Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Jun. 30, 2016
Accounting Policies [Abstract]
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.
Principles of Consolidation	Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity ("VIE") of which Piedmont or any of its wholly-owned subsidiaries is considered to have the power to direct the activities of the entity and the obligation to absorb losses/right to receive benefits, or any entity in which Piedmont or any of its wholly-owned subsidiaries owns a controlling interest. In determining whether Piedmont or Piedmont OP has a controlling interest, the following factors, among others, are considered: equity ownership, voting rights, protective rights of investors, and participatory rights of investors. 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, 2015. All inter-company balances and transactions have been eliminated upon consolidation. Further, Piedmont has formed special purpose entities to acquire and hold real estate. Each special purpose entity is a separate legal entity. Consequently, the assets of these 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.
Use of Estimates	Use of Estimates The preparation of the accompanying consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying consolidated financial statements and notes. Actual results could differ from those estimates.
Income Taxes	Income Taxes Piedmont has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended, 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, POH, which have been provided for in the financial statements.
Accounting Pronouncements Adopted and Other Recent Accounting Pronouncements	Accounting Pronouncements Adopted during the Six Months Ended June 30, 2016 As of January 1, 2016, Piedmont early adopted the provisions of Financial Accounting Standards Board (the "FASB") Accounting Standards Update No. 2016-09, Compensation- Stock Compensation (Topic 718) Improvements to Employee Share-Based Payment Accounting ("ASU 2016-09"). The provisions in ASU 2016-09 simplify the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The implementation of ASU 2016-09 resulted in the reclassification of approximately $1.7 million related to income tax consequences for share-based compensation from cash outflows from operating activities to cash outflows from financing activities in the accompanying consolidated statements of cash flows for the six months ended June 30, 2015. Additionally, as of January 1, 2016, Piedmont also adopted Accounting Standards Update No. 2015-05, Intangibles- Goodwill and Other- Internal-Use Software (Subtopic 350-40) “Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement on a prospective basis. Other Recent Accounting Pronouncements The FASB has issued Accounting Standards Update No. 2016-05, Derivatives and Hedging (Topic 815), Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships ("ASU 2016-05"). The amendments in ASU 2016-05 clarify that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument does not, in and of itself, require de-designation of that hedging relationship provided that all other hedge accounting criteria continue to be met. The amendments in ASU 2016-05 are effective in the first quarter of 2017, and Piedmont does not anticipate any material impact to its consolidated financial statements as a result of adoption. The FASB has issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09") and Accounting Standards Update No. 2016-08, Revenue from Contracts with Customers (Topic 606) Principal versus Agent Considerations (Reporting Revenue Gross versus Net) ("ASU 2016-08"). The amendments in ASU 2014-09, which are further clarified in ASU 2016-08, as well as ASU 2016-10 and ASU 2016-12, change the criteria for the recognition of revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services using a five-step determination process. Steps 1 through 5 involve (i) identifying contracts with a customer, (ii) identifying the performance obligations in the contract, (iii) determining the transaction price, (iv) allocating the transaction price to the performance obligations, and (v) recognizing revenue as an entity satisfies a performance obligation. Additionally, lease contracts are specifically excluded from ASU 2014-09. The amendments in ASU 2014-09 and ASU 2016-08 are effective in the first quarter of 2018, and Piedmont is currently evaluating the potential impact, if any, of adoption. The FASB has issued Accounting Standards Update No. 2016-01, Financial Instruments - Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"). The amendments in ASU 2016-01 require equity investments, except those accounted for under the equity method of accounting, to be measured at estimated fair value with changes in fair value recognized in net income. Additionally, ASU 2016-01 simplifies the impairment assessment of equity investments, and eliminates certain disclosure requirements. The amendments in ASU 2016-01 are effective in the first quarter of 2018, and Piedmont is currently evaluating the potential impact of adoption. The FASB has issued Accounting Standards Update No. 2016-02, Leases (Topic 842), ("ASU 2016-02"). The amendments in ASU 2016-02 fundamentally change the definition of a lease, as well as the accounting for operating leases by requiring leasees to recognize assets and liabilities which arise from the lease, consisting of a liability to make lease payments (the lease liability) and a right-of-use asset, representing the right to use the leased asset over the term of the lease. Accounting for leases for lessors is substantially unchanged from prior practice, which means continuing to recognize lease revenue on a straight-line basis. The amendments in ASU 2016-02 are effective in the first quarter of 2019, and Piedmont is currently evaluating the potential impact of adoption. The FASB has issued Accounting Standards Update No. 2016-13, Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). The provisions of ASU 2016-13 replace the "incurred loss" approach with an "expected loss" model for impairing trade and other receivables, held-to-maturity debt securities, net investment in leases, and off-balance-sheet credit exposures, which will generally result in earlier recognition of allowance for losses. Additionally, the provisions change the classification of credit losses on available-for-sale securities as an allowance rather than reductions in the amortized cost of the securities. ASU 2016-13 is effective in the first quarter of 2020, with early adoption permitted as of January 1, 2019. Piedmont is currently evaluating the potential impact of adoption.

Disclosure of accounting policy for income taxes, which may include its accounting policies for recognizing and measuring deferred tax assets and liabilities and related valuation allowances, recognizing investment tax credits, operating loss carryforwards, tax credit carryforwards, and other carryforwards, methodologies for determining its effective income tax rate and the characterization of interest and penalties in the financial statements.