Subsequent Events [Abstract] Subsequent Event [Table] Subsequent Event [Table] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Escondido Promenade Escondido Promenade [Member] Former Mervyns Parcel, Escondido Promenade [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Notes payable Notes Payable, Other Payables [Member] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Municipal bonds repaid Municipal Debt Securities, at Carrying Value Accounting Policies [Abstract] Supplemental disclosures related to the Consolidated Statements Of Cash Flows Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Nature Of Operations [Abstract] Nature Of Operations [Abstract] Number of real estate properties Number of Real Estate Properties Minimum percentage of taxable income distributed to shareholders Minimum Percentage Of Taxable Income Distributed To Shareholders Minimum percentage of taxable income distributed to shareholders. Commitments and Contingencies Disclosure [Abstract] COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Stockholders' Equity Note [Abstract] Summary of dividends declared and paid per share Dividends Declared [Table Text Block] Components Of Rental Income and Expense [Abstract] Components Of Rental Income And Expense [Abstract] Components of Rental Income [Table] Components of Rental Income [Table] Components of Rental Income [Table] Property Subject to or Available for Operating Lease 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] Retail and Commercial Commercial Real Estate [Member] Residential Residential Real Estate [Member] Statement [Line Items] Statement [Line Items] 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 Operating Leases, Income Statement, Lease Revenue SUBSEQUENT EVENTS Subsequent Events [Text Block] Earnings Per Share [Abstract] Statement [Table] Statement [Table] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] INCOME FROM CONTINUING OPERATIONS Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Less: Preferred share dividends Preferred Stock Dividends, Income Statement Impact Less: Net income attributable to noncontrolling interests Net income attributable to noncontrolling interests, net of amounts from gain on real estate Net income attributable to noncontrolling interests, net of amounts from gain on real estate 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. Gain on change in control of interests and sale of real estate, net Gain (loss) on change in control of interests and sale of real estate, net Gain (loss) on change in control of interests and sale of real estate, net of noncontrolling interests 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 Dilutive Effect of Share-based Payment Arrangements Weighted average common shares outstanding—diluted Weighted Average Number of Shares Outstanding, Diluted Continuing operations Income (Loss) from Continuing Operations, Per Basic Share Gain on sale of real estate and change in control of interests, net Gain (loss) on change in control of interests and sale of real estate, net, per basic share Gain (loss) on change in control of interests and sale of real estate, net, per basic share Earnings per common share, basic Earnings Per Share, Basic Continuing operations Income (Loss) from Continuing Operations, Per Diluted Share Gain on sale of real estate and change in control of interests, net Gain (loss) on change in control of interests and sale of real estate, net, per diluted share Gain (loss) on change in control of interests and sale of real estate, net, per diluted share Earnings per common share, diluted Earnings Per Share, Diluted Income from continuing operations attributable to the Trust Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Real Estate [Abstract] REAL ESTATE Real Estate Acquisitions Dispositions Text Block Disclosure of real estate acquisitions and dispositions, and at year end, a summary of our real estate investments and related encumbrances. Schedule of Minimum Rents [Table] Schedule of Minimum Rents [Table] Schedule of Minimum Rents [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Amortization of above market leases Above Market Leases [Member] Amortization of below market leases BelowMarketLease [Member] BelowMarketLease [Member] Minimum Rent [Line Items] Minimum Rent [Line Items] Minimum Rent [Line Items] Straight-line rents Straight Line Rent Amortization of above and below market leases Amortization of above and below Market Leases Principles of Consolidation Consolidation, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Recently Issued Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Recently Adopted Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Text Block] 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. New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Adjustments for New Accounting Pronouncement Adjustments for New Accounting Pronouncement [Member] Variable Interest Entities [Axis] Variable Interest Entities [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Previous voting interest entity Previous voting interest entity [Member] Previous voting interest entity prior to adoption of ASU. Pike and Rose Hotel JV Pike and Rose Hotel JV [Member] Pike and Rose Hotel JV New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Number of variable interest entities previously consolidated as voting interest entities Number of Properties Previously Consolidated as Voting Interest Entities Number of variable interest entity properties that were previously consolidated as voting interest entities prior to the adoption of ASU 2015-02, "Amendments to the Consolidation Analysis." Net real estate assets of VIEs previously consolidated as voting interest entities Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net Mortgages payable of VIEs previously consolidated as voting interest entities Mortgage Payable From Consolidated Variable Interest Entities Mortgages payable balances from variable interest entities, or VIEs, for the periods presented. Investment in variable interest entity Variable Interest Entity, Nonconsolidated, Carrying Amount, Assets Maximum exposure to loss in variable interest entity Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount Unamortized Debt Issuance Costs Unamortized Debt Issuance Expense Schedule of earnings per share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Earnings Per Share Narrative [Table] Earnings Per Share Narrative [Table] Earnings Per Share Narrative [Table] 5.417% Series 1 Cumulative Convertible Preferred shares 5.417% Series 1 Cumulative Convertible Preferred [Member] Five point Four One Seven Percentage Series One Cumulative Convertible Preferred Stock [Member] Earnings Per Share Narrative [Line Items] Earnings Per Share Narrative [Line Items] Earnings Per Share Narrative [Line Items] Weighted average unvested shares outstanding Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights Anti-dilutive stock options Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Cumulative convertible preferred shares, dividend rate Preferred Stock, Dividend Rate, Percentage Statement of Stockholders' Equity [Abstract] Net income attributable to redeemable noncontrolling interests Net Income (Loss) Attributable to Redeemable Noncontrolling Interest Dividends [Table] Dividends [Table] Dividends [Table] Common shares Common Stock [Member] Dividends [Line Items] Dividends [Line Items] [Line Items] for Dividends [Table] Series 1 Cumulative Convertible Preferred Shares Interest Rate Dividends declared per common share Common Stock, Dividends, Per Share, Declared Dividends paid per common share Common Stock, Dividends, Per Share, Cash Paid Dividends declared per preferred share Preferred Stock, Dividends Per Share, Declared Dividends paid per preferred share Preferred Stock, Dividends, Per Share, Cash Paid Fair Value Disclosures [Abstract] FAIR VALUE OF FINANCIAL INSTRUMENTS Fair Value Disclosures [Text Block] Schedule of Significant Acquisitions [Table] Schedule of Business Acquisitions, by Acquisition [Table] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] Federal Realty Investment Trust/Clarion Partners Partnership Federal Realty Investment Trust / ING Clarion Partners Partnership [Member] Federal Realty Investment Trust / ING Clarion Partners Partnership [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Federal Realty Investment Trust Federal Realty Investment Trust [Member] Federal Realty Investment Trust [Member] Clarion Clarion [Member] Clarion [Member] A building in Coconut Grove, Florida CocoWalk [Member] CocoWalk Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] General and Administrative Expense General and Administrative Expense [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Other Assets Other Assets [Member] Other Liabilities Other Liabilities [Member] Asset Class [Axis] Asset Class [Axis] Asset Class [Domain] Asset Class [Domain] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] An additional building in the Coconut Grove neighborhood of Miami, Florida An additional building in the Coconut Grove neighborhood of Miami, Florida [Member] An additional building in the Coconut Grove neighborhood of Miami, Florida [Member] Significant Acquisitions [Line Items] Business Acquisition [Line Items] Ownership Percentage in partnership Equity Method Investment, Ownership Percentage Purchase price Business Combination, Consideration Transferred Cash paid in acquisition Payments to Acquire Businesses, Gross Mortgage loans assumed with acquisition Noncash or Part Noncash Acquisition, Debt Assumed Gain on change in control of interests Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain Other assets acquired for above market leases Finite-lived Intangible Assets Acquired Other assets acquired for below market leases Below Market Lease, Acquired Acquisition costs incurred Business Combination, Acquisition Related Costs Our share of the gain on sale, net of noncontrolling interests Gain (loss) on sale of real estate, net of noncontrolling interests Our share of gain (loss) on sale of real estate, net of noncontrolling interests SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Significant Accounting Policies [Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Derivative Instrument Derivative Instrument [Axis] Derivative, Name [Domain] Derivative Contract [Domain] Interest Rate Swap Interest Rate Swap [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair value of interest rate swaps Derivative Liability Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Share-based Compensation, Allocation and Classification in Financial Statements [Abstract] Grants of shares and options 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 downREIT operating partnership units, outstanding Partners' Capital Account, Units downREIT operating partnership units outstanding, fair value Operating Partnership Units Fair Value Fair value of operating partnership units at the balance sheet date. Valuation and Qualifying Accounts Disclosure [Table] Valuation and Qualifying Accounts Disclosure [Table] Gain on sale of real estate and change in control of interests gain on sale of real estate [Member] gain on sale of real estate [Member] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves Type [Axis] Valuation Allowances and Reserves [Domain] Valuation Allowances and Reserves [Domain] Warranty reserve Warranty Reserves [Member] Name of Property [Axis] Name of Property [Axis] Name of Property [Domain] Name of Property [Domain] Galaxy/Hollywood Galaxy/Hollywood [Member] Galaxy/Hollywood [Member] Santana Row Santana Row [Member] Santana Row Valuation and Qualifying Accounts Disclosure [Line Items] Valuation and Qualifying Accounts Disclosure [Line Items] Released latent defect warranty on condominiums sold Valuation Allowances and Reserves, Deductions Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest, by Legal Entity [Table] Redeemable Noncontrolling Interest [Line Items] Redeemable Noncontrolling Interest [Line Items] Noncontrolling interest percent acquired Percentage of noncontrolling interest acquired Percentage of noncontrolling interest acquired Redemption price of noncontrolling interest Payments for Repurchase of Redeemable Noncontrolling Interest Effective Interest Acquisition Ownership interest Ownership interest in property Income Statement [Abstract] REVENUE Revenues [Abstract] Rental income Other property income Other Real Estate Revenue Mortgage interest income Revenue Mortgage Interest Interest income earned from mortgage notes receivable. Total revenue Revenues 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 Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Total operating expenses Operating Expenses OPERATING INCOME Operating Income (Loss) Other interest income Interest Income, Other Interest expense Interest Expense Early extinguishment of debt Gain (Loss) on Extinguishment of Debt Income from real estate partnerships Income (Loss) from Equity Method Investments INCOME FROM CONTINUING OPERATIONS Gain on sale of real estate and change in control of interests Gain (loss) on change in control of interests and sale of real estate Gain (loss) on change in control of interests and sale of real estate NET INCOME Net Income (Loss), Including Portion Attributable to Noncontrolling Interest 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 NET INCOME AVAILABLE FOR COMMON SHAREHOLDERS Net Income (Loss) Available to Common Stockholders, Basic EARNINGS PER COMMON SHARE, BASIC Earnings Per Share, Basic [Abstract] Earnings per common share, basic Weighted average number of common shares, basic EARNINGS PER COMMON SHARE, DILUTED Earnings Per Share, Diluted [Abstract] Earnings per common share, diluted Weighted average number of common shares, diluted COMPREHENSIVE INCOME Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest COMPREHENSIVE INCOME ATTRIBUTABLE TO THE TRUST Comprehensive Income (Loss), Net of Tax, Attributable to Parent Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Operating (including $1,219,223 and $1,192,336 of consolidated variable interest entities, respectively) Rental Properties Construction-in-progress Construction in Progress, Gross Real estate, at cost, total Real Estate Investment Property, at Cost Less accumulated depreciation and amortization (including $200,877 and $176,057 of consolidated variable interest entities, respectively) Real Estate Investment Property, Accumulated Depreciation Net real estate Real Estate Investment Property, Net Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value 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 Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Prepaid expenses and other assets Prepaid Expense and Other Assets TOTAL ASSETS Assets Liabilities Liabilities [Abstract] Mortgages payable (including $441,294 and $448,315 of consolidated variable interest entities, respectively) Secured Debt 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 Deferred Credits and Other Liabilities Total liabilities Liabilities Commitments and contingencies (Note 6) Commitments and Contingencies Redeemable noncontrolling interests Redeemable Noncontrolling Interest, Equity, Carrying Amount 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, 71,782,989 and 69,493,392 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 Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total shareholders’ equity of the Trust Stockholders' Equity Attributable to Parent Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Total shareholders’ equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY Liabilities and Equity Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities [Member] Term loan TermLoan [Member] TermLoan [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Number of interest rate swap agreements Number of Interest Rate Derivatives Held Notional amount of interest rate swap agreements Derivative Liability, Notional Amount Term Loan Other Notes Payable Interest rate of variable portion of Term loan Derivative, Fixed Interest Rate Interest rate cash flow hedge to be reclassified within next 12 months, net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Other comprehensive income (loss) - change in value of interest rate swaps Other Comprehensive Income (Loss), Net of Tax Interest expense reclassified from other comprehensive loss Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net Summary of share-based compensation expense included in net income Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] EARNINGS PER SHARE Earnings Per Share [Text Block] Statement, Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Preferred Shares Preferred Stock [Member] Additional Paid-in Capital Additional Paid-in Capital [Member] Accumulated Dividends in Excess of Net Income Accumulated Distributions in Excess of Net Income [Member] Accumulated Other Comprehensive Loss AOCI Attributable to Parent [Member] Noncontrolling Interests Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance (in shares) Shares, Outstanding Beginning balance Net income, excluding $2,133 attributable to redeemable noncontrolling interests Profit Loss Excluding Redeemable Noncontrolling Interests Net income (loss) excluding portion attributable to redeemable noncontrolling interests. Other comprehensive loss - change in value of interest rate swaps 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) Stock Issued During Period, Shares, New Issues 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 of forfeitures (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 of forfeitures 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). Shares withheld for employee taxes (in shares) Shares Paid for Tax Withholding for Share Based Compensation Shares withheld for employee taxes Shares withheld for employee taxes net value Shares withheld for employee taxes net value Conversion and redemption of OP units (in shares) Conversion and Redemption of Operating Partnership Units in Shares Number of shares issued during the period as a result of the conversion and redemption of operating partnership units into shares 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. Contributions from noncontrolling interests Noncontrolling Interest, Increase from Business Combination Adjustment to redeemable noncontrolling interests Stockholders' Equity, Other Ending balance (in shares) Ending balance Mortgages Payable And Notes Payable Mortgages Payable And Notes Payable [Member] Mortgages Payable And Notes Payable [Member] Senior Notes And Debentures Senior Notes And Debentures [Member] Senior Notes And Debentures [Member] Measurement Basis [Axis] Measurement Basis [Axis] Fair Value Measurement [Domain] Fair Value Measurement [Domain] Portion at Fair Value Measurement [Member] Portion at Fair Value Measurement [Member] Carrying Value Reported Value Measurement [Member] Fair Value Estimate of Fair Value Measurement [Member] Fair value of long-term debt Long-term Debt, Fair Value SHARE-BASED COMPENSATION PLANS Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Operating real estate, 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. Accumulated depreciation and amortization, consolidated variable interest entities Accumulated depreciation and amortization, consolidated variable interest entities Accumulated depreciation and amortization related to real estate, Consolidated Variable Interest Entities. Mortgages payable, consolidated variable interest entities Preferred shares, authorized Preferred Stock, Shares Authorized Preferred shares, par value Preferred Stock, Par or Stated Value Per Share 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 value 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 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 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 and change in control of interests 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 in accounts receivable Increase (Decrease) in Accounts and Other Receivables Increase in prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Increase (decrease) in accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities (Decrease) increase 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 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 repayments under revolving credit facility, net of costs Proceeds from (Repayments of) Lines of Credit Issuance of senior notes, net of costs Proceeds from Issuance of Senior Long-term Debt Redemption and retirement of senior notes Repayments of Senior Debt Repayment of mortgages, capital leases and notes and other payables Repayments of Long-term Debt, Long-term Capital Lease Obligations, and Capital Securities Issuance of common shares, net of costs Proceeds from Issuance of Common Stock 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 and redemptions of noncontrolling interests PaymentsOfDividendsAndRedemptionsMinorityInterest The cash outflow for the return on capital for noncontrolled interest in the entity and cash outflow during the period for redemptions of noncontrolling interests. Redemption of redeemable noncontrolling interests Net cash provided by (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 Principal components of rental income Schedule of Component of Rental Income [Table Text Block] Schedule of Component of Rental Income [Table Text Block] Minimum rents Schedule Of Minimum Rents Components [Table TextBlock] Schedule of Minimum Rents Components [Table Text Block] 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] Summary of financial liabilities measured at fair value on a recurring basis Fair Value, Liabilities Measured on Recurring Basis [Table Text Block] Total interest costs incurred Interest Costs Incurred Interest capitalized Interest Costs Capitalized Interest expense Cash paid for interest, net of amounts capitalized (1) Interest Paid, Net Cash paid for income taxes Income Taxes Paid, Net DownREIT operating partnership units redeemed for common shares Redemptionofoperatingpartnershipunitsforcommonshares Redemption of operating partnership units for common shares DownREIT operating partnership units issued with acquisition ValueofdownREITOperatingPartnershipUnitsIssuedinConnectionwithBusinessAcqu Value of downREIT Operating Partnership Units Issued in Connection with Business Acquisition Shares issued under dividend reinvestment plan Dividends Reinvested in Noncash Financing Transaction Dividends reinvested in noncash financing transaction Prepayment premium on senior note Payments of Debt Extinguishment Costs SHAREHOLDERS’ EQUITY Stockholders' Equity Note Disclosure [Text Block] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Sale of Stock [Axis] Sale of Stock [Axis] Sale of Stock [Domain] Sale of Stock [Domain] At The Market Equity Program At The Market Equity Program [Member] At The Market Equity Program [Member] Public Equity Offering Public Equity Offering [Member] Public Equity Offering Stock Issuance Costs by Type [Axis] Stock Issuance Costs by Type [Axis] Stock Issuance Costs by Type [Axis] Stock Issuance Costs by Type [Domain] Stock Issuance Costs by Type [Domain] [Domain] for Stock Issuance Costs by Type [Axis] Commissions Commissions [Member] Commissions [Member] Other Offering Costs Other Offering Costs [Member] Other Offering Costs [Member] Class of Stock [Line Items] Class of Stock [Line Items] Aggregate Offering Price Of Common Share Aggregate Offering Price Of Common Share Maximum aggregate offering price of common shares. Common shares issued Weighted Average Price Per Common Share Weighted Average Price Per Common Share Weighted average price per common share Proceeds from Issuance of Common Stock Payments of Stock Issuance Costs (less than for additional offering expenses for the three months ending June 30, 2016) Payments of Stock Issuance Costs Remaining Capacity To Issue Remaining Capacity To Issue Remaining $ Capacity Of Shares To Issue Price per share Shares Issued, Price Per Share Document And Entity Information [Abstract] Document and Entity Information Abstract 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 Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding BUSINESS AND ORGANIZATION Nature of Operations [Text Block] Debt Instruments [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] 3.625% Senior notes 3.625% Senior notes [Member] 3.625% Senior notes [Member] Line of Credit Line of Credit [Member] Mortgages Mortgages [Member] Senior notes Senior Notes [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Principal Fair value Debt Instrument, Fair Value Disclosure Weighted Average Interest Rate Debt, Weighted Average Interest Rate Maximum borrowing capacity under revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Interest rate basis spread over LIBOR Debt Instrument, Basis Spread on Variable Rate Line of credit facility, option to increase amount Line of credit facility, option to increase amount Option to increase credit facility under accordian feature, in dollars. Principal amount Long-term Debt, Gross Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Note offering percent Note Offering Percent Note offering percent of principal amount Debt yield to maturity percent Debt Yield To Maturity Percent Debt yield to maturity percent Net proceeds from issuance of senior notes Maximum amount outstanding under revolving credit facility Line of Credit Facility, Maximum Amount Outstanding During Period Weighted average interest rate, before amortization of debt fees LineofCreditFacilityWeightedAverageInterestRateBeforeAmortizationOfDebt Fees Line of credit facility weighted average interest rate, before amortization of debt fees. Weighted average borrowings outstanding Line of Credit Facility, Average Outstanding Amount DEBT Debt Disclosure [Text Block]