Office Properties Income Trust (OPI) 10-Q 2 Aug 18 2018 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Jul. 31, 2018
Document and Entity Information
Entity Registrant Name	Government Properties Income Trust
Entity Central Index Key	1,456,772
Document Type	10-Q
Document Period End Date	Jun. 30, 2018
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		99,165,854
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Real estate properties:
Land	$ 587,173	$ 627,108
Buildings and improvements	2,258,276	2,348,613
Total real estate properties, gross	2,845,449	2,975,721
Accumulated depreciation	(358,286)	(341,848)
Total real estate properties, net	2,487,163	2,633,873
Equity investment in Select Income REIT	456,756	467,499
Investment in unconsolidated joint ventures	46,712	50,202
Acquired real estate leases, net	297,696	351,872
Cash and cash equivalents	18,695	16,569
Restricted cash	2,448	3,111
Rents receivable, net	61,522	61,429
Deferred leasing costs, net	22,900	22,977
Other assets, net	113,877	96,033
Total assets	3,507,769	3,703,565
LIABILITIES AND SHAREHOLDERS’ EQUITY
Unsecured revolving credit facility	452,000	570,000
Unsecured term loans, net	548,192	547,852
Senior unsecured notes, net	945,346	944,140
Mortgage notes payable, net	180,986	183,100
Accounts payable and other liabilities	80,728	89,440
Due to related persons	7,129	4,859
Assumed real estate lease obligations, net	11,738	13,635
Total liabilities	2,226,119	2,353,026
Commitments and contingencies
Preferred units of limited partnership	0	20,496
Shareholders’ equity:
Common shares of beneficial interest, $.01 par value: 150,000,000 shares authorized, 99,165,854 and 99,145,921 shares issued and outstanding, respectively	992	991
Additional paid in capital	1,968,493	1,968,217
Cumulative net income	205,028	108,144
Cumulative other comprehensive income	139	60,427
Cumulative common distributions	(893,002)	(807,736)
Total shareholders’ equity	1,281,650	1,330,043
Total liabilities and shareholders’ equity	$ 3,507,769	$ 3,703,565

CONDENSED CONSOLIDATED BALANCE3

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Common shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares of beneficial interest, shares authorized (in shares)	150,000,000	150,000,000
Common shares of beneficial interest, shares issued (in shares)	99,165,854	99,145,921
Common shares of beneficial interest, shares outstanding (in shares)	99,165,854	99,145,921

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Rental income	$ 108,085	$ 69,887	$ 216,802	$ 139,183
Expenses:
Real estate taxes	12,365	7,941	25,330	16,118
Other operating expenses	21,599	15,187	44,436	29,179
Depreciation and amortization	42,671	20,663	86,875	41,168
Loss on impairment of real estate	(316)	0	5,800	0
General and administrative	4,449	5,087	14,055	9,049
Total expenses	86,786	53,050	189,203	104,292
Operating income	21,299	16,837	27,599	34,891
Dividend income	304	304	608	608
Unrealized gain on equity securities	10,321	0	23,252	0
Interest income	149	67	265	128
Interest expense (including net amortization of debt premiums and discounts and debt issuance costs of $892, $808, $1856 and $1,615, respectively)	(23,304)	(13,963)	(46,070)	(27,544)
Net gain on issuance of shares by Select Income REIT	8	21	8	21
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	8,777	3,266	5,662	8,104
Income tax expense	(83)	(25)	(115)	(43)
Equity in net earnings of investees	3,672	8,581	13,384	11,320
Income from continuing operations	12,366	11,822	18,931	19,381
Loss from discontinued operations	0	(145)	0	(289)
Income before gain on sale of real estate	12,366	11,677	18,931	19,092
Gain on sale of real estate	17,329	0	17,329	0
Net income attributed to SIR	29,695	11,677	36,260	19,092
Other comprehensive income (loss):
Unrealized gain (loss) on investment in equity securities	0	(1,032)	0	11,110
Equity in unrealized gain (loss) of investees	34	(332)	(7)	4,283
Other comprehensive income (loss)	34	(1,364)	(7)	15,393
Comprehensive income	29,729	10,313	36,253	34,485
Net income (loss)	29,695	11,677	36,260	19,092
Preferred units of limited partnership distributions	(93)	0	(371)	0
Net income available for common shareholders	$ 29,602	$ 11,677	$ 35,889	$ 19,092
Weighted average common shares outstanding (basic) (in shares)	99,051	71,088	99,046	71,083
Weighted average common shares outstanding (diluted) (in shares)	99,064	71,119	99,050	71,109
Per common share amounts (basic and diluted):
Income from continuing operations (in dollars per share)	$ 0.30	$ 0.17	$ 0.37	$ 0.27
Loss from discontinued operations (in dollars per share)	0	0	0	0
Net income available for common shareholders (in dollars per share)	$ 0.30	$ 0.16	$ 0.36	$ 0.27
Utility expenses
Expenses:
Utility expenses	$ 6,018	$ 4,172	$ 12,707	$ 8,778

CONDENSED CONSOLIDATED STATEME5

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Net amortization of debt premiums and discounts and deferred financing fees	$ 892	$ 808	$ 1,856	$ 1,615

CONDENSED CONSOLIDATED STATEME6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 36,260	$ 19,092
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	34,037	23,398
Net amortization of debt premiums and discounts and debt issuance costs	1,856	1,615
Gain on sale of real estate	(17,329)	0
Straight line rental income	(5,835)	(2,404)
Amortization of acquired real estate leases	52,238	17,209
Amortization of deferred leasing costs	2,288	1,797
Other non-cash (income) expenses, net	(2)	193
Loss on impairment of real estate	5,800	0
Unrealized gain on equity securities	(23,252)	0
Equity in net earnings of investees	(13,384)	(11,320)
Net gain on issuance of shares by Select Income REIT	(8)	(21)
Distributions of earnings from Select Income REIT	14,590	10,817
Change in assets and liabilities:
Deferred leasing costs	(4,141)	(2,087)
Rents receivable	4,870	2,872
Other assets	4,870	(3,071)
Accounts payable and accrued expenses	(1,631)	9,871
Due to related persons	2,270	1,841
Net cash provided by operating activities	93,497	69,802
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate acquisitions and deposits	0	(12,648)
Real estate improvements	(21,324)	(21,996)
Distributions in excess of earnings from Select Income REIT	10,827	14,600
Distributions in excess of earnings from unconsolidated joint ventures	2,233	0
Proceeds from sale of properties, net	142,189	0
Net cash provided by (used in) investing activities	133,925	(20,044)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of mortgage notes payable	(1,808)	(761)
Borrowings on unsecured revolving credit facility	70,000	45,000
Repayments on unsecured revolving credit facility	(188,000)	(50,000)
Repurchase of common shares	(18)	(5)
Redemption of preferred units of limited partnership	(20,221)	0
Preferred units of limited partnership distributions	(646)	0
Distributions to common shareholders	(85,266)	(61,212)
Net cash used in financing activities	(225,959)	(66,978)
Increase (decrease) in cash and cash equivalents and restricted cash	1,463	(17,220)
Cash and cash equivalents and restricted cash at beginning of period	19,680	30,471
Cash and cash equivalents and restricted cash at end of period	$ 21,143	$ 13,251

CONDENSED CONSOLIDATED STATEME7

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - Supplemental Cash Flow - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Supplemental cash flow information
Interest paid	$ 43,958	$ 25,747
Income taxes paid	38	82
Supplemental disclosure of cash and cash equivalents and restricted cash
Cash and cash equivalents	18,695	12,907
Restricted cash	2,448	344
Total cash and cash equivalents and restricted cash reported in the statements of cash flows	$ 21,143	$ 13,251

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of Government Properties Income Trust and its subsidiaries, or the Company, GOV, we, us or our, are unaudited. Certain information and 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 for the year ended December 31, 2017 , or our Annual Report. In the opinion of management, all adjustments, consisting of normal recurring accruals considered necessary for a fair statement of results for the interim period have been included. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated. Our 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' condensed consolidated financial statements to conform to the current year’s presentation. The preparation of these 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 purchase price allocations, useful lives of fixed assets, assessment of impairment of real estate and equity method investments and the valuation of intangible assets.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements On January 1, 2018, we adopted the Financial Accounting Standards Board, or FASB, Accounting Standards Update, or ASU, No. 2014-09 (and related clarifying guidance issued by the FASB), Revenue From Contracts With Customers , which outlines a comprehensive model for entities to use in accounting for revenue arising from contracts with customers. ASU No. 2014-09 states that “an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.” While ASU No. 2014-09 specifically references contracts with customers, it may apply to certain other transactions such as the sale of real estate or equipment. A substantial portion of our revenue consists of rental income from leasing arrangements, which is specifically excluded from ASU No. 2014-09. We have adopted ASU No. 2014-09 using the modified retrospective approach, which resulted in an adjustment to reclassify a previous deferred gain on sale of real estate of $712 from accounts payable and other liabilities to cumulative net income. The adoption of ASU No. 2014-09 did not have a material impact on the amount or timing of our revenue recognition in our condensed consolidated financial statements except for profit recognition on real estate sales. On January 1, 2018, we adopted FASB ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which changes how entities measure certain equity investments and present changes in the fair value of financial liabilities measured under the fair value option that are attributable to their own credit. The implementation of ASU No. 2016-01 resulted in the reclassification of historical changes in the fair value of our available for sale equity securities of $45,116 from cumulative other comprehensive income to cumulative net income. We also reclassified $15,165 from cumulative other comprehensive income to cumulative net income for our share of cumulative other comprehensive income of certain of our equity method investees. Effective January 1, 2018, changes in the fair value of our equity securities are recorded through earnings in accordance with ASU No. 2016-01. On January 1, 2018, we adopted FASB ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which clarifies how companies present and classify certain cash receipts and cash payments in the statements of cash flows. The implementation of this update resulted in the reclassification of $1,472 of accretion recorded in our equity in the earnings of Select Income REIT, or SIR, from cash flow from investing activities to cash flow from operating activities for the six months ended June 30, 2017. See Note 12 for further information regarding our investment in SIR. On January 1, 2018, we adopted FASB ASU No. 2016-18, Restricted Cash , which requires companies to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. The implementation of ASU 2016-18 resulted in an increase of $186 of net cash provided by operating activities for the six months ended June 30, 2017. This update also requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheets. As a result, amounts included in restricted cash on our condensed consolidated balance sheets are included with cash and cash equivalents on the condensed consolidated statements of cash flows. Restricted cash, which consists of amounts escrowed for future real estate taxes, insurance, leasing costs, capital expenditures and debt service, as required by certain of our mortgage debts, totaled $2,448 and $344 as of June 30, 2018 and 2017, respectively. The adoption of this update did not change our balance sheet presentation. In February 2016, the FASB issued ASU No. 2016-02, Leases , which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). ASU No. 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease. A lessee is also required to record a right of use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales type leases, direct financing leases and operating leases. ASU No. 2016-02 is effective for reporting periods beginning after December 15, 2018, with early adoption permitted. We are currently assessing the potential impact the adoption of ASU No. 2016-02 will have in our condensed consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which requires that entities use a new forward looking “expected loss” model that generally will result in the earlier recognition of allowance for credit losses. The measurement of expected credit losses is based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU No. 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2016-13 will have in our condensed consolidated financial statements. We currently expect to adopt the standard using the modified retrospective approach. In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting , which aligns the measurement and classification guidance for share based payments to nonemployees with the guidance for share based payments to employees, with certain exceptions. ASU No. 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2018-07 will have in our condensed consolidated financial statements.

Weighted Average Common Shares

Weighted Average Common Shares	6 Months Ended
	Jun. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Weighted Average Common Shares	Weighted Average Common Shares The following table provides a reconciliation of the weighted average number of common shares used in the calculation of basic and diluted earnings per share (in thousands): For the Three Months For the Six Months Ended June 30, Ended June 30, 2018 2017 2018 2017 Weighted average common shares for basic earnings per share 99,051 71,088 99,046 71,083 Effect of dilutive securities: unvested share awards 13 31 4 26 Weighted average common shares for diluted earnings per share 99,064 71,119 99,050 71,109

Real Estate Properties

Real Estate Properties	6 Months Ended
	Jun. 30, 2018
Real Estate [Abstract]
Real Estate Properties	Real Estate Properties As of June 30, 2018 , we wholly owned 105 properties ( 164 buildings), with an aggregate undepreciated carrying value of $2,845,449 , and had a noncontrolling ownership interest in two unconsolidated joint ventures that owned two properties ( three buildings). We generally lease space at our properties on a gross lease or modified gross lease basis pursuant to fixed term contracts expiring between 2018 and 2034. Our leases generally require us to pay all or some property operating expenses and to provide all or most property management services. During the three months ended June 30, 2018 , we entered into 37 leases for 396,359 rentable square feet, for a weighted (by rentable square feet) average lease term of 6.2 years and we made commitments for $6,810 of leasing related costs. During the six months ended June 30, 2018 , we entered into 70 leases for 676,778 rentable square feet, for a weighted (by rentable square feet) average lease term of 5.9 years and we made commitments for $14,808 of leasing related costs. As of June 30, 2018 , we have estimated unspent leasing related obligations of $32,609 . We regularly evaluate whether events or changes in circumstances have occurred that could indicate an impairment in the value of our long lived assets. If there is an indication that the carrying value of an asset is not recoverable, we estimate the projected undiscounted cash flows to determine if an impairment loss should be recognized. We determine the amount of any impairment loss by comparing the historical carrying value to estimated fair value. We estimate fair value through an evaluation of recent financial performance and projected discounted cash flows using standard industry valuation techniques. In addition to evaluating for impairment upon the events or changes in circumstances described above, we regularly evaluate the remaining lives of our long lived assets. If we change our estimate of the remaining lives, we allocate the carrying value of the affected assets over their revised remaining lives. Disposition Activities In March 2018, we sold an office property ( one building) located in Minneapolis, MN with 193,594 rentable square feet for $20,000 , excluding closing costs. We recorded a $640 loss on impairment of real estate to reduce the carrying value of this property to its estimated fair value less costs to sell during the three months ended March 31, 2018. In February 2018, we entered an agreement to sell an office property ( one building) located in Safford, AZ with 36,139 rentable square feet for $8,250 . We recorded a $2,453 loss on impairment of real estate to reduce the carrying value of the property to its estimated fair value less costs to sell in the three months ended March 31, 2018. In April 2018, we terminated the sales agreement and removed this property from held for sale status. We recorded a $322 adjustment to impairment of real estate to increase the carrying value of the property to its estimated fair value in the three months ended June 30, 2018. In May 2018, we sold an office property ( one building) located in New York, NY with 187,060 rentable square feet for $118,500 , excluding closing costs. We recorded a $17,329 gain on sale of real estate during the three months ended June 30, 2018 as a result of this sale. In May 2018, we sold an office property ( one building) located in Sacramento, CA with 110,500 rentable square feet for $10,755 , excluding closing costs. We recorded a loss on impairment of real estate of $3,023 and $6 to reduce the carrying value of this property to its estimated fair value less costs to sell during the three months ended March 31, 2018 and June 30, 2018 , respectively. As part of our long term plans to reduce our leverage, we expect to sell additional properties. We are marketing or plan to market for sale 24 properties ( 56 buildings) with an aggregate carrying value of $506,741 as of June 30, 2018 . These properties did not meet the held for sale criteria as of June 30, 2018 . We cannot be sure we will sell any of our properties that we are marketing or plan to market for sale or sell them for prices in excess of our carrying values or that we will not recognize impairment losses with respect to these properties. Pro Forma Financial Information On October 2, 2017, we acquired First Potomac Realty Trust, or FPO, pursuant to a merger transaction, as a result of which we acquired 35 office properties ( 72 buildings) with 6,028,072 rentable square feet and FPO's 50% and 51% interests in two joint ventures that own two properties ( three buildings) with 443,867 rentable square feet, or collectively, the FPO Transaction. The aggregate value we paid at the closing of the FPO Transaction was $1,370,888 . We financed the FPO Transaction with the assumption of certain FPO mortgage debt, borrowings under our revolving credit facility and cash on hand, including net proceeds from our public offerings of common shares and senior unsecured notes. The following table presents our pro forma results of operations for the six months ended June 30, 2017 as if the FPO Transaction and related financing activities had occurred on January 1, 2017. The historical FPO results of operations included in this pro forma financial information have been adjusted to eliminate the results of operations of FPO properties and joint venture interests that were sold from January 1, 2017 to October 2, 2017, the closing date of the FPO Transaction. The effect of these adjustments was a decrease in pro forma rental income of $804 and a decrease in net income of $46,881 for the six months ended June 30, 2017. This pro forma financial information is not necessarily indicative of what our actual financial position or results of operations would have been for the periods presented or for any future period. Differences could result from numerous factors, including future changes in our portfolio of investments, capital structure, property level operating expenses and revenues, including rents expected to be received pursuant to our existing leases or leases we may enter during and after 2018, changes in interest rates and other reasons. Actual future results are likely to be different from amounts presented in this pro forma financial information and such differences could be significant. Six Months Ended June 30, 2017 Rental income $ 219,784 Net loss (1,613 ) Net loss per share $ 0.02 Unconsolidated Joint Ventures We own noncontrolling interests in two joint ventures that own two properties ( three buildings). We account for these investments under the equity method of accounting. As of June 30, 2018 , our investment in unconsolidated joint ventures consisted of the following: Joint Venture GOV Ownership GOV Carrying Value of Investment at June 30, 2018 Property Type Number of Buildings Location Square Feet Prosperity Metro Plaza 51% $ 25,669 Office 2 Fairfax, VA 328,456 1750 H Street, NW 50% 21,043 Office 1 Washington, DC 115,411 Total $ 46,712 3 443,867 The following table provides a summary of the mortgage debt of our unconsolidated joint ventures: Joint Venture Interest Rate (1) Maturity Date Principal Balance at June 30, 2018 (2) Prosperity Metro Plaza 4.09% 12/1/2029 $ 50,000 1750 H Street, NW 3.69% 8/1/2024 32,000 Weighted Average/Total 3.93% $ 82,000 (1) Includes the effect of mark to market purchase accounting. (2) Reflects the entire balance of the debt secured by the properties and is not adjusted to reflect the interests in the joint venture we do not own. None of the debt is recourse to us. At June 30, 2018 , the aggregate $8,688 unamortized basis difference of our unconsolidated joint ventures is primarily attributable to the difference between the amount we paid to purchase our interest in these joint ventures, including transaction costs, and the historical carrying value of the net assets of these joint ventures. This difference is being amortized over the remaining useful life of the properties owned by these joint ventures and the resulting amortization expense is included in equity in net earnings of investees in our condensed consolidated statements of comprehensive income.

Revenue Recognition

Revenue Recognition	6 Months Ended
	Jun. 30, 2018
Revenue Recognition [Abstract]
Revenue Recognition	Revenue Recognition We recognize rental income from operating leases that contain fixed contractual rent changes on a straight line basis over the term of the lease agreements. Certain of our leases with government tenants provide the tenant the right to terminate before the lease expiration date if the legislature or other funding authority does not appropriate the funding necessary for the government tenant to meet its lease obligations; we have determined the fixed non-cancelable lease term of these leases to be the full term of the lease because we believe the occurrence of early terminations to be remote contingencies based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis. We increased rental income to record revenue on a straight line basis by $2,744 and $1,104 for the three months ended June 30, 2018 and 2017 , respectively, and $5,835 and $2,404 for the six months ended June 30, 2018 and 2017 , respectively. Rents receivable include $32,001 and $27,267 of straight line rent receivables, net of allowance for doubtful accounts of $1,426 and $1,503 at June 30, 2018 and December 31, 2017 , respectively.

Concentration

Concentration	6 Months Ended
	Jun. 30, 2018
Risks and Uncertainties [Abstract]
Concentration	Concentration Tenant and Credit Concentration We define annualized rental income as the annualized contractual base rents from our tenants pursuant to our lease agreements as of the measurement date, plus straight line rent adjustments and estimated recurring expense reimbursements to be paid to us, and excluding lease value amortization. The U.S. Government, 13 state governments and three other government tenants combined were responsible for approximately 61.9% and 87.6% of our annualized rental income as of June 30, 2018 and 2017 , respectively. The U.S. Government is our largest tenant by annualized rental income and was responsible for approximately 45.2% and 59.6% of our annualized rental income as of June 30, 2018 and 2017 , respectively. Geographic Concentration At June 30, 2018 , our 105 consolidated properties ( 164 buildings) were located in 30 states and the District of Columbia. Consolidated properties located in Virginia, the District of Columbia, Maryland, California and Georgia were responsible for 24.0% , 18.1% , 15.5% , 9.4% and 6.1% of our annualized rental income as of June 30, 2018 , respectively. Consolidated properties located in the metropolitan Washington, D.C. market area were responsible for approximately 44.6% of our annualized rental income as of June 30, 2018 .

Indebtedness

Indebtedness	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Indebtedness	Indebtedness Our principal debt obligations at June 30, 2018 were: (1) $452,000 of outstanding borrowings under our $750,000 unsecured revolving credit facility; (2) $550,000 aggregate outstanding principal amount of unsecured term loans; (3) $960,000 aggregate outstanding principal amount of senior unsecured notes; and (4) $181,339 aggregate outstanding principal amount of mortgage notes. Our $750,000 revolving credit facility, our $300,000 term loan and our $250,000 term loan are governed by a credit agreement, or our credit agreement, with a syndicate of institutional lenders that includes a number of features common to all of these credit arrangements. Our credit agreement also includes a feature under which the maximum aggregate borrowing availability may be increased to up to $2,500,000 on a combined basis in certain circumstances. Our $750,000 revolving credit facility is available for general business purposes, including acquisitions. The maturity date of our revolving credit facility is January 31, 2019 and, subject to the payment of an extension fee and meeting other conditions, we have an option to extend the stated maturity date of our revolving credit facility by one year to January 31, 2020. We can borrow, repay and reborrow funds available under our revolving credit facility until maturity and no principal repayment is due until maturity. We are required to pay interest at a rate of LIBOR plus a premium, which was 125 basis points per annum at June 30, 2018 , on borrowings under our revolving credit facility. We also pay a facility fee on the total amount of lending commitments under our revolving credit facility, which was 25 basis points per annum at June 30, 2018 . Both the interest rate premium and the facility fee are subject to adjustment based upon changes to our credit ratings. As of June 30, 2018 , the annual interest rate payable on borrowings under our revolving credit facility was 3.2% and the weighted average annual interest rate for borrowings under our revolving credit facility was 3.0% and 2.2% for the three months ended June 30, 2018 and 2017 , respectively, and 2.9% and 2.1% for the six months ended June 30, 2018 and 2017 , respectively. As of both June 30, 2018 and July 31, 2018 , we had $452,000 outstanding under our revolving credit facility. Our $300,000 term loan, which matures on March 31, 2020, is prepayable without penalty at any time. We are required to pay interest at a rate of LIBOR plus a premium, which was 140 basis points per annum at June 30, 2018 , on the amount outstanding under our $300,000 term loan. The interest rate premium is subject to adjustment based upon changes to our credit ratings. As of June 30, 2018 , the annual interest rate for the amount outstanding under our $300,000 term loan was 3.5% . The weighted average annual interest rate under our $300,000 term loan was 3.3% and 2.4% for the three months ended June 30, 2018 and 2017 , respectively, and 3.2% and 2.3% for the six months ended June 30, 2018 and 2017 , respectively. Our $250,000 term loan, which matures on March 31, 2022, is prepayable without penalty at any time. We are required to pay interest at a rate of LIBOR plus a premium, which was 180 basis points per annum as of June 30, 2018 , on the amount outstanding under our $250,000 term loan. The interest rate premium is subject to adjustment based upon changes to our credit ratings. As of June 30, 2018 , the annual interest rate for the amount outstanding under our $250,000 term loan was 3.9% . The weighted average annual interest rate under our $250,000 term loan was 3.7% and 2.8% for the three months ended June 30, 2018 and 2017 , respectively, and 3.6% and 2.7% for the six months ended June 30, 2018 and 2017 , respectively. Our credit agreement and senior unsecured notes indentures and their supplements provide for acceleration of payment of all amounts due thereunder upon the occurrence and continuation of certain events of default, such as, in the case of our credit agreement, a change of control of us, which includes The RMR Group LLC, or RMR LLC, ceasing to act as our business and property manager. Our credit agreement and our senior unsecured notes indentures and their supplements also contain a number of covenants, including covenants that restrict our ability to incur debts, require us to maintain certain financial ratios and, in the case of our credit agreement, restrict our ability to make distributions under certain circumstances. We believe we were in compliance with the terms and conditions of the respective covenants under our credit agreement and senior unsecured notes indentures and their supplements at June 30, 2018 . At June 30, 2018 , eight of our consolidated properties ( eight buildings) with an aggregate net book value of $422,583 were encumbered by eight mortgages for an aggregate principal amount of $181,339 . Our mortgage notes are non-recourse, subject to certain limited exceptions and do not contain any material financial covenants.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities The table below presents certain of our assets measured at fair value at June 30, 2018 , categorized by the level of inputs, as defined in the fair value hierarchy under GAAP, used in the valuation of each asset: Fair Value at Reporting Date Using Quoted Prices in Significant Active Markets for Significant Other Unobservable Identical Assets Observable Inputs Inputs Description Total (Level 1) (Level 2) (Level 3) Recurring Fair Value Measurements Assets: Investment in RMR Inc. (1) $ 95,256 $ 95,256 $ — $ — (1) Our 1,214,225 shares of class A common stock of The RMR Group Inc., or RMR Inc., which are included in other assets in our condensed consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs as defined in the fair value hierarchy under GAAP). Our historical cost basis for these shares is $26,888 as of June 30, 2018 . During the three and six months ended June 30, 2018 , we recorded an unrealized gain of $10,321 and $23,252 , respectively, to adjust our investment in RMR Inc. to its fair value. In addition to the assets described in the table above, our financial instruments include our cash and cash equivalents, restricted cash, rents receivable, mortgage notes receivable, accounts payable, revolving credit facility, term loans, senior unsecured notes, mortgage notes payable, amounts due to related persons, other accrued expenses and security deposits. At June 30, 2018 and December 31, 2017 , the fair values of our financial instruments approximated their carrying values in our condensed consolidated financial statements due to their short term nature or variable interest rates, except as follows: As of June 30, 2018 As of December 31, 2017 Carrying Amount (1) Fair Value Carrying Amount (1) Fair Value Senior unsecured notes, 3.75% interest rate, due in 2019 $ 348,668 $ 351,141 $ 348,096 $ 354,993 Senior unsecured notes, 5.875% interest rate, due in 2046 300,404 316,200 300,232 320,416 Senior unsecured notes, 4.000% interest rate, due in 2022 296,274 297,063 295,812 302,655 Mortgage note payable, 4.050% interest rate, due in 2030 (2) 64,392 63,592 64,293 65,198 Mortgage note payable, 5.720% interest rate, due in 2020 (2) 35,428 35,346 36,085 36,332 Mortgage note payable, 4.220% interest rate, due in 2022 (2) 27,576 27,753 27,906 28,432 Mortgage note payable, 4.800% interest rate, due in 2023 (2) 25,270 25,514 25,501 25,904 Mortgage note payable, 5.877% interest rate, due in 2021 (2) 13,503 14,156 13,620 14,565 Mortgage note payable, 7.000% interest rate, due in 2019 (2) 8,190 8,265 8,391 8,555 Mortgage note payable, 8.150% interest rate, due in 2021 (2) 3,531 3,686 4,111 4,340 Mortgage note payable, 4.260% interest rate, due in 2020 (2) 3,096 3,088 3,193 3,216 $ 1,126,332 $ 1,145,804 $ 1,127,240 $ 1,164,606 (1) Carrying amount includes certain unamortized debt issuance costs and unamortized premiums and discounts. (2) We assumed these mortgages in connection with our acquisitions of the encumbered properties. The stated interest rates for these mortgage debts are the contractually stated rates. We recorded the assumed mortgages at estimated fair value on the date of acquisition and we are amortizing the fair value premiums, if any, to interest expense over the respective terms of the mortgages to reduce interest expense to the estimated market interest rates as of the date of acquisition. We estimated the fair value of our senior unsecured notes due 2019 and due 2022 using an average of the bid and ask price of the notes as of the measurement date (Level 2 inputs as defined in the fair value hierarchy under GAAP). We estimated the fair value of our senior unsecured notes due 2046 based on the closing price on The Nasdaq Stock Market LLC, or Nasdaq, as of the measurement date (Level 1 inputs as defined in the fair value hierarchy under GAAP). We estimated the fair values of our mortgage notes payable by using discounted cash flow analyses and currently prevailing market terms as of the measurement date (Level 3 inputs as defined in the fair value hierarchy under GAAP). Because Level 3 inputs are unobservable, our estimated fair value may differ materially from the actual fair value.

Shareholders' Equity

Shareholders' Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity Share Awards On April 3, 2018, in accordance with our Trustee compensation arrangements, and in connection with the election of one of our Managing Trustees, we granted 3,000 of our common shares, valued at $13.59 per share, the closing price of our common shares on Nasdaq on that day, to the Managing Trustee who was elected as a Managing Trustee that day. On May 24, 2018, in accordance with our Trustee compensation arrangements, we granted 3,000 of our common shares, valued at $14.10 per share, the closing price of our common shares on Nasdaq on that day, to each of our six Trustees as part of their annual compensation. Share Purchases On January 1, 2018, we purchased 617 of our common shares valued at a price per share of $18.54 , the closing price of our common shares on Nasdaq on December 29, 2017, from a former employee of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. On May 24, 2018, we purchased 450 of our common shares valued at a price per share of $14.10 , the closing price of our common shares on Nasdaq on that day, from one of our Trustees in satisfaction of tax withholding and payment obligations in connection with an award of our common shares. Distributions On February 26, 2018, we paid a regular quarterly distribution to common shareholders of record on January 29, 2018 of $0.43 per share, or $42,632 . On May 21, 2018, we paid a regular quarterly distribution to common shareholders of record on April 30, 2018 of $0.43 per share, or $42,634 . On July 19, 2018, we declared a regular quarterly distribution payable to common shareholders of record on July 30, 2018 of $0.43 per share, or $42,641 . We expect to pay this distribution on or about August 20, 2018. Cumulative Other Comprehensive Income Cumulative other comprehensive income represents our share of the comprehensive income of our equity method investees, SIR and Affiliates Insurance Company, or AIC. See Notes 11 and 12 for further information regarding these investments. The following table presents changes in the amounts we recognized in cumulative other comprehensive income by component for the three and six months ended June 30, 2018 : Three Months Ended June 30, 2018 Unrealized Gain Equity in on Investment Unrealized in Equity Gain Securities of Investees Total Balance at March 31, 2018 $ — $ 945 $ 945 Amounts reclassified from cumulative other comprehensive income to cumulative net income — (840 ) (840 ) Other comprehensive income before reclassifications — 70 70 Amounts reclassified from cumulative other comprehensive income to net income (1) — (36 ) (36 ) Net current period other comprehensive income — 34 34 Balance at June 30, 2018 $ — $ 139 $ 139 Six Months Ended June 30, 2018 Unrealized Gain Equity in on Investment Unrealized in Equity Gain (Loss) Securities of Investees Total Balance at December 31, 2017 $ 45,116 $ 15,311 $ 60,427 Amounts reclassified from cumulative other comprehensive income to cumulative net income (45,116 ) (15,165 ) (60,281 ) Other comprehensive income before reclassifications — 48 48 Amounts reclassified from cumulative other comprehensive income to net income (1) — (55 ) (55 ) Net current period other comprehensive loss — (7 ) (7 ) Balance at June 30, 2018 $ — $ 139 $ 139 (1) Amounts reclassified from cumulative other comprehensive loss to net income are included in equity in net earnings of investees in our condensed consolidated statements of comprehensive income. Preferred Units of Limited Partnership On May 1, 2018, one of our subsidiaries redeemed all 1,813,504 of its outstanding 5.5% Series A Cumulative Preferred Units for $11.15 per unit plus accrued and unpaid distributions (an aggregate of $20,310 ).

Business and Property Managemen

Business and Property Management Agreements with RMR LLC	6 Months Ended
	Jun. 30, 2018
Property Management Fee [Abstract]
Business and Property Management Agreements with RMR LLC	Business and Property Management Agreements with RMR LLC We have no employees. The personnel and various services we require to operate our business are provided to us by RMR LLC. We have two agreements with RMR LLC to provide management services to us: (1) a business management agreement, which relates to our business generally; and (2) a property management agreement, which relates to our property level operations. Pursuant to our business management agreement with RMR LLC, we recognized net business management fees of $2,175 and $3,646 for the three months ended June 30, 2018 and 2017 , respectively, and $9,484 and $6,350 for the six months ended June 30, 2018 and 2017 , respectively. The net business management fees payable to RMR LLC for the three months ended June 30, 2018 , include the reversal of $2,150 of previously accrued business management incentive fee expense and the accrual of $893 of estimated business management incentive fee expense for the three months ended June 30, 2018 and 2017, respectively. The net business management fees payable to RMR LLC include $737 and $893 of estimated business management fee expense for the six months ended June 30, 2018 and 2017, respectively. The amount of estimated business management incentive fees that we accrue for a period, if any, are based on our common share total return, as defined under our business management agreement with RMR LLC, as of the end of the applicable period. Although we recognized estimated incentive fees in accordance with GAAP, the actual amount of incentive fees payable to RMR LLC for 2018, if any, will be based on our common share total return, as defined, for the three year period ending December 31, 2018, and will be payable in 2019. No incentive management fee was payable for the year ended December 31, 2017. These amounts are included in general and administrative expenses in our condensed consolidated statements of comprehensive income. Pursuant to our property management agreement with RMR LLC, we recognized aggregate net property management and construction supervision fees of $3,437 and $2,567 for the three months ended June 30, 2018 and 2017 , respectively, and $6,786 and $5,033 for the six months ended June 30, 2018 and 2017 , respectively. These amounts are included in other operating expenses or have been capitalized, as appropriate, in our condensed consolidated financial statements. We are generally responsible for all of our operating expenses, including certain expenses incurred by RMR LLC on our behalf. Our property level operating expenses, including certain payroll and related costs incurred by RMR LLC, are generally incorporated into rents charged to our tenants. We reimbursed RMR LLC $5,052 and $3,655 for property management related expenses for the three months ended June 30, 2018 and 2017 , respectively, and $10,021 and $7,046 for property management related expenses for the six months ended June 30, 2018 and 2017 , respectively, which amounts are included in other operating expenses in our condensed consolidated statements of comprehensive income. In addition, we are responsible for our share of RMR LLC’s costs for providing our internal audit function. The amounts we recognized as expense for internal audit costs were $54 and $67 for the three months ended June 30, 2018 and 2017 , respectively, and $123 and $135 for the six months ended June 30, 2018 and 2017 , respectively. These amounts are included in general and administrative expenses in our condensed consolidated statements of comprehensive income.

Related Person Transactions

Related Person Transactions	6 Months Ended
	Jun. 30, 2018
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions We have relationships and historical and continuing transactions with RMR LLC, RMR Inc., SIR, AIC and others related to them, including other companies to which RMR LLC or its subsidiaries provide management services and which have trustees, directors and officers who are also our Trustees or officers. Our Manager, RMR LLC. We have two agreements with RMR LLC to provide management services to us. See Note 10 for further information regarding our management agreements with RMR LLC. We lease office space to RMR LLC in certain of our properties for RMR LLC's property management offices. We recognized rental income from RMR LLC for leased office space of $282 and $90 for the three months ended June 30, 2018 and 2017, respectively, and $500 and $182 for the six months ended June 30, 2018 and 2017, respectively. Our office space leases with RMR LLC are terminable by RMR LLC if our management agreements with RMR LLC are terminated. RMR Inc. RMR LLC is a majority owned subsidiary of RMR Inc. and RMR Inc. is the managing member of RMR LLC. Adam D. Portnoy, one of our Managing Trustees, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., a managing director, president and chief executive officer of RMR Inc. and an officer of RMR LLC. Mark L. Kleifges, our other Managing Trustee and our Chief Financial Officer and Treasurer, and David M. Blackman, our President and Chief Executive Officer, also serve as executive officers of RMR LLC. As of June 30, 2018 , we owned 1,214,225 shares of class A common stock of RMR Inc. See Note 8 for further information regarding our investment in RMR Inc. SIR . We are SIR’s largest shareholder. As of June 30, 2018 , we owned 24,918,421 of SIR's common shares, or approximately 27.8% of its outstanding common shares. Adam D. Portnoy, one of our Managing Trustees, also serves as a managing trustee of SIR, and our President and Chief Executive Officer also serves as a managing trustee and the president and chief executive officer of SIR. RMR LLC provides management services to SIR and us. See Note 12 for further information regarding our investment in SIR. AIC . We, ABP Trust, SIR and four other companies to which RMR LLC provides management services currently own AIC in equal amounts. We and the other AIC shareholders participate in a combined property insurance program arranged and reinsured in part by AIC. We currently expect to pay, as of June 30, 2018, aggregate annual premiums, including taxes and fees, of approximately $1,211 in connection with this insurance program for the policy year ending June 30, 2019, which amount may be adjusted from time to time as we acquire and dispose of properties that are included in this insurance program. As of June 30, 2018 and December 31, 2017, our investment in AIC had a carrying value of $8,272 and $8,304 , respectively. These amounts are included in other assets in our condensed consolidated balance sheets. We recognized income related to our investment in AIC, which is presented as equity in earnings of investees in our condensed consolidated statements of comprehensive income. Our other comprehensive income includes our proportionate part of unrealized gains on securities that are owned by AIC related to our investment in AIC. For further information about these and other such relationships and certain other related person transactions, refer to our Annual Report.

Equity Investment in Select Inc

Equity Investment in Select Income REIT	6 Months Ended
	Jun. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Equity Investment in Select Income REIT	Equity Investment in Select Income REIT As described in Note 11, as of June 30, 2018 , we owned 24,918,421 , or approximately 27.8% , of the then outstanding SIR common shares. SIR is a real estate investment trust that owns properties that are primarily net leased to single tenants. We account for our investment in SIR under the equity method. Under the equity method, we record our proportionate share of SIR’s net income as equity in net earnings of investees in our condensed consolidated statements of comprehensive income. We recorded $4,301 and $8,207 of equity in the earnings of SIR for the three months ended June 30, 2018 and 2017 , respectively, and $14,590 and $10,818 of equity in the earnings of SIR for the six months ended June 30, 2018 and 2017 , respectively. Our other comprehensive income includes our proportionate share of SIR’s unrealized gains (losses) of $24 and ($389) for the three months ended June 30, 2018 and 2017 , respectively, and $75 and $4,103 for the six months ended June 30, 2018 and 2017 , respectively. The adjusted GAAP cost basis of our investments in SIR was less than our proportionate share of SIR’s total shareholders’ equity book value on the dates we acquired the shares. As of June 30, 2018 and December 31, 2017, our basis difference was $121,535 and $87,137 , respectively, and as required under GAAP, we are accreting this basis difference to earnings over the estimated remaining useful lives of certain real estate assets and intangible assets and liabilities owned by SIR. The increase in the basis difference primarily relates to SIR's capital finance activities and changes in its net equity during the six months ended June 30, 2018 . This accretion increased our equity in the earnings of SIR by $1,044 and $736 for the three months ended June 30, 2018 and 2017 , respectively, and $2,088 and $1,472 for the six months ended June 30, 2018 and 2017 , respectively. As of June 30, 2018 , our investment in SIR had a carrying value of $456,756 and a market value, based on the closing price of SIR common shares on Nasdaq on June 30, 2018 , of $559,917 . We periodically evaluate our equity investment in SIR for possible indicators of other than temporary impairment whenever events or changes in circumstances indicate the carrying amount of the investment might not be recoverable. These indicators may include the length of time the market value of our investment is below our cost basis, the financial condition of SIR, our intent and ability to be a long term holder of the investment and other considerations. If the decline in fair value is judged to be other than temporary, we may record an impairment charge to adjust the basis of the investment to its fair value. We received aggregate cash distributions from SIR of $12,708 during each of the three months ended June 30, 2018 and 2017 , and $25,417 and $25,416 during the six months ended June 30, 2018 and 2017 , respectively. The following presents summarized financial data of SIR as reported in SIR’s Quarterly Report on Form 10-Q for the quarter ended June 30, 2018 , or the SIR Quarterly Report. References in our condensed consolidated financial statements to the SIR Quarterly Report are included as references to the source of the data only, and the information in the SIR Quarterly Report is not incorporated by reference into our condensed consolidated financial statements. Condensed Consolidated Balance Sheets June 30, December 31, 2018 2017 Real estate properties, net $ 3,919,764 $ 3,905,616 Acquired real estate leases, net 445,616 477,577 Properties held for sale 5,829 5,829 Cash and cash equivalents 31,476 658,719 Rents receivable, net 122,795 127,672 Other assets, net 158,370 127,617 Total assets $ 4,683,850 $ 5,303,030 Unsecured revolving credit facility $ 105,000 $ — Industrial Logistics Properties Trust revolving credit facility 335,000 750,000 Unsecured term loan, net — 348,870 Senior unsecured notes, net 1,429,622 1,777,425 Mortgage notes payable, net 210,715 210,785 Assumed real estate lease obligations, net 64,372 68,783 Other liabilities 143,510 155,348 Total shareholders' equity attributable to SIR 2,077,159 1,991,819 Noncontrolling interest in consolidated subsidiary 318,472 — Total liabilities and shareholders' equity $ 4,683,850 $ 5,303,030 Condensed Consolidated Statements of Income Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Rental income $ 96,415 $ 97,041 $ 196,170 $ 194,385 Tenant reimbursements and other income 19,592 18,829 40,466 37,779 Total revenues 116,007 115,870 236,636 232,164 Real estate taxes 12,442 10,836 24,230 21,679 Other operating expenses 13,618 13,523 28,900 26,390 Depreciation and amortization 35,009 34,317 69,955 68,057 General and administrative 18,081 8,188 32,022 23,089 Write-off of straight line rents, net 10,626 — 10,626 12,517 Loss on asset impairment — — — 4,047 Loss on impairment of real estate assets — 229 — 229 Total expenses 89,776 67,093 165,733 156,008 Operating income 26,231 48,777 70,903 76,156 Dividend income 396 396 793 793 Unrealized gain on equity securities 13,488 — 30,388 — Interest income 110 7 620 20 Interest expense (22,667 ) (22,808 ) (46,159 ) (43,895 ) Loss on early extinguishment of debt — — (1,192 ) — Income before income tax expense and equity in earnings of an investee 17,558 26,372 55,353 33,074 Income tax expense (101 ) (85 ) (261 ) (187 ) Equity in earnings of an investee 7 374 51 502 Net income 17,464 26,661 55,143 33,389 Net income allocated to noncontrolling interest (5,765 ) — (10,244 ) — Net income attributed to SIR $ 11,699 $ 26,661 $ 44,899 $ 33,389 Weighted average common shares outstanding (basic) 89,393 89,338 89,388 89,334 Weighted average common shares outstanding (diluted) 89,416 89,362 89,398 89,356 Net income attributed to SIR per common share (basic and diluted) $ 0.13 $ 0.30 $ 0.50 $ 0.37

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Segment Information	Segment Information We operate in two separate reportable business segments: ownership of real estate properties and our equity method investment in SIR. Three Months Ended June 30, 2018 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 108,085 $ — $ — $ 108,085 Expenses: Real estate taxes 12,365 — — 12,365 Utility expenses 6,018 — — 6,018 Other operating expenses 21,599 — — 21,599 Depreciation and amortization 42,671 — — 42,671 Loss on impairment of real estate (316 ) — — (316 ) General and administrative — — 4,449 4,449 Total expenses 82,337 — 4,449 86,786 Operating income (loss) 25,748 — (4,449 ) 21,299 Dividend income — — 304 304 Unrealized gain on equity securities — — 10,321 10,321 Interest income 56 — 93 149 Interest expense (2,014 ) — (21,290 ) (23,304 ) Net gain on issuance of shares by Select Income REIT — 8 — 8 Income (loss) from continuing operations before income tax, equity in net earnings (losses) of investees and gain on sale of real estate 23,790 8 (15,021 ) 8,777 Income tax expense — — (83 ) (83 ) Equity in net earnings (losses) of investees (636 ) 4,301 7 3,672 Income (loss) from continuing operations before gain on sale of real estate 23,154 4,309 (15,097 ) 12,366 Gain on sale of real estate 17,329 — — 17,329 Net income (loss) $ 40,483 $ 4,309 $ (15,097 ) $ 29,695 Preferred units of limited partnership distributions — — (93 ) (93 ) Net income (loss) available for common shareholders $ 40,483 $ 4,309 $ (15,190 ) $ 29,602 Six Months Ended June 30, 2018 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 216,802 $ — $ — $ 216,802 Expenses: Real estate taxes 25,330 — — 25,330 Utility expenses 12,707 — — 12,707 Other operating expenses 44,436 — — 44,436 Depreciation and amortization 86,875 — — 86,875 Loss on impairment of real estate 5,800 — — 5,800 General and administrative — — 14,055 14,055 Total expenses 175,148 — 14,055 189,203 Operating income (loss) 41,654 — (14,055 ) 27,599 Dividend income — — 608 608 Unrealized gain on equity securities — — 23,252 23,252 Interest income 113 — 152 265 Interest expense (4,109 ) — (41,961 ) (46,070 ) Net gain on issuance of shares by Select Income REIT — 8 — 8 Income (loss) from continuing operations before income taxes, equity in net earnings (losses) of investees and gain on sale of real estate 37,658 8 (32,004 ) 5,662 Income tax expense — — (115 ) (115 ) Equity in net earnings (losses) of investees (1,257 ) 14,590 51 13,384 Income (loss) from continuing operations before gain on sale of real estate 36,401 14,598 (32,068 ) 18,931 Gain on sale of real estate 17,329 — — 17,329 Net income (loss) 53,730 14,598 (32,068 ) 36,260 Preferred units of limited partnership distributions — — (371 ) (371 ) Net income (loss) available for common shareholders $ 53,730 $ 14,598 $ (32,439 ) $ 35,889 As of June 30, 2018 Investment Investment in Real Estate in SIR Corporate Consolidated Total Assets $ 2,927,745 $ 456,756 $ 123,268 $ 3,507,769 Three Months Ended June 30, 2017 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 69,887 $ — $ — $ 69,887 Expenses: Real estate taxes 7,941 — — 7,941 Utility expenses 4,172 — — 4,172 Other operating expenses 15,187 — — 15,187 Depreciation and amortization 20,663 — — 20,663 General and administrative — — 5,087 5,087 Total expenses 47,963 — 5,087 53,050 Operating income (loss) 21,924 — (5,087 ) 16,837 Dividend income — — 304 304 Interest income 48 — 19 67 Interest expense (405 ) — (13,558 ) (13,963 ) Net gain on issuance of shares by Select Income REIT — 21 — 21 Income (loss) from continuing operations before income taxes and equity in net earnings of investee 21,567 21 (18,322 ) 3,266 Income tax expense — — (25 ) (25 ) Equity in net earnings of investees — 8,207 374 8,581 Income (loss) from continuing operations 21,567 8,228 (17,973 ) 11,822 Loss from discontinued operations (145 ) — — (145 ) Net income (loss) available for common shareholders $ 21,422 $ 8,228 $ (17,973 ) $ 11,677 Six Months Ended June 30, 2017 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 139,183 $ — $ — $ 139,183 Expenses: Real estate taxes 16,118 — — 16,118 Utility expenses 8,778 — — 8,778 Other operating expenses 29,179 — — 29,179 Depreciation and amortization 41,168 — — 41,168 General and administrative — — 9,049 9,049 Total expenses 95,243 — 9,049 104,292 Operating income (loss) 43,940 — (9,049 ) 34,891 Dividend income — — 608 608 Interest income 94 — 34 128 Interest expense (837 ) — (26,707 ) (27,544 ) Net gain on issuance of shares by Select Income REIT — 21 — 21 Income (loss) from continuing operations before income taxes and equity in net earnings of investee 43,197 21 (35,114 ) 8,104 Income tax expense — — (43 ) (43 ) Equity in net earnings of investees — 10,818 502 11,320 Income (loss) from continuing operations 43,197 10,839 (34,655 ) 19,381 Loss from discontinued operations (289 ) — — (289 ) Net income (loss) available for common shareholders $ 42,908 $ 10,839 $ (34,655 ) $ 19,092 As of December 31, 2017 Investment Investment in Real Estate in SIR Corporate Consolidated Total Assets $ 3,138,764 $ 467,499 $ 97,302 $ 3,703,565

Recent Accounting Pronounceme21

Recent Accounting Pronouncements (Policies)	6 Months Ended
	Jun. 30, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements On January 1, 2018, we adopted the Financial Accounting Standards Board, or FASB, Accounting Standards Update, or ASU, No. 2014-09 (and related clarifying guidance issued by the FASB), Revenue From Contracts With Customers , which outlines a comprehensive model for entities to use in accounting for revenue arising from contracts with customers. ASU No. 2014-09 states that “an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services.” While ASU No. 2014-09 specifically references contracts with customers, it may apply to certain other transactions such as the sale of real estate or equipment. A substantial portion of our revenue consists of rental income from leasing arrangements, which is specifically excluded from ASU No. 2014-09. We have adopted ASU No. 2014-09 using the modified retrospective approach, which resulted in an adjustment to reclassify a previous deferred gain on sale of real estate of $712 from accounts payable and other liabilities to cumulative net income. The adoption of ASU No. 2014-09 did not have a material impact on the amount or timing of our revenue recognition in our condensed consolidated financial statements except for profit recognition on real estate sales. On January 1, 2018, we adopted FASB ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities , which changes how entities measure certain equity investments and present changes in the fair value of financial liabilities measured under the fair value option that are attributable to their own credit. The implementation of ASU No. 2016-01 resulted in the reclassification of historical changes in the fair value of our available for sale equity securities of $45,116 from cumulative other comprehensive income to cumulative net income. We also reclassified $15,165 from cumulative other comprehensive income to cumulative net income for our share of cumulative other comprehensive income of certain of our equity method investees. Effective January 1, 2018, changes in the fair value of our equity securities are recorded through earnings in accordance with ASU No. 2016-01. On January 1, 2018, we adopted FASB ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which clarifies how companies present and classify certain cash receipts and cash payments in the statements of cash flows. The implementation of this update resulted in the reclassification of $1,472 of accretion recorded in our equity in the earnings of Select Income REIT, or SIR, from cash flow from investing activities to cash flow from operating activities for the six months ended June 30, 2017. See Note 12 for further information regarding our investment in SIR. On January 1, 2018, we adopted FASB ASU No. 2016-18, Restricted Cash , which requires companies to show the changes in the total of cash, cash equivalents, restricted cash and restricted cash equivalents in the statement of cash flows. The implementation of ASU 2016-18 resulted in an increase of $186 of net cash provided by operating activities for the six months ended June 30, 2017. This update also requires a reconciliation of the totals in the statement of cash flows to the related captions in the balance sheets. As a result, amounts included in restricted cash on our condensed consolidated balance sheets are included with cash and cash equivalents on the condensed consolidated statements of cash flows. Restricted cash, which consists of amounts escrowed for future real estate taxes, insurance, leasing costs, capital expenditures and debt service, as required by certain of our mortgage debts, totaled $2,448 and $344 as of June 30, 2018 and 2017, respectively. The adoption of this update did not change our balance sheet presentation. In February 2016, the FASB issued ASU No. 2016-02, Leases , which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). ASU No. 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight line basis over the term of the lease. A lessee is also required to record a right of use asset and a lease liability for all leases with a term of greater than 12 months regardless of their classification. Leases with a term of 12 months or less will be accounted for similar to existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales type leases, direct financing leases and operating leases. ASU No. 2016-02 is effective for reporting periods beginning after December 15, 2018, with early adoption permitted. We are currently assessing the potential impact the adoption of ASU No. 2016-02 will have in our condensed consolidated financial statements. In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , which requires that entities use a new forward looking “expected loss” model that generally will result in the earlier recognition of allowance for credit losses. The measurement of expected credit losses is based upon historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. ASU No. 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2016-13 will have in our condensed consolidated financial statements. We currently expect to adopt the standard using the modified retrospective approach. In June 2018, the FASB issued ASU No. 2018-07, Compensation-Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting , which aligns the measurement and classification guidance for share based payments to nonemployees with the guidance for share based payments to employees, with certain exceptions. ASU No. 2018-07 is effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are currently assessing the potential impact the adoption of ASU No. 2018-07 will have in our condensed consolidated financial statements.

Weighted Average Common Shares

Weighted Average Common Shares (Tables)	6 Months Ended
	Jun. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Weighted Average Common Share Amounts	The following table provides a reconciliation of the weighted average number of common shares used in the calculation of basic and diluted earnings per share (in thousands): For the Three Months For the Six Months Ended June 30, Ended June 30, 2018 2017 2018 2017 Weighted average common shares for basic earnings per share 99,051 71,088 99,046 71,083 Effect of dilutive securities: unvested share awards 13 31 4 26 Weighted average common shares for diluted earnings per share 99,064 71,119 99,050 71,109

Real Estate Properties (Tables)

Real Estate Properties (Tables)	6 Months Ended
	Jun. 30, 2018
Real Estate [Abstract]
Schedule of Pro Forma Information	The following table presents our pro forma results of operations for the six months ended June 30, 2017 as if the FPO Transaction and related financing activities had occurred on January 1, 2017. The historical FPO results of operations included in this pro forma financial information have been adjusted to eliminate the results of operations of FPO properties and joint venture interests that were sold from January 1, 2017 to October 2, 2017, the closing date of the FPO Transaction. The effect of these adjustments was a decrease in pro forma rental income of $804 and a decrease in net income of $46,881 for the six months ended June 30, 2017. This pro forma financial information is not necessarily indicative of what our actual financial position or results of operations would have been for the periods presented or for any future period. Differences could result from numerous factors, including future changes in our portfolio of investments, capital structure, property level operating expenses and revenues, including rents expected to be received pursuant to our existing leases or leases we may enter during and after 2018, changes in interest rates and other reasons. Actual future results are likely to be different from amounts presented in this pro forma financial information and such differences could be significant. Six Months Ended June 30, 2017 Rental income $ 219,784 Net loss (1,613 ) Net loss per share $ 0.02
Schedule of Joint Ventures	As of June 30, 2018 , our investment in unconsolidated joint ventures consisted of the following: Joint Venture GOV Ownership GOV Carrying Value of Investment at June 30, 2018 Property Type Number of Buildings Location Square Feet Prosperity Metro Plaza 51% $ 25,669 Office 2 Fairfax, VA 328,456 1750 H Street, NW 50% 21,043 Office 1 Washington, DC 115,411 Total $ 46,712 3 443,867 The following table provides a summary of the mortgage debt of our unconsolidated joint ventures: Joint Venture Interest Rate (1) Maturity Date Principal Balance at June 30, 2018 (2) Prosperity Metro Plaza 4.09% 12/1/2029 $ 50,000 1750 H Street, NW 3.69% 8/1/2024 32,000 Weighted Average/Total 3.93% $ 82,000 (1) Includes the effect of mark to market purchase accounting. (2) Reflects the entire balance of the debt secured by the properties and is not adjusted to reflect the interests in the joint venture we do not own. None of the debt is recourse to us.

Fair Value of Assets and Liab24

Fair Value of Assets and Liabilities (Tables)	6 Months Ended
	Jun. 30, 2018
Fair Value Disclosures [Abstract]
Schedule of assets measured on a recurring and non-recurring basis at fair value, categorized by the level of inputs used in the valuation assets	The table below presents certain of our assets measured at fair value at June 30, 2018 , categorized by the level of inputs, as defined in the fair value hierarchy under GAAP, used in the valuation of each asset: Fair Value at Reporting Date Using Quoted Prices in Significant Active Markets for Significant Other Unobservable Identical Assets Observable Inputs Inputs Description Total (Level 1) (Level 2) (Level 3) Recurring Fair Value Measurements Assets: Investment in RMR Inc. (1) $ 95,256 $ 95,256 $ — $ — (1) Our 1,214,225 shares of class A common stock of The RMR Group Inc., or RMR Inc., which are included in other assets in our condensed consolidated balance sheets, are reported at fair value which is based on quoted market prices (Level 1 inputs as defined in the fair value hierarchy under GAAP). Our historical cost basis for these shares is $26,888 as of June 30, 2018 . During the three and six months ended June 30, 2018 , we recorded an unrealized gain of $10,321 and $23,252 , respectively, to adjust our investment in RMR Inc. to its fair value.
Schedule of fair value and carrying value of financial instruments	At June 30, 2018 and December 31, 2017 , the fair values of our financial instruments approximated their carrying values in our condensed consolidated financial statements due to their short term nature or variable interest rates, except as follows: As of June 30, 2018 As of December 31, 2017 Carrying Amount (1) Fair Value Carrying Amount (1) Fair Value Senior unsecured notes, 3.75% interest rate, due in 2019 $ 348,668 $ 351,141 $ 348,096 $ 354,993 Senior unsecured notes, 5.875% interest rate, due in 2046 300,404 316,200 300,232 320,416 Senior unsecured notes, 4.000% interest rate, due in 2022 296,274 297,063 295,812 302,655 Mortgage note payable, 4.050% interest rate, due in 2030 (2) 64,392 63,592 64,293 65,198 Mortgage note payable, 5.720% interest rate, due in 2020 (2) 35,428 35,346 36,085 36,332 Mortgage note payable, 4.220% interest rate, due in 2022 (2) 27,576 27,753 27,906 28,432 Mortgage note payable, 4.800% interest rate, due in 2023 (2) 25,270 25,514 25,501 25,904 Mortgage note payable, 5.877% interest rate, due in 2021 (2) 13,503 14,156 13,620 14,565 Mortgage note payable, 7.000% interest rate, due in 2019 (2) 8,190 8,265 8,391 8,555 Mortgage note payable, 8.150% interest rate, due in 2021 (2) 3,531 3,686 4,111 4,340 Mortgage note payable, 4.260% interest rate, due in 2020 (2) 3,096 3,088 3,193 3,216 $ 1,126,332 $ 1,145,804 $ 1,127,240 $ 1,164,606 (1) Carrying amount includes certain unamortized debt issuance costs and unamortized premiums and discounts. (2) We assumed these mortgages in connection with our acquisitions of the encumbered properties. The stated interest rates for these mortgage debts are the contractually stated rates. We recorded the assumed mortgages at estimated fair value on the date of acquisition and we are amortizing the fair value premiums, if any, to interest expense over the respective terms of the mortgages to reduce interest expense to the estimated market interest rates as of the date of acquisition.

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Schedule of changes in each component of cumulative other comprehensive income (loss)	The following table presents changes in the amounts we recognized in cumulative other comprehensive income by component for the three and six months ended June 30, 2018 : Three Months Ended June 30, 2018 Unrealized Gain Equity in on Investment Unrealized in Equity Gain Securities of Investees Total Balance at March 31, 2018 $ — $ 945 $ 945 Amounts reclassified from cumulative other comprehensive income to cumulative net income — (840 ) (840 ) Other comprehensive income before reclassifications — 70 70 Amounts reclassified from cumulative other comprehensive income to net income (1) — (36 ) (36 ) Net current period other comprehensive income — 34 34 Balance at June 30, 2018 $ — $ 139 $ 139 Six Months Ended June 30, 2018 Unrealized Gain Equity in on Investment Unrealized in Equity Gain (Loss) Securities of Investees Total Balance at December 31, 2017 $ 45,116 $ 15,311 $ 60,427 Amounts reclassified from cumulative other comprehensive income to cumulative net income (45,116 ) (15,165 ) (60,281 ) Other comprehensive income before reclassifications — 48 48 Amounts reclassified from cumulative other comprehensive income to net income (1) — (55 ) (55 ) Net current period other comprehensive loss — (7 ) (7 ) Balance at June 30, 2018 $ — $ 139 $ 139 (1) Amounts reclassified from cumulative other comprehensive loss to net income are included in equity in net earnings of investees in our condensed consolidated statements of comprehensive income.

Equity Investment in Select I26

Equity Investment in Select Income REIT (Tables) - SIR	6 Months Ended
	Jun. 30, 2018
Schedule Of Summarized Balance Sheet Information Of Equity Method Investee	Condensed Consolidated Balance Sheets June 30, December 31, 2018 2017 Real estate properties, net $ 3,919,764 $ 3,905,616 Acquired real estate leases, net 445,616 477,577 Properties held for sale 5,829 5,829 Cash and cash equivalents 31,476 658,719 Rents receivable, net 122,795 127,672 Other assets, net 158,370 127,617 Total assets $ 4,683,850 $ 5,303,030 Unsecured revolving credit facility $ 105,000 $ — Industrial Logistics Properties Trust revolving credit facility 335,000 750,000 Unsecured term loan, net — 348,870 Senior unsecured notes, net 1,429,622 1,777,425 Mortgage notes payable, net 210,715 210,785 Assumed real estate lease obligations, net 64,372 68,783 Other liabilities 143,510 155,348 Total shareholders' equity attributable to SIR 2,077,159 1,991,819 Noncontrolling interest in consolidated subsidiary 318,472 — Total liabilities and shareholders' equity $ 4,683,850 $ 5,303,030
Schedule Of Summarized Income Statement Information Of Equity Method Investee	Condensed Consolidated Statements of Income Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Rental income $ 96,415 $ 97,041 $ 196,170 $ 194,385 Tenant reimbursements and other income 19,592 18,829 40,466 37,779 Total revenues 116,007 115,870 236,636 232,164 Real estate taxes 12,442 10,836 24,230 21,679 Other operating expenses 13,618 13,523 28,900 26,390 Depreciation and amortization 35,009 34,317 69,955 68,057 General and administrative 18,081 8,188 32,022 23,089 Write-off of straight line rents, net 10,626 — 10,626 12,517 Loss on asset impairment — — — 4,047 Loss on impairment of real estate assets — 229 — 229 Total expenses 89,776 67,093 165,733 156,008 Operating income 26,231 48,777 70,903 76,156 Dividend income 396 396 793 793 Unrealized gain on equity securities 13,488 — 30,388 — Interest income 110 7 620 20 Interest expense (22,667 ) (22,808 ) (46,159 ) (43,895 ) Loss on early extinguishment of debt — — (1,192 ) — Income before income tax expense and equity in earnings of an investee 17,558 26,372 55,353 33,074 Income tax expense (101 ) (85 ) (261 ) (187 ) Equity in earnings of an investee 7 374 51 502 Net income 17,464 26,661 55,143 33,389 Net income allocated to noncontrolling interest (5,765 ) — (10,244 ) — Net income attributed to SIR $ 11,699 $ 26,661 $ 44,899 $ 33,389 Weighted average common shares outstanding (basic) 89,393 89,338 89,388 89,334 Weighted average common shares outstanding (diluted) 89,416 89,362 89,398 89,356 Net income attributed to SIR per common share (basic and diluted) $ 0.13 $ 0.30 $ 0.50 $ 0.37

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2018
Segment Reporting [Abstract]
Schedule of Segment Information	Three Months Ended June 30, 2018 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 108,085 $ — $ — $ 108,085 Expenses: Real estate taxes 12,365 — — 12,365 Utility expenses 6,018 — — 6,018 Other operating expenses 21,599 — — 21,599 Depreciation and amortization 42,671 — — 42,671 Loss on impairment of real estate (316 ) — — (316 ) General and administrative — — 4,449 4,449 Total expenses 82,337 — 4,449 86,786 Operating income (loss) 25,748 — (4,449 ) 21,299 Dividend income — — 304 304 Unrealized gain on equity securities — — 10,321 10,321 Interest income 56 — 93 149 Interest expense (2,014 ) — (21,290 ) (23,304 ) Net gain on issuance of shares by Select Income REIT — 8 — 8 Income (loss) from continuing operations before income tax, equity in net earnings (losses) of investees and gain on sale of real estate 23,790 8 (15,021 ) 8,777 Income tax expense — — (83 ) (83 ) Equity in net earnings (losses) of investees (636 ) 4,301 7 3,672 Income (loss) from continuing operations before gain on sale of real estate 23,154 4,309 (15,097 ) 12,366 Gain on sale of real estate 17,329 — — 17,329 Net income (loss) $ 40,483 $ 4,309 $ (15,097 ) $ 29,695 Preferred units of limited partnership distributions — — (93 ) (93 ) Net income (loss) available for common shareholders $ 40,483 $ 4,309 $ (15,190 ) $ 29,602 Six Months Ended June 30, 2018 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 216,802 $ — $ — $ 216,802 Expenses: Real estate taxes 25,330 — — 25,330 Utility expenses 12,707 — — 12,707 Other operating expenses 44,436 — — 44,436 Depreciation and amortization 86,875 — — 86,875 Loss on impairment of real estate 5,800 — — 5,800 General and administrative — — 14,055 14,055 Total expenses 175,148 — 14,055 189,203 Operating income (loss) 41,654 — (14,055 ) 27,599 Dividend income — — 608 608 Unrealized gain on equity securities — — 23,252 23,252 Interest income 113 — 152 265 Interest expense (4,109 ) — (41,961 ) (46,070 ) Net gain on issuance of shares by Select Income REIT — 8 — 8 Income (loss) from continuing operations before income taxes, equity in net earnings (losses) of investees and gain on sale of real estate 37,658 8 (32,004 ) 5,662 Income tax expense — — (115 ) (115 ) Equity in net earnings (losses) of investees (1,257 ) 14,590 51 13,384 Income (loss) from continuing operations before gain on sale of real estate 36,401 14,598 (32,068 ) 18,931 Gain on sale of real estate 17,329 — — 17,329 Net income (loss) 53,730 14,598 (32,068 ) 36,260 Preferred units of limited partnership distributions — — (371 ) (371 ) Net income (loss) available for common shareholders $ 53,730 $ 14,598 $ (32,439 ) $ 35,889 As of June 30, 2018 Investment Investment in Real Estate in SIR Corporate Consolidated Total Assets $ 2,927,745 $ 456,756 $ 123,268 $ 3,507,769 Three Months Ended June 30, 2017 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 69,887 $ — $ — $ 69,887 Expenses: Real estate taxes 7,941 — — 7,941 Utility expenses 4,172 — — 4,172 Other operating expenses 15,187 — — 15,187 Depreciation and amortization 20,663 — — 20,663 General and administrative — — 5,087 5,087 Total expenses 47,963 — 5,087 53,050 Operating income (loss) 21,924 — (5,087 ) 16,837 Dividend income — — 304 304 Interest income 48 — 19 67 Interest expense (405 ) — (13,558 ) (13,963 ) Net gain on issuance of shares by Select Income REIT — 21 — 21 Income (loss) from continuing operations before income taxes and equity in net earnings of investee 21,567 21 (18,322 ) 3,266 Income tax expense — — (25 ) (25 ) Equity in net earnings of investees — 8,207 374 8,581 Income (loss) from continuing operations 21,567 8,228 (17,973 ) 11,822 Loss from discontinued operations (145 ) — — (145 ) Net income (loss) available for common shareholders $ 21,422 $ 8,228 $ (17,973 ) $ 11,677 Six Months Ended June 30, 2017 Investment Investment in Real Estate in SIR Corporate Consolidated Rental income $ 139,183 $ — $ — $ 139,183 Expenses: Real estate taxes 16,118 — — 16,118 Utility expenses 8,778 — — 8,778 Other operating expenses 29,179 — — 29,179 Depreciation and amortization 41,168 — — 41,168 General and administrative — — 9,049 9,049 Total expenses 95,243 — 9,049 104,292 Operating income (loss) 43,940 — (9,049 ) 34,891 Dividend income — — 608 608 Interest income 94 — 34 128 Interest expense (837 ) — (26,707 ) (27,544 ) Net gain on issuance of shares by Select Income REIT — 21 — 21 Income (loss) from continuing operations before income taxes and equity in net earnings of investee 43,197 21 (35,114 ) 8,104 Income tax expense — — (43 ) (43 ) Equity in net earnings of investees — 10,818 502 11,320 Income (loss) from continuing operations 43,197 10,839 (34,655 ) 19,381 Loss from discontinued operations (289 ) — — (289 ) Net income (loss) available for common shareholders $ 42,908 $ 10,839 $ (34,655 ) $ 19,092 As of December 31, 2017 Investment Investment in Real Estate in SIR Corporate Consolidated Total Assets $ 3,138,764 $ 467,499 $ 97,302 $ 3,703,565

Recent Accounting Pronounceme28

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred gain on sale of real estate					$ 712
Unrealized gain on investment in equity securities	$ 0	$ (1,032)	$ 0	$ 11,110
Equity in net earnings of investees	3,672	8,581	13,384	11,320
Increase in cash provided by operating activities			93,497	69,802
Restricted cash	$ 2,448	$ 344	2,448	344	3,111
ASU 2016-01 | Other Comprehensive Income (Loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unrealized gain on investment in equity securities					45,116
ASU 2016-15
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accretion in equity of earnings			$ (1,472)
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in cash provided by operating activities				$ 186
SIR and AIC | ASU 2016-01 | Other Comprehensive Income (Loss)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Equity in net earnings of investees					$ 15,165

Weighted Average Common Share29

Weighted Average Common Shares (Details) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Basic and Diluted [Abstract]
Weighted average common shares for basic earnings per share (in shares)	99,051	71,088	99,046	71,083
Effect of dilutive securities: unvested share awards (in shares)	13	31	4	26
Weighted average common shares for diluted earnings per share (in shares)	99,064	71,119	99,050	71,109

Real Estate Properties - Additi

Real Estate Properties - Additional Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018USD ($)ft²leasebuildingproperty	Jun. 30, 2018USD ($)ft²leasebuildingjoint_ventureproperty
Real Estate Properties [Line Items]
Number of properties owned | property	105	105
Number of buildings | building	164	164
Number of joint ventures | joint_venture		2
Number of properties, noncontrolling interest | property		2
Number of buildings, noncontrolling interest | building		3
Number of leases entered | lease	37	70
Rentable square feet (in sqft) | ft²	396,359	676,778
Weighted average lease term	6 years 2 months 12 days	5 years 10 months 24 days
Expenditures committed on leases | $	$ 6,810	$ 14,808
Committed but unspent tenant related obligations estimated | $	$ 32,609	$ 32,609
Continuing operations
Real Estate Properties [Line Items]
Number of properties owned | property	105	105
Number of buildings | building	164	164
Carry value of properties | $	$ 2,845,449	$ 2,845,449

Real Estate Properties - Dispos

Real Estate Properties - Disposition Activities (Details) $ in Thousands	1 Months Ended		3 Months Ended			6 Months Ended
	May 31, 2018USD ($)ft²buildingproperty	Mar. 31, 2018USD ($)ft²building	Jun. 30, 2018USD ($)buildingproperty	Mar. 31, 2018USD ($)ft²building	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)buildingproperty	Jun. 30, 2017USD ($)	Feb. 28, 2018ft²buildingproperty	Dec. 31, 2017USD ($)
Real Estate Properties [Line Items]
Number of properties | property			105			105
Number of buildings | building			164			164
Loss on impairment of real estate			$ 316		$ 0	$ (5,800)	$ 0
Gain (loss) on sale of real estate			17,329		$ 0	17,329	$ 0
Net book value			$ 2,487,163			$ 2,487,163			$ 2,633,873
Office Building | Disposal Group, Disposed of by Sale | Minneapolis, NM | One building
Real Estate Properties [Line Items]
Number of properties | property			1			1
Number of buildings | building		1		1
Rentable area of properties (in square feet) | ft²		193,594		193,594
Aggregate sale price of properties sold, excluding closing costs		$ 20,000
Loss on impairment of real estate						$ (640)
Office Building | Disposal Group, Disposed of by Sale | Safford, AZ | One building
Real Estate Properties [Line Items]
Number of properties | property								1
Number of buildings | building								1
Rentable area of properties (in square feet) | ft²								36,139
Aggregate sale price of properties sold, excluding closing costs				$ 8,250
Loss on impairment of real estate				(2,453)
Fair value adjustment				322
Office Building | Disposal Group, Disposed of by Sale | New York, NY | One building
Real Estate Properties [Line Items]
Number of properties | property	1
Number of buildings | building	1
Rentable area of properties (in square feet) | ft²	187,060
Aggregate sale price of properties sold, excluding closing costs	$ 118,500
Gain (loss) on sale of real estate			$ (17,329)
Office Building | Disposal Group, Disposed of by Sale | Sacramento, CA | One building
Real Estate Properties [Line Items]
Number of properties | property	1
Number of buildings | building	1
Rentable area of properties (in square feet) | ft²	110,500
Aggregate sale price of properties sold, excluding closing costs	$ 10,755
Loss on impairment of real estate			$ 6	$ 3,023
FPO Transaction | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties | property			24			24
Number of buildings | building			56			56
Net book value			$ 506,741			$ 506,741

Real Estate Properties - FPO Tr

Real Estate Properties - FPO Transaction (Details) $ in Thousands	Oct. 02, 2017USD ($)ft²buildingjoint_ventureproperty	Jun. 30, 2018buildingjoint_ventureproperty
Business Acquisition [Line Items]
Number of joint ventures | joint_venture		2
Number of properties owned | property		105
Number of buildings | building		164
First Potomac Realty Trust
Business Acquisition [Line Items]
Number of properties acquired | property	35
Number of buildings acquired | building	72
Rentable area of properties (in square feet) | ft²	6,028,072
Purchase price | $	$ 1,370,888
First Potomac Realty Trust
Business Acquisition [Line Items]
Number of joint ventures | joint_venture	2
Number of properties owned | property	2
Number of buildings | building	3
First Potomac Realty Trust | First Potomac Realty Trust
Business Acquisition [Line Items]
Rentable area of properties (in square feet) | ft²	443,867
Joint Venture Property 1 | First Potomac Realty Trust
Business Acquisition [Line Items]
Percentage of ownership interest	50.00%
Joint Venture Property 2 | First Potomac Realty Trust
Business Acquisition [Line Items]
Percentage of ownership interest	51.00%

Real Estate Properties - Pro Fo

Real Estate Properties - Pro Forma (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)$ / shares
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Rental income	$ 219,784
Net loss	$ (1,613)
Net loss per share (in dollars per share) | $ / shares	$ 0.02
Acquisition-related costs
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Decrease in revenues	$ 804
Decrease in net income	$ 46,881

Real Estate Properties - Schedu

Real Estate Properties - Schedule of Joint Ventures (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)ft²buildingjoint_ventureproperty	Dec. 31, 2017USD ($)
Real Estate [Line Items]
Number of joint ventures | joint_venture	2
Number of properties owned | property	105
Investment at carrying value	$ 456,756	$ 467,499
Number of buildings | building	164
Unconsolidated Joint Ventures
Real Estate [Line Items]
Investment at carrying value	$ 46,712
Number of buildings | building	3
Square Feet (in square feet) | ft²	443,867
Interest rate (as a percent)	3.9339%
Principal Balance	$ 82,000
Unamortized basis difference	$ 8,688
Unconsolidated Joint Ventures | Prosperity Metro Plaza
Real Estate [Line Items]
GOV Ownership	51.00%
Investment at carrying value	$ 25,669
Number of buildings | building	2
Square Feet (in square feet) | ft²	328,456
Interest rate (as a percent)	4.09%
Principal Balance	$ 50,000
Unconsolidated Joint Ventures | 1750 H Street, NW
Real Estate [Line Items]
GOV Ownership	50.00%
Investment at carrying value	$ 21,043
Number of buildings | building	1
Square Feet (in square feet) | ft²	115,411
Interest rate (as a percent)	3.69%
Principal Balance	$ 32,000

Revenue Recognition (Details)

Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Revenue Recognition [Abstract]
Increase in rental income to record revenue on straight line basis	$ 2,744	$ 1,104	$ 5,835	$ 2,404
Straight line rent receivables	32,001		32,001		$ 27,267
Allowance for doubtful accounts	$ 1,426		$ 1,426		$ 1,503

Concentration (Details)

Concentration (Details)	6 Months Ended
	Jun. 30, 2018buildinggovernment_tenantstate_governmentstateproperty	Jun. 30, 2017
Concentration
Number of state governments | state_government	13
Number of other governments | government_tenant	3
Number of properties | property	105
Number of buildings | building	164
Number of states in which acquired properties located | state	30
Annualized rental income, excluding properties classified as discontinued operations | Virginia
Concentration
Annualized Rental income percent	24.00%
Annualized rental income, excluding properties classified as discontinued operations | District of Columbia
Concentration
Annualized Rental income percent	18.10%
Annualized rental income, excluding properties classified as discontinued operations | Maryland
Concentration
Annualized Rental income percent	15.50%
Annualized rental income, excluding properties classified as discontinued operations | California
Concentration
Annualized Rental income percent	9.40%
Annualized rental income, excluding properties classified as discontinued operations | Georgia
Concentration
Annualized Rental income percent	6.10%
Annualized rental income, excluding properties classified as discontinued operations | Washington, DC Market Area
Concentration
Concentration risk percentage	44.60%
Annualized rental income, excluding properties classified as discontinued operations | Tenant concentration | U.S. Government, state governments and Other Four Government
Concentration
Concentration risk percentage	61.90%	87.60%
Annualized rental income, excluding properties classified as discontinued operations | Tenant concentration | U.S. Government
Concentration
Concentration risk percentage	45.20%	59.60%

Indebtedness - Debt Obligations

Indebtedness - Debt Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jul. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Borrowings outstanding	$ 452,000		$ 452,000			$ 570,000
Maximum borrowing capacity on revolving credit facility	2,500,000		2,500,000
Aggregate principal amount on secured properties	181,339		181,339
Debt outstanding	548,192		548,192			$ 547,852
Unsecured term loan, due in 2020
Debt Instrument [Line Items]
Face amount	$ 300,000		$ 300,000
Interest rate (as a percent)	3.50%		3.50%
The weighted average annual interest rate (as a percent)	3.30%	2.40%	3.20%	2.30%
Unsecured term loan, due in 2022
Debt Instrument [Line Items]
Face amount	$ 250,000		$ 250,000
Interest rate (as a percent)	3.90%		3.90%
The weighted average annual interest rate (as a percent)	3.70%	2.80%	3.60%	2.70%
Unsecured revolving credit facility
Debt Instrument [Line Items]
Borrowings outstanding	$ 452,000		$ 452,000
Maximum borrowing capacity on revolving credit facility	$ 750,000		$ 750,000
Option to extend the maturity date subject to certain conditions and the payment of a fee			1 year
Facility fee (as a percent)			0.25%
Interest rate (as a percent)	3.20%		3.20%
The weighted average annual interest rate (as a percent)	3.00%	2.20%	2.90%	2.10%
Unsecured revolving credit facility | Subsequent Event
Debt Instrument [Line Items]
Debt outstanding					$ 452,000
Term loans
Debt Instrument [Line Items]
Face amount	$ 550,000		$ 550,000
Senior unsecured notes
Debt Instrument [Line Items]
Face amount	$ 960,000		$ 960,000
LIBOR | Unsecured term loan, due in 2020
Debt Instrument [Line Items]
Interest rate premium (as a percent)			1.40%
LIBOR | Unsecured term loan, due in 2022
Debt Instrument [Line Items]
Interest rate premium (as a percent)			1.80%
LIBOR | Unsecured revolving credit facility
Debt Instrument [Line Items]
Interest rate premium (as a percent)			1.25%

Indebtedness - Additional Infor

Indebtedness - Additional Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018USD ($)buildingloanproperty
Debt Disclosure [Abstract]
Number of properties secured by mortgage notes | property	8
Number of buildings secured by mortgage notes | building	8
Aggregate net book value of secured properties	$ 422,583
Number of assumed secured mortgage loans | loan	8
Aggregate principal amount on secured properties	$ 181,339

Fair Value of Assets and Liab39

Fair Value of Assets and Liabilities - Recurring and Nonrecurring Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Fair Value of Assets and Liabilities
Common shares owned in RMR Inc. (in shares)	1,214,225		1,214,225
Historical cost	$ 26,888		$ 26,888
Unrealized gain on equity securities	10,321	$ 0	23,252	$ 0
Recurring
Fair Value of Assets and Liabilities
Investment in RMR Inc.	95,256		95,256
Recurring | Level 1 inputs
Fair Value of Assets and Liabilities
Investment in RMR Inc.	95,256		95,256
Recurring | Level 2 inputs
Fair Value of Assets and Liabilities
Investment in RMR Inc.	0		0
Recurring | Level 3 inputs
Fair Value of Assets and Liabilities
Investment in RMR Inc.	$ 0		$ 0

Fair Value of Assets and Liab40

Fair Value of Assets and Liabilities - Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Fair Value of Financial Instruments
Senior Notes	$ 945,346	$ 944,140
Mortgage notes payable, net	$ 180,986	183,100
Senior unsecured notes, 3.75% interest rate, due in 2019
Fair Value of Financial Instruments
Interest rate (as a percent)	3.75%
Senior unsecured notes, 5.875% interest rate, due in 2046
Fair Value of Financial Instruments
Interest rate (as a percent)	5.875%
Senior unsecured notes, 4.000% interest rate, due in 2022
Fair Value of Financial Instruments
Interest rate (as a percent)	4.00%
Mortgage note payable, 4.050% interest rate, due in 2030
Fair Value of Financial Instruments
Interest rate (as a percent)	4.05%
Mortgage note payable, 5.720% interest rate, due in 2020
Fair Value of Financial Instruments
Interest rate (as a percent)	5.72%
Mortgage note payable, 4.220% interest rate, due in 2022
Fair Value of Financial Instruments
Interest rate (as a percent)	4.22%
Mortgage note payable, 4.800% interest rate, due in 2023
Fair Value of Financial Instruments
Interest rate (as a percent)	4.80%
Mortgage note payable, 5.877% interest rate, due in 2021
Fair Value of Financial Instruments
Interest rate (as a percent)	5.877%
Mortgage note payable, 7.000% interest rate, due in 2019
Fair Value of Financial Instruments
Interest rate (as a percent)	7.00%
Mortgage note payable, 8.150% interest rate, due in 2021
Fair Value of Financial Instruments
Interest rate (as a percent)	8.15%
Mortgage note payable, 4.260% interest rate, due in 2020
Fair Value of Financial Instruments
Interest rate (as a percent)	4.26%
Carrying Amount
Fair Value of Financial Instruments
Fair value of financial instruments	$ 1,126,332	1,127,240
Carrying Amount | Senior unsecured notes, 3.75% interest rate, due in 2019
Fair Value of Financial Instruments
Senior Notes	348,668	348,096
Carrying Amount | Senior unsecured notes, 5.875% interest rate, due in 2046
Fair Value of Financial Instruments
Senior Notes	300,404	300,232
Carrying Amount | Senior unsecured notes, 4.000% interest rate, due in 2022
Fair Value of Financial Instruments
Senior Notes	296,274	295,812
Carrying Amount | Mortgage note payable, 4.050% interest rate, due in 2030
Fair Value of Financial Instruments
Mortgage notes payable, net	64,392	64,293
Carrying Amount | Mortgage note payable, 5.720% interest rate, due in 2020
Fair Value of Financial Instruments
Mortgage notes payable, net	35,428	36,085
Carrying Amount | Mortgage note payable, 4.220% interest rate, due in 2022
Fair Value of Financial Instruments
Mortgage notes payable, net	27,576	27,906
Carrying Amount | Mortgage note payable, 4.800% interest rate, due in 2023
Fair Value of Financial Instruments
Mortgage notes payable, net	25,270	25,501
Carrying Amount | Mortgage note payable, 5.877% interest rate, due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net	13,503	13,620
Carrying Amount | Mortgage note payable, 7.000% interest rate, due in 2019
Fair Value of Financial Instruments
Mortgage notes payable, net	8,190	8,391
Carrying Amount | Mortgage note payable, 8.150% interest rate, due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net	3,531	4,111
Carrying Amount | Mortgage note payable, 4.260% interest rate, due in 2020
Fair Value of Financial Instruments
Mortgage notes payable, net	3,096	3,193
Fair Value
Fair Value of Financial Instruments
Fair value of financial instruments	1,145,804	1,164,606
Fair Value | Senior unsecured notes, 3.75% interest rate, due in 2019
Fair Value of Financial Instruments
Senior Notes	351,141	354,993
Fair Value | Senior unsecured notes, 5.875% interest rate, due in 2046
Fair Value of Financial Instruments
Senior Notes	316,200	320,416
Fair Value | Senior unsecured notes, 4.000% interest rate, due in 2022
Fair Value of Financial Instruments
Senior Notes	297,063	302,655
Fair Value | Mortgage note payable, 4.050% interest rate, due in 2030
Fair Value of Financial Instruments
Mortgage notes payable, net	63,592	65,198
Fair Value | Mortgage note payable, 5.720% interest rate, due in 2020
Fair Value of Financial Instruments
Mortgage notes payable, net	35,346	36,332
Fair Value | Mortgage note payable, 4.220% interest rate, due in 2022
Fair Value of Financial Instruments
Mortgage notes payable, net	27,753	28,432
Fair Value | Mortgage note payable, 4.800% interest rate, due in 2023
Fair Value of Financial Instruments
Mortgage notes payable, net	25,514	25,904
Fair Value | Mortgage note payable, 5.877% interest rate, due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net	14,156	14,565
Fair Value | Mortgage note payable, 7.000% interest rate, due in 2019
Fair Value of Financial Instruments
Mortgage notes payable, net	8,265	8,555
Fair Value | Mortgage note payable, 8.150% interest rate, due in 2021
Fair Value of Financial Instruments
Mortgage notes payable, net	3,686	4,340
Fair Value | Mortgage note payable, 4.260% interest rate, due in 2020
Fair Value of Financial Instruments
Mortgage notes payable, net	$ 3,088	$ 3,216

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Details) $ / shares in Units, $ in Thousands	Jul. 19, 2018USD ($)$ / shares	May 24, 2018trustee$ / sharesshares	May 21, 2018USD ($)$ / shares	Apr. 03, 2018$ / sharesshares	Feb. 26, 2018USD ($)$ / shares	Jan. 01, 2018$ / sharesshares	Jun. 30, 2018	May 01, 2018USD ($)$ / sharesshares
Share Awards
Cash distribution to common shareholders (in dollars per share)					$ 0.43
Distribution paid to common shareholders | $			$ 42,634		$ 42,632
Distribution payable to common shareholders (in dollars per share)			$ 0.43
Subsequent Event
Share Awards
Dividends declared (in dollars per share)	$ 0.43
Dividends declared | $	$ 42,641
Former Employee of RMR LLC
Share Awards
Stock repurchased (in shares) | shares						617
Stock repurchased (in dollars per share)						$ 18.54
Trustees
Share Awards
Number of trustees | trustee		1
Stock repurchased (in shares) | shares		450
Stock repurchased (in dollars per share)		$ 14.10
Share Award Plan | Common shares | Trustees
Share Awards
Shares granted (in dollars per share)		$ 14.10		$ 13.59
Number of trustees | trustee		6
Shares granted (in shares) | shares		3,000		3,000
Series A Cumulative Preferred Units
Share Awards
Temporary equity (in shares) | shares								1,813,504
Redemption percentage							5.50%
Redemption price (in dollars per share)								$ 11.15
Redemption amount | $								$ 20,310

Shareholders' Equity - AOCI Rol

Shareholders' Equity - AOCI Roll Forward (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			$ 1,330,043
Other comprehensive income (loss)	$ 34	$ (1,364)	(7)	$ 15,393
Ending balance	1,281,650		1,281,650
Unrealized Gain on Investment in Equity Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	0		45,116
Amounts reclassified from cumulative other comprehensive income to cumulative net income	0		(45,116)
Other comprehensive income before reclassifications	0		0
Amounts reclassified from cumulative other comprehensive loss to net income	0		0
Other comprehensive income (loss)	0		0
Ending balance	0		0
Equity in Unrealized Gain (Loss) of an Investee
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	945		15,311
Amounts reclassified from cumulative other comprehensive income to cumulative net income	(840)		(15,165)
Other comprehensive income before reclassifications	70		48
Amounts reclassified from cumulative other comprehensive loss to net income	(36)		(55)
Other comprehensive income (loss)	34		(7)
Ending balance	139		139
Total
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	945		60,427
Amounts reclassified from cumulative other comprehensive income to cumulative net income	(840)		(60,281)
Other comprehensive income before reclassifications	70		48
Amounts reclassified from cumulative other comprehensive loss to net income	(36)		(55)
Other comprehensive income (loss)	34		(7)
Ending balance	$ 139		$ 139

Business and Property Managem43

Business and Property Management Agreements with RMR LLC (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)employeeagreement	Jun. 30, 2017USD ($)
RMR LLC
Related Party Transaction [Line Items]
Number of employees | employee			0
Number of agreements | agreement			2
Related party expense	$ 2,175	$ 3,646	$ 9,484	$ 6,350
Reimbursement expense	5,052	3,655	10,021	7,046
Internal audit costs	54	67	123	135
Net Property Management and Construction Supervision Fees | RMR LLC
Related Party Transaction [Line Items]
Related party transaction amount	3,437	2,567	6,786	5,033
RMR LLC | Affiliated Entity
Related Party Transaction [Line Items]
Reversal of expense with related party	$ (2,150)	$ 893	$ 737	$ 893
Period of common share total return, incentive fees payable	3 years

Related Person Transactions - R

Related Person Transactions - REITs, for which RMR LLC provides Management Services (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)company	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)agreementcompanyshares	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
SIR
Related Party Transaction [Line Items]
Shares holding (in shares) | shares			24,918,421
Percentage of outstanding shares owned	27.80%		27.80%
RMR Inc | Class A common shares
Related Party Transaction [Line Items]
Shares holding (in shares) | shares			1,214,225
RMR LLC
Related Party Transaction [Line Items]
Number of agreements | agreement			2
Revenue from related party	$ 282	$ 90	$ 500	$ 182
Property insurance premiums paid	$ 2,175	$ 3,646	$ 9,484	$ 6,350
AIC
Related Party Transaction [Line Items]
Number of entities to whom services are provided | company	4		4
Carrying value of equity method investments	$ 8,272		$ 8,272		$ 8,304
Property Insurance Premium Expense
Related Party Transaction [Line Items]
Property insurance premiums paid			$ 1,211

Equity Investment in Select I45

Equity Investment in Select Income REIT - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Equity in net earnings of investees	$ 3,672	$ 8,581	$ 13,384	$ 11,320
Investment at carrying value	$ 456,756		456,756		$ 467,499
Cash distributions from SIR			$ 14,590	10,817
SIR
Schedule of Equity Method Investments [Line Items]
Equity investments, common shares owned (in shares)	24,918,421		24,918,421
Percentage of outstanding shares owned	27.80%		27.80%
Equity in net earnings of investees	$ 4,301	8,207	$ 14,590	10,818
Equity in unrealized gain (loss) of investees	24	(389)	75	4,103
The amount of investment in exceed the underlying equity of the investee	121,535		121,535		$ 87,137
Accretion in equity of earnings	1,044	736	2,088	1,472
Investment at carrying value	456,756		456,756
Equity Investments, market value	559,917		559,917
Cash distributions from SIR	$ 12,708	$ 12,708	$ 25,417	$ 25,416

Equity Investment in Select I46

Equity Investment in Select Income REIT - Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Schedule of Equity Method Investments [Line Items]
Real estate properties, net	$ 2,487,163	$ 2,633,873
Acquired real estate leases, net	297,696	351,872
Cash and cash equivalents	18,695	16,569	$ 12,907
Rents receivable, net	61,522	61,429
Other assets, net	113,877	96,033
Total assets	3,507,769	3,703,565
Unsecured revolving credit facility	452,000	570,000
Unsecured term loan, net	548,192	547,852
Senior unsecured notes, net	945,346	944,140
Mortgage notes payable, net	180,986	183,100
Assumed real estate lease obligations, net	11,738	13,635
Other liabilities	80,728	89,440
Total shareholders' equity attributable to SIR	1,281,650	1,330,043
Total liabilities and shareholders’ equity	3,507,769	3,703,565
SIR | SIR
Schedule of Equity Method Investments [Line Items]
Real estate properties, net	3,919,764	3,905,616
Acquired real estate leases, net	445,616	477,577
Properties held for sale	5,829	5,829
Cash and cash equivalents	31,476	658,719
Rents receivable, net	122,795	127,672
Other assets, net	158,370	127,617
Total assets	4,683,850	5,303,030
Unsecured revolving credit facility	105,000	0
Industrial Logistics Properties Trust revolving credit facility	335,000	750,000
Unsecured term loan, net	0	348,870
Senior unsecured notes, net	1,429,622	1,777,425
Mortgage notes payable, net	210,715	210,785
Assumed real estate lease obligations, net	64,372	68,783
Other liabilities	143,510	155,348
Total shareholders' equity attributable to SIR	2,077,159	1,991,819
Noncontrolling interest in consolidated subsidiary	318,472	0
Total liabilities and shareholders’ equity	$ 4,683,850	$ 5,303,030

Equity Investment in Select I47

Equity Investment in Select Income REIT - Income Statement Information (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Schedule of Equity Method Investments [Line Items]
Rental income	$ 108,085	$ 69,887	$ 216,802	$ 139,183
Real estate taxes	12,365	7,941	25,330	16,118
Other operating expenses	21,599	15,187	44,436	29,179
Depreciation and amortization	42,671	20,663	86,875	41,168
General and administrative	4,449	5,087	14,055	9,049
Loss on impairment of real estate assets	(316)	0	5,800	0
Total expenses	86,786	53,050	189,203	104,292
Operating income	21,299	16,837	27,599	34,891
Dividend income	304	304	608	608
Unrealized gain on equity securities	10,321	0	23,252	0
Interest income	149	67	265	128
Interest expense	(23,304)	(13,963)	(46,070)	(27,544)
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	8,777	3,266	5,662	8,104
Income tax expense	(83)	(25)	(115)	(43)
Equity in earnings of an investee	3,672	8,581	13,384	11,320
Net income attributed to SIR	$ 29,695	$ 11,677	$ 36,260	$ 19,092
Weighted average common shares outstanding (basic) (in shares)	99,051	71,088	99,046	71,083
Weighted average common shares outstanding (diluted) (in shares)	99,064	71,119	99,050	71,109
Net income attributed to SIR per common share (basic and diluted) (in dollars per share)	$ 0.30	$ 0.16	$ 0.36	$ 0.27
SIR
Schedule of Equity Method Investments [Line Items]
Equity in earnings of an investee	$ 4,301	$ 8,207	$ 14,590	$ 10,818
SIR | SIR
Schedule of Equity Method Investments [Line Items]
Rental income	96,415	97,041	196,170	194,385
Tenant reimbursements and other income	19,592	18,829	40,466	37,779
Total revenues	116,007	115,870	236,636	232,164
Real estate taxes	12,442	10,836	24,230	21,679
Other operating expenses	13,618	13,523	28,900	26,390
Depreciation and amortization	35,009	34,317	69,955	68,057
General and administrative	18,081	8,188	32,022	23,089
Write-off of straight line rents, net	10,626	0	10,626	12,517
Loss on asset impairment	0	0	0	4,047
Loss on impairment of real estate assets	0	229	0	229
Total expenses	89,776	67,093	165,733	156,008
Operating income	26,231	48,777	70,903	76,156
Dividend income	396	396	793	793
Unrealized gain on equity securities	13,488	0	30,388	0
Interest income	110	7	620	20
Interest expense	(22,667)	(22,808)	(46,159)	(43,895)
Loss on early extinguishment of debt	0	0	(1,192)	0
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	17,558	26,372	55,353	33,074
Income tax expense	(101)	(85)	(261)	(187)
Equity in earnings of an investee	7	374	51	502
Net income	17,464	26,661	55,143	33,389
Net income allocated to noncontrolling interest	(5,765)	0	(10,244)	0
Net income attributed to SIR	$ 11,699	$ 26,661	$ 44,899	$ 33,389
Weighted average common shares outstanding (basic) (in shares)	89,393	89,338	89,388	89,334
Weighted average common shares outstanding (diluted) (in shares)	89,416	89,362	89,398	89,356
Net income attributed to SIR per common share (basic and diluted) (in dollars per share)	$ 0.13	$ 0.30	$ 0.50	$ 0.37

Segment Information (Details)

Segment Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)segment	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Segment Reporting Information [Line Items]
Number of segments | segment			2
Expenses:
Real estate taxes	$ 12,365	$ 7,941	$ 25,330	$ 16,118
Other operating expenses	21,599	15,187	44,436	29,179
Depreciation and amortization	42,671	20,663	86,875	41,168
Loss on impairment of real estate	(316)	0	5,800	0
General and administrative	4,449	5,087	14,055	9,049
Total expenses	86,786	53,050	189,203	104,292
Operating income	21,299	16,837	27,599	34,891
Dividend income	304	304	608	608
Unrealized gain on equity securities	10,321	0	23,252	0
Interest income	149	67	265	128
Interest expense	(23,304)	(13,963)	(46,070)	(27,544)
Net gain on issuance of shares by Select Income REIT	8	21	8	21
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	8,777	3,266	5,662	8,104
Income tax expense	(83)	(25)	(115)	(43)
Equity in net earnings (losses) of investees	3,672	8,581	13,384	11,320
Income from continuing operations	12,366	11,822	18,931	19,381
Loss from discontinued operations	0	(145)	0	(289)
Gain on sale of real estate	17,329	0	17,329	0
Net income (loss)	29,695	11,677	36,260	19,092
Preferred units of limited partnership distributions	(93)	0	(371)	0
Net income available for common shareholders	29,602	11,677	35,889	19,092
Total assets	3,507,769		3,507,769		$ 3,703,565
Operating Segments | Investment in Real Estate
Expenses:
Real estate taxes	12,365	7,941	25,330	16,118
Other operating expenses	21,599	15,187	44,436	29,179
Depreciation and amortization	42,671	20,663	86,875	41,168
Loss on impairment of real estate	(316)		5,800
Total expenses	82,337	47,963	175,148	95,243
Operating income	25,748	21,924	41,654	43,940
Interest income	56	48	113	94
Interest expense	(2,014)	(405)	(4,109)	(837)
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	23,790	21,567	37,658	43,197
Equity in net earnings (losses) of investees	(636)		(1,257)
Income from continuing operations	23,154	21,567	36,401	43,197
Loss from discontinued operations		(145)		(289)
Gain on sale of real estate	17,329		17,329
Net income (loss)	40,483		53,730
Net income available for common shareholders	40,483	21,422	53,730	42,908
Total assets	2,927,745		2,927,745		3,138,764
Operating Segments | Investment in SIR
Expenses:
Net gain on issuance of shares by Select Income REIT	8	21	8	21
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	8	21	8	21
Equity in net earnings (losses) of investees	4,301	8,207	14,590	10,818
Income from continuing operations	4,309	8,228	14,598	10,839
Net income (loss)	4,309		14,598
Net income available for common shareholders	4,309	8,228	14,598	10,839
Total assets	456,756		456,756		467,499
Corporate, Non-Segment
Expenses:
General and administrative	4,449	5,087	14,055	9,049
Total expenses	4,449	5,087	14,055	9,049
Operating income	(4,449)	(5,087)	(14,055)	(9,049)
Dividend income	304	304	608	608
Unrealized gain on equity securities	10,321		23,252
Interest income	93	19	152	34
Interest expense	(21,290)	(13,558)	(41,961)	(26,707)
Income from continuing operations before income taxes, equity in net earnings of investees and net gain on sale of real estate	(15,021)	(18,322)	(32,004)	(35,114)
Income tax expense	(83)	(25)	(115)	(43)
Equity in net earnings (losses) of investees	7	374	51	502
Income from continuing operations	(15,097)	(17,973)	(32,068)	(34,655)
Net income (loss)	(15,097)		(32,068)
Preferred units of limited partnership distributions	(93)		(371)
Net income available for common shareholders	(15,190)	(17,973)	(32,439)	(34,655)
Total assets	123,268		123,268		$ 97,302
Rental income
Segment Reporting Information [Line Items]
Rental income	108,085	69,887	216,802	139,183
Rental income | Operating Segments | Investment in Real Estate
Segment Reporting Information [Line Items]
Rental income	108,085	69,887	216,802	139,183
Utility expenses
Expenses:
Utility expenses	6,018	4,172	12,707	8,778
Utility expenses | Operating Segments | Investment in Real Estate
Expenses:
Utility expenses	$ 6,018	$ 4,172	$ 12,707	$ 8,778