Supplemental Cash Flow Elements [Abstract] 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] ASU 2017-05 Accounting Standards Update 2017-05 [Member] Accounting Standards Update 2017-05 [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Deposits applied to sales of real estate Escrow Deposits Related to Property Sales Amortization of net discounts on debt Amortization of Debt Discount (Premium) Accrued capital expenditures and deferred lease costs Other Significant Noncash Transactions, Capital Expenditures Incurred but Not yet Paid and Deferred Leasing Costs, Noncash Other Significant Noncash Transactions, Capital Expenditures Incurred but Not yet Paid and Deferred Leasing Costs, Noncash Market value adjustments to interest rate swaps that qualify for hedge accounting treatment Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Cumulative-effect adjustment for the adoption of ASU 2017-05 Cumulative Effect of New Accounting Principle in Period of Adoption Common stock issued to employees and directors, and amortized (net of income tax withholdings) Common Stock Issued, Value, Net of Shares for Tax Withholdings Common Stock Issued, Value, Net of Shares for Tax Withholdings Condensed Financial Information of Parent Company Only Disclosure [Abstract] Schedule of Condensed Financial Statements Condensed Financial Statements [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Reportable Legal Entities Reportable Legal Entities [Member] Eliminations Consolidation, Eliminations [Member] Consolidated Entities [Axis] Consolidated Entities [Axis] Consolidated Entities [Domain] Consolidated Entities [Domain] Columbia Property Trust (Parent) (Guarantor) Parent Company [Member] Columbia Property Trust OP (the Issuer) Subsidiary Issuer [Member] Non- Guarantors Non-Guarantor Subsidiaries [Member] Condensed Financial Statements, Captions [Line Items] Condensed Financial Statements, Captions [Line Items] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Net proceeds from sale of investments in unconsolidated joint ventures Proceeds from Divestiture of Interest in Joint Venture Net proceeds from the sales of real estate Proceeds from Sale of Real Estate Held-for-investment Investment in real estate and related assets Payments to Acquire and Develop Real Estate and Lease Acquisition Costs Payments to Acquire and Develop Real Estate and Lease Acquisition Costs Investments in unconsolidated joint ventures Payments to Acquire Interest in Joint Venture Distributions from unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution, Return of Capital Distributions from subsidiaries Payments for (Proceeds from) Businesses and Interest in Affiliates Net cash provided by investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Borrowings, net of fees Proceeds from Notes Payable, Net of Financing Costs Proceeds from Notes Payable, Net of Financing Costs Repayments Repayments of Long-term Debt Distributions Distributions Paid to Stockholders for Dividends and Reinvested Shares of Common Stock Distributions Paid to Stockholders for Dividends and Reinvested Shares of Common Stock Repurchases of common stock Payments for Repurchase of Common Stock Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Cash and cash equivalents, beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents, end of period Increase (decrease) in net proceeds from sales of real estate Increase (Decrease) of Proceeds from Sale of Real Estate Held-for-investment Increase (Decrease) of Proceeds from Sale of Real Estate Held-for-investment Increase (decrease) in distributions from subsidiaries Increase (Decrease) in Proceeds from Businesses and Interest in Affiliates Increase (Decrease) in Proceeds from Businesses and Interest in Affiliates Increase (decrease) in distributions Increase (Decrease) of Distributions Paid to Stockholders for Dividends and Reinvested Shares of Common Stock Increase (Decrease) of Distributions Paid to Stockholders for Dividends and Reinvested Shares of Common Stock Equity [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Title of Individual [Axis] Title of Individual [Axis] Relationship to Entity [Domain] Relationship to Entity [Domain] Director Director [Member] Award Date [Axis] Award Date [Axis] Award Date [Domain] Award Date [Domain] January 3, 2017 January 03, 2017 [Member] January 03, 2017 [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Grant-Date Fair Value (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 Segment Reporting [Abstract] Reconciliation of Revenue from Segments to Consolidated Reconciliation of Revenue from Segments to Consolidated [Table Text Block] Schedule of Segment Reporting Information, by Segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Real Estate [Abstract] Real Estate Transactions Real Estate Disclosure [Text Block] Accounting Policies [Abstract] Schedule of Finite-Lived Intangible Assets by Major Class Schedule of Finite-Lived Intangible Assets [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] Intangible below market ground lease assets Below-Market Lease Assets [Member] Below-Market Lease Assets [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] For the remainder of 2018 Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year For the Years Ending December 31: Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] 2019 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2020 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Five 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Six Finite-Lived Intangible Assets, Amortization Expense, Year Six Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Six Finite-Lived Intangible Assets, Amortization Expense, after Year Six Intangible lease assets, net Finite-Lived Intangible Assets, Net Equity Method Investments and Joint Ventures [Abstract] Unconsolidated Joint Ventures Equity Method Investments and Joint Ventures Disclosure [Text Block] Segment Information Segment Reporting Disclosure [Text Block] Income Statement [Abstract] Revenues: Revenues [Abstract] Rental income Operating Leases, Income Statement, Lease Revenue Tenant reimbursements Tenant Reimbursements Hotel income Revenue from Owned Hotels Asset and property management fee income Property Management Fee Revenue Other property income Other Real Estate Revenue Revenues Revenues Expenses: Operating Expenses [Abstract] Property operating costs Direct Costs of Leased and Rented Property or Equipment Hotel operating costs Direct Costs of Hotels Asset and property management fee expenses Owned Property Management Costs Depreciation Depreciation Amortization Amortization General and administrative – corporate General and Administrative Expense, Corporate General and Administrative Expense, Corporate General and administrative – unconsolidated joint ventures General and Administrative Expense, Unconsolidated Joint Venture General and Administrative Expense, Unconsolidated Joint Venture Costs and expenses Operating Expenses Real estate operating income Operating Income (Loss) Other Income (Expense): Nonoperating Income (Expense) [Abstract] Interest expense Interest Expense Interest and other income Interest and Other Income Gain on sale of unconsolidated joint venture interests Equity Method Investment, Realized Gain (Loss) on Disposal Loss on early extinguishment of debt Gain (Loss) on Extinguishment of Debt Nonoperating income (expense) Nonoperating Income (Expense) Income (loss) before income taxes, unconsolidated joint ventures, and sales of real estate Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Income tax benefit (expense) Income Tax Expense (Benefit) Income (loss) from unconsolidated joint ventures Income (Loss) from Equity Method Investments, Joint Ventures Income (Loss) from Equity Method Investments, Joint Ventures Income before sales of real estate Income (Loss) from Continuing Operations Before Gain or Loss on Sale of Properties This element is for Real Estate Investment Trust (REIT) statement of income purposes. It represents the income or loss from continuing operations Gains on sales of real estate assets Gain (Loss) on Sale of Properties, Net of Applicable Income Taxes Net income Net Income (Loss) Attributable to Parent Per-Share Information – Basic: Earnings Per Share, Basic [Abstract] Net income (dollars per share) Earnings Per Share, Basic Weighted-average common shares outstanding – basic Weighted Average Number of Shares Outstanding, Basic Per-Share Information – Diluted: Earnings Per Share, Diluted [Abstract] Net income (dollars per share) Earnings Per Share, Diluted Weighted-average common shares outstanding – diluted Weighted Average Number of Shares Outstanding, Diluted Dividends per share (dollars per share) Common Stock, Dividends, Per Share, Cash Paid Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Corporate Joint Venture Corporate Joint Venture [Member] Legal Entity [Axis] Legal Entity [Axis] Entity [Domain] Entity [Domain] Blackstone Property Partners Blackstone Property Partners [Member] Blackstone Property Partners [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Number of joint ventures that qualify as variable interest entities Number Of Joint Ventures That Qualify As Variable Interest Entities Number Of Joint Ventures That Qualify As Variable Interest Entities Mortgage note transferred to joint venture Real Estate Investments, Joint Ventures, Debt Real Estate Investments, Joint Ventures, Debt Mortgage note interest rate Debt Instrument, Interest Rate, Stated Percentage Guaranty liability Guaranty Liabilities Shares Rollforward Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Unvested shares - beginning of period (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Granted (shares) Vested (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Forfeited (shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Unvested shares - end of period (shares) Weighted-Average, Grant-Date Fair Value Rollforward Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Unvested shares - beginning of period (dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Granted (dollars per share) Vested (dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Forfeited (dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Unvested shares - end of period (dollars per share) Shares expected to ultimately vest Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Expected to Vest Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Expected to Vest Expected forfeiture rate Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Expected Forfeiture Rate Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Expected Forfeiture Rate Schedule of Estimated Useful Lives for Real Estate Assets Schedule of Estimated Useful Lives for Real Estate Assets [Table Text Block] Schedule of Estimated Useful Lives for Real Estate Assets [Table Text Block] Schedule of Intangible Assets and Liabilities Schedule of Intangible Assets and Liabilities [Table Text Block] Schedule of Intangible Assets and Liabilities [Table Text Block] Schedule of Future Amortization Expense for Remaining Net Below-Market Lease Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Schedule of Interest Rate Swaps Schedule of Interest Rate Derivatives [Table Text Block] Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block] Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract Type [Domain] Derivative Contract [Domain] Interest rate contracts Interest Rate Contract [Member] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Prepaid expenses and other assets Prepaid Expenses and Other Assets [Member] Prepaid Expenses and Other Assets [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Derivative, Fair Value, Net [Abstract] Derivative, Fair Value, Net [Abstract] Derivative designated as hedging instruments Derivative Instruments in Hedges, at Fair Value, Net Summary of Derivative Instruments Impact on Results of Operations [Abstract] Summary of Derivative Instruments Impact on Results of Operations [Abstract] Market value adjustment to interest rate swaps designated as hedging instruments and included in other comprehensive income Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Revenue from Contract with Customer [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Difference between Revenue Guidance in Effect before and after Topic 606 Difference between Revenue Guidance in Effect before and after Topic 606 [Member] ASU 2014-09 Accounting Standards Update 2014-09 [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Lease termination revenue Lease Termination Revenue Lease Termination Revenue Lease override fees receivable Lease Override Fees Receivable Lease Override Fees Receivable Retained earnings Retained Earnings (Accumulated Deficit) Salary and other reimbursement revenue Salary And Other Reimbursement Revenue Salary And Other Reimbursement Revenue Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Twitter Twitter [Member] Twitter [Member] Room & Board Room & Board [Member] Room & Board [Member] Red Bull North America Red Bull North America [Member] Red Bull North America [Member] Company 3 Company 3 [Member] Company 3 [Member] SY Partners SY Partners [Member] SY Partners [Member] SAE SAE [Member] SAE [Member] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Customer Concentration Risk Customer Concentration Risk [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Allianz Allianz [Member] Allianz [Member] L & L Holding Company L & L Holding Company [Member] L & L Holding Company [Member] Investment, Name [Axis] Investment, Name [Axis] Investment, Name [Domain] Investment, Name [Domain] 1800 M Street Joint Venture Eighteen Hundred M Street [Member] Eighteen Hundred M Street [Member] 114 Fifth Avenue Joint Venture One Fourteen Fifth Avenue Joint Venture [Member] One Fourteen Fifth Avenue Joint Venture [Member] Real Estate, Type of Property [Axis] Real Estate, Type of Property [Axis] Real Estate [Domain] Real Estate [Domain] Office Building Office Building [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] 149 Madison Avenue One Forty Nine Madison Avenue [Member] One Forty Nine Madison Avenue [Member] 245 - 249 West 17th Street Two Forty Five - Two Forty Nine West 17th Street [Member] Two Forty Five - Two Forty Nine West 17th Street [Member] 218 West 18th Street Two Eighteen West 18th Street [Member] Two Eighteen West 18th Street [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Square feet of real estate Area of Real Estate Property Ownership percentage Equity Method Investment, Ownership Percentage Percentage of buildings leased Lessor, Operating Lease, Percent Leased Lessor, Operating Lease, Percent Leased Investments in unconsolidated joint ventures Business Combination, Consideration Transferred Number of tenants Number of Tenants Number of Tenants Concentration risk, percentage Concentration Risk, Percentage Schedule of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Market Square Joint Venture Market Square Joint Venture [Member] Market Square Joint Venture [Member] University Circle Joint Venture University Circle Joint Venture [Member] University Circle Joint Venture [Member] 333 Market Street Joint Venture Three Thirty-Three Market Street Joint Venture [Member] Three Thirty-Three Market Street Joint Venture [Member] Market Square, University Circle, 333 Market Street, 114 Fifth Avenue And 1800 M Street Joint Ventures Market Square, University Circle, 333 Market Street, 114 Fifth Avenue And 1800 M Street Joint Ventures [Member] Market Square, University Circle, 333 Market Street, 114 Fifth Avenue And 1800 M Street Joint Ventures [Member] Schedule of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Total assets Equity Method Investment, Summarized Financial Information, Assets Total debt Equity Method Investment, Summarized Financial Information, Liabilities Total equity Equity Method Investment Summarized Financial Information, Equity Aggregate basis difference Equity Method Investment, Difference Between Carrying Amount and Underlying Equity Debt Disclosure [Abstract] Schedule of Line of Credit and Notes Payable Indebtedness Schedule of Debt [Table Text Block] Significant Noncash Investing and Financing Activities Schedule of Other Significant Noncash Transactions [Table Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock Common Stock [Member] Statement [Line Items] Statement [Line Items] Distributions to common stockholders per share (dollars per share) Intangible lease assets Leases, Acquired-in-Place [Member] Intangible lease origination costs Intangible Lease Origination Costs [Member] Intangible Lease Origination Costs [Member] Land Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land Building and improvements Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings and Improvements Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings and Improvements Intangible lease Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Intangible below market lease liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Below-Market Lease Liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Below-Market Lease Liability Total purchase price Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Above-Market In-Place Lease Assets Above-Market In-Place Lease Assets [Member] Above-Market In-Place Lease Assets [Member] Absorption Period Costs Absorption Period Costs [Member] Absorption Period Costs [Member] Intangible Lease Origination Costs Gross Intangible In-Place Lease Assets and Liabilities [Abstract] Gross Intangible In-Place Lease Assets and Liabilities [Abstract] Gross Intangible In-Place Lease Assets and Liabilities [Abstract] Intangible Lease Assets, Gross Finite-Lived Intangible Assets, Gross Intangible Lease Assets, Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Intangible Lease Origination Costs, Gross Finite-Lived Intangible Asset, Acquired-in-Place Leases, Gross Finite-Lived Intangible Asset, Acquired-in-Place Leases, Gross Intangible Lease Origination Costs, Accumulated Amortization Finite Lived Intangible Assets, Acquired in Place leases, Accumulated Amortization The accumulated amount of amortization of finite-lived intangible assets for acquired in-place leases. Intangible Lease Origination Costs, Net Finite-Lived Intangible Asset, Acquired-in-Place Leases Below Market Lease, Gross Below Market Lease, Gross Below Market Lease, Accumulated Amortization Below Market Lease, Accumulated Amortization Below Market Lease, Net Below Market Lease, Net Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] 333 Market Street and University Circle Three Thirty-Three Market Street Joint Venture and University Circle Joint Venture [Member] Three Thirty-Three Market Street Joint Venture and University Circle Joint Venture [Member] Operating Segments Operating Segments [Member] Hotel Segment Reconciling Items [Member] Corporate Corporate, Non-Segment [Member] Eliminations Intersegment Eliminations [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] New York New York Segment [Member] New York Segment San Francisco San Francisco Segment [Member] San Francisco Segment Atlanta Atlanta Segment [Member] Atlanta Segment Washington, D.C. Washington, D.C. Segment [Member] Washington, D.C. Segment Boston Boston Segment [Member] Boston Segment Los Angeles Los Angeles Segment [Member] Los Angeles Segment All other office markets All Other Markets Segment [Member] All Other Markets Segment Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Operating revenues including unconsolidated joint venture Revenues, Including Unconsolidated Joint Venture Revenues, Including Unconsolidated Joint Venture Operating revenues Asset and property management fee income Segment Reconciling Items Net income Amortization Adjustment For Amortization Continuing Operations The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives for continuing operations Net interest expense Interest Income (Expense), Net Interest income from development authority bonds Interest Income, Development Authority Bonds Interest Income, Development Authority Bonds Gain on sale of unconsolidated joint venture interests Loss on early extinguishment of debt Gain (Loss) On Extinguishment of Debt Continuing Operations Gain (Loss) On Extinguishment of Debt Continuing Operations Income tax expense (benefit) Adjustments included in income (loss) from unconsolidated joint ventures Income (Loss) from Equity Method Investments, Adjustment Income (Loss) from Equity Method Investments, Adjustment Gain on sales of real estate assets NOI Net Operating Income (Loss) Net Operating Income (Loss) Statement of Comprehensive Income [Abstract] Market value adjustment to interest rate swap Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Revenues Business Acquisition, Pro Forma Revenue Net income Business Acquisition, Pro Forma Net Income (Loss) Net income per share – basic (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Basic Net income per share – diluted (in dollars per share) Business Acquisition, Pro Forma Earnings Per Share, Diluted Statement of Cash Flows [Abstract] Cash Flows From Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest 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] Straight-line rental income Straight Line Rent Amortization Amortization of Intangible Assets Noncash interest expense Noncash interest expense The component of interest expense representing interest paid other than in cash for example by increasing the balance of debt securities and the noncash expenses charged against earnings in the period to amortize debt discount and premium associated with the related debt instruments. Loss on early extinguishment of debt Income (loss) from unconsolidated joint ventures Distributions of earnings from unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution Gain on sales of real estate assets Gain (Loss) on Sale of Properties Stock-based compensation expense Share-based Compensation Changes in assets and liabilities, net of acquisitions and dispositions: Changes in assets and liabilities, net of acquisitions [Abstract] Changes in assets and liabilities, net of acquisitions [Abstract] Decrease (increase) in tenant receivables, net Increase (Decrease) in Accounts Receivable 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 deferred income Increase (Decrease) in Deferred Revenue Net cash provided by operating activities Cash Flows From Investing Activities: Prepaid earnest money Payments for Deposits on Real Estate Acquisitions Capital improvement and development costs Payments to Acquire and Develop Real Estate Deferred lease costs paid Increase (Decrease) in Lease Acquisition Costs Cash Flows From Financing Activities: Financing costs paid Payments of Financing Costs Proceeds from lines of credit and notes payable Proceeds from Notes Payable Repayments of lines of credit and notes payable Repayments of Notes Payable Distributions paid to stockholders Payments of Dividends Redemptions of common stock Total Revenues Equity Method Investment, Summarized Financial Information, Revenue Net Income (Loss) Equity Method Investment, Summarized Financial Information, Net Income (Loss) Columbia Property Trust's Share of Net Income (Loss) Earnings Per Share [Abstract] Earnings Per Share Earnings Per Share [Text Block] Revenues Revenue from Contract with Customer [Text Block] Disposal Groups, Including Discontinued Operations [Table] Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Group Name [Domain] Disposal Group Name [Domain] University Circle & 333 Market Street Key Center Tower & Marriott Key Center Tower and Key Center Marriot [Member] Key Center Tower and Key Center Marriot [Member] Houston Properties Houston Properties [Member] Houston Properties [Member] Disposal Group Classification [Axis] Disposal Group Classification [Axis] Disposal Group Classification [Domain] Disposal Group Classification [Domain] Disposed of by Sale Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] % Sold Equity Method Investment, Ownership Percentage Sold During Period Equity Method Investment, Ownership Percentage Sold During Period Sales Price Disposal Group, Including Discontinued Operation, Consideration Gain (Loss) on Sale Gains (Losses) on Sales of Investment Real Estate 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] Employees Employees [Member] Employees [Member] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Future employee awards Deferred Compensation Arrangement with Individual, Compensation Expense 245 - 249 West 17th Street & 218 West 18th Street Two Forty Five - Two Forty Nine West 17th Street & Two Eighteen West 18th Street [Member] Two Forty Five - Two Forty Nine West 17th Street & Two Eighteen West 18th Street [Member] Ownership Interest Purchase Price Payments to Acquire Real Estate Purchase Price Consolidating Adjustments Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Schedule of Long-term Debt Instruments Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Loans Payable Loans Payable [Member] Term Loans Notes Payable to Banks [Member] Bridge Loan Bridge Loan [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] $300 Million Term Loan $300 Million Term Loan, Maturity July 2020 [Member] $300 Million Term Loan, Maturity July 2020 [Member] $300 Million Bridge Loan Three Hundred Million Dollar Bridge Loan, Maturity November 2018 [Member] Three Hundred Million Dollar Bridge Loan, Maturity November 2018 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Estimated fair value of line of credit and notes payable Debt Instrument, Fair Value Disclosure Carrying value of the line of credit and notes payable Loans Payable Excluding Deferred Financing Costs Loans Payable Excluding Deferred Financing Costs Face amount of issued debt instrument Debt Instrument, Face Amount Interest payments Interest Paid Interest capitalized Interest Costs Capitalized Repayment of debt Repayments of Debt Assets: Assets [Abstract] Land Land Buildings and improvements, net Investment Building And Building Improvements , Net Aggregate of the carrying amounts as of the balance sheet date of investments in building and building improvements net of accumulated depreciation Intangible lease assets, net Construction in progress Construction in Progress, Gross Total real estate assets Real Estate Investment Property, Net Investments in unconsolidated joint ventures Real Estate Investments, Joint Ventures Cash and cash equivalents Investment in subsidiaries Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Tenant receivables, net of allowance Accounts and Notes Receivable, Net Straight-line rent receivable Deferred Rent Receivables, Net Prepaid expenses and other assets Prepaid Expense and Other Assets Intangible lease origination costs, net Deferred lease costs, net Deferred Costs, Leasing, Net Investment in development authority bonds Investment in Development Authority Bonds Investments in development authority bonds which were assumed upon acquisition of certain real estate assets and allow for property tax abatement benefits over the term of the agreement. Total assets Assets Liabilities: Liabilities [Abstract] Lines of credit and notes payable, net Loans Payable Bonds payable, net Unsecured Debt Accounts payable, accrued expenses, and accrued capital expenditures Accounts Payable and Accrued Liabilities Dividends payable Dividends Payable Due to affiliates Due to Related Parties Deferred income Deferred Revenue Intangible lease liabilities, net Off-market Lease, Unfavorable Obligations under capital lease Capital Lease Obligations, Noncurrent Total liabilities Liabilities Equity: Stockholders' Equity, Number of Shares, Par Value and Other Disclosures [Abstract] Total equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and equity Liabilities and Equity Schedule of Properties Acquired Schedule of Business Acquisitions, by Acquisition [Table Text Block] Unaudited Pro Forma Financial Results Business Acquisition, Pro Forma Information [Table Text Block] Schedule of Properties Sold Disposal Groups, Including Discontinued Operations [Table Text Block] Organization, Consolidation and Presentation of Financial Statements [Abstract] Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Financial Information for Parent Guarantor, Issuer Subsidiary and Non-Guarantor Subsidiaries Financial Information For Parent Issuer Guarantor Subsidiaries And Nonguarantor Subsidiaries [Text Block] Financial information for parent, issuer, guarantor subsidiaries, and nonguarantor subsidiaries. [Text Block] Scenario [Axis] Scenario [Axis] Scenario, Unspecified [Domain] Scenario, Unspecified [Domain] Forecast Scenario, Forecast [Member] Credit Facilities Line of Credit [Member] Mortgage Notes Mortgages [Member] $150 Million Term Loan $150 Million Term Loan, Maturity July 2022 [Member] $150 Million Term Loan, Maturity July 2022 [Member] Revolving Credit Facility JPMorgan Chase Credit Facility [Member] JPMorgan Chase Credit Facility [Member] 263 Shuman Boulevard building mortgage note Two-Hundred Sixty-Three Shuman Boulevard Mortgage Note [Member] Two-Hundred Sixty-Three Shuman Boulevard Mortgage Note [Member] One Glenlake mortgage note One Glenlake Building Mortgage Note [Member] One Glenlake Building Mortgage Note [Member] Less: Deferred financing costs related to term loans and notes payable, net of accumulated amortization Debt Issuance Costs, Net Gain on extinguishment of debt Interest expense Interest Expense, Debt Default interest rate Debt Instrument, Interest Rate During Period Net operating income (loss) including unconsolidated joint venture Net Operating Income (Loss) Including Unconsolidated Joint Venture Net Operating Income (Loss) Including Unconsolidated Joint Venture Supplemental Disclosures of Noncash Investing and Financing Activities Cash Flow, Supplemental Disclosures [Text Block] Asset and property management fees: Construction and Development Costs [Abstract] Related-party Asset And Property Management Fees Related Party The aggregate costs related to asset and property management during the reporting period paid to a related party. Other Depreciation Depreciation Continuing Operations The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives for continuing operations. Includes production and non-production related depreciation. Interest expense Gain on sales of real estate assets Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Buildings Building [Member] Building Improvements Building Improvements [Member] Intangible Below Market Lease Assets Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Estimated useful life of real estate assets Property, Plant and Equipment, Useful Life Gross intangible assets Amortization of intangible assets Hedge ineffectiveness recognized in earnings Gain (Loss) on Interest Rate Fair Value Hedge Ineffectiveness Requirement to distribute taxable income (at least) Requirement to Distribute Taxable Income, Percent Requirement to Distribute Taxable Income, Percent Limit on investments in taxable real estate investment trusts (percent) Limit on Investments in Taxable Real Estate Investment Trusts, Percent Limit on Investments in Taxable Real Estate Investment Trusts, Percent Cumulative-effect adjustment for the adoption of ASU Cumulative effect adjustment to equity Bonds Payable Bond Disclosure [Text Block] The entire disclosure for information about bonds, including repayment terms, interest rates, collateral provided, whether or not in compliance with covenants, and other matters important to users of the financial statements, such as the effects of refinancing and noncompliance with covenants. [Text Block] Summary of Financial Information for the Joint Ventures Equity Method Investments [Table Text Block] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Time-based Stock Awards Time-based Stock Awards [Member] Time-based Stock Awards [Member] RSUs Restricted Stock Units (RSUs) [Member] Equity Components [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] 2017 Stock Repurchase Program Twenty-Seventeen Stock Repurchase Program [Member] Twenty-Seventeen Stock Repurchase Program [Member] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] 2013 Long Term Incentive Plan 2013 Long Term Incentive Plan [Member] 2013 Long Term Incentive Plan [Member] Long Term Incentive Plan Long Term Incentive Plan [Member] Long Term Incentive Plan [Member] Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] End of Performance Period Share-based Compensation Award, Tranche Five [Member] Share-based Compensation Award, Tranche Five [Member] January 31, 2018 Share-based Compensation Award, Tranche Two [Member] January 31, 2019 Share-based Compensation Award, Tranche Three [Member] January 31, 2020 Share-based Compensation Award, Tranche Four [Member] Share-based Compensation Award, Tranche Four [Member] Stock repurchase program, authorized amount Stock Repurchase Program, Authorized Amount Common stock, par value (dollars per share) Common Stock, Par or Stated Value Per Share Number of shares repurchased (in shares) Stock Repurchased and Retired During Period, Shares Shares repurchased, average cost per share (dollars per share) Stock Repurchased And Retired During Period, Average Cost Per Share Stock Repurchased And Retired During Period, Average Cost Per Share Value of stock repurchased Stock Repurchased and Retired During Period, Value Stock repurchase program, amount available for repurchase Stock Repurchase Program, Remaining Authorized Repurchase Amount Shares authorized Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Award vesting rights (percent) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage Performance period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Payout percentage Share-based Compensation Arrangement by Share-based Payment Award, Performance Threshold, Payout Percentage Share-based Compensation Arrangement by Share-based Payment Award, Performance Threshold, Payout Percentage Unrecognized compensation costs related to unvested awards Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options Unrecognized compensation costs recognition period (years) Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Amortization of Intangible Lease Assets Intangible Below-Market In-Place Lease Liabilities Amortization of Below Market Lease Ownership percentage of wholly owned subsidiary Ownership Percentage, Wholly Owned Subsidiary Ownership Percentage, Wholly Owned Subsidiary Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Adjustments for Error Corrections [Axis] Adjustments for Error Corrections [Axis] Adjustments for Error Correction [Domain] Adjustments for Error Correction [Domain] Intercompany Cash Transfers Between Parent and Subsidiaries Broken Out by Cash Flow Type Intercompany Cash Transfers Between Parent and Subsidiaries Broken Out by Cash Flow Type [Member] Intercompany Cash Transfers Between Parent and Subsidiaries Are Now Broken Out by Cash Flow Type [Member] Restatement Adjustment Restatement Adjustment [Member] Parent Issuer Condensed Financial Statements, Captions [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Increase in operating cash flows Increase (decrease) in investing cash flows Increase (decrease) in financing cash flows Statement of Financial Position [Abstract] Bonds Payable Unsecured Debt [Member] Building and improvements, accumulated depreciation Real Estate Investment Property, Accumulated Depreciation Intangible lease assets, accumulated amortization Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable Intangible lease origination costs, accumulated amortization Deferred lease costs, accumulated amortization Deferred Costs, Leasing, Accumulated Amortization Deferred financing costs, net Bonds payable discount Debt Instrument, Unamortized Discount Intangible lease liabilities, accumulated amortization Off market lease, unfavorable, Accumulated Amortization The accumulated amount of amortization of off-market leases, unfavorable. Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Summary of the Activity of Employee Stock Grants Schedule of Nonvested Share Activity [Table Text Block] Summary of Shares Granted to Independent Directors Disclosure of Share-based Compensation Arrangements by Share-based Payment Award [Table Text Block] Schedule of Stock-based Compensation Expense Incurred Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Intangible Below-Market In-Place Lease Liabilities Below Market Lease [Abstract] For the remainder of 2018 Below Market Lease, Amortization Income, Remainder of Fiscal Year For the years ending December 31: Below Market Lease, Net, Amortization Income, Fiscal Year Maturity [Abstract] 2019 Below Market Lease, Amortization Income, Year Two 2020 Below Market Lease, Amortization Income, Year Three 2021 Below Market Lease, Amortization Income, Year Four 2021 Below Market Lease, Amortization Income, Year Five 2022 Below Market Lease, Amortization Income, Year Six Below Market Lease, Amortization Income, Year Six Thereafter Below Market Lease, Amortization Income, after Year Six Below Market Lease, Amortization Income, after Year Six Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Other property income Other Income [Member] Reimbursement revenue Reimbursement Revenue Property management fee receivable Property Management Fee Receivable Property Management Fee Receivable Line of Credit and Notes Payable Debt Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] 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 2026 Bonds Payable Two-Thousand and Twenty-Six Bonds Payable [Member] Two-Thousand and Twenty-Six Bonds Payable [Member] 2025 Bonds Payable Two-Thousand and Twenty-Five Bonds Payable [Member] Two-Thousand and Twenty-Five Bonds Payable 2026 and 2025 Bonds Payable Two-Thousand and Twenty-Six and Two-Thousand and Twenty-Five Bonds Payable [Member] Two-Thousand and Twenty-Six and Two-Thousand and Twenty-Five Bonds Payable [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 2 Fair Value, Inputs, Level 2 [Member] Number of series of bonds Number Of Series Of Bonds Number Of Series Of Bonds Maturity of debt instrument Debt Instrument, Term Interest rate for debt instrument (percent) Discount rate of face value of issued debt instrument (percent) Debt Instrument, Discount Rate at Issuance of Face Value Debt Instrument, Discount Rate at Issuance of Face Value Estimated fair value of debt instrument Real estate assets, at cost: Real Estate Investment Property, at Cost [Abstract] Buildings and improvements, less accumulated depreciation of $407,894 and $388,796, as of March 31, 2018 and December 31, 2017, respectively Intangible lease assets, less accumulated amortization of $99,092 and $94,065, as of March 31, 2018 and December 31, 2017, respectively Construction in progress Tenant receivables, net of allowance for doubtful accounts of $0 as of March 31, 2018 and December 31, 2017 Intangible lease origination costs, less accumulated amortization of $59,884 and $57,465, as of March 31, 2018 and December 31, 2017, respectively Deferred lease costs, less accumulated amortization of $28,562 and $26,464, as of March 31, 2018 and December 31, 2017, respectively Line of credit and notes payable, net of unamortized deferred financing costs of $2,641 and $2,991, as of March 31, 2018 and December 31, 2017, respectively Bonds payable, net of discounts of $1,439 and $1,484 and unamortized deferred financing costs of $4,607 and $4,760, as of March 31, 2018 and December 31, 2017, respectively Intangible lease liabilities, less accumulated amortization of $19,265 and $19,660, as of March 31, 2018 and December 31, 2017, respectively Commitments and Contingencies (Note 7) Commitments and Contingencies Common stock, $0.01 par value, 225,000,000 shares authorized, 118,601,872 and 119,789,106 shares issued and outstanding, as of March 31, 2018 and December 31, 2017, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Cumulative distributions in excess of earnings Accumulated Distributions in Excess of Net Income Cumulative other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total equity San Francisco Joint Ventures San Francisco Joint Ventures [Member] San Francisco Joint Ventures [Member] Carrying Value of Investment Equity Method Investments Additional ownership percentage acquired Equity Method Investment, Additional Ownership Percentage Acquired Equity Method Investment, Additional Ownership Percentage Acquired Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Previously granted awards, unvested Future period LTI Plan awards 2015 Long Term Incentive Plan [Member] 2015 Long Term Incentive Plan [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Distributions paid on unvested shares Preferred Stock Dividends and Other Adjustments Net income used to calculate basic and diluted earnings per share Net Income (Loss) Available to Common Stockholders, Basic Weighted-average common shares – basic Plus incremental weighted-average shares from time-vested conversions, less assumed share repurchases Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Weighted-average common shares – diluted Basis of Presentation Consolidation, Policy [Policy Text Block] Fair Value Measurements Fair Value of Financial Instruments, Policy [Policy Text Block] Real Estate Assets Property, Plant and Equipment, Policy [Policy Text Block] Assets Held for Sale Real Estate Held for Development and Sale, Policy [Policy Text Block] Evaluating the Recoverability of Real Estate Assets Impairment or Disposal of Long-Lived Assets, Including Intangible Assets, Policy [Policy Text Block] Intangible Assets and Liabilities Arising From In-Place Leases Where Columbia Property Trust Is the Lessor Lessor, Leases [Policy Text Block] Intangible Assets and Liabilities Arising From In-Place Leases Where Columbia Property Trust Is the Lessee Lessee, Leases [Policy Text Block] Interest Rate Swap Agreements Derivatives, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Reclassification Reclassification, Policy [Policy Text Block] Recent Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Loss Contingencies [Table] Loss Contingencies [Table] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Number of tenants that have exercised the option to expand property Lease Agreements, Number of Tenants That Have Exercised the Option to Expand Property Lease Agreements, Number of Tenants That Have Exercised the Option to Expand Property Additional Paid-In Capital Additional Paid-in Capital [Member] Cumulative Distributions in Excess of Earnings Accumulated Distributions in Excess of Net Income [Member] Cumulative Other Comprehensive Income AOCI Attributable to Parent [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning balance, shares Beginning balance, value Repurchases of common stock, shares Repurchases of common stock Common stock issued to employees and directors, and amortized (net of income tax withholdings), shares Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Common stock issued to employees and directors, and amortized (net of income tax withholdings) Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Distributions to common stockholders ($0.20 in 2018 and $0.20 in 2017) Dividends Ending balance, shares Ending balance, value Schedule of Real Estate Properties [Table] Schedule of Real Estate Properties [Table] Real Estate Property Ownership [Axis] Real Estate Property Ownership [Axis] Real Estate Properties [Domain] Real Estate Properties [Domain] Wholly Owned Properties Wholly Owned Properties [Member] Unconsolidated Properties Unconsolidated Properties [Member] Real Estate Properties [Line Items] Real Estate Properties [Line Items] Number of real estate properties Number of Real Estate Properties Number of properties under development Number Of Real Estate Properties Under Development Number Of Real Estate Properties Under Development Percent of leased office space of owned properties Leased Office Space of Owned Properties, Percent Leased Office Space of Owned Properties, Percent Bridge loan Bridge Loan Gross proceeds from sale of real estate Proceeds from Sale of Real Estate Held-for-investment, Gross Proceeds from Sale of Real Estate Held-for-investment, Gross Accruing note receivable as a result of the disposal Disposal Group, Including Discontinued Operation, Consideration, Note Receivable Disposal Group, Including Discontinued Operation, Consideration, Note Receivable Term of accruing note receivable as a result of the disposal Disposal Group, Including Discontinued Operation, Consideration, Note Receivable, Term Disposal Group, Including Discontinued Operation, Consideration, Note Receivable, Term Deferred gain on disposal Disposal Group, Deferred Gain on Disposal Gain on sale Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal Loss from disposal group Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Summary of Significant Accounting Policies Basis of Presentation and Significant Accounting Policies [Text Block] Schedule of Basic and Diluted Earnings Per Share Computations Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Condensed Consolidating Balance Sheets Condensed Balance Sheet [Table Text Block] Consolidating Statements of Operations Condensed Income Statement [Table Text Block] Consolidating Statements of Comprehensive Income Comprehensive Income (Loss) [Table Text Block] Consolidating Statements of Cash Flows Condensed Cash Flow Statement [Table Text Block]