initial Costs, Land	579,000
Initial Costs, Building and Improvements	6,620,000
Costs Capitalized Subsequent to Acquisition	1,778,000
Gross Amount at Which Carried at Close of Period, Land	579,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,398,000
Total	8,977,000
Accumulated Depreciation	3,573,000
Office And Office/Flex Buildings [Member] | 250 Clearbrook Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1973
Acquired	1997
Initial Costs, Land	867,000
Initial Costs, Building and Improvements	8,647,000
Costs Capitalized Subsequent to Acquisition	1,685,000
Gross Amount at Which Carried at Close of Period, Land	867,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	10,332,000
Total	11,199,000
Accumulated Depreciation	4,308,000
Office And Office/Flex Buildings [Member] | 50 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1969
Acquired	1997
Initial Costs, Land	237,000
Initial Costs, Building and Improvements	2,617,000
Costs Capitalized Subsequent to Acquisition	398,000
Gross Amount at Which Carried at Close of Period, Land	237,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,015,000
Total	3,252,000
Accumulated Depreciation	1,308,000
Office And Office/Flex Buildings [Member] | 77 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1977
Acquired	1997
Initial Costs, Land	34,000
Initial Costs, Building and Improvements	1,104,000
Costs Capitalized Subsequent to Acquisition	212,000
Gross Amount at Which Carried at Close of Period, Land	34,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,316,000
Total	1,350,000
Accumulated Depreciation	630,000
Office And Office/Flex Buildings [Member] | 85 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1968
Acquired	1997
Initial Costs, Land	155,000
Initial Costs, Building and Improvements	2,507,000
Costs Capitalized Subsequent to Acquisition	691,000
Gross Amount at Which Carried at Close of Period, Land	155,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,198,000
Total	3,353,000
Accumulated Depreciation	1,503,000
Office And Office/Flex Buildings [Member] | 300 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1970
Acquired	1997
Initial Costs, Land	460,000
Initial Costs, Building and Improvements	3,609,000
Costs Capitalized Subsequent to Acquisition	275,000
Gross Amount at Which Carried at Close of Period, Land	460,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,884,000
Total	4,344,000
Accumulated Depreciation	1,680,000
Office And Office/Flex Buildings [Member] | 350 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1970
Acquired	1997
Initial Costs, Land	100,000
Initial Costs, Building and Improvements	1,793,000
Costs Capitalized Subsequent to Acquisition	175,000
Gross Amount at Which Carried at Close of Period, Land	100,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,968,000	[1]
Total	2,068,000
Accumulated Depreciation	871,000	[2]
Office And Office/Flex Buildings [Member] | 399 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1962
Acquired	1997
Initial Costs, Land	531,000
Initial Costs, Building and Improvements	7,191,000
Costs Capitalized Subsequent to Acquisition	163,000
Gross Amount at Which Carried at Close of Period, Land	531,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,354,000	[1]
Total	7,885,000
Accumulated Depreciation	3,310,000	[2]
Office And Office/Flex Buildings [Member] | 400 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1970
Acquired	1997
Initial Costs, Land	2,202,000
Initial Costs, Building and Improvements	1,846,000
Costs Capitalized Subsequent to Acquisition	841,000
Gross Amount at Which Carried at Close of Period, Land	2,202,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,687,000	[1]
Total	4,889,000
Accumulated Depreciation	1,263,000	[2]
Office And Office/Flex Buildings [Member] | 500 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1970
Acquired	1997
Initial Costs, Land	258,000
Initial Costs, Building and Improvements	4,183,000
Costs Capitalized Subsequent to Acquisition	465,000
Gross Amount at Which Carried at Close of Period, Land	258,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,648,000	[1]
Total	4,906,000
Accumulated Depreciation	2,148,000	[2]
Office And Office/Flex Buildings [Member] | 525 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1972
Acquired	1997
Initial Costs, Land	345,000
Initial Costs, Building and Improvements	5,499,000
Costs Capitalized Subsequent to Acquisition	834,000
Gross Amount at Which Carried at Close of Period, Land	345,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,333,000	[1]
Total	6,678,000
Accumulated Depreciation	2,855,000	[2]
Office And Office/Flex Buildings [Member] | 1 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1967
Acquired	1997
Initial Costs, Land	199,000
Initial Costs, Building and Improvements	2,023,000
Costs Capitalized Subsequent to Acquisition	469,000
Gross Amount at Which Carried at Close of Period, Land	199,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,492,000	[1]
Total	2,691,000
Accumulated Depreciation	1,197,000	[2]
Office And Office/Flex Buildings [Member] | 2 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1968
Acquired	1997
Initial Costs, Land	234,000
Initial Costs, Building and Improvements	2,726,000
Costs Capitalized Subsequent to Acquisition	701,000
Gross Amount at Which Carried at Close of Period, Land	234,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,427,000	[1]
Total	3,661,000
Accumulated Depreciation	1,417,000	[2]
Office And Office/Flex Buildings [Member] | 3 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1969
Acquired	1997
Initial Costs, Land	655,000
Initial Costs, Building and Improvements	7,936,000
Costs Capitalized Subsequent to Acquisition	1,114,000
Gross Amount at Which Carried at Close of Period, Land	655,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,050,000	[1]
Total	9,705,000
Accumulated Depreciation	4,202,000	[2]
Office And Office/Flex Buildings [Member] | 4 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1969
Acquired	1997
Initial Costs, Land	320,000
Initial Costs, Building and Improvements	3,729,000
Costs Capitalized Subsequent to Acquisition	1,038,000
Gross Amount at Which Carried at Close of Period, Land	320,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,767,000	[1]
Total	5,087,000
Accumulated Depreciation	2,229,000	[2]
Office And Office/Flex Buildings [Member] | 5 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1969
Acquired	1997
Initial Costs, Land	118,000
Initial Costs, Building and Improvements	1,949,000
Costs Capitalized Subsequent to Acquisition	462,000
Gross Amount at Which Carried at Close of Period, Land	118,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,411,000	[1]
Total	2,529,000
Accumulated Depreciation	1,219,000	[2]
Office And Office/Flex Buildings [Member] | 6 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1968
Acquired	1997
Initial Costs, Land	164,000
Initial Costs, Building and Improvements	1,998,000
Costs Capitalized Subsequent to Acquisition	155,000
Gross Amount at Which Carried at Close of Period, Land	164,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,153,000	[1]
Total	2,317,000
Accumulated Depreciation	952,000	[2]
Office And Office/Flex Buildings [Member] | 7 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1972
Acquired	1997
Initial Costs, Land	286,000
Initial Costs, Building and Improvements	4,321,000
Costs Capitalized Subsequent to Acquisition	682,000
Gross Amount at Which Carried at Close of Period, Land	286,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,003,000	[1]
Total	5,289,000
Accumulated Depreciation	2,044,000	[2]
Office And Office/Flex Buildings [Member] | 8 Westchester Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1971
Acquired	1997
Initial Costs, Land	447,000
Initial Costs, Building and Improvements	5,262,000
Costs Capitalized Subsequent to Acquisition	1,932,000
Gross Amount at Which Carried at Close of Period, Land	447,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,194,000	[1]
Total	7,641,000
Accumulated Depreciation	2,875,000	[2]
Office And Office/Flex Buildings [Member] | 200 Saw Mill River Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1965
Acquired	1997
Initial Costs, Land	353,000
Initial Costs, Building and Improvements	3,353,000
Costs Capitalized Subsequent to Acquisition	608,000
Gross Amount at Which Carried at Close of Period, Land	353,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,961,000	[1]
Total	4,314,000
Accumulated Depreciation	1,786,000	[2]
Office And Office/Flex Buildings [Member] | 4 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1997
Initial Costs, Land	363,000
Initial Costs, Building and Improvements	7,513,000
Costs Capitalized Subsequent to Acquisition	2,790,000
Gross Amount at Which Carried at Close of Period, Land	363,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	10,303,000	[1]
Total	10,666,000
Accumulated Depreciation	4,874,000	[2]
Office And Office/Flex Buildings [Member] | 5 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Acquired	2001
Initial Costs, Land	2,219,000
Initial Costs, Building and Improvements	8,916,000
Costs Capitalized Subsequent to Acquisition	2,001,000
Gross Amount at Which Carried at Close of Period, Land	2,219,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	10,917,000	[1]
Total	13,136,000
Accumulated Depreciation	4,588,000	[2]
Office And Office/Flex Buildings [Member] | 6 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Acquired	2001
Initial Costs, Land	740,000
Initial Costs, Building and Improvements	2,971,000
Costs Capitalized Subsequent to Acquisition	1,044,000
Gross Amount at Which Carried at Close of Period, Land	740,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,015,000	[1]
Total	4,755,000
Accumulated Depreciation	2,142,000	[2]
Office And Office/Flex Buildings [Member] | 8 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1997
Initial Costs, Land	212,000
Initial Costs, Building and Improvements	4,410,000
Costs Capitalized Subsequent to Acquisition	951,000
Gross Amount at Which Carried at Close of Period, Land	212,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,361,000	[1]
Total	5,573,000
Accumulated Depreciation	2,577,000	[2]
Office And Office/Flex Buildings [Member] | 10 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1985
Acquired	1997
Initial Costs, Land	134,000
Initial Costs, Building and Improvements	2,799,000
Costs Capitalized Subsequent to Acquisition	732,000
Gross Amount at Which Carried at Close of Period, Land	134,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,531,000	[1]
Total	3,665,000
Accumulated Depreciation	1,757,000	[2]
Office And Office/Flex Buildings [Member] | 11 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1997
Initial Costs, Building and Improvements	4,788,000
Costs Capitalized Subsequent to Acquisition	760,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,548,000	[1]
Total	5,548,000
Accumulated Depreciation	2,252,000	[2]
Office And Office/Flex Buildings [Member] | 12 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1999
Acquired	1999
Initial Costs, Land	1,562,000
Initial Costs, Building and Improvements	3,254,000
Costs Capitalized Subsequent to Acquisition	21,000
Gross Amount at Which Carried at Close of Period, Land	1,320,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,517,000	[1]
Total	4,837,000
Accumulated Depreciation	1,368,000	[2]
Office And Office/Flex Buildings [Member] | 15 Skyline Drive [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1989
Acquired	1997
Initial Costs, Building and Improvements	7,449,000
Costs Capitalized Subsequent to Acquisition	628,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	8,077,000	[1]
Total	8,077,000
Accumulated Depreciation	3,544,000	[2]
Office And Office/Flex Buildings [Member] | 100 Corporate Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1997
Initial Costs, Land	602,000
Initial Costs, Building and Improvements	9,910,000
Costs Capitalized Subsequent to Acquisition	1,519,000
Gross Amount at Which Carried at Close of Period, Land	602,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	11,429,000	[1]
Total	12,031,000
Accumulated Depreciation	5,126,000	[2]
Office And Office/Flex Buildings [Member] | 200 Corporate Boulevard South [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1997
Initial Costs, Land	502,000
Initial Costs, Building and Improvements	7,575,000
Costs Capitalized Subsequent to Acquisition	1,538,000
Gross Amount at Which Carried at Close of Period, Land	502,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,113,000	[1]
Total	9,615,000
Accumulated Depreciation	4,107,000	[2]
Office And Office/Flex Buildings [Member] | 4 Executive Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1997
Initial Costs, Land	584,000
Initial Costs, Building and Improvements	6,134,000
Costs Capitalized Subsequent to Acquisition	942,000
Gross Amount at Which Carried at Close of Period, Land	584,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	7,076,000
Total	7,660,000
Accumulated Depreciation	3,285,000
Office And Office/Flex Buildings [Member] | 6 Executive Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1987
Acquired	1997
Initial Costs, Land	546,000
Initial Costs, Building and Improvements	7,246,000
Costs Capitalized Subsequent to Acquisition	2,146,000
Gross Amount at Which Carried at Close of Period, Land	546,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,392,000
Total	9,938,000
Accumulated Depreciation	3,882,000
Office And Office/Flex Buildings [Member] | 1 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Acquired	1997
Initial Costs, Land	1,206,000
Initial Costs, Building and Improvements	6,815,000
Costs Capitalized Subsequent to Acquisition	2,353,000
Gross Amount at Which Carried at Close of Period, Land	1,206,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	9,168,000
Total	10,374,000
Accumulated Depreciation	3,895,000
Office And Office/Flex Buildings [Member] | 5 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1983
Acquired	1997
Initial Costs, Land	331,000
Initial Costs, Building and Improvements	2,988,000
Costs Capitalized Subsequent to Acquisition	894,000
Gross Amount at Which Carried at Close of Period, Land	331,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,882,000
Total	4,213,000
Accumulated Depreciation	1,994,000
Office And Office/Flex Buildings [Member] | 7 Odell Plaza [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	1997
Initial Costs, Land	419,000
Initial Costs, Building and Improvements	4,418,000
Costs Capitalized Subsequent to Acquisition	1,045,000
Gross Amount at Which Carried at Close of Period, Land	419,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,463,000
Total	5,882,000
Accumulated Depreciation	2,281,000
Office And Office/Flex Buildings [Member] | 419 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1997
Initial Costs, Land	4,538,000
Initial Costs, Building and Improvements	9,246,000
Costs Capitalized Subsequent to Acquisition	1,295,000
Gross Amount at Which Carried at Close of Period, Land	4,538,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	10,541,000
Total	15,079,000
Accumulated Depreciation	4,956,000
Office And Office/Flex Buildings [Member] | 500 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	1997
Initial Costs, Land	415,000
Initial Costs, Building and Improvements	1,679,000
Costs Capitalized Subsequent to Acquisition	615,000
Gross Amount at Which Carried at Close of Period, Land	415,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,294,000
Total	2,709,000
Accumulated Depreciation	818,000
Office And Office/Flex Buildings [Member] | 550 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1990
Acquired	1997
Initial Costs, Land	1,975,000
Initial Costs, Building and Improvements	3,856,000
Costs Capitalized Subsequent to Acquisition	185,000
Gross Amount at Which Carried at Close of Period, Land	1,975,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	4,041,000
Total	6,016,000
Accumulated Depreciation	1,846,000
Office And Office/Flex Buildings [Member] | 600 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1999
Acquired	1999
Initial Costs, Land	2,305,000
Initial Costs, Building and Improvements	2,863,000
Costs Capitalized Subsequent to Acquisition	866,000
Gross Amount at Which Carried at Close of Period, Land	2,305,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,729,000
Total	6,034,000
Accumulated Depreciation	1,445,000
Office And Office/Flex Buildings [Member] | 650 West Avenue [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1998
Acquired	1998
Initial Costs, Land	1,328,000
Costs Capitalized Subsequent to Acquisition	3,503,000
Gross Amount at Which Carried at Close of Period, Land	1,328,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	3,503,000
Total	4,831,000
Accumulated Depreciation	1,438,000
Industrial/Warehouse Facilities [Member] | 1 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1957	[3]
Acquired	1997	[3]
Initial Costs, Land	3,000	[3]
Initial Costs, Building and Improvements	268,000	[3]
Costs Capitalized Subsequent to Acquisition	233,000	[3]
Gross Amount at Which Carried at Close of Period, Land	3,000	[3]
Gross Amount at Which Carried at Close of Period, Building and Improvements	501,000	[1],[3]
Total	504,000	[3]
Accumulated Depreciation	221,000	[2],[3]
Industrial/Warehouse Facilities [Member] | 2 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1957
Acquired	1997
Initial Costs, Land	4,000
Initial Costs, Building and Improvements	672,000
Costs Capitalized Subsequent to Acquisition	122,000
Gross Amount at Which Carried at Close of Period, Land	4,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	794,000	[1]
Total	798,000
Accumulated Depreciation	363,000	[2]
Industrial/Warehouse Facilities [Member] | 3 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1957
Acquired	1997
Initial Costs, Land	21,000
Initial Costs, Building and Improvements	1,948,000
Costs Capitalized Subsequent to Acquisition	363,000
Gross Amount at Which Carried at Close of Period, Land	21,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,311,000	[1]
Total	2,332,000
Accumulated Depreciation	1,114,000	[2]
Industrial/Warehouse Facilities [Member] | 4 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1957
Acquired	1997
Initial Costs, Land	84,000
Initial Costs, Building and Improvements	13,393,000
Costs Capitalized Subsequent to Acquisition	5,155,000
Gross Amount at Which Carried at Close of Period, Land	85,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	18,547,000	[1]
Total	18,632,000
Accumulated Depreciation	8,563,000	[2]
Industrial/Warehouse Facilities [Member] | 5 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1957
Acquired	1997
Initial Costs, Land	19,000
Initial Costs, Building and Improvements	4,804,000
Costs Capitalized Subsequent to Acquisition	939,000
Gross Amount at Which Carried at Close of Period, Land	19,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	5,743,000	[1]
Total	5,762,000
Accumulated Depreciation	2,551,000	[2]
Industrial/Warehouse Facilities [Member] | 6 Warehouse Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Acquired	1997
Initial Costs, Land	10,000
Initial Costs, Building and Improvements	4,419,000
Costs Capitalized Subsequent to Acquisition	2,445,000
Gross Amount at Which Carried at Close of Period, Land	10,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	6,864,000	[1]
Total	6,874,000
Accumulated Depreciation	2,592,000	[2]
Retail [Member] | 230 White Plains Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Acquired	1997
Initial Costs, Land	124,000
Initial Costs, Building and Improvements	1,845,000
Costs Capitalized Subsequent to Acquisition	107,000
Gross Amount at Which Carried at Close of Period, Land	124,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	1,952,000	[1]
Total	2,076,000
Accumulated Depreciation	868,000	[2]
Retail [Member] | 2 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1986
Acquired	1997
Initial Costs, Land	89,000
Initial Costs, Building and Improvements	2,439,000
Costs Capitalized Subsequent to Acquisition	100,000
Gross Amount at Which Carried at Close of Period, Land	89,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	2,539,000
Total	2,628,000
Accumulated Depreciation	1,113,000
Land Lease [Member] | 700 Executive Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	1997
Initial Costs, Land	970,000
Gross Amount at Which Carried at Close of Period, Land	970,000
Total	970,000
Land Lease [Member] | 1 Enterprise Boulevard [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	1997
Initial Costs, Land	1,379,000
Costs Capitalized Subsequent to Acquisition	1,000
Gross Amount at Which Carried at Close of Period, Land	1,380,000
Total	1,380,000
Land [Member] | Capital Office Park Parcel A [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Acquired	2009
Initial Costs, Land	840,000
Costs Capitalized Subsequent to Acquisition	7,000
Gross Amount at Which Carried at Close of Period, Land	847,000
Total	847,000
Multi-Family Properties [Member] | Richmond Court [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1997
Acquired	2013
Initial Costs, Land	2,992,000
Initial Costs, Building and Improvements	13,534,000
Costs Capitalized Subsequent to Acquisition	50,000
Gross Amount at Which Carried at Close of Period, Land	2,992,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	13,584,000
Total	16,576,000
Accumulated Depreciation	350,000
Multi-Family Properties [Member] | Riverwatch Commons [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Acquired	2013
Initial Costs, Land	4,169,000
Initial Costs, Building and Improvements	18,974,000
Costs Capitalized Subsequent to Acquisition	59,000
Gross Amount at Which Carried at Close of Period, Land	4,169,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	19,033,000
Total	23,202,000
Accumulated Depreciation	491,000
Multi-Family Properties [Member] | Park Square [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2011
Acquired	2013
Related Encumbrances	27,500,000
Initial Costs, Land	4,000,000
Initial Costs, Building and Improvements	40,670,000
Costs Capitalized Subsequent to Acquisition	21,000
Gross Amount at Which Carried at Close of Period, Land	4,000,000	[1]
Gross Amount at Which Carried at Close of Period, Building and Improvements	40,691,000
Total	44,691,000
Accumulated Depreciation	1,132,000
Multi-Family Properties [Member] | Alterra At Overlook Ridge IA [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2004
Acquired	2013
Initial Costs, Land	9,042,000
Initial Costs, Building and Improvements	50,671,000
Costs Capitalized Subsequent to Acquisition	357,000
Gross Amount at Which Carried at Close of Period, Land	9,042,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	51,028,000
Total	60,070,000
Accumulated Depreciation	2,535,000
Multi-Family Properties [Member] | Alterra At Overlook Ridge II [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2008
Acquired	2013
Initial Costs, Land	12,055,000
Initial Costs, Building and Improvements	71,409,000
Costs Capitalized Subsequent to Acquisition	345,000
Gross Amount at Which Carried at Close of Period, Land	12,055,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	71,754,000
Total	83,809,000
Accumulated Depreciation	3,332,000
Multi-Family Properties [Member] | Andover Place [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1988
Acquired	2014
Initial Costs, Land	8,535,000
Initial Costs, Building and Improvements	27,609,000
Costs Capitalized Subsequent to Acquisition	154,000
Gross Amount at Which Carried at Close of Period, Land	8,534,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	27,764,000
Total	36,298,000
Accumulated Depreciation	696,000
Other Property [Member] | 500 Avenue At Port Imperial [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2013
Acquired	2013
Related Encumbrances	36,600,000
Initial Costs, Land	13,099,000
Initial Costs, Building and Improvements	56,669,000
Costs Capitalized Subsequent to Acquisition	-21,005,000
Gross Amount at Which Carried at Close of Period, Land	13,099,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	35,664,000
Total	48,763,000
Accumulated Depreciation	1,282,000
Projects Under Development And Developable Land [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Related Encumbrances	68,359,000
Initial Costs, Land	174,581,000
Initial Costs, Building and Improvements	182,061,000
Gross Amount at Which Carried at Close of Period, Land	174,581,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	182,061,000
Total	356,642,000
Accumulated Depreciation	3,049,000
Furniture, Fixtures And Equipment [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Costs Capitalized Subsequent to Acquisition	12,055,000
Gross Amount at Which Carried at Close of Period, Building and Improvements	12,055,000
Total	12,055,000
Accumulated Depreciation	$3,515,000
Buildings And Improvements [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Depreciable life	40 years
Minimum [Member] | Office [Member] | 9200 Edmonston Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1973
Minimum [Member] | Office [Member] | 6301 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1979
Minimum [Member] | Office [Member] | 6303 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1980
Minimum [Member] | Office [Member] | 6305 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1982
Minimum [Member] | Office [Member] | 6411 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1984
Maximum [Member] | Office [Member] | 9200 Edmonston Road [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2003
Maximum [Member] | Office [Member] | 6301 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Maximum [Member] | Office [Member] | 6303 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2003
Maximum [Member] | Office [Member] | 6305 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	1995
Maximum [Member] | Office [Member] | 6411 Ivy Lane [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Year Built	2005
[1]	The aggregate cost for federal income tax purposes at December 31, 2014 was approximately $3.2 billion.
[2]	Depreciation of buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.
[3]	This property is located on land leased by the Company.

Real_Estate_Investments_And_Ac2

Real Estate Investments And Accumulated Depreciation (Schedule Of Changes In Rental Properties And Accumulated Depreciation) (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate Investments And Accumulated Depreciation [Abstract]
Rental Properties, Balance at beginning of year	$5,129,933	$5,379,436	$5,279,770
Rental Properties, Additions	193,005	317,994	296,079
Rental Properties, Rental property held for sale		-107,205	-84,716
Rental Properties, Properties sold	-331,181	-256,335	-34,563
Rental Properties, Impairment charge		-149,030	-20,573
Rental Properties, Retirements/disposals	-33,578	-54,927	-56,561
Rental Properties, Balance at end of year	4,958,179	5,129,933	5,379,436
Accumulated Depreciation, Balance at beginning of year	1,400,988	1,478,214	1,409,163
Accumulated Depreciation, Depreciation expense	143,278	155,846	157,175
Accumulated Depreciation, Rental property held for sale		-35,594	-23,852
Accumulated Depreciation, Properties sold	-96,383	-104,196	-10,026
Accumulated Depreciation, Impairment charge		-38,353	2,058
Accumulated Depreciation, Retirements/disposals	-33,578	-54,929	-56,304
Accumulated Depreciation, Balance at end of year	$1,414,305	$1,400,988	$1,478,214