Piedmont Office Realty Trust (PDM) 10-Q 29 Apr 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 28, 2015
Document and Entity Information [Abstract]
Entity Registrant Name	Piedmont Office Realty Trust, Inc.
Entity Central Index Key	1042776
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Amendment Flag	FALSE
Entity Common Stock, Shares Outstanding		154,391,509

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets:
Land	$707,340	$702,800
Buildings and improvements, less accumulated depreciation of $1,118,327 and $1,088,062 as of March 31, 2015 and December 31, 2014, respectively	3,234,495	3,224,178
Intangible lease assets, less accumulated amortization of $84,212 and $79,860 as of March 31, 2015 and December 31, 2014, respectively	69,254	70,177
Construction in progress	83,853	63,393
Real estate assets held for sale	0	14,544
Total real estate assets	4,094,942	4,075,092
Investments in and amounts due from unconsolidated joint ventures	7,820	7,798
Cash and cash equivalents	7,479	12,306
Tenant receivables, net of allowance for doubtful accounts of $106 and $231 as of March 31, 2015 and December 31, 2014, respectively	30,132	27,711
Straight-line rent receivables	175,340	169,532
Restricted cash and escrows	671	5,679
Prepaid expenses and other assets	26,879	27,820
Goodwill	180,097	180,097
Interest rate swaps	520	430
Deferred financing costs, less accumulated amortization of $6,607 and $6,067 as of March 31, 2015 and December 31, 2014, respectively	7,391	7,667
Deferred lease costs, less accumulated amortization of $152,161 and $142,915 as of March 31, 2015 and December 31, 2014, respectively	288,591	280,105
Other assets held for sale	0	1,264
Total assets	4,819,862	4,795,501
Liabilities:
Unsecured debt, net of discount of $5,682 and $5,456 as of March 31, 2015 and December 31, 2014, respectively	1,877,318	1,828,544
Secured debt, inclusive of premium of $3,137 and $3,258 as of March 31, 2015 and December 31, 2014, respectively	448,791	449,045
Accounts payable, accrued expenses, and accrued capital expenditures	119,466	133,988
Deferred income	25,970	22,215
Intangible lease liabilities, less accumulated amortization of $39,682 and $37,964 as of March 31, 2015 and December 31, 2014, respectively	42,978	43,277
Interest rate swaps	19,416	6,417
Total liabilities	2,533,939	2,483,486
Commitments and Contingencies	0	0
Stockholders’ Equity:
Shares-in-trust, 150,000,000 shares authorized; none outstanding as of March 31, 2015 or December 31, 2014	0	0
Preferred stock, no par value, 100,000,000 shares authorized; none outstanding as of March 31, 2015 or December 31, 2014	0	0
Common stock, $.01 par value, 750,000,000 shares authorized; 154,339,507 and 154,324,089 shares issued and outstanding as of March 31, 2015 and December 31, 2014, respectively	1,543	1,543
Additional paid-in capital	3,667,574	3,666,182
Cumulative distributions in excess of earnings	-1,378,786	-1,365,620
Other comprehensive income	-5,437	8,301
Piedmont stockholders’ equity	2,284,894	2,310,406
Noncontrolling interest	1,029	1,609
Total stockholders’ equity	2,285,923	2,312,015
Total liabilities and stockholders’ equity	$4,819,862	$4,795,501

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Assets:
Intangible lease assets, accumulated amortization	$84,212	$79,860
Tenant receivables, allowance for doubtful accounts	106	231
Deferred financing costs, accumulated amortization	6,607	6,067
Deferred lease costs, accumulated amortization	152,161	142,915
Liabilities:
Unsecured debt- discount on debt	5,682	5,456
Secured debt- premium on debt	3,137	3,258
Intangible lease liabilities, accumulated amortization	39,682	37,964
Stockholders’ Equity:
Shares-in-trust, shares authorized	150,000,000	150,000,000
Shares-in-trust, shares outstanding	0	0
Preferred stock, par value (in dollars per share)	$0	$0
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$0.01	$0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	154,339,507	154,324,089
Common stock, shares outstanding	154,339,507	154,324,089
Building and Building Improvements [Member]
Assets:
Buildings and improvements, accumulated depreciation	$1,118,327	$1,088,062

Consolidated_Statements_of_Inc

Consolidated Statements of Income (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues:
Rental income	$117,807	$110,904
Tenant reimbursements	31,390	24,929
Property management fee revenue	562	487
Total revenues	149,759	136,320
Expenses:
Property operating costs	64,236	58,271
Depreciation	36,232	33,644
Amortization	14,670	14,573
General and administrative	6,407	4,555
Operating Expenses	121,545	111,043
Real estate operating income	28,214	25,277
Other income (expense):
Interest expense	-19,016	-18,926
Other income/(expense)	-181	-90
Net recoveries from casualty events and litigation settlements	0	3,042
Equity in income/(loss) of unconsolidated joint ventures	159	-266
Nonoperating Income (Expense)	-19,038	-16,240
Income from continuing operations	9,176	9,037
Discontinued operations:
Operating income	0	466
Loss on sale of real estate assets, net	0	-106
Income from discontinued operations	0	360
Gain on sale of real estate assets, net	10,073	0
Net income	19,249	9,397
Less: Net income attributable to noncontrolling interest	-4	-4
Net income attributable to Piedmont	$19,245	$9,393
Per share information – basic and diluted:
Income from continuing operations and gain on sale of real estate assets (in dollars per share)	$0.12	$0.06
Income from discontinued operations (in dollars per share)	$0	$0
Net income available to common stockholders (in dollars per share)	$0.12	$0.06
Weighted-average common shares outstanding – basic	154,339,029	154,849,378
Weighted-average common shares outstanding – diluted	154,580,335	155,024,545

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income attributable to Piedmont	$19,245	$9,393
Other comprehensive income/(loss):
Effective portion of gain/(loss) on derivative instruments that are designated and qualify as cash flow hedges (See Note 5)	-15,205	-9,886
Reclassification of previously recorded loss included in net income (See Note 5)	1,467	1,170
Other comprehensive income/(loss)	-13,738	-8,716
Comprehensive income attributable to Piedmont	$5,507	$677

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Cumulative Distributions in Excess of Earnings [Member]	Other Comprehensive Loss [Member]	Non-controlling Interest [Member]
In Thousands, except Share data, unless otherwise specified
Balance at Dec. 31, 2013	$2,461,159	$1,575	$3,668,906	($1,231,209)	$20,278	$1,609
Balance (in shares) at Dec. 31, 2013		157,461,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	-52,796	-32		-52,764
Share repurchases as part of an announced plan, shares		-3,190,000
Retirement of shares returned from escrow	-1,479	-1	-1,478
Retirement of shares returned from escrow, shares		-85,000
Redemption of noncontrolling interest in consolidated variable interest entity	-4,054		-4,054
Dividends to common stockholders ($0.81 (YTD 2014) and $0.21 (YTD 2015) per share), distributions to noncontrolling interest, and dividends reinvested	-125,198		-188	-124,995		-15
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	2,997	1	2,996
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		138,000
Net income attributable to noncontrolling interest	15					15
Net income attributable to Piedmont	43,348			43,348
Other comprehensive income (loss)	-11,977				-11,977
Balance at Dec. 31, 2014	2,312,015	1,543	3,666,182	-1,365,620	8,301	1,609
Balance (in shares) at Dec. 31, 2014	154,324,089	154,324,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share repurchases as part of an announced plan	0	0		0
Share repurchases as part of an announced plan, shares		0
Offering costs	-285		-285
Redemption of noncontrolling interest in consolidated variable interest entity	54		54
Reallocation of noncontrolling interest of subsidiary	544		1,128			-584
Dividends to common stockholders ($0.81 (YTD 2014) and $0.21 (YTD 2015) per share), distributions to noncontrolling interest, and dividends reinvested	-32,477		-66	-32,411
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax	561		561
Shares issued and amortized under the 2007 Omnibus Incentive Plan, net of tax (in shares)		16,000
Net income attributable to noncontrolling interest	4					4
Net income attributable to Piedmont	19,245			19,245
Other comprehensive income (loss)	-13,738				-13,738
Balance at Mar. 31, 2015	$2,285,923	$1,543	$3,667,574	($1,378,786)	($5,437)	$1,029
Balance (in shares) at Mar. 31, 2015	154,339,507	154,340,000

Consolidated_Statements_of_Sto1

Consolidated Statements of Stockholders' Equity (Parenthetical) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Dividends to common stockholders (in dollars per share)	$0.21	$0.81

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash Flows from Operating Activities:
Net income	$19,249	$9,397
Operating distributions received from unconsolidated joint ventures	137	266
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	36,232	33,727
Amortization of deferred financing costs	387	774
Settlement of forward starting interest rate swaps	0	14,960
Other amortization	14,806	14,346
Stock compensation expense	725	636
Equity in loss/(income) of unconsolidated joint ventures	-159	266
(Gain)/loss on sale of real estate assets, net	10,073	-106
Changes in assets and liabilities:
Increase in tenant and straight-line rent receivables, net	-11,234	-1,371
(Increase)/decrease in restricted cash and escrows	-148	43
Decrease/(increase) in prepaid expenses and other assets	1,037	-3,467
Decrease in accounts payable and accrued expenses	-11,074	-350
Increase in deferred income	3,745	720
Net cash provided by operating activities	43,630	70,053
Cash Flows from Investing Activities:
Acquisition of real estate assets and related intangibles	-41,554	-400
Capitalized expenditures, net of accruals	-39,804	-27,187
Redemption of noncontrolling interest in unconsolidated variable interest entity	-4,000	0
Net sales proceeds from wholly-owned properties	25,803	22,322
Deferred lease costs paid	-4,414	-4,180
Net cash used in investing activities	-63,969	-9,445
Cash Flows from Financing Activities:
Deferred financing costs paid	-242	-454
Proceeds from debt	257,575	764,564
Repayments of debt	-209,254	-737,000
Costs of issuance of common stock	-90	0
Repurchases of common stock as part of announced plan	0	-54,515
Dividends paid and discount on dividend reinvestments	-32,477	-30,905
Net cash provided by/(used in) financing activities	15,512	-58,310
Net (decrease)/increase in cash and cash equivalents	-4,827	2,298
Cash and cash equivalents, beginning of period	12,306	6,973
Cash and cash equivalents, end of period	7,479	9,271
Supplemental Disclosures of Significant Noncash Investing and Financing Activities:
Change in accrued share repurchases as part of an announced plan	0	-1,836
Accrued capital expenditures and deferred lease costs	$12,946	$13,721

Organization

Organization	3 Months Ended
	Mar. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization
	Piedmont Office Realty Trust, Inc. (“Piedmont”) (NYSE: PDM) is a Maryland corporation that operates in a manner so as to qualify as a real estate investment trust (“REIT”) for federal income tax purposes and engages in the acquisition, development, management, and ownership of commercial real estate properties throughout the United States, including properties that are under construction, are newly constructed, or have operating histories. Piedmont was incorporated in 1997 and commenced operations in 1998. Piedmont conducts business primarily through Piedmont Operating Partnership, L.P. (“Piedmont OP”), a Delaware limited partnership, as well as performing the management of its buildings through two wholly-owned subsidiaries, Piedmont Government Services, LLC and Piedmont Office Management, LLC. Piedmont owns 99.9% of, and is the sole general partner of, Piedmont OP and as such, possesses full legal control and authority over the operations of Piedmont OP. The remaining 0.1% ownership interest of Piedmont OP is held indirectly by Piedmont through its wholly-owned subsidiary, Piedmont Office Holdings, Inc. ("POH"), the sole limited partner of Piedmont OP. Piedmont OP owns properties directly, through wholly-owned subsidiaries, and through both consolidated and unconsolidated joint ventures. References to Piedmont herein shall include Piedmont and all of its subsidiaries, including Piedmont OP and its subsidiaries and joint ventures.
	As of March 31, 2015, Piedmont owned 74 office properties, one redevelopment asset, and one office building through an unconsolidated joint venture. Piedmont's 74 consolidated office properties comprise 21.5 million square feet of primarily Class A commercial office space, and were 88.8% leased as of March 31, 2015. As of March 31, 2015, approximately 90% of Piedmont's Annualized Lease Revenue was generated from select office sub-markets in the following cities: Atlanta, Boston, Chicago, Dallas, Houston, Los Angeles, Minneapolis, New York, and Washington, D.C.
	Piedmont internally evaluates all of its real estate assets as one operating segment, and accordingly, does not report segment information.

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies
	Basis of Presentation and Principles of Consolidation
	The consolidated financial statements of Piedmont have been prepared in accordance with the rules and regulations of the Securities and Exchange Commission (the “SEC”), including the instructions to Form 10-Q and Article 10 of Regulation S-X, and do not include all of the information and footnotes required by U.S. generally accepted accounting principles (“GAAP”) for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year’s results.
	Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity ("VIE") of which Piedmont or any of its wholly-owned subsidiaries is considered to have the power to direct the activities of the entity and the obligation to absorb losses/right to receive benefits, or any entity in which Piedmont or any of its wholly-owned subsidiaries owns a controlling interest. In determining whether Piedmont or Piedmont OP has a controlling interest, the following factors, among others, are considered: equity ownership, voting rights, protective rights of investors, and participatory rights of investors. For further information, refer to the financial statements and footnotes included in Piedmont’s Annual Report on Form 10-K for the year ended December 31, 2014.
	All inter-company balances and transactions have been eliminated upon consolidation.
	Further, Piedmont has formed special purpose entities to acquire and hold real estate. Each special purpose entity is a separate legal entity and consequently the assets of the special purpose entities are not available to all creditors of Piedmont. The assets owned by these special purpose entities are being reported on a consolidated basis with Piedmont’s assets for financial reporting purposes only.
	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 (the “Code”), and has operated as such, beginning with its taxable year ended December 31, 1998. To qualify as a REIT, Piedmont must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its annual REIT taxable income. As a REIT, Piedmont is generally not subject to federal income taxes. Piedmont is subject to certain taxes related to the operations of properties in certain locations, as well as operations conducted by its taxable REIT subsidiary, POH, which have been provided for in the financial statements.
	Recent Accounting Pronouncements
	The Financial Accounting Standards Board (the "FASB") has issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). The amendments in ASU 2014-09 change the criteria for the recognition of revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services using a five-step determination process. Steps 1 through 5 involve (i) identifying contracts with a customer, (ii) identifying the performance obligations in the contract, (iii) determining the transaction price, (iv) allocating the transaction price to the performance obligations, and (v) recognizing revenue as an entity satisfies a performance obligation. Additionally, lease contracts are specifically excluded from ASU 2014-09. The amendments in ASU 2014-09 are effective in the first quarter of 2017 for Piedmont, and early adoption is not permitted. Piedmont is currently evaluating the potential impact, if any, of adoption.
	The FASB has issued Accounting Standards Update No. 2015-02, Consolidation (Topic 810), Amendments to the Consolidation Analysis ("ASU 2015-02"). The amendments in ASU 2015-02 modifies the consolidation analysis of certain types of entities. Specifically, ASU 2015-02 changes the assessment criteria of whether limited partnerships are VIEs, eliminates the presumption that general partners should consolidate a limited partner, eliminates certain conditions from the evaluation of whether a fee paid to a decision maker constitutes a VIE, and changes the evaluation regarding the impact of related parties in the primary beneficiary determination of a VIE. The amendments in ASU 2015-02 are effective in the first quarter of 2016 for Piedmont, and Piedmont is currently evaluating the potential impact, if any, of adoption.
	The FASB has issued Accounting Standards Update No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30), Simplifying the Presentation of Debt Issuance Costs ("ASU 2015-03"). The amendments in ASU 2015-03 require debt issuance costs to be presented in the balance sheet as a reduction to the underlying debt instrument, as opposed to a separate asset. The amendments do not change the method by which such costs are amortized against earnings, nor do they change their classification in the consolidated statements of income, as a component of interest expense. The amendments in ASU 2015-03 are effective in the first quarter of 2016 for Piedmont, and Piedmont is currently evaluating the potential impact of adoption.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Acquisitions	Acquisitions
	During the three months ended March 31, 2015, Piedmont acquired 100% ownership of the following property using proceeds from the $500 Million Unsecured Line of Credit, proceeds from the sale of the 3900 Dallas Parkway building in Plano, Texas (see Note 9), and cash on hand, as noted below:
	Property	Metropolitan Statistical Area	Date of Acquisition	Rentable Square Feet	Percentage Leased as of Acquisition		Purchase Price
							(in millions)
	Park Place on Turtle Creek	Dallas, TX	January 16, 2015	177,844	88	%	$	46.6

Debt

Debt	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Debt	Debt
	During the three months ended March 31, 2015, Piedmont entered into a $170 million unsecured term loan facility (the “$170 Million Unsecured 2015 Term Loan”) with a consortium of lenders. The term of the $170 Million Unsecured 2015 Term Loan is approximately three years with a maturity date of May 15, 2018; however, Piedmont may prepay the $170 Million Unsecured 2015 Term Loan, in whole or in part, at any time without premium or penalty. The proceeds of the $170 Million Unsecured 2015 Term Loan were used to pay off the principal maturing on the $50 Million Unsecured Term Loan, and the remaining net proceeds were used to pay down the balance outstanding under the $500 Million Unsecured Line of Credit.
	The $170 Million Unsecured 2015 Term Loan has the option to bear interest at varying levels based on (i) the London Interbank Offered Rate (“LIBOR”) or Base Rate, defined as the greater of the prime rate, the federal funds rate plus one-half of one percent, or LIBOR for a one-month period plus one percent, (ii) the credit rating levels issued for the Registrant, and (iii) for LIBOR loans, an interest period selected by Piedmont OP of one, two, three, or six months, or to the extent available from all lenders in each case, one year or periods of less than one month. The stated interest rate spread over LIBOR can vary from 0.9% to 1.75% based upon the then current credit rating of Piedmont. As of March 31, 2015, the stated interest rate spread on the $170 Million Unsecured 2015 Term Loan was 1.125%.
	Under the $170 Million Unsecured 2015 Term Loan, Piedmont is subject to certain financial covenants that require, among other things, the maintenance of an unencumbered interest coverage ratio of at least 1.75, an unencumbered leverage ratio of at least 1.60, a fixed charge coverage ratio of at least 1.50, a leverage ratio of no more than 0.60, and a secured debt ratio of no more than 0.40. As of March 31, 2015, Piedmont believes it was in compliance with all financial covenants associated with its debt instruments.
	Additionally, during the three months ended March 31, 2015, Piedmont incurred additional working capital borrowings of $88.0 million and, utilizing a portion of the proceeds of the $170 Million Unsecured 2015 Term Loan described above, as well as other cash on hand, made repayments totaling $159.0 million on its $500 Million Unsecured Line of Credit. Piedmont also made interest payments on all debt facilities, including interest rate swap cash settlements, of approximately $20.4 million and $16.5 million for the three months ended March 31, 2015 and 2014, respectively. Piedmont capitalized interest of $0.8 million and $0.4 million for the three months ended March 31, 2015 and 2014, respectively.
	The following table summarizes the terms of Piedmont’s indebtedness outstanding as of March 31, 2015 and December 31, 2014 (in thousands):
	Facility		Collateral	Stated Rate(1)			Maturity		Amount Outstanding as of
									March 31,		December 31,
									2015		2014
	Secured (Fixed)
	$105 Million Fixed-Rate Loan		US Bancorp Center	5.29	%	(2)	5/11/15		$	105,000	$	105,000
	$125 Million Fixed-Rate Loan		Four Property Collateralized	5.5	%		4/1/16		125,000		125,000
			Pool (3)
	$42.5 Million Fixed-Rate Loan		Las Colinas Corporate	5.7	%		10/11/16		42,525		42,525
			Center I & II
	$140 Million WDC Fixed-Rate Loans		1201 & 1225 Eye Street	5.76	%		11/1/17		140,000		140,000
	$35 Million Fixed-Rate Loan		5 Wall Street	5.55	%	(4)	9/1/21		36,266		36,520
	Subtotal/Weighted Average (5)			5.56	%				448,791		449,045
	Unsecured (Variable and Fixed)
	$300 Million Unsecured 2011 Term Loan			LIBOR +  1.15%		(6)	1/15/20		298,996		298,944
	$500 Million Unsecured Line of Credit			LIBOR + 1.175%		(7)	8/19/16	(8)	363,000		434,000
	$350 Million Unsecured Senior Notes			3.4	%	(9)	6/1/23		348,831		348,800
	$300 Million Unsecured 2013 Term Loan			LIBOR + 1.20%		(10)	1/31/19		300,000		300,000
	$400 Million Unsecured Senior Notes			4.45	%	(11)	3/15/24		396,914		396,832
	$50 Million Unsecured Term Loan			LIBOR + 1.15%			4/1/15		—		49,968
	$170 Million Unsecured 2015 Term Loan			LIBOR + 1.125%		(12)	5/15/18		169,577		—
	Subtotal/Weighted Average (5)			2.78	%				1,877,318		1,828,544
	Total/ Weighted Average (5)			3.31	%				$	2,326,109	$	2,277,589
	(1)	Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of March 31, 2015 and December 31, 2014 is interest-only.
	(2)	On April 10, 2015, Piedmont repaid in full the balance on the $105 Million Fixed-Rate Loan.
	(3)	Property collateralized pool includes 1430 Enclave Parkway in Houston, Texas, Windy Point I and II in Schaumburg, Illinois, and 1055 East Colorado Boulevard in Pasadena, California.
	(4)	The $35 Million Fixed-Rate Loan has a contractual fixed rate of 5.55% ; however, the amortization of the premium recorded in order to adjust the note to its estimated fair value, results in an effective interest rate of 3.75%.
	(5)	Weighted average is based on contractual balance of outstanding debt and interest rates in the table as of March 31, 2015.
	(6)	The $300 Million Unsecured 2011 Term Loan 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, the rate on this facility to 2.39% through the original maturity date of November 22, 2016 and 3.35% from November 22, 2016 to January 15, 2020.
	(7)	Piedmont may select from multiple interest rate options with each draw, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.175% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of 30-day LIBOR draws at a rate of 0.18% (subject to the additional spread mentioned above).
	(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 August 21, 2017) provided Piedmont is not then in default and upon payment of extension fees.
	(9)	The $350 Million Senior Notes have a fixed coupon rate of 3.40%, however, as a result of the issuance of the notes at a discount, Piedmont recognizes an effective interest rate on this debt issuance of 3.45%. After consideration of the impact of settled interest rate swap agreements, in addition to the issuance discount, the effective interest rate on this debt is 3.43%.
	(10)	The $300 Million Unsecured 2013 Term Loan has a stated variable rate; however, Piedmont entered into interest rate swap agreements which effectively fix, absent any changes to Piedmont's credit rating, the rate on this facility to 2.78% .
	(11)	The $400 Million Senior Notes have a fixed coupon rate of 4.45%, however, as a result of the issuance of the notes at a discount, Piedmont recognizes an effective interest rate on this debt issuance of 4.48%. After consideration of the impact of settled interest rate swap agreements, in addition to the issuance discount, the effective interest rate on this debt is 4.10%.
	(12)	Piedmont may select from multiple interest rate options, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.125% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of a 30-day LIBOR draw at a rate of 0.18% (subject to the additional spread mentioned above).

Derivative_Instruments

Derivative Instruments	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments
	Risk Management Objective of Using Derivatives
	In addition to operational risks which arise in the normal course of business, Piedmont is exposed to economic risks such as interest rate, liquidity, and credit risk. In certain situations, Piedmont has entered into derivative financial instruments such as interest rate swap agreements and other similar agreements to manage interest rate risk exposure arising from current or future 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 changing the underlying notional amount. As of March 31, 2015, Piedmont was party to various forward starting interest rate swap agreements which fully hedge the variable cash flows associated with all of its outstanding unsecured, variable-rate debt, other than the $500 Million Line of Credit and the $170 Million Unsecured 2015 Term Loan. Additionally, as of March 31, 2015, Piedmont held $500 million of forward starting interest rate swaps to hedge its exposure to the variability in future cash flows associated with potential future debt issuances in 2015 and 2016. The maximum length of time over which Piedmont is hedging its exposure to the variability in future cash flows for forecasted transactions is 131 months.
	The detail of Piedmont’s interest rate derivatives outstanding as of March 31, 2015 is as follows:
	Interest Rate Derivatives:		Number of Swap Agreements		Associated Debt Instrument		Total Notional Amount		Effective Date	Maturity Date
							(in millions)
	Interest rate swaps		4		$300 Million Unsecured 2011 Term Loan		$	300	11/22/11	11/22/16
	Interest rate swaps		4		$300 Million Unsecured 2013 Term Loan		200		1/30/14	1/31/19
	Interest rate swaps		2		$300 Million Unsecured 2013 Term Loan		100		8/29/14	1/31/19
	Forward starting interest rate swaps		3		$300 Million Unsecured 2011 Term Loan		300		11/22/16	1/15/20
	Forward starting interest rate swaps		4		Potential Future Issuance		250		2/27/15	2/27/22
	Forward starting interest rate swaps		4		Potential Future Issuance		250		2/25/16	2/25/26
	Total						$	1,400
	Piedmont has elected to present its interest rate derivatives on its consolidated balance sheets on a gross basis as interest rate swap assets and interest rate swap liabilities. The detail of Piedmont’s interest rate derivatives on a gross and net basis as of March 31, 2015 and December 31, 2014, respectively, is as follows (in thousands):
	Interest rate swaps classified as:	March 31,				December 31,
		2015				2014
	Gross derivative assets	$	520			$	430
	Gross derivative liabilities	(19,416		)		(6,417		)
	Net derivative liability	$	(18,896	)		$	(5,987	)
	All of Piedmont's interest rate derivative agreements outstanding for the periods presented were designated as cash flow hedges of interest rate risk. As such, the effective portion of changes in the estimated fair value of these derivatives is recorded in other comprehensive income ("OCI") and is reclassified into earnings as interest expense in the period that the hedged forecasted transaction affects earnings. In addition, in conjunction with the issuance of various unsecured senior notes during the years ended December 31, 2014 and 2013, Piedmont settled several forward starting swap agreements for gains which were recorded as accumulated other comprehensive income during the respective period and are being amortized as an offset to interest expense over the term of the respective notes on a straight line basis (which approximates the effective interest method). Piedmont classifies cash flows from the settlement of hedging derivative instruments in the same category as the underlying exposure which is being hedged. As the settlements were the result of hedging Piedmont's exposure to interest rate changes and their effect on interest expense, they are classified as operating cash flows in the accompanying consolidated statements of cash flows.
	The effective portion of Piedmont's interest rate derivatives, including the gain on settlement of forward swaps described above, that was recorded in the accompanying consolidated statements of income for the three months ended March 31, 2015 and 2014, respectively, was as follows:
		Three Months Ended
	Derivative in	March 31,				March 31,
	Cash Flow Hedging	2015				2014
	Relationships (Interest Rate Swaps) (in thousands)
	Amount of gain/(loss) recognized in OCI on derivative	$	(15,205	)		$	(9,886	)
	Amount of previously recorded loss reclassified from accumulated OCI into interest expense	$	1,467			$	1,170
	Piedmont estimates that approximately $5.7 million will be reclassified from accumulated other comprehensive loss to interest expense over the next twelve months. No gain or loss was recognized related to hedge ineffectiveness or to amounts excluded from effectiveness testing on Piedmont’s cash flow hedges during the three months ended March 31, 2015 or 2014.
	See Note 7 for fair value disclosures of Piedmont's derivative instruments.
	Credit-risk-related Contingent Features
	Piedmont has agreements with its derivative counterparties that contain a provision whereby if Piedmont defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then Piedmont could also be declared in default on its derivative obligations. If Piedmont were to breach any of the contractual provisions of the derivative contracts, it would be required to settle its obligations under the agreements at their termination value of the estimated fair values plus accrued interest, or approximately $20.3 million as of March 31, 2015. 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.

Variable_Interest_Entities_and

Variable Interest Entities and Equity Participation Rights	3 Months Ended
	Mar. 31, 2015
Variable Interest Entities [Abstract]
Variable Interest Entities and Equity Participation Rights	Variable Interest Entities and Equity Participation Rights
	Variable interest holders who have the power to direct the activities of the VIE that most significantly impact the entity’s economic performance and have the obligation to absorb the majority of losses of the entity or the right to receive significant benefits of the entity must consolidate the VIE.
	During the three months ended March 31, 2015, Piedmont paid $4 million to settle the redemption option associated with an equity participation in Medici Atlanta, LLC, eliminating any ongoing third party interest.
	A summary of Piedmont’s interests in and consolidation treatment of its outstanding VIEs as of March 31, 2015 and their related carrying values as of December 31, 2014 is as follows (net carrying amount in millions):
	Entity	Piedmont’s	Related	Consolidated/	Net Carrying			Net Carrying			Primary Beneficiary
		%	Building	Unconsolidated	Amount as of			Amount as of			Considerations
		Ownership			31-Mar-15			December 31,
		of Entity						2014
	1201 Eye Street NW Associates, LLC	49.50%	1201 Eye Street	Consolidated	$	(2.5	)	$	(2.8	)	In accordance with the partnership’s governing documents, Piedmont is entitled to 100% of the cash flow of the entity until certain financial returns are achieved and has sole discretion in directing the management and leasing activities of the building.
	1225 Eye Street NW Associates, LLC	49.50%	1225 Eye Street	Consolidated	$	0.6		$	(1.1	)	In accordance with the partnership’s governing documents, Piedmont is entitled to 100% of the cash flow of the entity until certain financial returns are achieved and has sole discretion in directing the management and leasing activities of the building.
	Piedmont 500 W. Monroe Fee, LLC	100%	500 W. Monroe	Consolidated	$	245.7		$	245.3		The Omnibus Agreement with the previous owner includes equity participation rights for the previous owner, if certain financial returns are achieved; however, Piedmont has sole decision making authority and is entitled to the economic benefits of the property until such returns are met.
	Piedmont TownPark Land, LLC	100%	Land Parcel Adjacent to 400 TownPark building	Consolidated	$	7.9		$	7.9		The equity participation and service fee agreement includes equity participation rights for the third party manager if certain defined events occur and certain returns on investment are achieved; however, Piedmont has sole decision making authority and is entitled to the economic benefits of the property until such events occur and returns are achieved.
	Each of the VIEs described above has the sole purpose of holding land and office buildings and their resulting operations, and are classified in the accompanying consolidated balance sheets in the same manner as Piedmont’s wholly-owned properties.

Fair_Value_Measurement_of_Fina

Fair Value Measurement of Financial Instruments	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurement of Financial Instruments	Fair Value Measurement of Financial Instruments
	Piedmont considers its cash, tenant receivables, restricted cash and escrows, accounts payable and accrued expenses, interest rate swap agreements, and debt to meet the definition of financial instruments. The following table sets forth the carrying and estimated fair value for each of Piedmont’s financial instruments, as well as its level within the GAAP fair value hierarchy, as of March 31, 2015 and December 31, 2014, respectively (in thousands):
		March 31, 2015					December 31, 2014
	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)	$	7,479	$	7,479	Level 1	$	12,306	$	12,306	Level 1
	Tenant receivables, net(1)	$	30,132	$	30,132	Level 1	$	27,711	$	27,711	Level 1
	Restricted cash and escrows(1)	$	671	$	671	Level 1	$	5,679	$	5,679	Level 1
	Interest rate swap asset	$	520	$	520	Level 2	$	430	$	430	Level 2
	Liabilities:
	Accounts payable and accrued expenses(1)	$	16,098	$	16,098	Level 1	$	14,395	$	14,395	Level 1
	Interest rate swap liability	$	19,416	$	19,416	Level 2	$	6,417	$	6,417	Level 2
	Debt	$	2,326,109	$	2,373,488	Level 2	$	2,277,589	$	2,314,020	Level 2
	(1)	For the periods presented, the carrying value of these financial instruments approximates estimated fair value due to their short-term maturity.
	Piedmont's debt was carried at book value as of March 31, 2015 and December 31, 2014; however, Piedmont's estimate of its fair value is disclosed in the table above. Piedmont uses widely accepted valuation techniques including discounted cash flow analysis based on the contractual terms of the debt facilities, including the period to maturity of each instrument, and uses observable market-based inputs for similar debt facilities which have transacted recently in the market. Therefore, the estimated fair values determined are considered to be based on significant other observable inputs (Level 2). Scaling adjustments are made to these inputs to make them applicable to the remaining life of Piedmont's outstanding debt. Piedmont has not changed its valuation technique for estimating the fair value of its debt.
	Piedmont’s interest rate swap and forward starting interest rate swap agreements presented above, and 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 March 31, 2015 and December 31, 2014. The valuation of these derivative instruments was determined using widely accepted valuation techniques including discounted cash flow analysis based on the contractual terms of the derivatives, including the period to maturity of each instrument, and uses observable market-based inputs, including interest rate curves and implied volatilities. Therefore, the estimated fair values determined are considered to be based on significant other observable inputs (Level 2). In addition, Piedmont considered both its own and the respective counterparties’ risk of nonperformance in determining the estimated fair value of its derivative financial instruments by estimating the current and potential future exposure under the derivative financial instruments that both Piedmont and the counterparties were at risk for as of the valuation date. The credit risk of Piedmont and its counterparties was factored into the calculation of the estimated fair value of the interest rate swaps; however, as of March 31, 2015 and December 31, 2014, this credit valuation adjustment did not comprise a material portion of the estimated fair value. Therefore, Piedmont believes that any unobservable inputs used to determine the estimated fair values of its derivative financial instruments are not significant to the fair value measurements in their entirety, and does not consider any of its derivative financial instruments to be Level 3 assets or liabilities.

Commitments_and_Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies
	Commitments Under Existing Lease Agreements
	Certain lease agreements include provisions that, at the option of the tenant, may obligate Piedmont to provide funding for capital improvements. Under its existing lease agreements, Piedmont may be required to fund significant tenant improvements, leasing commissions, and building improvements. In addition, certain agreements contain provisions that require Piedmont to issue corporate or property guarantees to provide funding for capital improvements or other financial obligations. Further, Piedmont classifies such tenant and building improvements into two categories: (i) improvements which incrementally enhance the building's asset value by expanding its revenue generating capacity (“incremental capital expenditures”) and (ii) improvements which maintain the building's existing asset value and its revenue generating capacity (“non-incremental capital expenditures”). As of March 31, 2015, commitments for funding potential non-incremental capital expenditures over the next five years for tenant improvements totaled approximately $46.1 million related to Piedmont's existing lease portfolio over the respective lease terms, the majority of which Piedmont estimates may be required to be funded over the next three years based on when the underlying leases commence. For most of Piedmont’s leases, the timing of the actual funding of these tenant improvements is largely dependent upon tenant requests for reimbursement. In some cases, these obligations may expire with the leases without further recourse to Piedmont.
	Additionally, as of March 31, 2015, commitments for incremental capital expenditures for tenant improvements associated with new and existing leases, primarily at value-add properties, totaled approximately $23.8 million.
	Contingencies Related to Tenant Audits/Disputes
	Certain lease agreements include provisions that grant tenants the right to engage independent auditors to audit their annual operating expense reconciliations. Such audits may result in the re-interpretation of language in the lease agreements which could result in the refund of previously recognized tenant reimbursement revenues, resulting in financial loss to Piedmont. Piedmont recorded reductions in reimbursement revenues related to such tenant audits/disputes of approximately $0 and $0.3 million during the three months ended March 31, 2015 and 2014, respectively.
	Letters of Credit
	As of March 31, 2015, Piedmont was subject to a letter of credit of approximately $0.4 million, which reduces the total outstanding capacity under its $500 Million Unsecured Line of Credit. This letter of credit agreement is scheduled to expire in July 2015; however, it contains an automatic renewal feature, consisting of successive one-year renewal periods, subject to the satisfaction of the credit obligation and certain other limitations.

Assets_Held_for_Sale_and_Disco

Assets Held for Sale and Discontinued Operations	3 Months Ended
	Mar. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Assets Held for Sale and Discontinued Operations	Assets Held for Sale and Discontinued Operations
	Assets Held for Sale
	Assets held for sale as of December 31, 2014 consisted solely of the 3900 Dallas Parkway building. Details are presented below (in thousands):
			March 31, 2015				December 31, 2014
	Real estate assets held for sale, net:
	Land		$	—			$	1,517
	Building and improvements, less accumulated depreciation of $10,342 as of December 31, 2014		—				13,027
	Total real estate assets held for sale, net		$	—			$	14,544
	Other assets held for sale, net:
	Straight-line rent receivables		$	—			$	768
	Deferred lease costs, less accumulated amortization of $1,552 as of December 31, 2014		—				496
	Total other assets held for sale, net		$	—			$	1,264
	The 3900 Dallas Parkway building was subsequently sold during the three months ended March 31, 2015, and no other assets were held for sale as of March 31, 2015. The property was sold for approximately $26.2 million, resulting in a gain of approximately $10.1 million and net sales proceeds of approximately $25.8 million. As the sale of the 3900 Dallas Parkway building did not meet the criteria to be reported as a discontinued operation, the operational results for the building for periods prior to the sale are presented as continuing operations in the accompanying consolidated statements of income, and the gain on sale is presented separately on the face of the income statement.
	Discontinued Operations
	Asset disposals in previous periods that were previously classified as, and that continue to be reported as, discontinued operations for the three months ended March 31, 2015 and 2014 were as follows (in thousands):
	Buildings Sold		Location		Date of Sale		Gain/(Loss) on Sale			Net Sales Proceeds
	11107 and 11109 Sunset Hills Road		Reston, Virginia		March 19, 2014		$	(102	)	$	22,326
	1441 West Long Lake Road		Troy, Michigan		April 30, 2014		$	562		$	7,202
	4685 Investment Drive		Troy, Michigan		April 30, 2014		$	747		$	11,198
	Details comprising income from discontinued operations for the three months ended March 31, 2015 and 2014 are presented below (in thousands):
		Three Months Ended
		March 31, 2015				March 31, 2014
	Revenues:
	Rental income	$	—			$	1,174
	Tenant reimbursements	—				112
		—				1,286
	Expenses:
	Property operating costs	—				505
	Depreciation	—				83
	Amortization	—				223
	General and administrative	—				3
		—				814
	Other income/(expense)	—				(6		)
	Operating income, excluding gain on sale	—				466
	Gain on sale of real estate assets	—				(106		)
	Income from discontinued operations	$	—			$	360

Stock_Based_Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Based Compensation	Stock Based Compensation
	From time to time, Piedmont has granted equity awards to all of its employees. The deferred stock awards are determined by the Compensation Committee of the board of directors of Piedmont and typically vest on the award anniversary date ratably over a multi-year period. Piedmont also has a multi-year performance share program for certain of its employees whereby equity awards may be earned based on the relative performance of Piedmont's total stockholder return as compared with a predetermined peer group's total stockholder return over the same multi-year period. Shares are not awarded until after the end of the multi-year performance period and vest upon award.
	A rollforward of Piedmont's equity based award activity for the three months ended March 31, 2015 is as follows:
		Shares		Weighted-Average Grant Date Fair Value
	Unvested Deferred Stock Awards as of December 31, 2014	506,404		$	18.12
	Deferred Stock Awards Granted During Three Months Ended March 31, 2015	—		$	—
	Adjustment to Estimated Future Grants of Performance Share Awards During Three Months Ended March 31, 2015	(15,413	)	$	18.51
	Deferred Stock Awards Vested During Three Months Ended March 31, 2015	(20,976	)	$	16.48
	Deferred Stock Awards Forfeited During Three Months Ended March 31, 2015	—		$	—
	Unvested Deferred Stock Awards as of March 31, 2015	470,015		$	18.18
	The following table provides additional information regarding stock award activity during the three months ended March 31, 2015 and 2014, respectively (in thousands except for per share data):
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Weighted-Average Grant Date Fair Value of Shares Granted During the Period (per share)	$	—		$	16.45
	Total Grant Date Fair Value of Shares Vested During the Period	$	346		$	4
	Share-based Liability Awards Paid During the Period(1)	$	—		$	—
	(1)	Amount reflects the issuance of performance share awards during the period.
	A detail of Piedmont’s outstanding employee stock awards as of March 31, 2015 is as follows:
	Date of grant		Type of Award	Net Shares			Grant		Vesting Schedule	Unvested Shares as of March 31, 2015
				Granted (1)			Date Fair
							Value
	April 4, 2012		Deferred Stock Award	169,128			$	17.53	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on April 4, 2013, 2014, and 2015, respectively.	53,868
	April 2, 2013		Deferred Stock Award	132,826			$	19.47	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on April 2, 2014, 2015, and 2016, respectively.	76,156
	April 2, 2013		Fiscal Year 2013-2015 Performance Share Program	—			$	18.91	Shares awarded, if any, will vest immediately upon determination of award in 2016.	—	(2)
	January 3, 2014		Deferred Stock Award	95,476			$	16.45	Of the shares granted, 20% will vest on January 3, 2015, 2016, 2017, 2018, and 2019, respectively.	82,673
	May 9, 2014		Deferred Stock Award	179,897			$	18.47	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 9, 2015, 2016, and 2017, respectively.	144,287
	May 9, 2014		Fiscal Year 2014-2016 Performance Share Program	—			$	18.51	Shares awarded, if any, will vest immediately upon determination of award in 2017.	113,031	(3)
	Total									470,015
	(1)	Amounts reflect the total grant to employees, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through March 31, 2015.
	(2)	Estimated based on Piedmont's cumulative total stockholder return ("TSR") for the respective performance period through March 31, 2015. As of March 31, 2015, Piedmont's TSR for the fiscal year 2013-2015 performance share program was below threshold. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.
	(3)	Estimated based on Piedmont's cumulative TSR for the respective performance period through March 31, 2015. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.
	During the three months ended March 31, 2015 and 2014, Piedmont recognized approximately $0.9 million and $0.6 million of compensation expense related to stock awards, of which $0.8 million and $0.6 million related to the amortization of unvested shares, respectively. During the three months ended March 31, 2015, a net total of 15,418 shares were issued to employees, directors, and officers. As of March 31, 2015, approximately $2.3 million of unrecognized compensation cost related to unvested deferred stock awards remained, which Piedmont will record in its consolidated statements of income over a weighted-average vesting period of approximately one year.

Earnings_Per_Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share
	There are no adjustments to “Net income attributable to Piedmont” or “Income from continuing operations” for the diluted earnings per share computations.
	Net income per share-basic is calculated as net income available to common stockholders divided by the weighted average number of common shares outstanding during the period. Net income per share-diluted is calculated as net income available to common stockholders divided by the diluted weighted average number of common shares outstanding during the period, including unvested deferred stock awards. Diluted weighted average number of common shares reflects the potential dilution under the treasury stock method that would occur if the remaining unvested deferred stock awards vested and resulted in additional common shares outstanding. Certain unvested deferred stock awards are not included in the calculation because they would be anti-dilutive and have no effect for the periods presented.
	The following table reconciles the denominator for the basic and diluted earnings per share computations shown on the consolidated statements of income for the three months ended March 31, 2015 and 2014, respectively (in thousands):
		Three Months Ended
		March 31, 2015	March 31, 2014
	Weighted-average common shares – basic	154,339	154,849
	Plus incremental weighted-average shares from time-vested conversions:
	Deferred stock awards	241	176
	Weighted-average common shares – diluted	154,580	155,025

Guarantor_and_NonGuarantor_Fin

Guarantor and Non-Guarantor Financial Information	3 Months Ended
	Mar. 31, 2015
Guarantor and Non-Guarantor Financial Information [Abstract]
Guarantor and Non-Guarantor Financial Information	Guarantor and Non-Guarantor Financial Information
	The following condensed consolidating financial information for Piedmont Operating Partnership, L.P. (the "Issuer"), Piedmont Office Realty Trust, Inc. (the "Guarantor"), and the other directly and indirectly owned subsidiaries of the Guarantor (the "Non-Guarantor Subsidiaries") 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 principal elimination entries relate to investments in subsidiaries and intercompany balances and transactions, including transactions with the Non-Guarantor Subsidiaries.
	Condensed Consolidated Balance Sheets
	As of March 31, 2015
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Assets:
	Real estate assets, at cost:
	Land	$	81,406		$	—		$	625,934		$	—		$	707,340
	Buildings and improvements, less accumulated depreciation	438,933			—			2,795,862			(300		)	3,234,495
	Intangible lease assets, less accumulated amortization	1,676			—			67,578			—			69,254
	Construction in progress	3,032			—			80,821			—			83,853
	Total real estate assets	525,047			—			3,570,195			(300		)	4,094,942
	Investments in and amounts due from unconsolidated joint ventures	7,820			—			—			—			7,820
	Cash and cash equivalents	3,879			250			3,350			—			7,479
	Tenant and straight-line rent receivables, net	37,756			—			167,716			—			205,472
	Advances to affiliates	6,142,933			1,284,521			—			(7,427,454		)	—
	Investment in subsidiary	—			3,846,399			191			(3,846,590		)	—
	Notes receivable	161,350			—			23,890			(185,240		)	—
	Prepaid expenses, restricted cash, escrows, and other assets	6,129			116			22,567			(1,262		)	27,550
	Goodwill	180,097			—			—			—			180,097
	Interest rate swaps	520			—			—			—			520
	Deferred financing costs, net	7,023			—			368			—			7,391
	Deferred lease costs, net	31,445			—			257,146			—			288,591
	Total assets	$	7,103,999		$	5,131,286		$	4,045,423		$	(11,460,846	)	$	4,819,862
	Liabilities:
	Debt, net	$	1,901,208		$	—		$	610,141		$	(185,240	)	$	2,326,109
	Accounts payable, accrued expenses, and accrued capital expenditures	16,732			674			103,322			(1,262		)	119,466
	Advances from affiliates	392,696			4,909,707			2,185,841			(7,488,244		)	—
	Deferred income	5,150			—			20,820			—			25,970
	Intangible lease liabilities, net	—			—			42,978			—			42,978
	Interest rate swaps	19,416			—			—			—			19,416
	Total liabilities	2,335,202			4,910,381			2,963,102			(7,674,746		)	2,533,939
	Stockholders’ Equity:
	Common stock	—			1,543			—			—			1,543
	Additional paid-in capital	3,842,399			3,670,447			1,318			(3,846,590		)	3,667,574
	Retained/(cumulative distributions in excess of) earnings	931,835			(3,451,085		)	1,079,974			60,490			(1,378,786		)
	Other comprehensive loss	(5,437		)	—			—			—			(5,437		)
	Piedmont stockholders’ equity	4,768,797			220,905			1,081,292			(3,786,100		)	2,284,894
	Noncontrolling interest	—			—			1,029			—			1,029
	Total stockholders’ equity	4,768,797			220,905			1,082,321			(3,786,100		)	2,285,923
	Total liabilities and stockholders’ equity	$	7,103,999		$	5,131,286		$	4,045,423		$	(11,460,846	)	$	4,819,862
	Condensed Consolidated Balance Sheets
	As of December 31, 2014
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Assets:
	Real estate assets, at cost:
	Land	$	81,406		$	—		$	621,394		$	—		$	702,800
	Buildings and improvements, less accumulated depreciation	442,034			—			2,782,444			(300		)	3,224,178
	Intangible lease assets, less accumulated amortization	1,812			—			68,365			—			70,177
	Construction in progress	1,355			—			62,038			—			63,393
	Real estate assets held for sale, net	14,544			—			—			—			14,544
	Total real estate assets	541,151			—			3,534,241			(300		)	4,075,092
	Investments in and amounts due from unconsolidated joint ventures	7,798			—			—			—			7,798
	Cash and cash equivalents	8,143			1,790			2,373			—			12,306
	Tenant and straight-line rent receivables, net	37,238			—			160,005			—			197,243
	Advances to affiliates	6,084,243			1,282,443			—			(7,366,686		)	—
	Investment in subsidiary	—			3,878,811			192			(3,879,003		)	—
	Notes receivable	161,350			—			23,890			(185,240		)	—
	Prepaid expenses, restricted cash, escrows, and other assets	10,912			—			23,541			(954		)	33,499
	Goodwill	180,097			—			—			—			180,097
	Interest rate swaps	430			—			—			—			430
	Deferred financing costs, net	7,242			—			425			—			7,667
	Deferred lease costs, net	31,340			—			248,765			—			280,105
	Other assets held for sale, net	1,264			—			—			—			1,264
Total assets	$	7,071,208		$	5,163,044		$	3,993,432		$	(11,432,183	)	$	4,795,501
Liabilities:
Debt, net	$	1,852,434		$	—		$	610,395		$	(185,240	)	$	2,277,589
Accounts payable, accrued expenses, and accrued capital expenditures	19,403			465			115,074			(954		)	133,988
Advances from affiliates	376,122			4,909,362			2,138,140			(7,423,624		)	—
Deferred income	4,998			—			17,217			—			22,215
Intangible lease liabilities, net	—			—			43,277			—			43,277
Interest rate swaps	6,417			—			—			—			6,417
Total liabilities	2,259,374			4,909,827			2,924,103			(7,609,818		)	2,483,486
Stockholders’ Equity:
Common stock	—			1,543			—			—			1,543
Additional paid-in capital	3,874,757			3,670,236			192			(3,879,003		)	3,666,182
Retained/(cumulative distributions in excess of) earnings	928,776			(3,418,562		)	1,067,528			56,638			(1,365,620		)
Other comprehensive loss	8,301			—			—			—			8,301
Piedmont stockholders’ equity	4,811,834			253,217			1,067,720			(3,822,365		)	2,310,406
Noncontrolling interest	—			—			1,609			—			1,609
Total stockholders’ equity	4,811,834			253,217			1,069,329			(3,822,365		)	2,312,015
Total liabilities and stockholders’ equity	$	7,071,208		$	5,163,044		$	3,993,432		$	(11,432,183	)	$	4,795,501
Condensed Consolidated Statements of Income
For the three months ended March 31, 2015
(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
Revenues:
Rental income	$	18,937		$	—		$	99,577		$	(707	)	$	117,807
Tenant reimbursements	4,246			—			27,272			(128		)	31,390
Property management fee revenue	—			—			4,439			(3,877		)	562
	23,183			—			131,288			(4,712		)	149,759
Expenses:
Property operating costs	10,661			—			58,494			(4,919		)	64,236
Depreciation	5,803			—			30,429			—			36,232
Amortization	1,254			—			13,416			—			14,670
General and administrative	6,200			111			7,724			(7,628		)	6,407
	23,918			111			110,063			(12,547		)	121,545
Real estate operating income	(735		)	(111		)	21,225			7,835			28,214
Other income (expense):
Interest expense	(13,188		)	—			(8,949		)	3,121			(19,016		)
Other income/(expense)	2,766			—			174			(3,121		)	(181		)
Equity in income of unconsolidated joint ventures	159			—			—			—			159
	(10,263		)	—			(8,775		)	—			(19,038		)
Income from continuing operations	(10,998		)	(111		)	12,450			7,835			9,176
Discontinued operations:
Operating income	—			—			—			—			—
Income from discontinued operations	—			—			—			—			—
Gain on sale of real estate assets	10,073			—			—			—			10,073
Net income	(925		)	(111		)	12,450			7,835			19,249
Less: Net income attributable to noncontrolling interest	—			—			(4		)	—			(4		)
Net income attributable to Piedmont	$	(925	)	$	(111	)	$	12,446		$	7,835		$	19,245
Condensed Consolidated Statements of Income
For the three months ended March 31, 2014
(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
Revenues:
Rental income	$	17,400		$	—		$	95,157		$	(1,653	)	$	110,904
Tenant reimbursements	3,861			—			21,179			(111		)	24,929
Property management fee revenue	—			—			4,171			(3,684		)	487
	21,261			—			120,507			(5,448		)	136,320
Expenses:
Property operating costs	10,044			—			53,878			(5,651		)	58,271
Depreciation	5,840			—			27,804			—			33,644
Amortization	1,111			—			13,462			—			14,573
General and administrative	4,469			77			5,961			(5,952		)	4,555
	21,464			77			101,105			(11,603		)	111,043
Real estate operating income	(203		)	(77		)	19,402			6,155			25,277
Other income (expense):
Interest expense	(9,120		)	—			(12,939		)	3,133			(18,926		)
Other income/(expense)	2,762			35			246			(3,133		)	(90		)
Net recoveries/(loss) from casualty events and litigation settlements	1,351			—			1,691			—			3,042
Equity in income of unconsolidated joint ventures	(266		)	—			—			—			(266		)
	(5,273		)	35			(11,002		)	—			(16,240		)
Income from continuing operations	(5,476		)	(42		)	8,400			6,155			9,037
Discontinued operations:
Operating income	480			—			(14		)	—			466
Loss on sale of real estate assets	(106		)	—			—			—			(106		)
Income from discontinued operations	374			—			(14		)	—			360
Net income	(5,102		)	(42		)	8,386			6,155			9,397
Less: Net income attributable to noncontrolling interest	—			—			(4		)	—			(4		)
Net income attributable to Piedmont	$	(5,102	)	$	(42	)	$	8,382		$	6,155		$	9,393
Condensed Consolidated Statements of Cash Flows
For the three months ended March 31, 2015
(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
Net Cash Provided by Operating Activities	$	(6,974	)	$	426		$	42,343		$	7,835		$	43,630
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(5,091		)	—			(76,267		)	—			(81,358		)
Redemption of noncontrolling interest in unconsolidated variable interest entity	—			—			(4,000		)	—			(4,000		)
Net sales proceeds from wholly-owned properties	25,803			—			—			—			25,803
Deferred lease costs paid	(846		)	—			(3,568		)	—			(4,414		)
Net cash used in investing activities	19,866			—			(83,835		)	—			(63,969		)
Cash Flows from Financing Activities:
Deferred financing costs paid	(242		)	—			—			—			(242		)
Proceeds from debt	257,575			—			—			—			257,575
Repayments of debt	(209,000		)	—			(254		)	—			(209,254		)
Costs of issuance of common stock	—			(90		)	—			—			(90		)
(Distributions to)/repayments from affiliates	(65,489		)	30,601			42,723			(7,835		)	—
Dividends paid and discount on dividend reinvestments	—			(32,477		)	—			—			(32,477		)
Net cash provided by financing activities	(17,156		)	(1,966		)	42,469			(7,835		)	15,512
Net decrease in cash and cash equivalents	(4,264		)	(1,540		)	977			—			(4,827		)
Cash and cash equivalents, beginning of period	8,143			1,790			2,373			—			12,306
Cash and cash equivalents, end of period	$	3,879		$	250		$	3,350		$	—		$	7,479
Condensed Consolidated Statements of Cash Flows
For the three months ended March 31, 2014
(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
Net Cash Provided by Operating Activities	$	21,395		$	594		$	41,908		$	6,156		$	70,053
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	(6,875		)	—			(20,712		)	—			(27,587		)
Net sales proceeds from wholly-owned properties	22,322			—			—			—			22,322
Deferred lease costs paid	(720		)	—			(3,460		)	—			(4,180		)
Net cash used in investing activities	14,727			—			(24,172		)	—			(9,445		)
Cash Flows from Financing Activities:
Deferred financing costs paid	(454		)	—			—			—			(454		)
Proceeds from debt	764,564			—			—			—			764,564
Repayments of debt	(162,000		)	—			(575,000		)	—			(737,000		)
Repurchases of common stock as part of announced plan	—			(54,515		)	—			—			(54,515		)
(Distributions to)/repayments from affiliates	(635,361		)	84,826			556,691			(6,156		)	—
Dividends paid and discount on dividend reinvestments	—			(30,905		)	—			—			(30,905		)
Net cash used in financing activities	(33,251		)	(594		)	(18,309		)	(6,156		)	(58,310		)
Net increase in cash and cash equivalents	2,871			—			(573		)	—			2,298
Cash and cash equivalents, beginning of period	3,261			150			3,562			—			6,973
Cash and cash equivalents, end of period	$	6,132		$	150		$	2,989		$	—		$	9,271

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events
	Second Quarter Dividend Declaration
	On April 28, 2015, the board of directors of Piedmont declared dividends for the second quarter of 2015 in the amount of $0.21 per common share outstanding to stockholders of record as of the close of business on May 29, 2015. Such dividends are to be paid on June 19, 2015.
	Property Dispositions
	On April 15, 2015, Piedmont entered into a binding contract to sell Copper Ridge Center, an approximately 268,000 square foot, multi-tenant office building located in Lyndhurst, New Jersey, constructed in 1989, and approximately 87% leased to various tenants, including anchor tenant, Ralph Lauren. The contract is subject to customary closing conditions and is anticipated to close during the second quarter of 2015.
	On April 28, 2015, Piedmont sold 5601 Headquarters Drive in Plano, Texas, an approximately 166,000 square foot office building constructed in 2001 and 100% leased to Intuit Inc.
	On April 29, 2015, Piedmont sold River Corporate Center in Tempe, Arizona, an approximately 133,000 square foot office building constructed in 1998 and 100% leased to US Foods, Inc., for $24.6 million, or $185 per square foot.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation and Principles of Consolidation	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 U.S. generally accepted accounting principles (“GAAP”) for complete financial statements. In the opinion of management, the statements for the unaudited interim periods presented include all adjustments, which are of a normal and recurring nature, necessary for a fair presentation of the results for such periods. Results for these interim periods are not necessarily indicative of a full year’s results.
Principles of Consolidation	Piedmont’s consolidated financial statements include the accounts of Piedmont, Piedmont’s wholly-owned subsidiaries, any variable interest entity ("VIE") of which Piedmont or any of its wholly-owned subsidiaries is considered to have the power to direct the activities of the entity and the obligation to absorb losses/right to receive benefits, or any entity in which Piedmont or any of its wholly-owned subsidiaries owns a controlling interest. In determining whether Piedmont or Piedmont OP has a controlling interest, the following factors, among others, are considered: equity ownership, voting rights, protective rights of investors, and participatory rights of investors. For further information, refer to the financial statements and footnotes included in Piedmont’s Annual Report on Form 10-K for the year ended December 31, 2014.
	All inter-company balances and transactions have been eliminated upon consolidation.
	Further, Piedmont has formed special purpose entities to acquire and hold real estate. Each special purpose entity is a separate legal entity and consequently the assets of the special purpose entities are not available to all creditors of Piedmont. The assets owned by these special purpose entities are being reported on a consolidated basis with Piedmont’s assets for financial reporting purposes only.
Use of Estimates	Use of Estimates
	The preparation of the accompanying consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the accompanying consolidated financial statements and notes. Actual results could differ from those estimates.
Income Taxes	Income Taxes
	Piedmont has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), and has operated as such, beginning with its taxable year ended December 31, 1998. To qualify as a REIT, Piedmont must meet certain organizational and operational requirements, including a requirement to distribute at least 90% of its annual REIT taxable income. As a REIT, Piedmont is generally not subject to federal income taxes. Piedmont is subject to certain taxes related to the operations of properties in certain locations, as well as operations conducted by its taxable REIT subsidiary, POH, which have been provided for in the financial statements.
Recent Accounting Pronouncements	Recent Accounting Pronouncements
	The Financial Accounting Standards Board (the "FASB") has issued Accounting Standards Update No. 2014-09, Revenue from Contracts with Customers (Topic 606) ("ASU 2014-09"). The amendments in ASU 2014-09 change the criteria for the recognition of revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services using a five-step determination process. Steps 1 through 5 involve (i) identifying contracts with a customer, (ii) identifying the performance obligations in the contract, (iii) determining the transaction price, (iv) allocating the transaction price to the performance obligations, and (v) recognizing revenue as an entity satisfies a performance obligation. Additionally, lease contracts are specifically excluded from ASU 2014-09. The amendments in ASU 2014-09 are effective in the first quarter of 2017 for Piedmont, and early adoption is not permitted. Piedmont is currently evaluating the potential impact, if any, of adoption.
	The FASB has issued Accounting Standards Update No. 2015-02, Consolidation (Topic 810), Amendments to the Consolidation Analysis ("ASU 2015-02"). The amendments in ASU 2015-02 modifies the consolidation analysis of certain types of entities. Specifically, ASU 2015-02 changes the assessment criteria of whether limited partnerships are VIEs, eliminates the presumption that general partners should consolidate a limited partner, eliminates certain conditions from the evaluation of whether a fee paid to a decision maker constitutes a VIE, and changes the evaluation regarding the impact of related parties in the primary beneficiary determination of a VIE. The amendments in ASU 2015-02 are effective in the first quarter of 2016 for Piedmont, and Piedmont is currently evaluating the potential impact, if any, of adoption.
	The FASB has issued Accounting Standards Update No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30), Simplifying the Presentation of Debt Issuance Costs ("ASU 2015-03"). The amendments in ASU 2015-03 require debt issuance costs to be presented in the balance sheet as a reduction to the underlying debt instrument, as opposed to a separate asset. The amendments do not change the method by which such costs are amortized against earnings, nor do they change their classification in the consolidated statements of income, as a component of interest expense. The amendments in ASU 2015-03 are effective in the first quarter of 2016 for Piedmont, and Piedmont is currently evaluating the potential impact of adoption.

Acquisitions_Tables

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	During the three months ended March 31, 2015, Piedmont acquired 100% ownership of the following property using proceeds from the $500 Million Unsecured Line of Credit, proceeds from the sale of the 3900 Dallas Parkway building in Plano, Texas (see Note 9), and cash on hand, as noted below:
	Property	Metropolitan Statistical Area	Date of Acquisition	Rentable Square Feet	Percentage Leased as of Acquisition		Purchase Price
							(in millions)
	Park Place on Turtle Creek	Dallas, TX	January 16, 2015	177,844	88	%	$	46.6

Debt_Tables

Debt (Tables)	3 Months Ended
	Mar. 31, 2015
Debt Disclosure [Abstract]
Schedule of Debt	The following table summarizes the terms of Piedmont’s indebtedness outstanding as of March 31, 2015 and December 31, 2014 (in thousands):
	Facility		Collateral	Stated Rate(1)			Maturity		Amount Outstanding as of
									March 31,		December 31,
									2015		2014
	Secured (Fixed)
	$105 Million Fixed-Rate Loan		US Bancorp Center	5.29	%	(2)	5/11/15		$	105,000	$	105,000
	$125 Million Fixed-Rate Loan		Four Property Collateralized	5.5	%		4/1/16		125,000		125,000
			Pool (3)
	$42.5 Million Fixed-Rate Loan		Las Colinas Corporate	5.7	%		10/11/16		42,525		42,525
			Center I & II
	$140 Million WDC Fixed-Rate Loans		1201 & 1225 Eye Street	5.76	%		11/1/17		140,000		140,000
	$35 Million Fixed-Rate Loan		5 Wall Street	5.55	%	(4)	9/1/21		36,266		36,520
	Subtotal/Weighted Average (5)			5.56	%				448,791		449,045
	Unsecured (Variable and Fixed)
	$300 Million Unsecured 2011 Term Loan			LIBOR +  1.15%		(6)	1/15/20		298,996		298,944
	$500 Million Unsecured Line of Credit			LIBOR + 1.175%		(7)	8/19/16	(8)	363,000		434,000
	$350 Million Unsecured Senior Notes			3.4	%	(9)	6/1/23		348,831		348,800
	$300 Million Unsecured 2013 Term Loan			LIBOR + 1.20%		(10)	1/31/19		300,000		300,000
	$400 Million Unsecured Senior Notes			4.45	%	(11)	3/15/24		396,914		396,832
	$50 Million Unsecured Term Loan			LIBOR + 1.15%			4/1/15		—		49,968
	$170 Million Unsecured 2015 Term Loan			LIBOR + 1.125%		(12)	5/15/18		169,577		—
	Subtotal/Weighted Average (5)			2.78	%				1,877,318		1,828,544
	Total/ Weighted Average (5)			3.31	%				$	2,326,109	$	2,277,589
	(1)	Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of March 31, 2015 and December 31, 2014 is interest-only.
	(2)	On April 10, 2015, Piedmont repaid in full the balance on the $105 Million Fixed-Rate Loan.
	(3)	Property collateralized pool includes 1430 Enclave Parkway in Houston, Texas, Windy Point I and II in Schaumburg, Illinois, and 1055 East Colorado Boulevard in Pasadena, California.
	(4)	The $35 Million Fixed-Rate Loan has a contractual fixed rate of 5.55% ; however, the amortization of the premium recorded in order to adjust the note to its estimated fair value, results in an effective interest rate of 3.75%.
	(5)	Weighted average is based on contractual balance of outstanding debt and interest rates in the table as of March 31, 2015.
	(6)	The $300 Million Unsecured 2011 Term Loan 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, the rate on this facility to 2.39% through the original maturity date of November 22, 2016 and 3.35% from November 22, 2016 to January 15, 2020.
	(7)	Piedmont may select from multiple interest rate options with each draw, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.175% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of 30-day LIBOR draws at a rate of 0.18% (subject to the additional spread mentioned above).
	(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 August 21, 2017) provided Piedmont is not then in default and upon payment of extension fees.
	(9)	The $350 Million Senior Notes have a fixed coupon rate of 3.40%, however, as a result of the issuance of the notes at a discount, Piedmont recognizes an effective interest rate on this debt issuance of 3.45%. After consideration of the impact of settled interest rate swap agreements, in addition to the issuance discount, the effective interest rate on this debt is 3.43%.
	(10)	The $300 Million Unsecured 2013 Term Loan has a stated variable rate; however, Piedmont entered into interest rate swap agreements which effectively fix, absent any changes to Piedmont's credit rating, the rate on this facility to 2.78% .
	(11)	The $400 Million Senior Notes have a fixed coupon rate of 4.45%, however, as a result of the issuance of the notes at a discount, Piedmont recognizes an effective interest rate on this debt issuance of 4.48%. After consideration of the impact of settled interest rate swap agreements, in addition to the issuance discount, the effective interest rate on this debt is 4.10%.
	(12)	Piedmont may select from multiple interest rate options, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.125% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of a 30-day LIBOR draw at a rate of 0.18% (subject to the additional spread mentioned above).

Derivative_Instruments_Tables

Derivative Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions	The detail of Piedmont’s interest rate derivatives outstanding as of March 31, 2015 is as follows:
	Interest Rate Derivatives:		Number of Swap Agreements		Associated Debt Instrument		Total Notional Amount		Effective Date	Maturity Date
							(in millions)
	Interest rate swaps		4		$300 Million Unsecured 2011 Term Loan		$	300	11/22/11	11/22/16
	Interest rate swaps		4		$300 Million Unsecured 2013 Term Loan		200		1/30/14	1/31/19
	Interest rate swaps		2		$300 Million Unsecured 2013 Term Loan		100		8/29/14	1/31/19
	Forward starting interest rate swaps		3		$300 Million Unsecured 2011 Term Loan		300		11/22/16	1/15/20
	Forward starting interest rate swaps		4		Potential Future Issuance		250		2/27/15	2/27/22
	Forward starting interest rate swaps		4		Potential Future Issuance		250		2/25/16	2/25/26
	Total						$	1,400
Schedule of Interest Rate Derivatives	The detail of Piedmont’s interest rate derivatives on a gross and net basis as of March 31, 2015 and December 31, 2014, respectively, is as follows (in thousands):
	Interest rate swaps classified as:	March 31,				December 31,
		2015				2014
	Gross derivative assets	$	520			$	430
	Gross derivative liabilities	(19,416		)		(6,417		)
	Net derivative liability	$	(18,896	)		$	(5,987	)
Schedule of Derivative Instruments, Effect on Other Comprehensive Income (Loss)	The effective portion of Piedmont's interest rate derivatives, including the gain on settlement of forward swaps described above, that was recorded in the accompanying consolidated statements of income for the three months ended March 31, 2015 and 2014, respectively, was as follows:
		Three Months Ended
	Derivative in	March 31,				March 31,
	Cash Flow Hedging	2015				2014
	Relationships (Interest Rate Swaps) (in thousands)
	Amount of gain/(loss) recognized in OCI on derivative	$	(15,205	)		$	(9,886	)
	Amount of previously recorded loss reclassified from accumulated OCI into interest expense	$	1,467			$	1,170

Variable_Interest_Entities_and1

Variable Interest Entities and Equity Participation Rights (Tables)	3 Months Ended
	Mar. 31, 2015
Variable Interest Entities [Abstract]
Schedule of Variable Interest Entities	A summary of Piedmont’s interests in and consolidation treatment of its outstanding VIEs as of March 31, 2015 and their related carrying values as of December 31, 2014 is as follows (net carrying amount in millions):
	Entity	Piedmont’s	Related	Consolidated/	Net Carrying			Net Carrying			Primary Beneficiary
		%	Building	Unconsolidated	Amount as of			Amount as of			Considerations
		Ownership			31-Mar-15			December 31,
		of Entity						2014
	1201 Eye Street NW Associates, LLC	49.50%	1201 Eye Street	Consolidated	$	(2.5	)	$	(2.8	)	In accordance with the partnership’s governing documents, Piedmont is entitled to 100% of the cash flow of the entity until certain financial returns are achieved and has sole discretion in directing the management and leasing activities of the building.
	1225 Eye Street NW Associates, LLC	49.50%	1225 Eye Street	Consolidated	$	0.6		$	(1.1	)	In accordance with the partnership’s governing documents, Piedmont is entitled to 100% of the cash flow of the entity until certain financial returns are achieved and has sole discretion in directing the management and leasing activities of the building.
	Piedmont 500 W. Monroe Fee, LLC	100%	500 W. Monroe	Consolidated	$	245.7		$	245.3		The Omnibus Agreement with the previous owner includes equity participation rights for the previous owner, if certain financial returns are achieved; however, Piedmont has sole decision making authority and is entitled to the economic benefits of the property until such returns are met.
	Piedmont TownPark Land, LLC	100%	Land Parcel Adjacent to 400 TownPark building	Consolidated	$	7.9		$	7.9		The equity participation and service fee agreement includes equity participation rights for the third party manager if certain defined events occur and certain returns on investment are achieved; however, Piedmont has sole decision making authority and is entitled to the economic benefits of the property until such events occur and returns are achieved.

Fair_Value_Measurement_of_Fina1

Fair Value Measurement of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value, by Balance Sheet Grouping	The following table sets forth the carrying and estimated fair value for each of Piedmont’s financial instruments, as well as its level within the GAAP fair value hierarchy, as of March 31, 2015 and December 31, 2014, respectively (in thousands):
		March 31, 2015					December 31, 2014
	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)	$	7,479	$	7,479	Level 1	$	12,306	$	12,306	Level 1
	Tenant receivables, net(1)	$	30,132	$	30,132	Level 1	$	27,711	$	27,711	Level 1
	Restricted cash and escrows(1)	$	671	$	671	Level 1	$	5,679	$	5,679	Level 1
	Interest rate swap asset	$	520	$	520	Level 2	$	430	$	430	Level 2
	Liabilities:
	Accounts payable and accrued expenses(1)	$	16,098	$	16,098	Level 1	$	14,395	$	14,395	Level 1
	Interest rate swap liability	$	19,416	$	19,416	Level 2	$	6,417	$	6,417	Level 2
	Debt	$	2,326,109	$	2,373,488	Level 2	$	2,277,589	$	2,314,020	Level 2
	(1)	For the periods presented, the carrying value of these financial instruments approximates estimated fair value due to their short-term maturity.

Assets_Held_for_Sale_and_Disco1

Assets Held for Sale and Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2015
Discontinued Operations and Disposal Groups [Abstract]
Disclosure of Long Lived Assets Held-for-sale	Assets held for sale as of December 31, 2014 consisted solely of the 3900 Dallas Parkway building. Details are presented below (in thousands):
			March 31, 2015				December 31, 2014
	Real estate assets held for sale, net:
	Land		$	—			$	1,517
	Building and improvements, less accumulated depreciation of $10,342 as of December 31, 2014		—				13,027
	Total real estate assets held for sale, net		$	—			$	14,544
	Other assets held for sale, net:
	Straight-line rent receivables		$	—			$	768
	Deferred lease costs, less accumulated amortization of $1,552 as of December 31, 2014		—				496
	Total other assets held for sale, net		$	—			$	1,264
Schedule of Disposal Groups, Including Discontinued Operations, Results Of Operations	Asset disposals in previous periods that were previously classified as, and that continue to be reported as, discontinued operations for the three months ended March 31, 2015 and 2014 were as follows (in thousands):
	Buildings Sold		Location		Date of Sale		Gain/(Loss) on Sale			Net Sales Proceeds
	11107 and 11109 Sunset Hills Road		Reston, Virginia		March 19, 2014		$	(102	)	$	22,326
	1441 West Long Lake Road		Troy, Michigan		April 30, 2014		$	562		$	7,202
	4685 Investment Drive		Troy, Michigan		April 30, 2014		$	747		$	11,198
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures	Details comprising income from discontinued operations for the three months ended March 31, 2015 and 2014 are presented below (in thousands):
		Three Months Ended
		March 31, 2015				March 31, 2014
	Revenues:
	Rental income	$	—			$	1,174
	Tenant reimbursements	—				112
		—				1,286
	Expenses:
	Property operating costs	—				505
	Depreciation	—				83
	Amortization	—				223
	General and administrative	—				3
		—				814
	Other income/(expense)	—				(6		)
	Operating income, excluding gain on sale	—				466
	Gain on sale of real estate assets	—				(106		)
	Income from discontinued operations	$	—			$	360

Stock_Based_Compensation_Table

Stock Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Nonvested Share Activity	A rollforward of Piedmont's equity based award activity for the three months ended March 31, 2015 is as follows:
		Shares		Weighted-Average Grant Date Fair Value
	Unvested Deferred Stock Awards as of December 31, 2014	506,404		$	18.12
	Deferred Stock Awards Granted During Three Months Ended March 31, 2015	—		$	—
	Adjustment to Estimated Future Grants of Performance Share Awards During Three Months Ended March 31, 2015	(15,413	)	$	18.51
	Deferred Stock Awards Vested During Three Months Ended March 31, 2015	(20,976	)	$	16.48
	Deferred Stock Awards Forfeited During Three Months Ended March 31, 2015	—		$	—
	Unvested Deferred Stock Awards as of March 31, 2015	470,015		$	18.18
	The following table provides additional information regarding stock award activity during the three months ended March 31, 2015 and 2014, respectively (in thousands except for per share data):
		Three Months Ended
		March 31,			March 31,
		2015			2014
	Weighted-Average Grant Date Fair Value of Shares Granted During the Period (per share)	$	—		$	16.45
	Total Grant Date Fair Value of Shares Vested During the Period	$	346		$	4
	Share-based Liability Awards Paid During the Period(1)	$	—		$	—
	(1)	Amount reflects the issuance of performance share awards during the period.
Schedule of Outstanding Employee Deferred Stock Awards	A detail of Piedmont’s outstanding employee stock awards as of March 31, 2015 is as follows:
	Date of grant		Type of Award	Net Shares			Grant		Vesting Schedule	Unvested Shares as of March 31, 2015
				Granted (1)			Date Fair
							Value
	April 4, 2012		Deferred Stock Award	169,128			$	17.53	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on April 4, 2013, 2014, and 2015, respectively.	53,868
	April 2, 2013		Deferred Stock Award	132,826			$	19.47	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on April 2, 2014, 2015, and 2016, respectively.	76,156
	April 2, 2013		Fiscal Year 2013-2015 Performance Share Program	—			$	18.91	Shares awarded, if any, will vest immediately upon determination of award in 2016.	—	(2)
	January 3, 2014		Deferred Stock Award	95,476			$	16.45	Of the shares granted, 20% will vest on January 3, 2015, 2016, 2017, 2018, and 2019, respectively.	82,673
	May 9, 2014		Deferred Stock Award	179,897			$	18.47	Of the shares granted, 25% vested on the date of grant, and 25% vested or will vest on May 9, 2015, 2016, and 2017, respectively.	144,287
	May 9, 2014		Fiscal Year 2014-2016 Performance Share Program	—			$	18.51	Shares awarded, if any, will vest immediately upon determination of award in 2017.	113,031	(3)
	Total									470,015
	(1)	Amounts reflect the total grant to employees, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through March 31, 2015.
	(2)	Estimated based on Piedmont's cumulative total stockholder return ("TSR") for the respective performance period through March 31, 2015. As of March 31, 2015, Piedmont's TSR for the fiscal year 2013-2015 performance share program was below threshold. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.
	(3)	Estimated based on Piedmont's cumulative TSR for the respective performance period through March 31, 2015. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares	The following table reconciles the denominator for the basic and diluted earnings per share computations shown on the consolidated statements of income for the three months ended March 31, 2015 and 2014, respectively (in thousands):
		Three Months Ended
		March 31, 2015	March 31, 2014
	Weighted-average common shares – basic	154,339	154,849
	Plus incremental weighted-average shares from time-vested conversions:
	Deferred stock awards	241	176
	Weighted-average common shares – diluted	154,580	155,025

Guarantor_and_NonGuarantor_Fin1

Guarantor and Non-Guarantor Financial Information (Tables)	3 Months Ended
	Mar. 31, 2015
Guarantor and Non-Guarantor Financial Information [Abstract]
Condensed Consolidated Balance Sheets
	Condensed Consolidated Balance Sheets
	As of March 31, 2015
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Assets:
	Real estate assets, at cost:
	Land	$	81,406		$	—		$	625,934		$	—		$	707,340
	Buildings and improvements, less accumulated depreciation	438,933			—			2,795,862			(300		)	3,234,495
	Intangible lease assets, less accumulated amortization	1,676			—			67,578			—			69,254
	Construction in progress	3,032			—			80,821			—			83,853
	Total real estate assets	525,047			—			3,570,195			(300		)	4,094,942
	Investments in and amounts due from unconsolidated joint ventures	7,820			—			—			—			7,820
	Cash and cash equivalents	3,879			250			3,350			—			7,479
	Tenant and straight-line rent receivables, net	37,756			—			167,716			—			205,472
	Advances to affiliates	6,142,933			1,284,521			—			(7,427,454		)	—
	Investment in subsidiary	—			3,846,399			191			(3,846,590		)	—
	Notes receivable	161,350			—			23,890			(185,240		)	—
	Prepaid expenses, restricted cash, escrows, and other assets	6,129			116			22,567			(1,262		)	27,550
	Goodwill	180,097			—			—			—			180,097
	Interest rate swaps	520			—			—			—			520
	Deferred financing costs, net	7,023			—			368			—			7,391
	Deferred lease costs, net	31,445			—			257,146			—			288,591
	Total assets	$	7,103,999		$	5,131,286		$	4,045,423		$	(11,460,846	)	$	4,819,862
	Liabilities:
	Debt, net	$	1,901,208		$	—		$	610,141		$	(185,240	)	$	2,326,109
	Accounts payable, accrued expenses, and accrued capital expenditures	16,732			674			103,322			(1,262		)	119,466
	Advances from affiliates	392,696			4,909,707			2,185,841			(7,488,244		)	—
	Deferred income	5,150			—			20,820			—			25,970
	Intangible lease liabilities, net	—			—			42,978			—			42,978
	Interest rate swaps	19,416			—			—			—			19,416
	Total liabilities	2,335,202			4,910,381			2,963,102			(7,674,746		)	2,533,939
	Stockholders’ Equity:
	Common stock	—			1,543			—			—			1,543
	Additional paid-in capital	3,842,399			3,670,447			1,318			(3,846,590		)	3,667,574
	Retained/(cumulative distributions in excess of) earnings	931,835			(3,451,085		)	1,079,974			60,490			(1,378,786		)
	Other comprehensive loss	(5,437		)	—			—			—			(5,437		)
	Piedmont stockholders’ equity	4,768,797			220,905			1,081,292			(3,786,100		)	2,284,894
	Noncontrolling interest	—			—			1,029			—			1,029
	Total stockholders’ equity	4,768,797			220,905			1,082,321			(3,786,100		)	2,285,923
	Total liabilities and stockholders’ equity	$	7,103,999		$	5,131,286		$	4,045,423		$	(11,460,846	)	$	4,819,862
	Condensed Consolidated Balance Sheets
	As of December 31, 2014
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Assets:
	Real estate assets, at cost:
	Land	$	81,406		$	—		$	621,394		$	—		$	702,800
	Buildings and improvements, less accumulated depreciation	442,034			—			2,782,444			(300		)	3,224,178
	Intangible lease assets, less accumulated amortization	1,812			—			68,365			—			70,177
	Construction in progress	1,355			—			62,038			—			63,393
	Real estate assets held for sale, net	14,544			—			—			—			14,544
	Total real estate assets	541,151			—			3,534,241			(300		)	4,075,092
	Investments in and amounts due from unconsolidated joint ventures	7,798			—			—			—			7,798
	Cash and cash equivalents	8,143			1,790			2,373			—			12,306
	Tenant and straight-line rent receivables, net	37,238			—			160,005			—			197,243
	Advances to affiliates	6,084,243			1,282,443			—			(7,366,686		)	—
	Investment in subsidiary	—			3,878,811			192			(3,879,003		)	—
	Notes receivable	161,350			—			23,890			(185,240		)	—
	Prepaid expenses, restricted cash, escrows, and other assets	10,912			—			23,541			(954		)	33,499
	Goodwill	180,097			—			—			—			180,097
	Interest rate swaps	430			—			—			—			430
	Deferred financing costs, net	7,242			—			425			—			7,667
	Deferred lease costs, net	31,340			—			248,765			—			280,105
	Other assets held for sale, net	1,264			—			—			—			1,264
	Total assets	$	7,071,208		$	5,163,044		$	3,993,432		$	(11,432,183	)	$	4,795,501
Liabilities:
Debt, net	$	1,852,434		$	—		$	610,395		$	(185,240	)	$	2,277,589
Accounts payable, accrued expenses, and accrued capital expenditures	19,403			465			115,074			(954		)	133,988
Advances from affiliates	376,122			4,909,362			2,138,140			(7,423,624		)	—
Deferred income	4,998			—			17,217			—			22,215
Intangible lease liabilities, net	—			—			43,277			—			43,277
Interest rate swaps	6,417			—			—			—			6,417
Total liabilities	2,259,374			4,909,827			2,924,103			(7,609,818		)	2,483,486
Stockholders’ Equity:
Common stock	—			1,543			—			—			1,543
Additional paid-in capital	3,874,757			3,670,236			192			(3,879,003		)	3,666,182
Retained/(cumulative distributions in excess of) earnings	928,776			(3,418,562		)	1,067,528			56,638			(1,365,620		)
Other comprehensive loss	8,301			—			—			—			8,301
Piedmont stockholders’ equity	4,811,834			253,217			1,067,720			(3,822,365		)	2,310,406
Noncontrolling interest	—			—			1,609			—			1,609
Total stockholders’ equity	4,811,834			253,217			1,069,329			(3,822,365		)	2,312,015
Total liabilities and stockholders’ equity	$	7,071,208		$	5,163,044		$	3,993,432		$	(11,432,183	)	$	4,795,501
Condensed Consolidated Statements of Income
	Condensed Consolidated Statements of Income
	For the three months ended March 31, 2015
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Revenues:
	Rental income	$	18,937		$	—		$	99,577		$	(707	)	$	117,807
	Tenant reimbursements	4,246			—			27,272			(128		)	31,390
	Property management fee revenue	—			—			4,439			(3,877		)	562
		23,183			—			131,288			(4,712		)	149,759
	Expenses:
	Property operating costs	10,661			—			58,494			(4,919		)	64,236
	Depreciation	5,803			—			30,429			—			36,232
	Amortization	1,254			—			13,416			—			14,670
	General and administrative	6,200			111			7,724			(7,628		)	6,407
		23,918			111			110,063			(12,547		)	121,545
	Real estate operating income	(735		)	(111		)	21,225			7,835			28,214
	Other income (expense):
	Interest expense	(13,188		)	—			(8,949		)	3,121			(19,016		)
	Other income/(expense)	2,766			—			174			(3,121		)	(181		)
	Equity in income of unconsolidated joint ventures	159			—			—			—			159
		(10,263		)	—			(8,775		)	—			(19,038		)
	Income from continuing operations	(10,998		)	(111		)	12,450			7,835			9,176
	Discontinued operations:
	Operating income	—			—			—			—			—
	Income from discontinued operations	—			—			—			—			—
	Gain on sale of real estate assets	10,073			—			—			—			10,073
	Net income	(925		)	(111		)	12,450			7,835			19,249
	Less: Net income attributable to noncontrolling interest	—			—			(4		)	—			(4		)
	Net income attributable to Piedmont	$	(925	)	$	(111	)	$	12,446		$	7,835		$	19,245
	Condensed Consolidated Statements of Income
	For the three months ended March 31, 2014
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Revenues:
	Rental income	$	17,400		$	—		$	95,157		$	(1,653	)	$	110,904
	Tenant reimbursements	3,861			—			21,179			(111		)	24,929
	Property management fee revenue	—			—			4,171			(3,684		)	487
		21,261			—			120,507			(5,448		)	136,320
	Expenses:
	Property operating costs	10,044			—			53,878			(5,651		)	58,271
	Depreciation	5,840			—			27,804			—			33,644
	Amortization	1,111			—			13,462			—			14,573
	General and administrative	4,469			77			5,961			(5,952		)	4,555
		21,464			77			101,105			(11,603		)	111,043
	Real estate operating income	(203		)	(77		)	19,402			6,155			25,277
	Other income (expense):
	Interest expense	(9,120		)	—			(12,939		)	3,133			(18,926		)
	Other income/(expense)	2,762			35			246			(3,133		)	(90		)
	Net recoveries/(loss) from casualty events and litigation settlements	1,351			—			1,691			—			3,042
	Equity in income of unconsolidated joint ventures	(266		)	—			—			—			(266		)
		(5,273		)	35			(11,002		)	—			(16,240		)
	Income from continuing operations	(5,476		)	(42		)	8,400			6,155			9,037
	Discontinued operations:
	Operating income	480			—			(14		)	—			466
	Loss on sale of real estate assets	(106		)	—			—			—			(106		)
	Income from discontinued operations	374			—			(14		)	—			360
	Net income	(5,102		)	(42		)	8,386			6,155			9,397
	Less: Net income attributable to noncontrolling interest	—			—			(4		)	—			(4		)
	Net income attributable to Piedmont	$	(5,102	)	$	(42	)	$	8,382		$	6,155		$	9,393
Condensed Consolidated Statements of Cash Flows
	Condensed Consolidated Statements of Cash Flows
	For the three months ended March 31, 2015
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Net Cash Provided by Operating Activities	$	(6,974	)	$	426		$	42,343		$	7,835		$	43,630
	Cash Flows from Investing Activities:
	Investment in real estate assets and real estate related intangibles, net of accruals	(5,091		)	—			(76,267		)	—			(81,358		)
	Redemption of noncontrolling interest in unconsolidated variable interest entity	—			—			(4,000		)	—			(4,000		)
	Net sales proceeds from wholly-owned properties	25,803			—			—			—			25,803
	Deferred lease costs paid	(846		)	—			(3,568		)	—			(4,414		)
	Net cash used in investing activities	19,866			—			(83,835		)	—			(63,969		)
	Cash Flows from Financing Activities:
	Deferred financing costs paid	(242		)	—			—			—			(242		)
	Proceeds from debt	257,575			—			—			—			257,575
	Repayments of debt	(209,000		)	—			(254		)	—			(209,254		)
	Costs of issuance of common stock	—			(90		)	—			—			(90		)
	(Distributions to)/repayments from affiliates	(65,489		)	30,601			42,723			(7,835		)	—
	Dividends paid and discount on dividend reinvestments	—			(32,477		)	—			—			(32,477		)
	Net cash provided by financing activities	(17,156		)	(1,966		)	42,469			(7,835		)	15,512
	Net decrease in cash and cash equivalents	(4,264		)	(1,540		)	977			—			(4,827		)
	Cash and cash equivalents, beginning of period	8,143			1,790			2,373			—			12,306
	Cash and cash equivalents, end of period	$	3,879		$	250		$	3,350		$	—		$	7,479
	Condensed Consolidated Statements of Cash Flows
	For the three months ended March 31, 2014
	(in thousands)	Issuer			Guarantor			Non-Guarantor Subsidiaries			Eliminations			Consolidated
	Net Cash Provided by Operating Activities	$	21,395		$	594		$	41,908		$	6,156		$	70,053
	Cash Flows from Investing Activities:
	Investment in real estate assets and real estate related intangibles, net of accruals	(6,875		)	—			(20,712		)	—			(27,587		)
	Net sales proceeds from wholly-owned properties	22,322			—			—			—			22,322
	Deferred lease costs paid	(720		)	—			(3,460		)	—			(4,180		)
	Net cash used in investing activities	14,727			—			(24,172		)	—			(9,445		)
	Cash Flows from Financing Activities:
	Deferred financing costs paid	(454		)	—			—			—			(454		)
	Proceeds from debt	764,564			—			—			—			764,564
	Repayments of debt	(162,000		)	—			(575,000		)	—			(737,000		)
	Repurchases of common stock as part of announced plan	—			(54,515		)	—			—			(54,515		)
	(Distributions to)/repayments from affiliates	(635,361		)	84,826			556,691			(6,156		)	—
	Dividends paid and discount on dividend reinvestments	—			(30,905		)	—			—			(30,905		)
	Net cash used in financing activities	(33,251		)	(594		)	(18,309		)	(6,156		)	(58,310		)
	Net increase in cash and cash equivalents	2,871			—			(573		)	—			2,298
	Cash and cash equivalents, beginning of period	3,261			150			3,562			—			6,973
	Cash and cash equivalents, end of period	$	6,132		$	150		$	2,989		$	—		$	9,271

Organization_Details

Organization (Details)	3 Months Ended
	Mar. 31, 2015
	Segment
	subsidiary
Real Estate Properties [Line Items]
Number of wholly-owned subsidiaries	2
Percentage ownership by sole general partner	99.90%
Percentage ownership by sole limited partner	0.10%
Percentage of annualized lease revenue	90.00%
Number of operating segments	1
Unconsolidated Joint Venture [Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Office properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	74
Number of redevelopment assets	1
Square footage of real estate property	21,500,000
Percentage Leased as of Acquisition	88.80%

Summary_of_Significant_Account2

Summary of Significant Accounting Policies (Details) (Minimum [Member])	3 Months Ended
	Mar. 31, 2015
Minimum [Member]
Income Tax For Real Estate Investment Trusts [Line Items]
Real estate investment trust status required taxable income distribution rate	90.00%

Acquisitions_Details

Acquisitions (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
	sqft
Business Acquisition [Line Items]
Ownership of properties acquired	100.00%
$500 Million Unsecured Line of Credit [Member] | Unsecured Debt [Member]
Business Acquisition [Line Items]
Face amount of debt instrument	$500,000,000
Park Place on Turtle Creek [Member]
Business Acquisition [Line Items]
Area of property	177,844
Percentage Leased as of Acquisition	88.00%
Purchase Price (in millions)	$46,600,000

Debt_Narrative_Details

Debt (Narrative) (Details) (USD $)	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Debt Instrument [Line Items]
Interest payments on debt facilities	$20,400,000		$16,500,000
Capitalized interest	800,000		400,000
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument [Line Items]
Interest rate period	1 year
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest rate period	1 month
London Interbank Offered Rate (LIBOR), One Month [Member]
Debt Instrument [Line Items]
Interest rate period	1 month
London Interbank Offered Rate (LIBOR), Two Months [Member]
Debt Instrument [Line Items]
Interest rate period	2 months
London Interbank Offered Rate (LIBOR), Three Months [Member]
Debt Instrument [Line Items]
Interest rate period	3 months
London Interbank Offered Rate (LIBOR), Six Months [Member]
Debt Instrument [Line Items]
Interest rate period	6 months
$170 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.00%
Rate	1.13%
$170 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.75%
$170 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	0.90%
$50 Million Unsecured Term Loan [Member] | Bridge Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	50,000,000
Unsecured Debt [Member] | $170 Million Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	170,000,000
Term of Unsecured Term Loan	3 years
Unencumbered interest coverage ratio	1.75
Unencumbered leverage ratio	1.6
Fixed charge coverage ratio	1.5
Leverage ratio	0.6
Secured debt ratio	0.4
Unsecured Debt [Member] | $170 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.13%	[1],[2]
Unsecured Debt [Member] | $170 Million Unsecured Term Loan [Member] | Federal Funds Rate [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	0.50%
Unsecured Debt [Member] | $50 Million Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	50,000,000
Unsecured Debt [Member] | $50 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.15%	[1]
Unsecured Debt [Member] | $500 Million Unsecured Line of Credit [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	500,000,000
Basis spread on variable rate	1.18%
Net borrowings	88,000,000
Repayments	($159,000,000)
Unsecured Debt [Member] | $500 Million Unsecured Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.18%	[1],[3]
[1]	Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of March 31, 2015 and December 31, 2014 is interest-only.
[2]	Piedmont may select from multiple interest rate options, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.125% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of a 30-day LIBOR draw at a rate of 0.18% (subject to the additional spread mentioned above).
[3]	Piedmont may select from multiple interest rate options with each draw, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.175% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of 30-day LIBOR draws at a rate of 0.18% (subject to the additional spread mentioned above).

Debt_Details

Debt (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015		Apr. 10, 2015	Dec. 31, 2014		Jun. 27, 2014
	period
Debt Instrument [Line Items]
Weighted Average Rate	3.31%	[1],[2]
Amount Outstanding	$2,326,109,000	[2]		$2,277,589,000	[2]
Maximum extension period	1 year
Number of extension periods	2
Extension period	6 months
$170 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Rate	1.13%
Basis spread on variable rate	1.00%
LIBOR rate in effect	0.18%
Secured Debt [Member]
Debt Instrument [Line Items]
Weighted Average Rate	5.56%	[1],[2]
Amount Outstanding	448,791,000	[2]		449,045,000	[2]
Secured Debt [Member] | Fixed-Rate $105 Million Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	105,000,000
Rate	5.29%	[1],[3]
Amount Outstanding	105,000,000	[3]		105,000,000	[3]
Secured Debt [Member] | Fixed-Rate $105 Million Loan [Member] | Subsequent Event [Member]
Debt Instrument [Line Items]
Amount repaid			105,000,000
Secured Debt [Member] | Fixed-Rate $125 Million Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	125,000,000
Rate	5.50%	[1],[4]
Amount Outstanding	125,000,000	[4]		125,000,000	[4]
Secured Debt [Member] | Fixed-Rate $42.5 Million Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	42,500,000
Rate	5.70%	[1]
Amount Outstanding	42,525,000			42,525,000
Secured Debt [Member] | WDC Mortgage Notes $140 Million[Member]
Debt Instrument [Line Items]
Face amount of debt instrument	140,000,000
Rate	5.76%	[1]
Amount Outstanding	140,000,000			140,000,000
Secured Debt [Member] | Mortgage Loan Maturing September 1, 2021 [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	35,000,000					35,000,000
Rate	5.55%	[1],[5]
Amount Outstanding	36,266,000	[5]		36,520,000	[5]
Effective interest rate	3.75%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Weighted Average Rate	2.78%	[1],[2]
Amount Outstanding	1,877,318,000	[2]		1,828,544,000	[2]
Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2020 [Member]
Debt Instrument [Line Items]
Amount Outstanding	298,996,000	[6]		298,944,000	[6]
Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2020 [Member] | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Effective interest rate	3.35%
Unsecured Debt [Member] | $500 Million Unsecured Line of Credit [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	500,000,000
Amount Outstanding	363,000,000	[7],[8]		434,000,000	[7],[8]
Basis spread on variable rate	1.18%
LIBOR rate in effect	0.18%
Unsecured Debt [Member] | $500 Million Unsecured Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.18%	[1],[7]
Unsecured Debt [Member] | $350 Million Senior Notes [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	350,000,000
Rate	3.40%	[1],[9]
Amount Outstanding	348,831,000	[9]		348,800,000	[9]
Effective interest rate	3.45%
Unsecured Debt [Member] | $300 million Unsecured 2013 Term Loan Maturing 2019 [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	300,000,000
Amount Outstanding	300,000,000	[10]		300,000,000	[10]
Unsecured Debt [Member] | $300 million Unsecured 2013 Term Loan Maturing 2019 [Member] | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Effective interest rate	2.78%
Unsecured Debt [Member] | $300 million Unsecured 2013 Term Loan Maturing 2019 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.20%	[1],[10]
Unsecured Debt [Member] | $400 Million Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	400,000,000
Rate	4.45%	[1],[11]
Amount Outstanding	396,914,000	[11]		396,832,000	[11]
Unsecured Debt [Member] | $50 Million Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	50,000,000
Amount Outstanding	0			49,968,000
Unsecured Debt [Member] | $50 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.15%	[1]
Unsecured Debt [Member] | $170 Million Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	170,000,000
Amount Outstanding	169,577,000	[12]		0	[12]
Unsecured Debt [Member] | $170 Million Unsecured Term Loan [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.13%	[1],[12]
Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2016 [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	300,000,000
Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2016 [Member] | Interest Rate Swap [Member]
Debt Instrument [Line Items]
Effective interest rate	2.39%
Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2016 [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate	1.15%	[1],[6]
Senior Notes [Member] | $350 Million Senior Notes [Member]
Debt Instrument [Line Items]
Effective interest rate	3.43%
Senior Notes [Member] | $400 Million Unsecured Senior Notes [Member]
Debt Instrument [Line Items]
Face amount of debt instrument	$400,000,000
Effective interest rate	4.48%
Effective interest rate	4.10%
[1]	Other than the $35 Million Fixed-Rate Loan, all of Piedmont’s outstanding debt as of March 31, 2015 and December 31, 2014 is interest-only.
[2]	Weighted average is based on contractual balance of outstanding debt and interest rates in the table as of March 31, 2015.
[3]	On April 10, 2015, Piedmont repaid in full the balance on the $105 Million Fixed-Rate Loan.
[4]	Property collateralized pool includes 1430 Enclave Parkway in Houston, Texas, Windy Point I and II in Schaumburg, Illinois, and 1055 East Colorado Boulevard in Pasadena, California.
[5]	The $35 Million Fixed-Rate Loan has a contractual fixed rate of 5.55% ; however, the amortization of the premium recorded in order to adjust the note to its estimated fair value, results in an effective interest rate of 3.75%.
[6]	The $300 Million Unsecured 2011 Term Loan 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, the rate on this facility to 2.39% through the original maturity date of November 22, 2016 and 3.35% from November 22, 2016 to January 15, 2020.
[7]	Piedmont may select from multiple interest rate options with each draw, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.175% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of 30-day LIBOR draws at a rate of 0.18% (subject to the additional spread mentioned above).
[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 August 21, 2017) provided Piedmont is not then in default and upon payment of extension fees.
[9]	The $350 Million Senior Notes have a fixed coupon rate of 3.40%, however, as a result of the issuance of the notes at a discount, Piedmont recognizes an effective interest rate on this debt issuance of 3.45%. After consideration of the impact of settled interest rate swap agreements, in addition to the issuance discount, the effective interest rate on this debt is 3.43%.
[10]	The $300 Million Unsecured 2013 Term Loan has a stated variable rate; however, Piedmont entered into interest rate swap agreements which effectively fix, absent any changes to Piedmont's credit rating, the rate on this facility to 2.78% .
[11]	The $400 Million Senior Notes have a fixed coupon rate of 4.45%, however, as a result of the issuance of the notes at a discount, Piedmont recognizes an effective interest rate on this debt issuance of 4.48%. After consideration of the impact of settled interest rate swap agreements, in addition to the issuance discount, the effective interest rate on this debt is 4.10%.
[12]	Piedmont may select from multiple interest rate options, including the prime rate and various-length LIBOR locks. All LIBOR selections are subject to an additional spread (1.125% as of March 31, 2015) over the selected rate based on Piedmont’s current credit rating. The outstanding balance as of March 31, 2015 consisted of a 30-day LIBOR draw at a rate of 0.18% (subject to the additional spread mentioned above).

Derivative_Instruments_Details

Derivative Instruments (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Derivative [Line Items]
Maximum period of extension term	131 months
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Gross derivative assets	$520,000		$430,000
Gross derivative liabilities	-19,416,000		-6,417,000
Net derivative liability	-18,896,000		-5,987,000
Loss to be reclassified from accumulated other comprehensive loss to interest expense over next twelve months	5,700,000
Interest Rate Swap [Member] | Interest Expense [Member]
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Amount of gain/(loss) recognized in OCI on derivative	-15,205,000	-9,886,000
Amount of previously recorded loss reclassified from accumulated OCI into interest expense	1,467,000	1,170,000
Credit Risk Contract [Member]
Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract]
Assets needed for immediate settlement, aggregate fair value	20,300,000
Unsecured Debt [Member] | $500 Million Unsecured Line of Credit [Member]
Derivative [Line Items]
Face amount of debt instrument	500,000,000
Unsecured Debt [Member] | $170 Million Unsecured Term Loan [Member]
Derivative [Line Items]
Face amount of debt instrument	170,000,000
Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2016 [Member]
Derivative [Line Items]
Face amount of debt instrument	300,000,000
Unsecured Debt [Member] | $300 million Unsecured 2013 Term Loan Maturing 2019 [Member]
Derivative [Line Items]
Face amount of debt instrument	300,000,000
Debt [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Total notional value	1,400,000,000
Debt [Member] | Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Total notional value	500,000,000
Debt [Member] | Forward Starting Interest Rate Swap 4 through 8 [Member]
Derivative [Line Items]
Total notional value	250,000,000
Number of Swap Agreements	4
Debt [Member] | Forward Starting Interest Rate Swap 9 through 12 [Member]
Derivative [Line Items]
Total notional value	250,000,000
Number of Swap Agreements	4
Debt [Member] | Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2016 [Member] | Interest Rate Swap 1 through 4 [Member]
Derivative [Line Items]
Total notional value	300,000,000
Number of Swap Agreements	4
Debt [Member] | Unsecured Debt [Member] | $300 million Unsecured 2013 Term Loan Maturing 2019 [Member] | Interest Rate Swap 5 through 8 [Member]
Derivative [Line Items]
Total notional value	200,000,000
Number of Swap Agreements	4
Debt [Member] | Unsecured Debt [Member] | $300 million Unsecured 2013 Term Loan Maturing 2019 [Member] | Interest Rate Swap 9 through 10 [Member]
Derivative [Line Items]
Total notional value	100,000,000
Number of Swap Agreements	2
Debt [Member] | Unsecured Debt [Member] | $300 Million 2011 Unsecured Term Loan Maturing 2020 [Member] | Forward Starting Interest Rate Swap 1 through 3 [Member]
Derivative [Line Items]
Total notional value	$300,000,000
Number of Swap Agreements	3

Variable_Interest_Entities_and2

Variable Interest Entities and Equity Participation Rights (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Variable Interest Entity [Line Items]
Payment to settle redemption option	$4,000,000	$0
Medici Atlanta LLC [Member]
Variable Interest Entity [Line Items]
Payment to settle redemption option	4,000,000
Eye Street 1201 NW Associates LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	49.50%
Net Carrying Amount	-2,500,000		-2,800,000
Variable interest entity, cash flow percent entitled to entity	100.00%
Eye Street 1225 NW Associates LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	49.50%
Net Carrying Amount	600,000		-1,100,000
Variable interest entity, cash flow percent entitled to entity	100.00%
Piedmont 500 W. Monroe Fee LLC [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	100.00%
Net Carrying Amount	245,700,000		245,300,000
Land Parcel Adjacent to 400 Town Park Building [Member]
Variable Interest Entity [Line Items]
Piedmont’s % Ownership of Entity	100.00%
Net Carrying Amount	$7,900,000		$7,900,000

Fair_Value_Measurement_of_Fina2

Fair Value Measurement of Financial Instruments (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	$520		$430
Interest rate swap liability	19,416		6,417
Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	7,479	[1]	12,306	[1]
Tenant receivables, net	30,132	[1]	27,711	[1]
Restricted cash and escrows	671	[1]	5,679	[1]
Accounts payable and accrued expenses	16,098	[1]	14,395	[1]
Debt	2,326,109		2,277,589
Interest Rate Swap [Member] | Carrying Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	520		430
Interest rate swap liability	19,416		6,417
Level 1 [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	7,479	[1]	12,306	[1]
Tenant receivables, net	30,132	[1]	27,711	[1]
Restricted cash and escrows	671	[1]	5,679	[1]
Accounts payable and accrued expenses	16,098	[1]	14,395	[1]
Level 2 [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	2,373,488		2,314,020
Level 2 [Member] | Interest Rate Swap [Member] | Estimated Fair Value [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps	520		430
Interest rate swap liability	$19,416		$6,417
[1]	For the periods presented, the carrying value of these financial instruments approximates estimated fair value due to their short-term maturity.

Commitments_and_Contingencies_

Commitments and Contingencies (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
	category
Loss Contingencies [Line Items]
Number of tenant and building improvement categories	2
Letters of credit outstanding	$400,000
Letter of credit, renewal period	1 year
Unsecured Debt [Member] | $500 Million Unsecured Line of Credit [Member]
Loss Contingencies [Line Items]
Face amount of debt instrument	500,000,000
Tenant Audits and Disputes [Member]
Loss Contingencies [Line Items]
Tenant audit dispute expense	0	300,000
Non-Incremental Capital Expenditures [Member]
Loss Contingencies [Line Items]
Potential obligations for tenant improvements	46,100,000
Incremental Capital Expenditures [Member]
Loss Contingencies [Line Items]
Potential obligations for tenant improvements	$23,800,000
Non-Incremental Capital Expenditures [Member]
Loss Contingencies [Line Items]
Period for commitments for funding non-incremental capital expenditures	3 years
Maximum [Member] | Non-Incremental Capital Expenditures [Member]
Loss Contingencies [Line Items]
Period for commitments for funding non-incremental capital expenditures			5 years

Property_Dispositions_and_Disc

Property Dispositions and Discontinued Operations (Assets Held for Sale) (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total real estate assets held for sale, net		$14,544
Total other assets held for sale, net	0	1,264
3900 Dallas Parkway Building [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total real estate assets held for sale, net	0	14,544
Straight-line rent receivables	0	768
Deferred lease costs, less accumulated amortization of $1,552 as of December 31, 2014	0	496
Accumulated amortization on deferred lease costs	0	1,552
Total other assets held for sale, net	0	1,264
Land [Member] | 3900 Dallas Parkway Building [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	0	1,517
Building and Building Improvements [Member] | 3900 Dallas Parkway Building [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate assets held for sale, net:	0	13,027
Accumulated depreciation (building improvements)	$0	$10,342

Assets_Held_for_Sale_and_Disco2

Assets Held for Sale and Discontinued Operations (Details) (USD $)	3 Months Ended		0 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 19, 2014	Apr. 30, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds	$25,803,000	$22,322,000
Loss on sale of real estate assets, net	0	-106,000
Revenues:
Rental income	0	1,174,000
Tenant reimbursements	0	112,000
Revenue	0	1,286,000
Expenses:
Property operating costs	0	505,000
Depreciation	0	83,000
Amortization	0	223,000
General and administrative	0	3,000
Expenses	0	814,000
Other income/(expense)
Other income/(expense)	0	-6,000
Operating income, excluding gain on sale	0	466,000
Income from discontinued operations	0	360,000
3900 Dallas Parkway Building [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales price of building	26,200,000
Gain/(Loss) on Sale	10,100,000
Net Sales Proceeds	25,800,000
11107 and 11109 Sunset Hills Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds			22,326,000
Loss on sale of real estate assets, net			-102,000
1441 West Long Lake Road [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds				7,202,000
Loss on sale of real estate assets, net				562,000
4685 Investment Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net Sales Proceeds				11,198,000
Loss on sale of real estate assets, net				$747,000

Stock_Based_Compensation_Rollf

Stock Based Compensation (Rollforward of Deferred Stock Awards) (Details) (Stock Awards [Member], USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Unvested Deferred Stock Awards, Beginning of period (in shares)	506,404
Deferred Stock Awards Granted (in shares)	0
Adjustment to Estimated Future Grants of Performance Share Awards (in shares)	-15,413
Deferred Stock Awards Vested (in shares)	-20,976
Deferred Stock Awards Forfeited (in shares)	0
Unvested Deferred Stock Awards, End of period (in shares)	470,015
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Roll Forward]
Unvested Deferred Stock Awards, Weighted-Average Grant Date Fair Value, Beginning of period (in dollars per share)	$18.12
Deferred Stock Awards Granted, Weighted-Average Grant Date Fair Value (in dollars per share)	$0	$16.45
Adjustment to Estimated Future Grants of Performance Share Awards (Weighted-Average Grant Date Fair Value, in dollars per share)	$18.51
Deferred Stock Awards Vested, Weighted-Average Grant Date Fair Value (in dollars per share)	$16.48
Deferred Stock Awards Forfeited, Weighted-Average Grant Date Fair Value (in dollars per share)	$0
Unvested Deferred Stock Awards, Weighted-Average Grant Date Fair Value, End of period (in dollars per share)	$18.18

Stock_Based_Compensation_Addit

Stock Based Compensation (Additional Information Regarding Stock Award Activity) (Details) (Stock Awards [Member], USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-Average Grant Date Fair Value of Shares Granted During the Period (per share)	$0		$16.45
Total Grant Date Fair Value of Shares Vested During the Period	$346		$4
Share-based Liability Awards Paid During the Period	$0	[1]	$0	[1]
[1]	Amount reflects the issuance of performance share awards during the period.

Stock_Based_Compensation_Outst

Stock Based Compensation (Outstanding Employee Deferred Stock Awards) (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014	Apr. 04, 2012		Apr. 02, 2013		Jan. 03, 2014		9-May-14
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grant Date Fair Value	$18.18		$18.12
Unvested Shares	470,015		506,404
Stock Awards 1, Granted April 4, 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted				169,128	[1]
Grant Date Fair Value				$17.53
Of the shares granted, % vested	25.00%
Of the shares granted, % expected to vest in one year	25.00%
Of the shares granted, % expected to vest in two years	25.00%
Of the shares granted, % expected to vest in three years	25.00%
Unvested Shares	53,868
Stock Awards, Granted April 2, 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted						132,826	[1]
Grant Date Fair Value						$19.47
Of the shares granted, % vested	25.00%
Of the shares granted, % expected to vest in one year	25.00%
Of the shares granted, % expected to vest in two years	25.00%
Of the shares granted, % expected to vest in three years	25.00%
Unvested Shares	76,156
Stock Awards 2, Granted April 2, 2013 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted						0	[1]
Grant Date Fair Value						$18.91
Unvested Shares	0	[2]
Stock Awards, Granted January 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted								95,476	[1]
Grant Date Fair Value								$16.45
Of the shares granted, % vested	20.00%
Of the shares granted, % expected to vest in one year	20.00%
Of the shares granted, % expected to vest in two years	20.00%
Of the shares granted, % expected to vest in three years	20.00%
Of the shares granted, % expected to vest in four years	20.00%
Unvested Shares	82,673
Stock Awards, Granted May 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted										179,897	[1]
Grant Date Fair Value										$18.47
Of the shares granted, % vested	25.00%
Of the shares granted, % expected to vest in one year	25.00%
Of the shares granted, % expected to vest in two years	25.00%
Of the shares granted, % expected to vest in three years	25.00%
Unvested Shares	144,287
Stock Awards 2, Granted May 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Net Shares Granted										0	[1]
Grant Date Fair Value										$18.51
Unvested Shares	113,031	[3]
[1]	Amounts reflect the total grant to employees, net of shares surrendered upon vesting to satisfy required minimum tax withholding obligations through March 31, 2015.
[2]	Estimated based on Piedmont's cumulative total stockholder return ("TSR") for the respective performance period through March 31, 2015. As of March 31, 2015, Piedmont's TSR for the fiscal year 2013-2015 performance share program was below threshold. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.
[3]	Estimated based on Piedmont's cumulative TSR for the respective performance period through March 31, 2015. Share estimates are subject to change in future periods based on both Piedmont's and its peers' stock performance and dividends paid.

Stock_Based_Compensation_Narra

Stock Based Compensation (Narrative) (Details) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Compensation expense related to stock awards	$0.90	$0.60
Amortization of unvested shares	0.8	0.6
Total shares issued to employees, directors, and officers	15,418
Unrecognized compensation cost related to nonvested	$2.30
Unrecognized compensation cost related to nonvested, weighted-average vesting period (in years)	1 year

Earnings_Per_Share_Details

Earnings Per Share (Details)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Weighted-average common shares – basic	154,339,029	154,849,378
Deferred stock awards (in shares)	241,000	176,000
Weighted-average common shares outstanding – diluted	154,580,335	155,024,545

Guarantor_and_NonGuarantor_Fin2

Guarantor and Non-Guarantor Financial Information - Condensed Consolidated Balance Sheets (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets:
Land	$707,340	$702,800
Buildings and improvements, less accumulated depreciation	3,234,495	3,224,178
Intangible lease assets, less accumulated amortization	69,254	70,177
Construction in progress	83,853	63,393
Total real estate assets held for sale, net		14,544
Total real estate assets	4,094,942	4,075,092
Investments in and amounts due from unconsolidated joint ventures	7,820	7,798
Cash and cash equivalents	7,479	12,306	9,271	6,973
Tenant and straight-line rent receivables, net	205,472	197,243
Advances to affiliates	0	0
Investment in subsidiary	0	0
Notes receivable	0	0
Prepaid expenses, restricted cash, escrows, and other assets	27,550	33,499
Goodwill	180,097	180,097
Interest rate swaps	520	430
Deferred financing costs, net	7,391	7,667
Deferred lease costs, net	288,591	280,105
Other assets held for sale	0	1,264
Total assets	4,819,862	4,795,501
Liabilities:
Debt, net	2,326,109	2,277,589
Accounts payable, accrued expenses, and accrued capital expenditures	119,466	133,988
Advances from affiliates	0	0
Deferred income	25,970	22,215
Intangible lease liabilities, net	42,978	43,277
Interest rate swaps	19,416	6,417
Total liabilities	2,533,939	2,483,486
Stockholders’ Equity:
Common stock	1,543	1,543
Additional paid-in capital	3,667,574	3,666,182
Cumulative distributions in excess of earnings	-1,378,786	-1,365,620
Other comprehensive income	-5,437	8,301
Piedmont stockholders’ equity	2,284,894	2,310,406
Noncontrolling interest	1,029	1,609
Total stockholders’ equity	2,285,923	2,312,015		2,461,159
Total liabilities and stockholders’ equity	4,819,862	4,795,501
Issuer [Member]
Assets:
Land	81,406	81,406
Buildings and improvements, less accumulated depreciation	438,933	442,034
Intangible lease assets, less accumulated amortization	1,676	1,812
Construction in progress	3,032	1,355
Total real estate assets held for sale, net		14,544
Total real estate assets	525,047	541,151
Investments in and amounts due from unconsolidated joint ventures	7,820	7,798
Cash and cash equivalents	3,879	8,143	6,132	3,261
Tenant and straight-line rent receivables, net	37,756	37,238
Advances to affiliates	6,142,933	6,084,243
Investment in subsidiary	0	0
Notes receivable	161,350	161,350
Prepaid expenses, restricted cash, escrows, and other assets	6,129	10,912
Goodwill	180,097	180,097
Interest rate swaps	520	430
Deferred financing costs, net	7,023	7,242
Deferred lease costs, net	31,445	31,340
Other assets held for sale		1,264
Total assets	7,103,999	7,071,208
Liabilities:
Debt, net	1,901,208	1,852,434
Accounts payable, accrued expenses, and accrued capital expenditures	16,732	19,403
Advances from affiliates	392,696	376,122
Deferred income	5,150	4,998
Intangible lease liabilities, net	0	0
Interest rate swaps	19,416	6,417
Total liabilities	2,335,202	2,259,374
Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	3,842,399	3,874,757
Cumulative distributions in excess of earnings	931,835	928,776
Other comprehensive income	-5,437	8,301
Piedmont stockholders’ equity	4,768,797	4,811,834
Noncontrolling interest	0	0
Total stockholders’ equity	4,768,797	4,811,834
Total liabilities and stockholders’ equity	7,103,999	7,071,208
Guarantor [Member]
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
Total real estate assets held for sale, net		0
Total real estate assets	0	0
Investments in and amounts due from unconsolidated joint ventures	0	0
Cash and cash equivalents	250	1,790	150	150
Tenant and straight-line rent receivables, net	0	0
Advances to affiliates	1,284,521	1,282,443
Investment in subsidiary	3,846,399	3,878,811
Notes receivable	0	0
Prepaid expenses, restricted cash, escrows, and other assets	116	0
Goodwill	0	0
Interest rate swaps	0	0
Deferred financing costs, net	0	0
Deferred lease costs, net	0	0
Other assets held for sale		0
Total assets	5,131,286	5,163,044
Liabilities:
Debt, net	0	0
Accounts payable, accrued expenses, and accrued capital expenditures	674	465
Advances from affiliates	4,909,707	4,909,362
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps	0	0
Total liabilities	4,910,381	4,909,827
Stockholders’ Equity:
Common stock	1,543	1,543
Additional paid-in capital	3,670,447	3,670,236
Cumulative distributions in excess of earnings	-3,451,085	-3,418,562
Other comprehensive income	0	0
Piedmont stockholders’ equity	220,905	253,217
Noncontrolling interest	0	0
Total stockholders’ equity	220,905	253,217
Total liabilities and stockholders’ equity	5,131,286	5,163,044
Non-Guarantor Subsidiaries [Member]
Assets:
Land	625,934	621,394
Buildings and improvements, less accumulated depreciation	2,795,862	2,782,444
Intangible lease assets, less accumulated amortization	67,578	68,365
Construction in progress	80,821	62,038
Total real estate assets held for sale, net		0
Total real estate assets	3,570,195	3,534,241
Investments in and amounts due from unconsolidated joint ventures	0	0
Cash and cash equivalents	3,350	2,373	2,989	3,562
Tenant and straight-line rent receivables, net	167,716	160,005
Advances to affiliates	0	0
Investment in subsidiary	191	192
Notes receivable	23,890	23,890
Prepaid expenses, restricted cash, escrows, and other assets	22,567	23,541
Goodwill	0	0
Interest rate swaps	0	0
Deferred financing costs, net	368	425
Deferred lease costs, net	257,146	248,765
Other assets held for sale		0
Total assets	4,045,423	3,993,432
Liabilities:
Debt, net	610,141	610,395
Accounts payable, accrued expenses, and accrued capital expenditures	103,322	115,074
Advances from affiliates	2,185,841	2,138,140
Deferred income	20,820	17,217
Intangible lease liabilities, net	42,978	43,277
Interest rate swaps	0	0
Total liabilities	2,963,102	2,924,103
Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	1,318	192
Cumulative distributions in excess of earnings	1,079,974	1,067,528
Other comprehensive income	0	0
Piedmont stockholders’ equity	1,081,292	1,067,720
Noncontrolling interest	1,029	1,609
Total stockholders’ equity	1,082,321	1,069,329
Total liabilities and stockholders’ equity	4,045,423	3,993,432
Eliminations [Member]
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
Total real estate assets held for sale, net		0
Total real estate assets	-300	-300
Investments in and amounts due from unconsolidated joint ventures	0	0
Cash and cash equivalents	0	0	0	0
Tenant and straight-line rent receivables, net	0	0
Advances to affiliates	-7,427,454	-7,366,686
Investment in subsidiary	-3,846,590	-3,879,003
Notes receivable	-185,240	-185,240
Prepaid expenses, restricted cash, escrows, and other assets	-1,262	-954
Goodwill	0	0
Interest rate swaps	0	0
Deferred financing costs, net	0	0
Deferred lease costs, net	0	0
Other assets held for sale		0
Total assets	-11,460,846	-11,432,183
Liabilities:
Debt, net	-185,240	-185,240
Accounts payable, accrued expenses, and accrued capital expenditures	-1,262	-954
Advances from affiliates	-7,488,244	-7,423,624
Deferred income	0	0
Intangible lease liabilities, net	0	0
Interest rate swaps	0	0
Total liabilities	-7,674,746	-7,609,818
Stockholders’ Equity:
Common stock	0	0
Additional paid-in capital	-3,846,590	-3,879,003
Cumulative distributions in excess of earnings	60,490	56,638
Other comprehensive income	0	0
Piedmont stockholders’ equity	-3,786,100	-3,822,365
Noncontrolling interest	0	0
Total stockholders’ equity	-3,786,100	-3,822,365
Total liabilities and stockholders’ equity	($11,460,846)	($11,432,183)

Guarantor_and_NonGuarantor_Fin3

Guarantor and Non-Guarantor Financial Information - Condensed Consolidated Statements of Income (Details) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Revenues:
Rental income	$117,807	$110,904
Tenant reimbursements	31,390	24,929
Property management fee revenue	562	487
Total revenues	149,759	136,320
Expenses:
Property operating costs	64,236	58,271
Depreciation	36,232	33,644
Amortization	14,670	14,573
General and administrative	6,407	4,555
Operating Expenses	121,545	111,043
Real estate operating income	28,214	25,277
Other income (expense):
Interest expense	-19,016	-18,926
Other income/(expense)	-181	-90
Net recoveries from casualty events and litigation settlements	0	3,042
Equity in income/(loss) of unconsolidated joint ventures	159	-266
Nonoperating Income (Expense)	-19,038	-16,240
Income from continuing operations	9,176	9,037
Discontinued operations:
Operating income	0	466
Loss on sale of real estate assets, net	0	-106
Income from discontinued operations	0	360
Gain on sale of real estate assets, net	10,073	0
Net income	19,249	9,397
Less: Net income attributable to noncontrolling interest	-4	-4
Net income attributable to Piedmont	19,245	9,393	43,348
Issuer [Member]
Revenues:
Rental income	18,937	17,400
Tenant reimbursements	4,246	3,861
Property management fee revenue	0	0
Total revenues	23,183	21,261
Expenses:
Property operating costs	10,661	10,044
Depreciation	5,803	5,840
Amortization	1,254	1,111
General and administrative	6,200	4,469
Operating Expenses	23,918	21,464
Real estate operating income	-735	-203
Other income (expense):
Interest expense	-13,188	-9,120
Other income/(expense)	2,766	2,762
Net recoveries from casualty events and litigation settlements		1,351
Equity in income/(loss) of unconsolidated joint ventures	159	-266
Nonoperating Income (Expense)	-10,263	-5,273
Income from continuing operations	-10,998	-5,476
Discontinued operations:
Operating income	0	480
Loss on sale of real estate assets, net		-106
Income from discontinued operations	0	374
Gain on sale of real estate assets, net	10,073
Net income	-925	-5,102
Less: Net income attributable to noncontrolling interest	0	0
Net income attributable to Piedmont	-925	-5,102
Guarantor [Member]
Revenues:
Rental income	0	0
Tenant reimbursements	0	0
Property management fee revenue	0	0
Total revenues	0	0
Expenses:
Property operating costs	0	0
Depreciation	0	0
Amortization	0	0
General and administrative	111	77
Operating Expenses	111	77
Real estate operating income	-111	-77
Other income (expense):
Interest expense	0	0
Other income/(expense)	0	35
Net recoveries from casualty events and litigation settlements		0
Equity in income/(loss) of unconsolidated joint ventures	0	0
Nonoperating Income (Expense)	0	35
Income from continuing operations	-111	-42
Discontinued operations:
Operating income	0	0
Loss on sale of real estate assets, net		0
Income from discontinued operations	0	0
Gain on sale of real estate assets, net	0
Net income	-111	-42
Less: Net income attributable to noncontrolling interest	0	0
Net income attributable to Piedmont	-111	-42
Non-Guarantor Subsidiaries [Member]
Revenues:
Rental income	99,577	95,157
Tenant reimbursements	27,272	21,179
Property management fee revenue	4,439	4,171
Total revenues	131,288	120,507
Expenses:
Property operating costs	58,494	53,878
Depreciation	30,429	27,804
Amortization	13,416	13,462
General and administrative	7,724	5,961
Operating Expenses	110,063	101,105
Real estate operating income	21,225	19,402
Other income (expense):
Interest expense	-8,949	-12,939
Other income/(expense)	174	246
Net recoveries from casualty events and litigation settlements		1,691
Equity in income/(loss) of unconsolidated joint ventures	0	0
Nonoperating Income (Expense)	-8,775	-11,002
Income from continuing operations	12,450	8,400
Discontinued operations:
Operating income	0	-14
Loss on sale of real estate assets, net		0
Income from discontinued operations	0	-14
Gain on sale of real estate assets, net	0
Net income	12,450	8,386
Less: Net income attributable to noncontrolling interest	-4	-4
Net income attributable to Piedmont	12,446	8,382
Eliminations [Member]
Revenues:
Rental income	-707	-1,653
Tenant reimbursements	-128	-111
Property management fee revenue	-3,877	-3,684
Total revenues	-4,712	-5,448
Expenses:
Property operating costs	-4,919	-5,651
Depreciation	0	0
Amortization	0	0
General and administrative	-7,628	-5,952
Operating Expenses	-12,547	-11,603
Real estate operating income	7,835	6,155
Other income (expense):
Interest expense	3,121	3,133
Other income/(expense)	-3,121	-3,133
Net recoveries from casualty events and litigation settlements		0
Equity in income/(loss) of unconsolidated joint ventures	0	0
Nonoperating Income (Expense)	0	0
Income from continuing operations	7,835	6,155
Discontinued operations:
Operating income	0	0
Loss on sale of real estate assets, net		0
Income from discontinued operations	0	0
Gain on sale of real estate assets, net	0
Net income	7,835	6,155
Less: Net income attributable to noncontrolling interest	0	0
Net income attributable to Piedmont	$7,835	$6,155

Guarantor_and_NonGuarantor_Fin4

Guarantor and Non-Guarantor Financial Information - Condensed Consolidated Statements of Cash Flows (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	$43,630	$70,053
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	-81,358	-27,587
Redemption of noncontrolling interest in unconsolidated variable interest entity	-4,000	0
Net sales proceeds from wholly-owned properties	25,803	22,322
Deferred lease costs paid	-4,414	-4,180
Net cash used in investing activities	-63,969	-9,445
Cash Flows from Financing Activities:
Deferred financing costs paid	-242	-454
Proceeds from debt	257,575	764,564
Repayments of debt	-209,254	-737,000
Net costs of issuance of common stock	-90	0
Repurchases of common stock as part of announced plan	0	-54,515
(Distributions to)/repayments from affiliates	0	0
Dividends paid and discount on dividend reinvestments	-32,477	-30,905
Net cash provided by/(used in) financing activities	15,512	-58,310
Net (decrease)/increase in cash and cash equivalents	-4,827	2,298
Cash and cash equivalents, beginning of period	12,306	6,973
Cash and cash equivalents, end of period	7,479	9,271
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	-6,974	21,395
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	-5,091	-6,875
Redemption of noncontrolling interest in unconsolidated variable interest entity	0
Net sales proceeds from wholly-owned properties	25,803	22,322
Deferred lease costs paid	-846	-720
Net cash used in investing activities	19,866	14,727
Cash Flows from Financing Activities:
Deferred financing costs paid	-242	-454
Proceeds from debt	257,575	764,564
Repayments of debt	-209,000	-162,000
Net costs of issuance of common stock	0
Repurchases of common stock as part of announced plan		0
(Distributions to)/repayments from affiliates	-65,489	-635,361
Dividends paid and discount on dividend reinvestments	0	0
Net cash provided by/(used in) financing activities	-17,156	-33,251
Net (decrease)/increase in cash and cash equivalents	-4,264	2,871
Cash and cash equivalents, beginning of period	8,143	3,261
Cash and cash equivalents, end of period	3,879	6,132
Guarantor [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	426	594
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Redemption of noncontrolling interest in unconsolidated variable interest entity	0
Net sales proceeds from wholly-owned properties	0	0
Deferred lease costs paid	0	0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities:
Deferred financing costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Net costs of issuance of common stock	-90
Repurchases of common stock as part of announced plan		-54,515
(Distributions to)/repayments from affiliates	30,601	84,826
Dividends paid and discount on dividend reinvestments	-32,477	-30,905
Net cash provided by/(used in) financing activities	-1,966	-594
Net (decrease)/increase in cash and cash equivalents	-1,540	0
Cash and cash equivalents, beginning of period	1,790	150
Cash and cash equivalents, end of period	250	150
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	42,343	41,908
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	-76,267	-20,712
Redemption of noncontrolling interest in unconsolidated variable interest entity	-4,000
Net sales proceeds from wholly-owned properties	0	0
Deferred lease costs paid	-3,568	-3,460
Net cash used in investing activities	-83,835	-24,172
Cash Flows from Financing Activities:
Deferred financing costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	-254	-575,000
Net costs of issuance of common stock	0
Repurchases of common stock as part of announced plan		0
(Distributions to)/repayments from affiliates	42,723	556,691
Dividends paid and discount on dividend reinvestments	0	0
Net cash provided by/(used in) financing activities	42,469	-18,309
Net (decrease)/increase in cash and cash equivalents	977	-573
Cash and cash equivalents, beginning of period	2,373	3,562
Cash and cash equivalents, end of period	3,350	2,989
Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net Cash Provided by Operating Activities	7,835	6,156
Cash Flows from Investing Activities:
Investment in real estate assets and real estate related intangibles, net of accruals	0	0
Redemption of noncontrolling interest in unconsolidated variable interest entity	0
Net sales proceeds from wholly-owned properties	0	0
Deferred lease costs paid	0	0
Net cash used in investing activities	0	0
Cash Flows from Financing Activities:
Deferred financing costs paid	0	0
Proceeds from debt	0	0
Repayments of debt	0	0
Net costs of issuance of common stock	0
Repurchases of common stock as part of announced plan		0
(Distributions to)/repayments from affiliates	-7,835	-6,156
Dividends paid and discount on dividend reinvestments	0	0
Net cash provided by/(used in) financing activities	-7,835	-6,156
Net (decrease)/increase in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	$0	$0

Subsequent_Events_Details

Subsequent Events (Details) (Subsequent Event [Member], USD $)	0 Months Ended
In Millions, except Per Share data, unless otherwise specified	Apr. 28, 2015	Apr. 15, 2015	Apr. 29, 2015
		sqft	sqft
Subsequent Event [Line Items]
Dividends declared (in dollars per share)	$0.21
Copper Ridge Center [Member]
Subsequent Event [Line Items]
Square footage of real estate property		268,000
Percentage leased		87.00%
5601 Headquarters Drive [Member]
Subsequent Event [Line Items]
Square footage of real estate property	166,000
Percentage leased	100.00%
River Corporate Center [Member]
Subsequent Event [Line Items]
Square footage of real estate property			133,000
Percentage leased			100.00%
Sales price of property dispositions			$24.60
Sales price per square foot			185