Equity Method Investments and Joint Ventures [Abstract] Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Legal Entity [Axis] Entity [Domain] Taurus Investment Holdings [Member] Taurus Investment Holdings, LLC [Member] Federal Realty Investment Trust [Member] Federal Realty Investment Trust [Member] Clarion [Member] Clarion [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Loan Secured By Two Buildings [Member] Loan Secured By Two Buildings [Member] Loan Secured By Two Buildings [Member] Schedule of Equity Method Investment, Equity Method Investee, Name [Axis] Schedule of Equity Method Investment, Equity Method Investee, Name [Axis] Equity Method Investee, Name [Domain] Newbury Street Partnership [Member] Newbury Street Partnership [Member] Taurus Newbury Street JV II Limited Partnership [Member] Federal / Lion Venture LP [Member] Federal / Lion Venture LP [Member] Statement [Line Items] Statement [Line Items] Number of properties secured by loans Number Of Real Estate Properties Secured The number of properties securing loans. Ownership interest in partnership Equity Method Investment, Ownership Percentage Date of Acquisition of Newbury Partnership Property Business Acquisition, Effective Date of Acquisition Total number of properties in the portfolio Number of Real Estate Properties Acquisition of real estate Business Acquisition Purchase Price The purchase price of the acquired entity. Leasable area (square feet) Square Footage of Real Estate Property Contributed towards acquisition of property Payments to Acquire Equity Method Investments Our investment in real estate partnership Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Secured loan Secured Debt F R T Carrying value as of the balance sheet date of collateralized debt obligations for which we are the lender. Debt Instrument, Maturity Date Loan interest rate Debt Instrument, Interest Rate Terms Buy-sell date Buy-Sell Date The date that the buy-sell provision can be exercised under certain circumstances. Extension Option Period Extension Option Period Extension Option Period Basis Points Spread Over LIBOR Basis Points Spread The number of basis points added to LIBOR to compute the total interest rate. Income (Loss) from Equity Method Investments Income (Loss) from Equity Method Investments Discontinued Operations and Disposal Groups [Abstract] Summary Of The Financial Information For The Discontinued Operations Schedule Of Discontinued Operations Financial Information Table Text Block Schedule Of Discontinued Operations Financial Information Table Text Block Stockholders' Equity Note [Abstract] Stockholders' Equity [Table] Stockholders' Equity [Table] Stockholders' Equity [Table] Subsidiary, Sale of Stock [Axis] Subsidiary, Sale of Stock [Axis] Sale of Stock, Name of Transaction [Domain] Sale of Stock, Name of Transaction [Domain] At The Market Equity Program [Member] At The Market Equity Program [Member] At The Market Equity Program [Member] Aggregate offering price of common share Aggregate Offering Price Of Common Share Maximum aggregate offering price of common shares. Shares issued under equity program Stock Issued During Period, Shares, New Issues Weighted average price per common share Weighted Average Price Per Common Share Weighted average price per common share Net cash proceeds of common stock Proceeds from Issuance of Common Stock Commissions related to sales of common shares Payments of Stock Issuance Costs Accounting Policies [Abstract] Summary Of Significant Accounting Policies Significant Accounting Policies [Text Block] Commitments and Contingencies Disclosure [Abstract] Final judgment related to a previously disclosed lawsuit Litigation Settlement, Gross Operating partnership units, outstanding Partners' Capital Account, Units Operating partnership units outstanding, fair value Operating Partnership Units Fair Value Fair value of operating partnership units at the balance sheet date. Earnings Per Share [Abstract] Statement [Table] Range [Axis] Range [Domain] LessThan [Member] LessThan [Member] Weighted average unvested shares outstanding Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights Anti-dilutive stock options excluded from dilutive earnings per share calculation Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Cumulative convertible preferred share, dividend rate Preferred Stock, Dividend Rate, Percentage Schedule Of Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Fair Value Disclosures [Abstract] Fair Value Of Financial Instruments Fair Value Disclosures [Text Block] Revenue from discontinued operations Disposal Group, Including Discontinued Operation, Revenue Income from discontinued operations Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax Subsequent Events [Abstract] Subsequent Events [Text Block] Subsequent Events [Text Block] Real Estate Partnerships Equity Method Investments Disclosure [Text Block] Equity Method Investee, Name [Domain] Federal / Lion Venture LP [Member] Revenue Revenues Other operating expenses Operating Costs and Expenses Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Interest expense Interest Expense Total expenses Total Expenses Total expenses including operating expenses, interest expense, depreciation and amortization, and other expenses. NET INCOME Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Income from real estate partnerships Real estate, net Real Estate Investment Property, Net Cash Cash and Cash Equivalents, at Carrying Value Other assets Other Assets TOTAL ASSETS Assets Mortgages payable Secured Debt Other liabilities Other Liabilities Partners' capital Partners' Capital TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity Our share of unconsolidated debt Share Of Unconsolidated Debt Share Of Unconsolidated Debt Schedule Of Supplemental Disclosures Related To Consolidated Statements Of Cash Flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Commitments And Contingencies Commitments and Contingencies Disclosure [Text Block] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Shares [Member] Common Stock [Member] 5.417% Series 1 Cumulative Convertible Preferred [Member] 5.417% Series 1 Cumulative Convertible Preferred [Member] Five point Four One Seven Percentage Series One Cumulative Convertible Preferred Stock [Member] Dividend declared, common share Common Stock, Dividends, Per Share, Declared Dividend paid, common share Common Stock, Dividends, Per Share, Cash Paid Dividend declared, preferred share Preferred Stock, Dividends Per Share, Declared Dividend paid, preferred share Preferred Stock, Dividends, Per Share, Cash Paid Preferred Stock, Dividend Rate, Percentage Real Estate Investments [Abstract] Real Estate Real Estate Acquisitions Dispositions Discontinued Operations Text Block Disclosure of real estate acquisitions, dispositions and discontinued operations and at year end, a summary of our real estate investments and related encumbrances. Statement of Stockholders' Equity [Abstract] Statement [Table] Statement, Equity Components [Axis] Statement, Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Preferred Shares [Member] Preferred Stock [Member] Additional Paid-in Capital [Member] Additional Paid-in Capital [Member] Accumulated Dividends in Excess of Net Income [Member] Accumulated Distributions in Excess of Net Income [Member] Noncontrolling Interests [Member] Noncontrolling Interest [Member] Beginning balance (in shares) Shares, Outstanding Beginning balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Net income/Comprehensive income Dividends declared to common shareholders Dividends, Common Stock, Cash Dividends declared to preferred shareholders Dividends, Preferred Stock, Cash Distributions declared to noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Common shares issued (in shares) Common shares issued Stock Issued During Period, Value, New Issues Exercise of stock options (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Exercise of stock options Stock Issued During Period, Value, Stock Options Exercised Shares issued under dividend reinvestment plan (in shares) Stock Issued During Period, Shares, Dividend Reinvestment Plan Shares issued under dividend reinvestment plan Stock Issued During Period, Value, Dividend Reinvestment Plan Share-based compensation expense, net (in shares) Share Based Compensation Expense Net Shares Number of shares issued during the period as a result of our long term incentive, bonus or other share based compensation plans, net of restricted share award forfeitures. Share-based compensation expense, net Share Based Compensation Expense Net Value This element represents the amount of recognized equity-based compensation related to other long-term incentive and bonus plans during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized). Conversion and redemption of OP units Conversion And Redemption Of Operating Partnership Units Decrease in noncontrolling interest as a result of redeeming, purchasing and/or converting to common stock the interests of Operating Partnership Units. Purchase of noncontrolling interest Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests Deconsolidation of VIE Noncontrolling Interest, Decrease from Deconsolidation Ending balance (in shares) Ending balance Summary Of Carrying Amount And Fair Value Of Financial Instruments Schedule of Carrying Amount and Fair Value of Financial Instruments [Table Text Block] Schedule of Carrying Amount and Fair Value of Financial Instruments [Table Text Block] Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Stock Options [Member] Restricted Stock [Member] Share-based compensation incurred Allocated Share-based Compensation Expense Capitalized share-based compensation Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount Share-based compensation expense Share-based Compensation Nature Of Operations [Abstract] Nature Of Operations [Abstract] Nature of Operations [Text Block] Minimum Percentage Of Taxable Income Distributed To Shareholders Minimum percentage of taxable income distributed to shareholders. Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Operating (including $68,930 and $78,846 of consolidated variable interest entities, respectively) Rental Properties Construction-in-progress Construction in Progress, Gross Assets held for sale/disposal (discontinued operations) (including $0 and $18,311 of consolidated variable interest entities, respectively) Real Estate Held-for-sale Real Estate Investment Property, At Cost, Total Real Estate Investment Property, at Cost Less accumulated depreciation and amortization (including $4,727 and $4,431 of consolidated variable interest entities, respectively) Real Estate Investment Property, Accumulated Depreciation Net real estate Cash and cash equivalents Accounts and notes receivable, net Accounts and Notes Receivable, Net Mortgage notes receivable, net Mortgage Loans on Real Estate, Commercial and Consumer, Net Investment in real estate partnerships Prepaid expenses and other assets Prepaid Expense and Other Assets Debt issuance costs, net of accumulated amortization of $8,384 and $9,075, respectively Deferred Finance Costs, Net Liabilities Liabilities [Abstract] Mortgages payable (including $22,287 and $22,785 of consolidated variable interest entities, respectively) Capital lease obligations Capital Lease Obligations Notes payable Notes Payable Senior notes and debentures Senior Notes Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities Dividends payable Dividends Payable Security deposits payable Security Deposit Liability Other liabilities and deferred credits Other liabilities and deferred credits Other liabilities & deferred credits which includes deferred revenue, prepaid rent and below market leases. Also includes liabilities not individually reported in the financial statements, or not separately disclosed in notes. Total liabilities Liabilities Commitments and contingencies (Note 8) Commitments and Contingencies Shareholders' equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Preferred shares, authorized 15,000,000 shares, $.01 par: 5.417% Series 1 Cumulative Convertible Preferred Shares, (stated at liquidation preference $25 per share), 399,896 shares issued and outstanding Preferred Stock, Value, Issued Common shares of beneficial interest, $.01 par, 100,000,000 shares authorized, 63,494,277 and 61,526,418 shares issued and outstanding, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Accumulated dividends in excess of net income Accumulated Distributions in Excess of Net Income Total shareholders' equity of the Trust Stockholders' Equity Attributable to Parent Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Total shareholders' equity Share-Based Compensation Plans Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Total interest costs incurred Interest Costs Incurred Interest capitalized Interest Costs, Capitalized During Period Interest expense Cash paid for interest, net of amounts capitalized Interest Paid, Net Cash paid for income taxes Income Taxes Paid, Net Mortgage loan assumed with acquisition Loans Assumed Deconsolidation of VIE NonCash Deconsolidation Of Variable Interest Entity Non-cash investing amount related to the deconsoliation of a variable interest entity. Capital lease obligations Capital Lease Obligations Incurred Mortgage Notes Receivable [Abstract] Mortgage Notes Receivable Disclosure [Abstract] Mortgage Loans on Real Estate, Description, Type of Property [Axis] Mortgage Loans on Real Estate, Name, Property Type [Domain] Mortgage loan on a shopping center and an adjacent commercial building in Norwalk ,CT [Member] Mortgage loan on a shopping center and an adjacent commercial building in Norwalk ,CT [Member] Mortgage loan carrying balance he carrying amount of the oustanding balance due under the mortgage loan prior to refinancing. Principal balance of first mortgage loan Mortgage Loans on Real Estate, Face Amount of Mortgages Interest rate of first mortgage loan Mortgage Loans on Real Estate, Interest Rate Maturity date of first mortgage loan Mortgage Loans on Real Estate, Final Maturity Date Cash received as part of refinancing Mortgage Loan On Real Estate Refinancing Payment The amount of cash received at refinancing of a mortgage note receivable related to a previously consolidated VIE. Mortgage Loan Fair Value Mortgage Loan Fair Value The original fair value of the mortgage loan receivable. Discontinued operations - gain on deconsolidation of VIE Discontinued Operation Gain On Deconsolidation Of Variable Interest Entity Gain resulting from the deconsolidation of a variable interest entity Mortgage Loans on Real Estate, Carrying Amount of Mortgages Mortgage Loans on Real Estate, Carrying Amount of Mortgages Income Statement [Abstract] REVENUE Revenues [Abstract] Rental income Rental income The total amount of rental revenue recognized for the period from real estate operations, including minimum rent, straight-line rent, percentage rent and tenant reimbursements. Other property income Other Real Estate Revenue Mortgage interest income Revenue Mortgage Interest Interest income earned from mortgage notes receivable. Total revenue EXPENSES Operating Expenses [Abstract] Rental expenses Direct Costs of Leased and Rented Property or Equipment Real estate taxes Real Estate Tax Expense General and administrative General and Administrative Expense Total operating expenses Operating Expenses OPERATING INCOME Operating Income (Loss) Other interest income Investment Income, Interest Interest expense Early extinguishment of debt Gains (Losses) on Extinguishment of Debt INCOME FROM CONTINUING OPERATIONS Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest DISCONTINUED OPERATIONS Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Discontinued operations - income Discontinued operation - gain on sale of real estate Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Results from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest INCOME BEFORE GAIN ON SALE OF REAL ESTATE Income (Loss) before Gain or Loss on Sale of Properties, and Extraordinary Items Gain on sale of real estate Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest NET INCOME ATTRIBUTABLE TO THE TRUST Net Income (Loss) Attributable to Parent Dividends on preferred shares Preferred Stock Dividends, Income Statement Impact NET INCOME AVAILABLE FOR COMMON SHAREHOLDERS Net Income (Loss) Available to Common Stockholders, Basic EARNINGS PER COMMON SHARE, BASIC Earnings Per Share, Basic [Abstract] Continuing operations Income (Loss) from Continuing Operations, Per Basic Share Discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share Gain on sale of real estate Gain on Sale of Real Estate per Basic Share Gain On Sale Of Real Estate Per Basic Share. Earnings Per Share, Basic, Total Earnings Per Share, Basic EARNINGS PER COMMON SHARE, DILUTED Earnings Per Share, Diluted [Abstract] Continuing operations Income (Loss) from Continuing Operations, Per Diluted Share Discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share Gain on sale of real estate Gain on Sale of Real Estate per Diluted Share Gain On Sale Of Real Estate Per Diluted Share. Earnings Per Share, Diluted, Total Earnings Per Share, Diluted Income from continuing operations Less: Dividends on preferred shares Less: Income from continuing operations attributable to noncontrolling interests Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest Less: Earnings allocated to unvested shares Earnings Allocated To Unvested Shares Earnings allocated to unvested shares Income from continuing operations available for common shareholders Income Loss From Continuing Operations Available For Common Shareholders This element represents the income or loss from continuing operations attributable to the parent after earnings allocated to unvested shares and adjustments for dividends on preferred stock. Results from discontinued operations attributable to the Trust Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Net income available for common shareholders, basic and diluted Net income available for common shareholders, basic and diluted Net income after adjustments for dividends on preferred stock and earnings allocated to unvested shares. Weighted average common shares outstanding-basic Weighted Average Number of Shares Outstanding, Basic Stock options Incremental Common Shares Attributable to Share-based Payment Arrangements Weighted average common shares outstanding-diluted Weighted Average Number of Shares Outstanding, Diluted Income from continuing operations attributable to the Trust Income (Loss) from Continuing Operations Attributable to Parent Principles of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Acquisition Of Real Estate Business Combinations Policy [Policy Text Block] Debt Instruments [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Mortgage Loans on Real Estate, Description, Type of Property [Axis] Mortgage Loans on Real Estate, Name, Property Type [Domain] Tower Shops January 19 2011 [Member] Tower Shops 1/19/11 [Member] Federal Plaza [Member] Federal Plaza [Member] Federal Plaza [Member] Tyson Station [Member] Tyson Station [Member] Tyson Station [Member] 4.5%SeniorNotes [Member] 4.5%SeniorNotes [Member] Line of Credit Facility [Axis] Line of Credit Facility, Lender [Domain] Existing Revolving Credit Facility [Member] Existing Revolving Credit Facility [Member] New Revolving Credit Facility [Member] New Revolving Credit Facility [Member] Mortgage loan face amount Debt Instrument, Face Amount Mortgage loan fair value Debt Instrument, Fair Value Disclosure Mortgage loan interest rate Debt Instrument, Interest Rate, Stated Percentage Percentage of prepayment premium on mortgage loan Percentage of Prepayment Premium on Mortgage Loan Percentage of Prepayment Premium on Mortgage Loan Repayment of mortgage loan Repayments of Secured Debt Prepayment premium on mortgage loan Prepayment Premium On Mortgage Loan Prepayment Premium on Mortgage Loan. Income from early extinguishment of debt Unamortized debt premium Debt Instrument Unamortized Premium WriteOff The amount of unamortized debt premium that was written off due to the early repayment of debt. Unsecured revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Repayment of senior notes Repayments of Senior Debt Revolving credit facility, maximum outstanding Line of Credit Facility, Maximum Amount Outstanding During Period Line of credit facility, weighted average amount outstanding Line of Credit Facility, Average Outstanding Amount Line of credit facility weighted average interest rate before amortization of debt fees Line of credit facility weighted average interest rate before amortization of debt fees Line of credit facility weighted average interest rate, before amortization of debt fees Line of credit facility, amount outstanding Line of Credit Facility, Amount Outstanding Debt Instrument, Interest Rate Terms Line of Credit Facility, Expiration Date Summarized Operating Results And Financial Position Of Partnership Schedule Of Balance Sheets and Operating Results Of Unconsolidated Joint Ventures [Table Text Block] Schedule Of Balance Sheets and Operating Results Of Unconsolidated Joint Ventures [Table Text Block] Summary Of Share Based Compensation Expense Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Components Of Rental Income and Expense [Abstract] Components Of Rental Income And Expense [Abstract] Components Of Rental Income Operating Leases Revenue And Expense Text Block The principal components of rental income and/or rental expense recognized for the period. Schedule Of Principal Components Of Rental Income Schedule of Component of Rental Income [Table Text Block] Schedule of Component of Rental Income [Table Text Block] Schedule of Minimum Rents Components Schedule Of Minimum Rents Components [Table TextBlock] Schedule of Minimum Rents Components [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Tower Shops 1/19/11 [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] Feasterville Shopping Center 7/12/11 [Member] Feasterville Shopping Center July 17 2011 [Member] Feasterville Shopping Center 7/12/11 [Member] Business Acquisition Section 1031 Agreement End Date Month, date and year in which the reverse Section 1031 like-kind exchange agreement ended. Date of acquisition and consolidation Purchase price of leasehold property Acres of real estate property Acres of Real Estate Property Acres of Real Estate Property Purchase price allocation, other assets Business Acquisition, Purchase Price Allocation, Amortizable Intangible Assets Purchase price allocation, liabilities Business Acquisition Purchase Price Allocation Amortizable Intangible Below Market Lease Liabilities The amount of acquisition cost of a business combination allocated to below market lease liabilities that will be amortized. Acquisition costs Business Combination, Acquisition Related Costs Maximum period of sale to defer gain on sale of other property, days Maximum Period On Sale Of Properties To Defer Gains Maximum period on sale of properties to defer gains. Proceeds from sale of buildings Sales of Real Estate Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Statement of Cash Flows [Abstract] OPERATING ACTIVITIES Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Adjustments to reconcile net income to net cash provided by operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization, including discontinued operations Adjustment Depreciation And Amortization The cash flow addback for the non-cash expense of depreciation and amortization including depreciation and amortization related to discontinued operations. Gain on sale of real estate Gain (Loss) on Sale of Properties Gain on deconsolidation of VIE Early extinguishment of debt Income from real estate partnerships Other, net Other Noncash Income (Expense) Changes in assets and liabilities, net of effects of acquisitions and dispositions Increase (Decrease) in Operating Capital [Abstract] (Increase) decrease in accounts receivable Increase (Decrease) in Accounts and Other Receivables Decrease (increase) in prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Decrease in accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Decrease in security deposits and other liabilities Increase Decrease In Security Deposits And Other Liabilities The net change in Security Deposits And Other Liabilities which includes security deposits, deferred revenue and prepaid rent. Also includes liabilities not individually reported in the financial statements, or not separately disclosed in notes. Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities INVESTING ACTIVITIES Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisition of real estate Payments to Acquire Real Estate Capital expenditures - development and redevelopment Capital Expenditures Development Redevelopment Payments to develop or redevelop real estate assets is the process of adding improvements on or to a parcel of land. Such improvements may include drainage, utilities, subdividing, access, buildings, and any combination of these elements. In addition, the cash outflow from construction costs to date on capital projects that have not been completed and assets being constructed that are not ready to be placed into service. Capital expenditures - other Payments for Capital Improvements Proceeds from sale of real estate Proceeds from Sale of Real Estate Held-for-investment Investment in real estate partnerships Payments to Acquire Interest in Subsidiaries and Affiliates Distribution from real estate partnership in excess of earnings Proceeds from Distributions Received from Real Estate Partnerships Leasing costs Increase (Decrease) in Lease Acquisition Costs Repayment (issuance) of mortgage and other notes receivable, net Issuance And Repayments Of Mortgage And Other Notes Receivable Net The cash outflow from the issuance and purchase of receivables arising from the mortgage note on real estate and other notes receivable, net of repayments. Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities FINANCING ACTIVITIES Net Cash Provided by (Used in) Financing Activities [Abstract] Net borrowings under revolving credit facility, net of costs Proceeds From Repayments Of Credit Facility The net cash inflow (outflow) from a contractual arrangement with the lender, including letter of credit, standby letter of credit and revolving credit arrangements, under which borrowings can be made up to a specific amount at any point in time with either short term or long term maturity net of costs incurred. Issuance of senior notes, net of costs Proceeds from Issuance of Senior Long-term Debt Purchase and retirement of senior notes Issuance of mortgages, capital leases and notes payable, net of costs Proceeds from Issuance of Long-term Debt and Capital Securities, Net Repayment of mortgages, capital leases and notes payable Repayments of Long-term Debt, Long-term Capital Lease Obligations, and Capital Securities Issuance of common shares Dividends paid to common and preferred shareholders Dividends Paid To Common And Preferred Shareholders The cash outflow from distribution of an entity's earnings to common and preferred stockholders. Distributions to noncontrolling interests Payments of Dividends, Noncontrolling Interest Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of year Cash and cash equivalents at end of period Components of Rental Income [Table] Components of Rental Income [Table] Components of Rental Income [Table] Products and Services [Axis] Products and Services [Domain] Commercial Real Estate [Member] Residential Real Estate [Member] Minimum rents Operating Leases, Income Statement, Minimum Lease Revenue Cost reimbursement Tenant Reimbursements Percentage rent Operating Leases, Income Statement, Percentage Revenue Other Other Rental Income This element represents other rental revenue earned during the period. Total rental income Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Discontinued Operation or Asset Disposal [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Number of Real Estate Properties Sales of Real Estate Repayment Of Secured Debt FRT Repayment Of Secured Debt FRT Repayment of collateralized debt obligations for which we are the lender Payments for (Proceeds from) Real Estate Partnership Investment, Net Payments for (Proceeds from) Real Estate Partnership Investment, Net Subsequent Event, Date Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Summary Of Dividends Declared And Paid Per Share Schedule of Dividends Declared and Paid Per Share [Table Text Block] Schedule of Dividends Declared and Paid Per Share [Table Text Block] Mortgage Notes Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair Value, Disclosure Item Amounts [Domain] Carrying (Reported) Amount, Fair Value Disclosure [Member] Estimate of Fair Value, Fair Value Disclosure [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Mortgages and notes payable, carrying value Mortgages and Notes Payable Mortgages and Notes Payable Senior notes and debentures, carrying value Mortgages and notes payable, fair value Mortgages and Notes Payable, Fair Value Disclosure Mortgages and Notes Payable, Fair Value Disclosure Senior notes and debentures, fair value Senior Notes and Debentures, Fair Value Disclosure Senior Notes and Debentures, Fair Value Disclosure Shareholders' Equity Stockholders' Equity Note Disclosure [Text Block] Earnings Per Share Earnings Per Share [Text Block] Straight-line Rents Straight Line Rent This element represents the adjustment made to recognize base rents on a straight line basis from when the tenant controls the space through the term of the related lease, net of valuation adjustments. Amortization of above market leases Amortization of Acquired Intangible Assets Amortization of below market leases Amortization Of Acquired Below Market Leases This element represents the amortization of acquired below market lease liabilities over the related lease term. The amortization is reflected as additional rental income from below market leases. Debt Debt Disclosure [Text Block] Consolidated Balance Sheets (Parenthetical) [Abstract] Consolidated Balance Sheets (Parenthetical) [Abstract] Statement, Scenario [Axis] Statement, Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Operating, consolidated variable interest entities Operating Real Estate From Consolidated Variable Interest Entities Operating real estate balances from variable interest entities, or VIEs, for the periods presented. Assets held for sale/disposal (discontinued operations), consolidated variable interest entities Assets Held For Disposal From Consolidated Variable Interest Entities Assets held for disposal balances from variable interest entities, or VIEs, for the periods presented. Accumulated depreciation and amortization, consolidated variable interest entities Accumulated depreciation and amortization, consolidated variable interest entities Accumulated Depreciation And Amortization, Consolidated Variable Interest Entities. Debt issuance costs, accumulated amortization Accumulated Amortization, Deferred Finance Costs Mortgages payable, consolidated variable interest entities Mortgage Payable From Consolidated Variable Interest Entities Mortgages payable balances from variable interest entities, or VIEs, for the periods presented. Preferred shares, authorized Preferred Stock, Shares Authorized Preferred shares, par Preferred Stock, Par or Stated Value Per Share Preferred Shares, percentage Preferred Shares, 5.417% Series 1 Cumulative Convertible liquidation preference Preferred Stock, Liquidation Preference Per Share Preferred shares, shares issued Preferred Stock, Shares Issued Preferred shares, shares outstanding Preferred Stock, Shares Outstanding Common shares of beneficial interest, par Common Stock, Par or Stated Value Per Share Common shares of beneficial interest, shares authorized Common Stock, Shares Authorized Common shares of beneficial interest, shares issued Common Stock, Shares, Issued Common shares of beneficial interest, shares outstanding Common Stock, Shares, Outstanding Document And Entity Information [Abstract] Document and Entity Information Abstract Entities [Table] Entities [Table] Legal Entity [Axis] Entity [Domain] Entity Information [Line Items] Entity Information [Line Items] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding