Income Statement [Abstract] Statement [Table] Statement [Table] Legal Entity [Axis] Entity [Domain] Statement [Line Items] Statement [Line Items] Revenues: Revenues [Abstract] Rental income Operating Leases, Income Statement, Lease Revenue Tenant reimbursements Tenant Reimbursements Property management fee revenue Management Fees Revenue Other rental income Gain (Loss) on Contract Termination Total revenues Revenues Expenses: Operating Expenses [Abstract] Property operating costs Direct Costs of Leased and Rented Property or Equipment 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, from continuing operations. 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, from continuing operations. General and administrative General and Administrative Expense Operating Expenses Operating Expenses Real estate operating income Operating Income (Loss) Other income (expense): Nonoperating Income (Expense) [Abstract] Interest expense Interest Expense Interest and other (expense)/income Other Nonoperating Income Equity in income of unconsolidated joint ventures Income (Loss) from Equity Method Investments Gain on consolidation of variable interest entity Variable Interest Entity, Initial Consolidation, Gain (Loss) Nonoperating Income (Expense) Nonoperating Income (Expense) Income from continuing operations Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Discontinued operations: Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent [Abstract] Operating income Disposal Group, Including Discontinued Operation, Operating Income (Loss) Impairment loss Disposal Group, Including Discontinued Operation, Loss on Write Down Disposal Group Including Discontinued Operation Loss on Write Down Gain on sale of real estate assets Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Income from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Less: Net income attributable to noncontrolling interest Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest Net income attributable to Piedmont Net Income (Loss) Attributable to Parent Per share information – basic: Earnings Per Share, Basic [Abstract] Income from continuing operations Income (Loss) from Continuing Operations, Per Basic Share Income from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Per Basic Share Net income available to common stockholders Earnings Per Share, Basic Per share information – diluted: Earnings Per Share, Diluted [Abstract] Income from continuing operations Income (Loss) from Continuing Operations, Per Diluted Share Income from discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Per Diluted Share Net income available to common stockholders Earnings Per Share, Diluted Weighted-average common shares outstanding - basic (in shares) Weighted Average Number of Shares Outstanding, Basic Weighted-average common shares outstanding - diluted (in shares) Weighted Average Number of Shares Outstanding, Diluted Derivative Instruments [Abstract] Derivative Instruments [Abstract] Derivative [Table] Derivative [Table] Long-term and Short-term Debt, Type [Axis] Long-term and Short-term Debt, Type [Axis] Long-term and Short-term Debt, Type [Domain] Long-term and Short-term Debt, Type [Domain] Unsecured Debt [Member] Secured Debt [Member] Debt Instrument [Axis] Debt Instrument, Name [Domain] Unsecured $250 Million Term Loan [Member] Unsecured 250Million Term Loan [Member] Unsecured 250Million Term Loan [Member] 500 W. Monroe Mezzanine I Loan- A Participation $45 Million [Member] Mezzanine I Loan-A Participation, 500 W. Monroe Building [Member] W. Monroe, 500 Mezzanine I Loan-A Participation [Member] Derivative Instruments, Gain (Loss) by Income Statement Location [Axis] Interest Expense [Member] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] Interest Rate Contract [Member] Interest Rate Swap [Member] Interest Rate Cap [Member] Interest Rate Cap 1 [Member] Interest Rate Cap 1 [Member] Interest Rate Cap 2 [Member] Interest Rate Cap 2 [Member] Derivative [Line Items] Derivative [Line Items] Debt Instrument, Face Amount Debt Instrument, Face Amount Notional Amount Notional Amount of Interest Rate Cash Flow Hedge Derivatives Amount of loss recognized in OCI on derivative Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss) Amount of previously recorded loss reclassified from accumulated OCI into interest expense Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Interest rate swap Interest Rate Cash Flow Hedge Liability at Fair Value Interest Rate Fair Value Hedge Derivative at Fair Value, Net Interest Rate Fair Value Hedge Derivative at Fair Value, Net Number of Interest Rate Derivatives Held Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments Line of Credit and Notes Payable [Abstract] Line of Credit and Notes Payable [Abstract] Line of Credit and Notes Payable Debt Disclosure [Text Block] Schedule of Debt Instruments [Table] Schedule of Debt Instruments [Table] Schedule of Debt Instruments [Table] Range [Axis] Range [Domain] Minimum [Member] Maximum [Member] Fixed-Rate $45 Million Loan [Member] Fixed-Rate 45Million Loan [Member] Fixed-Rate 45Million Loan [Member] Mortgage Note $200 Million [Member] Aon Center Chicago 4.87 Mortgage Note [Member] Aon Center Chicago 4.87 Mortgage Note [Member] Mortgage Note $25 Million [Member] Aon Center Chicago 5.70 Mortgage Note [Member] Aon Center Chicago 5.70 Mortgage Note [Member] Secured Pooled Facility [Member] Secured Pooled Facility [Member] Fixed-Rate $105 Million Loan [Member] Fixed-Rate 105Million Loan [Member] Fixed-Rate 105Million Loan [Member] Fixed-Rate $125 Million Loan [Member] Fixed-Rate 125Million Loan [Member] Fixed-Rate 125Million Loan [Member] Fixed-Rate $42.5 Million Loan [Member] Fixed-Rate 42.5Million Loan [Member] Fixed-Rate 42.5Million Loan [Member] WDC Mortgage Notes $140 Million[Member] WDC Mortgage Notes [Member] WDC Mortgage Notes [Member] 500 W. Monroe Mortgage Loan $140 Million [Member] Mortgage Loan, 500 W. Monroe Building [Member] W. Monroe, 500 Mortgage Loan [Member] Unsecured $500 Million Facility [Member] Unsecured 500Million Facility [Member] Unsecured 500Million Facility [Member] Debt Instrument [Line Items] Line Of Credit Facility Extension Period Line Of Credit Facility Extension Period Interest Payments on Debt Facilities Interest Paid, Net Rate Debt Instrument, Interest Rate, Stated Percentage Debt, Weighted Average Interest Rate Debt, Weighted Average Interest Rate Debt Weighted Average Interest Rate Excluding Discontinued Operation Debt Weighted Average Interest Rate Excluding Discontinued Operation Reflects the calculation as of the balance sheet date, excluding notes payable held for sale, of the average interest rate weighted by the amount of secured debt outstanding by type or by instrument at that time. Line of credit and notes payable, outstanding Notes and Loans Payable Derivative, Cap Interest Rate Derivative, Cap Interest Rate Debt Instrument, Basis Spread on Variable Rate Debt Instrument, Basis Spread on Variable Rate LIBOR Interest Rate In Effect LIBOR Interest Rate In Effect LIBOR Interest Rate In Effect Debt Instrument, Description of Variable Rate Basis Prime Rate In Effect Prime Rate In Effect Company-specific short term borrowing rate. Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Commitments and Contingencies [Abstract] Commitments and Contingencies Abstract Schedule of Letters of Credit Schedule of Letters of Credit [Table Text Block] Schedule of Letters of Credit [Table Text Block] Earnings Per Share [Abstract] Weighted-average common shares – basic (in shares) Restricted stock awards Incremental Common Shares Attributable to Share-based Payment Arrangements Weighted-average common shares – diluted (in shares) Fair Value Measurement of Financial Instruments [Abstract] Fair Value Measurement of Financial Instruments [Abstract] Fair Value Measurement of Financial Instruments Fair Value Disclosures [Text Block] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Organization [Abstract] Organization Abstract Schedule of Real Estate Properties [Table] Schedule of Real Estate Properties [Table] Real Estate Properties By Type [Axis] Real Estate Properties By Type [Axis] Real Estate Properties Type [Domain] Real Estate Properties Type [Domain] Office properties [Member] Office properties [Member] Building [Member] Industrial buildings [Member] Industrial buildings [Member] Joint Venture [Member] Joint Venture [Member] Real Estate Properties [Line Items] Real Estate Properties [Line Items] Number Of Wholly Owned Subsidiaries Number Of Wholly Owned Management Subsidiaries Number Of Wholly Owned Management Subsidiaries Number of Real Estate Properties Number of Real Estate Properties Number of Metropolitan Areas Number of Metropolitan Areas In Which Entity Operates Number of Metropolitan Areas In Which Entity Operates Square Footage of Real Estate Property Square Footage of Real Estate Property Real Estate Properties Leased, Percent Real Estate Properties Leased, Percent Real Estate Properties Leased Percent Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Acquisitions [Abstract] Acquisitions [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] 1200 Enclave Parkway Building [Member] Enclave Parkway Building, 1200 [Member] 1200 Enclave Parkway Building [Member] The Dupree Building [Member] The Dupree Building [Member] The Medici Building [Member] The Medici Building [Member] The 225 and 235 Presidential Way Buildings Presidential Way Buildings 225 And 235 [Member] Presidential Way Buildings 225 And 235 [Member] 500 W. Monroe Building [Member] W. Monroe Building, 500 [Member] W. Monroe Building, 500 [Member] Business Acquisition [Line Items] Number of Buildings Number Of Buildings In Real Estate Properties Number Of Buildings In Real Estate Properties Rentable Square Feet Percentage Occupied as of Acquisition Date Acquisition Price Business Acquisition, Cost of Acquired Entity, Purchase Price Statement of Financial Position [Abstract] Assets: Assets [Abstract] Land Land Buildings and improvements, less accumulated depreciation of $766,163 and $707,314 as of September 30, 2011 and December 31, 2010, respectively Investment Building and Building Improvements, Net Investment Building and Building Improvements, Net Intangible lease assets, less accumulated amortization of $118,574 and $125,193 as of September 30, 2011 and December 31, 2010, respectively Finite-Lived Intangible Assets, Net Construction in progress Construction in Progress, Gross Real estate assets held for sale, net Real Estate Held-for-sale Total real estate assets Real Estate Investment Property, Net Investments in unconsolidated joint ventures Equity Method Investments Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Tenant receivables, net of allowance for doubtful accounts of $809 and $1,298 as of September 30, 2011 and December 31, 2010, respectively Accounts Receivable, Net Notes receivable Notes, Loans and Financing Receivable, Net Due from unconsolidated joint ventures Due from Joint Ventures Restricted cash and escrows Restricted Cash and Cash Equivalents Prepaid expenses and other assets Prepaid Expense and Other Assets Goodwill Goodwill Deferred financing costs, less accumulated amortization of $8,611 and $11,740 as of September 30, 2011 and December 31, 2010, respectively Deferred Finance Costs, Net Deferred lease costs, less accumulated amortization of $115,633 and $111,671 as of September 30, 2011 and December 31, 2010, respectively Deferred Costs, Leasing, Net Other assets held for sale Disposal Group, Including Discontinued Operation, Other Assets Total assets Assets Liabilities: Liabilities [Abstract] Line of credit and notes payable Notes Payable Accounts payable, accrued expenses, and accrued capital expenditures Accounts Payable and Accrued Liabilities Deferred income Deferred Revenue Intangible lease liabilities, less accumulated amortization of $65,496 and $60,850 as of September 30, 2011 and December 31, 2010, respectively Off-market Lease, Unfavorable Notes payable and other liabilities held for sale Liabilities of Assets Held-for-sale Total liabilities Liabilities Commitments and Contingencies Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Shares-in-trust, 150,000,000 shares authorized; none outstanding as of September 30, 2011 or December 31, 2010 Common Stock Held in Trust Preferred stock, no par value, 100,000,000 shares authorized; none outstanding as of September 30, 2011 or December 31, 2010 Preferred Stock, Value, Issued Common stock, $.01 par value, 750,000,000 shares authorized; 172,826,991 and 172,658,489 shares issued and outstanding as of September 30, 2011 and December 31, 2010, respectively (Note 12) 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 Other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Piedmont stockholders' equity Stockholders' Equity Attributable to Parent Noncontrolling interest Stockholders' Equity Attributable to Noncontrolling Interest Noncontrolling interest held for sale Noncontrolling Interest Held For Sale Noncontrolling Interest Held For Sale Total stockholders' equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and stockholders' equity Liabilities and Equity Variable Interest Entities [Abstract] Variable Interest Entities [Abstract] Schedule of Variable Interest Entities [Table] Schedule of Variable Interest Entities [Table] Variable Interest Entities by Classification of Entity [Axis] Variable Interest Entities by Classification of Entity [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Primary Beneficiary [Member] Eye Street 1201 NW Associates LLC [Member] Eye Street 1201 NW Associates LLC [Member] Eye Street 1225 NW Associates LLC [Member] Eye Street 1225 NW Associates LLC [Member] Piedmont 500 W. Monroe Fee LLC [Member] Piedmont 500 W. Monroe Fee LLC [Member] Suwanee Gateway One LLC [Member] Suwanee Gateway One LLC [Member] Medici Atlanta LLC [Member] Medici Atlanta LLC [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Net Carrying Amount Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net Piedmont’s % Ownership of Entity Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Variable Interst Entity, Cash Flow Percent Entitled To Entity Variable Interst Entity Cash Flow Percent Entitled To Entity Variable Interst Entity Cash Flow Percent Entitled To Entity Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Accounting Policies [Abstract] Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Schedule of Business Acquisitions, by Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Loss Contingencies [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] W Wacker Building 35 [Member] W Wacker Building 35 [Member] Letter of Credit Agreements by Expiration Date [Axis] Letter of Credit Agreements by Expiration Date [Axis] Letter of Credit Agreements by Expiration Date [Domain] Letter of Credit Agreements by Expiration Date [Domain] Letter Of Credit August 2012 [Member] Letter Of Credit August 2012 [Member] Letter of Credit 2, February 2012 [Member] Letter of Credit 2, February 2012 [Member] Letter of Credit, December 2011 [Member] Letter of Credit, December 2011 [Member] Letter of Credit, December 2011 [Member] Letter Of Credit, June 2012 [Member] Letter Of Credit June 2012 [Member] Letter Of Credit June 2012 [Member] Loss Contingencies by Nature of Contingency [Axis] Loss Contingency, Nature [Domain] Collectibility of Tenant Reimbursements [Member] Collectibility of Tenant Reimbursements [Member] Loss Contingencies [Line Items] Commitment to Provide Funding to Tenants for Capital Improvements Commitment to Provide Funding to Tenants for Capital Improvements Commitment to Provide Funding to Tenants for Capital Improvements Commitment To Provide Funding To Tenants For Capital Improvements Period Commitment To Provide Funding To Tenants For Capital Improvements Period Loss Contingency Accrual, Carrying Value, Provision Loss Contingency Accrual, Carrying Value, Provision Loss Contingency Recovery Loss Contingency Recovery Loss Contingency Recovery Letters of Credit Outstanding, Amount Letters of Credit Outstanding, Amount Number of Lawsuits as Defendant Number of Lawsuits as Defendant Letter of Credit Renewal Period Letter of Credit Renewal Period Stock Based Compensation [Abstract] Stock Based Compensation [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] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain] Stock Awards [Member] Stock Awards [Member] Stock Awards, Granted May 6, 2009 [Member] Stock Awards, Granted May 6, 2009 [Member] Stock Awards 1, Granted May 24, 2010 [Member] Stock Awards 1, Granted May 24, 2010 [Member] Stock Awards 2, Granted May 24, 2010 [Member] Stock Awards 2, Granted May 24, 2010 [Member] Stock Awards, Granted April 5, 2011 [Member] Stock Awards, Granted April 5, 2011 [Member] Report Date [Axis] Financial Statements Date [Domain] Date 2011-06-30 [Member] Date 2011-06-30 [Member] Date 2011-09-30 [Member] Date20110930 [Member] Date 2011-09-30 [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Allocated Share-based Compensation Expense Allocated Share-based Compensation Expense Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Amortization Of Nonvested Shares Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Amortization Of Nonvested Shares Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Amortization Of Nonvested Shares Net Shares Granted Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Grants Net On Reported Date Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Grants, Net, On Reported Date Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Unvested Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Of the shares granted, % vested Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Vested Percent At Reported Date Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Vested Percent At Reported Date Of the shares granted, % expected to vest Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Expected To Vest Percent At Reported Date Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected To Vest Percent At Reported Date Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Financing [Member] Financing [Member] Dividend Declared [Member] Dividend Declared [Member] Discontinued Operation or Asset Disposal [Member] Discontinued Operation or Asset Disposal [Member] Acquisition [Member] Stock Repurchase Program [Member] Stock Repurchase Program [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Percent of Ownership Interest In Real Estate Property Disposal Percent of Ownership Interest In Real Estate Property Disposal Percent of Ownership Interest In Real Estate Property Disposal Real Estate Property Disposal, Sale Price Real Estate Property Disposal Sale Price Real Estate Property Disposal, Sale Price Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Stock Repurchase Program, Authorized Amount Schedule of Nonvested Share Activity Schedule of Nonvested Share Activity [Table Text Block] Acquisitions Business Combination Disclosure [Text Block] Statement of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Operating distributions received from unconsolidated joint ventures Equity Method Investment, Dividends or Distributions 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] Income attributable to noncontrolling interest- discontinued operations Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest Depreciation Depreciation Amortization of deferred financing costs, fair market value adjustments on notes payable, and interest rate cap agreements Amortization of Financing Costs Other amortization Amortization of Intangible Assets Impairment loss Accretion of notes receivable discount Accretion (Amortization) of Discounts and Premiums, Investments Stock compensation expense Share-based Compensation Equity in income of unconsolidated joint ventures Gain on sale of real estate assets Gain on consolidation of variable interest entity Changes in assets and liabilities: Increase (Decrease) in Operating Assets [Abstract] Increase in tenant receivables, net Increase (Decrease) in Accounts Receivable Increase in restricted cash and escrows Increase (Decrease) in Restricted Cash for Operating Activities Increase in prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Increase 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 Net Cash Provided by (Used in) Operating Activities Cash Flows from Investing Activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Investments in real estate assets and related intangibles Payments to Acquire Productive Assets Cash assumed upon consolidation of variable interest entity Assets Assumed Upon Consolidation Of Variable Interest Entity Net assets received as cash upon consolidation of a variable interest entity ("VIE"). Net sales proceeds from wholly-owned properties Proceeds from Divestiture of Businesses, Net of Cash Divested Net sales proceeds received from unconsolidated joint ventures Proceeds from Sale of Equity Method Investments Investments in unconsolidated joint ventures Payments to Acquire Equity Method Investments Deferred lease costs paid Increase (Decrease) in Lease Acquisition Costs 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] Deferred financing costs paid Payments of Financing Costs Proceeds from line of credit and notes payable Proceeds from Notes Payable Repayments of line of credit and notes payable Repayments of Notes Payable Net proceeds from issuance of common stock Proceeds from Issuance of Common Stock Redemption of fractional shares of common stock Payments for Repurchase of Common Stock Dividends paid and discount on dividend reinvestments Payments of Dividends Common Stock and Discount on Dividend Reinvestments Sum of a) The cash outflow from the distribution of an entity's earnings in the form of dividends to common shareholders, and b) Discount on dividend reinvestments. Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Net (decrease)/increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents, beginning of period Cash and cash equivalents, end of period Supplemental Disclosures of Significant Noncash Investing and Financing Activities: Supplemental Cash Flow Information [Abstract] Change in accrued offering costs Increase (Decrease) in Deferred Offering Costs Change in specific incremental costs directly attributable to a proposed or actual offering of securities which are deferred at the end of the reporting period. Accrued capital expenditures and deferred lease costs Increase Decrease In Accrued Capital Expenditures AndDeferred Lease Costs Net change in the balance of accrued lease acquisition costs and accrued capital expenditures during the period. These accrued costs consist of items such as leasing commissions, lease incentives, procurement fees, tenant improvements, and/or general building improvements. Net assets assumed upon consolidation of variable interest entity, net of notes receivable previously recorded Net Assets Assumed Upon Consolidation Of Variable Interest Entity, Net Of Notes Receivable Previously Recorded Net Assets within a variable interest entity ("VIE") structure assumed at estimated fair market value, net of notes receivable previously recorded. Liabilities assumed upon consolidation of variable interest entity Liabilities Assumed Upon Consolidation Of Variable Interest Entity Liabilities within a variable interest entity ("VIE") structure assumed at estimated fair market value. Redeemable common stock Redeemable Common Stock Value Change in redeemable common stock value during the period. Notes Receivable [Abstract] Notes Receivable [Abstract] Notes Receivable Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Fair Value, by Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Table Text Block] Variable Interest Entities Variable Interest Entity, Similar Entity Aggregation, Description Schedule of Debt Schedule of Debt [Table Text Block] Earnings Per Share Earnings Per Share [Text Block] Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis] Fair Value, Disclosure Item Amounts [Domain] Fair Value, Disclosure Item Amounts [Domain] Carrying (Reported) Amount, Fair Value Disclosure [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member] Estimate of Fair Value, Fair Value Disclosure [Member] Estimate of Fair Value, Fair Value Disclosure [Member] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Tenant receivables, net Receivables, Fair Value Disclosure Accounts Payable Accounts Payable, Fair Value Disclosure Interest rate swap agreements Line of credit and notes payable Notes Payable, Fair Value Disclosure Income Tax For Real Estate Investment Trusts [Table] Income Tax For Real Estate Investment Trusts [Table] Income Tax For Real Estate Investment Trusts [Table] Income Tax For Real Estate Investment Trusts [Line Items] Income Tax For Real Estate Investment Trusts [Line Items] Real Estate Investment Trust Status Required Taxable Income Distribution Rate Real Estate Investment Trust Status Required Taxable Income Distribution Rate Real Estate Investment Trust Status Required Taxable Income Distribution Rate Schedule of Notional Amounts of Outstanding Derivative Positions Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss) [Table Text Block] Discontinued Operations [Abstract] Discontinued Operations [Abstract] Disclosure of Long Lived Assets Held-for-sale Disclosure of Long Lived Assets Held-for-sale [Table Text Block] Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block] Income Tax, Policy Income Tax, Policy [Policy Text Block] Derivatives, Methods of Accounting, Hedging Derivatives Derivatives, Methods of Accounting, Hedging Derivatives [Policy Text Block] Stock Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Document and Entity Information [Abstract] Document and Entity Information [Abstract] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Schedule of Weighted Average Number of Shares Schedule of Weighted Average Number of Shares [Table Text Block] Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Notes Receivable and Variable Interest Entity [Table] Notes Receivable and Variable Interest Entity [Table] Notes Receivable and Variable Interest Entity [Table] Mezzanine I Loan-A Participation, 500 W. Monroe Building [Member] Component of Other Income, Nonoperating [Axis] Component of Other Income, Nonoperating, Name [Domain] Operating Cash Flow On Foreclosed Property [Member] Operating Cash Flow On Foreclosed Property [Member] Variable Interest Entity, Initial Consolidation, Gain (Loss) Number of Investments Number of Investments Number of Notes Receivable Matured Number of Notes Receivable Matured Number of Notes Receivable Number of Notes Receivable Other Nonoperating Income Statement of Stockholders' Equity [Abstract] Statement, Equity Components [Axis] Statement, Equity Components [Axis] Equity Component [Domain] Common Stock [Member] Additional Paid-In Capital [Member] Additional Paid-in Capital [Member] Cumulative Distributions in Excess of Earnings [Member] Retained Earnings [Member] Redeemable Common Stock [Member] Redeemable Common Stock [Member] Redeemable Common Stock [Member] Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income (Loss) [Member] Non-controlling Interest [Member] Noncontrolling Interest [Member] Balance, shares Common Stock, Shares, Outstanding Balance, value Offering costs associated with issuance of common stock Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Net proceeds from issuance of common stock, shares Stock Issued During Period, Shares, New Issues Net proceeds from issuance of common stock, value Stock Issued During Period, Value, New Issues Redemption of fractional shares of common stock, shares Stock Redeemed or Called During Period, Shares Redemption of fractional shares of common stock, value Stock Redeemed or Called During Period, Value Change in redeemable common stock outstanding Additional Paid In Capital, Change In Redeemable Common Stock Outstanding The change in the value reclassified as Redeemable Common Stock. Dividends to common stockholders ($1.26 (YTD 2010) and $0.945 (YTD 2011) per share), distributions to noncontrolling interest, and dividends reinvested Dividends, Minority Interest (Decrease) From Distributions to Noncontrolling Interest Holders and Stock Issued During Period Value Dividend Reinvestment Plan Sum of a) Equity impact of aggregate cash, stock, and paid-in-kind dividends declared for all securities (common shares, preferred shares, etc.) during the period, b) Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders, and c) Value of stock issued during the period from a dividend reinvestment plan (DRP). A dividend reinvestment plan allows the holder of the stock to reinvest dividends paid to them by the entity on new issues of stock by the entity. Shares issued under the 2007 Omnibus Incentive Plan, net of tax, shares Shares issued under the 2007 Omnibus Incentive Plan, net of tax, value Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Net income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Components of comprehensive income: Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Net income Net change in interest rate swap/derivatives Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Balance, value Balance, shares Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] Eastpointe Corporate Center [Member] Eastpointe Corporate Center [Member] Corporate Court 5000 [Member] Corporate Court 5000 [Member] Mortgage Note, 35 West Wacker Building [Member] Mortgage Note, 35 West Wacker Building [Member] Long Lived Assets Held-for-sale by Asset Type [Axis] Long Lived Assets Held-for-sale, Name [Domain] Land [Member] Building Improvements [Member] Construction in Progress [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] Real estate assets held for sale, net: Real Estate Held for Development and Sale, Net [Abstract] Property, Plant, and Equipment, Net Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net Property, Plant, and Equipment, Accumulated Depreciation Disposal Group, Including Discontinued Operation, Accumulated Depreciation, Property Plant and Equipment Disposal Group, Including Discontinued Operation, Accumulated Depreciation, Property Plant and Equipment Intangible lease assets Disposal Group, Including Discontinued Operation, Intangible Assets, Net Intangible lease assets, accumulated amortization Disposal Group Including Discontinued Operation Finite Lived Intangible Assets Accumulated Amortization Disposal Group Including Discontinued Operation Finite Lived Intangible Assets Accumulated Amortization Other assets held for sale: Other Assets Held For Sale [Abstract] Other assets held for sale [Abstract] Tenant receivables Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net Deferred financing costs, net Disposal Group Including Discontinued Operation Deferred Financing Costs Net Disposal Group Including Discontinued Operation Deferred Financing Costs Net Deferred financing costs, accumulated amortization Disposal Group Including Discontinued Operation Deferred Financing Costs Accumulated Amortization Disposal Group Including Discontinued Operation Deferred Financing Costs Accumulated Amortization Deferred lease costs, net Disposal Group Including Discontinued Operation Deferred Lease Costs Net Disposal Group Including Discontinued Operation Deferred Lease Costs Net Deferred lease costs, accumulated amortization Disposal Group, Including Discontinued Operation, Deferred Lease Costs, Accumulated Amortization Disposal Group, Including Discontinued Operation, Deferred Lease Costs, Accumulated Amortization Restricted cash and escrows Disposal Group Including Discontinued Operation Restricted Cash And Escrows For the disposal group, including a component of the entity (discontinued operation), restricted cash and escrows. Other assets held for sale Notes payable and other liabilities held for sale: Notes payable And Other Liabilities Held For Sale [Abstract] Notes payable and other liabilities held for sale [Abstract] Notes payable Disposal Group, Including Discontinued Operation, Other Liabilities Notes payable, interest rate Notes payable, maturity date Debt Instrument, Maturity Date Intangible lease liabilities, less accumulated amortization of $25,960 and $23,458 as of September 30, 2011 and December 31, 2010, respectively Disposal Group Including Discontinued Operation Off Market Lease Unfavorable For the disposal group, including a component of the entity (discontinued operation), a liability associated with the acquisition of an off-market lease when the terms of the lease are unfavorable to the market terms of the lease at the date of the acquisition. Intangible lease liabilities, less accumulated amortization Disposal Group Including Discontinued Operation Intangible Lease Liabilities Accumulated Amortization For disposal group, including discontinued operation, accumulated amortization on intangible lease liabilities. Total notes payable and other liabilities held for sale Rental Income Disposal Group, Including Discontinued Operation, Rental Income Disposal Group, Including Discontinued Operation, Rental Income Tenant Reimbursement Disposal Group, Including Discontinued Operation, Tenant Reimbursement Disposal Group, Including Discontinued Operation, Tenant Reimbursement Revenue Disposal Group, Including Discontinued Operation, Revenue Expenses: Expenses [Abstract] Expenses [Abstract] Property Operating Costs Disposal Group, Including Discontinued Operation, Property Operating Costs Disposal Group, Including Discontinued Operation, Property Operating Costs Depreciation Disposal Group, Including Discontinued Operation, Depreciation Disposal Group, Including Discontinued Operation, Depreciation Amortization of deferred leasing costs Disposal Group, Including Discontinued Operation, Amortization Disposal Group, Including Discontinued Operation, Amortization General and administrative expense Disposal Group, Including Discontinued Operation, General and Administrative Expense Disposal Group, Including Discontinued Operation, General and Administrative Expense Expenses Disposal Group, Including Discontinued Operation, Operating Expense Other income (expense): Other Income and Expenses [Abstract] Interest expense Disposal Group, Including Discontinued Operation, Interest Expense Interest and other income Disposal Group Including Discontinued Operation Interest And Other Income Expense Disposal Group Including Discontinued Operation Interest And Other Income Expense Net income attributable to noncontrolling interest Other income (expense) Disposal Group Including Discontinued Other Income Expense Disposal Group Including Discontinued Other Income Expense Operating income, excluding impairment loss and gain on sale Income from discontinued operations Dividends to common stockholders per share Consolidated Balance Sheets Parenthetical [Abstract] Consolidated Balance Sheets Parenthetical [Abstract] Property, Plant and Equipment by Type [Axis] Property, Plant and Equipment, Type [Domain] Building and Building Improvements [Member] Assets: Real Estate Investment Property, Accumulated Depreciation Real Estate Investment Property, Accumulated Depreciation Intangible lease assets, accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Tenant receivables, allowance for doubtful accounts Allowance for Doubtful Accounts Receivable Deferred financing costs, accumulated amortization Accumulated Amortization, Deferred Finance Costs Deferred lease costs, accumulated amortization Deferred Costs, Leasing, Accumulated Amortization Intangible lease liabilities, accumulated amortization Intangible Lease Liabilities, Accumulated Amortization The amount of accumulated amortization related to unfavorable real estate leases. Shares-in-trust, shares authorized (in shares) Shares In Trust Authorized Shares In Trust Authorized Shares-in-trust, shares outstanding (in shares) Shares In Trust Outstanding Shares In Trust Outstanding Preferred stock, par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Preferred stock, shares authorized (in shares) Preferred Stock, Shares Authorized Preferred stock, shares outstanding (in shares) Preferred Stock, Shares Outstanding Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares outstanding (in shares)