Condensed Consolidated Balance Sheets (Unaudited) Condensed Consolidated Balance Sheets (Unaudited) [Abstract] Class of Stock [Domain] Assets: Assets: [Abstract] Operating real estate, net of accumulated depreciation of $1,745,992 and $1,693,090, respectively Investments and advances in real estate joint ventures Real estate under development Other real estate investments Mortgages and other financing receivables Cash and cash equivalents Marketable securities Accounts and notes receivable Other assets Total assets Liabilities: Liabilities: [Abstract] Notes payable Mortgages payable Construction loans payable Dividends payable Other liabilities Total liabilities Redeemable noncontrolling interests Stockholders' equity: Stockholders' equity: [Abstract] Preferred Stock, Value Common Stock, $.01 par value, authorized 750,000,000 shares issued and outstanding 407,608,794 and 406,937,830 shares, respectively Paid-in capital Cumulative distributions in excess of net income Total stockholders' equity excluding accumulated other comprehensive income Accumulated other comprehensive income Total stockholders' equity Noncontrolling interests Total equity Total liabilities and equity Operating real estate, accumulated depreciation (in Dollars) Preferred Stock, Par Value (in Dollars per share) Preferred Stock, Shares Authorized (in Shares) Preferred Stock, Shares Issued (in Shares) Preferred Stock, Shares Outstanding (in Shares) Preferred Stock, Aggregate Liquidation Preference (in Dollars) Common Stock, Par Value (in Dollars per share) Common Stock, Shares Authorized (in Shares) Common Stock, Shares Issued (in Shares) Common Stock, Shares Outstanding (in Shares) Condensed Consolidated Statements of Income (Unaudited) Condensed Consolidated Statements of Income (Unaudited) [Abstract] Equity Method Investee, Name [Domain] Segment, Operating Activities [Domain] Revenues Revenues [Abstract] Revenues from rental property Management and other fee income Total revenues Operating expenses Operating expenses [Abstract] Rent Real estate taxes Operating and maintenance General and administrative expenses Impairment charges Depreciation and amortization Total operating expenses Operating income Other income/(expense) Other income/(expense) [Abstract] Mortgage and other financing income Interest, dividends and other investment income Other expense, net Interest expense Income from other real estate investments. Income from other real estate investments Income from continuing operations before income taxes, equity in income of joint ventures and equity in income from other real estate investments Provision for income taxes, net Equity in income of investment Income from continuing operations Discontinued operations Discontinued operations [Abstract] Income/(loss) from discontinued operating properties, net of tax Impairment/loss on operating properties sold, net of tax Gain on disposition of operating properties, net of tax Income from discontinued operations Gain on sale of operating properties, net of tax Net income Net income attributable to noncontrolling interests Net income attributable to the Company Redemption costs Preferred stock dividends Net income available to the Company's common shareholders Per common share: Per common share: [Abstract] Income from continuing operations: Income from continuing operations: [Abstract] -Basic (in Dollars per share) -Diluted (in Dollars per share) Net income: Net income: [Abstract] -Basic (in Dollars per share) -Diluted (in Dollars per share) Weighted average shares: Weighted average shares: [Abstract] -Basic (in Shares) -Diluted (in Shares) Amounts available to the Company's common shareholders: Amounts available to the Company's common shareholders: [Abstract] Income from continuing operations, net of tax Income from discontinued operations Net income Condensed Consolidated Statements of Comprehensive Income (Unaudited) Condensed Consolidated Statements of Comprehensive Income (Unaudited) [Abstract] Derivative, Name [Domain] Net income Other comprehensive income: Other comprehensive income: [Abstract] Change in unrealized gain/(loss) on marketable securities Change in unrealized gain on interest rate swaps Foreign currency translation adjustment Other comprehensive income Comprehensive income Comprehensive income attributable to noncontrolling interests Comprehensive income attributable to the Company Condensed Consolidated Statements of Changes in Equity (Unaudited) Condensed Consolidated Statements of Changes in Equity (Unaudited) [Abstract] Equity Component [Domain] Balance Balance (in Shares) Contributions from noncontrolling interests Comprehensive income: Comprehensive income: [Abstract] Net income Other comprehensive income, net of tax: Other comprehensive income, net of tax: [Abstract] Unrealized gain (loss) on marketable securities Change in foreign currency translation adjustment Comprehensive income Comprehensive income [Abstract] Redeemable noncontrolling interests Dividends Distributions to noncontrolling interests Issuance of stock Issuance of stock (in Shares) Surrender of common stock Surrender of common stock (in Shares) Repurchase of common stock Repurchase of common stock (in Shares) Exercise of common stock options Exercise of common stock options (in Shares) Acquisition of noncontrolling interests Amortization of equity awards Balance Balance (in Shares) Redemption of preferred stock Redemption of preferred stock (in Shares) Dividends, per common share (in Dollars per share) Dividends, per Depositary share (in Dollars per share) Condensed Consolidated Statements of Cash Flows (Unaudited) Condensed Consolidated Statements of Cash Flows (Unaudited) [Abstract] Cash flow from operating activities: Cash flow from operating activities: [Abstract] Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to reconcile net income to net cash provided by operating activities: [Abstract] Depreciation and amortization Gain on sale or transfer of operating properties. Gain on sale of operating properties Equity in income of joint ventures, net Equity in income from other real estate investments, net Distributions from joint ventures and other real estate investments Cash retained from excess tax benefits Change in accounts and notes receivable Change in accounts payable and accrued expenses Change in other operating assets and liabilities Net cash flow provided by operating activities Cash flow from investing activities: Cash flow from investing activities: [Abstract] Acquisition of and improvements to operating real estate Acquisition of and improvements to real estate under development Proceeds from sale/repayments of marketable securities Investments and advances to real estate joint ventures Reimbursements of investments and advances to real estate joint ventures Other real estate investments Reimbursements of investments and advances to other real estate investments Investment in mortgage loans receivable Collection of mortgage loans receivable Other investments Reimbursements of other investments Proceeds from sale of operating properties Proceeds from sale of development properties Net cash flow (used for) provided by investing activities Cash flow from financing activities: Cash flow from financing activities: [Abstract] Principal payments on debt, excluding normal amortization of rental property debt Principal payments on rental property debt Principal payments on construction loan financings Proceeds from mortgage/construction loan financings (Repayment) proceeds under unsecured revolving credit facilities, net Proceeds from issuance of unsecured term loan Repayment of unsecured notes Financing origination costs Redemption of non-controlling interests Dividends paid Cash retained from excess tax benefits Proceeds from issuance of stock Redemption of preferred stock Repurchase of common stock Net cash flow provided by (used for) financing activities Change in cash and cash equivalents Cash and cash equivalents, beginning of year Cash and cash equivalents, end of year Interest paid during the year (net of capitalized interest of $1,273 and $6,142, respectively) Income taxes paid during the year Cash paid for capitalized interest (in Dollars) Note 1 - Interim Financial Statements Significant Accounting Policies [Text Block] Note 2 - Operating Property Activities