Office Properties Income Trust (OPI) 10-K 15 Feb 24 2023 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Feb. 14, 2024	Jun. 30, 2023
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2023
Current Fiscal Year End Date	--12-31
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 Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 366.6
Entity Common Stock, Shares Outstanding		48,754,546
Documents Incorporated by Reference	Certain information required by Items 10, 11, 12, 13 and 14 of Part III of this Annual Report on Form 10-K is incorporated by reference to our definitive Proxy Statement for the 2024 Annual Meeting of Shareholders, to be filed with the Securities and Exchange Commission within 120 days after the fiscal year ended December 31, 2023.
Entity Central Index Key	0001456772
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	FY
Amendment Flag	false
Common Shares
Document Information [Line Items]
Title of 12(b) Security	Common Shares of Beneficial Interest
Trading Symbol	OPI
Security Exchange Name	NASDAQ
6.375% Senior Notes Due 2050
Document Information [Line Items]
Title of 12(b) Security	6.375% Senior Notes due 2050
Trading Symbol	OPINL
Security Exchange Name	NASDAQ

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2023
Auditor Information [Abstract]
Auditor Name	Deloitte & Touche LLP
Auditor Location	Boston, Massachusetts
Auditor Firm ID	34

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Real estate properties:
Land	$ 786,310	$ 821,238
Buildings and improvements	3,279,369	3,114,836
Total real estate properties, gross	4,065,679	3,936,074
Accumulated depreciation	(650,179)	(561,458)
Total real estate properties, net	3,415,500	3,374,616
Assets of properties held for sale	37,310	2,516
Investments in unconsolidated joint ventures	18,128	35,129
Acquired real estate leases, net	263,498	369,333
Cash and cash equivalents	12,315	12,249
Restricted cash	14,399	0
Rents receivable	133,264	105,639
Deferred leasing costs, net	86,971	73,098
Other assets, net	8,284	7,397
Total assets	3,989,669	3,979,977
LIABILITIES AND SHAREHOLDERS’ EQUITY
Unsecured revolving credit facility	205,000	195,000
Senior unsecured notes, net	2,195,478	2,187,875
Mortgage notes payable, net	172,131	49,917
Liabilities of properties held for sale	2,525	73
Accounts payable and other liabilities	140,166	140,151
Due to related persons	7,025	6,469
Assumed real estate lease obligations, net	11,665	14,157
Total liabilities	2,733,990	2,593,642
Commitments and contingencies
Shareholders’ equity:
Common shares of beneficial interest, $.01 par value: 200,000,000 shares authorized, 48,755,415 and 48,565,644 shares issued and outstanding, respectively	488	486
Additional paid in capital	2,621,493	2,619,532
Cumulative net income	100,174	169,606
Cumulative common distributions	(1,466,476)	(1,403,289)
Total shareholders’ equity	1,255,679	1,386,335
Total liabilities and shareholders’ equity	$ 3,989,669	$ 3,979,977

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2023	Dec. 31, 2022
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)	200,000,000	200,000,000
Common shares of beneficial interest, shares issued (in shares)	48,755,415	48,565,644
Common shares of beneficial interest, shares outstanding (in shares)	48,755,415	48,565,644

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Rental income	$ 533,553	$ 554,275	$ 576,482
Expenses:
Real estate taxes	62,831	57,844	71,970
Utility expenses	26,778	27,005	25,251
Other operating expenses	109,883	110,366	105,825
Depreciation and amortization	209,254	222,564	241,494
Loss on impairment of real estate	11,299	21,820	62,420
Acquisition and transaction related costs	31,816	292	0
General and administrative	22,731	25,134	26,858
Total expenses	474,592	465,025	533,818
Gain on sale of real estate	3,780	11,001	78,354
Interest and other income	1,039	217	7
Interest expense (including net amortization of debt premiums, discounts and issuance costs of $9,209, $9,134 and $9,771, respectively)	(110,647)	(103,480)	(112,385)
Gain (loss) on early extinguishment of debt	0	682	(14,068)
Loss before income tax expense and equity in net losses of investees	(46,867)	(2,330)	(5,428)
Income tax expense	(351)	(270)	(251)
Equity in net losses of investees	(3,031)	(3,509)	(2,501)
Loss on impairment of equity method investment	(19,183)	0	0
Net loss	$ (69,432)	$ (6,109)	$ (8,180)
Weighted average common shares outstanding (basic) (in shares)	48,389	48,278	48,195
Weighted average common shares outstanding (diluted) (in shares)	48,389	48,278	48,195
Per common share amounts (basic and diluted):
Net loss (basic) (in dollars per share)	$ (1.44)	$ (0.14)	$ (0.17)
Net loss (diluted) (in dollars per share)	$ (1.44)	$ (0.14)	$ (0.17)

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Net amortization of debt premiums, discounts and issuance costs	$ 9,209	$ 9,134	$ 9,771

CONSOLIDATED STATEMENTS OF SHAR

CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Shares	Additional Paid In Capital	Cumulative Net Income	Cumulative Common Distributions
Balance beginning (in shares) at Dec. 31, 2020		48,318,366
Balance beginning at Dec. 31, 2020	$ 1,609,392	$ 483	$ 2,615,305	$ 183,895	$ (1,190,291)
Increase (Decrease) in Shareholders' Equity
Common share grants (in shares)		145,800
Common share grants	2,873	$ 1	2,872
Common share forfeitures and repurchases (in shares)		(38,501)
Common share forfeitures and repurchases	(1,008)		(1,008)
Net loss	(8,180)			(8,180)
Distributions to common shareholders	(106,368)				(106,368)
Balance ending (in shares) at Dec. 31, 2021		48,425,665
Balance ending at Dec. 31, 2021	1,496,709	$ 484	2,617,169	175,715	(1,296,659)
Increase (Decrease) in Shareholders' Equity
Common share grants (in shares)		172,700
Common share grants	2,916	$ 2	2,914
Common share forfeitures and repurchases (in shares)		(32,721)
Common share forfeitures and repurchases	(551)		(551)
Net loss	(6,109)			(6,109)
Distributions to common shareholders	(106,630)				(106,630)
Balance ending (in shares) at Dec. 31, 2022		48,565,644
Balance ending at Dec. 31, 2022	1,386,335	$ 486	2,619,532	169,606	(1,403,289)
Increase (Decrease) in Shareholders' Equity
Common share grants (in shares)		241,800
Common share grants	2,268	$ 2	2,266
Common share forfeitures and repurchases (in shares)		(52,029)
Common share forfeitures and repurchases	(305)		(305)
Net loss	(69,432)			(69,432)
Distributions to common shareholders	(63,187)				(63,187)
Balance ending (in shares) at Dec. 31, 2023		48,755,415
Balance ending at Dec. 31, 2023	$ 1,255,679	$ 488	$ 2,621,493	$ 100,174	$ (1,466,476)

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (69,432)	$ (6,109)	$ (8,180)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation	107,460	96,966	92,266
Net amortization of debt premiums, discounts and issuance costs	9,209	9,134	9,771
Amortization of acquired real estate leases and assumed real estate lease obligations, net	92,805	119,703	144,826
Amortization of deferred leasing costs	10,063	7,994	7,878
Gain on sale of real estate	(3,780)	(11,001)	(78,354)
Loss on impairment of real estate	11,299	21,820	62,420
(Gain) loss on early extinguishment of debt	0	(682)	9,694
Straight line rental income	(26,194)	(10,830)	(15,368)
Other non-cash expenses, net	1,168	1,818	1,782
Equity in net losses of investees	3,031	3,509	2,501
Loss on impairment of equity method investment	19,183	0	0
Change in assets and liabilities:
Rents receivable	(2,376)	10,961	2,663
Deferred leasing costs	(23,510)	(31,621)	(19,769)
Other assets	(1,495)	484	1,538
Accounts payable and other liabilities	13,739	(19,214)	7,151
Due to related persons	556	(318)	673
Net cash provided by operating activities	141,726	192,614	221,492
CASH FLOWS FROM INVESTING ACTIVITIES:
Real estate acquisitions	(2,785)	0	(563,447)
Real estate improvements	(229,004)	(204,104)	(100,141)
Proceeds from sale of properties, net	42,181	203,280	219,980
Contributions to unconsolidated joint ventures	(5,213)	(3,851)	0
Net cash used in investing activities	(194,821)	(4,624)	(442,985)
CASH FLOWS FROM FINANCING ACTIVITIES:
Repayment of mortgage notes payable	(50,000)	(47,617)	(72,541)
Proceeds from issuance of mortgage notes payable	177,320	0	0
Repayment of senior unsecured notes	0	(300,000)	(610,000)
Proceeds from issuance of senior unsecured notes, net	0	0	1,041,809
Borrowings on unsecured revolving credit facility	240,000	385,000	755,000
Repayments on unsecured revolving credit facility	(230,000)	(190,000)	(755,000)
Payment of debt issuance costs	(6,279)	(469)	(2,744)
Repurchase of common shares	(294)	(540)	(1,003)
Distributions to common shareholders	(63,187)	(106,630)	(106,368)
Net cash provided by (used in) financing activities	67,560	(260,256)	249,153
Increase (decrease) in cash, cash equivalents and restricted cash	14,465	(72,266)	27,660
Cash, cash equivalents and restricted cash at beginning of period	12,249	84,515	56,855
Cash, cash equivalents and restricted cash at end of period	26,714	12,249	84,515
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	107,645	104,174	103,200
Income taxes paid	478	352	299
NON-CASH INVESTING ACTIVITIES:
Real estate improvements accrued, not paid	32,231	42,772	18,492
Real estate acquisition	0	0	(13,031)
Capitalized interest	7,634	4,578	795
SUPPLEMENTAL DISCLOSURE OF CASH, CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	12,315	12,249	83,026
Restricted cash	14,399	0	1,489
Total cash, cash equivalents and restricted cash shown in the consolidated statements of cash flows	26,714	12,249	84,515
Unconsolidated Joint Ventures
CASH FLOWS FROM INVESTING ACTIVITIES:
Distributions in excess of earnings	0	51	612
Affiliates Insurance Company
CASH FLOWS FROM INVESTING ACTIVITIES:
Distributions in excess of earnings	$ 0	$ 0	$ 11

Organization

Organization	12 Months Ended
	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Office Properties Income Trust, or OPI, we, us or our, is a real estate investment trust, or REIT, formed in 2009 under Maryland law.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation. These consolidated financial statements include the accounts of us and our subsidiaries, all of which are wholly owned directly or indirectly by us. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated. Real Estate Properties. We record our properties at cost and provide depreciation on real estate investments on a straight line basis over estimated useful lives generally ranging from 7 to 40 years. In some circumstances, we engage independent real estate appraisal firms to provide market information and evaluations which are relevant to our purchase price allocations and determinations of useful lives; however, we are ultimately responsible for the purchase price allocations and determinations of useful lives. We allocate the purchase prices of our properties to land, buildings and improvements based on determinations of the relative fair values of these assets assuming the properties are vacant. We determine the fair value of each property using methods similar to those used by independent appraisers, which may involve estimated cash flows that are based on a number of factors, including capitalization rates and discount rates, among others. We allocate a portion of the purchase price of our properties to above market and below market leases based on the present value (using an interest rate which reflects the risks associated with acquired in place leases at the time each property was acquired by us) of the difference, if any, between (i) the contractual amounts to be paid pursuant to the acquired in place leases and (ii) our estimates of fair market lease rates for the corresponding leases, measured over a period equal to the terms of the respective leases. We allocate a portion of the purchase price to acquired in place leases and tenant relationships based upon market estimates to lease up the property based on the leases in place at the time of purchase. We allocate this aggregate value between acquired in place lease values and tenant relationships based on our evaluation of the specific characteristics of each tenant’s lease. However, we have not separated the value of tenant relationships from the value of acquired in place leases because such value and related amortization expense is immaterial to the accompanying consolidated financial statements. In making these allocations, we consider factors such as estimated carrying costs during the expected lease up periods, including real estate taxes, insurance and other operating income and expenses and costs, such as leasing commissions, legal and other related expenses, to execute similar leases in current market conditions at the time a property was acquired by us. If the value of tenant relationships becomes material in the future, we may separately allocate those amounts and amortize the allocated amounts over the estimated life of the relationships. For transactions that qualify as business combinations, we allocate the excess, if any, of the consideration over the fair value of the assets acquired to goodwill. We amortize capitalized above market lease values (included in acquired real estate leases, net in our consolidated balance sheets) and below market lease values (presented as assumed real estate lease obligations, net in our consolidated balance sheets) as a reduction or increase, respectively, to rental income over the terms of the associated leases. Such amortization resulted in a net increase to rental income of $252 during the year ended December 31, 2023 and net decreases to rental income of $975 and $2,288 during the years ended December 31, 2022 and 2021, respectively. We amortize the value of acquired in place leases (included in acquired real estate leases, net in our consolidated balance sheets), exclusive of the value of above market and below market acquired in place leases, over the terms of the associated leases. Such amortization, which is included in depreciation and amortization expense, amounted to $93,057, $118,728 and $142,538 during the years ended December 31, 2023, 2022 and 2021, respectively. If a lease is terminated prior to its stated expiration, we write off the unamortized amounts relating to that lease. As of December 31, 2023 and 2022, our acquired real estate leases and assumed real estate lease obligations, excluding properties classified as held for sale, were as follows: December 31, 2023 2022 Acquired real estate leases: Capitalized above market lease values $ 14,758 $ 15,792 Less: accumulated amortization (10,876) (9,672) Capitalized above market lease values, net 3,882 6,120 Lease origination value 572,766 728,773 Less: accumulated amortization (313,150) (365,560) Lease origination value, net 259,616 363,213 Acquired real estate leases, net $ 263,498 $ 369,333 Assumed real estate lease obligations: Capitalized below market lease values $ 25,678 $ 27,033 Less: accumulated amortization (14,013) (12,876) Assumed real estate lease obligations, net $ 11,665 $ 14,157 As of December 31, 2023, the weighted average amortization periods for capitalized above market leases, lease origination value and capitalized below market lease values were 3.4 years, 6.5 years and 11.0 years, respectively. Future amortization of net intangible lease assets and liabilities, to be recognized over the current terms of the associated leases as of December 31, 2023 are estimated to be $67,692 in 2024, $48,838 in 2025, $35,068 in 2026, $26,833 in 2027, $14,123 in 2028 and $59,279 thereafter. We regularly evaluate whether events or changes in circumstances have occurred that could indicate an impairment in the value of long lived assets. Impairment indicators may include declining tenant occupancy, lack of progress releasing vacant space, tenant bankruptcies, low long term prospects for improvement in property performance, weak or declining tenant profitability, cash flow or liquidity, our decision to dispose of an asset before the end of its estimated useful life and legislative, market or industry changes that could permanently reduce the value of a property. 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 consideration of impairment upon the events or changes in circumstances described above, we regularly evaluate the remaining useful lives of our long lived assets. If we change our estimate of the remaining useful lives, we allocate the carrying value of the affected assets over their revised remaining useful lives. Cash and Cash Equivalents. We consider highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents. Restricted Cash. 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. Deferred Leasing Costs . Deferred leasing costs include brokerage costs and inducements associated with our entering leases. We amortize deferred leasing costs, which are included in depreciation and amortization expense, and inducements, which are included as a reduction to rental income, on a straight line basis over the terms of the respective leases. Legal costs associated with the execution of our leases are expensed as incurred and included in general and administrative expenses in our consolidated statements of comprehensive income (loss). We recorded amortization of deferred leasing costs of $8,737, $6,869 and $6,691, and reductions to rental income related to the amortization of inducements of $1,326, $1,124 and $1,187 for the years ended December 31, 2023, 2022 and 2021, respectively. Deferred leasing costs, excluding properties classified as held for sale, totaled $113,433 and $94,680 at December 31, 2023 and 2022, respectively, and accumulated amortization of deferred leasing costs totaled $26,462 and $21,582 at December 31, 2023 and 2022, respectively. Future amortization of deferred leasing costs to be recognized during the current terms of our existing leases as of December 31, 2023 are estimated to be $11,807 in 2024, $10,549 in 2025, $9,912 in 2026, $8,919 in 2027, $8,116 in 2028 and $37,668 thereafter. Debt Issuance Costs . Costs related to the issuance or assumption of debt are capitalized and amortized to interest expense over the terms of the respective loans. Debt issuance costs, net of accumulated amortization, for our prior $750,000 unsecured revolving credit facility, or our prior revolving credit facility, are included in other assets in our consolidated balance sheets. As of December 31, 2023 and 2022, debt issuance costs for our prior revolving credit facility were $5,328 and $4,593, respectively, and accumulated amortization of debt issuance costs for our prior revolving credit facility were $5,240 and $4,072, respectively. Debt issuance costs, net of accumulated amortization, for our senior unsecured notes and mortgage notes payable are presented as a direct deduction from the associated debt liability in our consolidated balance sheets. As of December 31, 2023 and 2022, debt issuance costs, net of accumulated amortization, for our senior unsecured notes and mortgage notes payable totaled $16,623 and $13,589, respectively. Future amortization of debt issuance costs to be recognized with respect to our prior revolving credit facility, senior unsecured notes and mortgage notes payable as of December 31, 2023 are estimated to be $3,147 in 2024, $2,573 in 2025, $2,239 in 2026, $1,499 in 2027, $1,231 in 2028 and $6,022 thereafter. Equity Method Investments. As of December 31, 2023, we had noncontrolling ownership interests of 51% and 50% in two unconsolidated joint ventures that owned three properties. The properties owned by these joint ventures are encumbered by an aggregate of $82,000 of mortgage indebtedness. We did not control the activities that are most significant to these joint ventures and, as a result, we accounted for our investments in these joint ventures under the equity method of accounting. See Note 4 for more information regarding our unconsolidated joint ventures. We periodically evaluate our equity method investments 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 and the extent to which the market value of our investment is below our carrying value, the financial condition of our investees, 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 record an impairment charge to adjust the basis of the investment to its estimated fair value. Revenue Recognition. We are a lessor of commercial office properties. Our leases provide our tenants with the contractual right to use and economically benefit from all of the physical space specified in the leases; therefore, we have determined to evaluate our leases as lease arrangements. 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. Allowances for bad debts are recognized as a direct reduction of rental income. Certain of our leases contain non-lease components, such as property level operating expenses and capital expenditures reimbursed by our tenants as well as other required lease payments. We have made the policy election to not separate the lease and non-lease components because (i) the lease components are operating leases and (ii) the timing and pattern of recognition of the non-lease components are the same as those of the lease components. We apply Accounting Standards Codification 842, Leases , to the combined component. Income derived by our leases is recorded in rental income in our consolidated statements of comprehensive income (loss). Certain tenants are obligated to pay directly their obligations under their leases for insurance, real estate taxes and certain other expenses. These obligations, which have been assumed by the tenants under the terms of their respective leases, are not reflected in our consolidated financial statements. To the extent any tenant responsible for any such obligations under the applicable lease defaults on such lease or if it is deemed probable that the tenant will fail to pay for such obligations, we would record a liability for such obligations. See Note 5 for more information regarding our leases. Income Taxes. We have elected to be taxed as a REIT under the United States Internal Revenue Code of 1986, as amended, and, accordingly, we generally will not be subject to federal income taxes provided we distribute our taxable income and meet certain other requirements to qualify for taxation as a REIT. We are, however, subject to certain state and local taxes. Per Common Share Amounts. We calculate basic earnings per common share using the two class method. 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. Use of Estimates. Preparation of these financial statements in conformity with GAAP requires us to make estimates and assumptions that may affect the amounts reported in these consolidated financial statements and related notes. The actual results could differ from these estimates. Significant estimates in the consolidated financial statements include purchase price allocations, useful lives of fixed assets and assessment of impairment of real estate and the related intangibles. Segment Reporting. We operate in one business segment: direct ownership of real estate properties. New Accounting Pronouncements. O n November 27, 2023, the Financial Accounting Standards Board issued Accounting Standards Update No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU No. 2023-07, which requires public entities to: (i) provide disclosures of significant segment expenses and other segment items if they are regularly provided to the Chief Operating Decision Maker, or the CODM, and included in each reported measure of segment profit or loss; (ii) provide all annual disclosures about a reportable segment’s profit or loss and assets currently required by Accounting Standards Codification 280, Segment Reporting, or ASC 280, in interim periods; and (iii) disclose the CODM’s title and position, as well as an explanation of how the CODM uses the reported measures and other disclosures. Public entities with a single reportable segment must apply all the disclosure requirements of ASU No. 2023-07, as well as all the existing segment disclosures under ASC 280. The amendments in ASU No. 2023-07 are incremental to the requirements in ASC 280 and do not change how a public entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments. ASU No. 2023-07 should be applied retrospectively to all prior periods presented in the financial statements and is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. We are currently evaluating the impact ASU No. 2023-07 will have on our consolidated financial statements and disclosures.

Per Common Share Amounts

Per Common Share Amounts	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Per Common Share Amounts	Per Common Share Amounts The calculation of basic and diluted earnings per share is as follows (amounts in thousands, except per share amounts): Year Ended December 31, 2023 2022 2021 Numerators: Net loss $ (69,432) $ (6,109) $ (8,180) Income attributable to unvested participating securities (305) (427) — Net loss used in calculating earnings per share $ (69,737) $ (6,536) $ (8,180) Denominators: Weighted average common shares outstanding - basic and diluted (1) 48,389 48,278 48,195 Net loss per common share - basic and diluted $ (1.44) $ (0.14) $ (0.17) (1) For the years ended December 31, 2023, 2022 and 2021, there were no dilutive common shares. For the year ended December 31, 2021, 34 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	12 Months Ended
	Dec. 31, 2023
Real Estate [Abstract]
Real Estate Properties	Real Estate Properties As of December 31, 2023, our wholly owned properties were comprised of 152 properties containing approximately 20,541,000 rentable square feet, with an undepreciated carrying value of $4,095,010, including $29,331 classified as held for sale. We also had noncontrolling ownership interests of 51% and 50% in two unconsolidated joint ventures that owned three properties containing approximately 468,000 rentable square feet. 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 2024 and 2053. 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 year ended December 31, 2023, we entered into 75 leases for approximately 1,698,000 rentable square feet for a weighted (by rentable square feet) average lease term of 8.5 years and we made commitments of $82,202 for leasing related costs. As of December 31, 2023, we had estimated unspent leasing related obligations of $109,309. Acquisition Activities 2023 Acquisition Activities In December 2023, we acquired a vacant land parcel adjacent to a property we own in Irving, TX for $2,750, excluding acquisition related costs. 2022 Acquisition Activities We did not acquire any properties during the year ended December 31, 2022. 2021 Acquisition Activities During the year ended December 31, 2021, we acquired three properties containing approximately 926,000 rentable square feet for an aggregate purchase price of $576,478, including net purchase price adjustments of $1,761 and acquisition related costs of $1,264. These acquisitions were accounted for as asset acquisitions. We allocated the purchase prices of these acquisitions based on the relative estimated fair values of the acquired assets and assumed liabilities as follows: Acquisition Date Location Number of Properties Rentable Square Feet Purchase Price Land Buildings and Improvements Acquired Real Estate Leases Assumed Real Estate Lease Obligations June 2021 Chicago, IL (1) 1 531,000 $ 368,331 $ 42,935 $ 258,348 $ 76,136 $ (9,088) June 2021 Atlanta, GA 1 346,000 180,602 13,040 135,459 32,103 — August 2021 Boston, MA 1 49,000 27,545 16,103 10,217 1,225 — 3 926,000 $ 576,478 $ 72,078 $ 404,024 $ 109,464 $ (9,088) (1) Purchase price includes an adjustment of $13,031 t o record an estimated real estate tax liability as of the acquisition date. Disposition Activities The sales completed during the years ended December 31, 2023, 2022 and 2021, as presented in the tables 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 consolidated statements of comprehensive income (loss). 2023 Disposition Activities During the year ended December 31, 2023, we sold eight properties containing approximately 553,000 rentable square feet for an aggregate sales price of $44,874, excluding closing costs. Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate January 2023 3 Richmond, VA (2) 89,000 $ 5,350 $ 2,548 April 2023 1 Phoenix, AZ 107,000 4,900 511 June 2023 1 Vernon Hills, IL 100,000 2,825 (2,816) September 2023 1 Windsor Mill, MD 80,000 10,500 244 October 2023 1 Santa Clara, CA 66,000 16,049 705 November 2023 1 Chelmsford, MA 111,000 5,250 2,588 8 553,000 $ 44,874 $ 3,780 (1) Gross sales price is the gross contract price, excluding closing costs. (2) Properties were classified as held for sale as of December 31, 2022. As of December 31, 2023, we had one property located in Chicago, IL containing approximately 248,000 rentable square feet classified as held for sale in our consolidated balance sheets. We recorded an $11,299 loss on impairment of real estate to reduce the carrying value of this property to its estimated fair value less costs to sell as of December 31, 2023. As of February 14, 2024, we have entered into an agreement to sell this property for a sales price of $39,000, excluding closing costs. This pending sale is subject to conditions; accordingly, we cannot be sure that we will complete this sale or that this sale will not be delayed or the terms will not change. 2022 Disposition Activities During the year ended December 31, 2022, we sold 18 properties containing approximately 2,326,000 rentable square feet for an aggregate sales price of $211,020, excluding closing costs. Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate Loss on Impairment of Real Estate January 2022 1 Rockville, MD (2) 129,000 $ 6,750 $ (72) $ — February 2022 2 Chesapeake, VA (2) 172,000 18,945 2,296 — March 2022 1 Milwaukee, WI (2) 29,000 3,775 (75) — May 2022 1 Holtsville, NY 264,000 28,500 1,900 — June 2022 1 Fairfax, VA 184,000 19,750 (13,537) — July 2022 1 Houston, TX 206,000 9,800 (135) 15,278 August 2022 3 Birmingham, AL 448,000 16,050 (265) 3,709 August 2022 1 Erlanger, KY 86,000 2,600 135 2,184 September 2022 2 Chesapeake, VA 214,000 24,000 62 649 September 2022 2 Everett, WA 112,000 31,500 11,959 — September 2022 1 Salem, OR 233,000 34,250 5,369 — November 2022 1 Kapolei, HI (3) 109,000 4,000 2,504 — November 2022 1 Englewood, CO 140,000 11,100 860 — 18 2,326,000 $ 211,020 $ 11,001 $ 21,820 (1) Gross sales price is the gross contract price, excluding closing costs. (2) Properties were classified as held for sale as of December 31, 2021. (3) Property is a leasable land parcel. 2021 Disposition Activities During the year ended December 31, 2021, we sold six properties, a warehouse facility and two vacant land parcels containing approximately 2,565,000 rentable square feet for an aggregate sales price of $226,915, excluding closing costs. Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate Loss on Impairment of Real Estate January 2021 — Kansas City, MO (2)(3) 10,000 $ 845 $ (63) $ — January 2021 1 Richmond, VA (2) 311,000 130,000 54,181 — April 2021 1 Huntsville, AL 1,371,000 39,000 — 5,383 July 2021 1 Fresno, CA 532,000 6,000 — 33,902 July 2021 1 Liverpool, NY 38,000 650 31 — August 2021 1 Memphis, TN 205,000 15,270 287 — September 2021 1 Stoneham, MA 98,000 6,650 (282) 5,911 October 2021 — Sterling, VA (4) — 28,500 24,200 — 6 2,565,000 $ 226,915 $ 78,354 $ 45,196 (1) Gross sales price is the gross contract price, excluding closing costs. (2) Properties were classified as held for sale as of December 31, 2020. (3) Consists of a warehouse facility. (4) Consists of two vacant land parcels. We also recorded a $10,658 loss on impairment of real estate to reduce the carrying value of three properties that were classified as held for sale to their estimated fair values less costs to sell as of September 30, 2021. Subsequently, we removed these properties from held for sale status due to a change of plan for sale and recorded an impairment adjustment of $425 to increase the carrying value of these properties to their estimated fair value as of December 31, 2021. In addition, we recorded a $6,991 loss on impairment of real estate to reduce the carrying value of two properties that were classified as held for sale as of December 31, 2021 and subsequently sold in 2022. Unconsolidated Joint Ventures As of December 31, 2023, we owned interests in two joint ventures that owned three properties. We accounted for these investments under the equity method of accounting. As of December 31, 2023 and 2022, our investments in unconsolidated joint ventures consisted of the following: OPI Ownership OPI Carrying Value of Investments at December 31, Number of Properties Location Rentable Square Feet Joint Venture 2023 2022 Prosperity Metro Plaza 51% $ 18,128 $ 19,237 2 Fairfax, VA 346,000 1750 H Street, NW 50% — 15,892 1 Washington, D.C. 122,000 Total $ 18,128 $ 35,129 3 468,000 In October 2023, our joint venture partner in our 1750 H Street, NW joint venture failed to fund a $600 capital call and was in default of the joint venture agreement as of December 31, 2023. During our periodic evaluation of our equity method investments for impairment, we determined that the estimated fair value of our investment in our 1750 H Street, NW joint venture was lower than our carrying value and the decline was other than temporary based on current market conditions and the default of our joint venture partner. As a result, we recorded a loss on impairment of equity method investment of $19,183 during the year ended December 31, 2023 to fully write off its carrying value. 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 December 31, 2023 and 2022 (2) Prosperity Metro Plaza 4.09% 12/1/2029 $ 50,000 1750 H Street, NW (3) 3.69% 8/1/2027 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 did not own. None of the debt is recourse to us. (3) In July 2023, the maturity date of this mortgage loan was extended by three years at the same interest rate. As of December 31, 2023, the unamortized basis difference of our Prosperity Metro Plaza joint venture of $701 was primarily attributable to the difference between the amount we paid to purchase our interest in this joint venture, including transaction costs, and the historical carrying value of the net assets of this joint venture. This difference is being amortized over the remaining useful life of the related property and the resulting amortization expense is included in equity in net losses of investees in our consolidated statements of comprehensive income (loss). As of December 31, 2023, there was no unamortized basis difference for our 1750 H Street, NW joint venture.

Leases

Leases	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Leases	Leases Rental income from operating leases, including 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. We increased rental income by $26,194, $10,830 and $15,368 to record revenue on a straight line basis during the years ended December 31, 2023, 2022 and 2021, respectively. Rents receivable, excluding properties classified as held for sale, include $112,440 and $86,305 of straight line rent receivables at December 31, 2023 and 2022, 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 $88,173, $83,103 and $85,107 for the years ended December 31, 2023, 2022 and 2021, respectively, of which tenant reimbursements totaled $82,885, $78,388 and $81,295, respectively. The following operating lease maturity analysis presents the future contractual lease payments to be received by us through 2053 as of December 31, 2023: Year Amount 2024 $ 378,748 2025 339,500 2026 310,205 2027 281,109 2028 243,928 Thereafter 1,428,379 Total $ 2,981,869 As of December 31, 2023, tenants representing approximately 1.8% of our total operating lease maturities had exercisable rights to terminate their leases before the stated terms of their leases expire. In 2024, 2025, 2026, 2027, 2028, 2029, 2030, 2031, 2032, 2034, 2035, 2036, 2037 and 2040, early termination rights become exercisable by other tenants who represented an additional approximatel y 1.4%, 2.5%, 2.4%, 2.0%, 6.1%, 2.0%, 2.6%, 1.0%, 0.8%, 1.4%, 4.4%, 0.6%, 0.6% and 2.3% of our t otal operating lease maturities, respectively. 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 a remote contingency based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis. As of December 31, 2023, eight of our tenants had the right to terminate their leases if the respective legislature or other funding authority does not appropriate the funding necessary for the tenant to meet its obligation. These eight tenants represented approximately 3.9% of our total operating lease maturities as of December 31, 2023. Leases where we are the lessee. We had one lease where we were the lessee which expired on January 31, 2021. We subleased a portion of the space, which sublease also expired on January 31, 2021. Rent expense incurred under the lease, net of sublease revenue, was $79 for the year ended December 31, 2021.
Leases	Leases Rental income from operating leases, including 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. We increased rental income by $26,194, $10,830 and $15,368 to record revenue on a straight line basis during the years ended December 31, 2023, 2022 and 2021, respectively. Rents receivable, excluding properties classified as held for sale, include $112,440 and $86,305 of straight line rent receivables at December 31, 2023 and 2022, 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 $88,173, $83,103 and $85,107 for the years ended December 31, 2023, 2022 and 2021, respectively, of which tenant reimbursements totaled $82,885, $78,388 and $81,295, respectively. The following operating lease maturity analysis presents the future contractual lease payments to be received by us through 2053 as of December 31, 2023: Year Amount 2024 $ 378,748 2025 339,500 2026 310,205 2027 281,109 2028 243,928 Thereafter 1,428,379 Total $ 2,981,869 As of December 31, 2023, tenants representing approximately 1.8% of our total operating lease maturities had exercisable rights to terminate their leases before the stated terms of their leases expire. In 2024, 2025, 2026, 2027, 2028, 2029, 2030, 2031, 2032, 2034, 2035, 2036, 2037 and 2040, early termination rights become exercisable by other tenants who represented an additional approximatel y 1.4%, 2.5%, 2.4%, 2.0%, 6.1%, 2.0%, 2.6%, 1.0%, 0.8%, 1.4%, 4.4%, 0.6%, 0.6% and 2.3% of our t otal operating lease maturities, respectively. 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 a remote contingency based on both our historical experience and our assessments of the likelihood of lease cancellation on a separate lease basis. As of December 31, 2023, eight of our tenants had the right to terminate their leases if the respective legislature or other funding authority does not appropriate the funding necessary for the tenant to meet its obligation. These eight tenants represented approximately 3.9% of our total operating lease maturities as of December 31, 2023. Leases where we are the lessee. We had one lease where we were the lessee which expired on January 31, 2021. We subleased a portion of the space, which sublease also expired on January 31, 2021. Rent expense incurred under the lease, net of sublease revenue, was $79 for the year ended December 31, 2021.

Business and Property Managemen

Business and Property Management Agreements with RMR	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Business and Property Management Agreements with RMR	Business and Property Management Agreements with RMR We have no employees. The personnel and various services we require to operate our business are provided to us by The RMR Group LLC, or RMR. We have two agreements with RMR 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. Management Agreements with RMR . Our management agreements with RMR provide for an annual base management fee, an annual incentive management fee and property management and construction supervision fees, payable in cash, among other terms: • Base Management Fee. The annual base management fee payable to RMR by us for each applicable period is equal to the lesser of: • the sum of (a) 0.5% of the average aggregate historical cost of the real estate assets acquired from a REIT to which RMR provided business management or property management services, or the Transferred Assets, plus (b) 0.7% of the average aggregate historical cost of our real estate investments excluding the Transferred Assets up to $250,000, plus (c) 0.5% of the average aggregate historical cost of our real estate investments excluding the Transferred Assets exceeding $250,000; and • the sum of (a) 0.7% of the average closing price per share of our common shares on the stock exchange on which such shares are principally traded during such period, multiplied by the average number of our common shares outstanding during such period, plus the daily weighted average of the aggregate liquidation preference of each class of our preferred shares outstanding during such period, plus the daily weighted average of the aggregate principal amount of our consolidated indebtedness during such period, or, together, our Average Market Capitalization, up to $250,000, plus (b) 0.5% of our Average Market Capitalization exceeding $250,000. The average aggregate historical cost of our real estate investments includes our consolidated assets invested, directly or indirectly, in equity interests in or loans secured by real estate and personal property owned in connection with such real estate (including acquisition related costs and costs which may be allocated to intangibles or are unallocated), all before reserves for depreciation, amortization, impairment charges or bad debts or other similar non-cash reserves. • Incentive Management Fee . The incentive management fee which may be earned by RMR for an annual period is calculated as follows: • An amount, subject to a cap based on the value of our common shares outstanding, equal to 12% of the product of: • our equity market capitalization on the last trading day of the year immediately prior to the relevant three • the amount (expressed as a percentage) by which the total return per share, as defined in the business management agreement and further described below, of our common shareholders (i.e., share price appreciation plus dividends) exceeds the total shareholder return of the applicable index, or the benchmark return per share, for the relevant measurement period. The MSCI U.S. REIT/Office REIT Index is the benchmark index for periods on and after August 1, 2021, and the SNL U.S. REIT Office Index is the benchmark index for periods prior to August 1, 2021. For purposes of the total return per share of our common shareholders, share price appreciation for a measurement period is determined by subtracting (1) the closing price of our common shares on The Nasdaq Stock Market LLC, or Nasdaq, on the last trading day of the year immediately before the first year of the applicable measurement period, or the initial share price, from (2) the average closing price of our common shares on the 10 consecutive trading days having the highest average closing prices during the final 30 trading days in the last year of the measurement period. • The calculation of the incentive management fee (including the determinations of our equity market capitalization, initial share price and the total return per share of our common shareholders) is subject to adjustments if we issue or repurchase our common shares, or if our common shares are forfeited, during the measurement period. • No incentive management fee is payable by us unless our total return per share during the measurement period is positive. • The measurement periods are three year • If our total return per share exceeds 12% per year in any measurement period, the benchmark return per share is adjusted to be the lesser of the total shareholder return of the applicable index for such measurement period and 12% per year, or the adjusted benchmark return per share. In instances where the adjusted benchmark return per share applies, the incentive management fee will be reduced if our total return per share is between 200 basis points and 500 basis points below the applicable index in any year by a low return factor, as defined in the business management agreement, and there will be no incentive management fee paid if, in these instances, our total return per share is more than 500 basis points below the applicable index in any year, determined on a cumulative basis (i.e., between 200 basis points and 500 basis points per year multiplied by the number of years in the measurement period and below the applicable market index). • The incentive management fee is subject to a cap. The cap is equal to the value of the number of our common shares which would, after issuance, represent 1.5% of the number of our common shares then outstanding multiplied by the average closing price of our common shares during the 10 consecutive trading days having the highest average closing prices during the final 30 trading days of the relevant measurement period. • Incentive management fees we paid to RMR for any period may be subject to “clawback” if our financial statements for that period are restated due to material non-compliance with any financial reporting requirements under the securities laws as a result of the bad faith, fraud, willful misconduct or gross negligence of RMR and the amount of the incentive management fee we paid was greater than the amount we would have paid based on the restated financial statements. Pursuant to our business management agreement with RMR, we recognized net business management fees of $14,751, $17,376 and $18,637 for the years ended December 31, 2023, 2022 and 2021, respectively. The net business management fees we recognized are included in general and administrative expenses in our consolidated statements of comprehensive income (loss) for these periods. The net business management fees we recognized for each of the years ended December 31, 2023, 2022 and 2021 reflect a reduction of $603, for the amortization of the liability we recorded in connection with our former investment in RMR Inc. We did not incur any incentive management fee pursuant to our business management agreement for the years ended December 31, 2023, 2022 or 2021. • Property Management and Construction Supervision Fees . The property management fees payable to RMR by us for each applicable period are equal to 3.0% of gross collected rents and the construction supervision fees payable to RMR by us for each applicable period are equal to 5.0% of construction costs. Pursuant to our property management agreement with RMR, we recognized aggregate net property management and construction supervision fees of $23,280, $25,756 and $21,103 for each of the years ended December 31, 2023, 2022 and 2021, respectively. The net property management and construction supervision fees we recognized for the years ended December 31, 2023, 2022 and 2021 reflect a reduction of $484 for each of those years for the amortization of the liability we recorded in connection with our former investment in RMR Inc. For the years ended December 31, 2023, 2022 and 2021, $14,890, $15,839 and $16,507, respectively, of the total net property management and construction supervision fees were expensed to other operating expenses in our consolidated statements of income (loss) and $8,390, $9,917 and $4,596, respectively, were capitalized as building improvements in our consolidated balance sheets. The amounts capitalized are being depreciated over the estimated useful lives of the related capital assets. • Expense Reimbursement . We are generally responsible for all of our operating expenses, including certain expenses incurred or arranged by RMR on our behalf. We are generally not responsible for payment of RMR’s employment, office or administrative expenses incurred to provide management services to us, except for the employment and related expenses of RMR’s employees assigned to work exclusively or partly at our properties, our share of the wages, benefits and other related costs of RMR’s centralized accounting personnel, our share of RMR’s costs for providing our internal audit function and as otherwise agreed. Our property level operating expenses are generally incorporated into rents charged to our tenants, including certain payroll and related costs incurred by RMR. We reimbursed RMR $25,872 , $24,371 and $24,766 for these expenses and costs for each of the years ended December 31, 2023, 2022 and 2021, respectively. We included these amounts in other operating expenses and general and administrative expense, as applicable, for these periods. • Term . Our management agreements with RMR have terms that end on December 31, 2043, and automatically extend on December 31st of each year for an additional year, so that the terms of our management agreements thereafter end on the 20th anniversary of the date of the extension. • Termination Rights . We have the right to terminate one or both of our management agreements with RMR: (i) at any time on 60 days’ written notice for convenience, (ii) immediately on written notice for cause, as defined therein, (iii) on written notice given within 60 days after the end of an applicable calendar year for a performance reason, as defined therein, and (iv) by written notice during the 12 months following a change of control of RMR, as defined therein. RMR has the right to terminate the management agreements for good reason, as defined therein. • Termination Fee . If we terminate one or both of our management agreements with RMR for convenience, or if RMR terminates one or both of our management agreements for good reason, we have agreed to pay RMR a termination fee in an amount equal to the sum of the present values of the monthly future fees, as defined therein, for the terminated management agreement(s) for the term that was remaining prior to such termination, which, depending on the time of termination, would be between 19 and 20 years. If we terminate one or both of our management agreements with RMR for a performance reason, we have agreed to pay RMR the termination fee calculated as described above, but assuming a 10-year term was remaining prior to the termination. We are not required to pay any termination fee if we terminate our management agreements with RMR for cause or as a result of a change of control of RMR. • Transition Services . RMR has agreed to provide certain transition services to us for 120 days following an applicable termination by us or notice of termination by RMR, including cooperating with us and using commercially reasonable efforts to facilitate the orderly transfer of the management and real estate investment services provided under our business management agreement and to facilitate the orderly transfer of the management of the managed properties under our property management agreement, as applicable. • Vendors . Pursuant to our management agreements with RMR, RMR may from time to time negotiate on our behalf with certain third party vendors and suppliers for the procurement of goods and services to us. As part of this arrangement, we may enter agreements with RMR and other companies to which RMR or its subsidiaries provide management services for the purpose of obtaining more favorable terms from such vendors and suppliers. • Investment Opportunities . Under our business management agreement with RMR, we acknowledge that RMR may engage in other activities or businesses and act as the manager to any other person or entity (including other REITs) even though such person or entity has investment policies and objectives similar to ours and we are not entitled to preferential treatment in receiving information, recommendations and other services from RMR. Management Agreements between our Joint Ventures and RMR . RMR provides management services to our two unconsolidated joint ventures. We are not obligated to pay management fees to RMR under our management agreements with RMR for the services it provides regarding the joint ventures. The joint ventures pay management fees directly to RMR.

Related Person Transactions

Related Person Transactions	12 Months Ended
	Dec. 31, 2023
Related Party Transactions [Abstract]
Related Person Transactions	Related Person Transactions We have relationships and historical and continuing transactions with RMR, RMR Inc. and others related to them, including other companies to which RMR or its subsidiaries provide management services and some of which have trustees, directors or officers who are also our Trustees or officers. RMR is a majority owned subsidiary of RMR Inc. The Chair of our Board of Trustees and one of our Managing Trustees, Adam D. Portnoy, is the sole trustee, an officer and the controlling shareholder of ABP Trust, which is the controlling shareholder of RMR Inc., the chair of the board of directors, a managing director, the president and chief executive officer of RMR Inc. and an officer and employee of RMR. Jennifer Clark, our other Managing Trustee, is a managing director and the executive vice president, general counsel and secretary of RMR Inc., an officer and employee of RMR and an officer of ABP Trust. Each of our officers is also an officer and employee of RMR. Some of our Independent Trustees also serve as independent trustees of other public companies to which RMR or its subsidiaries provide management services. Mr. Portnoy serves as chair of the boards and as a managing trustee of these public companies. Other officers of RMR, including Ms. Clark, serve as managing trustees or officers of certain of these companies. Our Manager, RMR . We have two agreements with RMR to provide management services to us. RMR also provides management services to our unconsolidated joint ventures. See Note 6 for more information regarding our and our unconsolidated joint ventures’ management agreements with RMR. Leases with RMR . We lease office space to RMR in certain of our properties for RMR’s property management offices. Pursuant to our lease agreements with RMR, we recognized rental income from RMR for leased office space of $851, $1,126 and $1,138 for the years ended December 31, 2023, 2022 and 2021, respectively. Our office space leases with RMR are terminable by RMR if our management agreements with RMR are terminated. Share Awards to RMR Employees . As described further in Note 11, we award shares to our officers and other employees of RMR annually. Generally, one fifth of these awards vest on the grant date and one fifth vests on each of the next four Sonesta . In June 2021, we entered into a 30-year lease agreement with a subsidiary of Sonesta International Hotels Corporation, or Sonesta, in connection with the redevelopment of an office property we own in Washington, D.C. as a mixed-use property. Sonesta’s lease commenced in August 2023 and is for the full-service hotel component of the property that includes approximately 230,000 rentable square feet, which represents approximately 55% of the total square feet upon completion of the redevelopment. Sonesta has two options to extend the term for 10 years each. Pursuant to the lease agreement, Sonesta will pay us annual base rent of approximately $6,436 beginning 18 months after the lease commenced. The annual base rent will increase by 10% every five years throughout the term. Sonesta is also obligated to pay its pro rata share of the operating costs for the property. As of December 31, 2023, we have paid approximately $66,000 of tenant improvement costs for the build out of the hotel space pursuant to the lease agreement. Mr. Portnoy is a director and controlling shareholder of Sonesta and Ms. Clark is a director of Sonesta. Another officer and employee of RMR is a director and president and chief executive officer of Sonesta. Terminated Merger Agreement with DHC . On April 11, 2023, we and Diversified Healthcare Trust, or DHC, entered into an Agreement and Plan of Merger, or the Merger Agreement, pursuant to which we and DHC had agreed that DHC would merge with and into us, with us as the surviving entity in the merger, subject to the terms and conditions of the Merger Agreement. On September 1, 2023, we and DHC mutually agreed to terminate the Merger Agreement and entered into a termination agreement, or the Termination Agreement. The mutual termination of the Merger Agreement was separately recommended by our and DHC’s respective Special Committees of each Board of Trustees, and approved by our and DHC’s respective Board of Trustees. Neither we nor DHC were required to pay any termination fee as a result of the mutual decision to terminate the Merger Agreement. We and DHC bore our and its respective costs and expenses related to the Merger Agreement and the transactions contemplated thereby in accordance with the terms of the Merger Agreement. We recorded $31,491 of expenses during the year ended December 31, 2023 related to the potential merger with DHC, which is included in acquisition and transaction related costs in our consolidated statement of comprehensive income (loss). Contemporaneously with the execution of the Merger Agreement, on April 11, 2023, we and our manager, RMR, entered into a Third Amended and Restated Property Management Agreement, or the Amended Property Management Agreement. The effectiveness of the Amended Property Management Agreement was conditioned upon the consummation of the merger. Since the merger was not consummated, the Amended Property Management Agreement did not become effective and the Second Amended and Restated Property Management Agreement between us and RMR remains in effect.

Concentration

Concentration	12 Months Ended
	Dec. 31, 2023
Risks and Uncertainties [Abstract]
Concentration	Concentration Tenant and Credit Concentration As of December 31, 2023, 2022 and 2021, the U.S. government and certain state and other government tenants combined were responsible for approximately 27.5%, 28.5% and 28.9%, respectively, of our annualized rental income. The U.S. government is our largest tenant by annualized rental income and represented approximately 19.5%, 19.7%, and 19.5% of our annualized rental income as of December 31, 2023, 2022 and 2021, respectively. 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. Geographic Concentration As of December 31, 2023, our 152 wholly owned properties were located in 30 states and the District of Columbia. Properties located in California, Virginia, Illinois, District of Columbia and Texas were responsible for approximately 11.8%, 11.6%, 10.6%, 9.3%, and 8.8% of our annualized rental income as of December 31, 2023, respectively.

Indebtedness

Indebtedness	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Indebtedness	Indebtedness As of December 31, 2023 and 2022, our outstanding indebtedness consisted of the following: December 31, 2023 2022 Revolving credit facility, due in 2024 $ 205,000 $ 195,000 Mortgage note payable, 3.700% interest rate, due in 2023 (1) — 50,000 Senior unsecured notes, 4.250% interest rate, due in 2024 350,000 350,000 Senior unsecured notes, 4.500% interest rate, due in 2025 650,000 650,000 Senior unsecured notes, 2.650% interest rate, due in 2026 300,000 300,000 Senior unsecured notes, 2.400% interest rate, due in 2027 350,000 350,000 Mortgage note payable, 8.272% interest rate, due in 2028 42,700 — Mortgage note payable, 8.139% interest rate, due in 2028 26,340 — Mortgage note payable, 7.671% interest rate, due in 2028 54,300 — Senior unsecured notes, 3.450% interest rate, due in 2031 400,000 400,000 Mortgage note payable, 7.210% interest rate, due in 2033 30,680 — Mortgage note payable, 7.305% interest rate, due in 2033 8,400 — Mortgage note payable, 7.717% interest rate, due in 2033 14,900 — Senior unsecured notes, 6.375% interest rate, due in 2050 162,000 162,000 2,594,320 2,457,000 Unamortized debt premiums, discounts and issuance costs (21,711) (24,208) $ 2,572,609 $ 2,432,792 (1) This mortgage note was repaid at maturity in June 2023. In January 2024, we entered into an amended and restated credit agreement, or our credit agreement, governing a new $325,000 secured revolving credit facility and a $100,000 secured term loan. Our credit agreement replaced our prior revolving credit facility, which had a maturity date of January 31, 2024. As collateral for all loans and other obligations under our credit agreement, certain of our subsidiaries pledged all of their respective equity interests in certain of our direct and indirect property owning subsidiaries, and our pledged subsidiaries provided first mortgage liens on 19 properties that had an undepreciated carrying value, including lease intangibles, other assets and other liabilities, of $941,937 as of December 31, 2023. We can borrow, repay, and reborrow funds available under our revolving credit facility until maturity, and no principal repayments on borrowings under our credit agreement are due until maturity. The maturity date of our credit agreement is January 29, 2027 and, subject to the payment of an extension fee and meeting certain other requirements, we can extend the stated maturity date of our revolving credit facility by one year. Our credit agreement contains a number of covenants, including covenants that require us to maintain certain financial ratios, restrict our ability to incur additional debt in excess of calculated amounts and, subject to limited exceptions, restrict our ability to increase our distribution rate above the current level of $0.01 per common share per quarter and enter into share repurchases. Availability of borrowings under our credit agreement is subject to ongoing minimum performance and market values of the 19 collateral properties, our satisfying certain financial covenants and other credit facility conditions. Interest payable on borrowings under our credit agreement is at a rate of the secured overnight financing rate, or SOFR, plus a margin of 350 basis points. We are also required to pay an unused facility fee on the amount of total lending commitments, which was 35 basis points per annum at February 14, 2024. As of February 14, 2024, we had $132,000 outstanding under our revolving credit facility, $100,000 outstanding under our term loan and $193,000 available for borrowing under our revolving credit facility. Prior Revolving Credit Facility Under our prior revolving credit facility, we were required to pay interest at a rate of SOFR plus a premium, which was 145 basis points per annum at December 31, 2023, on the amount outstanding under our prior revolving credit facility, as well as a facility fee on the total amount of lending commitments, which was 30 basis points per annum at December 31, 2023. As of December 31, 2023 and 2022, the annual interest rate payable on borrowings under our prior revolving credit facility was 6.9% and 5.4%, respectively. The weighted average annual interest rate for borrowings under our prior revolving credit facility was 6.5%, 4.0% and 1.2% for the years ended December 31, 2023, 2022 and 2021, respectively. As of December 31, 2023, we had $205,000 outstanding under our prior revolving credit facility. Our revolving credit facility is governed by a credit agreement with a syndicate of institutional lenders. Our credit agreement and senior 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 RMR ceasing to act as our business and property manager. Our credit agreement and our senior notes indentures and their supplements also contain, and our prior revolving credit facility contained, 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 increase our distribution rate above the current level of $0.01 per common share per quarter. We believe we were in compliance with the terms and conditions of the respective covenants under our credit agreement and our senior notes indentures and their supplements at December 31, 2023. Mortgage Note Issuances During the year ended December 31, 2023, we issued six fixed rate, interest-only mortgage notes as summarized in the following table: Issuance Date Secured By Principal Balance (1) Interest Rate Maturity Net Book Value of Collateral as of December 31, 2023 May 2023 (2) One property $ 30,680 7.210% 7/1/2033 $ 36,807 June 2023 One property 26,340 8.139% 7/1/2028 52,342 June 2023 One property 42,700 8.272% 7/1/2028 42,834 June 2023 One property 8,400 7.305% 7/1/2033 19,035 August 2023 One property 14,900 7.717% 9/1/2033 23,908 September 2023 Two properties 54,300 7.671% 10/6/2028 64,828 Total / Weighted Average $ 177,320 7.792% $ 239,754 (1) Our mortgage notes are non-recourse, subject to certain limited exceptions and do not contain any material financial covenants. (2) Requires interest-only payments through May 2028, at which time principal and interest payments are due monthly through the maturity date. Mortgage Note Repayment In June 2023, we repaid at maturity, a mortgage note secured by one property with an outstanding principal balance of $50,000, an annual interest rate of 3.70%. Senior Secured Notes Issuance In February 2024, we issued $300,000 of 9.000% senior secured notes due 2029, or the 2029 Notes. The aggregate net proceeds from the offering of the 2029 Notes were $271,500, after initial purchaser discounts and other estimated offering expenses. The 2029 Notes are fully and unconditionally guaranteed on a joint, several and senior secured basis by certain of our subsidiaries and secured by a pledge of all of the respective equity interests of the subsidiary guarantors and first mortgage liens on 17 properties with an undepreciated carrying value, including lease intangibles, other assets and other liabilities, of $574,291 as of December 31, 2023. The 2029 Notes require semi-annual payments of interest only and are prepayable, at par plus accrued interest, after March 31, 2028. Senior Unsecured Notes Redemption In February 2024, we issued a notice of early redemption, at par plus accrued interest, of all of our $350,000 of 4.25% senior unsecured notes due 2024. The redemption is expected to take place in March 2024 and is conditioned upon our borrowing an amount under our revolving credit facility sufficient, together with the net proceeds from the offering of the 2029 Notes, to pay the redemption price on or prior to the redemption date. The required principal payments due during the next five years and thereafter under all our outstanding consolidated debt as of December 31, 2023 were as follows: Year Principal Payment 2024 $ 555,000 2025 650,000 2026 300,000 2027 350,000 2028 123,487 Thereafter 615,833 Total $ 2,594,320 (1) (1) Total consolidated debt outstanding as of December 31, 2023, net of unamortized premiums, discounts and issuance costs totaling $21,711, was $2,572,609. None of our unsecured debt obligations require principal or sinking fund payments prior to their maturity dates. We currently do not have sufficient sources of liquidity to repay our $650,000 senior unsecured notes due 2025 and are evaluating market-based alternatives to obtain debt financing. Based on the significant number of unencumbered properties in our portfolio, our successful history of obtaining debt financings and our current financing metrics, we believe it is probable that we can obtain new debt financing that will allow us satisfy the 2025 unsecured notes as they become due. We have also engaged Moelis & Company LLC as our financial advisor to assist in evaluating our options to address our upcoming debt maturities.

Fair Value of Assets and Liabil

Fair Value of Assets and Liabilities	12 Months Ended
	Dec. 31, 2023
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 December 31, 2023, categorized by 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) $ 39,000 $ — $ 39,000 $ — (1) We recorded an impairment charge of $11,299 to reduce the carrying value of one property in our consolidated balance sheet to its estimated fair value less estimated costs to sell of $1,777, based on a negotiated sales price with a third party buyer (Level 2 input as defined in the fair value hierarchy under GAAP). See Note 4 for more information. We recorded an impairment charge of $19,183 to fully write off our equity method investment in our 1750 H NW joint venture, based on our estimates of fair value of the investment which reflects implied pricing based on ongoing negotiations with the lender to this joint venture regarding the property (a Level 3 input as defined in the fair value hierarchy under GAAP). See Note 4 for more information. In addition to the assets described above, our financial instruments include our cash and cash equivalents, restricted cash, rents receivable, accounts payable, a revolving credit facility, senior notes, mortgage notes payable, amounts due to related persons, other accrued expenses and security deposits. At December 31, 2023 and 2022, the fair values of our financial instruments approximated their carrying values in our consolidated financial statements, due to their short term nature or floating interest rates, except as follows: As of December 31, 2023 As of December 31, 2022 Financial Instrument Carrying Value (1) Fair Value Carrying Value (1) Fair Value Senior unsecured notes, 4.25% interest rate, due in 2024 $ 349,144 $ 331,510 $ 346,863 $ 331,601 Senior unsecured notes, 4.50% interest rate, due in 2025 646,266 510,445 642,818 589,388 Senior unsecured notes, 2.650% interest rate, due in 2026 298,464 185,934 297,839 232,770 Senior unsecured notes, 2.400% interest rate, due in 2027 348,086 196,147 347,466 256,606 Senior unsecured notes, 3.450% interest rate, due in 2031 396,614 199,060 396,178 268,004 Senior unsecured notes, 6.375% interest rate, due in 2050 156,904 83,916 156,711 113,075 Mortgage notes payable (2)(3) 172,131 179,813 49,917 49,099 Total $ 2,367,609 $ 1,686,825 $ 2,237,792 $ 1,840,543 (1) Includes unamortized debt premiums, discounts and issuance costs totaling $21,711 and $24,208 as of December 31, 2023 and 2022, respectively. (2) Balances as of December 31, 2022 include a mortgage note secured by one property with an outstanding principal balance of $50,000 that was repaid in June 2023. (3) Balances as of December 31, 2023 include six mortgage notes issued during the year ended December 31, 2023 with an aggregate principal balance of $177,320. We estimated the fair values of our senior unsecured notes (except for our senior unsecured notes due 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 values of our senior unsecured notes due 2050 based on the closing price on 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 values may differ materially from the actual fair values.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Shareholders' Equity	Shareholders’ Equity Share Awards We have common shares available for issuance under the terms of our Amended and Restated 2009 Incentive Share Award Plan, or the 2009 Plan. During the years ended December 31, 2023, 2022 and 2021, we awarded to our officers and other employees of RMR annual share awards of 210,300, 141,200 and 117,800 of our common shares, respectively, valued at $1,211, $2,470 and $2,994, in aggregate, respectively. We also awarded each of our then Tr ustees 3,500 of our common shares in each of 2023, 2022 and 2021 as part of their annual compensation. These awards had aggregate values of $249 ( $28 per Trustee), $593 ($66 p er Trustee) and $837 ($105 per Trustee) in 2023, 2022 and 2021, respectively. The values of the share awards were based upon the closing price of our common shares trading on Nasdaq on the date of award. The common shares awarded to our officers and certain other employees of RMR vest in five equal annual installments beginning on the date of award. The common shares awarded to our Trustees vest immediately. We recognize share forfeitures as they occur and include the value of awarded shares in general and administrative expenses ratably over the vesting period. A summary of shares awarded, forfeited, vested and unvested under the terms of the 2009 Plan for the years ended December 31, 2023, 2022 and 2021, is as follows: 2023 2022 2021 Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 231,301 $ 21.47 182,224 $ 26.23 157,521 $ 29.26 Awarded 241,800 $ 6.04 172,700 $ 17.74 145,800 $ 26.28 Forfeited (3,700) $ 17.31 (1,900) $ 25.97 (700) $ 25.97 Vested (180,720) $ 16.00 (121,723) $ 23.24 (120,397) $ 30.24 Unvested at end of year 288,681 $ 12.01 231,301 $ 21.47 182,224 $ 26.23 The 288,681 unvested shares as of December 31, 2023 are scheduled to vest as follows: 98,241 shares in 2024, 83,620 shares in 2025, 65,160 shares in 2026 and 41,660 shares in 2027. As of December 31, 2023, the estimated future compensation expense for the unvested shares was $3,042. The weighted average period over which the compensation expense will be recorded is approximately 23 months. During the years ended December 31, 2023, 2022 and 2021, we recorded $2,257, $2,905 and $2,868, respectively, of compensation expense related to the 2009 Plan. At December 31, 2023, 657,860 of our common shares remained available for issuance under the 2009 Plan. Share Purchases During the years ended December 31, 2023, 2022 and 2021, w e purchased 48,329, 30,821 and 37,801 of o ur common shares, respectively, valued at weighted average sh are prices of $6.08, $17.54 and $26.55 per c ommon share, respectively, from certain of our current and former Trustees and officers and certain current and former officers and employees of RMR in satisfaction of tax withholding and payment obligations in connection with the vesting of awards of our common shares. Distributions During the years ended December 31, 2023, 2022 and 2021, we paid distributions on our common shares as follows: Annual Per Share Distribution Total Distributions Characterization of Distributions Year Return of Capital Ordinary Income Qualified Dividend 2023 $ 1.30 $ 63,187 100.00% —% —% 2022 $ 2.20 $ 106,630 62.68% 37.32% —% 2021 $ 2.20 $ 106,368 —% 100.00% —% On January 11, 2024, we declared a quarterly cash distribution payable to common shareholders of record on January 22, 2024 in the amount of $0.01 per share, or approximately $490. We expect to pay this distribution on or about February 15, 2024.

SCHEDULE III REAL ESTATE AND AC

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION	12 Months Ended
	Dec. 31, 2023
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION	Initial Cost to Company Costs Capitalized Subsequent to Acquisition Cost amount carried at Close of Period Property Location Number of Properties Encumbrances (1) Land Buildings Impairments/ Land Buildings Total (2) Accumulated (3) Date(s) Original 445 Jan Davis Drive Huntsville, AL 1 $ — $ 1,501 $ 1,492 $ — $ — $ 1,501 $ 1,492 $ 2,993 $ (199) 12/31/2018 2007 131 Clayton Street Montgomery, AL 1 — 920 9,084 417 — 920 9,501 10,421 (2,957) 6/22/2011 2007 4344 Carmichael Road Montgomery, AL 1 — 1,374 11,658 571 — 1,374 12,229 13,603 (3,109) 12/17/2013 2009 15451 North 28th Avenue Phoenix, AZ 1 — 1,917 7,416 1,239 — 1,917 8,655 10,572 (2,016) 9/10/2014 1996 711 S 14th Avenue Safford, AZ 1 — 460 11,708 903 (4,440) 364 8,267 8,631 (1,703) 6/16/2010 1992 Regents Center Tempe, AZ 2 — 4,121 3,042 354 — 4,121 3,396 7,517 (841) 12/31/2018 1988 Campbell Place Carlsbad, CA 2 — 5,769 3,871 7,595 — 5,769 11,466 17,235 (3,407) 12/31/2018 2007 Folsom Corporate Center (5) Folsom, CA 1 — 2,904 5,583 1,587 — 2,904 7,170 10,074 (1,238) 12/31/2018 2008 Bayside Technology Park Fremont, CA 1 — 10,784 648 255 — 10,784 903 11,687 (154) 12/31/2018 1990 10949 N. Mather Boulevard Rancho Cordova, CA 1 — 562 16,923 1,052 — 562 17,975 18,537 (4,675) 10/30/2013 2012 11020 Sun Center Drive Rancho Cordova, CA 1 — 1,466 8,797 1,543 — 1,466 10,340 11,806 (2,174) 12/20/2016 1983 100 Redwood Shores Parkway Redwood City, CA 1 — 14,454 7,721 — — 14,454 7,721 22,175 (1,071) 12/31/2018 1993 3875 Atherton Road Rocklin, CA 1 — 177 853 479 — 177 1,332 1,509 (140) 12/31/2018 1991 801 K Street Sacramento, CA 1 — 4,688 61,994 10,472 — 4,688 72,466 77,154 (15,524) 1/29/2016 1989 9815 Goethe Road Sacramento, CA 1 — 1,450 9,465 2,181 — 1,450 11,646 13,096 (3,400) 9/14/2011 1992 Capitol Place Sacramento, CA 1 — 2,290 35,891 8,674 — 2,290 44,565 46,855 (15,686) 12/17/2009 1988 4560 Viewridge Road (5) San Diego, CA 1 — 4,269 18,316 5,294 — 4,347 23,532 27,879 (14,798) 3/31/1997 1996 2115 O’Nel Drive San Jose, CA 1 — 12,305 5,062 385 — 12,305 5,447 17,752 (765) 12/31/2018 1984 North First Street San Jose, CA 1 — 8,311 4,003 443 — 8,311 4,446 12,757 (729) 12/31/2018 1984 Rio Robles Drive San Jose, CA 3 8,064 23,687 13,698 17,061 — 23,687 30,759 54,446 (3,779) 12/31/2018 1984 2500 Walsh Avenue Santa Clara, CA 1 — 6,687 8,326 280 — 6,687 8,606 15,293 (1,181) 12/31/2018 1982 3250 and 3260 Jay Street Santa Clara, CA 2 — 19,899 14,051 114 — 19,899 14,165 34,064 (1,949) 12/31/2018 1982 603 San Juan Avenue Stockton, CA 1 — 563 5,470 206 — 563 5,676 6,239 (1,586) 7/20/2012 2012 350 West Java Drive Sunnyvale, CA 1 — 24,609 462 978 — 24,609 1,440 26,049 (148) 12/31/2018 1984 7958 South Chester Street Centennial, CO 1 — 6,682 7,153 1,801 — 6,682 8,954 15,636 (1,265) 12/31/2018 2000 350 Spectrum Loop Colorado Springs, CO 1 — 3,650 7,732 594 — 3,650 8,326 11,976 (1,205) 12/31/2018 2000 12795 West Alameda Parkway Lakewood, CO 1 — 2,640 23,777 1,508 — 2,640 25,285 27,925 (8,849) 1/15/2010 1988 Corporate Center Lakewood, CO 3 — 2,887 27,537 2,613 — 2,887 30,150 33,037 (15,398) 10/11/2002 1980 11 Dupont Circle, NW Washington, DC 1 — 28,255 44,743 19,249 — 28,255 63,992 92,247 (12,479) 10/2/2017 1974 Initial Cost to Company Costs Capitalized Subsequent to Acquisition Cost amount carried at Close of Period Property Location Number of Properties Encumbrances (1) Land Buildings Impairments/ Land Buildings Total (2) Accumulated (3) Date(s) Original 1211 Connecticut Avenue, NW Washington, DC 1 — 30,388 24,667 4,855 — 30,388 29,522 59,910 (5,821) 10/2/2017 1967 1401 K Street, NW Washington, DC 1 — 29,215 34,656 8,485 — 29,215 43,141 72,356 (9,458) 10/2/2017 1929 20 Massachusetts Avenue Washington, DC 1 — 12,009 51,527 221,203 — 12,231 272,508 284,739 (48,475) 3/31/1997 1996 440 First Street, NW (5) Washington, DC 1 — 27,903 38,624 2,169 — 27,903 40,793 68,696 (6,341) 10/2/2017 1982 625 Indiana Avenue Washington, DC 1 — 26,000 25,955 12,158 — 26,000 38,113 64,113 (12,464) 8/17/2010 1989 840 First Street, NE Washington, DC 1 — 42,727 73,278 2,912 — 42,727 76,190 118,917 (12,414) 10/2/2017 2003 10350 NW 112th Avenue Miami, FL 1 — 4,798 2,757 2,354 — 4,798 5,111 9,909 (684) 12/31/2018 2002 7850 Southwest 6th Court Plantation, FL 1 — 4,800 30,592 14,993 — 4,800 45,585 50,385 (9,839) 5/12/2011 1999 8900 Grand Oak Circle Tampa, FL 1 — 1,100 11,773 1,661 — 1,100 13,434 14,534 (4,219) 10/15/2010 1994 180 Ted Turner Drive SW (5) Atlanta, GA 1 — 5,717 20,017 1,390 — 5,717 21,407 27,124 (5,989) 7/25/2012 2007 1224 Hammond Drive Atlanta, GA 1 — 13,040 135,459 11,583 — 13,040 147,042 160,082 (10,789) 6/25/2021 2020 Corporate Square Atlanta, GA 5 — 3,996 29,763 26,570 — 3,996 56,333 60,329 (21,009) 7/16/2004 1967 Executive Park Atlanta, GA 1 — 1,521 11,826 4,123 — 1,521 15,949 17,470 (9,089) 7/16/2004 1972 One Georgia Center (5) Atlanta, GA 1 — 10,250 27,933 20,903 — 10,250 48,836 59,086 (13,865) 9/30/2011 1968 One Primerica Parkway (4) Duluth, GA 1 25,904 6,927 22,951 40 — 6,927 22,991 29,918 (3,181) 12/31/2018 2013 4712 Southpark Boulevard Ellenwood, GA 1 — 1,390 19,635 911 — 1,390 20,546 21,936 (5,707) 7/25/2012 2005 8305 NW 62nd Avenue Johnston, IA 1 — 2,649 7,997 — — 2,649 7,997 10,646 (1,108) 12/31/2018 2011 1185, 1249 & 1387 S. Vinnell Way Boise, ID 3 — 3,390 29,026 1,246 — 3,390 30,272 33,662 (8,663) 9/11/2012 1996; 1997; 2002 2020 S. Arlington Heights (5) Arlington Heights, IL 1 — 1,450 13,588 2,129 — 1,450 15,717 17,167 (5,138) 12/29/2009 1988 1000 W. Fulton (5) Chicago, IL 1 — 42,935 252,914 528 — 42,935 253,442 296,377 (21,274) 6/24/2021 2015 HUB 1415 Naperville, IL 1 — 12,333 20,586 23,564 — 12,333 44,150 56,483 (7,248) 12/31/2018 2001 7601 and 7635 Interactive Way Indianapolis, IN 2 — 3,337 14,522 34 — 3,337 14,556 17,893 (1,900) 12/31/2018 2003 Intech Park Indianapolis, IN 3 — 4,170 69,759 12,052 — 4,170 81,811 85,981 (26,133) 10/14/2011 2000; 2001; 2008 7125 Industrial Road Florence, KY 1 — 1,698 11,722 293 — 1,698 12,015 13,713 (3,349) 12/31/2012 1980 251 Causeway Street Boston, MA 3 — 26,851 36,756 5,296 — 26,851 42,052 68,903 (9,174) 8/17/2010 1987 330 Billerica Road Chelmsford, MA 1 — 2,477 — 10,246 — 2,477 10,246 12,723 (1,924) 12/31/2018 1984 75 Pleasant Street Malden, MA 1 — 1,050 31,086 275 — 1,050 31,361 32,411 (10,636) 5/24/2010 2008 25 Newport Avenue Quincy, MA 1 — 2,700 9,199 3,106 — 2,700 12,305 15,005 (3,572) 2/16/2011 1985 Initial Cost to Company Costs Capitalized Subsequent to Acquisition Cost amount carried at Close of Period Property Location Number of Properties Encumbrances (1) Land Buildings Impairments/ Land Buildings Total (2) Accumulated (3) Date(s) Original 314 Littleton Road Westford, MA 1 — 5,691 8,487 100 — 5,691 8,587 14,278 (1,201) 12/31/2018 2007 Annapolis Commerce Center Annapolis, MD 2 — 4,057 7,665 4,806 — 4,057 12,471 16,528 (2,241) 10/2/2017 1989 4201 Patterson Avenue Baltimore, MD 1 — 901 8,097 4,134 (85) 893 12,154 13,047 (7,198) 10/15/1998 1989 7001 Columbia Gateway Drive Columbia, MD 1 — 5,642 10,352 3,444 — 5,642 13,796 19,438 (1,605) 12/31/2018 2008 Hillside Center Columbia, MD 2 — 3,437 4,228 1,015 — 3,437 5,243 8,680 (1,098) 10/2/2017 2001 TenThreeTwenty Columbia, MD 1 — 3,126 16,361 4,011 — 3,126 20,372 23,498 (3,418) 10/2/2017 1982 3300 75th Avenue Landover, MD 1 29,537 4,110 36,371 3,730 — 4,110 40,101 44,211 (13,789) 2/26/2010 1985 Redland 520/530 Rockville, MD 3 — 12,714 61,377 8,002 — 12,714 69,379 82,093 (11,313) 10/2/2017 2008 Redland 540 Rockville, MD 1 — 10,740 17,714 6,108 — 10,740 23,822 34,562 (5,344) 10/2/2017 2003 3550 Green Court Ann Arbor, MI 1 — 3,630 4,857 — — 3,630 4,857 8,487 (714) 12/31/2018 1998 11411 E. Jefferson Avenue Detroit, MI 1 — 630 18,002 586 — 630 18,588 19,218 (6,322) 4/23/2010 2009 Rosedale Corporate Plaza Roseville, MN 1 — 672 6,045 819 — 672 6,864 7,536 (3,917) 12/1/1999 1987 1300 Summit Street Kansas City, MO 1 — 2,776 12,070 925 — 2,776 12,995 15,771 (3,690) 9/27/2012 1998 2555 Grand Boulevard (5) Kansas City, MO 1 — 4,209 51,522 5,414 — 4,209 56,936 61,145 (8,213) 12/31/2018 2003 4241 NE 34th Street Kansas City, MO 1 — 1,133 5,649 5,056 — 1,470 10,368 11,838 (5,455) 3/31/1997 1995 1220 Echelon Parkway Jackson, MS 1 14,510 440 25,458 1,571 — 440 27,029 27,469 (7,500) 7/25/2012 2009 2300 and 2400 Yorkmont Road (5) Charlotte, NC 2 — 1,334 19,075 4,222 — 1,334 23,297 24,631 (3,549) 12/31/2018 1995 18010 and 18020 Burt Street Omaha, NE 2 — 6,977 12,500 2,369 — 6,977 14,869 21,846 (1,733) 12/31/2018 2012 500 Charles Ewing Boulevard Ewing, NJ 1 42,279 4,808 26,002 1,554 — 4,808 27,556 32,364 (3,737) 12/31/2018 2012 299 Jefferson Road Parsippany, NJ 1 — 4,543 2,914 1,282 — 4,543 4,196 8,739 (723) 12/31/2018 2011 One Jefferson Road Parsippany, NJ 1 — 4,415 5,249 103 — 4,415 5,352 9,767 (741) 12/31/2018 2009 Airline Corporate Center Colonie, NY 1 — 790 6,400 1,876 — 790 8,276 9,066 (2,239) 6/22/2012 2004 1212 Pittsford - Victor Road Pittsford, NY 1 — 608 78 1,627 — 608 1,705 2,313 (174) 12/31/2018 1965 2231 Schrock Road Columbus, OH 1 — 716 217 578 — 716 795 1,511 (163) 12/31/2018 1999 8800 Tinicum Boulevard Philadelphia, PA 1 — 5,573 22,686 6,022 — 5,573 28,708 34,281 (3,658) 12/31/2018 2000 446 Wrenplace Road Fort Mill, SC 1 — 5,031 22,524 43 — 5,031 22,567 27,598 (1,704) 12/22/2020 2019 9680 Old Bailes Road Fort Mill, SC 1 — 834 2,944 91 — 834 3,035 3,869 (423) 12/31/2018 2007 16001 North Dallas Parkway Addison, TX 2 — 10,282 63,071 2,558 — 10,282 65,629 75,911 (9,485) 12/31/2018 1987 Initial Cost to Company Costs Capitalized Subsequent to Acquisition Cost amount carried at Close of Period Property Location Number of Properties Encumbrances (1) Land Buildings Impairments/ Land Buildings Total (2) Accumulated (3) Date(s) Original Research Park Austin, TX 2 — 4,258 13,747 534 — 4,258 14,281 18,539 (3,403) 12/31/2018 1999 10451 Clay Road Houston, TX 1 — 5,495 10,253 2,432 — 5,495 12,685 18,180 (1,809) 12/31/2018 2013 202 North Castlegory Road Houston, TX 1 — 863 5,024 41 — 863 5,065 5,928 (657) 12/31/2018 2016 4221 W. John Carpenter Freeway Irving, TX 1 — 1,413 2,365 1,843 — 1,413 4,208 5,621 (1,445) 12/31/2018 1995 8675,8701-8711 Freeport Pkwy and 8901 Esters Boulevard Irving, TX 3 — 12,970 31,566 138 — 12,970 31,704 44,674 (4,375) 12/31/2018 1990 1511 East Common Street New Braunfels, TX 1 — 4,965 1,266 251 — 4,965 1,517 6,482 (323) 12/31/2018 2005 2900 West Plano Parkway Plano, TX 1 — 6,819 8,831 — — 6,819 8,831 15,650 (1,224) 12/31/2018 1998 3400 West Plano Parkway Plano, TX 1 — 4,543 15,964 321 — 4,543 16,285 20,828 (2,286) 12/31/2018 1994 3600 Wiseman Boulevard San Antonio, TX 1 — 3,493 6,662 2,134 — 3,493 8,796 12,289 (1,059) 12/31/2018 2004 701 Clay Road (4) Waco, TX 1 25,903 2,030 8,708 14,651 — 2,060 23,329 25,389 (9,787) 12/23/1997 1997 1800 Novell Place Provo, UT 1 — 7,487 43,487 13,364 — 7,487 56,851 64,338 (7,307) 12/31/2018 2000 4885-4931 North 300 West Provo, UT 2 — 3,915 9,429 21 — 3,915 9,450 13,365 (1,392) 12/31/2018 2009 14660, 14672 & 14668 Lee Road (5) Chantilly, VA 3 — 6,966 74,214 17,518 — 6,966 91,732 98,698 (15,123) 12/22/2016 1998; 2002; 2006 Enterchange at Meadowville Chester, VA 1 — 1,478 9,594 1,369 — 1,478 10,963 12,441 (2,720) 8/28/2013 1999 7987 Ashton Avenue Manassas, VA 1 — 1,562 8,253 1,069 — 1,562 9,322 10,884 (1,946) 1/3/2017 1989 Two Commercial Place Norfolk, VA 1 — 4,494 21,508 1,033 — 4,494 22,541 27,035 (2,976) 12/31/2018 1974 1759 Business Center Drive Reston, VA 1 — 4,033 28,517 2,517 — 4,033 31,034 35,067 (7,563) 5/28/2014 1987 1760 Business Center Drive Reston, VA 1 — 5,033 50,141 6,320 — 5,033 56,461 61,494 (13,571) 5/28/2014 1987 1775 Wiehle Avenue Reston, VA 1 — 4,138 26,120 5,716 — 4,138 31,836 35,974 (5,376) 10/2/2017 2001 9201 Forest Hill Avenue Richmond, VA 1 — 1,344 375 668 — 1,344 1,043 2,387 (239) 12/31/2018 1985 9960 Mayland Drive Richmond, VA 1 — 2,614 15,930 4,690 — 2,614 20,620 23,234 (5,109) 5/20/2014 1994 1751 Blue Hills Drive (5) Roanoke, VA 1 — 2,689 7,761 — — 2,689 7,761 10,450 (1,076) 12/31/2018 2003 Atlantic Corporate Park Sterling, VA 2 — 5,752 29,316 3,616 — 5,752 32,932 38,684 (5,532) 10/2/2017 2008 Orbital Sciences Campus (5) Sterling, VA 3 — 12,275 19,320 7,400 — 12,269 26,726 38,995 (3,205) 12/31/2018 2001 Sterling Park Business Center Sterling, VA 1 25,934 5,871 44,324 127 — 5,871 44,451 50,322 (6,951) 10/2/2017 2016 65 Bowdoin Street S. Burlington, VT 1 — 700 8,416 148 — 700 8,564 9,264 (2,959) 4/9/2010 2009 Stevens Center (5) Richland, WA 2 — 3,970 17,035 4,776 — 4,042 21,739 25,781 (13,025) 3/31/1997 1995 Unison Elliott Bay-Lab Space Seattle, WA 2 — 17,316 34,281 137,343 — 17,316 171,624 188,940 (5,302) 12/31/2018 2000 Unison Elliott Bay-Office Space Seattle, WA 1 — 9,324 18,459 5,101 — 9,324 23,560 32,884 (2,953) 12/31/2018 2000 Initial Cost to Company Costs Capitalized Subsequent to Acquisition Cost amount carried at Close of Period Property Location Number of Properties Encumbrances (1) Land Buildings Impairments/ Land Buildings Total (2) Accumulated (3) Date(s) Original 5353 Yellowstone Road (5) Cheyenne, WY 1 — 1,915 8,217 2,402 — 1,950 10,584 12,534 (6,251) 3/31/1997 1995 151 $ 172,131 $ 785,646 $ 2,492,042 $ 792,516 $ (4,525) $ 786,310 $ 3,279,369 $ 4,065,679 $ (650,179) Properties Held for Sale 400 South Jefferson Street Chicago, IL 1 — 19,379 20,115 1,136 (11,299) 13,555 15,776 29,331 (3,030) 12/31/2018 1947 1 — 19,379 20,115 1,136 (11,299) 13,555 15,776 29,331 (3,030) 152 $ 172,131 $ 805,025 $ 2,512,157 $ 793,652 $ (15,824) $ 799,865 $ 3,295,145 $ 4,095,010 $ (653,209) (1) Represents mortgage debt, net of the unamortized balance of debt issuance costs totaling $5,189. (2) Excludes the value of real estate intangibles. Aggregate cost for federal income tax purposes is approximately $7,540,917. (3) Depreciation on building and improvements is provided for periods ranging up to 40 years and on equipment up to seven years. (4) These two properties are collateral for our $54,300 mortgage note. (5) These 19 properties (with the exception of 14660 Lee Road) are collateral for our $325,000 secured revolving credit facility and $100,000 term loan under our amended and restated credit facility, which we entered into in January 2024. An analysis of the carrying amount of real estate properties and accumulated depreciation is as follows: Real Estate Properties Accumulated Depreciation Balance at December 31, 2020 $ 3,522,143 $ 451,914 Additions 584,805 92,266 Loss on asset impairment (58,696) — Disposals (72,137) (8,675) Cost basis adjustment (1) (37,239) (37,239) Reclassification of assets of properties held for sale (27,790) (2,354) Balance at December 31, 2021 3,911,086 495,912 Additions 222,951 96,966 Loss on asset impairment (17,303) — Disposals (173,841) (26,997) Cost basis adjustment (1) (4,235) (4,235) Reclassification of assets of properties held for sale (2,584) (188) Balance at December 31, 2022 3,936,074 561,458 Additions 221,246 107,460 Loss on asset impairment (11,299) — Disposals (51,011) (15,709) Reclassification of assets of properties held for sale (29,331) (3,030) Balance at December 31, 2023 $ 4,065,679 $ 650,179 (1) Represents the reclassification between accumulated depreciation and building made to certain properties reclassified as assets of properties held for sale at fair value less costs to sell in accordance with GAAP.

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Pay vs Performance Disclosure
Net Income (Loss)	$ (69,432)	$ (6,109)	$ (8,180)

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation. These consolidated financial statements include the accounts of us and our subsidiaries, all of which are wholly owned directly or indirectly by us. All intercompany transactions and balances with or among our consolidated subsidiaries have been eliminated.
Real Estate Properties	Real Estate Properties. We record our properties at cost and provide depreciation on real estate investments on a straight line basis over estimated useful lives generally ranging from 7 to 40 years. In some circumstances, we engage independent real estate appraisal firms to provide market information and evaluations which are relevant to our purchase price allocations and determinations of useful lives; however, we are ultimately responsible for the purchase price allocations and determinations of useful lives. We allocate the purchase prices of our properties to land, buildings and improvements based on determinations of the relative fair values of these assets assuming the properties are vacant. We determine the fair value of each property using methods similar to those used by independent appraisers, which may involve estimated cash flows that are based on a number of factors, including capitalization rates and discount rates, among others. We allocate a portion of the purchase price of our properties to above market and below market leases based on the present value (using an interest rate which reflects the risks associated with acquired in place leases at the time each property was acquired by us) of the difference, if any, between (i) the contractual amounts to be paid pursuant to the acquired in place leases and (ii) our estimates of fair market lease rates for the corresponding leases, measured over a period equal to the terms of the respective leases. We allocate a portion of the purchase price to acquired in place leases and tenant relationships based upon market estimates to lease up the property based on the leases in place at the time of purchase. We allocate this aggregate value between acquired in place lease values and tenant relationships based on our evaluation of the specific characteristics of each tenant’s lease. However, we have not separated the value of tenant relationships from the value of acquired in place leases because such value and related amortization expense is immaterial to the accompanying consolidated financial statements. In making these allocations, we consider factors such as estimated carrying costs during the expected lease up periods, including real estate taxes, insurance and other operating income and expenses and costs, such as leasing commissions, legal and other related expenses, to execute similar leases in current market conditions at the time a property was acquired by us. If the value of tenant relationships becomes material in the future, we may separately allocate those amounts and amortize the allocated amounts over the estimated life of the relationships. For transactions that qualify as business combinations, we allocate the excess, if any, of the consideration over the fair value of the assets acquired to goodwill. We amortize capitalized above market lease values (included in acquired real estate leases, net in our consolidated balance sheets) and below market lease values (presented as assumed real estate lease obligations, net in our consolidated balance sheets) as a reduction or increase, respectively, to rental income over the terms of the associated leases. Such amortization resulted in a net increase to rental income of $252 during the year ended December 31, 2023 and net decreases to rental income of $975 and $2,288 during the years ended December 31, 2022 and 2021, respectively. We amortize the value of acquired in place leases (included in acquired real estate leases, net in our consolidated balance sheets), exclusive of the value of above market and below market acquired in place leases, over the terms of the associated leases. Such amortization, which is included in depreciation and amortization expense, amounted to $93,057, $118,728 and $142,538 during the years ended December 31, 2023, 2022 and 2021, respectively. If a lease is terminated prior to its stated expiration, we write off the unamortized amounts relating to that lease. We regularly evaluate whether events or changes in circumstances have occurred that could indicate an impairment in the value of long lived assets. Impairment indicators may include declining tenant occupancy, lack of progress releasing vacant space, tenant bankruptcies, low long term prospects for improvement in property performance, weak or declining tenant profitability, cash flow or liquidity, our decision to dispose of an asset before the end of its estimated useful life and legislative, market or industry changes that could permanently reduce the value of a property. 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 consideration of impairment upon the events or changes in circumstances described above, we regularly evaluate the remaining useful lives of our long lived assets. If we change our estimate of the remaining useful lives, we allocate the carrying value of the affected assets over their revised remaining useful lives.
Cash and Cash Equivalents	Cash and Cash Equivalents. We consider highly liquid investments with original maturities of three months or less at the date of purchase to be cash equivalents.
Restricted Cash	Restricted Cash. 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.
Deferred Leasing Costs	Deferred Leasing Costs
Debt Issuance Costs	Debt Issuance Costs
Equity Method Investments	Equity Method Investments. As of December 31, 2023, we had noncontrolling ownership interests of 51% and 50% in two unconsolidated joint ventures that owned three properties. The properties owned by these joint ventures are encumbered by an aggregate of $82,000 of mortgage indebtedness. We did not control the activities that are most significant to these joint ventures and, as a result, we accounted for our investments in these joint ventures under the equity method of accounting. See Note 4 for more information regarding our unconsolidated joint ventures. We periodically evaluate our equity method investments 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 and the extent to which the market value of our investment is below our carrying value, the financial condition of our investees, 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 record an impairment charge to adjust the basis of the investment to its estimated fair value.
Revenue Recognition	Revenue Recognition. We are a lessor of commercial office properties. Our leases provide our tenants with the contractual right to use and economically benefit from all of the physical space specified in the leases; therefore, we have determined to evaluate our leases as lease arrangements. 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. Allowances for bad debts are recognized as a direct reduction of rental income. Certain of our leases contain non-lease components, such as property level operating expenses and capital expenditures reimbursed by our tenants as well as other required lease payments. We have made the policy election to not separate the lease and non-lease components because (i) the lease components are operating leases and (ii) the timing and pattern of recognition of the non-lease components are the same as those of the lease components. We apply Accounting Standards Codification 842, Leases , to the combined component. Income derived by our leases is recorded in rental income in our consolidated statements of comprehensive income (loss). Certain tenants are obligated to pay directly their obligations under their leases for insurance, real estate taxes and certain other expenses. These obligations, which have been assumed by the tenants under the terms of their respective leases, are not reflected in our consolidated financial statements. To the extent any tenant responsible for any such obligations under the applicable lease defaults on such lease or if it is deemed probable that the tenant will fail to pay for such obligations, we would record a liability for such obligations. See Note 5 for more information regarding our leases.
Income Taxes	Income Taxes.
Per Common Share Amounts	Per Common Share Amounts. We calculate basic earnings per common share using the two class method. 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.
Use of Estimates	Use of Estimates. Preparation of these financial statements in conformity with GAAP requires us to make estimates and assumptions that may affect the amounts reported in these consolidated financial statements and related notes. The actual results could differ from these estimates. Significant estimates in the consolidated financial statements include purchase price allocations, useful lives of fixed assets and assessment of impairment of real estate and the related intangibles.
Segment Reporting	Segment Reporting. We operate in one business segment: direct ownership of real estate properties.
New Accounting Pronouncements	New Accounting Pronouncements. O n November 27, 2023, the Financial Accounting Standards Board issued Accounting Standards Update No. 2023-07, Segment Reporting (Topic 280): Improvements to Reportable Segment Disclosures, or ASU No. 2023-07, which requires public entities to: (i) provide disclosures of significant segment expenses and other segment items if they are regularly provided to the Chief Operating Decision Maker, or the CODM, and included in each reported measure of segment profit or loss; (ii) provide all annual disclosures about a reportable segment’s profit or loss and assets currently required by Accounting Standards Codification 280, Segment Reporting, or ASC 280, in interim periods; and (iii) disclose the CODM’s title and position, as well as an explanation of how the CODM uses the reported measures and other disclosures. Public entities with a single reportable segment must apply all the disclosure requirements of ASU No. 2023-07, as well as all the existing segment disclosures under ASC 280. The amendments in ASU No. 2023-07 are incremental to the requirements in ASC 280 and do not change how a public entity identifies its operating segments, aggregates those operating segments, or applies the quantitative thresholds to determine its reportable segments. ASU No. 2023-07 should be applied retrospectively to all prior periods presented in the financial statements and is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024, with early adoption permitted. We are currently evaluating the impact ASU No. 2023-07 will have on our consolidated financial statements and disclosures.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2023
Accounting Policies [Abstract]
Schedule of Real Estate Properties	As of December 31, 2023 and 2022, our acquired real estate leases and assumed real estate lease obligations, excluding properties classified as held for sale, were as follows: December 31, 2023 2022 Acquired real estate leases: Capitalized above market lease values $ 14,758 $ 15,792 Less: accumulated amortization (10,876) (9,672) Capitalized above market lease values, net 3,882 6,120 Lease origination value 572,766 728,773 Less: accumulated amortization (313,150) (365,560) Lease origination value, net 259,616 363,213 Acquired real estate leases, net $ 263,498 $ 369,333 Assumed real estate lease obligations: Capitalized below market lease values $ 25,678 $ 27,033 Less: accumulated amortization (14,013) (12,876) Assumed real estate lease obligations, net $ 11,665 $ 14,157

Per Common Share Amounts (Table

Per Common Share Amounts (Tables)	12 Months Ended
	Dec. 31, 2023
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The calculation of basic and diluted earnings per share is as follows (amounts in thousands, except per share amounts): Year Ended December 31, 2023 2022 2021 Numerators: Net loss $ (69,432) $ (6,109) $ (8,180) Income attributable to unvested participating securities (305) (427) — Net loss used in calculating earnings per share $ (69,737) $ (6,536) $ (8,180) Denominators: Weighted average common shares outstanding - basic and diluted (1) 48,389 48,278 48,195 Net loss per common share - basic and diluted $ (1.44) $ (0.14) $ (0.17) (1) For the years ended December 31, 2023, 2022 and 2021, there were no dilutive common shares. For the year ended December 31, 2021, 34 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 (Tables)

Real Estate Properties (Tables)	12 Months Ended
	Dec. 31, 2023
Real Estate [Abstract]
Schedule of Business Acquisitions, by Acquisition	We allocated the purchase prices of these acquisitions based on the relative estimated fair values of the acquired assets and assumed liabilities as follows: Acquisition Date Location Number of Properties Rentable Square Feet Purchase Price Land Buildings and Improvements Acquired Real Estate Leases Assumed Real Estate Lease Obligations June 2021 Chicago, IL (1) 1 531,000 $ 368,331 $ 42,935 $ 258,348 $ 76,136 $ (9,088) June 2021 Atlanta, GA 1 346,000 180,602 13,040 135,459 32,103 — August 2021 Boston, MA 1 49,000 27,545 16,103 10,217 1,225 — 3 926,000 $ 576,478 $ 72,078 $ 404,024 $ 109,464 $ (9,088) (1) Purchase price includes an adjustment of $13,031 t o record an estimated real estate tax liability as of the acquisition date.
Schedule of Disposal Groups	Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate January 2023 3 Richmond, VA (2) 89,000 $ 5,350 $ 2,548 April 2023 1 Phoenix, AZ 107,000 4,900 511 June 2023 1 Vernon Hills, IL 100,000 2,825 (2,816) September 2023 1 Windsor Mill, MD 80,000 10,500 244 October 2023 1 Santa Clara, CA 66,000 16,049 705 November 2023 1 Chelmsford, MA 111,000 5,250 2,588 8 553,000 $ 44,874 $ 3,780 (1) Gross sales price is the gross contract price, excluding closing costs. (2) Properties were classified as held for sale as of December 31, 2022. Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate Loss on Impairment of Real Estate January 2022 1 Rockville, MD (2) 129,000 $ 6,750 $ (72) $ — February 2022 2 Chesapeake, VA (2) 172,000 18,945 2,296 — March 2022 1 Milwaukee, WI (2) 29,000 3,775 (75) — May 2022 1 Holtsville, NY 264,000 28,500 1,900 — June 2022 1 Fairfax, VA 184,000 19,750 (13,537) — July 2022 1 Houston, TX 206,000 9,800 (135) 15,278 August 2022 3 Birmingham, AL 448,000 16,050 (265) 3,709 August 2022 1 Erlanger, KY 86,000 2,600 135 2,184 September 2022 2 Chesapeake, VA 214,000 24,000 62 649 September 2022 2 Everett, WA 112,000 31,500 11,959 — September 2022 1 Salem, OR 233,000 34,250 5,369 — November 2022 1 Kapolei, HI (3) 109,000 4,000 2,504 — November 2022 1 Englewood, CO 140,000 11,100 860 — 18 2,326,000 $ 211,020 $ 11,001 $ 21,820 (1) Gross sales price is the gross contract price, excluding closing costs. (2) Properties were classified as held for sale as of December 31, 2021. (3) Property is a leasable land parcel. Date of Sale Number of Properties Location Rentable Square Feet Gross Sales Price (1) Gain (Loss) on Sale of Real Estate Loss on Impairment of Real Estate January 2021 — Kansas City, MO (2)(3) 10,000 $ 845 $ (63) $ — January 2021 1 Richmond, VA (2) 311,000 130,000 54,181 — April 2021 1 Huntsville, AL 1,371,000 39,000 — 5,383 July 2021 1 Fresno, CA 532,000 6,000 — 33,902 July 2021 1 Liverpool, NY 38,000 650 31 — August 2021 1 Memphis, TN 205,000 15,270 287 — September 2021 1 Stoneham, MA 98,000 6,650 (282) 5,911 October 2021 — Sterling, VA (4) — 28,500 24,200 — 6 2,565,000 $ 226,915 $ 78,354 $ 45,196 (1) Gross sales price is the gross contract price, excluding closing costs. (2) Properties were classified as held for sale as of December 31, 2020. (3) Consists of a warehouse facility. (4)
Schedule of Joint Ventures	As of December 31, 2023 and 2022, our investments in unconsolidated joint ventures consisted of the following: OPI Ownership OPI Carrying Value of Investments at December 31, Number of Properties Location Rentable Square Feet Joint Venture 2023 2022 Prosperity Metro Plaza 51% $ 18,128 $ 19,237 2 Fairfax, VA 346,000 1750 H Street, NW 50% — 15,892 1 Washington, D.C. 122,000 Total $ 18,128 $ 35,129 3 468,000 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 December 31, 2023 and 2022 (2) Prosperity Metro Plaza 4.09% 12/1/2029 $ 50,000 1750 H Street, NW (3) 3.69% 8/1/2027 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 did not own. None of the debt is recourse to us. (3)

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2023
Leases [Abstract]
Schedule of Future Contractual Lease Payments to be Received	The following operating lease maturity analysis presents the future contractual lease payments to be received by us through 2053 as of December 31, 2023: Year Amount 2024 $ 378,748 2025 339,500 2026 310,205 2027 281,109 2028 243,928 Thereafter 1,428,379 Total $ 2,981,869

Indebtedness (Tables)

Indebtedness (Tables)	12 Months Ended
	Dec. 31, 2023
Debt Disclosure [Abstract]
Schedule of Long-Term Debt Instruments	As of December 31, 2023 and 2022, our outstanding indebtedness consisted of the following: December 31, 2023 2022 Revolving credit facility, due in 2024 $ 205,000 $ 195,000 Mortgage note payable, 3.700% interest rate, due in 2023 (1) — 50,000 Senior unsecured notes, 4.250% interest rate, due in 2024 350,000 350,000 Senior unsecured notes, 4.500% interest rate, due in 2025 650,000 650,000 Senior unsecured notes, 2.650% interest rate, due in 2026 300,000 300,000 Senior unsecured notes, 2.400% interest rate, due in 2027 350,000 350,000 Mortgage note payable, 8.272% interest rate, due in 2028 42,700 — Mortgage note payable, 8.139% interest rate, due in 2028 26,340 — Mortgage note payable, 7.671% interest rate, due in 2028 54,300 — Senior unsecured notes, 3.450% interest rate, due in 2031 400,000 400,000 Mortgage note payable, 7.210% interest rate, due in 2033 30,680 — Mortgage note payable, 7.305% interest rate, due in 2033 8,400 — Mortgage note payable, 7.717% interest rate, due in 2033 14,900 — Senior unsecured notes, 6.375% interest rate, due in 2050 162,000 162,000 2,594,320 2,457,000 Unamortized debt premiums, discounts and issuance costs (21,711) (24,208) $ 2,572,609 $ 2,432,792 (1) This mortgage note was repaid at maturity in June 2023. During the year ended December 31, 2023, we issued six fixed rate, interest-only mortgage notes as summarized in the following table: Issuance Date Secured By Principal Balance (1) Interest Rate Maturity Net Book Value of Collateral as of December 31, 2023 May 2023 (2) One property $ 30,680 7.210% 7/1/2033 $ 36,807 June 2023 One property 26,340 8.139% 7/1/2028 52,342 June 2023 One property 42,700 8.272% 7/1/2028 42,834 June 2023 One property 8,400 7.305% 7/1/2033 19,035 August 2023 One property 14,900 7.717% 9/1/2033 23,908 September 2023 Two properties 54,300 7.671% 10/6/2028 64,828 Total / Weighted Average $ 177,320 7.792% $ 239,754 (1) Our mortgage notes are non-recourse, subject to certain limited exceptions and do not contain any material financial covenants. (2) Requires interest-only payments through May 2028, at which time principal and interest payments are due monthly through the maturity date.
Schedule of Required Principal Payments	The required principal payments due during the next five years and thereafter under all our outstanding consolidated debt as of December 31, 2023 were as follows: Year Principal Payment 2024 $ 555,000 2025 650,000 2026 300,000 2027 350,000 2028 123,487 Thereafter 615,833 Total $ 2,594,320 (1) (1) Total consolidated debt outstanding as of December 31, 2023, net of unamortized premiums, discounts and issuance costs totaling $21,711, was $2,572,609.

Fair Value of Assets and Liab_2

Fair Value of Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2023
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value	The following table presents certain of our assets measured at fair value at December 31, 2023, categorized by 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) $ 39,000 $ — $ 39,000 $ — (1) We recorded an impairment charge of $11,299 to reduce the carrying value of one property in our consolidated balance sheet to its estimated fair value less estimated costs to sell of $1,777, based on a negotiated sales price with a third party buyer (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 December 31, 2023 and 2022, the fair values of our financial instruments approximated their carrying values in our consolidated financial statements, due to their short term nature or floating interest rates, except as follows: As of December 31, 2023 As of December 31, 2022 Financial Instrument Carrying Value (1) Fair Value Carrying Value (1) Fair Value Senior unsecured notes, 4.25% interest rate, due in 2024 $ 349,144 $ 331,510 $ 346,863 $ 331,601 Senior unsecured notes, 4.50% interest rate, due in 2025 646,266 510,445 642,818 589,388 Senior unsecured notes, 2.650% interest rate, due in 2026 298,464 185,934 297,839 232,770 Senior unsecured notes, 2.400% interest rate, due in 2027 348,086 196,147 347,466 256,606 Senior unsecured notes, 3.450% interest rate, due in 2031 396,614 199,060 396,178 268,004 Senior unsecured notes, 6.375% interest rate, due in 2050 156,904 83,916 156,711 113,075 Mortgage notes payable (2)(3) 172,131 179,813 49,917 49,099 Total $ 2,367,609 $ 1,686,825 $ 2,237,792 $ 1,840,543 (1) Includes unamortized debt premiums, discounts and issuance costs totaling $21,711 and $24,208 as of December 31, 2023 and 2022, respectively. (2) Balances as of December 31, 2022 include a mortgage note secured by one property with an outstanding principal balance of $50,000 that was repaid in June 2023. (3) Balances as of December 31, 2023 include six mortgage notes issued during the year ended December 31, 2023 with an aggregate principal balance of $177,320.

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	12 Months Ended
	Dec. 31, 2023
Equity [Abstract]
Summary of Shares Granted And Vested Under The Terms of The Entity's 2009 Plan	A summary of shares awarded, forfeited, vested and unvested under the terms of the 2009 Plan for the years ended December 31, 2023, 2022 and 2021, is as follows: 2023 2022 2021 Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Number of Shares Weighted Average Grant Date Fair Value Unvested at beginning of year 231,301 $ 21.47 182,224 $ 26.23 157,521 $ 29.26 Awarded 241,800 $ 6.04 172,700 $ 17.74 145,800 $ 26.28 Forfeited (3,700) $ 17.31 (1,900) $ 25.97 (700) $ 25.97 Vested (180,720) $ 16.00 (121,723) $ 23.24 (120,397) $ 30.24 Unvested at end of year 288,681 $ 12.01 231,301 $ 21.47 182,224 $ 26.23
Schedule of Dividends	During the years ended December 31, 2023, 2022 and 2021, we paid distributions on our common shares as follows: Annual Per Share Distribution Total Distributions Characterization of Distributions Year Return of Capital Ordinary Income Qualified Dividend 2023 $ 1.30 $ 63,187 100.00% —% —% 2022 $ 2.20 $ 106,630 62.68% 37.32% —% 2021 $ 2.20 $ 106,368 —% 100.00% —%

Organization (Details)

Organization (Details)	12 Months Ended
	Dec. 31, 2023 ft² joint_venture property	Dec. 31, 2021 ft²
Real Estate Properties [Line Items]
Number of properties (in properties) | property	152
Rentable area of properties (in square feet)		926,000
Number of joint ventures | joint_venture	2
Unconsolidated Joint Ventures
Real Estate Properties [Line Items]
Number of properties (in properties) | property	3
Rentable area of properties (in square feet)	468,000
Number of joint ventures | joint_venture	2
Joint Venture Property 1
Real Estate Properties [Line Items]
Percentage of ownership interest	51%
Joint Venture Property 2
Real Estate Properties [Line Items]
Percentage of ownership interest	50%
Continuing Operations
Real Estate Properties [Line Items]
Rentable area of properties (in square feet)	20,541,000

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Real Estate Properties, Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Real Estate [Line Items]
Net increase (decrease) to rental income	$ 252	$ (975)	$ (2,288)
Amortization of the value of leases	92,805	119,703	144,826
Projected future amortization of net intangible lease assets and liabilities, excluding those classified as discontinued operations
2024	67,692
2025	48,838
2026	35,068
2027	26,833
2028	14,123
Thereafter	59,279
Original Value Lease
Real Estate [Line Items]
Amortization of the value of leases	$ 93,057	$ 118,728	$ 142,538
Minimum | Buildings and Improvements
Real Estate [Line Items]
Property, plant and equipment, useful life	7 years
Maximum | Buildings and Improvements
Real Estate [Line Items]
Property, plant and equipment, useful life	40 years
Weighted Average
Real Estate [Line Items]
Below market, acquired lease amortization period	11 years
Weighted Average | Above Market Lease
Real Estate [Line Items]
Acquired lease amortization period	3 years 4 months 24 days
Weighted Average | Original Value Lease
Real Estate [Line Items]
Acquired lease amortization period	6 years 6 months

Summary of Significant Accoun_5

Summary of Significant Accounting Policies - Schedule of Real Estate Assets and Obligations (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Real Estate [Line Items]
Acquired real estate leases, net	$ 263,498	$ 369,333
Capitalized below market lease values	25,678	27,033
Less: accumulated amortization	(14,013)	(12,876)
Assumed real estate lease obligations, net	11,665	14,157
Above Market Lease
Real Estate [Line Items]
Real estate leases	14,758	15,792
Less: accumulated amortization	(10,876)	(9,672)
Acquired real estate leases, net	3,882	6,120
Original Value Lease
Real Estate [Line Items]
Real estate leases	572,766	728,773
Less: accumulated amortization	(313,150)	(365,560)
Acquired real estate leases, net	$ 259,616	$ 363,213

Summary of Significant Accoun_6

Summary of Significant Accounting Policies - Deferred Leasing and Debt Issuance Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Amortization of deferred leasing costs	$ 8,737	$ 6,869	$ 6,691
Deferred sales inducement cost, amortization expense	1,326	1,124	$ 1,187
Deferred leasing costs, gross	113,433	94,680
Accumulated amortization of deferred leasing costs	26,462	21,582
Future amortization of deferred leasing costs, excluding those classified as discontinued operations
2024	11,807
2025	10,549
2026	9,912
2027	8,919
2028	8,116
Thereafter	37,668
Deferred financing fees, net	16,623	13,589
Future amortization of deferred financing fees
2024	3,147
2025	2,573
2026	2,239
2027	1,499
2028	1,231
Thereafter	6,022
Line of Credit
Future amortization of deferred leasing costs, excluding those classified as discontinued operations
Maximum borrowing capacity on revolving credit facility	750,000
Deferred financing fees, gross	5,328	4,593
Accumulated amortization of deferred financing fees	$ 5,240	$ 4,072

Summary of Significant Accoun_7

Summary of Significant Accounting Policies - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) joint_venture property segment	Dec. 31, 2022 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	2
Number of properties (in properties) | property	152
Number of business segments | segment	1
Mortgage Note Payable
Schedule of Equity Method Investments [Line Items]
Principal balance | $	$ 177,320
Joint Venture Property 1
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	51%
Joint Venture Property 2
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	50%
Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	2
Number of properties (in properties) | property	3
Unconsolidated Joint Ventures | Joint Venture Property 1
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	51%
Unconsolidated Joint Ventures | Joint Venture Property 2
Schedule of Equity Method Investments [Line Items]
Percentage of ownership interest	50%
Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of joint ventures | joint_venture	2
Number of properties (in properties) | property	3
Unconsolidated Joint Ventures | Mortgage Note Payable
Schedule of Equity Method Investments [Line Items]
Principal balance | $	$ 82,000	$ 82,000

Per Common Share Amounts - Inco

Per Common Share Amounts - Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerators:
Net loss	$ (69,432)	$ (6,109)	$ (8,180)
Income attributable to unvested participating securities	(305)	(427)	0
Net loss used in calculating earnings per share	$ (69,737)	$ (6,536)	$ (8,180)
Denominators:
Weighted average common shares for basic earnings per share (in shares)	48,389	48,278	48,195
Weighted average common shares outstanding (diluted) (in shares)	48,389	48,278	48,195
Net income (loss) per common share - basic (in dollars per share)	$ (1.44)	$ (0.14)	$ (0.17)
Net income (loss) per common share - diluted (in dollars per share)	$ (1.44)	$ (0.14)	$ (0.17)
Antidilutive securities (in shares)			34

Real Estate Properties - Real E

Real Estate Properties - Real Estate Properties Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) ft² joint_venture property lease	Dec. 31, 2022 USD ($)	Dec. 31, 2021 ft² property
Real Estate Properties [Line Items]
Number of properties (in properties) | property	152
Area of properties (in square feet) | ft²			926,000
Real estate aggregate undepreciated carrying value | $	$ 4,065,679	$ 3,936,074
Number of joint ventures | joint_venture	2
Number of leases entered | lease	75
Rentable square feet (in sqft) | ft²	1,698,000
Weighted average lease term	8 years 6 months
Expenditures committed on leases | $	$ 82,202
Operating leases committed expenditures on leases executed in period committed but unspent tenant related obligations | $	$ 109,309
Unconsolidated Joint Ventures
Real Estate Properties [Line Items]
Number of properties (in properties) | property	3
Area of properties (in square feet) | ft²	468,000
Number of joint ventures | joint_venture	2
Joint Venture Property 1
Real Estate Properties [Line Items]
Percentage of ownership interest	51%
Joint Venture Property 2
Real Estate Properties [Line Items]
Percentage of ownership interest	50%
Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Number of properties (in properties) | property	1		2
Area of properties (in square feet) | ft²	248,000
Continuing Operations
Real Estate Properties [Line Items]
Area of properties (in square feet) | ft²	20,541,000
Real estate aggregate undepreciated carrying value | $	$ 4,095,010
Continuing Operations | Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Carrying value | $	$ 29,331

Real Estate Properties - Acquis

Real Estate Properties - Acquisition Activities (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2021 USD ($) ft² property
Business Acquisition [Line Items]
Number of properties acquired | property		3
Rentable square feet (in square feet) | ft²		926,000
Asset acquisition, consideration transferred	$ 2,750	$ 576,478
Purchase price adjustments		1,761
Acquisition related costs		1,264
Assumed Real Estate Lease Obligations		(9,088)
Adjustment for estimated tax liability		13,031
Land
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		72,078
Buildings and Improvements
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		404,024
Acquired Real Estate Leases
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		$ 109,464
Chicago, IL
Business Acquisition [Line Items]
Number of properties acquired | property		1
Rentable square feet (in square feet) | ft²		531,000
Asset acquisition, consideration transferred		$ 368,331
Assumed Real Estate Lease Obligations		(9,088)
Chicago, IL | Land
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		42,935
Chicago, IL | Buildings and Improvements
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		258,348
Chicago, IL | Acquired Real Estate Leases
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		$ 76,136
Atlanta, GA
Business Acquisition [Line Items]
Number of properties acquired | property		1
Rentable square feet (in square feet) | ft²		346,000
Asset acquisition, consideration transferred		$ 180,602
Assumed Real Estate Lease Obligations		0
Atlanta, GA | Land
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		13,040
Atlanta, GA | Buildings and Improvements
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		135,459
Atlanta, GA | Acquired Real Estate Leases
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		$ 32,103
Boston, MA
Business Acquisition [Line Items]
Number of properties acquired | property		1
Rentable square feet (in square feet) | ft²		49,000
Asset acquisition, consideration transferred		$ 27,545
Assumed Real Estate Lease Obligations		0
Boston, MA | Land
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		16,103
Boston, MA | Buildings and Improvements
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		10,217
Boston, MA | Acquired Real Estate Leases
Business Acquisition [Line Items]
Asset acquisition, consideration transferred		$ 1,225

Real Estate Properties - Dispos

Real Estate Properties - Disposition Activities (Details) $ in Thousands		9 Months Ended	12 Months Ended
	Feb. 14, 2024 USD ($)	Sep. 30, 2021 USD ($) property	Dec. 31, 2023 USD ($) ft² property	Dec. 31, 2022 USD ($) ft² property	Dec. 31, 2021 USD ($) ft² property parcel_of_land
Real Estate Properties [Line Items]
Number of properties (in properties) | property			152
Rentable square feet (in square feet) | ft²					926,000
Gain (Loss) on Sale of Real Estate			$ 3,780	$ 11,001	$ 78,354
Loss on impairment of real estate			$ 11,299	$ 21,820	$ 62,420
Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			8	18	6
Rentable square feet (in square feet) | ft²			553,000	2,326,000	2,565,000
Gross Sales Price, Excluding Closing Costs			$ 44,874	$ 211,020	$ 226,915
Gain (Loss) on Sale of Real Estate			$ 3,780	11,001	78,354
Loss on impairment of real estate				$ 21,820	$ 45,196
Disposal Group, Disposed of by Sale | Subsequent Event
Real Estate Properties [Line Items]
Gross Sales Price, Excluding Closing Costs	$ 39,000
Disposal Group, Held-for-sale, Not Discontinued Operations
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1		2
Rentable square feet (in square feet) | ft²			248,000
Gross Sales Price, Excluding Closing Costs			$ 1,777
Loss on impairment of real estate			$ 11,299		$ 6,991
Richfield, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			3
Rentable square feet (in square feet) | ft²			89,000
Gross Sales Price, Excluding Closing Costs			$ 5,350
Gain (Loss) on Sale of Real Estate			$ 2,548
Phoenix, AZ | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			107,000
Gross Sales Price, Excluding Closing Costs			$ 4,900
Gain (Loss) on Sale of Real Estate			$ 511
Vernon Hills, IL | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			100,000
Gross Sales Price, Excluding Closing Costs			$ 2,825
Gain (Loss) on Sale of Real Estate			$ (2,816)
Windsor Mill, MD | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			80,000
Gross Sales Price, Excluding Closing Costs			$ 10,500
Gain (Loss) on Sale of Real Estate			$ 244
Santa Clara, CA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			66,000
Gross Sales Price, Excluding Closing Costs			$ 16,049
Gain (Loss) on Sale of Real Estate			$ 705
Chelmsford, MA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property			1
Rentable square feet (in square feet) | ft²			111,000
Gross Sales Price, Excluding Closing Costs			$ 5,250
Gain (Loss) on Sale of Real Estate			$ 2,588
Rockville, MD | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				129,000
Gross Sales Price, Excluding Closing Costs				$ 6,750
Gain (Loss) on Sale of Real Estate				$ (72)
Chesapeake, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				2
Rentable square feet (in square feet) | ft²				172,000
Gross Sales Price, Excluding Closing Costs				$ 18,945
Gain (Loss) on Sale of Real Estate				$ 2,296
Milwaukee, WI | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				29,000
Gross Sales Price, Excluding Closing Costs				$ 3,775
Gain (Loss) on Sale of Real Estate				$ (75)
Holtsville, NY | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				264,000
Gross Sales Price, Excluding Closing Costs				$ 28,500
Gain (Loss) on Sale of Real Estate				$ 1,900
Fairfax, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				184,000
Gross Sales Price, Excluding Closing Costs				$ 19,750
Gain (Loss) on Sale of Real Estate				$ (13,537)
Houston, TX | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				206,000
Gross Sales Price, Excluding Closing Costs				$ 9,800
Gain (Loss) on Sale of Real Estate				(135)
Loss on impairment of real estate				$ 15,278
Birmingham, AL | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				3
Rentable square feet (in square feet) | ft²				448,000
Gross Sales Price, Excluding Closing Costs				$ 16,050
Gain (Loss) on Sale of Real Estate				(265)
Loss on impairment of real estate				$ 3,709
Erlanger, KY | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				86,000
Gross Sales Price, Excluding Closing Costs				$ 2,600
Gain (Loss) on Sale of Real Estate				135
Loss on impairment of real estate				$ 2,184
Chesapeake, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				2
Rentable square feet (in square feet) | ft²				214,000
Gross Sales Price, Excluding Closing Costs				$ 24,000
Gain (Loss) on Sale of Real Estate				62
Loss on impairment of real estate				$ 649
Everett, WA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				2
Rentable square feet (in square feet) | ft²				112,000
Gross Sales Price, Excluding Closing Costs				$ 31,500
Gain (Loss) on Sale of Real Estate				$ 11,959
Salem, OR | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				233,000
Gross Sales Price, Excluding Closing Costs				$ 34,250
Gain (Loss) on Sale of Real Estate				$ 5,369
Kapolei, HI | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				109,000
Gross Sales Price, Excluding Closing Costs				$ 4,000
Gain (Loss) on Sale of Real Estate				$ 2,504
Eaglewood, CO | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property				1
Rentable square feet (in square feet) | ft²				140,000
Gross Sales Price, Excluding Closing Costs				$ 11,100
Gain (Loss) on Sale of Real Estate				$ 860
Kansas City, MO | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					0
Rentable square feet (in square feet) | ft²					10,000
Gross Sales Price, Excluding Closing Costs					$ 845
Gain (Loss) on Sale of Real Estate					(63)
Loss on impairment of real estate					$ 0
Richmond, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					1
Rentable square feet (in square feet) | ft²					311,000
Gross Sales Price, Excluding Closing Costs					$ 130,000
Gain (Loss) on Sale of Real Estate					54,181
Loss on impairment of real estate					$ 0
Huntsville, AL | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					1
Rentable square feet (in square feet) | ft²					1,371,000
Gross Sales Price, Excluding Closing Costs					$ 39,000
Gain (Loss) on Sale of Real Estate					0
Loss on impairment of real estate					$ 5,383
Fresno, CA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					1
Rentable square feet (in square feet) | ft²					532,000
Gross Sales Price, Excluding Closing Costs					$ 6,000
Gain (Loss) on Sale of Real Estate					0
Loss on impairment of real estate					$ 33,902
Liverpool, NY | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					1
Rentable square feet (in square feet) | ft²					38,000
Gross Sales Price, Excluding Closing Costs					$ 650
Gain (Loss) on Sale of Real Estate					31
Loss on impairment of real estate					$ 0
Memphis, TN | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					1
Rentable square feet (in square feet) | ft²					205,000
Gross Sales Price, Excluding Closing Costs					$ 15,270
Gain (Loss) on Sale of Real Estate					287
Loss on impairment of real estate					$ 0
Stoneham, MA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					1
Rentable square feet (in square feet) | ft²					98,000
Gross Sales Price, Excluding Closing Costs					$ 6,650
Gain (Loss) on Sale of Real Estate					(282)
Loss on impairment of real estate					$ 5,911
Sterling, VA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property					0
Number of land parcels | parcel_of_land					2
Rentable square feet (in square feet) | ft²					0
Gross Sales Price, Excluding Closing Costs					$ 28,500
Gain (Loss) on Sale of Real Estate					24,200
Loss on impairment of real estate					0
Brookhaven, GA | Disposal Group, Disposed of by Sale
Real Estate Properties [Line Items]
Number of properties (in properties) | property		3
Loss on impairment of real estate		$ 10,658			$ 425

Real Estate Properties - Uncons

Real Estate Properties - Unconsolidated Joint Ventures (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jul. 31, 2023	Dec. 31, 2023 USD ($) ft² joint_venture property	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) ft²	Oct. 31, 2023 USD ($)
Real Estate [Line Items]
Number of joint ventures | joint_venture		2
Number of properties (in properties) | property		152
Rentable square feet (in square feet) | ft²				926,000
Loss on impairment of equity method investment		$ 19,183	$ 0	$ 0
Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)		7.792%
Principal balance		$ 177,320
Unconsolidated Joint Ventures
Real Estate [Line Items]
Number of joint ventures | joint_venture		2
Number of properties (in properties) | property		3
OPI Carrying Value of Investments		$ 18,128	35,129
Rentable square feet (in square feet) | ft²		468,000
Equity method investment, difference between carrying amount and underlying equity		$ 701
Unconsolidated Joint Ventures | Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)		3.93%
Principal balance		$ 82,000	82,000
Unconsolidated Joint Ventures | Prosperity Metro Plaza
Real Estate [Line Items]
Number of properties (in properties) | property		2
OPI Ownership		51%
OPI Carrying Value of Investments		$ 18,128	19,237
Rentable square feet (in square feet) | ft²		346,000
Unconsolidated Joint Ventures | Prosperity Metro Plaza | Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)		4.09%
Principal balance		$ 50,000	50,000
Unconsolidated Joint Ventures | 1750 H Street, NW
Real Estate [Line Items]
Number of properties (in properties) | property		1
OPI Ownership		50%
OPI Carrying Value of Investments		$ 0	15,892
Rentable square feet (in square feet) | ft²		122,000
Loss on impairment of equity method investment		$ 19,183
Unconsolidated Joint Ventures | 1750 H Street, NW | Joint Venture Partner
Real Estate [Line Items]
Capital call funding requirement					$ 600
Unconsolidated Joint Ventures | 1750 H Street, NW | Mortgage Note Payable
Real Estate [Line Items]
Interest rate (as a percent)		3.69%
Principal balance		$ 32,000	$ 32,000
Debt instrument extension term	3 years

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) tenant	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Lessee, Lease, Description [Line Items]
Straight line rent adjustments	$ 26,194	$ 10,830	$ 15,368
Straight line rent receivables	112,440	86,305
Variable lease, income	88,173	83,103	85,107
Tenant reimbursement income	$ 82,885	$ 78,388	81,295
Lease expense			$ 79
Lessor, Operating Lease, Payment to be Received
Lessee, Lease, Description [Line Items]
Number of government tenants with the right to terminate their leases | tenant	8
Lessor, Operating Lease, Payment to be Received | Tenant with Exercisable Termination Rights | Tenant Concentration
Lessee, Lease, Description [Line Items]
Concentration risk, percentage	1.80%
2024	1.40%
2025	2.50%
2026	2.40%
2027	2%
2028	6.10%
2029	2%
2030	2.60%
2031	1%
2032	0.80%
2034	1.40%
2035	4.40%
2036	0.60%
2037	0.60%
2040	2.30%
Lessor, Operating Lease, Payment to be Received | Fourteen Government Tenants | Tenant Concentration
Lessee, Lease, Description [Line Items]
Concentration risk, percentage	3.90%

Leases - Operating Lease Maturi

Leases - Operating Lease Maturity (Details) $ in Thousands	Dec. 31, 2023 USD ($)
Leases [Abstract]
2024	$ 378,748
2025	339,500
2026	310,205
2027	281,109
2028	243,928
Thereafter	1,428,379
Total	$ 2,981,869

Business and Property Managem_2

Business and Property Management Agreements with RMR (Details) - RMR LLC $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) employee agreement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Related Party Transaction [Line Items]
Number of employees | employee	0
Number of agreements with RMR LLC to provide management services | agreement	2
Recognized amortization of the liability	$ 603	$ 603	$ 603
Management fees as percentage of gross collected rents	3%
Construction supervision fees as percentage of construction costs	5%
Net Property Management and Construction Supervision Fees
Related Party Transaction [Line Items]
Transaction amount	$ 23,280	25,756	21,103
Reimbursement amounts	484	484	484
Net Property Management and Construction Supervision Fees | Investment Building and Building Improvements
Related Party Transaction [Line Items]
Transaction amount	8,390	9,917	4,596
Net Property Management and Construction Supervision Fees | Other Operating Income (Expense)
Related Party Transaction [Line Items]
Transaction amount	14,890	15,839	16,507
Property Operating Expenses
Related Party Transaction [Line Items]
Transaction amount	$ 25,872	24,371	24,766
Transition Services
Related Party Transaction [Line Items]
Duration of transition services	120 days
Net Business Management Fees
Related Party Transaction [Line Items]
Transaction amount	$ 14,751	$ 17,376	$ 18,637
Amended And Restate Business Management Agreement
Related Party Transaction [Line Items]
Percentage applied on average historical cost of real estate investment properties acquired	0.50%
Base management fee payable as percentage of average historical cost of real estate investments	0.70%
Percentage of average closing stock price on stock exchange	0.70%
Management fee payable as percentage of average market capitalization exceeding specified amount	0.50%
Percentage for limitation and adjustments of incentive management fee payable	12%
Measurement period for incentive management fee	3 years
Average closing price of our common shares, consecutive trading days	10 days
Highest average closing price of our common shares, final consecutive trading days	30 days
Percentage for limitation and adjustments of incentive management fee payable, minimum total return per share percentage change	5%
Percentage of base business management fee payable in common shares	1.50%
Amended And Restate Business Management Agreement | Up C Transaction
Related Party Transaction [Line Items]
Written notice for convenience	60 days
Window of written notice after calendar year	60 days
Window for written notice after change of control	12 months
Remaining termination fee term	10 years
Amended And Restate Business Management Agreement | Maximum
Related Party Transaction [Line Items]
Threshold amount of real estate investments	$ 250,000
Threshold amount of average market capitalization	$ 250,000
Percentage for limitation and adjustments of incentive management fee payable, total return per share percentage, reduction	5%
Amended And Restate Business Management Agreement | Maximum | Up C Transaction
Related Party Transaction [Line Items]
Termination fee term	20 years
Amended And Restate Business Management Agreement | Minimum
Related Party Transaction [Line Items]
Threshold amount of real estate investments	$ 250,000
Base management fee payable average market capitalization	$ 250,000
Percentage for limitation and adjustments of incentive management fee payable, total return per share percentage, reduction	2%
Amended And Restate Business Management Agreement | Minimum | Up C Transaction
Related Party Transaction [Line Items]
Termination fee term	19 years

Related Person Transactions (De

Related Person Transactions (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2021 USD ($) ft² renewal_option	Dec. 31, 2023 USD ($) agreement	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($) ft²
Related Party Transaction [Line Items]
Rental income		$ 533,553	$ 554,275	$ 576,482
Rentable square feet (in square feet) | ft²				926,000
Acquisition and transaction related costs		31,816	292	$ 0
Diversified Health Trust
Related Party Transaction [Line Items]
Acquisition and transaction related costs		$ 31,491
Officers and Other Employees | Common Shares | 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting period		4 years
Share-based Payment Arrangement, Tranche 1 | Officers and Other Employees | Common Shares | 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage		20%
Share-based Payment Arrangement, Tranche 2 | Officers and Other Employees | Common Shares | 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage		20%
Share-based Payment Arrangement, Tranche 3 | Officers and Other Employees | Common Shares | 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage		20%
Share-based Compensation Award, Tranche 4 | Officers and Other Employees | Common Shares | 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage		20%
Share-based Compensation Award, Tranche 5 | Officers and Other Employees | Common Shares | 2009 Award Plan
Related Party Transaction [Line Items]
Award vesting rights, percentage		20%
Related Party | RMR LLC
Related Party Transaction [Line Items]
Number of agreements with RMR LLC to provide management services | agreement		2
Rental income		$ 851	$ 1,126	$ 1,138
Related Party | Sonesta International Hotels Corporation
Related Party Transaction [Line Items]
Lease term	30 years
Rentable square feet (in square feet) | ft²	230,000
Percentage upon completion of redevelopment	55%
Number of renewal options | renewal_option	2
Renewal term	10 years
Annual base rent	$ 6,436
Deferred payment plan period	18 months
Annual percentage increase	10%
Annual base rent increase	5 years
Tenant improvements		$ 66,000

Concentration (Details)

Concentration (Details) - property	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Concentration Risk [Line Items]
Number of properties (in properties)	152
Number of states in which acquired properties located	30
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Tenant Concentration | U S Government, State Governments, and Other Governments
Concentration Risk [Line Items]
Concentration risk, percentage	27.50%	28.50%	28.90%
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Tenant Concentration | U.S. Government
Concentration Risk [Line Items]
Concentration risk, percentage	19.50%	19.70%	19.50%
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Geographic Concentration Risk | California
Concentration Risk [Line Items]
Concentration risk, percentage	11.80%
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Geographic Concentration Risk | Virginia
Concentration Risk [Line Items]
Concentration risk, percentage	11.60%
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Geographic Concentration Risk | Illinois
Concentration Risk [Line Items]
Concentration risk, percentage	10.60%
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Geographic Concentration Risk | Washington, D.C.
Concentration Risk [Line Items]
Concentration risk, percentage	9.30%
Annualized Rental Income, Excluding Properties Classified as Discontinued Operations | Geographic Concentration Risk | Texas
Concentration Risk [Line Items]
Concentration risk, percentage	8.80%

Indebtedness - Outstanding Debt

Indebtedness - Outstanding Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Borrowings outstanding	$ 2,594,320		$ 2,457,000
Unamortized debt premiums, discounts and issuance costs	(21,711)		(24,208)
Total borrowings outstanding	$ 2,572,609		2,432,792
Senior Notes | Senior unsecured notes, 4.250% interest rate, due in 2024
Debt Instrument [Line Items]
Interest rate (as a percent)	4.25%
Borrowings outstanding	$ 350,000		350,000
Senior Notes | Senior unsecured notes, 4.500% interest rate, due in 2025
Debt Instrument [Line Items]
Interest rate (as a percent)	4.50%
Borrowings outstanding	$ 650,000		650,000
Senior Notes | Senior unsecured notes, 2.650% interest rate, due in 2026
Debt Instrument [Line Items]
Interest rate (as a percent)	2.65%
Borrowings outstanding	$ 300,000		300,000
Senior Notes | Senior unsecured notes, 2.400% interest rate, due in 2027
Debt Instrument [Line Items]
Interest rate (as a percent)	2.40%
Borrowings outstanding	$ 350,000		350,000
Senior Notes | Senior unsecured notes, 3.450% interest rate, due in 2031
Debt Instrument [Line Items]
Interest rate (as a percent)	3.45%
Borrowings outstanding	$ 400,000		400,000
Senior Notes | Senior unsecured notes, 6.375% interest rate, due in 2050
Debt Instrument [Line Items]
Interest rate (as a percent)	6.375%
Borrowings outstanding	$ 162,000		162,000
Mortgage Note Payable
Debt Instrument [Line Items]
Interest rate (as a percent)	7.792%
Total borrowings outstanding	$ 177,320
Mortgage Note Payable | Mortgage note payable, 3.700% interest rate, due in 2023
Debt Instrument [Line Items]
Interest rate (as a percent)	3.70%	3.70%
Borrowings outstanding	$ 0		50,000
Mortgage Note Payable | Mortgage note payable, 8.272% interest rate, due in 2028
Debt Instrument [Line Items]
Interest rate (as a percent)	8.272%
Borrowings outstanding	$ 42,700		0
Mortgage Note Payable | Mortgage note payable, 8.139% interest rate, due in 2028
Debt Instrument [Line Items]
Interest rate (as a percent)	8.139%
Borrowings outstanding	$ 26,340		0
Mortgage Note Payable | Mortgage note payable, 7.671% interest rate, due in 2028
Debt Instrument [Line Items]
Interest rate (as a percent)	7.671%
Borrowings outstanding	$ 54,300		0
Mortgage Note Payable | Mortgage note payable, 7.210% interest rate, due in 2033
Debt Instrument [Line Items]
Interest rate (as a percent)	7.21%
Borrowings outstanding	$ 30,680		0
Mortgage Note Payable | Mortgage note payable, 7.305% interest rate, due in 2033
Debt Instrument [Line Items]
Interest rate (as a percent)	7.305%
Borrowings outstanding	$ 8,400		0
Mortgage Note Payable | Mortgage note payable, 7.717% interest rate, due in 2033
Debt Instrument [Line Items]
Interest rate (as a percent)	7.717%
Borrowings outstanding	$ 14,900		0
Revolving credit facility | Line of Credit
Debt Instrument [Line Items]
Borrowings outstanding	$ 205,000		$ 195,000

Indebtedness - Narrative (Detai

Indebtedness - Narrative (Details) $ / shares in Units, $ in Thousands			1 Months Ended			12 Months Ended
	Feb. 15, 2024 USD ($) property	Feb. 14, 2024 USD ($)	Mar. 31, 2024 USD ($)	Jan. 31, 2024 USD ($) property $ / shares	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($) property $ / shares	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Unsecured revolving credit facility						$ 205,000	$ 195,000
Borrowings outstanding						2,594,320	2,457,000
Repayments of mortgage notes payable						50,000	47,617	$ 72,541
Proceeds from Issuance of senior notes						0	$ 0	$ 1,041,809
Line of Credit
Debt Instrument [Line Items]
Maximum borrowing capacity on revolving credit facility						$ 750,000
Distribution rate (in dollars per share) | $ / shares						$ 0.01
Commitment fee percentage						0.30%
Interest rate (as a percent)						6.90%	5.40%
Weighted average annual interest rate						6.50%	4%	1.20%
Line of Credit | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Interest rate premium (as a percent)						1.45%
Line of Credit | Subsequent Event
Debt Instrument [Line Items]
Distribution rate (in dollars per share) | $ / shares				$ 0.01
Line of Credit | Subsequent Event | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Debt Instrument [Line Items]
Interest rate premium (as a percent)		3.50%
Line of Credit | Revolving credit facility
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property						19
Book value of properties collateralized						$ 941,937
Borrowings outstanding						$ 205,000	$ 195,000
Line of Credit | Revolving credit facility | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity on revolving credit facility				$ 325,000
Number of properties used to secured mortgage note | property				19
Debt instrument extension term				1 year
Commitment fee percentage		0.35%
Unsecured revolving credit facility		$ 132,000
Available borrowings		193,000
Line of Credit | Secured Debt
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property						19
Book value of properties collateralized						$ 941,937
Line of Credit | Secured Debt | Subsequent Event
Debt Instrument [Line Items]
Principal balance				$ 100,000
Number of properties used to secured mortgage note | property				19
Secured Debt | Subsequent Event
Debt Instrument [Line Items]
Principal balance				$ 100,000
Borrowings outstanding		$ 100,000
Mortgage Note Payable
Debt Instrument [Line Items]
Principal balance						177,320
Book value of properties collateralized						$ 239,754
Interest rate (as a percent)						7.792%
Mortgage Note Payable | Mortgage note payable, 3.700% interest rate, due in 2023
Debt Instrument [Line Items]
Interest rate (as a percent)					3.70%	3.70%
Borrowings outstanding						$ 0	50,000
Repayments of mortgage notes payable					$ 50,000
Senior Notes | Senior secured notes, 9.000% interest rate, due in 2029
Debt Instrument [Line Items]
Book value of properties collateralized						$ 574,291
Senior Notes | Senior unsecured notes, 4.250% interest rate, due in 2024
Debt Instrument [Line Items]
Interest rate (as a percent)						4.25%
Borrowings outstanding						$ 350,000	350,000
Senior Notes | Senior unsecured notes, 4.250% interest rate, due in 2024 | Forecast
Debt Instrument [Line Items]
Interest rate (as a percent)			4.25%
Extinguishment of debt, amount			$ 350,000
Senior Notes | Senior unsecured notes, 4.500% interest rate, due in 2025
Debt Instrument [Line Items]
Interest rate (as a percent)						4.50%
Borrowings outstanding						$ 650,000	$ 650,000
Senior Notes | Subsequent Event | Senior secured notes, 9.000% interest rate, due in 2029
Debt Instrument [Line Items]
Principal balance	$ 300,000
Number of properties used to secured mortgage note | property	17
Interest rate (as a percent)	9%
Proceeds from Issuance of senior notes	$ 271,500

Indebtedness - Mortgage Note Is

Indebtedness - Mortgage Note Issuances (Details) - Dec. 31, 2023 $ in Thousands	USD ($)	Total	property	mortgage_note
Debt Instrument [Line Items]
Number of mortgage notes			6	6
Mortgage Note Payable
Debt Instrument [Line Items]
Principal balance	$ 177,320
Interest rate (as a percent)		7.792%
Book value of properties collateralized	239,754
Mortgage Note Payable | Mortgage note payable, 7.210% interest rate, due in 2033
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property			1
Principal balance	30,680
Interest rate (as a percent)		7.21%
Book value of properties collateralized	36,807
Mortgage Note Payable | Mortgage note payable, 8.139% interest rate, due in 2028
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property			1
Principal balance	26,340
Interest rate (as a percent)		8.139%
Book value of properties collateralized	52,342
Mortgage Note Payable | Mortgage note payable, 8.272% interest rate, due in 2028
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property			1
Principal balance	42,700
Interest rate (as a percent)		8.272%
Book value of properties collateralized	42,834
Mortgage Note Payable | Mortgage note payable, 7.305% interest rate, due in 2033
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property			1
Principal balance	8,400
Interest rate (as a percent)		7.305%
Book value of properties collateralized	19,035
Mortgage Note Payable | Mortgage note payable, 7.717% interest rate, due in 2033
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property			1
Principal balance	14,900
Interest rate (as a percent)		7.717%
Book value of properties collateralized	23,908
Mortgage Note Payable | Mortgage note payable, 7.671% interest rate, due in 2028
Debt Instrument [Line Items]
Number of properties used to secured mortgage note | property			2
Principal balance	54,300
Interest rate (as a percent)		7.671%
Book value of properties collateralized	$ 64,828

Indebtedness - Future Principal

Indebtedness - Future Principal Payments (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Debt Disclosure [Abstract]
2024	$ 555,000
2025	650,000
2026	300,000
2027	350,000
2028	123,487
Thereafter	615,833
Total	2,594,320	$ 2,457,000
Unamortized debt premiums, discounts and issuance	21,711	24,208
Total debt outstanding	$ 2,572,609	$ 2,432,792

Fair Value of Assets and Liab_3

Fair Value of Assets and Liabilities - Asset Measured at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Fair Value of Assets and Liabilities
Loss on impairment of real estate	$ 11,299	$ 21,820	$ 62,420
Loss on impairment of equity method investment	19,183	$ 0	0
1750 H Street, NW | Unconsolidated Joint Ventures
Fair Value of Assets and Liabilities
Loss on impairment of equity method investment	19,183
Disposal Group, Held-for-sale, Not Discontinued Operations
Fair Value of Assets and Liabilities
Loss on impairment of real estate	11,299		$ 6,991
Gross Sales Price, Excluding Closing Costs	1,777
Fair Value, Nonrecurring
Fair Value of Assets and Liabilities
Assets of properties held for sale	39,000
Fair Value, Nonrecurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value of Assets and Liabilities
Assets of properties held for sale	0
Fair Value, Nonrecurring | Significant Other Observable Inputs (Level 2)
Fair Value of Assets and Liabilities
Assets of properties held for sale	39,000
Fair Value, Nonrecurring | Significant Unobservable Inputs (Level 3)
Fair Value of Assets and Liabilities
Assets of properties held for sale	$ 0

Fair Value of Assets and Liab_4

Fair Value of Assets and Liabilities - Financial Instruments (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) property	Dec. 31, 2021 USD ($)	Dec. 31, 2023 property	Dec. 31, 2023	Dec. 31, 2023 mortgage_note
Fair Value of Financial Instruments
Senior notes		$ 2,195,478	$ 2,187,875
Mortgage notes payable		172,131	49,917
Unamortized debt premiums, discounts and issuance		21,711	24,208
Number of properties (in properties) | property					152
Repayments of mortgage notes payable		50,000	47,617	$ 72,541
Number of mortgage notes					6		6
Long-term debt		2,572,609	$ 2,432,792
Mortgage note payable, 3.700% interest rate, due in 2023
Fair Value of Financial Instruments
Number of properties (in properties) | property			1
Carrying Amount
Fair Value of Financial Instruments
Fair value of financial instruments		2,367,609	$ 2,237,792
Fair Value
Fair Value of Financial Instruments
Fair value of financial instruments		1,686,825	1,840,543
Senior Notes and Mortgages
Fair Value of Financial Instruments
Unamortized debt premiums, discounts and issuance		21,711	24,208
Senior Notes | Senior unsecured notes, 4.250% interest rate, due in 2024
Fair Value of Financial Instruments
Interest rate (as a percent)						4.25%
Senior Notes | Senior unsecured notes, 4.500% interest rate, due in 2025
Fair Value of Financial Instruments
Interest rate (as a percent)						4.50%
Senior Notes | Senior unsecured notes, 2.650% interest rate, due in 2026
Fair Value of Financial Instruments
Interest rate (as a percent)						2.65%
Senior Notes | Senior unsecured notes, 2.400% interest rate, due in 2027
Fair Value of Financial Instruments
Interest rate (as a percent)						2.40%
Senior Notes | Senior unsecured notes, 3.450% interest rate, due in 2031
Fair Value of Financial Instruments
Interest rate (as a percent)						3.45%
Senior Notes | Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Interest rate (as a percent)						6.375%
Senior Notes | Carrying Amount | Senior unsecured notes, 4.250% interest rate, due in 2024
Fair Value of Financial Instruments
Senior notes		349,144	346,863
Senior Notes | Carrying Amount | Senior unsecured notes, 4.500% interest rate, due in 2025
Fair Value of Financial Instruments
Senior notes		646,266	642,818
Senior Notes | Carrying Amount | Senior unsecured notes, 2.650% interest rate, due in 2026
Fair Value of Financial Instruments
Senior notes		298,464	297,839
Senior Notes | Carrying Amount | Senior unsecured notes, 2.400% interest rate, due in 2027
Fair Value of Financial Instruments
Senior notes		348,086	347,466
Senior Notes | Carrying Amount | Senior unsecured notes, 3.450% interest rate, due in 2031
Fair Value of Financial Instruments
Senior notes		396,614	396,178
Senior Notes | Carrying Amount | Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Senior notes		156,904	156,711
Senior Notes | Fair Value | Senior unsecured notes, 4.250% interest rate, due in 2024
Fair Value of Financial Instruments
Senior notes		331,510	331,601
Senior Notes | Fair Value | Senior unsecured notes, 4.500% interest rate, due in 2025
Fair Value of Financial Instruments
Senior notes		510,445	589,388
Senior Notes | Fair Value | Senior unsecured notes, 2.650% interest rate, due in 2026
Fair Value of Financial Instruments
Senior notes		185,934	232,770
Senior Notes | Fair Value | Senior unsecured notes, 2.400% interest rate, due in 2027
Fair Value of Financial Instruments
Senior notes		196,147	256,606
Senior Notes | Fair Value | Senior unsecured notes, 3.450% interest rate, due in 2031
Fair Value of Financial Instruments
Senior notes		199,060	268,004
Senior Notes | Fair Value | Senior unsecured notes, 6.375% interest rate, due in 2050
Fair Value of Financial Instruments
Senior notes		83,916	113,075
Mortgages
Fair Value of Financial Instruments
Interest rate (as a percent)						7.792%
Long-term debt		177,320
Mortgages | Mortgage note payable, 3.700% interest rate, due in 2023
Fair Value of Financial Instruments
Interest rate (as a percent)	3.70%					3.70%
Repayments of mortgage notes payable	$ 50,000
Mortgages | Carrying Amount
Fair Value of Financial Instruments
Mortgage notes payable		172,131	49,917
Mortgages | Fair Value
Fair Value of Financial Instruments
Mortgage notes payable		$ 179,813	$ 49,099

Shareholders' Equity - Share Aw

Shareholders' Equity - Share Awards (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) installment shares	Dec. 31, 2022 USD ($) shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 shares
2009 Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	241,800	172,700	145,800
Number of installments | installment	5
Unvested shares (in shares)	288,681	231,301	182,224	157,521
2024 (in shares)	98,241
2025 (in shares)	83,620
2026 (in shares)	65,160
2027 (in shares)	41,660
Estimated future compensation expense for the unvested shares | $	$ 3,042
Weighted average period of recognition of compensation expenses (in years)	23 months
Compensation expense | $	$ 2,257	$ 2,905	$ 2,868
Shares available for issuance under plan (in shares)	657,860
Officers and Other Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Issuance of shares, net (in shares)	210,300	141,200	117,800
Issuance of shares, net | $	$ 1,211	$ 2,470	$ 2,994
Trustees | 2009 Award Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted (in shares)	3,500	3,500	3,500
Aggregate market value of shares awarded | $	$ 249	$ 593	$ 837
Market value of common shares awarded to each trustee (in dollars) | $	$ 28	$ 66	$ 105

Shareholders' Equity - Unvested

Shareholders' Equity - Unvested Shares Activity (Details) - 2009 Award Plan - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Number of Shares
Unvested at the beginning of the period (in shares)	231,301	182,224	157,521
Granted (in shares)	241,800	172,700	145,800
Forfeited (in shares)	(3,700)	(1,900)	(700)
Vested (in shares)	(180,720)	(121,723)	(120,397)
Unvested at the end of the period (in shares)	288,681	231,301	182,224
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share)	$ 21.47	$ 26.23	$ 29.26
Granted (in dollars per share)	6.04	17.74	26.28
Forfeited (in dollars per share)	17.31	25.97	25.97
Vested (in dollars per share)	16	23.24	30.24
Unvested at the end of the period (in dollars per share)	$ 12.01	$ 21.47	$ 26.23

Shareholders' Equity - Share Re

Shareholders' Equity - Share Repurchases/Sale of Shares (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Jan. 11, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Class of Stock [Line Items]
Share repurchases (in shares)		48,329	30,821	37,801
Stock repurchase price (in dollars per share)		$ 6.08	$ 17.54	$ 26.55
Subsequent Event
Class of Stock [Line Items]
Common distributions declared (in dollars per share)	$ 0.01
Dividends payable	$ 490

Shareholders' Equity - Distribu

Shareholders' Equity - Distribution (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Equity [Abstract]
Annual Per Share Distribution (in dollars per share)	$ 1.30	$ 2.20	$ 2.20
Total Distributions	$ 63,187	$ 106,630	$ 106,368
Characterization of Distribution, Return of Capital	100%	62.68%	0%
Characterization of Distribution, Ordinary Income	0%	37.32%	100%
Characterization of Distribution, Quality Dividend	0%	0%	0%

SCHEDULE III REAL ESTATE AND _2

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) property	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Real estate and accumulated depreciation
Number of Properties | property	151
Encumbrances	$ 172,131
Initial Cost to Company
Land	785,646
Buildings and Equipment	2,492,042
Costs Capitalized Subsequent to Acquisition	792,516
Impairment/ Writedowns	(4,525)
Cost amount carried at Close of Period
Land	786,310
Buildings and Equipment	3,279,369
Total	4,065,679	$ 3,936,074	$ 3,911,086	$ 3,522,143
Accumulated Depreciation	$ (650,179)	$ (561,458)	$ (495,912)	$ (451,914)
445 Jan Davis Drive, Huntsville, AL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,501
Buildings and Equipment	1,492
Costs Capitalized Subsequent to Acquisition	0
Cost amount carried at Close of Period
Land	1,501
Buildings and Equipment	1,492
Total	2,993
Accumulated Depreciation	$ (199)
131 Clayton Street, Montgomery, AL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 920
Buildings and Equipment	9,084
Costs Capitalized Subsequent to Acquisition	417
Cost amount carried at Close of Period
Land	920
Buildings and Equipment	9,501
Total	10,421
Accumulated Depreciation	$ (2,957)
4344 Carmichael Road, Montgomery, AL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,374
Buildings and Equipment	11,658
Costs Capitalized Subsequent to Acquisition	571
Cost amount carried at Close of Period
Land	1,374
Buildings and Equipment	12,229
Total	13,603
Accumulated Depreciation	$ (3,109)
15451 North 28th Avenue, Phoenix, AZ
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,917
Buildings and Equipment	7,416
Costs Capitalized Subsequent to Acquisition	1,239
Cost amount carried at Close of Period
Land	1,917
Buildings and Equipment	8,655
Total	10,572
Accumulated Depreciation	$ (2,016)
711 S 14th Avenue, Safford, AZ
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 460
Buildings and Equipment	11,708
Costs Capitalized Subsequent to Acquisition	903
Impairment/ Writedowns	(4,440)
Cost amount carried at Close of Period
Land	364
Buildings and Equipment	8,267
Total	8,631
Accumulated Depreciation	$ (1,703)
Regents Center, Tempe, AZ
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 4,121
Buildings and Equipment	3,042
Costs Capitalized Subsequent to Acquisition	354
Cost amount carried at Close of Period
Land	4,121
Buildings and Equipment	3,396
Total	7,517
Accumulated Depreciation	$ (841)
Campbell Place, Carlsbad, CA
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 5,769
Buildings and Equipment	3,871
Costs Capitalized Subsequent to Acquisition	7,595
Cost amount carried at Close of Period
Land	5,769
Buildings and Equipment	11,466
Total	17,235
Accumulated Depreciation	$ (3,407)
Folsom Corporate Center, Folsom, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,904
Buildings and Equipment	5,583
Costs Capitalized Subsequent to Acquisition	1,587
Cost amount carried at Close of Period
Land	2,904
Buildings and Equipment	7,170
Total	10,074
Accumulated Depreciation	$ (1,238)
Bayside Technology Park, Fremont, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 10,784
Buildings and Equipment	648
Costs Capitalized Subsequent to Acquisition	255
Cost amount carried at Close of Period
Land	10,784
Buildings and Equipment	903
Total	11,687
Accumulated Depreciation	$ (154)
10949 N. Mather Boulevard, Rancho Cordova, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 562
Buildings and Equipment	16,923
Costs Capitalized Subsequent to Acquisition	1,052
Cost amount carried at Close of Period
Land	562
Buildings and Equipment	17,975
Total	18,537
Accumulated Depreciation	$ (4,675)
11020 Sun Center Drive, Rancho Cordova, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,466
Buildings and Equipment	8,797
Costs Capitalized Subsequent to Acquisition	1,543
Cost amount carried at Close of Period
Land	1,466
Buildings and Equipment	10,340
Total	11,806
Accumulated Depreciation	$ (2,174)
100 Redwood Shores Parkway, Redwood City, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 14,454
Buildings and Equipment	7,721
Costs Capitalized Subsequent to Acquisition	0
Cost amount carried at Close of Period
Land	14,454
Buildings and Equipment	7,721
Total	22,175
Accumulated Depreciation	$ (1,071)
3875 Atherton Road, Rocklin, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 177
Buildings and Equipment	853
Costs Capitalized Subsequent to Acquisition	479
Cost amount carried at Close of Period
Land	177
Buildings and Equipment	1,332
Total	1,509
Accumulated Depreciation	$ (140)
801 K Street, Sacramento, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,688
Buildings and Equipment	61,994
Costs Capitalized Subsequent to Acquisition	10,472
Cost amount carried at Close of Period
Land	4,688
Buildings and Equipment	72,466
Total	77,154
Accumulated Depreciation	$ (15,524)
9815 Goethe Road, Sacramento, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,450
Buildings and Equipment	9,465
Costs Capitalized Subsequent to Acquisition	2,181
Cost amount carried at Close of Period
Land	1,450
Buildings and Equipment	11,646
Total	13,096
Accumulated Depreciation	$ (3,400)
Capitol Place, Sacramento, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,290
Buildings and Equipment	35,891
Costs Capitalized Subsequent to Acquisition	8,674
Cost amount carried at Close of Period
Land	2,290
Buildings and Equipment	44,565
Total	46,855
Accumulated Depreciation	$ (15,686)
4560 Viewridge Road, San Diego, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,269
Buildings and Equipment	18,316
Costs Capitalized Subsequent to Acquisition	5,294
Cost amount carried at Close of Period
Land	4,347
Buildings and Equipment	23,532
Total	27,879
Accumulated Depreciation	$ (14,798)
2115 O'Nel Drive, San Jose, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 12,305
Buildings and Equipment	5,062
Costs Capitalized Subsequent to Acquisition	385
Cost amount carried at Close of Period
Land	12,305
Buildings and Equipment	5,447
Total	17,752
Accumulated Depreciation	$ (765)
North First Street, San Jose, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 8,311
Buildings and Equipment	4,003
Costs Capitalized Subsequent to Acquisition	443
Cost amount carried at Close of Period
Land	8,311
Buildings and Equipment	4,446
Total	12,757
Accumulated Depreciation	$ (729)
Rio Robles Drive, San Jose, CA
Real estate and accumulated depreciation
Number of Properties | property	3
Encumbrances	$ 8,064
Initial Cost to Company
Land	23,687
Buildings and Equipment	13,698
Costs Capitalized Subsequent to Acquisition	17,061
Cost amount carried at Close of Period
Land	23,687
Buildings and Equipment	30,759
Total	54,446
Accumulated Depreciation	$ (3,779)
2450 and 2500 Walsh Avenue, Santa Clara, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 6,687
Buildings and Equipment	8,326
Costs Capitalized Subsequent to Acquisition	280
Cost amount carried at Close of Period
Land	6,687
Buildings and Equipment	8,606
Total	15,293
Accumulated Depreciation	$ (1,181)
3250 and 3260 Jay Street, Santa Clara, CA
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 19,899
Buildings and Equipment	14,051
Costs Capitalized Subsequent to Acquisition	114
Cost amount carried at Close of Period
Land	19,899
Buildings and Equipment	14,165
Total	34,064
Accumulated Depreciation	$ (1,949)
603 San Juan Avenue, Stockton, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 563
Buildings and Equipment	5,470
Costs Capitalized Subsequent to Acquisition	206
Cost amount carried at Close of Period
Land	563
Buildings and Equipment	5,676
Total	6,239
Accumulated Depreciation	$ (1,586)
350 West Java Drive, Sunnyvale, CA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 24,609
Buildings and Equipment	462
Costs Capitalized Subsequent to Acquisition	978
Cost amount carried at Close of Period
Land	24,609
Buildings and Equipment	1,440
Total	26,049
Accumulated Depreciation	$ (148)
7958 South Chester Street, Centennial, CO
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 6,682
Buildings and Equipment	7,153
Costs Capitalized Subsequent to Acquisition	1,801
Cost amount carried at Close of Period
Land	6,682
Buildings and Equipment	8,954
Total	15,636
Accumulated Depreciation	$ (1,265)
350 Spectrum Loop, Colorado Springs, CO
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 3,650
Buildings and Equipment	7,732
Costs Capitalized Subsequent to Acquisition	594
Cost amount carried at Close of Period
Land	3,650
Buildings and Equipment	8,326
Total	11,976
Accumulated Depreciation	$ (1,205)
12795 West Alameda Parkway, Lakewood, CO
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,640
Buildings and Equipment	23,777
Costs Capitalized Subsequent to Acquisition	1,508
Cost amount carried at Close of Period
Land	2,640
Buildings and Equipment	25,285
Total	27,925
Accumulated Depreciation	$ (8,849)
Corporate Center, Lakewood, CO
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 2,887
Buildings and Equipment	27,537
Costs Capitalized Subsequent to Acquisition	2,613
Cost amount carried at Close of Period
Land	2,887
Buildings and Equipment	30,150
Total	33,037
Accumulated Depreciation	$ (15,398)
11 Dupont Circle, NW, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 28,255
Buildings and Equipment	44,743
Costs Capitalized Subsequent to Acquisition	19,249
Cost amount carried at Close of Period
Land	28,255
Buildings and Equipment	63,992
Total	92,247
Accumulated Depreciation	$ (12,479)
1211 Connecticut Avenue, NW, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 30,388
Buildings and Equipment	24,667
Costs Capitalized Subsequent to Acquisition	4,855
Cost amount carried at Close of Period
Land	30,388
Buildings and Equipment	29,522
Total	59,910
Accumulated Depreciation	$ (5,821)
1401 K Street, NW, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 29,215
Buildings and Equipment	34,656
Costs Capitalized Subsequent to Acquisition	8,485
Cost amount carried at Close of Period
Land	29,215
Buildings and Equipment	43,141
Total	72,356
Accumulated Depreciation	$ (9,458)
20 Massachusetts Avenue, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 12,009
Buildings and Equipment	51,527
Costs Capitalized Subsequent to Acquisition	221,203
Cost amount carried at Close of Period
Land	12,231
Buildings and Equipment	272,508
Total	284,739
Accumulated Depreciation	$ (48,475)
440 First Street, NW, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 27,903
Buildings and Equipment	38,624
Costs Capitalized Subsequent to Acquisition	2,169
Cost amount carried at Close of Period
Land	27,903
Buildings and Equipment	40,793
Total	68,696
Accumulated Depreciation	$ (6,341)
625 Indiana Avenue, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 26,000
Buildings and Equipment	25,955
Costs Capitalized Subsequent to Acquisition	12,158
Cost amount carried at Close of Period
Land	26,000
Buildings and Equipment	38,113
Total	64,113
Accumulated Depreciation	$ (12,464)
840 First Street, NE, Washington DC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 42,727
Buildings and Equipment	73,278
Costs Capitalized Subsequent to Acquisition	2,912
Cost amount carried at Close of Period
Land	42,727
Buildings and Equipment	76,190
Total	118,917
Accumulated Depreciation	$ (12,414)
10350 NW 112th Avenue, Miami, FL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,798
Buildings and Equipment	2,757
Costs Capitalized Subsequent to Acquisition	2,354
Cost amount carried at Close of Period
Land	4,798
Buildings and Equipment	5,111
Total	9,909
Accumulated Depreciation	$ (684)
7850 Southwest 6th Court, Plantation, FL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,800
Buildings and Equipment	30,592
Costs Capitalized Subsequent to Acquisition	14,993
Cost amount carried at Close of Period
Land	4,800
Buildings and Equipment	45,585
Total	50,385
Accumulated Depreciation	$ (9,839)
8900 Grand Oak Circle, Tampa, FL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,100
Buildings and Equipment	11,773
Costs Capitalized Subsequent to Acquisition	1,661
Cost amount carried at Close of Period
Land	1,100
Buildings and Equipment	13,434
Total	14,534
Accumulated Depreciation	$ (4,219)
180 Ted Turner Drive SW, Atlanta, GA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,717
Buildings and Equipment	20,017
Costs Capitalized Subsequent to Acquisition	1,390
Cost amount carried at Close of Period
Land	5,717
Buildings and Equipment	21,407
Total	27,124
Accumulated Depreciation	$ (5,989)
1224 Hammond Drive, Atlanta GA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 13,040
Buildings and Equipment	135,459
Costs Capitalized Subsequent to Acquisition	11,583
Cost amount carried at Close of Period
Land	13,040
Buildings and Equipment	147,042
Total	160,082
Accumulated Depreciation	$ (10,789)
Corporate Square, Atlanta, GA
Real estate and accumulated depreciation
Number of Properties | property	5
Initial Cost to Company
Land	$ 3,996
Buildings and Equipment	29,763
Costs Capitalized Subsequent to Acquisition	26,570
Cost amount carried at Close of Period
Land	3,996
Buildings and Equipment	56,333
Total	60,329
Accumulated Depreciation	$ (21,009)
Executive Park, Atlanta, GA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,521
Buildings and Equipment	11,826
Costs Capitalized Subsequent to Acquisition	4,123
Cost amount carried at Close of Period
Land	1,521
Buildings and Equipment	15,949
Total	17,470
Accumulated Depreciation	$ (9,089)
One Georgia Center, Atlanta, GA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 10,250
Buildings and Equipment	27,933
Costs Capitalized Subsequent to Acquisition	20,903
Cost amount carried at Close of Period
Land	10,250
Buildings and Equipment	48,836
Total	59,086
Accumulated Depreciation	$ (13,865)
One Primerica Parkway, Duluth, GA
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 25,904
Initial Cost to Company
Land	6,927
Buildings and Equipment	22,951
Costs Capitalized Subsequent to Acquisition	40
Cost amount carried at Close of Period
Land	6,927
Buildings and Equipment	22,991
Total	29,918
Accumulated Depreciation	$ (3,181)
4712 Southpark Boulevard, Ellenwood, GA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,390
Buildings and Equipment	19,635
Costs Capitalized Subsequent to Acquisition	911
Cost amount carried at Close of Period
Land	1,390
Buildings and Equipment	20,546
Total	21,936
Accumulated Depreciation	$ (5,707)
8305 NW 62nd Avenue, Johnston, IA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,649
Buildings and Equipment	7,997
Costs Capitalized Subsequent to Acquisition	0
Cost amount carried at Close of Period
Land	2,649
Buildings and Equipment	7,997
Total	10,646
Accumulated Depreciation	$ (1,108)
1185, 1249 & 1387 S. Vinnell Way, Boise, ID
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 3,390
Buildings and Equipment	29,026
Costs Capitalized Subsequent to Acquisition	1,246
Cost amount carried at Close of Period
Land	3,390
Buildings and Equipment	30,272
Total	33,662
Accumulated Depreciation	$ (8,663)
2020 S. Arlington Heights, Arlington Heights, IL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,450
Buildings and Equipment	13,588
Costs Capitalized Subsequent to Acquisition	2,129
Cost amount carried at Close of Period
Land	1,450
Buildings and Equipment	15,717
Total	17,167
Accumulated Depreciation	$ (5,138)
1000 W. Fulton, Chicago IL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 42,935
Buildings and Equipment	252,914
Costs Capitalized Subsequent to Acquisition	528
Cost amount carried at Close of Period
Land	42,935
Buildings and Equipment	253,442
Total	296,377
Accumulated Depreciation	$ (21,274)
HUB 1415, Naperville IL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 12,333
Buildings and Equipment	20,586
Costs Capitalized Subsequent to Acquisition	23,564
Cost amount carried at Close of Period
Land	12,333
Buildings and Equipment	44,150
Total	56,483
Accumulated Depreciation	$ (7,248)
7601 and 7635 Interactive Way, Indianapolis, IN
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 3,337
Buildings and Equipment	14,522
Costs Capitalized Subsequent to Acquisition	34
Cost amount carried at Close of Period
Land	3,337
Buildings and Equipment	14,556
Total	17,893
Accumulated Depreciation	$ (1,900)
Intech Park, Indianapolis, IN
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 4,170
Buildings and Equipment	69,759
Costs Capitalized Subsequent to Acquisition	12,052
Cost amount carried at Close of Period
Land	4,170
Buildings and Equipment	81,811
Total	85,981
Accumulated Depreciation	$ (26,133)
7125 Industrial Road, Florence, KY
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,698
Buildings and Equipment	11,722
Costs Capitalized Subsequent to Acquisition	293
Cost amount carried at Close of Period
Land	1,698
Buildings and Equipment	12,015
Total	13,713
Accumulated Depreciation	$ (3,349)
251 Causeway Street, Boston, MA
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 26,851
Buildings and Equipment	36,756
Costs Capitalized Subsequent to Acquisition	5,296
Cost amount carried at Close of Period
Land	26,851
Buildings and Equipment	42,052
Total	68,903
Accumulated Depreciation	$ (9,174)
330 Billerica road, Chelmsford, MA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,477
Buildings and Equipment	0
Costs Capitalized Subsequent to Acquisition	10,246
Cost amount carried at Close of Period
Land	2,477
Buildings and Equipment	10,246
Total	12,723
Accumulated Depreciation	$ (1,924)
75 Pleasant Street, Malden, MA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,050
Buildings and Equipment	31,086
Costs Capitalized Subsequent to Acquisition	275
Cost amount carried at Close of Period
Land	1,050
Buildings and Equipment	31,361
Total	32,411
Accumulated Depreciation	$ (10,636)
25 Newport Avenue, Quincy, MA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,700
Buildings and Equipment	9,199
Costs Capitalized Subsequent to Acquisition	3,106
Cost amount carried at Close of Period
Land	2,700
Buildings and Equipment	12,305
Total	15,005
Accumulated Depreciation	$ (3,572)
314 Littleton Road, Westford, MA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,691
Buildings and Equipment	8,487
Costs Capitalized Subsequent to Acquisition	100
Cost amount carried at Close of Period
Land	5,691
Buildings and Equipment	8,587
Total	14,278
Accumulated Depreciation	$ (1,201)
Annapolis Commerce Center, Annapolis, MD
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 4,057
Buildings and Equipment	7,665
Costs Capitalized Subsequent to Acquisition	4,806
Cost amount carried at Close of Period
Land	4,057
Buildings and Equipment	12,471
Total	16,528
Accumulated Depreciation	$ (2,241)
4201 Patterson Avenue, Baltimore, MD
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 901
Buildings and Equipment	8,097
Costs Capitalized Subsequent to Acquisition	4,134
Impairment/ Writedowns	(85)
Cost amount carried at Close of Period
Land	893
Buildings and Equipment	12,154
Total	13,047
Accumulated Depreciation	$ (7,198)
7001 Columbia Gateway Drive, Columbia, MD
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,642
Buildings and Equipment	10,352
Costs Capitalized Subsequent to Acquisition	3,444
Cost amount carried at Close of Period
Land	5,642
Buildings and Equipment	13,796
Total	19,438
Accumulated Depreciation	$ (1,605)
Hillside Center, Columbia, MD
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 3,437
Buildings and Equipment	4,228
Costs Capitalized Subsequent to Acquisition	1,015
Cost amount carried at Close of Period
Land	3,437
Buildings and Equipment	5,243
Total	8,680
Accumulated Depreciation	$ (1,098)
TenThreeTwenty, Columbia, MD
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 3,126
Buildings and Equipment	16,361
Costs Capitalized Subsequent to Acquisition	4,011
Cost amount carried at Close of Period
Land	3,126
Buildings and Equipment	20,372
Total	23,498
Accumulated Depreciation	$ (3,418)
3300 75th Avenue, Landover, MD
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 29,537
Initial Cost to Company
Land	4,110
Buildings and Equipment	36,371
Costs Capitalized Subsequent to Acquisition	3,730
Cost amount carried at Close of Period
Land	4,110
Buildings and Equipment	40,101
Total	44,211
Accumulated Depreciation	$ (13,789)
Redland 520/530, Rockville, MD
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 12,714
Buildings and Equipment	61,377
Costs Capitalized Subsequent to Acquisition	8,002
Cost amount carried at Close of Period
Land	12,714
Buildings and Equipment	69,379
Total	82,093
Accumulated Depreciation	$ (11,313)
Redland 540, Rockville, MD
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 10,740
Buildings and Equipment	17,714
Costs Capitalized Subsequent to Acquisition	6,108
Cost amount carried at Close of Period
Land	10,740
Buildings and Equipment	23,822
Total	34,562
Accumulated Depreciation	$ (5,344)
3550 Green Court, Ann Arbor, MI
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 3,630
Buildings and Equipment	4,857
Costs Capitalized Subsequent to Acquisition	0
Cost amount carried at Close of Period
Land	3,630
Buildings and Equipment	4,857
Total	8,487
Accumulated Depreciation	$ (714)
11411 E. Jefferson Avenue, Detroit, MI
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 630
Buildings and Equipment	18,002
Costs Capitalized Subsequent to Acquisition	586
Cost amount carried at Close of Period
Land	630
Buildings and Equipment	18,588
Total	19,218
Accumulated Depreciation	$ (6,322)
Rosedale Corporate Plaza, Roseville, MN
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 672
Buildings and Equipment	6,045
Costs Capitalized Subsequent to Acquisition	819
Cost amount carried at Close of Period
Land	672
Buildings and Equipment	6,864
Total	7,536
Accumulated Depreciation	$ (3,917)
1300 Summit Street, Kansas City, MO
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,776
Buildings and Equipment	12,070
Costs Capitalized Subsequent to Acquisition	925
Cost amount carried at Close of Period
Land	2,776
Buildings and Equipment	12,995
Total	15,771
Accumulated Depreciation	$ (3,690)
2555 Grand Boulevard, Kansas City, MO
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,209
Buildings and Equipment	51,522
Costs Capitalized Subsequent to Acquisition	5,414
Cost amount carried at Close of Period
Land	4,209
Buildings and Equipment	56,936
Total	61,145
Accumulated Depreciation	$ (8,213)
4241 NE 34th Street, Kansas City, MO
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,133
Buildings and Equipment	5,649
Costs Capitalized Subsequent to Acquisition	5,056
Cost amount carried at Close of Period
Land	1,470
Buildings and Equipment	10,368
Total	11,838
Accumulated Depreciation	$ (5,455)
1220 Echelon Parkway, Jackson, MS
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 14,510
Initial Cost to Company
Land	440
Buildings and Equipment	25,458
Costs Capitalized Subsequent to Acquisition	1,571
Cost amount carried at Close of Period
Land	440
Buildings and Equipment	27,029
Total	27,469
Accumulated Depreciation	$ (7,500)
2300 and 2400 Yorkmont Road, Charlotte, NC
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 1,334
Buildings and Equipment	19,075
Costs Capitalized Subsequent to Acquisition	4,222
Cost amount carried at Close of Period
Land	1,334
Buildings and Equipment	23,297
Total	24,631
Accumulated Depreciation	$ (3,549)
18010 and 18020 Burt Street, Omaha, NE
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 6,977
Buildings and Equipment	12,500
Costs Capitalized Subsequent to Acquisition	2,369
Cost amount carried at Close of Period
Land	6,977
Buildings and Equipment	14,869
Total	21,846
Accumulated Depreciation	$ (1,733)
500 Charles Ewing Boulevard, Ewing, NJ
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 42,279
Initial Cost to Company
Land	4,808
Buildings and Equipment	26,002
Costs Capitalized Subsequent to Acquisition	1,554
Cost amount carried at Close of Period
Land	4,808
Buildings and Equipment	27,556
Total	32,364
Accumulated Depreciation	$ (3,737)
299 Jefferson Road, Parsippany, NJ
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,543
Buildings and Equipment	2,914
Costs Capitalized Subsequent to Acquisition	1,282
Cost amount carried at Close of Period
Land	4,543
Buildings and Equipment	4,196
Total	8,739
Accumulated Depreciation	$ (723)
One Jefferson Road, Parsippany, NJ
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,415
Buildings and Equipment	5,249
Costs Capitalized Subsequent to Acquisition	103
Cost amount carried at Close of Period
Land	4,415
Buildings and Equipment	5,352
Total	9,767
Accumulated Depreciation	$ (741)
Airline Corporate Center, Colonie, NY
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 790
Buildings and Equipment	6,400
Costs Capitalized Subsequent to Acquisition	1,876
Cost amount carried at Close of Period
Land	790
Buildings and Equipment	8,276
Total	9,066
Accumulated Depreciation	$ (2,239)
1212 Pittsford - Victor Road, Pittsford, NY
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 608
Buildings and Equipment	78
Costs Capitalized Subsequent to Acquisition	1,627
Cost amount carried at Close of Period
Land	608
Buildings and Equipment	1,705
Total	2,313
Accumulated Depreciation	$ (174)
2231 Schrock Road, Columbus, OH
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 716
Buildings and Equipment	217
Costs Capitalized Subsequent to Acquisition	578
Cost amount carried at Close of Period
Land	716
Buildings and Equipment	795
Total	1,511
Accumulated Depreciation	$ (163)
8800 Tinicum Boulevard, Philadelphia, PA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,573
Buildings and Equipment	22,686
Costs Capitalized Subsequent to Acquisition	6,022
Cost amount carried at Close of Period
Land	5,573
Buildings and Equipment	28,708
Total	34,281
Accumulated Depreciation	$ (3,658)
446 Wrenplace Road, Fort Mill, SC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,031
Buildings and Equipment	22,524
Costs Capitalized Subsequent to Acquisition	43
Cost amount carried at Close of Period
Land	5,031
Buildings and Equipment	22,567
Total	27,598
Accumulated Depreciation	$ (1,704)
9680 Old Bailes Road, Fort Mill, SC
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 834
Buildings and Equipment	2,944
Costs Capitalized Subsequent to Acquisition	91
Cost amount carried at Close of Period
Land	834
Buildings and Equipment	3,035
Total	3,869
Accumulated Depreciation	$ (423)
16001 North Dallas Parkway, Addison, TX
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 10,282
Buildings and Equipment	63,071
Costs Capitalized Subsequent to Acquisition	2,558
Cost amount carried at Close of Period
Land	10,282
Buildings and Equipment	65,629
Total	75,911
Accumulated Depreciation	$ (9,485)
Research Park, Austin, TX
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 4,258
Buildings and Equipment	13,747
Costs Capitalized Subsequent to Acquisition	534
Cost amount carried at Close of Period
Land	4,258
Buildings and Equipment	14,281
Total	18,539
Accumulated Depreciation	$ (3,403)
10451 Clay Road, Houston, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,495
Buildings and Equipment	10,253
Costs Capitalized Subsequent to Acquisition	2,432
Cost amount carried at Close of Period
Land	5,495
Buildings and Equipment	12,685
Total	18,180
Accumulated Depreciation	$ (1,809)
202 North Castlegory Road, Houston, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 863
Buildings and Equipment	5,024
Costs Capitalized Subsequent to Acquisition	41
Cost amount carried at Close of Period
Land	863
Buildings and Equipment	5,065
Total	5,928
Accumulated Depreciation	$ (657)
4221 W. John Carpenter Freeway, Irving, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,413
Buildings and Equipment	2,365
Costs Capitalized Subsequent to Acquisition	1,843
Cost amount carried at Close of Period
Land	1,413
Buildings and Equipment	4,208
Total	5,621
Accumulated Depreciation	$ (1,445)
8675, 8701-8711 Freeport Pkwy and 8901 Esters Boulevard, Irving, TX
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 12,970
Buildings and Equipment	31,566
Costs Capitalized Subsequent to Acquisition	138
Cost amount carried at Close of Period
Land	12,970
Buildings and Equipment	31,704
Total	44,674
Accumulated Depreciation	$ (4,375)
1511 East Common Street, New Braunfels, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,965
Buildings and Equipment	1,266
Costs Capitalized Subsequent to Acquisition	251
Cost amount carried at Close of Period
Land	4,965
Buildings and Equipment	1,517
Total	6,482
Accumulated Depreciation	$ (323)
2900 West Plano Parkway, Plano, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 6,819
Buildings and Equipment	8,831
Costs Capitalized Subsequent to Acquisition	0
Cost amount carried at Close of Period
Land	6,819
Buildings and Equipment	8,831
Total	15,650
Accumulated Depreciation	$ (1,224)
3400 West Plano Parkway, Plano, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,543
Buildings and Equipment	15,964
Costs Capitalized Subsequent to Acquisition	321
Cost amount carried at Close of Period
Land	4,543
Buildings and Equipment	16,285
Total	20,828
Accumulated Depreciation	$ (2,286)
3600 Weismann Boulevard, San Antonio, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 3,493
Buildings and Equipment	6,662
Costs Capitalized Subsequent to Acquisition	2,134
Cost amount carried at Close of Period
Land	3,493
Buildings and Equipment	8,796
Total	12,289
Accumulated Depreciation	$ (1,059)
701 Clay Road, Waco, TX
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 25,903
Initial Cost to Company
Land	2,030
Buildings and Equipment	8,708
Costs Capitalized Subsequent to Acquisition	14,651
Cost amount carried at Close of Period
Land	2,060
Buildings and Equipment	23,329
Total	25,389
Accumulated Depreciation	$ (9,787)
1800 Novell Place, Provo, UT
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 7,487
Buildings and Equipment	43,487
Costs Capitalized Subsequent to Acquisition	13,364
Cost amount carried at Close of Period
Land	7,487
Buildings and Equipment	56,851
Total	64,338
Accumulated Depreciation	$ (7,307)
4885-4931 North 300 West, Provo, UT
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 3,915
Buildings and Equipment	9,429
Costs Capitalized Subsequent to Acquisition	21
Cost amount carried at Close of Period
Land	3,915
Buildings and Equipment	9,450
Total	13,365
Accumulated Depreciation	$ (1,392)
14660, 14672 and 14668 Lee Road, Chantilly, VA
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 6,966
Buildings and Equipment	74,214
Costs Capitalized Subsequent to Acquisition	17,518
Cost amount carried at Close of Period
Land	6,966
Buildings and Equipment	91,732
Total	98,698
Accumulated Depreciation	$ (15,123)
Enterchange At Meadowville, Chester, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,478
Buildings and Equipment	9,594
Costs Capitalized Subsequent to Acquisition	1,369
Cost amount carried at Close of Period
Land	1,478
Buildings and Equipment	10,963
Total	12,441
Accumulated Depreciation	$ (2,720)
7987 Ashton Avenue, Manassas, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,562
Buildings and Equipment	8,253
Costs Capitalized Subsequent to Acquisition	1,069
Cost amount carried at Close of Period
Land	1,562
Buildings and Equipment	9,322
Total	10,884
Accumulated Depreciation	$ (1,946)
Two Commercial Place, Norfolk, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,494
Buildings and Equipment	21,508
Costs Capitalized Subsequent to Acquisition	1,033
Cost amount carried at Close of Period
Land	4,494
Buildings and Equipment	22,541
Total	27,035
Accumulated Depreciation	$ (2,976)
1759 Business Center Drive, Reston, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,033
Buildings and Equipment	28,517
Costs Capitalized Subsequent to Acquisition	2,517
Cost amount carried at Close of Period
Land	4,033
Buildings and Equipment	31,034
Total	35,067
Accumulated Depreciation	$ (7,563)
1760 Business Center Drive, Reston, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 5,033
Buildings and Equipment	50,141
Costs Capitalized Subsequent to Acquisition	6,320
Cost amount carried at Close of Period
Land	5,033
Buildings and Equipment	56,461
Total	61,494
Accumulated Depreciation	$ (13,571)
1775 Wiehle Avenue, Reston, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 4,138
Buildings and Equipment	26,120
Costs Capitalized Subsequent to Acquisition	5,716
Cost amount carried at Close of Period
Land	4,138
Buildings and Equipment	31,836
Total	35,974
Accumulated Depreciation	$ (5,376)
9201 Forest Hill Avenue, Richmond, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,344
Buildings and Equipment	375
Costs Capitalized Subsequent to Acquisition	668
Cost amount carried at Close of Period
Land	1,344
Buildings and Equipment	1,043
Total	2,387
Accumulated Depreciation	$ (239)
9960 Mayland Drive, Richmond, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,614
Buildings and Equipment	15,930
Costs Capitalized Subsequent to Acquisition	4,690
Cost amount carried at Close of Period
Land	2,614
Buildings and Equipment	20,620
Total	23,234
Accumulated Depreciation	$ (5,109)
1751 Blue Hills Drive, Roanoke, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 2,689
Buildings and Equipment	7,761
Costs Capitalized Subsequent to Acquisition	0
Cost amount carried at Close of Period
Land	2,689
Buildings and Equipment	7,761
Total	10,450
Accumulated Depreciation	$ (1,076)
Atlantic Corporate Park, Sterling, VA
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 5,752
Buildings and Equipment	29,316
Costs Capitalized Subsequent to Acquisition	3,616
Cost amount carried at Close of Period
Land	5,752
Buildings and Equipment	32,932
Total	38,684
Accumulated Depreciation	$ (5,532)
Orbital Sciences Campus, Sterling, VA
Real estate and accumulated depreciation
Number of Properties | property	3
Initial Cost to Company
Land	$ 12,275
Buildings and Equipment	19,320
Costs Capitalized Subsequent to Acquisition	7,400
Cost amount carried at Close of Period
Land	12,269
Buildings and Equipment	26,726
Total	38,995
Accumulated Depreciation	$ (3,205)
Sterling Park Business Center, Sterling, VA
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 25,934
Initial Cost to Company
Land	5,871
Buildings and Equipment	44,324
Costs Capitalized Subsequent to Acquisition	127
Cost amount carried at Close of Period
Land	5,871
Buildings and Equipment	44,451
Total	50,322
Accumulated Depreciation	$ (6,951)
65 Bowdoin Street, S. Burlington VT
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 700
Buildings and Equipment	8,416
Costs Capitalized Subsequent to Acquisition	148
Cost amount carried at Close of Period
Land	700
Buildings and Equipment	8,564
Total	9,264
Accumulated Depreciation	$ (2,959)
Stevens Center, Richland, WA
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 3,970
Buildings and Equipment	17,035
Costs Capitalized Subsequent to Acquisition	4,776
Cost amount carried at Close of Period
Land	4,042
Buildings and Equipment	21,739
Total	25,781
Accumulated Depreciation	$ (13,025)
Unison Elliott Bay-Lab Space, Seattle, WA
Real estate and accumulated depreciation
Number of Properties | property	2
Initial Cost to Company
Land	$ 17,316
Buildings and Equipment	34,281
Costs Capitalized Subsequent to Acquisition	137,343
Cost amount carried at Close of Period
Land	17,316
Buildings and Equipment	171,624
Total	188,940
Accumulated Depreciation	$ (5,302)
Unison Elliott Bay-Office Space, Seattle, WA
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 9,324
Buildings and Equipment	18,459
Costs Capitalized Subsequent to Acquisition	5,101
Cost amount carried at Close of Period
Land	9,324
Buildings and Equipment	23,560
Total	32,884
Accumulated Depreciation	$ (2,953)
5353 Yellowstone Road, Cheyenne, WY
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 1,915
Buildings and Equipment	8,217
Costs Capitalized Subsequent to Acquisition	2,402
Cost amount carried at Close of Period
Land	1,950
Buildings and Equipment	10,584
Total	12,534
Accumulated Depreciation	$ (6,251)
Properties Held for Sale
Real estate and accumulated depreciation
Number of Properties | property	1
Encumbrances	$ 0
Initial Cost to Company
Land	19,379
Buildings and Equipment	20,115
Costs Capitalized Subsequent to Acquisition	1,136
Impairment/ Writedowns	(11,299)
Cost amount carried at Close of Period
Land	13,555
Buildings and Equipment	15,776
Total	29,331
Accumulated Depreciation	$ (3,030)
Properties Held for Sale | 400 South Jefferson Street, Chicago, IL
Real estate and accumulated depreciation
Number of Properties | property	1
Initial Cost to Company
Land	$ 19,379
Buildings and Equipment	20,115
Costs Capitalized Subsequent to Acquisition	1,136
Impairment/ Writedowns	(11,299)
Cost amount carried at Close of Period
Land	13,555
Buildings and Equipment	15,776
Total	29,331
Accumulated Depreciation	$ (3,030)
Total Real Estate Assets
Real estate and accumulated depreciation
Number of Properties | property	152
Encumbrances	$ 172,131
Initial Cost to Company
Land	805,025
Buildings and Equipment	2,512,157
Costs Capitalized Subsequent to Acquisition	793,652
Impairment/ Writedowns	(15,824)
Cost amount carried at Close of Period
Land	799,865
Buildings and Equipment	3,295,145
Total	4,095,010
Accumulated Depreciation	$ (653,209)

SCHEDULE III REAL ESTATE AND _3

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2023 USD ($) property	Jan. 31, 2024 USD ($) property
Real estate and accumulated depreciation
Mortgage debt, net	$ 5,189
Aggregate cost for federal income tax purposes	$ 7,540,917
Useful life of buildings and improvements	40 years
Useful life of equipment	7 years
Mortgage Note Payable
Real estate and accumulated depreciation
Principal balance	$ 177,320
Line of Credit | Revolving credit facility
Real estate and accumulated depreciation
Number of properties used to secured mortgage note | property	19
Line of Credit | Revolving credit facility | Subsequent Event
Real estate and accumulated depreciation
Number of properties used to secured mortgage note | property		19
Maximum borrowing capacity on revolving credit facility		$ 325,000
Line of Credit | Secured Debt
Real estate and accumulated depreciation
Number of properties used to secured mortgage note | property	19
Line of Credit | Secured Debt | Subsequent Event
Real estate and accumulated depreciation
Number of properties used to secured mortgage note | property		19
Principal balance		$ 100,000
Mortgage note payable, 7.671% interest rate, due in 2028 | Mortgage Note Payable
Real estate and accumulated depreciation
Number of properties used to secured mortgage note | property	2
Principal balance	$ 54,300

SCHEDULE III REAL ESTATE AND _4

SCHEDULE III REAL ESTATE AND ACCUMULATED DEPRECIATION - Carrying Amount and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Real Estate Properties
Balance at the beginning of the period	$ 3,936,074	$ 3,911,086	$ 3,522,143
Additions	221,246	222,951	584,805
Loss on asset impairment	(11,299)	(17,303)	(58,696)
Disposals	(51,011)	(173,841)	(72,137)
Cost basis adjustment		(4,235)	(37,239)
Reclassification of assets of properties held for sale	(29,331)	(2,584)	(27,790)
Balance at the end of the period	4,065,679	3,936,074	3,911,086
Accumulated Depreciation
Balance at the beginning of the period	561,458	495,912	451,914
Additions	107,460	96,966	92,266
Loss on asset impairment	0	0	0
Disposals	(15,709)	(26,997)	(8,675)
Cost basis adjustment		(4,235)	(37,239)
Reclassification of assets of properties held for sale	(3,030)	(188)	(2,354)
Balance at the end of the period	$ 650,179	$ 561,458	$ 495,912