Document and Entity Information - shares	3 Months Ended
Document and Entity Information - shares	Mar. 31, 2018	Apr. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Piedmont Office Realty Trust, Inc.
Entity Central Index Key	0001042776
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Amendment Flag	false
Entity Common Stock, Shares Outstanding		128,164,480

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets:
Land	$ 547,602	$ 544,794
Buildings and improvements, less accumulated depreciation of $811,760 and $785,206 as of March 31, 2018 and December 31, 2017, respectively	2,424,570	2,418,023
Intangible lease assets, less accumulated amortization of $83,063 and $99,145 as of March 31, 2018 and December 31, 2017, respectively	75,275	77,805
Construction in progress	15,226	11,710
Real estate assets held for sale, net	0	332,410
Total real estate assets	3,062,673	3,384,742
Amounts due from unconsolidated joint ventures	10	10
Cash and cash equivalents	6,729	7,382
Tenant receivables, net of allowance for doubtful accounts of $467 and $539 as of March 31, 2018 and December 31, 2017, respectively	12,040	12,139
Straight-line rent receivables	167,535	163,160
Note receivable	3,200	0
Restricted cash and escrows	1,464	1,373
Prepaid expenses and other assets	25,028	22,517
Goodwill	98,918	98,918
Interest rate swaps	725	688
Deferred lease costs, less accumulated amortization of $168,019 and $183,740 as of March 31, 2018 and December 31, 2017, respectively	257,368	261,907
Other assets held for sale, net	0	47,131
Total assets	3,635,690	3,999,967
Liabilities:
Unsecured debt, net of discount and unamortized debt issuance costs of $8,661 and $7,689 as of March 31, 2018 and December 31, 2017, respectively	1,498,339	1,535,311
Secured debt, net of premiums and unamortized debt issuance costs of $871 and $946 as of March 31, 2018 and December 31, 2017, respectively	191,305	191,616
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	83,786	216,653
Deferred income	29,751	29,582
Intangible lease liabilities, less accumulated amortization of $52,222 and $55,847 as of March 31, 2018 and December 31, 2017, respectively	42,699	38,458
Interest rate swaps	222	1,478
Other liabilities held for sale, net	0	380
Total liabilities	1,846,102	2,013,478
Commitments and Contingencies
Stockholders’ Equity:
Shares-in-trust, 150,000,000 shares authorized; none outstanding as of March 31, 2018 or December 31, 2017	0	0
Preferred stock, no par value, 100,000,000 shares authorized; none outstanding as of March 31, 2018 or December 31, 2017	0	0
Common stock, $.01 par value, 750,000,000 shares authorized; 130,024,873 and 142,358,940 shares issued and outstanding as of March 31, 2018 and December 31, 2017, respectively	1,300	1,424
Additional paid-in capital	3,680,241	3,677,360
Cumulative distributions in excess of earnings	(1,904,404)	(1,702,281)
Other comprehensive income	10,639	8,164
Piedmont stockholders’ equity	1,787,776	1,984,667
Noncontrolling interest	1,812	1,822
Total stockholders’ equity	1,789,588	1,986,489
Total liabilities and stockholders’ equity	$ 3,635,690	$ 3,999,967

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets:
Intangible lease assets, accumulated amortization	$ 83,063	$ 99,145
Tenant receivables, allowance for doubtful accounts	467	539
Deferred lease costs, accumulated amortization	168,019	183,740
Liabilities:
Discount, (premiums) and unamortized debt issuance costs	8,661	7,689
Intangible lease liabilities, accumulated amortization	$ 52,222	$ 55,847
Stockholders’ Equity:
Shares-in-trust, shares authorized (in shares)	150,000,000	150,000,000
Shares-in-trust, shares outstanding (in shares)	0	0
Preferred stock, par value (in dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	130,024,873	142,358,940
Common stock, shares outstanding (in shares)	130,024,873	142,358,940
Unsecured Debt
Liabilities:
Discount, (premiums) and unamortized debt issuance costs	$ 8,661	$ 7,689
Secured Debt
Liabilities:
Discount, (premiums) and unamortized debt issuance costs	(871)	(946)
Building and improvements
Assets:
Buildings and improvements, accumulated depreciation	$ 811,760	$ 785,206

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
Consolidated Statements of Income - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Revenues:
Rental income	$ 101,454	$ 118,039
Tenant reimbursements	22,994	24,837
Property management fee revenue	309	525
Other property related income	5,143	5,062
Total revenues	129,900	148,463
Expenses:
Property operating costs	51,859	55,830
Depreciation	27,145	30,768
Amortization	16,733	20,415
General and administrative	6,552	8,150
Operating expenses	102,289	115,163
Real estate operating income	27,611	33,300
Other income (expense):
Interest expense	(13,758)	(18,057)
Other income/(expense)	446	(100)
Equity in income of unconsolidated joint ventures	0	11
Loss on extinguishment of debt	(1,680)	0
Gain/(loss) on sale of real estate assets, net	45,209	(53)
Net income	57,828	15,101
Plus: Net loss applicable to noncontrolling interest	2	3
Net income applicable to Piedmont	$ 57,830	$ 15,104
Per share information – basic:
Net income applicable to common stockholders (in usd per share)	$ 0.43	$ 0.10
Per share information – diluted:
Net income applicable to common stockholders (in usd per share)	$ 0.42	$ 0.10
Weighted-average common shares outstanding – basic (in shares)	135,876,652	145,286,930
Weighted-average common shares outstanding – diluted (in shares)	136,182,728	145,833,488

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income applicable to Piedmont	$ 57,830	$ 15,104
Other comprehensive income:
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	1,517	1,044
Plus: Reclassification of net loss included in net income (See Note 6)	1,052	1,306
Gain on investment in available for sale securities	0	12
Other comprehensive income	2,569	2,362
Comprehensive income applicable to Piedmont	$ 60,399	$ 17,466

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Cumulative Distributions in Excess of Earnings	Other Comprehensive Income/(Loss)	Non- controlling Interest
Balance at Dec. 31, 2016	$ 2,097,703	$ 1,452	$ 3,673,128	$ (1,580,863)	$ 2,104	$ 1,882
Balance (in shares) at Dec. 31, 2016		145,235,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss applicable to noncontrolling interest	(3)
Net income applicable to Piedmont	15,104
Other comprehensive income	$ 2,362
Balance (in shares) at Mar. 31, 2017	145,320,000
Balance at Dec. 31, 2016	$ 2,097,703	$ 1,452	3,673,128	(1,580,863)	2,104	1,882
Balance (in shares) at Dec. 31, 2016		145,235,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	(61,750)	$ (31)		(61,719)
Share repurchases as part of an announced plan (in shares)		(3,133,000)
Offering costs	(182)		(182)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(193,541)		(233)	(193,263)		(45)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	4,650	$ 3	4,647
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		257,000
Net loss applicable to noncontrolling interest	(15)					(15)
Net income applicable to Piedmont	133,564			133,564
Other comprehensive income	6,060				6,060
Balance at Dec. 31, 2017	$ 1,986,489	$ 1,424	3,677,360	(1,702,281)	8,164	1,822
Balance (in shares) at Dec. 31, 2017	142,358,940	142,359,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of accounting change (adoption of ASU 2016-01)	$ 0			94	(94)
Share repurchases as part of an announced plan	(231,888)	$ (125)		(231,763)
Share repurchases as part of an announced plan (in shares)		(12,482,000)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(28,311)		(19)	(28,284)		(8)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	2,901	$ 1	2,900
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		148,000
Net loss applicable to noncontrolling interest	(2)					(2)
Net income applicable to Piedmont	57,830			57,830
Other comprehensive income	2,569				2,569
Balance at Mar. 31, 2018	$ 1,789,588	$ 1,300	$ 3,680,241	$ (1,904,404)	$ 10,639	$ 1,812
Balance (in shares) at Mar. 31, 2018	130,024,873	130,025,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash Flows from Operating Activities:
Net income	$ 57,828	$ 15,101
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	27,145	30,768
Amortization of debt issuance costs and settled interest rate swaps, net	(201)	409
Other amortization	15,984	20,129
Loss on extinguishment of debt	1,665	0
Stock compensation expense	1,025	2,897
Equity in income of unconsolidated joint ventures	0	(11)
(Gain)/loss on sale of real estate assets, net	(45,209)	53
Changes in assets and liabilities:
Increase in tenant and straight-line rent receivables, net	(5,048)	(6,043)
Decrease in prepaid expenses and other assets	1,975	1,746
Cash received upon settlement of interest rate swaps	807
Decrease in accounts payable and accrued expenses	(22,716)	(17,008)
Increase in deferred income	55	2,253
Net cash provided by operating activities	33,310	50,294
Cash Flows from Investing Activities:
Acquisition of real estate assets, related intangibles, and cash held in escrow for acquisitions	(28,147)	0
Capitalized expenditures, net of accruals	(12,760)	(28,203)
Investment in unconsolidated joint venture	0	(284)
Net sales proceeds from wholly-owned properties	415,078	(64)
Note receivable issuance	(3,200)	0
Deferred lease costs paid	(2,596)	(4,270)
Net cash provided by/(used in) investing activities	368,375	(32,821)
Cash Flows from Financing Activities:
Debt issuance costs paid	(101)	(63)
Proceeds from debt	716,225	100,000
Repayments of debt	(754,359)	(55,345)
Value of shares withheld to pay tax obligations related to employee stock compensation	(737)	(1,128)
Repurchases of common stock as part of announced plan	(233,164)	0
Dividends paid and discount on dividend reinvestments	(130,111)	(61,080)
Net cash used in financing activities	(402,247)	(17,616)
Net decrease in cash, cash equivalents, and restricted cash and escrows	(562)	(143)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	8,755	8,204
Cash, cash equivalents, and restricted cash and escrows, end of period	$ 8,193	$ 8,061

Organization	3 Months Ended
Organization	Mar. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Piedmont Office Realty Trust, Inc. (“Piedmont”) (NYSE: PDM) is a Maryland corporation that operates in a manner so as to qualify as a real estate investment trust (“REIT”) for federal income tax purposes and engages in the acquisition, development, management, and ownership of commercial real estate properties located primarily in the Eastern-half of the United States, including properties that are under construction, are newly constructed, or have operating histories. Piedmont was incorporated in 1997 and commenced operations in 1998. Piedmont conducts business primarily through Piedmont Operating Partnership, L.P. (“Piedmont OP”), a Delaware limited partnership, as well as performing the management of its buildings through two wholly-owned subsidiaries, Piedmont Government Services, LLC and Piedmont Office Management, LLC. Piedmont owns 99.9% of, and is the sole general partner of, Piedmont OP and as such, possesses full legal control and authority over the operations of Piedmont OP. The remaining 0.1% ownership interest of Piedmont OP is held indirectly by Piedmont through its wholly-owned subsidiary, Piedmont Office Holdings, Inc. ("POH"), the sole limited partner of Piedmont OP. Piedmont OP owns properties directly, through wholly-owned subsidiaries, and through various joint ventures which we control. References to Piedmont herein shall include Piedmont and all of its subsidiaries, including Piedmont OP and its subsidiaries and joint ventures. As of March 31, 2018, Piedmont owned 53 in-service office properties and one redevelopment asset. Piedmont's 53 in-service office properties comprise approximately 16 million square feet of primarily Class A commercial office space, and were approximately 91.3% leased. As of March 31, 2018, approximately 90% of Piedmont's Annualized Lease Revenue (unaudited) was generated from select sub-markets located primarily within eight major office markets located in the Eastern-half of the United States: Atlanta, Boston, Chicago, Dallas, Minneapolis, New York, Orlando, and Washington, D.C. Piedmont internally evaluates all of its real estate assets as one operating segment, and accordingly does not report segment information.

Summary of Significant Accounting Policies

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

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 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.

Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity ("VIE") for 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, 2017.

All intercompany 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

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

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, subject to fulfilling, among other things, its taxable income distribution requirement. 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.

Tax Cuts and Jobs Act

The Tax Cuts and Jobs Act ("H.R. 1"), which generally took effect for taxable years that began on or after January 1, 2018 (subject to certain exceptions), makes many significant changes to the U.S. federal income tax laws that will profoundly impact the taxation of individuals and corporations (including both regular C corporations and corporations that have elected to be taxed as REITs). For example, H.R. 1 limits the ability of corporations to utilize net operating loss carryforwards and limits the deductibility of business interest for all taxpayers, subject to an exception for taxpayers that are engaged in certain specified real property trades or business who make an irrevocable election not to apply the limitation to a particular real property trade or business and to depreciate their real property investments held in such trade or business using the less favorable alternative depreciation system. To date, the IRS has issued only limited guidance with respect to certain of the provisions of H.R. 1, and there are numerous interpretive issues that will require guidance. In addition, changes made by H.R. 1 may require Piedmont to accrue certain income for U.S. federal income tax purposes no later than when such income is taken into account as revenue on its GAAP-based financial statements, unless the income is already subject to certain special methods of accounting under the Code. This could cause Piedmont to recognize taxable income prior to the receipt of the associated cash and accordingly, increase its distribution levels in order to maintain its status as a REIT. H.R. 1 also includes limitations on the deductibility of certain compensation paid to Piedmont's executives, certain interest payments, and certain net operating loss carryforwards, each of which could potentially increase Piedmont's taxable income and its required distributions. Piedmont recorded an approximate $0.2 million reduction to its tax liability related to its taxable REIT subsidiary as a result of the rate reduction included in H.R. 1 during the three months ended March 31, 2018. Although management is still evaluating the other effects of H.R. 1, Piedmont does not believe that H.R. 1 will significantly impact its financial statements.

Reclassifications

Certain prior period amounts presented in the accompanying consolidated statements of income have been reclassified to conform to the current period financial statement presentation. During the three months ended March 31, 2018, these amounts included: (i) the reclassification of approximately $5.1 million of parking, antennae license and fiber income that was previously included in rental income into other property related income, as well as certain other miscellaneous revenue into tenant reimbursements and/or property management fee revenue for the three months ended March 31, 2017 in conjunction with the adoption of the Revenue Recognition Amendments, as further defined and described below; and (ii) the reclassification of $0.4 million of expense related to certain regional employees who are primarily engaged in the operation and management of properties that was previously included in general and administrative expense for the three months ended March 31, 2017 to property operating costs.

Accounting Pronouncements Adopted during the Quarter Ended March 31, 2018

Revenue Recognition

On January 1, 2018, Piedmont adopted 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") issued by the Financial Accounting Standards Board (the "FASB"). The amendments in ASU 2014-09, which are further clarified in ASU 2016-08, as well as Accounting Standards Update 2016-10, Accounting Standards Update 2016-12, and Accounting Standards Update 2016-20 (collectively the "Revenue Recognition Amendments") change the criteria for the recognition of certain revenue streams 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.

Piedmont's revenues which are included in the scope of the Revenue Recognition Amendments include its property management fee revenue, the majority of its parking revenue, as well as certain license agreements which allow third-parties to place their antennas or fiber-optic cabling on or inside Piedmont's buildings. Lease contracts are specifically excluded from the Revenue Recognition Amendments and, Piedmont intends to utilize a leasing practical expedient, which has been tentatively approved by the FASB, to group certain non-lease components related to operating expense reimbursements with other leasing components, provided they meet certain criteria. Because the timing and pattern of transfer of Piedmont's non-lease related revenue already followed the prescribed method of the Revenue Recognition Amendments, Piedmont was able to effectively adopt these amendments on a full retrospective basis, with no impact to the timing of recognition of the related revenue; however, such non-lease revenues are now being presented as "Other property related income" in the accompanying consolidated statements of income. Further, for comparative purposes, during the three months ended March 31, 2018, Piedmont reclassified approximately $5.1 million of parking, antennae license, and fiber income that was previously included in rental income into other property related income, as well as certain other miscellaneous revenue into tenant reimbursements and/or property management fee revenue during the three months ended March 31, 2017. Piedmont did not elect to adopt any practical expedients provided by the Revenue Recognition Amendments.

A detail of Piedmont's total revenues as of March 31, 2018 and 2017 (after reclassifications as a result of the adoption of the Revenue Recognition Amendments), including a detailed description of each line item is as follows:



			(After Adoption of Revenue Recognition Amendments)
	Three Months Ended March 31, 2018		Three Months Ended March 31, 2017
Rental income	$	101,454	$	118,039
Tenant reimbursements	22,994		24,837
Property management fee revenue	309		525
Other property related income	5,143		5,062
Total revenues	$	129,900	$	148,463

Rental income - consists of revenue from leases with Piedmont's tenants, which is not within the scope of the Revenue Recognition Amendments.

Tenant reimbursements - consists of revenue derived from reimbursements for services prescribed by leases with Piedmont's tenants separate from, but in conjunction with, the revenue generated from leasing office space. Such income is not within the scope of the Revenue Recognition Amendments.

Property management fee revenue - consists of revenue earned by Piedmont related to operating and managing office properties owned by other third-parties. Such income is within the scope of the Revenue Recognition Amendments; however, because the property management services represent a performance obligation that would be satisfied over the length of the contract, not at any specific point in time, and has the same measure of transfer (time elapsed), property management fee revenue will be recognized over time, consistent with the timing of Piedmont’s historic recognition. Any variable consideration transferred as part of these management agreements will continue to be recognized in the quarter that the underlying cash receipts are collected, consistent with the allocation objective of allocating the transaction price in an amount that depicts the amount of consideration to which Piedmont expects to be entitled in exchange for transferring the promised service to the customer.

Other property related income - consists of all other property related income from Piedmont's customers (tenants) that is not derived from a contract meeting the definition of a lease. Examples of such income are parking revenue and income from licenses with unrelated third-parties to place antennae and/or fiber optic cables in or on Piedmont's buildings. Since these services are substantially the same and have the same pattern of transfer, there is no timing difference between the recognition of other property related income and the recognition of the underlying expense/delivery of “service” under the new Revenue Recognition Amendments. Additionally, no modification to the timing of Piedmont’s previous revenue recognition is necessary, as these items have been recognized historically in accordance with this pattern of transfer.

Gain/(loss) on Sale of Real Estate Assets

On January 1, 2018, Piedmont adopted Accounting Standards Update No. 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20): Clarifying the Scope of Asset Derecognition Guidance and Accounting for Partial Sales of Nonfinancial Assets ("ASU 2017-05") concurrent with the Revenue Recognition Amendments mentioned above. Piedmont elected to apply the amendments of ASU 2017-05 on a full retrospective basis; however, there were no adjustments to previously recorded gains/(losses) on real estate as a result of the transition.

Equity Investments Held in Non-qualified Deferred Compensation Plan

On January 1, 2018, Piedmont adopted Accounting Standards Update No. 2016-01, Financial Instruments - Overall (Subtopic 825-10), Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01"), as well as Accounting Standards Update No. 2018-03 Technical Corrections and Improvements to Financial Instruments-Overall (Subtopic 825-10) ("ASU 2018-03"). These amendments 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. Investments in trading securities held in a "rabbi trust" by Piedmont are the only securities affected by ASU 2016-01 and ASU 2018-03. As such, Piedmont has made a cumulative-effect adjustment to its consolidated balance sheet and consolidated statements of stockholders' equity of approximately $0.1 million from other comprehensive income to cumulative distributions in excess of earnings, and has recorded changes in fair value in net income for the three months ended March 31, 2018 related to these investment securities.

Interest Rate Derivatives

On January 1, 2018, Piedmont early adopted Accounting Standards Update No. 2017-12, Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities ("ASU 2017-12"). Piedmont adopted ASU 2017-12 using the modified retrospective transition method; however, no adjustment was necessary to account for the cumulative effect of the change on the opening balance of each affected component of equity in the consolidated balance sheet as of the date of adoption because there was no cumulative ineffectiveness that had been recorded on Piedmont's existing interest rate swaps as of December 31, 2017, and all other trades were perfectly effective. The amended presentation and disclosure guidance which is required to be presented prospectively is provided in Note 6.

Other Recent Accounting Pronouncements

The FASB has issued Accounting Standards Update No. 2016-02, Leases (Topic 842) ("ASU 2016-02"), which fundamentally changes the definition of a lease, as well as the accounting for operating leases by requiring lessees 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 by lessors is substantially unchanged from prior practice as lessors will continue to recognize lease revenue on a straight-line basis. Additionally, a practical expedient tentatively approved by the FASB will allow certain non-lease operating expense reimbursements to be accounted for as part of the lease provided certain criteria are met. Further, the FASB has issued Accounting Standards Update No. 2018-01 Leases (Topic 842) Land Easement Practical Expedient for Transition to Topic 842 ("ASU 2018-01"). The amendments to ASU No. 2018-01 clarify that a land easement is required to be evaluated to determine whether it should be accounted for as a lease upon adoption of ASU 2016-02, and provides an optional practical transition expedient allowing entities not currently assessing land easements under existing leasing guidance prior to adoption of ASU 2016-02 to not apply the new guidance to land easements existing at the date of initial adoption of ASU 2016-02. The amendments in ASU 2016-02 and ASU 2018-01 are effective in the first quarter of 2019. Although management continues to evaluate the guidance and disclosures required by ASU 2016-02, Piedmont does not anticipate any material impact to its consolidated financial statements as a result of adoption related to lessor accounting. However, Piedmont does expect to record a right-to-use asset and related liability under lessee accounting, and Piedmont is still evaluating the potential impact of such lessee accounting.

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 allowances for credit losses. Additionally, the provisions change the classification of credit losses related to available-for-sale securities to an allowance, rather than a direct reduction of 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.

Acquisitions

3 Months Ended

Mar. 31, 2018

Business Combinations [Abstract]

Acquisitions

During the three months ended March 31, 2018, Piedmont acquired one property using proceeds available as a result of dispositions (see Note 9) in January 2018 and cash on hand, as noted below:



Property	Metropolitan Statistical Area	Date of Acquisition	Ownership Percentage Acquired		Rentable Square Feet	Percentage Leased as of Acquisition		Net Contractual Purchase Price (in millions)
501 West Church Street	Orlando, Florida	February 23, 2018	100	%	182,461	100	%	$	28.0

Debt

3 Months Ended

Mar. 31, 2018

Debt Disclosure [Abstract]

Debt

During the three months ended March 31, 2018, Piedmont fully repaid the balances of the $300 Million Unsecured 2013 Term Loan and the $170 Million Unsecured 2015 Term Loan using proceeds from the 2017 Disposition Portfolio (see Note 9) and cash on hand, as well as drawing on its $500 Million Unsecured 2015 Line of Credit. Further, Piedmont had net borrowings during the three months ended March 31, 2018 on its $500 Million Unsecured 2015 Line of Credit of approximately $184.0 million.

Additionally during the three months ended March 31, 2018, Piedmont entered into a $250 million unsecured term loan facility (the “$250 Million Unsecured 2018 Term Loan”) with a consortium of lenders. The term of the $250 Million Unsecured 2018 Term Loan is seven years with a maturity date of March 31, 2025; however, Piedmont may prepay the $250 Million Unsecured 2018 Term Loan, in whole or in part, at any time after March 29, 2020 without premium or penalty. The proceeds of the $250 Million Unsecured 2018 Term Loan were used to pay down the balance outstanding under the $500 Million Unsecured 2015 Line of Credit.

The $250 Million Unsecured 2018 Term Loan has the option to bear interest at varying levels based on either (i) the London Interbank Offered Rate (“LIBOR”) for an interest period selected by Piedmont of one, two, three, or six months, or to the extent available from all lenders in each case, one year or periods of less than one month, or (ii) Base Rate, defined as the greater of the prime rate, the federal funds rate plus 0.5%, or LIBOR for a one-month period plus 1%; plus a stated interest rate spread based on the higher credit rating level issued for either Piedmont or Piedmont OP. The stated interest rate spread over LIBOR can vary from 1.45% to 2.40% based upon the then current credit rating of Piedmont or Piedmont OP, whichever is higher. As of the closing of the $250 Million Unsecured 2018 Term Loan, the current stated interest rate spread on the loan was 1.60%.

Under the $250 Million Unsecured 2018 Term Loan, Piedmont is subject to certain financial covenants that require, among other things, the maintenance of an unencumbered interest coverage ratio of at least 1.75, an unencumbered leverage ratio of at least 1.60, a fixed charge coverage ratio of at least 1.50, a leverage ratio of no more than 0.60, and a secured debt ratio of no more than 0.40. In addition, Piedmont entered into three interest rate swap agreements for a total notional amount of $150 million which effectively fixed $150 million of the $250 Million Unsecured 2018 Term Loan at an interest rate of approximately 4.11% (see Note 6 for further information).

The following table summarizes the terms of Piedmont’s indebtedness outstanding as of March 31, 2018 and December 31, 2017 (in thousands):



Facility ⁽¹⁾	Stated Rate		Effective Rate ⁽²⁾			Maturity		Amount Outstanding as of
Facility ⁽¹⁾	Stated Rate		Effective Rate ⁽²⁾			Maturity		March 31, 2018		December 31, 2017
Secured (Fixed)
$35 Million Fixed-Rate Loan ⁽³⁾	5.55	%	3.75	%		9/1/2021		$	30,434	$	30,670
$160 Million Fixed-Rate Loan ⁽⁴⁾	3.48	%	3.58	%		7/5/2022		160,000		160,000
Net premium and unamortized debt issuance costs								871		946
Subtotal/Weighted Average ⁽⁵⁾	3.81	%						191,305		191,616
Unsecured (Variable and Fixed)
$170 Million Unsecured 2015 Term Loan	LIBOR + 1.125%		2.54	%		5/15/2018		—		170,000
$300 Million Unsecured 2013 Term Loan	LIBOR + 1.20%		2.78	%	⁽⁸⁾	1/31/2019		—		300,000
$500 Million Unsecured 2015 Line of Credit	LIBOR + 1.00%		2.87	%	⁽⁶⁾	6/18/2019	⁽⁹⁾	207,000		23,000
$300 Million Unsecured 2011 Term Loan	LIBOR + 1.15%		3.35	%	⁽⁸⁾	1/15/2020		300,000		300,000
$350 Million Senior Notes	3.40	%	3.43	%		6/01/2023		350,000		350,000
$400 Million Senior Notes	4.45	%	4.10	%		3/15/2024		400,000		400,000
$250 Million Unsecured 2018 Term Loan ⁽⁶⁾	LIBOR + 1.60%		3.86	%	⁽¹⁰⁾	3/31/2025		250,000		—
Discounts and unamortized debt issuance costs ⁽⁷⁾								(8,661)		(7,689)
Subtotal/Weighted Average ⁽⁵⁾	3.67	%						1,498,339		1,535,311
Total/Weighted Average ⁽⁵⁾	3.69	%						$	1,689,644	$	1,726,927


⁽¹⁾	Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of March 31, 2018 and December 31, 2017 is interest-only.


⁽²⁾	Effective rate after consideration of settled or in-place interest rate swap agreements, issuance premiums/discounts, and/or fair market value adjustments upon assumption of debt.


⁽³⁾	Collateralized by the 5 Wall Street building in Burlington, Massachusetts.


⁽⁴⁾	Collateralized by the 1901 Market Street building in Philadelphia, Pennsylvania.


⁽⁵⁾	Weighted average is based on contractual balance of outstanding debt and the stated or effectively fixed interest rates as of March 31, 2018.


⁽⁶⁾	On a periodic basis, Piedmont may select from multiple interest rate options, including the prime rate and various-length LIBOR locks on all or a portion of the principal. All LIBOR selections are subject to an additional spread over the selected rate based on Piedmont’s current credit rating.


⁽⁷⁾	As a result of repaying the $170 Million Unsecured 2015 Term Loan and the $300 Million Unsecured 2013 Term Loan in January 2018, Piedmont recorded a loss on extinguishment of debt of approximately $0.4 million related to the write-off of associated discounts and unamortized debt issuance costs.


⁽⁸⁾	The facility has a stated variable rate; however, Piedmont has entered into interest rate swap agreements which effectively fix, exclusive of Piedmont's credit rating, the rate shown as the effective rate.


⁽⁹⁾	Piedmont may extend the term for up to one additional year (through two available six month extensions to a final extended maturity date of June 18, 2020) provided Piedmont is not then in default and upon payment of extension fees.

⁽¹⁰⁾

The facility has a stated variable rate; however, Piedmont entered into $100 million in notional amount of seven-year interest rate swap agreements and $50 million in notional amount of two-year interest rate swap agreements, resulting in an effectively fixed interest rate on $150 million of the term loan at 4.11% through March 29, 2020 and 4.21% from March 30, 2020 through the loan's maturity date of March 31, 2025, assuming no change in Piedmont's credit rating. For the portion of the $250 Million Unsecured 2018 Term Loan that continues to have a variable interest rate, Piedmont may select from multiple interest rate options, including the prime rate and various length LIBOR locks. All LIBOR selections are subject to an additional spread (1.60% as of March 31, 2018) over the selected interest rate based on Piedmont's then current credit rating. The rate presented is the weighted-average rate for the effectively fixed and variable portions of the debt outstanding.

Piedmont made interest payments on all debt facilities, including interest rate swap cash settlements, of approximately $15.9 million and $19.2 million for the three months ended March 31, 2018 and 2017, respectively. Also, Piedmont capitalized interest of approximately $0.1 million for both the three months ended March 31, 2018 and 2017. As of March 31, 2018, Piedmont believes it was in compliance with all financial covenants associated with its debt instruments. See Note 7 for a description of Piedmont’s estimated fair value of debt as of March 31, 2018.

Variable Interest Entities

3 Months Ended

Mar. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Variable Interest Entities

Variable interest holders who have the power to direct the activities of the VIE that most significantly impact the entity’s economic performance and have the obligation to absorb the majority of losses of the entity or the right to receive significant benefits of the entity must consolidate the VIE. Each of the following VIEs has the sole purpose of holding land and office buildings and their resulting operations, and are classified in the accompanying consolidated balance sheets in the same manner as Piedmont’s wholly-owned properties.

A summary of Piedmont’s interests in its consolidated VIEs and their related carrying values as of March 31, 2018 and December 31, 2017 is as follows (net carrying amount in millions):



Entity	Piedmont’s % Ownership of Entity	Related Building	Net Carrying Amount as of March 31, 2018		Net Carrying Amount as of December 31, 2017		Primary Beneficiary Considerations
1201 Eye Street N.W. Associates, LLC	98.6%	1201 Eye Street	$	83.7	$	81.1	In accordance with the partnership’s governing documents, Piedmont currently receives 100% of the cash flow of the entity and has sole discretion in directing the management and leasing activities of the building.
1225 Eye Street N.W. Associates, LLC	98.1%	1225 Eye Street	$	64.3	$	65.2	In accordance with the partnership’s governing documents, Piedmont currently receives 100% of the cash flow of the entity and has sole discretion in directing the management and leasing activities of the building.
Piedmont 500 W. Monroe Fee, LLC	100%	500 W. Monroe	$	260.8	$	263.2	The Omnibus Agreement with the previous owner includes equity participation rights upon sale of the property for the previous owner, if certain financial returns are achieved; however, Piedmont has sole decision making authority and is entitled to 100% of the economic benefits of the property until such returns are met.

Derivative Instruments

3 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Instruments

Risk Management Objective of Using Derivatives

In addition to operational risks which arise in the normal course of business, Piedmont is exposed to economic risks such as interest rate, liquidity, and credit risk. In certain situations, Piedmont has entered into derivative financial instruments such as interest rate swap agreements and other similar agreements to manage interest rate risk exposure arising from current or future variable rate debt transactions. Interest rate swap agreements involve the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. Piedmont’s objective in using interest rate derivatives is to add stability to interest expense and to manage its exposure to interest rate movements.

Cash Flow Hedges of Interest Rate Risk

Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for Piedmont making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. In January 2018, Piedmont repaid the $300 Million Unsecured 2013 Term Loan in advance of its maturity without penalty (see Note 4 above). In connection with this early debt prepayment, six interest rate swap agreements which were identified as cash flow hedges were also terminated, resulting in a receipt of approximately $0.8 million from Piedmont's counterparties for the settlement of the swaps. These proceeds were recorded in accumulated other comprehensive income/(loss) ("OCI") and will be amortized as an offset to interest expense in the consolidated statement of income over the original term of the terminated interest rate swaps through January 2019. In connection with this termination Piedmont also recognized a non-cash loss of approximately $1.3 million due to it becoming probable that the hedged forecasted transactions would not occur, offset by a mark-to-market gain on these cash flow hedges of approximately $0.1 million for the three months ended March 31, 2018.

As of March 31, 2018, Piedmont was party to other interest rate swap agreements, all of which are designated as effective cash flow hedges and fully hedge the variable cash flows covering the entire outstanding balance of the $300 Million Unsecured 2011 Term Loan, and $150 million of the $250 Million Unsecured 2018 Term Loan. The maximum length of time over which Piedmont is hedging its exposure to the variability in future cash flows for forecasted transactions is 84 months.

A detail of Piedmont’s interest rate derivatives outstanding as of March 31, 2018 is as follows:

Interest Rate Derivatives:

Number of Swap Agreements

Associated Debt Instrument

Total Notional Amount

(in millions)

Effective Date

Maturity Date

Interest rate swaps

$300 Million Unsecured 2011 Term Loan

300

11/22/2016

1/15/2020

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

100

3/29/2018

3/31/2025

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

3/29/2018

3/29/2020

Total

450

Piedmont presents its interest rate derivatives on its consolidated balance sheets on a gross basis as interest rate swap assets and interest rate swap liabilities. A detail of Piedmont’s interest rate derivatives on a gross and net basis as of March 31, 2018 and December 31, 2017, respectively, is as follows (in thousands):



Interest rate swaps classified as:	March 31, 2018			December 31, 2017
Gross derivative assets	$	725		$	688
Gross derivative liabilities	(222		)	(1,478		)
Net derivative asset/(liability)	$	503		$	(790	)

The gain/(loss) on Piedmont's interest rate derivatives, including previously settled forward swaps, that was recorded in OCI and the accompanying consolidated statements of income as a component of interest expense for the three months ended March 31, 2018 and 2017, respectively, was as follows (in thousands):



	Three Months Ended
Interest Rate Swaps in Cash Flow Hedging Relationships	March 31, 2018		March 31, 2017
Amount of gain recognized in OCI	$	1,517	$	1,044
Amount of previously recorded gain/(loss) reclassified from OCI into Interest Expense	$	206	$	(1,306	)
Amount of loss recognized in Other Income/(Expense) on derivatives from OCI into Loss on Extinguishment of Debt	$	1,258	$	—

Total amount of Interest Expense presented in the consolidated statements of income	$	13,758	$	18,057
Total amount of Loss on Extinguishment of Debt presented in the consolidated statements of income	$	1,680	$	—

Piedmont estimates that approximately $1.8 million will be reclassified from OCI as a reduction of interest expense over the next twelve months. Piedmont recognized no hedge ineffectiveness on its cash flow hedges during the three months ended March 31, 2018 and 2017, respectively.

Additionally, see Note 7 for fair value disclosures of Piedmont's derivative instruments.

Credit-risk-related Contingent Features

Piedmont has agreements with its derivative counterparties that contain a provision whereby if Piedmont defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then Piedmont could also be declared in default on its derivative obligations. If Piedmont were to breach any of the contractual provisions of the derivative contracts, it could be required to settle its liability obligations under the agreements at their termination value of the estimated fair values plus accrued interest, or approximately $0.1 million as of March 31, 2018. Additionally, Piedmont has rights of set-off under certain of its derivative agreements related to potential termination fees and amounts payable under the agreements, if a termination were to occur.

Fair Value Measurement of Financial Instruments

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value Measurement of Financial Instruments

Piedmont considers its cash and cash equivalents, tenant receivables, notes receivable, restricted cash and escrows, accounts payable and accrued expenses, interest rate swap agreements, and debt to meet the definition of financial instruments. The following table sets forth the carrying and estimated fair value for each of Piedmont’s financial instruments, as well as its level within the GAAP fair value hierarchy, as of March 31, 2018 and December 31, 2017, respectively (in thousands):



	March 31, 2018					December 31, 2017
Financial Instrument	Carrying Value		Estimated Fair Value		Level Within Fair Value Hierarchy	Carrying Value		Estimated Fair Value		Level Within Fair Value Hierarchy
Assets:
Cash and cash equivalents⁽¹⁾	$	6,729	$	6,729	Level 1	$	7,382	$	7,382	Level 1
Tenant receivables, net⁽¹⁾	$	12,040	$	12,040	Level 1	$	12,139	$	12,139	Level 1
Notes receivable ⁽¹⁾(see Note 9)	$	3,200	$	3,200	Level 1	$	—	$	—	Level 1
Restricted cash and escrows⁽¹⁾	$	1,464	$	1,464	Level 1	$	1,373	$	1,373	Level 1
Interest rate swaps	$	725	$	725	Level 2	$	688	$	688	Level 2
Liabilities:
Accounts payable and accrued expenses⁽¹⁾	$	10,222	$	10,222	Level 1	$	126,429	$	126,429	Level 1
Interest rate swaps	$	222	$	222	Level 2	$	1,478	$	1,478	Level 2
Debt, net	$	1,689,644	$	1,701,284	Level 2	$	1,726,927	$	1,759,905	Level 2


⁽¹⁾	For the periods presented, the carrying value of these financial instruments approximates estimated fair value due to their short-term maturity.

Piedmont's debt was carried at book value as of March 31, 2018 and December 31, 2017; however, Piedmont's estimate of its estimated fair value is disclosed in the table above. Piedmont uses widely accepted valuation techniques including discounted cash flow analysis based on the contractual terms of the debt facilities, including the period to maturity of each instrument, and uses observable market-based inputs for similar debt facilities which have transacted recently in the market. Therefore, the estimated fair values determined are considered to be based on significant other observable inputs (Level 2). Scaling adjustments are made to these inputs to make them applicable to the remaining life of Piedmont's outstanding debt. Piedmont has not changed its valuation technique for estimating the fair value of its debt.

Piedmont’s interest rate swap agreements presented above, and further discussed in Note 6, are classified as “Interest rate swap” assets and liabilities in the accompanying consolidated balance sheets and were carried at estimated fair value as of March 31, 2018 and December 31, 2017. The valuation of these derivative instruments was determined using widely accepted valuation techniques including discounted cash flow analysis based on the contractual terms of the derivatives, including the period to maturity of each instrument, and uses observable market-based inputs, including interest rate curves and implied volatilities. Therefore, the estimated fair values determined are considered to be based on significant other observable inputs (Level 2). In addition, Piedmont considered both its own and the respective counterparties’ risk of nonperformance in determining the estimated fair value of its derivative financial instruments by estimating the current and potential future exposure under the derivative financial instruments that both Piedmont and the counterparties were at risk for as of the valuation date. The credit risk of Piedmont and its counterparties were factored into the calculation of the estimated fair value of the interest rate swaps; however, as of March 31, 2018 and December 31, 2017, this credit valuation adjustment did not comprise a material portion of the estimated fair value. Therefore, Piedmont believes that any unobservable inputs used to determine the estimated fair values of its derivative financial instruments are not significant to the fair value measurements in their entirety, and does not consider any of its derivative financial instruments to be Level 3 assets or liabilities.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Commitments and Contingencies	3 Months Ended
Commitments and Contingencies	Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments Under Existing Lease Agreements Under its existing lease agreements, Piedmont may be required to fund significant tenant improvements, leasing commissions, and building improvements. In addition, certain agreements contain provisions that require Piedmont to issue corporate or property guarantees to provide funding for capital improvements or other financial obligations. Piedmont classifies its capital improvements into two categories: (i) improvements which maintain the building's existing asset value and its revenue generating capacity (“non-incremental capital expenditures”) and (ii) improvements which incrementally enhance the building's asset value by expanding its revenue generating capacity (“incremental capital expenditures”). As of March 31, 2018, commitments to fund potential non-incremental capital expenditures over the next five years for tenant improvements totaled approximately $34.7 million related to Piedmont's existing lease portfolio over the respective lease terms, the majority of which Piedmont estimates may be required to be funded over the next three years based on when the underlying leases commence. For most of Piedmont’s leases, the timing of the actual funding of these tenant improvements is largely dependent upon tenant requests for reimbursement. In some cases, these obligations may expire with the leases without further recourse to Piedmont. As of March 31, 2018, commitments for incremental capital expenditures for tenant improvements associated with executed leases totaled approximately $12.5 million. Contingencies Related to Tenant Audits/Disputes Certain lease agreements include provisions that grant tenants the right to engage independent auditors to audit their annual operating expense reconciliations. Such audits may result in the re-interpretation of language in the lease agreements which could result in the refund of previously recognized tenant reimbursement revenues, resulting in financial loss to Piedmont. Piedmont recorded $0.4 million and $0.2 million of such reductions in reimbursement revenues related to such tenant audits/disputes during the three months ended March 31, 2018 and 2017, respectively.

Property Dispositions and Assets Held for Sale

3 Months Ended

Mar. 31, 2018

Discontinued Operations and Disposal Groups [Abstract]

Property Dispositions and Assets Held for Sale

During the three months ended March 31, 2018, Piedmont sold the following 14 properties (collectively, the "2017 Disposition Portfolio"):



Building		Location
Desert Canyon 300		Phoenix, Arizona
Windy Point I & II		Schaumburg, Illinois
2300 Cabot Drive		Lisle, Illinois
1075 West Entrance Drive		Auburn Hills, Michigan
Auburn Hills Corporate Center		Auburn Hills, Michigan
5301 Maryland Way		Brentwood, Tennessee
Suwanee Gateway One		Suwanee, Georgia
5601 Hiatus Road		Tamarac, Florida
2001 NW 64th Street		Fort Lauderdale, Florida
Piedmont Pointe I & II		Bethesda, Maryland
1200 Crown Colony Drive		Quincy, Massachusetts
2120 West End Avenue		Nashville, Tennessee

The sale did not meet the criteria to be reported as discontinued operations, therefore the operational results for these properties prior to the sale date are presented as continuing operations in the accompanying consolidated statements of income, and the $45.2 million gain on sale is presented separately on the face of the income statement. In addition to the $415.1 million in net sales proceeds received in cash, Piedmont also accepted a secured promissory note from the buyer for $3.2 million owed on the sale. The note bears interest at 7% per annum and has a maturity date of June 30, 2018, with two six month extensions requiring a fee of 25 basis points for each extension, with prepayment available at any time without penalty.

Assets Held for Sale

During the fourth quarter 2017, the 2017 Disposition Portfolio (described above) met the criteria for held for sale classification, and such properties are shown as held for sale as of December 31, 2017 in the consolidated balance sheet. No properties met the criteria for held for sale classification as of March 31, 2018. Details of assets held for sale as of March 31, 2018 and December 31, 2017 are presented below (in thousands):



	March 31, 2018		December 31, 2017
Real estate assets held for sale, net:
Land	$	—	$	74,498
Building and improvements, less accumulated depreciation of $0 and $169,116 as of March 31, 2018 and December 31, 2017, respectively	—		255,634
Construction in progress	—		2,278
Total real estate assets held for sale, net	$	—	$	332,410

Other assets held for sale, net:
Straight-line rent receivables	$	—	$	25,975
Prepaid expenses and other assets	—		328
Deferred lease costs, less accumulated amortization of $0 and $16,549 as of March 31, 2018 and December 31, 2017, respectively	—		20,828
Total other assets held for sale, net	$	—	$	47,131

Other liabilities held for sale, net:
Intangible lease liabilities, less accumulated amortization of $0 and $935 as of March 31, 2018 and December 31, 2017, respectively	$	—	$	380

Stock Based Compensation

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock Based Compensation

The Compensation Committee of Piedmont's Board of Directors has periodically granted deferred stock awards to all of Piedmont's employees and independent directors. Employee awards typically vest ratably over a multi-year period and independent director awards vest over one year. Certain employees' long-term equity incentive program is split equally between the time-vested awards described above and a multi-year performance share program whereby the actual awards are contingent upon Piedmont's total stockholder return ("TSR") relative to a peer group's TSR. The peer group is predetermined by the Board of Directors. Any shares earned are awarded at the end of the multi-year performance period and vest upon award.

A rollforward of Piedmont's equity based award activity for the three months ended March 31, 2018 is as follows:



	Shares		Weighted-Average Grant Date Fair Value
Unvested and Potential Stock Awards as of December 31, 2017	868,437		$	21.69
Decrease in Estimated Potential Share Award	(17,176	)	$	24.70
Performance Stock Awards Vested	(149,812	)	$	18.42
Deferred Stock Awards Vested	(38,883	)	$	18.60
Deferred Stock Awards Forfeited	(5,064	)	$	20.19
Unvested and Potential Stock Awards as of March 31, 2018	657,502		$	22.85

The following table provides additional information regarding stock award activity during the three months ended March 31, 2018 and 2017, respectively (in thousands, except per share amounts):



	Three Months Ended
	March 31, 2018		March 31, 2017
Total Grant Date Fair Value of Deferred Stock Vested During the Period	$	723	$	290
Share-based Liability Awards Paid During the Period⁽¹⁾	$	2,947	$	2,606


⁽¹⁾	Amounts reflect the issuance of performance share awards related to the 2014-16 and 2015-17 Performance Share Plans during the three months ended March 31, 2018 and 2017, respectively.

A detail of Piedmont’s outstanding stock awards as of March 31, 2018 is as follows:



Date of grant	Type of Award	Net Shares Granted ⁽¹⁾	Grant Date Fair Value		Vesting Schedule	Unvested Shares
January 3, 2014	Deferred Stock Award	65,252	$	16.45	Of the shares granted, 20% vested or will vest on January 3, 2015, 2016, 2017, 2018, and 2019, respectively.	16,416
May 1, 2015	Deferred Stock Award	214,891	$	17.59	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 1, 2016, 2017, and 2018, respectively.	61,923
May 24, 2016	Deferred Stock Award	230,309	$	19.91	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 24, 2017, 2018, and 2019, respectively.	122,470
May 24, 2016	Fiscal Year 2016-2018 Performance Share Program	—	$	23.02	Shares awarded, if any, will vest immediately upon determination of award in 2019.	100,171	⁽²⁾
May 18, 2017	Deferred Stock Award-Board of Directors	26,187	$	21.38	Of the shares granted, 100% will vest by May 18, 2018.	26,187
May 18, 2017	Deferred Stock Award	242,742	$	21.38	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 18, 2018, 2019, and 2020, respectively.	187,000
May 18, 2017	Fiscal Year 2017-2019 Performance Share Program	—	$	30.45	Shares awarded, if any, will vest immediately upon determination of award in 2020.	143,335	⁽²⁾
Total						657,502


⁽¹⁾	Amounts reflect the total grant to employees and independent directors, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through March 31, 2018.


⁽²⁾	Estimated based on Piedmont's cumulative TSR for the respective performance period through March 31, 2018. Share estimates are subject to change in future periods based upon Piedmont's relative performance compared to its peers' total stockholder return.

During the three months ended March 31, 2018 and 2017, Piedmont recognized approximately $1.0 million and $3.2 million of compensation expense related to stock awards, all of which is related to the amortization of unvested shares. During the three months ended March 31, 2018, a net total of 148,093 shares were issued to employees. As of March 31, 2018, approximately $2.6 million of unrecognized compensation cost related to unvested deferred stock awards remained, which Piedmont will record in its consolidated statements of income over a weighted-average vesting period of approximately one year.

Supplemental Disclosures for the Statement of Consolidated Cash Flows

3 Months Ended

Mar. 31, 2018

Supplemental Cash Flow Elements [Abstract]

Supplemental Disclosures for the Statement of Consolidated Cash Flows

Certain noncash investing and financing activities for the three months ended March 31, 2018 and 2017, (in thousands) are outlined below:



	Three Months Ended
	March 31, 2018			March 31, 2017
Accrued capital expenditures and deferred lease costs	$	6,222		$	12,478
Change in accrued dividends and discount on dividend reinvestments	$	(101,800	)	$	(30,532	)
Change in accrued share repurchases as part of an announced plan	$	(1,276	)	$	—
Accrued deferred financing costs	$	44		$	—

The following table provides a reconciliation of cash, cash equivalents, and restricted cash and escrows reported within the consolidated balance sheets that sum to the total of the same such amounts in the consolidated statement of cash flows as of the periods ended March 31, 2018 and December 31, 2017 (in thousands).



	March 31, 2018		December 31, 2017
Cash and cash equivalents	$	6,729	$	7,382
Restricted cash and escrows:
Real estate tax and escrowed cash	927		833
Security and utility deposit escrows	537		540
Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows	$	8,193	$	8,755

Amounts in real estate tax and escrowed cash represent deposits which are required by Piedmont’s lenders under certain of its debt agreements to escrow amounts for the payment of real estate taxes, and other amounts escrowed, for instance, earnest money deposited for the purchase of a property. Security and utility deposit escrows represent the cash held for tenants and/or Piedmont for lease related deposits.

Earnings Per Share

3 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Earnings Per Share

There are no adjustments to “Net income applicable to Piedmont” for the diluted earnings per share computations.

Net income per share-basic is calculated as net income available to common stockholders divided by the weighted average number of common shares outstanding during the period. Net income per share-diluted is calculated as net income available to common stockholders divided by the diluted weighted average number of common shares outstanding during the period, including unvested deferred stock awards. Diluted weighted average number of common shares reflects the potential dilution under the treasury stock method that would occur if the remaining unvested deferred stock awards vested and resulted in additional common shares outstanding. Unvested deferred stock awards which are determined to be anti-dilutive are not included in the calculation of diluted weighted average common shares.

The following table reconciles the denominator for the basic and diluted earnings per share computations shown on the consolidated statements of income for the three months ended March 31, 2018 and 2017, respectively (in thousands):



	Three Months Ended
	March 31, 2018	March 31, 2017
Weighted-average common shares – basic	135,877	145,287
Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards	306	546
Weighted-average common shares – diluted	136,183	145,833

Common stock issued and outstanding as of period end	130,025	145,320

Guarantor and Non-Guarantor Financial Information

3 Months Ended

Mar. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Guarantor and Non-Guarantor Financial Information

The following condensed consolidating financial information for Piedmont (the "Parent", "Guarantor", and/or "Consolidated"), Piedmont OP (the "Issuer"), and the other directly and indirectly owned subsidiaries of Piedmont as the Guarantor (the "Non-Guarantors") is provided pursuant to the requirements of Rule 3-10 of Regulation S-X regarding financial statements of guarantors and issuers of guaranteed registered securities. The Issuer is a wholly-owned subsidiary of the Guarantor, and all guarantees by the Guarantor of securities issued by the Issuer are full and unconditional. The principal elimination entries relate to investments in subsidiaries and intercompany balances and transactions, including transactions with the Non-Guarantors.



Condensed Consolidating Balance Sheets
As of March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations			Piedmont (Consolidated)
Assets:
Real estate assets, at cost:
Land	$	—	$	36,094	$	511,508	$	—		$	547,602
Buildings and improvements, less accumulated depreciation	—		178,181		2,246,689		(300		)	2,424,570
Intangible lease assets, less accumulated amortization	—		45		75,230		—			75,275
Construction in progress	—		390		14,836		—			15,226
Total real estate assets	—		214,710		2,848,263		(300		)	3,062,673
Cash and cash equivalents	150		4,017		2,562		—			6,729
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	—		16,870		162,715		—			179,585
Investment in subsidiaries	1,790,277		2,808,205		171		(4,598,653		)	—
Notes receivable	—		810		147,700		(145,310		)	3,200
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	116		8,864		18,251		(14		)	27,217
Goodwill	—		98,918		—		—			98,918
Deferred lease costs, net	—		15,976		241,392		—			257,368
Total assets	$	1,790,543	$	3,168,370	$	3,421,054	$	(4,744,277	)	$	3,635,690
Liabilities:
Debt, net	$	—	$	1,498,271	$	336,683	$	(145,310	)	$	1,689,644
Accounts payable, accrued expenses, and accrued capital expenditures	955		14,028		68,817		(14		)	83,786
Deferred income	—		2,757		26,994		—			29,751
Intangible lease liabilities, net	—		—		42,699		—			42,699
Interest rate swaps	—		222		—		—			222
Total liabilities	955		1,515,278		475,193		(145,324		)	1,846,102
Equity:
Total stockholders’ equity	1,789,588		1,653,092		2,945,861		(4,598,953		)	1,789,588
Total liabilities and stockholders’ equity	$	1,790,543	$	3,168,370	$	3,421,054	$	(4,744,277	)	$	3,635,690



Condensed Consolidating Balance Sheets
As of December 31, 2017
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)		Non-Guarantors		Eliminations			Piedmont (Consolidated)
Assets:
Real estate assets, at cost:
Land	$	—		$	36,094	$	508,700	$	—		$	544,794
Buildings and improvements, less accumulated depreciation	—			180,886		2,237,437		(300		)	2,418,023
Intangible lease assets, less accumulated amortization	—			181		77,624		—			77,805
Construction in progress	—			85		11,625		—			11,710
Real estate assets held for sale, net	—			32,815		299,595		—			332,410
Total real estate assets	—			250,061		3,134,981		(300		)	3,384,742
Cash and cash equivalents	150			3,890		3,342		—			7,382
Tenant and straight-line rent receivables, net, and amounts due from unconsolidated joint ventures	—			16,891		158,418		—			175,309
Advances to affiliates	1,674,276			6,297,632		—		(7,971,908		)	—
Investment in subsidiary	3,437,299			—		172		(3,437,471		)	—
Notes receivable	—			88,810		144,500		(233,310		)	—
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	2			5,094		20,222		(740		)	24,578
Goodwill	—			98,918		—		—			98,918
Deferred lease costs, net	—			16,611		245,296		—			261,907
Other assets held for sale, net	—			2,266		44,865		—			47,131
Total assets	$	5,111,727		$	6,780,173	$	3,751,796	$	(11,643,729	)	$	3,999,967
Liabilities:
Debt, net	$	—		$	1,535,239	$	424,998	$	(233,310	)	$	1,726,927
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	104,028			20,279		93,086		(740		)	216,653
Advances from affiliates	5,277,957			941,494		1,850,712		(8,070,163		)	—
Deferred income	—			3,631		25,951		—			29,582
Intangible lease liabilities, net	—			—		38,458		—			38,458
Interest rate swaps	—			1,478		—		—			1,478
Liabilities held for sale, net	—			—		380		—			380
Total liabilities	5,381,985			2,502,121		2,433,585		(8,304,213		)	2,013,478
Equity:
Total stockholders’ equity	(270,258		)	4,278,052		1,318,211		(3,339,516		)	1,986,489
Total liabilities and stockholders’ equity	$	5,111,727		$	6,780,173	$	3,751,796	$	(11,643,729	)	$	3,999,967



Condensed Consolidating Statements of Income
For the three months ended March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations			Consolidated
Revenues:
Rental income	$	—		$	8,815		$	93,071		$	(432	)	$	101,454
Tenant reimbursements	—			2,646			20,432			(84		)	22,994
Property management fee revenue	—			—			4,181			(3,872		)	309
Other property related revenue	—			27			5,116			—			5,143
	—			11,488			122,800			(4,388		)	129,900
Expenses:
Property operating costs	—			4,713			51,534			(4,388		)	51,859
Depreciation	—			2,865			24,280			—			27,145
Amortization	—			611			16,122			—			16,733
General and administrative	100			1,887			4,565			—			6,552
	100			10,076			96,501			(4,388		)	102,289
Real estate operating income/(loss)	(100		)	1,412			26,299			—			27,611
Other income (expense):
Interest expense	—			(12,021		)	(3,699		)	1,962			(13,758		)
Other income/(expense)	—			124			2,284			(1,962		)	446
Loss on extinguishment of debt	—			(1,680		)	—			—			(1,680		)
Gain on sale of real estate assets	—			1,430			43,779			—			45,209
	—			(12,147		)	42,364			—			30,217
Income/(loss) before consolidated subsidiaries	(100		)	(10,735		)	68,663			—			57,828
Income/(loss) from subsidiaries	57,930			67,669			—			(125,599		)	—
Net income/(loss)	57,830			56,934			68,663			(125,599		)	57,828
Plus: Net loss applicable to noncontrolling interest	—			—			2			—			2
Net income/(loss) applicable to Piedmont	$	57,830		$	56,934		$	68,665		$	(125,599	)	$	57,830



Condensed Consolidating Statements of Income
For the three months ended March 31, 2017
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations			Consolidated
Revenues:
Rental income	$	—		$	11,388		$	107,109		$	(458	)	$	118,039
Tenant reimbursements	—			3,005			21,936			(104		)	24,837
Property management fee revenue	—			—			4,636			(4,111		)	525
Other property related revenue	—			32			5,030			—			5,062
	—			14,425			138,711			(4,673		)	148,463
Expenses:
Property operating costs	—			5,802			54,701			(4,673		)	55,830
Depreciation	—			3,463			27,305			—			30,768
Amortization	—			856			19,559			—			20,415
General and administrative	103			1,702			6,345			—			8,150
	103			11,823			107,910			(4,673		)	115,163
Real estate operating income/(loss)	(103		)	2,602			30,801			—			33,300
Other income (expense):
Interest expense	—			(14,444		)	(7,251		)	3,638			(18,057		)
Other income/(expense)	—			2,229			1,309			(3,638		)	(100		)
Equity in income of unconsolidated joint ventures	—			11			—			—			11
Gain/(loss) on sale of real estate assets	—			(61		)	8			—			(53		)
Net income/(loss)	(103		)	(9,663		)	24,867			—			15,101
Plus: Net loss applicable to noncontrolling interest	—			—			3			—			3
Net income/(loss) applicable to Piedmont	$	(103	)	$	(9,663	)	$	24,870		$	—		$	15,104



Consolidating Statements of Comprehensive Income
For the Three Months Ended March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations			Piedmont (Consolidated)
Net income	$	57,830	$	56,934	$	68,665	$	(125,599	)	$	57,830
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,517		1,517		—		(1,517		)	1,517
Plus: Reclassification of net loss included in net income	1,052		1,052		—		(1,052		)	1,052
Other comprehensive income	2,569		2,569		—		(2,569		)	2,569

Comprehensive income	$	60,399	$	59,503	$	68,665	$	(128,168	)	$	60,399



Condensed Consolidating Statements of Cash Flows
For the three months ended March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations			Piedmont (Consolidated)
Net Cash Provided by/(Used in) Operating Activities	$	58,739		$	56,468		$	43,698		$	(125,595	)	$	33,310

Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	—			(2,004		)	(38,903		)	—			(40,907		)
Intercompany note receivable	—			88,000			—			(88,000		)	—
Net sales proceeds from wholly-owned properties	—			32,086			382,992			—			415,078
Note receivable issuance	—			—			(3,200		)	—			(3,200		)
Deferred lease costs paid	—			(5		)	(2,591		)	—			(2,596		)
Distributions from subsidiaries	305,266			62,437			—			(367,703		)	—
Net cash provided by investing activities	305,266			180,514			338,298			(455,703		)	368,375
Cash Flows from Financing Activities:
Debt issuance costs paid	—			(101		)	—			—			(101		)
Proceeds from debt	—			716,225			—			—			716,225
Repayments of debt	—			(754,000		)	(359		)	—			(754,359		)
Intercompany note payable	—			—			(88,000		)	88,000			—
Value of shares withheld to pay tax obligations related to employee stock compensation	(737		)	—			—			—			(737		)
Repurchases of common stock as part of announced plan	(233,164		)	—			—			—			(233,164		)
Distributions	(130,104		)	(198,964		)	(294,341		)	493,298			(130,111		)
Net cash used in financing activities	(364,005		)	(236,840		)	(382,700		)	581,298			(402,247		)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—			142			(704		)	—			(562		)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150			3,906			4,699			—			8,755
Cash, cash equivalents, and restricted cash and escrows, end of period	$	150		$	4,048		$	3,995		$	—		$	8,193



Condensed Consolidating Statements of Cash Flows
For the three months ended March 31, 2017
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations		Piedmont (Consolidated)
Net Cash Provided by/(Used in) Operating Activities	$	998		$	(5,748	)	$	55,044		$	—	$	50,294

Cash Flows from Investing Activities:
Investment in real estate assets, consolidated joint venture, and real estate related intangibles, net of accruals	—			(407		)	(27,796		)	—		(28,203		)
Investments in unconsolidated joint ventures	—			(284		)	—			—		(284		)
Net sales proceeds from wholly-owned properties	—			(58		)	(6		)	—		(64		)
Deferred lease costs paid	—			(305		)	(3,965		)	—		(4,270		)
Net cash provided by/(used in) investing activities	—			(1,054		)	(31,767		)	—		(32,821		)
Cash Flows from Financing Activities:
Debt issuance costs paid	—			(63		)	—			—		(63		)
Proceeds from debt	—			100,000			—			—		100,000
Repayments of debt	—			(55,000		)	(345		)	—		(55,345		)
Value of shares withheld to pay tax obligations related to employee stock compensation	(1,128		)	—			—			—		(1,128		)
(Distributions to)/repayments from affiliates	61,210			(38,103		)	(23,107		)	—		—
Dividends paid and discount on dividend reinvestments	(61,080		)	—			—			—		(61,080		)
Net cash provided by/(used in) financing activities	(998		)	6,834			(23,452		)	—		(17,616		)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—			32			(175		)	—		(143		)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150			3,693			4,361			—		8,204
Cash, cash equivalents, and restricted cash and escrows, end of period	$	150		$	3,725		$	4,186		$	—	$	8,061

Subsequent Events	3 Months Ended
Subsequent Events	Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Second Quarter Dividend Declaration On May 1, 2018, the Board of Directors of Piedmont declared dividends for the second quarter 2018 in the amount of $0.21 per common share outstanding to stockholders of record as of the close of business on May 23, 2018. Such dividends are to be paid on June 15, 2018.

Summary of Significant Accounting Policies (Policies)

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Basis of Presentation

Principles of Consolidation

All intercompany balances and transactions have been eliminated upon consolidation.

Use of Estimates

Income Taxes

Tax Cuts and Jobs Act

Reclassifications

Recent Accounting Pronouncements

Accounting Pronouncements Adopted during the Quarter Ended March 31, 2018

Revenue Recognition



			(After Adoption of Revenue Recognition Amendments)
	Three Months Ended March 31, 2018		Three Months Ended March 31, 2017
Rental income	$	101,454	$	118,039
Tenant reimbursements	22,994		24,837
Property management fee revenue	309		525
Other property related income	5,143		5,062
Total revenues	$	129,900	$	148,463

Rental income - consists of revenue from leases with Piedmont's tenants, which is not within the scope of the Revenue Recognition Amendments.

Gain/(loss) on Sale of Real Estate Assets

Equity Investments Held in Non-qualified Deferred Compensation Plan

Interest Rate Derivatives

Other Recent Accounting Pronouncements

Risk Management Objective of Using Derivatives

- Definition

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.

+ References + Details

Summary of Significant Accounting Policies (Tables)

3 Months Ended

Mar. 31, 2018

Accounting Policies [Abstract]

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]



			(After Adoption of Revenue Recognition Amendments)
	Three Months Ended March 31, 2018		Three Months Ended March 31, 2017
Rental income	$	101,454	$	118,039
Tenant reimbursements	22,994		24,837
Property management fee revenue	309		525
Other property related income	5,143		5,062
Total revenues	$	129,900	$	148,463

Debt (Tables)

3 Months Ended

Mar. 31, 2018

Debt Disclosure [Abstract]

Schedule of Debt

The following table summarizes the terms of Piedmont’s indebtedness outstanding as of March 31, 2018 and December 31, 2017 (in thousands):



Facility ⁽¹⁾	Stated Rate		Effective Rate ⁽²⁾			Maturity		Amount Outstanding as of
Facility ⁽¹⁾	Stated Rate		Effective Rate ⁽²⁾			Maturity		March 31, 2018		December 31, 2017
Secured (Fixed)
$35 Million Fixed-Rate Loan ⁽³⁾	5.55	%	3.75	%		9/1/2021		$	30,434	$	30,670
$160 Million Fixed-Rate Loan ⁽⁴⁾	3.48	%	3.58	%		7/5/2022		160,000		160,000
Net premium and unamortized debt issuance costs								871		946
Subtotal/Weighted Average ⁽⁵⁾	3.81	%						191,305		191,616
Unsecured (Variable and Fixed)
$170 Million Unsecured 2015 Term Loan	LIBOR + 1.125%		2.54	%		5/15/2018		—		170,000
$300 Million Unsecured 2013 Term Loan	LIBOR + 1.20%		2.78	%	⁽⁸⁾	1/31/2019		—		300,000
$500 Million Unsecured 2015 Line of Credit	LIBOR + 1.00%		2.87	%	⁽⁶⁾	6/18/2019	⁽⁹⁾	207,000		23,000
$300 Million Unsecured 2011 Term Loan	LIBOR + 1.15%		3.35	%	⁽⁸⁾	1/15/2020		300,000		300,000
$350 Million Senior Notes	3.40	%	3.43	%		6/01/2023		350,000		350,000
$400 Million Senior Notes	4.45	%	4.10	%		3/15/2024		400,000		400,000
$250 Million Unsecured 2018 Term Loan ⁽⁶⁾	LIBOR + 1.60%		3.86	%	⁽¹⁰⁾	3/31/2025		250,000		—
Discounts and unamortized debt issuance costs ⁽⁷⁾								(8,661)		(7,689)
Subtotal/Weighted Average ⁽⁵⁾	3.67	%						1,498,339		1,535,311
Total/Weighted Average ⁽⁵⁾	3.69	%						$	1,689,644	$	1,726,927


⁽¹⁾	Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of March 31, 2018 and December 31, 2017 is interest-only.


⁽²⁾	Effective rate after consideration of settled or in-place interest rate swap agreements, issuance premiums/discounts, and/or fair market value adjustments upon assumption of debt.


⁽³⁾	Collateralized by the 5 Wall Street building in Burlington, Massachusetts.


⁽⁴⁾	Collateralized by the 1901 Market Street building in Philadelphia, Pennsylvania.


⁽⁵⁾	Weighted average is based on contractual balance of outstanding debt and the stated or effectively fixed interest rates as of March 31, 2018.


⁽⁶⁾	On a periodic basis, Piedmont may select from multiple interest rate options, including the prime rate and various-length LIBOR locks on all or a portion of the principal. All LIBOR selections are subject to an additional spread over the selected rate based on Piedmont’s current credit rating.


⁽⁷⁾	As a result of repaying the $170 Million Unsecured 2015 Term Loan and the $300 Million Unsecured 2013 Term Loan in January 2018, Piedmont recorded a loss on extinguishment of debt of approximately $0.4 million related to the write-off of associated discounts and unamortized debt issuance costs.


⁽⁸⁾	The facility has a stated variable rate; however, Piedmont has entered into interest rate swap agreements which effectively fix, exclusive of Piedmont's credit rating, the rate shown as the effective rate.


⁽⁹⁾	Piedmont may extend the term for up to one additional year (through two available six month extensions to a final extended maturity date of June 18, 2020) provided Piedmont is not then in default and upon payment of extension fees.

⁽¹⁰⁾

Variable Interest Entities (Tables)

3 Months Ended

Mar. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Schedule of Variable Interest Entities

A summary of Piedmont’s interests in its consolidated VIEs and their related carrying values as of March 31, 2018 and December 31, 2017 is as follows (net carrying amount in millions):



Entity	Piedmont’s % Ownership of Entity	Related Building	Net Carrying Amount as of March 31, 2018		Net Carrying Amount as of December 31, 2017		Primary Beneficiary Considerations
1201 Eye Street N.W. Associates, LLC	98.6%	1201 Eye Street	$	83.7	$	81.1	In accordance with the partnership’s governing documents, Piedmont currently receives 100% of the cash flow of the entity and has sole discretion in directing the management and leasing activities of the building.
1225 Eye Street N.W. Associates, LLC	98.1%	1225 Eye Street	$	64.3	$	65.2	In accordance with the partnership’s governing documents, Piedmont currently receives 100% of the cash flow of the entity and has sole discretion in directing the management and leasing activities of the building.
Piedmont 500 W. Monroe Fee, LLC	100%	500 W. Monroe	$	260.8	$	263.2	The Omnibus Agreement with the previous owner includes equity participation rights upon sale of the property for the previous owner, if certain financial returns are achieved; however, Piedmont has sole decision making authority and is entitled to 100% of the economic benefits of the property until such returns are met.

- Definition

Tabular disclosure of the significant judgments and assumptions made in determining whether a variable interest (as defined) held by the entity requires the variable interest entity (VIE) (as defined) to be consolidated and (or) disclose information about its involvement with the VIE, individually or in aggregate (as applicable); the nature of restrictions, if any, on the consolidated VIE's assets and on the settlement of its liabilities reported by an entity in its statement of financial position, including the carrying amounts of such assets and liabilities; the nature of, and changes in, the risks associated with involvement in the VIE; how involvement with the VIE affects the entity's financial position, financial performance, and cash flows; the lack of recourse if creditors (or beneficial interest holders) of the consolidated VIE have no recourse to the general credit of the primary beneficiary (if applicable); the terms of arrangements, giving consideration to both explicit arrangements and implicit variable interests, if any, that could require the entity to provide financial support to the VIE, including events or circumstances that could expose the entity to a loss; the methodology used by the entity for determining whether or not it is the primary beneficiary of the variable interest entity; the significant factors considered and judgments made in determining that the power to direct the activities of a VIE that most significantly impact the VIE's economic performance are shared (as defined); the carrying amounts and classification of assets and liabilities of the VIE included in the statement of financial position; the entity's maximum exposure to loss, if any, as a result of its involvement with the VIE, including how the maximum exposure is determined and significant sources of the entity's exposure to the VIE; a comparison of the carrying amounts of the assets and liabilities and the entity's maximum exposure to loss; information about any liquidity arrangements, guarantees, and (or) other commitments by third parties that may affect the fair value or risk of the entity's variable interest in the VIE; whether or not the entity has provided financial support or other support (explicitly or implicitly) to the VIE that it was not previously contractually required to provide or whether the entity intends to provide that support, including the type and amount of the support and the primary reasons for providing the support; and supplemental information the entity determines necessary to provide.

+ References + Details

Derivative Instruments (Tables)

3 Months Ended

Mar. 31, 2018

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Notional Amounts of Outstanding Derivative Positions

A detail of Piedmont’s interest rate derivatives outstanding as of March 31, 2018 is as follows:

Interest Rate Derivatives:

Number of Swap Agreements

Associated Debt Instrument

Total Notional Amount

(in millions)

Effective Date

Maturity Date

Interest rate swaps

$300 Million Unsecured 2011 Term Loan

300

11/22/2016

1/15/2020

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

100

3/29/2018

3/31/2025

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

3/29/2018

3/29/2020

Total

450

Schedule of Interest Rate Derivatives

A detail of Piedmont’s interest rate derivatives on a gross and net basis as of March 31, 2018 and December 31, 2017, respectively, is as follows (in thousands):



Interest rate swaps classified as:	March 31, 2018			December 31, 2017
Gross derivative assets	$	725		$	688
Gross derivative liabilities	(222		)	(1,478		)
Net derivative asset/(liability)	$	503		$	(790	)

Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)



	Three Months Ended
Interest Rate Swaps in Cash Flow Hedging Relationships	March 31, 2018		March 31, 2017
Amount of gain recognized in OCI	$	1,517	$	1,044
Amount of previously recorded gain/(loss) reclassified from OCI into Interest Expense	$	206	$	(1,306	)
Amount of loss recognized in Other Income/(Expense) on derivatives from OCI into Loss on Extinguishment of Debt	$	1,258	$	—

Total amount of Interest Expense presented in the consolidated statements of income	$	13,758	$	18,057
Total amount of Loss on Extinguishment of Debt presented in the consolidated statements of income	$	1,680	$	—

Fair Value Measurement of Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Fair Value, by Balance Sheet Grouping

The following table sets forth the carrying and estimated fair value for each of Piedmont’s financial instruments, as well as its level within the GAAP fair value hierarchy, as of March 31, 2018 and December 31, 2017, respectively (in thousands):



	March 31, 2018					December 31, 2017
Financial Instrument	Carrying Value		Estimated Fair Value		Level Within Fair Value Hierarchy	Carrying Value		Estimated Fair Value		Level Within Fair Value Hierarchy
Assets:
Cash and cash equivalents⁽¹⁾	$	6,729	$	6,729	Level 1	$	7,382	$	7,382	Level 1
Tenant receivables, net⁽¹⁾	$	12,040	$	12,040	Level 1	$	12,139	$	12,139	Level 1
Notes receivable ⁽¹⁾(see Note 9)	$	3,200	$	3,200	Level 1	$	—	$	—	Level 1
Restricted cash and escrows⁽¹⁾	$	1,464	$	1,464	Level 1	$	1,373	$	1,373	Level 1
Interest rate swaps	$	725	$	725	Level 2	$	688	$	688	Level 2
Liabilities:
Accounts payable and accrued expenses⁽¹⁾	$	10,222	$	10,222	Level 1	$	126,429	$	126,429	Level 1
Interest rate swaps	$	222	$	222	Level 2	$	1,478	$	1,478	Level 2
Debt, net	$	1,689,644	$	1,701,284	Level 2	$	1,726,927	$	1,759,905	Level 2


⁽¹⁾	For the periods presented, the carrying value of these financial instruments approximates estimated fair value due to their short-term maturity.

Property Dispositions and Assets Held for Sale (Tables)

3 Months Ended

Mar. 31, 2018

Discontinued Operations and Disposal Groups [Abstract]

Assets Held for Sale and Discontinued Operations

Details of assets held for sale as of March 31, 2018 and December 31, 2017 are presented below (in thousands):



	March 31, 2018		December 31, 2017
Real estate assets held for sale, net:
Land	$	—	$	74,498
Building and improvements, less accumulated depreciation of $0 and $169,116 as of March 31, 2018 and December 31, 2017, respectively	—		255,634
Construction in progress	—		2,278
Total real estate assets held for sale, net	$	—	$	332,410

Other assets held for sale, net:
Straight-line rent receivables	$	—	$	25,975
Prepaid expenses and other assets	—		328
Deferred lease costs, less accumulated amortization of $0 and $16,549 as of March 31, 2018 and December 31, 2017, respectively	—		20,828
Total other assets held for sale, net	$	—	$	47,131

Other liabilities held for sale, net:
Intangible lease liabilities, less accumulated amortization of $0 and $935 as of March 31, 2018 and December 31, 2017, respectively	$	—	$	380

Stock Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Nonvested Share Activity

A rollforward of Piedmont's equity based award activity for the three months ended March 31, 2018 is as follows:



	Shares		Weighted-Average Grant Date Fair Value
Unvested and Potential Stock Awards as of December 31, 2017	868,437		$	21.69
Decrease in Estimated Potential Share Award	(17,176	)	$	24.70
Performance Stock Awards Vested	(149,812	)	$	18.42
Deferred Stock Awards Vested	(38,883	)	$	18.60
Deferred Stock Awards Forfeited	(5,064	)	$	20.19
Unvested and Potential Stock Awards as of March 31, 2018	657,502		$	22.85

The following table provides additional information regarding stock award activity during the three months ended March 31, 2018 and 2017, respectively (in thousands, except per share amounts):



	Three Months Ended
	March 31, 2018		March 31, 2017
Total Grant Date Fair Value of Deferred Stock Vested During the Period	$	723	$	290
Share-based Liability Awards Paid During the Period⁽¹⁾	$	2,947	$	2,606


⁽¹⁾	Amounts reflect the issuance of performance share awards related to the 2014-16 and 2015-17 Performance Share Plans during the three months ended March 31, 2018 and 2017, respectively.

Schedule of Outstanding Employee Stock Awards

A detail of Piedmont’s outstanding stock awards as of March 31, 2018 is as follows:



Date of grant	Type of Award	Net Shares Granted ⁽¹⁾	Grant Date Fair Value		Vesting Schedule	Unvested Shares
January 3, 2014	Deferred Stock Award	65,252	$	16.45	Of the shares granted, 20% vested or will vest on January 3, 2015, 2016, 2017, 2018, and 2019, respectively.	16,416
May 1, 2015	Deferred Stock Award	214,891	$	17.59	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 1, 2016, 2017, and 2018, respectively.	61,923
May 24, 2016	Deferred Stock Award	230,309	$	19.91	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 24, 2017, 2018, and 2019, respectively.	122,470
May 24, 2016	Fiscal Year 2016-2018 Performance Share Program	—	$	23.02	Shares awarded, if any, will vest immediately upon determination of award in 2019.	100,171	⁽²⁾
May 18, 2017	Deferred Stock Award-Board of Directors	26,187	$	21.38	Of the shares granted, 100% will vest by May 18, 2018.	26,187
May 18, 2017	Deferred Stock Award	242,742	$	21.38	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 18, 2018, 2019, and 2020, respectively.	187,000
May 18, 2017	Fiscal Year 2017-2019 Performance Share Program	—	$	30.45	Shares awarded, if any, will vest immediately upon determination of award in 2020.	143,335	⁽²⁾
Total						657,502


⁽¹⁾	Amounts reflect the total grant to employees and independent directors, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through March 31, 2018.


⁽²⁾	Estimated based on Piedmont's cumulative TSR for the respective performance period through March 31, 2018. Share estimates are subject to change in future periods based upon Piedmont's relative performance compared to its peers' total stockholder return.

Supplemental Disclosures for the Statement of Consolidated Cash Flows (Tables)

3 Months Ended

Mar. 31, 2018

Supplemental Cash Flow Elements [Abstract]

Schedule of Cash Flow, Supplemental Disclosures

Certain noncash investing and financing activities for the three months ended March 31, 2018 and 2017, (in thousands) are outlined below:



	Three Months Ended
	March 31, 2018			March 31, 2017
Accrued capital expenditures and deferred lease costs	$	6,222		$	12,478
Change in accrued dividends and discount on dividend reinvestments	$	(101,800	)	$	(30,532	)
Change in accrued share repurchases as part of an announced plan	$	(1,276	)	$	—
Accrued deferred financing costs	$	44		$	—



	March 31, 2018		December 31, 2017
Cash and cash equivalents	$	6,729	$	7,382
Restricted cash and escrows:
Real estate tax and escrowed cash	927		833
Security and utility deposit escrows	537		540
Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows	$	8,193	$	8,755

Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2018

Earnings Per Share [Abstract]

Schedule of Weighted Average Number of Shares



	Three Months Ended
	March 31, 2018	March 31, 2017
Weighted-average common shares – basic	135,877	145,287
Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards	306	546
Weighted-average common shares – diluted	136,183	145,833

Common stock issued and outstanding as of period end	130,025	145,320

Guarantor and Non-Guarantor Financial Information (Tables)

3 Months Ended

Mar. 31, 2018

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Condensed Consolidated Balance Sheets



Condensed Consolidating Balance Sheets
As of March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations			Piedmont (Consolidated)
Assets:
Real estate assets, at cost:
Land	$	—	$	36,094	$	511,508	$	—		$	547,602
Buildings and improvements, less accumulated depreciation	—		178,181		2,246,689		(300		)	2,424,570
Intangible lease assets, less accumulated amortization	—		45		75,230		—			75,275
Construction in progress	—		390		14,836		—			15,226
Total real estate assets	—		214,710		2,848,263		(300		)	3,062,673
Cash and cash equivalents	150		4,017		2,562		—			6,729
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	—		16,870		162,715		—			179,585
Investment in subsidiaries	1,790,277		2,808,205		171		(4,598,653		)	—
Notes receivable	—		810		147,700		(145,310		)	3,200
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	116		8,864		18,251		(14		)	27,217
Goodwill	—		98,918		—		—			98,918
Deferred lease costs, net	—		15,976		241,392		—			257,368
Total assets	$	1,790,543	$	3,168,370	$	3,421,054	$	(4,744,277	)	$	3,635,690
Liabilities:
Debt, net	$	—	$	1,498,271	$	336,683	$	(145,310	)	$	1,689,644
Accounts payable, accrued expenses, and accrued capital expenditures	955		14,028		68,817		(14		)	83,786
Deferred income	—		2,757		26,994		—			29,751
Intangible lease liabilities, net	—		—		42,699		—			42,699
Interest rate swaps	—		222		—		—			222
Total liabilities	955		1,515,278		475,193		(145,324		)	1,846,102
Equity:
Total stockholders’ equity	1,789,588		1,653,092		2,945,861		(4,598,953		)	1,789,588
Total liabilities and stockholders’ equity	$	1,790,543	$	3,168,370	$	3,421,054	$	(4,744,277	)	$	3,635,690



Condensed Consolidating Balance Sheets
As of December 31, 2017
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)		Non-Guarantors		Eliminations			Piedmont (Consolidated)
Assets:
Real estate assets, at cost:
Land	$	—		$	36,094	$	508,700	$	—		$	544,794
Buildings and improvements, less accumulated depreciation	—			180,886		2,237,437		(300		)	2,418,023
Intangible lease assets, less accumulated amortization	—			181		77,624		—			77,805
Construction in progress	—			85		11,625		—			11,710
Real estate assets held for sale, net	—			32,815		299,595		—			332,410
Total real estate assets	—			250,061		3,134,981		(300		)	3,384,742
Cash and cash equivalents	150			3,890		3,342		—			7,382
Tenant and straight-line rent receivables, net, and amounts due from unconsolidated joint ventures	—			16,891		158,418		—			175,309
Advances to affiliates	1,674,276			6,297,632		—		(7,971,908		)	—
Investment in subsidiary	3,437,299			—		172		(3,437,471		)	—
Notes receivable	—			88,810		144,500		(233,310		)	—
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	2			5,094		20,222		(740		)	24,578
Goodwill	—			98,918		—		—			98,918
Deferred lease costs, net	—			16,611		245,296		—			261,907
Other assets held for sale, net	—			2,266		44,865		—			47,131
Total assets	$	5,111,727		$	6,780,173	$	3,751,796	$	(11,643,729	)	$	3,999,967
Liabilities:
Debt, net	$	—		$	1,535,239	$	424,998	$	(233,310	)	$	1,726,927
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	104,028			20,279		93,086		(740		)	216,653
Advances from affiliates	5,277,957			941,494		1,850,712		(8,070,163		)	—
Deferred income	—			3,631		25,951		—			29,582
Intangible lease liabilities, net	—			—		38,458		—			38,458
Interest rate swaps	—			1,478		—		—			1,478
Liabilities held for sale, net	—			—		380		—			380
Total liabilities	5,381,985			2,502,121		2,433,585		(8,304,213		)	2,013,478
Equity:
Total stockholders’ equity	(270,258		)	4,278,052		1,318,211		(3,339,516		)	1,986,489
Total liabilities and stockholders’ equity	$	5,111,727		$	6,780,173	$	3,751,796	$	(11,643,729	)	$	3,999,967

Condensed Consolidated Statements of Income



Condensed Consolidating Statements of Income
For the three months ended March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations			Consolidated
Revenues:
Rental income	$	—		$	8,815		$	93,071		$	(432	)	$	101,454
Tenant reimbursements	—			2,646			20,432			(84		)	22,994
Property management fee revenue	—			—			4,181			(3,872		)	309
Other property related revenue	—			27			5,116			—			5,143
	—			11,488			122,800			(4,388		)	129,900
Expenses:
Property operating costs	—			4,713			51,534			(4,388		)	51,859
Depreciation	—			2,865			24,280			—			27,145
Amortization	—			611			16,122			—			16,733
General and administrative	100			1,887			4,565			—			6,552
	100			10,076			96,501			(4,388		)	102,289
Real estate operating income/(loss)	(100		)	1,412			26,299			—			27,611
Other income (expense):
Interest expense	—			(12,021		)	(3,699		)	1,962			(13,758		)
Other income/(expense)	—			124			2,284			(1,962		)	446
Loss on extinguishment of debt	—			(1,680		)	—			—			(1,680		)
Gain on sale of real estate assets	—			1,430			43,779			—			45,209
	—			(12,147		)	42,364			—			30,217
Income/(loss) before consolidated subsidiaries	(100		)	(10,735		)	68,663			—			57,828
Income/(loss) from subsidiaries	57,930			67,669			—			(125,599		)	—
Net income/(loss)	57,830			56,934			68,663			(125,599		)	57,828
Plus: Net loss applicable to noncontrolling interest	—			—			2			—			2
Net income/(loss) applicable to Piedmont	$	57,830		$	56,934		$	68,665		$	(125,599	)	$	57,830



Condensed Consolidating Statements of Income
For the three months ended March 31, 2017
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations			Consolidated
Revenues:
Rental income	$	—		$	11,388		$	107,109		$	(458	)	$	118,039
Tenant reimbursements	—			3,005			21,936			(104		)	24,837
Property management fee revenue	—			—			4,636			(4,111		)	525
Other property related revenue	—			32			5,030			—			5,062
	—			14,425			138,711			(4,673		)	148,463
Expenses:
Property operating costs	—			5,802			54,701			(4,673		)	55,830
Depreciation	—			3,463			27,305			—			30,768
Amortization	—			856			19,559			—			20,415
General and administrative	103			1,702			6,345			—			8,150
	103			11,823			107,910			(4,673		)	115,163
Real estate operating income/(loss)	(103		)	2,602			30,801			—			33,300
Other income (expense):
Interest expense	—			(14,444		)	(7,251		)	3,638			(18,057		)
Other income/(expense)	—			2,229			1,309			(3,638		)	(100		)
Equity in income of unconsolidated joint ventures	—			11			—			—			11
Gain/(loss) on sale of real estate assets	—			(61		)	8			—			(53		)
Net income/(loss)	(103		)	(9,663		)	24,867			—			15,101
Plus: Net loss applicable to noncontrolling interest	—			—			3			—			3
Net income/(loss) applicable to Piedmont	$	(103	)	$	(9,663	)	$	24,870		$	—		$	15,104

Condensed Statement of Comprehensive Income



Consolidating Statements of Comprehensive Income
For the Three Months Ended March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations			Piedmont (Consolidated)
Net income	$	57,830	$	56,934	$	68,665	$	(125,599	)	$	57,830
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,517		1,517		—		(1,517		)	1,517
Plus: Reclassification of net loss included in net income	1,052		1,052		—		(1,052		)	1,052
Other comprehensive income	2,569		2,569		—		(2,569		)	2,569

Comprehensive income	$	60,399	$	59,503	$	68,665	$	(128,168	)	$	60,399

Condensed Consolidated Statements of Cash Flows



Condensed Consolidating Statements of Cash Flows
For the three months ended March 31, 2018
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations			Piedmont (Consolidated)
Net Cash Provided by/(Used in) Operating Activities	$	58,739		$	56,468		$	43,698		$	(125,595	)	$	33,310

Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	—			(2,004		)	(38,903		)	—			(40,907		)
Intercompany note receivable	—			88,000			—			(88,000		)	—
Net sales proceeds from wholly-owned properties	—			32,086			382,992			—			415,078
Note receivable issuance	—			—			(3,200		)	—			(3,200		)
Deferred lease costs paid	—			(5		)	(2,591		)	—			(2,596		)
Distributions from subsidiaries	305,266			62,437			—			(367,703		)	—
Net cash provided by investing activities	305,266			180,514			338,298			(455,703		)	368,375
Cash Flows from Financing Activities:
Debt issuance costs paid	—			(101		)	—			—			(101		)
Proceeds from debt	—			716,225			—			—			716,225
Repayments of debt	—			(754,000		)	(359		)	—			(754,359		)
Intercompany note payable	—			—			(88,000		)	88,000			—
Value of shares withheld to pay tax obligations related to employee stock compensation	(737		)	—			—			—			(737		)
Repurchases of common stock as part of announced plan	(233,164		)	—			—			—			(233,164		)
Distributions	(130,104		)	(198,964		)	(294,341		)	493,298			(130,111		)
Net cash used in financing activities	(364,005		)	(236,840		)	(382,700		)	581,298			(402,247		)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—			142			(704		)	—			(562		)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150			3,906			4,699			—			8,755
Cash, cash equivalents, and restricted cash and escrows, end of period	$	150		$	4,048		$	3,995		$	—		$	8,193



Condensed Consolidating Statements of Cash Flows
For the three months ended March 31, 2017
(in thousands)	Piedmont (Parent) (Guarantor)			Piedmont OP (the Issuer)			Non-Guarantors			Eliminations		Piedmont (Consolidated)
Net Cash Provided by/(Used in) Operating Activities	$	998		$	(5,748	)	$	55,044		$	—	$	50,294

Cash Flows from Investing Activities:
Investment in real estate assets, consolidated joint venture, and real estate related intangibles, net of accruals	—			(407		)	(27,796		)	—		(28,203		)
Investments in unconsolidated joint ventures	—			(284		)	—			—		(284		)
Net sales proceeds from wholly-owned properties	—			(58		)	(6		)	—		(64		)
Deferred lease costs paid	—			(305		)	(3,965		)	—		(4,270		)
Net cash provided by/(used in) investing activities	—			(1,054		)	(31,767		)	—		(32,821		)
Cash Flows from Financing Activities:
Debt issuance costs paid	—			(63		)	—			—		(63		)
Proceeds from debt	—			100,000			—			—		100,000
Repayments of debt	—			(55,000		)	(345		)	—		(55,345		)
Value of shares withheld to pay tax obligations related to employee stock compensation	(1,128		)	—			—			—		(1,128		)
(Distributions to)/repayments from affiliates	61,210			(38,103		)	(23,107		)	—		—
Dividends paid and discount on dividend reinvestments	(61,080		)	—			—			—		(61,080		)
Net cash provided by/(used in) financing activities	(998		)	6,834			(23,452		)	—		(17,616		)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—			32			(175		)	—		(143		)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150			3,693			4,361			—		8,204
Cash, cash equivalents, and restricted cash and escrows, end of period	$	150		$	3,725		$	4,186		$	—	$	8,061

Organization (Details) ft² in Millions	3 Months Ended
Organization (Details) ft² in Millions	Mar. 31, 2018 ft² segment asset property subsidiary market
Real Estate Properties [Line Items]
Number of wholly-owned subsidiaries \| subsidiary	2
Percentage ownership by sole general partner	99.90%
Percentage ownership by sole limited partner	0.10%
Number of redevelopment assets \| asset	1
Percentage of annualized lease revenue	90.00%
Number of operating segments \| segment	1
U.S.
Real Estate Properties [Line Items]
Number of major U.S. office markets \| market	8
In Service Office Properties
Real Estate Properties [Line Items]
Number of real estate properties \| property	53
Square footage of real estate property \| ft²	16
Percentage leased	91.30%

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Concentration Risk [Line Items]
Reduction in tax liability	$ 200
Reclassification out of rental income	(101,454)	$ (118,039)
Reclassification into other property related income	5,143	5,062
Reclassification out of general and administrative expenses	(6,552)	(8,150)
Reclassification into property operating costs	51,859	55,830
Cumulative effect of accounting change (adoption of ASU 2016-01)			$ 0
Accounting Standards Update 2016-01
Concentration Risk [Line Items]
Cumulative effect of accounting change (adoption of ASU 2016-01)	(100)
Restatement Adjustment [Member]
Concentration Risk [Line Items]
Reclassification out of general and administrative expenses		400
Reclassification into property operating costs		$ 400
Difference between Revenue Guidance in Effect before and after Topic 606 \| Accounting Standards Update 2014-09
Concentration Risk [Line Items]
Reclassification out of rental income	5,100
Reclassification into other property related income	$ 5,100

Summary of Significant Accounting Policies - Revenue Recognition Amendments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accounting Policies [Abstract]
Rental income	$ 101,454	$ 118,039
Tenant reimbursements	22,994	24,837
Property management fee revenue	309	525
Other property related income	5,143	5,062
Total revenues	$ 129,900	$ 148,463

Acquisitions (Details) - 501 West Church Street $ in Millions	3 Months Ended
	Mar. 31, 2018 USD ($) ft²
Business Acquisition [Line Items]
Ownership Percentage Acquired	100.00%
Rentable Square Feet \| ft²	182,461
Percentage Leased as of Acquisition	100.00%
Net Contractual Purchase Price (in millions) \| $	$ 28.0

Debt (Details)	1 Months Ended	3 Months Ended
Debt (Details)	Jan. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) period	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Debt Instrument [Line Items]
Weighted average rate		3.69%
Amount Outstanding		$ 1,689,644,000		$ 1,726,927,000
Net premium, discounts, and unamortized debt issuance costs		(8,661,000)		(7,689,000)
Loss on extinguishment of debt	$ 400,000	1,680,000	$ 0
Interest rate swaps
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements		450,000,000
$250 Million Unsecured 2018 Term Loan \| Interest rate swaps
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements		$ 150,000,000
$250 Million Unsecured 2018 Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Seven-Year Interest Rate Swap Agreement \| Interest rate swaps
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements		$ 100,000,000
Two-Year Interest Rate Swap Agreement \| Interest rate swaps
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements		$ 50,000,000
Secured Debt
Debt Instrument [Line Items]
Weighted average rate		3.81%
Amount Outstanding		$ 191,305,000		191,616,000
Net premium, discounts, and unamortized debt issuance costs		871,000		946,000
Secured Debt \| $35 Million Fixed-Rate Loan
Debt Instrument [Line Items]
Face amount of debt instrument		$ 35,000,000.0
Stated Rate		5.55%
Effective interest rate		3.75%
Amount Outstanding		$ 30,434,000		30,670,000
Secured Debt \| $160 Million Fixed Rate Loan
Debt Instrument [Line Items]
Face amount of debt instrument		$ 160,000,000
Stated Rate		3.48%
Effective interest rate		3.58%
Amount Outstanding		$ 160,000,000		160,000,000
Unsecured Debt
Debt Instrument [Line Items]
Weighted average rate		3.67%
Amount Outstanding		$ 1,498,339,000		1,535,311,000
Net premium, discounts, and unamortized debt issuance costs		(8,661,000)		(7,689,000)
Unsecured Debt \| $170 Million Unsecured 2015 Term Loan
Debt Instrument [Line Items]
Face amount of debt instrument		$ 170,000,000
Effective interest rate		2.54%
Amount Outstanding		$ 0		170,000,000
Amount fully repaid		$ 170,000,000
Unsecured Debt \| $170 Million Unsecured 2015 Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.125%
Unsecured Debt \| $300 Million Unsecured 2013 Term Loan
Debt Instrument [Line Items]
Face amount of debt instrument		$ 300,000,000
Amount Outstanding		0		300,000,000
Amount fully repaid		$ 300,000,000
Unsecured Debt \| $300 Million Unsecured 2013 Term Loan \| Interest rate swaps
Debt Instrument [Line Items]
Effective interest rate		2.78%
Unsecured Debt \| $300 Million Unsecured 2013 Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.20%
Unsecured Debt \| $500 Million Unsecured 2015 Line of Credit \| Line of Credit
Debt Instrument [Line Items]
Face amount of debt instrument		$ 500,000,000
Effective interest rate		2.87%
Amount Outstanding		$ 207,000,000		23,000,000
Maximum extension period		1 year
Number of extension periods \| period		2
Extension period		6 months
Amount of line of credit		$ 500,000,000
Unsecured Debt \| $500 Million Unsecured 2015 Line of Credit \| Line of Credit \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.00%
Unsecured Debt \| $300 Million Unsecured 2011 Term Loan
Debt Instrument [Line Items]
Face amount of debt instrument		$ 300,000,000
Amount Outstanding		$ 300,000,000		300,000,000
Unsecured Debt \| $300 Million Unsecured 2011 Term Loan \| Interest rate swaps
Debt Instrument [Line Items]
Effective interest rate		3.35%
Unsecured Debt \| $300 Million Unsecured 2011 Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.15%
Unsecured Debt \| $350 Million Senior Notes
Debt Instrument [Line Items]
Face amount of debt instrument		$ 350,000,000
Stated Rate		3.40%
Effective interest rate		3.43%
Amount Outstanding		$ 350,000,000		350,000,000
Unsecured Debt \| $400 Million Senior Notes
Debt Instrument [Line Items]
Face amount of debt instrument		$ 400,000,000
Stated Rate		4.45%
Effective interest rate		4.10%
Amount Outstanding		$ 400,000,000		400,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Face amount of debt instrument		$ 250,000,000
Effective interest rate		3.86%
Amount Outstanding		$ 250,000,000		$ 0
Notional amount of interest rate swap agreements		$ 150,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate		1.60%
Through March 29, 2020 \| Unsecured Debt \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Interest rate on derivative instrument		4.11%
From March 30, 2020 through March 31, 2025 \| Unsecured Debt \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Interest rate on derivative instrument		4.21%

Debt (Narrative) (Details) - USD ($)	3 Months Ended
Debt (Narrative) (Details) - USD ($)	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Document period end date	Mar. 31, 2018
Amount outstanding	$ 1,689,644,000		$ 1,726,927,000
Interest paid	15,900,000	$ 19,200,000
Interest costs capitalized	100,000	$ 100,000
Unsecured Debt
Debt Instrument [Line Items]
Amount outstanding	1,498,339,000		1,535,311,000
$300 Million Unsecured 2013 Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Repayment of long-term debt	300,000,000
Amount outstanding	0		300,000,000
Face amount of debt instrument	300,000,000
$170 Million Unsecured 2015 Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Repayment of long-term debt	170,000,000
Amount outstanding	0		170,000,000
Face amount of debt instrument	170,000,000
$250 Million Unsecured 2018 Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Amount outstanding	$ 250,000,000		0
Debt instrument term	7 years
Face amount of debt instrument	$ 250,000,000
Unencumbered interest coverage ratio	1.75
Unencumbered leverage ratio	1.60
Fixed charge coverage ratio	1.50
Maximum leverage ratio	0.60
Maximum secured debt ratio	0.40
Notional amount of interest rate swap agreements	$ 150,000,000
Line of Credit \| $500 Million Unsecured 2015 Line of Credit \| Unsecured Debt
Debt Instrument [Line Items]
Net borrowings on lines of credit	184,000,000
Amount of line of credit	500,000,000
Amount outstanding	207,000,000		$ 23,000,000
Face amount of debt instrument	$ 500,000,000
Federal Funds Rate \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
London Interbank Offered Rate (LIBOR) \| $300 Million Unsecured 2013 Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.20%
London Interbank Offered Rate (LIBOR) \| $170 Million Unsecured 2015 Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.125%
London Interbank Offered Rate (LIBOR) \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Current basis spread on variable rate	1.60%
London Interbank Offered Rate (LIBOR) \| $250 Million Unsecured 2018 Term Loan \| Unsecured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.60%
London Interbank Offered Rate (LIBOR) \| Line of Credit \| $500 Million Unsecured 2015 Line of Credit \| Unsecured Debt
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Minimum \| London Interbank Offered Rate (LIBOR) \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	1.45%
Maximum \| London Interbank Offered Rate (LIBOR) \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Basis spread on variable rate	2.40%
Interest rate swaps
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	$ 450,000,000
Interest rate swaps \| $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	$ 150,000,000

Variable Interest Entities (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Eye Street 1201 N.W. Associates LLC
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	98.60%
Net Carrying Amount	$ 83.7	$ 81.1
Percent of cash flow entitled to entity	100.00%
Eye Street 1225 N.W. Associates LLC
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	98.10%
Net Carrying Amount	$ 64.3	65.2
Percent of cash flow entitled to entity	100.00%
Piedmont 500 W. Monroe Fee LLC
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	100.00%
Net Carrying Amount	$ 260.8	$ 263.2
Percent of cash flow entitled to entity	100.00%

Derivative Instruments (Details)		1 Months Ended	3 Months Ended		12 Months Ended
Derivative Instruments (Details)	Jan. 04, 2018 USD ($)	Jan. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) contract	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Derivative [Line Items]
Cash received upon settlement of interest rate swaps			$ 807,000		$ 0
Maximum period of extension term			84 months
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Gross derivative assets			$ 725,000		688,000
Gross derivative liabilities			(222,000)		(1,478,000)
Net derivative asset/(liability)			503,000		$ (790,000)
Total amount of Interest Expense presented in the consolidated statements of income			13,758,000	$ 18,057,000
Loss on extinguishment of debt		$ (400,000)	(1,680,000)	0
Loss to be reclassified from accumulated other comprehensive loss to interest expense over next twelve months			(1,800,000)
Loss related to hedge ineffectiveness and terminations of cash flow hedges			0	0
Interest rate swaps
Derivative [Line Items]
Total Notional Amount (in millions)			450,000,000
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Total amount of Interest Expense presented in the consolidated statements of income			13,758,000	18,057,000
Interest rate swaps \| Interest Expense
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Amount of gain recognized in OCI			1,517,000	1,044,000
Amount of previously recorded gain/(loss) reclassified from OCI into Interest Expense			206,000	(1,306,000)
Interest rate swaps \| Gain (Loss) On Extinguishment Of Debt [Member]
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Amount of previously recorded gain/(loss) reclassified from OCI into Interest Expense			(1,258,000)	$ 0
Credit Risk Contract
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Assets needed for immediate settlement, aggregate fair value			100,000
$250 Million Unsecured 2018 Term Loan \| Interest rate swaps
Derivative [Line Items]
Total Notional Amount (in millions)			150,000,000
Unsecured Debt \| $300 Million Unsecured 2013 Term Loan
Derivative [Line Items]
Repayment of long-term debt			300,000,000
Cash received upon settlement of interest rate swaps	$ 800,000
Face amount of debt instrument			300,000,000
Unsecured Debt \| $300 Million Unsecured 2013 Term Loan \| Interest rate swaps
Derivative [Line Items]
Loss on termination	$ 1,300,000		(100,000)
Unsecured Debt \| $300 Million Unsecured 2011 Term Loan
Derivative [Line Items]
Face amount of debt instrument			$ 300,000,000
Unsecured Debt \| $300 Million Unsecured 2011 Term Loan \| Interest Rate Swaps 1 through 3
Derivative [Line Items]
Number of Swap Agreements \| contract			3
Total Notional Amount (in millions)			$ 300,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan
Derivative [Line Items]
Face amount of debt instrument			250,000,000
Hedged portion of long-term debt			150,000,000
Total Notional Amount (in millions)			$ 150,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan \| Interest Rate Swaps 4 and 5
Derivative [Line Items]
Number of Swap Agreements \| contract			2
Total Notional Amount (in millions)			$ 100,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan Maturing 2020 \| Interest Rate Swap 6
Derivative [Line Items]
Number of Swap Agreements \| contract			1
Total Notional Amount (in millions)			$ 50,000,000

Fair Value Measurement of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	$ 725	$ 688
Interest rate swaps	222	1,478
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	6,729	7,382
Restricted cash and escrows	1,464	1,373
Accounts payable and accrued expenses	10,222	126,429
Debt, net	1,689,644	1,726,927
Interest rate swaps \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	725	688
Interest rate swaps	222	1,478
Tenant receivables, net \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	12,040	12,139
Notes receivable \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	3,200	0
Level 1 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	6,729	7,382
Restricted cash and escrows	1,464	1,373
Accounts payable and accrued expenses	10,222	126,429
Level 1 \| Tenant receivables, net \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	12,040	12,139
Level 1 \| Notes receivable \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	3,200	0
Level 2 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, net	1,701,284	1,759,905
Level 2 \| Interest rate swaps \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	725	688
Interest rate swaps	$ 222	$ 1,478

Commitments and Contingencies (Details)	3 Months Ended
Commitments and Contingencies (Details)	Mar. 31, 2018 USD ($) category	Mar. 31, 2017 USD ($)
Loss Contingencies [Line Items]
Number of tenant and building improvement categories \| category	2
Collectibility of Tenant Reimbursements
Loss Contingencies [Line Items]
Reductions in reimbursement revenues	$ 423,000	$ 200,000
Non-Incremental Capital Expenditures
Loss Contingencies [Line Items]
Period for commitments for funding non-incremental capital expenditures	5 years
Potential obligations for tenant improvements	$ 34,700,000
Non-Incremental Capital Expenditures \| Maximum
Loss Contingencies [Line Items]
Period for commitments for funding non-incremental capital expenditures	3 years
Incremental Capital Expenditures
Loss Contingencies [Line Items]
Potential obligations for tenant improvements	$ 12,500,000

Property Dispositions and Assets Held for Sale (Property Dispositions) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) property extension	Mar. 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold \| property	14
Document Period End Date	Mar. 31, 2018
Gain/(loss) on sale of real estate assets, net	$ 45,209	$ (53)
Disposal Group, Disposed of by Sale, Not Discontinued Operations \| 2017 Disposition Portfolio
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net sales proceeds	415,078
Secured Promissory Note \| Secured Debt
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Face amount of debt instrument	$ 3,200
Interest rate	7.00%
Number of maturity extension periods \| extension	2
Maturity extension period	6 months

Property Dispositions and Assets Held for Sale (Assets Held-for-Sale) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Document period end date	Mar. 31, 2018
Total other assets held for sale, net	$ 0	$ 47,131
Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total real estate assets held for sale, net	0	332,410
Straight-line rent receivables	0	25,975
Prepaid expenses and other assets	0	328
Deferred lease costs, less accumulated amortization of $0 and $16,549 as of March 31, 2018 and December 31, 2017, respectively	0	20,828
Total other assets held for sale, net	0	47,131
Intangible lease liabilities, less accumulated amortization of $0 and $935 as of March 31, 2018 and December 31, 2017, respectively	0	380
Accumulated amortization on deferred lease costs	0	16,549
Accumulated amortization on Intangible lease liabilities	0	935
Disposal Group, Held-for-sale, Not Discontinued Operations \| Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	0	74,498
Disposal Group, Held-for-sale, Not Discontinued Operations \| Building and building improvements
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	0	255,634
Accumulated depreciation (building improvements)	0	169,116
Disposal Group, Held-for-sale, Not Discontinued Operations \| Construction in progress
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	$ 0	$ 2,278
Secured Debt \| Secured Promissory Note
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Basis spread on variable rate	0.25%

Stock Based Compensation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense related to stock awards	$ 1.0	$ 3.2
Total shares issued to employees, directors, and officers (in shares)	148,093
Unrecognized compensation cost related to nonvested	$ 2.6
Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to nonvested, weighted-average vesting period	1 year
Stock Awards \| Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year

Stock Based Compensation (Rollforward of Stock Awards) (Details)	3 Months Ended
	Mar. 31, 2018 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested and Potential Stock Awards, End of period (in shares)	657,502
Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested and Potential Stock Awards, Beginning of period (in shares)	868,437
Unvested and Potential Stock Awards, End of period (in shares)	657,502
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Unvested and Potential Stock Awards, Weighted-Average Grant Date Fair Value, Beginning of period (in dollars per share) \| $ / shares	$ 21.69
Unvested and Potential Stock Awards, Weighted-Average Grant Date Fair Value, End of period (in dollars per share) \| $ / shares	$ 22.85
Deferred Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Performance Stock Awards and Deferred Stock Awards Vested (in shares)	(38,883)
Deferred Stock Awards Forfeited (in shares)	(5,064)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Performance Stock Awards and Deferred Stock Awards Vested, Weighted-Average Grant Date Fair Value (in dollars per share) \| $ / shares	$ 18.60
Deferred Stock Awards Forfeited, Weighted-Average Grant Date Fair Value (in dollars per share) \| $ / shares	$ 20.19
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Decrease in Estimated Potential Share Award, net of forfeitures (in shares)	(17,176)
Performance Stock Awards and Deferred Stock Awards Vested (in shares)	(149,812)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Decrease in Estimated Potential Share Award, net of forfeitures, Weighted-Average Grant Date Fair Value (in dollars per share) \| $ / shares	$ 24.70
Performance Stock Awards and Deferred Stock Awards Vested, Weighted-Average Grant Date Fair Value (in dollars per share) \| $ / shares	$ 18.42

Stock Based Compensation (Additional Information Regarding Stock Award Activity) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Deferred Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total Grant Date Fair Value of Deferred Stock Vested During the Period	$ 723	$ 290
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Liability Awards Paid During the Period	$ 2,947	$ 2,606

Stock Based Compensation (Outstanding Employee Stock Awards) (Details) - $ / shares	May 18, 2017	May 24, 2016	May 01, 2015	Jan. 03, 2014	Mar. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Shares (in shares)					657,502
Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value (in dollars per share)					$ 22.85	$ 21.69
Unvested Shares (in shares)					657,502	868,437
Deferred Stock Awards \| Deferred Stock Award, Granted January 3, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)				65,252
Grant Date Fair Value (in dollars per share)				$ 16.45
Unvested Shares (in shares)					16,416
Deferred Stock Awards \| Deferred Stock Award, Granted January 3, 2014 \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards \| Deferred Stock Award, Granted January 3, 2014 \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards \| Deferred Stock Award, Granted January 3, 2014 \| Share-based Compensation Award, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards \| Deferred Stock Award, Granted January 3, 2014 \| Share-based Compensation Award, Tranche Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards \| Deferred Stock Award, Granted January 3, 2014 \| Share-based Compensation Award, Tranche Five
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage				20.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 1, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)			214,891
Grant Date Fair Value (in dollars per share)			$ 17.59
Unvested Shares (in shares)					61,923
Deferred Stock Awards \| Deferred Stock Award, Granted May 1, 2015 \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 1, 2015 \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 1, 2015 \| Share-based Compensation Award, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 1, 2015 \| Share-based Compensation Award, Tranche Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 24, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)		230,309
Grant Date Fair Value (in dollars per share)		$ 19.91
Unvested Shares (in shares)					122,470
Deferred Stock Awards \| Deferred Stock Award, Granted May 24, 2016 \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 24, 2016 \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 24, 2016 \| Share-based Compensation Award, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 24, 2016 \| Share-based Compensation Award, Tranche Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award - Board of Directors, Granted May 18, 2017 \| Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)	26,187
Grant Date Fair Value (in dollars per share)	$ 21.38
Unvested Shares (in shares)					26,187
Deferred Stock Awards \| Deferred Stock Award - Board of Directors, Granted May 18, 2017 \| Share-based Compensation Award, Tranche One \| Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	100.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 18, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)	242,742
Grant Date Fair Value (in dollars per share)	$ 21.38
Unvested Shares (in shares)					187,000
Deferred Stock Awards \| Deferred Stock Award, Granted May 18, 2017 \| Share-based Compensation Award, Tranche One
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 18, 2017 \| Share-based Compensation Award, Tranche Two
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 18, 2017 \| Share-based Compensation Award, Tranche Three
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 18, 2017 \| Share-based Compensation Award, Tranche Four
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage	25.00%
Performance Share Awards \| Performance Share Program Award, Granted May 24, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)		0
Grant Date Fair Value (in dollars per share)		$ 23.02
Unvested Shares (in shares)					100,171
Performance Share Awards \| Performance Share Program Award, Granted May 18, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)	0
Grant Date Fair Value (in dollars per share)	$ 30.45
Unvested Shares (in shares)					143,335

Supplemental Disclosures for the Statement of Consolidated Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Accrued capital expenditures and deferred lease costs	$ 6,222	$ 12,478
Change in accrued dividends and discount on dividend reinvestments	101,800	30,532
Change in accrued share repurchases as part of an announced plan	(1,276)	0
Accrued deferred financing costs	44	0
Cash and cash equivalents	6,729		$ 7,382
Restricted cash and escrows:
Real estate tax and escrowed cash	927		833
Security and utility deposit escrows	537		540
Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows	$ 8,193	$ 8,061	$ 8,755	$ 8,204

Earnings Per Share (Details) - shares	3 Months Ended
Earnings Per Share (Details) - shares	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Weighted-average common shares outstanding – basic (in shares)	135,876,652	145,286,930
Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards (in shares)	306,000	546,000
Weighted-average common shares outstanding – diluted (in shares)	136,182,728	145,833,488
Common stock, shares issued (in shares)	130,024,873		142,358,940	145,320,000
Common stock, shares outstanding (in shares)	130,024,873	145,320,000	142,358,940

Guarantor and Non-Guarantor Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets:
Land	$ 547,602	$ 544,794
Buildings and improvements, less accumulated depreciation	2,424,570	2,418,023
Intangible lease assets, less accumulated amortization	75,275	77,805
Construction in progress	15,226	11,710
Real estate assets held for sale, net	0	332,410
Total real estate assets	3,062,673	3,384,742
Cash and cash equivalents	6,729	7,382
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	179,585	175,309
Advances to affiliates		0
Investment in subsidiaries	0	0
Notes receivable	3,200	0
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	27,217	24,578
Goodwill	98,918	98,918
Deferred lease costs, net	257,368	261,907
Other assets held for sale, net	0	47,131
Total assets	3,635,690	3,999,967
Liabilities:
Debt, net	1,689,644	1,726,927
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	83,786	216,653
Advances from affiliates		0
Deferred income	29,751	29,582
Intangible lease liabilities, net	42,699	38,458
Interest rate swaps	222	1,478
Liabilities held for sale, net	0	380
Total liabilities	1,846,102	2,013,478
Equity:
Total stockholders’ equity	1,789,588	1,986,489	$ 2,097,703
Total liabilities and stockholders’ equity	3,635,690	3,999,967
Eliminations
Assets:
Land	0	0
Buildings and improvements, less accumulated depreciation	(300)	(300)
Intangible lease assets, less accumulated amortization	0	0
Construction in progress	0	0
Real estate assets held for sale, net		0
Total real estate assets	(300)	(300)
Cash and cash equivalents	0	0
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	0	0
Advances to affiliates		(7,971,908)
Investment in subsidiaries	(4,598,653)	(3,437,471)
Notes receivable	(145,310)	(233,310)
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	(14)	(740)
Goodwill	0	0
Deferred lease costs, net	0	0
Other assets held for sale, net		0
Total assets	(4,744,277)	(11,643,729)
Liabilities:
Debt, net	(145,310)	(233,310)
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	(14)	(740)
Advances from affiliates		(8,070,163)
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps	0	0
Liabilities held for sale, net		0
Total liabilities	(145,324)	(8,304,213)
Equity:
Total stockholders’ equity	(4,598,953)	(3,339,516)
Total liabilities and stockholders’ equity	(4,744,277)	(11,643,729)
Piedmont (Parent) (Guarantor)
Assets:
Land	0	0
Buildings and improvements, less accumulated depreciation	0	0
Intangible lease assets, less accumulated amortization	0	0
Construction in progress	0	0
Real estate assets held for sale, net		0
Total real estate assets	0	0
Cash and cash equivalents	150	150
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	0	0
Advances to affiliates		1,674,276
Investment in subsidiaries	1,790,277	3,437,299
Notes receivable	0	0
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	116	2
Goodwill	0	0
Deferred lease costs, net	0	0
Other assets held for sale, net		0
Total assets	1,790,543	5,111,727
Liabilities:
Debt, net	0	0
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	955	104,028
Advances from affiliates		5,277,957
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps	0	0
Liabilities held for sale, net		0
Total liabilities	955	5,381,985
Equity:
Total stockholders’ equity	1,789,588	(270,258)
Total liabilities and stockholders’ equity	1,790,543	5,111,727
Piedmont OP (the Issuer)
Assets:
Land	36,094	36,094
Buildings and improvements, less accumulated depreciation	178,181	180,886
Intangible lease assets, less accumulated amortization	45	181
Construction in progress	390	85
Real estate assets held for sale, net		32,815
Total real estate assets	214,710	250,061
Cash and cash equivalents	4,017	3,890
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	16,870	16,891
Advances to affiliates		6,297,632
Investment in subsidiaries	2,808,205	0
Notes receivable	810	88,810
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	8,864	5,094
Goodwill	98,918	98,918
Deferred lease costs, net	15,976	16,611
Other assets held for sale, net		2,266
Total assets	3,168,370	6,780,173
Liabilities:
Debt, net	1,498,271	1,535,239
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	14,028	20,279
Advances from affiliates		941,494
Deferred income	2,757	3,631
Intangible lease liabilities, net	0	0
Interest rate swaps	222	1,478
Liabilities held for sale, net		0
Total liabilities	1,515,278	2,502,121
Equity:
Total stockholders’ equity	1,653,092	4,278,052
Total liabilities and stockholders’ equity	3,168,370	6,780,173
Non-Guarantors
Assets:
Land	511,508	508,700
Buildings and improvements, less accumulated depreciation	2,246,689	2,237,437
Intangible lease assets, less accumulated amortization	75,230	77,624
Construction in progress	14,836	11,625
Real estate assets held for sale, net		299,595
Total real estate assets	2,848,263	3,134,981
Cash and cash equivalents	2,562	3,342
Tenant and straight-line rent receivables, net and amounts due from unconsolidated joint ventures	162,715	158,418
Advances to affiliates		0
Investment in subsidiaries	171	172
Notes receivable	147,700	144,500
Prepaid expenses, restricted cash, escrows, interest rate swaps and other assets	18,251	20,222
Goodwill	0	0
Deferred lease costs, net	241,392	245,296
Other assets held for sale, net		44,865
Total assets	3,421,054	3,751,796
Liabilities:
Debt, net	336,683	424,998
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	68,817	93,086
Advances from affiliates		1,850,712
Deferred income	26,994	25,951
Intangible lease liabilities, net	42,699	38,458
Interest rate swaps	0	0
Liabilities held for sale, net		380
Total liabilities	475,193	2,433,585
Equity:
Total stockholders’ equity	2,945,861	1,318,211
Total liabilities and stockholders’ equity	$ 3,421,054	$ 3,751,796

Guarantor and Non-Guarantor Financial Information (Condensed Consolidating Statements of Income) (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2018	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Revenues:
Rental income		$ 101,454	$ 118,039
Tenant reimbursements		22,994	24,837
Property management fee revenue		309	525
Other property related income		5,143	5,062
Total revenues		129,900	148,463
Expenses:
Property operating costs		51,859	55,830
Depreciation		27,145	30,768
Amortization		16,733	20,415
General and administrative		6,552	8,150
Operating expenses		102,289	115,163
Real estate operating income		27,611	33,300
Other income (expense):
Interest expense		(13,758)	(18,057)
Other income/(expense)		446	(100)
Equity in income of unconsolidated joint ventures		0	11
Loss on extinguishment of debt	$ (400)	(1,680)	0
Gain on sale of real estate assets		45,209	(53)
Other income (expense)		30,217
Income/(loss) before consolidated subsidiaries		57,828
Income/(loss) from subsidiaries		0
Net income/(loss)		57,828	15,101
Plus: Net loss applicable to noncontrolling interest		2	3	$ 15
Net income applicable to Piedmont		57,830	15,104	$ 133,564
Eliminations
Revenues:
Rental income		(432)	(458)
Tenant reimbursements		(84)	(104)
Property management fee revenue		(3,872)	(4,111)
Other property related income		0	0
Total revenues		(4,388)	(4,673)
Expenses:
Property operating costs		(4,388)	(4,673)
Depreciation		0	0
Amortization		0	0
General and administrative		0	0
Operating expenses		(4,388)	(4,673)
Real estate operating income		0	0
Other income (expense):
Interest expense		1,962	3,638
Other income/(expense)		(1,962)	(3,638)
Equity in income of unconsolidated joint ventures			0
Loss on extinguishment of debt		0
Gain on sale of real estate assets		0	0
Other income (expense)		0
Income/(loss) before consolidated subsidiaries		0
Income/(loss) from subsidiaries		(125,599)
Net income/(loss)		(125,599)	0
Plus: Net loss applicable to noncontrolling interest		0	0
Net income applicable to Piedmont		(125,599)	0
Piedmont (Parent) (Guarantor)
Revenues:
Rental income		0	0
Tenant reimbursements		0	0
Property management fee revenue		0	0
Other property related income		0	0
Total revenues		0	0
Expenses:
Property operating costs		0	0
Depreciation		0	0
Amortization		0	0
General and administrative		100	103
Operating expenses		100	103
Real estate operating income		(100)	(103)
Other income (expense):
Interest expense		0	0
Other income/(expense)		0	0
Equity in income of unconsolidated joint ventures			0
Loss on extinguishment of debt		0
Gain on sale of real estate assets		0	0
Other income (expense)		0
Income/(loss) before consolidated subsidiaries		(100)
Income/(loss) from subsidiaries		57,930
Net income/(loss)		57,830	(103)
Plus: Net loss applicable to noncontrolling interest		0	0
Net income applicable to Piedmont		57,830	(103)
Piedmont OP (the Issuer)
Revenues:
Rental income		8,815	11,388
Tenant reimbursements		2,646	3,005
Property management fee revenue		0	0
Other property related income		27	32
Total revenues		11,488	14,425
Expenses:
Property operating costs		4,713	5,802
Depreciation		2,865	3,463
Amortization		611	856
General and administrative		1,887	1,702
Operating expenses		10,076	11,823
Real estate operating income		1,412	2,602
Other income (expense):
Interest expense		(12,021)	(14,444)
Other income/(expense)		124	2,229
Equity in income of unconsolidated joint ventures			11
Loss on extinguishment of debt		(1,680)
Gain on sale of real estate assets		1,430	(61)
Other income (expense)		(12,147)
Income/(loss) before consolidated subsidiaries		(10,735)
Income/(loss) from subsidiaries		67,669
Net income/(loss)		56,934	(9,663)
Plus: Net loss applicable to noncontrolling interest		0	0
Net income applicable to Piedmont		56,934	(9,663)
Non-Guarantors
Revenues:
Rental income		93,071	107,109
Tenant reimbursements		20,432	21,936
Property management fee revenue		4,181	4,636
Other property related income		5,116	5,030
Total revenues		122,800	138,711
Expenses:
Property operating costs		51,534	54,701
Depreciation		24,280	27,305
Amortization		16,122	19,559
General and administrative		4,565	6,345
Operating expenses		96,501	107,910
Real estate operating income		26,299	30,801
Other income (expense):
Interest expense		(3,699)	(7,251)
Other income/(expense)		2,284	1,309
Equity in income of unconsolidated joint ventures			0
Loss on extinguishment of debt		0
Gain on sale of real estate assets		43,779	8
Other income (expense)		42,364
Income/(loss) before consolidated subsidiaries		68,663
Income/(loss) from subsidiaries		0
Net income/(loss)		68,663	24,867
Plus: Net loss applicable to noncontrolling interest		2	3
Net income applicable to Piedmont		$ 68,665	$ 24,870

Guarantor and Non-Guarantor Financial Information (Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	$ 57,830	$ 15,104	$ 133,564
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,517	1,044
Plus: Reclassification of net loss included in net income	1,052	1,306
Other comprehensive income	2,569	2,362	$ 6,060
Comprehensive income	60,399	17,466
Piedmont (Parent) (Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	57,830	(103)
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,517
Plus: Reclassification of net loss included in net income	1,052
Other comprehensive income	2,569
Comprehensive income	60,399
Piedmont OP (the Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	56,934	(9,663)
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,517
Plus: Reclassification of net loss included in net income	1,052
Other comprehensive income	2,569
Comprehensive income	59,503
Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	68,665	24,870
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	0
Plus: Reclassification of net loss included in net income	0
Other comprehensive income	0
Comprehensive income	68,665
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	(125,599)	$ 0
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	(1,517)
Plus: Reclassification of net loss included in net income	(1,052)
Other comprehensive income	(2,569)
Comprehensive income	$ (128,168)

Guarantor and Non-Guarantor Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Payments for (Proceeds from) Intercompany Distributions		$ 0
Net Cash Provided by/(Used in) Operating Activities	$ 33,310	50,294
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(40,907)	(28,203)
Intercompany note receivable	0
Net sales proceeds from wholly-owned properties	415,078	(64)
Note receivable issuance	(3,200)	0
Deferred lease costs paid	(2,596)	(4,270)
Distributions from subsidiaries	0
Investments in unconsolidated joint ventures		(284)
Net cash provided by/(used in) investing activities	368,375	(32,821)
Cash Flows from Financing Activities:
Debt issuance costs paid	(101)	(63)
Proceeds from debt	716,225	100,000
Repayments of debt	(754,359)	(55,345)
Intercompany note payable	0
Value of shares withheld to pay tax obligations related to employee stock compensation	(737)	(1,128)
Repurchases of common stock as part of announced plan	(233,164)	0
Dividends paid and discount on dividend reinvestments	(130,111)	(61,080)
Net cash used in financing activities	(402,247)	(17,616)
Net decrease in cash, cash equivalents, and restricted cash and escrows	(562)	(143)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	8,755	8,204
Cash, cash equivalents, and restricted cash and escrows, end of period	8,193	8,061
Eliminations
Condensed Financial Statements, Captions [Line Items]
Payments for (Proceeds from) Intercompany Distributions		0
Net Cash Provided by/(Used in) Operating Activities	(125,595)	0
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Intercompany note receivable	(88,000)
Net sales proceeds from wholly-owned properties	0	0
Note receivable issuance	0
Deferred lease costs paid	0	0
Distributions from subsidiaries	(367,703)
Investments in unconsolidated joint ventures		0
Net cash provided by/(used in) investing activities	(455,703)	0
Cash Flows from Financing Activities:
Debt issuance costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Intercompany note payable	88,000
Value of shares withheld to pay tax obligations related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0
Dividends paid and discount on dividend reinvestments	493,298	0
Net cash used in financing activities	581,298	0
Net decrease in cash, cash equivalents, and restricted cash and escrows	0	0
Cash, cash equivalents, and restricted cash and escrows, beginning of period	0	0
Cash, cash equivalents, and restricted cash and escrows, end of period	0	0
Piedmont (Parent) (Guarantor)
Condensed Financial Statements, Captions [Line Items]
Payments for (Proceeds from) Intercompany Distributions		(61,210)
Net Cash Provided by/(Used in) Operating Activities	58,739	998
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Intercompany note receivable	0
Net sales proceeds from wholly-owned properties	0	0
Note receivable issuance	0
Deferred lease costs paid	0	0
Distributions from subsidiaries	305,266
Investments in unconsolidated joint ventures		0
Net cash provided by/(used in) investing activities	305,266	0
Cash Flows from Financing Activities:
Debt issuance costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Intercompany note payable	0
Value of shares withheld to pay tax obligations related to employee stock compensation	(737)	(1,128)
Repurchases of common stock as part of announced plan	(233,164)
Dividends paid and discount on dividend reinvestments	(130,104)	(61,080)
Net cash used in financing activities	(364,005)	(998)
Net decrease in cash, cash equivalents, and restricted cash and escrows	0	0
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150	150
Cash, cash equivalents, and restricted cash and escrows, end of period	150	150
Piedmont OP (the Issuer)
Condensed Financial Statements, Captions [Line Items]
Payments for (Proceeds from) Intercompany Distributions		38,103
Net Cash Provided by/(Used in) Operating Activities	56,468	(5,748)
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(2,004)	(407)
Intercompany note receivable	88,000
Net sales proceeds from wholly-owned properties	32,086	(58)
Note receivable issuance	0
Deferred lease costs paid	(5)	(305)
Distributions from subsidiaries	62,437
Investments in unconsolidated joint ventures		(284)
Net cash provided by/(used in) investing activities	180,514	(1,054)
Cash Flows from Financing Activities:
Debt issuance costs paid	(101)	(63)
Proceeds from debt	716,225	100,000
Repayments of debt	(754,000)	(55,000)
Intercompany note payable	0
Value of shares withheld to pay tax obligations related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0
Dividends paid and discount on dividend reinvestments	(198,964)	0
Net cash used in financing activities	(236,840)	6,834
Net decrease in cash, cash equivalents, and restricted cash and escrows	142	32
Cash, cash equivalents, and restricted cash and escrows, beginning of period	3,906	3,693
Cash, cash equivalents, and restricted cash and escrows, end of period	4,048	3,725
Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Payments for (Proceeds from) Intercompany Distributions		23,107
Net Cash Provided by/(Used in) Operating Activities	43,698	55,044
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(38,903)	(27,796)
Intercompany note receivable	0
Net sales proceeds from wholly-owned properties	382,992	(6)
Note receivable issuance	(3,200)
Deferred lease costs paid	(2,591)	(3,965)
Distributions from subsidiaries	0
Investments in unconsolidated joint ventures		0
Net cash provided by/(used in) investing activities	338,298	(31,767)
Cash Flows from Financing Activities:
Debt issuance costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	(359)	(345)
Intercompany note payable	(88,000)
Value of shares withheld to pay tax obligations related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0
Dividends paid and discount on dividend reinvestments	(294,341)	0
Net cash used in financing activities	(382,700)	(23,452)
Net decrease in cash, cash equivalents, and restricted cash and escrows	(704)	(175)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	4,699	4,361
Cash, cash equivalents, and restricted cash and escrows, end of period	$ 3,995	$ 4,186

Subsequent Events (Details)	May 01, 2018 $ / shares
Subsequent Event
Subsequent Event [Line Items]
Dividends declared (in dollars per share)	$ 0.21

Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends to common stockholders per share (in USD per share)	$ 0.21	$ 1.34