Cover [Abstract] Statement [Table] Statement [Line Items] Document Type Amendment Flag Document Quarterly Report Document Transition Report Document Period End Date Entity Central Index Key Current Fiscal Year End Date Entity Registrant Name Document Fiscal Year Focus Document Fiscal Period Focus Entity File Number Entity Incorporation, State or Country Code Entity Tax Identification Number Entity Address, Address Line One Entity Address, Address Line Two Entity Address, City or Town Entity Address, State or Province Entity Address, Postal Zip Code City Area Code Local Phone Number Title of 12(b) Security Trading Symbol Security Exchange Name Entity Current Reporting Status Entity Interactive Data Current Entity Filer Category Entity Small Business Entity Emerging Growth Company Entity Shell Company Entity Common Stock, Shares Outstanding Consolidated Balance Sheets [Abstract] ASSETS Rental Property [Abstract] Rental Property [Abstract] Rental property Land And Leasehold Land And Leasehold Land and leasehold interests Buildings and improvements Tenant improvements Furniture, fixtures and equipment Gross investment in rental property Gross investment in rental property Book value Less - accumulated depreciation and amortization Less - accumulated depreciation and amortization Less: Accumulated depreciation Net book value Total investment in rental property Rental Property Held-for-sale, Net Rental Property Held-for-sale, Net Real estate held for sale, net Real estate held for sale, net Net Investment In Rental Property And Rental Property Held For Sale Net Investment In Rental Property And Rental Property Held For Sale Net investment in rental property Cash and cash equivalents, beginning of period Cash and cash equivalents Restricted Cash And Cash Equivalents Total restricted cash Restricted cash Carrying Amount Total investments in unconsolidated joint ventures Carrying Value Investments in unconsolidated joint ventures Unbilled rents receivable, net Other Assets Total deferred charges, goodwill and other assets, net Deferred charges, goodwill and other assets, net Accounts Receivable Net Accounts receivable Total assets Total assets LIABILITIES AND EQUITY Senior Notes Senior unsecured notes, net Revolving credit facility Unsecured revolving credit facility and term loans Amount outstanding Outstanding borrowings under the facility Secured Debt Mortgages, loans payable and other obligations, net Dividends and distributions payable Accounts payable, accrued expenses and other liabilities Amount at the balance sheet date including both: (a) rents and other amounts paid in advance by tenants and clients; and (b) security deposits paid in advance to protect the provider of a service, such as a lessor, against damage or nonpayment by the tenant (lessee) during the term of the agreement. Such damages may include physical damage to the property, theft of property, and other contractual breaches. Rents received in advance and security deposits Accrued interest payable Total liabilities Total liabilities Commitments And Contingencies 2009 Commitments and contingencies Redeemable Noncontrolling Interest, Equity, Fair Value Balance Balance Redeemable noncontrolling interests Equity: Stockholders' Equity Attributable to Parent [Abstract] Mack-Cali Realty Corporation stockholders' equity: Common stock value Common stock, $0.01 par value, 190,000,000 shares authorized, 90,729,703 and 90,712,417 shares outstanding Additional Paid In Capital Additional paid-in capital General Partners' Capital Account General Partner, 90,729,703 and 90,712,417 common units outstanding Limited Partners' Capital Account Limited partners, 8,980,338 and 9,649,031 common units/LTIPs outstanding Retained Earnings Accumulated Deficit Dividends in excess of net earnings Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive income (loss) Stockholders' Equity Attributable to Parent Balance Balance Total Mack-Cali Realty Corporation stockholders' equity Partners' Capital Total Mack-Cali Realty, L.P. partners' capital Noncontrolling Interest Items [Abstract] Noncontrolling interests in subsidiaries: Operating Partnership Minority Interest In Joint Ventures Consolidated joint ventures Total noncontrolling interests in subsidiaries Balance, value Balance, value Total noncontrolling interests in subsidiaries Total equity Balance, value Balance, value Total equity Partners' Capital Attributable to Noncontrolling Interest Noncontrolling interests in consolidated joint ventures Partners' Capital, Including Portion Attributable to Noncontrolling Interest Balance, value Balance, value Total equity Liabilities And Stockholders Equity Total liabilities and equity Common stock, par value per share Common stock, shares authorized Common Stock Shares Outstanding Common stock, shares outstanding General Partners' Capital Account, Units Outstanding General Partner common units outstanding Limited Partners' Capital Account, Units Outstanding Limited partners common units outstanding Consolidated Statements Of Operations [Abstract] Revenues Abstract REVENUES Operating Leases, Income Statement, Lease Revenue Revenue from leases Revenues Total revenues Total revenues EXPENSES Real estate taxes Construction and Development Costs Costs of the project incurred Utilities Operating services The aggregate costs including administrative paperwork, real estate brokerage, title, and property management operations. Costs Of Real Estate Services Real estate services expenses General and administrative Depreciation and amortization Depreciation and amortization Impairment Of Land And Other Impairment Of Land And Other Land and other impairments Land and other impairments Costs and Expenses Total expenses OTHER (EXPENSE) INCOME Interest expense Interest expense Total Amount of Interest Expense presented in the consolidated statements Investment Income (Loss), Nonoperating Investment Income (Loss), Nonoperating Interest and other investment income (loss) Equity in earnings (loss) of unconsolidated joint ventures Equity in (earnings) loss of unconsolidated joint ventures Equity in earnings (loss) of unconsolidated joint ventures Company's equity in earnings (loss) of unconsolidated joint ventures Realized gains on disposition of rental property Realized gains (losses) and unrealized gains (losses) on disposition of rental property, net Gain (Loss) On Sale Of Realized And Unrealized Property Plant Equipment Gain (Loss) On Sale Of Realized And Unrealized Property Plant Equipment Gain on disposition of developable land Gain on disposition of developable land Gain on disposition of developable land Nonoperating Income Expense Including Equity Method Investments Nonoperating Income Expense Including Equity Method Investments Total other income (expense) Income (loss) from continuing operations attributable to common shareholders Net income (loss) from continuing operations Discontinued Operations [Abstract] Discontinued operations: Income (loss) from discontinued operations for diluted earnings per share Income from discontinued operations Income from discontinued operations Realized gains (losses) on sales, net Realized gains (losses) and unrealized gains (losses) on disposition of rental property and impairments, net Realized gains (losses) and unrealized gains (losses) on disposition of rental property and impairments, net Income from properties sold Net (income) loss from discontinued operations Total discontinued operations, net Income (loss) from discontinued operations for diluted earnings per share Net income Net income (loss) Net income (loss) Noncontrolling interest in consolidated joint ventures Add (deduct): Noncontrolling interests in consolidated joint ventures Noncontrolling interests in consolidated joint ventures Noncontrolling interest in operating partnership Noncontrolling interests in Operating Partnership of income from continuing operations Noncontrolling interests in Operating Partnership Add (deduct): Noncontrolling interests in Operating Partnership Add (deduct): Noncontrolling interests in Operating Partnership Amount of net income (loss) for the period allocated to noncontrolling partners in discontinued operations included in the entity's consolidated financial statements. Noncontrolling interest in discontinued operations Noncontrolling interests in Operating Partnership in discontinued operations Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Redeemable noncontrolling interests Income Attributed to Noncontrolling Interests Net income (loss) available to common shareholders Net income (loss) available to common shareholders Basic earnings per common share: Income from continuing operations available to common shareholders Income (loss) from continuing operations available to common shareholders Income (loss) from continuing operations Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share Discontinued operations Income (loss) from discontinued operations available to common shareholders Earnings Per Share, Basic Net income (loss) available to common shareholders Net income (loss) available to common shareholders Diluted earnings per common share: Income Loss From Continuing Operations Per Diluted Share Income (loss) from continuing operations Income (loss) from continuing operations available to common shareholders Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share Discontinued operations Income (loss) from discontinued operations available to common shareholders Earnings Per Share Diluted Net income (loss) available to common shareholders Net income (loss) available to common shareholders Basic weighted average shares outstanding Basic EPS shares Weighted average common shares Diluted weighted average shares outstanding Weighted average common shares Diluted EPS Shares Weighted Average Limited Partnership Units Outstanding, Basic Basic EPU units Basic weighted average units outstanding Weighted average common units Weighted Average Limited Partnership Units Outstanding, Diluted Diluted EPU Units Diluted weighted average units outstanding Weighted average common unit Consolidated Statements Of Comprehensive Income (Loss) [Abstract] Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Net unrealized gain (loss) on derivative instruments for interest rate swaps Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income (loss) Comprehensive Income (Loss), Net Of Tax Attributable To Noncontrolling Interest Joint Venture Partners, Nonredeemable Comprehensive Income (Loss), Net Of Tax Attributable To Noncontrolling Interest Joint Venture Partners, Nonredeemable Comprehensive (income) loss attributable to noncontrolling interests in consolidated joint ventures Comprehensive Income Loss Net Of Tax Attributable To Redeemable Noncontrolling Interest Comprehensive Income Loss Net Of Tax Attributable To Redeemable Noncontrolling Interest Comprehensive (income) loss attributable to redeemable noncontrolling interests Comprehensive Income (Loss), Net Of Tax Attributable To, Noncontrolling Interest Operating Partnerships, Nonredeemable Comprehensive Income (Loss), Net Of Tax Attributable To, Noncontrolling Interest Operating Partnerships, Nonredeemable Comprehensive (income) loss attributable to noncontrolling interests in Operating Partnership Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive income (loss) attributable to common shareholders Consolidated Statements Of Changes In Equity [Abstract] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Additional Paid In Capital [Member] Additional Paid-In Capital [Member] Retained Earnings [Member] Dividends In Excess Of Net Earnings [Member] Noncontrolling Interest [Member] Noncontrolling Interests In Subsidiaries [Member] Shares, Issued Balance, shares Balance, shares Partners' Capital Account, Units Balance, units Balance, units Net Income (Loss), Including Portion Attributable to Nonredeemable Noncontrolling Interest Net income (loss) Common stock dividends Common stock dividends Common unit distributions Common unit distributions Common stock distributions Noncontrolling Interest, Increase from Distributions to Noncontrolling Interest Holders Noncontrolling Interest, Increase from Distributions to Noncontrolling Interest Holders Common unit distributions Redeemable Noncontrolling Interest Redemption Value Adjustment Redeemable Noncontrolling Interest Redemption Value Adjustment Redemption Value Adjustment Redeemable noncontrolling interests Noncontrolling Interest, Period Increase (Decrease) Change in noncontrolling interests in consolidated joint ventures Stock Issued During Period, Shares, Long-Term Incentive Plan Vested Stock Issued During Period, Shares, Long-Term Incentive Plan Vested Vested LTIP units, shares Redemption Of Common Units Redemption Of Common Units Redemption of common units, value Redemption of common units Redemption Of Common Units, Shares Redemption Of Common Units, Shares Redemption of common units, shares Shares issued under Dividend Reinvestment and Stock Purchase Plan, value Stock Dividends, Shares Shares issued under Dividend Reinvestment and Stock Purchase Plan, shares Stock Issued During Period, Value, Restricted Stock Award, Gross Directors' deferred compensation plan, value Directors' deferred compensation plan Adjustments To Additional Paid In Capital Sharebased Compensation Value Adjustments To Additional Paid In Capital Sharebased Compensation Value Stock compensation, value Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock compensation, shares Stock Repurchased and Retired During Period, Value Cancellation of common stock, value Stock Repurchased and Retired During Period, Shares Shares purchased and retired Cancellation of common stock, shares Stock Issued During Period, Value, Share-based Compensation, Forfeited Cancellation of restricted shares, value Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Cancellation of restricted shares, shares Shares forfeited and cancelled Other Comprehensive Income (Loss), Net of Tax Other comprehensive income (loss) Noncontrolling Interest, Increase (Decrease) from Subsidiary Equity Issuance Noncontrolling Interest, Increase (Decrease) from Subsidiary Equity Issuance Rebalancing of ownership percentage between parent and subsidiaries Rebalancing of ownership percent between parent and subsidiaries Consolidated Statements Of Cash Flows [Abstract] CASH FLOWS FROM OPERATING ACTIVITIES Adjustments to reconcile net income (loss) to net cash provided by Operating activities: Depreciation and amortization, including related intangible assets Amortization Of Deferred Stock Units Amortization Of Deferred Stock Units Amortization of directors deferred compensation stock units Stock compensation Amortization of stock compensation Amortization of deferred financing costs Amortization Of Debt Discount And Mark-To-Market Amortization Of Debt Discount And Mark-To-Market Amortization of debt discount and mark-to-market Equity Method Investment Dividends Or Distributions Distributions of cumulative earnings from unconsolidated joint ventures Realized Gains Loss On Disposition Of Assets, Net Realized Gains Loss On Disposition Of Assets, Net Realized (gains) losses and unrealized (gains) losses on disposition of rental property, net Impairment Of Land And Other Including Continued And Discontinued Operations Impairment Of Land And Other Including Continued And Discontinued Operations Land and other impairments Changes in operating assets and liabilities: Increase Decrease In Unbilled Rent Receivables Increase Decrease In Unbilled Rent Receivables Increase in unbilled rents receivable, net Increase in deferred charges and other assets, net (Increase) decrease in deferred charges, goodwill and other assets (Increase) decrease in accounts receivable, net Decrease (increase) in accounts receivable, net Increase (decrease) in accounts payable, accrued expenses and other liabilities Increase (decrease) in accounts payable, accrued expenses and other liabilities The net change during the reporting period in the amount at the balance sheet date including both: (a) rents and other amounts paid in advance by tenants and clients; and (b) security deposits paid in advance to protect the provider of a service, such as a lessor, against damage or nonpayment by the tenant (lessee) during the term of the agreement Increase Decrease In Rents Received In Advance And Security Deposits (Decrease) Increase in rents received in advance and security deposits Decrease in accrued interest payable Increase in accrued interest payable Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash flows provided by operating activities - continuing operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Net cash flows provided by operating activities - discontinuing operations Net cash provided by operating activities Net cash provided by operating activities CASH FLOWS FROM INVESTING ACTIVITIES Payments to Acquire Businesses, Net of Cash Acquired Rental property acquisitions and related intangibles Payments to Acquire and Develop Real Estate Rental property additions and improvements Purchase price of property Payments To Develop Property And Other Related Costs Payments To Develop Property And Other Related Costs Development of rental property and other related costs Net Sales Proceeds Proceeds from the sales of rental property Proceeds from the sale of property Proceeds from Collection of Loans Receivable Repayment of notes receivable Investment in unconsolidated joint ventures Investment in unconsolidated joint ventures This item represents the amount of distributions in excess of net earnings, which represents a return of investment, received from unconsolidated joint ventures and subsidiaries; these investments are accounted for under the equity method of accounting. Distributions In Excess Of Cumulative Earnings From Jvs Distributions in excess of cumulative earnings from unconsolidated joint ventures Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash used in investing activities - continuing operations Cash Provided by (Used in) Investing Activities, Discontinued Operations Net cash provided by investing activities - discontinuing operations Net cash used in investing activities Net cash provided by (used in) investing activities CASH FLOW FROM FINANCING ACTIVITIES Borrowings from revolving credit facility Repayment of revolving credit facility and money market loans Repayment of revolving credit facility Payment for borrowings Repayments of senior unsecured notes Repayment of senior unsecured notes Proceeds from Issuance of Secured Debt Proceeds from mortgages and loans payable Repayment of mortgages, loans payable and other obligations Repayment of mortgages, loans payable and other obligations Payments for Repurchase of Common Stock Common unit redemptions Payment of financing costs Payment of financing costs Proceeds from (Payments to) Noncontrolling Interests (Contributions) distributions to noncontrolling interests Payments for Repurchase of Redeemable Noncontrolling Interest Distributions to redeemable noncontrolling interests Payment of dividends and distributions Payment of common dividends and distributions Net cash provided used in financing activities Net cash provided by financing activities Net (decrease) increase in cash and cash equivalents Net increase (decrease) in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash, end of period Cash, cash equivalents and restricted cash, beginning of period Organization And Basis Of Presentation [Abstract] Organization And Basis Of Presentation [Table] Organization And Basis Of Presentation [Table] Organization And Basis Of Presentation [Line Items] Organization And Basis Of Presentation [Line Items] Organization Consolidation And Presentation Of Financial Statements Disclosure TextBlock Organization And Basis Of Presentation Significant Accounting Policies [Abstract] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant Accounting Policies Textblock Significant Accounting Policies Recent Transactions [Abstract] Recent Transactions [Abstract] Recent Transactions [Table] Recent Transactions [Table] Recent Transactions [Line Items] Recent Transactions [Line Items] Recent Transactions [Text Block] Recent Transactions [Text Block] Recent Transactions Investments In Unconsolidated Joint Ventures [Abstract] Investments In Unconsolidated Joint Ventures [Table] Investments In Unconsolidated Joint Ventures [Table] Investments In Unconsolidated Joint Ventures [Line Items] Investments In Unconsolidated Joint Ventures [Line Items] Equity Method Investments Disclosure TextBlock Investments In Unconsolidated Joint Ventures Deferred Charges, Goodwill And Other Assets, Net [Abstract] Deferred Charges, Goodwill And Other Assets [Table] Deferred Charges, Goodwill And Other Assets [Table] Deferred Charges, Goodwill And Other Assets [Line Items] Deferred Charges, Goodwill And Other Assets [Line Items] Deferred Costs Capitalized Prepaid And Other Assets Disclosure TextBlock Deferred Charges, Goodwill And Other Assets, Net Restricted Cash [Abstract] Restricted Cash [Table] Restricted Cash [Table] Restricted Cash [Line Items] Restricted Cash [Line Items] Restricted Assets Disclosure [Text Block] Restricted Cash Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Discontinued Operations Debt Disclosure [Abstract] Debt Disclosure [Table] Debt Disclosure [Table] Debt Disclosure [Line Items] Debt Disclosure [Line Items] Senior Unsecured Notes [Text Block] Senior Unsecured Notes [Text Block] Senior Unsecured Notes Schedule Of Line Of Credit Facilities TextBlock Unsecured Revolving Credit Facility And Term Loans Mortgages And Notes Payable [Text Block] Mortgages, Loans Payable And Other Obligations Employee Benefit 401(k) Plans [Abstract] Compensation And Retirement Disclosure [Table] Compensation And Retirement Disclosure [Table] Compensation And Retirement Disclosure [Line Items] Compensation And Retirement Disclosure [Line Items] GeneralDiscussionOfPensionAndOtherPostretirementBenefitsAbstract Employee Benefit 401(k) Plans Disclosure Of Fair Value Of Assets And Liabilities [Abstract] Fair Value Disclosures [Table] Fair Value Disclosures [Table] Fair Value Disclosures [Line Items] Fair Value Disclosures [Line Items] Fair Value Disclosures TextBlock Disclosure Of Fair Value Of Assets And Liabilities Commitments And Contingencies [Abstract] Commitments And Contingencies [Table] Commitments and Contingencies [Table] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments and Contingencies Disclosure Textblock Commitments And Contingencies Tenant Leases [Abstract] Leases [Table] Leases [Table] Leases [Line Items] Leases [Line Items] Lessor, Operating Leases [Text Block] Tenant Leases Redeemable Noncontrolling Interests [Abstract] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interests [Text Block] Redeemable Noncontrolling Interests [Text Block] Redeemable Noncontrolling Interests Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital [Abstract] Stockolders' Equity [Table] Stockolders Equity [Table] Stockholders Equity [Line Items] Stockholders Equity [Line Items] Stockholders Equity Note Disclosure TextBlock Mack-Cali Realty Corporation Stockholders' Equity And Mack-Cali Realty, L.P.'s Partners' Capital Noncontrolling Interests In Subsidiaries [Abstract] Noncontrolling Interest [Table] Noncontrolling Interest [Line Items] Minority Interest Disclosure TextBlock Noncontrolling Interests In Subsidiaries Segment Reporting [Abstract] Segment Reporting Information [Table] Segment Reporting Information [Table] Segment Reporting Information [Line Items] Segment Reporting Disclosure Textblock Segment Reporting Property, Plant and Equipment, Policy [Text Block] Rental Property Disclosure of the entity's accounting policy for declaring and paying dividends and distributions. Dividends And Distributions Payable Policy Text Block Dividends And Distributions Payable New Accounting Pronouncements, Policy [Policy Text Block] Impact Of Recently-Issued Accounting Standards Schedule Of Rental Property Improvements, Not In Service [Text Block] Schedule Of Rental Property Improvements, Not In Service [Text Block] Schedule Of Rental Property Improvements Schedule of Real Estate Properties [Table] Real Estate Properties [Line Items] Schedule Of Properties Which Commenced Initial Operations [Table Text Block] Schedule Of Properties Which Commenced Initial Operations [Table Text Block] Schedule Of Properties Which Commenced Initial Operations Schedule Of Real Estate Properties Sold [Table TextBlock] Schedule Of Real Estate Properties Sold [Table TextBlock] Schedule Of Disposed Properties Schedule Of Property Disposals, Not Part Of Discontinued Operations [Table Text Block] Schedule Of Property Disposals, Not Part Of Discontinued Operations [Table Text Block] Schedule Of Real Estate Held For Sale/Discontinued Operations/Dispositions Schedule Of Unconsolidated Joint Ventures [Table Text Block] Schedule Of Unconsolidated Joint Ventures [Table Text Block] Summary Of Unconsolidated Joint Ventures Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures Summary Of Company's Equity In Earnings (Loss) Of Unconsolidated Joint Ventures Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Other Assets [Table Text Block] Schedule Of Deferred Charges, Goodwill And Other Assets Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Schedule Of Cash Flow Hedging, Derivative Financial Instruments On The Income Statement Schedule of Restricted Cash and Cash Equivalents [Table Text Block] Schedule Of Restricted Cash Schedule Of Disposal Groups Including Discontinued Operations Income Statement Balance Sheet And Additional Disclosures Includes Disposition Of Rental Property And Impairments [Table Text Block] Schedule Of Disposal Groups Including Discontinued Operations Income Statement Balance Sheet And Additional Disclosures Includes Disposition Of Rental Property And Impairments [Table Text Block] Summary Of Income From Discontinued Operations And Related Realized And Unrealized Gains (Losses) (Details) Schedule of Long-term Debt Instruments [Table] Debt Instrument [Line Items] Schedule of Senior Unsecured Notes [Table Text Block] Summary Of Senior Unsecured Notes Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans And Facility Fee [Table Text Block] Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans And Facility Fee [Table Text Block] Schedule Of Defined Leverage Ratio, Including Interest Rate, Alternate Base Rate Loans, And Facility Fee Schedule Of Unsecured Credit Rating, Alternate Base Rate Loans And Credit Facility Fee, Operating Partnerships [Table Text Block] Schedule Of Unsecured Credit Rating, Alternate Base Rate Loans And Credit Facility Fee, Operating Partnerships [Table Text Block] Schedule Of Interest Rates On Outstanding Borrowings, Alternate Base Rate Loans, And Facility Fee Schedule Of Unsecured Credit Rating And Facility Fee, Operating Partnerships [Table Text Block] Schedule Of Unsecured Credit Rating And Facility Fee, Operating Partnerships [Table Text Block] Schedule Of Unsecured Credit Rating And Facility Fee Schedule Of Defined Leverage Ratio [Table Text Block] Schedule Of Defined Leverage Ratio [Table Text Block] Schedule Of Defined Leverage Ratio Schedule Of Unsecured Credit Rating, Operating Partnerships [Table Text Block] Schedule Of Unsecured Credit Rating, Operating Partnerships [Table Text Block] Schedule Of Interest Rate On Outstanding Borrowings Payable Schedule of Secured Debt [Table Text Block] Schedule of Secured Debt [Table Text Block] Summary Of Mortgages, Loans Payable And Other Obligations Fair Value Inputs, Assets, Quantitative Information [Table Text Block] Schedule Of Valuation Techniques And Significant Unobservable Assumptions Commitments And Contingencies Disclosure [Table] Commitments And Contingencies Disclosure [Table] Commitments And Contingencies Disclosure [Line Items] Commitments And Contingencies Disclosure [Line Items] Schedule Of Future Minimum Rental Payments For Operating Leases [Table Text Block] Future Minimum Rental Payments Of Ground Leases Lessor, Operating Lease, Payment to be Received, Fiscal Year Maturity [Table Text Block] Future Minimum Rentals To Be Received Under Non-Cancelable Operating Leases Redeemable Noncontrolling Interest [Table Text Block] Schedule Of Changes In The Value Of The Redeemable Noncontrolling Interests Schedule of Stockholders Equity [Table Text Block] Schedule Of General Partner Capital Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule Of Reconciliation Of Shares Used In Basic EPS Calculation To Shares Used In Diluted EPS Calculation Minority Interest [Table Text Block] Minority Interest [Table Text Block] Schedule Of Activity Of Noncontrolling Interests Schedule of Segment Reporting Information, by Segment [Text Block] Schedule Of Selected Results Of Operations And Asset Information Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block] Schedule Of Reconciliation Of Net Operating Income To Net Income Available To Common Shareholders Real Estate, Type of Property [Axis] Mortgage Loans On Real Estate Name Property Type [Domain] Real Estate [Domain] Unconsolidated Joint Venture Office Buildings [Member] Unconsolidated Joint Venture Office Buildings [Member] Unconsolidated Joint Venture Office Buildings [Member] Multi-Family Properties [Member] Multiple Family Properties [Member] Multi-Family Properties [Member] Unconsolidated Joint Venture Multiple Family Properties [Member] Unconsolidated Joint Venture Multiple Family Properties [Member] Unconsolidated Joint Venture Multi-Family Properties [Member] Unconsolidated Joint Venture Office/Flex Buildings And Hotel [Member] Unconsolidated Joint Venture Office Flex Buildings And Hotel [Member] Unconsolidated Joint Venture Office/Flex Buildings And Hotel [Member] Parking/Retail [Member] Parking Retail [Member] Parking/Retail [Member] Unconsolidated Joint Venture Parking/Retail Buildings [Member] Unconsolidated Joint Venture Parking Retail Buildings [Member] Unconsolidated Joint Venture Parking/Retail Buildings [Member] Land [Member] Land [Member] General Partner Ownership Percentage General Partner Ownership Percentage Percentage of ownership interest Real Estate Property Owned and Investment Interest Real Estate Property Owned and Investment Interest Number of properties owned or investment interests Real Estate Property Owned and Investment Interest, Area Real Estate Property Owned and Investment Interest, Area Aggregate square feet of the property owned or investment interest Number Of Tenants Number Of Tenants Number of tenants Number Of Units Total number of Apartment Units Number of Apartment Units Number of units Real Estate Property Owned or Investment Interest, Number of Location Real Estate Property Owned or Investment Interest, Number of Location Number of states where properties are located Consolidated Joint Ventures Real Estate Assets Consolidated Joint Ventures Real Estate Assets Consolidated joint ventures, total real estate assets Consolidated Joint Ventures Other Assets Consolidated Joint Ventures Other Assets Consolidated joint ventures, other assets Consolidated Joint Ventures Mortgages Consolidated Joint Ventures Mortgages Consolidated joint ventures, mortgages Consolidated Joint Ventures Other Liabilities Consolidated Joint Ventures Other Liabilities Consolidated joint ventures, other liabilities Area Of Real Estate Property Area of property (in square feet) Rentable Square Feet (sf) Area of property (in square feet) Capitalized Development, Construction Salaries And Other Related Expenses Capitalized Development, Construction Salaries And Other Related Expenses Capitalized development and construction salaries and other related costs Maximum Period After Cessation Of Major Construction Activity That Projects Are Considered Complete Maximum Period After Cessation Of Major Construction Activity That Projects Are Considered Complete Maximum period after cessation of major construction activity that projects are considered complete Gains (Losses) on Extinguishment of Debt Gain (Loss) from extinguishment of debt, net Property, Plant and Equipment [Line Items] Land and Land Improvements Land held for development (including pre-development costs, if any) Development And Construction In Progress, Including Land Development And Construction In Progress, Including Land Development and construction in progress, including land Property, Plant and Equipment, Gross Total Buildings And Improvements, Net Of Accumulated Depreciation Buildings And Improvements, Net Of Accumulated Depreciation Buildings and improvement Land Land Real Estate Development Costs Incurred Real Estate Development Costs Incurred Total Development Costs Incurred Development costs Number of real estate properties Number of properties Number Of Real Estate Properties Held For Sale Number Of Real Estate Properties Held For Sale Number of properties held for sale Unrealized Gain (Loss) on Investments Unrealized gains (losses) on real estate held for sale Number Of Properties Sold Number Of Properties Sold Number of properties sold Area Of Real Estate Property Sold Area Of Real Estate Property Sold Rentable Square Feet Gain (Loss) on Disposition of Real Estate, Discontinued Operations Gain (loss) on sale of property Realized Gains (losses)/Unrealized Losses, net Number Of Disposal Groups Number Of Disposal Groups Number of disposal groups Proceeds from Sale of Buildings, Net Proceeds from Sale of Buildings, Net Net proceeds Repayments of Long-term Debt Repayment of debt Number of Units in Real Estate Property In Operations Number of Units in Real Estate Property In Operations Number of Apartment Units Number Of Restaurant Tenants Number Of Restaurant Tenants Number of restaurant tenants Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Land Available-for-sale Land Buildings And Improvements Available For Sale Buildings And Improvements Available For Sale Buildings & Other Unrealized Gain Loss On Investments Held For Sale Unrealized Gain Loss On Investments Held For Sale Less: Cumulative unrealized losses on property held for sale Assets Held-for-sale, Not Part of Disposal Group, Deferred Rent Receivables, Net Assets Held-for-sale, Not Part of Disposal Group, Deferred Rent Receivables, Net Unbilled rents receivable, net Assets Held-for-sale, Not Part of Disposal Group, Deferred Charges, Net Assets Held-for-sale, Not Part of Disposal Group, Deferred Charges, Net Deferred charges, net Assets Held-for-sale, Not Part of Disposal Group, Total Intangibles, Net Assets Held-for-sale, Not Part of Disposal Group, Total Intangibles, Net Total intangibles, net Assets Held-for-sale, Not Part of Disposal Group, Deferred Charges And Other Assets Assets Held-for-sale, Not Part of Disposal Group, Deferred Charges And Other Assets Total deferred charges & other assets, net Assets Held-for-sale, Not Part of Disposal Group, Mortgages & Loans Payable, Net Assets Held-for-sale, Not Part of Disposal Group, Mortgages & Loans Payable, Net Mortgages & loans payable, net Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Total Below Market Liability Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Total Below Market Liability Total below market liability Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Accrued Expenses And Other Liabilities Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Accrued Expenses And Other Liabilities Accounts payable, accrued exp & other liability Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Unearned Rents/Deferred Rental Income Assets Held-for-sale, Not Part of Disposal Group, Accounts Payable, Unearned Rents/Deferred Rental Income Unearned rents/deferred rental income Disposal Group Name [Axis] Disposal Groups Including Discontinued Operations Name [Domain] Disposal Groups, Including Discontinued Operations, Name [Domain] Metropark Portfolio [Member] Metropark Portfolio [Member] Metropark Portfolio [Member] Number Of Buildings On Properties Sold Number of buildings on properties sold Number of buildings Number of properties sold Proceeds from Sale of Real Estate Held-for-investment Net Sales Proceeds Sales proceeds Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Net Value Disposal Group, Including Discontinued Operation, Property, Plant and Equipment, Net Value Net Carrying Value Gain (Loss) On Disposition Of Real Estate Discontinued Operations, Net Of Unrealized Gain (Losses) Gain (Loss) On Disposition Of Real Estate Discontinued Operations, Net Of Unrealized Gain (Losses) Totals Partners' Capital Account, Value, Units Redeemed Partners' Capital Account, Value, Units Redeemed Value of units redeemed Schedule of Equity Method Investments [Table] Investments by Consolidated and Nonconsolidated Entities [Axis] Investments By Consolidated And Nonconsolidated Entities [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity Not Primary Beneficiary [Member] Variable Interest Entity [Member] Statistical Measurement [Axis] Range [Member] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Unconsolidated Joint Venture Retail Buildings [Member] Unconsolidated Joint Venture Retail Buildings [Member] Unconsolidated Joint Venture Retail Buildings [Member] Unconsolidated Joint Venture Hotel [Member] Unconsolidated Joint Venture Hotel [Member] Unconsolidated Joint Venture Hotel [Member] Unconsolidated Joint Venture Development Projects [Member] Unconsolidated Joint Venture Development Projects [Member] Unconsolidated Joint Venture Development Projects [Member] Unconsolidated Joint Venture Land Parcels [Member] Unconsolidated Joint Venture Land Parcels [Member] Unconsolidated Joint Venture Land Parcels [Member] Unconsolidated Joint Ventures [Member] Unconsolidated Joint Ventures [Member] Unconsolidated Joint Ventures [Member] Unconsolidated Joint Venture Property [Member] Unconsolidated Joint Venture Property [Member] Unconsolidated Joint Venture Property [Member] Schedule of Equity Method Investments [Line Items] Area Of Mixed Use Property Area Of Mixed Use Property Area of mixed use project (in square feet) Equity Method Investment, Ownership Percentage Percentage of interest in venture Company's Effective Ownership % Maximum borrowing capacity Borrowing capacity under the credit facility Management, Leasing, Development And Other Services Fees Management, Leasing, Development And Other Services Fees Management, leasing, development and other services fees Due from Joint Ventures Accounts receivable due from unconsolidated joint ventures Number Of Variable Interest Entities Number Of Variable Interest Entities Number of VIEs Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Maximum exposure to loss Variable Interest Entity, Entity Estimated Future Funding Commitments Variable Interest Entity, Entity Estimated Future Funding Commitments Estimated future funding commitments Property Debt, Interest Rate Interest rate Interest rate of senior unsecured notes Mortgage Loan Maturity Date Mortgage Loan Maturity Date Mortgage loan, maturity date Property Debt, Maturity Date Long-term Line of Credit, Maximum Guaranteed Amount Long-term Line of Credit, Maximum Guaranteed Amount Maximum guaranteed amount Long-term Line of Credit, Guaranteed Amount Long-term Line of Credit, Guaranteed Amount Guaranteed amount Name of Property [Axis] Real Estate And Accumulated Depreciation Name Of Property [Domain] Name of Property [Domain] The Shops At Forty Park Property [Member] Shops At Forty Park Property [Member] The Shops At 40 Park Property [Member] Lofts At 40 Park Property [Member] Lofts At Forty Park Property [Member] Lofts At 40 Park Property [Member] Metropolitan Property [Member] Metropolitan Property [Member] Metropolitan Property [Member] Investment, Name [Axis] Equity Method Investee Name [Domain] Equity Method Investee, Name [Domain] 12 Vreeland Associates, L.L.C. [Member] Twelve Vreeland Associates L L C [Member] 12 Vreeland Road [Member] Metropolitan At 40 Park [Member] Metropolitan At40 Park [Member] Metropolitan And Lofts At 40 Park [Member] RiverTrace At Port Imperial [Member] Rivertrace At Port Imperial [Member] RiverTrace At Port Imperial [Member] Offices At Crystal Lake [Member] Offices At Crystal Lake [Member] Offices At Crystal Lake [Member] Hyatt Regency Jersey City [Member] Hyatt Regency Jersey City [Member] Hyatt Regency Hotel Jersey City [Member] Riverpark At Harrison [Member] Riverpark At Harrison [Member] Riverpark At Harrison [Member] Station House [Member] Station House [Member] Station House [Member] Urby At Harborside [Member] Urby At Harborside [Member] Urby At Harborside [Member] PI North - Land [Member] Pi North Land [Member] PI North - Land [Member] Liberty Landing [Member] Liberty Landing [Member] Liberty Landing [Member] PI North - Riverwalk [Member] Pi North Riverwalk [Member] PI North - Riverwalk C [Member] Other Joint Ventures [Member] Other Joint Ventures [Member] Other [Member] Mortgage Loans on Real Estate Balance Mortgage loan Property Debt, Interest Rate, Spread Over LIBOR Spread over LIBOR Interest Rate - Applicable Basis Points Above LIBOR Residual Ownership Interest Residual Ownership Interest Residual ownership interest Indirect Ownership Percentage Indirect Ownership Percentage Indirect ownership interest Number Of Properties In Which Additional Interest Was Acquired During Period Number Of Properties In Which Additional Interest Was Acquired During Period Number of properties in which additional interest was acquired during period Number Of Stories In Real Estate Property Number Of Stories In Real Estate Property Number of stories Mortgage Loan On Real Estate, Additional Borrowing Capacity Mortgage Loan On Real Estate, Additional Borrowing Capacity Additional borrowing capacity Debt Instrument, Number Of Extension Options Debt Instrument, Number Of Extension Options Number of extension options Debt Instrument Extension Period Debt Instrument Extension Period Loan extension period Debt Instrument Extension Fee Percentage Debt Instrument Extension Fee Percentage Extension fee Debt Instrument, Interest Rate, Effective Percentage Effective rate Internal Rate of Return Internal rate of return Internal rate of return Mortgage loan, maturity date Loan maturity date Maturity date of the senior unsecured notes Preferred Units, Issued Preferred units shares issued Gain on Sale of Investments Gain on sale Mortgage Loan Maturity Month And Year Mortgage Loan Maturity Month And Year Mortgage loan, maturity month and year Impairment of Real Estate Property impairments Property impairments on continuing operations Percent Of Line of Credit Outstanding Percent Of Line of Credit Outstanding Percent of principal loan outstanding Crystal House Apartments Investors LLC [Member] Crystal House Apartments Investors L L C [Member] Crystal House [Member] Equity Method Investment, Amortization Of Basis Difference Equity Method Investment, Amortization Of Basis Difference Amortization of basis difference Derivative Instruments, Gain (Loss) [Table] Derivative Instruments, Gain (Loss) [Line Items] Derivative Liability, Notional Amount Derivative notional amount Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Estimated additional amount to be reclassified to interest expense Derivative Liability, Fair Value, Gross Liability Net liability Deferred Costs, Leasing, Gross Deferred leasing costs Deferred Finance Costs, Gross Deferred financing costs - unsecured revolving credit facility Deferred Costs, Gross Deferred Costs, Gross Deferred charges, gross Accumulated Amortization Leasing And Financing Costs Accumulated Amortization Leasing And Financing Costs Accumulated amortization Deferred charges, net Deferred charges, net Loans and Leases Receivable, Net Amount Notes receivable Finite-Lived Intangible Asset, Acquired-in-Place Leases In-place lease values, related intangibles and other assets, net Business Acquisition, Purchase Price Allocation, Goodwill Amount Goodwill Assets Right-Of-Use Assets Right-Of-Use Right of use assets Prepaid expenses and other assets, net Assets Right Of Use, Liability Assets Right Of Use, Liability Liability Annual Return On The Equity Value Annual Return On The Equity Value Annual return on the equity value Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income Security Deposit Security deposits Escrow Deposit Escrow and other reserve funds Number Of Properties, Unrealized Loss Number Of Properties, Unrealized Loss Properties Unrealized Gain Loss On Disposition Of Rental Property Unrealized Gain Loss On Disposition Of Rental Property Unrealized gains (losses) on disposition of rental property Disposal Group, Including Discontinued Operation, Revenue Total revenues Disposal Group Including Discontinued Operation Operating Expense Operating and other expenses Depreciation Amortization On Discontinued Operations Depreciation Amortization On Discontinued Operations Depreciation and amortization Disposal Group, Including Discontinued Operation, Interest Expense Interest expense Disposal Group, Including Discontinued Operation, Gain Loss On Disposition Of Assets Disposal Group, Including Discontinued Operation, Gain Loss On Disposition Of Assets Realized gains (losses) on disposition of rental property Long-term Debt, Gross Loan balance Principal balance outstanding Debt Instrument, Unamortized Discount Adjustment for unamortized debt discount Unamortized Deferred Financing Costs Unamortized Deferred Financing Costs Unamortized deferred financing costs Unamortized deferred financing costs Long-term Debt Total indebtedness Total debt Line of Credit Facility [Table] Line of Credit Facility [Line Items] Unsecured Long-term Debt, Noncurrent Unsecured term loan, net Line of Credit Facility, Lending Institutions Number Line of Credit Facility, Lending Institutions Number Number of lending institutions Line of Credit Facility, Expiration Month And Year Line of Credit Facility, Expiration Month And Year Credit facility maturity month and year Line Of Credit Facility Extension Period Line Of Credit Facility Extension Period Credit facility, extension period Line Of Credit Facility Basis Point Facility Fee Line Of Credit Facility Basis Point Facility Fee Credit facility extension fee, basis points Debt Instrument Covenant Compliance, Leverage Ratio Debt Instrument Covenant Compliance, Leverage Ratio Leverage ratio Debt Instrument Covenant Compliance, Secured Indebtedness Debt Instrument Covenant Compliance, Secured Indebtedness Secured indebtedness Debt Instrument Covenant Compliance, Fixed Charge Coverage Debt Instrument Covenant Compliance, Fixed Charge Coverage Fixed charge coverage ratio Debt Instrument Covenant Compliance, Unsecured Indebtedness Debt Instrument Covenant Compliance, Unsecured Indebtedness Unsecured indebtedness Debt Instrument Covenant Compliance, Unencumbered Property Interest Coverage Debt Instrument Covenant Compliance, Unencumbered Property Interest Coverage Unencumbered property interest coverage Debt Instrument Covenant Compliance, Investment Limitations As Percentage Of Total Capitalization Debt Instrument Covenant Compliance, Investment Limitations As Percentage Of Total Capitalization Investment limitations as a percentage of total capitalization Line of Credit Facility, Covenant Terms Terms of the unsecured facility Line of Credit Facility, Dividend Restrictions Terms of dividend restriction Debt Instrument, Term Loan period Debt Instrument, Initial Term Commitment Percentage Borrowed Debt Instrument, Initial Term Commitment Percentage Borrowed Minimum percentage of initial borrowing Debt Instrument, Term Commitment Fee Per Annum Debt Instrument, Term Commitment Fee Per Annum Term commitment fee percent Line of Credit Facility, Basis Points of Facility Fees Facility fee basis points Facility Fee Basis Points Debt Instrument, Extension Fee Amount Debt Instrument, Extension Fee Amount Extension fee amount Gain (Loss) on Early Termination of Debt Gain (Loss) on Early Termination of Debt Gain on early termination Credit Facility, Maturity Month and Year Credit Facility, Maturity Month and Year Credit facility, Maturity month and year Proceeds from Lines of Credit Proceeds from Letters of Credit Secured Long-term Debt, Noncurrent Secured debt Unencumbered Property Appraisal Value Unencumbered Property Appraisal Value Appraisal value Debt Instrument, Maximum Collateral Pool Leverage Ratio Debt Instrument, Maximum Collateral Pool Leverage Ratio Maximum collateral pool leverage ratio Debt Instrument, Number Of Collateral Pool Properties Debt Instrument, Number Of Collateral Pool Properties Number of collateral pool properties Debt Instrument, Total Leverage Ratio Debt Instrument, Total Leverage Ratio Total leverage ratio Debt Instrument, Debt Service Coverage Ratio Debt Instrument, Debt Service Coverage Ratio Debt service coverage ratio Debt Instrument, Tangible Net Worth Ratio Debt Instrument, Tangible Net Worth Ratio Tangible net worth ratio Percentage Of Net Cash Proceeds Of Equity Issuances Percentage Of Net Cash Proceeds Of Equity Issuances Percentage of net cash proceeds of equity issuances Debt Instrument, Credit Rating Unsecured Debt Ratings Debt Instrument [Axis] Debt Instrument Name [Domain] Debt Instrument, Name [Domain] Revolving Credit Facility and Other Variable Rate Mortgage Debt [Member] Revolving Credit Facility And Other Variable Rate Mortgage Debt [Member] Revolving Credit Facility Borrowing And Other Variable Rate Mortgage Debt [Member] Fixed Rate Debt and Other Obligations [Member] Fixed Rate Debt And Other Obligations [Member] Fixed Rate Debt And Other Obligations [Member] Number Of Properties With Encumbered Company Mortgages Number Of Properties With Encumbered Company Mortgages Number of properties with encumbered company mortgages Number Of Projects With Encumbered Company Mortgages Number Of Projects With Encumbered Company Mortgages Number of projects with encumbered company mortgages Carrying Value of the Mortgaged Property Mortgage Property, Carrying Value Carrying value of encumbered properties Interest Paid Cash paid for interest Interest Costs, Capitalized During Period Interest capitalized Long-term Debt, Weighted Average Interest Rate Total indebtedness, weighted average interest rate Port Imperial Four Five Hotel [Member] Port Imperial Four Five Hotel [Member] Port Imperial 4/5 Hotel [Member] Emery At Overlook Ridge [Member] Emery At Overlook Ridge [Member] Emery At Overlook Ridge [Member] Port Imperial South Nine [Member] Port Imperial South Nine [Member] Port Imperial South 9 [Member] Secured Debt, Name of the Property Secured Debt, Name of the Property Property Name Secured Debt, Lending Institution Secured Debt, Lending Institution Lender Debt, Loans Payable, And Other Obligations, Net Debt, Loans Payable, And Other Obligations, Net Total mortgages, loans payable and other obligations, net Debt Instrument, Interest Rate, Effective Percentage After Five Years Debt Instrument, Interest Rate, Effective Percentage After Five Years Effective percentage after five years Interest Expense, Debt Deferred interest Debt Instrument, Deferred Interest And Payment, Maturity Date Debt Instrument, Deferred Interest And Payment, Maturity Date Deferred interest and payment end date Schedule of Deferred Compensation Arrangement with Individual, Postretirement Benefits [Table] Deferred Compensation Arrangement with Individual, Postretirement Benefits [Line Items] Savings Retirement Plan Employee Minimum Subscription Rate Savings Retirement Plan Employee Minimum Subscription Rate Minimum employee subscription rate, percentage of compensation Savings Retirement Plan Employee Maximum Subscription Rate Savings Retirement Plan Employee Maximum Subscription Rate Maximum employee subscription rate, percentage of compensation Employee pre-tax contributions vested percent. Employee Pre Tax Contributions Vested Percent Employee pre-tax contributions vested percentage Savings Retirement Plan Vesting Period Savings Retirement Plan Vesting Period Employer contribution vesting period Vesting rate Vesting Rate Vesting rate Percent vested after total service period. Percent Vested After Total Service Period Percentage vested after total service period Savings Retirement Plan Vesting Rights Savings Retirement Plan Vesting Rights Employees' vesting rights Employee Benefits and Share-based Compensation Expenses for employee benefit plan Fair Value Measurement Inputs and Valuation Techniques [Table] Fair Value Measurement Inputs and Valuation Techniques [Line Items] Debt Instrument, Fair Value Fair value of Company's long-term debt Property Net Book Value Property Net Book Value Properties aggregate net book value Office Held For Sale, Measurement Input Office Held For Sale, Measurement Input Office properties held for sale Land Properties Held For Sale, Measurement Input Land Properties Held For Sale, Measurement Input Land properties held for sale Harborside Financial Center Plaza 4-A [Member] Harborside Financial Center Plaza Foura [Member] Harborside Plaza 4-A [Member] Harborside Financial Center Plaza 5 [Member] Harborside Financial Center Plaza Five [Member] Harborside Plaza 5 [Member] Port Imperial South One Third Garage Development [Member] Port Imperial South One Third Garage Development [Member] Port Imperial South 1/3 Garage [Member] Project Term Project Term Project period Payments in Lieu of Property Tax As Percentage of Total Project Cost Payments in Lieu of Property Tax As Percentage of Total Project Cost Percentage of PILOT on project costs Estimated Cost Of Project Estimated Cost Of Project Total project costs Payments In Lieu Of Property Taxes Payments In Lieu Of Property Taxes Payments in lieu of property taxes (PILOT) Payments In Lieu Of Property Taxes, Annual Payment Payments In Lieu Of Property Taxes, Annual Payment Annual Payments in lieu of property taxes (PILOT) Payments In Lieu Of Property Tax As Percentage Based On The Land Value Payments In Lieu Of Property Tax As Percentage Based On Land Value Percentage of taxes paid based on the land value Annual Percentage Of Cost For Phase In Annual Percentage Of Cost For Phase In Annual percentage of cost for phase in Payments In Lieu Of Property Tax As Percentage Of Gross Revenues Payments In Lieu Of Property Tax As Percentage Of Gross Revenues Percentage of PILOT on gross revenues Lessee, Lease, Description [Table] Lessee, Lease, Description [Line Items] Operating Lease, Expense, Including Sublease Rentals Operating Lease, Expense, Including Sublease Rentals Ground lease expense incurred Operating Lease, Liability Operating lease Total Operating Lease, Number of Units Operating Lease, Number of Units Number of ground leases Lessee, Finance Lease, Term of Contract Term of lease contract Lessee, Operating Lease, Discount Rate Borrowing rate Construction Costs Incurred Construction Costs Incurred Construction costs incurred Delivery date of constructed building Delivery Date Of Constructed Building Delivery date to tenant Amount To Fund Amount To Fund Amount to fund Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Shares Under Options - Granted Shares granted Annual Bonus Opportunity Percentage Annual Bonus Opportunity Percentage Annual bonus opportunity percentage Annual Base Salary Annual Base Salary Annual base salary Annual Bonus Opportunity Threshold Percentage Annual Bonus Opportunity Threshold Percentage Annual bonus opportunity threshold percentage Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Annual Aggregate Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Annual Aggregate Grant Date Fair Value Annual Aggregate grant date fair value Share Based Compensation Arrangement By Share-based Payment Award Performance Period Share Based Compensation Arrangement By Share-based Payment Award Performance Period Performance period Annual Health Coverage Annual Health Coverage Annual health coverage Annual Tax Compliance Assistance Annual Tax Compliance Assistance Annual tax compliance assistance Reimbursement Of Attorneys' Fees To Negotiate The Employment Agreement Reimbursement Of Attorneys' Fees To Negotiate The Employment Agreement Reimbursement of attorneys' fees to negotiate the Employment Agreement Reimbursement For Relocation Costs Reimbursement For Relocation Costs Reimbursement for relocation costs Monthly Salary and Wage, Officer Monthly Salary and Wage, Officer Monthly fee One-time Cash Sign-On Bonus One-time Cash Sign-On Bonus One-time bonus One-time Completion Bonus One-time Completion Bonus One-time completion bonus Restructuring Costs Restructuring costs Employee Agreement Period Employee Agreement Period Employee agreement Property, Plant and Equipment by Type [Axis] Property Plant And Equipment Type [Domain] Property, Plant and Equipment, Type [Domain] Property Lock-Ups Expired [Member] Property Lock Ups Expired [Member] Property Lock-Ups Expired [Member] Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Percent Of Estimated Net Asset Value Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Percent Of Estimated Net Asset Value Percent of estimated net asset Number Of Employee Number Of Employee Number of employees Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Potential shares Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Exercisable time period Number Of Payments Number Of Payments Number of payments Reimbursement Of Expenses Reimbursement Of Expenses Reimbursement expense Stay On Award Agreement Costs Stay On Award Agreement Costs Stay on award agreement cost Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Remaining Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months Year one Lessee, Operating Lease, Liability, Payments, Due Year Two Year two Lessee, Operating Lease, Liability, Payments, Due Year Three Year three Lessee, Operating Lease, Liability, Payments, Due Year Four Year four Lessee, Operating Lease, Liability, Payments, Due Year Five Year five Lessee, Operating Lease, Liability, Payments, Due after Year Five 2026 through 2101 Lessee, Operating Lease, Liability, to be Paid Total lease payments Lessee, Operating Lease, Liability, Undiscounted Excess Amount Less: imputed interest Property Subject to or Available for Operating Lease, by Major Property Class [Table] Property Subject to or Available for Operating Lease [Axis] Property Subject To Or Available For Operating Lease [Domain] Property Subject to or Available for Operating Lease [Domain] Tenant Leases [Member] Tenant Leases [Member] Tenant Leases [Member] Property Subject to or Available for Operating Lease [Line Items] Lessor, Operating Lease, Payment to be Received, Remainder of Fiscal Year April 1 through December 31, 2021 Lessor, Operating Lease, Payment to be Received, Year One Year one Lessor, Operating Lease, Payment to be Received, Year Two Year two Lessor, Operating Lease, Payment to be Received, Year Three Year three Lessor, Operating Lease, Payment to be Received, Year Four Year four Lessor, Operating Lease, Payment to be Received, Year Five Year Five Lessor, Operating Lease, Payment to be Received, after Year Five 2026 and thereafter Lessor, Operating Lease, Payments to be Received Total Lease Expiration Year Lease Expiration Year Operating leases with various expiration dates through year Lessee, Operating Lease, Term of Contract Lease period Contributed Equity Value Contributed Equity Value Contributed equity value Incremental Contribution Value Equity Units Limited Partnership Interest Incremental Contribution Value Equity Units Limited Partnership Interest Incremental closing payments, Limited Partnership interest Preferred Units, Contribution To Obtain Equity Units Preferred Units, Contribution To Obtain Equity Units Contributed amount to obtain equity units Contribution Value Equity Units Limited Partnership Interest Contribution Value Equity Units Limited Partnership Interest Contributed amount to obtain equity units Right Of First Refusal To Invest In Preferred Units, Amount Right Of First Refusal To Invest In Preferred Units, Amount Right of first refusal to invest Annual Return From Cash Flow Operations Annual Return From Cash Flow Operations Annual return Annual Return On The Equity Value, Base Return Annual Return On The Equity Value, Base Return Base return Annual Return On The Equity Value, Capital Base Return Annual Return On The Equity Value, Capital Base Return Capital base return Pro Rata Distribution Percent Pro Rata Distribution Percent Pro rata distribution Internal Rate of Return Percent Internal Rate of Return Percent Internal rate of return Pro Rata Distribution Percent, Cash Flow From Capital Events Pro Rata Distribution Percent, Cash Flow From Capital Events Pro rata share Preferred Unit, Dividend Rate, Percentage Preferred Unit, Dividend Rate, Percentage Preferred unit annual rate Value of the preferred units acquired. Preferred Unit Value Preferred unit in operating partnership Convertible Preferred Unit, Shares Issued Upon Conversion Convertible Preferred Unit, Shares Issued Upon Conversion Convertible preferred units Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Exercisable period Expiration period Conversion Of Stock, Number Of Shares Called By Stocks Conversion Of Stock, Number Of Shares Called By Stocks Shares that may be converted to common units Common Unit Distributions Per Unit Declared Common Unit Distributions Per Unit Declared Common unit distribution per unit declared Distribution declared per common unit Noncontrolling Interest, Estimated Redemption Value Noncontrolling Interest, Estimated Redemption Value Estimated redemption value Invested Capital Invested Capital Invested capital Preferred Units, Purchase Price Preferred Units, Purchase Price Purchase price Preferred Units, Purchase Price, Less Distribution Preferred Units, Purchase Price, Less Distribution Purchase price, less distributions Loan-To-Value Ratio Loan-To-Value Ratio Loan-to-value ratio Line of Credit Facility, Increased Borrowing Capacity Line of Credit Facility, Increased Borrowing Capacity Increased line of credit Equity Capitalization Excess Percent Equity Capitalization Excess Percent Equity capitalization percent Temporary Equity, Stock Issued During Period, Value, New Issues Net Redeemable Noncontrolling Interest Decrease From Distribution Redeemable Noncontrolling Interest Decrease From Distribution Distributions Date Share Repurchase Program was initiated. Date Share Repurchase Program Initiation Date share repurchase program was initiated Stock Repurchase Program Authorized Amount Capacity of share repurchase program Payments for Repurchase of Equity Aggregate cost of stock repurchased Stock Repurchase Program Remaining Authorized Repurchase Amount Capacity available for additional repurchase of outstanding common stock Proceeds from Issuance of Common Limited Partners Units Proceeds from sale of common units Common stock reserved for future issuance Reserved stocks for issuance Monthly cash investment without restriction, maximum. Monthly Cash Investment Without Restriction Maximum Monthly cash investment without restriction, maximum Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2013 Incentive Stock Plan [Member] Two Thousand Thirteen Incentive Stock Plan [Member] 2013 Incentive Stock Plan [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term Weighted average remaining contractual life Share price Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options exercised Stock or Unit Option Plan Expense Stock options expense Share Based Compensation Arrangement By Share-based Payment Award Threshold Share Price Trigger Share Based Compensation Arrangement By Share-based Payment Award Threshold Share Price Trigger Common stock trade share price Share Based Compensation Arrangement By Share-based Payment Award Vesting Installment Term Share Based Compensation Arrangement By Share-based Payment Award Vesting Installment Term Annual installments Share Based Compensation Arrangement By Share-based Payment Award Threshold Trading Days Share Based Compensation Arrangement By Share-based Payment Award Threshold Trading Days Common stock trading days Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Number of shares authorized Shares Issued, Price Per Share Share price issued Share-based Compensation Arrangement by Share-based Payment Award, Options, Shares To Be Vested and Expected to Vest, Exercisable, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Shares To Be Vested and Expected to Vest, Exercisable, Number Shares to be vested and exercisable Income Allocation Equivalent, Percent Income Allocation Equivalent, Percent Income allocation Share-based Compensation Arrangement by Share-based Payment Award, Expiration Date Common stock expiration date Cash Distribution, Percent Cash Distribution, Percent Percent of cash distribution Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Total unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Total unrecognized compensation cost, period of recognition Percentage Of Award Percentage Of Award Percent of the award Percentage Of Units Forfeited Percentage Of Units Forfeited Percentage of units forfeited Remaining Percentage Of The Award Remaining Percentage Of The Award Remaining percent of the award Total Stockholder Return, Percent Total Stockholder Return, Percent TSR percent Common Stock Dividends Per Share Paid Percent, Payable On Common Unit Common Stock Dividends Per Share Paid Percent, Payable On Common Unit Dividends paid, percent representing common unit of limited partnership interest Common Stock Dividends Per Share Paid Percent, Payable Upon Vesting Of Long-Term Investment Plan Unit Common Stock Dividends Per Share Paid Percent, Payable Upon Vesting Of Long-Term Investment Plan Unit Dividends paid, percent payable upon vesting of LTIP Unit Maximum Percentage Of Retainer Fee Directors May Elect To Defer To Stock Units Maximum Percentage Of Retainer Fee Directors May Elect To Defer To Stock Units Maximum percentage of retainer fee that directors may defer Deferred stock units earned. Deferred Stock Units Shares Earned Deferred stock units earned Deferred Stock Units, Converted Deferred Stock Units, Converted Deferred stock units converted Deferred stock units outstanding. Deferred Stock Units Outstanding Deferred stock units outstanding Dividends declared per common share Investment Company, Financial Highlights [Table] Investment Company, Financial Highlights [Line Items] Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest Net income Net income (loss) available to common shareholders Noncontrolling Interest, Redemption Value Adjustment, Redeemable Noncontrolling Interest, Redemption Value Adjustment, Redeemable Add (deduct): Redeemable noncontrolling interests Redeemable noncontrolling interests Minority Interest, Decrease From Noncontrolling Interest Minority Interest, Decrease From Noncontrolling Interest Change in noncontrolling interests in consolidated joint ventures Adjustments to Additional Paid in Capital, Dividends in Excess of Retained Earnings Shares issued under Dividend Reinvestment and Stock Purchase Plan Stock Based Compensation Attributable To Noncontrolling Interest Stock Based Compensation Attributable To Noncontrolling Interest Stock compensation Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (loss) from continuing operations Noncontrolling Interest, Redemption Value Adjustment, Redeemable Before Operating Partnership Noncontrolling Interest, Redemption Value Adjustment, Redeemable Before Operating Partnership Add (deduct): Redemption value adjustment of redeemable noncontrolling interests attributable to common shareholders Income Loss From Continuing Operations Basic Income Loss From Continuing Operations Basic Income (loss) from continuing operations available to common shareholders Income Loss From Discontinued Operations Available To Common Shareholders Income Loss From Discontinued Operations Available To Common Shareholders Income (loss) from discontinued operations available to common shareholders Net Income (Loss) Available to Common Stockholders, Basic Net income (loss) available to common shareholders for basic earnings per share Income (Loss) from Continuing Operations, Diluted Earnings Per Share Income (Loss) from Continuing Operations, Diluted Earnings Per Share Net income (loss) from continuing operations available to common shareholders Noncontrolling Interest Redemption Value Adjustment Redeemable In Operating Partnership Noncontrolling Interest Redemption Value Adjustment Redeemable In Operating Partnership Add (deduct): Redemption value adjustment of redeemable noncontrolling interests in the Operating Partnership unitholders Income Loss From Continuing Operations Diluted Income Loss From Continuing Operations Diluted Income (loss) from continuing operations for diluted earnings per share Net Income (Loss) Available to Common Stockholders, Diluted Net income (loss) available for diluted earnings per share Common units. Common Units Add: Operating Partnership - common and vested LTIP units Future Developments [Member] Future Developments [Member] Future Developments [Member] Number Of Common Shares Received Upon Redemption Of Common Units Number Of Common Shares Received Upon Redemption Of Common Units Number of common shares received upon redemption of common units Rebalance Of Ownership Percentage Rebalance Of Ownership Percentage Rebalance of ownership percentage Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Percentage of noncontrolling interest Distribution of cash flow to individual companies percentage Distribution Of Cash Flow To Individual Companies Percentage Excess net cash flow remaining after the distribution to the Company Proceeds from Sale of Real Estate Proceeds from sale of properties Stock Issued During Period, Value, Long-Term Incentive Plan Units, Forfeited Stock Issued During Period, Value, Long-Term Incentive Plan Units, Forfeited Cancellation of unvested LTIP units Schedule of Segment Reporting Information, by Segment [Table] Geographical [Axis] Segment Geographical [Domain] Geographical [Domain] Foreign Country [Member] Foreign Locations [Member] Number of Reportable Segments Number of business segments Long-Lived Assets Long lived assets Business Segments [Axis] Segment [Domain] Segment [Domain] Real Estate Commercial And Other Segment [Member] Real Estate Commercial And Other Segment [Member] Commercial And Other Real Estate [Member] Multiple-Family Real Estate And Services Segment [Member] Multiple Family Real Estate And Services Segment [Member] Multiple-Family Real Estate & Services [Member] Total operating and interest expenses. Operating And Interest Expenses Total operating and interest expenses Segment Reporting Information, Net Operating Income (Loss) For Reportable Segment Segment Reporting Information, Net Operating Income (Loss) For Reportable Segment Net operating income (loss) Net operating income Long Lived Assets Long Lived Assets Total long-lived assets Legal Entity [Axis] Entity [Domain] Entity [Domain] Mack Cali Realty LP [Member] Mack Cali Realty Lp [Member] Mack-Cali Realty LP [Member] Product and Service [Axis] Products And Services [Domain] Product and Service [Domain] Real Estate Services [Member] Real Estate Services [Member] Real Estate Services [Member] Parking [Member] Parking Income [Member] Hotel [Member] Hotel Income [Member] Real Estate Other [Member] Other Income [Member] Partner Type [Axis] Partner Type Of Partners Capital Account Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] General Partner [Member] General Partner Common Units [Member] Limited Partner [Member] Limited Partner Common Units/Vested LTIP Units [Member] General Partner Common Unitholders [Member] General Partner Common Unitholders [Member] General Partner Common Unitholders [Member] Limited Partners Common Unitholders [Member] Limited Partners Common Unitholders [Member] Limited Partner Common Unitholders [Member] Other Ownership Interest [Member] Noncontrolling Interest In Consolidated Joint Ventures [Member] Accumulated Other Comprehensive Income [Member] Accumulated Other Comprehensive Income (Loss) [Member] Disposal Group Heldforsale Not Discontinued Operations [Member] Disposal Group, Held-for-sale, Not Discontinued Operations [Member] Long-term Debt, Type [Axis] Longterm Debt Type [Domain] Long-term Debt, Type [Domain] Unsecured Debt [Member] Senior Unsecured Notes [Member] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Twenty Seventeen Unsecured Revolving Credit Facility [Member] Twenty Seventeen Unsecured Revolving Credit Facility [Member] 2017 Credit Facility [Member] Unsecured Revolving Credit Facility [Member] Unsecured Revolving Credit Facility [Member] Unsecured Revolving Credit Facility [Member] Twenty Seventeen Term Loan [Member] Twenty Seventeen Term Loan [Member] 2017 Term Loan [Member] Twenty Sixteen Term Loan [Member] Twenty Sixteen Term Loan [Member] 2016 Term Loan [Member] Secured Debt [Member] Secured Debt [Member] Suburban Office Portfolio [Member] Suburban Office Portfolio [Member] Suburban Office Portfolio [Member] Commercial Real Estate [Member] Commercial Properties [Member] Office Building [Member] Office [Member] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Development [Member] Development [Member] Development [Member] Parsippany, New Jersey [Member] Parsippany New Jersey [Member] Parsippany, New Jersey [Member] Parsippany, Madison, Short Hills, Edison, And Red Bank, New Jersey [Member] Parsippany Madison Short Hills Edison And Red Bank New Jersey [Member] Parsippany, Madison, Short Hills, Edison, And Red Bank, New Jersey [Member] Short Hills, New Jersey [Member] Short Hills New Jersey [Member] Short Hills, New Jersey [Member] Disposal Group Not Discontinued Operations [Member] Disposal Group, Not Discontinued Operations [Member] Segment Discontinued Operations [Member] Discontinued Operations [Member] Properties Disposed One [Member] Properties Disposed One [Member] Properties Disposed One [Member] Properties Disposed Two [Member] Properties Disposed Two [Member] Properties Disposed Two [Member] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Upton [Member] Upton [Member] Upton [Member] Construction Loans [Member] Construction Loan [Member] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held For Sale Name [Domain] Long Lived Assets Held-for-sale, Name [Domain] Other Assets Held, Assets Held For Sale [Member] Other Assets Held Assets Held For Sale [Member] Other Assets Held for Sale [Member] One Hundred Overlook Center [Member] One Hundred Overlook Center [Member] 100 Overlook Center [Member] Unconsolidated Joint Venture Other Property [Member] Unconsolidated Joint Venture Other Property [Member] Unconsolidated Joint Venture Other Property [Member] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Parent Company [Member] Parent Company [Member] Variable Interest Entity Primary Beneficiary [Member] Variable Interest Entity, Primary Beneficiary [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Domain] Loss Contingency, Nature [Domain] Guarantee Of Indebtedness Of Others [Member] Guarantee of Indebtedness of Others [Member] PI North Pier Land [Member] Pi North Pier Land [Member] PI North Pier Land [Member] Riverwalk Retail [Member] Riverwalk Retail [Member] Riverwalk Retail [Member] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated As Hedging Instrument [Member] Designated as Hedging Instrument [Member] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] Credit Risk Contract [Member] Credit Risk Contract [Member] Receivable Type [Axis] Receivable Type [Domain] Receivable [Domain] Interest Free Notes Receivable [Member] Interest Free Notes Receivable [Member] Interest-Free Notes Receivable [Member] Seller Financing Receivable [Member] Seller Financing Receivable [Member] Seller Financing Receivable [Member] Interest Rate Swap [Member] Interest Rate Swaps [Member] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Interest Expense [Member] Interest Expense [Member] Disposal Group One [Member] Disposal Group One [Member] Disposal Group One [Member] Four Point Five Zero Zero Percent Senior Unsecured Notes Due April Eighteen Two Thousand Twenty Two [Member] Four Point Five Zero Zero Percent Senior Unsecured Notes Due April Eighteen Two Thousand Twenty Two [Member] 4.500% Senior Unsecured Notes Due April 18, 2022 [Member] 3.150% Senior Unsecured Note, Due May 15, 2023 [Member] Three Point One Five Zero Percent Senior Unsecured Notes Due May Fifteenth Two Thousand Twenty Three [Member] 3.150% Senior Unsecured Notes, Due May 15, 2023 [Member] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] Base Rate [Member] Base Rate [Member] Overnight Bank Funding Rate [Member] Overnight Bank Funding Rate [Member] Overnight Bank Funding Rate [Member] Unsecured Term Loan [Member] Unsecured Term Loan [Member] Unsecured Term Loan [Member] 5.800% Senior Unsecured Notes, due January 15, 2016 Five Point Eight Zero Zero Percent Senior Unsecured Notes Due January Fifteen Two Thousand Sixteen [Member] 5.800% Senior Unsecured Notes, Due January 15, 2016 [Member] Twenty Sixteen Term Loan, Extension One [Member] Twenty Sixteen Term Loan Extension One [Member] 2016 Term Loan, Extension One [Member] Twenty Seventeen Credit Agreement [Member] Twenty Seventeen Credit Agreement [Member] 2017 Credit Agreement [Member] Twenty Seventeen Credit Agreement, Letter Of Credit [Member] Twenty Seventeen Credit Agreement Letter Of Credit [Member] 2017 Credit Agreement, Letter Of Credit [Member] Twenty Seventeen Credit Agreement Amendment And Twenty Sixteen Term Loan Amendment [Member] Twenty Seventeen Credit Agreement Amendment And Twenty Sixteen Term Loan Amendment [Member] 2017 Credit Agreement Amendment And 2016 Term Loan Amendment [Member] Twenty Seventeen Credit Facility, Extension One [Member] Twenty Seventeen Credit Facility Extension One [Member] 2017 Credit Facility, Extension One [Member] Twenty Twenty One Senior Secured Credit Facility [Member] Twenty Twenty One Senior Secured Credit Facility [Member] 2021 Credit Agreement [Member] Twenty Twenty One Credit Agreement [Member] Twenty Twenty One Credit Agreement [Member] 2021 Credit Facility [Member] Twenty Twenty One Term Loan [Member] Twenty Twenty One Term Loan [Member] 2021 Term Loan [Member] Twenty Twenty One Credit Agreement, Letter Of Credit [Member] Twenty Twenty One Credit Agreement Letter Of Credit [Member] 2021 Credit Agreement, Letter Of Credit [Member] Twenty Twenty One Credit Facility, Usage Less Or Equal To Fifty Percent [Member] Twenty Twenty One Credit Facility Usage Less Or Equal To Fifty Percent [Member] 2021 Credit Facility, Usage Less Or Equal To Fifty Percent [Member] Twenty Twenty One Credit Facility, Usage Greater Than Fifty Percent [Member] Twenty Twenty One Credit Facility Usage Greater Than Fifty Percent [Member] 2021 Credit Facility, Usage Greater Than Fifty Percent [Member] Harborside Two Thirds And Harborside Financial Center Plaza 5 [Member] Harborside Two Thirds And Harborside Financial Center Plaza5 [Member] Harborside 2/3 And Harborside 5 [Member] Forty Five Unsecured Term Loan Percent Leverage Ratio [Member] Forty Five Unsecured Term Loan Percent Leverage Ratio [Member] 45% Unsecured Term Loan Leverage Ratio [Member] Forty Five And Fifty Unsecured Term Loan Percent Leverage Ratio [Member] Forty Five And Fifty Unsecured Term Loan Percent Leverage Ratio [Member] 45% And 50% Unsecured Term Loan Leverage Ratio [Member] Fifty And Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member] Fifty And Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member] 50% And 55% (Current ratio) Unsecured Term Loan Leverage Ratio [Member] Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member] Fifty Five Percent Unsecured Term Loan Leverage Ratio [Member] 55% Unsecured Term Loan Leverage Ratio [Member] Credit Rating, Moody's [Axis] External Credit Rating Moodys [Member] External Credit Rating, Moody's [Domain] No Ratings Or Less Than Moodys Baa3 Rating [Member] No Ratings Or Less Than Moodys Baa3 Rating [Member] No Ratings Or Less Than Baa3 [Member] Moodys Baa3 Rating [Member] Baa3 [Member] Moodys Baa2 Rating [Member] Baa2 [Member] Moodys Baa1 Rating [Member] Baa1 [Member] Moody's A3 Rating Or Higher [Member] Moodys A3 Rating Or Higher [Member] A3 Or Higher [Member] Credit Rating, Standard & Poor's [Axis] External Credit Rating Standard Poors [Member] External Credit Rating, Standard & Poor's [Domain] No Ratings Or Less Than Standard Poors BBB [Member] No Ratings Or Less Than Standard Poors B B B Minus [Member] No Ratings Or Less Than BBB- [Member] Standard Poors B B B Minus Rating [Member] BBB- [Member] Standard Poors B B B Rating [Member] BBB [Member] Standard Poors B B B Plus Rating [Member] BBB+ [Member] Standard & Poor's A- Rating Or Higher [Member] Standard Poors Minus Rating Or Higher [Member] A- Or Higher [Member] Forty Five Unsecured 2017 Term Loan Percent Leverage Ratio [Member] Forty Five Unsecured2017 Term Loan Percent Leverage Ratio [Member] 45% Unsecured 2017 Term Loan Leverage Ratio [Member] Forty Five And Fifty Unsecured 2017 Term Loan Percent Leverage Ratio [Member] Forty Five And Fifty Unsecured2017 Term Loan Percent Leverage Ratio [Member] 45% And 50% Unsecured 2017 Term Loan Leverage Ratio [Member] Fifty And Fifty Five Percent Unsecured 2017 Term Loan Leverage Ratio [Member] Fifty And Fifty Five Percent Unsecured2017 Term Loan Leverage Ratio [Member] 50% And 55% (Current ratio) Unsecured 2017 Term Loan Leverage Ratio [Member] Fifty Five Percent Unsecured 2017 Term Loan Leverage Ratio [Member] Fifty Five Percent Unsecured2017 Term Loan Leverage Ratio [Member] 55% Unsecured 2017 Term Loan Leverage Ratio [Member] Forty Five Unsecured 2016 Term Loan Percent Leverage Ratio [Member] Forty Five Unsecured2016 Term Loan Percent Leverage Ratio [Member] 45% Unsecured 2016 Term Loan Leverage Ratio [Member] Forty Five And Fifty Unsecured 2016 Term Loan Percent Leverage Ratio [Member] Forty Five And Fifty Unsecured2016 Term Loan Percent Leverage Ratio [Member] 45% And 50% Unsecured 2016 Term Loan Leverage Ratio [Member] Fifty And Fifty Five Percent Unsecured 2016 Term Loan Leverage Ratio [Member] Fifty And Fifty Five Percent Unsecured2016 Term Loan Leverage Ratio [Member] 50% And 55% (Current ratio) Unsecured 2016 Term Loan Leverage Ratio [Member] Fifty Five Percent Unsecured 2016 Term Loan Leverage Ratio [Member] Fifty Five Percent Unsecured2016 Term Loan Leverage Ratio [Member] 55% Unsecured 2016 Term Loan Leverage Ratio [Member] Related Party [Axis] Related Party [Domain] Related Party [Domain] Corporate Joint Venture [Member] Unconsolidated Joint Venture [Member] Projects Under Development And Developable Land [Member] Projects Under Development And Developable Land [Member] Projects Under Development And Developable Land [Member] Port Imperial 4/5 Retail [Member] Port Imperial Four And Five Retail [Member] Port Imperial South 4/5 Retail [Member] Portside Seven [Member] Portside Seven [Member] Portside 7 [Member] Short Hills Residential [Member] Short Hills Residential [Member] Short Hills Residential [Member] Two Hundred Fifty Johnson Road [Member] Two Hundred Fifty Johnson Road [Member] 250 Johnson Road [Member] Liberty Towers [Member] Liberty Towers [Member] Liberty Towers [Member] The Charlotte [Member] Charlotte [Member] The Charlotte [Member] Portside Five/Six Project [Member] Portside Five Six Project [Member] Portside 5/6 [Member] Marbella [Member] Marbella [Member] Marbella [Member] Marbella II [Member] Marbella Ii [Member] Marbella II [Member] One Hundred One Hudson Street [Member] One Hundred One Hudson Street [Member] 101 Hudson [Member] Worcester [Member] Worcester [Member] Worcester [Member] Short Hills Portfolio [Member] Short Hills Portfolio [Member] Short Hills Portfolio [Member] 150 Main St [Member] One Hundred Fifty Main Street [Member] 150 Main St [Member] Monaco Towers [Member] Monaco Towers [Member] Monaco (BLVD 495 N/S) [Member] Port Imperial South Eleven [Member] Port Imperial South Eleven [Member] Port Imperial South 11 [Member] Soho Lofts Apartments [Member] Soho Lofts Apartments [Member] Soho Lofts [Member] Riverwatch Commons [Member] Riverwatch Commons [Member] Riverwatch Commons [Member] One Hundred Eleven River Street, Hoboken, New Jersey [Member] One Hundred Eleven River Street Hoboken New Jersey [Member] 111 River St. [Member] Port Imperial 4/5 Garage Development [Member] Port Imperial45 Garage Development [Member] Port Imperial 4/5 Garage Development [Member] Retail Property [Member] Retail Property [Member] Retail Property [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy and NAV [Domain] Fair Value Inputs Level3 [Member] Level 3 [Member] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Measurement Input Discount Rate [Member] Measurement Assumptions, Discount Rates [Member] Measurement Input Cap Rate [Member] Measurement Assumptions, Exit Capitalization Rates [Member] Measurement Input, Market Rental Rate [Member] Measurement Input Market Rental Rate [Member] Measurement Assumptions, Market Rental Rates Per Square Foot [Member] Measurement Input, Market Rates Per Square Foot [Member] Measurement Input Market Rates Per Square Foot [Member] Measurement Assumptions, Market Rates Per Square Foot [Member] Port Imperial Hotel Development [Member] Port Imperial Hotel Development [Member] Port Imperial Hotel Development [Member] Port Imperial South Eleven Development [Member] Port Imperial South Eleven Development [Member] Port Imperial South 11 Development [Member] One One One River Realty [Member] One One One River Realty [Member] 111 River Realty [Member] Port Imperial South Park Parcel [Member] Port Imperial South Park Parcel [Member] Port Imperial South Park Parcel [Member] Tax Period [Axis] Tax Period [Domain] Tax Period [Domain] Tax Year One [Member] Tax Year One [Member] Tax Year 1 [Member] Tax Year Two [Member] Tax Year Two [Member] Tax Year 2 [Member] Tax Year Three [Member] Tax Year Three [Member] Tax Year 3 [Member] Tax Year Four [Member] Tax Year Four [Member] Tax Year 4 [Member] Tax Year Five [Member] Tax Year Five [Member] Tax Year 5 [Member] Years One To Four [Member] Years One To Four [Member] Years 1-4 [Member] Years Five To Eight [Member] Years Five To Eight [Member] Years 5-8 [Member] Years Nine To Ten [Member] Years Nine To Ten [Member] Years 9-10 [Member] Years One To Ten [Member] Years One To Ten [Member] Years 1-10 [Member] Years Eleven To Eighteen [Member] Years Eleven To Eighteen [Member] Years 11-18 [Member] Years Nineteen To Twenty-Five [Member] Years Nineteen To Twenty Five [Member] Years 19-25 [Member] Scenario [Axis] Scenario Unspecified [Domain] Scenario, Unspecified [Domain] Scenario Forecast [Member] Scenario, Forecast [Member] Accounting Standards Update [Axis] Type Of Adoption [Member] Accounting Standards Update [Domain] Accounting Standards Update201602 [Member] Accounting Standards Update 2016-02 [Member] Twenty Five Christopher Columbus [Member] Twenty Five Christopher Columbus [Member] 25 Christopher Columbus [Member] Restructuring Type [Axis] Type Of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance [Member] Employee Severance [Member] Title of Individual [Axis] Title Of Individual With Relationship To Entity [Domain] Title of Individual with Relationship to Entity [Domain] Mahbod Nia, Chief Executive Officer [Member] Mahbod Nia Chief Executive Officer [Member] Mahbod Nia, CEO [Member] MAG Partners 2.0 LLC [Member] Mag Partners2.0 Llc [Member] MAG Partners [Member] Bow Street LLC [Member] Bow Street Llc [Member] Bow Street LLC [Member] Award Type [Axis] Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Award Type [Domain] Stay-On Award Agreement [Member] Stay On Award Agreement [Member] Stay-On Award Agreement [Member] Rockpoint Group, L.L.C. [Member] Rockpoint Group L.l.c. [Member] Rockpoint [Member] Roseland Residential Trust [Member] Roseland Residential Trust [Member] RRT [Member] Roseland Residential, L.P. [Member] Roseland Residential L.p. [Member] RRLP [Member] Discretionary Demand Promissory Note [Member] Discretionary Demand Promissory Note [Member] Credit Enhancement Note [Member] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Investment Agreement [Member] Investment Agreement [Member] Investment Agreement [Member] Add On Investment Agreement [Member] Add On Investment Agreement [Member] Add On Investment Agreement [Member] Common Units [Member] Common Units [Member] Common Units [Member] Preferred Units by Name [Axis] Preferred Units Class [Domain] Preferred Units, Class [Domain] Series A Units [Member] Series Units [Member] Series A Units [Member] Series A-One Preferred Limited Partnership Units [Member] Series One Preferred Limited Partnership Units [Member] Series A-1 Units [Member] Preferred Units [Member] Preferred Units [Member] Preferred Units [Member] Cash Flow From Operations [Member] Cash Flow From Operations [Member] Cash Flow From Operations [Member] Cash Flow From Capital Events, Distribution Three [Member] Cash Flow From Capital Events Distribution Three [Member] Cash Flow From Capital Events, Distribution Three [Member] Cash Flow From Capital Events, Distribution Four [Member] Cash Flow From Capital Events Distribution Four [Member] Cash Flow From Capital Events, Distribution Four [Member] Cash Flow From Capital Events, Distribution Five [Member] Cash Flow From Capital Events Distribution Five [Member] Cash Flow From Capital Events, Distribution Five [Member] Cash Flow From Capital Events, Distribution Six [Member] Cash Flow From Capital Events Distribution Six [Member] Cash Flow From Capital Events, Distribution Six [Member] Distribution One [Member] Distribution One [Member] Distribution One [Member] Distribution Two [Member] Distribution Two [Member] Distribution Two [Member] Redeemable Noncontrolling Interests [Member] Redeemable Noncontrolling Interests [Member] Redeemable Noncontrolling Interests [Member] Series A Units & Series A-One Preferred Limited Partnership Units [Member] Series Units Series One Preferred Limited Partnership Units [Member] Series A And Series A-1 Preferred Units In MCRLP [Member] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Dividend Reinvestment And Stock Purchase Plan [Member] Dividend Reinvestment And Stock Purchase Plan [Member] Dividend Reinvestment And Stock Purchase Plan [Member] Vesting [Axis] Vesting [Domain] Vesting [Domain] Three Equal Annual Installment [Member] Three Equal Annual Installment [Member] Three Equal Annual Installment [Member] Common Stock Trades [Member] Common Stock Trades [Member] Common Stock Trades [Member] Class of Stock [Axis] Class Of Stock [Domain] Class of Stock [Domain] Common Class At $14.39 [Member] Common Class At14.39 [Member] Common Class At $14.39 [Member] Common Class At $20.00 [Member] Common Class At20.00 [Member] Common Class At $20.00 [Member] AO LTIP Units Award [Member] Ao Ltip Units Award [Member] AO LTIP Units Award [Member] Michael J. DeMarco, Chief Executive Officer [Member] Michael J. Demarco Chief Executive Officer [Member] Messr DeMarco, CEO [Member] Share Based Compensation Award Tranche One [Member] Tranche One [Member] Share Based Compensation Award Tranche Two [Member] Tranche Two [Member] Share Based Compensation Award Tranche Three [Member] Tranche Three [Member] Other Executive Officers [Member] Other Executive Officers [Member] Other Executive Officers [Member] Messieur DeMarco And Messieur Tycher [Member] Messieur Demarco And Messieur Tycher [Member] Messieur DeMarco And Messieur Tycher [Member] Messieur Tycher, Smetana, Wagner, Cardoso, And Hilton [Member] Messieur Tycher Smetana Wagner Cardoso And Hilton [Member] Messieur Tycher, Smetana, Wagner, Cardoso, And Hilton [Member] Messieur DeBari [Member] Messieur Debari [Member] Messr DeBari [Member] Ricardo Cardoso [Member] Ricardo Cardoso [Member] Ricardo Cardoso [Member] Two Thousand Sixteen Long-Term Incentive Plan [Member] Two Thousand Sixteen Long Term Incentive Plan [Member] 2016 LTIP Awards [Member] Unvested Long-Term Incentive Plan [Member] Unvested Long Term Incentive Plan [Member] Unvested LTIP [Member] Two Thousand Eighteen Long-Term Incentive Plan [Member] Two Thousand Eighteen Long Term Incentive Plan [Member] 2018 LTIP Awards [Member] Two Thousand Eighteen Outperformance Plan [Member] Two Thousand Eighteen Outperformance Plan [Member] 2018 OPP [Member] Two Thousand Nineteen Long-Term Incentive Plan [Member] Two Thousand Nineteen Long Term Incentive Plan [Member] 2019 LTIP Awards [Member] Two Thousand Nineteen Time-Based Vesting Long-Term Incentive Plan [Member] Two Thousand Nineteen Time Based Vesting Long Term Incentive Plan [Member] 2019 TBV LTIP Units [Member] Two Thousand Nineteen Outperformance Plan [Member] Two Thousand Nineteen Outperformance Plan [Member] 2019 OPP [Member] Two Thousand Twenty Outperformance Plan [Member] Two Thousand Twenty Outperformance Plan [Member] 2020 OPP [Member] J Series 2021 OPP [Member] J Series2021 Opp [Member] J Series 2021 OPP [Member] Twenty Twenty One RSU LTIP Awards [Member] Twenty Twenty One Rsu Ltip Awards [Member] 2021 RSU LTIP Awards [Member] Outperformance RSUs [Member] Outperformance Rsus [Member] Outperformance RSUs [Member] Time-Based Award [Member] Time Based Award [Member] Time-Based Award [Member] Performance Shares [Member] Performance Shares [Member] Ownership [Axis] Ownership [Domain] Ownership [Domain] Flex Properties [Member] Flex Properties [Member] Flex Portfolio [Member] Asset Class [Axis] Fair Value Assets Measured On Recurring Basis Unobservable Input Reconciliation By Asset Class [Domain] Asset Class [Domain] Participation Rights [Member] Participation Rights [Member] Participation Rights [Member] Corporate And Other [Member] Corporate & Other [Member]