Equity Commonwealth (EQC) 10-Q 29 Jul 16 2016 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2016	Jul. 25, 2016
Document and Entity Information
Entity Registrant Name	Equity Commonwealth
Entity Central Index Key	803,649
Document Type	10-Q
Document Period End Date	Jun. 30, 2016
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		125,533,376
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q2

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Real estate properties:
Land	$ 328,351	$ 389,410
Buildings and improvements	3,074,591	3,497,942
Total real estate properties, at cost, gross	3,402,942	3,887,352
Accumulated depreciation	(828,786)	(898,939)
Total real estate properties, at cost, net	2,574,156	2,988,413
Properties held for sale	150,766	0
Acquired real estate leases, net	70,724	88,760
Cash and cash equivalents	1,772,337	1,802,729
Restricted cash	33,777	32,245
Rents receivable, net of allowance for doubtful accounts of $4,431 and $7,715, respectively	169,800	174,676
Other assets, net	140,215	144,341
Total assets	4,911,775	5,231,164
LIABILITIES AND SHAREHOLDERS’ EQUITY
Senior unsecured debt, net	1,312,707	1,450,606
Mortgage notes payable, net	244,850	246,510
Liabilities related to properties held for sale	1,687	0
Accounts payable and accrued expenses	117,363	123,587
Assumed real estate lease obligations, net	2,761	4,296
Rent collected in advance	24,615	27,340
Security deposits	9,154	10,338
Total liabilities	1,713,137	1,862,677
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; 125,533,376 and 126,349,914 shares issued and outstanding, respectively	1,255	1,263
Additional paid in capital	4,398,033	4,414,611
Cumulative net income	2,467,955	2,333,709
Cumulative other comprehensive loss	(2,234)	(3,687)
Cumulative common distributions	(3,111,868)	(3,111,868)
Cumulative preferred distributions	(673,766)	(650,195)
Total shareholders’ equity	3,198,638	3,368,487
Total liabilities and shareholders’ equity	4,911,775	5,231,164
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 shares issued and outstanding, aggregate liquidation preference of $122,880	119,263	119,263
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; 0 and 11,000,000 shares issued and outstanding, respectively, aggregate liquidation preference $0 and $275,000, respectively	$ 0	$ 265,391

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Rents receivable, allowance for doubtful accounts	$ 4,431	$ 4,431	$ 7,715
Common shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common shares of beneficial interest, shares authorized (in shares)	350,000,000	350,000,000	350,000,000
Common shares of beneficial interest, shares issued (in shares)	125,533,376	125,533,376	126,349,914
Common shares of beneficial interest, shares outstanding (in shares)	125,533,376	125,533,376	126,349,914
Series D
Preferred shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred shares of beneficial interest, shares authorized (in shares)	50,000,000	50,000,000	50,000,000
Preferred shares, dividend yield	6.50%	6.50%	6.50%
Preferred shares of beneficial interest, shares issued (in shares)	4,915,196	4,915,196	4,915,196
Preferred shares, of beneficial interest, shares outstanding (in shares)	4,915,196	4,915,196	4,915,196
Preferred shares, aggregate liquidation preference	$ 122,880	$ 122,880	$ 122,880
Series E
Preferred shares of beneficial interest, par value (in dollars per share)	$ 0	$ 0	$ 0.01
Preferred shares of beneficial interest, shares authorized (in shares)	0	0	50,000,000
Preferred shares, dividend yield		0.00%	7.25%
Preferred shares of beneficial interest, shares issued (in shares)	0	0	11,000,000
Preferred shares, of beneficial interest, shares outstanding (in shares)	0	0	11,000,000
Preferred shares, aggregate liquidation preference	$ 0	$ 0	$ 275,000

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenues:
Rental income	$ 121,735	$ 163,697	$ 231,623	$ 331,669
Tenant reimbursements and other income	23,632	39,997	50,879	85,080
Total revenues	145,367	203,694	282,502	416,749
Expenses:
Operating expenses	51,393	89,686	108,651	187,557
Depreciation and amortization	37,331	53,637	73,582	116,336
General and administrative	12,177	10,911	25,489	27,469
Loss on asset impairment	43,736	15,258	43,736	17,162
Total expenses	144,637	169,492	251,458	348,524
Operating income	730	34,202	31,044	68,225
Interest and other income	2,204	728	4,171	4,176
Interest expense (including net amortization of debt discounts, premiums and deferred financing fees of $949, $(177), $1,932 and $(148), respectively)	(21,300)	(27,973)	(43,647)	(57,815)
Gain (loss) on early extinguishment of debt	0	10,426	(118)	9,998
Foreign currency exchange gain (loss)	0	856	(5)	856
Gain (loss) on sale of properties	106,375	(2,708)	143,041	3,160
Income before income taxes	88,009	15,531	134,486	28,600
Income tax expense	(165)	(2,915)	(240)	(2,354)
Net income	87,844	12,616	134,246	26,246
Preferred distributions	(6,981)	(6,981)	(13,962)	(13,962)
Excess fair value of consideration paid over carrying value of preferred shares	(9,609)	0	(9,609)	0
Net income attributable to Equity Commonwealth common shareholders	$ 71,254	$ 5,635	$ 110,675	$ 12,284
Weighted average common shares outstanding — basic (in shares)	125,508	129,733	125,674	129,714
Weighted average common shares outstanding — diluted (in shares)	126,937	130,537	127,229	130,205
Earnings per common share attributable to Equity Commonwealth common shareholders:
Basic (in USD per share)	$ 0.57	$ 0.04	$ 0.88	$ 0.09
Diluted (in USD per share)	$ 0.56	$ 0.04	$ 0.87	$ 0.09

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Income Statement [Abstract]
Amortization of debt discounts, premiums and deferred financing fees	$ 949	$ (177)	$ 1,932	$ (148)

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 87,844	$ 12,616	$ 134,246	$ 26,246
Other comprehensive income (loss), net of tax:
Unrealized gain (loss) on derivative instruments and other assets	780	958	1,453	(1,664)
Foreign currency translation adjustments	0	65,307	0	48,917
Total comprehensive income	$ 88,624	$ 78,881	$ 135,699	$ 73,499

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 134,246	$ 26,246
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	55,799	86,374
Net amortization of debt discounts, premiums and deferred financing fees	1,932	(148)
Straight line rental income	(9,430)	(1,611)
Amortization of acquired real estate leases	14,834	20,413
Other amortization	7,937	12,782
Share-based compensation	8,977	8,110
Loss on asset impairment	43,736	17,162
Loss (gain) on early extinguishment of debt	118	(9,998)
Foreign currency exchange loss (gain)	5	(856)
Net gain on sale of properties	(143,041)	(3,160)
Change in assets and liabilities:
Restricted cash	(4,115)	(2,917)
Rents receivable and other assets	(13,727)	(20,429)
Accounts payable and accrued expenses	(1,970)	(847)
Rent collected in advance	(1,651)	(8,539)
Security deposits	224	597
Cash provided by operating activities	93,874	123,179
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate improvements	(60,289)	(28,623)
Principal payments received from direct financing lease	0	3,789
Proceeds from sale of properties, net	388,774	962,003
Proceeds from sale of securities	0	27,068
Decrease (increase) in restricted cash	2,583	(2,313)
Cash provided by investing activities	331,068	961,924
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase and retirement of common shares	(25,563)	0
Redemption of preferred shares	(275,000)	0
Payments on borrowings	(140,749)	(141,908)
Deferred financing fees	(52)	(7,143)
Distributions to preferred shareholders	(13,962)	(13,962)
Cash used in financing activities	(455,326)	(163,013)
Effect of exchange rate changes on cash	(8)	296
(Decrease) increase in cash and cash equivalents	(30,392)	922,386
Cash and cash equivalents at beginning of period	1,802,729	364,516
Cash and cash equivalents at end of period	1,772,337	1,286,902
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	45,021	62,094
Taxes paid	103	3,088
NON-CASH INVESTING ACTIVITIES:
Increase in capital expenditures recorded as liabilities	$ 728	$ 523

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2016
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, 2015. 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	6 Months Ended
	Jun. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which requires more timely recognition of credit losses associated with financial assets. This update is effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2018. 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 March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This update is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods, but early adoption is permitted. We are currently in the process of evaluating the impact the adoption of this ASU will have on our condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets. The ASU also requires lessees or lessors to capitalize only initial direct costs of leases. This update is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, but early adoption is permitted. We are currently in the process of evaluating the impact the adoption of this ASU will have on our condensed consolidated financial statements. 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 adopted this standard on January 1, 2016 and made the following reclassifications to the prior years' consolidated balance sheet to conform to the current year's presentation (in thousands): Balance Sheet as of December 31, 2015 Originally Reported Effect of Change As Adjusted Other assets, net 157,549 (13,208 ) 144,341 Senior unsecured debt, net 1,460,592 (9,986 ) 1,450,606 Mortgage notes payable, net 249,732 (3,222 ) 246,510 In April 2014, the FASB issued 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 2016 dispositions, 2015 dispositions and properties held for sale as of June 30, 2016 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 2016 and 2015 dispositions and properties held for sale have not been presented as discontinued operations in the statements of operations.

Real Estate Properties

Real Estate Properties	6 Months Ended
	Jun. 30, 2016
Real Estate [Abstract]
Real Estate Properties	Real Estate Properties During the six months ended June 30, 2016 and 2015 , we made improvements, excluding tenant-funded improvements, to our properties totaling $59.2 million and $ 27.8 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, 2015, we had no properties classified as held for sale. As of June 30, 2016 , we classified the following properties as held for sale (dollars in thousands): Asset Date Sold Number of Number of Square Footage Gross Sales Price Property 111 River Street July 2016 1 1 566,215 $ 235,000 Portfolio of properties 128 Crews Drive July 2016 1 1 185,600 111 Southchase Boulevard July 2016 1 1 168,087 1043 Global Avenue July 2016 1 1 450,000 South Carolina industrial portfolio 3 3 803,687 $ 30,000 4 4 1,369,902 $ 265,000 Summarized balance sheet information for all properties classified as held for sale is as follows (in thousands): June 30, 2016 Real estate properties $ 136,299 Acquired real estate leases 1,751 Other assets, net 12,716 Properties held for sale $ 150,766 Accounts payable and accrued expenses $ 674 Assumed real estate lease obligations 403 Rent collected in advance 266 Security deposits 344 Liabilities related to properties held for sale $ 1,687 Property Dispositions: During the six months ended June 30, 2016 , we sold the following properties (dollars in thousands): Asset Date Sold Number of Number of Square Footage Gross Sales Price Gain on Sale Properties Executive Park February 2016 1 9 427,443 $ 50,865 $ 16,532 3330 N Washington Boulevard March 2016 1 1 55,719 11,250 5,457 111 East Kilbourn Avenue March 2016 1 1 373,669 60,500 14,677 1525 Locust Street April 2016 1 1 98,009 17,700 8,956 633 Ahua Street April 2016 1 1 93,141 29,000 15,963 Lakewood on the Park May 2016 1 2 180,558 37,100 13,616 Leased Land June 2016 1 7 — 48,450 15,914 9110 East Nichols Avenue June 2016 1 1 143,958 17,200 642 Portfolios of properties 812 San Antonio Street May 2016 1 1 59,321 1601 Rio Grande Street May 2016 1 1 56,219 Downtown Austin portfolio 2 2 115,540 $ 32,600 $ 20,584 785 Schilinger Road South June 2016 1 1 72,000 401 Vine Street June 2016 1 1 53,980 633 Frazier Drive June 2016 1 1 150,000 9840 Gateway Boulevard North June 2016 1 1 72,000 3003 South Expressway 281 June 2016 1 1 150,000 1331 North Center Parkway June 2016 1 1 53,980 Movie theater portfolio 6 6 551,960 $ 109,100 $ 30,595 16 31 2,039,997 $ 413,765 $ 142,936 During the year ended December 31, 2015, we disposed of 91 properties ( 135 buildings) and one land parcel with a combined 18.9 million square feet for an aggregate gross sales price of $2.0 billion , excluding closing costs.

Real Estate Mortgages Receivabl

Real Estate Mortgages Receivable	6 Months Ended
	Jun. 30, 2016
Mortgage Loans on Real Estate [Abstract]
Real Estate Mortgages Receivable	Real Estate Mortgages Receivable As of June 30, 2016 and December 31, 2015 , 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 June 30, 2016 , and December 31, 2015 .

Indebtedness

Indebtedness	6 Months Ended
	Jun. 30, 2016
Debt Disclosure [Abstract]
Indebtedness	Indebtedness Unsecured Revolving Credit Facility and Term Loan: We are party to a credit agreement pursuant to which the lenders agreed to provide a $750.0 million unsecured revolving credit facility, a $200.0 million 5 -year term loan facility, and a $200.0 million 7 -year term loan facility. 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. 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 June 30, 2016 . As of June 30, 2016 , the interest rate payable on borrowings under our revolving credit facility was 1.72% . As of June 30, 2016 , we had no balance outstanding and $750.0 million available under our revolving credit facility and the facility fee as of June 30, 2016 was 0.25% . 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 June 30, 2016 . As of June 30, 2016 , the interest rates for the amounts outstanding under our 5-year term loan and 7-year term loan were 1.87% and 2.27% , respectively. As of June 30, 2016 , 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 and our credit 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 June 30, 2016 , we believe we were in compliance with all of our respective covenants under our public debt indenture and related supplements and our credit agreement. Senior Unsecured Notes: On February 16, 2016, we redeemed at par $139.1 million of our 6.25% senior unsecured notes due 2016 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 for the six months ended June 30, 2016 . Mortgage Notes Payable: At June 30, 2016 , five of our properties ( 8 buildings) with an aggregate net book value of $291.6 million had secured mortgage notes totaling $244.9 million (including net premiums and discounts and unamortized deferred financing fees) maturing from 2017 through 2026.

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2016
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Common Share Issuances: See Note 10 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. On March 17, 2016, our Board of Trustees authorized the repurchase of up to an additional $150.0 million of our outstanding common shares over the twelve month period following the date of authorization. During the six months ended June 30, 2016 , we purchased and retired 983,789 of our common shares at a weighted average price of $25.94 per share, for a total of $25.5 million . Since the inception of the common share repurchase plan through June 30, 2016, we have purchased and retired a total of 4,394,089 of our common shares at a weighted average price of $25.80 per share, for a total of $113.4 million . We have $236.6 million remaining available under our share repurchase program as of June 30, 2016 , of which $86.6 million is scheduled to expire in September 2016. Preferred Share Redemption: On May 15, 2016, we redeemed all of our 11,000,000 outstanding series E preferred shares at a price of $25.00 per share, for a total of $275.0 million , plus any accrued and unpaid dividends. The redemption payment occurred on May 16, 2016 (the first business day following the redemption date). We recorded $9.6 million related to the excess fair value of consideration paid over the carrying value of the preferred shares as a reduction to net income attributable to common shareholders for the three and six months ended June 30, 2016 . Preferred Share Distributions: In 2016, 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 26, 2016 February 5, 2016 February 16, 2016 $ 0.40625 $ 0.453125 April 15, 2016 April 25, 2016 May 16, 2016 $ 0.40625 $ 0.453125

Cumulative Other Comprehensive

Cumulative Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2016
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 for the three and six months ended June 30, 2016 (in thousands): Unrealized Loss on Derivative Instruments Balance as of April 1, 2016 $ (3,014 ) Other comprehensive loss before reclassifications (326 ) Amounts reclassified from cumulative other comprehensive loss to net income 1,106 Net current period other comprehensive income 780 Balance as of June 30, 2016 $ (2,234 ) Unrealized Loss on Derivative Instruments Balance as of January 1, 2016 $ (3,687 ) Other comprehensive loss before reclassifications (771 ) Amounts reclassified from cumulative other comprehensive loss to net income 2,224 Net current period other comprehensive income 1,453 Balance as of June 30, 2016 $ (2,234 ) The following table presents reclassifications out of cumulative other comprehensive loss for the three and six months ended June 30, 2016 (in thousands): Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income Details about Cumulative Other Comprehensive Loss Components Three Months Ended June 30, 2016 Six Months Ended June 30, 2016 Affected Line Items in the Statement of Operations Interest rate swap contracts $ 1,106 $ 2,224 Interest expense

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2016
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. We are also subject to certain state and local taxes without regard to our REIT status. In prior periods, we were subject to Australian taxes. Our provision for income taxes consists of the following (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Current: State $ 165 $ 90 $ 240 $ 180 Federal — 525 — 525 Foreign — 2,450 — 2,404 165 3,065 240 3,109 Deferred: Foreign — (150 ) — (755 ) — (150 ) — (755 ) Income tax expense $ 165 $ 2,915 $ 240 $ 2,354

Derivative Instruments

Derivative Instruments	6 Months Ended
	Jun. 30, 2016
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 interest rates. The only risk we currently manage by using derivative instruments is related to 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 2016, 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 $1.8 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 $168.6 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. On March 4, 2016, we purchased an interest rate cap with a LIBOR strike price of 2.50% . The interest rate cap, effective April 1, 2016, has a notional amount of $400.0 million and a maturity date of March 1, 2019. As of June 30, 2016 , 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 $ 168,616 Interest rate cap 1 $ 400,000 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 June 30, 2016 and December 31, 2015 (amounts in thousands): Fair Value as of Interest Rate Derivative Designated as Hedging Instrument Balance Sheet Location June 30, December 31, Pay-fixed swaps Accounts payable and accrued expenses $ (1,828 ) $ (3,687 ) Interest rate cap Other assets $ 117 $ — 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 six months ended June 30, 2016 and 2015 (amounts in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Balance at beginning of period $ (3,014 ) $ (6,921 ) $ (3,687 ) $ (7,462 ) Amount of loss recognized in cumulative other comprehensive loss (326 ) (274 ) (771 ) (960 ) Amount of loss reclassified from cumulative other comprehensive loss into interest expense 1,106 1,232 2,224 2,459 Unrealized gain on derivative instruments 780 958 1,453 1,499 Balance at end of period $ (2,234 ) $ (5,963 ) $ (2,234 ) $ (5,963 ) Credit-risk-related Contingent Features Our agreements with each of our derivative counterparties contain a provision providing that if we default or are capable of being declared in default on any of our indebtedness, we could also be declared in default on our derivative obligations. As of June 30, 2016 , 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 $2.2 million . As of June 30, 2016 , 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 $2.2 million at June 30, 2016 .

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation Equity Commonwealth 2015 Omnibus Incentive Plan On January 26, 2016, the Board of Trustees approved an amendment to the 2015 Omnibus Incentive Plan (as amended, the 2015 Incentive Plan) to allow the Compensation Committee (Committee) to authorize in an award agreement a transfer of all or a part of certain equity awards not for value to a “family member” (as defined in the 2015 Incentive Plan). 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. To the extent that an award does not vest, the dividends will be forfeited. 2016 Equity Award Activity On June 16, 2016, 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 2016-2017 year of service on the Board of Trustees. These awards equated to 3,463 shares per Trustee, for a total of 31,167 shares, valued at $28.88 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. On January 26, 2016, the Committee approved a grant of 136,623 restricted common shares and 277,386 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 2015. The restricted shares are service based awards and vest over a four -year period. The restricted shares were granted on January 26, 2016 and were valued at $26.93 per share, the closing price of our common shares on the New York Stock Exchange (NYSE) on that day. 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 26, 2016 - January 26, 2019. Following the end of the performance period on January 26, 2019, the number of earned awards will be determined. The earned awards vest in two tranches with 50% of the earned award vesting on January 26, 2019 and the remaining 50% of the earned award vesting on January 26, 2020, subject to the grant recipient’s continued employment. 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. During the three and six months ended June 30, 2016, due to employee terminations, 539 restricted shares were forfeited with an average price per share value at grant date of $26.82 , and 1,094 RSUs were forfeited with an average per share fair value at grant date of $38.72 . 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 vested one year after the date of the award. 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. 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. 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. Outstanding Equity Awards As of June 30, 2016 , the estimated future compensation expense for all unvested restricted share grants was $15.8 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 2.5 years. As of June 30, 2016 , the estimated future compensation expense for all unvested RSUs was $25.3 million . The weighted average period over which the future compensation expense will be recorded for the RSUs is approximately 2.4 years. The assumptions and fair values for the RSUs granted for the six months ended June 30, 2016 are included in the following table on a per share basis. 2016 Fair value of RSUs granted $ 38.80 Expected term (years) 4 Expected volatility — Expected dividend yield 1.86 % Risk-free rate 1.07 % During the three months ended June 30, 2016 and 2015, we recorded $4.6 million and $4.1 million , respectively, and during the six months ended June 30, 2016 and 2015, we recorded $9.0 million and $8.1 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 June 30, 2016 , 2,358,464 common shares remain available for issuance under the Plan.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	6 Months Ended
	Jun. 30, 2016
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 2016 , categorized by the level of inputs used in the valuation of each asset and liability (dollars in thousands): Fair Value at June 30, 2016 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 $ (1,828 ) $ — $ (1,828 ) $ — Effective portion of interest rate cap contract 117 — 117 — Derivative liability (8,375 ) — — (8,375 ) Effective Portion of Interest Rate Swap and Cap Contracts The fair value of our interest rate swap and cap 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 June 30, 2016 , 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 Fund Management, LLC and Corvex Management LP (Related/Corvex) (see Note 14 for additional information). 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 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 as a result, in August 2015 we paid $8.4 million to Related/Corvex. The potential future reimbursement of $8.4 million for the second one year period 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 June 30, 2016 and December 31, 2015 was $8.4 million and $7.2 million , respectively. We recognized expense of $42,000 and $1.2 million for the three and six months ended June 30, 2016 , respectively, which was recorded in general and administrative expenses in our condensed consolidated statement of operations for such periods. The valuation techniques and significant unobservable inputs used for our level 3 fair value measurement at June 30, 2016 were as follows: Description Fair Value at June 30, 2016 Primary Valuation Technique Unobservable Inputs Rate Derivative liability $ 8,375 Monte Carlo simulation Risk-free rate 0.20% Volatility 20.0% Properties Held and Used As part of our disposition plan, and pursuant to our accounting policy, in 2016, we evaluated the recoverability of the carrying values of each of the real estate assets that comprised our portfolio and determined that due to the shortening of the expected periods of ownership as a result of the disposition plan and current estimates of market value, it was necessary to reduce the net book value of a portion of the real estate assets in our portfolio to their estimated fair values. We anticipate the potential disposition of certain properties prior to the end of their remaining useful lives. As a result, we recorded an impairment charge related to 111 Monument Circle, 101-115 W. Washington Street and 100 East Wisconsin Avenue of $43.7 million for the three and six months ended June 30, 2016 in accordance with our impairment analysis procedures. We determined these impairments based on third party offer prices and independent third party broker information, which are level 2 inputs according to the fair value hierarchy established in ASC 820. We reduced the aggregate carrying value of these properties from $308.6 million to their estimated fair value of $264.9 million . We evaluated each of our properties and determined there were no additional valuation adjustments necessary at June 30, 2016. 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 June 30, 2016 and December 31, 2015, the fair value of these additional financial instruments were not materially different from their carrying values, except as follows (in thousands): June 30, 2016 December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value Senior unsecured debt and mortgage notes payable, net $ 1,557,557 $ 1,623,934 $ 1,697,116 $ 1,749,211 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 June 30, 2016 , no single tenant of ours is responsible for more than 4.5% of our total annualized rents. Our derivative financial instruments, including interest rate swaps and cap, 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	6 Months Ended
	Jun. 30, 2016
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 June 30, Six Months Ended June 30, 2016 2015 2016 2015 Numerator for earnings per common share - basic and diluted: Net income $ 87,844 $ 12,616 $ 134,246 $ 26,246 Preferred distributions (6,981 ) (6,981 ) (13,962 ) (13,962 ) Excess fair value of consideration paid over carrying value of preferred shares (9,609 ) — (9,609 ) — Numerator for net income per share $ 71,254 $ 5,635 $ 110,675 $ 12,284 Denominator for earnings per common share - basic and diluted: Weighted average number of common shares outstanding - basic 125,508 129,733 125,674 129,714 Weighted average number of common shares outstanding - diluted (1) 126,937 130,537 127,229 130,205 Net income per common share attributable to Equity Commonwealth common shareholders: Basic $ 0.57 $ 0.04 $ 0.88 $ 0.09 Diluted $ 0.56 $ 0.04 $ 0.87 $ 0.09 Anti-dilutive securities: Effect of Series D preferred shares; 6 1/2% cumulative convertible (2) 2,363 2,363 2,363 2,363 (1) As of June 30, 2016 , 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 June 30, 2016 , and 2015 , 1,429 and 803 common shares would be issued to the RSU holders, respectively. Using a weighted average basis, 1,429 and 804 common shares are reflected in diluted earnings per share for the three months ended June 30, 2016 and 2015 , respectively and 1,555 and 491 common shares are reflected in diluted earnings per share for the six months ended June 30, 2016 and 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	6 Months Ended
	Jun. 30, 2016
Segment Reporting [Abstract]
Segment Information	Segment Information Our primary business is the ownership and operation of office properties, and we currently have one reportable segment. Due to significant dispositions during 2015, during the fourth quarter of 2015, we changed the composition of our operating segments from two reportable segments (central business district properties and suburban properties) to one reportable segment. This change was made based on the financial information reviewed and used by the chief operating decision maker to make operating decisions, assess performance, develop strategy and allocate capital resources. More than 90% of our revenues are from office properties.

Related Person Transactions

Related Person Transactions	6 Months Ended
	Jun. 30, 2016
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions The following discussion includes a description of our related person transactions for the six months ended June 30, 2016 and 2015 . Certain of these related person transactions, and their approvals, occurred prior to the election of our new Board of Trustees at the special meeting of shareholders held on May 23, 2014 (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 (20th/21st Floor Office Lease). 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 to $0.9 million annually thereafter. This lease was approved by the Audit Committee of the Board of Trustees on June 16, 2015. We recently completed improvements to the office space utilizing the $0.7 million tenant improvement allowance provided for by the lease. In connection with the 20th/21st Floor Office Lease, effective February 1, 2016, we entered into a lease with Two North Riverside Plaza Joint Venture Limited Partnership, an entity associated with Mr. Zell, our Chairman, for storage space in the basement of Two North Riverside Plaza, in Chicago, Illinois. The lease expires December 31, 2020, however each party has the right to terminate on 30 days' prior written notice, and the payment is nominal. This lease was approved by the Audit Committee of the Board of Trustees. 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 included 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 . The extension of the license agreement was terminated as of December 30, 2015. 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 was 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 . The extension of the sublease agreement was terminated as of December 30, 2015. 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 as a result, in August 2015 we paid $8.4 million to Related/Corvex. Transactions with Prior Related Persons: Termination and Cooperation Agreement: On September 30, 2014, we entered into a termination and cooperation agreement (Cooperation Agreement) with Reit Management & Research LLC (RMR) and RMR Australia Asset Management Pty Ltd (together, Former 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, Former Manager agreed to use best efforts to assist us in the transition of our management and operations. We paid Former 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 Former 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 Former Manager.

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2016
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In July 2016, in a series of transactions, we sold four properties ( four buildings), with 1,369,902 square feet for $265.0 million , excluding closing costs. These properties were classified as held for sale as of June 30, 2016 (see Note 3). In July 2016, we sold Sky Park Centre ( two buildings), with 63,485 square feet for $13.7 million , excluding closing costs and Raintree Industrial Park ( 12 buildings), with 563,182 square feet for $11.5 million , excluding closing costs.

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2016
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, 2015. 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	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments, which requires more timely recognition of credit losses associated with financial assets. This update is effective for fiscal years beginning after December 15, 2019, and for interim periods within those fiscal years. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2018. 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 March 2016, the FASB issued ASU 2016-09, Compensation-Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, which simplifies several aspects of the accounting for employee share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This update is effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods, but early adoption is permitted. We are currently in the process of evaluating the impact the adoption of this ASU will have on our condensed consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases, which amends the existing accounting standards for lease accounting, including requiring lessees to recognize most leases on their balance sheets. The ASU also requires lessees or lessors to capitalize only initial direct costs of leases. This update is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years, but early adoption is permitted. We are currently in the process of evaluating the impact the adoption of this ASU will have on our condensed consolidated financial statements. 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 adopted this standard on January 1, 2016 and made the following reclassifications to the prior years' consolidated balance sheet to conform to the current year's presentation (in thousands): Balance Sheet as of December 31, 2015 Originally Reported Effect of Change As Adjusted Other assets, net 157,549 (13,208 ) 144,341 Senior unsecured debt, net 1,460,592 (9,986 ) 1,450,606 Mortgage notes payable, net 249,732 (3,222 ) 246,510 In April 2014, the FASB issued 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 2016 dispositions, 2015 dispositions and properties held for sale as of June 30, 2016 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 2016 and 2015 dispositions and properties held for sale have not been presented as discontinued operations in the statements of operations.

Recent Accounting Pronounceme24

Recent Accounting Pronouncements (Tables)	6 Months Ended
	Jun. 30, 2016
New Accounting Pronouncements and Changes in Accounting Principles [Abstract]
New Accounting Pronouncement	We adopted this standard on January 1, 2016 and made the following reclassifications to the prior years' consolidated balance sheet to conform to the current year's presentation (in thousands): Balance Sheet as of December 31, 2015 Originally Reported Effect of Change As Adjusted Other assets, net 157,549 (13,208 ) 144,341 Senior unsecured debt, net 1,460,592 (9,986 ) 1,450,606 Mortgage notes payable, net 249,732 (3,222 ) 246,510

Real Estate Properties (Tables)

Real Estate Properties (Tables)	6 Months Ended
	Jun. 30, 2016
Real Estate [Abstract]
Summary of Properties Held for Sale and Balance Sheet Information for all Properties Classified as Held for sale	As of June 30, 2016 , we classified the following properties as held for sale (dollars in thousands): Asset Date Sold Number of Number of Square Footage Gross Sales Price Property 111 River Street July 2016 1 1 566,215 $ 235,000 Portfolio of properties 128 Crews Drive July 2016 1 1 185,600 111 Southchase Boulevard July 2016 1 1 168,087 1043 Global Avenue July 2016 1 1 450,000 South Carolina industrial portfolio 3 3 803,687 $ 30,000 4 4 1,369,902 $ 265,000 Summarized balance sheet information for all properties classified as held for sale is as follows (in thousands): June 30, 2016 Real estate properties $ 136,299 Acquired real estate leases 1,751 Other assets, net 12,716 Properties held for sale $ 150,766 Accounts payable and accrued expenses $ 674 Assumed real estate lease obligations 403 Rent collected in advance 266 Security deposits 344 Liabilities related to properties held for sale $ 1,687
Summary of Properties Sold and Income Statement Information for Properties Disposed of	During the six months ended June 30, 2016 , we sold the following properties (dollars in thousands): Asset Date Sold Number of Number of Square Footage Gross Sales Price Gain on Sale Properties Executive Park February 2016 1 9 427,443 $ 50,865 $ 16,532 3330 N Washington Boulevard March 2016 1 1 55,719 11,250 5,457 111 East Kilbourn Avenue March 2016 1 1 373,669 60,500 14,677 1525 Locust Street April 2016 1 1 98,009 17,700 8,956 633 Ahua Street April 2016 1 1 93,141 29,000 15,963 Lakewood on the Park May 2016 1 2 180,558 37,100 13,616 Leased Land June 2016 1 7 — 48,450 15,914 9110 East Nichols Avenue June 2016 1 1 143,958 17,200 642 Portfolios of properties 812 San Antonio Street May 2016 1 1 59,321 1601 Rio Grande Street May 2016 1 1 56,219 Downtown Austin portfolio 2 2 115,540 $ 32,600 $ 20,584 785 Schilinger Road South June 2016 1 1 72,000 401 Vine Street June 2016 1 1 53,980 633 Frazier Drive June 2016 1 1 150,000 9840 Gateway Boulevard North June 2016 1 1 72,000 3003 South Expressway 281 June 2016 1 1 150,000 1331 North Center Parkway June 2016 1 1 53,980 Movie theater portfolio 6 6 551,960 $ 109,100 $ 30,595 16 31 2,039,997 $ 413,765 $ 142,936

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2016
Stockholders' Equity Note [Abstract]
Schedule of Declared Distributions	In 2016, 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 26, 2016 February 5, 2016 February 16, 2016 $ 0.40625 $ 0.453125 April 15, 2016 April 25, 2016 May 16, 2016 $ 0.40625 $ 0.453125

Cumulative Other Comprehensiv27

Cumulative Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2016
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 for the three and six months ended June 30, 2016 (in thousands): Unrealized Loss on Derivative Instruments Balance as of April 1, 2016 $ (3,014 ) Other comprehensive loss before reclassifications (326 ) Amounts reclassified from cumulative other comprehensive loss to net income 1,106 Net current period other comprehensive income 780 Balance as of June 30, 2016 $ (2,234 ) Unrealized Loss on Derivative Instruments Balance as of January 1, 2016 $ (3,687 ) Other comprehensive loss before reclassifications (771 ) Amounts reclassified from cumulative other comprehensive loss to net income 2,224 Net current period other comprehensive income 1,453 Balance as of June 30, 2016 $ (2,234 )
Schedule of Reclassifications Out of Cumulative Other Comprehensive Loss	The following table presents reclassifications out of cumulative other comprehensive loss for the three and six months ended June 30, 2016 (in thousands): Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income Details about Cumulative Other Comprehensive Loss Components Three Months Ended June 30, 2016 Six Months Ended June 30, 2016 Affected Line Items in the Statement of Operations Interest rate swap contracts $ 1,106 $ 2,224 Interest expense

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2016
Income Tax Disclosure [Abstract]
Schedule of Provision for Income Taxes	Our provision for income taxes consists of the following (in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Current: State $ 165 $ 90 $ 240 $ 180 Federal — 525 — 525 Foreign — 2,450 — 2,404 165 3,065 240 3,109 Deferred: Foreign — (150 ) — (755 ) — (150 ) — (755 ) Income tax expense $ 165 $ 2,915 $ 240 $ 2,354

Derivative Instruments (Tables)

Derivative Instruments (Tables)	6 Months Ended
	Jun. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Outstanding Interest Rate Derivatives Designated as Cash Flow Hedges of Interest Rate Risk	As of June 30, 2016 , 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 $ 168,616 Interest rate cap 1 $ 400,000
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 June 30, 2016 and December 31, 2015 (amounts in thousands): Fair Value as of Interest Rate Derivative Designated as Hedging Instrument Balance Sheet Location June 30, December 31, Pay-fixed swaps Accounts payable and accrued expenses $ (1,828 ) $ (3,687 ) Interest rate cap Other assets $ 117 $ —
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 six months ended June 30, 2016 and 2015 (amounts in thousands): Three Months Ended June 30, Six Months Ended June 30, 2016 2015 2016 2015 Balance at beginning of period $ (3,014 ) $ (6,921 ) $ (3,687 ) $ (7,462 ) Amount of loss recognized in cumulative other comprehensive loss (326 ) (274 ) (771 ) (960 ) Amount of loss reclassified from cumulative other comprehensive loss into interest expense 1,106 1,232 2,224 2,459 Unrealized gain on derivative instruments 780 958 1,453 1,499 Balance at end of period $ (2,234 ) $ (5,963 ) $ (2,234 ) $ (5,963 )

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2016
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 six months ended June 30, 2016 are included in the following table on a per share basis. 2016 Fair value of RSUs granted $ 38.80 Expected term (years) 4 Expected volatility — Expected dividend yield 1.86 % Risk-free rate 1.07 %

Fair Value of Assets and Liab31

Fair Value of Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2016
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 2016 , categorized by the level of inputs used in the valuation of each asset and liability (dollars in thousands): Fair Value at June 30, 2016 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 $ (1,828 ) $ — $ (1,828 ) $ — Effective portion of interest rate cap contract 117 — 117 — Derivative liability (8,375 ) — — (8,375 )
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 June 30, 2016 were as follows: Description Fair Value at June 30, 2016 Primary Valuation Technique Unobservable Inputs Rate Derivative liability $ 8,375 Monte Carlo simulation Risk-free rate 0.20% Volatility 20.0%
Schedule of Fair Value and Carrying Value of Financial Instruments	At June 30, 2016 and December 31, 2015, the fair value of these additional financial instruments were not materially different from their carrying values, except as follows (in thousands): June 30, 2016 December 31, 2015 Carrying Amount Fair Value Carrying Amount Fair Value Senior unsecured debt and mortgage notes payable, net $ 1,557,557 $ 1,623,934 $ 1,697,116 $ 1,749,211

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2016
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 June 30, Six Months Ended June 30, 2016 2015 2016 2015 Numerator for earnings per common share - basic and diluted: Net income $ 87,844 $ 12,616 $ 134,246 $ 26,246 Preferred distributions (6,981 ) (6,981 ) (13,962 ) (13,962 ) Excess fair value of consideration paid over carrying value of preferred shares (9,609 ) — (9,609 ) — Numerator for net income per share $ 71,254 $ 5,635 $ 110,675 $ 12,284 Denominator for earnings per common share - basic and diluted: Weighted average number of common shares outstanding - basic 125,508 129,733 125,674 129,714 Weighted average number of common shares outstanding - diluted (1) 126,937 130,537 127,229 130,205 Net income per common share attributable to Equity Commonwealth common shareholders: Basic $ 0.57 $ 0.04 $ 0.88 $ 0.09 Diluted $ 0.56 $ 0.04 $ 0.87 $ 0.09 Anti-dilutive securities: Effect of Series D preferred shares; 6 1/2% cumulative convertible (2) 2,363 2,363 2,363 2,363 (1) As of June 30, 2016 , 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 June 30, 2016 , and 2015 , 1,429 and 803 common shares would be issued to the RSU holders, respectively. Using a weighted average basis, 1,429 and 804 common shares are reflected in diluted earnings per share for the three months ended June 30, 2016 and 2015 , respectively and 1,555 and 491 common shares are reflected in diluted earnings per share for the six months ended June 30, 2016 and 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.

Recent Accounting Pronounceme33

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets, net	$ 140,215	$ 144,341
Senior unsecured debt, net	1,312,707	1,450,606
Mortgage notes payable, net	$ 244,850	246,510
ASU 2015-03
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets, net		144,341
Senior unsecured debt, net		1,450,606
Mortgage notes payable, net		246,510
ASU 2015-03 | Originally Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets, net		157,549
Senior unsecured debt, net		1,460,592
Mortgage notes payable, net		249,732
ASU 2015-03 | Effect of Change
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other assets, net		(13,208)
Senior unsecured debt, net		(9,986)
Mortgage notes payable, net		$ (3,222)

Real Estate Properties - Narrat

Real Estate Properties - Narrative (Details) $ in Thousands	1 Months Ended	6 Months Ended		12 Months Ended
	Jan. 31, 2013building	Jun. 30, 2016USD ($)ft²building	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)ft²land_parcelbuildingproperty
Real Estate Properties [Line Items]
Real estate improvements | $		$ 59,200	$ 27,800
Number of properties held for sale | property				0
Number of buildings sold | building	18
Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties sold | property				91
Number of buildings sold | building		31		135
Number of land parcels | land_parcel				1
Square Footage (in sqft) | ft²		2,039,997		18,900,000
Gross sales price | $		$ 413,765		$ 2,000,000

Real Estate Properties - Summar

Real Estate Properties - Summary of Properties Held for Sale (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016USD ($)ft²buildingproperty	Dec. 31, 2015property
Real Estate Properties [Line Items]
Number of Properties		0
Held-for-sale
Real Estate Properties [Line Items]
Number of Properties	4
Number of Buildings | building	4
Square Footage (in sqft) | ft²	1,369,902
Gross Sales Price | $	$ 265,000
Held-for-sale | 111 River Street
Real Estate Properties [Line Items]
Number of Properties	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	566,215
Gross Sales Price | $	$ 235,000
Held-for-sale | 128 Crews Drive
Real Estate Properties [Line Items]
Number of Properties	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	185,600
Held-for-sale | 111 Southchase Boulevard
Real Estate Properties [Line Items]
Number of Properties	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	168,087
Held-for-sale | 1043 Global Avenue
Real Estate Properties [Line Items]
Number of Properties	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	450,000
Held-for-sale | South Carolina industrial portfolio
Real Estate Properties [Line Items]
Number of Properties	3
Number of Buildings | building	3
Square Footage (in sqft) | ft²	803,687
Gross Sales Price | $	$ 30,000

Real Estate Properties - Summ36

Real Estate Properties - Summary of Balance Sheet Information for all Properties Classified as Held for sale (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities related to properties held for sale	$ 1,687	$ 0
Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Real estate properties	136,299
Acquired real estate leases	1,751
Other assets, net	12,716
Properties held for sale	150,766
Accounts payable and accrued expenses	674
Assumed real estate lease obligations	403
Rent collected in advance	266
Security deposits	344
Liabilities related to properties held for sale	$ 1,687

Real Estate Properties - Summ37

Real Estate Properties - Summary of Properties Sold (Details) $ in Thousands	1 Months Ended						3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2016USD ($)ft²buildingproperty	May 31, 2016USD ($)ft²buildingproperty	Apr. 30, 2016USD ($)ft²buildingproperty	Mar. 31, 2016USD ($)ft²buildingproperty	Feb. 29, 2016USD ($)ft²buildingproperty	Jan. 31, 2013buildingproperty	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)ft²buildingproperty	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)ft²building
Real Estate Properties [Line Items]
Number of Properties | property						3
Number of Buildings | building						18
Gain on Sale							$ 106,375	$ (2,708)	$ 143,041	$ 3,160
Disposed of by Sale
Real Estate Properties [Line Items]
Number of Properties | property									16
Number of Buildings | building									31		135
Square Footage (in sqft) | ft²									2,039,997		18,900,000
Gross Sales Price									$ 413,765		$ 2,000,000
Gain on Sale									$ 142,936
Disposed of by Sale | Executive Park
Real Estate Properties [Line Items]
Number of Properties | property					1
Number of Buildings | building					9
Square Footage (in sqft) | ft²					427,443
Gross Sales Price					$ 50,865
Gain on Sale					$ 16,532
Disposed of by Sale | 3330 N Washington Boulevard
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings | building				1
Square Footage (in sqft) | ft²				55,719
Gross Sales Price				$ 11,250
Gain on Sale				$ 5,457
Disposed of by Sale | 111 East Kilbourn Avenue
Real Estate Properties [Line Items]
Number of Properties | property				1
Number of Buildings | building				1
Square Footage (in sqft) | ft²				373,669
Gross Sales Price				$ 60,500
Gain on Sale				$ 14,677
Disposed of by Sale | 1525 Locust Street
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings | building			1
Square Footage (in sqft) | ft²			98,009
Gross Sales Price			$ 17,700
Gain on Sale			$ 8,956
Disposed of by Sale | 633 Ahua Street
Real Estate Properties [Line Items]
Number of Properties | property			1
Number of Buildings | building			1
Square Footage (in sqft) | ft²			93,141
Gross Sales Price			$ 29,000
Gain on Sale			$ 15,963
Disposed of by Sale | Lakewood on the Park
Real Estate Properties [Line Items]
Number of Properties | property		1
Number of Buildings | building		2
Square Footage (in sqft) | ft²		180,558
Gross Sales Price		$ 37,100
Gain on Sale		$ 13,616
Disposed of by Sale | Leased Land
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	7
Square Footage (in sqft) | ft²	0
Gross Sales Price	$ 48,450
Gain on Sale	$ 15,914
Disposed of by Sale | 9110 East Nichols Avenue
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	143,958
Gross Sales Price	$ 17,200
Gain on Sale	$ 642
Disposed of by Sale | 812 San Antonio Street
Real Estate Properties [Line Items]
Number of Properties | property		1
Number of Buildings | building		1
Square Footage (in sqft) | ft²		59,321
Disposed of by Sale | 1601 Rio Grande Street
Real Estate Properties [Line Items]
Number of Properties | property		1
Number of Buildings | building		1
Square Footage (in sqft) | ft²		56,219
Disposed of by Sale | Downtown Austin portfolio
Real Estate Properties [Line Items]
Number of Properties | property		2
Number of Buildings | building		2
Square Footage (in sqft) | ft²		115,540
Gross Sales Price		$ 32,600
Gain on Sale		$ 20,584
Disposed of by Sale | 785 Schilinger Road South
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	72,000
Disposed of by Sale | 401 Vine Street
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	53,980
Disposed of by Sale | 633 Frazier Drive
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	150,000
Disposed of by Sale | 9840 Gateway Boulevard North
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	72,000
Disposed of by Sale | 3003 South Expressway 281
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	150,000
Disposed of by Sale | 1331 North Center Parkway
Real Estate Properties [Line Items]
Number of Properties | property	1
Number of Buildings | building	1
Square Footage (in sqft) | ft²	53,980
Disposed of by Sale | Movie theater portfolio
Real Estate Properties [Line Items]
Number of Properties | property	6
Number of Buildings | building	6
Square Footage (in sqft) | ft²	551,960
Gross Sales Price	$ 109,100
Gain on Sale	$ 30,595

Real Estate Mortgages Receiva38

Real Estate Mortgages Receivable - Narrative (Details)	1 Months Ended
	Jan. 31, 2013USD ($)buildingproperty	Apr. 30, 2012USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2015USD ($)
Mortgage Loans on Real Estate [Abstract]
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, percent	6.00%	6.00%
Number of properties sold or agreed to be sold | property	3
Number of buildings sold | building	18
Allowance for mortgage receivables			$ 0	$ 0

Indebtedness - Narrative (Detai

Indebtedness - Narrative (Details)	Jun. 30, 2016USD ($)buildingproperty	Feb. 16, 2016USD ($)	Jun. 30, 2016USD ($)buildingproperty	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)optionbuildingproperty	Jun. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Loss on early extinguishment of debt			$ 0	$ (10,426,000)	$ 118,000	$ (9,998,000)
Real estate properties, net	$ 2,574,156,000		2,574,156,000		2,574,156,000		$ 2,988,413,000
Mortgage notes payable, net	244,850,000		244,850,000		$ 244,850,000		$ 246,510,000
Revolving credit facility
Debt Instrument [Line Items]
Interest rate payable percentage					1.72%
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 spread on variable rate					1.25%
Revolving credit facility | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate					0.875%
Revolving credit facility | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate					1.55%
Revolving credit facility | Base rate | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate					0.00%
Revolving credit facility | Base rate | Maximum
Debt Instrument [Line Items]
Basis spread on variable rate					0.55%
Unsecured revolving credit facility | Revolving credit facility
Debt Instrument [Line Items]
Maximum borrowing capacity	750,000,000		750,000,000		$ 750,000,000
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
Commitment fee percentage	0.25%
Unsecured revolving credit facility | Letter of credit
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 100,000,000		100,000,000		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
Interest accrual rate					1.87%
Loan facility, 5-year term | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate					1.40%
Loan facility, 5-year term | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate					0.90%
Loan facility, 5-year term | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread 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
Interest accrual rate					2.27%
Loan facility, 7-year term | LIBOR
Debt Instrument [Line Items]
Basis spread on variable rate					1.80%
Loan facility, 7-year term | LIBOR | Minimum
Debt Instrument [Line Items]
Basis spread on variable rate					1.40%
Loan facility, 7-year term | LIBOR | Maximum
Debt Instrument [Line Items]
Basis spread 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		$ 1,150,000,000		$ 1,150,000,000
Senior Notes Five Point Seven Five Percent Due 2015
Debt Instrument [Line Items]
Amount of debt, redeemed, defeased, or prepaid		$ 139,100,000
Interest rate stated percentage		6.25%
Loss on early extinguishment of debt					$ 100,000
Mortgage notes
Debt Instrument [Line Items]
Number of real estate properties secured by mortgage | property	5		5		5
Number of buildings secured by mortgage | building	8		8		8
Real estate properties, net	$ 291,600,000		$ 291,600,000		$ 291,600,000
Mortgage notes payable, net	$ 244,900,000		$ 244,900,000		$ 244,900,000

Shareholders' Equity - Narrativ

Shareholders' Equity - Narrative (Details) - USD ($)	May 15, 2016	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Mar. 17, 2016	Sep. 14, 2015	Aug. 24, 2015
Class of Stock [Line Items]
Excess fair value of consideration paid over carrying value of preferred shares		$ 9,609,000	$ 0	$ 9,609,000	$ 0
Common Shares
Class of Stock [Line Items]
Stock repurchase program, authorized amount									$ 100,000,000
Stock repurchase program, additional authorized amount							$ 150,000,000	$ 100,000,000
Number of shares repurchased (in shares)				983,789		4,394,089
Treasury stock acquired, average cost per share (in USD per share)				$ 25.94		$ 25.80
Stock repurchased and retired during period, value				$ 25,500,000		$ 113,400,000
Remaining authorized repurchase amount		236,600,000		236,600,000		236,600,000
Remaining authorized repurchase amount, subject to expiration		$ 86,600,000		$ 86,600,000		$ 86,600,000
Series E
Class of Stock [Line Items]
Stock repurchased during period, shares	11,000,000
Redemption price per share (in USD per share)	$ 25
Preferred stock, redemption amount	$ 275,000,000

Shareholders' Equity - Schedule

Shareholders' Equity - Schedule of Declared Distributions (Details) - $ / shares	May 16, 2016	Apr. 15, 2016	Feb. 16, 2016	Jan. 26, 2016
Series D
Class of Stock [Line Items]
Dividend declared (in USD per share)		$ 0.40625		$ 0.40625
Dividends paid (in USD per share)	$ 0.40625		$ 0.40625
Series E
Class of Stock [Line Items]
Dividend declared (in USD per share)		$ 0.453125		$ 0.453125
Dividends paid (in USD per share)	$ 0.453125		$ 0.453125

Cumulative Other Comprehensiv42

Cumulative Other Comprehensive Loss - Schedule of Amounts Recognized in Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2016
Amounts recognized in cumulative other comprehensive income (Loss) by component
Beginning of Period		$ (3,687)
Balance as of June 30, 2016	$ (2,234)	(2,234)
Unrealized Loss on Derivative Instruments
Amounts recognized in cumulative other comprehensive income (Loss) by component
Beginning of Period	(3,014)	(3,687)
Other comprehensive loss before reclassifications	(326)	(771)
Amounts reclassified from cumulative other comprehensive loss to net income	1,106	2,224
Net current period other comprehensive income	780	1,453
Balance as of June 30, 2016	$ (2,234)	$ (2,234)

Cumulative Other Comprehensiv43

Cumulative Other Comprehensive Loss - Schedule of Reclassifications Out of Cumulative Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 21,300	$ 27,973	$ 43,647	$ 57,815
Amounts Reclassified from Cumulative Other Comprehensive Loss to Net Income | Interest rate swap contracts
Reclassifications out of cumulative other comprehensive income (Loss)
Interest expense	$ 1,106		$ 2,224

Income Taxes - Schedule of Prov

Income Taxes - Schedule of Provision for Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Current:
State	$ 165	$ 90	$ 240	$ 180
Federal	0	525	0	525
Foreign	0	2,450	0	2,404
Current income tax expense (benefit)	165	3,065	240	3,109
Deferred:
Foreign	0	(150)	0	(755)
Deferred income tax expense (benefit)	0	(150)	0	(755)
Income tax expense	$ 165	$ 2,915	$ 240	$ 2,354

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Mar. 04, 2016
Derivative [Line Items]
Aggregate termination value	$ 2,200
Interest rate swap
Derivative [Line Items]
Fair value of derivatives in a net liability position	2,200
Cash flow hedging | Designated as hedging instrument
Derivative [Line Items]
Estimated gain (loss) reclassification from OCI to income	1,800
Cash flow hedging | Designated as hedging instrument | Interest rate swap
Derivative [Line Items]
Amount of hedged item	$ 168,600
Derivative, variable interest rate, percent	LIBOR
Notional Amount (in thousands)	$ 168,616
Cash flow hedging | Designated as hedging instrument | Interest rate cap
Derivative [Line Items]
Notional Amount (in thousands)	$ 400,000
LIBOR | Interest rate cap
Derivative [Line Items]
Derivative, cap interest rate, percent		2.50%

Derivative Instruments - Schedu

Derivative Instruments - Schedule of Outstanding Interest Rate Derivatives Designated as Cash Flow Hedges of Interest Rate Risk (Details) - Cash flow hedging - Designated as hedging instrument $ in Thousands	Jun. 30, 2016USD ($)financial_instrument
Interest rate swap
Derivative [Line Items]
Number of Instruments | financial_instrument	2
Notional Amount (in thousands) | $	$ 168,616
Interest rate cap
Derivative [Line Items]
Number of Instruments | financial_instrument	1
Notional Amount (in thousands) | $	$ 400,000

Derivative Instruments - Sche47

Derivative Instruments - Schedule of Fair Value of Derivative Financial Instruments (Details) - Cash flow hedging - Designated as hedging instrument - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Interest rate swap | Accounts payable and accrued expenses
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Designated as Hedging Instrument	$ (1,828)	$ (3,687)
Interest rate cap | Other Assets
Derivatives, Fair Value [Line Items]
Interest Rate Derivative Designated as Hedging Instrument	$ 117	$ 0

Derivative Instruments - Sche48

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		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Derivative
Balance at beginning of period	$ (3,014)	$ (6,921)	$ (3,687)	$ (7,462)
Amount of loss recognized in cumulative other comprehensive loss	(326)	(274)	(771)	(960)
Amount of loss reclassified from cumulative other comprehensive loss into interest expense	1,106	1,232	2,224	2,459
Unrealized gain on derivative instruments	780	958	1,453	1,499
Balance at end of period	$ (2,234)	$ (5,963)	$ (2,234)	$ (5,963)

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions	Jun. 16, 2016USD ($)trustee$ / sharesshares	Jan. 26, 2016$ / sharesshares	Jun. 16, 2015USD ($)trustee$ / sharesshares	Jan. 28, 2015$ / sharesshares	Jun. 30, 2016USD ($)$ / sharesshares	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)tranche$ / sharesshares	Jun. 30, 2015USD ($)
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)		136,623		126,319
Vesting period					4 years
Granted shares value (in dollars per share) | $ / shares		$ 26.93		$ 26.58
Shares forfeited in period					539		539
Weighted average grant date fair value | $ / shares					$ 26.82		$ 26.82
Estimated future compensation expense for unvested shares | $					$ 15.8		$ 15.8
Weighted average period over which compensation expense will be recorded							2 years 6 months
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equity awards granted (in shares)		277,386		256,467
Granted shares value (in dollars per share) | $ / shares							$ 38.80
Number of tranches | tranche							2
Shares forfeited in period					1,094		1,094
Weighted average grant date fair value | $ / shares					$ 38.72		$ 38.72
Estimated future compensation expense for unvested shares | $					$ 25.3		$ 25.3
Weighted average period over which compensation expense will be recorded							2 years 4 months 24 days
Restricted stock units | Vesting in three years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent							50.00%
Restricted stock units | Vesting in four years
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting percent							50.00%
Share award plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common shares available for issuance (in shares)					2,358,464		2,358,464
Share award plan | General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense | $					$ 4.6	$ 4.1	$ 9	$ 8.1
Independent Trustee | Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of trustees to whom common shares granted | trustee	9		9
Stock issued during period, value, share-based compensation, gross | $	$ 0.1		$ 0.1
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Per Employee	3,463		3,843
Number of equity awards granted (in shares)	31,167		34,587
Vesting period	1 year		1 year
Granted shares value (in dollars per share) | $ / shares	$ 28.88		$ 26.02

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	6 Months Ended
	Jun. 30, 2016$ / 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)	$ 38.80
Expected term (years)	4 years
Expected volatility	0.00%
Expected dividend yield	1.86%
Risk-free rate	1.07%

Fair Value of Assets and Liab51

Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measure at Fair Value (Details) - Recurring $ in Thousands	Jun. 30, 2016USD ($)
Recurring Fair Value Measurements:
Derivative liability	$ (8,375)
Level 1
Recurring Fair Value Measurements:
Derivative liability	0
Level 2
Recurring Fair Value Measurements:
Derivative liability	0
Level 3
Recurring Fair Value Measurements:
Derivative liability	(8,375)
Interest rate swap
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	(1,828)
Interest rate swap | Level 1
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	0
Interest rate swap | Level 2
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	(1,828)
Interest rate swap | Level 3
Recurring Fair Value Measurements:
Effective portion of interest rate swap contracts	0
Interest rate cap
Recurring Fair Value Measurements:
Effective portion of interest rate cap contract	117
Interest rate cap | Level 1
Recurring Fair Value Measurements:
Effective portion of interest rate cap contract	0
Interest rate cap | Level 2
Recurring Fair Value Measurements:
Effective portion of interest rate cap contract	117
Interest rate cap | Level 3
Recurring Fair Value Measurements:
Effective portion of interest rate cap contract	$ 0

Fair Value of Assets and Liab52

Fair Value of Assets and Liabilities - Narrative (Details)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Aug. 31, 2015USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2015USD ($)	Jun. 30, 2016USD ($)Tenant	Jun. 30, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2015USD ($)	Jul. 31, 2014USD ($)$ / shares
Fair value of assets and liabilities
Loss on asset impairment		$ 43,736,000	$ 15,258,000	$ 43,736,000	$ 17,162,000
Number of tenants responsible for more than 4% of total annualized rents | Tenant				0
Real estate properties, net		2,574,156,000		$ 2,574,156,000			$ 2,988,413,000
Total rents | Credit concentration
Fair value of assets and liabilities
Concentration risk, percent				4.50%
General and Administrative Expense
Fair value of assets and liabilities
Change in fair value of derivatives		42,000		$ 1,200,000
Derivative liability | Level 3
Fair value of assets and liabilities
Derivative liability		8,375,000		8,375,000			$ 7,200,000
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 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
Derivative liability, potential reimbursement to related party contingent on stock price		8,400,000		8,400,000
Carrying Amount | Disposition Plan | Fair Value, Measurements, Nonrecurring
Fair value of assets and liabilities
Real estate properties, net		308,600,000		308,600,000
Market Approach Valuation Technique | Real Estate Held-for-sale | Level 2
Fair value of assets and liabilities
Assets, fair value disclosure		$ 264,900,000		$ 264,900,000

Fair Value of Assets and Liab53

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 - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair Value of Assets and Liabilities
Derivative liability	$ 8,375	$ 7,200
Risk-free rate	0.20%
Volatility	20.00%

Fair Value of Assets and Liab54

Fair Value of Assets and Liabilities - Schedule of Fair Value and Carrying Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Carrying Amount
Fair value of financial instruments
Senior unsecured debt and mortgage notes payable, net	$ 1,557,557	$ 1,697,116
Fair Value
Fair value of financial instruments
Senior unsecured debt and mortgage notes payable, net	$ 1,623,934	$ 1,749,211

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		6 Months Ended		12 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Numerator for earnings per common share - basic and diluted:
Net income	$ 87,844	$ 12,616	$ 134,246	$ 26,246
Preferred distributions	(6,981)	(6,981)	(13,962)	(13,962)
Excess fair value of consideration paid over carrying value of preferred shares	(9,609)	0	(9,609)	0
Net income attributable to Equity Commonwealth common shareholders	$ 71,254	$ 5,635	$ 110,675	$ 12,284
Denominator for earnings per common share - basic and diluted:
Weighted average number of common shares outstanding — basic (in shares)	125,508	129,733	125,674	129,714
Weighted average number of common shares outstanding — diluted (in shares)	126,937	130,537	127,229	130,205
Net income per common share attributable to Equity Commonwealth common shareholders:
Basic (in USD per share)	$ 0.57	$ 0.04	$ 0.88	$ 0.09
Diluted (in USD per share)	$ 0.56	$ 0.04	$ 0.87	$ 0.09
Effect of Series D preferred shares; 6 1/2% cumulative convertible
Anti-dilutive securities:
Effect of Series D preferred shares; 6 1/2% cumulative convertible (in shares)	2,363	2,363	2,363	2,363
Effect of Series D preferred shares; 6 1/2% cumulative convertible
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Preferred shares, dividend yield	6.50%	6.50%	6.50%	6.50%	6.50%

Earnings Per Common Share - S56

Earnings Per Common Share - Schedule of Computation of Basic and Diluted Earnings Per Share (Footnote) (Details) - Restricted stock units - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
RSUs vested (in shares)			0
Common shares issued (in shares)	1,429,000	803,000	1,429,000	803,000
Weighted average common shares outstanding — diluted (in shares)	1,429,000	804,000	1,555,000	491,000

Segment Information - Narrative

Segment Information - Narrative (Details) - segment	6 Months Ended	9 Months Ended
	Jun. 30, 2016	Sep. 30, 2015
Segment Reporting [Abstract]
Number of reportable segments	1	2
Percentage of revenue from office properties (more than)	90.00%

Related Person Transactions - N

Related Person Transactions - Narrative (Details) $ / shares in Units, $ in Millions	Nov. 02, 2015USD ($)	Jul. 20, 2015option	May 04, 2015USD ($)	Mar. 01, 2015USD ($)	Jul. 31, 2014USD ($)option$ / shares	Jun. 01, 2014USD ($)parking_space	Aug. 31, 2015USD ($)	Feb. 28, 2015USD ($)	Jun. 30, 2016USD ($)	Dec. 31, 2014USD ($)
Related Party Transaction [Line Items]
Lease termination period duration									30 days
Minimum
Related Party Transaction [Line Items]
Average closing price per common share during one year period after date (at least) (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
Number of renewal options of lease arrangement | option		1			1
Renewal term of lease arrangement		5 years			3 months
Annual lease payment, year one									$ 0.5
Tenant Improvements									0.7
Term of license agreement						1 year
License fee	$ 0.1		$ 0.1			$ 0.2
Number of parking spaces | parking_space						1
Lease payment, initial term					$ 0.2
Lease payment	$ 0.1		$ 0.2
Equity Group Investments and associated entities | Minimum
Related Party Transaction [Line Items]
Annual lease payment after year one									0.8
Equity Group Investments and associated entities | Maximum
Related Party Transaction [Line Items]
Annual lease payment after year one									$ 0.9
Related/Corvex
Related Party Transaction [Line Items]
Due to related persons					33.5
Amount of reimbursements payable to related party upon the approval of shareholders							$ 8.4			$ 16.7
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
RMR and RMR Australia
Related Party Transaction [Line Items]
Monthly management transition fee				$ 0.1				$ 1.2

Subsequent Events - Narrative (

Subsequent Events - Narrative (Details) $ in Thousands	1 Months Ended		6 Months Ended	12 Months Ended
	Jul. 31, 2016USD ($)ft²buildingproperty	Jan. 31, 2013building	Jun. 30, 2016USD ($)ft²building	Dec. 31, 2015USD ($)ft²buildingproperty
Subsequent Event [Line Items]
Number of buildings sold		18
Disposed of by Sale
Subsequent Event [Line Items]
Number of properties sold | property				91
Number of buildings sold			31	135
Property square feet | ft²			2,039,997	18,900,000
Gross sales price | $			$ 413,765	$ 2,000,000
Subsequent event | Disposed of by Sale
Subsequent Event [Line Items]
Number of properties sold | property	4
Number of buildings sold	4
Property square feet | ft²	1,369,902
Gross sales price | $	$ 265,000
Sky Park Centre San Diego CA | Subsequent event | Disposed of by Sale
Subsequent Event [Line Items]
Number of buildings sold	2
Property square feet | ft²	63,485
Gross sales price | $	$ 13,700
Raintree Industrial Park | Subsequent event | Disposed of by Sale
Subsequent Event [Line Items]
Number of buildings sold	12
Property square feet | ft²	563,182
Gross sales price | $	$ 11,500