Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Arlington Gateway [Member] Arlington Gateway [Member] Arlington Gateway [Member] Wayside, 5 and 15 [Member] Wayside Road, 5 and 15 [Member] Wayside Road, 5 and 15 [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Rentable Square Feet Area of Real Estate Property Percentage Leased as of Acquisition Percentage of Leased Real Estate Properties Percentage of Leased Real Estate Properties Purchase Price Business Acquisition, Cost of Acquired Entity, Purchase Price 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] Legal Entity [Axis] Entity [Domain] Unconsolidated Joint Venture [Member] Unconsolidated 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 Derivative Instruments [Abstract] Derivative Instruments [Abstract] Derivative [Table] Derivative [Table] Derivative, by Nature [Axis] Derivative, by Nature [Axis] Derivative, Name [Domain] Derivative, Name [Domain] Debt [Member] Debt [Member] 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] Debt Instrument [Axis] Debt Instrument, Name [Domain] $300 Million Unsecured Term Loan [Member] Unsecured 300 Million Term Loan [Member] $300 Million Unsecured Term Loan [Member] Income Statement Location [Axis] Income Statement and Other Comprehensive Income (Loss) Location [Domain] Income Statement Location [Domain] Interest Expense [Member] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] Interest Rate Swap [Member] Interest Rate Swap [Member] Interest Rate Swap 1 [Member] Interest Rate Swap 1 [Member] Interest Rate Swap 1 [Member] Interest Rate Swap 2 [Member] Interest Rate Swap 2 [Member] Interest Rate Swap 2 [Member] Interest Rate Swap 3 [Member] Interest Rate Swap 3 [Member] Interest Rate Swap 3 [Member] Interest Rate Swap 4 [Member] Interest Rate Swap 4 [Member] Interest Rate Swap 4 [Member] Interest Rate Swap 5 [Member] Interest Rate Swap 5 [Member] Interest Rate Swap 5 [Member] Interest Rate Swap 6 [Member] Interest Rate Swap 6 [Member] Credit Risk Contract [Member] Credit Risk Contract [Member] Derivative [Line Items] Derivative [Line Items] Face amount of debt instument Debt Instrument, Face Amount Notional Amount Notional Amount of Interest Rate Cash Flow Hedge Derivatives Derivative, term of contract Derivative, Term of Contract Derivative, Term of Contract Hedged amount associated with potential issuance of long-term debt Derivative, Amount of Hedged Item Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract] Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract] Interest rate swap Interest Rate Cash Flow Hedge Asset at Fair Value Interest rate swaps Interest Rate Cash Flow Hedge Liability at Fair Value Net derivative asset/(liability) Interest Rate Cash Flow Hedge Derivative at Fair Value, Net 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 Loss to be reclassified from accumulated other comprehensive loss to interest expense over next twelve months Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Gain (loss) recognized related to hedge ineffectiveness Gain (Loss) on Interest Rate Cash Flow Hedge Ineffectiveness Assets Needed for Immediate Settlement, Aggregate Fair Value Assets Needed for Immediate Settlement, Aggregate Fair Value Earnings Per Share [Abstract] Schedule of Weighted Average Number of Shares Schedule of Weighted Average Number of Shares [Table Text Block] Earnings Per Share Earnings Per Share [Text Block] Line of Credit and Notes Payable [Abstract] Line of Credit and Notes Payable [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term and Short-term Debt, Type [Axis] Long-term and Short-term Debt, Type [Domain] Unsecured Debt [Member] Debt Instrument [Axis] Debt Instrument, Name [Domain] $500 Million Unsecured Line of Credit [Member] Unsecured 500 Million Line of Credit [Member] Unsecured 500 Million Line of Credit [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Net borrowings Line of Credit Facility, Increase (Decrease) for Period, Net Borrowing capacity of line of credit Line of Credit Facility, Current Borrowing Capacity Interest payments on debt facilities Interest Paid, Net Receivables [Abstract] Schedule of Tenant Receivables Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Derivative Instruments Derivative Instruments and Hedging Activities Disclosure [Text Block] Discontinued Operations and Disposal Groups [Abstract] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Disposal Group Name [Axis] Disposal Group Name [Axis] Disposal Groups, Including Discontinued Operations, Name [Domain] Disposal Groups, Including Discontinued Operations, Name [Domain] 1200 Enclave Parkway [Member] ENCLAVE PARKWAY 1200 [Member] ENCLAVE PARKWAY 1200 [Member] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Land [Member] Land [Member] Building and Building Improvements [Member] Building and Building Improvements [Member] Construction in progress [Member] Construction in Progress [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Real estate assets held for sale Disposal Group, Including Discontinued Operation, Property, Plant, and Equipment, Net Accumulated depreciation (building improvements) Disposal Group, Including Discontinued Operation, Accumulated Depreciation, Property Plant and Equipment Disposal Group, Including Discontinued Operation, Accumulated Depreciation, Property Plant and Equipment Straight-line rent Disposal Group, Including Discontinued Operation, Straight-line Rent Disposal Group, Including Discontinued Operation, Straight-line Rent Deferred lease costs, less accumulated amortization of $268 and $207 as of March 31, 2013 and December 31, 2012, respectively Disposal Group, Including Discontinued Operation, Deferred Lease Costs, Net Disposal Group, Including Discontinued Operation, Deferred Lease Costs, Net Accumulated amortization on deferred lease costs Disposal Group, Including Discontinued Operation, Deferred Lease Costs, Accumulated Amortization Disposal Group, Including Discontinued Operation, Deferred Lease Costs, Accumulated Amortization Total other assets held for sale, net Disposal Group, Including Discontinued Operation, Other Assets Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] Assets: Assets [Abstract] Buildings and improvements, 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 Liabilities: Liabilities [Abstract] Intangible lease liabilities, accumulated amortization Intangible Lease Liabilities Accumulated Amortization Intangible Lease Liabilities Accumulated Amortization Stockholders' Equity: Stockholders' Equity Attributable to Parent [Abstract] Shares-in-trust, shares authorized Shares In Trust Authorized Shares In Trust Authorized Shares-in-trust, shares outstanding Shares In Trust, Outstanding Shares In Trust, Outstanding Preferred stock, par value (in dollars per share) Preferred Stock, No Par Value Preferred stock, shares authorized Preferred Stock, Shares Authorized Preferred stock, shares outstanding Preferred Stock, Shares Outstanding Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Accounting Policies [Abstract] Summary of Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Assets: Land Land Buildings and improvements, less accumulated depreciation of $902,978 and $883,008 as of March 31, 2013 and December 31, 2012, respectively Investment Building and Building Improvements, Net Investment Building and Building Improvements, Net Intangible lease assets, less accumulated amortization of $67,333 and $67,940 as of March 31, 2013 and December 31, 2012, 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, Net Net carrying amount as of the balance sheet date of investments in land, buildings, finite-lived intangibles, and construction in progress classified as 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 $375 and $346 as of March 31, 2013 and December 31, 2012, respectively Tenant And Notes Receivable Tenant Receivables, Including Straight Line Rental Revenue Receivables, and Notes Receivable. 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 $11,048 and $10,479 as of March 31, 2013 and December 31, 2012, respectively Deferred Finance Costs, Net Deferred lease costs, less accumulated amortization of $118,673 and $112,289 as of March 31, 2013 and December 31, 2012, respectively Deferred Costs, Leasing, Net Other assets held for sale, net Total assets Assets 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 $40,744 and $40,931 as of March 31, 2013 and December 31, 2012, respectively Off-market Lease, Unfavorable Interest rate swaps Total liabilities Liabilities Commitments and Contingencies Shares-in-trust, 150,000,000 shares authorized; none outstanding as of March 31, 2013 or December 31, 2012 Common Stock Held in Trust Preferred stock, no par value, 100,000,000 shares authorized; none outstanding as of March 31, 2013 or December 31, 2012 Preferred Stock, Value, Issued Common stock, $.01 par value, 750,000,000 shares authorized; 167,555,401 and 167,556,001 shares issued and outstanding as of March 31, 2013 and December 31, 2012, 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 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 Total stockholders’ equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and stockholders’ equity Liabilities and Equity 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 Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Fair Value Measurement of Financial Instruments [Abstract] Fair Value Measurement of Financial Instruments [Abstract] Fair Value, by Balance Sheet Grouping [Table] Fair Value, by Balance Sheet Grouping [Table] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value, Measurements, Fair Value Hierarchy [Domain] Level 1 [Member] Fair Value, Inputs, Level 1 [Member] Level 2 [Member] Fair Value, Inputs, Level 2 [Member] 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 Value [Member] Carrying (Reported) Amount, Fair Value Disclosure [Member] Estimated Fair Value [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 Restricted cash and escrows Restricted Cash and Escrows, Fair Value Disclosure This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of restricted cash and escrows existing as of the balance sheet date. Accounts payable and accrued expenses Accounts Payable, Fair Value Disclosure Interest rate swap liability Line of credit and notes payable Notes Payable, Fair Value Disclosure Fair Value Measurement of Financial Instruments Fair Value Disclosures [Text Block] Schedule of Notional Amounts of Outstanding Derivative Positions Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Schedule of Interest Rate Derivatives Schedule of Interest Rate Derivatives [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] Statement of Stockholders' Equity [Abstract] Dividends to common stockholders (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Weighted-average common shares – basic Weighted Average Number of Shares Outstanding, Basic Restricted stock awards (in shares) Incremental Common Shares Attributable to Share-based Payment Arrangements Weighted-average common shares – diluted Weighted Average Number of Shares Outstanding, Diluted Subsequent Events [Abstract] Other Subsequent Events Subsequent Events [Text Block] Line of Credit and Notes Payable Debt Disclosure [Text Block] Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Statement, Equity Components [Axis] 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] Other Comprehensive Loss [Member] Accumulated Other Comprehensive Income (Loss) [Member] Non-controlling Interest [Member] Noncontrolling Interest [Member] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance Balance (in shares) Shares repurchases as part of an announced program Stock Repurchased and Retired During Period, Value Shares repurchases as part of an announced program (in shares) Stock Repurchased and Retired During Period, Shares Offering costs associated with the issuance of common stock Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs Dividends to common stockholders ($0.80 (YTD 2012) and $0.20 (YTD 2013) 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 Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures Shares issued under the 2007 Omnibus Incentive Plan, net of tax (in shares) Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures Amortization of unvested shares granted under the 2007 Omnibus Incentive Plan Adjustments to Additional Paid in Capital, Share-based Compensation, Nonvested Shares, Requisite Service Period Recognition Net income attributable to noncontrolling interest Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to Piedmont Net Income (Loss) Attributable to Parent Other comprehensive income (loss) Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Balance Balance (in shares) Tenant receivables, net of allowance for doubtful accounts of $375 and $346 as of March 31, 2013 and December 31, 2012, respectively Accounts Receivable, Net Cumulative rental revenue recognized on a straight-line basis in excess of cash received in accordance with lease terms Deferred Rent Receivables, Net Tenant receivables, net Schedule of Letters of Credit Schedule of Letters of Credit [Table Text Block] Schedule of Letters of Credit [Table Text Block] Income Tax, Policy Income Tax, Policy [Policy Text Block] Income Statement [Abstract] 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 income (expense) Other Nonoperating Income (Expense) Net casualty loss Net Loss (Gain) from Casualty Event The net charge/(recovery) against earnings in the period related to a fire, explosion, or natural disaster (hurricane, earthquake). Equity in income of unconsolidated joint ventures Income (Loss) from Equity Method Investments 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/(loss) 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 Per share information – basic and diluted: Earnings Per Share, Basic and Diluted [Abstract] Income from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Basic and Diluted Share Income/(loss) from discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations, Net of Tax, Per Basic and Diluted Share Net income available to common stockholders (in dollars per share) Earnings Per Share, Basic and Diluted Weighted-average common shares outstanding – basic Weighted-average common shares outstanding – diluted Organization Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Schedule of Debt Schedule of Debt [Table Text Block] Schedule of Disposal Groups, Including Discontinued Operations, Results Of Operations Schedule of Disposal Groups, Including Discontinued Operations, Results Of Operations [Table Text Block] Schedule of Disposal Groups, Including Discontinued Operations, Results Of Operations [Table Text Block] Schedule of 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] Schedule of Debt Instruments [Table] Schedule of Debt Instruments [Table] Schedule of Debt Instruments [Table] Interest Rate by Type [Axis] Interest Rate by Type [Axis] Interest Rate by Type [Axis] Interest Rate, Type [Domain] Interest Rate, Type [Domain] Interest Rate, Type [Domain] LIBOR [Member] LIBOR [Member] LIBOR [Member] Derivative Instrument Risk [Axis] Derivative Contract Type [Domain] 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] Secured Debt [Member] Rate Debt Instrument, Interest Rate, Stated Percentage Weighted Average Rate Debt, Weighted Average Interest Rate Line of credit, effective interest rate Line of Credit Facility, Interest Rate at Period End Amount Outstanding Notes and Loans Payable Basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Number of properties in collateralized pool Number Of Properties In Collateralized Pool Number Of Properties In Collateralized Pool Effective interest rate Debt Instrument, Interest Rate, Effective Percentage LIBOR rate in effect LIBOR Interest Rate In Effect LIBOR Interest Rate In Effect Loss Contingencies [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event [Member] Subsequent Event [Member] Litigation Status [Axis] Litigation Status [Axis] Litigation Status [Domain] Litigation Status [Domain] Pending Litigation [Member] Pending Litigation [Member] Capital Expenditures by Type [Axis] Capital Expenditures By Type [Axis] Capital Expenditures By Type [Axis] Capital Expenditures by Type [Domain] Capital Expenditures By Type [Domain] [Domain] for Capital Expenditures By Type [Axis] Non-Incremental Capital Expenditures [Member] NonIncremental Capital Expenditures [Member] NonIncremental Capital Expenditures [Member] Incremental Capital Expenditures [Member] Incremental Capital Expenditures [Member] Incremental Capital Expenditures [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 1, July 2013 [Member] Letter of Credit 1, July 2013 [Member] Letter of Credit 1, July 2013 [Member] Letter of Credit 2, July 2013 [Member] Letter of Credit 2, July 2013 [Member] Letter of Credit 2, July 2013 [Member] Letter of Credit 3, July 2013 [Member] Letter of Credit 3, July 2013 [Member] Letter of Credit 3, July 2013 [Member] Loss Contingencies [Line Items] Potential obligations for tenant improvements Commitment to Provide Funding to Tenants for Capital Improvements Commitment to Provide Funding to Tenants for Capital Improvements Letters of credit outstanding Letters of Credit Outstanding, Amount Letter of credit, renewal period Letter of Credit Renewal Period Letter of Credit Renewal Period Litigation settlement expense Gain (Loss) Related to Litigation Settlement Period to appeal final court approval Loss Contingency, Plaintiffs, Period to Appeal Final Court Approval Loss Contingency, Plaintiffs, Period to Appeal Final Court Approval Fair Value, by Balance Sheet Grouping Fair Value, by Balance Sheet Grouping [Table Text Block] Acquisitions Business Combination Disclosure [Text Block] 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 [Axis] Variable Interest Entity, Classification [Domain] Variable Interest Entity, Classification [Domain] 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] TownPark 400, LLC [Member] TownPark 400, LLC [Member] TownPark 400, LLC [Member] Variable Interest Entity [Line Items] Variable Interest Entity [Line Items] Piedmont’s % Ownership of Entity Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage Net Carrying Amount Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net 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 Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Portland Portfolio [Member] Portland Portfolio [Member] Portland Portfolio [Member] 26200 Enterprise Way [Member] ENTERPRISE WAY 26200 [Member] ENTERPRISE WAY 26200 [Member] 110 & 112 Hidden Lake Circle Buildings [Member] Hidden Lake Circle Buildings [Member] Hidden Lake Circle Buildings [Member] 1111 Durham Avenue [Member] Durham Avenue 1111 [Member] Durham Avenue 1111 [Member] Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Gain/(Loss) on Sale Net Sales Proceeds Proceeds from Divestiture of Businesses, Net of Cash Divested Number of Real Estate Properties Sold Number of Real Estate Properties Sold Number of Real Estate Properties Sold Area of Land (in acres) Area of Land Sale price Disposal Group, Including Discontinued Operation, Sale Price Disposal Group, Including Discontinued Operation, Sale Price Rental income Disposal Group, Including Discontinued Operation, Rental Income Tenant reimbursements Disposal Group, Including Discontinued Operation, Tenant Reimbursement Disposal Group, Including Discontinued Operation, Tenant Reimbursement Property management fee revenue Disposal Group, Including Discontinued Operation, Property Management Fee Revenue Disposal Group, Including Discontinued Operation, Property Management Fee Revenue Other rental income Disposal Group, Including Discontinued Operation, Other Rental Income Disposal Group, Including Discontinued Operation, Other Rental Income 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 expenses 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 Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Noncontrolling Interest Other income (expense) Disposal Group Including Discontinued Other Income Expense Disposal Group Including Discontinued Other Income Expense Operating income, excluding gain/(loss) on sale Impairment loss Disclosure of Compensation Related Costs, Share-based Payments [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] Award Type [Axis] Award Type [Domain] Stock Awards [Member] Stock Awards [Member] Stock Awards [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Unvested Deferred Stock Awards, Beginning of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Deferred Stock Awards Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Adjustment to Estimated Future Grants of Performance Share Awards (in shares) Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Adjustment to Estimated Future Grants In Period Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Adjustment to Estimated Future Grants In Period Deferred Stock Awards Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Deferred Stock Awards Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Unvested Deferred Stock Awards, End of period (in shares) Unvested Deferred Stock Awards, Weighted-Average Grant Date Fair Value, Beginning of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Deferred Stock Awards Granted, Weighted-Average Grant Date Fair Value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Adjustment to Estimated Future Grants of Performance Share Awards, Weighted Average Grant Date Fair Value (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Adjustment to Estimated Future Grants In Period, Weighted Average Grant Date Fair Value Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Adjustment to Estimated Future Grants In Period, Weighted Average Grant Date Fair Value Deferred Stock Awards Vested, Weighted-Average Grant Date Fair Value (in 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 Deferred Stock Awards Forfeited, Weighted-Average Grant Date Fair Value (in 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 Deferred Stock Awards, Weighted-Average Grant Date Fair Value, End of period (in dollars per share) Award Type [Axis] Stock Awards, Granted May 11, 2010 [Member] Stock Awards, Granted May 11, 2010 [Member] Stock Awards, Granted May 11, 2010 [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] Stock Awards 2, Granted April 5, 2011 [Member] Stock Awards 2, Granted April 5, 2011 [Member] Stock Awards 2, Granted April 5, 2011 [Member] Stock Awards 1, Granted April 4, 2012 [Member] Stock Awards 1, Granted April 4 2012 [Member] Stock Awards 1, Granted April 4 2012 [Member] Stock Awards 2, Granted April 4, 2012 [Member] Stock Awards 2, Granted April 4 2012 [Member] Stock Awards 2, Granted April 4 2012 [Member] Net Shares Granted Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Net Shares Granted The number of share grants, net of shares surrended for taxes, made on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Grant Date Fair Value 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 in one year Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest Within One Year, Percent Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest Within One Year, Percent Of the shares granted, % expected to vest in two years Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest In Two Years, Percent Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest In Two Years, Percent Of the shares granted, % expected to vest in three years Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest In Three Years, Percent Share Based Compensation Arrangement By Share Based Payment Award, Equity Instruments Other Than Options, Expected to Vest In Three Years, Percent Unvested Shares Subsequent Event [Table] Subsequent Event [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Dividends declared (in dollars per share) Common Stock, Dividends, Per Share, Declared Percentage of leased properties Property management agreement, term Property Management Agreement, Term Property Management Agreement, Term Number of additional forward starting swaps Number of Interest Rate Derivatives Held Notional amount Statement of Other Comprehensive Income [Abstract] Legal Entity [Axis] Entity [Domain] Other comprehensive income/(loss): Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Effective portion of loss on derivative instruments that are designated and qualify as cash flow hedges (See Note 6) Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Less: Reclassification of previously recorded loss included in net income (See Note 6) Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax Other comprehensive income/(loss) Comprehensive income attributable to Piedmont Comprehensive Income (Loss), Net of Tax, Attributable to Parent Schedule of Nonvested Share Activity Schedule of Nonvested Share Activity [Table Text Block] Schedule of Outstanding Employee Deferred Stock Awards Schedule of Outstanding Employee Deferred Stock Awards [Table Text Block] Schedule of Outstanding Employee Deferred Stock Awards [Table Text Block] Schedule of Variable Interest Entities Schedule of Variable Interest Entities [Table Text Block] Award vesting period (in years) Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Period of predetermined peer group's total stockholder return Stock Awards, Performance Period Used In Calculation Stock Awards, Performance Period Used In Calculation Compensation expense related to stock awards Allocated Share-based Compensation Expense Unrecognized compensation cost related to nonvested Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized Unrecognized compensation cost related to nonvested, weighted-average vesting period (in years) Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition Tenant Receivables Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Variable Interest Entities Variable Interest Entities [Text Block] Describes how the entity aggregates Variable Interest Entities (VIE) for disclosure purposes, distinguishing between (a) VIEs that are not consolidated because the enterprise is not the primary beneficiary but has a variable interest and (b) VIEs that are consolidated Statement of Cash Flows [Abstract] Cash Flows from Operating Activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Operating distributions received from unconsolidated joint ventures Proceeds from 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] Depreciation Depreciation Amortization of deferred financing costs Amortization of Financing Costs and Discounts Other amortization Amortization of Intangible Assets Impairment loss on real estate assets Impairment of Real Estate Stock compensation expense Share-based Compensation Equity in income of unconsolidated joint ventures Income (Loss) from Equity Method Investments, Actual Cash Impact Income (Loss) from Equity Method Investments, Actual Cash Impact Gain on sale of real estate assets, net Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Non Cash Impact Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Non Cash Impact Changes in assets and liabilities: Increase (Decrease) in Operating Assets [Abstract] Increase in tenant receivables, net Increase (Decrease) in Accounts Receivable Decrease/(increase) in restricted cash and escrows Increase (Decrease) in Restricted Cash for Operating Activities 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 Increase 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 Net sales proceeds from wholly-owned properties 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)/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] 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 Costs of issuance of common stock Payments of Stock Issuance Costs Share repurchases as part of an announced program Payments for Repurchase of Common Stock Dividends paid and discount on dividend reinvestments Payments of Dividends Common Stock, Distributions To Noncontrolling Interest and Discount on Dividend Reinvestment Sum of a) The cash outflow from the distribution of an entity's earnings in the form of dividends to common stockholders, and b) Distributions to noncontrolling interest, and c)Discount on dividend reinvestments. Net cash provided by/(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) 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] 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. Stock Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Schedule of acquired properties Schedule of Business Acquisitions, by Acquisition [Table Text Block]