Cover - shares	9 Months Ended
Cover - shares	Sep. 30, 2019	Oct. 29, 2019
Cover page.
Document Type	10-Q
Document Transition Report	false
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Entity File Number	001-34626
Entity Registrant Name	Piedmont Office Realty Trust, Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	58-2328421
Entity Address, Address Line One	5565 Glenridge Connector Ste. 450
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30342
City Area Code	770
Local Phone Number	418-8800
Title of 12(b) Security	Common Stock, $0.01 par value
Trading Symbol	PDM
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		125,783,408
Document Fiscal Year Focus	2019
Amendment Flag	false
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001042776

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Real estate assets, at cost:
Land	$ 506,440	$ 470,432
Buildings and improvements, less accumulated depreciation of $772,122 and $718,070 as of September 30, 2019 and December 31, 2018, respectively	2,327,055	2,121,570
Intangible lease assets, less accumulated amortization of $77,483 and $87,391 as of September 30, 2019 and December 31, 2018, respectively	88,371	77,676
Construction in progress	13,866	15,848
Real estate assets held for sale, net	213,094	331,068
Total real estate assets	3,148,826	3,016,594
Cash and cash equivalents	10,284	4,571
Tenant receivables	10,091	10,800
Straight-line rent receivables	147,197	136,762
Restricted cash and escrows	1,820	1,463
Prepaid expenses and other assets	27,143	24,691
Goodwill	98,918	98,918
Interest rate swaps	0	1,199
Deferred lease costs, less accumulated amortization of $173,490 and $176,919 as of September 30, 2019 and December 31, 2018, respectively	267,616	236,198
Other assets held for sale, net	40,036	61,233
Total assets	3,751,931	3,592,429
Liabilities:
Unsecured debt, net of discount and unamortized debt issuance costs of $8,207 and $9,879 as of September 30, 2019 and December 31, 2018, respectively	1,689,793	1,495,121
Secured debt, net of premiums and unamortized debt issuance costs of $418 and $645 as of September 30, 2019 and December 31, 2018, respectively	189,451	190,351
Accounts payable, accrued expenses and accrued capital expenditures	114,812	93,739
Dividends payable	0	26,972
Deferred income	27,985	28,779
Intangible lease liabilities, less accumulated amortization of $49,613 and $59,144 as of September 30, 2019 and December 31, 2018, respectively	34,970	35,708
Interest rate swaps	6,862	839
Other liabilities held for sale	7,275	8,780
Total liabilities	2,071,148	1,880,289
Commitments and Contingencies (Note 8)	$ 0	$ 0
Stockholders’ Equity:
Shares-in-trust, shares authorized (in shares)	150,000,000	150,000,000
Shares-in-trust, shares outstanding (in shares)	0	0
Shares-in-trust, 150,000,000 shares authorized; none outstanding as of September 30, 2019 or December 31, 2018	$ 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
Preferred stock, no par value, 100,000,000 shares authorized; none outstanding as of September 30, 2019 or December 31, 2018	$ 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 outstanding (in shares)	125,783,408	126,218,554
Common stock, $0.01 par value, 750,000,000 shares authorized; 125,783,408 and 126,218,554 shares issued and outstanding as of September 30, 2019 and December 31, 2018, respectively	$ 1,258	$ 1,262
Additional paid-in capital	3,685,504	3,683,186
Cumulative distributions in excess of earnings	(2,007,438)	(1,982,542)
Other comprehensive income/(loss)	(283)	8,462
Piedmont stockholders’ equity	1,679,041	1,710,368
Noncontrolling interest	1,742	1,772
Total stockholders’ equity	1,680,783	1,712,140
Total liabilities and stockholders’ equity	$ 3,751,931	$ 3,592,429

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets:
Intangible lease assets, accumulated amortization	$ 77,483	$ 87,391
Deferred lease costs, accumulated amortization	173,490	176,919
Liabilities:
Intangible lease liabilities, accumulated amortization	$ 49,613	$ 59,144
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)	125,783,408	126,218,554
Common stock, shares outstanding (in shares)	125,783,408	126,218,554
Secured Debt
Liabilities:
Discount (premiums) and unamortized debt issuance costs	$ 418	$ 645
Unsecured Debt
Liabilities:
Discount (premiums) and unamortized debt issuance costs	8,207	9,879
Building and improvements
Assets:
Buildings and improvements, accumulated depreciation	$ 772,122	$ 718,070

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Consolidated Statements of Income - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Rental and tenant reimbursement revenue	$ 130,579	$ 124,518	$ 382,213	$ 372,491
Total revenues	135,421	129,708	399,025	388,782
Expenses:
Property operating costs	54,613	49,679	158,798	154,175
Depreciation	27,131	26,852	80,004	81,112
Amortization	19,505	14,840	55,666	46,818
Impairment loss on real estate assets	1,953	0	1,953	0
General and administrative	7,950	6,677	29,736	21,487
Operating expenses	111,152	98,048	326,157	303,592
Other income (expense):
Interest expense	(16,145)	(15,849)	(46,750)	(45,294)
Other income	263	303	1,292	1,480
Loss on extinguishment of debt	0	0	0	(1,680)
Gain on sale of real estate assets	32	0	39,370	45,186
Nonoperating income (expense)	(15,850)	(15,546)	(6,088)	(308)
Net income	8,419	16,114	66,780	84,882
Net loss applicable to noncontrolling interest	3	0	3	4
Net income applicable to Piedmont	$ 8,422	$ 16,114	$ 66,783	$ 84,886
Per share information – basic:
Net income applicable to common stockholders (in dollars per share)	$ 0.07	$ 0.13	$ 0.53	$ 0.65
Per share information – diluted:
Net income applicable to common stockholders (in dollars per share)	$ 0.07	$ 0.13	$ 0.53	$ 0.65
Weighted-average common shares outstanding – basic (in shares)	125,783,408	128,371,062	125,684,202	130,837,223
Weighted-average common shares outstanding – diluted (in shares)	126,239,744	128,818,658	126,189,851	131,187,127
Property management fee revenue
Revenues:
Property management and other property related revenue	$ 405	$ 368	$ 2,819	$ 1,059
Other property related income
Revenues:
Property management and other property related revenue	$ 4,437	$ 4,822	$ 13,993	$ 15,232

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income applicable to Piedmont	$ 8,422	$ 8,153	$ 50,208	$ 16,114	$ 10,942	$ 57,830	$ 66,783	$ 84,886
Other comprehensive income/(loss):
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	(1,386)			1,144			(6,874)	4,408
Plus/(less): Reclassification of net loss/(gain) included in net income (See Note 5)	(427)			(434)			(1,871)	373
Other comprehensive income/(loss)	(1,813)	$ (4,137)	$ (2,795)	710	$ 1,502	$ 2,569	(8,745)	4,781
Comprehensive income applicable to Piedmont	$ 6,609			$ 16,824			$ 58,038	$ 89,667

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

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, 2017	$ 1,986,489	$ 1,424	$ 3,677,360	$ (1,702,281)	$ 8,164	$ 1,822
Balance (in shares) at Dec. 31, 2017		142,359,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	(231,888)	$ (125)		(231,763)
Share repurchases as part of an announced plan (in shares)		(12,482,000)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(28,311)		(19)	(28,284)		(8)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	2,901	$ 1	2,900
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		148,000
Net (income)/loss applicable to noncontrolling interest	(2)					(2)
Net income applicable to Piedmont	57,830			57,830
Other comprehensive loss	2,569				2,569
Balance at Mar. 31, 2018	1,789,588	$ 1,300	3,680,241	(1,904,404)	10,639	1,812
Balance (in shares) at Mar. 31, 2018		130,025,000
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		142,359,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (income)/loss applicable to noncontrolling interest	(4)
Net income applicable to Piedmont	84,886
Other comprehensive loss	4,781
Balance at Sep. 30, 2018	1,733,996	$ 1,284	3,682,209	(1,964,135)	12,851	1,787
Balance (in shares) at Sep. 30, 2018		128,371,000
Balance at Mar. 31, 2018	1,789,588	$ 1,300	3,680,241	(1,904,404)	10,639	1,812
Balance (in shares) at Mar. 31, 2018		130,025,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	(32,897)	$ (18)	0	(32,879)
Share repurchases as part of an announced plan (in shares)		(1,861,000)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,997)		(32)	(26,950)		(15)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	920	$ 2	918
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		207,000
Net (income)/loss applicable to noncontrolling interest	(2)					(2)
Net income applicable to Piedmont	10,942			10,942
Other comprehensive loss	1,502				1,502
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		128,371,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,971)		(5)	(26,958)		(8)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	1,087	$ 0	1,087
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		0
Net (income)/loss applicable to noncontrolling interest	0
Net income applicable to Piedmont	16,114			16,114
Other comprehensive loss	710				710
Balance at Sep. 30, 2018	1,733,996	$ 1,284	3,682,209	(1,964,135)	12,851	1,787
Balance (in shares) at Sep. 30, 2018		128,371,000
Balance at Dec. 31, 2018	$ 1,712,140	$ 1,262	3,683,186	(1,982,542)	8,462	1,772
Balance (in shares) at Dec. 31, 2018	126,218,554	126,219,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	$ (12,482)	$ (7)		(12,475)
Share repurchases as part of an announced plan (in shares)		(728,000)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,430)		(48)	(26,375)		(7)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	2,880	$ 1	2,879
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		106,000
Net (income)/loss applicable to noncontrolling interest	1					1
Net income applicable to Piedmont	50,208			50,208
Other comprehensive loss	(2,795)				(2,795)
Balance at Mar. 31, 2019	1,723,522	$ 1,256	3,686,017	(1,971,184)	5,667	1,766
Balance (in shares) at Mar. 31, 2019		125,597,000
Balance at Dec. 31, 2018	$ 1,712,140	$ 1,262	3,683,186	(1,982,542)	8,462	1,772
Balance (in shares) at Dec. 31, 2018	126,218,554	126,219,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (income)/loss applicable to noncontrolling interest	$ (3)
Net income applicable to Piedmont	66,783
Other comprehensive loss	(8,745)
Balance at Sep. 30, 2019	$ 1,680,783	$ 1,258	3,685,504	(2,007,438)	(283)	1,742
Balance (in shares) at Sep. 30, 2019	125,783,408	125,783,000
Balance at Mar. 31, 2019	$ 1,723,522	$ 1,256	3,686,017	(1,971,184)	5,667	1,766
Balance (in shares) at Mar. 31, 2019		125,597,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,522)		(94)	(26,415)		(13)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	1,960	$ 2	1,958
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		186,000
Net (income)/loss applicable to noncontrolling interest	(1)					(1)
Net income applicable to Piedmont	8,153			8,153
Other comprehensive loss	(4,137)				(4,137)
Balance at Jun. 30, 2019	1,702,975	$ 1,258	3,687,881	(1,989,446)	1,530	1,752
Balance (in shares) at Jun. 30, 2019		125,783,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Offering costs	(700)		(700)
Dividends to common stockholders, stockholders of subsidiaries, and dividends reinvested	(26,495)		(74)	(26,414)		(7)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	(1,603)	$ 0	(1,603)
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		0
Net (income)/loss applicable to noncontrolling interest	(3)					(3)
Net income applicable to Piedmont	8,422			8,422
Other comprehensive loss	(1,813)				(1,813)
Balance at Sep. 30, 2019	$ 1,680,783	$ 1,258	$ 3,685,504	$ (2,007,438)	$ (283)	$ 1,742
Balance (in shares) at Sep. 30, 2019	125,783,408	125,783,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash Flows from Operating Activities:
Net income	$ 66,780	$ 84,882
Operating distributions received from unconsolidated joint ventures	0	10
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	80,004	81,112
Amortization of debt issuance costs net of favorable settlement of interest rate swaps	419	(215)
Other amortization	52,057	42,882
Loss on extinguishment of debt	0	1,665
Stock compensation expense	12,365	6,671
Gain on sale of real estate assets	(39,370)	(45,186)
Changes in assets and liabilities:
Increase in tenant and straight-line rent receivables	(10,660)	(12,361)
Increase in prepaid expenses and other assets	(1,958)	(8,496)
Decrease in accounts payable and accrued expenses	(2,496)	(10,377)
Increase/(decrease) in deferred income	1,149	(2,265)
Net cash provided by operating activities	160,243	138,322
Cash Flows from Investing Activities:
Acquisition of real estate assets and intangibles	(326,144)	(28,176)
Capitalized expenditures	(57,368)	(44,998)
Net sales proceeds from wholly-owned properties	180,975	419,554
Note receivable issuance	0	(3,200)
Deferred lease costs paid	(16,632)	(15,831)
Net cash (used in)/provided by investing activities	(219,169)	327,349
Cash Flows from Financing Activities:
Debt issuance and other costs paid	(91)	(947)
Proceeds from debt	550,000	820,061
Repayments of debt	(358,041)	(833,005)
Costs of issuance of common stock	(259)	0
Value of shares withheld for payment of taxes related to employee stock compensation	(3,295)	(2,219)
Repurchases of common stock as part of announced plan	(16,899)	(266,062)
Dividends paid and discount on dividend reinvestments	(106,419)	(184,073)
Net cash provided by/(used in) financing activities	64,996	(466,245)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	6,070	(574)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	6,034	8,755
Cash, cash equivalents, and restricted cash and escrows, end of period	$ 12,104	$ 8,181

Organization	9 Months Ended
Organization	Sep. 30, 2019
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, redevelopment, management, and ownership of commercial real estate properties located primarily in seven major office markets 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, taxable REIT 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 it controls. References to Piedmont herein shall include Piedmont and all of its subsidiaries, including Piedmont OP and its subsidiaries and joint ventures. As of September 30, 2019, Piedmont owned 55 in-service office properties and one 487,000-square foot redevelopment asset primarily in select sub-markets located within seven major office markets: Atlanta, Boston, Dallas, Minneapolis, New York, Orlando, and Washington, D.C. As of September 30, 2019, Piedmont's 55 in-service office properties comprised approximately 17.0 million square feet of primarily Class A commercial office space and were 91.9% leased. Piedmont internally evaluates all of its real estate assets as one operating segment, and accordingly does not report segment information.

Summary of Significant Accounting Policies

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Basis of Presentation and Principles of Consolidation

The consolidated financial statements of Piedmont have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year’s results.

Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity ("VIE") for which Piedmont or any of its wholly-owned subsidiaries is considered to have the power to direct the activities of the entity and the obligation to absorb losses/right to receive benefits, or any entity in which Piedmont or any of its wholly-owned subsidiaries owns a controlling interest. In determining whether Piedmont or Piedmont OP has a controlling interest, the following factors, among others, are considered: equity ownership, voting rights, protective rights of investors, and participatory rights of investors. For further information, refer to the financial statements and footnotes included in Piedmont’s Annual Report on Form 10-K for the year ended December 31, 2018.

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.

Accounting Pronouncements Adopted during the Nine Months Ended September 30, 2019

Leases

During the nine months ended September 30, 2019, Piedmont adopted Accounting Standards Update ("ASU") No. 2016-02, Leases (Topic 842), as well as various associated updates and amendments, which together comprise the requirements for lease accounting under Accounting Standards Codification 842 ("ASC 842"). ASC 842 fundamentally changed the definition of a lease, as well as the accounting for operating leases, by requiring lessees to recognize a liability to make lease payments and a right-of-use asset representing the right to use the leased asset over the term of the lease. ASC 842 also prohibits the capitalization of internal direct salary costs associated with negotiating and executing leases. Accounting for leases by lessors is substantially unchanged from prior practice as lessors continue to recognize lease revenue on a straight-line basis.

In conjunction with the adoption of ASC 842, Piedmont adopted the following optional practical expedients, transition amendments, or made accounting policy elections as follows:

•a package of optional practical expedients which precluded: (1) the reassessment of any expired or existing contracts to determine if they contain a lease or to determine lease classification; and (2) the write-off of any unamortized, previously capitalized, initial direct costs for any existing leases;

•an optional practical transition expedient provided by ASU No. 2018-01 which allowed Piedmont to exclude certain land easements in place as of January 1, 2019 from the new guidance;

•an optional practical expedient provided by ASU No. 2018-11 which allows certain non-lease operating expense reimbursements which are included in the underlying stated lease rate to be accounted for as part of an operating lease where Piedmont is the lessor;

•a transitional amendment which allows for the presentation of comparative periods in the year of adoption under ASC 840 (the former leasing guidance), effectively allowing for an initial adoption of ASC 842 (the new leasing guidance) on January 1, 2019 (the "Comparatives Under ASC 840 Option");

•an accounting policy election allowed by ASC 842 related to a recognition and measurement exception for short-term leases (defined as leases which are 12 months or less in duration) where Piedmont is the lessee. Piedmont's short-term lease expense reasonably reflects its lease commitments under such leases; and

•an accounting policy election allowed by ASU No. 2018-20 which permits Piedmont to exclude sales and other similar taxes from analysis to ascertain whether they are Piedmont's primary obligation (as lessor), and instead exclude such costs from revenue and account for them as costs of the lessee.

The nature of Piedmont's change in accounting principle relates primarily to its accounting for operating leases where Piedmont is a lessee for office space, as prescribed by ASC 842. Due to the adoption of the practical expedients outlined above, Piedmont has not adjusted prior-period information retrospectively, and there is a negligible decrease in net income attributable to Piedmont as a result of accounting for leases where Piedmont is the lessee under ASC 842 as compared to prior operating lease accounting.

Operating leases where Piedmont is the lessee relate primarily to office space in buildings owned by third parties. Piedmont recorded a right to use asset and corresponding lease liability of approximately $0.2 million using Piedmont's incremental

borrowing rate as the lease discount rate. For the three and nine months ended September 30, 2019, Piedmont recognized approximately $18,000 and $55,000 of operating lease costs, respectively. As of September 30, 2019, the weighted-average lease term of Piedmont's right of use assets is two years, and the weighted-average discount rate is 3.35%.

Piedmont evaluates contracts at commencement to determine if the contract contains a lease. If a contract is determined to contain a lease, the lease is evaluated to determine whether it is an operating or a financing lease. All of Piedmont's leases where Piedmont is the lessor are for the lessee's use of space in Piedmont's commercial office properties and are classified as operating leases. Lease payments are typically comprised of both fixed base rental payments and separately billed variable lease payments for reimbursement of services performed by Piedmont for the tenant as prescribed by the lease. Fixed base rental payments, as well as any fixed portion of reimbursement income, are recognized on a straight-line basis over the lease term. Tenant reimbursements are recognized as revenue in the period that the related operating cost is incurred. The option to extend or terminate our leases is specific to each underlying tenant agreement; however, generally Piedmont's leases contain penalties for early terminations. None of Piedmont's leases convey the right for the lessee to purchase the underlying property; however, certain leases convey the right of first offer or first refusal on the potential sale of the underlying real estate to the lessee.

Piedmont's future minimum lease payments from lessees under non-cancelable operating leases where Piedmont is the lessor as of September 30, 2019 is presented below (in thousands):


Years ending December 31:
2019 ⁽¹⁾	$	98,831
2020	382,738
2021	373,740
2022	357,475
2023	323,709
Thereafter	1,433,272
Total	$	2,969,765

⁽¹⁾Reflects rental payments for the fiscal period October 1, 2019 through December 31, 2019.

As required under the Comparatives Under ASC 840 Option described above, Piedmont's future minimum rental income from lessees under non-cancelable operating leases where Piedmont is the lessor as of December 31, 2018 is also presented below (in thousands):


Years ending December 31:
2019	$	370,495
2020	352,541
2021	337,951
2022	324,960
2023	291,603
Thereafter	1,247,649
Total	$	2,925,199

Piedmont recognized the following fixed and variable lease payments, which together comprised rental and tenant reimbursement revenue in the accompanying consolidated statements of income for the three and nine months ended September 30, 2019, respectively, as follows (in thousands):


	Three Months Ended		Nine Months Ended
	September 30, 2019		September 30, 2019
Fixed payments	$	105,207	$	311,503
Variable payments	25,372		70,710
Total Rental and Tenant Reimbursement Revenue	$	130,579	$	382,213

Additionally, ASU No. 2018-19 clarifies that operating lease receivables are within the scope of ASC 842; therefore, in accordance with ASC 842, effective January 1, 2019, Piedmont elected to evaluate the collectibility of its operating lease receivables on a tenant/lease-specific basis and began recognizing changes in the collectibility assessment of its operating lease receivables as a reduction of rental and tenant reimbursement revenue, rather than as a bad debt expense, a component of property operating costs. Consequently, during the three and nine months ended September 30, 2019, Piedmont recognized approximately $65,000 and $24,000 of uncollectible operating lease receivables as a decrease in rental and reimbursement revenue, respectively, and during the three and nine months ended September 30, 2018, Piedmont recognized approximately $0 and $84,000 of expense related to uncollectible operating lease receivables as additional property operating costs, respectively.

Stock Compensation to Non-employees

During the nine months ended September 30, 2019, Piedmont adopted ASU No. 2018-07, Stock Compensation (Topic 718), Improvements to Non-employee 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. ASU 2018-07 requires an entity to remeasure liability-classified awards that have not been settled by the date of adoption and equity-classified awards for which a measurement date has not been established through a cumulative-effect adjustment to retained earnings as of January 1, 2019. Piedmont's only awards affected by ASU 2018-07 are equity-classified award grants to its independent board of directors, which have been historically recognized in the same manner prescribed by the newly adopted standard. As such, there was no cumulative effect adjustment recognized upon adoption.

Reclassifications

Although Piedmont has adopted the transitional amendment under ASC 842 described above, Piedmont has combined the presentation of rental income and tenant reimbursements in the accompanying consolidated statements of income for the prior periods to conform to the current period financial presentation under presentation guidance detailed in Accounting Standards Codification 205 Presentation of Financial Statements. These amounts included the presentation of approximately $101.3 million of rental income, and $23.2 million of tenant reimbursements for the three months ended September 30, 2018 as rental and tenant reimbursement revenue of $124.5 million. For the nine months ended September 30, 2018, these amounts included the presentation of approximately $304.3 million of rental income, and $68.2 million of tenant reimbursements as rental and tenant reimbursement revenue of $372.5 million. Further, we intend to make a similar reclassification for the years ended December 31, 2018 and 2017 in our Form 10-K for the year ending December 31, 2019. We will present approximately $411.7 million of rental income and $92.7 million of tenant reimbursements for the year ended December 31, 2018 as rental and tenant reimbursement revenue of $504.4 million. We will present approximately $455.1 million of rental income and $98.2 million of tenant reimbursements for the year ended December 31, 2017 as rental and tenant reimbursement revenue of $553.3 million. Finally, the subtotal of Revenues less Expenses was removed within the accompanying consolidated statements of income for the three and nine months ended September 30, 2018 to correct the prior period presentation, and will also be removed from prior annual periods in subsequent filings.

Other Recent Accounting Pronouncements

The FASB has issued ASU No. 2016-13, Financial Instruments—Credit Losses (Topic 326), Measurement of Credit Losses on Financial Instruments, as well as ASU No. 2019-04, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, and ASU No. 2019-05, Financial Instruments- Credit Losses: Targeted Transition Relief (collectively the "Credit Loss Amendments"). The provisions of the Credit Loss Amendments 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. Further, the FASB has issued ASU No. 2018-19 Codification Improvements to Topic 326, Financial Instruments - Credit Losses, which is effective concurrent with the Credit Loss Amendments, and excludes receivables arising from operating leases from the scope of the Credit Loss Amendments. Both ASU 2018-19 and the Credit Loss Amendments are 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; however, substantially all of Piedmont's receivables are operating lease receivables and as such, Piedmont does not anticipate any material impact to its consolidated financial statements as a result of adoption of the Credit Loss Amendments and ASU 2018-19.

Debt

9 Months Ended

Sep. 30, 2019

Debt Disclosure [Abstract]

Debt

The following table summarizes the terms of Piedmont’s indebtedness outstanding as of September 30, 2019 and December 31, 2018 (in thousands):


Facility ⁽¹⁾	Stated Rate		Effective Rate ⁽²⁾			Maturity		Amount Outstanding as of
												September 30, 2019	December 31, 2018
Secured (Fixed)







$35 Million Fixed-Rate Loan ⁽³⁾	5.55	%	3.75	%		9/1/2021		$	29,033	$	29,706
$160 Million Fixed-Rate Loan ⁽⁴⁾	3.48	%	3.58	%		7/5/2022		160,000		160,000
Net premium and unamortized debt issuance costs								418		645
Subtotal/Weighted Average ⁽⁵⁾	3.80	%						189,451		190,351
Unsecured (Variable and Fixed)





Amended and Restated $300 Million Unsecured 2011 Term Loan	LIBOR + 1.00%		3.20	%	⁽⁷⁾	11/30/2021		300,000		300,000
$500 Million Unsecured 2018 Line of Credit ⁽⁶⁾	LIBOR + 0.90%		2.95	%		9/30/2022	⁽⁸⁾	398,000		205,000
$350 Million Unsecured Senior Notes	3.40	%	3.43	%		6/01/2023		350,000		350,000
$400 Million Unsecured Senior Notes	4.45	%	4.10	%		3/15/2024		400,000		400,000
$250 Million Unsecured 2018 Term Loan	LIBOR + 1.60%		3.93	%	⁽⁹⁾	3/31/2025		250,000		250,000
Discounts and unamortized debt issuance costs								(8,207)		(9,879)
Subtotal/Weighted Average ⁽⁵⁾	3.58	%						1,689,793		1,495,121
Total/Weighted Average ⁽⁵⁾	3.61	%						$	1,879,244	$	1,685,472

⁽¹⁾Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of September 30, 2019 and December 31, 2018 is interest-only until maturity.

⁽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 September 30, 2019.

⁽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 through the maturity date of the interest rate swap agreements (see Note 5 for more detail).

⁽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 September 29, 2023) 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 September 30, 2019 (see Note 5 for more detail).

Piedmont made interest payments on all debt facilities, including interest rate swap cash settlements, of approximately $17.8 million and $18.0 million for the three months ended September 30, 2019 and 2018, respectively, and approximately $49.7

million and $48.7 million for the nine months ended September 30, 2019 and 2018, respectively. Also, Piedmont capitalized interest of approximately $0.5 million and $0.4 million for the three months ended September 30, 2019 and 2018, respectively, and approximately $1.6 million and $0.8 million for the nine months ended September 30, 2019 and 2018, respectively. As of September 30, 2019, Piedmont believes it was in compliance with all financial covenants associated with its debt instruments. See Note 6 for a description of Piedmont’s estimated fair value of debt as of September 30, 2019.

Derivative Instruments

9 Months Ended

Sep. 30, 2019

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivative Instruments

Risk Management Objective of Using Derivatives

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

Cash Flow Hedges of Interest Rate Risk

Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for Piedmont making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.

As of September 30, 2019, 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 Amended and Restated $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 66 months.

A detail of Piedmont’s interest rate derivatives outstanding as of September 30, 2019 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

Amended and Restated $300 Million Unsecured 2011 Term Loan

300

11/22/2016

1/15/2020

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

100

3/29/2018

3/31/2025

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

3/29/2018

3/29/2020

Total

450

Piedmont presents its interest rate derivatives on its consolidated balance sheets on a gross basis as interest rate swap assets and interest rate swap liabilities. A detail of Piedmont’s interest rate derivatives on a gross and net basis as of September 30, 2019 and December 31, 2018, respectively, is as follows (in thousands):


Interest rate swaps classified as:	September 30, 2019		December 31, 2018
Gross derivative assets	$	—	$	1,199
Gross derivative liabilities	(6,862)		(839)
Net derivative asset/(liability)	$	(6,862)	$	360

The gain/(loss) on Piedmont's interest rate derivatives, including previously settled forward swaps, that was recorded in other comprehensive income ("OCI") and the accompanying consolidated statements of income as a component of interest expense for the three and nine months ended September 30, 2019 and 2018, respectively, was as follows (in thousands):


	Three Months Ended						Nine Months Ended
Interest Rate Swaps in Cash Flow Hedging Relationships	September 30, 2019		September 30, 2018		September 30, 2019		September 30, 2018
Amount of gain/(loss) recognized in OCI	$	(1,386)	$	1,144	$	(6,874)	$	4,408
Amount of previously recorded gain reclassified from OCI into Interest Expense	$	427	$	434	$	1,871	$	885
Amount of 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	$	(16,145)	$	(15,849)	$	(46,750)	$	(45,294)
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.

Piedmont estimates that approximately $0.2 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 nine months ended September 30, 2019 and 2018, respectively.

Additionally, see Note 6 for fair value disclosures of Piedmont's derivative instruments.

Credit-risk-related Contingent Features

Piedmont has agreements with its derivative counterparties that contain a provision whereby if Piedmont defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then Piedmont could also be declared in default on its derivative obligations. If Piedmont were to breach any of the contractual provisions of the derivative contracts, it could be required to settle its liability obligations under the agreements at their termination value of the estimated fair values plus accrued interest, or approximately $7.1 million as of September 30, 2019. Additionally, Piedmont has rights of set-off under certain of its derivative agreements related to potential termination fees and amounts payable under the agreements, if a termination were to occur.

Fair Value Measurement of Financial Instruments

9 Months Ended

Sep. 30, 2019

Fair Value Disclosures [Abstract]

Fair Value Measurement of Financial Instruments

Piedmont considers its cash and cash equivalents, tenant receivables, notes receivable, restricted cash and escrows, accounts payable and accrued expenses, interest rate swap agreements, and debt to meet the definition of financial instruments. The following table sets forth the carrying and estimated fair value for each of Piedmont’s financial instruments, as well as its level within the GAAP fair value hierarchy, as of September 30, 2019 and December 31, 2018, respectively (in thousands):


	September 30, 2019									December 31, 2018
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⁾	$	10,284	$	10,284	Level 1	$	4,571	$	4,571	Level 1
Tenant receivables ⁽¹⁾	$	10,091	$	10,091	Level 1	$	10,800	$	10,800	Level 1

Restricted cash and escrows ⁽¹⁾	$	1,820	$	1,820	Level 1	$	1,463	$	1,463	Level 1
Interest rate swaps	$	—	$	—	Level 2	$	1,199	$	1,199	Level 2
Liabilities:
Accounts payable and accrued expenses ⁽¹⁾	$	14,090	$	14,090	Level 1	$	47,328	$	47,328	Level 1
Interest rate swaps	$	6,862	$	6,862	Level 2	$	839	$	839	Level 2
Debt, net	$	1,879,244	$	1,922,891	Level 2	$	1,685,472	$	1,698,213	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 September 30, 2019 and December 31, 2018; however, to estimate its fair value as disclosed in the table above, Piedmont used 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 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 (further discussed in Note 5) are classified as “Interest rate swap” assets and liabilities in the accompanying consolidated balance sheets and were carried at estimated fair value as of September 30, 2019 and December 31, 2018. The estimated fair value of these derivative instruments was determined using widely accepted valuation techniques such as discounted cash flow analysis based on the contractual terms of the derivatives including the period to maturity of each instrument. Observable market-based inputs, including interest rate curves and implied volatilities, were also used. 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 for both Piedmont and the counterparties that were at risk as of the valuation date. The credit risks of both Piedmont and its counterparties were factored into the calculation of the estimated fair value of the interest rate swaps; however, as of September 30, 2019 and December 31, 2018, this credit valuation adjustment did not comprise a material portion of the estimated fair value. Therefore, Piedmont believes that any unobservable inputs (Level 3) used to determine the estimated fair values of its derivative financial instruments are not significant to the fair value measurements in their entirety, and does not consider any of its derivative financial instruments to be Level 3 assets or liabilities.

- Definition

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

+ References + Details

Stock Based Compensation

9 Months Ended

Sep. 30, 2019

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

Stock Based Compensation

The Compensation Committee of Piedmont's Board of Directors has periodically granted deferred stock award units 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 management employees' long-term equity incentive program is split equally between the time-vested award units 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 of office REITs' TSR. The long-term equity incentives for these certain employees, as well as the peer group, is predetermined by the Board of Directors, advised by an outside compensation consultant. Any shares earned are awarded at the end of the multi-year performance period and vest upon award. The fair values of the multi-year performance share awards are estimated using a Monte Carlo valuation method.

A rollforward of Piedmont's equity based award activity for the nine months ended September 30, 2019 is as follows:


	Shares		Weighted-Average Grant Date Fair Value
Unvested and Potential Stock Awards as of December 31, 2018	1,227,483		$	23.14
Deferred Stock Awards Granted	354,057		$	21.02
Increase in Estimated Potential Share Award based on Performance	260,205		$	28.31
Performance Stock Awards Vested	(352,404)	⁽¹⁾	$	25.83
Deferred Stock Awards Vested	(440,450)	⁽¹⁾	$	19.66
Deferred Stock Awards Forfeited	(14,518)		$	19.16
Unvested and Potential Stock Awards as of September 30, 2019	1,034,373		$	25.10

⁽¹⁾Includes performance share and deferred stock awards that were settled in cash in July 2019 in conjunction with the senior management transition that occurred on June 30, 2019.

The following table provides additional information regarding stock award activity during the three and nine months ended September 30, 2019 and 2018, respectively (in thousands, except per share amounts):


	Three Months Ended						Nine Months Ended
	September 30, 2019		September 30, 2018		September 30, 2019		September 30, 2018
Weighted-Average Grant Date Fair Value of Deferred Stock Granted During the Period	$	—	$	—	$	21.02	$	17.84
Total Grant Date Fair Value of Deferred Stock Vested During the Period	$	—	$	16	$	8,658	$	6,378
Share-based Liability Awards Paid During the Period (1)	$	3,444	$	—	$	6,683	$	2,947

⁽¹⁾Amounts reflect the issuance of performance share awards related to the 2016-18 and 2015-17 Performance Share Plans during the nine months ended September 30, 2019 and 2018, respectively, as well as performance share award liabilities settled in cash in July 2019 for retirement and separation associated with the senior management transition on June 30, 2019.

A detail of Piedmont’s outstanding stock awards as of September 30, 2019 is as follows:


Date of grant	Type of Award	Net Shares Granted ⁽¹⁾	Grant Date Fair Value		Vesting Schedule	Unvested Shares
















May 18, 2017	Deferred Stock Award	196,036	$	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.	40,942
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.	153,368	⁽²⁾

May 17, 2018	Deferred Stock Award	271,169	$	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.	108,255
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.	200,674	⁽²⁾
May 15, 2019	Deferred Stock Award-Board of Directors	25,974	$	20.79	Of the shares granted, 100% will vest by May 15, 2020.	25,974
May 3, 2019	Deferred Stock Award	300,825	$	21.04	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 3, 2020, 2021, and 2022, respectively.	195,119
May 3, 2019	Fiscal Year 2019-2021 Performance Share Program	—	$	29.43	Shares awarded, if any, will vest immediately upon determination of award in 2022.	310,041	⁽²⁾
Total						1,034,373

⁽¹⁾Amounts reflect the total original grant to employees and independent directors, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through September 30, 2019.

⁽²⁾Estimated based on Piedmont's cumulative TSR for the respective performance period through September 30, 2019. Share estimates are subject to change in future periods based upon Piedmont's relative performance compared to its peer group of office REITs' TSR.

During the three months ended September 30, 2019 and 2018, Piedmont recognized approximately $3.8 million and $1.7 million, respectively, of compensation expense related to stock awards all of which is related to the amortization of unvested deferred shares and the fair value adjustment to performance shares. During the nine months ended September 30, 2019 and 2018, Piedmont recognized approximately $12.0 million and $6.7 million, respectively, of compensation expense related to stock awards of which $10.5 million and $5.6 million is related to the amortization of unvested deferred shares and the fair value adjustment to performance shares. During the nine months ended September 30, 2019, a net total of 292,675 shares were issued to employees. As of September 30, 2019, approximately $4.5 million of unrecognized compensation cost related to unvested deferred stock awards remained, which Piedmont will record in its consolidated statements of income over a weighted-average vesting period of approximately one year.

Supplemental Disclosures for the Statement of Consolidated Cash Flows

9 Months Ended

Sep. 30, 2019

Supplemental Cash Flow Elements [Abstract]

Supplemental Disclosures for the Statement of Consolidated Cash Flows

Certain non cash investing and financing activities for the nine months ended September 30, 2019 and 2018, (in thousands) are outlined below:


	Nine Months Ended
	September 30, 2019		September 30, 2018
Accrued capital expenditures and deferred lease costs	$	29,828	$	21,784
Change in accrued dividends and discount on dividend reinvestments	$	(26,972)	$	(101,794)

Change in accrued share repurchases as part of an announced plan	$	(4,417)	$	(1,277)
Accrued stock issuance costs	$	441	$	—

The following table provides a reconciliation of cash, cash equivalents, and restricted cash and escrows as presented in the accompanying consolidated statement of cash flows for the nine months ended September 30, 2019 and 2018, to the consolidated balance sheets for the respective period (in thousands):


	2019		2018
Cash and cash equivalents as of January 1, 2019 and 2018, respectively	$	4,571	$	7,382
Restricted cash and escrows as of January 1, 2019 and 2018, respectively	1,463		1,373


Cash, cash equivalents, and restricted cash and escrows, beginning of period, as presented in the accompanying consolidated statement of cash flows	$	6,034	$	8,755

Cash and cash equivalents as of September 30, 2019 and 2018, respectively	$	10,284	$	6,807
Restricted cash and escrows as of September 30, 2019 and 2018, respectively	1,820		1,374


Cash, cash equivalents, and restricted cash and escrows, end of period, as presented in the accompanying consolidated statement of cash flows	$	12,104	$	8,181

Amounts in restricted cash and escrows typically represent escrow accounts for the payment of real estate taxes which are required under certain of Piedmont's debt agreements; earnest money deposited by a buyer to secure the purchase of one of Piedmont's properties; or security or utility deposits held for tenants as a condition of their lease agreement.

Guarantor and Non-Guarantor Financial Information

9 Months Ended

Sep. 30, 2019

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Guarantor and Non-Guarantor Financial Information

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


Condensed Consolidating Balance Sheets
As of September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Assets:
Real estate assets, at cost:
Land	$	—	$	36,094	$	470,346	$	—	$	506,440
Buildings and improvements, less accumulated depreciation	—		186,269		2,141,086		(300)		2,327,055
Intangible lease assets, less accumulated amortization	—		—		88,371		—		88,371
Construction in progress	—		1,058		12,808		—		13,866
Real estate assets held for sale, net	—		—		213,094		—		213,094
Total real estate assets	—		223,421		2,925,705		(300)		3,148,826

Cash and cash equivalents	150		5,758		4,376		—		10,284
Tenant and straight-line rent receivables	—		16,514		140,774		—		157,288
Investment in subsidiaries	1,681,492		3,037,093		162		(4,718,747)		—
Notes receivable	—		810		144,500		(145,310)		—
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	35		6,227		22,710		(9)		28,963
Goodwill	—		98,918		—		—		98,918


Deferred lease costs, net	—		16,567		251,049		—		267,616
Other assets held for sale, net			—		40,036		—		40,036
Total assets	$	1,681,677	$	3,405,308	$	3,529,312	$	(4,864,366)	$	3,751,931
Liabilities:
Debt, net	$	—	$	1,689,749	$	334,805	$	(145,310)	$	1,879,244
Accounts payable, accrued expenses, and accrued capital expenditures	894		16,054		97,873		(9)		114,812
Deferred income	—		3,693		24,292		—		27,985
Intangible lease liabilities, net	—		—		34,970		—		34,970
Interest rate swaps	—		6,862		—		—		6,862
Liabilities held for sale	—		—		7,275		—		7,275
Total liabilities	894		1,716,358		499,215		(145,319)		2,071,148
Equity:
Total stockholders’ equity	1,680,783		1,688,950		3,030,097		(4,719,047)		1,680,783
Total liabilities and stockholders’ equity	$	1,681,677	$	3,405,308	$	3,529,312	$	(4,864,366)	$	3,751,931


Condensed Consolidating Balance Sheets
As of December 31, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Assets:
Real estate assets, at cost:
Land	$	—	$	36,094	$	434,338	$	—	$	470,432
Buildings and improvements, less accumulated depreciation	—		176,927		1,944,943		(300)		2,121,570
Intangible lease assets, less accumulated amortization	—		—		77,676		—		77,676
Construction in progress	—		5,708		10,140		—		15,848
Real estate assets held for sale, net	—		—		331,068		—		331,068
Total real estate assets	—		218,729		2,798,165		(300)		3,016,594

Cash and cash equivalents	150		—		4,939		(518)		4,571
Tenant and straight-line rent receivables	—		16,143		131,419		—		147,562

Investment in subsidiaries	1,744,122		2,704,337		166		(4,448,625)		—
Notes receivable	—		810		144,500		(145,310)		—
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	42		5,682		21,653		(24)		27,353
Goodwill	—		98,918		—		—		98,918


Deferred lease costs, net	—		15,158		221,040		—		236,198
Other assets held for sale, net	—		—		61,233		—		61,233
Total assets	$	1,744,314	$	3,059,777	$	3,383,115	$	(4,594,777)	$	3,592,429
Liabilities:
Debt, net	$	—	$	1,495,065	$	335,717	$	(145,310)	$	1,685,472
Accounts payable, accrued expenses, dividends payable, interest rate swaps and accrued capital expenditures	32,174		15,382		74,536		(542)		121,550

Deferred income	—		2,274		26,505		—		28,779
Intangible lease liabilities, net	—		—		35,708		—		35,708

Liabilities held for sale	—		—		8,780		—		8,780
Total liabilities	32,174		1,512,721		481,246		(145,852)		1,880,289
Equity:
Total stockholders’ equity	1,712,140		1,547,056		2,901,869		(4,448,925)		1,712,140
Total liabilities and stockholders’ equity	$	1,744,314	$	3,059,777	$	3,383,115	$	(4,594,777)	$	3,592,429

Guarantor and Non-Guarantor Financial Information


Consolidating Statements of Income
For the Three Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	11,940	$	119,385	$	(746)	$	130,579
Property management fee revenue	—		—		4,622		(4,217)		405
Other property related income	—		40		4,397		—		4,437
	—		11,980		128,404		(4,963)		135,421
Expenses:
Property operating costs	36		5,507		54,033		(4,963)		54,613
Depreciation	—		3,062		24,069		—		27,131
Amortization	—		486		19,019		—		19,505
Impairment loss on real estate assets	—		—		1,953		—		1,953
General and administrative	(30)		1,547		6,433		—		7,950
	6		10,602		105,507		(4,963)		111,152

Other income (expense):
Interest expense	—		(14,429)		(3,610)		1,894		(16,145)
Other income/(expense)	—		16		2,141		(1,894)		263




Gain on sale of real estate assets	—		—		32		—		32






Income/(loss) before consolidated subsidiaries	(6)		(13,035)		21,460		—		8,419
Income from subsidiaries	8,428		22,929		—		(31,357)		—
Net income	8,422		9,894		21,460		(31,357)		8,419
Plus: Net loss applicable to noncontrolling interest	—		—		3		—		3
Net income applicable to Piedmont	$	8,422	$	9,894	$	21,463	$	(31,357)	$	8,422



Consolidating Statements of Income
For the Three Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	10,861	$	114,351	$	(694)	$	124,518
Property management fee revenue	—		—		4,296		(3,928)		368
Other property related income	—		35		4,787		—		4,822
	—		10,896		123,434		(4,622)		129,708
Expenses:
Property operating costs	—		4,973		49,328		(4,622)		49,679
Depreciation	—		2,816		24,036		—		26,852
Amortization	—		446		14,394		—		14,840

General and administrative	42		1,424		5,211		—		6,677
	42		9,659		92,969		(4,622)		98,048

Other income (expense):
Interest expense	—		(14,119)		(3,624)		1,894		(15,849)
Other income/(expense)	—		40		2,157		(1,894)		303




	—		(14,079)		(1,467)		—		(15,546)
Income/(loss) before consolidated subsidiaries	(42)		(12,842)		28,998		—		16,114





Income from subsidiaries	16,156		26,787		—		(42,943)		—
Net income	16,114		13,945		28,998		(42,943)		16,114
Plus: Net loss applicable to noncontrolling interest	—		—		—		—		—
Net income applicable to Piedmont	$	16,114	$	13,945	$	28,998	$	(42,943)	$	16,114

Guarantor and Non-Guarantor Financial Information


Consolidating Statements of Income
For the Nine Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	33,754	$	340,539	$	(1,802)	$	372,491
Property management fee revenue	—		—		12,625		(11,566)		1,059
Other property related income	—		92		15,140		—		15,232
	—		33,846		368,304		(13,368)		388,782
Expenses:
Property operating costs	—		14,614		152,929		(13,368)		154,175
Depreciation	—		8,527		72,585		—		81,112
Amortization	—		1,520		45,298		—		46,818

General and administrative	228		4,849		16,410		—		21,487
	228		29,510		287,222		(13,368)		303,592

Other income (expense):
Interest expense	—		(40,093)		(10,937)		5,736		(45,294)
Other income/(expense)	—		200		7,016		(5,736)		1,480



Loss on extinguishment of debt	—		(1,680)		—		—		(1,680)
Gain on sale of real estate assets	—		1,417		43,769		—		45,186
	—		(40,156)		39,848		—		(308)
Income/(loss) before consolidated subsidiaries	(228)		(35,820)		120,930		—		84,882





Income from subsidiaries	85,114		119,013		—		(204,127)		—
Net income	84,886		83,193		120,930		(204,127)		84,882

Plus: Net loss applicable to noncontrolling interest	—		—		4		—		4
Net income applicable to Piedmont	$	84,886	$	83,193	$	120,934	$	(204,127)	$	84,886

Guarantor and Non-Guarantor Financial Information


Consolidating Statements of Comprehensive Income
For the Three Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	8,422	$	9,894	$	21,463	$	(31,357)	$	8,422
Other comprehensive loss:
Effective portion of loss on derivative instruments that are designated and qualify as cash flow hedges	(1,386)		(1,386)		—		1,386		(1,386)
Less: Reclassification of net gain included in net income	(427)		(427)		—		427		(427)
Other comprehensive loss	(1,813)		(1,813)		—		1,813		(1,813)

Comprehensive income	$	6,609	$	8,081	$	21,463	$	(29,544)	$	6,609


Consolidating Statements of Comprehensive Income
For the Three Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	16,114	$	13,945	$	28,998	$	(42,943)	$	16,114
Other comprehensive income:
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,144		1,144		—		(1,144)		1,144
Less: Reclassification of net gain included in net income	(434)		(434)		—		434		(434)
Other comprehensive income	710		710		—		(710)		710

Comprehensive income	$	16,824	$	14,655	$	28,998	$	(43,653)	$	16,824

Guarantor and Non-Guarantor Financial Information


Consolidating Statements of Comprehensive Income
For the Nine Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	66,783	$	34,071	$	104,925	$	(138,996)	$	66,783
Other comprehensive loss:
Effective portion of loss on derivative instruments that are designated and qualify as cash flow hedges	(6,874)		(6,874)		—		6,874		(6,874)
Less: Reclassification of net gain included in net income	(1,871)		(1,871)		—		1,871		(1,871)
Other comprehensive loss	(8,745)		(8,745)		—		8,745		(8,745)

Comprehensive income	$	58,038	$	25,326	$	104,925	$	(130,251)	$	58,038


Consolidating Statements of Comprehensive Income
For the Nine Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	84,886	$	83,193	$	120,934	$	(204,127)	$	84,886
Other comprehensive income:
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	4,408		4,408		—		(4,408)		4,408
Plus: Reclassification of net loss included in net income	373		373		—		(373)		373
Other comprehensive income	4,781		4,781		—		(4,781)		4,781

Comprehensive income	$	89,667	$	87,974	$	120,934	$	(208,908)	$	89,667

Guarantor and Non-Guarantor Financial Information


Condensed Consolidating Statements of Cash Flows
For the Nine Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net Cash Provided by Operating Activities	$	89,540	$	89,639	$	164,063	$	(204,920)	$	138,322

Cash Flows from Investing Activities:
Investment in real estate assets and intangibles	—		(6,074)		(67,100)		—		(73,174)
Intercompany note receivable	—		88,000		—		(88,000)		—



Net sales proceeds from wholly-owned properties	—		36,572		382,982		—		419,554


Note receivable issuance	—		—		(3,200)		—		(3,200)
Deferred lease costs paid	—		(1,826)		(14,005)		—		(15,831)
Distributions from subsidiaries	362,784		64,633		—		(427,417)		—
Net cash provided by investing activities	362,784		181,305		298,677		(515,417)		327,349
Cash Flows from Financing Activities:
Debt issuance costs paid	—		(947)		—		—		(947)
Proceeds from debt	—		820,061		—		—		820,061
Repayments of debt	—		(832,000)		(1,005)		—		(833,005)

Intercompany note payable	—		—		(88,000)		88,000		—

Value of shares withheld to pay tax obligations related to employee stock compensation	(2,219)		—		—		—		(2,219)
Repurchases of common stock as part of announced plan	(266,062)		—		—		—		(266,062)

Distributions	(184,043)		(258,907)		(373,460)		632,337		(184,073)
Net cash used in financing activities	(452,324)		(271,793)		(462,465)		720,337		(466,245)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—		(849)		275		—		(574)
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	$	3,057	$	4,974	$	—	$	8,181

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Basis of Presentation

Principles of Consolidation

All intercompany balances and transactions have been eliminated upon consolidation.

Use of Estimates

Income Taxes

Recent Accounting Pronouncements

Accounting Pronouncements Adopted during the Nine Months Ended September 30, 2019

Leases

In conjunction with the adoption of ASC 842, Piedmont adopted the following optional practical expedients, transition amendments, or made accounting policy elections as follows:

•an optional practical transition expedient provided by ASU No. 2018-01 which allowed Piedmont to exclude certain land easements in place as of January 1, 2019 from the new guidance;

Piedmont's future minimum lease payments from lessees under non-cancelable operating leases where Piedmont is the lessor as of September 30, 2019 is presented below (in thousands):


Years ending December 31:
2019 ⁽¹⁾	$	98,831
2020	382,738
2021	373,740
2022	357,475
2023	323,709
Thereafter	1,433,272
Total	$	2,969,765

⁽¹⁾Reflects rental payments for the fiscal period October 1, 2019 through December 31, 2019.


Years ending December 31:
2019	$	370,495
2020	352,541
2021	337,951
2022	324,960
2023	291,603
Thereafter	1,247,649
Total	$	2,925,199


	Three Months Ended		Nine Months Ended
	September 30, 2019		September 30, 2019
Fixed payments	$	105,207	$	311,503
Variable payments	25,372		70,710
Total Rental and Tenant Reimbursement Revenue	$	130,579	$	382,213

Stock Compensation to Non-employees

Reclassifications

Other Recent Accounting Pronouncements

Risk Management Objective of Using Derivatives

- Definition

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

+ References + Details

Summary of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Schedule of Future Minimum Rent Income

Piedmont's future minimum lease payments from lessees under non-cancelable operating leases where Piedmont is the lessor as of September 30, 2019 is presented below (in thousands):


Years ending December 31:
2019 ⁽¹⁾	$	98,831
2020	382,738
2021	373,740
2022	357,475
2023	323,709
Thereafter	1,433,272
Total	$	2,969,765

⁽¹⁾Reflects rental payments for the fiscal period October 1, 2019 through December 31, 2019.

Schedule of Future Minimum Rental Income


Years ending December 31:
2019	$	370,495
2020	352,541
2021	337,951
2022	324,960
2023	291,603
Thereafter	1,247,649
Total	$	2,925,199

Fixed and Variable Lease Revenue


	Three Months Ended		Nine Months Ended
	September 30, 2019		September 30, 2019
Fixed payments	$	105,207	$	311,503
Variable payments	25,372		70,710
Total Rental and Tenant Reimbursement Revenue	$	130,579	$	382,213

Debt (Tables)

9 Months Ended

Sep. 30, 2019

Debt Disclosure [Abstract]

Schedule of Debt

The following table summarizes the terms of Piedmont’s indebtedness outstanding as of September 30, 2019 and December 31, 2018 (in thousands):


Facility ⁽¹⁾	Stated Rate		Effective Rate ⁽²⁾			Maturity		Amount Outstanding as of
												September 30, 2019	December 31, 2018
Secured (Fixed)







$35 Million Fixed-Rate Loan ⁽³⁾	5.55	%	3.75	%		9/1/2021		$	29,033	$	29,706
$160 Million Fixed-Rate Loan ⁽⁴⁾	3.48	%	3.58	%		7/5/2022		160,000		160,000
Net premium and unamortized debt issuance costs								418		645
Subtotal/Weighted Average ⁽⁵⁾	3.80	%						189,451		190,351
Unsecured (Variable and Fixed)





Amended and Restated $300 Million Unsecured 2011 Term Loan	LIBOR + 1.00%		3.20	%	⁽⁷⁾	11/30/2021		300,000		300,000
$500 Million Unsecured 2018 Line of Credit ⁽⁶⁾	LIBOR + 0.90%		2.95	%		9/30/2022	⁽⁸⁾	398,000		205,000
$350 Million Unsecured Senior Notes	3.40	%	3.43	%		6/01/2023		350,000		350,000
$400 Million Unsecured Senior Notes	4.45	%	4.10	%		3/15/2024		400,000		400,000
$250 Million Unsecured 2018 Term Loan	LIBOR + 1.60%		3.93	%	⁽⁹⁾	3/31/2025		250,000		250,000
Discounts and unamortized debt issuance costs								(8,207)		(9,879)
Subtotal/Weighted Average ⁽⁵⁾	3.58	%						1,689,793		1,495,121
Total/Weighted Average ⁽⁵⁾	3.61	%						$	1,879,244	$	1,685,472

⁽¹⁾Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of September 30, 2019 and December 31, 2018 is interest-only until maturity.

⁽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 September 30, 2019.

Derivative Instruments (Tables)

9 Months Ended

Sep. 30, 2019

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 September 30, 2019 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

Amended and Restated $300 Million Unsecured 2011 Term Loan

300

11/22/2016

1/15/2020

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

100

3/29/2018

3/31/2025

Interest rate swaps

$250 Million Unsecured 2018 Term Loan

3/29/2018

3/29/2020

Total

450

Schedule of Interest Rate Derivatives

A detail of Piedmont’s interest rate derivatives on a gross and net basis as of September 30, 2019 and December 31, 2018, respectively, is as follows (in thousands):


Interest rate swaps classified as:	September 30, 2019		December 31, 2018
Gross derivative assets	$	—	$	1,199
Gross derivative liabilities	(6,862)		(839)
Net derivative asset/(liability)	$	(6,862)	$	360

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


	Three Months Ended						Nine Months Ended
Interest Rate Swaps in Cash Flow Hedging Relationships	September 30, 2019		September 30, 2018		September 30, 2019		September 30, 2018
Amount of gain/(loss) recognized in OCI	$	(1,386)	$	1,144	$	(6,874)	$	4,408
Amount of previously recorded gain reclassified from OCI into Interest Expense	$	427	$	434	$	1,871	$	885
Amount of 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	$	(16,145)	$	(15,849)	$	(46,750)	$	(45,294)
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.

Stock Based Compensation (Tables)

9 Months Ended

Sep. 30, 2019

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 nine months ended September 30, 2019 is as follows:


	Shares		Weighted-Average Grant Date Fair Value
Unvested and Potential Stock Awards as of December 31, 2018	1,227,483		$	23.14
Deferred Stock Awards Granted	354,057		$	21.02
Increase in Estimated Potential Share Award based on Performance	260,205		$	28.31
Performance Stock Awards Vested	(352,404)	⁽¹⁾	$	25.83
Deferred Stock Awards Vested	(440,450)	⁽¹⁾	$	19.66
Deferred Stock Awards Forfeited	(14,518)		$	19.16
Unvested and Potential Stock Awards as of September 30, 2019	1,034,373		$	25.10

⁽¹⁾Includes performance share and deferred stock awards that were settled in cash in July 2019 in conjunction with the senior management transition that occurred on June 30, 2019.


	Three Months Ended						Nine Months Ended
	September 30, 2019		September 30, 2018		September 30, 2019		September 30, 2018
Weighted-Average Grant Date Fair Value of Deferred Stock Granted During the Period	$	—	$	—	$	21.02	$	17.84
Total Grant Date Fair Value of Deferred Stock Vested During the Period	$	—	$	16	$	8,658	$	6,378
Share-based Liability Awards Paid During the Period (1)	$	3,444	$	—	$	6,683	$	2,947

Schedule of Outstanding Employee Stock Awards

A detail of Piedmont’s outstanding stock awards as of September 30, 2019 is as follows:


Date of grant	Type of Award	Net Shares Granted ⁽¹⁾	Grant Date Fair Value		Vesting Schedule	Unvested Shares
















May 18, 2017	Deferred Stock Award	196,036	$	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.	40,942
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.	153,368	⁽²⁾

May 17, 2018	Deferred Stock Award	271,169	$	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.	108,255
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.	200,674	⁽²⁾
May 15, 2019	Deferred Stock Award-Board of Directors	25,974	$	20.79	Of the shares granted, 100% will vest by May 15, 2020.	25,974
May 3, 2019	Deferred Stock Award	300,825	$	21.04	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 3, 2020, 2021, and 2022, respectively.	195,119
May 3, 2019	Fiscal Year 2019-2021 Performance Share Program	—	$	29.43	Shares awarded, if any, will vest immediately upon determination of award in 2022.	310,041	⁽²⁾
Total						1,034,373

Guarantor and Non-Guarantor Financial Information (Tables)

9 Months Ended

Sep. 30, 2019

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Condensed Consolidating Balance Sheets


Condensed Consolidating Balance Sheets
As of September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Assets:
Real estate assets, at cost:
Land	$	—	$	36,094	$	470,346	$	—	$	506,440
Buildings and improvements, less accumulated depreciation	—		186,269		2,141,086		(300)		2,327,055
Intangible lease assets, less accumulated amortization	—		—		88,371		—		88,371
Construction in progress	—		1,058		12,808		—		13,866
Real estate assets held for sale, net	—		—		213,094		—		213,094
Total real estate assets	—		223,421		2,925,705		(300)		3,148,826

Cash and cash equivalents	150		5,758		4,376		—		10,284
Tenant and straight-line rent receivables	—		16,514		140,774		—		157,288
Investment in subsidiaries	1,681,492		3,037,093		162		(4,718,747)		—
Notes receivable	—		810		144,500		(145,310)		—
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	35		6,227		22,710		(9)		28,963
Goodwill	—		98,918		—		—		98,918


Deferred lease costs, net	—		16,567		251,049		—		267,616
Other assets held for sale, net			—		40,036		—		40,036
Total assets	$	1,681,677	$	3,405,308	$	3,529,312	$	(4,864,366)	$	3,751,931
Liabilities:
Debt, net	$	—	$	1,689,749	$	334,805	$	(145,310)	$	1,879,244
Accounts payable, accrued expenses, and accrued capital expenditures	894		16,054		97,873		(9)		114,812
Deferred income	—		3,693		24,292		—		27,985
Intangible lease liabilities, net	—		—		34,970		—		34,970
Interest rate swaps	—		6,862		—		—		6,862
Liabilities held for sale	—		—		7,275		—		7,275
Total liabilities	894		1,716,358		499,215		(145,319)		2,071,148
Equity:
Total stockholders’ equity	1,680,783		1,688,950		3,030,097		(4,719,047)		1,680,783
Total liabilities and stockholders’ equity	$	1,681,677	$	3,405,308	$	3,529,312	$	(4,864,366)	$	3,751,931


Condensed Consolidating Balance Sheets
As of December 31, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Assets:
Real estate assets, at cost:
Land	$	—	$	36,094	$	434,338	$	—	$	470,432
Buildings and improvements, less accumulated depreciation	—		176,927		1,944,943		(300)		2,121,570
Intangible lease assets, less accumulated amortization	—		—		77,676		—		77,676
Construction in progress	—		5,708		10,140		—		15,848
Real estate assets held for sale, net	—		—		331,068		—		331,068
Total real estate assets	—		218,729		2,798,165		(300)		3,016,594

Cash and cash equivalents	150		—		4,939		(518)		4,571
Tenant and straight-line rent receivables	—		16,143		131,419		—		147,562

Investment in subsidiaries	1,744,122		2,704,337		166		(4,448,625)		—
Notes receivable	—		810		144,500		(145,310)		—
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	42		5,682		21,653		(24)		27,353
Goodwill	—		98,918		—		—		98,918


Deferred lease costs, net	—		15,158		221,040		—		236,198
Other assets held for sale, net	—		—		61,233		—		61,233
Total assets	$	1,744,314	$	3,059,777	$	3,383,115	$	(4,594,777)	$	3,592,429
Liabilities:
Debt, net	$	—	$	1,495,065	$	335,717	$	(145,310)	$	1,685,472
Accounts payable, accrued expenses, dividends payable, interest rate swaps and accrued capital expenditures	32,174		15,382		74,536		(542)		121,550

Deferred income	—		2,274		26,505		—		28,779
Intangible lease liabilities, net	—		—		35,708		—		35,708

Liabilities held for sale	—		—		8,780		—		8,780
Total liabilities	32,174		1,512,721		481,246		(145,852)		1,880,289
Equity:
Total stockholders’ equity	1,712,140		1,547,056		2,901,869		(4,448,925)		1,712,140
Total liabilities and stockholders’ equity	$	1,744,314	$	3,059,777	$	3,383,115	$	(4,594,777)	$	3,592,429

Consolidating Statements of Income


Consolidating Statements of Income
For the Three Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	11,940	$	119,385	$	(746)	$	130,579
Property management fee revenue	—		—		4,622		(4,217)		405
Other property related income	—		40		4,397		—		4,437
	—		11,980		128,404		(4,963)		135,421
Expenses:
Property operating costs	36		5,507		54,033		(4,963)		54,613
Depreciation	—		3,062		24,069		—		27,131
Amortization	—		486		19,019		—		19,505
Impairment loss on real estate assets	—		—		1,953		—		1,953
General and administrative	(30)		1,547		6,433		—		7,950
	6		10,602		105,507		(4,963)		111,152

Other income (expense):
Interest expense	—		(14,429)		(3,610)		1,894		(16,145)
Other income/(expense)	—		16		2,141		(1,894)		263




Gain on sale of real estate assets	—		—		32		—		32






Income/(loss) before consolidated subsidiaries	(6)		(13,035)		21,460		—		8,419
Income from subsidiaries	8,428		22,929		—		(31,357)		—
Net income	8,422		9,894		21,460		(31,357)		8,419
Plus: Net loss applicable to noncontrolling interest	—		—		3		—		3
Net income applicable to Piedmont	$	8,422	$	9,894	$	21,463	$	(31,357)	$	8,422

Consolidating Statements of Income



Consolidating Statements of Income
For the Three Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	10,861	$	114,351	$	(694)	$	124,518
Property management fee revenue	—		—		4,296		(3,928)		368
Other property related income	—		35		4,787		—		4,822
	—		10,896		123,434		(4,622)		129,708
Expenses:
Property operating costs	—		4,973		49,328		(4,622)		49,679
Depreciation	—		2,816		24,036		—		26,852
Amortization	—		446		14,394		—		14,840

General and administrative	42		1,424		5,211		—		6,677
	42		9,659		92,969		(4,622)		98,048

Other income (expense):
Interest expense	—		(14,119)		(3,624)		1,894		(15,849)
Other income/(expense)	—		40		2,157		(1,894)		303




	—		(14,079)		(1,467)		—		(15,546)
Income/(loss) before consolidated subsidiaries	(42)		(12,842)		28,998		—		16,114





Income from subsidiaries	16,156		26,787		—		(42,943)		—
Net income	16,114		13,945		28,998		(42,943)		16,114
Plus: Net loss applicable to noncontrolling interest	—		—		—		—		—
Net income applicable to Piedmont	$	16,114	$	13,945	$	28,998	$	(42,943)	$	16,114

Consolidating Statements of Income


Consolidating Statements of Income
For the Nine Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	34,477	$	349,886	$	(2,150)	$	382,213
Property management fee revenue	—		—		14,961		(12,142)		2,819
Other property related income	—		117		13,876		—		13,993
	—		34,594		378,723		(14,292)		399,025
Expenses:
Property operating costs	36		15,848		157,206		(14,292)		158,798
Depreciation	—		9,041		70,963		—		80,004
Amortization	—		1,435		54,231		—		55,666
Impairment loss on real estate assets	—		—		1,953		—		1,953
General and administrative	165		4,874		24,697		—		29,736
	201		31,198		309,050		(14,292)		326,157

Other income (expense):
Interest expense	—		(41,590)		(10,801)		5,641		(46,750)
Other income/(expense)	—		125		6,808		(5,641)		1,292



Gain on sale of real estate assets	—		128		39,242		—		39,370

	—		(41,337)		35,249		—		(6,088)
Income/(loss) before consolidated subsidiaries	(201)		(37,941)		104,922		—		66,780





Income from subsidiaries	66,984		72,012		—		(138,996)		—
Net income	66,783		34,071		104,922		(138,996)		66,780
Plus: Net loss applicable to noncontrolling interest	—		—		3		—		3
Net income applicable to Piedmont	$	66,783	$	34,071	$	104,925	$	(138,996)	$	66,783


Consolidating Statements of Income
For the Nine Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Revenues:


Rental and tenant reimbursement revenue	$	—	$	33,754	$	340,539	$	(1,802)	$	372,491
Property management fee revenue	—		—		12,625		(11,566)		1,059
Other property related income	—		92		15,140		—		15,232
	—		33,846		368,304		(13,368)		388,782
Expenses:
Property operating costs	—		14,614		152,929		(13,368)		154,175
Depreciation	—		8,527		72,585		—		81,112
Amortization	—		1,520		45,298		—		46,818

General and administrative	228		4,849		16,410		—		21,487
	228		29,510		287,222		(13,368)		303,592

Other income (expense):
Interest expense	—		(40,093)		(10,937)		5,736		(45,294)
Other income/(expense)	—		200		7,016		(5,736)		1,480



Loss on extinguishment of debt	—		(1,680)		—		—		(1,680)
Gain on sale of real estate assets	—		1,417		43,769		—		45,186
	—		(40,156)		39,848		—		(308)
Income/(loss) before consolidated subsidiaries	(228)		(35,820)		120,930		—		84,882





Income from subsidiaries	85,114		119,013		—		(204,127)		—
Net income	84,886		83,193		120,930		(204,127)		84,882

Plus: Net loss applicable to noncontrolling interest	—		—		4		—		4
Net income applicable to Piedmont	$	84,886	$	83,193	$	120,934	$	(204,127)	$	84,886

Consolidating Statements of Comprehensive Income


Consolidating Statements of Comprehensive Income
For the Three Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	8,422	$	9,894	$	21,463	$	(31,357)	$	8,422
Other comprehensive loss:
Effective portion of loss on derivative instruments that are designated and qualify as cash flow hedges	(1,386)		(1,386)		—		1,386		(1,386)
Less: Reclassification of net gain included in net income	(427)		(427)		—		427		(427)
Other comprehensive loss	(1,813)		(1,813)		—		1,813		(1,813)

Comprehensive income	$	6,609	$	8,081	$	21,463	$	(29,544)	$	6,609


Consolidating Statements of Comprehensive Income
For the Three Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	16,114	$	13,945	$	28,998	$	(42,943)	$	16,114
Other comprehensive income:
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	1,144		1,144		—		(1,144)		1,144
Less: Reclassification of net gain included in net income	(434)		(434)		—		434		(434)
Other comprehensive income	710		710		—		(710)		710

Comprehensive income	$	16,824	$	14,655	$	28,998	$	(43,653)	$	16,824

Consolidating Statements of Comprehensive Income


Consolidating Statements of Comprehensive Income
For the Nine Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	66,783	$	34,071	$	104,925	$	(138,996)	$	66,783
Other comprehensive loss:
Effective portion of loss on derivative instruments that are designated and qualify as cash flow hedges	(6,874)		(6,874)		—		6,874		(6,874)
Less: Reclassification of net gain included in net income	(1,871)		(1,871)		—		1,871		(1,871)
Other comprehensive loss	(8,745)		(8,745)		—		8,745		(8,745)

Comprehensive income	$	58,038	$	25,326	$	104,925	$	(130,251)	$	58,038


Consolidating Statements of Comprehensive Income
For the Nine Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net income	$	84,886	$	83,193	$	120,934	$	(204,127)	$	84,886
Other comprehensive income:
Effective portion of gain on derivative instruments that are designated and qualify as cash flow hedges	4,408		4,408		—		(4,408)		4,408
Plus: Reclassification of net loss included in net income	373		373		—		(373)		373
Other comprehensive income	4,781		4,781		—		(4,781)		4,781

Comprehensive income	$	89,667	$	87,974	$	120,934	$	(208,908)	$	89,667

Condensed Consolidating Statements of Cash Flows


Condensed Consolidating Statements of Cash Flows
For the Nine Months Ended September 30, 2019

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net Cash Provided by Operating Activities	$	72,694	$	43,676	$	182,344	$	(138,471)	$	160,243

Cash Flows from Investing Activities:
Investment in real estate assets and intangibles	—		(13,561)		(369,951)		—		(383,512)


Net sales proceeds from wholly-owned properties	—		128		180,847		—		180,975



Deferred lease costs paid	—		(1,210)		(15,422)		—		(16,632)
Distributions from subsidiaries	54,151		215,231		—		(269,382)		—
Net cash provided by/(used in) investing activities	54,151		200,588		(204,526)		(269,382)		(219,169)
Cash Flows from Financing Activities:
Debt issuance and other costs paid	—		(91)		—		—		(91)
Proceeds from debt	—		550,000		—		—		550,000
Repayments of debt	—		(357,000)		(1,041)		—		(358,041)


Costs of issuance of common stock	(259)		—		—		—		(259)
Value of shares withheld to pay tax obligations related to employee stock compensation	(3,295)		—		—		—		(3,295)
Repurchases of common stock as part of announced plan	(16,899)		—		—		—		(16,899)

Distributions	(106,392)		(431,416)		23,018		408,371		(106,419)
Net cash provided by/(used in) financing activities	(126,845)		(238,507)		21,977		408,371		64,996
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—		5,757		(205)		518		6,070
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150		32		6,370		(518)		6,034
Cash, cash equivalents, and restricted cash and escrows, end of period	$	150	$	5,789	$	6,165	$	—	$	12,104


Condensed Consolidating Statements of Cash Flows
For the Nine Months Ended September 30, 2018

(in thousands)	Piedmont (Parent) (Guarantor)		Piedmont OP (the Issuer)		Non-Guarantors		Eliminations		Consolidated
Net Cash Provided by Operating Activities	$	89,540	$	89,639	$	164,063	$	(204,920)	$	138,322

Cash Flows from Investing Activities:
Investment in real estate assets and intangibles	—		(6,074)		(67,100)		—		(73,174)
Intercompany note receivable	—		88,000		—		(88,000)		—



Net sales proceeds from wholly-owned properties	—		36,572		382,982		—		419,554


Note receivable issuance	—		—		(3,200)		—		(3,200)
Deferred lease costs paid	—		(1,826)		(14,005)		—		(15,831)
Distributions from subsidiaries	362,784		64,633		—		(427,417)		—
Net cash provided by investing activities	362,784		181,305		298,677		(515,417)		327,349
Cash Flows from Financing Activities:
Debt issuance costs paid	—		(947)		—		—		(947)
Proceeds from debt	—		820,061		—		—		820,061
Repayments of debt	—		(832,000)		(1,005)		—		(833,005)

Intercompany note payable	—		—		(88,000)		88,000		—

Value of shares withheld to pay tax obligations related to employee stock compensation	(2,219)		—		—		—		(2,219)
Repurchases of common stock as part of announced plan	(266,062)		—		—		—		(266,062)

Distributions	(184,043)		(258,907)		(373,460)		632,337		(184,073)
Net cash used in financing activities	(452,324)		(271,793)		(462,465)		720,337		(466,245)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	—		(849)		275		—		(574)
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	$	3,057	$	4,974	$	—	$	8,181

Organization (Details) ft² in Thousands	9 Months Ended
Organization (Details) ft² in Thousands	Sep. 30, 2019 ft² property asset subsidiary segment market
Real Estate Properties [Line Items]
Number of wholly-owned subsidiaries \| subsidiary	2
Percentage ownership by sole general partner	99.90%
Percentage ownership by sole limited partner	0.10%
Number of redevelopment assets \| asset	1
Number of operating segments \| segment	1
U.S.
Real Estate Properties [Line Items]
Number of major U.S. office markets \| market	7
In Service Office Properties
Real Estate Properties [Line Items]
Number of real estate properties \| property	55
Area of real estate property (in sq ft)	17,000
Percentage leased	91.90%
Redevelopment Asset
Real Estate Properties [Line Items]
Area of real estate property (in sq ft)	487

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Jan. 01, 2019
Concentration Risk [Line Items]
Weighted-average lease term of right-of-use assets				2 years
Right of use assets weighted-average discount rate	3.35%			3.35%
Rental and tenant reimbursement revenue	$ 130,579	$ 504,400	$ 124,518	$ 382,213	$ 372,491	$ 553,300
Fixed payments	105,207			311,503
Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Right of use asset							$ 200
Lease liability							$ 200
Operating lease costs	18			55
Reclassification Adjustment \| Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Reclassification out of rental income		411,700	101,300		304,300	455,100
Reclassification out of tenant reimbursement		$ 92,700	23,200		68,200	$ 98,200
Rental and Tenant Reimbursement Revenue \| Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Uncollectible accounts expense	$ 65			$ 24
Property Operating Costs \| Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Uncollectible accounts expense			$ 0		$ 84

Summary of Significant Accounting Policies (Schedule of Future Minimum Rental Income) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
2019	$ 98,831
2020	382,738
2021	373,740
2022	357,475
2023	323,709
Thereafter	1,433,272
Total	$ 2,969,765
2019		$ 370,495
2020		352,541
2021		337,951
2022		324,960
2023		291,603
Thereafter		1,247,649
Total		$ 2,925,199

Summary of Significant Accounting Policies (Schedule of Fixed and Variable Lease Payments) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Fixed payments	$ 105,207			$ 311,503
Variable payments	25,372			70,710
Total Rental and Tenant Reimbursement Revenue	$ 130,579	$ 504,400	$ 124,518	$ 382,213	$ 372,491	$ 553,300

Acquisitions (Details)	Aug. 23, 2019 USD ($) ft²	May 06, 2019 USD ($) ft²	Sep. 30, 2019 USD ($) a property
Property, Plant and Equipment [Line Items]
Number of properties acquired \| property			3
Area of land acquired (in acres) \| a			11.7
$500 Million Unsecured 2018 Line of Credit \| Unsecured Debt
Property, Plant and Equipment [Line Items]
Face amount of debt instrument			$ 500,000,000
Galleria 100
Property, Plant and Equipment [Line Items]
Ownership percentage acquired		100.00%
Rentable square feet (in sq ft) \| ft²		414,293
Percentage leased		91.00%
Net contractual purchase price		$ 95,100,000
Galleria 400 and 600
Property, Plant and Equipment [Line Items]
Ownership percentage acquired	100.00%
Rentable square feet (in sq ft) \| ft²	863,623
Percentage leased	84.00%
Net contractual purchase price	$ 231,200,000

Debt (Schedule of Debt) (Details)	9 Months Ended
Debt (Schedule of Debt) (Details)	Sep. 30, 2019 USD ($) extension	Dec. 31, 2018 USD ($)
Debt Instrument [Line Items]
Weighted average rate (percent)	3.61%
Amount outstanding	$ 1,879,244,000	$ 1,685,472,000
Interest rate swaps
Debt Instrument [Line Items]
Notional amount of interest rate swap agreements	450,000,000
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 (percent)	3.80%
Amount outstanding	$ 189,451,000	190,351,000
Discounts and unamortized debt issuance costs	$ (418,000)	(645,000)
Secured Debt \| $35 Million Fixed-Rate Loan
Debt Instrument [Line Items]
Stated rate (percent)	5.55%
Effective interest rate (percent)	3.75%
Amount outstanding	$ 29,033,000	29,706,000
Face amount of debt instrument	$ 35,000,000	35,000,000
Secured Debt \| $160 Million Fixed Rate Loan
Debt Instrument [Line Items]
Stated rate (percent)	3.48%
Effective interest rate (percent)	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 (percent)	3.58%
Amount outstanding	$ 1,689,793,000	1,495,121,000
Discounts and unamortized debt issuance costs	(8,207,000)	(9,879,000)
Unsecured Debt \| Amended and Restated $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 \| Amended and Restated $300 Million Unsecured 2011 Term Loan \| Interest rate swaps
Debt Instrument [Line Items]
Effective interest rate (percent)	3.20%
Unsecured Debt \| Amended and Restated $300 Million Unsecured 2011 Term Loan \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.00%
Unsecured Debt \| $500 Million Unsecured 2018 Line of Credit
Debt Instrument [Line Items]
Face amount of debt instrument	$ 500,000,000
Unsecured Debt \| $500 Million Unsecured 2018 Line of Credit \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.90%
Unsecured Debt \| $500 Million Unsecured 2018 Line of Credit \| Line of Credit
Debt Instrument [Line Items]
Effective interest rate (percent)	2.95%
Amount outstanding	$ 398,000,000	205,000,000
Maximum extension period (in years)	1 year
Number of extension periods \| extension	2
Extension period (in months)	6 months
Unsecured Debt \| $350 Million Unsecured Senior Notes
Debt Instrument [Line Items]
Stated rate (percent)	3.40%
Effective interest rate (percent)	3.43%
Amount outstanding	$ 350,000,000	350,000,000
Face amount of debt instrument	$ 350,000,000
Unsecured Debt \| $400 Million Unsecured Senior Notes
Debt Instrument [Line Items]
Stated rate (percent)	4.45%
Effective interest rate (percent)	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 (percent)	3.93%
Amount outstanding	$ 250,000,000	$ 250,000,000
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 (percent)	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%

Derivative Instruments (Details)	3 Months Ended		9 Months Ended
Derivative Instruments (Details)	Sep. 30, 2019 USD ($) contract	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) contract	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Derivative [Line Items]
Maximum period of extension term			66 months
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Gross derivative assets	$ 0		$ 0		$ 1,199,000
Gross derivative liabilities	(6,862,000)		(6,862,000)		(839,000)
Net derivative asset/(liability)	(6,862,000)		(6,862,000)		$ 360,000
Amount of gain/(loss) recognized in OCI	(1,386,000)	$ 1,144,000	(6,874,000)	$ 4,408,000
Total amount of Interest Expense presented in the consolidated statements of income	(16,145,000)	(15,849,000)	(46,750,000)	(45,294,000)
Total amount of Loss on Extinguishment of Debt presented in the consolidated statements of income	0	0	0	(1,680,000)
Loss on write off of discount and unamortized debt issuance costs			400,000
Gain (loss) to be reclassified	200,000		200,000
Gain (loss) from hedge ineffectiveness	0	0	0	0
Assets needed for immediate settlement, aggregate fair value	7,100,000		7,100,000
Interest rate swaps
Derivative [Line Items]
Total notional amount	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	(16,145,000)	(15,849,000)	(46,750,000)	(45,294,000)
Interest rate swaps \| Interest Expense
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Amount of gain/(loss) recognized in OCI	(1,386,000)	1,144,000	(6,874,000)	4,408,000
Amount of gain/(loss) reclassified from OCI	427,000	434,000	1,871,000	885,000
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	0	$ (1,258,000)
Unsecured Debt \| Amended and Restated $300 Million Unsecured 2011 Term Loan
Derivative [Line Items]
Face amount of debt instrument	$ 300,000,000		$ 300,000,000
Unsecured Debt \| Amended and Restated $300 Million Unsecured 2011 Term Loan \| Interest rate swaps
Derivative [Line Items]
Number of Swap Agreements \| contract	3		3
Total notional amount	$ 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	$ 150,000,000		$ 150,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan \| Interest rate swaps
Derivative [Line Items]
Number of Swap Agreements \| contract	2		2
Total notional amount	$ 100,000,000		$ 100,000,000
Unsecured Debt \| $250 Million Unsecured 2018 Term Loan Maturing 2020 \| Interest rate swaps
Derivative [Line Items]
Number of Swap Agreements \| contract	1		1
Total notional amount	$ 50,000,000		$ 50,000,000

Fair Value Measurement of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	$ 0	$ 1,199
Interest rate swaps	6,862	839
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10,284	4,571
Restricted cash and escrows	1,820	1,463
Accounts payable and accrued expenses	14,090	47,328
Debt, net	1,879,244	1,685,472
Tenant receivables, net \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	10,091	10,800
Level 1 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	10,284	4,571
Restricted cash and escrows	1,820	1,463
Accounts payable and accrued expenses	14,090	47,328
Level 1 \| Tenant receivables, net \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Tenant receivables, net	10,091	10,800
Level 2 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, net	1,922,891	1,698,213
Interest rate swaps \| Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	0	1,199
Interest rate swaps	6,862	839
Interest rate swaps \| Level 2 \| Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	0	1,199
Interest rate swaps	$ 6,862	$ 839

Assets Held for Sale (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total other assets held for sale, net	$ 40,036	$ 61,233
Accrued expenses	7,275	8,780
Disposal Group, Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated depreciation (building improvements)	(61,579)	(102,476)
Total real estate assets held for sale, net	213,094	331,068
Straight-line rent receivables	26,132	36,584
Prepaid expenses and other assets	452	1,095
Deferred lease costs, less accumulated amortization of $7,887 and $9,138 as of September 30, 2019 and December 31, 2018, respectively	13,452	23,554
Accumulated amortization on deferred lease costs	(7,887)	(9,138)
Total other assets held for sale, net	40,036	61,233
Accrued expenses	7,275	8,780
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:	36,990	67,552
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:	176,066	261,463
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:	$ 38	$ 2,053

Stock Based Compensation (Rollforward of Stock Awards) (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Shares
Increase in estimated potential share award based on performance (in shares)			260,205
Unvested and potential stock awards, end of period (in shares)	1,034,373		1,034,373
Weighted-Average Grant Date Fair Value
Increase in estimated potential share award (in dollars per share)			$ 28.31
Stock Awards
Shares
Unvested and potential stock awards, beginning of period (in shares)			1,227,483
Unvested and potential stock awards, end of period (in shares)	1,034,373		1,034,373
Weighted-Average Grant Date Fair Value
Unvested and potential stock awards, beginning of period (in dollars per share)			$ 23.14
Unvested and potential stock awards, end of period (in dollars per share)	$ 25.10		$ 25.10
Deferred Stock Awards
Shares
Deferred stock awards granted (in shares)			354,057
Stock awards vested (in shares)			(440,450)
Deferred stock awards forfeited (in shares)			(14,518)
Weighted-Average Grant Date Fair Value
Deferred stock awards granted (in dollars per share)	$ 0	$ 0	$ 21.02	$ 17.84
Stock awards vested (in dollars per share)			19.66
Deferred stock awards forfeited (in dollars per share)			$ 19.16
Performance Share Awards
Shares
Stock awards vested (in shares)			(352,404)
Weighted-Average Grant Date Fair Value
Stock awards vested (in dollars per share)			$ 25.83

Stock Based Compensation (Additional Information Regarding Stock Award Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Deferred Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred stock awards granted (in dollars per share)	$ 0	$ 0	$ 21.02	$ 17.84
Weighted-average grant date fair value of deferred stock granted during the period	$ 0	$ 16	$ 8,658	$ 6,378
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Liability Awards Paid During the Period	$ 3,444	$ 0	$ 6,683	$ 2,947

Stock Based Compensation (Outstanding Employee Stock Awards) (Details) - $ / shares	May 15, 2019	May 03, 2019	May 17, 2018	May 18, 2017	Sep. 30, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested shares (in shares)					1,034,373
Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant date fair value (in dollars per share)					$ 25.10	$ 23.14
Unvested shares (in shares)					1,034,373	1,227,483
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)				196,036
Grant date fair value (in dollars per share)				$ 21.38
Unvested shares (in shares)					40,942
Deferred Stock Awards \| Deferred Stock Award, Granted May 18, 2017 \| Year 1
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 \| Year 2
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 \| Year 3
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 \| Year 4
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 Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)			271,169
Grant date fair value (in dollars per share)			$ 17.84
Unvested shares (in shares)					108,255
Deferred Stock Awards \| Deferred Stock Award, Granted May 17, 2018 \| Year 1
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 \| Year 2
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 \| Year 3
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 \| Year 4
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage			25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 15,2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)	25,974
Grant date fair value (in dollars per share)	$ 20.79
Unvested shares (in shares)					25,974
Deferred Stock Awards \| Deferred Stock Award, Granted May 15,2019 \| 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 3, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted (in shares)		300,825
Grant date fair value (in dollars per share)		$ 21.04
Unvested shares (in shares)					195,119
Deferred Stock Awards \| Deferred Stock Award, Granted May 3, 2019 \| Year 1
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 3, 2019 \| Year 2
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 3, 2019 \| Year 3
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
Deferred Stock Awards \| Deferred Stock Award, Granted May 3, 2019 \| Year 4
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percentage		25.00%
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)					153,368
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)					200,674
Performance Share Awards \| Performance Share Program Award, Granted May 3, 2019
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)		$ 29.43
Unvested shares (in shares)					310,041

Stock Based Compensation (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense related to stock awards	$ 3.8	$ 1.7	$ 12.0	$ 6.7
Amortization of unvested shares			$ 10.5	$ 5.6
Total shares issued to employees, directors, and officers (in shares)			292,675
Unrecognized compensation cost related to nonvested	$ 4.5		$ 4.5
Weighted Average
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to nonvested, weighted-average vesting period			1 year

Supplemental Disclosures for the Statement of Consolidated Cash Flows (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Accrued capital expenditures and deferred lease costs	$ 29,828	$ 21,784
Change in accrued dividends and discount on dividend reinvestments	(26,972)	(101,794)
Change in accrued share repurchases as part of an announced plan	(4,417)	(1,277)
Accrued stock issuance costs	441	0
Cash and cash equivalents	10,284	6,807	$ 4,571	$ 7,382
Restricted cash and escrows	1,820	1,374	1,463	1,373
Total cash, cash equivalents, and restricted cash and escrows shown in the consolidated statement of cash flows	$ 12,104	$ 8,181	$ 6,034	$ 8,755

Earnings Per Share (Details) - shares	3 Months Ended		9 Months Ended
Earnings Per Share (Details) - shares	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Anti-dilutive shares excluded (in shares)	251	0	54,372	125,941
Weighted-average common shares – basic (in shares)	125,783,408	128,371,062	125,684,202	130,837,223
Plus: Incremental weighted-average shares from time-vested deferred and performance stock awards (in shares)	457,000	448,000	506,000	350,000
Weighted-average common shares – diluted (in shares)	126,239,744	128,818,658	126,189,851	131,187,127

Guarantor and Non-Guarantor Financial Information (Balance Sheets) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Assets:
Land	$ 506,440			$ 470,432
Buildings and improvements, less accumulated depreciation	2,327,055			2,121,570
Intangible lease assets, less accumulated amortization	88,371			77,676
Construction in progress	13,866			15,848
Real estate assets held for sale, net	213,094			331,068
Total real estate assets	3,148,826			3,016,594
Cash and cash equivalents	10,284			4,571	$ 6,807			$ 7,382
Tenant and straight-line rent receivables	157,288			147,562
Investment in subsidiaries	0			0
Notes receivable	0			0
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	28,963			27,353
Goodwill	98,918			98,918
Deferred lease costs, net	267,616			236,198
Other assets held for sale, net	40,036			61,233
Total assets	3,751,931			3,592,429
Liabilities:
Debt, net	1,879,244			1,685,472
Accounts payable, accrued expenses, interest rate swaps and accrued capital expenditures	114,812			121,550
Deferred income	27,985			28,779
Intangible lease liabilities, net	34,970			35,708
Interest rate swaps	6,862			839
Other liabilities held for sale	7,275			8,780
Total liabilities	2,071,148			1,880,289
Equity:
Total stockholders’ equity	1,680,783	$ 1,702,975	$ 1,723,522	1,712,140	$ 1,733,996	$ 1,743,056	$ 1,789,588	$ 1,986,489
Total liabilities and stockholders’ equity	3,751,931			3,592,429
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			0
Total real estate assets	(300)			(300)
Cash and cash equivalents	0			(518)
Tenant and straight-line rent receivables	0			0
Investment in subsidiaries	(4,718,747)			(4,448,625)
Notes receivable	(145,310)			(145,310)
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	(9)			(24)
Goodwill	0			0
Deferred lease costs, net	0			0
Other assets held for sale, net	0			0
Total assets	(4,864,366)			(4,594,777)
Liabilities:
Debt, net	(145,310)			(145,310)
Accounts payable, accrued expenses, interest rate swaps and accrued capital expenditures	(9)			(542)
Deferred income	0			0
Intangible lease liabilities, net	0			0
Interest rate swaps	0
Other liabilities held for sale	0			0
Total liabilities	(145,319)			(145,852)
Equity:
Total stockholders’ equity	(4,719,047)			(4,448,925)
Total liabilities and stockholders’ equity	(4,864,366)			(4,594,777)
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			0
Total real estate assets	0			0
Cash and cash equivalents	150			150
Tenant and straight-line rent receivables	0			0
Investment in subsidiaries	1,681,492			1,744,122
Notes receivable	0			0
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	35			42
Goodwill	0			0
Deferred lease costs, net	0			0
Other assets held for sale, net				0
Total assets	1,681,677			1,744,314
Liabilities:
Debt, net	0			0
Accounts payable, accrued expenses, interest rate swaps and accrued capital expenditures	894			32,174
Deferred income	0			0
Intangible lease liabilities, net	0			0
Interest rate swaps	0
Other liabilities held for sale	0			0
Total liabilities	894			32,174
Equity:
Total stockholders’ equity	1,680,783			1,712,140
Total liabilities and stockholders’ equity	1,681,677			1,744,314
Piedmont OP (the Issuer) \| Reportable Legal Entities
Assets:
Land	36,094			36,094
Buildings and improvements, less accumulated depreciation	186,269			176,927
Intangible lease assets, less accumulated amortization	0			0
Construction in progress	1,058			5,708
Real estate assets held for sale, net	0			0
Total real estate assets	223,421			218,729
Cash and cash equivalents	5,758			0
Tenant and straight-line rent receivables	16,514			16,143
Investment in subsidiaries	3,037,093			2,704,337
Notes receivable	810			810
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	6,227			5,682
Goodwill	98,918			98,918
Deferred lease costs, net	16,567			15,158
Other assets held for sale, net	0			0
Total assets	3,405,308			3,059,777
Liabilities:
Debt, net	1,689,749			1,495,065
Accounts payable, accrued expenses, interest rate swaps and accrued capital expenditures	16,054			15,382
Deferred income	3,693			2,274
Intangible lease liabilities, net	0			0
Interest rate swaps	6,862
Other liabilities held for sale	0			0
Total liabilities	1,716,358			1,512,721
Equity:
Total stockholders’ equity	1,688,950			1,547,056
Total liabilities and stockholders’ equity	3,405,308			3,059,777
Non-Guarantors \| Reportable Legal Entities
Assets:
Land	470,346			434,338
Buildings and improvements, less accumulated depreciation	2,141,086			1,944,943
Intangible lease assets, less accumulated amortization	88,371			77,676
Construction in progress	12,808			10,140
Real estate assets held for sale, net	213,094			331,068
Total real estate assets	2,925,705			2,798,165
Cash and cash equivalents	4,376			4,939
Tenant and straight-line rent receivables	140,774			131,419
Investment in subsidiaries	162			166
Notes receivable	144,500			144,500
Prepaid expenses, restricted cash, escrows, interest rate swaps, and other assets	22,710			21,653
Goodwill	0			0
Deferred lease costs, net	251,049			221,040
Other assets held for sale, net	40,036			61,233
Total assets	3,529,312			3,383,115
Liabilities:
Debt, net	334,805			335,717
Accounts payable, accrued expenses, interest rate swaps and accrued capital expenditures	97,873			74,536
Deferred income	24,292			26,505
Intangible lease liabilities, net	34,970			35,708
Interest rate swaps	0
Other liabilities held for sale	7,275			8,780
Total liabilities	499,215			481,246
Equity:
Total stockholders’ equity	3,030,097			2,901,869
Total liabilities and stockholders’ equity	$ 3,529,312			$ 3,383,115

Guarantor and Non-Guarantor Financial Information (Income) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017
Revenues:
Rental and tenant reimbursement revenue	$ 130,579		$ 504,400	$ 124,518			$ 382,213	$ 372,491	$ 553,300
Total revenues	135,421			129,708			399,025	388,782
Expenses:
Property operating costs	54,613			49,679			158,798	154,175
Depreciation	27,131			26,852			80,004	81,112
Amortization	19,505			14,840			55,666	46,818
Impairment loss on real estate assets	1,953			0			1,953	0
General and administrative	7,950			6,677			29,736	21,487
Operating expenses	111,152			98,048			326,157	303,592
Other income (expense):
Interest expense	(16,145)			(15,849)			(46,750)	(45,294)
Other income/(expense)	263			303			1,292	1,480
Loss on extinguishment of debt	0			0			0	(1,680)
Gain on sale of real estate assets	32			0			39,370	45,186
Nonoperating income (expense	(15,850)			(15,546)			(6,088)	(308)
Income/(loss) before consolidated subsidiaries	8,419			16,114			66,780	84,882
Income from subsidiaries	0			0			0	0
Net income	8,419			16,114			66,780	84,882
Net loss applicable to noncontrolling interest	3	$ 1	(1)	0	$ 2	$ 2	3	4
Net income applicable to Piedmont	8,422	$ 8,153	$ 50,208	16,114	$ 10,942	$ 57,830	66,783	84,886
Eliminations
Revenues:
Rental and tenant reimbursement revenue	(746)			(694)			(2,150)	(1,802)
Total revenues	(4,963)			(4,622)			(14,292)	(13,368)
Expenses:
Property operating costs	(4,963)			(4,622)			(14,292)	(13,368)
Depreciation	0			0			0	0
Amortization	0			0			0	0
Impairment loss on real estate assets	0						0
General and administrative	0			0			0	0
Operating expenses	(4,963)			(4,622)			(14,292)	(13,368)
Other income (expense):
Interest expense	1,894			1,894			5,641	5,736
Other income/(expense)	(1,894)			(1,894)			(5,641)	(5,736)
Loss on extinguishment of debt								0
Gain on sale of real estate assets	0						0	0
Nonoperating income (expense				0			0	0
Income/(loss) before consolidated subsidiaries	0			0			0	0
Income from subsidiaries	(31,357)			(42,943)			(138,996)	(204,127)
Net income	(31,357)			(42,943)			(138,996)	(204,127)
Net loss applicable to noncontrolling interest	0			0			0	0
Net income applicable to Piedmont	(31,357)			(42,943)			(138,996)	(204,127)
Piedmont (Parent) (Guarantor) \| Reportable Legal Entities
Revenues:
Rental and tenant reimbursement revenue	0			0			0	0
Total revenues	0			0			0	0
Expenses:
Property operating costs	36			0			36	0
Depreciation	0			0			0	0
Amortization	0			0			0	0
Impairment loss on real estate assets	0						0
General and administrative	(30)			42			165	228
Operating expenses	6			42			201	228
Other income (expense):
Interest expense	0			0			0	0
Other income/(expense)	0			0			0	0
Loss on extinguishment of debt								0
Gain on sale of real estate assets	0						0	0
Nonoperating income (expense				0			0	0
Income/(loss) before consolidated subsidiaries	(6)			(42)			(201)	(228)
Income from subsidiaries	8,428			16,156			66,984	85,114
Net income	8,422			16,114			66,783	84,886
Net loss applicable to noncontrolling interest	0			0			0	0
Net income applicable to Piedmont	8,422			16,114			66,783	84,886
Piedmont OP (the Issuer) \| Reportable Legal Entities
Revenues:
Rental and tenant reimbursement revenue	11,940			10,861			34,477	33,754
Total revenues	11,980			10,896			34,594	33,846
Expenses:
Property operating costs	5,507			4,973			15,848	14,614
Depreciation	3,062			2,816			9,041	8,527
Amortization	486			446			1,435	1,520
Impairment loss on real estate assets	0						0
General and administrative	1,547			1,424			4,874	4,849
Operating expenses	10,602			9,659			31,198	29,510
Other income (expense):
Interest expense	(14,429)			(14,119)			(41,590)	(40,093)
Other income/(expense)	16			40			125	200
Loss on extinguishment of debt								(1,680)
Gain on sale of real estate assets	0						128	1,417
Nonoperating income (expense				(14,079)			(41,337)	(40,156)
Income/(loss) before consolidated subsidiaries	(13,035)			(12,842)			(37,941)	(35,820)
Income from subsidiaries	22,929			26,787			72,012	119,013
Net income	9,894			13,945			34,071	83,193
Net loss applicable to noncontrolling interest	0			0			0	0
Net income applicable to Piedmont	9,894			13,945			34,071	83,193
Non-Guarantors \| Reportable Legal Entities
Revenues:
Rental and tenant reimbursement revenue	119,385			114,351			349,886	340,539
Total revenues	128,404			123,434			378,723	368,304
Expenses:
Property operating costs	54,033			49,328			157,206	152,929
Depreciation	24,069			24,036			70,963	72,585
Amortization	19,019			14,394			54,231	45,298
Impairment loss on real estate assets	1,953						1,953
General and administrative	6,433			5,211			24,697	16,410
Operating expenses	105,507			92,969			309,050	287,222
Other income (expense):
Interest expense	(3,610)			(3,624)			(10,801)	(10,937)
Other income/(expense)	2,141			2,157			6,808	7,016
Loss on extinguishment of debt								0
Gain on sale of real estate assets	32						39,242	43,769
Nonoperating income (expense				(1,467)			35,249	39,848
Income/(loss) before consolidated subsidiaries	21,460			28,998			104,922	120,930
Income from subsidiaries	0			0			0	0
Net income	21,460			28,998			104,922	120,930
Net loss applicable to noncontrolling interest	3			0			3	4
Net income applicable to Piedmont	21,463			28,998			104,925	120,934
Property management fee revenue
Revenues:
Property management and other property related revenue	405			368			2,819	1,059
Property management fee revenue \| Eliminations
Revenues:
Property management and other property related revenue	(4,217)			(3,928)			(12,142)	(11,566)
Property management fee revenue \| Piedmont (Parent) (Guarantor) \| Reportable Legal Entities
Revenues:
Property management and other property related revenue	0			0			0	0
Property management fee revenue \| Piedmont OP (the Issuer) \| Reportable Legal Entities
Revenues:
Property management and other property related revenue	0			0			0	0
Property management fee revenue \| Non-Guarantors \| Reportable Legal Entities
Revenues:
Property management and other property related revenue	4,622			4,296			14,961	12,625
Other property related income
Revenues:
Property management and other property related revenue	4,437			4,822			13,993	15,232
Other property related income \| Eliminations
Revenues:
Property management and other property related revenue	0			0			0	0
Other property related income \| Piedmont (Parent) (Guarantor) \| Reportable Legal Entities
Revenues:
Property management and other property related revenue	0			0			0	0
Other property related income \| Piedmont OP (the Issuer) \| Reportable Legal Entities
Revenues:
Property management and other property related revenue	40			35			117	92
Other property related income \| Non-Guarantors \| Reportable Legal Entities
Revenues:
Property management and other property related revenue	$ 4,397			$ 4,787			$ 13,876	$ 15,140

Guarantor and Non-Guarantor Financial Information (Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	$ 8,422	$ 8,153	$ 50,208	$ 16,114	$ 10,942	$ 57,830	$ 66,783	$ 84,886
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	(1,386)			1,144			(6,874)	4,408
Plus: Reclassification of gain included in net income	(427)			(434)			(1,871)	373
Other comprehensive income/(loss)	(1,813)	$ (4,137)	$ (2,795)	710	$ 1,502	$ 2,569	(8,745)	4,781
Comprehensive income applicable to Piedmont	6,609			16,824			58,038	89,667
Reportable Legal Entities \| Piedmont (Parent) (Guarantor)
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	8,422			16,114			66,783	84,886
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	(1,386)			1,144			(6,874)	4,408
Plus: Reclassification of gain included in net income	(427)			(434)			(1,871)	373
Other comprehensive income/(loss)	(1,813)			710			(8,745)	4,781
Comprehensive income applicable to Piedmont	6,609			16,824			58,038	89,667
Reportable Legal Entities \| Piedmont OP (the Issuer)
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	9,894			13,945			34,071	83,193
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	(1,386)			1,144			(6,874)	4,408
Plus: Reclassification of gain included in net income	(427)			(434)			(1,871)	373
Other comprehensive income/(loss)	(1,813)			710			(8,745)	4,781
Comprehensive income applicable to Piedmont	8,081			14,655			25,326	87,974
Reportable Legal Entities \| Non-Guarantors
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	21,463			28,998			104,925	120,934
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	0			0			0	0
Plus: Reclassification of gain included in net income	0			0			0	0
Other comprehensive income/(loss)	0			0			0	0
Comprehensive income applicable to Piedmont	21,463			28,998			104,925	120,934
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net income applicable to Piedmont	(31,357)			(42,943)			(138,996)	(204,127)
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	1,386			(1,144)			6,874	(4,408)
Plus: Reclassification of gain included in net income	427			434			1,871	(373)
Other comprehensive income/(loss)	1,813			(710)			8,745	(4,781)
Comprehensive income applicable to Piedmont	$ (29,544)			$ (43,653)			$ (130,251)	$ (208,908)

Guarantor and Non-Guarantor Financial Information (Cash Flows) (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 160,243,000	$ 138,322,000
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles	(383,512,000)	(73,174,000)
Intercompany note receivable		0
Net sales proceeds from wholly-owned properties	180,975,000	419,554,000
Note receivable issuance	0	(3,200,000)
Deferred lease costs paid	(16,632,000)	(15,831,000)
Distributions from subsidiaries	0	0
Net cash (used in)/provided by investing activities	(219,169,000)	327,349,000
Cash Flows from Financing Activities:
Debt issuance and other costs paid	(91,000)	(947,000)
Proceeds from debt	550,000,000	820,061,000
Repayments of debt	(358,041,000)	(833,005,000)
Costs of issuance of common stock	(259,000)	0
Intercompany note payable		0
Value of shares withheld to pay tax obligations related to employee stock compensation	(3,295,000)	(2,219,000)
Repurchases of common stock as part of announced plan	(16,899,000)	(266,062,000)
Distributions	(106,419,000)	(184,073,000)
Net cash provided by/(used in) financing activities	64,996,000	(466,245,000)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	6,070,000	(574,000)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	6,034,000	8,755,000
Cash, cash equivalents, and restricted cash and escrows, end of period	12,104,000	8,181,000
Eliminations
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	(138,471,000)	(204,920,000)
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles	0	0
Intercompany note receivable		(88,000,000)
Net sales proceeds from wholly-owned properties	0	0
Note receivable issuance		0
Deferred lease costs paid	0	0
Distributions from subsidiaries	(269,382,000)	(427,417,000)
Net cash (used in)/provided by investing activities	(269,382,000)	(515,417,000)
Cash Flows from Financing Activities:
Debt issuance and other costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Costs of issuance of common stock	0
Intercompany note payable		88,000,000
Value of shares withheld to pay tax obligations related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0	0
Distributions	408,371,000	632,337,000
Net cash provided by/(used in) financing activities	408,371,000	720,337,000
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	518,000	0
Cash, cash equivalents, and restricted cash and escrows, beginning of period	(518,000)	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	72,694,000	89,540,000
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles	0	0
Intercompany note receivable		0
Net sales proceeds from wholly-owned properties	0	0
Note receivable issuance		0
Deferred lease costs paid	0	0
Distributions from subsidiaries	54,151,000	362,784,000
Net cash (used in)/provided by investing activities	54,151,000	362,784,000
Cash Flows from Financing Activities:
Debt issuance and other costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Costs of issuance of common stock	(259,000)
Intercompany note payable		0
Value of shares withheld to pay tax obligations related to employee stock compensation	(3,295,000)	(2,219,000)
Repurchases of common stock as part of announced plan	(16,899,000)	(266,062,000)
Distributions	(106,392,000)	(184,043,000)
Net cash provided by/(used in) financing activities	(126,845,000)	(452,324,000)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	0	0
Cash, cash equivalents, and restricted cash and escrows, beginning of period	150,000	150,000
Cash, cash equivalents, and restricted cash and escrows, end of period	150,000	150,000
Piedmont OP (the Issuer) \| Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	43,676,000	89,639,000
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles	(13,561,000)	(6,074,000)
Intercompany note receivable		88,000,000
Net sales proceeds from wholly-owned properties	128,000	36,572,000
Note receivable issuance		0
Deferred lease costs paid	(1,210,000)	(1,826,000)
Distributions from subsidiaries	215,231,000	64,633,000
Net cash (used in)/provided by investing activities	200,588,000	181,305,000
Cash Flows from Financing Activities:
Debt issuance and other costs paid	(91,000)	(947,000)
Proceeds from debt	550,000,000	820,061,000
Repayments of debt	(357,000,000)	(832,000,000)
Costs of issuance of common stock	0
Intercompany note payable		0
Value of shares withheld to pay tax obligations related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0	0
Distributions	(431,416,000)	(258,907,000)
Net cash provided by/(used in) financing activities	(238,507,000)	(271,793,000)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	5,757,000	(849,000)
Cash, cash equivalents, and restricted cash and escrows, beginning of period	32,000	3,906,000
Cash, cash equivalents, and restricted cash and escrows, end of period	5,789,000	3,057,000
Non-Guarantors \| Reportable Legal Entities
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	182,344,000	164,063,000
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles	(369,951,000)	(67,100,000)
Intercompany note receivable		0
Net sales proceeds from wholly-owned properties	180,847,000	382,982,000
Note receivable issuance		(3,200,000)
Deferred lease costs paid	(15,422,000)	(14,005,000)
Distributions from subsidiaries	0	0
Net cash (used in)/provided by investing activities	(204,526,000)	298,677,000
Cash Flows from Financing Activities:
Debt issuance and other costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	(1,041,000)	(1,005,000)
Costs of issuance of common stock	0
Intercompany note payable		(88,000,000)
Value of shares withheld to pay tax obligations related to employee stock compensation	0	0
Repurchases of common stock as part of announced plan	0	0
Distributions	23,018,000	(373,460,000)
Net cash provided by/(used in) financing activities	21,977,000	(462,465,000)
Net increase/(decrease) in cash, cash equivalents, and restricted cash and escrows	(205,000)	275,000
Cash, cash equivalents, and restricted cash and escrows, beginning of period	6,370,000	4,699,000
Cash, cash equivalents, and restricted cash and escrows, end of period	$ 6,165,000	$ 4,974,000

Subsequent Events (Details) $ / shares in Units, ft² in Thousands, $ in Thousands			9 Months Ended
	Oct. 30, 2019 $ / shares	Oct. 28, 2019 USD ($) ft² $ / ft²	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)
Subsequent Event [Line Items]
Net sales proceeds from wholly-owned properties			$ 180,975	$ 419,554
Subsequent Event
Subsequent Event [Line Items]
Common stock dividends (in dollars per share) \| $ / shares	$ 0.21
Subsequent Event \| West Monroe Street
Subsequent Event [Line Items]
Net sales proceeds from wholly-owned properties		$ 412,000
Proceeds from sale of real estate assets \| $ / ft²		(426)
Area of real estate property (in sq ft) \| ft²		967
Leased percentage of real estate asset		100.00%

Impairment Loss on Real Estate Assets	9 Months Ended
Impairment Loss on Real Estate Assets	Sep. 30, 2019
Real Estate [Abstract]
Impairment Loss on Real Estate Assets	Impairment Loss on Real Estate AssetsDuring the three months ended September 30, 2019, Piedmont reduced The Dupree building's carrying value to reflect its fair value, estimated based on the net contract price of $12.7 million, and recognized an impairment loss on real estate assets of approximately $2.0 million. Piedmont closed on the sale of The Dupree building on September 4, 2019.

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments Under Existing Lease Agreements As a recurring part of its business, Piedmont is typically required under its executed lease agreements to fund 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. As of September 30, 2019, Piedmont had no individually significant unrecorded tenant allowance commitments. 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 different interpretations of language in the lease agreements from that made by Piedmont, which could result in requests for refunds of previously recognized tenant reimbursement revenues, resulting in financial loss to Piedmont. Piedmont recorded net recoveries of previously recognized reductions in rental and reimbursement revenues of $0.7 million related to tenant audits/disputes during the three and nine months ended September 30, 2019 and approximately $0.1 million and $0.5 million of reductions in rental and reimbursement revenues related to such tenant audits/disputes during the three and nine months ended September 30, 2018, respectively.

Related Party Transactions	9 Months Ended
Related Party Transactions	Sep. 30, 2019
Related Party Transactions [Abstract]
Related Party Transactions	Related-Party TransactionsDuring the nine months ended September 30, 2019, Piedmont entered into employment or retirement agreements with certain of its current and former executive officers as more fully described in its Definitive Proxy Statement and Current Report on Form 8-K filed on March 19, 2019. There were no other related-party transactions during the nine months ended September 30, 2019.

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events Fourth Quarter Dividend Declaration On October 30, 2019, the Board of Directors of Piedmont declared a dividend for the fourth quarter of 2019 in the amount of $0.21 per common share outstanding to stockholders of record as of the close of business on November 29, 2019. Such dividend will be paid on January 3, 2020. Disposition Activity On October 28, 2019, Piedmont closed on the sale of the 500 West Monroe Street building with an unrelated third party for $412 million ($426 per square foot). The 500 West Monroe Street building, an approximately 967,000 square foot office building, is 100% leased.

Debt (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
Debt (Narrative) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Debt Disclosure [Abstract]
Interest paid	$ 17.8	$ 18.0	$ 49.7	$ 48.7
Interest costs capitalized	$ 0.5	$ 0.4	$ 1.6	$ 0.8

Label	Element	Value
AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (94,000)
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 94,000