Grants to Trustees [Abstract] Grants to Trustees [Abstract] Grants To Trustees Trustee Incentive Shares [Text Block] Trustee Incentive Shares [Text Block] The disclosure for trustee compensation-related costs for equity-based compensation, which may include disclosure of policies, compensation plan details, allocation of equity compensation, incentive distributions, equity-based arrangements to obtain goods and services, deferred compensation arrangements, employee stock ownership plan details and employee stock purchase plan details. Balance Sheet Parenthetical [Abstract] Balance Sheet Parenthetical [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common Stock [Member] Common Class A [Member] Common Class A [Member] Common Class B [Member] Common Class B [Member] Statement [Line Items] Statement [Line Items] Partners' Capital: Partners' Capital [Abstract] General partners' capital account, units outstanding (in shares) General Partners' Capital Account, Units Outstanding Limited partners' capital account, units outstanding (in shares) Limited Partners' Capital Account, Units Outstanding Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Employee Incentive Share Plan Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Paradise Plaza [Member] Paradise Plaza [Member] Paradise Plaza [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Prime Rate Less Two Point Zero Zero Percent Due 2017 [Member] Prime Rate Less Two Point Zero Zero Percent Due 2017 [Member] Prime Rate Less Two Point Zero Zero Percent Due 2017 [Member] LIBOR Plus Two Point Seven Five Percent to Three Point Seven Five Percent Unsecured Line of Credit Due 2015 [Member] LIBOR Plus Two Point Seven Five Percent to Three Point Seven Five Percent Unsecured Line of Credit Due 2015 [Member] LIBOR Plus Two Point Seven Five Percent to Three Point Seven Five Percent Unsecured Line of Credit Due 2015 [Member] Debt Maturing in June 2013 [Member] Debt Maturing in June 2013 [Member] Debt Maturing in June 2013 [Member] Debt Maturing in October 2013 [Member] Debt Maturing in October 2013 [Member] Debt Maturing in October 2013 [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum [Member] Minimum [Member] Maximum [Member] Maximum [Member] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Floating Rate Notes [Member] Floating Rate Notes [Member] Floating Rate Notes [Member] Unsecured Line of Credit [Member] Unsecured Line of Credit [Member] Unsecured Line of Credit [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Secured debt Secured Debt Number of collateralized properties (in collateralized properties) Number of Collateralized Properties Number of Collateralized Properties Carrying value of collateralized properties Carrying Value of Collateralized Properties Carrying Value of Collateralized Properties Face amount of debt Debt Instrument, Face Amount Credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Credit facility, amount outstanding Line of Credit Facility, Amount Outstanding Credit facility, remaining borrowing capacity Line of Credit Facility, Remaining Borrowing Capacity Description of variable rate basis Debt Instrument, Description of Variable Rate Basis Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Imputed interest rate Debt Instrument, Imputed Interest Rate Debt Instrument, Imputed Interest Rate Debt discount Debt Instrument, Unamortized Discount Notes payable Notes Payable Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Interim Financial Statements Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Fixed Rate Notes [Member] Fixed Rate Notes [Member] Fixed Rate Notes [Member] Five Point Zero Zero Percent Note Due 2012 [Member] Five Point Zero Zero Percent Note Due 2012 [Member] Five Point Zero Zero Percent Note Due 2012 [Member] Five Point Six Nine Five Percent Note Due 2013 [Member] Five Point Six Nine Five Percent Note Due 2013 [Member] Five Point Six Nine Five Percent Note Due 2013 [Member] Six Point Zero Zero Percent Note Due 2021 [Member] Six Point Zero Zero Percent Note Due 2021 [Member] Six Point Zero Zero Percent Note Due 2021 [Member] Six Point Zero Four Percent Note Due 2014 [Member] Six Point Zero Four Percent Note Due 2014 [Member] Six Point Zero Four Percent Note Due 2014 [Member] Six Point Five Zero Percent Note Due 2014 [Member] Six Point Five Zero Percent Note Due 2014 [Member] Six Point Five Zero Percent Note Due 2014 [Member] Six Point Five Two Percent Note Due 2015 [Member] Six Point Five Two Percent Note Due 2015 [Member] Six Point Five Two Percent Note Due 2015 [Member] Six Point Five Three Percent Notes Due 2013 [Member] Six Point Five Three Percent Notes Due 2013 [Member] Six Point Five Three Percent Notes Due 2013 [Member] Six Point Five Six Percent Note Due 2013 [Member] Six Point Five Six Percent Note Due 2013 [Member] Six Point Five Six Percent Note Due 2013 [Member] Six Point Six Three Percent Notes Due 2014 [Member] Six Point Six Three Percent Notes Due 2014 [Member] Six Point Six Three Percent Notes Due 2014 [Member] Two Point Nine Seven Percent Notes Due 2012 [Member] Two Point Nine Seven Percent Notes Due 2012 [Member] Two Point Nine Seven Percent Notes Due 2012 [Member] LIBOR Plus Two Point Eight Six Percent Note Due 2013 [Member] LIBOR Plus Two Point Eight Six Percent Note Due 2013 [Member] LIBOR Plus Two Point Eight Six Percent Note Due 2013 [Member] Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Term of balloon note after interest rate reset Term of Balloon Note Post Interest Rate Reset Term of Balloon Note Post Interest Rate Reset Term of amortization on balloon note after interest rate reset Term of Amortization on Balloon Note After Interest Rate Reset Term of Amortization on Balloon Note After Interest Rate Reset Schedule of Debt Schedule of Debt [Table Text Block] Schedule of Maturities of Debt Schedule of Maturities of Long-term Debt [Table Text Block] Real Estate [Abstract] Real Estate Disclosure Real Estate Disclosure [Text Block] Cash Flow Parenthetical [Abstract] Cash Flow Parenthetical [Abstract] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Parent [Member] Parent [Member] Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid Cash paid for taxes Income Taxes Paid Non cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Disposal of fully depreciated real estate Disposal of fully depreciated real estate Cost basis for non-cash disposals of fully depreciated real estate assets including building and tenant improvements during the reporting period. Financed insurance premiums Dollar amount of insurance premiums financed during reporting period Amount of insurance premiums financed during the period Value of shares issued under distribution reinvestment plan Stock Issued Accrued offering costs Accrued Offering Costs, Change Dollar amount of the change in costs accrued for offering expenses for the period reported. Acquired interest rate swap Non Cash Investing and FInancing, Aquired Interest Rate Swap Non Cash Investing and FInancing, Aquired Interest Rate Swap Debt discount on acquired note payable Non Cash Investing and FInancing, Debt Discount on Acquired Note Payable Non Cash Investing and FInancing, Debt Discount on Acquired Note Payable Value of Class B shares exchanged for OP units Stock Issued During Period, Value, Conversion of Units Change in fair value of available-for-sale securities Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Change in fair value of cash flow hedge Non Cash Investing and FInancing, Change in Fair Value of Cash Flow Hedge Non Cash Investing and FInancing, Change in Fair Value of Cash Flow Hedge Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other Expense [Member] Other Expense [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Restricted Stock [Member] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] OP Units [Member] OP Units [Member] OP Units [Member] Unvested Restricted Shares [Member] Unvested Restricted Shares [Member] Unvested Restricted Shares [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] OP units excluded from diluted earnings per share because their effect would be anti-dilutive Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Distributions to holders of certain restricted common shares Dividends, Share-based Compensation Distributions to holders of certain restricted common shares charged against earnings Allocated Share-based Compensation Expense Numerator: Numerator: [Abstract] Numerator: [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Distributions paid on unvested restricted shares Distributions Paid on Unvested Restricted Shares Distributions Paid on Unvested Restricted Shares Undistributed earnings attributable to unvested restricted shares Undistributed Earnings Allocated to Participating Securities Net income attributable to unitholders excluding amounts attributable to unvested restricted shares Net Income Attributable to Common Shareholders Excluding Amounts Attributable to Unvested Restricted Shares Net Income Attributable to Common Shareholders Excluding Amounts Attributable to Unvested Restricted Shares Denominator: Denominator: [Abstract] Denominator: [Abstract] Weighted average number of units - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Effect of dilutive securities: Dilutive Securities, Effect on Basic Earnings Per Share [Abstract] Unvested restricted shares (in shares) Incremental Common Shares Attributable to Share-based Payment Arrangements Weighted average number of units - dilutive (in shares) Weighted Average Number of Shares Outstanding, Diluted Earnings Per Unit: Earnings Per Share, Basic and Diluted [Abstract] Basic: Earnings Per Share, Diluted [Abstract] Net income attributable to unitholders excluding amounts attributable to unvested restricted shares Earnings Per Share, Diluted Diluted: Earnings Per Share, Basic [Abstract] Net income attributable to unitholders excluding amounts attributable to unvested restricted shares Earnings Per Share, Basic Segment Reporting [Abstract] Segment Information Segment Reporting Disclosure [Text Block] Schedule of Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Investments, Debt and Equity Securities [Abstract] Schedule of Available-for-Sale Securities Marketable Securities [Table Text Block] Consolidated Balance Sheets [Abstract] Consolidated Balance Sheets [Abstract] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] ASSETS Assets [Abstract] Real estate assets, at cost Real Estate Investment Property, at Cost [Abstract] Property Real Estate Investment Property, at Cost Accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Total real estate assets Total real estate assets Total real estate assets includes i) the net book value of real estate property held for investment purposes and ii) the carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity. Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Marketable securities Available-for-sale Securities Escrows and acquisition deposits Deposits Assets Accrued rents and accounts receivable, net of allowance for doubtful accounts Accounts Receivable, Net Unamortized lease commissions and loan costs Unamortized Lease Commissions and Loan Costs, Net For an unclassified balance sheet, this element represents unamortized lease commissions and loan costs. Unamortized lease commissions are the carrying amount (net of accumulated amortization) as of the balance sheet date of commission costs incurred by the lessor to originate a lease with independent third parties and the lessor's leasing agents that would not have been incurred had that leasing transaction not occurred. Unamortized lease commissions are charged against earnings over the life of the lease. Unamortized loan costs are the carrying amount (net of accumulated amortization) as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Prepaid expenses and other assets Prepaid Expense and Other Assets Total assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Liabilities: Liabilities [Abstract] Accounts payable and accrued expenses Accounts Payable and Accrued Liabilities Tenants' security deposits Security Deposit Liability Dividends and distributions payable Dividends Payable Total liabilities Liabilities Commitments and contingencies: Commitments and Contingencies General Partner, 16,718,796 and 11,317,042 units outstanding as of September 30, 2012 and December 31, 2011, respectively General Partners' Capital Account Limited Partners, 786,191 and 1,360,927 units outstanding as of September 30, 2012 and December 31, 2011, respectively Limited Partners' Capital Account Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax Total partners' capital Partners' Capital Total liabilities and equity Liabilities and Equity Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2008 Long-Term Equity Incentive Ownership Plan [Member] Long-Term Equity Incentive Ownership Plan 2008 [Member] Long-Term Equity Incentive Ownership Plan 2008 [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Shares, Granted, Non-Vested Shares Isused (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Shares Granted, Weighted-Average Grant Date Fair Value, Granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Shares, Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Shares Vested, Total Vest-Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract] Leasing commissions Deferred Costs, Leasing, Gross Deferred financing cost Deferred Finance Costs, Gross Total cost Unamortized Lease Commissions and Loan Costs, Gross Unamortized Lease Commissions and Loan Costs, Gross Less: leasing commissions accumulated amortization Deferred Costs, Leasing, Accumulated Amortization Less: deferred financing cost accumulated amortization Accumulated Amortization, Deferred Finance Costs Total cost, net of accumulated amortization Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Executive Officer [Member] Executive Officer [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Sale of residence, shortfall threshold Executive Relocation, Sale of Residence, Shortfall Threshold Executive Relocation, Sale of Residence, Shortfall Threshold Base for difference calcualtion from which tax payment rate will be calculated Base for Difference Calcualtion From Which Tax Payment Rate Will Be Calculated Base for Difference Calcualtion From Which Tax Payment Rate Will Be Calculated Term of lump sum payment after sale of residence (in days) Term of Lump Sum Payment after Sale of Residence Term of Lump Sum Payment after Sale of Residence Term of payment of housing expenses after sale of residence Term of Payment of Housing Expenses after Sale of Residence Term of Payment of Housing Expenses after Sale of Residence Stockholders' Equity Note [Abstract] Schedule of Distributions Schedule of Distributions Made to Members or Limited Partners, by Distribution [Table Text Block] Unamortized Leasing Comissions and Loan Costs Other Deferred Costs Disclosures Income Tax Disclosure [Abstract] Income Taxes [Table] Income Taxes [Table] Income Taxes [Table] Income Tax Authority [Axis] Income Tax Authority [Axis] Income Tax Authority [Domain] Income Tax Authority [Domain] Internal Revenue Service (IRS) [Member] Internal Revenue Service (IRS) [Member] State and Local Jurisdiction [Member] State and Local Jurisdiction [Member] Texas [Member] TEXAS Income Taxes [Line Items] Income Taxes [Line Items] Income Taxes [Line Items] Minimum amount of tax penalty Minimum Amount of Tax Penalty Minimum Amount of Tax Penalty Minimum amount of tax penalty, percentage Minimum Amount of Tax Penalty, Percentage Minimum Amount of Tax Penalty, Percentage Tax paid as a result of violation of 5% asset test Tax Paid As A Result of Violation of Five Percent Asset Test Tax Paid As A Result of Violation of Five Percent Asset Test Applicable tax rate used to determine state margin tax Applicable Tax Rate Used to Determine State Margin Tax Applicable Tax Rate Used to Determine State Margin Tax Standard deduction rate used to determine state margin tax Standard Deduction Rate Used to Determine State Margin Tax Standard Deduction Rate Used to Determine State Margin Tax Margin tax provision recognized Margin Tax Provision Recognized Margin Tax Provision Recognized Consolidated Statements of Cash Flows (Unaudited) [Abstract] Consolidated Statements of Cash Flows (Unaudited) [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] 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 Depreciation, Depletion and Amortization Amortization of deferred loan costs Amortization of Financing Costs and Discounts Amortization of notes payable discount Amortization of Debt Discount (Premium) Gain on sale of marketable securities Marketable Securities, Realized Gain (Loss), Excluding Other than Temporary Impairments Loss (gain) on sale or disposal of assets and properties Loss (Gain) on Sale or Disposal of Assets and Properties Loss (Gain) on Sale or Disposal of Assets and Properties Bad debt expense Provision for Doubtful Accounts Share-based compensation Share-based Compensation Changes in operating assets and liabilities: Increase (Decrease) in Other Operating Assets and Liabilities, Net [Abstract] Escrows and acquisition deposits Increase (Decrease) in Deposits Outstanding Accrued rent and accounts receivable Increase (Decrease) in Accounts and Other Receivables Unamortized lease commissions Increase (Decrease) in Unamortized Lease Commissions and Loan Costs The increase (decrease) during the reporting period in the unamortized balance of monies given as lease commissions and loan costs. Lease commission costs are costs incurred by the lessor to originate a lease with independent third parties and the lessor's leasing agents that would not have been incurred had that leasing transaction not occurred. Unamortized lease commissions are charged against earnings over the life of the lease. Loan costs are capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain. Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Accounts payable and accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Tenants' security deposits Increase (Decrease) in Security Deposits Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Acquisitions of real estate Payments to Acquire Real Estate Additions to real estate Payments to Develop Real Estate Assets Investments in marketable securities Payments to Acquire Available-for-sale Securities Proceeds from sale of property Proceeds from Sale of Property, Plant, and Equipment Proceeds from sales of marketable securities Proceeds from Sale of Available-for-sale Securities Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Distributions paid to OP unitholders Payments of Ordinary Dividends, Noncontrolling Interest Proceeds from issuance of common shares Proceeds from Issuance of Common Stock Payments of exchange offer costs Payments of Stock Issuance Costs Proceeds from notes payable Proceeds from Notes Payable Proceeds from revolving credit facility, net Proceeds from Long-term Lines of Credit Repayments of notes payable Repayments of Notes Payable Payments of loan origination costs Payments of Loan Costs Net cash provided by financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents at beginning of period Cash and cash equivalents at end of period Individual Trustee Grant Agreements [Member] Individual Trustee Grant Agreements [Member] Individual Trustee Grant Agreements [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Award Type [Domain] Stock Options [Member] Stock Options [Member] Number of independent trustees (in trustees) Number of Independent Trustees Number of Independent Trustees Restricted stock granted to each trustee (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Restricted stock granted to trustees, vested in period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Restricted stock granted to trustees, weighted-average grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Performance Shares [Member] Performance Shares [Member] Non-Vested Time Based Shares [Member] Non-Vested Time Based Shares [Member] Non-Vested Time Based Shares [Member] Percentage of maximum number of shares issued under plan to aggregate shares Percentage of Maximum Number of Shares Issued Under Plan to Aggregate Shares Percentage of Maximum Number of Shares Issued Under Plan to Aggregate Shares Unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Award vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Unrecognized compensation cost, period for recognition (in years) Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Portion Attributable to Over-Allotment Option [Member] Portion Attributable to Over-Allotment Option [Member] Portion Attributable to Over-Allotment Option [Member] Distributions Made to Member or Limited Partner by Distribution Type [Axis] Distributions Made to Member or Limited Partner by Distribution Type [Axis] Distribution Type [Domain] Distribution Type [Domain] Cash Distribution [Member] Cash Distribution [Member] Stock Conversion Description [Axis] Stock Conversion Description [Axis] Conversion of Stock, Name [Domain] Conversion of Stock, Name [Domain] First Exchange Offer [Member] First Exchange Offer [Member] First Exchange Offer [Member] Second Exchange Offer [Member] Second Exchange Offer [Member] Second Exchange Offer [Member] Third Exchange Offer [Member] Third Exchange Offer [Member] Third Exchange Offer [Member] Preferred Stock [Member] Preferred Stock [Member] Class of Stock [Line Items] Class of Stock [Line Items] Common shares, authorized (in shares) Common Stock, Shares Authorized Common shares, par value per share (in dollars per share) Common Stock, Par or Stated Value Per Share Preferred shares, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred shares, par value per share (in dollars per share) Preferred Stock, Par or Stated Value Per Share Common shares, issued (in shares) Common Stock, Shares, Issued Share price of equity offering Share Price Ownership interest in operating partnership Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest Conversion ratio for class A common stock to OP unit Conversion Ratio for Class A Common Stock to OP Unit Conversion Ratio for Class A Common Stock to OP Unit OP units outstanding (in shares) Units of Partnership Interest, Amount OP units owned (in shares) Weighted-average share ownership in operating partnership Weighted-Average Share Ownership in Operating Partnership Weighted-Average Share Ownership in Operating Partnership Cash distribution paid (in dollars per share) Distribution Made to Member or Limited Partner, Distributions Paid, Per Unit Cash distribution paid Distribution Made to Member or Limited Partner, Cash Distributions Paid Common stock exchange offer, conversion basis for one share or unit (in shares) Common Stock Exchange Offer, Conversion Basis for One Share or Unit Common Stock Exchange Offer, Conversion Basis for One Share or Unit. Common shares, outstanding (in shares) Common Stock, Shares, Outstanding Conversion of stock, shares converted (in shares) Conversion of Stock, Shares Converted Schedule of Unamortized Leasing Comissions and Loan Costs Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Shares, Non-vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Weighted-Average Grant Date Fair Value, Non-vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Non-Vested Outstanding, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Non-Vested Outstanding, Weighted Average Grant Date Fair Value Shares, Granted (in shares) Weighted-Average Grant Date Fair Value, Granted (in dollars per share) Weighted-Average Grant Date Fair Value, Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Weighted Average Grant Date Fair Value Shares, Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period Weighted-Average Grant Date Fair Value, Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeited in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeited in Period, Weighted Average Grant Date Fair Value Shares, Non-vested (in shares) Weighted-Average Grant Date Fair Value, Non-vested (in dollars per share) Shares, Available for grant (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant Document and Entity Information [Abstract] Document and Entity Information [Abstract] Entities [Table] Entities [Table] Entity Information [Line Items] Entity Information [Line Items] 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 Consolidated Statements of Income [Abstract] Consolidated Statements of Income [Abstract] Property revenues Real Estate Revenue, Net [Abstract] Rental revenues Operating Leases, Income Statement, Minimum Lease Revenue Other revenues Tenant Reimbursement and Other Revenue Tenant Reimbursement and Other Revenue Includes tenant reimbursements in accordance with the provisions of their lease agreement, this element represents allowable charges due a landlord from its tenant. In retail store and office building leases, for example, tenant reimbursements may cover items such as taxes, utilities, and common area expenses. Also includes other real estate revenue not otherwise specified in the taxonomy. Total property revenues Real Estate Revenue, Net Property expenses Operating Expenses [Abstract] Property operation and maintenance Cost of Property Repairs and Maintenance Real estate taxes Real Estate Tax Expense Total property expenses Operating Costs and Expenses Other expenses (income) Operating Costs and Expenses [Abstract] General and administrative General and Administrative Expense Depreciation and amortization Other Depreciation and Amortization Interest expense Interest Expense Interest, dividend and other investment income Investment Income, Interest and Dividend Total other expense Total other expense Total other expense Total general and administrative expense, depreciation and amortization expense, interest expense and interest, dividend and other investment income, net. Income before loss on sale or disposal of assets and income taxes Income from continuing operations before loss on disposal of assets and income taxes The sum of total property revenues, total property expenses and total other expense. Provision for income taxes Income Tax Expense (Benefit) Gain (loss) on sale or disposal of assets Gain (Loss) on Disposition of Assets Income before gain on sale of property Income Before Gain on Sale of Property Income Before Gain on Sale of Property Gain on sale of property Gain (Loss) on Sale of Property Plant Equipment Net income Basic and Diluted Earnings Per Unit: Net income attributable to unitholders excluding amounts attributable to unvested restricted shares Earnings Per Share, Basic and Diluted Weighted average number of units outstanding: Weighted average number of common shares outstanding: [Abstract] Weighted average number of common shares outstanding. Basic (in shares) Diluted (in shares) Distributions declared per OP unit (in dollars per share) Common Stock, Dividends, Per Share, Declared Consolidated Statements of Comprehensive Income (Loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Other comprehensive gain (loss) Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized loss on cash flow hedging activities Unrealized Gain (Loss) on Cash Flow Hedging Instruments Unrealized gain (loss) on available-for-sale marketable securities Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Receivables [Abstract] Tenant receivables Tenant Receivables Tenant Receivables Accrued rents and other recoveries Accrued Rent and Other Recoveries Accrued Rent and Other Recoveries Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable Total Income Taxes Income Tax Disclosure [Text Block] 2012 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2013 Long-term Debt, Maturities, Repayments of Principal in Year Two 2014 Long-term Debt, Maturities, Repayments of Principal in Year Three 2015 Long-term Debt, Maturities, Repayments of Principal in Year Four 2016 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Total Statement of Partners' Capital [Abstract] Partner Capital Components [Axis] Partner Capital Components [Domain] Partner Capital Components [Domain] Accumulated Other Comprehensive Income (Loss) [Member] Partner Type [Axis] Partner Type of Partners' Capital Account, Name [Domain] Partner Type of Partners' Capital Account, Name [Domain] General Partner [Member] Limited Partner [Member] Increase (Decrease) in Partners' Capital [Roll Forward] Beginning balance Beginning balance - general partner units (in shares) Beginning balance - limited partner units (in shares) Exchange of noncontrolling interest OP units and Class A common shares for Class B common shares (shares) Stock Issued During Period, Shares, Conversion of Units Exchange of noncontrolling interest OP units and Class A common shares for Class B common shares (value) Exchange offer costs Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Issuance of OP units, net of costs (shares) Stock Issued During Period, Shares, New Issues Issuance of OP units, net of costs (value) Stock Issued During Period, Value, New Issues Issuance of shares under distribution reinvestment plan (shares) Stock Issued During Period, Shares, Dividend Reinvestment Plan Issuance of shares under distribution reinvestment plan (value) Stock Issued During Period, Value, Dividend Reinvestment Plan Share-based compensation (shares) Stock Issued During Period, Shares, Restricted Stock Award, Forfeited Share-based compensation (value) Adjustments to Additional Paid in Capital, Share-based Compensation, Nonvested Shares, Requisite Service Period Recognition Distributions Dividends Unrealized loss on change in value of cash flow hedge Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Unrealized gain on change in fair value of available-for-sale marketable securities Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax Ending balance - general partner units (in shares) Ending balance - limited partner units (in shares) Ending balance Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Debt Disclosure Debt Disclosure [Text Block] Equity Stockholders' Equity Note Disclosure [Text Block] Accounting Policies [Abstract] Significant Accounting Policies Significant Accounting Policies [Text Block] Related Party Transactions Related Party Transactions Disclosure [Text Block] Real Estate [Table] Real Estate [Table] Real Estate [Table] Real Estate Property Ownership [Axis] Real Estate Property Ownership [Axis] Real Estate Properties [Domain] Real Estate Properties [Domain] Not Owned Property [Member] Not Owned Property [Member] Not Owned Property [Member] Property Acquisitions and Dispositions, Name [Axis] Property Acquisitions and Dispositions, Name [Axis] Property Acquisitions and Dispositions, Name [Axis] Property Acquisitions and Dispositions, Name [Domain] Property Acquisitions and Dispositions, Name [Domain] Property Acquisitions and Dispositions, Name [Domain] Village Square at Dana Park [Member] Village Square at Dana Park [Member] Village Square at Dana Park [Member] Village Square at Dana Park Adjacent Parcel [Member] Village Square at Dana Park Adjacent Parcel [Member] Village Square at Dana Park Adjacent Parcel [Member] Fountain Square [Member] Fountain Square [Member] Fountain Square [Member] Shops at Pinnacle Peak [Member] Shops at Pinnacle Peak [Member] Shops at Pinnacle Peak [Member] Shops at Starwood [Member] Shops at Starwood [Member] Shops at Starwood [Member] Starwood Phase III [Member] Starwood Phase III [Member] Starwood Phase III [Member] Pinnacle of Scottsdale Phase II [Member] Pinnacle of Scottsdale Phase II [Member] Pinnacle of Scottsdale Phase II [Member] Phase I of Pinnacle of Scottsdale [Member] Phase I of Pinnacle of Scottsdale [Member] Phase I of Pinnacle of Scottsdale [Member] Ahwatukee Plaza Shopping Center [Member] Ahwatukee Plaza Shopping Center [Member] Ahwatukee Plaza Shopping Center [Member] Terravita Marketplace [Member] Terravita Marketplace [Member] Terravita Marketplace [Member] Gilbert Tuscany Village [Member] Gilbert Tuscany Village [Member] Gilbert Tuscany Village [Member] Desert Canyon Shopping Center [Member] Desert Canyon Shopping Center [Member] Desert Canyon Shopping Center [Member] Greens Road Plaza [Member] Greens Road Plaza [Member] Greens Road Plaza [Member] Real Estate [Line Items] Real Estate [Line Items] Real Estate [Line Items] Payments to acquire property Property percentage occupied Property Percentage Occupied Property Percentage Occupied Gross leasable area (in square feet) Net Rentable Area Area of land (in acres) Area of Land Property acquisitions, purchase price Property Acquisitions, Purchase Price Property Acquisitions, Purchase Price Non-recourse loan Non-Recourse Debt Lenght of frontage road (in feet) Lenght of Frontage Road Lenght of Frontage Road Net rentable area pursuant to ground leases (in square feet) Net Rentable Area Pursuant to Ground Leases Net Rentable Area Pursuant to Ground Leases Number of tenants (in tenants) Number of Tenants Number of Tenants Home prices of gated golf course residential community that is adjacent to property acquisition Home Prices of Gated Golf Course Residential Community that Is Adjacent to Property Acquisition Home Prices of Gated Golf Course Residential Community that Is Adjacent to Property Acquisition Square footage of property (in square feet) Area of Real Estate Property Gain on property dispositions Schedule of Share-Based Incentive Plan Activity Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Nonvested and Vested Shares Activity Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding [Table Text Block] Marketable Securities Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Accrued Rent and Accounts Receivable, Net Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Summary of Significant Accounting Policies [Table] Summary of Significant Accounting Policies [Table] Summary of Significant Accounting Policies [Table] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging [Member] Cash Flow Hedging [Member] Derivative Instrument Risk [Axis] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] Derivative Contract Type [Domain] Interest Rate Swap [Member] Interest Rate Swap [Member] Summary of Significant Accounting Policies [Line Items] Summary of Significant Accounting Policies [Line Items] [Line Items] for Summary of Significant Accounting Policies [Table] Conversion basis for common shares to OP units Conversion Basis for Common Shares to OP Units Conversion Basis for Common Shares to OP Units Gains on the sale of marketable securities Investment in available-for-sale marketable securities Aggregate unrealized loss on available-for-sale marketable securities Available-for-sale Securities, Gross Unrealized Gain (Loss) Variable rate note assumed Business Acquisition, Purchase Price Allocation, Notes Payable and Long-term Debt Fair value of cash flow hedge Cash Flow Hedge Derivative Instrument Assets at Fair Value Cash flow hedge recognized into earnings Derivative Instruments, Gain (Loss) Recognized in Income, Net Cash flow hedge losses recognized as other comprehensive loss Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Interest expense capitalized Interest Costs Capitalized Real estate tax capitalized Real Estate Taxes, Capitalized Real Estate Taxes, Capitalized Earnings Per Share Earnings Per Share [Text Block] Basis of Consolidation Consolidation, Policy [Policy Text Block] Basis of Accounting Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Reclassifications Reclassification, Policy [Policy Text Block] Marketable Securities Marketable Securities, Policy [Policy Text Block] Derivative Instruments and Hedging Activities Derivatives, Policy [Policy Text Block] Development Properties Real Estate Held for Development and Sale, Policy [Policy Text Block] Share-Based Compensation Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Schedule of Accrued Rent and Accounts Receivable, Net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Schedule of Real Estate Properties [Table] Schedule of Real Estate Properties [Table] Wholly Owned Properties [Member] Wholly Owned Properties [Member] Real Estate Properties [Line Items] Real Estate Properties [Line Items] Number of commercial properties Number of Real Estate Properties Subsequent Event [Table] Subsequent Event [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Major Types of Debt and Equity Securities [Domain] Exchange Traded Funds [Member] Exchange Traded Funds [Member] Real Estate Sector Mutual Funds [Member] Real Estate Sector Mutual Funds [Member] Real Estate Sector Mutual Funds [Member] Real Estate Common Stock [Member] Real Estate Common Stock [Member] Real Estate Common Stock [Member] Schedule of Available-for-sale Securities [Line Items] Schedule of Available-for-sale Securities [Line Items] Amortized Cost Available-for-sale Securities, Amortized Cost Basis Gains in Accumulated Other Comprehensive Income Available-for-sale Securities, Gross Unrealized Gains Losses in Accumulated Other Comprehensive Income Available-for-sale Securities, Gross Unrealized Losses Estimated Fair Value Available-for-sale Securities, Fair Value Disclosure Gross realized gains on sale of marketable securities Available-for-sale Securities, Gross Realized Gains Gross realized losses on sale of marketable securities Available-for-sale Securities, Gross Realized Losses