Equity Commonwealth (EQC) 10-Q 5 Nov 15 2015 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 31, 2015
Document and Entity Information
Entity Registrant Name	Equity Commonwealth
Entity Central Index Key	803,649
Document Type	10-Q
Document Period End Date	Sep. 30, 2015
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		126,349,914
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Real estate properties:
Land	$ 413,281	$ 714,238
Buildings and improvements	3,559,060	5,014,205
Total real estate properties, at cost, gross	3,972,341	5,728,443
Accumulated depreciation	(884,183)	(1,030,445)
Total real estate properties, at cost, net	3,088,158	4,697,998
Properties held for sale	112,150	0
Acquired real estate leases, net	99,017	198,287
Cash and cash equivalents	1,649,162	364,516
Restricted cash	28,463	32,257
Rents receivable, net of allowance for doubtful accounts of $9,281 and $6,565, respectively	184,679	248,101
Other assets, net	162,614	220,480
Total assets	5,324,243	5,761,639
LIABILITIES AND SHAREHOLDERS’ EQUITY
Senior unsecured debt, net	1,460,360	1,598,416
Mortgage notes payable, net	367,713	609,249
Liabilities related to properties held for sale	1,909	0
Accounts payable and accrued expenses	121,697	162,204
Assumed real estate lease obligations, net	4,890	26,784
Rent collected in advance	29,744	31,359
Security deposits	10,722	14,044
Total liabilities	1,997,035	2,442,056
Preferred shares of beneficial interest, $0.01 par value: 50,000,000 shares authorized;
Common shares of beneficial interest, $0.01 par value: 350,000,000 shares authorized; 126,349,914 and 129,607,279 shares issued and outstanding, respectively	1,263	1,296
Additional paid in capital	4,410,951	4,487,133
Cumulative net income	2,290,564	2,233,852
Cumulative other comprehensive loss	(5,142)	(53,216)
Cumulative common distributions	(3,111,868)	(3,111,868)
Cumulative preferred distributions	(643,214)	(622,271)
Total shareholders’ equity	3,327,208	3,319,583
Total liabilities and shareholders’ equity	5,324,243	5,761,639
Series D
Preferred shares of beneficial interest, $0.01 par value: 50,000,000 shares authorized;
Series D preferred shares; 6 1/2% cumulative convertible; 4,915,196 and 4,915,497 shares issued and outstanding, respectively, aggregate liquidation preference of $122,880 and $122,887, respectively	119,263	119,266
Series E
Preferred shares of beneficial interest, $0.01 par value: 50,000,000 shares authorized;
Series E preferred shares; 7 1/4% cumulative redeemable on or after May 15, 2016; 11,000,000 shares issued and outstanding, aggregate liquidation preference $275,000	$ 265,391	$ 265,391

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Rents receivable, allowance for doubtful accounts	$ 9,281	$ 6,565
Common shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares of beneficial interest, shares authorized (in shares)	350,000,000	350,000,000
Common shares of beneficial interest, shares issued (in shares)	126,349,914	129,607,279
Common shares of beneficial interest, shares outstanding (in shares)	126,349,914	129,607,279
Series D
Preferred shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares of beneficial interest, shares authorized (in shares)	50,000,000	50,000,000
Preferred shares, dividend yield	6.50%	6.50%
Preferred shares of beneficial interest, shares issued (in shares)	4,915,196	4,915,497
Preferred shares, of beneficial interest, shares outstanding (in shares)	4,915,196	4,915,497
Preferred shares, aggregate liquidation preference	$ 122,880	$ 122,887
Series E
Preferred shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred shares of beneficial interest, shares authorized (in shares)	50,000,000	50,000,000
Preferred shares, dividend yield	7.25%	7.25%
Preferred shares of beneficial interest, shares issued (in shares)	11,000,000	11,000,000
Preferred shares, of beneficial interest, shares outstanding (in shares)	11,000,000	11,000,000
Preferred shares, aggregate liquidation preference	$ 275,000	$ 275,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenues:
Rental income	$ 125,459	$ 174,216	$ 457,128	$ 518,663
Tenant reimbursements and other income	33,749	42,379	118,829	130,386
Total revenues	159,208	216,595	575,957	649,049
Expenses:
Operating expenses	73,571	99,392	261,128	293,824
Depreciation and amortization	40,522	57,213	156,858	168,693
General and administrative	16,249	47,450	43,718	96,395
Loss on asset impairment	0	0	17,162	17,922
Acquisition related costs	0	0	0	5
Total expenses	130,342	204,055	478,866	576,839
Operating income	28,866	12,540	97,091	72,210
Interest and other income	637	406	4,813	1,071
Interest expense (including net amortization of debt discounts, premiums and deferred financing fees of $171, $(91), $23 and $(700), respectively)	(25,111)	(35,245)	(82,926)	(111,079)
(Loss) gain on early extinguishment of debt	(3,887)	6,699	6,111	6,699
Gain on sale of equity investment	0	171,754	0	171,721
Gain on issuance of shares by an equity investee	0	0	0	17,020
Foreign currency exchange loss	(9,809)	0	(8,953)	0
Gain on sale of properties	39,793	0	42,953	0
Income from continuing operations before income taxes and equity in earnings of investees	30,489	156,154	59,089	157,642
Income tax expense	(23)	(703)	(2,377)	(2,166)
Equity in earnings of investees	0	1,072	0	24,460
Income from continuing operations	30,466	156,523	56,712	179,936
Discontinued operations:
Income from discontinued operations	0	95	0	8,220
Gain (loss) on asset impairment from discontinued operations	0	122	0	(2,238)
Loss on early extinguishment of debt from discontinued operations	0	0	0	(3,345)
Net income	30,466	156,740	56,712	182,573
Preferred distributions	(6,981)	(6,981)	(20,943)	(25,114)
Excess fair value of consideration over carrying value of preferred shares	0	0	0	(16,205)
Net income attributable to Equity Commonwealth common shareholders	23,485	149,759	35,769	141,254
Amounts attributable to Equity Commonwealth common shareholders:
Income from continuing operations	23,485	149,542	35,769	138,617
Income from discontinued operations	0	95	0	8,220
Gain (loss) on asset impairment from discontinued operations	0	122	0	(2,238)
Loss on early extinguishment of debt from discontinued operations	0	0	0	(3,345)
Net income attributable to Equity Commonwealth common shareholders	$ 23,485	$ 149,759	$ 35,769	$ 141,254
Weighted average common shares outstanding — basic (in shares)	128,739	128,880	129,386	123,736
Weighted average common shares outstanding — diluted (in shares)	129,878	131,243	130,093	123,736
Basic earnings per common share attributable to Equity Commonwealth common shareholders:
Income from continuing operations (in dollars per share)	$ 0.18	$ 1.16	$ 0.28	$ 1.12
Income from discontinued operations (in dollars per share)	0	0	0	0.02
Net income (in dollars per share)	0.18	1.16	0.28	1.14
Diluted earnings per common share attributable to Equity Commonwealth common shareholders:
Income from continuing operations (in dollars per share)	0.18	1.16	0.27	1.12
Income from discontinued operations (in dollars per share)	0	0	0	0.02
Net income (in dollars per share)	0.18	1.16	0.27	1.14
Distributions declared per common share (in dollars per share)	$ 0	$ 0	$ 0	$ 0.25

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statement [Abstract]
Amortization of debt discounts, premiums and deferred financing fees	$ 0	$ (91)	$ 0	$ (700)

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 30,466	$ 156,740	$ 56,712	$ 182,573
Other comprehensive income, net of tax:
Unrealized gain (loss) on derivative instruments and other assets	821	1,805	(843)	3,432
Foreign currency translation adjustments	0	(20,392)	48,917	(4,844)
Equity in unrealized income (loss) of an investee	0	27	0	(22)
Total comprehensive income	$ 31,287	$ 138,180	$ 104,786	$ 181,139

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 56,712	$ 182,573
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	117,239	122,571
Net amortization of debt discounts, premiums and deferred financing fees	23	(703)
Straight line rental income	(3,512)	(10,398)
Amortization of acquired real estate leases	28,386	39,431
Other amortization	17,224	15,181
Share-based compensation	11,765	3,142
Loss on asset impairment	17,162	20,160
Gain on early extinguishment of debt	(6,111)	(3,354)
Equity in earnings of investees	0	(24,460)
Loss on sale of equity investments	0	(171,721)
Gain on issuance of shares by an equity investee	0	(17,020)
Distributions of earnings from investees	0	20,680
Foreign currency exchange loss	8,953	0
Net gain on sale of properties	(42,953)	0
Other non-cash expenses	0	2,402
Change in assets and liabilities:
Restricted cash	(6,275)	5,634
Rents receivable and other assets	(46,607)	(28,586)
Accounts payable and accrued expenses	(5,769)	19,826
Rent collected in advance	(6,112)	(5,399)
Security deposits	1,298	37
Due to related persons	0	(9,277)
Cash provided by operating activities	141,423	160,719
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate improvements	(43,396)	(81,935)
Principal payments received from direct financing lease	5,717	5,451
Proceeds from sale of properties, net	1,425,590	185,299
Proceeds from sale of securities	27,068	0
Proceeds from sale of equity investments, net	0	710,492
Increase in restricted cash	(3,238)	(4,796)
Cash provided by investing activities	1,411,741	814,511
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase and retirement of common shares	(87,983)	0
Payments on borrowings	(142,868)	(551,174)
Deferred financing fees	(7,143)	0
Distributions to common shareholders	0	(29,597)
Distributions to preferred shareholders	(20,943)	(25,114)
Cash used in financing activities	(258,937)	(605,885)
Effect of exchange rate changes on cash	(9,581)	(98)
Increase in cash and cash equivalents	1,284,646	369,247
Cash and cash equivalents at beginning of period	364,516	217,032
Cash and cash equivalents at end of period	1,649,162	586,279
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	93,598	118,948
Taxes paid	5,853	2,732
NON-CASH INVESTING ACTIVITIES:
(Decrease) increase in capital expenditures recorded as liabilities	$ (9,753)	$ 15,757

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of EQC have been prepared without audit. Certain information and footnote disclosures required by U.S. generally accepted accounting principles, or GAAP, for complete financial statements have been condensed or omitted. We believe the disclosures made are adequate to make the information presented not misleading. However, the accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes contained in our Annual Report on Form 10-K (Annual Report) for the year ended December 31, 2014. Capitalized terms used, but not defined in this Quarterly Report, have the same meanings as in our Annual Report. In the opinion of our management, all adjustments, which include only normal recurring adjustments considered necessary for a fair presentation, have been included. All intercompany transactions and balances with or among our subsidiaries have been eliminated. Operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. Reclassifications have been made to the prior years’ financial statements to conform to the current year’s presentation. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect reported amounts. Actual results could differ from those estimates. Significant estimates in the condensed consolidated financial statements include the allowance for doubtful accounts, purchase price allocations, useful lives of fixed assets and impairment of real estate and intangible assets. Share amounts are presented in whole numbers, except where noted.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2015
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In April 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, or ASU 2014-08. ASU 2014-08 changes the criteria for reporting a discontinued operation. Under the new pronouncement, a disposal of a part of an organization that has a major effect on its operations and financial results is a discontinued operation. We adopted ASU 2014-08 on January 1, 2015, and determined that our 2015 dispositions and properties held for sale as of September 30, 2015 do not individually represent a strategic shift, as defined by the standard, that has or will have a major effect on our operations and financial results. As a result, the 2015 dispositions have not been presented as discontinued operations in the 2015 statements of operations. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which provides guidance for revenue recognition. This update is effective for interim and annual reporting periods beginning after December 15, 2017. We are currently in the process of evaluating the impact, if any, the adoption of this ASU will have on our condensed consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs. This standard amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of as a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015, but early adoption is permitted. We do not expect that the adoption of this standard will have a material impact on our condensed consolidated financial statements.

Board of Trustees

Board of Trustees	9 Months Ended
	Sep. 30, 2015
Board of Trustees
Board of Trustees	Board of Trustees On March 18, 2014, Related Fund Management, LLC (Related) and Corvex Management LP (Corvex) together, (Related/Corvex), delivered written consents which they represented were from a sufficient number of holders of our outstanding common shares to remove all of our then Trustees (former Trustees) and any other person or persons elected or appointed to our Board of Trustees prior to the effective time of the Related/Corvex removal proposal. After inspection, our then Board of Trustees determined that holders of more than two-thirds of our outstanding common shares as of the February 18, 2014 record date consented to the Related/Corvex proposal, reaching the threshold required to remove all of our then Trustees and any other person or persons appointed as a Trustee prior to the effective time of the Related/Corvex removal proposal. Accordingly, on March 25, 2014, all of our former Trustees certified their removal as Trustees of EQC. On May 23, 2014, at a special meeting of our shareholders (Special Meeting), the following seven individuals were elected to serve on our Board of Trustees: Sam Zell, who serves as the Chairman of the new Board of Trustees, James S. Corl, Edward A. Glickman, David A. Helfand, Peter Linneman, James L. Lozier, Jr. and Kenneth Shea. Each of the foregoing individuals was nominated to serve on the new Board of Trustees by Related/Corvex. On July 31, 2014, our shareholders re-elected the seven individuals listed above and elected Martin L. Edelman, Mary Jane Robertson, Gerald A. Spector and James A. Star to serve on our Board of Trustees, bringing our total number of Trustees to eleven (new Board of Trustees). At the 2015 annual meeting of shareholders held on June 16, 2015, our shareholders re-elected each of our eleven Trustees to serve on our Board of Trustees for the 2015-2016 term.

Real Estate Properties

Real Estate Properties	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
Real Estate Properties	Real Estate Properties During the nine months ended September 30, 2015 and 2014 , we made improvements, excluding tenant-funded improvements, to our properties totaling $46.7 million and $ 65.9 million , respectively. Properties Held For Sale: We classify all properties that meet the criteria outlined in the Property, Plant and Equipment Topic of the FASB Accounting Standards Codification (Codification) as held for sale on our condensed consolidated balance sheets. As of December 31, 2014, we had no properties classified as held for sale. As of September 30, 2015 , we classified the following properties as held for sale (dollars in thousands): Asset Date Sold Segment Number of Number of Square Footage Gross Sales Price Properties One South Church Avenue October 2015 CBD 1 1 240,811 $ 32,000 775 Ridge Lake Boulevard October 2015 CBD 1 1 120,678 16,300 One Park Square October 2015 CBD 1 6 259,737 34,300 Portfolio of Properties 9040 Roswell Road October 2015 Suburban 1 1 178,941 The Exchange October 2015 Suburban 1 2 187,632 3920 Arkwright Road October 2015 Suburban 1 1 196,156 1775 West Oak Commons Court October 2015 Suburban 1 1 79,854 Georgia portfolio 4 5 642,583 $ 48,550 7 13 1,263,809 $ 131,150 Summarized balance sheet information for all properties classified as held for sale is as follows (in thousands): September 30, 2015 Real estate properties $ 108,023 Other assets, net 4,127 Properties held for sale $ 112,150 Accounts payable and accrued expenses $ 1,479 Security deposits 430 Liabilities related to properties held for sale $ 1,909 Property Dispositions: During the nine months ended September 30, 2015 , we disposed of the following properties (dollars in thousands): Asset Date Disposed Segment Number of Number of Square Footage Gross Sales Price Gain (Loss) on Sale Properties 11350 North Meridian Street January 2015 Suburban 1 1 72,264 $ 4,200 $ 766 333 Laurel Oak Drive (1) March 2015 Suburban — 1 27,164 2,450 251 1921 E. Alton Avenue March 2015 Suburban 1 1 67,846 14,533 4,850 46 Inverness Center Parkway April 2015 Suburban — — — 2,000 1,857 225 Water Street (2) May 2015 CBD 1 1 318,997 — — Sorrento Valley Business Park June 2015 Suburban 1 4 105,003 23,500 11,896 Illinois Center August 2015 CBD 1 2 2,090,162 376,000 26,929 16th and Race Street August 2015 CBD 1 1 608,625 43,000 7,922 185 Asylum Street September 2015 CBD 1 1 868,395 113,250 17,619 Portfolio of properties 7450 Campus Drive May 2015 Suburban 1 1 77,411 129 Worthington Ridge Road May 2015 Suburban 1 1 227,500 599 Research Parkway May 2015 Suburban 1 1 48,249 181 Marsh Hill Road May 2015 Suburban 1 1 162,036 101 Barnes Road May 2015 Suburban 1 1 45,755 15 Sterling Drive May 2015 Suburban 1 1 173,015 35 Thorpe Avenue May 2015 Suburban 1 1 79,862 50 Barnes Industrial Road North May 2015 Suburban 1 1 154,255 5-9 Barnes Industrial Road May 2015 Suburban 1 1 38,006 860 North Main Street May 2015 Suburban 1 1 31,165 One Barnes Industrial Road South May 2015 Suburban 1 1 30,170 Village Lane May 2015 Suburban 1 2 58,185 100 Northfield Drive May 2015 Suburban 1 1 116,986 905 Meridian Lake Drive May 2015 Suburban 1 1 74,652 1717 Deerfield Road May 2015 Suburban 1 1 141,186 1955 West Field Court May 2015 Suburban 1 1 59,130 5015 S. Water Circle May 2015 Suburban 1 1 113,524 Adams Place May 2015 Suburban 1 2 230,259 Cabot Business Park May 2015 Suburban 1 2 252,755 2300 Crown Colony Drive May 2015 Suburban 1 1 45,974 Myles Standish Industrial Park May 2015 Suburban 1 2 74,800 340 Thompson Road May 2015 Suburban 1 1 25,000 100 South Charles Street May 2015 CBD 1 1 159,616 6710 Oxon Hill May 2015 Suburban 1 1 118,336 8800 Queen Avenue South May 2015 Suburban 1 1 280,822 9800 Sherlard Parkway May 2015 Suburban 1 1 46,765 Rosedale Corporate Plaza May 2015 Suburban 1 3 149,116 1000 Shelard Parkway May 2015 Suburban 1 1 62,499 525 Park Street May 2015 CBD 1 1 75,636 Asset Date Disposed Segment Number of Number of Square Footage Gross Sales Price Gain (Loss) on Sale 1900 Meyer Drury Drive May 2015 Suburban 1 1 65,225 131-165 West Ninth Street May 2015 Suburban 1 1 75,517 7-9 Vreeland Road May 2015 Suburban 1 1 155,891 5 Paragon Drive May 2015 Suburban 1 1 119,089 1000 Vorhees Drive and 400 Laurel Oak Drive(1) May 2015 Suburban 1 2 125,415 1601 Veterans Highway May 2015 Suburban 1 1 63,608 Two Corporate Center Drive May 2015 Suburban 1 1 291,230 11311 Cornell Park Drive May 2015 Suburban 1 1 93,413 5300 Kings Island Drive May 2015 Suburban 1 1 159,421 3 Crown Point Court May 2015 Suburban 1 1 73,987 515 Pennsylvania Avenue May 2015 Suburban 1 1 82,000 443 Gulph Road May 2015 Suburban 1 1 21,000 4350 Northern Pike May 2015 Suburban 1 1 503,885 Thunderbolt Place May 2015 Suburban 1 2 100,505 6160 Kempsville Circle May 2015 Suburban 1 1 129,565 448 Viking Drive May 2015 Suburban 1 1 75,374 Portfolio of small office and industrial assets 45 53 5,287,790 $ 376,000 $ (8,075 ) 2501 20th Place South June 2015 CBD 1 1 125,722 420 20th Street North June 2015 CBD 1 1 514,893 Inverness Center June 2015 Suburban 1 4 475,882 701 Poydras Street June 2015 CBD 1 1 1,256,971 300 North Greene Street June 2015 CBD 1 1 324,305 1320 Main Street June 2015 CBD 1 1 334,075 AL, LA, NC, SC office portfolio 6 9 3,031,848 $ 417,450 $ 41,596 12655 Olive Boulevard June 2015 Suburban 1 1 98,588 1285 Fern Ridge Parkway June 2015 Suburban 1 1 66,510 St. Louis portfolio 2 2 165,098 $ 14,300 $ (2,349 ) 310-314 Invermay Road (3) April 2015 Suburban 1 1 47,480 253-293 George Town Road (3) April 2015 Suburban 1 1 143,914 7 Modal Crescent June 2015 Suburban 1 1 164,160 71-93 Whiteside Road June 2015 Suburban 1 1 303,488 9-13 Titanium Court June 2015 Suburban 1 1 69,664 16 Rodborough Road June 2015 Suburban 1 1 90,525 22 Rodborough Road June 2015 Suburban 1 1 43,427 127-161 Cherry Lane June 2015 Suburban 1 1 278,570 310-320 Pitt Street June 2015 CBD 1 1 313,865 44-46 Mandarin Street June 2015 Suburban 1 1 226,718 19 Leadership Way June 2015 Suburban 1 1 76,714 Australia portfolio(4) 11 11 1,758,525 $ 232,955 $ (47,851 ) Asset Date Disposed Segment Number of Number of Square Footage Gross Sales Price Gain (Loss) on Sale Widewaters Parkway August 2015 Suburban 1 8 514,241 5062 Brittonfield Parkway August 2015 Suburban 1 1 40,162 Woodcliff Drive August 2015 Suburban 1 6 516,760 Interstate Place August 2015 Suburban 1 2 61,399 1000 Pittsford - Victor Road August 2015 Suburban 1 1 73,358 1200 Pittsford - Victor Road August 2015 Suburban 1 1 18,900 Corporate Crossing August 2015 Suburban 1 5 216,126 Canal View Boulevard August 2015 Suburban 1 3 118,375 14 Classic Street August 2015 Suburban 1 1 37,084 110 W Fayette Street August 2015 CBD 1 1 304,906 251 Salina Meadows Parkway August 2015 Suburban 1 1 65,617 Upstate New York portfolio 11 30 1,966,928 $ 104,625 $ (12,458 ) 82 117 16,368,645 $ 1,724,263 $ 42,953 (1) This property contains three buildings. We sold one building in March 2015 and two buildings in May 2015. (2) Title to this property was transferred to the lender pursuant to a consensual foreclosure in full satisfaction of the mortgage debt with a principal balance of $40.1 million , resulting in a gain on early extinguishment of debt of $17.3 million for the nine months ended September 30, 2015. See Note 8 for additional information. (3) These properties were sold in a separate transaction to a different buyer than other Australian properties. (4) The loss on sale includes a $63.2 million cumulative foreign currency translation adjustment reclassified from cumulative other comprehensive loss due to the disposition of the Australian portfolio. On June 27, 2014, we sold one CBD property ( two buildings) and 13 suburban properties ( 41 buildings) with a combined 2,784,098 square feet for an aggregate sales price of $215.9 million , excluding mortgage debt repayments and closing costs. In conjunction with this transaction, we recognized a loss on asset impairment of $2.4 million and a loss on early extinguishment of debt of $3.3 million . Results of operations for properties sold prior to December 31, 2014, are included in discontinued operations in our condensed consolidated statements of operations. Summarized income statement information for properties included in discontinued operations is as follows (in thousands): Three Months Ended Nine Months Ended September 30, 2014 Rental income $ (16 ) $ 14,220 Tenant reimbursements and other income 407 1,730 Total revenues 391 15,950 Operating expenses 261 7,115 General and administrative 6 9 Total expenses 267 7,124 Operating income 124 8,826 Interest and other income 2 2 Interest expense (31 ) (608 ) Income from discontinued operations $ 95 $ 8,220

Investment in Direct Financing

Investment in Direct Financing Lease	9 Months Ended
	Sep. 30, 2015
Capital Leases, Net Investment in Direct Financing Leases [Abstract]
Investment in Direct Financing Lease	Investment in Direct Financing Lease We have an investment in a direct financing lease that relates to a lease with a term that exceeds 75% of the useful life of an office tower located within a mixed use property in Phoenix, AZ. We recognize income using the effective interest method to produce a level yield on funds not yet recovered. The carrying amount of our net investment of $6.7 million and $12.5 million as of September 30, 2015 and December 31, 2014, respectively, is included in other assets in our condensed consolidated balance sheets. We monitor the payment history and credit profile of the tenant and have determined that no allowance for losses related to our direct financing lease was necessary at September 30, 2015 and December 31, 2014 . Our direct financing lease has an expiration date in 2045.

Equity Investments

Equity Investments	9 Months Ended
	Sep. 30, 2015
Equity Method Investments and Joint Ventures [Abstract]
Equity Investments	Equity Investments Investment in SIR SIR is a REIT that is primarily focused on owning and investing in net leased, single tenant properties. SIR was an unconsolidated equity method investment from July 2, 2013 until July 9, 2014 . On July 9, 2014 , we sold our entire stake of 22,000,000 common shares of SIR. As a result of this sale, we no longer hold any interest in SIR. For the three and nine months ended September 30, 2014 , we recorded equity in earnings of $1.1 million and $24.5 million , respectively, related to our investment in SIR on our condensed consolidated statement of operations. During the nine months ended September 30, 2014 , we received cash distributions from SIR totaling $20.7 million . The following unaudited summarized income statement information of SIR for the period from July 1, 2014 through July 9, 2014 and for the period from January 1, 2014 through July 9, 2014 is as follows (in thousands, except per share data): For the Period from July 1, 2014 through July 9, 2014 For the Period from January 1, 2014 through July 9, 2014 Rental income $ 4,698 98,226 Tenant reimbursements and other income 923 16,980 Total revenues 5,621 115,206 Operating expenses 1,018 20,982 Depreciation and amortization 1,043 20,832 Acquisition related costs — 374 General and administrative 357 7,731 Total expenses 2,418 49,919 Operating income 3,203 65,287 Interest expense (295 ) (7,287 ) Gain on early extinguishment of debt — 243 Income before income tax expense and equity in earnings of an investee 2,908 58,243 Income tax expense — (90 ) Equity in earnings of an investee 11 32 Net income $ 2,919 $ 58,185 Weighted average common shares outstanding 59,889 52,394 Net income per common share $ 0.05 $ 1.11 Investment in AIC As of May 9, 2014, we had a net investment of $5.8 million in AIC, an insurance company that was owned in equal proportion by us, our former manager Reit Management & Research LLC (RMR), SIR and five other companies to which RMR provides management services. On May 9, 2014, as a result of the removal of the former Trustees and in accordance with the terms of the shareholder agreement between us and the other AIC shareholders, the other AIC shareholders exercised their right to purchase all of the 20,000 shares of AIC we then owned. We received $5.8 million in aggregate proceeds from this sale. We no longer own any interest in AIC. For the period from January 1, 2014 through May 9, 2014, we recorded equity in loss of $0.1 million related to our investment in AIC on our condensed consolidated statement of operations. Our participation in the AIC property insurance program expired in June 2014. See Note 17 for additional information about our investment in AIC.

Real Estate Mortgages Receivabl

Real Estate Mortgages Receivable	9 Months Ended
	Sep. 30, 2015
Real Estate Mortgages Receivable
Real Estate Mortgages Receivable	Real Estate Mortgages Receivable As of September 30, 2015 and December 31, 2014 , we had total real estate mortgages receivable with an aggregate carrying value of $8.1 million included in other assets in our condensed consolidated balance sheets. We provided mortgage financing totaling $7.7 million at 6.0% per annum in connection with our sale of three suburban office and industrial properties ( 18 buildings) in January 2013 in Dearborn, MI; this real estate mortgage requires monthly interest payments and matures on January 24, 2023 . We also provided mortgage financing totaling $0.4 million at 6.0% per annum in connection with our sale of a suburban office property in Salina, NY in April 2012. This real estate mortgage requires monthly interest payments and matures on April 30, 2019 . We monitor the payment history of the borrowers and have determined that no allowance for losses related to these real estate mortgages receivable were necessary at September 30, 2015 , and December 31, 2014 .

Indebtedness

Indebtedness	9 Months Ended
	Sep. 30, 2015
Debt Disclosure [Abstract]
Indebtedness	Indebtedness Unsecured Revolving Credit Facility and Term Loan: Prior to January 29, 2015, we had a $750.0 million unsecured revolving credit facility. The unsecured revolving credit facility was set to mature on October 19, 2015, and had an interest rate of LIBOR plus a spread, which was 150 basis points as of December 31, 2014. We paid a facility fee of 35 basis points per annum on the total amount of lending commitments under our revolving credit facility. Prior to January 29, 2015, we also had a $400.0 million unsecured term loan that was set to mature on December 15, 2016. Our term loan had an interest rate of LIBOR plus a spread, which was 185 basis points as of December 31, 2014. On January 29, 2015, we entered into a new credit agreement, pursuant to which the lenders agreed to provide (i) a $750.0 million unsecured revolving credit facility, (ii) a $200.0 million 5 -year term loan facility and (iii) a $200.0 million 7 -year term loan facility. The new agreement replaced our prior credit agreement, dated as of August 9, 2010, and our prior term loan agreement, dated as of December 16, 2010. In connection with the new agreement, we recognized a loss on early extinguishment of debt of $0.4 million from the write-off of unamortized deferred financing fees for the nine months ended September 30, 2015 . The revolving credit facility has a scheduled maturity date of January 28, 2019, which maturity date may be extended for up to two additional periods of six months at our option subject to satisfaction of certain conditions and the payment of an extension fee of 0.075% of the aggregate amount available under the revolving credit facility. The 5-year term loan and the 7-year term loan have scheduled maturity dates of January 28, 2020 and January 28, 2022, respectively. We used the proceeds of borrowings under the credit agreement to repay all amounts outstanding and due under the previous term loan agreement. The credit agreement permits us to utilize up to $100.0 million of the revolving credit facility for the issuance of letters of credit. Amounts outstanding under the credit agreement generally may be prepaid at any time without premium or penalty, subject to certain exceptions. We have the right to request increases in the aggregate maximum amount of borrowings available under the revolving credit facility and term loans up to an additional $1.15 billion , subject to certain conditions. Borrowings under the 5-year term loan and 7-year term loan will, subject to certain exceptions, bear interest at a LIBOR rate plus a margin of 90 to 180 basis points for the 5-year term loan and 140 to 235 basis points for the 7-year term loan, in each case depending on our credit rating. Borrowings under the revolving credit facility will, subject to certain exceptions, bear interest at a rate equal to, at our option, either a LIBOR rate or a base rate plus a margin of 87.5 to 155 basis points for LIBOR rate advances and 0 to 55 basis points for base rate advances, in each case depending on our credit rating. In addition, we are required to pay a facility fee of 12.5 to 30 basis points, depending on our credit rating, on the borrowings available under the revolving credit facility, whether or not utilized. Borrowings under our revolving credit facility currently bear interest at LIBOR plus a spread, which was 125 basis points as of September 30, 2015 . As of September 30, 2015 , the interest rate payable on borrowings under our revolving credit facility was 1.44% . As of September 30, 2015 , we had no balance outstanding and $750.0 million available under our revolving credit facility. Our term loans currently bear interest at a rate of LIBOR plus a spread, which was 140 and 180 basis points for the 5-year and 7-year term loan, respectively, as of September 30, 2015 . As of September 30, 2015 , the interest rates for the amounts outstanding under our 5-year term loan and 7-year term loan were 1.59% and 1.99% , respectively. As of September 30, 2015 , we had $200.0 million outstanding under each of our 5-year and 7-year term loans. Debt Covenants: Our public debt indenture and related supplements, our revolving credit facility agreement and our term loan agreement contain a number of financial and other covenants, including covenants that restrict our ability to incur indebtedness or to make distributions under certain circumstances and require us to maintain financial ratios and a minimum net worth. At September 30, 2015 , we believe we were in compliance with all of our respective covenants under our public debt indenture and related supplements, our revolving credit facility and our term loan agreements. Senior Unsecured Notes: On May 1, 2015, we redeemed at par $138.8 million of our 5.75% senior unsecured notes due 2015 and recognized a loss on early extinguishment of debt of $0.1 million from the write-off of an unamortized discount and unamortized deferred financing fees. Mortgage Notes Payable: At September 30, 2015 , six of our properties ( 10 buildings) with an aggregate net book value of $452.4 million had secured mortgage notes totaling $367.7 million (including net premiums and discounts) maturing from 2016 through 2026. During the quarter ended June 30, 2014, we made the decision to cease making loan servicing payments on 225 Water Street in Jacksonville, Florida. The first payment we determined not to make for this property was due on June 11, 2014. The property was secured by a non-recourse mortgage loan. On October 10, 2014, we were notified by the lender that our decision to cease making loan servicing payments created an event of default effective July 11, 2014, and the lender exercised its option to accelerate the maturity of the unpaid balance of the loan. Beginning July 11, 2014, we accrued interest on this loan at 10.03% , to include the 4.0% of default interest. The lender filed a suit of foreclosure for this property and we cooperated with the lender to allow for a consensual foreclosure process. On May 22, 2015, title to 225 Water Street was transferred to the lender pursuant to the consensual foreclosure in full satisfaction of the mortgage debt, with a principal balance of $40.1 million . The transaction resulted in a gain on early extinguishment of debt of $17.3 million for the excess of the debt principal balance over the net book value of the property for the nine months ended September 30, 2015 . In accordance with the agreement to sell 1320 Main Street, we were required to deliver the property unencumbered. On June 3, 2015, prior to the sale, we defeased the $38.7 million outstanding balance of the mortgage loan secured by 1320 Main Street. The defeasance costs and write off of the unamortized deferred financing costs, net of the write off of the unamortized premium, resulted in a net loss on early extinguishment of debt of $6.2 million for the nine months ended September 30, 2015 . In accordance with the agreement to sell 2501 20th Place South, we were required to deliver the property unencumbered. On June 5, 2015, we prepaid $10.0 million of 7.36% mortgage debt at 2501 20th Place South and recognized a loss on early extinguishment of debt totaling $0.6 million for the nine months ended September 30, 2015 , which consisted of a prepayment premium and the write off of unamortized deferred financing fees, net of the write off of an unamortized premium. In accordance with the agreement to sell Illinois Center, we were required to deliver the property unencumbered. On August 3, 2015, prior to the sale, we defeased the outstanding $141.4 million balance of the mortgage loan secured by 111 East Wacker Drive, one of the buildings included in Illinois Center. The defeasance costs and write off of the unamortized deferred financing costs, net of the write off of the unamortized premium, resulted in a net loss on early extinguishment of debt of $3.9 million for the three and nine months ended September 30, 2015 .

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2015
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Common Share Issuances: During the nine months ended September 30, 2015 , we issued 144 common shares to holders of 301 of our series D cumulative convertible preferred shares (series D preferred shares) who elected to convert their series D preferred shares into our common shares. During 2014, we issued 10,412,499 common shares to holders of 10,264,503 of our series D preferred shares who converted their series D preferred shares into our common shares. See Note 13 for information regarding equity issuances related to share-based compensation. Common Share Repurchases: On August 24, 2015, our Board of Trustees approved a common share repurchase plan, which authorizes the repurchase of up to $100.0 million of our outstanding common shares over the twelve month period following the date of authorization. On September 14, 2015, our Board of Trustees authorized the repurchase of up to an additional $100.0 million of our outstanding common shares over the twelve month period following the date of authorization. During the three and nine months ended September 30, 2015, we purchased and retired 3,410,300 of our common shares at a weighted average price of $25.76 per share. Preferred Share Distributions: In 2015, our Board of Trustees declared distributions on our series D preferred shares and series E cumulative redeemable preferred shares to date as follows: Declaration Date Record Date Payment Date Series D Dividend Per Share Series E Dividend Per Share January 16, 2015 February 2, 2015 February 17, 2015 $ 0.40625 $ 0.453125 April 8, 2015 May 1, 2015 May 15, 2015 $ 0.40625 $ 0.453125 July 9, 2015 July 31, 2015 August 17, 2015 $ 0.40625 $ 0.453125 October 9, 2015 November 2, 2015 November 16, 2015 $ 0.40625 $ 0.453125 Series D Preferred Shares: The removal of our former Trustees on March 25, 2014, triggered a Fundamental Change Conversion Right of the series D preferred shares, as defined in our Articles Supplementary dated October 10, 2006, setting forth the terms of the series D preferred shares. Pursuant to such right, the holders of series D preferred shares had the option to elect to convert all or any portion of their series D preferred shares at any time from April 9, 2014 until the close of business on May 14, 2014 into a number of common shares per $25.00 liquidation preference of the series D preferred shares equal to the sum of such $25.00 liquidation preference plus accrued and unpaid dividends to, but not including, May 14, 2014, divided by 98% of the average of the closing sale prices of the common shares for the five consecutive trading days ending on May 9, 2014, or the Fundamental Change Conversion Rate. Holders of 10,263,003 series D preferred shares elected to exercise their Fundamental Change Conversion Right and converted their series D preferred shares into 10,411,779 of our common shares. As a result of this transaction, we recorded a preferred distribution of $16.2 million , for the excess of the market value of the common shares issued above the carrying value of the series D preferred shares redeemed. As of September 30, 2015 , we had 4,915,196 outstanding series D preferred shares that were convertible into 2,363,103 of our common shares.

Cumulative Other Comprehensive

Cumulative Other Comprehensive Loss	9 Months Ended
	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Cumulative Other Comprehensive Loss	Cumulative Other Comprehensive Loss The following tables present the amounts recognized in cumulative other comprehensive loss by component for the three and nine months ended September 30, 2015 (in thousands): Three Months Ended September 30, 2015 Unrealized Loss on Derivative Instruments and Other Assets Foreign Currency Translation Adjustments Total Balances as of July 1, 2015 $ (5,963 ) $ — $ (5,963 ) Other comprehensive loss before reclassifications (418 ) — (418 ) Amounts reclassified from cumulative other comprehensive loss to net income 1,239 — 1,239 Net current period other comprehensive income 821 — 821 Balances as of September 30, 2015 $ (5,142 ) $ — $ (5,142 ) Nine Months Ended September 30, 2015 Unrealized Loss on Derivative Instruments and Other Assets Foreign Currency Translation Adjustments Total Balances as of January 1, 2015 $ (4,299 ) $ (48,917 ) $ (53,216 ) Other comprehensive loss before reclassifications (1,461 ) (14,290 ) (15,751 ) Amounts reclassified from cumulative other comprehensive loss to net income 618 63,207 63,825 Net current period other comprehensive (loss) income (843 ) 48,917 48,074 Balances as of September 30, 2015 $ (5,142 ) $ — $ (5,142 ) The following tables present reclassifications out of cumulative other comprehensive loss for the three and nine months ended September 30, 2015 (in thousands): Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income Details about Cumulative Other Comprehensive Loss Components Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 Affected Line Items in the Statement of Operations Interest rate swap contracts $ 1,239 $ 3,698 Interest expense Foreign currency translation adjustment activity — 63,207 Gain on sale of properties Realized gain on available for sale securities — (3,080 ) Interest and other income $ 1,239 $ 63,825

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We have elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended, and are generally not subject to federal and state income taxes provided we distribute a sufficient amount of our taxable income to our shareholders and meet other requirements for qualifying as a REIT. Federal income tax expense for the nine months ended September 30, 2015 relates to taxes incurred as a result of a taxable built-in gain triggered by the sale of a property that was previously owned by a C corporation. We are also subject to certain state, local and Australian taxes without regard to our REIT status. Our provision for income taxes consists of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Current: State $ 90 $ 39 $ 270 $ 300 Federal — — 525 — Foreign (67 ) 664 2,337 1,866 23 703 3,132 2,166 Deferred: Foreign — — (755 ) — — — (755 ) — Income tax expense $ 23 $ 703 $ 2,377 $ 2,166

Derivative Instruments

Derivative Instruments	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments Risk Management Objective of Using Derivatives We are exposed to certain risks relating to our ongoing business operations, including the effect of changes in foreign currency exchange rates and interest rates. The only risk we currently manage by using derivative instruments is a part of our interest rate risk. We may use derivative financial instruments, including interest rate swaps, caps, options, floors and other interest rate derivative contracts, to hedge all or a portion of the interest rate risk associated with our borrowings. The principal objective of such arrangements is to minimize the risks and/or costs associated with our operating and financial structure as well as to hedge specific anticipated transactions. We do not intend to utilize derivatives for speculative or other purposes other than interest rate risk management. The use of derivative financial instruments carries certain risks, including the risk that the counterparties to these contractual arrangements are not able to perform under the agreements. To mitigate this risk, we only enter into derivative financial instruments with counterparties with high credit ratings and with major financial institutions with which we and our affiliates may also have other financial relationships. We do not anticipate that any of the counterparties will fail to meet their obligations. Cash Flow Hedges of Interest Rate Risk Our objectives in using interest rate derivatives are to add stability to interest expense and to manage our exposure to interest rate movements. To accomplish this objective, we periodically use interest rate swaps, caps, or other similar instruments as part of our interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for us making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in cumulative other comprehensive loss and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. During 2015, such derivatives were used to hedge the variable cash flows associated with variable-rate debt. The ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. Amounts reported in cumulative other comprehensive loss related to derivatives will be reclassified to interest expense as interest payments are made on our variable-rate debt. During the next twelve months, we estimate that an additional $4.5 million will be reclassified from cumulative other comprehensive loss as an increase to interest expense. We have interest rate swap agreements to manage our interest rate risk exposure on $170.1 million of mortgage debt due 2019, which require interest at a spread over LIBOR . The interest rate swap agreements utilized by us qualify as cash flow hedges and effectively modify our exposure to interest rate risk by converting our floating interest rate debt to a fixed interest rate basis for this loan through December 1, 2016, thus reducing the impact of interest rate changes on future interest expense. As of September 30, 2015 , we had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk: Interest Rate Derivative Number of Instruments Notional Amount (in thousands) Interest rate swap 2 $170,097 The table below presents the fair value of our derivative financial instruments as well as their classification on the condensed consolidated balance sheets as of September 30, 2015 and December 31, 2014 (amounts in thousands): Fair Value as of Interest Rate Derivative Designated as Hedging Instrument Balance Sheet Location September 30, December 31, Pay-fixed swaps Accounts payable and accrued expenses $ 5,142 $ 7,462 The table below details the location in the financial statements of the gain or loss recognized on interest rate derivatives designated as cash flow hedges for the three and nine months ended September 30, 2015 and 2014 (amounts in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Balance at beginning of period $ (5,963 ) $ (10,079 ) $ (7,462 ) $ (11,706 ) Amount of (loss) gain recognized in cumulative other comprehensive loss (418 ) 537 (1,378 ) (324 ) Amount of loss reclassified from cumulative other comprehensive loss into interest expense 1,239 1,268 3,698 3,756 Unrealized gain on derivative instruments 821 1,805 2,320 3,432 Balance at end of period $ (5,142 ) $ (8,274 ) $ (5,142 ) $ (8,274 ) Credit-risk-related Contingent Features We have agreements with each of our derivative counterparties that contain a provision where if we either default or are capable of being declared in default on any of our indebtedness, then we could also be declared in default on our derivative obligations. As of September 30, 2015 , the fair value of derivatives in a net liability position including accrued interest but excluding any adjustment for nonperformance risk related to these agreements was $5.6 million . As of September 30, 2015 , we have not posted any collateral related to these agreements and were not in breach of any agreement provisions. If we had breached any of these provisions, we could have been required to settle our obligations under the agreements at their aggregate termination value of $5.6 million at September 30, 2015 .

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation Equity Commonwealth 2015 Omnibus Incentive Plan On June 16, 2015, at our 2015 annual meeting of shareholders, our shareholders approved the Equity Commonwealth 2015 Omnibus Incentive Plan (the 2015 Incentive Plan). The 2015 Incentive Plan replaced the Equity Commonwealth 2012 Equity Compensation Plan (as amended, the 2012 Plan). The Board of Trustees approved the 2015 Incentive Plan, subject to shareholder approval, on March 18, 2015 (the Effective Date). The following description of certain terms of the 2015 Incentive Plan is qualified in all respects by the terms of the 2015 Incentive Plan. Eligibility. Awards may be granted under the 2015 Incentive Plan to employees, officers and non-employee directors of the Company, its subsidiaries or its affiliates, or consultants and advisors (who are natural persons) providing services to the Company, its subsidiaries or its affiliates, or any other person whose participation in the 2015 Incentive Plan is determined by the Compensation Committee to be in the best interests of the Company. Term . The 2015 Incentive Plan terminates automatically ten years after the Effective Date, unless it is terminated earlier by the Board of Trustees. Shares Available for Issuance. Subject to adjustment as provided in the 2015 Incentive Plan, the maximum number of common shares of the Company that are available for issuance under the 2015 Incentive Plan is 3,250,000 shares. Awards. The following types of awards may be made under the 2015 Incentive Plan, subject to limitations set forth in the 2015 Incentive Plan: · Stock options; · Stock appreciation rights; · Restricted stock; · Restricted stock units; · Unrestricted stock; · Dividend equivalent rights; · Performance shares and other performance-based awards; · Limited partnership interests in any partnership entity through which the Company may conduct its business in the future; · Other equity-based awards; and · Cash bonus awards. Recipients of the Company’s restricted shares have the same voting rights as any other common shareholder. During the period of restriction, the Company’s unvested restricted shareholders are eligible to receive dividend payments on their shares at the same rate and on the same date as any other common shareholder. Recipients of the Company’s restricted stock units (RSUs) are entitled to receive dividends with respect to the common shares underlying the RSUs if and when the RSUs are earned, at which time the recipient will be entitled to receive an amount in cash equal to the aggregate amount of ordinary cash dividends that would have been paid in respect of the common shares underlying the recipient’s earned RSUs had such common shares been issued to the recipient on the first day of the performance period. Administration. The 2015 Incentive Plan will be administered by the Compensation Committee, which will determine all terms and recipients of awards under the 2015 Incentive Plan. 2012 Equity Compensation Plan In the past, the Company has granted equity-based compensation under the 2012 Plan. The 2012 Plan authorized grants of the Company’s restricted common shares and RSUs. The 2015 Incentive Plan replaced the 2012 Plan. No future grants will be made under the 2012 Plan, although the terms and conditions of the 2012 Plan will continue to govern any outstanding awards granted under the 2012 Plan. 2015 Equity Award Activity On June 16, 2015, in accordance with the Company’s compensation plan for independent Trustees, the Committee awarded each of the nine independent Trustees $0.1 million in restricted shares as part of their compensation for the 2015-2016 year of service on the Board of Trustees. These awards equated to 3,843 shares per Trustee, for a total of 34,587 shares, valued at $26.02 per share, the closing price of our common shares on the NYSE on that day. These shares vest one year after the date of the award. During the nine months ended September 30, 2015 , 8,115 restricted shares were forfeited with an average per share fair value at grant date of $26.64 , and 16,475 RSUs were forfeited with an average per share fair value at grant date of $20.50 . Equity Grants for 2014 Performance On January 28, 2015, the Committee approved a grant of 126,319 restricted common shares and 256,467 RSUs at target to the Company’s officers, certain employees and to Mr. Zell, the Chairman of our Board of Trustees, as part of their compensation for fiscal year 2014. The restricted shares are service based awards and vest over a four -year period. The restricted shares were granted on January 28, 2015 and were valued at $26.58 per share, the closing price of our common shares on the NYSE on that day. As of September 30, 2015 , the estimated future compensation expense for all unvested restricted share grants was $16.0 million . Compensation expense for the restricted share awards is being recognized on a straight-line basis over the requisite service period for each separately vesting portion of the award. The weighted average period over which the future compensation expense will be recorded for the restricted shares is approximately 3.0 years. The RSUs are market based awards with a service condition and grant recipients may earn the RSU grants based on the Company’s total shareholder return (TSR) relative to the TSR's for the constituent REITs that comprise the NAREIT Office Index for the performance period of January 28, 2015 - January 28, 2018. Following the end of the performance period on January 28, 2018, the number of earned awards will be determined. The earned awards vest in two tranches with 50% of the earned award vesting on January 28, 2018 and the remaining 50% of the earned award vesting on January 28, 2019, subject to the grant recipient’s continued employment. Recipients of the Company’s RSUs are entitled to receive dividends with respect to the common shares underlying the RSUs if and when the RSUs are earned. To the extent that an award does not vest, the dividends will be forfeited. Compensation expense for the RSU awards was determined using a Monte Carlo simulation model and is being recognized ratably from the grant date to the vesting date of each tranche. As of September 30, 2015 , the estimated future compensation expense for all unvested RSUs was $22.5 million . The weighted average period over which the future compensation expense will be recorded for the RSUs is approximately 2.7 years. The assumptions and fair values for the RSUs granted for the nine months ended September 30, 2015 are included in the following table on a per share basis. 2015 Fair value of RSUs granted $ 38.55 Expected term (years) 4 Expected volatility — Expected dividend yield 1.88 % Risk-free rate 0.81 % During the three and nine months ended September 30, 2015 , we recorded $3.7 million and $11.8 million , respectively, of compensation expense, net of forfeitures, in general and administrative expense for grants to our Board of Trustees and the Company's employees related to our Plan. At September 30, 2015 , 3,215,413 common shares remain available for issuance under the Plan. Prior Equity Grants As a result of the removal of our former Trustees on March 25, 2014, the vesting of 130,914 common shares previously issued to our former officers and certain employees of RMR pursuant to our equity compensation plans accelerated in accordance with the terms of their governing share grants. During the nine months ended September 30, 2014 , we recorded $3.4 million of general and administrative expense related to the vesting of these shares.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities The table below presents certain of our assets and liabilities measured at fair value during 2015 , categorized by the level of inputs used in the valuation of each asset and liability (dollars in thousands): Fair Value at September 30, 2015 Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description Total (Level 1) (Level 2) (Level 3) Recurring Fair Value Measurements: Effective portion of interest rate swap contracts $ (5,142 ) $ — $ (5,142 ) $ — Derivative liability (5,159 ) — — (5,159 ) Effective Portion of Interest Rate Swap Contracts The fair value of our interest rate swap contracts is determined using the net discounted cash flows of each derivative based on the market based interest rate curve (level 2 inputs) and adjusted for our credit spread and the actual and estimated credit spreads of the counterparties (level 3 inputs). Although we have determined that the majority of the inputs used to value our derivatives fall within level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize level 3 inputs, such as estimates of current credit spreads, to evaluate the likelihood of default by us and the counterparties. As of September 30, 2015 , we have assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivative positions and have determined that the credit valuation adjustments are not significant to the overall valuation of our derivatives. As a result, we have determined that our derivative valuations in their entirety are classified as level 2 inputs in the fair value hierarchy. Derivative Liability On July 31, 2014, our shareholders voted to approve the reimbursement of expenses incurred by Related/Corvex (Note 17). Approximately $8.4 million was to be reimbursed only if the average closing price of our common shares was at least $26.00 (as adjusted for any share splits or share dividends) during the one year period after the date on which the reimbursement was approved by shareholders, and the remaining approximately $8.4 million will be reimbursed only if the average closing price of our common shares is at least $26.00 (as adjusted for any share splits or share dividends) during the one year period between the first and second anniversaries of the date on which the reimbursement was approved by shareholders. The average closing price of our common shares was at least $26.00 during the first one year period after the date on which the reimbursement was approved by shareholders, and in August 2015, we paid $8.4 million to Related/Corvex. The potential future reimbursement represents a derivative instrument as codified in ASC 815 Derivatives and Hedging which requires the potential future reimbursement to be recorded at fair value at each reporting date. The fair value of the derivative liability as of December 31, 2014 was $6.7 million . The change in the fair value of $4.6 million and $6.9 million , respectively, for the three and nine months ended September 30, 2015 was recorded in general and administrative expenses in our condensed consolidated statement of operations for the three and nine months ended September 30, 2015 . The valuation techniques and significant unobservable inputs used for our level 3 fair value measurement at September 30, 2015 were as follows: Description Fair Value at September 30, 2015 Primary Valuation Technique Unobservable Inputs Rate Derivative liability $ 5,159 Monte Carlo simulation Risk-free rate 0.25% Volatility 20.0% Financial Instruments In addition to the assets and liabilities described in the above table, our financial instruments include our cash and cash equivalents, real estate mortgages receivable, restricted cash, senior unsecured debt and mortgage notes payable. At September 30, 2015 and December 31, 2014, the fair value of these additional financial instruments were not materially different from their carrying values, except as follows (in thousands): September 30, 2015 December 31, 2014 Carrying Amount Fair Value Carrying Amount Fair Value Senior unsecured debt and mortgage notes payable, net $ 1,828,073 $ 1,885,499 $ 2,207,665 $ 2,263,535 The fair values of our senior notes and mortgage notes payable are based on estimates using discounted cash flow analyses and currently prevailing interest rates adjusted by credit risk spreads (level 3 inputs). Our cash and cash equivalents consists of cash maintained in time deposits, depository accounts and money market accounts. From time-to-time we may also invest in various U.S. government securities. We continually monitor the credit ratings of the financial institutions holding our deposits to minimize our exposure to credit risk. Throughout the year, we have cash balances in excess of federally insured limits deposited with various financial institutions. We do not believe we are exposed to any significant credit risk on cash and cash equivalents. Other financial instruments that potentially subject us to concentrations of credit risk consist principally of rents receivable; however, as of September 30, 2015 , no single tenant of ours is responsible for more than 4% of our total annualized rents. Our derivative financial instruments, including interest rate swaps, are entered with major financial institutions and we monitor the amount of credit exposure to any one counterparty.

Earnings Per Common Share

Earnings Per Common Share	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share The following table sets forth the computation of basic and diluted earnings per share (amounts in thousands except per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Numerator for earnings per common share - basic: Income from continuing operations $ 30,466 $ 156,523 $ 56,712 $ 179,936 Preferred distributions (6,981 ) (6,981 ) (20,943 ) (25,114 ) Excess fair value of consideration over carrying vale of preferred shares — — — (16,205 ) Income from continuing operations attributable to Equity Commonwealth common shareholders 23,485 149,542 35,769 138,617 Discontinued operations — 217 — 2,637 Numerator for net income per share - basic $ 23,485 $ 149,759 $ 35,769 $ 141,254 Numerator for earnings per common share - diluted: Income from continuing operations attributable to Equity Commonwealth common shareholders 23,485 149,542 35,769 138,617 Addition of Series D preferred distributions — 1,998 — — Diluted income from continuing operations attributable to Equity Commonwealth common shareholders 23,485 151,540 35,769 138,617 Discontinued operations — 217 — 2,637 Numerator for net income per share - diluted 23,485 151,757 35,769 141,254 Denominator for earnings per common share - basic and diluted: Weighted average number of common shares outstanding - basic 128,739 128,880 129,386 123,736 Weighted average number of common shares outstanding - diluted (1) 129,878 131,243 130,093 123,736 Earnings per share - basic: Income from continuing operations attributable to Equity Commonwealth common shareholders $ 0.18 $ 1.16 $ 0.28 $ 1.12 Discontinued operations — — — 0.02 Net income per share - basic $ 0.18 $ 1.16 $ 0.28 $ 1.14 Earnings per share - diluted: Income from continuing operations attributable to Equity Commonwealth common shareholders $ 0.18 $ 1.16 $ 0.27 $ 1.12 Discontinued operations — — — 0.02 Net income per share - diluted $ 0.18 $ 1.16 $ 0.27 $ 1.14 Anti-dilutive securities: Effect of Series D preferred shares; 6 1/2% cumulative convertible (2) 2,363 — 2,363 4,786 (1) As of September 30, 2015 , we had granted RSUs to certain employees, officers, and the chairman of the Board of Trustees. The RSUs contain both service and market-based vesting components. None of the RSUs have vested. If the market-based vesting component was measured as of September 30, 2015 , 1,139 common shares would be issued to the RSU holders, and no shares would have been issued for the other periods presented. Using a weighted average basis, 1,139 and 707 common shares are reflected in diluted earnings per share for the three and nine months ended September 30, 2015 , respectively. (2) The Series D preferred shares are excluded from the diluted earnings per share calculation because including the Series D preferred shares would also require that the preferred distributions be added back to net income, resulting in anti-dilution during the periods presented.

Segment Information

Segment Information	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Segment Information	Segment Information Our primary business is the ownership and operation of office properties. We have two reportable segments based on our primary method of internal reporting: CBD properties and suburban properties. More than 90% of our revenues from CBD and suburban properties are from office properties. Our operating segments (i.e., our individual properties) are managed and operated consistently in accordance with our standard operating procedures. We use property net operating income, or NOI, to evaluate the performance of our operating segments. We define NOI as income from our real estate including lease termination fees received from tenants less our property operating expenses. NOI excludes amortization of capitalized tenant improvement costs and leasing commissions. As of September 30, 2015 , we owned 24 CBD properties ( 31 buildings) and 43 suburban properties ( 101 buildings), excluding assets held for sale as of September 30, 2015 . Property level information by operating segment as of September 30, 2015 , and for the three and nine months ended September 30, 2015 and 2014 , is as follows (in thousands): As of September 30, 2015 2014 Square feet: CBD properties 13,975 21,892 Suburban properties 11,311 21,027 Total properties(1) 25,286 42,919 (1) Square footage of properties owned as of the respective dates. Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Rental income: CBD properties $ 85,494 $ 109,822 $ 303,686 $ 326,155 Suburban properties 39,965 64,394 153,442 192,508 Total properties $ 125,459 $ 174,216 $ 457,128 $ 518,663 Tenant reimbursements and other income: CBD properties $ 23,054 $ 27,653 $ 80,434 $ 86,359 Suburban properties 10,695 14,726 38,395 44,027 Total properties $ 33,749 $ 42,379 $ 118,829 $ 130,386 NOI: CBD properties $ 53,564 $ 71,596 $ 203,077 $ 216,762 Suburban properties 32,073 45,607 111,752 138,463 Total properties $ 85,637 $ 117,203 $ 314,829 $ 355,225 As of September 30, 2015 , our investments in CBD properties and suburban properties, net of accumulated depreciation, were $2,027.3 million and $1,060.9 million , respectively. The following table includes the reconciliation of NOI to net income, the most directly comparable financial measure under GAAP reported in our condensed consolidated financial statements. We consider NOI to be an appropriate supplemental measure to net income because it may help both investors and management to understand the operations of our properties. We use NOI internally to evaluate individual, regional and combined property level performance, and we believe that NOI provides useful information to investors regarding our results of operations because it reflects only those income and expense items that are incurred at the property level and may facilitate comparisons of our operating performance between periods and with other REITs. NOI does not represent cash generated by operating activities in accordance with GAAP and should not be considered as an alternative to net income, net income attributable to Equity Commonwealth common shareholders, operating income or cash flow from operating activities, determined in accordance with GAAP, or as an indicator of our financial performance or liquidity, nor is this measure necessarily indicative of sufficient cash flow to fund all of our needs. This measure should be considered in conjunction with net income, net income attributable to Equity Commonwealth common shareholders, operating income and cash flow from operating activities as presented in our condensed consolidated statements of operations, condensed consolidated statements of comprehensive income and condensed consolidated statements of cash flows. Other REITs and real estate companies may calculate NOI differently than we do. A reconciliation of NOI to net income for the three and nine months ended September 30, 2015 and 2014 , is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Rental income $ 125,459 $ 174,216 $ 457,128 $ 518,663 Tenant reimbursements and other income 33,749 42,379 118,829 130,386 Operating expenses (73,571 ) (99,392 ) (261,128 ) (293,824 ) NOI $ 85,637 $ 117,203 $ 314,829 $ 355,225 NOI $ 85,637 $ 117,203 $ 314,829 $ 355,225 Depreciation and amortization (40,522 ) (57,213 ) (156,858 ) (168,693 ) General and administrative (16,249 ) (47,450 ) (43,718 ) (96,395 ) Loss on asset impairment — — (17,162 ) (17,922 ) Acquisition related costs — — — (5 ) Operating income 28,866 12,540 97,091 72,210 Interest and other income 637 406 4,813 1,071 Interest expense (25,111 ) (35,245 ) (82,926 ) (111,079 ) (Loss) gain on early extinguishment of debt (3,887 ) 6,699 6,111 6,699 Gain on sale of equity investments — 171,754 — 171,721 Gain on issuance of shares by an equity investee — — — 17,020 Foreign currency exchange loss (9,809 ) — (8,953 ) — Gain on sale of properties 39,793 — 42,953 — Income from continuing operations before income taxes and equity in earnings of investees 30,489 156,154 59,089 157,642 Income tax expense (23 ) (703 ) (2,377 ) (2,166 ) Equity in earnings of investees — 1,072 — 24,460 Income from continuing operations 30,466 156,523 56,712 179,936 Income from discontinued operations — 95 — 8,220 Gain (loss) on asset impairment from discontinued operations — 122 — (2,238 ) Loss on early extinguishment of debt from discontinued operations — — — (3,345 ) Net income $ 30,466 $ 156,740 $ 56,712 $ 182,573

Related Person Transactions

Related Person Transactions	9 Months Ended
	Sep. 30, 2015
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions The following discussion includes a description of our related person transactions for the three and nine months ended September 30, 2015 and 2014 . Certain of these related person transactions, and their approvals, occurred prior to the election of our new Board of Trustees at the Special Meeting and the appointment of our current executive officers following the Special Meeting. The disclosure below under “—Transactions with Prior Related Persons” describes our transactions and approvals with our prior related persons. Related Person Transactions Following the Special Meeting: Equity Group Investments and associated entities: Effective July 20, 2015, we entered into a lease with Two North Riverside Plaza Joint Venture Limited Partnership, an entity associated with Mr. Zell, our Chairman, to occupy office space on the twentieth and twenty-first floors of Two North Riverside Plaza in Chicago, Illinois. The initial term of the lease is approximately five years, with one 5 -year renewal option. The lease payment is approximately $0.5 million for the initial year beginning in 2016, and $0.8 million annually thereafter. This lease was approved by the Audit Committee of the Board of Trustees on June 16, 2015. Effective June 1, 2014, we entered into a one -year license agreement with Equity Group Investments, a private investment firm (Equity Group), to use office space on the sixth floor at Two North Riverside Plaza in Chicago, Illinois. The license fee was $0.2 million for the initial year. The license fee includes the non-exclusive use of additional areas on the sixth floor (such as conference rooms and common areas), certain administrative services (such as mail room services and reception desk staffing), office equipment, office furniture, supplies, licensee’s share of building operating expenses and real estate taxes and access to one parking space. Mr. Zell, our Chairman, is the Chairman and Chief Executive Officer of Equity Group, and Mr. Helfand, our President and Chief Executive Officer, is the Co-President of Equity Group. This license agreement was approved by the Audit Committee of the Board of Trustees and was scheduled to expire on May 31, 2015. On May 4, 2015, the Audit Committee of the Board of Trustees approved an agreement to extend the term of the license agreement through November 30, 2015. The license fee payment is approximately $0.1 million for the extended term. On November 2, 2015, the Audit Committee of the Board of Trustees approved an agreement to extend the term of the license agreement through January 31, 2016, for a maximum license fee payment of approximately $0.1 million . Effective June 1, 2014, we entered into a one -year lease with one 3 -month renewal option with Two North Riverside Plaza Joint Venture Limited Partnership, an entity associated with Mr. Zell, our Chairman, to occupy office space on the fourteenth floor at Two North Riverside Plaza in Chicago, Illinois. The lease payment was $0.2 million for the initial term. This lease was terminated, effective January 31, 2015. This lease was approved by the Audit Committee of the Board of Trustees. Effective July 31, 2014, we entered into a sublease with Equity Residential Management, L.L.C. to occupy office space on the tenth floor of Two North Riverside Plaza in Chicago, Illinois. Equity Residential Management, L.L.C. leases the space from Two North Riverside Plaza Joint Venture Limited Partnership, an entity associated with Mr. Zell, our Chairman. The initial term of the sublease was approximately seven months commencing on or about October 22, 2014, expiring on May 31, 2015, with one 3 -month renewal option. The sublease payment was approximately $0.2 million for the initial term. This sublease was approved by the Audit Committee of the Board of Trustees. On May 4, 2015, the Audit Committee of the Board of Trustees approved an agreement to extend the term of the sublease through November 30, 2015. The sublease payment is approximately $0.2 million for the extended term. On November 2, 2015, the Audit Committee of the Board of Trustees approved an agreement to extend the term of the license agreement through January 31, 2016, for a maximum sublease payment of approximately $0.1 million . Related/Corvex: On July 31, 2014, at the reconvened session of our 2014 annual meeting of shareholders, our shareholders voted to approve the reimbursement of approximately $33.5 million of expenses incurred by Related/Corvex since February 2013 in connection with their consent solicitations to remove our former Trustees and elect the new Board of Trustees and to engage in related litigation. Approximately $16.7 million was paid during the year ended December 31, 2014. Approximately $8.4 million was to be reimbursed only if the average closing price of our common shares is at least $26.00 (as adjusted for any share splits or share dividends) during the one year period after the date on which the reimbursement was approved by shareholders, and the remaining approximately $8.4 million will be reimbursed only if the average closing price of our common shares is at least $26.00 (as adjusted for any share splits or share dividends) during the one year period between the first and second anniversaries of the date on which the reimbursement was approved by shareholders. The average closing price of our common shares was at least $26.00 during the first one year period after the date on which the reimbursement was approved by shareholders, and in August 2015, we paid $8.4 million to Related/Corvex. Transactions with Prior Related Persons: RMR : Prior to entering into the Termination and Cooperation Agreement with RMR, as further described below, we had three primary agreements with RMR and its affiliates to provide management and administrative services to us: (i) a business management agreement, which relates to our business generally, (ii) a property management agreement, which relates to our property level operations, and (iii) an Australia business and property management agreement, which relates to our Australian properties. During the time we were externally managed by RMR, one of our former Managing Trustees, Mr. Barry Portnoy, was Chairman, majority owner and an employee of RMR. Another former Managing Trustee and our former President, Mr. Adam Portnoy, is the son of Mr. Barry Portnoy, and was an owner, President, Chief Executive Officer and a director of RMR. As a result of the removal, effective March 25, 2014, of Mr. Barry Portnoy and Mr. Adam Portnoy as Trustees of the Company and the resignation on May 23, 2014, of Mr. Adam D. Portnoy, Mr. John C. Popeo, Mr. David M. Lepore and other officers of RMR from their respective positions as officers of the Company, they, RMR, RMR Australia Asset Management Pty Limited, or RMR Australia, SIR and AIC have ceased to be related persons of the Company. Therefore, we only present related person transactions with these entities through June 30, 2014. Pursuant to our business management agreement with RMR, we recognized business management fee expense of $31.7 million for the six months ended June 30, 2014. The fees for the six months ended June 30, 2014, include estimated 2014 incentive fees payable in common shares based on our common share total return. These amounts are included in general and administrative expenses, in our condensed consolidated financial statements. In accordance with the terms of our business management agreement, as amended in December 2013, we issued 68,206 of our common shares to RMR for the six months ended June 30, 2014 as payment for 10% of the base business management fee we recognized for such period. In connection with our property management agreement with RMR, the aggregate property management and construction supervision fees we recognized were $13.8 million for the six months ended June 30, 2014. These amounts are included in operating expenses or have been capitalized, as appropriate, in our condensed consolidated financial statements. On January 31, 2013, we entered into a business and property management agreement (Australia Management Agreement) with RMR Australia. RMR Australia is owned by our former Managing Trustees and our former President. RMR has agreed to waive half of the fees payable by us under our property management agreement with RMR and half of the business management fees otherwise payable by us under our business management agreement with RMR related to real estate investments that are subject to the Australia Management Agreement for so long as the Australia Management Agreement is in effect and we or any of our subsidiaries are paying the fees under that agreement. Pursuant to the Australia Management Agreement, we recognized aggregate business and property management fee expense of $0.9 million for the six months ended June 30, 2014, which amounts are equal to the fees waived by RMR and excluded from the amount that was payable to RMR during the six months ended June 30, 2014. Termination and Cooperation Agreement: On September 30, 2014, we entered into a termination and cooperation agreement (Cooperation Agreement) with RMR and RMR Australia (together, Manager). Under the terms of the agreement, the existing business and property management agreements with RMR terminated effective September 30, 2014. Pursuant to the Cooperation Agreement, through February 28, 2015, Manager agreed to use best efforts to assist us in the transition of our management and operations. We paid Manager $1.2 million per month for transition services from October 1, 2014 to February 28, 2015, which included continued management and other services for the Australian assets pursuant to the Australian Management Agreement. Beginning March 1, 2015, we agreed to pay Manager $0.1 million per month until we no longer required such services or until the Australia Management Agreement was terminated, which was terminated in the third quarter of 2015, effective October 31, 2015. There is no future obligation to pay any fees to Manager. SIR : SIR was formerly our 100% owned subsidiary. In March 2012, SIR completed an initial public offering, or the SIR IPO. As of June 30, 2014, we owned 22,000,000 common shares of SIR, which represented approximately 36.7% of SIR’s outstanding common shares. On July 9, 2014, we sold our entire stake of 22,000,000 common shares of SIR, for $32.04 per share, raising aggregate gross proceeds of $704.8 million . As a result of this sale, we no longer hold any interest in SIR. AIC : We previously owned 12.5% of AIC, an Indiana insurance company, and, as of May 9, 2014, had invested $5.2 million in AIC since we became an equity owner of AIC in 2009. RMR, SIR and five other companies to which RMR provides management services also own shares of AIC. The other shareholders of AIC, on May 9, 2014, exercised their right to purchase the 20,000 shares of AIC we then owned. We received $5.8 million in aggregate proceeds from this sale and we no longer own any interest in AIC. We previously purchased property insurance providing $500.0 million of coverage pursuant to an insurance program arranged by AIC and with respect to which AIC was a reinsurer of certain coverage amounts. This program expired in June 2014. Indemnification : Pursuant to our declaration of trust and separate indemnification agreements, we have advanced amounts incurred for legal fees and costs on behalf of certain of the former Trustees and officers with respect to the legal proceedings described in Part II, Item 1, “Legal Proceedings” in this Quarterly Report. Pursuant to indemnification provisions in our business and property management agreements with RMR, we have also incurred legal fees and costs on behalf of RMR for claims brought against RMR in its capacity as our business and property manager with respect to certain legal proceedings described in Part II, Item 1, “Legal Proceedings” in this Quarterly Report. For the six months ended June 30, 2014, we incurred approximately $5.4 million in such legal fees and costs.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2015
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In October 2015, we sold seven properties ( 13 buildings), with 1,263,809 square feet for $131.2 million in a series of transactions (see Note 4). These properties were classified as held for sale as of September 30, 2015.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	The accompanying condensed consolidated financial statements of EQC have been prepared without audit. Certain information and footnote disclosures required by U.S. generally accepted accounting principles, or GAAP, for complete financial statements have been condensed or omitted. We believe the disclosures made are adequate to make the information presented not misleading. However, the accompanying condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes contained in our Annual Report on Form 10-K (Annual Report) for the year ended December 31, 2014. Capitalized terms used, but not defined in this Quarterly Report, have the same meanings as in our Annual Report. In the opinion of our management, all adjustments, which include only normal recurring adjustments considered necessary for a fair presentation, have been included. All intercompany transactions and balances with or among our subsidiaries have been eliminated. Operating results for interim periods are not necessarily indicative of the results that may be expected for the full year. Reclassifications have been made to the prior years’ financial statements to conform to the current year’s presentation. The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect reported amounts. Actual results could differ from those estimates. Significant estimates in the condensed consolidated financial statements include the allowance for doubtful accounts, purchase price allocations, useful lives of fixed assets and impairment of real estate and intangible assets. Share amounts are presented in whole numbers, except where noted.
Recent Accounting Pronouncements	In April 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity, or ASU 2014-08. ASU 2014-08 changes the criteria for reporting a discontinued operation. Under the new pronouncement, a disposal of a part of an organization that has a major effect on its operations and financial results is a discontinued operation. We adopted ASU 2014-08 on January 1, 2015, and determined that our 2015 dispositions and properties held for sale as of September 30, 2015 do not individually represent a strategic shift, as defined by the standard, that has or will have a major effect on our operations and financial results. As a result, the 2015 dispositions have not been presented as discontinued operations in the 2015 statements of operations. In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers, which provides guidance for revenue recognition. This update is effective for interim and annual reporting periods beginning after December 15, 2017. We are currently in the process of evaluating the impact, if any, the adoption of this ASU will have on our condensed consolidated financial statements. In April 2015, the FASB issued ASU No. 2015-03, Simplifying the Presentation of Debt Issuance Costs. This standard amends existing guidance to require the presentation of debt issuance costs in the balance sheet as a deduction from the carrying amount of the related debt liability instead of as a deferred charge. It is effective for annual reporting periods beginning after December 15, 2015, but early adoption is permitted. We do not expect that the adoption of this standard will have a material impact on our condensed consolidated financial statements.

Real Estate Properties (Tables)

Real Estate Properties (Tables)	9 Months Ended
	Sep. 30, 2015
Real Estate [Abstract]
Summary of Properties Held for Sale and Balance Sheet Information for all Properties Classified as Held for sale	As of September 30, 2015 , we classified the following properties as held for sale (dollars in thousands): Asset Date Sold Segment Number of Number of Square Footage Gross Sales Price Properties One South Church Avenue October 2015 CBD 1 1 240,811 $ 32,000 775 Ridge Lake Boulevard October 2015 CBD 1 1 120,678 16,300 One Park Square October 2015 CBD 1 6 259,737 34,300 Portfolio of Properties 9040 Roswell Road October 2015 Suburban 1 1 178,941 The Exchange October 2015 Suburban 1 2 187,632 3920 Arkwright Road October 2015 Suburban 1 1 196,156 1775 West Oak Commons Court October 2015 Suburban 1 1 79,854 Georgia portfolio 4 5 642,583 $ 48,550 7 13 1,263,809 $ 131,150 Summarized balance sheet information for all properties classified as held for sale is as follows (in thousands): September 30, 2015 Real estate properties $ 108,023 Other assets, net 4,127 Properties held for sale $ 112,150 Accounts payable and accrued expenses $ 1,479 Security deposits 430 Liabilities related to properties held for sale $ 1,909
Summary of Properties Sold and Income Statement Information for Properties Disposed of	Summarized income statement information for properties included in discontinued operations is as follows (in thousands): Three Months Ended Nine Months Ended September 30, 2014 Rental income $ (16 ) $ 14,220 Tenant reimbursements and other income 407 1,730 Total revenues 391 15,950 Operating expenses 261 7,115 General and administrative 6 9 Total expenses 267 7,124 Operating income 124 8,826 Interest and other income 2 2 Interest expense (31 ) (608 ) Income from discontinued operations $ 95 $ 8,220 During the nine months ended September 30, 2015 , we disposed of the following properties (dollars in thousands): Asset Date Disposed Segment Number of Number of Square Footage Gross Sales Price Gain (Loss) on Sale Properties 11350 North Meridian Street January 2015 Suburban 1 1 72,264 $ 4,200 $ 766 333 Laurel Oak Drive (1) March 2015 Suburban — 1 27,164 2,450 251 1921 E. Alton Avenue March 2015 Suburban 1 1 67,846 14,533 4,850 46 Inverness Center Parkway April 2015 Suburban — — — 2,000 1,857 225 Water Street (2) May 2015 CBD 1 1 318,997 — — Sorrento Valley Business Park June 2015 Suburban 1 4 105,003 23,500 11,896 Illinois Center August 2015 CBD 1 2 2,090,162 376,000 26,929 16th and Race Street August 2015 CBD 1 1 608,625 43,000 7,922 185 Asylum Street September 2015 CBD 1 1 868,395 113,250 17,619 Portfolio of properties 7450 Campus Drive May 2015 Suburban 1 1 77,411 129 Worthington Ridge Road May 2015 Suburban 1 1 227,500 599 Research Parkway May 2015 Suburban 1 1 48,249 181 Marsh Hill Road May 2015 Suburban 1 1 162,036 101 Barnes Road May 2015 Suburban 1 1 45,755 15 Sterling Drive May 2015 Suburban 1 1 173,015 35 Thorpe Avenue May 2015 Suburban 1 1 79,862 50 Barnes Industrial Road North May 2015 Suburban 1 1 154,255 5-9 Barnes Industrial Road May 2015 Suburban 1 1 38,006 860 North Main Street May 2015 Suburban 1 1 31,165 One Barnes Industrial Road South May 2015 Suburban 1 1 30,170 Village Lane May 2015 Suburban 1 2 58,185 100 Northfield Drive May 2015 Suburban 1 1 116,986 905 Meridian Lake Drive May 2015 Suburban 1 1 74,652 1717 Deerfield Road May 2015 Suburban 1 1 141,186 1955 West Field Court May 2015 Suburban 1 1 59,130 5015 S. Water Circle May 2015 Suburban 1 1 113,524 Adams Place May 2015 Suburban 1 2 230,259 Cabot Business Park May 2015 Suburban 1 2 252,755 2300 Crown Colony Drive May 2015 Suburban 1 1 45,974 Myles Standish Industrial Park May 2015 Suburban 1 2 74,800 340 Thompson Road May 2015 Suburban 1 1 25,000 100 South Charles Street May 2015 CBD 1 1 159,616 6710 Oxon Hill May 2015 Suburban 1 1 118,336 8800 Queen Avenue South May 2015 Suburban 1 1 280,822 9800 Sherlard Parkway May 2015 Suburban 1 1 46,765 Rosedale Corporate Plaza May 2015 Suburban 1 3 149,116 1000 Shelard Parkway May 2015 Suburban 1 1 62,499 525 Park Street May 2015 CBD 1 1 75,636 Asset Date Disposed Segment Number of Number of Square Footage Gross Sales Price Gain (Loss) on Sale 1900 Meyer Drury Drive May 2015 Suburban 1 1 65,225 131-165 West Ninth Street May 2015 Suburban 1 1 75,517 7-9 Vreeland Road May 2015 Suburban 1 1 155,891 5 Paragon Drive May 2015 Suburban 1 1 119,089 1000 Vorhees Drive and 400 Laurel Oak Drive(1) May 2015 Suburban 1 2 125,415 1601 Veterans Highway May 2015 Suburban 1 1 63,608 Two Corporate Center Drive May 2015 Suburban 1 1 291,230 11311 Cornell Park Drive May 2015 Suburban 1 1 93,413 5300 Kings Island Drive May 2015 Suburban 1 1 159,421 3 Crown Point Court May 2015 Suburban 1 1 73,987 515 Pennsylvania Avenue May 2015 Suburban 1 1 82,000 443 Gulph Road May 2015 Suburban 1 1 21,000 4350 Northern Pike May 2015 Suburban 1 1 503,885 Thunderbolt Place May 2015 Suburban 1 2 100,505 6160 Kempsville Circle May 2015 Suburban 1 1 129,565 448 Viking Drive May 2015 Suburban 1 1 75,374 Portfolio of small office and industrial assets 45 53 5,287,790 $ 376,000 $ (8,075 ) 2501 20th Place South June 2015 CBD 1 1 125,722 420 20th Street North June 2015 CBD 1 1 514,893 Inverness Center June 2015 Suburban 1 4 475,882 701 Poydras Street June 2015 CBD 1 1 1,256,971 300 North Greene Street June 2015 CBD 1 1 324,305 1320 Main Street June 2015 CBD 1 1 334,075 AL, LA, NC, SC office portfolio 6 9 3,031,848 $ 417,450 $ 41,596 12655 Olive Boulevard June 2015 Suburban 1 1 98,588 1285 Fern Ridge Parkway June 2015 Suburban 1 1 66,510 St. Louis portfolio 2 2 165,098 $ 14,300 $ (2,349 ) 310-314 Invermay Road (3) April 2015 Suburban 1 1 47,480 253-293 George Town Road (3) April 2015 Suburban 1 1 143,914 7 Modal Crescent June 2015 Suburban 1 1 164,160 71-93 Whiteside Road June 2015 Suburban 1 1 303,488 9-13 Titanium Court June 2015 Suburban 1 1 69,664 16 Rodborough Road June 2015 Suburban 1 1 90,525 22 Rodborough Road June 2015 Suburban 1 1 43,427 127-161 Cherry Lane June 2015 Suburban 1 1 278,570 310-320 Pitt Street June 2015 CBD 1 1 313,865 44-46 Mandarin Street June 2015 Suburban 1 1 226,718 19 Leadership Way June 2015 Suburban 1 1 76,714 Australia portfolio(4) 11 11 1,758,525 $ 232,955 $ (47,851 ) Asset Date Disposed Segment Number of Number of Square Footage Gross Sales Price Gain (Loss) on Sale Widewaters Parkway August 2015 Suburban 1 8 514,241 5062 Brittonfield Parkway August 2015 Suburban 1 1 40,162 Woodcliff Drive August 2015 Suburban 1 6 516,760 Interstate Place August 2015 Suburban 1 2 61,399 1000 Pittsford - Victor Road August 2015 Suburban 1 1 73,358 1200 Pittsford - Victor Road August 2015 Suburban 1 1 18,900 Corporate Crossing August 2015 Suburban 1 5 216,126 Canal View Boulevard August 2015 Suburban 1 3 118,375 14 Classic Street August 2015 Suburban 1 1 37,084 110 W Fayette Street August 2015 CBD 1 1 304,906 251 Salina Meadows Parkway August 2015 Suburban 1 1 65,617 Upstate New York portfolio 11 30 1,966,928 $ 104,625 $ (12,458 ) 82 117 16,368,645 $ 1,724,263 $ 42,953 (1) This property contains three buildings. We sold one building in March 2015 and two buildings in May 2015. (2) Title to this property was transferred to the lender pursuant to a consensual foreclosure in full satisfaction of the mortgage debt with a principal balance of $40.1 million , resulting in a gain on early extinguishment of debt of $17.3 million for the nine months ended September 30, 2015. See Note 8 for additional information. (3) These properties were sold in a separate transaction to a different buyer than other Australian properties. (4) The loss on sale includes a $63.2 million cumulative foreign currency translation adjustment reclassified from cumulative other comprehensive loss due to the disposition of the Australian portfolio.

Equity Investments (Tables)

Equity Investments (Tables)	9 Months Ended
	Sep. 30, 2015
SIR
Equity Investments
Summary of Unaudited Income Statement Information of Equity Method Investee	The following unaudited summarized income statement information of SIR for the period from July 1, 2014 through July 9, 2014 and for the period from January 1, 2014 through July 9, 2014 is as follows (in thousands, except per share data): For the Period from July 1, 2014 through July 9, 2014 For the Period from January 1, 2014 through July 9, 2014 Rental income $ 4,698 98,226 Tenant reimbursements and other income 923 16,980 Total revenues 5,621 115,206 Operating expenses 1,018 20,982 Depreciation and amortization 1,043 20,832 Acquisition related costs — 374 General and administrative 357 7,731 Total expenses 2,418 49,919 Operating income 3,203 65,287 Interest expense (295 ) (7,287 ) Gain on early extinguishment of debt — 243 Income before income tax expense and equity in earnings of an investee 2,908 58,243 Income tax expense — (90 ) Equity in earnings of an investee 11 32 Net income $ 2,919 $ 58,185 Weighted average common shares outstanding 59,889 52,394 Net income per common share $ 0.05 $ 1.11

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2015
Stockholders' Equity Note [Abstract]
Schedule of Declared Distributions	In 2015, our Board of Trustees declared distributions on our series D preferred shares and series E cumulative redeemable preferred shares to date as follows: Declaration Date Record Date Payment Date Series D Dividend Per Share Series E Dividend Per Share January 16, 2015 February 2, 2015 February 17, 2015 $ 0.40625 $ 0.453125 April 8, 2015 May 1, 2015 May 15, 2015 $ 0.40625 $ 0.453125 July 9, 2015 July 31, 2015 August 17, 2015 $ 0.40625 $ 0.453125 October 9, 2015 November 2, 2015 November 16, 2015 $ 0.40625 $ 0.453125

Cumulative Other Comprehensiv30

Cumulative Other Comprehensive Loss (Tables)	9 Months Ended
	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of Amounts Recognized in Cumulative Other Comprehensive Loss	The following tables present the amounts recognized in cumulative other comprehensive loss by component for the three and nine months ended September 30, 2015 (in thousands): Three Months Ended September 30, 2015 Unrealized Loss on Derivative Instruments and Other Assets Foreign Currency Translation Adjustments Total Balances as of July 1, 2015 $ (5,963 ) $ — $ (5,963 ) Other comprehensive loss before reclassifications (418 ) — (418 ) Amounts reclassified from cumulative other comprehensive loss to net income 1,239 — 1,239 Net current period other comprehensive income 821 — 821 Balances as of September 30, 2015 $ (5,142 ) $ — $ (5,142 ) Nine Months Ended September 30, 2015 Unrealized Loss on Derivative Instruments and Other Assets Foreign Currency Translation Adjustments Total Balances as of January 1, 2015 $ (4,299 ) $ (48,917 ) $ (53,216 ) Other comprehensive loss before reclassifications (1,461 ) (14,290 ) (15,751 ) Amounts reclassified from cumulative other comprehensive loss to net income 618 63,207 63,825 Net current period other comprehensive (loss) income (843 ) 48,917 48,074 Balances as of September 30, 2015 $ (5,142 ) $ — $ (5,142 )
Schedule of Reclassifications Out of Cumulative Other Comprehensive Loss	The following tables present reclassifications out of cumulative other comprehensive loss for the three and nine months ended September 30, 2015 (in thousands): Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income Details about Cumulative Other Comprehensive Loss Components Three Months Ended September 30, 2015 Nine Months Ended September 30, 2015 Affected Line Items in the Statement of Operations Interest rate swap contracts $ 1,239 $ 3,698 Interest expense Foreign currency translation adjustment activity — 63,207 Gain on sale of properties Realized gain on available for sale securities — (3,080 ) Interest and other income $ 1,239 $ 63,825

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2015
Income Tax Disclosure [Abstract]
Schedule of Provision for Income Taxes	Our provision for income taxes consists of the following (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Current: State $ 90 $ 39 $ 270 $ 300 Federal — — 525 — Foreign (67 ) 664 2,337 1,866 23 703 3,132 2,166 Deferred: Foreign — — (755 ) — — — (755 ) — Income tax expense $ 23 $ 703 $ 2,377 $ 2,166

Derivative Instruments (Tables)

Derivative Instruments (Tables)	9 Months Ended
	Sep. 30, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Interest Rate Derivatives Designated as Cash Flow Hedges of Interest Rate Risk	As of September 30, 2015 , we had the following outstanding interest rate derivatives that were designated as cash flow hedges of interest rate risk: Interest Rate Derivative Number of Instruments Notional Amount (in thousands) Interest rate swap 2 $170,097
Schedule of Fair Value of Derivative Financial Instruments	The table below presents the fair value of our derivative financial instruments as well as their classification on the condensed consolidated balance sheets as of September 30, 2015 and December 31, 2014 (amounts in thousands): Fair Value as of Interest Rate Derivative Designated as Hedging Instrument Balance Sheet Location September 30, December 31, Pay-fixed swaps Accounts payable and accrued expenses $ 5,142 $ 7,462
Schedule of Gain or Loss Recognized on Interest Rate Derivatives Designated as Cash Flow Hedges	The table below details the location in the financial statements of the gain or loss recognized on interest rate derivatives designated as cash flow hedges for the three and nine months ended September 30, 2015 and 2014 (amounts in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Balance at beginning of period $ (5,963 ) $ (10,079 ) $ (7,462 ) $ (11,706 ) Amount of (loss) gain recognized in cumulative other comprehensive loss (418 ) 537 (1,378 ) (324 ) Amount of loss reclassified from cumulative other comprehensive loss into interest expense 1,239 1,268 3,698 3,756 Unrealized gain on derivative instruments 821 1,805 2,320 3,432 Balance at end of period $ (5,142 ) $ (8,274 ) $ (5,142 ) $ (8,274 )

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2015
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Summary of Assumptions and Fair Values for Restricted Stock Units Granted in the Period	The assumptions and fair values for the RSUs granted for the nine months ended September 30, 2015 are included in the following table on a per share basis. 2015 Fair value of RSUs granted $ 38.55 Expected term (years) 4 Expected volatility — Expected dividend yield 1.88 % Risk-free rate 0.81 %

Fair Value of Assets and Liab34

Fair Value of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2015
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value	The table below presents certain of our assets and liabilities measured at fair value during 2015 , categorized by the level of inputs used in the valuation of each asset and liability (dollars in thousands): Fair Value at September 30, 2015 Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Description Total (Level 1) (Level 2) (Level 3) Recurring Fair Value Measurements: Effective portion of interest rate swap contracts $ (5,142 ) $ — $ (5,142 ) $ — Derivative liability (5,159 ) — — (5,159 )
Schedule of Valuation Techniques and Significant Unobservable Inputs used for Level 3 Fair Value Measurements	The valuation techniques and significant unobservable inputs used for our level 3 fair value measurement at September 30, 2015 were as follows: Description Fair Value at September 30, 2015 Primary Valuation Technique Unobservable Inputs Rate Derivative liability $ 5,159 Monte Carlo simulation Risk-free rate 0.25% Volatility 20.0%
Schedule of Fair Value and Carrying Value of Financial Instruments	At September 30, 2015 and December 31, 2014, the fair value of these additional financial instruments were not materially different from their carrying values, except as follows (in thousands): September 30, 2015 December 31, 2014 Carrying Amount Fair Value Carrying Amount Fair Value Senior unsecured debt and mortgage notes payable, net $ 1,828,073 $ 1,885,499 $ 2,207,665 $ 2,263,535

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	9 Months Ended
	Sep. 30, 2015
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted earnings per share (amounts in thousands except per share amounts): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Numerator for earnings per common share - basic: Income from continuing operations $ 30,466 $ 156,523 $ 56,712 $ 179,936 Preferred distributions (6,981 ) (6,981 ) (20,943 ) (25,114 ) Excess fair value of consideration over carrying vale of preferred shares — — — (16,205 ) Income from continuing operations attributable to Equity Commonwealth common shareholders 23,485 149,542 35,769 138,617 Discontinued operations — 217 — 2,637 Numerator for net income per share - basic $ 23,485 $ 149,759 $ 35,769 $ 141,254 Numerator for earnings per common share - diluted: Income from continuing operations attributable to Equity Commonwealth common shareholders 23,485 149,542 35,769 138,617 Addition of Series D preferred distributions — 1,998 — — Diluted income from continuing operations attributable to Equity Commonwealth common shareholders 23,485 151,540 35,769 138,617 Discontinued operations — 217 — 2,637 Numerator for net income per share - diluted 23,485 151,757 35,769 141,254 Denominator for earnings per common share - basic and diluted: Weighted average number of common shares outstanding - basic 128,739 128,880 129,386 123,736 Weighted average number of common shares outstanding - diluted (1) 129,878 131,243 130,093 123,736 Earnings per share - basic: Income from continuing operations attributable to Equity Commonwealth common shareholders $ 0.18 $ 1.16 $ 0.28 $ 1.12 Discontinued operations — — — 0.02 Net income per share - basic $ 0.18 $ 1.16 $ 0.28 $ 1.14 Earnings per share - diluted: Income from continuing operations attributable to Equity Commonwealth common shareholders $ 0.18 $ 1.16 $ 0.27 $ 1.12 Discontinued operations — — — 0.02 Net income per share - diluted $ 0.18 $ 1.16 $ 0.27 $ 1.14 Anti-dilutive securities: Effect of Series D preferred shares; 6 1/2% cumulative convertible (2) 2,363 — 2,363 4,786 (1) As of September 30, 2015 , we had granted RSUs to certain employees, officers, and the chairman of the Board of Trustees. The RSUs contain both service and market-based vesting components. None of the RSUs have vested. If the market-based vesting component was measured as of September 30, 2015 , 1,139 common shares would be issued to the RSU holders, and no shares would have been issued for the other periods presented. Using a weighted average basis, 1,139 and 707 common shares are reflected in diluted earnings per share for the three and nine months ended September 30, 2015 , respectively. (2) The Series D preferred shares are excluded from the diluted earnings per share calculation because including the Series D preferred shares would also require that the preferred distributions be added back to net income, resulting in anti-dilution during the periods presented.

Segment Information (Tables)

Segment Information (Tables)	9 Months Ended
	Sep. 30, 2015
Segment Reporting [Abstract]
Schedule of Property Level Information by Operating Segment	Property level information by operating segment as of September 30, 2015 , and for the three and nine months ended September 30, 2015 and 2014 , is as follows (in thousands): As of September 30, 2015 2014 Square feet: CBD properties 13,975 21,892 Suburban properties 11,311 21,027 Total properties(1) 25,286 42,919 (1) Square footage of properties owned as of the respective dates. Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Rental income: CBD properties $ 85,494 $ 109,822 $ 303,686 $ 326,155 Suburban properties 39,965 64,394 153,442 192,508 Total properties $ 125,459 $ 174,216 $ 457,128 $ 518,663 Tenant reimbursements and other income: CBD properties $ 23,054 $ 27,653 $ 80,434 $ 86,359 Suburban properties 10,695 14,726 38,395 44,027 Total properties $ 33,749 $ 42,379 $ 118,829 $ 130,386 NOI: CBD properties $ 53,564 $ 71,596 $ 203,077 $ 216,762 Suburban properties 32,073 45,607 111,752 138,463 Total properties $ 85,637 $ 117,203 $ 314,829 $ 355,225
Schedule of Reconciliation of NOI to Net Income	A reconciliation of NOI to net income for the three and nine months ended September 30, 2015 and 2014 , is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2015 2014 2015 2014 Rental income $ 125,459 $ 174,216 $ 457,128 $ 518,663 Tenant reimbursements and other income 33,749 42,379 118,829 130,386 Operating expenses (73,571 ) (99,392 ) (261,128 ) (293,824 ) NOI $ 85,637 $ 117,203 $ 314,829 $ 355,225 NOI $ 85,637 $ 117,203 $ 314,829 $ 355,225 Depreciation and amortization (40,522 ) (57,213 ) (156,858 ) (168,693 ) General and administrative (16,249 ) (47,450 ) (43,718 ) (96,395 ) Loss on asset impairment — — (17,162 ) (17,922 ) Acquisition related costs — — — (5 ) Operating income 28,866 12,540 97,091 72,210 Interest and other income 637 406 4,813 1,071 Interest expense (25,111 ) (35,245 ) (82,926 ) (111,079 ) (Loss) gain on early extinguishment of debt (3,887 ) 6,699 6,111 6,699 Gain on sale of equity investments — 171,754 — 171,721 Gain on issuance of shares by an equity investee — — — 17,020 Foreign currency exchange loss (9,809 ) — (8,953 ) — Gain on sale of properties 39,793 — 42,953 — Income from continuing operations before income taxes and equity in earnings of investees 30,489 156,154 59,089 157,642 Income tax expense (23 ) (703 ) (2,377 ) (2,166 ) Equity in earnings of investees — 1,072 — 24,460 Income from continuing operations 30,466 156,523 56,712 179,936 Income from discontinued operations — 95 — 8,220 Gain (loss) on asset impairment from discontinued operations — 122 — (2,238 ) Loss on early extinguishment of debt from discontinued operations — — — (3,345 ) Net income $ 30,466 $ 156,740 $ 56,712 $ 182,573

Board of Trustees - Narrative (

Board of Trustees - Narrative (Details) - trustee	Jun. 16, 2015	Jul. 31, 2014	May. 23, 2014	Feb. 18, 2014
Board of Trustees
Minimum holders of outstanding common shares consented to the proposal, reaching the required threshold (as a percent)				66.67%
Number of trustees elected		7	7
Total number of trustees	11	11

Real Estate Properties - Narrat

Real Estate Properties - Narrative (Details) $ in Thousands	Jun. 27, 2014USD ($)ft²propertybuilding	Jan. 31, 2013propertybuilding	Sep. 30, 2015USD ($)ft²	Sep. 30, 2014USD ($)ft²	Sep. 30, 2015USD ($)ft²propertybuilding	Sep. 30, 2014USD ($)ft²	Dec. 31, 2014property
Real Estate Properties [Line Items]
Real estate improvements					$ 46,700	$ 65,900
Number of properties held for sale | property							0
Number of properties sold or agreed to be sold | property		3
Number of buildings sold | building		18
Property square feet | ft²			25,286,000	42,919,000	25,286,000	42,919,000
Loss on asset impairment			$ 0	$ 122	$ 0	$ (2,238)
Loss on early extinguishment of debt			$ 0	$ 0	$ 0	$ (3,345)
Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties sold or agreed to be sold | property					82
Number of buildings sold | building					117
Property square feet | ft²			16,368,645		16,368,645
CBD | Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties sold or agreed to be sold | property	1
Number of buildings sold | building	2
Suburban property | Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties sold or agreed to be sold | property	13
Number of buildings sold | building	41
CBD and suburban properties | Disposed of by Sale
Real Estate Properties [Line Items]
Property square feet | ft²	2,784,098
Proceeds from sale of real estate	$ 215,900
Loss on asset impairment	2,400
Loss on early extinguishment of debt	$ 3,300

Real Estate Properties - Summar

Real Estate Properties - Summary of Properties Held for Sale (Details) $ in Thousands	Sep. 30, 2015USD ($)ft²propertybuilding	Dec. 31, 2014property	Sep. 30, 2014ft²
Real Estate Properties [Line Items]
Number of Properties | property		0
Square Footage (in sqft)	25,286,000		42,919,000
Held-for-sale
Real Estate Properties [Line Items]
Number of Properties | property	7
Number of Buildings | building	13
Square Footage (in sqft)	1,263,809
Gross Sales Price | $	$ 131,150
Held-for-sale | Georgia Portfolio
Real Estate Properties [Line Items]
Number of Properties | property	4
Number of Buildings | building	5
Square Footage (in sqft)	642,583
Gross Sales Price | $	$ 48,550
Held-for-sale | CBD | One South Church Avenue
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft)	240,811
Gross Sales Price | $	$ 32,000
Held-for-sale | CBD | 775 Ridge Lake Boulevard
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft)	120,678
Gross Sales Price | $	$ 16,300
Held-for-sale | CBD | One Park Square
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	6
Square Footage (in sqft)	259,737
Gross Sales Price | $	$ 34,300
Held-for-sale | Suburban property | 9040 Roswell Road
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft)	178,941
Held-for-sale | Suburban property | The Exchange
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	2
Square Footage (in sqft)	187,632
Held-for-sale | Suburban property | 3920 Arkwright Road
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft)	196,156
Held-for-sale | Suburban property | 1775 West Oak Commons Court
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft)	79,854

Real Estate Properties - Summ40

Real Estate Properties - Summary of Balance Sheet Information for all Properties Classified as Held for sale (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities related to properties held for sale	$ 1,909	$ 0
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate properties	108,023
Other assets, net	4,127
Properties held for sale	112,150
Accounts payable and accrued expenses	1,479
Security deposits	430
Liabilities related to properties held for sale	$ 1,909

Real Estate Properties - Summ41

Real Estate Properties - Summary of Properties Sold (Details) $ in Thousands	Jun. 27, 2014propertybuilding	Sep. 30, 2015USD ($)ft²propertybuilding	Aug. 31, 2015USD ($)ft²propertybuilding	Jun. 30, 2015USD ($)ft²propertybuilding	May. 31, 2015USD ($)ft²propertybuilding	Apr. 30, 2015USD ($)ft²propertybuilding	Mar. 31, 2015USD ($)ft²propertybuilding	Jan. 31, 2015USD ($)ft²propertybuilding	Jan. 31, 2013propertybuilding	Sep. 30, 2015USD ($)ft²	Jun. 30, 2015USD ($)ft²propertybuilding	May. 31, 2015ft²building	Sep. 30, 2014USD ($)ft²	Sep. 30, 2015USD ($)ft²propertybuilding	Sep. 30, 2014USD ($)ft²
Real Estate Properties [Line Items]
Number of Properties | property									3
Number of Buildings									18
Square Footage (in sqft) | ft²		25,286,000								25,286,000			42,919,000	25,286,000	42,919,000
Gain (Loss) on Sale | $										$ 39,793			$ 0	$ 42,953	$ 0
333 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of Buildings												3
1000 Vorhees Drive and 400 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of Buildings												3
Disposed of by Sale
Real Estate Properties [Line Items]
Number of Properties | property														82
Number of Buildings														117
Square Footage (in sqft) | ft²		16,368,645								16,368,645				16,368,645
Gross Sales Price | $														$ 1,724,263
Gain (Loss) on Sale | $														$ 42,953
Disposed of by Sale | 333 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of Buildings					2		1
Disposed of by Sale | 1000 Vorhees Drive and 400 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of Buildings					2		1
Disposed of by Sale | Portfolio of Small Office and Industrial Assets
Real Estate Properties [Line Items]
Number of Properties | property					45
Number of Buildings					53
Square Footage (in sqft) | ft²					5,287,790							5,287,790
Gross Sales Price | $					$ 376,000
Gain (Loss) on Sale | $					$ (8,075)
Disposed of by Sale | AL, LA, NC, SC Office Portfolio
Real Estate Properties [Line Items]
Number of Properties | property				6
Number of Buildings				9
Square Footage (in sqft) | ft²				3,031,848							3,031,848
Gross Sales Price | $				$ 417,450
Gain (Loss) on Sale | $				$ 41,596
Disposed of by Sale | St. Louis Portfolio
Real Estate Properties [Line Items]
Number of Properties | property				2
Number of Buildings				2
Square Footage (in sqft) | ft²				165,098							165,098
Gross Sales Price | $				$ 14,300
Gain (Loss) on Sale | $				$ (2,349)
Disposed of by Sale | Australia Portfolio
Real Estate Properties [Line Items]
Number of Properties | property											11
Number of Buildings											11
Square Footage (in sqft) | ft²				1,758,525							1,758,525
Gross Sales Price | $											$ 232,955
Gain (Loss) on Sale | $											$ (47,851)
Disposed of by Sale | Upstate New York Portfolio
Real Estate Properties [Line Items]
Number of Properties | property			11
Number of Buildings			30
Square Footage (in sqft) | ft²			1,966,928
Gross Sales Price | $			$ 104,625
Gain (Loss) on Sale | $			$ (12,458)
Disposed of by Sale | Suburban property
Real Estate Properties [Line Items]
Number of Properties | property	13
Number of Buildings	41
Disposed of by Sale | Suburban property | 11350 North Meridian Street
Real Estate Properties [Line Items]
Number of Properties | property								1
Number of Buildings								1
Square Footage (in sqft) | ft²								72,264
Gross Sales Price | $								$ 4,200
Gain (Loss) on Sale | $								$ 766
Disposed of by Sale | Suburban property | 333 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of Properties | property							0
Number of Buildings							1
Square Footage (in sqft) | ft²							27,164
Gross Sales Price | $							$ 2,450
Gain (Loss) on Sale | $							$ 251
Disposed of by Sale | Suburban property | 1921 E. Alton Avenue
Real Estate Properties [Line Items]
Number of Properties | property							1
Number of Buildings							1
Square Footage (in sqft) | ft²							67,846
Gross Sales Price | $							$ 14,533
Gain (Loss) on Sale | $							$ 4,850
Disposed of by Sale | Suburban property | 46 Inverness Center Parkway
Real Estate Properties [Line Items]
Number of Properties | property						0
Number of Buildings						0
Square Footage (in sqft) | ft²						0
Gross Sales Price | $						$ 2,000
Gain (Loss) on Sale | $						$ 1,857
Disposed of by Sale | Suburban property | Sorrento Valley Business Park
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				4
Square Footage (in sqft) | ft²				105,003							105,003
Gross Sales Price | $				$ 23,500
Gain (Loss) on Sale | $				$ 11,896
Disposed of by Sale | Suburban property | 7450 Campus Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					77,411							77,411
Disposed of by Sale | Suburban property | 129 Worthington Ridge Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					227,500							227,500
Disposed of by Sale | Suburban property | 599 Research Parkway
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					48,249							48,249
Disposed of by Sale | Suburban property | 181 Marsh Hill Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					162,036							162,036
Disposed of by Sale | Suburban property | 101 Barnes Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					45,755							45,755
Disposed of by Sale | Suburban property | 15 Sterling Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					173,015							173,015
Disposed of by Sale | Suburban property | 35 Thorpe Avenue
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					79,862							79,862
Disposed of by Sale | Suburban property | 50 Barnes Industrial Road North
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					154,255							154,255
Disposed of by Sale | Suburban property | 5-9 Barnes Industrial Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					38,006							38,006
Disposed of by Sale | Suburban property | 860 North Main Street
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					31,165							31,165
Disposed of by Sale | Suburban property | One Barnes Industrial Road South
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					30,170							30,170
Disposed of by Sale | Suburban property | Village Lane
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					2
Square Footage (in sqft) | ft²					58,185							58,185
Disposed of by Sale | Suburban property | 100 Northfield Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					116,986							116,986
Disposed of by Sale | Suburban property | 905 Meridian Lake Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					74,652							74,652
Disposed of by Sale | Suburban property | 1717 Deerfield Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					141,186							141,186
Disposed of by Sale | Suburban property | 1955 West Field Court
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					59,130							59,130
Disposed of by Sale | Suburban property | 5015 S. Water Circle
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					113,524							113,524
Disposed of by Sale | Suburban property | Adams Place
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					2
Square Footage (in sqft) | ft²					230,259							230,259
Disposed of by Sale | Suburban property | Cabot Business Park
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					2
Square Footage (in sqft) | ft²					252,755							252,755
Disposed of by Sale | Suburban property | 2300 Crown Colony Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					45,974							45,974
Disposed of by Sale | Suburban property | Myles Standish Industrial Park
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					2
Square Footage (in sqft) | ft²					74,800							74,800
Disposed of by Sale | Suburban property | 340 Thompson Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					25,000							25,000
Disposed of by Sale | Suburban property | 6710 Oxon Hill
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					118,336							118,336
Disposed of by Sale | Suburban property | 8800 Queen Avenue South
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					280,822							280,822
Disposed of by Sale | Suburban property | 9800 Sherlard Parkway
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					46,765							46,765
Disposed of by Sale | Suburban property | Rosedale Corporate Plaza
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					3
Square Footage (in sqft) | ft²					149,116							149,116
Disposed of by Sale | Suburban property | 1000 Shelard Parkway
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					62,499							62,499
Disposed of by Sale | Suburban property | 1900 Meyer Drury Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					65,225							65,225
Disposed of by Sale | Suburban property | 131-165 West Ninth Street
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					75,517							75,517
Disposed of by Sale | Suburban property | 7-9 Vreeland Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					155,891							155,891
Disposed of by Sale | Suburban property | 5 Paragon Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					119,089							119,089
Disposed of by Sale | Suburban property | 1000 Vorhees Drive and 400 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					2
Square Footage (in sqft) | ft²					125,415							125,415
Disposed of by Sale | Suburban property | 1601 Veterans Highway
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					63,608							63,608
Disposed of by Sale | Suburban property | Two Corporate Center Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					291,230							291,230
Disposed of by Sale | Suburban property | 11311 Cornell Center Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					93,413							93,413
Disposed of by Sale | Suburban property | 5300 Kings Island Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					159,421							159,421
Disposed of by Sale | Suburban property | 3 Crown Point Court
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					73,987							73,987
Disposed of by Sale | Suburban property | 515 Pennsylvania Avenue
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					82,000							82,000
Disposed of by Sale | Suburban property | 443 Gulph Road
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					21,000							21,000
Disposed of by Sale | Suburban property | 4350 Northern Pike
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					503,885							503,885
Disposed of by Sale | Suburban property | Thunderbolt Place
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					2
Square Footage (in sqft) | ft²					100,505							100,505
Disposed of by Sale | Suburban property | 6160 Kempsville Circle
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					129,565							129,565
Disposed of by Sale | Suburban property | 448 Viking Drive
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					75,374							75,374
Disposed of by Sale | Suburban property | Inverness Center
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				4
Square Footage (in sqft) | ft²				475,882							475,882
Disposed of by Sale | Suburban property | 12655 Olive Boulevard
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				98,588							98,588
Disposed of by Sale | Suburban property | 1285 Fern Ridge Parkway
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				66,510							66,510
Disposed of by Sale | Suburban property | 310-314 Invermay Road
Real Estate Properties [Line Items]
Number of Properties | property						1
Number of Buildings						1
Square Footage (in sqft) | ft²						47,480
Disposed of by Sale | Suburban property | 253-293 George Town Road
Real Estate Properties [Line Items]
Number of Properties | property						1
Number of Buildings						1
Square Footage (in sqft) | ft²						143,914
Disposed of by Sale | Suburban property | 7 Modal Crescent
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				164,160							164,160
Disposed of by Sale | Suburban property | 71-93 Whiteside Road
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				303,488							303,488
Disposed of by Sale | Suburban property | 9-13 Titanium Court
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				69,664							69,664
Disposed of by Sale | Suburban property | 16 Rodborough Road
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				90,525							90,525
Disposed of by Sale | Suburban property | 22 Rodborough Road
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				43,427							43,427
Disposed of by Sale | Suburban property | 127-161 Cherry Lane
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				278,570							278,570
Disposed of by Sale | Suburban property | 44-46 Mandarin Street
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				226,718							226,718
Disposed of by Sale | Suburban property | 19 Leadership Way
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				76,714							76,714
Disposed of by Sale | Suburban property | Widewaters Parkway
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			8
Square Footage (in sqft) | ft²			514,241
Disposed of by Sale | Suburban property | 5062 Brittonfield Parkway
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			40,162
Disposed of by Sale | Suburban property | Woodcliff Drive
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			6
Square Footage (in sqft) | ft²			516,760
Disposed of by Sale | Suburban property | Interstate Place
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			2
Square Footage (in sqft) | ft²			61,399
Disposed of by Sale | Suburban property | 1000 Pittsford - Victor Road
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			73,358
Disposed of by Sale | Suburban property | 1200 Pittsford - Victor Road
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			18,900
Disposed of by Sale | Suburban property | Corporate Crossing
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			5
Square Footage (in sqft) | ft²			216,126
Disposed of by Sale | Suburban property | Canal View Boulevard
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			3
Square Footage (in sqft) | ft²			118,375
Disposed of by Sale | Suburban property | 14 Classic Street
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			37,084
Disposed of by Sale | Suburban property | 251 Salina Meadows Parkway
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			65,617
Disposed of by Sale | CBD
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings	2
Disposed of by Sale | CBD | Illinois Center
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			2
Square Footage (in sqft) | ft²			2,090,162
Gross Sales Price | $			$ 376,000
Gain (Loss) on Sale | $			$ 26,929
Disposed of by Sale | CBD | 16th and Race Street
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			608,625
Gross Sales Price | $			$ 43,000
Gain (Loss) on Sale | $			$ 7,922
Disposed of by Sale | CBD | 185 Asylum Street
Real Estate Properties [Line Items]
Number of Properties | property		1
Number of Buildings		1
Square Footage (in sqft) | ft²		868,395								868,395				868,395
Gross Sales Price | $		$ 113,250
Gain (Loss) on Sale | $		$ 17,619
Disposed of by Sale | CBD | 100 South Charles Street
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					159,616							159,616
Disposed of by Sale | CBD | 525 Park Street
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					75,636							75,636
Disposed of by Sale | CBD | 2501 20th Place South
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				125,722							125,722
Disposed of by Sale | CBD | 420 20th Street North
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				514,893							514,893
Disposed of by Sale | CBD | 701 Poydras Street
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				1,256,971							1,256,971
Disposed of by Sale | CBD | 300 North Greene Street
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				324,305							324,305
Disposed of by Sale | CBD | 1320 Main Street
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				334,075							334,075
Disposed of by Sale | CBD | 310-320 Pitt Street
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings				1
Square Footage (in sqft) | ft²				313,865							313,865
Disposed of by Sale | CBD | 110 W Fayette Street
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings			1
Square Footage (in sqft) | ft²			304,906
Foreclosure | CBD | 225 Water Street
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings					1
Square Footage (in sqft) | ft²					318,997							318,997
Gross Sales Price | $					$ 0
Gain (Loss) on Sale | $					$ 0

Real Estate Properties - Summ42

Real Estate Properties - Summary of Properties Sold (Footnote) (Details) $ in Thousands	1 Months Ended			3 Months Ended				9 Months Ended
	May. 31, 2015building	Mar. 31, 2015building	Jan. 31, 2013building	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)building	May. 31, 2015building	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)building	Sep. 30, 2014USD ($)
Real Estate Properties [Line Items]
Number of buildings sold			18
(Loss) gain on early extinguishment of debt | $				$ (3,887)			$ 6,699	$ 6,111	$ 6,699
Amounts reclassified from cumulative other comprehensive loss to net income | $				(1,239)				(63,825)
Foreign Currency Translation Adjustments
Real Estate Properties [Line Items]
Amounts reclassified from cumulative other comprehensive loss to net income | $				0				$ (63,207)
Disposed of by Sale
Real Estate Properties [Line Items]
Number of buildings sold								117
333 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of buildings sold						3
333 Laurel Oak Drive | Disposed of by Sale
Real Estate Properties [Line Items]
Number of buildings sold	2	1
1000 Vorhees Drive and 400 Laurel Oak Drive
Real Estate Properties [Line Items]
Number of buildings sold						3
1000 Vorhees Drive and 400 Laurel Oak Drive | Disposed of by Sale
Real Estate Properties [Line Items]
Number of buildings sold	2	1
225 Water Street in Jacksonville, Florida | Mortgage notes
Real Estate Properties [Line Items]
Principal balance | $				$ 40,100				$ 40,100
(Loss) gain on early extinguishment of debt | $								$ 17,300
Australia Portfolio | Foreign Currency Translation Adjustments
Real Estate Properties [Line Items]
Amounts reclassified from cumulative other comprehensive loss to net income | $					$ 63,200
Australia Portfolio | Disposed of by Sale
Real Estate Properties [Line Items]
Number of buildings sold					11

Real Estate Properties - Summ43

Real Estate Properties - Summary of Income Statement Information for Properties Disposed of (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Statements of Operations:
Rental income	$ 125,459	$ 174,216	$ 457,128	$ 518,663
Tenant reimbursements and other income	33,749	42,379	118,829	130,386
Total revenues	159,208	216,595	575,957	649,049
Operating expenses	73,571	99,392	261,128	293,824
General and administrative	16,249	47,450	43,718	96,395
Total expenses	130,342	204,055	478,866	576,839
Operating income	28,866	12,540	97,091	72,210
Interest and other income	637	406	4,813	1,071
Interest expense	(25,111)	(35,245)	(82,926)	(111,079)
Income from discontinued operations	$ 0	95	$ 0	8,220
Discontinued operations, properties sold
Statements of Operations:
Rental income		(16)		14,220
Tenant reimbursements and other income		407		1,730
Total revenues		391		15,950
Operating expenses		261		7,115
General and administrative		6		9
Total expenses		267		7,124
Operating income		124		8,826
Interest and other income		2		2
Interest expense		(31)		(608)
Income from discontinued operations		$ 95		$ 8,220

Investment in Direct Financin44

Investment in Direct Financing Lease - Narrative (Details) - USD ($)	Sep. 30, 2015	Dec. 31, 2014
Capital Leases, Net Investment in Direct Financing Leases [Abstract]
Percentage of term exceeding useful life of one office tower	75.00%
Carrying amount of net investment in direct financing lease	$ 6,700,000	$ 12,500,000
Allowance for losses related to our direct financing lease	$ 0	$ 0

Equity Investments - Narrative

Equity Investments - Narrative (Details) $ in Thousands	Jul. 09, 2014shares	May. 09, 2014USD ($)companyshares	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)	May. 09, 2014USD ($)company	Sep. 30, 2015USD ($)	Sep. 30, 2014USD ($)
Equity Investments
Equity in earnings (loss) of investees			$ 0	$ 1,072		$ 0	$ 24,460
Distributions of earnings from investees						$ 0	20,680
AIC
Equity Investments
Equity investments, common shares sold (in shares) | shares		20,000
Equity method investments, ownership percentage		0.00%			0.00%
Equity in earnings (loss) of investees					$ (100)
Amount invested in equity investee		$ 5,800			$ 5,800
Number of other companies which are shareholders of related party | company		5			5
Equity investments, proceeds from sale		$ 5,800
SIR
Equity Investments
Equity investments, common shares sold (in shares) | shares	22,000,000
Equity method investments, ownership percentage	0.00%
Equity in earnings (loss) of investees				$ 1,100			24,500
Distributions of earnings from investees							$ 20,700

Equity Investments - Summary of

Equity Investments - Summary of Unaudited Income Statement Information of Equity Method Investee (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Jul. 09, 2014	Sep. 30, 2015	Sep. 30, 2014	Jul. 09, 2014	Sep. 30, 2015	Sep. 30, 2014
Income Statements:
Rental income		$ 125,459	$ 174,216		$ 457,128	$ 518,663
Tenant reimbursements and other income		33,749	42,379		118,829	130,386
Total revenues		159,208	216,595		575,957	649,049
Operating expenses		73,571	99,392		261,128	293,824
General and administrative		16,249	47,450		43,718	96,395
Total expenses		130,342	204,055		478,866	576,839
Operating income		28,866	12,540		97,091	72,210
Interest expense		(25,111)	(35,245)		(82,926)	(111,079)
(Loss) gain on early extinguishment of debt		(3,887)	6,699		6,111	6,699
Income before income tax expense and equity in earnings of an investee		30,489	156,154		59,089	157,642
Income tax expense		(23)	(703)		(2,377)	(2,166)
Equity in earnings of investees		0	1,072		0	24,460
Net income		$ 30,466	$ 156,740		$ 56,712	$ 182,573
Weighted average common shares outstanding (in shares)		128,739	128,880		129,386	123,736
Net income per common share (in dollars per share)		$ 0.18	$ 1.16		$ 0.28	$ 1.14
SIR
Income Statements:
Rental income	$ 4,698			$ 98,226
Tenant reimbursements and other income	923			16,980
Total revenues	5,621			115,206
Operating expenses	1,018			20,982
Depreciation and amortization	1,043			20,832
Acquisition related costs	0			374
General and administrative	357			7,731
Total expenses	2,418			49,919
Operating income	3,203			65,287
Interest expense	(295)			(7,287)
(Loss) gain on early extinguishment of debt	0			243
Income before income tax expense and equity in earnings of an investee	2,908			58,243
Income tax expense	0			(90)
Equity in earnings of investees	11			32
Net income	$ 2,919			$ 58,185
Weighted average common shares outstanding (in shares)	59,889			52,394
Net income per common share (in dollars per share)	$ 0.05			$ 1.11

Real Estate Mortgages Receiva47

Real Estate Mortgages Receivable - Narrative (Details)	1 Months Ended
	Jan. 31, 2013USD ($)propertybuilding	Apr. 30, 2012USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Real Estate Mortgages Receivable
Total real estate mortgage receivable included in other assets, carrying value			$ 8,100,000	$ 8,100,000
Mortgage financing related to sale of suburban property	$ 7,700,000	$ 400,000
Interest rate on real estate mortgage receivable	6.00%	6.00%
Number of properties sold or agreed to be sold | property	3
Number of Buildings | building	18
Allowance for mortgage receivables			$ 0	$ 0

Indebtedness - Narrative (Detai

Indebtedness - Narrative (Details)

Aug. 03, 2015USD ($)

Jun. 05, 2015USD ($)

Jun. 03, 2015USD ($)

May. 01, 2015USD ($)

Jan. 29, 2015USD ($)option

Jan. 28, 2015USD ($)

Sep. 30, 2015USD ($)propertybuilding

Sep. 30, 2014USD ($)

Sep. 30, 2015USD ($)propertybuilding

Sep. 30, 2014USD ($)

Dec. 31, 2014USD ($)

Sep. 30, 2015USD ($)propertybuilding

Debt Instrument [Line Items]

(Loss) gain on early extinguishment of debt

$ (3,887,000)

$ 6,699,000

$ 6,111,000

$ 6,699,000

Real estate properties, net

3,088,158,000

3,088,158,000

$ 4,697,998,000

$ 3,088,158,000

Mortgage notes payable, net

367,713,000

$ 367,713,000

$ 609,249,000

367,713,000

Revolving credit facility

Debt Instrument [Line Items]

Interest rate payable percentage

1.44%

Amount outstanding

0

$ 0

0

Revolving credit facility | Minimum

Debt Instrument [Line Items]

Commitment fee percentage

0.125%

Revolving credit facility | Maximum

Debt Instrument [Line Items]

Commitment fee percentage

0.30%

Revolving credit facility | LIBOR

Debt Instrument [Line Items]

Basis points on variable rate

1.25%

Revolving credit facility | LIBOR | Minimum

Debt Instrument [Line Items]

Basis points on variable rate

0.875%

Revolving credit facility | LIBOR | Maximum

Debt Instrument [Line Items]

Basis points on variable rate

1.55%

Revolving credit facility | Base rate | Minimum

Debt Instrument [Line Items]

Basis points on variable rate

0.00%

Revolving credit facility | Base rate | Maximum

Debt Instrument [Line Items]

Basis points on variable rate

0.55%

Unsecured term loan, due December 2016

Debt Instrument [Line Items]

Basis points on variable rate

1.85%

Outstanding indebtedness

$ 400,000,000

Unsecured revolving credit facility | Revolving credit facility

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 750,000,000

$ 750,000,000

Basis points on variable rate

1.50%

Commitment fee percentage

0.35%

(Loss) gain on early extinguishment of debt

$ (400,000)

Debt instrument, number of extension options | option

2

Debt instrument, extension option term

6 months

Debt instrument, extension option fee, percent

0.075%

Amount available for borrowing

750,000,000

750,000,000

750,000,000

Unsecured revolving credit facility | Letter of credit

Debt Instrument [Line Items]

Maximum borrowing capacity

$ 100,000,000

Loan facility, 5-year term

Debt Instrument [Line Items]

Term loan amount outstanding

$ 200,000,000

200,000,000

$ 200,000,000

200,000,000

Interest accrual rate

1.59%

Loan facility, 5-year term | LIBOR

Debt Instrument [Line Items]

Basis points on variable rate

1.40%

Loan facility, 5-year term | LIBOR | Minimum

Debt Instrument [Line Items]

Basis points on variable rate

0.90%

Loan facility, 5-year term | LIBOR | Maximum

Debt Instrument [Line Items]

Basis points on variable rate

1.80%

Loan facility, 5-year term | Revolving credit facility

Debt Instrument [Line Items]

Debt instrument, term

5 years

Loan facility, 7-year term

Debt Instrument [Line Items]

Term loan amount outstanding

$ 200,000,000

$ 200,000,000

$ 200,000,000

$ 200,000,000

Interest accrual rate

1.99%

Loan facility, 7-year term | LIBOR

Debt Instrument [Line Items]

Basis points on variable rate

1.80%

Loan facility, 7-year term | LIBOR | Minimum

Debt Instrument [Line Items]

Basis points on variable rate

1.40%

Loan facility, 7-year term | LIBOR | Maximum

Debt Instrument [Line Items]

Basis points on variable rate

2.35%

Loan facility, 7-year term | Revolving credit facility

Debt Instrument [Line Items]

Debt instrument, term

7 years

Revolving credit facility and term loans

Debt Instrument [Line Items]

Additional increases in maximum amount of borrowings available

$ 1,150,000,000

5.75% unsecured senior notes due 2015

Debt Instrument [Line Items]

(Loss) gain on early extinguishment of debt

$ (100,000)

Amount of debt, redeemed, defeased, or prepaid

$ 138,800,000

Interest rate stated percentage

5.75%

Mortgage notes

Debt Instrument [Line Items]

Number of real estate properties secured by mortgage | property

6

6

6

Number of buildings secured by mortgage | building

10

10

10

Real estate properties, net

$ 452,400,000

$ 452,400,000

$ 452,400,000

Mortgage notes payable, net

367,700,000

367,700,000

367,700,000

Mortgage notes | 225 Water Street in Jacksonville, Florida

Debt Instrument [Line Items]

Outstanding indebtedness

40,100,000

40,100,000

$ 40,100,000

(Loss) gain on early extinguishment of debt

17,300,000

Interest accrual rate

10.03%

Default interest

4.00%

Mortgage notes | 1320 Main Street

Debt Instrument [Line Items]

(Loss) gain on early extinguishment of debt

(6,200,000)

Amount of debt, redeemed, defeased, or prepaid

$ 38,700,000

Mortgage notes | 111 East Wacker Drive

Debt Instrument [Line Items]

(Loss) gain on early extinguishment of debt

$ (3,900,000)

(3,900,000)

Amount of debt, redeemed, defeased, or prepaid

$ 141,400,000

7.36% Mortgage Debt | 2501 20th Place South

Debt Instrument [Line Items]

(Loss) gain on early extinguishment of debt

$ (600,000)

Amount of debt, redeemed, defeased, or prepaid

$ 10,000,000

Interest rate stated percentage

7.36%

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($)	Mar. 25, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Sep. 14, 2015	Aug. 24, 2015
Class of Stock [Line Items]
Distribution for the excess of the market value of common shares issued above carrying value of series D preferred shares redeemed		$ 0	$ 0	$ 0	$ 16,205,000
Common Shares
Class of Stock [Line Items]
Common shares issued to holders of preferred shares (in shares)				144		10,412,499
Stock repurchase program, authorized amount								$ 100,000,000
Stock repurchase program, additional authorized amount							$ 100,000,000
Number of shares repurchased (in shares)		3,410,300		3,410,300
Weighted average price per share of shares repurchased (in dollars per share)		$ 25.76		$ 25.76
Common shares from conversion of preferred shares (in shares)		2,363,103		2,363,103
Common Shares | Fundamental change conversion right
Class of Stock [Line Items]
Preferred shares converted into common shares (in shares)	10,411,779
Series D
Class of Stock [Line Items]
Preferred shares converted into common shares (in shares)				301		10,264,503
Liquidation preference (in dollars per share)	$ 25
Percentage of average closing market price of the entity's common stock based on which ratio for conversion of preferred shares into common shares is determined	98.00%
Number of consecutive trading days for calculating the average closing sale price of common shares	5 days
Common shares from conversion of preferred shares (in shares)		4,915,196		4,915,196
Series D | Fundamental change conversion right
Class of Stock [Line Items]
Preferred shares converted into common shares (in shares)	10,263,003
Distribution for the excess of the market value of common shares issued above carrying value of series D preferred shares redeemed	$ 16,200,000

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Declared Distributions (Details) - $ / shares	Oct. 09, 2015	Jul. 09, 2015	Apr. 08, 2015	Jan. 16, 2015
Series D
Class of Stock [Line Items]
Dividend declared (in dollars per share)		$ 0.40625	$ 0.40625	$ 0.40625
Series D | Subsequent event
Class of Stock [Line Items]
Dividend declared (in dollars per share)	$ 0.40625
Series E
Class of Stock [Line Items]
Dividend declared (in dollars per share)		$ 0.453125	$ 0.453125	$ 0.453125
Series E | Subsequent event
Class of Stock [Line Items]
Dividend declared (in dollars per share)	$ 0.453125

Cumulative Other Comprehensiv51

Cumulative Other Comprehensive Loss - Schedule of Amounts Recognized in Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
Amounts recognized in cumulative other comprehensive income (Loss) by component
Balance at beginning of period	$ (5,963)	$ (53,216)
Other comprehensive loss before reclassifications	(418)	(15,751)
Amounts reclassified from cumulative other comprehensive loss to net income	1,239	63,825
Net current period other comprehensive income	821	48,074
Balance at end of period	(5,142)	(5,142)
Unrealized Loss on Derivative Instruments and Other Assets
Amounts recognized in cumulative other comprehensive income (Loss) by component
Balance at beginning of period	(5,963)	(4,299)
Other comprehensive loss before reclassifications	(418)	(1,461)
Amounts reclassified from cumulative other comprehensive loss to net income	1,239	618
Net current period other comprehensive income	821	(843)
Balance at end of period	(5,142)	(5,142)
Foreign Currency Translation Adjustments
Amounts recognized in cumulative other comprehensive income (Loss) by component
Balance at beginning of period	0	(48,917)
Other comprehensive loss before reclassifications	0	(14,290)
Amounts reclassified from cumulative other comprehensive loss to net income	0	63,207
Net current period other comprehensive income	0	48,917
Balance at end of period	$ 0	$ 0

Cumulative Other Comprehensiv52

Cumulative Other Comprehensive Loss - Schedule of Reclassifications Out of Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 25,111	$ 35,245	$ 82,926	$ 111,079
Gain on sale of properties	39,793	0	42,953	0
Interest and other income	(637)	$ (406)	(4,813)	$ (1,071)
Total amounts reclassified	(1,239)		(63,825)
Foreign currency translation adjustment activity
Reclassifications out of cumulative other comprehensive income (Loss)
Total amounts reclassified	0		(63,207)
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income
Reclassifications out of cumulative other comprehensive income (Loss)
Total amounts reclassified	1,239		63,825
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Foreign currency translation adjustment activity
Reclassifications out of cumulative other comprehensive income (Loss)
Gain on sale of properties	0		63,207
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Realized gain on available for sale securities
Reclassifications out of cumulative other comprehensive income (Loss)
Interest and other income	0		(3,080)
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Interest rate swap contracts
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 1,239		$ 3,698

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Current:
State	$ 90	$ 39	$ 270	$ 300
Federal	0	0	525	0
Foreign	(67)	664	2,337	1,866
Current income tax expense (benefit)	23	703	3,132	2,166
Deferred:
Foreign	0	0	(755)	0
Deferred income tax expense (benefit)	0	0	(755)	0
Income tax expense	$ 23	$ 703	$ 2,377	$ 2,166

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details)	9 Months Ended
	Sep. 30, 2015USD ($)
Derivative [Line Items]
Aggregate termination value	$ 5,600,000
Interest rate swap
Derivative [Line Items]
Fair value of derivatives in a net liability position	5,600,000
Cash flow hedging | Designated as hedging instrument
Derivative [Line Items]
Estimated gain (loss) reclassification from OCI to income	4,500,000
Cash flow hedging | Designated as hedging instrument | Interest rate swap
Derivative [Line Items]
Amount of hedged item	$ 170,100,000
Derivative, variable interest rate	LIBOR

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Outstanding Interest Rate Derivatives Designated as Cash Flow Hedges of Interest Rate Risk (Details) - Interest rate swap - Cash flow hedging - Designated as hedging instrument $ in Thousands	Sep. 30, 2015USD ($)financial_instrument
Derivative [Line Items]
Number of Instruments | financial_instrument	2
Notional Amount	$ 170,097

Derivative Instruments - Sche56

Derivative Instruments - Schedule of Fair Value of Derivative Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Interest rate swap | Cash flow hedging | Designated as hedging instrument | Accounts payable and accrued expenses
Derivatives, Fair Value [Line Items]
Pay-fixed swaps	$ 5,142	$ 7,462

Derivative Instruments - Sche57

Derivative Instruments - Schedule of Gain or Loss Recognized on Interest Rate Derivatives Designated as Cash Flow Hedges (Details) - Cash flow hedging - Designated as hedging instrument - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Interest Rate Cash Flow Hedges [Roll Forward]
Balance at beginning of period	$ (5,963)	$ (10,079)	$ (7,462)	$ (11,706)
Amount of (loss) gain recognized in cumulative other comprehensive loss	(418)	537	(1,378)	(324)
Amount of loss reclassified from cumulative other comprehensive loss into interest expense	1,239	1,268	3,698	3,756
Unrealized gain on derivative instruments	821	1,805	2,320	3,432
Balance at end of period	$ (5,142)	$ (8,274)	$ (5,142)	$ (8,274)

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	Jun. 16, 2015USD ($)trustee$ / sharesshares	Jan. 28, 2015tranche$ / sharesshares	Mar. 25, 2014shares	Sep. 30, 2015USD ($)shares	Sep. 30, 2015USD ($)$ / sharesshares	Sep. 30, 2014USD ($)	Jul. 31, 2014trustee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of independent trustees | trustee	11						11
Officers and Employees | Employee Stock | RMR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $						$ 3.4
Officers and Employees | Employee Stock | Common Stock | RMR
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares issued (in shares)			130,914
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of independent trustees | trustee	9
Share based compensation amount | $	$ 0.1
Number of equity awards granted (in shares)	34,587	126,319
Price per share (in dollars per share) | $ / shares	$ 26.02
Vesting period	1 year	4 years
Number of shares forfeited (in shares)					8,115
Weighted average share price for forfeited shares (in dollars per share) | $ / shares					$ 26.64
Granted shares value (in dollars per share) | $ / shares		$ 26.58
Estimated future compensation expense for unvested shares | $				$ 16	$ 16
Weighted average period over which compensation expense will be recorded					3 years
Restricted shares | Independent Trustee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)	3,843
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of incentive plan after effective date					4 years
Number of equity awards granted (in shares)		256,467
Number of shares forfeited (in shares)					16,475
Weighted average share price for forfeited shares (in dollars per share) | $ / shares					$ 20.50
Granted shares value (in dollars per share) | $ / shares					$ 38.55
Estimated future compensation expense for unvested shares | $				$ 22.5	$ 22.5
Weighted average period over which compensation expense will be recorded					2 years 8 months 12 days
Number of tranches | tranche		2
Restricted stock units | Vesting on January 28, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent		50.00%
Restricted stock units | Vesting on January 28, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent		50.00%
2015 Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term of incentive plan after effective date	10 years
2015 Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for issuance (in shares)	3,250,000
Share award plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for issuance (in shares)				3,215,413	3,215,413
Share award plan | General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $				$ 3.7	$ 11.8

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Assumptions and Fair Values for Restricted Stock Units Granted in the Period (Details) - Restricted stock units	9 Months Ended
	Sep. 30, 2015$ / shares
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Fair value of RSUs granted (in dollars per share)	$ 38.55
Expected term (years)	4 years
Expected volatility	0.00%
Expected dividend yield	1.88%
Risk-free rate	0.81%

Fair Value of Assets and Liab60

Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measure at Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Recurring Fair Value Measurements:
Derivative liability		$ (6,700)
Recurring
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	$ (5,142)
Derivative liability	(5,159)
Recurring | Level 1
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	0
Derivative liability	0
Recurring | Level 2
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	(5,142)
Derivative liability	0
Recurring | Level 3
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	0
Derivative liability	$ (5,159)

Fair Value of Assets and Liab61

Fair Value of Assets and Liabilities - Narrative (Details) $ / shares in Units, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Aug. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2015USD ($)Tenant	Dec. 31, 2014USD ($)	Jul. 31, 2014USD ($)$ / shares
Fair value of assets and liabilities
Fair value of derivative liability				$ 6.7
Number of tenants responsible for more than 3% of total annualized rents | Tenant			0
Total rents | Credit concentration
Fair value of assets and liabilities
Concentration risk			4.00%
General and Administrative Expense
Fair value of assets and liabilities
Change in fair value of derivatives		$ 4.6	$ 6.9
Minimum
Fair value of assets and liabilities
Average closing price per common share during one year period after date (in dollars per share) | $ / shares					$ 26
Average closing price per common share during first and second year after date (in dollars per share) | $ / shares					$ 26
Related/Corvex
Fair value of assets and liabilities
Amount of reimbursements payable to related party if specified minimum common share price maintain during the one year period after the date on which the reimbursement is approved by shareholders					$ 8.4
Amount of reimbursements payable to related party if specified minimum common share price maintain during the one year period between the first and second anniversaries of the date on which the reimbursement is approved by shareholders					$ 8.4
Amount of reimbursements payable to related party upon the approval of shareholders	$ 8.4			$ 16.7

Fair Value of Assets and Liab62

Fair Value of Assets and Liabilities - Schedule of Valuation Techniques and Significant Unobservable Inputs Used for Level 3 Fair Value Measurements (Details) - Derivative liability - Level 3 $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)
Fair Value of Assets and Liabilities
Derivative liability	$ 5,159
Risk-free rate	0.25%
Volatility	20.00%

Fair Value of Assets and Liab63

Fair Value of Assets and Liabilities - Schedule of Fair Value and Carrying Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Carrying Amount
Fair value of financial instruments
Senior unsecured debt and mortgage notes payable, net	$ 1,828,073	$ 2,207,665
Fair Value
Fair value of financial instruments
Senior unsecured debt and mortgage notes payable, net	$ 1,885,499	$ 2,263,535

Earnings Per Common Share - Sch

Earnings Per Common Share - Schedule of Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Numerator for earnings per common share - basic:
Income from continuing operations	$ 30,466	$ 156,523	$ 56,712	$ 179,936
Preferred distributions	(6,981)	(6,981)	(20,943)	(25,114)
Excess fair value of consideration over carrying value of preferred shares	0	0	0	(16,205)
Income from continuing operations attributable to Equity Commonwealth common shareholders	23,485	149,542	35,769	138,617
Discontinued operations	0	217	0	2,637
Net income attributable to Equity Commonwealth common shareholders	23,485	149,759	35,769	141,254
Net Income (Loss) Attributable to Parent, Diluted [Abstract]
Income from continuing operations attributable to Equity Commonwealth common shareholders	23,485	149,542	35,769	138,617
Addition of Series D preferred distributions	(6,981)	(6,981)	(20,943)	(25,114)
Diluted income from continuing operations attributable to Equity Commonwealth common shareholders	23,485	151,540	35,769	138,617
Discontinued operations	0	217	0	2,637
Numerator for net income per share - diluted	$ 23,485	$ 151,757	$ 35,769	$ 141,254
Denominator for earnings per common share - basic and diluted:
Weighted average common shares outstanding — basic (in shares)	128,739	128,880	129,386	123,736
Weighted average common shares outstanding — diluted (in shares)	129,878	131,243	130,093	123,736
Earnings per share - basic:
Income from continuing operations attributable to Equity Commonwealth common shareholders (in dollars per share)	$ 0.18	$ 1.16	$ 0.28	$ 1.12
Discontinued operations (in dollars per share)	0	0	0	0.02
Net income (in dollars per share)	0.18	1.16	0.28	1.14
Earnings per share - diluted:
Income from continuing operations attributable to Equity Commonwealth common shareholders (in dollars per share)	0.18	1.16	0.27	1.12
Discontinued operations (in dollars per share)	0	0	0	0.02
Net income (in dollars per share)	$ 0.18	$ 1.16	$ 0.27	$ 1.14
Effect of Series D preferred shares; 6 1/2% cumulative convertible
Anti-dilutive securities:
Anti-dilutive securities (in shares)	2,363	0	2,363	4,786
Effect of Series D preferred shares; 6 1/2% cumulative convertible
Numerator for earnings per common share - basic:
Preferred distributions	$ 0	$ 1,998	$ 0	$ 0
Net Income (Loss) Attributable to Parent, Diluted [Abstract]
Addition of Series D preferred distributions	$ 0	$ 1,998	$ 0	$ 0

Earnings Per Common Share - S65

Earnings Per Common Share - Schedule of Computation of Basic and Diluted Earnings Per Share (Footnote) (Details) - Restricted stock units - shares	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2014
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
RSUs vested (in shares)		0
Common shares issued (in shares)	1,139,000	1,139,000	0
Weighted average common shares outstanding — diluted (in shares)	1,139,000	707,000

Segment Information - Narrative

Segment Information - Narrative (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)propertybuildingsegmentsuburban_property	Dec. 31, 2014USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	2
Real estate properties, net	$ 3,088,158	$ 4,697,998
CBD Properties
Segment Reporting Information [Line Items]
Number of real estate properties | property	24
Number of buildings | building	31
Real estate properties, net	$ 2,027,300
Suburban Properties
Segment Reporting Information [Line Items]
Number of real estate properties | suburban_property	43
Number of buildings | building	101
Real estate properties, net	$ 1,060,900
Minimum
Segment Reporting Information [Line Items]
Percentage of CBD and suburban properties that are office properties	90.00%

Segment Information - Schedule

Segment Information - Schedule of Property Level Information by Operating Segment (Details) ft² in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)ft²	Sep. 30, 2014USD ($)ft²	Sep. 30, 2015USD ($)ft²	Sep. 30, 2014USD ($)ft²
Segment Reporting Information [Line Items]
Square Footage (in sqft) | ft²	25,286	42,919	25,286	42,919
Rental income	$ 125,459	$ 174,216	$ 457,128	$ 518,663
Tenant reimbursements and other income	33,749	42,379	118,829	130,386
NOI	$ 85,637	$ 117,203	$ 314,829	$ 355,225
Operating Segments | CBD Properties
Segment Reporting Information [Line Items]
Square Footage (in sqft) | ft²	13,975	21,892	13,975	21,892
Rental income	$ 85,494	$ 109,822	$ 303,686	$ 326,155
Tenant reimbursements and other income	23,054	27,653	80,434	86,359
NOI	$ 53,564	$ 71,596	$ 203,077	$ 216,762
Operating Segments | Suburban Properties
Segment Reporting Information [Line Items]
Square Footage (in sqft) | ft²	11,311	21,027	11,311	21,027
Rental income	$ 39,965	$ 64,394	$ 153,442	$ 192,508
Tenant reimbursements and other income	10,695	14,726	38,395	44,027
NOI	$ 32,073	$ 45,607	$ 111,752	$ 138,463

Segment Information - Schedul68

Segment Information - Schedule of Reconciliation of NOI to Net Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Segment Reporting [Abstract]
Rental income	$ 125,459	$ 174,216	$ 457,128	$ 518,663
Tenant reimbursements and other income	33,749	42,379	118,829	130,386
Operating expenses	(73,571)	(99,392)	(261,128)	(293,824)
NOI	85,637	117,203	314,829	355,225
Depreciation and amortization	(40,522)	(57,213)	(156,858)	(168,693)
General and administrative	(16,249)	(47,450)	(43,718)	(96,395)
Loss on asset impairment	0	0	(17,162)	(17,922)
Acquisition related costs	0	0	0	(5)
Operating income	28,866	12,540	97,091	72,210
Interest and other income	637	406	4,813	1,071
Interest expense	(25,111)	(35,245)	(82,926)	(111,079)
(Loss) gain on early extinguishment of debt	(3,887)	6,699	6,111	6,699
Gain on sale of equity investment	0	171,754	0	171,721
Gain on issuance of shares by an equity investee	0	0	0	17,020
Foreign currency exchange loss	(9,809)	0	(8,953)	0
Gain on sale of properties	39,793	0	42,953	0
Income from continuing operations before income taxes and equity in earnings of investees	30,489	156,154	59,089	157,642
Income tax expense	(23)	(703)	(2,377)	(2,166)
Equity in earnings of investees	0	1,072	0	24,460
Income from continuing operations	30,466	156,523	56,712	179,936
Income from discontinued operations	0	95	0	8,220
Gain (loss) on asset impairment from discontinued operations	0	122	0	(2,238)
Loss on early extinguishment of debt from discontinued operations	0	0	0	(3,345)
Net income	$ 30,466	$ 156,740	$ 56,712	$ 182,573

Related Person Transactions - N

Related Person Transactions - Narrative (Details)

Nov. 02, 2015USD ($)

Jul. 20, 2015USD ($)option

May. 04, 2015USD ($)

Mar. 01, 2015USD ($)

Sep. 29, 2014trusteeagreement

Jul. 31, 2014USD ($)option$ / shares

Jul. 09, 2014USD ($)$ / sharesshares

Jun. 01, 2014USD ($)optionparking_space

May. 09, 2014USD ($)companyshares

Feb. 29, 2012

Aug. 31, 2015USD ($)

Feb. 28, 2015USD ($)

Jun. 30, 2014USD ($)shares

Dec. 31, 2014USD ($)

May. 31, 2014USD ($)

May. 08, 2014

SIR

Related Party Transaction [Line Items]

Ownership percentage prior to transaction

100.00%

Less than wholly owned subsidiary, common shares owned (in shares) | shares

22,000,000

Equity method investments, ownership percentage

0.00%

36.70%

Equity investments, common shares sold (in shares) | shares

22,000,000

Price per common share (in dollars per share) | $ / shares

$ 32.04

Equity investments, proceeds from sale

$ 704,800,000

Amended Agreement

Related Party Transaction [Line Items]

Base business management fee payable percentage

10.00%

Minimum

Related Party Transaction [Line Items]

Average closing price per common share during one year period after date (in dollars per share) | $ / shares

$ 26

Average closing price per common share during first and second year after date (in dollars per share) | $ / shares

$ 26

Equity Group Investments and associated entities

Related Party Transaction [Line Items]

Lease term

5 years

7 months

1 year

Number of renewal options of lease arrangement | option

1

1

1

Renewal term of lease arrangement

5 years

3 months

3 months

Lease payment, initial term

$ 500,000

$ 200,000

$ 200,000

Lease payment

$ 800,000

$ 200,000

Term of license agreement

1 year

License fee

$ 100,000

$ 200,000

Number of parking spaces | parking_space

1

Equity Group Investments and associated entities | Subsequent event

Related Party Transaction [Line Items]

Lease payment

$ 100,000

License fee

$ 100,000

Related/Corvex

Related Party Transaction [Line Items]

Due to related persons

33,500,000

Amount of reimbursements payable to related party upon the approval of shareholders

$ 8,400,000

$ 16,700,000

Amount of reimbursements payable to related party if specified minimum common share price maintain during the one year period after the date on which the reimbursement is approved by shareholders

8,400,000

Amount of reimbursements payable to related party if specified minimum common share price maintain during the one year period between the first and second anniversaries of the date on which the reimbursement is approved by shareholders

$ 8,400,000

RMR

Related Party Transaction [Line Items]

Number of primary agreements | agreement

3

Number of managing trustees | trustee

1

Business management fees

$ 31,700,000

Portion of shares issued in payment of management fee (in shares) | shares

68,206

Property management and construction supervision fees

$ 13,800,000

Legal fees and costs

5,400,000

RMR Australia

Related Party Transaction [Line Items]

Business and property management fees

$ 900,000

RMR and RMR Australia

Related Party Transaction [Line Items]

Monthly management transition fee

$ 100,000

$ 1,200,000

AIC

Related Party Transaction [Line Items]

Equity method investments, ownership percentage

12.50%

Equity investments, common shares sold (in shares) | shares

20,000

Equity investments, proceeds from sale

$ 5,800,000

Amount invested in equity investee

$ 5,200,000

Number of other companies which are shareholders of related party | company

5

Coverage amount for property insurance

$ 500,000,000

Subsequent Events - Narrative (

Subsequent Events - Narrative (Details) $ in Millions	1 Months Ended		9 Months Ended
	Oct. 31, 2015USD ($)ft²propertybuilding	Jan. 31, 2013propertybuilding	Sep. 30, 2015ft²propertybuilding	Sep. 30, 2014ft²
Subsequent Event [Line Items]
Number of properties sold or agreed to be sold | property		3
Number of buildings sold		18
Property square feet | ft²			25,286,000	42,919,000
Disposed of by Sale
Subsequent Event [Line Items]
Number of properties sold or agreed to be sold | property			82
Number of buildings sold			117
Property square feet | ft²			16,368,645
Subsequent event | Disposed of by Sale
Subsequent Event [Line Items]
Number of properties sold or agreed to be sold | property	7
Number of buildings sold	13
Property square feet | ft²	1,263,809
Gross proceeds from sale of real estate anticipated | $	$ 131.2