Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2013
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation The consolidated financial statements of Piedmont have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by U.S. generally accepted accounting principles (“GAAP”) for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year’s results and certain prior period amounts have been reclassified to conform to the current period financial statement presentation. The reclassifications relate to the required presentation of income from discontinued operations for properties sold and properties held for sale during the quarter ended March 31, 2013 and during the year ended December 31, 2012, respectively. Please refer to Note 10 for further details. None of these reclassifications affect net income attributable to Piedmont as presented in previous periods. Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity of which Piedmont or any of its wholly-owned subsidiaries is considered the primary beneficiary, or any entity in which Piedmont or any of its wholly-owned subsidiaries owns a controlling interest. For further information, refer to the financial statements and footnotes included in Piedmont’s Annual Report on Form 10-K for the year ended December 31, 2012. Further, Piedmont has formed special purpose entities to acquire and hold real estate. Each special purpose entity is a separate legal entity and consequently the assets of the special purpose entities are not available to all creditors of Piedmont. The assets owned by these special purpose entities are being reported on a consolidated basis with Piedmont’s assets for financial reporting purposes only. Income Taxes Piedmont has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), and has operated as such, beginning with its taxable year ended December 31, 1998. To qualify as a REIT, Piedmont must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its annual REIT taxable income. As a REIT, Piedmont is generally not subject to federal income taxes. Piedmont is subject to certain taxes related to the operations of properties in certain locations, as well as operations conducted by its taxable REIT subsidiary, which have been provided for in the financial statements.

Summary of Significant Accounting Policies

Basis of Presentation

The consolidated financial statements of Piedmont have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by U.S. generally accepted accounting principles (“GAAP”) for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year’s results and certain prior period amounts have been reclassified to conform to the current period financial statement presentation. The reclassifications relate to the required presentation of income from discontinued operations for properties sold and properties held for sale during the quarter ended March 31, 2013 and during the year ended December 31, 2012, respectively. Please refer to Note 10 for further details. None of these reclassifications affect net income attributable to Piedmont as presented in previous periods. Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity of which Piedmont or any of its wholly-owned subsidiaries is considered the primary beneficiary, or any entity in which Piedmont or any of its wholly-owned subsidiaries owns a controlling interest. For further information, refer to the financial statements and footnotes included in Piedmont’s Annual Report on Form 10-K for the year ended December 31, 2012.

Further, Piedmont has formed special purpose entities to acquire and hold real estate. Each special purpose entity is a separate legal entity and consequently the assets of the special purpose entities are not available to all creditors of Piedmont. The assets owned by these special purpose entities are being reported on a consolidated basis with Piedmont’s assets for financial reporting purposes only.

Income Taxes

Piedmont has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), and has operated as such, beginning with its taxable year ended December 31, 1998. To qualify as a REIT, Piedmont must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its annual REIT taxable income. As a REIT, Piedmont is generally not subject to federal income taxes. Piedmont is subject to certain taxes related to the operations of properties in certain locations, as well as operations conducted by its taxable REIT subsidiary, which have been provided for in the financial statements.