Office Properties Income Trust (OPI) 10-Q 30 Oct 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 29, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	1-34364
Entity Registrant Name	OFFICE PROPERTIES INCOME TRUST
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	26-4273474
Entity Address, Address Line One	Two Newton Place
Entity Address, Address Line Two	255 Washington Street
Entity Address, Address Line Three	Suite 300
Entity Address, City or Town	Newton
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02458-1634
City Area Code	617
Local Phone Number	219-1440
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		48,318,366
Entity Central Index Key	0001456772
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Common Shares of Beneficial Interest
Entity Information [Line Items]
Title of 12(b) Security	Common Shares of Beneficial Interest
Trading Symbol	OPI
Security Exchange Name	NASDAQ
5.875% Senior Notes due 2046
Entity Information [Line Items]
Title of 12(b) Security	5.875% Senior Notes due 2046
Trading Symbol	OPINI
Security Exchange Name	NASDAQ
6.375% Senior Notes due 2050
Entity Information [Line Items]
Title of 12(b) Security	6.375% Senior Notes due 2050
Trading Symbol	OPINL
Security Exchange Name	NASDAQ

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Real estate properties:
Land	$ 840,931	$ 840,550
Buildings and improvements	2,685,988	2,652,681
Total real estate properties, gross	3,526,919	3,493,231
Accumulated depreciation	(436,346)	(387,656)
Total real estate properties, net	3,090,573	3,105,575
Assets of properties held for sale	20,716	70,877
Investments in unconsolidated joint ventures	38,533	39,756
Acquired real estate leases, net	604,233	732,382
Cash and cash equivalents	45,035	93,744
Restricted cash	12,604	6,952
Rents receivable	100,363	83,556
Deferred leasing costs, net	44,485	40,107
Other assets, net	16,503	20,187
Total assets	3,973,045	4,193,136
LIABILITIES AND SHAREHOLDERS’ EQUITY
Unsecured revolving credit facility	0	0
Senior unsecured notes, net	2,031,197	2,017,379
Mortgage notes payable, net	170,244	309,946
Liabilities of properties held for sale	331	14,693
Accounts payable and other liabilities	116,047	125,048
Due to related persons	7,349	7,141
Assumed real estate lease obligations, net	11,205	13,175
Total liabilities	2,336,373	2,487,382
Commitments and contingencies
Shareholders’ equity:
Common shares of beneficial interest, $0.01 par value: 200,000,000 shares authorized, 48,318,366 and 48,201,941 shares issued and outstanding, respectively	483	482
Additional paid in capital	2,614,346	2,612,425
Cumulative net income	185,559	177,217
Cumulative other comprehensive loss	0	(200)
Cumulative common distributions	(1,163,716)	(1,084,170)
Total shareholders’ equity	1,636,672	1,705,754
Total liabilities and shareholders’ equity	$ 3,973,045	$ 4,193,136

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Shareholders’ equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares of beneficial interest, shares authorized (in shares)	200,000,000	200,000,000
Common shares of beneficial interest, shares issued (in shares)	48,318,366	48,201,941
Common shares of beneficial interest, shares outstanding (in shares)	48,318,366	48,201,941

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Rental income	$ 145,806	$ 167,411	$ 441,294	$ 518,220
Expenses:
Real estate taxes	16,113	18,824	48,701	55,363
Utility expenses	7,564	9,518	19,777	26,369
Other operating expenses	26,366	30,376	78,033	90,204
Depreciation and amortization	62,227	74,939	189,340	226,373
Loss on impairment of real estate	2,954	8,521	2,954	14,105
Acquisition and transaction related costs	0	0	0	682
General and administrative	7,059	7,990	21,372	25,457
Total expenses	122,283	150,168	360,177	438,553
Gain on sale of real estate	0	11,463	10,822	33,538
Dividend income	0	0	0	1,960
Loss on equity securities, net	0	0	0	(44,007)
Interest and other income	2	358	738	847
Interest expense (including net amortization of debt premiums, discounts and issuance costs of $2,477, $2,560, $7,162 and $8,264, respectively)	(27,097)	(32,367)	(79,461)	(104,848)
Loss on early extinguishment of debt	0	(284)	(3,839)	(769)
Income (loss) before income tax (expense) benefit and equity in net losses of investees	(3,572)	(3,587)	9,377	(33,612)
Income tax (expense) benefit	54	(156)	(220)	(509)
Equity in net losses of investees	(279)	(196)	(815)	(573)
Net income (loss)	(3,797)	(3,939)	8,342	(34,694)
Other comprehensive income (loss):
Unrealized gain (loss) on financial instrument	85	80	200	(287)
Equity in unrealized gain (loss) of investees	0	(46)	0	91
Other comprehensive income (loss)	85	34	200	(196)
Comprehensive income (loss)	$ (3,712)	$ (3,905)	$ 8,542	$ (34,890)
Weighted average common shares outstanding (basic and diluted) (in shares)	48,132	48,073	48,111	48,051
Per common share amounts (basic and diluted):
Net income (loss) (in dollars per share)	$ (0.08)	$ (0.08)	$ 0.17	$ (0.72)

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Interest expense (including net amortization of debt premiums, discounts and issuance costs)	$ 2,477	$ 2,560	$ 7,162	$ 8,264

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Shares	Additional Paid In Capital	Cumulative Net Income	Cumulative Other Comprehensive Loss	Cumulative Common Distributions
Balance (in shares) at Dec. 31, 2018		48,082,903
Balance beginning at Dec. 31, 2018	$ 1,778,968	$ 481	$ 2,609,801	$ 146,882	$ 106	$ (978,302)
Increase (Decrease) in Shareholders' Equity
Share grants (in shares)		9,000
Share grants	865		865
Amount reclassified from cumulative other comprehensive (income) loss to net (income) loss	(371)				(371)
Net current period other comprehensive income (loss)	(32)				(32)
Net income (loss)	34,019			34,019
Distributions to common shareholders	(26,445)					(26,445)
Balance (in shares) at Mar. 31, 2019		48,091,903
Balance ending at Mar. 31, 2019	1,787,004	$ 481	2,610,666	180,901	(297)	(1,004,747)
Balance (in shares) at Dec. 31, 2018		48,082,903
Balance beginning at Dec. 31, 2018	1,778,968	$ 481	2,609,801	146,882	106	(978,302)
Increase (Decrease) in Shareholders' Equity
Net current period other comprehensive income (loss)	(196)
Balance (in shares) at Sep. 30, 2019		48,203,332
Balance ending at Sep. 30, 2019	1,666,613	$ 482	2,612,062	112,188	(461)	(1,057,658)
Balance (in shares) at Mar. 31, 2019		48,091,903
Balance beginning at Mar. 31, 2019	1,787,004	$ 481	2,610,666	180,901	(297)	(1,004,747)
Increase (Decrease) in Shareholders' Equity
Share grants (in shares)		24,000
Share grants	971		971
Share repurchases (in shares)		(2,459)
Share repurchases	(67)		(67)
Net current period other comprehensive income (loss)	(198)				(198)
Net income (loss)	(64,774)			(64,774)
Distributions to common shareholders	(26,450)					(26,450)
Balance (in shares) at Jun. 30, 2019		48,113,444
Balance ending at Jun. 30, 2019	1,696,486	$ 481	2,611,570	116,127	(495)	(1,031,197)
Increase (Decrease) in Shareholders' Equity
Share grants (in shares)		103,100
Share grants	889	$ 1	888
Share repurchases (in shares)		(13,212)
Share repurchases	(396)		(396)
Net current period other comprehensive income (loss)	34				34
Net income (loss)	(3,939)			(3,939)
Distributions to common shareholders	(26,461)					(26,461)
Balance (in shares) at Sep. 30, 2019		48,203,332
Balance ending at Sep. 30, 2019	1,666,613	$ 482	2,612,062	112,188	(461)	(1,057,658)
Balance (in shares) at Dec. 31, 2019		48,201,941
Balance beginning at Dec. 31, 2019	1,705,754	$ 482	2,612,425	177,217	(200)	(1,084,170)
Increase (Decrease) in Shareholders' Equity
Share grants	379		379
Share repurchases (in shares)		(1,012)
Share repurchases	(27)		(27)
Net current period other comprehensive income (loss)	(61)				(61)
Net income (loss)	10,840			10,840
Distributions to common shareholders	(26,511)					(26,511)
Balance (in shares) at Mar. 31, 2020		48,200,929
Balance ending at Mar. 31, 2020	1,690,374	$ 482	2,612,777	188,057	(261)	(1,110,681)
Balance (in shares) at Dec. 31, 2019		48,201,941
Balance beginning at Dec. 31, 2019	1,705,754	$ 482	2,612,425	177,217	(200)	(1,084,170)
Increase (Decrease) in Shareholders' Equity
Net current period other comprehensive income (loss)	200
Balance (in shares) at Sep. 30, 2020		48,318,366
Balance ending at Sep. 30, 2020	1,636,672	$ 483	2,614,346	185,559	0	(1,163,716)
Balance (in shares) at Mar. 31, 2020		48,200,929
Balance beginning at Mar. 31, 2020	1,690,374	$ 482	2,612,777	188,057	(261)	(1,110,681)
Increase (Decrease) in Shareholders' Equity
Share grants (in shares)		28,000
Share grants	1,121		1,121
Share repurchases (in shares)		(1,129)
Share repurchases	(30)		(30)
Net current period other comprehensive income (loss)	176				176
Net income (loss)	1,299			1,299
Distributions to common shareholders	(26,510)					(26,510)
Balance (in shares) at Jun. 30, 2020		48,227,800
Balance ending at Jun. 30, 2020	1,666,430	$ 482	2,613,868	189,356	(85)	(1,137,191)
Increase (Decrease) in Shareholders' Equity
Share grants (in shares)		108,600
Share grants	865	$ 1	864
Share repurchases (in shares)		(18,034)
Share repurchases	(386)		(386)
Amount reclassified from cumulative other comprehensive (income) loss to net (income) loss	85				85
Net current period other comprehensive income (loss)	85
Net income (loss)	(3,797)			(3,797)
Distributions to common shareholders	(26,525)					(26,525)
Balance (in shares) at Sep. 30, 2020		48,318,366
Balance ending at Sep. 30, 2020	$ 1,636,672	$ 483	$ 2,614,346	$ 185,559	$ 0	$ (1,163,716)

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income (loss)	$ 8,342	$ (34,694)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation	62,570	68,095
Net amortization of debt premiums, discounts and issuance costs	7,162	8,264
Amortization of acquired real estate leases	126,409	157,108
Amortization of deferred leasing costs	5,208	4,329
Gain on sale of real estate	(10,822)	(33,538)
Loss on impairment of real estate	2,954	14,105
Loss on early extinguishment of debt	2,701	769
Straight line rental income	(12,963)	(19,365)
Other non-cash expenses, net	1,542	1,907
Loss on equity securities, net	0	44,007
Equity in net losses of investees	815	573
Change in assets and liabilities:
Rents receivable	(4,853)	17,185
Deferred leasing costs	(10,722)	(22,759)
Other assets	(860)	(32)
Accounts payable and other liabilities	(11,593)	(30,603)
Due to related persons	208	(27,213)
Net cash provided by operating activities	166,098	148,138
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate acquisitions	(11,864)	0
Real estate improvements	(55,135)	(39,010)
Proceeds from sale of properties, net	81,528	572,131
Proceeds from repayment of mortgage note receivable	2,880	0
Proceeds from sale of RMR Inc. common shares, net	0	104,674
Net cash provided by investing activities	18,104	639,768
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of mortgage notes payable	(154,734)	(11,001)
Repayment of unsecured term loans	0	(388,000)
Repayment of senior unsecured notes	(400,000)	(350,000)
Proceeds from issuance of senior unsecured notes, net	408,932	0
Borrowings on unsecured revolving credit facility	561,467	420,000
Repayments on unsecured revolving credit facility	(561,467)	(385,000)
Payment of debt issuance costs	(1,477)	0
Repurchase of common shares	(434)	(459)
Distributions to common shareholders	(79,546)	(79,356)
Net cash used in financing activities	(227,259)	(793,816)
Decrease in cash, cash equivalents and restricted cash	(43,057)	(5,910)
Cash, cash equivalents and restricted cash at beginning of period	100,696	38,943
Cash, cash equivalents and restricted cash at end of period	57,639	33,033
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	83,116	114,226
Income taxes paid	1,097	491
SUPPLEMENTAL DISCLOSURE OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows	57,639	33,033
Unconsolidated Joint Ventures
CASH FLOWS FROM INVESTING ACTIVITIES:
Distributions in excess of earnings from unconsolidated joint ventures	408	1,973
AIC
CASH FLOWS FROM INVESTING ACTIVITIES:
Distributions in excess of earnings from unconsolidated joint ventures	$ 287	$ 0

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements of Office Properties Income Trust and its subsidiaries, or OPI, 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, 2019, or our 2019 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. 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 and assessment of impairment of real estate and the related intangibles.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or 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. We adopted ASU No. 2016-13 on January 1, 2020 using the modified retrospective approach. The implementation of this standard did not have a material impact in our condensed consolidated financial statements.

Per Common Share Amounts

Per Common Share Amounts	9 Months Ended
	Sep. 30, 2020
Earnings Per Share, Basic and Diluted [Abstract]
Per Common Share Amounts	Per Common Share AmountsWe calculate basic earnings per common share by dividing net income (loss) by the weighted average number of our common shares outstanding during the period. We calculate diluted earnings per share using the more dilutive of the two class method or the treasury stock method. Unvested share awards and other potentially dilutive common shares, together with the related impact on earnings, are considered when calculating diluted earnings per share. For the three and nine months ended September 30, 2020 and 2019, certain unvested common shares were not included in the calculation of diluted earnings per share because to do so would have been antidilutive.

Real Estate Properties

Real Estate Properties	9 Months Ended
	Sep. 30, 2020
Real Estate [Abstract]
Real Estate Properties	Real Estate Properties As of September 30, 2020, our wholly owned properties were comprised of 184 properties with approximately 24,909,000 rentable square feet, with an aggregate undepreciated carrying value of $3,544,937, including $18,018 classified as held for sale, and we had noncontrolling ownership interests in three properties totaling approximately 444,000 rentable square feet through two unconsolidated joint ventures in which we own 51% and 50% interests. We generally lease space at our properties on a gross lease, modified gross lease or net lease basis pursuant to fixed term contracts expiring between 2020 and 2040. Some of 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 September 30, 2020, we entered into 17 leases for approximately 595,000 rentable square feet for a weighted (by rentable square feet) average lease term of 10.6 years and we made commitments for approximately $6,238 of leasing related costs. During the nine months ended September 30, 2020, we entered into 60 leases for approximately 1,826,000 rentable square feet for a weighted (by rentable square feet) average lease term of 7.1 years and we made commitments for approximately $35,697 of leasing related costs. As of September 30, 2020, we have estimated unspent leasing related obligations of $61,307. 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. The future net undiscounted cash flows are subjective and are based in part on assumptions regarding hold periods, market rents and terminal capitalization rates. 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 the consideration of 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. Acquisition Activities In February 2020, we acquired a property adjacent to a property we own in Boston, MA for $11,864, including $364 of acquisition related costs. This acquisition was accounted for as an asset acquisition. The purchase price of this acquisition was allocated to land and building in the amounts of $2,618 and $9,246, respectively. In August 2020, we terminated a previously disclosed agreement to acquire an office property in Denver, CO for a purchase price of $38,100. In October 2020, we entered into an agreement to acquire three properties containing approximately 194,000 square feet adjacent to properties we own in an office park in Brookhaven, GA for $15,250, excluding acquisition related costs. Disposition Activities During the nine months ended September 30, 2020, we sold six properties with a combined 734,784 rentable square feet for an aggregate sales price of $85,363, excluding closing costs and including the repayment of one mortgage note with an outstanding principal balance of $13,095, an annual interest rate of 5.9% and a maturity date in August 2021. The sales of these properties, as presented in the table below, do not represent significant dispositions individually or in the aggregate nor do they represent a strategic shift in our business. As a result, the results of operations of these properties are included in continuing operations through the date of sale in our condensed consolidated statements of comprehensive income (loss). Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate January 2020 2 Stafford, VA 64,656 $ 14,063 $ 4,704 January 2020 1 Windsor, CT 97,256 7,000 314 February 2020 1 Lincolnshire, IL 222,717 12,000 1,176 March 2020 1 Trenton, NJ 267,025 30,100 (192) March 2020 1 Fairfax, VA 83,130 22,200 4,820 6 734,784 $ 85,363 $ 10,822 (1) Gross sales price is equal to the gross contract price, includes purchase price adjustments, if any, and excludes closing costs. As of September 30, 2020, we had four properties with an aggregate undepreciated carrying value of $18,018 under agreement to sell for a sales price of $25,100, excluding closing costs. These properties were classified as held for sale in our condensed consolidated balance sheet as of September 30, 2020. We recorded a $2,954 loss on impairment of real estate during the three months ended September 30, 2020 to adjust the carrying value of these properties to their estimated fair value less costs to sell. The operating results of these properties are included in continuing operations in our condensed consolidated statements of comprehensive income (loss). The sale of these properties was completed in October 2020. Unconsolidated Joint Ventures We own interests in two joint ventures that own three properties. We account for these investments under the equity method of accounting. As of September 30, 2020 and December 31, 2019, our investments in unconsolidated joint ventures consisted of the following: OPI Carrying Value of Investments at Joint Venture OPI Ownership September 30, December 31, 2019 Number of Properties Location Rentable Square Feet Prosperity Metro Plaza 51% $ 22,080 $ 22,483 2 Fairfax, VA 328,655 1750 H Street, NW 50% 16,453 17,273 1 Washington, D.C. 115,411 Total $ 38,533 $ 39,756 3 444,066 The following table provides a summary of the mortgage debt of our two unconsolidated joint ventures: Joint Venture Interest Rate (1) Maturity Date Principal Balance at September 30, 2020 and December 31, 2019 (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 ventures we do not own. None of the debt is recourse to us. At September 30, 2020, the aggregate unamortized basis difference of our two unconsolidated joint ventures of $7,584 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 related properties and the resulting amortization expense is included in equity in net losses of investees in our condensed consolidated statements of comprehensive income (loss).

Leases

Leases	9 Months Ended
	Sep. 30, 2020
Leases [Abstract]
Leases	Leases Revenue Recognition. Our leases provide for base rent payments and in addition may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term when we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the 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 $3,912 and $6,904 for the three months ended September 30, 2020 and 2019, respectively, and $12,963 and $19,365 for the nine months ended September 30, 2020 and 2019, respectively. Rents receivable, excluding properties classified as held for sale, include $66,499 and $54,837 of straight line rent receivables at September 30, 2020 and December 31, 2019, respectively. We do not include in our measurement of our lease receivables certain variable payments, including payments determined by changes in the index or market-based indices after the inception of the lease, certain tenant reimbursements and other income until the specific events that trigger the variable payments have occurred. Such payments totaled $18,606 and $56,654 for the three and nine months ended September 30, 2020, respectively, of which tenant reimbursements totaled $17,495 and $53,346, respectively. For the three and nine months ended September 30, 2019, such payments totaled $23,092 and $69,182, respectively, of which tenant reimbursements totaled $21,914 and $65,577, respectively. As a result of the COVID-19 pandemic, some of our tenants have requested rent assistance. As of October 27, 2020, we have granted temporary rent assistance totaling $2,550 to 19 of our tenants who represent approximately 3.6% of our annualized rental income, as defined below, as of September 30, 2020, pursuant to deferred payment plans. These tenants are obligated to pay, in most cases, the deferred rent over a 12-month period, certain of which commenced in September 2020. We have elected to use the FASB relief package regarding the application of lease accounting guidance to lease concessions provided as a result of the COVID-19 pandemic. The FASB relief package provides entities with the option to account for lease concessions resulting from the COVID-19 pandemic outside of the existing lease modification guidance if the resulting cash flows from the modified lease are substantially the same as or less than the original lease. Because the deferred rent amounts referenced above will be repaid, the cash flows from the respective leases are substantially the same as before the rent deferrals. The deferred amounts did not impact our operating results for the three and nine months ended September 30, 2020. As of September 30, 2020, deferred payments totaling $2,096 are included in rents receivable in our condensed consolidated balance sheet. Right of Use Asset and Lease Liability . For leases where we are the lessee, we are required to record a right of use asset and lease liability for all leases with an initial term greater than 12 months. As of September 30, 2020, we had one lease that met these criteria where we are the lessee, which expires on January 31, 2021. We sublease a portion of the space, which sublease expires on January 31, 2021. The values of the right of use asset and related liability representing our future obligation under the lease arrangement for which we are the lessee were $670 and $689, respectively, as of September 30, 2020, and $2,149 and $2,179, respectively, as of December 31, 2019. The right of use asset and related lease liability are included within other assets, net and accounts payable and other liabilities, respectively, within our condensed consolidated balance sheets. Rent expense incurred under the lease, net of sublease revenue, was $409 and $411 for the three months ended September 30, 2020 and 2019, respectively, and $1,301 and $1,226 for the nine months ended September 30, 2020 and 2019, respectively.
Leases	Leases Revenue Recognition. Our leases provide for base rent payments and in addition may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term when we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the 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 $3,912 and $6,904 for the three months ended September 30, 2020 and 2019, respectively, and $12,963 and $19,365 for the nine months ended September 30, 2020 and 2019, respectively. Rents receivable, excluding properties classified as held for sale, include $66,499 and $54,837 of straight line rent receivables at September 30, 2020 and December 31, 2019, respectively. We do not include in our measurement of our lease receivables certain variable payments, including payments determined by changes in the index or market-based indices after the inception of the lease, certain tenant reimbursements and other income until the specific events that trigger the variable payments have occurred. Such payments totaled $18,606 and $56,654 for the three and nine months ended September 30, 2020, respectively, of which tenant reimbursements totaled $17,495 and $53,346, respectively. For the three and nine months ended September 30, 2019, such payments totaled $23,092 and $69,182, respectively, of which tenant reimbursements totaled $21,914 and $65,577, respectively. As a result of the COVID-19 pandemic, some of our tenants have requested rent assistance. As of October 27, 2020, we have granted temporary rent assistance totaling $2,550 to 19 of our tenants who represent approximately 3.6% of our annualized rental income, as defined below, as of September 30, 2020, pursuant to deferred payment plans. These tenants are obligated to pay, in most cases, the deferred rent over a 12-month period, certain of which commenced in September 2020. We have elected to use the FASB relief package regarding the application of lease accounting guidance to lease concessions provided as a result of the COVID-19 pandemic. The FASB relief package provides entities with the option to account for lease concessions resulting from the COVID-19 pandemic outside of the existing lease modification guidance if the resulting cash flows from the modified lease are substantially the same as or less than the original lease. Because the deferred rent amounts referenced above will be repaid, the cash flows from the respective leases are substantially the same as before the rent deferrals. The deferred amounts did not impact our operating results for the three and nine months ended September 30, 2020. As of September 30, 2020, deferred payments totaling $2,096 are included in rents receivable in our condensed consolidated balance sheet. Right of Use Asset and Lease Liability . For leases where we are the lessee, we are required to record a right of use asset and lease liability for all leases with an initial term greater than 12 months. As of September 30, 2020, we had one lease that met these criteria where we are the lessee, which expires on January 31, 2021. We sublease a portion of the space, which sublease expires on January 31, 2021. The values of the right of use asset and related liability representing our future obligation under the lease arrangement for which we are the lessee were $670 and $689, respectively, as of September 30, 2020, and $2,149 and $2,179, respectively, as of December 31, 2019. The right of use asset and related lease liability are included within other assets, net and accounts payable and other liabilities, respectively, within our condensed consolidated balance sheets. Rent expense incurred under the lease, net of sublease revenue, was $409 and $411 for the three months ended September 30, 2020 and 2019, respectively, and $1,301 and $1,226 for the nine months ended September 30, 2020 and 2019, respectively.

Concentration

Concentration	9 Months Ended
	Sep. 30, 2020
Risks and Uncertainties [Abstract]
Concentration	Concentration Tenant 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. As of September 30, 2020, the U.S. Government, 11 state governments and two other government tenants combined were responsible for approximately 35.6% of our annualized rental income. As of September 30, 2019, the U.S. Government, 13 state governments and three other government tenants combined were responsible for approximately 36.3% of our annualized rental income. The U.S. Government is our largest tenant by annualized rental income and was responsible for approximately 25.2% and 25.8% of our annualized rental income as of September 30, 2020 and 2019, respectively. Geographic Concentration At September 30, 2020, our 184 wholly owned properties were located in 34 states and the District of Columbia. Properties located in Virginia, California, the District of Columbia, Texas and Maryland were responsible for 15.2%, 12.1%, 10.9%, 8.3% and 6.6% of our annualized rental income as of September 30, 2020, respectively.

Indebtedness

Indebtedness	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Indebtedness	Indebtedness Our principal debt obligations at September 30, 2020 were: (1) $2,072,000 aggregate outstanding principal amount of senior unsecured notes; and (2) $171,475 aggregate outstanding principal amount of mortgage notes. Our $750,000 revolving credit facility is governed by a credit agreement, or our credit agreement, with a syndicate of institutional lenders that includes a feature under which the maximum aggregate borrowing availability may be increased to up to $1,950,000 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, 2023 and, subject to our payment of an extension fee and meeting certain other conditions, we have the option to extend the stated maturity date of our revolving credit facility by two additional six the total amount of lending commitments under our revolving credit facility, which was 25 basis points per annum at September 30, 2020. Both the interest rate premium and facility fee are subject to adjustment based upon changes to our credit ratings. As of September 30, 2020 and December 31, 2019, the annual interest rate payable on borrowings under our revolving credit facility was 1.2% and 2.7%, respectively. The weighted average annual interest rate for borrowings under our revolving credit facility was 1.2% and 3.3% for the three months ended September 30, 2020 and 2019, respectively, and 2.0% and 3.4% for the nine months ended September 30, 2020 and 2019, respectively. As of September 30, 2020 and October 29, 2020, we had no amounts outstanding under our revolving credit facility and $750,000 available for borrowing. 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 senior unsecured notes indentures and their supplements also contain covenants, including covenants that restrict our ability to incur debts, require us to comply with certain financial covenants 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 September 30, 2020. In January 2020, we redeemed, at par plus accrued interest, all $400,000 of our 3.60% senior unsecured notes due 2020. As a result of the redemption of our 3.60% senior unsecured notes due 2020, we recognized a loss on early extinguishment of debt of $61 during the nine months ended September 30, 2020, to write off unamortized discounts. In March 2020, in connection with the sale of one property, we prepaid, at a premium plus accrued interest, a mortgage note secured by that property with an outstanding principal balance of $13,095, an annual interest rate of 5.9% and a maturity date in August 2021, which was classified in liabilities of properties held for sale in our condensed consolidated balance sheet as of December 31, 2019. As a result of the prepayment of this mortgage note, we recognized a loss on early extinguishment of debt of $508 during the nine months ended September 30, 2020, from a prepayment penalty and the write off of unamortized debt issuance costs. In March 2020, we prepaid, at a premium plus accrued interest, a mortgage note secured by one property with an outstanding principal balance of $66,780, an annual interest rate of 4.0% and a maturity date in September 2030. As a result of the prepayment of this mortgage note, we recognized a loss on early extinguishment of debt of $2,713 during the nine months ended September 30, 2020, from a prepayment penalty and the write off of unamortized discounts. In April 2020, we prepaid, at par plus accrued interest, a mortgage note secured by one property with an outstanding principal balance of $32,677, an annual interest rate of 5.7% and a maturity date in July 2020. As a result of the prepayment of this mortgage note, we recognized a gain on early extinguishment of debt of $163 during the nine months ended September 30, 2020, from the write off of unamortized premiums. In June 2020, we issued $150,000 of our 6.375% senior unsecured notes due 2050 in an underwritten public offering. In connection with this offering, we granted the underwriters a 30 day option to purchase up to an additional $22,500 aggregate principal amount of these notes. In July 2020, the underwriters partially exercised this option to purchase an additional $12,000 of these notes. The aggregate net proceeds from this offering were $156,186, after underwriters’ discounts and offering expenses. These notes require quarterly payments of interest only through maturity and may be repaid at par (plus accrued and unpaid interest) on or after June 23, 2025. In August 2020, we repaid at maturity, at par plus accrued interest, a mortgage note secured by one property with an outstanding principal balance of $39,635 and an annual interest rate of 2.2%. In September 2020, we issued $250,000 of our 4.50% senior unsecured notes due 2025 in an underwritten public offering. These notes are a further issuance of our existing $400,000 of senior unsecured notes due 2025 that were initially issued by Select Income REIT, or SIR, in February 2015, which we assumed in connection with our acquisition of SIR in a merger transaction on December 31, 2018. The public offering price of these notes was 101.414% of the principal amount, raising net proceeds of $251,269, after underwriters’ discounts and estimated offering expenses. These notes require semi-annual payments of interest only through maturity.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value of Assets and Liabilities	Fair Value of Assets and Liabilities The following table presents certain of our assets measured at fair value at September 30, 2020, 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 Description Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Non-recurring Fair Value Measurements Assets Assets of properties held for sale (1) $ 21,446 $ — $ 21,446 $ — (1) We recorded impairment charges of $2,954 to reduce the carrying value of four properties that are classified as held for sale in our condensed consolidated balance sheet to their estimated fair value, less costs to sell of $786, based upon a negotiated sale price with a third party buyer (a Level 2 input as defined in the fair value hierarchy under GAAP). See Note 4 for more information. In addition to the assets described in the table above, our financial instruments include our cash and cash equivalents, restricted cash, rents receivable, accounts payable, a revolving credit facility, senior unsecured notes, mortgage notes payable, amounts due to related persons, other accrued expenses and security deposits. At September 30, 2020 and December 31, 2019, the fair values of our financial instruments approximated their carrying values in our condensed consolidated financial statements, due to their short term nature or floating interest rates, except as follows: As of September 30, 2020 As of December 31, 2019 Financial Instrument Carrying Value (1) Fair Value Carrying Value (1) Fair Value Senior unsecured notes, 3.60% interest rate, due in 2020 (2) $ — $ — $ 399,934 $ 400,048 Senior unsecured notes, 4.00% interest rate, due in 2022 298,348 304,746 297,657 306,096 Senior unsecured notes, 4.15% interest rate, due in 2022 298,589 303,359 297,795 307,221 Senior unsecured notes, 4.25% interest rate, due in 2024 341,729 352,331 340,018 364,602 Senior unsecured notes, 4.50% interest rate, due in 2025 (3) 635,114 659,029 381,055 419,578 Senior unsecured notes, 5.785% interest rate, due in 2046 301,178 310,124 300,920 322,028 Senior unsecured notes, 6.375% interest rate, due in 2050 (4) 156,239 165,758 — — Mortgage notes payable (5) 170,244 174,567 323,074 331,675 Total $ 2,201,441 $ 2,269,914 $ 2,340,453 $ 2,451,248 (1) Includes unamortized debt premiums, discounts and issuance costs totaling $42,034 and $45,756 as of September 30, 2020 and December 31, 2019, respectively. (2) These senior unsecured notes were redeemed in January 2020. (3) An additional $250,000 of these senior unsecured notes were issued in September 2020. (4) $150,000 of these senior unsecured notes were issued in June 2020. In July 2020, we issued an additional $12,000 of these senior unsecured notes in connection with the underwriters partial exercise of their option to purchase additional notes. (5) Balance as of December 31, 2019 includes one mortgage note with a carrying value of $13,128 net of unamortized issuance costs totaling $38 which is classified in liabilities of properties held for sale in our condensed consolidated balance sheet. This mortgage note was secured by a property in Fairfax, VA that was sold in March 2020. The mortgage note was repaid at closing. We estimated the fair value of our senior unsecured notes (except for our senior unsecured notes due 2046 and 2050) using an average of the bid and ask price of the notes (Level 2 inputs as defined in the fair value hierarchy under GAAP) as of the measurement date. We estimated the fair value of our senior unsecured notes due 2046 and 2050 based on the closing price on The Nasdaq Stock Market LLC, or Nasdaq, (Level 1 inputs as defined in the fair value hierarchy under GAAP) as of the measurement date. We estimated the fair values of our mortgage notes payable using discounted cash flow analyses and currently prevailing market rates (Level 3 inputs as defined in the fair value hierarchy under GAAP) as of the measurement date. Because Level 3 inputs are unobservable, our estimated fair value may differ materially from the actual fair value.

Shareholders' Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity Share Awards On May 27, 2020, in accordance with our Trustee compensation arrangements, we awarded to each of our eight Trustees 3,500 of our common shares, valued at $26.61 per share, the closing price of our common shares on Nasdaq on that day. On September 17, 2020, we awarded under our equity compensation plan an aggregate of 108,600 of our common shares, valued at $23.04 per share, the closing price of our common shares on Nasdaq on that day, to our officers and certain other employees of RMR LLC. Share Purchases During the three and nine months ended September 30, 2020, we purchased an aggregate of 17,448 and 19,589 of our common shares, respectively, valued at weighted average share prices of $21.61 and $22.15 per share, respectively, from one of our Trustees, our officers and certain other current and former officers and employees of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. Distributions During the nine months ended September 30, 2020, we declared and paid regular quarterly distributions to common shareholders as follows: Declaration Date Record Date Paid Date Distributions Per Common Share Total Distributions January 16, 2020 January 27, 2020 February 20, 2020 $ 0.55 $ 26,511 April 2, 2020 April 13, 2020 May 21, 2020 0.55 26,510 July 16, 2020 July 27, 2020 August 20, 2020 0.55 26,525 $ 1.65 $ 79,546 On October 15, 2020, we declared a regular quarterly distribution to common shareholders of record on October 26, 2020 of $0.55 per share, or approximately $26,600. We expect to pay this distribution on or about November 19, 2020.

Business and Property Managemen

Business and Property Management Agreements with RMR LLC	9 Months Ended
	Sep. 30, 2020
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 $4,236 and $5,159 for the three months ended September 30, 2020 and 2019, respectively, and $13,237 and $16,203 for the nine months ended September 30, 2020 and 2019, respectively. Based on our common share total return, as defined in our business management agreement, as of September 30, 2020 and 2019, no estimated incentive fees are included in the net business management fees we recognized for the three or nine months ended September 30, 2020 or 2019. The actual amount of annual incentive fees for 2020, if any, will be based on our common share total return, as defined in our business management agreement, for the three year period ending December 31, 2020, and will be payable in 2021. We did not incur an incentive fee payable to RMR LLC for the year ended December 31, 2019. We include business management fees in general and administrative expenses in our condensed consolidated statements of comprehensive income (loss). Pursuant to our property management agreement with RMR LLC, we recognized aggregate net property management and construction supervision fees of $5,189 and $5,622 for the three months ended September 30, 2020 and 2019, respectively, and $15,381 and $16,605 for the nine months ended September 30, 2020 and 2019, 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 or arranged by RMR LLC on our behalf. We are generally not responsible for payment of RMR LLC’s employment, office or administrative

Related Person Transactions

Related Person Transactions	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions We have relationships and historical and continuing transactions with RMR LLC, The RMR Group Inc., or RMR Inc., and others related to them, including other companies to which RMR LLC or its subsidiaries provide management services and some of which have trustees, directors or officers who are also our Trustees or officers. RMR LLC is a majority owned subsidiary of RMR Inc. The Chair of our Board of Trustees and one of our Managing Trustees, Adam Portnoy, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., a managing director, the president and chief executive officer of RMR Inc. and an officer and employee of RMR LLC. David Blackman, our other Managing Trustee and our President and Chief Executive Officer, also serves as an officer of RMR LLC. Mr. Blackman has announced his decision to retire and, therefore, resign as our President and Chief Executive Officer, effective December 31, 2020, and as our Managing Trustee, effective as of June 30, 2021 or such earlier date as his successor Managing Trustee is elected to our Board. In replacement of Mr. Blackman, Christopher J. Bilotto has been appointed as our President and Chief Operating Officer, effective January 1, 2021. Mr. Bilotto currently serves as our Vice President and Chief Operating Officer, and he is an officer and employee of RMR LLC. In addition, each of our other officers is also an officer and employee of RMR LLC. Some of our Independent Trustees also serve as independent trustees or independent directors of other public companies to which RMR LLC or its subsidiaries provide management services. Adam Portnoy serves as chair of the boards of trustees or boards of directors of several of these public companies and as a managing director or managing trustee of these public companies. Other officers of RMR LLC, including Mr. Blackman and certain of our other officers, serve as managing trustees, managing directors or officers of certain of these companies. See Note 9 for further information relating to our awards of common shares to our officers and certain other employees of RMR LLC in September 2020 and our repurchases of common shares from one of our Trustees, our officers, and certain other current and former employees of RMR LLC in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares to them. We include amounts recognized as expense for awards of our common shares to our officers and to other RMR LLC employees in general and administrative expenses in our condensed consolidated statements of comprehensive income (loss). Our Manager, RMR LLC. We have two agreements with RMR LLC to provide management services to us. For more information regarding our management agreements with RMR LLC, see Note 10. Leases with RMR LLC. We lease office space to RMR LLC in certain of our properties for RMR LLC’s property management offices. Pursuant to our lease agreements with RMR LLC, we recognized rental income from RMR LLC for leased office space of $282 and $288 for the three months ended September 30, 2020 and 2019, respectively, and $836 and $854 for the nine months ended September 30, 2020 and 2019, respectively. Affiliates Insurance Company, or AIC . Until its dissolution on February 13, 2020 we, ABP Trust and five other companies to which RMR LLC provides management services owned AIC in equal amounts. We and the other AIC shareholders historically participated in a combined property insurance program arranged and insured or reinsured in part by AIC. The policies under that program expired on June 30, 2019, and we and the other AIC shareholders elected not to renew the AIC property insurance program; we have instead purchased standalone property insurance coverage with unrelated third party insurance providers. As of September 30, 2020 and December 31, 2019, our investment in AIC had a carrying value of $11 and $298, respectively. These amounts are included in other assets, net in our condensed consolidated balance sheets. In June 2020, we received an additional liquidating distribution of approximately $287 from AIC in connection with its dissolution. We did not recognize any income related to our investment in AIC for the three or nine months ended September 30, 2020, respectively, and we recognized income of $83 and $617 for the three and nine months ended September 30, 2019, respectively. These amounts are included in equity in net losses of investees in our condensed consolidated statements of comprehensive income (loss). Our other comprehensive loss for the 2019 period includes our proportionate part of unrealized gains (losses) on fixed income securities, which were owned by AIC, related to our investment in AIC. For more information about these and other such relationships and certain other related person transactions, refer to our 2019 Annual Report.

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Recent Accounting Pronouncements	In June 2016, the Financial Accounting Standards Board, or FASB, issued Accounting Standards Update, or ASU, No. 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments
Revenue Recognition	Revenue Recognition. Our leases provide for base rent payments and in addition may include variable payments. Rental income from operating leases, including any payments derived by index or market-based indices, is recognized on a straight line basis over the lease term when we have determined that the collectability of substantially all of the lease payments is probable. Some of our leases have options to extend or terminate the lease exercisable at the option of our tenants, which are considered when determining the lease term. In certain circumstances, some leases provide the tenant with the right to terminate if the legislature or other funding authority does not appropriate the funding necessary for the 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.

Real Estate Properties (Tables)

Real Estate Properties (Tables)	9 Months Ended
	Sep. 30, 2020
Real Estate [Abstract]
Schedule of disposed assets	The sales of these properties, as presented in the table below, do not represent significant dispositions individually or in the aggregate nor do they represent a strategic shift in our business. As a result, the results of operations of these properties are included in continuing operations through the date of sale in our condensed consolidated statements of comprehensive income (loss). Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate January 2020 2 Stafford, VA 64,656 $ 14,063 $ 4,704 January 2020 1 Windsor, CT 97,256 7,000 314 February 2020 1 Lincolnshire, IL 222,717 12,000 1,176 March 2020 1 Trenton, NJ 267,025 30,100 (192) March 2020 1 Fairfax, VA 83,130 22,200 4,820 6 734,784 $ 85,363 $ 10,822 (1) Gross sales price is equal to the gross contract price, includes purchase price adjustments, if any, and excludes closing costs.
Schedule of joint ventures	As of September 30, 2020 and December 31, 2019, our investments in unconsolidated joint ventures consisted of the following: OPI Carrying Value of Investments at Joint Venture OPI Ownership September 30, December 31, 2019 Number of Properties Location Rentable Square Feet Prosperity Metro Plaza 51% $ 22,080 $ 22,483 2 Fairfax, VA 328,655 1750 H Street, NW 50% 16,453 17,273 1 Washington, D.C. 115,411 Total $ 38,533 $ 39,756 3 444,066 The following table provides a summary of the mortgage debt of our two unconsolidated joint ventures: Joint Venture Interest Rate (1) Maturity Date Principal Balance at September 30, 2020 and December 31, 2019 (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 ventures we do not own. None of the debt is recourse to us.

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair value measurements, recurring and nonrecurring	The following table presents certain of our assets measured at fair value at September 30, 2020, 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 Description Total Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Non-recurring Fair Value Measurements Assets Assets of properties held for sale (1) $ 21,446 $ — $ 21,446 $ — (1) We recorded impairment charges of $2,954 to reduce the carrying value of four properties that are classified as held for sale in our condensed consolidated balance sheet to their estimated fair value, less costs to sell of $786, based upon a negotiated sale price with a third party buyer (a Level 2 input as defined in the fair value hierarchy under GAAP). See Note 4 for more information.
Schedule of fair value and carrying value of financial instruments	At September 30, 2020 and December 31, 2019, the fair values of our financial instruments approximated their carrying values in our condensed consolidated financial statements, due to their short term nature or floating interest rates, except as follows: As of September 30, 2020 As of December 31, 2019 Financial Instrument Carrying Value (1) Fair Value Carrying Value (1) Fair Value Senior unsecured notes, 3.60% interest rate, due in 2020 (2) $ — $ — $ 399,934 $ 400,048 Senior unsecured notes, 4.00% interest rate, due in 2022 298,348 304,746 297,657 306,096 Senior unsecured notes, 4.15% interest rate, due in 2022 298,589 303,359 297,795 307,221 Senior unsecured notes, 4.25% interest rate, due in 2024 341,729 352,331 340,018 364,602 Senior unsecured notes, 4.50% interest rate, due in 2025 (3) 635,114 659,029 381,055 419,578 Senior unsecured notes, 5.785% interest rate, due in 2046 301,178 310,124 300,920 322,028 Senior unsecured notes, 6.375% interest rate, due in 2050 (4) 156,239 165,758 — — Mortgage notes payable (5) 170,244 174,567 323,074 331,675 Total $ 2,201,441 $ 2,269,914 $ 2,340,453 $ 2,451,248 (1) Includes unamortized debt premiums, discounts and issuance costs totaling $42,034 and $45,756 as of September 30, 2020 and December 31, 2019, respectively. (2) These senior unsecured notes were redeemed in January 2020. (3) An additional $250,000 of these senior unsecured notes were issued in September 2020. (4) $150,000 of these senior unsecured notes were issued in June 2020. In July 2020, we issued an additional $12,000 of these senior unsecured notes in connection with the underwriters partial exercise of their option to purchase additional notes. (5) Balance as of December 31, 2019 includes one mortgage note with a carrying value of $13,128 net of unamortized issuance costs totaling $38 which is classified in liabilities of properties held for sale in our condensed consolidated balance sheet. This mortgage note was secured by a property in Fairfax, VA that was sold in March 2020. The mortgage note was repaid at closing.

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Distributions Made to Limited Partner, by Distribution	During the nine months ended September 30, 2020, we declared and paid regular quarterly distributions to common shareholders as follows: Declaration Date Record Date Paid Date Distributions Per Common Share Total Distributions January 16, 2020 January 27, 2020 February 20, 2020 $ 0.55 $ 26,511 April 2, 2020 April 13, 2020 May 21, 2020 0.55 26,510 July 16, 2020 July 27, 2020 August 20, 2020 0.55 26,525 $ 1.65 $ 79,546

Real Estate Properties - Additi

Real Estate Properties - Additional Information (Details) $ in Thousands	1 Months Ended		3 Months Ended			9 Months Ended
	Aug. 31, 2020USD ($)	Feb. 29, 2020USD ($)	Dec. 31, 2020USD ($)ft²property	Sep. 30, 2020USD ($)ft²propertylease	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)ft²joint_ventureleaseproperty	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Real Estate Properties [Line Items]
Real estate aggregate undepreciated carrying value				$ 3,526,919		$ 3,526,919		$ 3,493,231
Number of joint ventures | joint_venture						2
Number of leases entered | lease				17		60
Rentable square feet (in sqft) | ft²				595,000		1,826,000
Weighted average lease term				10 years 7 months 6 days		7 years 1 month 6 days
Expenditures committed on leases				$ 6,238		$ 35,697
Committed but unspent tenant related obligations estimated				61,307		61,307
Payments to acquire real estate						11,864	$ 0
Loss on impairment of real estate				$ 2,954	$ 8,521	$ 2,954	$ 14,105
Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Number of properties | property				4		4
Real estate held-for-sale				$ 18,018		$ 18,018
Gross sales price						25,100
Loss on impairment of real estate				$ 2,954		$ 2,954
Boston, MA
Real Estate Properties [Line Items]
Payments to acquire real estate		$ 11,864
Acquisition related costs		364
Denver, CO
Real Estate Properties [Line Items]
Real estate acquisition, terminated agreement	$ 38,100
Brookhaven, GA | Subsequent Event | Forecast
Real Estate Properties [Line Items]
Rentable area of properties (in square feet) | ft²			194,000
Payments to acquire real estate			$ 15,250
Number of properties acquired | property			3
Land | Boston, MA
Real Estate Properties [Line Items]
Purchase price of asset acquisition		2,618
Building | Boston, MA
Real Estate Properties [Line Items]
Purchase price of asset acquisition		$ 9,246
Unconsolidated Joint Ventures
Real Estate Properties [Line Items]
Number of properties | property				3		3
Rentable area of properties (in square feet) | ft²				444,066		444,066
Number of buildings, noncontrolling interest | property						3
Joint Venture 2
Real Estate Properties [Line Items]
Ownership percentage				51.00%		51.00%
Joint Venture 1
Real Estate Properties [Line Items]
Ownership percentage				50.00%		50.00%
Continuing operations
Real Estate Properties [Line Items]
Number of properties | property				184		184
Rentable area of properties (in square feet) | ft²				24,909,000		24,909,000
Real estate aggregate undepreciated carrying value				$ 3,544,937		$ 3,544,937

Real Estate Properties - Dispos

Real Estate Properties - Disposition Activities (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)ft²property	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)ft²property	Sep. 30, 2019USD ($)	Mar. 31, 2020
Real Estate Properties [Line Items]
Gain (Loss) on Sale of Real Estate	$ 0	$ 11,463	$ 10,822	$ 33,538
Disposed of by Sale
Real Estate Properties [Line Items]
Number of Properties | property	6		6
Rentable area of properties (in square feet) | ft²	734,784		734,784
Gross Sale Price			$ 85,363
Gain (Loss) on Sale of Real Estate			$ 10,822
Disposed of by Sale | Stafford, VA
Real Estate Properties [Line Items]
Number of Properties | property	2		2
Rentable area of properties (in square feet) | ft²	64,656		64,656
Gross Sale Price			$ 14,063
Gain (Loss) on Sale of Real Estate			$ 4,704
Disposed of by Sale | Windsor, CT
Real Estate Properties [Line Items]
Number of Properties | property	1		1
Rentable area of properties (in square feet) | ft²	97,256		97,256
Gross Sale Price			$ 7,000
Gain (Loss) on Sale of Real Estate			$ 314
Disposed of by Sale | Lincolnshire, IL
Real Estate Properties [Line Items]
Number of Properties | property	1		1
Rentable area of properties (in square feet) | ft²	222,717		222,717
Gross Sale Price			$ 12,000
Gain (Loss) on Sale of Real Estate			$ 1,176
Disposed of by Sale | Trenton, NJ
Real Estate Properties [Line Items]
Number of Properties | property	1		1
Rentable area of properties (in square feet) | ft²	267,025		267,025
Gross Sale Price			$ 30,100
Gain (Loss) on Sale of Real Estate			$ (192)
Disposed of by Sale | Fairfax, VA
Real Estate Properties [Line Items]
Number of Properties | property	1		1
Rentable area of properties (in square feet) | ft²	83,130		83,130
Gross Sale Price			$ 22,200
Gain (Loss) on Sale of Real Estate			$ 4,820
Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Number of Properties | property	4		4
Gross Sale Price			$ 25,100
Mortgage notes payable, 5.9% interest rate, due in 2021 | Mortgages
Real Estate Properties [Line Items]
Principal balance			$ 13,095
Interest rate (as a percent)	5.90%		5.90%		5.90%

Real Estate Properties - Schedu

Real Estate Properties - Schedule of Joint Ventures (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)ft²joint_ventureproperty	Dec. 31, 2019USD ($)
Real Estate [Line Items]
Number of joint ventures | joint_venture	2
Unconsolidated Joint Ventures
Real Estate [Line Items]
Number of Properties | property	3
Investment at carrying value	$ 38,533	$ 39,756
Rentable Square Feet (in square feet) | ft²	444,066
Unamortized basis difference	$ 7,584
Unconsolidated Joint Ventures | Prosperity Metro Plaza
Real Estate [Line Items]
Number of Properties | property	2
Ownership percentage	51.00%
Investment at carrying value	$ 22,080	22,483
Rentable Square Feet (in square feet) | ft²	328,655
Unconsolidated Joint Ventures | 1750 H Street, NW
Real Estate [Line Items]
Number of Properties | property	1
Ownership percentage	50.00%
Investment at carrying value	$ 16,453	$ 17,273
Rentable Square Feet (in square feet) | ft²	115,411
Mortgages | Unconsolidated Joint Ventures
Real Estate [Line Items]
Interest rate (as a percent)	3.93%
Principal balance	$ 82,000
Mortgages | Unconsolidated Joint Ventures | Prosperity Metro Plaza
Real Estate [Line Items]
Interest rate (as a percent)	4.09%
Principal balance	$ 50,000
Mortgages | Unconsolidated Joint Ventures | 1750 H Street, NW
Real Estate [Line Items]
Interest rate (as a percent)	3.69%
Principal balance	$ 32,000

Leases - Lease Receivables (Det

Leases - Lease Receivables (Details) $ in Thousands	Jul. 27, 2020USD ($)tenant	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Subsequent Event [Line Items]
Straight line rent adjustments		$ 3,912	$ 6,904	$ 12,963	$ 19,365
Straight line rent receivables		66,499		66,499		$ 54,837
Variable lease, income		18,606	23,092	56,654	69,182
Tenant reimbursements and other income		$ 17,495	$ 21,914	53,346	65,577
Deferred payments				4,853	$ (17,185)
COVID-19 Pandemic
Subsequent Event [Line Items]
Temporary rental assistance	$ 2,550
Number of tenants granted rent assistance | tenant	19
Percentage of annualized rental income	3.60%
Deferred payment plan period	12 months
Deferred payments				$ 2,096

Leases - Right of Use Asset and

Leases - Right of Use Asset and Lease Liability (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)lease	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)lease	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Leases [Abstract]
Number of leases | lease	1		1
Operating lease, right-of-use asset	$ 670		$ 670		$ 2,149
Operating lease liability	689		689		$ 2,179
Operating lease, rent expense	$ 409	$ 411	$ 1,301	$ 1,226

Concentration (Details)

Concentration (Details)	9 Months Ended
	Sep. 30, 2020government_tenantstate_governmentstateproperty	Sep. 30, 2019state_governmentgovernment_tenant
Concentration
Number of state governments		13
Number of other governments | government_tenant	2	3
Annualized rental income, excluding properties classified as discontinued operations | Virginia
Concentration
Concentration risk percentage	15.20%
Annualized rental income, excluding properties classified as discontinued operations | California
Concentration
Concentration risk percentage	12.10%
Annualized rental income, excluding properties classified as discontinued operations | District of Columbia
Concentration
Concentration risk percentage	10.90%
Annualized rental income, excluding properties classified as discontinued operations | Texas
Concentration
Concentration risk percentage	8.30%
Annualized rental income, excluding properties classified as discontinued operations | Maryland
Concentration
Concentration risk percentage	6.60%
Annualized rental income, excluding properties classified as discontinued operations | Tenant concentration | U.S. Government, state governments and Other Four Government
Concentration
Number of state governments	11
Concentration risk percentage	35.60%	36.30%
Annualized rental income, excluding properties classified as discontinued operations | Tenant concentration | U.S. Government
Concentration
Concentration risk percentage	25.20%	25.80%
Continuing operations
Concentration
Number of wholly owned properties | property	184
Number of states in which acquired properties located | state	34

Indebtedness - Debt Obligations

Indebtedness - Debt Obligations (Details) $ in Thousands	1 Months Ended						3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)buildingextension_option	Aug. 31, 2020USD ($)property	Jun. 30, 2020USD ($)	Apr. 30, 2020USD ($)	Mar. 31, 2020USD ($)property	Jan. 31, 2020USD ($)	Sep. 30, 2020USD ($)buildingextension_option	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)buildingextension_option	Sep. 30, 2019USD ($)	Oct. 29, 2020USD ($)	Jul. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Borrowings outstanding	$ 0						$ 0		$ 0				$ 0
Aggregate principal amount on secured properties	$ 171,475						171,475		171,475
Loss on early extinguishment of debt							$ 0	$ (284)	$ (3,839)	$ (769)
Number of properties sold | property					1
Number of collateral properties | property		1
Number of buildings secured by mortgage notes | building	7						7		7
Aggregate net book value of secured properties	$ 307,837						$ 307,837		$ 307,837
Senior unsecured notes, 3.60% interest rate, due in 2020
Debt Instrument [Line Items]
Interest rate (as a percent)	3.60%						3.60%		3.60%
Senior unsecured notes, 6.375% interest rate, due in 2050
Debt Instrument [Line Items]
Interest rate (as a percent)	6.375%						6.375%		6.375%
Unsecured revolving credit facility
Debt Instrument [Line Items]
Borrowings outstanding	$ 0						$ 0		$ 0
Maximum borrowing capacity on revolving credit facility	750,000						750,000		750,000
Aggregate principal amount on secured properties	$ 1,950,000						$ 1,950,000		$ 1,950,000
Number of extension options | extension_option	2						2		2
Extension option duration									6 months
Facility fee (as a percent)									0.25%
Interest rate (as a percent)	1.20%						1.20%		1.20%				2.70%
The weighted average annual interest rate (as a percent)							1.20%	3.30%	2.00%	3.40%
Line of credit facility, remaining borrowing capacity	$ 750,000						$ 750,000		$ 750,000
Unsecured revolving credit facility | Subsequent Event
Debt Instrument [Line Items]
Borrowings outstanding											$ 0
Line of credit facility, remaining borrowing capacity											$ 750,000
Senior unsecured notes
Debt Instrument [Line Items]
Borrowings outstanding	$ 2,072,000						$ 2,072,000		$ 2,072,000
LIBOR | Unsecured revolving credit facility
Debt Instrument [Line Items]
Interest rate premium (as a percent)									1.10%
Senior unsecured notes | Senior unsecured notes, 3.60% interest rate, due in 2020
Debt Instrument [Line Items]
Interest rate (as a percent)						3.60%
Repayments of debt						$ 400,000
Loss on early extinguishment of debt									$ 61
Senior unsecured notes | Senior unsecured notes, 6.375% interest rate, due in 2050
Debt Instrument [Line Items]
Interest rate (as a percent)			6.375%
Principal balance			$ 150,000
Debt instrument, option to purchase period			30 days
Principal balance of additional option			$ 22,500									$ 12,000
Proceeds from issuance of long-term debt			156,186
Senior unsecured notes | Senior unsecured notes, 4.50% interest rate, due in 2025
Debt Instrument [Line Items]
Interest rate (as a percent)	4.50%						4.50%		4.50%
Principal balance	$ 250,000						$ 250,000		$ 250,000
Senior unsecured notes | Senior Unsecured Notes Due In 2025 [Member]
Debt Instrument [Line Items]
Principal balance	$ 400,000						400,000		400,000
Proceeds from issuance of long-term debt			$ 251,269
Debt instrument, offering price, percentage of principal amount	101.414%
Mortgages
Debt Instrument [Line Items]
Outstanding principal amount	$ 171,475						$ 171,475		$ 171,475
Mortgages | Mortgage notes payable, 5.9% interest rate, due in 2021
Debt Instrument [Line Items]
Interest rate (as a percent)	5.90%				5.90%		5.90%		5.90%
Repayments of debt					$ 13,095
Loss on early extinguishment of debt									$ 508
Mortgages | Mortgage notes payable, 4.0% interest rate, due in 2030
Debt Instrument [Line Items]
Interest rate (as a percent)					4.00%
Repayments of debt					$ 66,780
Loss on early extinguishment of debt									2,713
Mortgages | Mortgage notes payable, 5.7% interest rate, due in 2020
Debt Instrument [Line Items]
Interest rate (as a percent)				5.70%
Repayments of debt				$ 32,677
Loss on early extinguishment of debt									$ 163
Mortgages | Mortgage notes payable, 2.2% interest rate, due in 2020
Debt Instrument [Line Items]
Interest rate (as a percent)		2.20%
Repayments of debt		$ 39,635

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Non-recurring Fair Value Measurements Assets (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)property	Sep. 30, 2019USD ($)
Fair Value of Assets and Liabilities
Loss on impairment of real estate assets	$ 2,954	$ 8,521	$ 2,954	$ 14,105
Disposal Group, Held-for-sale, Not Discontinued Operations
Fair Value of Assets and Liabilities
Loss on impairment of real estate assets	2,954		$ 2,954
Number of impaired properties | property			4
Sale of real estate properties transactions costs			$ 786
Nonrecurring
Fair Value of Assets and Liabilities
Assets of properties held for sales	21,446		21,446
Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value of Assets and Liabilities
Assets of properties held for sales	0		0
Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value of Assets and Liabilities
Assets of properties held for sales	21,446		21,446
Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value of Assets and Liabilities
Assets of properties held for sales	$ 0		$ 0

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jul. 31, 2020	Jun. 30, 2020	Jan. 31, 2020	Dec. 31, 2019
Fair Value of Financial Instruments
Senior notes	$ 2,031,197				$ 2,017,379
Mortgage notes payable, net	$ 170,244				309,946
Senior unsecured notes, 3.60% interest rate, due in 2020
Fair Value of Financial Instruments
Interest rate (as a percent)	3.60%
Senior unsecured notes, 4.00% interest rate, due in 2022
Fair Value of Financial Instruments
Interest rate (as a percent)	4.00%
Senior unsecured notes, 4.15% interest rate, due in 2022
Fair Value of Financial Instruments
Interest rate (as a percent)	4.15%
Senior unsecured notes, 4.25% interest rate, due in 2024
Fair Value of Financial Instruments
Interest rate (as a percent)	4.25%
Senior unsecured notes, 4.50% interest rate, due in 2025
Fair Value of Financial Instruments
Interest rate (as a percent)	4.50%
Senior unsecured notes, 5.785% interest rate, due in 2046
Fair Value of Financial Instruments
Interest rate (as a percent)	5.785%
Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Interest rate (as a percent)	6.375%
Senior Notes And Mortgages
Fair Value of Financial Instruments
Unamortized debt premiums, discounts and issuance costs	$ 42,034				45,756
Mortgages
Fair Value of Financial Instruments
Outstanding principal amount	$ 171,475
Senior unsecured notes | Senior unsecured notes, 3.60% interest rate, due in 2020
Fair Value of Financial Instruments
Interest rate (as a percent)				3.60%
Senior unsecured notes | Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Interest rate (as a percent)			6.375%
Principal balance			$ 150,000
Principal balance of additional option		$ 12,000	$ 22,500
Senior unsecured notes | Senior unsecured notes, 4.50% interest rate, due in 2025
Fair Value of Financial Instruments
Interest rate (as a percent)	4.50%
Principal balance	$ 250,000
Disposal Group, Held-for-sale, Not Discontinued Operations | Mortgages
Fair Value of Financial Instruments
Outstanding principal amount					13,128
Unamortized issuance costs					38
Carrying Amount
Fair Value of Financial Instruments
Mortgage notes payable, net	170,244				323,074
Fair value of financial instruments	2,201,441				2,340,453
Carrying Amount | Senior unsecured notes, 3.60% interest rate, due in 2020
Fair Value of Financial Instruments
Senior notes	0				399,934
Carrying Amount | Senior unsecured notes, 4.00% interest rate, due in 2022
Fair Value of Financial Instruments
Senior notes	298,348				297,657
Carrying Amount | Senior unsecured notes, 4.15% interest rate, due in 2022
Fair Value of Financial Instruments
Senior notes	298,589				297,795
Carrying Amount | Senior unsecured notes, 4.25% interest rate, due in 2024
Fair Value of Financial Instruments
Senior notes	341,729				340,018
Carrying Amount | Senior unsecured notes, 4.50% interest rate, due in 2025
Fair Value of Financial Instruments
Senior notes	635,114				381,055
Carrying Amount | Senior unsecured notes, 5.785% interest rate, due in 2046
Fair Value of Financial Instruments
Senior notes	301,178				300,920
Carrying Amount | Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Senior notes	156,239				0
Fair Value
Fair Value of Financial Instruments
Mortgage notes payable, net	174,567				331,675
Fair value of financial instruments	2,269,914				2,451,248
Fair Value | Senior unsecured notes, 3.60% interest rate, due in 2020
Fair Value of Financial Instruments
Senior notes	0				400,048
Fair Value | Senior unsecured notes, 4.00% interest rate, due in 2022
Fair Value of Financial Instruments
Senior notes	304,746				306,096
Fair Value | Senior unsecured notes, 4.15% interest rate, due in 2022
Fair Value of Financial Instruments
Senior notes	303,359				307,221
Fair Value | Senior unsecured notes, 4.25% interest rate, due in 2024
Fair Value of Financial Instruments
Senior notes	352,331				364,602
Fair Value | Senior unsecured notes, 4.50% interest rate, due in 2025
Fair Value of Financial Instruments
Senior notes	659,029				419,578
Fair Value | Senior unsecured notes, 5.785% interest rate, due in 2046
Fair Value of Financial Instruments
Senior notes	310,124				322,028
Fair Value | Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Senior notes	$ 165,758				$ 0

Shareholders' Equity (Details)

Shareholders' Equity (Details) $ / shares in Units, $ in Thousands

Oct. 15, 2020USD ($)$ / shares

Sep. 17, 2020$ / sharesshares

Aug. 20, 2020USD ($)$ / shares

May 27, 2020trustee$ / sharesshares

May 21, 2020USD ($)$ / shares

Feb. 20, 2020USD ($)$ / shares

Sep. 30, 2020$ / sharesshares

Jun. 30, 2020shares

Mar. 31, 2020shares

Sep. 30, 2019shares

Jun. 30, 2019shares

Sep. 30, 2020USD ($)$ / sharesshares

Sep. 30, 2019USD ($)

Share Awards

Number of trustees | trustee

8

Cash distribution to common shareholders (in dollars per share)

$ 0.55

$ 0.55

$ 0.55

$ 1.65

Distributions to common shareholders | $

$ 26,525

$ 26,510

$ 26,511

$ 79,546

$ 79,356

Subsequent Event

Share Awards

Dividends declared (in dollars per share)

$ 0.55

Dividends declared | $

$ 26,600

Former Employee of RMR LLC

Share Awards

Share repurchases (in shares) | shares

17,448

19,589

Share repurchase price (in dollars per share)

$ 21.61

$ 22.15

Common Shares

Share Awards

Share repurchases (in shares) | shares

18,034

1,129

1,012

13,212

2,459

Trustees | Common Shares

Share Awards

Shares granted (in shares) | shares

3,500

Shares granted (in dollars per share)

$ 26.61

Officers and Certain Employees of RMR LLC | Common Shares

Share Awards

Shares granted (in shares) | shares

108,600

Officer | Common Shares

Share Awards

Shares granted (in dollars per share)

$ 23.04

Business and Property Managem_2

Business and Property Management Agreements with RMR LLC (Details) - RMR LLC $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)employeeagreement	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Related Party Transaction [Line Items]
Number of employees | employee			0
Number of agreements | agreement			2
Incentive fee (reversal)					$ 0
Reimbursement expense	$ 6,437	$ 6,850	$ 18,687	$ 20,007
Net Property Management and Construction Supervision Fees
Related Party Transaction [Line Items]
Related party expense	4,236	5,159	13,237	16,203
Related party transaction amount	$ 5,189	$ 5,622	$ 15,381	$ 16,605

Related Person Transactions (De

Related Person Transactions (Details) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2020USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)agreement	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)
Related Party Transaction [Line Items]
Equity in earnings of an investee		$ (279)	$ (196)	$ (815)	$ (573)
RMR LLC
Related Party Transaction [Line Items]
Number of agreements | agreement				2
Revenue from related party		282	288	$ 836	854
AIC
Related Party Transaction [Line Items]
Carrying value of equity method investments		11		11		$ 298
Distributions in excess of earnings from unconsolidated joint ventures	$ 287
Equity in earnings of an investee		$ 0	$ 83	$ 0	$ 617

Uncategorized Items - opi-20200

Label	Element	Value	[1]
Restricted Cash	us-gaap_RestrictedCash	$ 4,031,000
Restricted Cash	us-gaap_RestrictedCash	$ 12,604,000
[1]	Restricted cash 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.