Summary of Significant Accounting Policies	3 Months Ended
Mar. 31, 2012
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, specifically relating to the required presentation of income from discontinued operations for the Eastpointe Corporate Center (sold in July 2011), the 5000 Corporate Court building (sold in August 2011), the 35 West Wacker Drive building (sold in December 2011), and the Portland Portfolio (sold in March 2012, see Note 9). 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, 2011. 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. Goodwill Goodwill is the excess of cost of an acquired entity over the amounts specifically assigned to assets acquired and liabilities assumed in purchase accounting for business combinations. Piedmont tests the carrying value of its goodwill for impairment on an annual basis, or on an interim basis if an event occurs or circumstances change that would indicate the carrying amount may be impaired. Such interim circumstances may include, but are not limited to, significant adverse changes in legal factors or in the general business climate, adverse action or assessment by a regulator, unanticipated competition, the loss of key personnel, or persistent declines in an entity’s stock price below carrying value of the entity. In September 2011, the Financial Accounting Standards Board ("FASB") issued an amendment regarding the testing of goodwill for impairment effective for Piedmont on January 1, 2012. Under the amended guidance, Piedmont has the option, should it chose to do so, to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, Piedmont concludes that the estimated fair value is greater than the carrying amount, then performing the two-step impairment test is unnecessary. However, if Piedmont chooses to forgo the availability of the qualitative analysis, the test prescribed by authoritative accounting guidance is a two-step test. The first step involves comparing the estimated fair value of the entity to its carrying value, including goodwill. Fair value is determined by adjusting the trading price of the stock for various factors including, but not limited to: (i) liquidity or transferability considerations, (ii) control premiums, and/or (iii) fully distributed premiums, if necessary, multiplied by the common shares outstanding. If such calculated fair value exceeds the carrying value, no further procedures or analysis is permitted or required. However, if the carrying value exceeds the calculated fair value, goodwill is potentially impaired and step two of the analysis would be required. Step two of the test involves calculating the implied fair value of goodwill by deducting the fair value of all tangible and intangible net assets of the entity from the entity’s fair value calculated in step one of the test. If the implied value of the goodwill (the remainder left after deducting the fair values of the entity from its calculated overall fair value in step one of the test) is less than the carrying value of goodwill, an impairment loss would be recognized.

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, specifically relating to the required presentation of income from discontinued operations for the Eastpointe Corporate Center (sold in July 2011), the 5000 Corporate Court building (sold in August 2011), the 35 West Wacker Drive building (sold in December 2011), and the Portland Portfolio (sold in March 2012, see Note 9). 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, 2011.

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.

Goodwill

Goodwill is the excess of cost of an acquired entity over the amounts specifically assigned to assets acquired and liabilities assumed in purchase accounting for business combinations. Piedmont tests the carrying value of its goodwill for impairment on an annual basis, or on an interim basis if an event occurs or circumstances change that would indicate the carrying amount may be impaired. Such interim circumstances may include, but are not limited to, significant adverse changes in legal factors or in the general business climate, adverse action or assessment by a regulator, unanticipated competition, the loss of key personnel, or persistent declines in an entity’s stock price below carrying value of the entity. In September 2011, the Financial Accounting Standards Board ("FASB") issued an amendment regarding the testing of goodwill for impairment effective for Piedmont on January 1, 2012. Under the amended guidance, Piedmont has the option, should it chose to do so, to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the fair value of the reporting unit is less than its carrying amount. If, after assessing the totality of events or circumstances, Piedmont concludes that the estimated fair value is greater than the carrying amount, then performing the two-step impairment test is unnecessary. However, if Piedmont chooses to forgo the availability of the qualitative analysis, the test prescribed by authoritative accounting guidance is a two-step test. The first step involves comparing the estimated fair value of the entity to its carrying value, including goodwill. Fair value is determined by adjusting the trading price of the stock for various factors including, but not limited to: (i) liquidity or transferability considerations, (ii) control premiums, and/or (iii) fully distributed premiums, if necessary, multiplied by the common shares outstanding. If such calculated fair value exceeds the carrying value, no further procedures or analysis is permitted or required. However, if the carrying value exceeds the calculated fair value, goodwill is potentially impaired and step two of the analysis would be required. Step two of the test involves calculating the implied fair value of goodwill by deducting the fair value of all tangible and intangible net assets of the entity from the entity’s fair value calculated in step one of the test. If the implied value of the goodwill (the remainder left after deducting the fair values of the entity from its calculated overall fair value in step one of the test) is less than the carrying value of goodwill, an impairment loss would be recognized.