Piedmont Office Realty Trust (PDM) 10-Q 1 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	Piedmont Office Realty Trust, Inc.
Entity Central Index Key	1,042,776
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding		128,370,913

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real estate assets, at cost:
Land	$ 547,602	$ 544,794
Buildings and improvements, less accumulated depreciation of $831,692 and $785,206 as of June 30, 2018 and December 31, 2017, respectively	2,409,749	2,418,023
Intangible lease assets, less accumulated amortization of $79,934 and $99,145 as of June 30, 2018 and December 31, 2017, respectively	70,271	77,805
Construction in progress	17,831	11,710
Real estate assets held for sale, net	0	332,410
Total real estate assets	3,045,453	3,384,742
Amounts due from unconsolidated joint ventures	0	10
Cash and cash equivalents	8,944	7,382
Tenant receivables, net of allowance for doubtful accounts of $597 and $539 as of June 30, 2018 and December 31, 2017, respectively	9,323	12,139
Straight-line rent receivables	172,164	163,160
Note receivable	3,200	0
Restricted cash and escrows	1,415	1,373
Prepaid expenses and other assets	29,180	22,517
Goodwill	98,918	98,918
Interest rate swaps	2,679	688
Deferred lease costs, less accumulated amortization of $169,256 and $183,740 as of June 30, 2018 and December 31, 2017, respectively	252,714	261,907
Other assets held for sale, net	0	47,131
Total assets	3,623,990	3,999,967
Liabilities:
Unsecured debt, net of discount and unamortized debt issuance costs of $8,144 and $7,689 as of June 30, 2018 and December 31, 2017, respectively	1,529,856	1,535,311
Secured debt, net of premiums and unamortized debt issuance costs of $795 and $946 as of June 30, 2018 and December 31, 2017, respectively	190,990	191,616
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	94,215	216,653
Deferred income	25,532	29,582
Intangible lease liabilities, less accumulated amortization of $54,540 and $55,847 as of June 30, 2018 and December 31, 2017, respectively	40,341	38,458
Interest rate swaps	0	1,478
Other liabilities held for sale, net	0	380
Total liabilities	1,880,934	2,013,478
Commitments and Contingencies
Stockholders’ Equity:
Shares-in-trust, 150,000,000 shares authorized; none outstanding as of June 30, 2018 or December 31, 2017	0	0
Preferred stock, no par value, 100,000,000 shares authorized; none outstanding as of June 30, 2018 or December 31, 2017	0	0
Common stock, $.01 par value, 750,000,000 shares authorized; 128,370,913 and 142,358,940 shares issued and outstanding as of June 30, 2018 and December 31, 2017, respectively	1,284	1,424
Additional paid-in capital	3,681,127	3,677,360
Cumulative distributions in excess of earnings	(1,953,291)	(1,702,281)
Other comprehensive income	12,141	8,164
Piedmont stockholders’ equity	1,741,261	1,984,667
Noncontrolling interest	1,795	1,822
Total stockholders’ equity	1,743,056	1,986,489
Total liabilities and stockholders’ equity	$ 3,623,990	$ 3,999,967

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Assets:
Intangible lease assets, accumulated amortization	$ 79,934	$ 99,145
Tenant receivables, allowance for doubtful accounts	597	539
Deferred lease costs, accumulated amortization	169,256	183,740
Liabilities:
Intangible lease liabilities, accumulated amortization	$ 54,540	$ 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)	128,370,913	142,358,940
Common stock, shares outstanding (in shares)	128,370,913	142,358,940
Unsecured Debt
Liabilities:
Discount, (premiums) and unamortized debt issuance costs	$ 8,144	$ 7,689
Secured Debt
Liabilities:
Discount, (premiums) and unamortized debt issuance costs	(795)	(946)
Building and improvements
Assets:
Buildings and improvements, accumulated depreciation	$ 831,692	$ 785,206

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues:
Rental income	$ 101,478	$ 118,492	$ 202,932	$ 236,531
Tenant reimbursements	22,047	24,285	45,041	49,122
Property management fee revenue	382	400	691	925
Other property related income	5,267	5,502	10,410	10,564
Total revenues	129,174	148,679	259,074	297,142
Expenses:
Property operating costs	52,637	56,287	104,496	112,117
Depreciation	27,115	30,059	54,260	60,827
Amortization	15,245	19,314	31,978	39,729
General and administrative	8,258	7,528	14,810	15,678
Operating expenses	103,255	113,188	205,544	228,351
Real estate operating income	25,919	35,491	53,530	68,791
Other income (expense):
Interest expense	(15,687)	(18,421)	(29,445)	(36,478)
Other income/(expense)	731	38	1,177	(62)
Equity in income of unconsolidated joint ventures	0	107	0	118
Loss on extinguishment of debt	0	0	(1,680)	0
Gain/(loss) on sale of real estate assets, net	(23)	6,492	45,186	6,439
Net income	10,940	23,707	68,768	38,808
Plus: Net loss applicable to noncontrolling interest	2	3	4	6
Net income applicable to Piedmont	$ 10,942	$ 23,710	$ 68,772	$ 38,814
Per share information – basic and diluted:
Net income applicable to common stockholders (in usd per share)	$ 0.09	$ 0.16	$ 0.52	$ 0.27
Weighted-average common shares outstanding – basic (in shares)	128,346,433	145,412,524	132,090,741	145,350,074
Weighted-average common shares outstanding – diluted (in shares)	128,700,743	145,813,130	132,431,642	145,779,709

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income applicable to Piedmont	$ 10,942	$ 23,710	$ 68,772	$ 38,814
Other comprehensive income:
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	1,747	(911)	3,264	132
Plus: Reclassification of net (gain)/loss included in net income (See Note 6)	(245)	977	807	2,283
Gain on investment in available for sale securities	0	15	0	28
Other comprehensive income	1,502	81	4,071	2,443
Comprehensive income applicable to Piedmont	$ 12,444	$ 23,791	$ 72,843	$ 41,257

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - 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]
Plus: Net loss applicable to noncontrolling interest	6
Net income applicable to Piedmont	38,814
Other comprehensive income	$ 2,443
Balance (in shares) at Jun. 30, 2017	145,490,000
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
Plus: 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	(264,785)	$ (143)		(264,642)
Share repurchases as part of an announced plan (in shares)		(14,343,000)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(55,308)		(51)	(55,234)		(23)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	3,821	$ 3	3,818
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		355,000
Plus: Net loss applicable to noncontrolling interest	4					4
Net income applicable to Piedmont	68,772			68,772
Other comprehensive income	4,071				4,071
Balance at Jun. 30, 2018	$ 1,743,056	$ 1,284	$ 3,681,127	$ (1,953,291)	$ 12,141	$ 1,795
Balance (in shares) at Jun. 30, 2018	128,370,913	128,371,000

Consolidated Statements of Sto7

Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Statement of Stockholders' Equity [Abstract]
Dividends to common stockholders per share (in USD per share)	$ 0.42	$ 1.34

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash Flows from Operating Activities:
Net income	$ 68,768	$ 38,808
Operating distributions received from unconsolidated joint ventures	10	0
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	54,260	60,827
Amortization of debt issuance costs and net settlement of interest rate swaps	(207)	810
Other amortization	29,061	39,034
Loss on extinguishment of debt	(1,665)	0
Stock compensation expense	5,004	5,403
Equity in income of unconsolidated joint ventures	0	(118)
Gain on sale of real estate assets, net	(45,186)	(6,439)
Changes in assets and liabilities:
Increase in tenant and straight-line rent receivables, net	(6,974)	(13,078)
Increase in prepaid expenses and other assets	(6,452)	(6,908)
Cash received upon settlement of interest rate swaps	807	0
Decrease in accounts payable and accrued expenses	(13,672)	(5,471)
Decrease in deferred income	(3,839)	(1,128)
Net cash provided by operating activities	83,245	111,740
Cash Flows from Investing Activities:
Acquisition of real estate assets, related intangibles, and cash held in escrow for acquisitions	(28,176)	0
Capitalized expenditures, net of accruals	(26,476)	(58,320)
Net sales proceeds from wholly-owned properties	419,557	23,023
Investments in unconsolidated joint ventures	0	(284)
Note receivable issuance	(3,200)	0
Deferred lease costs paid	(10,219)	(9,563)
Net cash provided by/(used in) investing activities	351,486	(45,144)
Cash Flows from Financing Activities:
Debt issuance costs paid	(248)	(102)
Proceeds from debt	773,225	147,000
Repayments of debt	(780,721)	(115,694)
Costs of issuance of common stock	0	74
Shares withheld for payment of taxes related to employee stock compensation	(2,213)	(3,380)
Repurchases of common stock as part of announced plan	(266,062)	0
Dividends paid and discount on dividend reinvestments	(157,108)	(91,664)
Net cash used in financing activities	(433,127)	(63,914)
Net increase in cash, cash equivalents, and restricted cash and escrows	1,604	2,682
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	$ 10,359	$ 10,886

Organization

Organization	6 Months Ended
	Jun. 30, 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 June 30, 2018 , Piedmont owned 53 in-service office properties and one redevelopment asset. As of June 30, 2018, Piedmont's 53 in-service office properties comprise approximately 16.2 million square feet of primarily Class A commercial office space and were approximately 90.6% leased. As of June 30, 2018 , approximately 91% 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 Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	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), made 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 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 six months ended June 30, 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. These amounts included: (i) the reclassification of approximately $5.5 million and $10.6 million for the three and six months ended June 30, 2017 , respectively, 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 in conjunction with the adoption of the Revenue Recognition Amendments, as further defined and described below; and (ii) the reclassification of $0.5 million and $1.0 million for the three and six months ended June 30, 2017 , respectively, 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 to property operating costs. Accounting Pronouncements Adopted during the Six Months Ended June 30, 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, Piedmont reclassified approximately $5.5 million and $10.6 million for the three and six months ended June 30, 2017 , respectively, 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. Piedmont did not elect to adopt any practical expedients provided by the Revenue Recognition Amendments. A detail of Piedmont's total revenues for the three months ended June 30, 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 June 30, 2018 Three Months Ended June 30, 2017 Rental income $ 101,478 $ 118,492 Tenant reimbursements 22,047 24,285 Property management fee revenue 382 400 Other property related income 5,267 5,502 Total revenues $ 129,174 $ 148,679 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 include 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 sale of 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 and six months ended June 30, 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, Accounting Standards Update No. 2018-11, Leases (Topic 842) Targeted Improvements ("ASU 2018-11") issued by the FASB allows certain non-lease operating expense reimbursements to be accounted for as part of the lease provided certain criteria are met under an optional practical expedient. 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, ASU 2018-01, and ASU 2018-11 are effective in the first quarter of 2019. Although management continues to evaluate the guidance and disclosures required by these amendments, 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. 2018-07, Stock Compensation (Topic 718), Improvements to NonEmployee Share-Based Payment Accounting ("ASU 2018-07"). The provisions of ASU 2018-07 align accounting for stock based compensation for non-employees for goods and services with existing accounting for similar compensation for employees. The amendments supersede previous guidance on accounting for share-based payments to non-employees codified in the FASB's Accounting Standards Codification ("ASC") 505-50. ASU 2018-07 is effective in the first quarter of 2019, with early adoption permitted at any time provided that the entity has already adopted the provisions of ASC 606. P iedmont does not anticipate any material impact to its consolidated financial statements as a result of adoption. The FASB has issued Accounting Standards Update No. 2016-13, Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). The provisions of ASU 2016-13 replace the "incurred loss" approach with an "expected loss" model for impairing trade and other receivables, held-to-maturity debt securities, net investment in leases, and off-balance-sheet credit exposures, which will generally result in earlier recognition of 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

Acquisitions	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
Acquisitions	Acquisitions During the six months ended June 30, 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

Debt	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Debt	Debt During the six months ended June 30, 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 six months ended June 30, 2018 on its $500 Million Unsecured 2015 Line of Credit of approximately $215.0 million , which brought the outstanding balance on the $500 Million Unsecured 2015 Line of Credit to $238 million as of June 30, 2018. Additionally during the six months ended June 30, 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 reduce the outstanding balance under the $500 Million Unsecured 2015 Line of Credit on the date the proceeds were received. 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 June 30, 2018, the stated interest rate spread on the $250 Million Unsecured 2018 Term 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% . The following table summarizes the terms of Piedmont’s indebtedness outstanding as of June 30, 2018 and December 31, 2017 (in thousands): Facility (1) Stated Rate Effective Rate (2) Maturity Amount Outstanding as of June 30, 2018 December 31, 2017 Secured (Fixed) $35 Million Fixed-Rate Loan (3) 5.55 % 3.75 % 9/1/2021 $ 30,195 $ 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 795 946 Subtotal/Weighted Average (5) 3.81 % 190,990 191,616 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 % (7) 1/31/2019 — 300,000 $500 Million Unsecured 2015 Line of Credit (6) LIBOR + 1.00% 3.08 % 6/18/2019 (8) 238,000 23,000 $300 Million Unsecured 2011 Term Loan LIBOR + 1.15% 3.35 % (7) 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 LIBOR + 1.60% 3.95 % (9) 3/31/2025 250,000 — Discounts and unamortized debt issuance costs (8,144) (7,689) Subtotal/Weighted Average (5) 3.70 % 1,529,856 1,535,311 Total/Weighted Average (5) 3.71 % $ 1,720,846 $ 1,726,927 (1) Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of June 30, 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 June 30, 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) The facility has a stated variable rate; however, Piedmont has entered into interest rate swap agreements which effectively fix, exclusive of changes in Piedmont's credit rating, the rate to that shown as the effective rate. (8) 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. (9) The facility has a stated variable rate; however, Piedmont has entered into interest rate swap agreements which effectively fix, exclusive of changes to Piedmont's credit rating, $150 million of the principal balance to 4.11% through March 29, 2020, and $100 million of the principal balance to 4.21% from March 30, 2020 through the maturity date of the loan. For the remaining variable portion of the loan, Piedmont may periodically 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. The rate presented is the weighted-average rate for the effectively fixed and variable portions of the debt outstanding as of June 30, 2018. Piedmont made interest payments on all debt facilities, including interest rate swap cash settlements, of approximately $14.8 million and $16.7 million for the three months ended June 30, 2018 and 2017 , respectively, and approximately $30.7 million and $36.0 million for the six months ended June 30, 2018 and 2017 , respectively. Also, Piedmont capitalized interest of approximately $346,000 and $35,000 for the three months ended June 30, 2018 and 2017 , respectively, and approximately $0.5 million and $0.1 million for the six months ended June 30, 2018 and 2017 , respectively. As of June 30, 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 June 30, 2018 .

Variable Interest Entities

Variable Interest Entities	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	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 June 30, 2018 and December 31, 2017 is as follows (net carrying amount in millions): Piedmont's % Net Carrying Amount as of Net Carrying Amount as of Entity Ownership of Entity Related Building June 30, 2018 December 31, 2017 Primary Beneficiary Considerations 1201 Eye Street N.W. Associates, LLC 98.6% 1201 Eye Street $ 87.5 $ 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 $ 64.5 $ 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 $ 256.5 $ 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

Derivative Instruments	6 Months Ended
	Jun. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	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. As of June 30, 2018 , Piedmont was party to 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 81 months. A detail of Piedmont’s interest rate derivatives outstanding as of June 30, 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 3 $300 Million Unsecured 2011 Term Loan $ 300 11/22/2016 1/15/2020 Interest rate swaps 2 $250 Million Unsecured 2018 Term Loan $ 100 3/29/2018 3/31/2025 Interest rate swaps 1 $250 Million Unsecured 2018 Term Loan $ 50 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 June 30, 2018 and December 31, 2017 , respectively, is as follows (in thousands): Interest rate swaps classified as: June 30, December 31, Gross derivative assets $ 2,679 $ 688 Gross derivative liabilities — (1,478 ) Net derivative asset/(liability) $ 2,679 $ (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 and six months ended June 30, 2018 and 2017 , respectively, was as follows (in thousands): Three Months Ended Six Months Ended Interest Rate Swaps in Cash Flow Hedging Relationships June 30, June 30, June 30, June 30, Amount of gain/(loss) recognized in OCI $ 1,747 $ (911 ) $ 3,264 $ 132 Amount of previously recorded gain/(loss) reclassified from OCI into Interest Expense $ 245 $ (977 ) $ 451 $ (2,283 ) Amount of gain/(loss) recognized on derivatives reclassified from OCI into Loss on Extinguishment of Debt $ — $ — $ (1,258 ) $ — Total amount of Interest Expense presented in the consolidated statements of income $ 15,687 $ 18,421 $ 29,445 $ 36,478 Total amount of Loss on Extinguishment of Debt presented in the consolidated statements of income (1) $ — $ — $ 1,680 $ — (1) Includes the write-off of approximately $0.4 million of discounts and unamortized debt issuance costs associated with the repayment of debt (see Note 4 ). Piedmont estimates that approximately $2.8 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 and six months ended June 30, 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. Because all of Piedmont's interest rate swaps are in an asset position, if Piedmont were to breach any of the contractual provisions of the derivative contracts, the settlement of its obligations under the agreements would not result in a penalty as of June 30, 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 Finan

Fair Value Measurement of Financial Instruments	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurement of Financial Instruments	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 June 30, 2018 and December 31, 2017 , respectively (in thousands): June 30, 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) $ 8,944 $ 8,944 Level 1 $ 7,382 $ 7,382 Level 1 Tenant receivables, net (1) $ 9,323 $ 9,323 Level 1 $ 12,139 $ 12,139 Level 1 Notes receivable (1) $ 3,200 $ 3,200 Level 1 $ — $ — Level 1 Restricted cash and escrows (1) $ 1,415 $ 1,415 Level 1 $ 1,373 $ 1,373 Level 1 Interest rate swaps $ 2,679 $ 2,679 Level 2 $ 688 $ 688 Level 2 Liabilities: Accounts payable and accrued expenses (1) $ 11,000 $ 11,000 Level 1 $ 126,429 $ 126,429 Level 1 Interest rate swaps $ — $ — Level 2 $ 1,478 $ 1,478 Level 2 Debt, net $ 1,720,846 $ 1,725,912 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 June 30, 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 June 30, 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 June 30, 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.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 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 June 30, 2018 , commitments to fund potential non-incremental capital expenditures over the next five years for tenant improvements totaled approximately $40.0 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 June 30, 2018 , commitments for incremental capital expenditures for tenant improvements associated with executed leases totaled approximately $11.8 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 and $20,000 of such reductions in reimbursement revenues related to such tenant audits/disputes during the three months ended June 30, 2018 and 2017 , respectively, and $0.4 million and $0.3 million of such reductions in reimbursement revenues related to such tenant audits/disputes during the six months ended June 30, 2018 and 2017 , respectively.

Assets Held for Sale

Assets Held for Sale	6 Months Ended
	Jun. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Assets Held for Sale	Assets Held for Sale As of June 30, 2018, no properties met the criteria for held for sale classification. However, during the six months ended June 30, 2018 , Piedmont sold a portfolio of 14 properties (the "2017 Disposition Portfolio"). As of December 31, 2017, the 2017 Disposition Portfolio 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. Details of assets held for sale as of June 30, 2018 and December 31, 2017 are presented below (in thousands): June 30, 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 June 30, 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 June 30, 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 June 30, 2018 and December 31, 2017, respectively $ — $ 380

Stock Based Compensation

Stock Based Compensation	6 Months Ended
	Jun. 30, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Based Compensation	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 six months ended June 30, 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 Deferred Stock Awards Granted 354,236 $ 17.84 Increase in Estimated Potential Share Award 379,249 $ 23.80 Performance Stock Awards Vested (161,005 ) $ 18.47 Deferred Stock Awards Vested (331,195 ) $ 19.21 Deferred Stock Awards Forfeited (6,515 ) $ 19.98 Unvested and Potential Stock Awards as of June 30, 2018 1,103,207 $ 22.42 The following table provides additional information regarding stock award activity during the three and six months ended June 30, 2018 and 2017 , respectively (in thousands, except per share amounts): Three Months Ended Six Months Ended June 30, June 30, June 30, June 30, Weighted-Average Grant Date Fair Value of Deferred Stock Granted During the Period $ 17.84 $ 21.38 $ 17.84 $ 21.38 Total Grant Date Fair Value of Deferred Stock Vested During the Period $ 5,639 $ 5,551 $ 6,363 $ 5,841 Share-based Liability Awards Paid During the Period (1) $ — $ — $ 2,947 $ 2,877 (1) Amounts reflect the issuance of performance share awards related to the 2014-16 and 2015-17 Performance Share Plans during the six months ended June 30, 2018 and 2017 , respectively. A detail of Piedmont’s outstanding stock awards as of June 30, 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 72,969 $ 16.45 Of the shares granted, 20% vested or will vest on January 3, 2015, 2016, 2017, 2018, and 2019, respectively. 16,416 May 24, 2016 Deferred Stock Award 208,055 $ 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. 60,975 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. 119,371 (2) May 18, 2017 Deferred Stock Award 219,947 $ 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. 124,281 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) May 17, 2018 Deferred Stock Award-Board of Directors 31,388 $ 17.84 Of the shares granted, 100% will vest by May 17, 2019. 31,388 May 17, 2018 Deferred Stock Award 302,865 $ 17.84 Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 17, 2019, 2020, and 2021, respectively. 241,409 May 17, 2018 Fiscal Year 2018-2020 Performance Share Program — $ 23.52 Shares awarded, if any, will vest immediately upon determination of award in 2021. 366,032 (2) Total 1,103,207 (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 June 30, 2018 . (2) Estimated based on Piedmont's cumulative TSR for the respective performance period through June 30, 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 June 30, 2018 and 2017 , Piedmont recognized approximately $4.0 million and $2.6 million of compensation expense related to stock awards, of which $2.6 million and $1.1 million is related to the amortization of unvested shares, respectively. During the six months ended June 30, 2018 and 2017 , Piedmont recognized approximately $5.0 million and $5.7 million of compensation expense related to stock awards, of which $3.9 million and $4.2 million is related to the amortization of unvested shares, respectively. During the six months ended June 30, 2018 , a net total of 354,526 shares were issued to employees. As of June 30, 2018 , approximately $6.3 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 two years.

Supplemental Disclosures for th

Supplemental Disclosures for the Statement of Consolidated Cash Flows	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Supplemental Disclosures for the Statement of Consolidated Cash Flows	Supplemental Disclosures for the Statement of Consolidated Cash Flows Certain noncash investing and financing activities for the six months ended June 30, 2018 and 2017 , (in thousands) are outlined below: Six Months Ended June 30, 2018 June 30, 2017 Accrued capital expenditures and deferred lease costs $ 8,920 $ 9,417 Change in accrued dividends and discount on dividend reinvestments $ (101,800 ) $ (30,532 ) Change in accrued share repurchases as part of an announced plan $ (1,277 ) $ — The following table provides a reconciliation of cash, cash equivalents, and restricted cash and escrows as reported, or previously reported, within the consolidated balance sheet to the consolidated statement of cash flows as of the six months ended June 30, 2018 and 2017 , respectively (in thousands). Six Months Ended June 30, 2018 June 30, 2017 Cash and cash equivalents, beginning of period $ 7,382 $ 6,992 Restricted cash and escrows, beginning of period 1,373 1,212 Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows, beginning of period $ 8,755 $ 8,204 Cash and cash equivalents, end of period $ 8,944 $ 9,596 Restricted cash and escrows, end of period 1,415 1,290 Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows, end of period $ 10,359 $ 10,886 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

Earnings Per Share	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Earnings Per Share	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 and six months ended June 30, 2018 and 2017 , respectively (in thousands): Three Months Ended Six Months Ended June 30, 2018 June 30, 2017 June 30, 2018 June 30, 2017 Weighted-average common shares – basic 128,346 145,413 132,091 145,350 Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards 355 400 341 430 Weighted-average common shares – diluted 128,701 145,813 132,432 145,780 Common stock issued and outstanding as of period end 128,371 145,490

Guarantor and Non-Guarantor Fin

Guarantor and Non-Guarantor Financial Information	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Guarantor and Non-Guarantor Financial Information	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 June 30, 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 — 176,704 2,233,345 (300 ) 2,409,749 Intangible lease assets, less accumulated amortization — — 70,271 — 70,271 Construction in progress — 408 17,423 — 17,831 Total real estate assets — 213,206 2,832,547 (300 ) 3,045,453 Cash and cash equivalents 150 5,311 3,483 — 8,944 Tenant and straight-line rent receivables, net — 15,467 166,020 — 181,487 Investment in subsidiaries 1,743,439 2,803,136 169 (4,546,744 ) — Notes receivable — 810 147,700 (145,310 ) 3,200 Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets 77 7,020 26,205 (28 ) 33,274 Goodwill — 98,918 — — 98,918 Deferred lease costs, net — 15,530 237,184 — 252,714 Total assets $ 1,743,666 $ 3,159,398 $ 3,413,308 $ (4,692,382 ) $ 3,623,990 Liabilities: Debt, net $ — $ 1,529,792 $ 336,364 $ (145,310 ) $ 1,720,846 Accounts payable, accrued expenses, and accrued capital expenditures 610 15,012 78,621 (28 ) 94,215 Deferred income — 2,185 23,347 — 25,532 Intangible lease liabilities, net — — 40,341 — 40,341 Total liabilities 610 1,546,989 478,673 (145,338 ) 1,880,934 Equity: Total stockholders’ equity 1,743,056 1,612,409 2,934,635 (4,547,044 ) 1,743,056 Total liabilities and stockholders’ equity $ 1,743,666 $ 3,159,398 $ 3,413,308 $ (4,692,382 ) $ 3,623,990 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 Consolidating Statements of Income For the three months ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 9,238 $ 92,723 $ (483 ) $ 101,478 Tenant reimbursements — 2,195 19,961 (109 ) 22,047 Property management fee revenue — — 4,147 (3,765 ) 382 Other property related income — 29 5,238 — 5,267 — 11,462 122,069 (4,357 ) 129,174 Expenses: Property operating costs — 4,927 52,067 (4,357 ) 52,637 Depreciation — 2,846 24,269 — 27,115 Amortization — 463 14,782 — 15,245 General and administrative 86 1,539 6,633 — 8,258 86 9,775 97,751 (4,357 ) 103,255 Real estate operating income/(loss) (86 ) 1,687 24,318 — 25,919 Other income (expense): Interest expense — (13,953 ) (3,614 ) 1,880 (15,687 ) Other income/(expense) — 36 2,575 (1,880 ) 731 Loss on sale of real estate assets, net — (13 ) (10 ) — (23 ) — (13,930 ) (1,049 ) — (14,979 ) Income/(loss) before consolidated subsidiaries (86 ) (12,243 ) 23,269 — 10,940 Income from subsidiaries 11,028 24,557 — (35,585 ) — Net income 10,942 12,314 23,269 (35,585 ) 10,940 Plus: Net loss applicable to noncontrolling interest — — 2 — 2 Net income applicable to Piedmont $ 10,942 $ 12,314 $ 23,271 $ (35,585 ) $ 10,942 Consolidating Statements of Income For the three months ended June 30, 2017 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 11,068 $ 107,909 $ (485 ) $ 118,492 Tenant reimbursements — 2,966 21,446 (127 ) 24,285 Property management fee revenue — — 4,590 (4,190 ) 400 Other property related income — 22 5,480 — 5,502 — 14,056 139,425 (4,802 ) 148,679 Expenses: Property operating costs — 5,853 55,236 (4,802 ) 56,287 Depreciation — 3,281 26,778 — 30,059 Amortization — 803 18,511 — 19,314 General and administrative 81 1,528 5,919 — 7,528 81 11,465 106,444 (4,802 ) 113,188 Real estate operating income/(loss) (81 ) 2,591 32,981 — 35,491 Other income (expense): Interest expense — (14,810 ) (7,262 ) 3,651 (18,421 ) Other income/(expense) — 2,240 1,449 (3,651 ) 38 Equity in income of unconsolidated joint ventures — 107 — — 107 Gain/(loss) on sale of real estate assets, net — 6,495 (3 ) — 6,492 Net income/(loss) (81 ) (3,377 ) 27,165 — 23,707 Plus: Net loss applicable to noncontrolling interest — — 3 — 3 Net income/(loss) applicable to Piedmont $ (81 ) $ (3,377 ) $ 27,168 $ — $ 23,710 Consolidating Statements of Income For the six months ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 18,052 $ 185,794 $ (914 ) $ 202,932 Tenant reimbursements — 4,840 40,395 (194 ) 45,041 Property management fee revenue — — 8,328 (7,637 ) 691 Other property related income — 57 10,353 — 10,410 — 22,949 244,870 (8,745 ) 259,074 Expenses: Property operating costs — 9,641 103,600 (8,745 ) 104,496 Depreciation — 5,710 48,550 — 54,260 Amortization — 1,074 30,904 — 31,978 General and administrative 186 3,425 11,199 — 14,810 186 19,850 194,253 (8,745 ) 205,544 Real estate operating income/(loss) (186 ) 3,099 50,617 — 53,530 Other income (expense): Interest expense — (25,975 ) (7,312 ) 3,842 (29,445 ) Other income/(expense) — 160 4,859 (3,842 ) 1,177 Loss on extinguishment of debt — (1,680 ) — — (1,680 ) Gain on sale of real estate assets, net — 1,417 43,769 — 45,186 — (26,078 ) 41,316 — 15,238 Income/(loss) before consolidated subsidiaries (186 ) (22,979 ) 91,933 — 68,768 Income from subsidiaries 68,958 92,226 — (161,184 ) — Net income 68,772 69,247 91,933 (161,184 ) 68,768 Plus: Net loss applicable to noncontrolling interest — — 4 — 4 Net income applicable to Piedmont $ 68,772 $ 69,247 $ 91,937 $ (161,184 ) $ 68,772 Consolidating Statements of Income For the six months ended June 30, 2017 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 22,456 $ 215,019 $ (944 ) $ 236,531 Tenant reimbursements — 5,971 43,381 (230 ) 49,122 Property management fee revenue — — 9,226 (8,301 ) 925 Other property related income — 54 10,510 — 10,564 — 28,481 278,136 (9,475 ) 297,142 Expenses: Property operating costs — 11,655 109,937 (9,475 ) 112,117 Depreciation — 6,744 54,083 — 60,827 Amortization — 1,659 38,070 — 39,729 General and administrative 183 3,231 12,264 — 15,678 183 23,289 214,354 (9,475 ) 228,351 Real estate operating income/(loss) (183 ) 5,192 63,782 — 68,791 Other income (expense): Interest expense — (29,254 ) (14,514 ) 7,290 (36,478 ) Other income/(expense) — 4,469 2,759 (7,290 ) (62 ) Equity in income of unconsolidated joint ventures — 118 — — 118 Gain on sale of real estate assets, net — 6,434 5 — 6,439 Net income/(loss) (183 ) (13,041 ) 52,032 — 38,808 Plus: Net loss applicable to noncontrolling interest — — 6 — 6 Net income/(loss) applicable to Piedmont $ (183 ) $ (13,041 ) $ 52,038 $ — $ 38,814 Consolidating Statements of Comprehensive Income For the Three Months Ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Piedmont (Consolidated) Net income $ 10,942 $ 12,314 $ 23,271 $ (35,585 ) $ 10,942 Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges 1,747 1,747 — (1,747 ) 1,747 Plus: Reclassification of gain included in net income (245 ) (245 ) — 245 (245 ) Other comprehensive income 1,502 1,502 — (1,502 ) 1,502 Comprehensive income $ 12,444 $ 13,816 $ 23,271 $ (37,087 ) $ 12,444 Consolidating Statements of Comprehensive Income For the Six Months Ended June 30, 2018 (in thousands) Piedmont Piedmont OP Non-Guarantors Eliminations Piedmont Net income $ 68,772 $ 69,247 $ 91,937 $ (161,184 ) $ 68,772 Effective portion of gain on derivatives instruments that are designated and qualify as cash flow hedges 3,264 3,264 — (3,264 ) 3,264 Plus: Reclassification of net loss included in net income 807 807 — (807 ) 807 Other comprehensive income 4,071 4,071 — (4,071 ) 4,071 Comprehensive income $ 72,843 $ 73,318 $ 91,937 $ (165,255 ) $ 72,843 Condensed Consolidating Statements of Cash Flows For the six months ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Piedmont (Consolidated) Net Cash Provided by Operating Activities $ 71,842 $ 73,022 $ 99,557 $ (161,176 ) $ 83,245 Cash Flows from Investing Activities: Investment in real estate assets and real estate related intangibles, net of accruals — (3,159 ) (51,493 ) — (54,652 ) Intercompany note receivable — 88,000 — (88,000 ) — Net sales proceeds from wholly-owned properties — 36,572 382,985 — 419,557 Note receivable issuance — — (3,200 ) — (3,200 ) Deferred lease costs paid — (20 ) (10,199 ) — (10,219 ) Distributions from subsidiaries 353,518 64,863 — (418,381 ) — Net cash provided by investing activities 353,518 186,256 318,093 (506,381 ) 351,486 Cash Flows from Financing Activities: Debt issuance costs paid — (248 ) — — (248 ) Proceeds from debt — 773,225 — — 773,225 Repayments of debt — (780,000 ) (721 ) — (780,721 ) Intercompany note payable — — (88,000 ) 88,000 — Value of shares withheld to pay tax obligations related to employee stock compensation (2,213 ) — — — (2,213 ) Repurchases of common stock as part of announced plan (266,062 ) — — — (266,062 ) Distributions (157,085 ) (250,818 ) (328,762 ) 579,557 (157,108 ) Net cash used in financing activities (425,360 ) (257,841 ) (417,483 ) 667,557 (433,127 ) Net increase in cash, cash equivalents, and restricted cash and escrows — 1,437 167 — 1,604 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 $ 5,343 $ 4,866 $ — $ 10,359 Condensed Consolidating Statements of Cash Flows For the six months ended June 30, 2017 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Piedmont (Consolidated) Net Cash Provided by/(Used in) Operating Activities $ 3,091 $ (10,029 ) $ 118,678 $ — $ 111,740 Cash Flows from Investing Activities: Investment in real estate assets, consolidated joint venture, and real estate related intangibles, net of accruals — (757 ) (57,563 ) — (58,320 ) Investments in unconsolidated joint ventures — (284 ) — — (284 ) Net sales proceeds from wholly-owned properties — 23,032 (9 ) — 23,023 Deferred lease costs paid — (736 ) (8,827 ) — (9,563 ) Net cash provided by/(used in) investing activities — 21,255 (66,399 ) — (45,144 ) Cash Flows from Financing Activities: Debt issuance costs paid — (102 ) — — (102 ) Proceeds from debt — 147,000 — — 147,000 Repayments of debt — (115,000 ) (694 ) — (115,694 ) Costs of issuance of common stock (74 ) — — — (74 ) Value of shares withheld to pay tax obligations related to employee stock compensation (3,380 ) — — — (3,380 ) (Distributions to)/repayments from affiliates 92,020 (41,618 ) (50,402 ) — — Dividends paid and discount on dividend reinvestments (91,657 ) — (7 ) — (91,664 ) Net cash used in financing activities (3,091 ) (9,720 ) (51,103 ) — (63,914 ) Net increase in cash, cash equivalents, and restricted cash and escrows — 1,506 1,176 — 2,682 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 $ 5,199 $ 5,537 $ — $ 10,886

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Third Quarter Dividend Declaration On August 1, 2018 , the Board of Directors of Piedmont declared dividends for the third quarter 2018 in the amount of $0.21 per common share outstanding to stockholders of record as of the close of business on August 31, 2018 . Such dividends are to be paid on September 21, 2018 .

Summary of Significant Accoun23

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	The consolidated financial statements of Piedmont have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year’s results.
Principles of Consolidation	Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity ("VIE") 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	Use of Estimates The preparation of the accompanying consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying consolidated financial statements and notes. Actual results could differ from those estimates.
Income Taxes	Income Taxes Piedmont has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended, and has operated as such, beginning with its taxable year ended December 31, 1998. To qualify as a REIT, Piedmont must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its annual REIT taxable income. As a REIT, Piedmont is generally not subject to federal income taxes, 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), made 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 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 six months ended June 30, 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	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. These amounts included: (i) the reclassification of approximately $5.5 million and $10.6 million for the three and six months ended June 30, 2017 , respectively, 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 in conjunction with the adoption of the Revenue Recognition Amendments, as further defined and described below; and (ii) the reclassification of $0.5 million and $1.0 million for the three and six months ended June 30, 2017 , respectively, 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 to property operating costs.
Recent Accounting Pronouncements	Accounting Pronouncements Adopted during the Six Months Ended June 30, 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, Piedmont reclassified approximately $5.5 million and $10.6 million for the three and six months ended June 30, 2017 , respectively, 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. Piedmont did not elect to adopt any practical expedients provided by the Revenue Recognition Amendments. A detail of Piedmont's total revenues for the three months ended June 30, 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 June 30, 2018 Three Months Ended June 30, 2017 Rental income $ 101,478 $ 118,492 Tenant reimbursements 22,047 24,285 Property management fee revenue 382 400 Other property related income 5,267 5,502 Total revenues $ 129,174 $ 148,679 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 include 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 sale of 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 and six months ended June 30, 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, Accounting Standards Update No. 2018-11, Leases (Topic 842) Targeted Improvements ("ASU 2018-11") issued by the FASB allows certain non-lease operating expense reimbursements to be accounted for as part of the lease provided certain criteria are met under an optional practical expedient. 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, ASU 2018-01, and ASU 2018-11 are effective in the first quarter of 2019. Although management continues to evaluate the guidance and disclosures required by these amendments, 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. 2018-07, Stock Compensation (Topic 718), Improvements to NonEmployee Share-Based Payment Accounting ("ASU 2018-07"). The provisions of ASU 2018-07 align accounting for stock based compensation for non-employees for goods and services with existing accounting for similar compensation for employees. The amendments supersede previous guidance on accounting for share-based payments to non-employees codified in the FASB's Accounting Standards Codification ("ASC") 505-50. ASU 2018-07 is effective in the first quarter of 2019, with early adoption permitted at any time provided that the entity has already adopted the provisions of ASC 606. P iedmont does not anticipate any material impact to its consolidated financial statements as a result of adoption. The FASB has issued Accounting Standards Update No. 2016-13, Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). The provisions of ASU 2016-13 replace the "incurred loss" approach with an "expected loss" model for impairing trade and other receivables, held-to-maturity debt securities, net investment in leases, and off-balance-sheet credit exposures, which will generally result in earlier recognition of 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.
Risk Management Objective of Using Derivatives	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.

Summary of Significant Accoun24

Summary of Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles	A detail of Piedmont's total revenues for the three months ended June 30, 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 June 30, 2018 Three Months Ended June 30, 2017 Rental income $ 101,478 $ 118,492 Tenant reimbursements 22,047 24,285 Property management fee revenue 382 400 Other property related income 5,267 5,502 Total revenues $ 129,174 $ 148,679

Acquisitions (Tables)

Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
Schedule of Purchased Assets	During the six months ended June 30, 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 (Tables)

Debt (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Schedule of Debt	The following table summarizes the terms of Piedmont’s indebtedness outstanding as of June 30, 2018 and December 31, 2017 (in thousands): Facility (1) Stated Rate Effective Rate (2) Maturity Amount Outstanding as of June 30, 2018 December 31, 2017 Secured (Fixed) $35 Million Fixed-Rate Loan (3) 5.55 % 3.75 % 9/1/2021 $ 30,195 $ 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 795 946 Subtotal/Weighted Average (5) 3.81 % 190,990 191,616 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 % (7) 1/31/2019 — 300,000 $500 Million Unsecured 2015 Line of Credit (6) LIBOR + 1.00% 3.08 % 6/18/2019 (8) 238,000 23,000 $300 Million Unsecured 2011 Term Loan LIBOR + 1.15% 3.35 % (7) 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 LIBOR + 1.60% 3.95 % (9) 3/31/2025 250,000 — Discounts and unamortized debt issuance costs (8,144) (7,689) Subtotal/Weighted Average (5) 3.70 % 1,529,856 1,535,311 Total/Weighted Average (5) 3.71 % $ 1,720,846 $ 1,726,927 (1) Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of June 30, 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 June 30, 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) The facility has a stated variable rate; however, Piedmont has entered into interest rate swap agreements which effectively fix, exclusive of changes in Piedmont's credit rating, the rate to that shown as the effective rate. (8) 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. (9) The facility has a stated variable rate; however, Piedmont has entered into interest rate swap agreements which effectively fix, exclusive of changes to Piedmont's credit rating, $150 million of the principal balance to 4.11% through March 29, 2020, and $100 million of the principal balance to 4.21% from March 30, 2020 through the maturity date of the loan. For the remaining variable portion of the loan, Piedmont may periodically 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. The rate presented is the weighted-average rate for the effectively fixed and variable portions of the debt outstanding as of June 30, 2018.

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2018 and December 31, 2017 is as follows (net carrying amount in millions): Piedmont's % Net Carrying Amount as of Net Carrying Amount as of Entity Ownership of Entity Related Building June 30, 2018 December 31, 2017 Primary Beneficiary Considerations 1201 Eye Street N.W. Associates, LLC 98.6% 1201 Eye Street $ 87.5 $ 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 $ 64.5 $ 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 $ 256.5 $ 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 (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 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 3 $300 Million Unsecured 2011 Term Loan $ 300 11/22/2016 1/15/2020 Interest rate swaps 2 $250 Million Unsecured 2018 Term Loan $ 100 3/29/2018 3/31/2025 Interest rate swaps 1 $250 Million Unsecured 2018 Term Loan $ 50 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 June 30, 2018 and December 31, 2017 , respectively, is as follows (in thousands): Interest rate swaps classified as: June 30, December 31, Gross derivative assets $ 2,679 $ 688 Gross derivative liabilities — (1,478 ) Net derivative asset/(liability) $ 2,679 $ (790 )
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	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 and six months ended June 30, 2018 and 2017 , respectively, was as follows (in thousands): Three Months Ended Six Months Ended Interest Rate Swaps in Cash Flow Hedging Relationships June 30, June 30, June 30, June 30, Amount of gain/(loss) recognized in OCI $ 1,747 $ (911 ) $ 3,264 $ 132 Amount of previously recorded gain/(loss) reclassified from OCI into Interest Expense $ 245 $ (977 ) $ 451 $ (2,283 ) Amount of gain/(loss) recognized on derivatives reclassified from OCI into Loss on Extinguishment of Debt $ — $ — $ (1,258 ) $ — Total amount of Interest Expense presented in the consolidated statements of income $ 15,687 $ 18,421 $ 29,445 $ 36,478 Total amount of Loss on Extinguishment of Debt presented in the consolidated statements of income (1) $ — $ — $ 1,680 $ — (1) Includes the write-off of approximately $0.4 million of discounts and unamortized debt issuance costs associated with the repayment of debt (see Note 4 ).

Fair Value Measurement of Fin29

Fair Value Measurement of Financial Instruments (Tables)	6 Months Ended
	Jun. 30, 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 June 30, 2018 and December 31, 2017 , respectively (in thousands): June 30, 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) $ 8,944 $ 8,944 Level 1 $ 7,382 $ 7,382 Level 1 Tenant receivables, net (1) $ 9,323 $ 9,323 Level 1 $ 12,139 $ 12,139 Level 1 Notes receivable (1) $ 3,200 $ 3,200 Level 1 $ — $ — Level 1 Restricted cash and escrows (1) $ 1,415 $ 1,415 Level 1 $ 1,373 $ 1,373 Level 1 Interest rate swaps $ 2,679 $ 2,679 Level 2 $ 688 $ 688 Level 2 Liabilities: Accounts payable and accrued expenses (1) $ 11,000 $ 11,000 Level 1 $ 126,429 $ 126,429 Level 1 Interest rate swaps $ — $ — Level 2 $ 1,478 $ 1,478 Level 2 Debt, net $ 1,720,846 $ 1,725,912 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.

Assets Held for Sale (Tables)

Assets Held for Sale (Tables)	6 Months Ended
	Jun. 30, 2018
Discontinued Operations and Disposal Groups [Abstract]
Schedule of Assets Held for Sale	Details of assets held for sale as of June 30, 2018 and December 31, 2017 are presented below (in thousands): June 30, 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 June 30, 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 June 30, 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 June 30, 2018 and December 31, 2017, respectively $ — $ 380

Stock Based Compensation (Table

Stock Based Compensation (Tables)	6 Months Ended
	Jun. 30, 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 six months ended June 30, 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 Deferred Stock Awards Granted 354,236 $ 17.84 Increase in Estimated Potential Share Award 379,249 $ 23.80 Performance Stock Awards Vested (161,005 ) $ 18.47 Deferred Stock Awards Vested (331,195 ) $ 19.21 Deferred Stock Awards Forfeited (6,515 ) $ 19.98 Unvested and Potential Stock Awards as of June 30, 2018 1,103,207 $ 22.42 The following table provides additional information regarding stock award activity during the three and six months ended June 30, 2018 and 2017 , respectively (in thousands, except per share amounts): Three Months Ended Six Months Ended June 30, June 30, June 30, June 30, Weighted-Average Grant Date Fair Value of Deferred Stock Granted During the Period $ 17.84 $ 21.38 $ 17.84 $ 21.38 Total Grant Date Fair Value of Deferred Stock Vested During the Period $ 5,639 $ 5,551 $ 6,363 $ 5,841 Share-based Liability Awards Paid During the Period (1) $ — $ — $ 2,947 $ 2,877 (1) Amounts reflect the issuance of performance share awards related to the 2014-16 and 2015-17 Performance Share Plans during the six months ended June 30, 2018 and 2017 , respectively.
Schedule of Outstanding Employee Stock Awards	A detail of Piedmont’s outstanding stock awards as of June 30, 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 72,969 $ 16.45 Of the shares granted, 20% vested or will vest on January 3, 2015, 2016, 2017, 2018, and 2019, respectively. 16,416 May 24, 2016 Deferred Stock Award 208,055 $ 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. 60,975 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. 119,371 (2) May 18, 2017 Deferred Stock Award 219,947 $ 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. 124,281 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) May 17, 2018 Deferred Stock Award-Board of Directors 31,388 $ 17.84 Of the shares granted, 100% will vest by May 17, 2019. 31,388 May 17, 2018 Deferred Stock Award 302,865 $ 17.84 Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 17, 2019, 2020, and 2021, respectively. 241,409 May 17, 2018 Fiscal Year 2018-2020 Performance Share Program — $ 23.52 Shares awarded, if any, will vest immediately upon determination of award in 2021. 366,032 (2) Total 1,103,207 (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 June 30, 2018 . (2) Estimated based on Piedmont's cumulative TSR for the respective performance period through June 30, 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 32

Supplemental Disclosures for the Statement of Consolidated Cash Flows (Tables)	6 Months Ended
	Jun. 30, 2018
Supplemental Cash Flow Elements [Abstract]
Schedule of Cash Flow, Supplemental Disclosures	Certain noncash investing and financing activities for the six months ended June 30, 2018 and 2017 , (in thousands) are outlined below: Six Months Ended June 30, 2018 June 30, 2017 Accrued capital expenditures and deferred lease costs $ 8,920 $ 9,417 Change in accrued dividends and discount on dividend reinvestments $ (101,800 ) $ (30,532 ) Change in accrued share repurchases as part of an announced plan $ (1,277 ) $ — The following table provides a reconciliation of cash, cash equivalents, and restricted cash and escrows as reported, or previously reported, within the consolidated balance sheet to the consolidated statement of cash flows as of the six months ended June 30, 2018 and 2017 , respectively (in thousands). Six Months Ended June 30, 2018 June 30, 2017 Cash and cash equivalents, beginning of period $ 7,382 $ 6,992 Restricted cash and escrows, beginning of period 1,373 1,212 Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows, beginning of period $ 8,755 $ 8,204 Cash and cash equivalents, end of period $ 8,944 $ 9,596 Restricted cash and escrows, end of period 1,415 1,290 Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows, end of period $ 10,359 $ 10,886

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of 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 and six months ended June 30, 2018 and 2017 , respectively (in thousands): Three Months Ended Six Months Ended June 30, 2018 June 30, 2017 June 30, 2018 June 30, 2017 Weighted-average common shares – basic 128,346 145,413 132,091 145,350 Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards 355 400 341 430 Weighted-average common shares – diluted 128,701 145,813 132,432 145,780 Common stock issued and outstanding as of period end 128,371 145,490

Guarantor and Non-Guarantor F34

Guarantor and Non-Guarantor Financial Information (Tables)	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Condensed Consolidated Balance Sheets	Condensed Consolidating Balance Sheets As of June 30, 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 — 176,704 2,233,345 (300 ) 2,409,749 Intangible lease assets, less accumulated amortization — — 70,271 — 70,271 Construction in progress — 408 17,423 — 17,831 Total real estate assets — 213,206 2,832,547 (300 ) 3,045,453 Cash and cash equivalents 150 5,311 3,483 — 8,944 Tenant and straight-line rent receivables, net — 15,467 166,020 — 181,487 Investment in subsidiaries 1,743,439 2,803,136 169 (4,546,744 ) — Notes receivable — 810 147,700 (145,310 ) 3,200 Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets 77 7,020 26,205 (28 ) 33,274 Goodwill — 98,918 — — 98,918 Deferred lease costs, net — 15,530 237,184 — 252,714 Total assets $ 1,743,666 $ 3,159,398 $ 3,413,308 $ (4,692,382 ) $ 3,623,990 Liabilities: Debt, net $ — $ 1,529,792 $ 336,364 $ (145,310 ) $ 1,720,846 Accounts payable, accrued expenses, and accrued capital expenditures 610 15,012 78,621 (28 ) 94,215 Deferred income — 2,185 23,347 — 25,532 Intangible lease liabilities, net — — 40,341 — 40,341 Total liabilities 610 1,546,989 478,673 (145,338 ) 1,880,934 Equity: Total stockholders’ equity 1,743,056 1,612,409 2,934,635 (4,547,044 ) 1,743,056 Total liabilities and stockholders’ equity $ 1,743,666 $ 3,159,398 $ 3,413,308 $ (4,692,382 ) $ 3,623,990 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	Consolidating Statements of Income For the three months ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 9,238 $ 92,723 $ (483 ) $ 101,478 Tenant reimbursements — 2,195 19,961 (109 ) 22,047 Property management fee revenue — — 4,147 (3,765 ) 382 Other property related income — 29 5,238 — 5,267 — 11,462 122,069 (4,357 ) 129,174 Expenses: Property operating costs — 4,927 52,067 (4,357 ) 52,637 Depreciation — 2,846 24,269 — 27,115 Amortization — 463 14,782 — 15,245 General and administrative 86 1,539 6,633 — 8,258 86 9,775 97,751 (4,357 ) 103,255 Real estate operating income/(loss) (86 ) 1,687 24,318 — 25,919 Other income (expense): Interest expense — (13,953 ) (3,614 ) 1,880 (15,687 ) Other income/(expense) — 36 2,575 (1,880 ) 731 Loss on sale of real estate assets, net — (13 ) (10 ) — (23 ) — (13,930 ) (1,049 ) — (14,979 ) Income/(loss) before consolidated subsidiaries (86 ) (12,243 ) 23,269 — 10,940 Income from subsidiaries 11,028 24,557 — (35,585 ) — Net income 10,942 12,314 23,269 (35,585 ) 10,940 Plus: Net loss applicable to noncontrolling interest — — 2 — 2 Net income applicable to Piedmont $ 10,942 $ 12,314 $ 23,271 $ (35,585 ) $ 10,942 Consolidating Statements of Income For the three months ended June 30, 2017 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 11,068 $ 107,909 $ (485 ) $ 118,492 Tenant reimbursements — 2,966 21,446 (127 ) 24,285 Property management fee revenue — — 4,590 (4,190 ) 400 Other property related income — 22 5,480 — 5,502 — 14,056 139,425 (4,802 ) 148,679 Expenses: Property operating costs — 5,853 55,236 (4,802 ) 56,287 Depreciation — 3,281 26,778 — 30,059 Amortization — 803 18,511 — 19,314 General and administrative 81 1,528 5,919 — 7,528 81 11,465 106,444 (4,802 ) 113,188 Real estate operating income/(loss) (81 ) 2,591 32,981 — 35,491 Other income (expense): Interest expense — (14,810 ) (7,262 ) 3,651 (18,421 ) Other income/(expense) — 2,240 1,449 (3,651 ) 38 Equity in income of unconsolidated joint ventures — 107 — — 107 Gain/(loss) on sale of real estate assets, net — 6,495 (3 ) — 6,492 Net income/(loss) (81 ) (3,377 ) 27,165 — 23,707 Plus: Net loss applicable to noncontrolling interest — — 3 — 3 Net income/(loss) applicable to Piedmont $ (81 ) $ (3,377 ) $ 27,168 $ — $ 23,710 Consolidating Statements of Income For the six months ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 18,052 $ 185,794 $ (914 ) $ 202,932 Tenant reimbursements — 4,840 40,395 (194 ) 45,041 Property management fee revenue — — 8,328 (7,637 ) 691 Other property related income — 57 10,353 — 10,410 — 22,949 244,870 (8,745 ) 259,074 Expenses: Property operating costs — 9,641 103,600 (8,745 ) 104,496 Depreciation — 5,710 48,550 — 54,260 Amortization — 1,074 30,904 — 31,978 General and administrative 186 3,425 11,199 — 14,810 186 19,850 194,253 (8,745 ) 205,544 Real estate operating income/(loss) (186 ) 3,099 50,617 — 53,530 Other income (expense): Interest expense — (25,975 ) (7,312 ) 3,842 (29,445 ) Other income/(expense) — 160 4,859 (3,842 ) 1,177 Loss on extinguishment of debt — (1,680 ) — — (1,680 ) Gain on sale of real estate assets, net — 1,417 43,769 — 45,186 — (26,078 ) 41,316 — 15,238 Income/(loss) before consolidated subsidiaries (186 ) (22,979 ) 91,933 — 68,768 Income from subsidiaries 68,958 92,226 — (161,184 ) — Net income 68,772 69,247 91,933 (161,184 ) 68,768 Plus: Net loss applicable to noncontrolling interest — — 4 — 4 Net income applicable to Piedmont $ 68,772 $ 69,247 $ 91,937 $ (161,184 ) $ 68,772 Consolidating Statements of Income For the six months ended June 30, 2017 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Consolidated Revenues: Rental income $ — $ 22,456 $ 215,019 $ (944 ) $ 236,531 Tenant reimbursements — 5,971 43,381 (230 ) 49,122 Property management fee revenue — — 9,226 (8,301 ) 925 Other property related income — 54 10,510 — 10,564 — 28,481 278,136 (9,475 ) 297,142 Expenses: Property operating costs — 11,655 109,937 (9,475 ) 112,117 Depreciation — 6,744 54,083 — 60,827 Amortization — 1,659 38,070 — 39,729 General and administrative 183 3,231 12,264 — 15,678 183 23,289 214,354 (9,475 ) 228,351 Real estate operating income/(loss) (183 ) 5,192 63,782 — 68,791 Other income (expense): Interest expense — (29,254 ) (14,514 ) 7,290 (36,478 ) Other income/(expense) — 4,469 2,759 (7,290 ) (62 ) Equity in income of unconsolidated joint ventures — 118 — — 118 Gain on sale of real estate assets, net — 6,434 5 — 6,439 Net income/(loss) (183 ) (13,041 ) 52,032 — 38,808 Plus: Net loss applicable to noncontrolling interest — — 6 — 6 Net income/(loss) applicable to Piedmont $ (183 ) $ (13,041 ) $ 52,038 $ — $ 38,814
Condensed Statement of Comprehensive Income	Consolidating Statements of Comprehensive Income For the Three Months Ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Piedmont (Consolidated) Net income $ 10,942 $ 12,314 $ 23,271 $ (35,585 ) $ 10,942 Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges 1,747 1,747 — (1,747 ) 1,747 Plus: Reclassification of gain included in net income (245 ) (245 ) — 245 (245 ) Other comprehensive income 1,502 1,502 — (1,502 ) 1,502 Comprehensive income $ 12,444 $ 13,816 $ 23,271 $ (37,087 ) $ 12,444 Consolidating Statements of Comprehensive Income For the Six Months Ended June 30, 2018 (in thousands) Piedmont Piedmont OP Non-Guarantors Eliminations Piedmont Net income $ 68,772 $ 69,247 $ 91,937 $ (161,184 ) $ 68,772 Effective portion of gain on derivatives instruments that are designated and qualify as cash flow hedges 3,264 3,264 — (3,264 ) 3,264 Plus: Reclassification of net loss included in net income 807 807 — (807 ) 807 Other comprehensive income 4,071 4,071 — (4,071 ) 4,071 Comprehensive income $ 72,843 $ 73,318 $ 91,937 $ (165,255 ) $ 72,843
Condensed Consolidated Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows For the six months ended June 30, 2018 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Piedmont (Consolidated) Net Cash Provided by Operating Activities $ 71,842 $ 73,022 $ 99,557 $ (161,176 ) $ 83,245 Cash Flows from Investing Activities: Investment in real estate assets and real estate related intangibles, net of accruals — (3,159 ) (51,493 ) — (54,652 ) Intercompany note receivable — 88,000 — (88,000 ) — Net sales proceeds from wholly-owned properties — 36,572 382,985 — 419,557 Note receivable issuance — — (3,200 ) — (3,200 ) Deferred lease costs paid — (20 ) (10,199 ) — (10,219 ) Distributions from subsidiaries 353,518 64,863 — (418,381 ) — Net cash provided by investing activities 353,518 186,256 318,093 (506,381 ) 351,486 Cash Flows from Financing Activities: Debt issuance costs paid — (248 ) — — (248 ) Proceeds from debt — 773,225 — — 773,225 Repayments of debt — (780,000 ) (721 ) — (780,721 ) Intercompany note payable — — (88,000 ) 88,000 — Value of shares withheld to pay tax obligations related to employee stock compensation (2,213 ) — — — (2,213 ) Repurchases of common stock as part of announced plan (266,062 ) — — — (266,062 ) Distributions (157,085 ) (250,818 ) (328,762 ) 579,557 (157,108 ) Net cash used in financing activities (425,360 ) (257,841 ) (417,483 ) 667,557 (433,127 ) Net increase in cash, cash equivalents, and restricted cash and escrows — 1,437 167 — 1,604 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 $ 5,343 $ 4,866 $ — $ 10,359 Condensed Consolidating Statements of Cash Flows For the six months ended June 30, 2017 (in thousands) Piedmont (Parent) (Guarantor) Piedmont OP (the Issuer) Non-Guarantors Eliminations Piedmont (Consolidated) Net Cash Provided by/(Used in) Operating Activities $ 3,091 $ (10,029 ) $ 118,678 $ — $ 111,740 Cash Flows from Investing Activities: Investment in real estate assets, consolidated joint venture, and real estate related intangibles, net of accruals — (757 ) (57,563 ) — (58,320 ) Investments in unconsolidated joint ventures — (284 ) — — (284 ) Net sales proceeds from wholly-owned properties — 23,032 (9 ) — 23,023 Deferred lease costs paid — (736 ) (8,827 ) — (9,563 ) Net cash provided by/(used in) investing activities — 21,255 (66,399 ) — (45,144 ) Cash Flows from Financing Activities: Debt issuance costs paid — (102 ) — — (102 ) Proceeds from debt — 147,000 — — 147,000 Repayments of debt — (115,000 ) (694 ) — (115,694 ) Costs of issuance of common stock (74 ) — — — (74 ) Value of shares withheld to pay tax obligations related to employee stock compensation (3,380 ) — — — (3,380 ) (Distributions to)/repayments from affiliates 92,020 (41,618 ) (50,402 ) — — Dividends paid and discount on dividend reinvestments (91,657 ) — (7 ) — (91,664 ) Net cash used in financing activities (3,091 ) (9,720 ) (51,103 ) — (63,914 ) Net increase in cash, cash equivalents, and restricted cash and escrows — 1,506 1,176 — 2,682 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 $ 5,199 $ 5,537 $ — $ 10,886

Organization (Details)

Organization (Details) ft² in Millions	6 Months Ended
	Jun. 30, 2018ft²segmentsubsidiarypropertyassetmarket
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	91.00%
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	16.2
Percentage leased	90.60%

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Concentration Risk [Line Items]
Reduction in tax liability			$ 200
Reclassification out of rental income	$ (101,478)	$ (118,492)	(202,932)	$ (236,531)
Reclassification into other property related income	5,267	5,502	10,410	10,564
Reclassification out of general and administrative expenses	(8,258)	(7,528)	(14,810)	(15,678)
Reclassification into property operating costs	$ 52,637	56,287	$ 104,496	112,117
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
Reclassification Adjustment
Concentration Risk [Line Items]
Reclassification out of general and administrative expenses		500		1,000
Reclassification into property operating costs		500		1,000
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		5,500		10,600
Reclassification into other property related income		$ 5,500		$ 10,600

Summary of Significant Accoun37

Summary of Significant Accounting Policies - Revenue Recognition Amendments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accounting Policies [Abstract]
Rental income	$ 101,478	$ 118,492	$ 202,932	$ 236,531
Tenant reimbursements	22,047	24,285	45,041	49,122
Property management fee revenue	382	400	691	925
Other property related income	5,267	5,502	10,410	10,564
Total revenues	$ 129,174	$ 148,679	$ 259,074	$ 297,142

Acquisitions (Details)

Acquisitions (Details) $ in Millions	6 Months Ended
	Jun. 30, 2018USD ($)ft²building
Business Acquisition [Line Items]
Properties acquired | building	1
501 West Church Street
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

Debt (Narrative) (Details)

Debt (Narrative) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)contract	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)contract	Jun. 30, 2017USD ($)
Debt Instrument [Line Items]
Interest paid	$ 14,800,000	$ 16,700,000	$ 30,700,000	$ 36,000,000
Interest costs capitalized	346,000	$ 35,000	500,000	$ 100,000
$300 Million Unsecured 2013 Term Loan | Unsecured Debt
Debt Instrument [Line Items]
Repayment of long-term debt			300,000,000
Face amount of debt instrument	300,000,000		300,000,000
$170 Million Unsecured 2015 Term Loan | Unsecured Debt
Debt Instrument [Line Items]
Repayment of long-term debt			170,000,000
Face amount of debt instrument	170,000,000		170,000,000
$250 Million Unsecured 2018 Term Loan | Unsecured Debt
Debt Instrument [Line Items]
Face amount of debt instrument	250,000,000		$ 250,000,000
Debt instrument term			7 years
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		$ 150,000,000
Line of Credit | $500 Million Unsecured 2015 Line of Credit | Unsecured Debt
Debt Instrument [Line Items]
Amount of line of credit	500,000,000		500,000,000
Net borrowings on lines of credit			215,000,000
Amount outstanding	238,000,000		238,000,000
Face amount of debt instrument	500,000,000		$ 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		$ 450,000,000
Interest rate swaps | $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Number of Swap Agreements | contract	3		3
Notional amount of interest rate swap agreements	$ 150,000,000		$ 150,000,000

Debt (Schedule of Debt) (Detail

Debt (Schedule of Debt) (Details)	6 Months Ended
	Jun. 30, 2018USD ($)period	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Weighted average rate	3.71%
Amount Outstanding	$ 1,720,846,000	$ 1,726,927,000
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
Secured Debt
Debt Instrument [Line Items]
Weighted average rate	3.81%
Amount Outstanding	$ 190,990,000	191,616,000
Net premium, discounts, and unamortized debt issuance costs	$ 795,000	946,000
Secured Debt | $35 Million Fixed-Rate Loan
Debt Instrument [Line Items]
Stated Rate	5.55%
Effective interest rate	3.75%
Amount Outstanding	$ 30,195,000	30,670,000
Face amount of debt instrument	$ 35,000,000
Secured Debt | $160 Million Fixed Rate Loan
Debt Instrument [Line Items]
Stated Rate	3.48%
Effective interest rate	3.58%
Amount Outstanding	$ 160,000,000	160,000,000
Face amount of debt instrument	$ 160,000,000
Unsecured Debt
Debt Instrument [Line Items]
Weighted average rate	3.70%
Amount Outstanding	$ 1,529,856,000	1,535,311,000
Net premium, discounts, and unamortized debt issuance costs	$ (8,144,000)	(7,689,000)
Unsecured Debt | $170 Million Unsecured 2015 Term Loan
Debt Instrument [Line Items]
Effective interest rate	2.54%
Amount Outstanding	$ 0	170,000,000
Face amount of debt instrument	$ 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]
Amount Outstanding	$ 0	300,000,000
Face amount of debt instrument	$ 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]
Effective interest rate	3.08%
Amount Outstanding	$ 238,000,000	23,000,000
Face amount of debt instrument	$ 500,000,000
Maximum extension period	1 year
Number of extension periods | period	2
Extension period	6 months
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]
Amount Outstanding	$ 300,000,000	300,000,000
Face amount of debt instrument	$ 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]
Stated Rate	3.40%
Effective interest rate	3.43%
Amount Outstanding	$ 350,000,000	350,000,000
Face amount of debt instrument	$ 350,000,000
Unsecured Debt | $400 Million Senior Notes
Debt Instrument [Line Items]
Stated Rate	4.45%
Effective interest rate	4.10%
Amount Outstanding	$ 400,000,000	400,000,000
Face amount of debt instrument	$ 400,000,000
Unsecured Debt | $250 Million Unsecured 2018 Term Loan
Debt Instrument [Line Items]
Effective interest rate	3.95%
Amount Outstanding	$ 250,000,000	$ 0
Face amount of debt instrument	250,000,000
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%

Variable Interest Entities (Det

Variable Interest Entities (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Eye Street 1201 N.W. Associates LLC
Variable Interest Entity [Line Items]
Piedmont's %	98.60%
Net Carrying Amount	$ 87.5	$ 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 %	98.10%
Net Carrying Amount	$ 64.5	65.2
Percent of cash flow entitled to entity	100.00%
Piedmont 500 W. Monroe Fee LLC
Variable Interest Entity [Line Items]
Piedmont's %	100.00%
Net Carrying Amount	$ 256.5	$ 263.2
Percent of cash flow entitled to entity	100.00%

Derivative Instruments (Details

Derivative Instruments (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)contract	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)contract	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Derivative [Line Items]
Maximum period of extension term			81 months
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Gross derivative assets	$ 2,679,000		$ 2,679,000		$ 688,000
Gross derivative liabilities	0		0		(1,478,000)
Net derivative asset/(liability)	2,679,000		2,679,000		$ (790,000)
Amount of gain/(loss) recognized in OCI	1,747,000	$ (911,000)	3,264,000	$ 132,000
Total amount of Interest Expense presented in the consolidated statements of income	15,687,000	18,421,000	29,445,000	36,478,000
Total amount of Loss on Extinguishment of Debt presented in the consolidated statements of income	0	0	1,680,000	0
Loss on write off of discount and unamortized debt issuance costs			400,000
Gain (loss) to be reclassified	2,800,000		2,800,000
Gain (loss) from hedge ineffectiveness	0	0	0	0
Interest rate swaps
Derivative [Line Items]
Total Notional Amount (in millions)	450,000,000		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	15,687,000	18,421,000	29,445,000	36,478,000
Interest rate swaps | Interest Expense
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Amount of gain/(loss) recognized in OCI	1,747,000	(911,000)	3,264,000	132,000
Amount of gain/(loss) reclassified from OCI	245,000	(977,000)	451,000	(2,283,000)
Interest rate swaps | Gain (Loss) On Extinguishment Of Debt
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Amount of gain/(loss) reclassified from OCI	$ 0	$ 0	$ (1,258,000)	$ 0
$250 Million Unsecured 2018 Term Loan | Interest rate swaps
Derivative [Line Items]
Number of Swap Agreements | contract	3		3
Total Notional Amount (in millions)	$ 150,000,000		$ 150,000,000
Unsecured Debt | $300 Million Unsecured 2011 Term Loan
Derivative [Line Items]
Face amount of debt instrument	$ 300,000,000		$ 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		3
Total Notional Amount (in millions)	$ 300,000,000		$ 300,000,000
Unsecured Debt | $250 Million Unsecured 2018 Term Loan
Derivative [Line Items]
Face amount of debt instrument	250,000,000		250,000,000
Hedged portion of long-term debt	150,000,000		150,000,000
Total Notional Amount (in millions)	$ 150,000,000		$ 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		2
Total Notional Amount (in millions)	$ 100,000,000		$ 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		1
Total Notional Amount (in millions)	$ 50,000,000		$ 50,000,000

Fair Value Measurement of Fin43

Fair Value Measurement of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	$ 2,679	$ 688
Interest rate swaps	0	1,478
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	8,944	7,382
Restricted cash and escrows	1,415	1,373
Accounts payable and accrued expenses	11,000	126,429
Debt, net	1,720,846	1,726,927
Interest rate swaps | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	2,679	688
Interest rate swaps	0	1,478
Tenant receivables, net | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	9,323	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	8,944	7,382
Restricted cash and escrows	1,415	1,373
Accounts payable and accrued expenses	11,000	126,429
Level 1 | Tenant receivables, net | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	9,323	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	1,725,912	1,759,905
Level 2 | Interest rate swaps | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	2,679	688
Interest rate swaps	$ 0	$ 1,478

Commitments and Contingencies (

Commitments and Contingencies (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)category	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)category	Jun. 30, 2017USD ($)
Loss Contingencies [Line Items]
Number of tenant and building improvement categories | category	2		2
Collectibility of Tenant Reimbursements
Loss Contingencies [Line Items]
Reductions in reimbursement revenues	$ 0	$ 20,000	$ 400,000	$ 300,000
Non-Incremental Capital Expenditures
Loss Contingencies [Line Items]
Period for commitments for funding non-incremental capital expenditures			5 years
Potential obligations for tenant improvements	40,000,000		$ 40,000,000
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	$ 11,800,000		$ 11,800,000

Assets Held for Sale (Assets He

Assets Held for Sale (Assets Held-for-Sale) (Details) $ in Thousands	Jun. 30, 2018USD ($)property	Dec. 31, 2017USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property	14
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 June 30, 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 June 30, 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

Stock Based Compensation (Narra

Stock Based Compensation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense related to stock awards	$ 4	$ 2.6	$ 5	$ 5.7
Compensation expense, non-vested awards	2.6	$ 1.1	$ 3.9	$ 4.2
Total shares issued to employees, directors, and officers (in shares)			354,526
Unrecognized compensation cost related to nonvested	$ 6.3		$ 6.3
Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to nonvested, weighted-average vesting period			2 years
Stock Awards | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			1 year

Stock Based Compensation (Rollf

Stock Based Compensation (Rollforward of Stock Awards) (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
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)	1,103,207		1,103,207
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)	1,103,207		1,103,207
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)			$ 21.69
Unvested and Potential Stock Awards, Weighted-Average Grant Date Fair Value, End of period (in dollars per share)	$ 22.42		$ 22.42
Deferred Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Deferred Stock Awards Granted (in shares)	354,236
Performance Stock Awards and Deferred Stock Awards Vested (in shares)			(331,195)
Deferred Stock Awards Forfeited (in shares)			(6,515)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Deferred Stock Awards Granted (in dollars per share)	$ 17.84	$ 21.38	$ 17.84	$ 21.38
Performance Stock Awards and Deferred Stock Awards Vested, Weighted-Average Grant Date Fair Value (in dollars per share)			19.21
Deferred Stock Awards Forfeited, Weighted-Average Grant Date Fair Value (in dollars per share)			$ 19.98
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Increase in Estimated Potential Share Award, net of forfeitures (in shares)			379,249
Performance Stock Awards and Deferred Stock Awards Vested (in shares)			(161,005)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Increase in Estimated Potential Share Award, net of forfeitures, Weighted-Average Grant Date Fair Value (in dollars per share)			$ 23.80
Performance Stock Awards and Deferred Stock Awards Vested, Weighted-Average Grant Date Fair Value (in dollars per share)			$ 18.47

Stock Based Compensation (Addit

Stock Based Compensation (Additional Information Regarding Stock Award Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Deferred Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average Grant Date Fair Value of Deferred Stock Granted During the Period (in dollars per share)	$ 17.84	$ 21.38	$ 17.84	$ 21.38
Total Grant Date Fair Value of Deferred Stock Vested During the Period	$ 5,639	$ 5,551	$ 6,363	$ 5,841
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Liability Awards Paid During the Period	$ 0	$ 0	$ 2,947	$ 2,877

Stock Based Compensation (Outst

Stock Based Compensation (Outstanding Employee Stock Awards) (Details) - $ / shares	May 17, 2018	May 18, 2017	May 24, 2016	Jan. 03, 2014	Jun. 30, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested Shares (in shares)					1,103,207
Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value (in dollars per share)					$ 22.42	$ 21.69
Unvested Shares (in shares)					1,103,207	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)				72,969
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 24, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)			208,055
Grant Date Fair Value (in dollars per share)			$ 19.91
Unvested Shares (in shares)					60,975
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, Granted May 18, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)		219,947
Grant Date Fair Value (in dollars per share)		$ 21.38
Unvested Shares (in shares)					124,281
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%
Deferred Stock Awards | Deferred Stock Award, Granted May 17, 2018 Deferred Stock Award Independent Directors | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)	31,388
Grant Date Fair Value (in dollars per share)	$ 17.84
Unvested Shares (in shares)					31,388
Deferred Stock Awards | Deferred Stock Award, Granted May 17, 2018 Deferred Stock Award Independent Directors | 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 17, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)	302,865
Grant Date Fair Value (in dollars per share)	$ 17.84
Unvested Shares (in shares)					241,409
Deferred Stock Awards | Deferred Stock Award, Granted May 17, 2018 | 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 17, 2018 | 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 17, 2018 | 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 17, 2018 | 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)					119,371
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
Performance Share Awards | Performance Share Program Award, Granted May 17, 2018
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)	$ 23.52
Unvested Shares (in shares)					366,032

Supplemental Disclosures for 50

Supplemental Disclosures for the Statement of Consolidated Cash Flows (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Supplemental Cash Flow Elements [Abstract]
Accrued capital expenditures and deferred lease costs	$ 8,920	$ 9,417
Change in accrued dividends and discount on dividend reinvestments	(101,800)	(30,532)
Change in accrued share repurchases as part of an announced plan	(1,277)	0
Cash and cash equivalents	8,944	9,596	$ 7,382	$ 6,992
Restricted cash and escrows	1,415	1,290	1,373	1,212
Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows	$ 10,359	$ 10,886	$ 8,755	$ 8,204

Earnings Per Share (Details)

Earnings Per Share (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Earnings Per Share [Abstract]
Weighted-average common shares outstanding – basic (in shares)	128,346,433	145,412,524	132,090,741	145,350,074
Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards (in shares)	355,000	400,000	341,000	430,000
Weighted-average common shares outstanding – diluted (in shares)	128,700,743	145,813,130	132,431,642	145,779,709
Common stock, shares issued (in shares)	128,370,913	145,490,000	128,370,913	145,490,000	142,358,940
Common stock, shares outstanding (in shares)	128,370,913	145,490,000	128,370,913	145,490,000	142,358,940

Guarantor and Non-Guarantor F52

Guarantor and Non-Guarantor Financial Information (Condensed Consolidating Balance Sheets) (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Assets:
Land	$ 547,602	$ 544,794
Buildings and improvements, less accumulated depreciation	2,409,749	2,418,023
Intangible lease assets, less accumulated amortization	70,271	77,805
Construction in progress	17,831	11,710
Real estate assets held for sale, net	0	332,410
Total real estate assets	3,045,453	3,384,742
Cash and cash equivalents	8,944	7,382	$ 9,596	$ 6,992
Tenant and straight-line rent receivables, net	181,487	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	33,274	24,578
Goodwill	98,918	98,918
Deferred lease costs, net	252,714	261,907
Other assets held for sale, net	0	47,131
Total assets	3,623,990	3,999,967
Liabilities:
Debt, net	1,720,846	1,726,927
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	94,215	216,653
Advances from affiliates		0
Deferred income	25,532	29,582
Intangible lease liabilities, net	40,341	38,458
Interest rate swaps	0	1,478
Liabilities held for sale, net	0	380
Total liabilities	1,880,934	2,013,478
Equity:
Total stockholders’ equity	1,743,056	1,986,489		$ 2,097,703
Total liabilities and stockholders’ equity	3,623,990	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	0	0
Advances to affiliates		(7,971,908)
Investment in subsidiaries	(4,546,744)	(3,437,471)
Notes receivable	(145,310)	(233,310)
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	(28)	(740)
Goodwill	0	0
Deferred lease costs, net	0	0
Other assets held for sale, net		0
Total assets	(4,692,382)	(11,643,729)
Liabilities:
Debt, net	(145,310)	(233,310)
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	(28)	(740)
Advances from affiliates		(8,070,163)
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps		0
Liabilities held for sale, net		0
Total liabilities	(145,338)	(8,304,213)
Equity:
Total stockholders’ equity	(4,547,044)	(3,339,516)
Total liabilities and stockholders’ equity	(4,692,382)	(11,643,729)
Piedmont (Parent) (Guarantor) | Reportable Legal Entities
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	0	0
Advances to affiliates		1,674,276
Investment in subsidiaries	1,743,439	3,437,299
Notes receivable	0	0
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	77	2
Goodwill	0	0
Deferred lease costs, net	0	0
Other assets held for sale, net		0
Total assets	1,743,666	5,111,727
Liabilities:
Debt, net	0	0
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	610	104,028
Advances from affiliates		5,277,957
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps		0
Liabilities held for sale, net		0
Total liabilities	610	5,381,985
Equity:
Total stockholders’ equity	1,743,056	(270,258)
Total liabilities and stockholders’ equity	1,743,666	5,111,727
Piedmont OP (the Issuer) | Reportable Legal Entities
Assets:
Land	36,094	36,094
Buildings and improvements, less accumulated depreciation	176,704	180,886
Intangible lease assets, less accumulated amortization	0	181
Construction in progress	408	85
Real estate assets held for sale, net		32,815
Total real estate assets	213,206	250,061
Cash and cash equivalents	5,311	3,890
Tenant and straight-line rent receivables, net	15,467	16,891
Advances to affiliates		6,297,632
Investment in subsidiaries	2,803,136	0
Notes receivable	810	88,810
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	7,020	5,094
Goodwill	98,918	98,918
Deferred lease costs, net	15,530	16,611
Other assets held for sale, net		2,266
Total assets	3,159,398	6,780,173
Liabilities:
Debt, net	1,529,792	1,535,239
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	15,012	20,279
Advances from affiliates		941,494
Deferred income	2,185	3,631
Intangible lease liabilities, net	0	0
Interest rate swaps		1,478
Liabilities held for sale, net		0
Total liabilities	1,546,989	2,502,121
Equity:
Total stockholders’ equity	1,612,409	4,278,052
Total liabilities and stockholders’ equity	3,159,398	6,780,173
Non-Guarantors | Reportable Legal Entities
Assets:
Land	511,508	508,700
Buildings and improvements, less accumulated depreciation	2,233,345	2,237,437
Intangible lease assets, less accumulated amortization	70,271	77,624
Construction in progress	17,423	11,625
Real estate assets held for sale, net		299,595
Total real estate assets	2,832,547	3,134,981
Cash and cash equivalents	3,483	3,342
Tenant and straight-line rent receivables, net	166,020	158,418
Advances to affiliates		0
Investment in subsidiaries	169	172
Notes receivable	147,700	144,500
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	26,205	20,222
Goodwill	0	0
Deferred lease costs, net	237,184	245,296
Other assets held for sale, net		44,865
Total assets	3,413,308	3,751,796
Liabilities:
Debt, net	336,364	424,998
Accounts payable, accrued expenses, dividends payable, and accrued capital expenditures	78,621	93,086
Advances from affiliates		1,850,712
Deferred income	23,347	25,951
Intangible lease liabilities, net	40,341	38,458
Interest rate swaps		0
Liabilities held for sale, net		380
Total liabilities	478,673	2,433,585
Equity:
Total stockholders’ equity	2,934,635	1,318,211
Total liabilities and stockholders’ equity	$ 3,413,308	$ 3,751,796

Guarantor and Non-Guarantor F53

Guarantor and Non-Guarantor Financial Information (Consolidating Statements of Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Revenues:
Rental income	$ 101,478	$ 118,492	$ 202,932	$ 236,531
Tenant reimbursements	22,047	24,285	45,041	49,122
Property management fee revenue	382	400	691	925
Other property related income	5,267	5,502	10,410	10,564
Total revenues	129,174	148,679	259,074	297,142
Expenses:
Property operating costs	52,637	56,287	104,496	112,117
Depreciation	27,115	30,059	54,260	60,827
Amortization	15,245	19,314	31,978	39,729
General and administrative	8,258	7,528	14,810	15,678
Operating expenses	103,255	113,188	205,544	228,351
Real estate operating income	25,919	35,491	53,530	68,791
Other income (expense):
Interest expense	(15,687)	(18,421)	(29,445)	(36,478)
Other income/(expense)	731	38	1,177	(62)
Equity in income of unconsolidated joint ventures	0	107	0	118
Loss on extinguishment of debt	0	0	(1,680)	0
Gain on sale of real estate assets, net	(23)	6,492	45,186	6,439
Other income (expense)	(14,979)		15,238
Income/(loss) before consolidated subsidiaries	10,940		68,768
Income from subsidiaries	0		0
Net income	10,940	23,707	68,768	38,808
Plus: Net loss applicable to noncontrolling interest	2	3	4	6	$ (15)
Net income applicable to Piedmont	10,942	23,710	68,772	38,814	$ 133,564
Eliminations
Revenues:
Rental income	(483)	(485)	(914)	(944)
Tenant reimbursements	(109)	(127)	(194)	(230)
Property management fee revenue	(3,765)	(4,190)	(7,637)	(8,301)
Other property related income	0	0	0	0
Total revenues	(4,357)	(4,802)	(8,745)	(9,475)
Expenses:
Property operating costs	(4,357)	(4,802)	(8,745)	(9,475)
Depreciation	0	0	0	0
Amortization	0	0	0	0
General and administrative	0	0	0	0
Operating expenses	(4,357)	(4,802)	(8,745)	(9,475)
Real estate operating income	0	0	0	0
Other income (expense):
Interest expense	1,880	3,651	3,842	7,290
Other income/(expense)	(1,880)	(3,651)	(3,842)	(7,290)
Equity in income of unconsolidated joint ventures		0		0
Loss on extinguishment of debt			0
Gain on sale of real estate assets, net	0	0	0	0
Other income (expense)	0		0
Income/(loss) before consolidated subsidiaries	0		0
Income from subsidiaries	(35,585)		(161,184)
Net income	(35,585)	0	(161,184)	0
Plus: Net loss applicable to noncontrolling interest	0	0	0	0
Net income applicable to Piedmont	(35,585)	0	(161,184)	0
Reportable Legal Entities
Other income (expense):
Other income (expense)	0
Piedmont (Parent) (Guarantor) | Reportable Legal Entities
Revenues:
Rental income	0	0	0	0
Tenant reimbursements	0	0	0	0
Property management fee revenue	0	0	0	0
Other property related income	0	0	0	0
Total revenues	0	0	0	0
Expenses:
Property operating costs	0	0	0	0
Depreciation	0	0	0	0
Amortization	0	0	0	0
General and administrative	86	81	186	183
Operating expenses	86	81	186	183
Real estate operating income	(86)	(81)	(186)	(183)
Other income (expense):
Interest expense	0	0	0	0
Other income/(expense)	0	0	0	0
Equity in income of unconsolidated joint ventures		0		0
Loss on extinguishment of debt			0
Gain on sale of real estate assets, net	0	0	0	0
Other income (expense)			0
Income/(loss) before consolidated subsidiaries	(86)		(186)
Income from subsidiaries	11,028		68,958
Net income	10,942	(81)	68,772	(183)
Plus: Net loss applicable to noncontrolling interest	0	0	0	0
Net income applicable to Piedmont	10,942	(81)	68,772	(183)
Piedmont OP (the Issuer) | Reportable Legal Entities
Revenues:
Rental income	9,238	11,068	18,052	22,456
Tenant reimbursements	2,195	2,966	4,840	5,971
Property management fee revenue	0	0	0	0
Other property related income	29	22	57	54
Total revenues	11,462	14,056	22,949	28,481
Expenses:
Property operating costs	4,927	5,853	9,641	11,655
Depreciation	2,846	3,281	5,710	6,744
Amortization	463	803	1,074	1,659
General and administrative	1,539	1,528	3,425	3,231
Operating expenses	9,775	11,465	19,850	23,289
Real estate operating income	1,687	2,591	3,099	5,192
Other income (expense):
Interest expense	(13,953)	(14,810)	(25,975)	(29,254)
Other income/(expense)	36	2,240	160	4,469
Equity in income of unconsolidated joint ventures		107		118
Loss on extinguishment of debt			(1,680)
Gain on sale of real estate assets, net	(13)	6,495	1,417	6,434
Other income (expense)	(13,930)		(26,078)
Income/(loss) before consolidated subsidiaries	(12,243)		(22,979)
Income from subsidiaries	24,557		92,226
Net income	12,314	(3,377)	69,247	(13,041)
Plus: Net loss applicable to noncontrolling interest	0	0	0	0
Net income applicable to Piedmont	12,314	(3,377)	69,247	(13,041)
Non-Guarantors | Reportable Legal Entities
Revenues:
Rental income	92,723	107,909	185,794	215,019
Tenant reimbursements	19,961	21,446	40,395	43,381
Property management fee revenue	4,147	4,590	8,328	9,226
Other property related income	5,238	5,480	10,353	10,510
Total revenues	122,069	139,425	244,870	278,136
Expenses:
Property operating costs	52,067	55,236	103,600	109,937
Depreciation	24,269	26,778	48,550	54,083
Amortization	14,782	18,511	30,904	38,070
General and administrative	6,633	5,919	11,199	12,264
Operating expenses	97,751	106,444	194,253	214,354
Real estate operating income	24,318	32,981	50,617	63,782
Other income (expense):
Interest expense	(3,614)	(7,262)	(7,312)	(14,514)
Other income/(expense)	2,575	1,449	4,859	2,759
Equity in income of unconsolidated joint ventures		0		0
Loss on extinguishment of debt			0
Gain on sale of real estate assets, net	(10)	(3)	43,769	5
Other income (expense)	(1,049)		41,316
Income/(loss) before consolidated subsidiaries	23,269		91,933
Income from subsidiaries	0		0
Net income	23,269	27,165	91,933	52,032
Plus: Net loss applicable to noncontrolling interest	2	3	4	6
Net income applicable to Piedmont	$ 23,271	$ 27,168	$ 91,937	$ 52,038

Guarantor and Non-Guarantor F54

Guarantor and Non-Guarantor Financial Information (Consolidating Statements of Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	$ 10,942	$ 23,710	$ 68,772	$ 38,814	$ 133,564
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	1,747	(911)	3,264	132
Plus: Reclassification of gain included in net income	(245)	977	807	2,283
Other comprehensive income	1,502	81	4,071	2,443	$ 6,060
Comprehensive income applicable to Piedmont	12,444	23,791	72,843	41,257
Reportable Legal Entities | Piedmont (Parent) (Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	10,942	(81)	68,772	(183)
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	1,747		3,264
Plus: Reclassification of gain included in net income	(245)		807
Other comprehensive income	1,502		4,071
Comprehensive income applicable to Piedmont	12,444		72,843
Reportable Legal Entities | Piedmont OP (the Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	12,314	(3,377)	69,247	(13,041)
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	1,747		3,264
Plus: Reclassification of gain included in net income	(245)		807
Other comprehensive income	1,502		4,071
Comprehensive income applicable to Piedmont	13,816		73,318
Reportable Legal Entities | Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	23,271	27,168	91,937	52,038
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	0		0
Plus: Reclassification of gain included in net income	0		0
Other comprehensive income	0		0
Comprehensive income applicable to Piedmont	23,271		91,937
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	(35,585)	$ 0	(161,184)	$ 0
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 6)	(1,747)		(3,264)
Plus: Reclassification of gain included in net income	245		(807)
Other comprehensive income	(1,502)		(4,071)
Comprehensive income applicable to Piedmont	$ (37,087)		$ (165,255)

Guarantor and Non-Guarantor F55

Guarantor and Non-Guarantor Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	$ 83,245	$ 111,740
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(54,652)	(58,320)
Intercompany note receivable	0
Investments in unconsolidated joint ventures		(284)
Net sales proceeds from wholly-owned properties	419,557	23,023
Note receivable issuance	(3,200)	0
Deferred lease costs paid	(10,219)	(9,563)
Distributions from subsidiaries	0
Net cash provided by/(used in) investing activities	351,486	(45,144)
Cash Flows from Financing Activities:
Debt issuance costs paid	(248)	(102)
Proceeds from debt	773,225	147,000
Repayments of debt	(780,721)	(115,694)
Intercompany note payable	0
Costs of issuance of common stock	0	(74)
Shares withheld for payment of taxes related to employee stock compensation	(2,213)	(3,380)
Repurchases of common stock as part of announced plan	(266,062)	0
(Distributions to)/repayments from affiliates		0
Dividends paid and discount on dividend reinvestments	(157,108)	(91,664)
Net cash used in financing activities	(433,127)	(63,914)
Net increase in cash, cash equivalents, and restricted cash and escrows	1,604	2,682
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	10,359	10,886
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	(161,176)	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)
Investments in unconsolidated joint ventures		0
Net sales proceeds from wholly-owned properties	0	0
Note receivable issuance	0
Deferred lease costs paid	0	0
Distributions from subsidiaries	(418,381)
Net cash provided by/(used in) investing activities	(506,381)	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
Costs of issuance of common stock		0
Shares withheld for payment of taxes related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0
(Distributions to)/repayments from affiliates		0
Dividends paid and discount on dividend reinvestments	579,557	0
Net cash used in financing activities	667,557	0
Net increase 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) | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	71,842	3,091
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Intercompany note receivable	0
Investments in unconsolidated joint ventures		0
Net sales proceeds from wholly-owned properties	0	0
Note receivable issuance	0
Deferred lease costs paid	0	0
Distributions from subsidiaries	353,518
Net cash provided by/(used in) investing activities	353,518	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
Costs of issuance of common stock		(74)
Shares withheld for payment of taxes related to employee stock compensation	(2,213)	(3,380)
Repurchases of common stock as part of announced plan	(266,062)
(Distributions to)/repayments from affiliates		92,020
Dividends paid and discount on dividend reinvestments	(157,085)	(91,657)
Net cash used in financing activities	(425,360)	(3,091)
Net increase 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) | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	73,022	(10,029)
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(3,159)	(757)
Intercompany note receivable	88,000
Investments in unconsolidated joint ventures		(284)
Net sales proceeds from wholly-owned properties	36,572	23,032
Note receivable issuance	0
Deferred lease costs paid	(20)	(736)
Distributions from subsidiaries	64,863
Net cash provided by/(used in) investing activities	186,256	21,255
Cash Flows from Financing Activities:
Debt issuance costs paid	(248)	(102)
Proceeds from debt	773,225	147,000
Repayments of debt	(780,000)	(115,000)
Intercompany note payable	0
Costs of issuance of common stock		0
Shares withheld for payment of taxes related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0
(Distributions to)/repayments from affiliates		(41,618)
Dividends paid and discount on dividend reinvestments	(250,818)	0
Net cash used in financing activities	(257,841)	(9,720)
Net increase in cash, cash equivalents, and restricted cash and escrows	1,437	1,506
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	5,343	5,199
Non-Guarantors | Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	99,557	118,678
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(51,493)	(57,563)
Intercompany note receivable	0
Investments in unconsolidated joint ventures		0
Net sales proceeds from wholly-owned properties	382,985	(9)
Note receivable issuance	(3,200)
Deferred lease costs paid	(10,199)	(8,827)
Distributions from subsidiaries	0
Net cash provided by/(used in) investing activities	318,093	(66,399)
Cash Flows from Financing Activities:
Debt issuance costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	(721)	(694)
Intercompany note payable	(88,000)
Costs of issuance of common stock		0
Shares withheld for payment of taxes related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0
(Distributions to)/repayments from affiliates		(50,402)
Dividends paid and discount on dividend reinvestments	(328,762)	(7)
Net cash used in financing activities	(417,483)	(51,103)
Net increase in cash, cash equivalents, and restricted cash and escrows	167	1,176
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	$ 4,866	$ 5,537

Subsequent Events (Details)

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