COPT Defense Properties (CDP) 10-K 24 Feb 23 2022 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2022	Feb. 07, 2023	Jun. 30, 2022
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-14023
Entity Registrant Name	CORPORATE OFFICE PROPERTIES TRUST
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	23-2947217
Entity Address, Address Line One	6711 Columbia Gateway Drive
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Columbia
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	21046
City Area Code	443
Local Phone Number	285-5400
Title of 12(b) Security	Common Shares of beneficial interest, $0.01 par value
Trading Symbol	OFC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2.5
Entity Common Stock, Shares Outstanding		112,421,993
Documents Incorporated by Reference	Portions of the proxy statement of Corporate Office Properties Trust for its 2023 Annual Meeting of Shareholders to be filed within 120 days after the end of the fiscal year covered by this Form 10-K are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0000860546
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Amendment Flag	false

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2022
Audit Information [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Baltimore, Maryland
Auditor Firm ID	238

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Properties, net:
Operating properties, net	$ 3,258,899	$ 3,090,510
Projects in development or held for future development	297,499	442,434
Total properties, net	3,556,398	3,532,944
Property - operating right-of-use assets	37,020	38,361
Assets held for sale, net	161,286	192,699
Cash and cash equivalents	12,337	13,262
Investment in unconsolidated real estate joint ventures	21,460	39,889
Accounts receivable, net	43,334	40,752
Deferred rent receivable	125,147	108,926
Lease incentives, net	49,757	51,486
Deferred leasing costs (net of accumulated amortization of $35,270 and $31,768, respectively)	69,339	65,850
Intangible assets on property acquisitions, net	9,959	14,567
Prepaid expenses and other assets, net	86,617	81,490
Total assets	4,257,275	4,262,452
Liabilities:
Debt, net	2,231,794	2,272,304
Accounts payable and accrued expenses	157,998	186,202
Rents received in advance and security deposits	30,016	32,262
Dividends and distributions payable	31,400	31,299
Deferred revenue associated with operating leases	11,004	9,341
Property - operating lease liabilities	28,759	29,342
Other liabilities	18,556	17,729
Total liabilities	2,509,527	2,578,479
Commitments and contingencies (Note 19)
Redeemable noncontrolling interests	26,293	26,898
Shareholders’ equity:
Common Shares of beneficial interest ($0.01 par value; 150,000,000 shares authorized; shares issued and outstanding of 112,423,893 at December 31, 2022 and 112,327,533 at December 31, 2021)	1,124	1,123
Additional paid-in capital	2,486,116	2,481,539
Cumulative distributions in excess of net income	(807,508)	(856,863)
Accumulated other comprehensive income (loss)	2,071	(3,059)
Total shareholders’ equity	1,681,803	1,622,740
Noncontrolling interests in subsidiaries:
Common units in Corporate Office Properties, L.P. (“COPLP”)	25,808	21,363
Other consolidated entities	13,844	12,972
Noncontrolling interests in subsidiaries	39,652	34,335
Total equity	1,721,455	1,657,075
Total liabilities, redeemable noncontrolling interests and equity	4,257,275	4,262,452
Investing Receivables
Properties, net:
Investing receivables (net of allowance for credit losses of $2,794 and $1,599, respectively)	$ 84,621	$ 82,226

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accumulated amortization of deferred leasing costs	$ 35,270	$ 31,768
Common Shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Common Shares of beneficial interest, shares authorized (in shares)	150,000,000	150,000,000
Common Shares of beneficial interest, shares issued (in shares)	112,423,893	112,327,533
Common Shares of beneficial interest, shares outstanding (in shares)	112,423,893	112,327,533
Investing Receivables
Investing receivable allowance for credit loss	$ 2,794	$ 1,599

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenues
Lease revenue		$ 580,169	$ 553,668	$ 509,114
Other property revenue		4,229	2,902	2,600
Construction contract and other service revenues		154,632	107,876	70,640
Total revenues		739,030	664,446	582,354
Operating expenses
Property operating expenses		227,430	213,377	190,796
Depreciation and amortization associated with real estate operations		141,230	137,543	126,503
Construction contract and other service expenses		149,963	104,053	67,615
General, administrative and leasing expenses		35,798	36,127	33,001
Business development expenses and land carry costs		3,193	4,647	4,473
Impairment losses		0	0	1,530
Total operating expenses		557,614	495,747	423,918
Interest expense		(61,174)	(65,398)	(67,937)
Interest and other income		9,341	7,879	8,574
Credit loss (expense) recoveries		(271)	1,128	933
Gain on sales of real estate		19,250	65,590	30,209
Gain on sale of investment in unconsolidated real estate joint venture		0	0	29,416
Loss on early extinguishment of debt		(609)	(100,626)	(7,306)
Loss on interest rate derivatives		0	0	(53,196)
Income from continuing operations before equity in income of unconsolidated entities and income taxes		147,953	77,272	99,129
Equity in income of unconsolidated entities		1,743	1,093	1,825
Income tax expense		(447)	(145)	(353)
Income from continuing operations		149,249	78,220	100,601
Discontinued operations		29,573	3,358	2,277
Net income		178,822	81,578	102,878
Net income attributable to noncontrolling interests:
Common units in COPLP		(2,603)	(1,012)	(1,180)
Preferred units in COPLP		0	0	(300)
Other consolidated entities		(3,190)	(4,025)	(4,024)
Net income attributable to COPT common shareholders		$ 173,029	$ 76,541	$ 97,374
Basic EPS:
Income from continuing operations - basic (in dollars per share)	[1]	$ 1.28	$ 0.65	$ 0.85
Discontinued operations - basic (in dollars per share)	[1]	0.26	0.03	0.02
Net income attributable to COPT common shareholders - basic (in dollars per share)	[1]	1.54	0.68	0.87
Diluted EPS:
Income from continuing operations - diluted (in dollars per share)	[1]	1.27	0.65	0.85
Discontinued operations - diluted (in dollar per share)	[1]	0.26	0.03	0.02
Net income attributable to COPT common shareholders - diluted (in dollars per share)	[1]	$ 1.53	$ 0.68	$ 0.87
[1]Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 178,822	$ 81,578	$ 102,878
Other comprehensive income
Unrealized income (loss) on interest rate derivatives	4,730	1,379	(39,454)
Reclassification adjustments on interest rate derivatives recognized in interest expense	996	5,048	3,725
Reclassification adjustments on interest rate derivatives recognized in loss on interest rate derivatives	0	0	51,865
Total other comprehensive income	5,726	6,427	16,136
Comprehensive income	184,548	88,005	119,014
Comprehensive income attributable to noncontrolling interests	(6,389)	(5,366)	(5,353)
Comprehensive income attributable to COPT	$ 178,159	$ 82,639	$ 113,661

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Shares	Common Shares Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in Capital	Additional Paid-in Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Cumulative Distributions in Excess of Net Income	Cumulative Distributions in Excess of Net Income Cumulative Effect, Period of Adoption, Adjustment	Cumulative Distributions in Excess of Net Income Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss) Income Cumulative Effect, Period of Adoption, Adjusted Balance	Noncontrolling Interests	Noncontrolling Interests Cumulative Effect, Period of Adoption, Adjusted Balance
Balance at Dec. 31, 2019	$ 1,719,245	$ (5,541)	$ 1,713,704	$ 1,121	$ 1,121	$ 2,481,558	$ 2,481,558	$ (778,275)	$ (5,541)	$ (783,816)	$ (25,444)	$ 0	$ (25,444)	$ 40,285	$ 40,285
Increase (Decrease) in Shareholders' Equity
Conversion of common units to common shares	0			0		211								(211)
Redemption of preferred units	(8,800)													(8,800)
Share-based compensation issuance, net of redemptions	6,584			1		4,676								1,907
Redemption of vested equity awards	(1,699)					(1,699)
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP	0					767								(767)
Comprehensive income	115,588							97,374			16,287			1,927
Dividends	(123,394)							(123,394)
Distributions to owners of common and preferred units in COPLP	(1,746)													(1,746)
Contributions from noncontrolling interests in other consolidated entities	112													112
Distributions to noncontrolling interests in other consolidated entities	(30)													(30)
Adjustment to arrive at fair value of redeemable noncontrolling interests	(6,607)					(6,607)
Balance at Dec. 31, 2020	1,693,712			1,122		2,478,906		(809,836)			(9,157)			32,677
Increase (Decrease) in Shareholders' Equity
Conversion of common units to common shares	0			0		121								(121)
Redemption of common units	(339)													(339)
Share-based compensation issuance, net of redemptions	8,481			1		4,301								4,179
Redemption of vested equity awards	(2,492)					(2,492)
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP	0					2,318								(2,318)
Comprehensive income	84,845							76,541			6,098			2,206
Dividends	(123,568)							(123,568)
Distributions to owners of common and preferred units in COPLP	(1,595)													(1,595)
Distributions to noncontrolling interests in other consolidated entities	(30)													(30)
Adjustment to arrive at fair value of redeemable noncontrolling interests	(1,615)					(1,615)
Other	(324)													(324)
Balance at Dec. 31, 2021	1,657,075			1,123		2,481,539		(856,863)			(3,059)			34,335
Increase (Decrease) in Shareholders' Equity
Redemption of common units	(513)													(513)
Share-based compensation issuance, net of redemptions	9,534			1		4,098								5,435
Redemption of vested equity awards	(1,230)					(1,230)
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP	0					1,273								(1,273)
Comprehensive income	181,741							173,029			5,130			3,582
Dividends	(123,674)							(123,674)
Distributions to owners of common and preferred units in COPLP	(1,883)													(1,883)
Distributions to noncontrolling interests in other consolidated entities	(31)													(31)
Adjustment to arrive at fair value of redeemable noncontrolling interests	436					436
Balance at Dec. 31, 2022	$ 1,721,455			$ 1,124		$ 2,486,116		$ (807,508)			$ 2,071			$ 39,652

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Stockholders' Equity [Abstract]
Common Shares of beneficial interest, shares outstanding (in shares)	112,423,893	112,327,533	112,181,759
Conversion of common units to common shares (in shares)	0	8,054	14,009
Share-based compensation issuance, net of redemptions (in shares)	96,360	137,720	99,045

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Revenues from real estate operations received	$ 581,139	$ 571,092	$ 542,727
Construction contract and other service revenues received	155,108	100,222	78,470
Property operating expenses paid	(231,422)	(223,254)	(202,660)
Construction contract and other service expenses paid	(160,497)	(86,602)	(67,760)
General, administrative, leasing, business development and land carry costs paid	(32,852)	(29,072)	(31,406)
Interest expense paid	(56,061)	(65,184)	(61,471)
Interest and other income received	19,327	1,099	1,369
Lease incentives paid	(10,374)	(18,127)	(11,925)
Sales-type lease costs paid	0	(2,065)	(10,747)
Income taxes paid	0	(60)	(4)
Other	1,457	1,099	1,831
Net cash provided by operating activities	265,825	249,148	238,424
Cash flows from investing activities
Development and redevelopment of properties	(283,147)	(267,905)	(344,401)
Tenant improvements on operating properties	(43,606)	(21,488)	(28,754)
Other capital improvements on operating properties	(36,377)	(30,026)	(32,756)
Proceeds from sale of properties	281,071	143,116	83,165
Proceeds from sale of investment in unconsolidated real estate joint venture	0	0	59,841
Non-operating distributions from unconsolidated real estate joint venture	26,627	1,287	3,695
Investing receivables funded	(19,712)	(5,880)	(272)
Investing receivables payments received	6,000	0	8,000
Leasing costs paid	(13,591)	(21,913)	(16,938)
Settlement of interest rate derivatives	(625)	0	(53,130)
Other	(97)	(160)	(4,242)
Net cash used in investing activities	(83,457)	(202,969)	(325,792)
Proceeds from debt
Revolving Credit Facility	852,000	597,000	664,000
Unsecured senior notes	0	1,382,614	395,264
Term loan facilities	125,000	0	150,000
Other debt proceeds	0	4,630	56,931
Repayments of debt
Revolving Credit Facility	(717,000)	(664,000)	(698,000)
Unsecured senior notes	0	(900,000)	(300,000)
Term loan facilities	(300,000)	(100,000)	0
Scheduled principal amortization	(3,333)	(3,860)	(4,125)
Other debt repayments	0	(138,397)	(12,031)
Deferred financing costs paid	(6,506)	(3,620)	(2,400)
Payments in connection with early extinguishment of debt	(6)	(95,180)	(7,029)
Common share dividends paid	(123,645)	(123,527)	(123,367)
Distributions paid to redeemable noncontrolling interests	(3,396)	(2,273)	(14,357)
Redemption of preferred units	0	0	(8,800)
Other	(6,289)	(4,283)	(4,815)
Net cash (used in) provided by financing activities	(183,175)	(50,896)	91,271
Net (decrease) increase in cash and cash equivalents and restricted cash	(807)	(4,717)	3,903
Cash and cash equivalents and restricted cash
Beginning of year	17,316	22,033	18,130
End of year	16,509	17,316	22,033
Reconciliation of net income to net cash provided by operating activities:
Net income	178,822	81,578	102,878
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and other amortization	143,593	150,644	140,031
Impairment losses	0	0	1,530
Amortization of deferred financing costs and net debt discounts	4,737	5,224	4,272
Increase in deferred rent receivable	(19,288)	(19,090)	(2,168)
Gain on sales of real estate	(47,814)	(65,590)	(30,209)
Gain on sale of investment in unconsolidated real estate joint venture	0	0	(29,416)
Share-based compensation	8,789	7,979	6,503
Loss on early extinguishment of debt	609	100,626	7,306
Loss on interest rate derivatives	0	0	53,196
Other	10,073	(5,047)	(7,855)
Changes in operating assets and liabilities:
Increase in accounts receivable	(2,436)	(662)	(6,377)
Decrease (increase) in lease incentives and prepaid expenses and other assets, net	2,130	(27,355)	(7,626)
(Decrease) increase in accounts payable, accrued expenses and other liabilities	(11,144)	22,004	6,554
Decrease in rents received in advance and security deposits	(2,246)	(1,163)	(195)
Net cash provided by operating activities	265,825	249,148	238,424
Reconciliation of cash and cash equivalents and restricted cash:
Cash and cash equivalents	12,337	13,262	18,369
Restricted cash	4,172	4,054	3,664
Cash and cash equivalents and restricted cash	16,509	17,316	22,033
Supplemental schedule of non-cash investing and financing activities:
(Decrease) increase in accrued capital improvements, leasing and other investing activity costs	(11,453)	20,667	(9,421)
Reclassification of finance right-of-use asset to operating properties, net in connection with exercise of bargain purchase option	0	37,831	0
Recognition of operating right-of-use assets and related lease liabilities	683	328	13,340
Investment in unconsolidated real estate joint ventures retained in property disposition	6,738	11,842	11,474
Increase (decrease) in fair value of derivatives applied to accumulated other comprehensive income and noncontrolling interests	5,236	6,233	(35,728)
Dividends/distributions payable	31,400	31,299	31,231
Decrease in noncontrolling interests and increase in shareholders’ equity in connection with the conversion of common units into common shares	0	121	211
Adjustments to noncontrolling interests resulting from changes in COPLP ownership	(1,273)	(2,318)	(767)
(Decrease) increase in redeemable noncontrolling interests and (increase) decrease in equity to carry redeemable noncontrolling interests at fair value	$ (436)	$ 1,615	$ 6,607

Organization

Organization	12 Months Ended
	Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Corporate Office Properties Trust (“COPT”) and subsidiaries (collectively, the “Company”, “we” or “us”) is a fully-integrated and self-managed real estate investment trust (“REIT”). We own, manage, lease, develop and selectively acquire office and data center properties. The majority of our portfolio is in locations that support the United States Government (“USG”) and its contractors, most of whom are engaged in national security, defense and information technology (“IT”) related activities servicing what we believe are growing, durable, priority missions (“Defense/IT Locations”). We also own a portfolio of office properties located in select urban submarkets in the Greater Washington, DC/Baltimore region with durable Class-A office fundamentals and characteristics (“Regional Office”). As of December 31, 2022, our properties included the following (all references to number of properties, square footage and acres are unaudited): • 194 properties totaling 23.0 million square feet comprised of 17.7 million square feet in 166 office properties and 5.3 million square feet in 28 single-tenant data center shells. We owned 21 of these data center shells through unconsolidated real estate joint ventures; • seven properties under development (five office properties and two data center shells), including two partially-operational properties, that we estimate will total approximately 1.0 million square feet upon completion; and • approximately 710 acres of land controlled for future development that we believe could be developed into approximately 9.5 million square feet and 43 acres of other land. We conduct almost all of our operations and own almost all of our assets through our operating partnership, Corporate Office Properties, L.P. (“COPLP”) and subsidiaries (collectively, the “Operating Partnership”), of which COPT is the sole general partner. COPLP owns real estate directly and through subsidiary partnerships and limited liability companies (“LLCs”). In addition to owning real estate, COPLP also owns subsidiaries that provide real estate services such as property management, development and construction services primarily for our properties but also for third parties. Some of these services are performed by a taxable REIT subsidiary (“TRS”). Equity interests in COPLP are in the form of common and preferred units. As of December 31, 2022, COPT owned 98.0% of the outstanding COPLP common units (“common units”) and there were no preferred units outstanding. Common units not owned by COPT carry certain redemption rights. The number of common units owned by COPT is equivalent to the number of outstanding common shares of beneficial interest (“common shares”) of COPT, and the entitlement of common units to quarterly distributions and payments in liquidation is substantially the same as that of COPT common shareholders.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation These consolidated financial statements include the accounts of COPT, the Operating Partnership, their subsidiaries and other entities in which COPT has a majority voting interest and control. We also consolidate certain entities when control of such entities can be achieved through means other than voting rights (“variable interest entities” or “VIEs”) if we are deemed to be the primary beneficiary of such entities. We eliminate all intercompany balances and transactions in consolidation. We use the equity method of accounting when we own an interest in an entity and can exert significant influence over but cannot control the entity’s operations. We discontinue equity method accounting if our investment in an entity (and net advances) is reduced to zero unless we have guaranteed obligations of the entity or are otherwise committed to provide further financial support for the entity. When we own an equity investment in an entity and cannot exert significant influence over its operations, we measure the investment at fair value, with changes recognized through net income. For an investment without a readily determinable fair value, we measure the investment at cost, less any impairments, plus or minus changes resulting from observable price changes for an identical or similar investment of the same issuer. Reclassifications We reclassified certain amounts from prior periods to conform to the current period presentation of our consolidated financial statements with no effect on previously reported net income or equity. Use of Estimates in the Preparation of Financial Statements We make estimates and assumptions when preparing financial statements under generally accepted accounting principles (“GAAP”). These estimates and assumptions affect various matters, including: • the reported amounts of assets and liabilities in our consolidated balance sheets as of the dates of the financial statements; • the disclosure of contingent assets and liabilities as of the dates of the financial statements; and • the reported amounts of revenues and expenses in our consolidated statements of operations during the reporting periods. Significant estimates are inherent in the presentation of our financial statements in a number of areas, including the evaluation of the collectability of accounts and deferred rent receivable, the determination of estimated useful lives of assets, the determination of lease terms, the evaluation of long-lived assets for impairment, the amount of impairment losses recognized, the allocation of property acquisition costs, the amount of revenue recognized relating to tenant improvements, the level of expense recognized in connection with share-based compensation and the determination of accounting method for investments. Actual results could differ from these and other estimates. Properties We report properties to be developed or held and used in operations at our depreciated cost, reduced for impairment losses. We capitalize direct and indirect project costs (including related compensation and other indirect costs), interest expense and real estate taxes associated with properties, or portions thereof, undergoing development or redevelopment activities. In capitalizing interest expense, if there is a specific borrowing for a property undergoing development or redevelopment activities, we apply the interest rate of that borrowing to the average accumulated expenditures that do not exceed such borrowing; for the portion of expenditures exceeding any such specific borrowing, we apply our weighted average interest rate on other borrowings to the expenditures. We continue to capitalize costs while development or redevelopment activities are underway until a property becomes “operational,” which occurs when lease terms commence (generally when the tenant has control of the leased space and we have delivered the premises to the tenant as required under the terms of such lease), but no later than one year after the cessation of major construction activities. When leases commence on portions of a newly-developed or redeveloped property in the period prior to one year from the cessation of major construction activities, we consider that property to be “partially operational.” When a property is partially operational, we allocate the costs associated with the property between the portion that is operational and the portion under development. We start depreciating costs associated with newly-developed or redeveloped properties as they become operational. For newly-developed properties, we classify improvements provided under the terms of a lease that are deemed to be landlord assets (as discussed further below) as new building development costs. Most of our leases provide for some form of improvements to leased space. When we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets. If the improvements are landlord assets, we capitalize the cost of the improvements and recognize depreciation expense over the estimated useful lives of the assets as discussed below. We recognize any payments from the tenant for such assets as lease revenue over the term of the lease. If the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset and amortize it as a reduction of rental revenue over the term of the lease. In determining whether improvements constitute landlord or tenant assets, we consider numerous factors, including whether the economic substance of the lease terms is properly reflected and whether the improvements: have value to us as real estate; are unique to the tenant or reusable by other tenants; may be altered or removed by the tenant without our consent or without compensating us for any lost fair value; or are owned, and remain, with us or the tenant at the end of the lease term. We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years We report properties disposed or classified as held for sale as discontinued operations when the disposition represents a strategic shift having a major effect on our operations and financial results (such as a disposition of a reportable segment or subsegment or major line of business). For discontinued operations, we classify for all periods presented the associated: assets as held for sale on our consolidated balance sheets; and results of operations as discontinued operations on our consolidated statements of operations (including interest expense on debt specifically identifiable to such components). For periods in which a property not reported as discontinued operations is classified as held for sale, we classify the assets of the property’s asset group as held for sale on our consolidated balance sheets. Sales of Properties We recognize gains from sales of consolidated interests in properties when we transfer control of such interests. Impairment of Properties We assess the asset groups associated with each of our properties, including operating properties, properties in development, land held for future development, related intangible assets, right-of-use assets, deferred rents receivable and lease liabilities, for indicators of impairment quarterly or when circumstances indicate that an asset group may be impaired. If our analyses indicate that the carrying values of certain properties’ asset groups may be impaired, we perform a recovery analysis for such asset groups. For properties to be held and used, we analyze recoverability based on the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over, in most cases, a ten-year holding period. If we believe it is more likely than not that we will dispose of the properties earlier, we analyze recoverability using a probability weighted analysis of the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over the various possible holding periods. If the analysis indicates that the carrying value of a tested property’s asset group is not recoverable from its estimated future cash flows, the property’s asset group is written down to the property’s estimated fair value and an impairment loss is recognized. If and when our plans change, we revise our recoverability analyses to use the cash flows expected from the operations and eventual disposition of such property using holding periods that are consistent with our revised plans; as a result, changes in holding periods may require us to recognize impairment losses. Fair values are estimated based on contract prices, indicative bids, discounted cash flow analyses, yield analyses or comparable sales analyses. Estimated cash flows used in our impairment analyses are based on our plans for the property and our views of market and economic conditions. The estimates consider items such as current and future market rental and occupancy rates, estimated operating and capital expenditures and recent sales data for comparable properties; most of these items are influenced by market data obtained from real estate leasing and brokerage firms and our direct experience with the properties and their markets. When we determine that a property is held for sale, we stop depreciating the property and estimate the property’s fair value, net of selling costs; if we then determine that the estimated fair value, net of selling costs, is less than the net carrying value of the property’s asset group, we recognize an impairment loss equal to the difference and reduce the net carrying value of the property’s asset group. Acquisition of Operating Properties Upon completion of operating property acquisitions, we allocate the purchase price to tangible and intangible assets and liabilities associated with such acquisitions based on our estimates of their fair values. We determine these fair values by using market data and independent appraisals available to us and making numerous estimates and assumptions. We allocate operating property acquisitions to the following components: • properties based on a valuation performed under the assumption that the property is vacant upon acquisition (the “if-vacant value”). The if-vacant value is allocated based on the valuation performed between land and buildings or, in the case of properties under development, development in progress. We also allocate additional amounts to properties for in-place tenant improvements based on our estimate of improvements per square foot provided under market leases that would be attributable to the remaining non-cancelable terms of the respective leases; • above- and below-market lease intangible assets or liabilities based on the present value (using an estimated interest rate reflective of the risks associated with the leases acquired) of the difference between: (1) the contractual amounts to be received pursuant to the in-place leases; and (2) our estimate of fair market lease rates for the corresponding spaces, measured over a period equal to the remaining non-cancelable terms of the respective leases. The capitalized above- and below-market lease values are amortized as adjustments to lease revenue over the remaining lease terms of the respective leases, and to renewal periods in the case of below-market leases; • in-place lease value based on our estimates of: (1) the present value of additional income to be realized as a result of leases being in place on the acquired properties; and (2) costs to execute similar leases. Our estimate of costs to execute similar leases includes leasing commissions, legal and other related costs; • tenant relationship value based on our evaluation of the specific characteristics of each tenant’s lease and our overall relationship with that respective tenant. Characteristics we consider in determining these values include the nature and extent of our existing business relationships with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals, among other factors; and • above- and below-market cost arrangements (such as real estate tax treaties or above- or below-market ground leases) based on the present value of the expected benefit from any such arrangements in place on the property at the time of acquisition. Leased Assets, as a Lessee We recognize right-of-use assets and lease liabilities for land and other assets leased by us from third parties for terms of at least one year. We recognize lease expense over lease terms on a straight-line basis for operating leases and on an effective interest method basis for finance leases. In determining right-of-use assets and lease liabilities, we estimate an appropriate incremental borrowing rate on a fully-collateralized basis for the terms of the leases. Since the terms under our land leases are usually significantly longer than the terms of borrowings available to us on a fully-collateralized basis, our estimates of rates for such leases require significant judgment, and consider factors such as estimated interest rates available to us on a fully-collateralized basis for shorter-termed debt and U.S. Treasury rates. Cash and Cash Equivalents Cash and cash equivalents include all cash and liquid investments that mature three months or less from when they are purchased. Cash equivalents are reported at cost, which approximates fair value. We maintain our cash in bank accounts in amounts that may exceed federally insured limits at times. We have not experienced any losses on these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions. Investments in Marketable Securities We classify marketable securities as trading securities when we have the intent to sell such securities in the near term, and classify other marketable securities as available-for-sale securities. We determine the appropriate classification of investments in marketable securities at the acquisition date and re-evaluate the classification at each balance sheet date. We report investments in marketable securities classified as trading securities at fair value (which is included in the line entitled “Prepaid expenses and other assets, net” on our consolidated balance sheets), with unrealized gains and losses recognized through earnings; on our consolidated statements of cash flows, we classify cash flows from these securities as operating activities. Receivables and Credit Losses We write off receivables when we believe the facts and circumstances indicate that continued pursuit of collection is no longer warranted. When cash is received in connection with receivables for which we have previously recognized credit losses, we recognize reductions in our credit losses. Lease Revenue We estimate the collectability of lease revenue and related accounts receivable using judgement based on the credit status and payment history of the related tenants. If we deem that collectability of revenue under a lease is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. Financial Assets and Other Instruments Effective January 1, 2020, we adopted guidance issued by the Financial Accounting Standards Board (“FASB”) that changed how we measure credit losses for most financial assets and certain other instruments not measured at fair value through net income from an incurred loss model to an expected loss approach. We adopted this guidance using the modified retrospective transition method under which we recognized a $5.5 million allowance for credit losses by means of a cumulative-effect adjustment to cumulative distributions in excess of net income and did not adjust prior comparative reporting periods. Our items within the scope of this guidance include: • investing receivables, as disclosed in Note 8; • tenant notes receivable; • net investment in sales-type leases; • other assets comprised of non-lease revenue related accounts receivable (primarily from construction contract services) and contract assets from unbilled construction contract revenue; and • off-balance sheet credit exposures. Under this guidance, we recognize an estimate of our expected credit losses on these items as an allowance, as the guidance requires that financial assets be measured on an amortized cost basis and be presented at the net amount expected to be collected (or as a separate liability in the case of off-balance sheet credit exposures). The allowance represents the portion of the amortized cost basis that we do not expect to collect (or loss we expect to incur in the case of off-balance sheet credit exposures) due to credit over the contractual life based on available information relevant to assessing the collectability of cash flows, which includes consideration of past events, current conditions and reasonable and supportable forecasts of future economic conditions (including consideration of asset- or borrower-specific factors). The allowance for expected credit losses reflects the risk of loss, even when that risk is remote. An allowance for credit losses is measured and recorded upon the initial recognition of a financial asset (or off-balance sheet credit exposure), regardless of whether it is originated or purchased. Quarterly, the expected losses are re-estimated, considering any cash receipts and changes in risks or assumptions, with resulting adjustments recognized as credit loss expense or recoveries on our consolidated statements of operations. We estimate expected credit losses for items within the scope of this guidance using historical loss rate information developed for varying classifications of credit risk and contractual lives. Due to our limited quantity of items within the scope of this guidance and the unique risk characteristics of such items, we individually assign each in-scope item a credit risk classification. The credit risk classifications assigned by us are determined based on credit ratings assigned by ratings agencies (as available) or are internally-developed based on available financial information, historical payment experience, credit documentation, other publicly available information and current economic trends. In addition, for certain items in which the risk of credit loss is affected by the economic performance of a real estate development project, we develop probability weighted scenario analyses for varying levels of performance in estimating our credit loss allowance (applicable to our notes receivable from the City of Huntsville disclosed in Note 8 and a tax incremental financing obligation disclosed in Note 19). When we believe that collection of interest income on an investing or tenant note receivable is not probable, we place the receivable on nonaccrual status, meaning interest income is recognized when payments are received rather than on an accrual basis. Deferred Leasing Costs We defer costs incurred to obtain new tenant leases or extend existing tenant leases. We amortize these costs evenly over the lease terms. We classify leasing costs paid as an investing activity on our statements of cash flows since such costs are necessary in order for us to generate long-term future cash flows from our properties. When tenant leases are terminated early, we expense any unamortized deferred leasing costs associated with those leases over the shortened lease term. Intangible Assets and Deferred Revenue on Property Acquisitions We amortize intangible assets and deferred revenue on property acquisitions as follows: Asset Type Amortization Period Statement of Operations Location Above- and below-market leases Related lease terms Lease revenue In-place lease value Related lease terms Depreciation and amortization associated with real estate operations Tenant relationship value Estimated period of time that tenant will lease space in property Depreciation and amortization associated with real estate operations Deferred Financing Costs We defer costs of financing arrangements and recognize these costs as interest expense over the related debt terms on a straight-line basis, which approximates the amortization that would occur under the effective interest method of amortization. We expense any unamortized loan costs when loans are retired early or significantly modified. We present deferred costs of financing arrangements as a direct deduction from the related debt liability, except for costs attributable to line-of-credit arrangements and interest rate derivatives, which we present in the balance sheet in the line entitled “prepaid expenses and other assets, net”. Interest Rate Derivatives Our primary objectives in using interest rate derivatives are to add stability to interest expense and to manage exposure to interest rate movements. To accomplish this objective, we use interest rate swaps as part of our interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for our making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. We use interest rate swaps to hedge the cash flows associated with interest rates on variable-rate debt borrowings. We have also used forward-starting interest rate swaps to hedge the cash flows associated with interest rates on forecasted fixed-rate borrowings. We recognize all derivatives as assets or liabilities on our consolidated balance sheet at fair value. We defer all changes in the fair value of designated cash flow hedges to accumulated other comprehensive income (“AOCI”) or loss (“AOCL”), reclassifying such deferrals to interest expense as interest expense is recognized on the hedged forecasted transactions. When an interest rate swap designated as a cash flow hedge no longer qualifies for hedge accounting and the hedged transactions are probable not to occur, we recognize changes in the fair value of the hedge previously deferred to AOCI or AOCL, along with any changes in fair value occurring thereafter, through earnings. We do not use interest rate derivatives for trading or speculative purposes. We manage counter-party risk by only entering into contracts with major financial institutions based upon their credit ratings and other risk factors. We use standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost and termination cost in computing the fair value of derivatives at each balance sheet date. We made an accounting policy election to use an exception provided for in the applicable accounting guidance with respect to measuring counterparty credit risk for derivative instruments; this election enables us to measure the fair value of groups of assets and liabilities associated with derivative instruments consistently with how market participants would price the net risk exposure as of the measurement date. Noncontrolling Interests Our consolidated noncontrolling interests are comprised of interests in COPLP not owned by COPT and interests in consolidated real estate joint ventures not owned by us (discussed further in Note 6). We evaluate whether noncontrolling interests are subject to redemption features outside of our control. We classify noncontrolling interests that are currently redeemable for cash at the option of the holders or are probable of becoming redeemable as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets; we adjust these interests each period to the greater of their fair value or carrying amount (initial amount as adjusted for allocations of income and losses and contributions and distributions), with a corresponding offset to additional paid-in capital on our consolidated balance sheets. Our other noncontrolling interests are reported in the equity section of our consolidated balance sheets. Revenue Recognition Lease and Other Property Revenue We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases usually include options under which the tenant may renew its lease based on market rates at the time of renewal, which are then typically subject to further negotiation. These leases occasionally provide the tenant with an option to terminate its lease early usually for a defined termination fee. Most of our lease revenue is from fixed contractual payments defined under the lease that, in most cases, escalate annually over the term of the lease. Our lease revenue also includes variable lease payments predominantly for tenant reimbursements of property operating expenses and lease termination fees. Property operating expense reimbursement structures vary, with some tenants responsible for all of a property’s expenses, while others are responsible for their share of a property’s expense only to the extent such expenses exceed amounts defined in the lease (which are derived from the property’s historical expense levels). Lease termination fees in most cases result from a tenant’s exercise of an existing right under a lease. Upon lease commencement, we evaluate leases to determine if they meet criteria set forth in lease accounting guidance for classification as sales-type leases or direct financing leases; if a lease meets none of these criteria, we classify the lease as an operating lease. Upon commencement of sales-type leases, we derecognize the underlying asset, recognizing in its place a net investment in the lease equal to the sum of the lease receivable and the present value of any unguaranteed residual asset and recognize any selling profit or loss created as a result of the difference between those two amounts. Similarly, for direct financing leases, we would derecognize the underlying asset and recognize a net investment in the lease, but, unlike in a sales-type lease, would defer profit and amortize it as interest income over the lease term. Our leases of properties as lessor are predominantly classified as operating leases, for which the underlying asset remains on our balance sheet and is depreciated consistently with other owned assets, with income recognized as described below. We recognize minimum rents on operating leases, net of abatements, on a straight-line basis over the term of tenant leases. A lease term commences when: (1) the tenant has control of the leased space (legal right to use the property); and (2) we have delivered the premises to the tenant as required under the terms of the lease. The term of a lease includes the noncancellable periods of the lease along with periods covered by: (1) a tenant option to extend the lease if the tenant is reasonably certain to exercise that option; (2) a tenant option to terminate the lease if the tenant is reasonably certain not to exercise that option; and (3) an option to extend (or not to terminate) the lease in which exercise of the option is controlled by us as the lessor. When assessing the expected lease end date, we use judgment in contemplating the significance of: any penalties a tenant may incur should it choose not to exercise any existing options to extend the lease or exercise any existing options to terminate the lease; and economic incentives for the tenant based on any existing contract, asset, entity or market-based factors in the lease. While a significant portion of our portfolio is leased to the USG, and the majority of those leases consist of a series of one-year renewal options, or provide for early termination rights, we have concluded that exercise of existing renewal options, or continuation of such leases without exercising early termination rights, is reasonably certain for most of these leases. We elected a practical expedient available under lease accounting guidance that enables us to combine non-lease components that otherwise would need to be accounted for under revenue accounting guidance (such as tenant reimbursements of property operating expenses) with the associated lease components for our accounting and reporting of operating lease revenue. We report the amount by which our minimum rental revenue recognized on a straight-line basis under leases exceeds the contractual rent billings associated with such leases as deferred rent receivable on our consolidated balance sheets. Amounts by which our minimum rental revenue recognized on a straight-line basis under leases are less than the contractual rent billings associated with such leases are reported in liabilities as deferred revenue associated with operating leases on our consolidated balance sheets. In connection with a tenant’s entry into, or modification of, a lease, if we make cash payments to, or on behalf of, the tenant for purposes other than funding the construction of landlord assets, we generally defer the amount of such payments as lease incentives. As discussed above, when we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets; if the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset. We amortize lease incentives as a reduction of rental revenue over the term of the lease. If collectability under a lease is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. We recognize lease revenue associated with tenant expense recoveries in the same periods in which we incur the related expenses, including tenant reimbursements of property taxes, utilities and other property operating expenses. We recognize fees received for lease terminations as revenue and write off against such revenue any (1) deferred rents receivable, and (2) deferred revenue, lease incentives and intangible assets that are amortizable into lease revenue associated with such leases; the resulting net amount is the net revenue from the early termination of the leases. When a tenant’s lease for space in a property is terminated early but the tenant continues to lease such space under a new or modified lease in the property, the net revenue from the early termination of the lease is recognized evenly over the remaining life of the new or modified lease in place on that property. Construction Contract and Other Service Revenues We enter into construction contracts to complete various design and construction services primarily for our USG tenants. The revenues and expenses from these services consist primarily of subcontracted costs that are reimbursed to us by our customers along with a fee. These services are an ancillary component of our overall operations, with small operating margins relative to the revenue. We review each contract to determine the performance obligations and allocate the transaction price based on the standalone selling price, as discussed further below. We recognize revenue under these contracts as services are performed in an amount that reflects the consideration we expect to receive in exchange for those services. Our performance obligations are satisfied over time as work progresses. Revenue recognition is determined using the input method based on costs incurred as of a point in time relative to the total estimated costs at completion to measure progress toward satisfying our performance obligations. We believe incurred costs of work performed best depicts the transfer of control of the services being transferred to the customer. In determining whether the performance obligations associated with a construction contract should be accounted for separately versus together, we consider numerous factors that may require significant judgment, including: whether the components contracted are substantially the same with the same pattern of transfer; whether the customer could contract with another party to perform construction based on our design project; and whether the customer can elect not to move forward after the design phase of the contract. Most of our contracts have a single performa

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value MeasurementsAccounting standards define fair value as the exit price, or the amount that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. The standards also establish a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of us. Unobservable inputs are inputs that reflect our assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available in the circumstances. The hierarchy of these inputs is broken down into three levels: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs include (1) quoted prices for similar assets or liabilities in active markets, (2) quoted prices for identical or similar assets or liabilities in inactive markets and (3) inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly; and Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is most significant to the fair value measurement. Recurring Fair Value Measurements We have a non-qualified elective deferred compensation plan for Trustees and certain members of our management team that, prior to December 31, 2019, permitted participants to defer up to 100% of their compensation on a pre-tax basis and receive a tax-deferred return on such deferrals. Effective December 31, 2019, no new investments of deferred compensation were eligible for the plan. The assets held in the plan (comprised primarily of mutual funds and equity securities) and the corresponding liability to the participants are measured at fair value on a recurring basis on our consolidated balance sheets using quoted market prices, as are other marketable securities that we hold. The balance of the plan, which was fully funded, totaled $1.8 million as of December 31, 2022 and $2.6 million as of December 31, 2021, and is included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets along with an insignificant amount of other marketable securities. The offsetting liability associated with the plan is adjusted to fair value at the end of each accounting period based on the fair value of the plan assets and reported in “other liabilities” on our consolidated balance sheets. The assets of the plan are classified in Level 1 of the fair value hierarchy, while the offsetting liability is classified in Level 2 of the fair value hierarchy. The fair values of our interest rate derivatives are determined using widely accepted valuation techniques, including a discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate market data and implied volatilities in such interest rates. While we determined that the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our interest rate derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default. However, as of December 31, 2022 and 2021, we assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivatives and determined that these adjustments were not significant. As a result, we determined that our interest rate derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The carrying values of cash and cash equivalents, restricted cash, accounts receivable, other assets (excluding investing receivables) and accounts payable and accrued expenses are reasonable estimates of their fair values because of the short maturities of these instruments. The fair values of our investing receivables, as disclosed in Note 8, were based on the discounted estimated future cash flows of the loans (categorized within Level 3 of the fair value hierarchy); the discount rates used approximate current market rates for loans with similar maturities and credit quality, and the estimated cash payments include scheduled principal and interest payments. For our disclosure of debt fair values in Note 10, we estimated the fair value of our unsecured senior notes based on quoted market rates for our senior notes (categorized within Level 1 of the fair value hierarchy) and estimated the fair value of our other debt based on the discounted estimated future cash payments to be made on such debt (categorized within Level 3 of the fair value hierarchy); the discount rates used approximate current market rates for loans, or groups of loans, with similar maturities and credit quality, and the estimated future payments include scheduled principal and interest payments. Fair value estimates are made as of a specific point in time, are subjective in nature and involve uncertainties and matters of significant judgment. For additional fair value information, refer to Note 8 for investing receivables, Note 10 for debt and Note 11 for interest rate derivatives. The table below sets forth our financial assets and liabilities accounted for at fair value on a recurring basis as of December 31, 2022 and 2021 and the hierarchy level of inputs used in measuring their respective fair values under applicable accounting standards (in thousands): Description Quoted Prices in Significant Other Significant Total December 31, 2022: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 1,762 $ — $ — $ 1,762 Other 69 — — 69 Interest rate derivatives (1) — 2,631 — 2,631 Total assets $ 1,831 $ 2,631 $ — $ 4,462 Liabilities: Deferred compensation plan liability (2) $ — $ 1,831 $ — $ 1,831 December 31, 2021: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 2,485 $ — $ — $ 2,485 Other 71 — — 71 Other marketable securities (1) 33 — — 33 Interest rate derivatives (1) — 355 — 355 Total assets $ 2,589 $ 355 $ — $ 2,944 Liabilities: Deferred compensation plan liability (2) $ — $ 2,556 $ — $ 2,556 Interest rate derivatives — 3,644 — 3,644 Total liabilities $ — $ 6,200 $ — $ 6,200 (1) Included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. (2) Included in the line entitled “other liabilities” on our consolidated balance sheets.

Properties, Net

Properties, Net	12 Months Ended
	Dec. 31, 2022
Real Estate [Abstract]
Properties, Net	Properties, Net Operating properties, net, excluding properties held for sale, consisted of the following (in thousands): December 31, 2022 2021 Land $ 539,809 $ 572,900 Buildings and improvements 3,986,524 3,670,133 Less: Accumulated depreciation (1,267,434) (1,152,523) Operating properties, net $ 3,258,899 $ 3,090,510 Our properties held for sale included: • as of December 31, 2022, three data center shell properties in Northern Virginia in which we sold a 90% interest and retained a 10% interest through a newly-formed joint venture on January 10, 2023; and • as of December 31, 2021, 9651 Hornbaker Road in Manassas, Virginia, our wholesale data center investment that we sold on January 25, 2022. The table below sets forth the components of assets classified as held for sale on our consolidated balance sheets (in thousands): December 31, 2022 2021 Properties, net $ 156,691 $ 191,857 Deferred rent receivable 4,595 462 Deferred leasing costs, net — 307 Intangible assets on property acquisitions, net — 73 Assets held for sale, net $ 161,286 $ 192,699 2022 Dispositions and Discontinued Operations On January 25, 2022, we sold 9651 Hornbaker Road in Manassas, Virginia, our sole wholesale data center investment, for $222.5 million, resulting in a gain on sale For the Years Ended December 31, 2022 2021 2020 Revenues from real estate operations $ 1,980 $ 30,490 $ 27,011 Property operating expenses (971) (16,842) (13,044) Depreciation and amortization associated with real estate operations — (10,290) (11,690) Gain on sale of real estate 28,564 — — Discontinued operations 29,573 3,358 2,277 Cash flows from operating activities $ 5,757 $ 10,930 $ 16,051 Cash flows from investing activities $ 220,565 $ (1,912) $ (11,485) On December 14, 2022, we sold a 90% interest in two data center shell properties in Northern Virginia based on an aggregate property value of $67.0 million and retained a 10% interest in the properties through Quark JV LLC (“Quark”), a newly-formed joint venture. Our partner in the joint venture acquired the 90% interest from us for $60.3 million. We account for our interest in the joint venture using the equity method of accounting as described further in Note 6. We recognized a gain on sale 2022 Development Activities In 2022, we placed into service 1.3 million square feet in nine newly-developed properties and 14,000 square feet in an expansion of one fully-operational property. As of December 31, 2022, we had seven properties under development, including two partially-operational properties, that we estimate will total 1.0 million square feet upon completion. 2021 Dispositions On June 2, 2021, we sold a 90% interest in two data center shell properties in Northern Virginia based on an aggregate property value of $118.8 million and retained a 10% interest in the properties through B RE COPT DC JV III LLC (“BRE-COPT 3”), a newly-formed joint venture. Our partner in the joint venture acquired the 90% interest from us for $106.9 million. We account for our interest in the joint venture using the equity method of accounting as described further in Note 6. We recognized a gain on sale On December 30, 2021, we sold a property that was previously removed from service from our data center shells sub-segment for $30.0 million and recognized a gain on sale 2021 Development Activities In 2021, we placed into service 766,000 square feet in eight newly-developed properties. 2020 Dispositions On October 30, 2020, we sold a 90% interest in two data center shell properties in Northern Virginia based on an aggregate property value of $89.7 million and retained a 10% interest in the properties through B RE COPT DC JV II LLC (“BRE-COPT 2”), a newly-formed joint venture. Our partner in the joint venture acquired the 90% interest from us for $80.7 million. We account for our interest in the joint venture using the equity method of accounting as described further in Note 6. We recognized a gain on sale 2020 Development Activities In 2020, we placed into service 1.8 million square feet in 11 newly-developed properties, 42,000 square feet in expansions of three fully-operational properties and 21,000 square feet in a redeveloped property. In the third quarter of 2020, we concluded that we no longer expected to develop a property in Baltimore, Maryland. As a result, we recognized an impairment loss on previously incurred pre-development costs of $1.5 million.

Leases

Leases	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2022 2021 2020 Fixed $ 453,907 $ 436,768 $ 404,244 Variable 126,262 116,900 104,870 $ 580,169 $ 553,668 $ 509,114 (1) Excludes lease revenue from discontinued operations of which $1.5 million, $22.3 million and $21.3 million was fixed and $527,000, $8.2 million and $5.7 million was variable for 2022, 2021 and 2020, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 37% in 2022, 36% in 2021 and 37% in 2020 of our total lease revenue, and 27% in 2022, 26% in 2021 and 27% in 2020 of our fixed lease revenue. Our lease revenue from the USG in 2022, 2021 and 2020 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 15). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2022 Year Ending December 31, Operating leases Sales-type leases 2023 $ 443,092 $ 960 2024 415,914 960 2025 336,522 960 2026 269,778 960 2027 236,079 960 Thereafter 1,114,240 2,596 Total contractual payments $ 2,815,625 7,396 Less: Amount representing interest (1,730) Net investment in sales-type leases $ 5,666 Lessee Arrangements As of December 31, 2022, our balance sheet included $39.2 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 26 years to 78 years (excluding extension options). As of December 31, 2022, our right-of-use assets included: • $11.4 million for land in a business park in Huntsville, Alabama under 17 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 40 to 49 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.7 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 77 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 26 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.0 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 60 to 71 years; • $3.6 million for data center space in Phoenix, Arizona with a remaining term of two years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.1 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 45 years, all of the rent on which was previously paid. The table below sets forth our property right-of-use assets and property lease liabilities on our consolidated balance sheets (in thousands): As of December 31, Leases Balance Sheet Location 2022 2021 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 37,020 $ 38,361 Finance leases - Property Prepaid expenses and other assets, net 2,207 2,238 Total right-of-use assets $ 39,227 $ 40,599 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 28,759 $ 29,342 As of December 31, 2022, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.19%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2022 2021 2020 Operating lease cost Property leases - fixed Property operating expenses $ 4,114 $ 4,011 $ 2,413 Property leases - variable Property operating expenses 65 45 127 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 31 34 $ 4,210 $ 4,087 $ 2,574 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2022 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,355 $ 3,206 $ 1,694 Financing cash flows for financing leases $ — $ 14 $ 674 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2022 2023 $ 3,399 2024 3,451 2025 1,797 2026 1,578 2027 1,593 Thereafter 124,341 Total lease payments 136,159 Less: Amount representing interest (107,400) Lease liability $ 28,759
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2022 2021 2020 Fixed $ 453,907 $ 436,768 $ 404,244 Variable 126,262 116,900 104,870 $ 580,169 $ 553,668 $ 509,114 (1) Excludes lease revenue from discontinued operations of which $1.5 million, $22.3 million and $21.3 million was fixed and $527,000, $8.2 million and $5.7 million was variable for 2022, 2021 and 2020, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 37% in 2022, 36% in 2021 and 37% in 2020 of our total lease revenue, and 27% in 2022, 26% in 2021 and 27% in 2020 of our fixed lease revenue. Our lease revenue from the USG in 2022, 2021 and 2020 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 15). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2022 Year Ending December 31, Operating leases Sales-type leases 2023 $ 443,092 $ 960 2024 415,914 960 2025 336,522 960 2026 269,778 960 2027 236,079 960 Thereafter 1,114,240 2,596 Total contractual payments $ 2,815,625 7,396 Less: Amount representing interest (1,730) Net investment in sales-type leases $ 5,666 Lessee Arrangements As of December 31, 2022, our balance sheet included $39.2 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 26 years to 78 years (excluding extension options). As of December 31, 2022, our right-of-use assets included: • $11.4 million for land in a business park in Huntsville, Alabama under 17 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 40 to 49 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.7 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 77 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 26 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.0 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 60 to 71 years; • $3.6 million for data center space in Phoenix, Arizona with a remaining term of two years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.1 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 45 years, all of the rent on which was previously paid. The table below sets forth our property right-of-use assets and property lease liabilities on our consolidated balance sheets (in thousands): As of December 31, Leases Balance Sheet Location 2022 2021 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 37,020 $ 38,361 Finance leases - Property Prepaid expenses and other assets, net 2,207 2,238 Total right-of-use assets $ 39,227 $ 40,599 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 28,759 $ 29,342 As of December 31, 2022, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.19%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2022 2021 2020 Operating lease cost Property leases - fixed Property operating expenses $ 4,114 $ 4,011 $ 2,413 Property leases - variable Property operating expenses 65 45 127 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 31 34 $ 4,210 $ 4,087 $ 2,574 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2022 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,355 $ 3,206 $ 1,694 Financing cash flows for financing leases $ — $ 14 $ 674 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2022 2023 $ 3,399 2024 3,451 2025 1,797 2026 1,578 2027 1,593 Thereafter 124,341 Total lease payments 136,159 Less: Amount representing interest (107,400) Lease liability $ 28,759
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2022 2021 2020 Fixed $ 453,907 $ 436,768 $ 404,244 Variable 126,262 116,900 104,870 $ 580,169 $ 553,668 $ 509,114 (1) Excludes lease revenue from discontinued operations of which $1.5 million, $22.3 million and $21.3 million was fixed and $527,000, $8.2 million and $5.7 million was variable for 2022, 2021 and 2020, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 37% in 2022, 36% in 2021 and 37% in 2020 of our total lease revenue, and 27% in 2022, 26% in 2021 and 27% in 2020 of our fixed lease revenue. Our lease revenue from the USG in 2022, 2021 and 2020 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 15). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2022 Year Ending December 31, Operating leases Sales-type leases 2023 $ 443,092 $ 960 2024 415,914 960 2025 336,522 960 2026 269,778 960 2027 236,079 960 Thereafter 1,114,240 2,596 Total contractual payments $ 2,815,625 7,396 Less: Amount representing interest (1,730) Net investment in sales-type leases $ 5,666 Lessee Arrangements As of December 31, 2022, our balance sheet included $39.2 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 26 years to 78 years (excluding extension options). As of December 31, 2022, our right-of-use assets included: • $11.4 million for land in a business park in Huntsville, Alabama under 17 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 40 to 49 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.7 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 77 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 26 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.0 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 60 to 71 years; • $3.6 million for data center space in Phoenix, Arizona with a remaining term of two years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.1 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 45 years, all of the rent on which was previously paid. The table below sets forth our property right-of-use assets and property lease liabilities on our consolidated balance sheets (in thousands): As of December 31, Leases Balance Sheet Location 2022 2021 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 37,020 $ 38,361 Finance leases - Property Prepaid expenses and other assets, net 2,207 2,238 Total right-of-use assets $ 39,227 $ 40,599 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 28,759 $ 29,342 As of December 31, 2022, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.19%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2022 2021 2020 Operating lease cost Property leases - fixed Property operating expenses $ 4,114 $ 4,011 $ 2,413 Property leases - variable Property operating expenses 65 45 127 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 31 34 $ 4,210 $ 4,087 $ 2,574 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2022 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,355 $ 3,206 $ 1,694 Financing cash flows for financing leases $ — $ 14 $ 674 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2022 2023 $ 3,399 2024 3,451 2025 1,797 2026 1,578 2027 1,593 Thereafter 124,341 Total lease payments 136,159 Less: Amount representing interest (107,400) Lease liability $ 28,759
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2022 2021 2020 Fixed $ 453,907 $ 436,768 $ 404,244 Variable 126,262 116,900 104,870 $ 580,169 $ 553,668 $ 509,114 (1) Excludes lease revenue from discontinued operations of which $1.5 million, $22.3 million and $21.3 million was fixed and $527,000, $8.2 million and $5.7 million was variable for 2022, 2021 and 2020, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 37% in 2022, 36% in 2021 and 37% in 2020 of our total lease revenue, and 27% in 2022, 26% in 2021 and 27% in 2020 of our fixed lease revenue. Our lease revenue from the USG in 2022, 2021 and 2020 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 15). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2022 Year Ending December 31, Operating leases Sales-type leases 2023 $ 443,092 $ 960 2024 415,914 960 2025 336,522 960 2026 269,778 960 2027 236,079 960 Thereafter 1,114,240 2,596 Total contractual payments $ 2,815,625 7,396 Less: Amount representing interest (1,730) Net investment in sales-type leases $ 5,666 Lessee Arrangements As of December 31, 2022, our balance sheet included $39.2 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 26 years to 78 years (excluding extension options). As of December 31, 2022, our right-of-use assets included: • $11.4 million for land in a business park in Huntsville, Alabama under 17 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 40 to 49 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.7 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 77 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 26 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.0 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 60 to 71 years; • $3.6 million for data center space in Phoenix, Arizona with a remaining term of two years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.1 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 45 years, all of the rent on which was previously paid. The table below sets forth our property right-of-use assets and property lease liabilities on our consolidated balance sheets (in thousands): As of December 31, Leases Balance Sheet Location 2022 2021 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 37,020 $ 38,361 Finance leases - Property Prepaid expenses and other assets, net 2,207 2,238 Total right-of-use assets $ 39,227 $ 40,599 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 28,759 $ 29,342 As of December 31, 2022, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.19%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2022 2021 2020 Operating lease cost Property leases - fixed Property operating expenses $ 4,114 $ 4,011 $ 2,413 Property leases - variable Property operating expenses 65 45 127 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 31 34 $ 4,210 $ 4,087 $ 2,574 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2022 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,355 $ 3,206 $ 1,694 Financing cash flows for financing leases $ — $ 14 $ 674 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2022 2023 $ 3,399 2024 3,451 2025 1,797 2026 1,578 2027 1,593 Thereafter 124,341 Total lease payments 136,159 Less: Amount representing interest (107,400) Lease liability $ 28,759

Real Estate Joint Ventures

Real Estate Joint Ventures	12 Months Ended
	Dec. 31, 2022
Equity Method Investments and Joint Ventures [Abstract]
Real Estate Joint Ventures	Real Estate Joint Ventures Consolidated Real Estate Joint Ventures The table below sets forth information as of December 31, 2022 pertaining to our investments in consolidated real estate joint ventures, which are each variable interest entities (dollars in thousands): Nominal Ownership % December 31, 2022 (1) Date Acquired Total Encumbered Assets Total Liabilities Mortgage Debt Entity Location LW Redstone Company, LLC (2) 3/23/2010 85% Huntsville, Alabama $ 595,565 $ 88,646 $ 118,375 $ 52,014 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 168,819 — 854 — M Square Associates, LLC 6/26/2007 50% College Park, Maryland 100,417 59,401 51,042 49,799 $ 864,801 $ 148,047 $ 170,271 $ 101,813 (1) Excludes amounts eliminated in consolidation. (2) As discussed below, we fund all capital requirements. Our partner receives distributions of the first $1.2 million of annual operating cash flows and we receive the remainder. Each of these joint ventures are engaged in the development and operation of real estate. We consolidate these joint ventures because of our: (1) power to direct the matters that most significantly impact their activities, including development, leasing and management of their properties; and (2) right to receive returns on our fundings and, in many cases, the obligation to fund the activities of the ventures to the extent that third-party financing is not obtained, both of which could be potentially significant to them. With regard to these joint ventures: • for LW Redstone Company, LLC, we anticipate funding certain infrastructure costs (up to a maximum of $76.0 million excluding accrued interest thereon) due to be reimbursed by the City of Huntsville as discussed further in Note 8. We had advanced $70.4 million to the City through December 31, 2022 to fund such costs. We also expect to fund additional development costs through equity contributions to the extent that third party financing is not obtained. Our partner was credited with $9.0 million in invested capital upon formation and is not required to make, nor has it made, additional equity contributions. Cash flows are generally distributed to the partners as follows: (1) member loans and accrued interest; (2) cumulative preferred returns of 13.5% on our partner’s invested capital; (3) cumulative preferred returns of 13.5% on our invested capital; (4) return of our invested capital; (5) return of our partner’s invested capital; and (6) any remaining residual 85% to us and 15% to our partner. Our partner has the right to require us to acquire its interest for fair value; accordingly, we classify the fair value of our partner’s interest as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets. We have the right to acquire our partner’s interest at fair value upon the earlier of five years following the project’s achievement of a construction commencement threshold of 4.4 million square feet or March 2040; the project had achieved approximately 2.5 million square feet of construction commencement through December 31, 2022. Our partner has the right to receive some or all of the consideration for the acquisition of its interests in the form of common units in COPLP; • for Stevens Investors, LLC, net cash flows of this entity will be distributed to the partners as follows: (1) member loans and accrued interest; (2) pro rata return of the partners’ capital; (3) pro rata return of the partners’ respective unpaid preferred returns; and (4) varying splits of 85% to 60% to us and the balance to our partners as we reach specified return hurdles. Our partners have the right to require us to acquire some or all of their interests for fair value until June 2023; accordingly, we classify the fair value of our partners’ interest as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets. We and our partners each have the right to acquire each other’s interests at fair value beginning in December 2023. Our partners have the right to receive some or all of the consideration for the acquisition of their interests in the form of common units in COPLP; and • for M Square Associates, LLC, net cash flows of this entity are distributed to the partners as follows: (1) member loans and accrued interest; (2) our preferred return and capital contributions used to fund infrastructure costs; (3) the partners’ preferred returns and capital contributions used to fund all other costs in proportion to their respective accrued returns and capital accounts; and (4) residual amounts distributed 50% to each member. We disclose the activity of our redeemable noncontrolling interests in Note 12. Unconsolidated Real Estate Joint Ventures The table below sets forth information pertaining to our investments in unconsolidated real estate joint ventures accounted for using the equity method of accounting (dollars in thousands): Date Acquired Nominal Ownership % Number of Properties Carrying Value of Investment as of December 31, Entity 2022 (1) 2021 BREIT COPT DC JV LLC 6/20/2019 10% 9 $ 11,568 $ 12,460 Quark 12/14/2022 10% 2 6,758 — BRE-COPT 3 6/2/2021 10% 2 3,134 11,850 BRE-COPT 2 (2) 10/30/2020 10% 8 (1,459) 15,579 21 $ 20,001 $ 39,889 (1) Included $21.5 million reported in “Investment in unconsolidated real estate joint ventures” and $1.5 million for investments with deficit balances reported in “other liabilities” on our consolidated balance sheet. (2) Our investment in BRE-COPT 2 was lower than our share of the joint venture’s equity by $7.0 million as of December 31, 2022 and $7.2 million as of December 31, 2021 due to a difference between our cost basis and our share of the joint venture’s underlying equity in its net assets. We recognize adjustments to our share of the joint venture’s earnings and losses resulting from this basis difference in the underlying assets of the joint venture. These joint ventures operate triple-net leased, single-tenant data center shell properties in Northern Virginia. With regard to these joint ventures: • BRE-COPT 2 was formed in 2020, when, as described further in Note 4, we sold a 90% interest in two properties and retained a 10% interest in the properties through the joint venture. As discussed below, this joint venture acquired an additional six properties through a transaction completed on December 22, 2020; • BRE-COPT 3 was formed in 2021, when, as described further in Note 4, we sold a 90% interest in two properties and retained a 10% interest in the properties through the joint venture; and • Quark was formed in 2022, when, as described further in Note 4, we sold a 90% interest in two properties and retained a 10% interest in the properties through the joint venture. We concluded that these joint ventures are variable interest entities. Under the terms of the joint venture agreements, we and our partners receive returns in proportion to our investments, and our maximum exposure to losses is limited to our investments, subject to certain indemnification obligations with respect to nonrecourse debt secured by the properties. The nature of our involvement in the activities of the joint venture does not give us power over decisions that significantly affect its economic performance. We previously also owned a 50% interest in GI-COPT DC Partnership LLC (“GI-COPT”), an unconsolidated joint venture that owned and operated six data center shell properties in Northern Virginia. On December 22, 2020, we sold, through a series of transactions, 80% of our 50% interests in the properties and associated mortgage debt that we owned through GI-COPT. We received $60 million in proceeds and a 10% retained interest in the LLCs through BRE-COPT 2, and recognized a gain of $29.4 million on the sale of these interests. GI-COPT was dissolved upon completion of these transactions.

Intangible Assets on Property A

Intangible Assets on Property Acquisitions	12 Months Ended
	Dec. 31, 2022
Intangible Assets on Property Acquisitions
Intangible Assets on Property Acquisitions	Intangible Assets on Property Acquisitions Intangible assets on property acquisitions consisted of the following (in thousands): December 31, 2022 December 31, 2021 Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net In-place lease value $ 125,207 $ 120,178 $ 5,029 $ 125,591 $ 118,983 $ 6,608 Tenant relationship value 57,210 52,803 4,407 58,082 50,701 7,381 Above-market leases 13,718 13,476 242 13,718 13,435 283 Other 1,333 1,052 281 1,333 1,038 295 $ 197,468 $ 187,509 $ 9,959 $ 198,724 $ 184,157 $ 14,567

Investing Receivables

Investing Receivables	12 Months Ended
	Dec. 31, 2022
Receivables [Abstract]
Investing Receivables	Investing Receivables Investing receivables consisted of the following (in thousands): December 31, 2022 2021 Notes receivable from the City of Huntsville $ 69,703 $ 77,784 Other investing loans receivable 17,712 6,041 Amortized cost basis 87,415 83,825 Allowance for credit losses (2,794) (1,599) Investing receivables, net $ 84,621 $ 82,226 The balances above include accrued interest receivable Our notes receivable from the City of Huntsville funded infrastructure costs in connection with our LW Redstone Company, LLC joint venture (see Note 6) and carry an interest rate of 9.95%. These notes and the accrued and unpaid interest thereon, which compounds annually on March 1, will be repaid using the real estate taxes generated by the properties developed by the joint venture. When these tax revenues are sufficient to cover the debt service on a certain increment of municipal bonds, the City of Huntsville will be required to issue bonds to repay the notes and the accrued and unpaid interest thereon. Each note has a maturity date of the earlier of 30 years from the date issued or the expiration of the tax increment district comprising the developed properties in 2045. Our other investing loans receivable as of December 31, 2022 carry interest rates ranging from 8.0% to 14.0% and mature within one year. The fair value of these receivables was approximately $87 million as of December 31, 2022 and $84 million as of December 31, 2021.

Prepaid Expenses and Other Asse

Prepaid Expenses and Other Assets, Net	12 Months Ended
	Dec. 31, 2022
Prepaid Expense and Other Assets [Abstract]
Prepaid Expenses and Other Assets, Net	Prepaid Expenses and Other Assets, Net Prepaid expenses and other assets, net consisted of the following (in thousands): December 31, 2022 2021 Construction contract costs in excess of billings, net $ 22,331 $ 22,384 Prepaid expenses 21,058 20,058 Furniture, fixtures and equipment, net 8,286 9,599 Non-real estate equity investments 5,974 5,544 Net investment in sales-type leases 5,666 6,194 Deferred financing costs, net (1) 5,210 1,314 Deposits 4,616 3,910 Restricted cash 4,172 4,054 Interest rate derivatives 2,631 355 Property - finance right-of-use assets 2,207 2,238 Marketable securities in deferred compensation plan 1,831 2,556 Deferred tax asset, net 1,405 1,841 Other assets 1,230 1,443 Prepaid expenses and other assets, net $ 86,617 $ 81,490 (1) Represents deferred costs, net of accumulated amortization, attributable to our Revolving Credit Facility and interest rate derivatives . Deferred tax asset, net reported above includes the following tax effects of temporary differences and carry forwards of our TRS (in thousands): December 31, 2022 2021 Operating loss carry forward $ 1,533 $ 1,835 Property (128) 30 Valuation allowance — (24) Deferred tax asset, net $ 1,405 $ 1,841 We recognize a valuation allowance on our deferred tax asset if we believe that all, or some portion, of the asset may not be realized. An increase or decrease in the valuation allowance resulting from a change in circumstances that causes a change in our judgment about the realizability of our deferred tax asset is included in income. We believe it is more likely than not that the results of future operations in our TRS will generate sufficient taxable income to realize our December 31, 2022 net deferred tax asset.

Debt, Net

Debt, Net	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Debt, Net	Debt, Net Debt Summary Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of December 31, December 31, 2022 2022 2021 Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed rate mortgage debt $ 84,433 $ 86,960 3.82% - 4.62% (2) 2023-2026 Variable rate secured debt 33,318 33,667 SOFR + 0.10% + 1.45% to 1.55% (3) 2025-2026 Total mortgage and other secured debt 117,751 120,627 Revolving Credit Facility (4) 211,000 76,000 SOFR + 0.10% + 0.725% to 1.400% (5) October 2026 Term Loan Facilities (4) 123,948 299,420 SOFR + 0.10% + 0.850% to 1.700% (6) January 2026 Unsecured Senior Notes (4) 2.25%, $400,000 aggregate principal 396,539 395,491 2.25% (7) March 2026 2.00%, $400,000 aggregate principal 396,988 396,512 2.00% (8) January 2029 2.75%, $600,000 aggregate principal 590,123 589,060 2.75% (9) April 2031 2.90%, $400,000 aggregate principal 394,848 394,441 2.90% (10) December 2033 Unsecured note payable 597 753 0% (11) May 2026 Total debt, net $ 2,231,794 $ 2,272,304 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $5.4 million as of December 31, 2022 and $5.8 million as of December 31, 2021. (2) The weighted average interest rate on our fixed rate mortgage debt was 4.07% as of December 31, 2022. (3) The weighted average interest rate on our variable rate secured debt as of December 31, 2022 was 5.58%, or 2.45% including the effect of interest rate swaps that hedge the risk of interest rate changes on this debt. (4) Refer to the paragraphs below for further disclosure. (5) The weighted average interest rate on the Revolving Credit Facility was 5.47% as of December 31, 2022. (6) The interest rate on this loan was 5.72% as of December 31, 2022. (7) The carrying value of these notes reflects an unamortized discount totaling $2.8 million as of December 31, 2022 and $3.6 million as of December 31, 2021 The effective interest rate under the notes, including amortization of the issuance costs, was 2.48%. (8) The carrying value of these notes reflects an unamortized discount totaling $2.1 million as of December 31, 2022 and $2.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.09%. (9) The carrying value of these notes reflects an unamortized discount totaling $8.5 million as of December 31, 2022 and $9.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.94%. (10) The carrying value of these notes reflects an unamortized discount totaling $4.2 million as of December 31, 2022 and $4.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 3.01%. (11) This note carries an interest rate that, upon assumption, was below market rates and it therefore was recorded at its fair value based on applicable effective interest rates. The carrying value of this note reflects an unamortized discount totaling $65,000 as of December 31, 2022 and $108,000 as of December 31, 2021. All debt is owed by the Operating Partnership. While COPT is not directly obligated by any debt, it has guaranteed COPLP’s Revolving Credit Facility, Term Loan Facility and Unsecured Senior Notes. Certain of our debt instruments require that we comply with a number of restrictive financial covenants, including maximum leverage ratio, unencumbered leverage ratio, minimum fixed charge coverage ratio, minimum unencumbered interest coverage ratio, minimum debt service and maximum secured indebtedness ratio. In addition, the terms of some of COPLP’s debt may limit its ability to make certain types of payments and other distributions to COPT in the event of default or when such payments or distributions may prompt failure of debt covenants, unless such distributions are required to maintain COPT’s qualification as a REIT. As of December 31, 2022, we were compliant with these financial covenants. Our debt matures on the following schedule (in thousands): Year Ending December 31, December 31, 2022 2023 $ 18,954 2024 29,983 2025 23,717 2026 782,300 2027 — Thereafter 1,400,000 Total $ 2,254,954 (1) (1) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $23.2 million. We capitalized interest costs of $6.7 million in 2022, $6.5 million in 2021 and $12.1 million in 2020. The following table sets forth information pertaining to the fair value of our debt (in thousands): December 31, 2022 December 31, 2021 Carrying Estimated Carrying Estimated Fixed-rate debt Unsecured Senior Notes $ 1,778,498 $ 1,433,561 $ 1,775,504 $ 1,809,950 Other fixed-rate debt 85,030 80,330 87,713 87,339 Variable-rate debt 368,266 367,896 409,087 409,639 $ 2,231,794 $ 1,881,787 $ 2,272,304 $ 2,306,928 Revolving Credit Facility On October 26, 2022, we entered into a credit agreement with a group of lenders for an unsecured revolving credit facility with a lender commitment of $600.0 million that replaced our existing unsecured revolving credit facility (the prior facility and new facility are referred to collectively herein as our “Revolving Credit Facility”). The facility matures on October 26, 2026, with the ability for us to extend such maturity by two six-month periods at our option, provided that there is no default under the facility and we pay an extension fee of 0.0625% of the total availability under the facility for each extension period. The interest rate on the facility is based on the Secured Overnight Financing Rate (“SOFR”) plus a SOFR index adjustment of 0.10% plus 0.725% to 1.400%, as determined by the credit ratings assigned to COPLP by Standard & Poor’s Ratings Services, Moody’s Investors Service, Inc. or Fitch Ratings Ltd. (collectively, the “Ratings Agencies”). The facility also carries a quarterly fee that is based on the lenders’ commitment under the facility multiplied by a per annum rate of 0.125% to 0.300%, as determined by the credit ratings assigned to COPLP by the Ratings Agencies. As of December 31, 2022, the maximum borrowing capacity under this facility totaled $600.0 million, of which $389.0 million was available. Weighted average borrowings under our Revolving Credit Facility totaled $202.8 million in 2022 and $135.8 million in 2021. The weighted average interest rate on our Revolving Credit Facility was 3.31% in 2022 and 1.18% in 2021. Term Loan Facilities The credit agreement with a group of lenders entered into on October 26, 2022 discussed above provided for a $125.0 million unsecured term loan with an interest rate based on SOFR plus a SOFR index adjustment of 0.10% plus 0.850% to 1.700%, as determined by the credit ratings assigned to COPLP by the Ratings Agencies. This term loan facility matures on January 30, 2026, with the ability for us to extend such maturity by two 12-month periods at our option, provided that there is no default under the facility and we pay an extension fee of 0.125% of the outstanding loan balance for each extension period. In addition to the term loan discussed above, we also had a term loan that we amended in 2020 to increase the loan amount by $150.0 million for a balance outstanding of $400.0 million. We repaid $100.0 million of this loan in 2021 and the remaining $300.0 million in 2022. Unsecured Senior Notes During 2020 and 2021, we issued the following unsecured senior notes: • $400.0 million of 2.25% Senior Notes due 2026 (the “2.25% Notes”) at an initial offering price of 99.42% of their face value on September 17, 2020, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $395.3 million. The notes mature on March 15, 2026; • $600.0 million of 2.75% Senior Notes due 2031 (the “2.75% Notes”) at an initial offering price of 98.95% of their face value on March 11, 2021, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $589.8 million. The notes mature on April 15, 2031; • $400.0 million of 2.00% Senior Notes due 2029 (the “2.00% Notes”) at an initial offering price of 99.97% of their face value on August 11, 2021, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $397.4 million. The notes mature on January 15, 2029; and • $400.0 million of 2.90% Senior Notes due 2033 (the “2.90% Notes”) at an initial offering price of 99.53% of their face value on November 17, 2021, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $395.4 million. The notes mature on December 1, 2033. We may redeem our unsecured senior notes, in whole at any time or in part from time to time, at our option, at a redemption price equal to the greater of (1) the aggregate principal amount of the notes being redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest thereon (not including any portion of such payments of interest accrued as of the date of redemption) discounted to its present value, on a semi-annual basis at an adjusted treasury rate plus a spread (35 basis points for the 2.25% Notes, 25 basis points for the 2.75% Notes, 20 basis points for the 2.00% Notes and 25 basis points for the 2.90% Notes), plus, in each case, accrued and unpaid interest thereon to the date of redemption. However, in each case, if this redemption occurs on or after a defined date (February 15, 2026 for the 2.25% Notes, January 15, 2031 for the 2.75% Notes, November 15, 2028 for the 2.00% Notes and September 1, 2033 for the 2.90% Notes), the redemption price will be equal to 100% of the principal amount of the notes being redeemed, plus accrued and unpaid interest thereon to, but not including, the applicable redemption date. These notes are unconditionally guaranteed by COPT. During 2020 and 2021, we purchased or redeemed the following unsecured senior notes: • purchased pursuant to a tender offer $122.9 million of our 3.70% Senior Notes due 2021 (the “3.70% Notes”) on September 17, 2020 for $126.0 million, plus accrued interest; and redeemed the remaining $177.1 million of the 3.70% Notes on October 19, 2020 for $180.9 million plus accrued interest. In connection with this purchase and redemption, we recognized a loss on early extinguishment of debt of $7.3 million in 2020; • purchased pursuant to tender offers $184.4 million of 3.60% Senior Notes due 2023 (the “3.60% Notes”) for $196.7 million and $145.6 million of 5.25% Senior Notes due 2024 (the “5.25% Notes”) for $164.7 million, plus accrued interest effective March 11, 2021; and on April 12, 2021, redeemed the remaining $165.6 million of 3.60% Notes for $176.3 million and $104.4 million of 5.25% Notes for $117.7 million, plus accrued interest. In connection with these purchases and redemptions, we recognized a loss on early extinguishment of debt of $58.4 million in 2021; and • redeemed $300.0 million of 5.00% Senior Notes due 2025 on November 18, 2021 for $336.4 million plus accrued interest. We recognized a loss on early extinguishment of debt of $38.2 million for this redemption in 2021.

Interest Rate Derivatives

Interest Rate Derivatives	12 Months Ended
	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest Rate Derivatives	Interest Rate Derivatives The following table sets forth the key terms and fair values of our interest rate swap derivatives (dollars in thousands): Notional Amount Effective Date Expiration Date Fair Value at December 31, Fixed Rate Floating Rate Index 2022 2021 $ 10,880 (1) 1.678 % SOFR plus 0.10% 8/1/2019 8/1/2026 $ 806 $ (234) $ 22,775 (2) 0.573 % SOFR plus 0.10% 4/1/2020 3/26/2025 1,825 355 $ 100,000 1.901 % One-Month LIBOR 9/1/2016 12/1/2022 — (1,361) $ 100,000 1.905 % One-Month LIBOR 9/1/2016 12/1/2022 — (1,365) $ 50,000 (3) 1.908 % One-Month LIBOR 9/1/2016 N/A — (684) $ 2,631 $ (3,289) (1) The notional amount of this instrument is scheduled to amortize to $10.0 million. Effective December 1, 2022, we amended this swap to change the floating rate index from one-month LIBOR to SOFR plus 0.10%. We made elections under reference rate reform related accounting guidance to not result in a dedesignation of this hedging relationship. (2) The notional amount of this instrument is scheduled to amortize to $22.1 million. Effective December 1, 2022, we amended this swap to change the floating rate index from one-month LIBOR to SOFR plus 0.10%. We made elections under reference rate reform related accounting guidance to not result in a dedesignation of this hedging relationship. (3) We cash settled this swap and accrued interest thereon for $625,000 on January 28, 2022. Each of these swaps was designated as a cash flow hedge of interest rate risk except for the swap with a $50.0 million notional amount. We discontinued hedge accounting for this swap effective in December 2021 when we determined that some of its hedged forecasted transactions were probable not to occur due to our entry into a contract to sell our wholesale data center and the debt pay down expected upon completion of the sale. This resulted in our reclassification of $221,000 in losses from AOCL to interest expense in our statement of operations. The table below sets forth the fair value of our interest rate derivatives as well as their classification on our consolidated balance sheets (in thousands): Fair Value at December 31, Derivatives Balance Sheet Location 2022 2021 Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 2,631 $ 355 Interest rate swaps designated as cash flow hedges Other liabilities $ — $ (2,960) Interest rate swap not designated Other liabilities $ — $ (684) The tables below present the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of Income (Loss) Recognized in AOCI/AOCL on Derivatives Amount of Loss Reclassified from AOCI/AOCL into Interest Expense on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2022 2021 2020 2022 2021 2020 Interest rate derivatives $ 4,730 $ 1,379 $ (39,454) $ (996) $ (5,048) $ (3,725) Amount of Loss Reclassified from AOCL into Loss on Interest Rate Derivatives on Statement of Operations Amount of Loss Recognized on Undesignated Swaps in Loss on Interest Rate Derivatives on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2022 2021 2020 2022 2021 2020 Interest rate derivatives $ — $ — $ (51,865) $ — $ — $ (1,265) As described further in Note 10, in September 2020, we completed our issuance of the 2.25% Notes. In August 2020, in anticipation of pursuing such an issuance, we determined that the forecasted transactions hedged by three interest rate swaps with an effective date of June 30, 2020 and an aggregate notional amount of $225.0 million were no longer probable of occurring, resulting in our discontinuance of hedge accounting on these swaps. When we consummated the note issuance in September 2020, we determined that it was probable that the forecasted transactions would not occur, resulting in our reclassification of $51.9 million in losses from AOCL to loss on interest rate derivatives on our statements of operations. On September 22, 2020, we cash settled these swaps and accrued interest thereon for an aggregate amount of $53.1 million. Based on the fair value of our derivatives as of December 31, 2022, we estimate that approximately $1.3 million of gains will be reclassified from AOCI as a decrease to interest expense over the next 12 months. We have agreements with each of our interest rate derivative counterparties that contain provisions under which, if we default or are capable of being declared in default on defined levels of our indebtedness, we could also be declared in default on our derivative obligations. Failure to comply with the loan covenant provisions could result in our being declared in default on any derivative instrument obligations covered by the agreements. As of December 31, 2022, we were not in default with any of these provisions. As of December 31, 2022, we did not have any derivatives in liability positions.

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests	12 Months Ended
	Dec. 31, 2022
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	Redeemable Noncontrolling Interests As discussed further in Note 6, our partners in two real estate joint ventures, LW Redstone Company, LLC and Stevens Investors, LLC, have the right to require us to acquire their respective interests at fair value; accordingly, we classify the fair value of our partners’ interests as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets. The table below sets forth the activity for these redeemable noncontrolling interests (in thousands): For the Years Ended December 31, 2022 2021 2020 Beginning balance $ 26,898 $ 25,430 $ 29,431 Distributions to noncontrolling interests (2,976) (3,307) (14,034) Net income attributable to noncontrolling interests 2,807 3,160 3,426 Adjustment to arrive at fair value of interests (436) 1,615 6,607 Ending balance $ 26,293 $ 26,898 $ 25,430

Equity

Equity	12 Months Ended
	Dec. 31, 2022
Stockholders' Equity Note [Abstract]
Equity	Equity Preferred Shares As of December 31, 2022, we had 25.0 million preferred shares authorized and unissued at $0.01 par value per share. Common Shares In May 2022, we entered into an at-the-market (“ATM”) stock offering program (the “2022 ATM Program”) that replaced a similar program established in 2018 (the “2018 ATM Program”) because we replaced the registration statement under which the 2018 ATM Program was registered with a new registration statement. Under the 2022 ATM Program, we may offer and sell common shares in at-the-market stock offerings having an aggregate gross sales price of up to $300 million and may also, at our discretion, sell common shares under forward equity sales agreements. As of December 31, 2022, we had not issued any shares under the 2022 ATM Program. Certain holders of COPLP common units converted their units into common shares on the basis of one common share for each common unit in the amount of 8,054 in 2021 and 14,009 in 2020. No COPLP common units were converted in 2022. We declared dividends per common share of $1.10 in 2022, 2021 and 2020. We pay dividends at the discretion of our Board of Trustees. Our ability to pay cash dividends will be dependent upon: (1) the cash flow generated from our operations; (2) cash generated or used by our financing and investing activities; and (3) the annual distribution requirements under the REIT provisions of the Code described in Note 2 and such other factors as the Board of Trustees deems relevant. Our ability to make cash dividends will also be limited by the terms of COPLP’s Partnership Agreement, as well as by limitations imposed by state law. In addition, we are prohibited from paying cash dividends in excess of the amount necessary for us to qualify for taxation as a REIT if a default or event of default exists pursuant to the terms of the credit agreement underlying our Revolving Credit Facility and unsecured term loan; this restriction does not currently limit our ability to pay dividends, and we do not believe that this restriction is reasonably likely to limit our ability to pay future dividends because we expect to comply with the terms of this agreement. See Note 14 for disclosure of common share activity pertaining to our share-based compensation plans.

Share-Based Compensation and Ot

Share-Based Compensation and Other Compensation Matters	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation and Other Compensation Matters	Share-Based Compensation and Other Compensation Matters Share-Based Compensation Plans In May 2017, we adopted the 2017 Omnibus Equity and Incentive Plan following the approval of such plan by our common shareholders, and we amended the plan in November 2018 (as amended, the “2017 Plan”). We may issue equity-based awards under this plan to officers, employees, non-employee trustees and any other key persons of us and our subsidiaries, as defined in the plan. The plan provides for a maximum of 3.4 million of our common shares to be issued in the form of options, share appreciation rights, restricted share unit awards, restricted share awards, unrestricted share awards, PIUs, dividend equivalent rights and other equity-based awards and for the granting of cash-based awards. This plan expires on May 11, 2027. Shares for the 2017 Plan are issued under a registration statement on Form S-8 that became effective upon filing with the Securities and Exchange Commission. The table below sets forth our reporting for share based compensation cost (in thousands): For the Years Ended December 31, 2022 2021 2020 General, administrative and leasing expenses $ 7,643 $ 6,881 $ 5,385 Property operating expenses 1,147 1,098 1,119 Capitalized to development activities 847 719 556 Share-based compensation cost $ 9,637 $ 8,698 $ 7,060 The amounts included in our consolidated statements of operations for share-based compensation reflected an estimate of pre-vesting forfeitures of 0% for awards to our executives and non-employee Trustees and 8% for awards to all other employees. As of December 31, 2022, unrecognized compensation costs related to unvested awards included: • $5.1 million on restricted shares expected to be recognized over a weighted average period of approximately two years; • $3.7 million on PB-PIUs expected to be recognized over a weighted average performance period of approximately two years; • $3.0 million on TB-PIUs expected to be recognized over a weighted average period of approximately two years; and • $85,000 on deferred share awards expected to be recognized through October 2023. Restricted Shares The following table summarizes restricted shares under the share-based compensation plans for 2020, 2021 and 2022: Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2019 392,863 $ 27.49 Granted 166,918 $ 25.22 Forfeited (25,773) $ 27.12 Vested (173,191) $ 28.14 Unvested as of December 31, 2020 360,817 $ 26.16 Granted 177,995 $ 26.17 Forfeited (39,664) $ 26.62 Vested (164,575) $ 25.95 Unvested as of December 31, 2021 334,573 $ 26.22 Granted 186,515 $ 26.50 Forfeited (43,420) $ 26.47 Vested (152,585) $ 26.39 Unvested as of December 31, 2022 325,083 $ 26.27 Unvested shares as of December 31, 2022 that are expected to vest 297,282 $ 26.25 Restricted shares granted to employees vest based on increments and over periods of time set forth under the terms of the respective awards provided that the employee remains employed by us. Restricted shares granted to non-employee Trustees vest on the first anniversary of the grant date, provided that the Trustee remains in his or her position. The aggregate intrinsic value of restricted shares that vested was $4.0 million in 2022, $4.3 million in 2021 and $4.4 million in 2020. PIUs We granted two forms of PIUs: TB-PIUs; and PB-PIUs. TB-PIUs are subject to forfeiture restrictions until the end of the requisite service period, at which time the TB-PIUs automatically convert into vested PIUs. PB-PIUs are subject to a market condition in that the number of earned awards are determined at the end of the performance period (as described further below) and then settled in vested PIUs. Vested PIUs carry substantially the same rights to redemption and distributions as non-PIU common units. TB-PIUs TB-PIUs granted to senior management team members vest based on increments and over periods of time set forth under the terms of the respective awards provided that the employee remains employed by us. TB-PIUs granted to non-employee Trustees vest on the first anniversary of the grant date, provided that the Trustee remains in his or her position. Prior to vesting, TB-PIUs carry substantially the same rights to distributions as non-PIU common units but carry no redemption rights. The following table summarizes TB-PIUs under the share-based compensation plan for 2020, 2021 and 2022 : Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2019 61,820 $ 26.01 Granted 98,318 $ 25.47 Forfeited (20,622) $ 25.50 Vested (25,182) $ 26.30 Unvested as of December 31, 2020 114,334 $ 25.57 Granted 93,983 $ 26.16 Vested (45,244) $ 25.28 Unvested as of December 31, 2021 163,073 $ 25.99 Granted 101,966 $ 26.39 Vested (77,709) $ 26.04 Unvested as of December 31, 2022 187,330 $ 26.19 Unvested TB-PIUs as of December 31, 2022 that are expected to vest 186,345 $ 26.19 The aggregate intrinsic value of TB-PIUs that vested was $2.0 million in 2022, $1.2 million in 2021 and $640,000 in 2020. PB-PIUs We made the following grants of PB-PIUs to senior management team members from 2019 through 2022 (dollars in thousands, except per share data): Grant Date Number of PB-PIUs Granted Grant Date Fair Value Number of PB-PIUs Outstanding as of December 31, 2022 1/1/2019 193,682 $ 2,415 — 1/1/2020 176,758 $ 2,891 141,152 1/1/2021 227,544 $ 3,417 227,544 1/1/2022 231,838 $ 3,810 231,838 The PB-PIUs each have a three-year performance period concluding on the earlier of the respective performance period end dates, or the date of: (1) termination by us without cause, death or disability of the employee or constructive discharge of the employee (collectively, “qualified termination”); or (2) a sale event. The number of earned awards at the end of the performance period will be determined based on the percentile rank of COPT’s total shareholder return (“TSR”) relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned Awards Payout % 75th or greater 100% of PB-PIUs granted 50th (target) 50% of PB-PIUs granted 25th 25% of PB-PIUs granted Below 25th 0% of PB-PIUs granted If the percentile rank exceeds the 25th percentile and is between two of the percentile ranks set forth in the table above, then the percentage of the earned awards will be interpolated between the ranges set forth in the table above to reflect any performance between the listed percentiles. If COPT’s TSR during the measurement period is negative, the maximum number of earned awards will be limited to the target level payout percentage. During the performance period, PB-PIUs carry rights to distributions equal to 10% of the distribution rights of non-PIU common units but carry no redemption rights. At the end of the performance period, we settle the award by issuing vested PIUs equal to the number of earned awards and either: • for awards granted January 1, 2019 and 2020, paying cash equal to the excess, if any, of: the aggregate distributions that would have been paid with respect to vested PIUs issued in settlement of the earned awards through the date of settlement had such vested PIUs been issued on the grant date; over the aggregate distributions made on the PB-PIUs during the performance period; or • for awards granted January 1, 2021 and 2022, issuing additional vested PIUs equal to the excess, if any, of (1) the aggregate distributions that would have been paid with respect to vested PIUs issued in settlement of the earned awards through the date of settlement had such vested PIUs been issued on the grant date over (2) the aggregate distributions made on the PB-PIUs during the performance period, divided by the price of our common shares on the settlement date. If a performance period ends due to a sale event or qualified termination, the number of earned awards is prorated based on the portion of the three-year performance period that has elapsed. If employment is terminated by the employee or by us for cause, all PB-PIUs are forfeited. Based on COPT’s TSR relative to its peer group of companies: • for the 2019 PB-PIUs issued to employees that vested on December 31, 2021, we issued 156,104 PIUs in settlement of the PB-PIUs on February 1, 2022; and • for the 2020 PB-PIUs issued to employees that vested on December 31, 2022, we issued 141,152 PIUs in settlement of the PB-PIUs on February 1, 2023. We computed grant date fair values for PB-PIUs using Monte Carlo models and recognize these values over the respective performance periods. The grant date fair value and certain of the assumptions used in the Monte Carlo models for the PB-PIUs granted in 2020, 2021 and 2022 are set forth below: Grant Date Grant Date Fair Value Per PB-PIU at Target-Level Award Baseline Common Share Value Expected Volatility of Common Shares Risk-free Interest Rate 1/1/2020 $ 32.71 $ 29.38 18.0 % 1.65 % 1/1/2021 $ 30.03 $ 26.08 34.7 % 0.18 % 1/1/2022 $ 32.87 $ 27.97 31.7 % 0.98 % Deferred Share Awards We made the following grants of deferred share awards to non-employee Trustees in 2020, 2021 and 2022 (dollars in thousands, except per share data): Year of Grant Number of Deferred Share Awards Granted Aggregate Grant Date Fair Value Grant Date Fair Value Per Award 2020 10,679 $ 253 $ 23.68 2021 3,416 $ 93 $ 27.12 2022 6,771 $ 166 $ 24.50 Deferred share awards vest on the first anniversary of the grant date, provided that the Trustee remains in his or her position. We settle deferred share awards by issuing an equivalent number of common shares upon vesting of the awards or a later date elected by the Trustee (generally upon cessation of being a Trustee). We did not have any award settlements in 2020, 2021 or 2022. PSUs As of December 31, 2022, we had no PSU grants outstanding. We last issued PSUs on January 1, 2018, when we granted executives 59,110 PSUs with a grant date fair value of $1.9 million and a three-year performance period. The number of PSUs earned (“earned PSUs”) at the end of the performance period were determined based on the percentile rank of COPT’s TSR relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned PSUs Payout % 75th or greater 200% of PSUs granted 50th (target) 100% of PSUs granted 25th 50% of PSUs granted Below 25th 0% of PSUs granted At the end of the performance period, we settled the award by issuing fully-vested COPT shares equal to the number of earned PSUs in settlement of the award plan and paid cash equal to the aggregate dividends that would have been paid with respect to the common shares issued in settlement of the earned PSUs through the date of settlement had such shares been issued on the grant date. Based on COPT’s TSR relative to its peer group of companies, for the 2018 PSUs that vested on December 31, 2020, we issued 93,824 common shares in settlement of the PSUs on February 3, 2021. We computed grant date fair values for PSUs using Monte Carlo models and recognized these values over the performance periods.

Information by Business Segment

Information by Business Segment	12 Months Ended
	Dec. 31, 2022
Segment Reporting [Abstract]
Information by Business Segment	Information by Business SegmentWe have the following reportable segments: Defense/IT Locations; Regional Office; Wholesale Data Center (the only property in which we sold on January 25, 2022); and Other. We also report on Defense/IT Locations sub-segments, which include the following: Fort George G. Meade and the Baltimore/Washington Corridor (“Fort Meade/BW Corridor”); NoVA Defense/IT; Lackland Air Force Base (in San Antonio); locations serving the U.S. Navy (“Navy Support”), which included properties proximate to the Washington Navy Yard, the Naval Air Station Patuxent River in Maryland and the Naval Surface Warfare Center Dahlgren Division in Virginia; Redstone Arsenal (in Huntsville); and data center shells (properties leased to tenants to be operated as data centers in which the tenants fund the costs for the power, fiber connectivity and data center infrastructure). Our segment reporting included below reflects our retrospective reclassification of two properties to our NoVA Defense/IT sub-segment from our Regional Office segment in the first quarter of 2022.We measure the performance of our segments through the measure we define as net operating income from real estate operations (“NOI from real estate operations”), which includes: real estate revenues and property operating expenses; and the net of revenues and property operating expenses of real estate operations owned through unconsolidated real estate joint ventures (“UJVs”) that is allocable to our ownership interest (“UJV NOI allocable to COPT”). Amounts reported for segment assets represent long-lived assets associated with consolidated operating properties (including the carrying value of properties, right-of-use assets, net of related lease liabilities, intangible assets, deferred leasing costs, deferred rents receivable and lease incentives) and the carrying value of investments in UJVs owning operating properties. Amounts reported as additions to long-lived assets represent additions to existing consolidated operating properties, excluding transfers from non-operating properties, which we report separately. The table below reports segment financial information for our reportable segments (in thousands): Defense/IT Locations Fort Meade/BW Corridor NoVA Defense/IT Lackland Air Force Base Navy Support Redstone Arsenal Data Center Shells Total Defense/IT Locations Regional Office Wholesale Other Total Year Ended December 31, 2022 Revenues from real estate operations $ 273,790 $ 73,985 $ 62,911 $ 32,754 $ 38,593 $ 35,722 $ 517,755 $ 59,316 $ 1,980 $ 7,327 $ 586,378 Property operating expenses (97,727) (26,635) (32,301) (14,001) (15,600) (4,372) (190,636) (31,712) (979) (5,074) (228,401) UJV NOI allocable to COPT — — — — — 4,327 4,327 — — — 4,327 NOI from real estate operations $ 176,063 $ 47,350 $ 30,610 $ 18,753 $ 22,993 $ 35,677 $ 331,446 $ 27,604 $ 1,001 $ 2,253 $ 362,304 Additions to long-lived assets $ 48,443 $ 11,102 $ — $ 3,801 $ 3,405 $ — $ 66,751 $ 37,625 $ (35) $ 185 $ 104,526 Transfers from non-operating properties $ 69,771 $ 1,882 $ 1,290 $ 6,420 $ 158,831 $ 179,522 $ 417,716 $ 704 $ — $ — $ 418,420 Segment assets at December 31, 2022 $ 1,387,517 $ 488,277 $ 194,481 $ 169,119 $ 453,543 $ 462,471 $ 3,155,408 $ 550,059 $ — $ 3,804 $ 3,709,271 Year Ended December 31, 2021 Revenues from real estate operations $ 262,120 $ 65,853 $ 57,756 $ 33,757 $ 35,727 $ 31,582 $ 486,795 $ 63,107 $ 30,490 $ 6,668 $ 587,060 Property operating expenses (92,521) (24,785) (30,535) (13,617) (11,618) (4,086) (177,162) (31,056) (17,424) (4,577) (230,219) UJV NOI allocable to COPT — — — — — 4,029 4,029 — — — 4,029 NOI from real estate operations $ 169,599 $ 41,068 $ 27,221 $ 20,140 $ 24,109 $ 31,525 $ 313,662 $ 32,051 $ 13,066 $ 2,091 $ 360,870 Additions to long-lived assets $ 45,647 $ 6,197 $ — $ 4,193 $ 3,542 $ — $ 59,579 $ 35,038 $ 1,680 $ 488 $ 96,785 Transfers from non-operating properties $ 70,514 $ 90,050 $ 59,323 $ — $ 22,739 $ 3,004 $ 245,630 $ 39,319 $ — $ — $ 284,949 Segment assets at December 31, 2021 $ 1,332,399 $ 489,582 $ 198,200 $ 170,985 $ 300,252 $ 350,098 $ 2,841,516 $ 537,268 $ 192,647 $ 4,031 $ 3,575,462 Year Ended December 31, 2020 Revenues from real estate operations $ 254,197 $ 61,685 $ 50,982 $ 32,869 $ 22,515 $ 29,139 $ 451,387 $ 56,759 $ 27,011 $ 3,568 $ 538,725 Property operating expenses (85,032) (22,996) (29,055) (12,655) (8,119) (3,195) (161,052) (27,469) (13,543) (1,776) (203,840) UJV NOI allocable to COPT — — — — — 6,951 6,951 — — — 6,951 NOI from real estate operations $ 169,165 $ 38,689 $ 21,927 $ 20,214 $ 14,396 $ 32,895 $ 297,286 $ 29,290 $ 13,468 $ 1,792 $ 341,836 Additions to long-lived assets $ 31,295 $ 12,314 $ — $ 7,104 $ 2,905 $ — $ 53,618 $ 16,538 $ 10,856 $ 467 $ 81,479 Transfers from non-operating properties $ 21,859 $ 2,557 $ 456 $ — $ 138,122 $ 230,277 $ 393,271 $ 83,091 $ — $ — $ 476,362 Segment assets at December 31, 2020 $ 1,277,849 $ 411,780 $ 142,137 $ 178,897 $ 281,386 $ 419,929 $ 2,711,978 $ 471,356 $ 201,820 $ 3,824 $ 3,388,978 The following table reconciles our segment revenues to total revenues as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 Segment revenues from real estate operations $ 586,378 $ 587,060 $ 538,725 Construction contract and other service revenues 154,632 107,876 70,640 Less: Revenues from discontinued operations (Note 4) (1,980) (30,490) (27,011) Total revenues $ 739,030 $ 664,446 $ 582,354 The following table reconciles our segment property operating expenses to property operating expenses as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 Segment property operating expenses $ 228,401 $ 230,219 $ 203,840 Less: Property operating expenses from discontinued operations (Note 4) (971) (16,842) (13,044) Total property operating expenses $ 227,430 $ 213,377 $ 190,796 The following table reconciles UJV NOI allocable to COPT to equity in income of unconsolidated entities as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 UJV NOI allocable to COPT $ 4,327 $ 4,029 $ 6,951 Less: Income from UJVs allocable to COPT attributable to depreciation and amortization expense, interest expense and gain on extinguishment of debt (3,145) (2,930) (5,120) Add: Equity in income (loss) of unconsolidated non-real estate entities 561 (6) (6) Equity in income of unconsolidated entities $ 1,743 $ 1,093 $ 1,825 As previously discussed, we provide real estate services such as property management, development and construction services primarily for our properties but also for third parties. The primary manner in which we evaluate the operating performance of our service activities is through a measure we define as net operating income from service operations (“NOI from service operations”), which is based on the net of revenues and expenses from these activities. Construction contract and other service revenues and expenses consist primarily of subcontracted costs that are reimbursed to us by the customer along with a management fee. The operating margins from these activities are small relative to the revenue. We believe NOI from service operations is a useful measure in assessing both our level of activity and our profitability in conducting such operations. The table below sets forth the computation of our NOI from service operations (in thousands): For the Years Ended December 31, 2022 2021 2020 Construction contract and other service revenues $ 154,632 $ 107,876 $ 70,640 Construction contract and other service expenses (149,963) (104,053) (67,615) NOI from service operations $ 4,669 $ 3,823 $ 3,025 The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to income from continuing operations as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 NOI from real estate operations $ 362,304 $ 360,870 $ 341,836 NOI from service operations 4,669 3,823 3,025 Depreciation and other amortization associated with real estate operations (141,230) (137,543) (126,503) General, administrative and leasing expenses (35,798) (36,127) (33,001) Business development expenses and land carry costs (3,193) (4,647) (4,473) Impairment losses — — (1,530) Interest expense (61,174) (65,398) (67,937) Interest and other income 9,341 7,879 8,574 Credit loss (expense) recoveries (271) 1,128 933 Gain on sales of real estate 19,250 65,590 30,209 Gain on sale of investment in unconsolidated real estate joint venture — — 29,416 Loss on early extinguishment of debt (609) (100,626) (7,306) Loss on interest rate derivatives — — (53,196) Equity in income of unconsolidated entities 1,743 1,093 1,825 UJV NOI allocable to COPT included in equity in income of unconsolidated entities (4,327) (4,029) (6,951) Income tax expense (447) (145) (353) Revenues from real estate operations from discontinued operations (Note 4) (1,980) (30,490) (27,011) Property operating expenses from discontinued operations (Note 4) 971 16,842 13,044 Income from continuing operations $ 149,249 $ 78,220 $ 100,601 The following table reconciles our segment assets to our consolidated total assets (in thousands): As of December 31, 2022 2021 Segment assets $ 3,709,271 $ 3,575,462 Operating properties lease liabilities included in segment assets 28,759 29,342 Non-operating property assets 301,002 449,144 Other assets 218,243 208,504 Total consolidated assets $ 4,257,275 $ 4,262,452 The accounting policies of the segments are the same as those used to prepare our consolidated financial statements, except that discontinued operations are not presented separately for segment purposes. In the segment reporting presented above, we did not allocate interest expense, depreciation and amortization, impairment losses, gain on sales of real estate, gain on sale of investment in unconsolidated real estate joint venture, loss on early extinguishment of debt, loss on interest rate derivatives and equity in income of unconsolidated entities not included in NOI to our real estate segments since they are not included in the measure of segment profit reviewed by management. We also did not allocate general, administrative and leasing expenses, business development expenses and land carry costs, interest and other income, credit loss (expense) recoveries, income taxes and noncontrolling interests because these items represent general corporate or non-operating property items not attributable to segments.

Construction Contract and Other

Construction Contract and Other Service Revenues	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Construction Contract and Other Service Revenues	Construction Contract and Other Service Revenues We disaggregate our construction contract and other service revenues by compensation arrangement and by service type as we believe it best depicts the nature, timing and uncertainty of our revenue. The table below reports construction contract and other service revenues by compensation arrangement (in thousands): For the Years Ended December 31, 2022 2021 2020 Construction contract revenue: GMP $ 129,149 $ 68,113 $ 22,032 FFP 15,119 13,897 12,373 Cost-plus fee 8,320 24,260 34,025 Other 2,044 1,606 2,210 $ 154,632 $ 107,876 $ 70,640 The table below reports construction contract and other service revenues by service type (in thousands): For the Years Ended December 31, 2022 2021 2020 Construction contract revenue: Construction $ 151,694 $ 104,020 $ 66,087 Design 894 2,250 2,343 Other 2,044 1,606 2,210 $ 154,632 $ 107,876 $ 70,640 We derived 90% of our construction contract revenue from the USG in 2022, 79% in 2021 and 55% in 2020. We recognized an insignificant amount of revenue in 2022, 2021 and 2020 from performance obligations satisfied (or partially satisfied) in previous periods. Accounts receivable related to our construction contract services is included in accounts receivable, net on our consolidated balance sheets. The beginning and ending balances of accounts receivable related to our construction contracts were as follows (in thousands): For the Years Ended December 31, 2022 2021 Beginning balance $ 7,193 $ 13,997 Ending balance $ 7,618 $ 7,193 Contract assets, which we refer to herein as construction contract costs in excess of billings, net, are included in prepaid expenses and other assets, net on our consolidated balance sheets. The beginning and ending balances of our contract assets were as follows (in thousands): For the Years Ended December 31, 2022 2021 Beginning balance $ 22,384 $ 10,343 Ending balance $ 22,331 $ 22,384 Contract liabilities are included in other liabilities on our consolidated balance sheets. Changes in contract liabilities were as follows (in thousands): For the Years Ended December 31, 2022 2021 Beginning balance $ 2,499 $ 4,610 Ending balance $ 2,867 $ 2,499 Portion of beginning balance recognized in revenue during the year $ 278 $ 2,664 Revenue allocated to the remaining performance obligations under existing contracts as of December 31, 2022 that will be recognized as revenue in future periods was $67.9 million, of which we expect to recognize approximately $65 million in 2023.

Credit Losses on Financial Asse

Credit Losses on Financial Assets and Other Instruments	12 Months Ended
	Dec. 31, 2022
Credit Loss [Abstract]
Credit Losses on Financial Assets and Other Instruments	Credit Losses on Financial Assets and Other Instruments The table below sets forth the activity for our allowance for credit losses in 2020, 2021 and 2022 (in thousands): Investing Receivables Tenant Notes Other Assets (2) Off-Balance Sheet Credit Exposures Total December 31, 2019 $ — $ 97 $ — $ — $ 97 Cumulative effect of change for adoption of credit loss guidance 3,732 325 144 1,340 5,541 Credit loss (recoveries) expense (881) 729 559 (1,340) (933) Other changes — 52 (60) — (8) December 31, 2020 2,851 1,203 643 — 4,697 Credit loss (recoveries) expense (1,252) (146) 270 — (1,128) December 31, 2021 1,599 1,057 913 — 3,569 Credit loss expense (recoveries) 1,195 (279) (645) — 271 December 31, 2022 $ 2,794 $ 778 $ 268 $ — $ 3,840 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of December 31, 2022 and December 31, 2021 included $52,000 and $218,000, respectively, in the line entitled “accounts receivable, net” and $216,000 and $695,000, respectively, in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. The following table presents the amortized cost basis of our investing receivables, tenant notes receivable and sales-type lease receivables by credit risk classification, by origination year as of December 31, 2022 (in thousands): Origination Year 2017 and Earlier 2018 2019 2020 2021 2022 Total Investing receivables: Credit risk classification: Investment grade $ 60,437 $ — $ — $ 1,887 $ 7,379 $ — $ 69,703 Non-investment grade — — 15 — — 17,697 17,712 Total $ 60,437 $ — $ 15 $ 1,887 $ 7,379 $ 17,697 $ 87,415 Tenant notes receivable: Credit risk classification: Investment grade $ — $ 807 $ 40 $ 195 $ — $ — $ 1,042 Non-investment grade 151 98 89 1,565 — — 1,903 Total $ 151 $ 905 $ 129 $ 1,760 $ — $ — $ 2,945 Sales-type lease receivable: Credit risk classification: Investment grade $ — $ — $ — $ 5,666 $ — $ — $ 5,666 Our investment grade credit risk classification represents entities with investment grade credit ratings from ratings agencies (such as Standard & Poor’s Ratings Services, Moody’s Investors Service, Inc. or Fitch Ratings Ltd.), meaning that they are considered to have at least an adequate capacity to meet their financial commitments, with credit risk ranging from minimal to moderate. Our non-investment grade credit risk classification represents entities with either no credit agency credit ratings or ratings deemed to be sub-investment grade; we believe that there is significantly more credit risk associated with this classification. The credit risk classifications of our investing receivables and tenant notes receivable were last updated in December 2022. An insignificant portion of the investing and tenant notes receivables set forth above was past due, which we define as being delinquent by more than three months from the due date.

Earnings Per Share ("EPS")

Earnings Per Share ("EPS")	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Earnings Per Share ("EPS")	Earnings Per Share (“EPS”) We present both basic and diluted EPS. We compute basic EPS by dividing net income available to common shareholders allocable to unrestricted common shares under the two-class method by the weighted average number of unrestricted common shares outstanding during the period. Our computation of diluted EPS is similar except that: • the denominator is increased to include: (1) the weighted average number of potential additional common shares that would have been outstanding if securities that are convertible into common shares were converted; and (2) the effect of dilutive potential common shares outstanding during the period attributable to redeemable noncontrolling interests and share-based compensation awards using the if-converted or treasury stock methods; and • the numerator is adjusted to add back any changes in income or loss that would result from the assumed conversion into common shares that we add to the denominator. Summaries of the numerator and denominator for purposes of basic and diluted EPS calculations are set forth below (in thousands, except per share data): For the Years Ended December 31, 2022 2021 2020 Numerator: Income from continuing operations $ 149,249 $ 78,220 $ 100,601 Income from continuing operations attributable to noncontrolling interests (5,372) (4,994) (5,477) Income from continuing operations attributable to share-based compensation awards for basic EPS (451) (467) (433) Numerator for basic EPS from continuing operations attributable to COPT common shareholders $ 143,426 $ 72,759 $ 94,691 Redeemable noncontrolling interests (169) (128) — Adjustment to income from continuing operations attributable to share-based compensation awards for diluted EPS 78 44 27 Numerator for diluted EPS from continuing operations attributable to COPT common shareholders $ 143,335 $ 72,675 $ 94,718 Discontinued operations 29,573 3,358 2,277 Discontinued operations attributable to noncontrolling interests (421) (43) (27) Income from discontinued operations attributable to share-based compensation awards for diluted EPS (90) 6 2 Numerator for diluted EPS on net income attributable to COPT common shareholders $ 172,397 $ 75,996 $ 96,970 Denominator (all weighted averages): Denominator for basic EPS (common shares) 112,073 111,960 111,788 Dilutive effect of redeemable noncontrolling interests 116 128 — Dilutive effect of share-based compensation awards 431 330 288 Denominator for diluted EPS (common shares) 112,620 112,418 112,076 Basic EPS: Income from continuing operations attributable to COPT common shareholders $ 1.28 $ 0.65 $ 0.85 Discontinued operations attributable to COPT common shareholders 0.26 0.03 0.02 Net income attributable to COPT common shareholders $ 1.54 $ 0.68 $ 0.87 Diluted EPS: Income from continuing operations attributable to COPT common shareholders $ 1.27 $ 0.65 $ 0.85 Discontinued operations attributable to COPT common shareholders 0.26 0.03 0.02 Net income attributable to COPT common shareholders $ 1.53 $ 0.68 $ 0.87 Our diluted EPS computations do not include the effects of the following securities since the conversions of such securities would increase diluted EPS for the respective periods (in thousands): Weighted Average Shares Excluded from Denominator for the Years Ended December 31, 2022 2021 2020 Conversion of common units 1,454 1,257 1,236 Conversion of redeemable noncontrolling interests 866 804 957 Conversion of Series I Preferred Units — — 171 The following securities were also excluded from the computation of diluted EPS because their effect was antidilutive: • weighted average restricted shares and deferred share awards of 399,000 for 2022, 412,000 for 2021 and 430,000 for 2020; and • weighted average TB-PIUs of 187,000 for 2022, 158,000 for 2021 and 89,000 for 2020.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Claims In the normal course of business, we are subject to legal actions and other claims. We record losses for specific legal proceedings and claims when we determine that a loss is probable and the amount of loss can be reasonably estimated. As of December 31, 2022, management believes that it is reasonably possible that we could recognize a loss of up to $4 million for certain municipal tax claims; while we do not believe this loss would materially affect our financial position or liquidity, it could be material to our results of operations. Management believes that it is also reasonably possible that we could incur losses pursuant to other claims but do not believe such losses would materially affect our financial position, liquidity or results of operations. Our assessment of the potential outcomes of these matters involves significant judgment and is subject to change based on future developments. Environmental We are subject to various federal, state and local environmental regulations related to our property ownership and operations. We have performed environmental assessments of our properties, the results of which have not revealed any environmental liability that we believe would have a materially adverse effect on our financial position, operations or liquidity. In connection with a lease and subsequent sale in 2008 and 2010 of three properties in Dayton, New Jersey, we agreed to provide certain environmental indemnifications limited to $19 million in the aggregate. We have insurance coverage in place to mitigate most of any potential future losses that may result from these indemnification agreements. Tax Incremental Financing Obligation Anne Arundel County, Maryland issued tax incremental financing bonds to third-party investors in order to finance public improvements needed in connection with our project known as the National Business Park. These bonds had a remaining principal balance of approximately $29 million as of December 31, 2022. The real estate taxes on increases in assessed values post-bond issuance of properties in development districts encompassing the National Business Park are transferred to a special fund pledged to the repayment of the bonds. While we are obligated to fund, through a special tax, any future shortfalls between debt service of the bonds and real estate taxes available to repay the bonds, as of December 31, 2022, we do not expect any such future fundings will be required.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventOn January 10, 2023, we sold a 90% interest in three data center shell properties in Northern Virginia based on an aggregate property value of $211.3 million and retained a 10% interest in the properties through Redshift JV LLC, a newly-formed joint venture. Our partner in the joint venture acquired the 90% interest from us for $190.2 million. We recognized a gain on sale

Schedule III - Real Estate and

Schedule III - Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2022
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 Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 100 Light Street (O) Baltimore, MD $ — $ 26,715 $ 58,002 $ 45,315 $ 26,715 $ 103,317 $ 130,032 $ (30,601) 1973/2011 8/7/2015 100 Secured Gateway (O) Huntsville, AL — — 71,159 34 — 71,193 71,193 (4,121) 2020 3/23/2010 1000 Redstone Gateway (O) Huntsville, AL 8,880 — 20,533 108 — 20,641 20,641 (5,045) 2013 3/23/2010 1100 Redstone Gateway (O) Huntsville, AL 9,547 — 19,593 100 — 19,693 19,693 (4,408) 2014 3/23/2010 114 National Business Parkway (O) Annapolis Junction, MD — 364 3,109 427 364 3,536 3,900 (1,779) 2002 6/30/2000 1200 Redstone Gateway (O) Huntsville, AL 11,012 — 22,389 121 — 22,510 22,510 (5,077) 2013 3/23/2010 1201 M Street SE (O) Washington, DC — — 49,775 10,384 — 60,159 60,159 (23,155) 2001 9/28/2010 1201 Winterson Road (O) Linthicum, MD — 2,130 17,202 924 2,130 18,126 20,256 (6,403) 1985/2017 4/30/1998 1220 12th Street SE (O) Washington, DC — — 42,464 9,919 — 52,383 52,383 (21,522) 2003 9/28/2010 1243 Winterson Road (L) Linthicum, MD — 630 — — 630 — 630 — (6) 12/19/2001 131 National Business Parkway (O) Annapolis Junction, MD — 1,906 7,623 6,392 1,906 14,015 15,921 (8,472) 1990 9/28/1998 132 National Business Parkway (O) Annapolis Junction, MD — 2,917 12,259 4,984 2,917 17,243 20,160 (11,464) 2000 5/28/1999 133 National Business Parkway (O) Annapolis Junction, MD — 2,517 10,068 6,733 2,517 16,801 19,318 (11,461) 1997 9/28/1998 134 National Business Parkway (O) Annapolis Junction, MD — 3,684 7,517 5,958 3,684 13,475 17,159 (8,950) 1999 11/13/1998 1340 Ashton Road (O) Hanover, MD — 905 3,620 2,631 905 6,251 7,156 (3,639) 1989 4/28/1999 13450 Sunrise Valley Drive (O) Herndon, VA — 1,386 5,576 4,955 1,386 10,531 11,917 (7,040) 1998 7/25/2003 13454 Sunrise Valley Drive (O) Herndon, VA — 2,847 11,986 10,345 2,847 22,331 25,178 (13,637) 1998 7/25/2003 135 National Business Parkway (O) Annapolis Junction, MD — 2,484 9,750 7,085 2,484 16,835 19,319 (11,512) 1998 12/30/1998 1362 Mellon Road (O) Hanover, MD — 950 3,864 1,953 950 5,817 6,767 (1,577) 2006 2/10/2006 13857 McLearen Road (O) Herndon, VA — 3,507 30,177 5,715 3,507 35,892 39,399 (14,907) 2007 7/11/2012 140 National Business Parkway (O) Annapolis Junction, MD — 3,407 24,167 1,811 3,407 25,978 29,385 (12,361) 2003 12/31/2003 141 National Business Parkway (O) Annapolis Junction, MD — 2,398 9,538 4,832 2,398 14,370 16,768 (10,153) 1990 9/28/1998 14280 Park Meadow Drive (O) Chantilly, VA — 3,731 15,953 5,621 3,731 21,574 25,305 (11,413) 1999 9/29/2004 1460 Dorsey Road (L) Hanover, MD — 1,577 183 — 1,577 183 1,760 — (6) 2/28/2006 14840 Conference Center Drive (O) Chantilly, VA — 1,572 8,175 5,728 1,572 13,903 15,475 (8,420) 2000 7/25/2003 14850 Conference Center Drive (O) Chantilly, VA — 1,615 8,358 7,439 1,615 15,797 17,412 (8,032) 2000 7/25/2003 14900 Conference Center Drive (O) Chantilly, VA — 3,436 14,402 9,371 3,436 23,773 27,209 (14,901) 1999 7/25/2003 1501 South Clinton Street (O) Baltimore, MD — 27,964 51,990 44,816 27,964 96,806 124,770 (34,787) 2006 10/27/2009 15049 Conference Center Drive (O) Chantilly, VA — 4,415 20,365 17,846 4,415 38,211 42,626 (22,574) 1997 8/14/2002 15059 Conference Center Drive (O) Chantilly, VA — 5,753 13,615 6,313 5,753 19,928 25,681 (11,364) 2000 8/14/2002 1550 West Nursery Road (O) Linthicum, MD — 14,071 16,930 — 14,071 16,930 31,001 (7,047) 2009 10/28/2009 1560 West Nursery Road (O) Linthicum, MD — 1,441 113 — 1,441 113 1,554 (24) 2014 10/28/2009 1610 West Nursery Road (O) Linthicum, MD — 259 246 — 259 246 505 (36) 2016 4/30/1998 1616 West Nursery Road (O) Linthicum, MD — 393 3,323 75 393 3,398 3,791 (449) 2017 4/30/1998 1622 West Nursery Road (O) Linthicum, MD — 393 2,542 — 393 2,542 2,935 (372) 2016 4/30/1998 16442 Commerce Drive (O) Dahlgren, VA — 613 2,582 1,147 613 3,729 4,342 (2,134) 2002 12/21/2004 16480 Commerce Drive (O) Dahlgren, VA — 1,856 7,425 2,772 1,856 10,197 12,053 (5,203) 2000 12/28/2004 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 16501 Commerce Drive (O) Dahlgren, VA — 522 2,090 1,040 522 3,130 3,652 (1,689) 2002 12/21/2004 16539 Commerce Drive (O) Dahlgren, VA — 688 2,860 2,345 688 5,205 5,893 (3,190) 1990 12/21/2004 16541 Commerce Drive (O) Dahlgren, VA — 773 3,094 2,630 773 5,724 6,497 (3,261) 1996 12/21/2004 16543 Commerce Drive (O) Dahlgren, VA — 436 1,742 879 436 2,621 3,057 (1,467) 2002 12/21/2004 1751 Pinnacle Drive (O) McLean, VA — 10,486 42,339 34,512 10,486 76,851 87,337 (45,785) 1989/1995 9/23/2004 1753 Pinnacle Drive (O) McLean, VA — 8,275 34,353 25,142 8,275 59,495 67,770 (30,720) 1976/2004 9/23/2004 206 Research Boulevard (O) Aberdeen, MD — — — — — — — — 2012 9/14/2007 209 Research Boulevard (O) Aberdeen, MD — 134 1,711 543 134 2,254 2,388 (772) 2010 9/14/2007 210 Research Boulevard (O) Aberdeen, MD — 113 1,402 536 113 1,938 2,051 (610) 2010 9/14/2007 2100 L Street (O) Washington, DC — 57,385 94,784 — 57,385 94,784 152,169 (4,385) 2020 8/11/2015 2100 Rideout Road (O) Huntsville, AL — — 7,336 3,015 — 10,351 10,351 (2,760) 2016 3/23/2010 22289 Exploration Drive (O) Lexington Park, MD — 1,422 5,719 2,148 1,422 7,867 9,289 (4,585) 2000 3/24/2004 22299 Exploration Drive (O) Lexington Park, MD — 1,362 5,791 3,084 1,362 8,875 10,237 (5,531) 1998 3/24/2004 22300 Exploration Drive (O) Lexington Park, MD — 1,094 5,038 2,772 1,094 7,810 8,904 (4,640) 1997 11/9/2004 22309 Exploration Drive (O) Lexington Park, MD — 2,243 10,419 8,179 2,243 18,598 20,841 (9,668) 1984/1997 3/24/2004 23535 Cottonwood Parkway (O) California, MD — 692 3,051 648 692 3,699 4,391 (2,358) 1984 3/24/2004 250 W Pratt St (O) Baltimore, MD — 8,057 34,588 19,811 8,057 54,399 62,456 (22,224) 1985 3/19/2015 2600 Park Tower Drive (O) Vienna, VA — 20,284 34,443 5,977 20,284 40,420 60,704 (9,764) 1999 4/15/2015 2691 Technology Drive (O) Annapolis Junction, MD — 2,098 17,334 9,191 2,098 26,525 28,623 (13,031) 2005 5/26/2000 2701 Technology Drive (O) Annapolis Junction, MD — 1,737 15,266 7,118 1,737 22,384 24,121 (14,080) 2001 5/26/2000 2711 Technology Drive (O) Annapolis Junction, MD — 2,251 21,611 4,459 2,251 26,070 28,321 (16,361) 2002 11/13/2000 2720 Technology Drive (O) Annapolis Junction, MD — 3,863 29,272 3,219 3,863 32,491 36,354 (15,238) 2004 1/31/2002 2721 Technology Drive (O) Annapolis Junction, MD — 4,611 14,597 3,828 4,611 18,425 23,036 (11,406) 2000 10/21/1999 2730 Hercules Road (O) Annapolis Junction, MD — 8,737 31,612 9,540 8,737 41,152 49,889 (25,143) 1990 9/28/1998 30 Light Street (O) Baltimore, MD — — 12,101 1,056 — 13,157 13,157 (2,742) 2009 8/7/2015 300 Secured Gateway (O) Annapolis Junction, MD — — 25,384 — — 25,384 25,384 — (7) 3/23/2010 300 Sentinel Drive (O) Annapolis Junction, MD — 1,517 59,165 2,526 1,517 61,691 63,208 (20,225) 2009 11/14/2003 302 Sentinel Drive (O) Annapolis Junction, MD — 2,648 29,687 3,802 2,648 33,489 36,137 (12,102) 2007 11/14/2003 304 Sentinel Drive (O) Annapolis Junction, MD — 3,411 24,917 5,335 3,411 30,252 33,663 (13,355) 2005 11/14/2003 306 Sentinel Drive (O) Annapolis Junction, MD — 3,260 22,592 3,720 3,260 26,312 29,572 (11,085) 2006 11/14/2003 308 Sentinel Drive (O) Annapolis Junction, MD — 1,422 26,208 2,365 1,422 28,573 29,995 (8,761) 2010 11/14/2003 310 Sentinel Way (O) Annapolis Junction, MD — 2,372 43,312 — 2,372 43,312 45,684 (7,180) 2016 11/14/2003 310 The Bridge Street (O) Huntsville, AL — 261 26,530 5,958 261 32,488 32,749 (13,337) 2009 8/9/2011 312 Sentinel Way (O) Annapolis Junction, MD — 3,138 27,797 — 3,138 27,797 30,935 (5,779) 2014 11/14/2003 314 Sentinel Way (O) Annapolis Junction, MD — 1,254 7,741 — 1,254 7,741 8,995 (1,713) 2008 11/14/2003 316 Sentinel Way (O) Annapolis Junction, MD — 2,748 38,156 225 2,748 38,381 41,129 (10,394) 2011 11/14/2003 318 Sentinel Way (O) Annapolis Junction, MD — 2,185 28,426 562 2,185 28,988 31,173 (12,249) 2005 11/14/2003 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 320 Sentinel Way (O) Annapolis Junction, MD — 2,067 21,623 156 2,067 21,779 23,846 (8,206) 2007 11/14/2003 322 Sentinel Way (O) Annapolis Junction, MD — 2,605 22,827 1,900 2,605 24,727 27,332 (10,090) 2006 11/14/2003 324 Sentinel Way (O) Annapolis Junction, MD — 1,656 23,018 42 1,656 23,060 24,716 (7,109) 2010 6/29/2006 4000 Market Street (O) Huntsville, AL 5,993 — 9,198 396 — 9,594 9,594 (858) 2018 3/23/2010 410 National Business Parkway (O) Annapolis Junction, MD — 1,831 23,257 2,259 1,831 25,516 27,347 (7,048) 2012 6/29/2006 4100 Market Street (O) Huntsville, AL 5,217 — 8,049 7 — 8,056 8,056 (710) 2019 3/23/2010 420 National Business Parkway (O) Annapolis Junction, MD — 2,370 29,550 208 2,370 29,758 32,128 (6,217) 2013 6/29/2006 430 National Business Parkway (O) Annapolis Junction, MD — 1,852 21,563 2,950 1,852 24,513 26,365 (6,632) 2011 6/29/2006 44408 Pecan Court (O) California, MD — 817 1,583 1,751 817 3,334 4,151 (2,259) 1986 3/24/2004 44414 Pecan Court (O) California, MD — 405 1,619 1,149 405 2,768 3,173 (1,861) 1986 3/24/2004 44417 Pecan Court (O) California, MD — 434 3,822 180 434 4,002 4,436 (2,385) 1989/2015 3/24/2004 44420 Pecan Court (O) California, MD — 344 890 311 344 1,201 1,545 (667) 1989 11/9/2004 44425 Pecan Court (O) California, MD — 1,309 3,506 2,395 1,309 5,901 7,210 (4,076) 1997 5/5/2004 45310 Abell House Lane (O) California, MD — 2,272 13,808 1,386 2,272 15,194 17,466 (4,357) 2011 8/30/2010 4600 River Road (O) College Park, MD — — 24,573 — — 24,573 24,573 (1,049) 2020 1/29/2008 46579 Expedition Drive (O) Lexington Park, MD — 1,406 5,796 2,987 1,406 8,783 10,189 (4,897) 2002 3/24/2004 46591 Expedition Drive (O) Lexington Park, MD — 1,200 7,199 4,394 1,200 11,593 12,793 (5,181) 2005 3/24/2004 4851 Stonecroft Boulevard (O) Chantilly, VA — 1,878 11,558 223 1,878 11,781 13,659 (5,307) 2004 8/14/2002 540 National Business Parkway (O) Annapolis Junction, MD — 2,035 31,840 41 2,035 31,881 33,916 (4,124) 2017 6/29/2006 550 National Business Parkway (O) Annapolis Junction, MD — 2,678 30,363 — 2,678 30,363 33,041 — (7) 6/29/2006 5520 Research Park Drive (O) Catonsville, MD — — 20,072 1,979 — 22,051 22,051 (7,741) 2009 4/4/2006 5522 Research Park Drive (O) Catonsville, MD — — 4,550 855 — 5,405 5,405 (2,050) 2007 3/8/2006 560 National Business Parkway (O) Annapolis Junction, MD — 2,193 55,149 — 2,193 55,149 57,342 (233) 2022 6/29/2006 5801 University Research Court (O) College Park, MD 10,880 — 17,431 162 — 17,593 17,593 (2,294) 2018 1/29/2008 5825 University Research Court (O) College Park, MD 19,075 — 22,771 2,517 — 25,288 25,288 (8,978) 2008 1/29/2008 5850 University Research Court (O) College Park, MD 20,182 — 31,906 1,112 — 33,018 33,018 (10,623) 2008 1/29/2008 6000 Redstone Gateway (O) Huntsville, AL — — 8,532 17 — 8,549 8,549 (415) 2020 3/23/2010 610 Guardian Way (O) Annapolis Junction, MD — 7,636 53,574 — 7,636 53,574 61,210 (1,572) 2021 6/29/2006 6200 Redstone Gateway (O) Huntsville, AL — — 38,479 — — 38,479 38,479 — 2022 3/23/2010 6700 Alexander Bell Drive (O) Columbia, MD — 1,755 7,019 10,504 1,755 17,523 19,278 (10,285) 1988 5/14/2001 6708 Alexander Bell Drive (O) Columbia, MD — 897 12,693 1,618 897 14,311 15,208 (5,238) 1988/2016 5/14/2001 6711 Columbia Gateway Drive (O) Columbia, MD — 2,683 23,239 2,885 2,683 26,124 28,807 (10,779) 2006-2007 9/28/2000 6716 Alexander Bell Drive (O) Columbia, MD — 1,242 4,969 5,323 1,242 10,292 11,534 (6,718) 1990 12/31/1998 6721 Columbia Gateway Drive (O) Columbia, MD — 1,753 34,090 9,263 1,753 43,353 45,106 (13,231) 2009 9/28/2000 6724 Alexander Bell Drive (O) Columbia, MD — 449 5,039 2,491 449 7,530 7,979 (4,349) 2001 5/14/2001 6731 Columbia Gateway Drive (O) Columbia, MD — 2,807 19,098 6,351 2,807 25,449 28,256 (14,983) 2002 3/29/2000 6740 Alexander Bell Drive (O) Columbia, MD — 1,424 4,209 7,131 1,424 11,340 12,764 (2,773) 1992 12/31/1998 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 6741 Columbia Gateway Drive (O) Columbia, MD — 675 1,711 176 675 1,887 2,562 (762) 2008 9/28/2000 6750 Alexander Bell Drive (O) Columbia, MD — 1,263 12,461 6,050 1,263 18,511 19,774 (11,751) 2001 12/31/1998 6760 Alexander Bell Drive (O) Columbia, MD — 890 3,561 3,915 890 7,476 8,366 (5,348) 1991 12/31/1998 6940 Columbia Gateway Drive (O) Columbia, MD — 3,545 9,916 12,340 3,545 22,256 25,801 (12,733) 1999 11/13/1998 6950 Columbia Gateway Drive (O) Columbia, MD — 3,596 28,307 3,223 3,596 31,530 35,126 (13,441) 1998/2019 10/22/1998 7000 Columbia Gateway Drive (O) Columbia, MD — 3,131 12,103 10,451 3,131 22,554 25,685 (11,944) 1999 5/31/2002 7000 Redstone Gateway (O) Huntsville, AL — — 7,542 — — 7,542 7,542 — 2022 (7) 3/23/2010 7005 Columbia Gateway Drive (L) Columbia, MD — 3,036 747 — 3,036 747 3,783 — (6) 6/26/2014 7015 Albert Einstein Drive (O) Columbia, MD — 2,058 6,093 3,560 2,058 9,653 11,711 (5,447) 1999 12/1/2005 7061 Columbia Gateway Drive (O) Columbia, MD — 729 3,094 2,909 729 6,003 6,732 (3,806) 2000 8/30/2001 7063 Columbia Gateway Drive (O) Columbia, MD — 902 3,684 3,470 902 7,154 8,056 (4,975) 2000 8/30/2001 7065 Columbia Gateway Drive (O) Columbia, MD — 919 3,763 3,174 919 6,937 7,856 (4,846) 2000 8/30/2001 7067 Columbia Gateway Drive (O) Columbia, MD — 1,829 11,823 8,125 1,829 19,948 21,777 (10,234) 2001 8/30/2001 7100 Redstone Gateway (O) Huntsville, AL — — 12,983 — — 12,983 12,983 (514) 2021 3/23/2010 7125 Columbia Gateway Drive (O) Columbia, MD — 20,487 49,925 27,278 20,487 77,203 97,690 (32,510) 1973/1999 6/29/2006 7130 Columbia Gateway Drive (O) Columbia, MD — 1,350 4,359 3,029 1,350 7,388 8,738 (4,363) 1989 9/19/2005 7134 Columbia Gateway Drive (O) Columbia, MD — 704 4,700 817 704 5,517 6,221 (2,144) 1990/2016 9/19/2005 7138 Columbia Gateway Drive (O) Columbia, MD — 1,104 3,518 2,963 1,104 6,481 7,585 (4,506) 1990 9/19/2005 7142 Columbia Gateway Drive (O) Columbia, MD — 1,342 7,148 2,851 1,342 9,999 11,341 (4,803) 1994/2018 9/19/2005 7150 Columbia Gateway Drive (O) Columbia, MD — 1,032 3,429 1,659 1,032 5,088 6,120 (2,165) 1991 9/19/2005 7150 Riverwood Drive (O) Columbia, MD — 1,821 4,388 3,436 1,821 7,824 9,645 (3,316) 2000 1/10/2007 7160 Riverwood Drive (O) Columbia, MD — 2,732 7,006 4,609 2,732 11,615 14,347 (5,835) 2000 1/10/2007 7170 Riverwood Drive (O) Columbia, MD — 1,283 3,096 2,387 1,283 5,483 6,766 (3,002) 2000 1/10/2007 7175 Riverwood Drive (O) Columbia, MD — 1,788 7,269 — 1,788 7,269 9,057 (1,661) 1996/2013 7/27/2005 7200 Redstone Gateway (O) Huntsville, AL — — 8,348 81 — 8,429 8,429 (1,830) 2013 3/23/2010 7200 Riverwood Drive (O) Columbia, MD — 4,089 22,630 5,036 4,089 27,666 31,755 (14,245) 1986 10/13/1998 7205 Riverwood Drive (O) Columbia, MD — 1,367 21,419 — 1,367 21,419 22,786 (5,058) 2013 7/27/2005 7272 Park Circle Drive (O) Hanover, MD — 1,479 6,300 4,609 1,479 10,909 12,388 (6,471) 1991/1996 1/10/2007 7318 Parkway Drive (O) Hanover, MD — 972 3,888 2,284 972 6,172 7,144 (3,374) 1984 4/16/1999 7400 Redstone Gateway (O) Huntsville, AL — — 9,223 75 — 9,298 9,298 (1,756) 2015 3/23/2010 7467 Ridge Road (O) Hanover, MD — 1,565 3,116 6,876 1,565 9,992 11,557 (5,137) 1990 4/28/1999 7500 Advanced Gateway (O) Huntsville, AL — — 18,665 — — 18,665 18,665 (1,201) 2020 3/23/2010 7600 Advanced Gateway (O) Huntsville, AL — — 13,752 — — 13,752 13,752 (826) 2020 3/23/2010 7740 Milestone Parkway (O) Hanover, MD 15,942 3,825 34,176 1,262 3,825 35,438 39,263 (11,179) 2009 7/2/2007 7770 Backlick Road (O) Springfield, VA — 6,387 78,892 1,669 6,387 80,561 86,948 (19,584) 2012 3/10/2010 7880 Milestone Parkway (O) Hanover, MD — 4,857 27,175 1,617 4,857 28,792 33,649 (5,068) 2015 9/17/2013 8000 Rideout Road (O) Huntsville, AL — — 27,579 — — 27,579 27,579 (529) 2021 3/23/2010 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 8100 Rideout Road (O) Huntsville, AL — — 14,606 — — 14,606 14,606 — (7) 3/23/2010 8200 Rideout Road (O) Huntsville, AL — — 43,115 — — 43,115 43,115 — 2022 3/23/2010 8300 Rideout Road (O) Huntsville, AL — — 47,658 — — 47,658 47,658 — 2022 3/23/2010 8600 Advanced Gateway (O) Huntsville, AL — — 27,312 — — 27,312 27,312 (1,394) 2020 3/23/2010 8621 Robert Fulton Drive (O) Columbia, MD — 2,317 12,642 7,680 2,317 20,322 22,639 (9,467) 2005-2006 6/10/2005 8661 Robert Fulton Drive (O) Columbia, MD — 1,510 3,764 3,313 1,510 7,077 8,587 (4,129) 2002 12/30/2003 8671 Robert Fulton Drive (O) Columbia, MD — 1,718 4,280 4,848 1,718 9,128 10,846 (5,418) 2002 12/30/2003 870 Elkridge Landing Road (O) Linthicum, MD — 2,003 9,442 10,464 2,003 19,906 21,909 (13,432) 1981 8/3/2001 8800 Redstone Gateway (O) Huntsville, AL 11,565 — 18,470 — — 18,470 18,470 (1,437) 2019 3/23/2010 891 Elkridge Landing Road (O) Linthicum, MD — 1,165 4,772 3,994 1,165 8,766 9,931 (5,750) 1984 7/2/2001 901 Elkridge Landing Road (O) Linthicum, MD — 1,156 4,437 7,069 1,156 11,506 12,662 (5,724) 1984 7/2/2001 911 Elkridge Landing Road (O) Linthicum, MD — 1,215 4,861 3,347 1,215 8,208 9,423 (5,448) 1985 4/30/1998 938 Elkridge Landing Road (O) Linthicum, MD — 922 4,748 1,516 922 6,264 7,186 (3,619) 1984 7/2/2001 939 Elkridge Landing Road (O) Linthicum, MD — 939 3,756 4,687 939 8,443 9,382 (6,313) 1983 4/30/1998 Arundel Preserve (L) Hanover, MD — 13,352 9,844 — 13,352 9,844 23,196 — (6) 7/2/2007 Canton Crossing Land (L) Baltimore, MD — 17,285 8,438 1,076 17,285 9,514 26,799 (17) (6) 10/27/2009 Canton Crossing Util Distr Ctr (O) Baltimore, MD — 6,100 10,450 1,974 6,100 12,424 18,524 (7,510) 2006 10/27/2009 Columbia Gateway - Southridge (L) Columbia, MD — 6,387 3,725 — 6,387 3,725 10,112 — (6) 9/20/2004 Dahlgren Technology Center (L) Dahlgren, VA — 978 178 — 978 178 1,156 — (6) 3/16/2005 Expedition VII (O) Lexington Park, MD — 705 8,332 — 705 8,332 9,037 (113) 2022 (7) 3/24/2004 M Square Research Park (L) College Park, MD — — 3,230 — — 3,230 3,230 — (6) 1/29/2008 MR Land (L) Northern Virginia — 9,038 809 — 9,038 809 9,847 — (6) 11/8/2018 National Business Park North (L) Annapolis Junction, MD — 15,554 21,463 — 15,554 21,463 37,017 — (6) 6/29/2006 North Gate Business Park (L) Aberdeen, MD — 1,755 5 — 1,755 5 1,760 — (6) 9/14/2007 NoVA Office A (O) Chantilly, VA — 2,096 46,849 — 2,096 46,849 48,945 (9,266) 2015 7/18/2002 NoVA Office B (O) Chantilly, VA — 739 38,376 — 739 38,376 39,115 (5,695) 2016 7/18/2002 NoVA Office C (O) Chantilly, VA — 7,751 80,771 — 7,751 80,771 88,522 (2,472) 2021 7/18/2002 NoVA Office D (O) Chantilly, VA — 6,587 40,559 — 6,587 40,559 47,146 (5,483) 2017 7/2/2013 Oak Grove A (O) Northern Virginia — 12,866 41,488 — 12,866 41,488 54,354 (2,232) 2020 11/1/2018 Oak Grove B (O) Northern Virginia — 12,866 41,443 — 12,866 41,443 54,309 (2,866) 2019 11/1/2018 Oak Grove C (O) Northern Virginia — 11,741 77,526 — 11,741 77,526 89,267 (1,369) 2022 11/1/2018 Oak Grove D (O) Northern Virginia — 11,741 71,279 — 11,741 71,279 83,020 (260) 2022 11/1/2018 Old Annapolis Road (O) Columbia, MD — 1,637 5,500 6,902 1,637 12,402 14,039 (5,882) 1974/1985 12/14/2000 P2 A (O) (8) Northern Virginia — 16,853 40,159 — 16,853 40,159 57,012 (2,576) 2020 5/2/2019 P2 B (O) (8) Northern Virginia — 22,839 36,388 — 22,839 36,388 59,227 (1,953) 2020 5/2/2019 P2 C (O) (8) Northern Virginia — 14,869 31,597 — 14,869 31,597 46,466 (1,485) 2020 5/2/2019 Patriot Ridge (L) Springfield, VA — 18,517 14,599 — 18,517 14,599 33,116 — (6) 3/10/2010 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) Project EL (O) Confidential-USA — 7,190 46,746 — 7,190 46,746 53,936 (1,705) 2021 1/20/2006 Project EX (O) Confidential-USA — 13,010 19,107 — 13,010 19,107 32,117 (1,697) 2018 7/16/2008 PS A (O) Northern Virginia — 4,078 8,808 — 4,078 8,808 12,886 — (7) 1/27/2005 PS B (O) Northern Virginia — 3,468 4,407 — 3,468 4,407 7,875 — (7) 1/27/2005 Redstone Gateway (L) Huntsville, AL — — 25,386 — — 25,386 25,386 — (6) 3/23/2010 Sentry Gateway - T (O) San Antonio, TX — 14,020 38,804 13 14,020 38,817 52,837 (15,413) 1982/2008 3/30/2005 Sentry Gateway - V (O) San Antonio, TX — — 1,066 — — 1,066 1,066 (374) 2007 3/30/2005 Sentry Gateway - W (O) San Antonio, TX — — 1,884 71 — 1,955 1,955 (651) 2009 3/30/2005 Sentry Gateway - X (O) San Antonio, TX — 1,964 21,178 — 1,964 21,178 23,142 (6,434) 2010 1/20/2006 Sentry Gateway - Y (O) San Antonio, TX — 1,964 21,298 — 1,964 21,298 23,262 (6,472) 2010 1/20/2006 Sentry Gateway - Z (O) San Antonio, TX — 1,964 30,573 — 1,964 30,573 32,537 (5,968) 2015 6/14/2005 SP Manassas (L) Manassas, VA — 8,156 921 — 8,156 921 9,077 — (6) 7/24/2019 Westfields - Park Center (L) Chantilly, VA — 8,667 3,170 — 8,667 3,170 11,837 — (6) 7/2/2013 Other Developments, including Various — — 1,169 258 — 1,427 1,427 (135) Various Various $ 118,293 $ 709,752 $ 3,606,680 $ 670,105 $ 709,752 $ 4,276,785 $ 4,986,537 $ (1,273,448) (1) A legend for the Property Type follows: (O) = Office or data center shell property; (L) = Land held or pre-development; and (V) = Various. (2) Excludes our Revolving Credit Facility of $211.0 million, term loan facilities of $123.9 million, unsecured senior notes of $1.8 billion, unsecured notes payable of $597,000, and deferred financing costs, net of premiums, on the remaining loans of $541,000. (3) The aggregate cost of these assets for federal income tax purposes was approximately $3.7 billion as of December 31, 2022. (4) The estimated lives over which depreciation is recognized follow: Building and land improvements: 10-40 years; and tenant improvements: related lease terms. (5) The acquisition date of multi-parcel properties reflects the date of the earliest parcel acquisition. The acquisition date of properties owned through real estate joint ventures reflects the date of the formation of the joint venture. (6) Held as of December 31, 2022. (7) Under development as of December 31, 2022. (8) Classified as held for sale as of December 31, 2022. The following table summarizes our changes in cost of properties for the years ended December 31, 2022, 2021 and 2020 (in thousands): 2022 2021 2020 Beginning balance $ 4,959,709 $ 4,686,802 $ 4,348,006 Improvements and other additions 350,702 342,684 405,940 Sales (1) (323,874) (103,097) (65,475) Impairments — — (1,530) Other dispositions — (4,511) (139) Reclassification from right-of-use asset — 37,831 — Ending balance $ 4,986,537 $ 4,959,709 $ 4,686,802 The following table summarizes our changes in accumulated depreciation for the same time periods (in thousands): 2022 2021 2020 Beginning balance $ 1,234,908 $ 1,124,253 $ 1,007,120 Depreciation expense 124,803 130,604 119,377 Sales (1) (86,263) (15,438) (2,105) Other dispositions — (4,511) (139) Ending balance $ 1,273,448 $ 1,234,908 $ 1,124,253 (1) Includes sales of our wholesale data center and ownership interests in data center shells through newly-formed unconsolidated real estate joint ventures, as described in Note 4 to our consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These consolidated financial statements include the accounts of COPT, the Operating Partnership, their subsidiaries and other entities in which COPT has a majority voting interest and control. We also consolidate certain entities when control of such entities can be achieved through means other than voting rights (“variable interest entities” or “VIEs”) if we are deemed to be the primary beneficiary of such entities. We eliminate all intercompany balances and transactions in consolidation. We use the equity method of accounting when we own an interest in an entity and can exert significant influence over but cannot control the entity’s operations. We discontinue equity method accounting if our investment in an entity (and net advances) is reduced to zero unless we have guaranteed obligations of the entity or are otherwise committed to provide further financial support for the entity.
Reclassifications	Reclassifications We reclassified certain amounts from prior periods to conform to the current period presentation of our consolidated financial statements with no effect on previously reported net income or equity.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements We make estimates and assumptions when preparing financial statements under generally accepted accounting principles (“GAAP”). These estimates and assumptions affect various matters, including: • the reported amounts of assets and liabilities in our consolidated balance sheets as of the dates of the financial statements; • the disclosure of contingent assets and liabilities as of the dates of the financial statements; and • the reported amounts of revenues and expenses in our consolidated statements of operations during the reporting periods.
Properties	Properties We report properties to be developed or held and used in operations at our depreciated cost, reduced for impairment losses. We capitalize direct and indirect project costs (including related compensation and other indirect costs), interest expense and real estate taxes associated with properties, or portions thereof, undergoing development or redevelopment activities. In capitalizing interest expense, if there is a specific borrowing for a property undergoing development or redevelopment activities, we apply the interest rate of that borrowing to the average accumulated expenditures that do not exceed such borrowing; for the portion of expenditures exceeding any such specific borrowing, we apply our weighted average interest rate on other borrowings to the expenditures. We continue to capitalize costs while development or redevelopment activities are underway until a property becomes “operational,” which occurs when lease terms commence (generally when the tenant has control of the leased space and we have delivered the premises to the tenant as required under the terms of such lease), but no later than one year after the cessation of major construction activities. When leases commence on portions of a newly-developed or redeveloped property in the period prior to one year from the cessation of major construction activities, we consider that property to be “partially operational.” When a property is partially operational, we allocate the costs associated with the property between the portion that is operational and the portion under development. We start depreciating costs associated with newly-developed or redeveloped properties as they become operational. For newly-developed properties, we classify improvements provided under the terms of a lease that are deemed to be landlord assets (as discussed further below) as new building development costs. Most of our leases provide for some form of improvements to leased space. When we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets. If the improvements are landlord assets, we capitalize the cost of the improvements and recognize depreciation expense over the estimated useful lives of the assets as discussed below. We recognize any payments from the tenant for such assets as lease revenue over the term of the lease. If the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset and amortize it as a reduction of rental revenue over the term of the lease. In determining whether improvements constitute landlord or tenant assets, we consider numerous factors, including whether the economic substance of the lease terms is properly reflected and whether the improvements: have value to us as real estate; are unique to the tenant or reusable by other tenants; may be altered or removed by the tenant without our consent or without compensating us for any lost fair value; or are owned, and remain, with us or the tenant at the end of the lease term. We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years We report properties disposed or classified as held for sale as discontinued operations when the disposition represents a strategic shift having a major effect on our operations and financial results (such as a disposition of a reportable segment or subsegment or major line of business). For discontinued operations, we classify for all periods presented the associated: assets as held for sale on our consolidated balance sheets; and results of operations as discontinued operations on our consolidated statements of operations (including interest expense on debt specifically identifiable to such components). For periods in which a property not reported as discontinued operations is classified as held for sale, we classify the assets of the property’s asset group as held for sale on our consolidated balance sheets.
Sale of Properties	Sales of PropertiesWe recognize gains from sales of consolidated interests in properties when we transfer control of such interests.
Impairment of Properties	Impairment of Properties We assess the asset groups associated with each of our properties, including operating properties, properties in development, land held for future development, related intangible assets, right-of-use assets, deferred rents receivable and lease liabilities, for indicators of impairment quarterly or when circumstances indicate that an asset group may be impaired. If our analyses indicate that the carrying values of certain properties’ asset groups may be impaired, we perform a recovery analysis for such asset groups. For properties to be held and used, we analyze recoverability based on the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over, in most cases, a ten-year holding period. If we believe it is more likely than not that we will dispose of the properties earlier, we analyze recoverability using a probability weighted analysis of the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over the various possible holding periods. If the analysis indicates that the carrying value of a tested property’s asset group is not recoverable from its estimated future cash flows, the property’s asset group is written down to the property’s estimated fair value and an impairment loss is recognized. If and when our plans change, we revise our recoverability analyses to use the cash flows expected from the operations and eventual disposition of such property using holding periods that are consistent with our revised plans; as a result, changes in holding periods may require us to recognize impairment losses. Fair values are estimated based on contract prices, indicative bids, discounted cash flow analyses, yield analyses or comparable sales analyses. Estimated cash flows used in our impairment analyses are based on our plans for the property and our views of market and economic conditions. The estimates consider items such as current and future market rental and occupancy rates, estimated operating and capital expenditures and recent sales data for comparable properties; most of these items are influenced by market data obtained from real estate leasing and brokerage firms and our direct experience with the properties and their markets.
Acquisition of Operating Properties	Acquisition of Operating Properties Upon completion of operating property acquisitions, we allocate the purchase price to tangible and intangible assets and liabilities associated with such acquisitions based on our estimates of their fair values. We determine these fair values by using market data and independent appraisals available to us and making numerous estimates and assumptions. We allocate operating property acquisitions to the following components: • properties based on a valuation performed under the assumption that the property is vacant upon acquisition (the “if-vacant value”). The if-vacant value is allocated based on the valuation performed between land and buildings or, in the case of properties under development, development in progress. We also allocate additional amounts to properties for in-place tenant improvements based on our estimate of improvements per square foot provided under market leases that would be attributable to the remaining non-cancelable terms of the respective leases; • above- and below-market lease intangible assets or liabilities based on the present value (using an estimated interest rate reflective of the risks associated with the leases acquired) of the difference between: (1) the contractual amounts to be received pursuant to the in-place leases; and (2) our estimate of fair market lease rates for the corresponding spaces, measured over a period equal to the remaining non-cancelable terms of the respective leases. The capitalized above- and below-market lease values are amortized as adjustments to lease revenue over the remaining lease terms of the respective leases, and to renewal periods in the case of below-market leases; • in-place lease value based on our estimates of: (1) the present value of additional income to be realized as a result of leases being in place on the acquired properties; and (2) costs to execute similar leases. Our estimate of costs to execute similar leases includes leasing commissions, legal and other related costs; • tenant relationship value based on our evaluation of the specific characteristics of each tenant’s lease and our overall relationship with that respective tenant. Characteristics we consider in determining these values include the nature and extent of our existing business relationships with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals, among other factors; and • above- and below-market cost arrangements (such as real estate tax treaties or above- or below-market ground leases) based on the present value of the expected benefit from any such arrangements in place on the property at the time of acquisition.
Leased Assets, as a Lessee	Leased Assets, as a LesseeWe recognize right-of-use assets and lease liabilities for land and other assets leased by us from third parties for terms of at least one year. We recognize lease expense over lease terms on a straight-line basis for operating leases and on an effective interest method basis for finance leases. In determining right-of-use assets and lease liabilities, we estimate an appropriate incremental borrowing rate on a fully-collateralized basis for the terms of the leases. Since the terms under our land leases are usually significantly longer than the terms of borrowings available to us on a fully-collateralized basis, our estimates of rates for such leases require significant judgment, and consider factors such as estimated interest rates available to us on a fully-collateralized basis for shorter-termed debt and U.S. Treasury rates.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include all cash and liquid investments that mature three months or less from when they are purchased. Cash equivalents are reported at cost, which approximates fair value. We maintain our cash in bank accounts in amounts that may exceed federally insured limits at times. We have not experienced any losses on these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions.
Investments in Marketable Securities	Investments in Marketable SecuritiesWe classify marketable securities as trading securities when we have the intent to sell such securities in the near term, and classify other marketable securities as available-for-sale securities. We determine the appropriate classification of investments in marketable securities at the acquisition date and re-evaluate the classification at each balance sheet date. We report investments in marketable securities classified as trading securities at fair value (which is included in the line entitled “Prepaid expenses and other assets, net” on our consolidated balance sheets), with unrealized gains and losses recognized through earnings; on our consolidated statements of cash flows, we classify cash flows from these securities as operating activities.
Receivables and Credit Losses	Receivables and Credit Losses We write off receivables when we believe the facts and circumstances indicate that continued pursuit of collection is no longer warranted. When cash is received in connection with receivables for which we have previously recognized credit losses, we recognize reductions in our credit losses. Lease Revenue We estimate the collectability of lease revenue and related accounts receivable using judgement based on the credit status and payment history of the related tenants. If we deem that collectability of revenue under a lease is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. Financial Assets and Other Instruments Effective January 1, 2020, we adopted guidance issued by the Financial Accounting Standards Board (“FASB”) that changed how we measure credit losses for most financial assets and certain other instruments not measured at fair value through net income from an incurred loss model to an expected loss approach. We adopted this guidance using the modified retrospective transition method under which we recognized a $5.5 million allowance for credit losses by means of a cumulative-effect adjustment to cumulative distributions in excess of net income and did not adjust prior comparative reporting periods. Our items within the scope of this guidance include: • investing receivables, as disclosed in Note 8; • tenant notes receivable; • net investment in sales-type leases; • other assets comprised of non-lease revenue related accounts receivable (primarily from construction contract services) and contract assets from unbilled construction contract revenue; and • off-balance sheet credit exposures. Under this guidance, we recognize an estimate of our expected credit losses on these items as an allowance, as the guidance requires that financial assets be measured on an amortized cost basis and be presented at the net amount expected to be collected (or as a separate liability in the case of off-balance sheet credit exposures). The allowance represents the portion of the amortized cost basis that we do not expect to collect (or loss we expect to incur in the case of off-balance sheet credit exposures) due to credit over the contractual life based on available information relevant to assessing the collectability of cash flows, which includes consideration of past events, current conditions and reasonable and supportable forecasts of future economic conditions (including consideration of asset- or borrower-specific factors). The allowance for expected credit losses reflects the risk of loss, even when that risk is remote. An allowance for credit losses is measured and recorded upon the initial recognition of a financial asset (or off-balance sheet credit exposure), regardless of whether it is originated or purchased. Quarterly, the expected losses are re-estimated, considering any cash receipts and changes in risks or assumptions, with resulting adjustments recognized as credit loss expense or recoveries on our consolidated statements of operations. We estimate expected credit losses for items within the scope of this guidance using historical loss rate information developed for varying classifications of credit risk and contractual lives. Due to our limited quantity of items within the scope of this guidance and the unique risk characteristics of such items, we individually assign each in-scope item a credit risk classification. The credit risk classifications assigned by us are determined based on credit ratings assigned by ratings agencies (as available) or are internally-developed based on available financial information, historical payment experience, credit documentation, other publicly available information and current economic trends. In addition, for certain items in which the risk of credit loss is affected by the economic performance of a real estate development project, we develop probability weighted scenario analyses for varying levels of performance in estimating our credit loss allowance (applicable to our notes receivable from the City of Huntsville disclosed in Note 8 and a tax incremental financing obligation disclosed in Note 19).
Deferred Leasing and Deferred Financing Costs	Deferred Leasing CostsWe defer costs incurred to obtain new tenant leases or extend existing tenant leases. We amortize these costs evenly over the lease terms. We classify leasing costs paid as an investing activity on our statements of cash flows since such costs are necessary in order for us to generate long-term future cash flows from our properties. When tenant leases are terminated early, we expense any unamortized deferred leasing costs associated with those leases over the shortened lease term. Deferred Financing Costs We defer costs of financing arrangements and recognize these costs as interest expense over the related debt terms on a straight-line basis, which approximates the amortization that would occur under the effective interest method of amortization. We expense any unamortized loan costs when loans are retired early or significantly modified. We present deferred costs of financing arrangements as a direct deduction from the related debt liability, except for costs attributable to line-of-credit arrangements and interest rate derivatives, which we present in the balance sheet in the line entitled “prepaid expenses and other assets, net”.
Intangible Assets and Deferred Revenue on Property Acquisitions	Intangible Assets and Deferred Revenue on Property Acquisitions We amortize intangible assets and deferred revenue on property acquisitions as follows: Asset Type Amortization Period Statement of Operations Location Above- and below-market leases Related lease terms Lease revenue In-place lease value Related lease terms Depreciation and amortization associated with real estate operations Tenant relationship value Estimated period of time that tenant will lease space in property Depreciation and amortization associated with real estate operations
Interest Rate Derivatives	Interest Rate Derivatives Our primary objectives in using interest rate derivatives are to add stability to interest expense and to manage exposure to interest rate movements. To accomplish this objective, we use interest rate swaps as part of our interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for our making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. We use interest rate swaps to hedge the cash flows associated with interest rates on variable-rate debt borrowings. We have also used forward-starting interest rate swaps to hedge the cash flows associated with interest rates on forecasted fixed-rate borrowings. We recognize all derivatives as assets or liabilities on our consolidated balance sheet at fair value.
Noncontrolling Interests	Noncontrolling InterestsOur consolidated noncontrolling interests are comprised of interests in COPLP not owned by COPT and interests in consolidated real estate joint ventures not owned by us (discussed further in Note 6). We evaluate whether noncontrolling interests are subject to redemption features outside of our control. We classify noncontrolling interests that are currently redeemable for cash at the option of the holders or are probable of becoming redeemable as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets; we adjust these interests each period to the greater of their fair value or carrying amount (initial amount as adjusted for allocations of income and losses and contributions and distributions), with a corresponding offset to additional paid-in capital on our consolidated balance sheets. Our other noncontrolling interests are reported in the equity section of our consolidated balance sheets.
Revenue Recognition	Revenue Recognition Lease and Other Property Revenue We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases usually include options under which the tenant may renew its lease based on market rates at the time of renewal, which are then typically subject to further negotiation. These leases occasionally provide the tenant with an option to terminate its lease early usually for a defined termination fee. Most of our lease revenue is from fixed contractual payments defined under the lease that, in most cases, escalate annually over the term of the lease. Our lease revenue also includes variable lease payments predominantly for tenant reimbursements of property operating expenses and lease termination fees. Property operating expense reimbursement structures vary, with some tenants responsible for all of a property’s expenses, while others are responsible for their share of a property’s expense only to the extent such expenses exceed amounts defined in the lease (which are derived from the property’s historical expense levels). Lease termination fees in most cases result from a tenant’s exercise of an existing right under a lease. Upon lease commencement, we evaluate leases to determine if they meet criteria set forth in lease accounting guidance for classification as sales-type leases or direct financing leases; if a lease meets none of these criteria, we classify the lease as an operating lease. Upon commencement of sales-type leases, we derecognize the underlying asset, recognizing in its place a net investment in the lease equal to the sum of the lease receivable and the present value of any unguaranteed residual asset and recognize any selling profit or loss created as a result of the difference between those two amounts. Similarly, for direct financing leases, we would derecognize the underlying asset and recognize a net investment in the lease, but, unlike in a sales-type lease, would defer profit and amortize it as interest income over the lease term. Our leases of properties as lessor are predominantly classified as operating leases, for which the underlying asset remains on our balance sheet and is depreciated consistently with other owned assets, with income recognized as described below. We recognize minimum rents on operating leases, net of abatements, on a straight-line basis over the term of tenant leases. A lease term commences when: (1) the tenant has control of the leased space (legal right to use the property); and (2) we have delivered the premises to the tenant as required under the terms of the lease. The term of a lease includes the noncancellable periods of the lease along with periods covered by: (1) a tenant option to extend the lease if the tenant is reasonably certain to exercise that option; (2) a tenant option to terminate the lease if the tenant is reasonably certain not to exercise that option; and (3) an option to extend (or not to terminate) the lease in which exercise of the option is controlled by us as the lessor. When assessing the expected lease end date, we use judgment in contemplating the significance of: any penalties a tenant may incur should it choose not to exercise any existing options to extend the lease or exercise any existing options to terminate the lease; and economic incentives for the tenant based on any existing contract, asset, entity or market-based factors in the lease. While a significant portion of our portfolio is leased to the USG, and the majority of those leases consist of a series of one-year renewal options, or provide for early termination rights, we have concluded that exercise of existing renewal options, or continuation of such leases without exercising early termination rights, is reasonably certain for most of these leases. We elected a practical expedient available under lease accounting guidance that enables us to combine non-lease components that otherwise would need to be accounted for under revenue accounting guidance (such as tenant reimbursements of property operating expenses) with the associated lease components for our accounting and reporting of operating lease revenue. We report the amount by which our minimum rental revenue recognized on a straight-line basis under leases exceeds the contractual rent billings associated with such leases as deferred rent receivable on our consolidated balance sheets. Amounts by which our minimum rental revenue recognized on a straight-line basis under leases are less than the contractual rent billings associated with such leases are reported in liabilities as deferred revenue associated with operating leases on our consolidated balance sheets. In connection with a tenant’s entry into, or modification of, a lease, if we make cash payments to, or on behalf of, the tenant for purposes other than funding the construction of landlord assets, we generally defer the amount of such payments as lease incentives. As discussed above, when we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets; if the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset. We amortize lease incentives as a reduction of rental revenue over the term of the lease. If collectability under a lease is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. We recognize lease revenue associated with tenant expense recoveries in the same periods in which we incur the related expenses, including tenant reimbursements of property taxes, utilities and other property operating expenses. We recognize fees received for lease terminations as revenue and write off against such revenue any (1) deferred rents receivable, and (2) deferred revenue, lease incentives and intangible assets that are amortizable into lease revenue associated with such leases; the resulting net amount is the net revenue from the early termination of the leases. When a tenant’s lease for space in a property is terminated early but the tenant continues to lease such space under a new or modified lease in the property, the net revenue from the early termination of the lease is recognized evenly over the remaining life of the new or modified lease in place on that property. Construction Contract and Other Service Revenues We enter into construction contracts to complete various design and construction services primarily for our USG tenants. The revenues and expenses from these services consist primarily of subcontracted costs that are reimbursed to us by our customers along with a fee. These services are an ancillary component of our overall operations, with small operating margins relative to the revenue. We review each contract to determine the performance obligations and allocate the transaction price based on the standalone selling price, as discussed further below. We recognize revenue under these contracts as services are performed in an amount that reflects the consideration we expect to receive in exchange for those services. Our performance obligations are satisfied over time as work progresses. Revenue recognition is determined using the input method based on costs incurred as of a point in time relative to the total estimated costs at completion to measure progress toward satisfying our performance obligations. We believe incurred costs of work performed best depicts the transfer of control of the services being transferred to the customer. In determining whether the performance obligations associated with a construction contract should be accounted for separately versus together, we consider numerous factors that may require significant judgment, including: whether the components contracted are substantially the same with the same pattern of transfer; whether the customer could contract with another party to perform construction based on our design project; and whether the customer can elect not to move forward after the design phase of the contract. Most of our contracts have a single performance obligation as the promise to transfer the services is not separately identifiable from other obligations in the contracts and, therefore, are not distinct. Some contracts have multiple performance obligations, most commonly due to having distinct project phases for design and construction that our customer is managing separately. In these cases, we allocate the transaction price between these performance obligations based on the relative standalone selling prices, which we determine by evaluating: the relative costs of each performance obligation; the expected operating margins (which typically do not vary significantly between obligations); and amounts set forth in the contracts for each obligation. Contract modifications, such as change orders, are routine for our construction contracts and are generally determined to be additions to the existing performance obligations because they would have been part of the initial performance obligations if they were identified at the initial contract date. We have three main types of compensation arrangements for our construction contracts: guaranteed maximum price (“GMP”); firm fixed price (“FFP”); and cost-plus fee. • GMP contracts provide for revenue equal to costs incurred plus a fee equal to a percentage of such costs, up to a maximum contract amount. We generally enter into GMP contracts for projects that are significant in nature based on the size of the project and total fees and with an undefined scope as of the contract date. GMP contracts are lower risk to us than FFP contracts since the costs and revenue move proportionately to one another. • FFP contracts provide for revenue equal to a fixed fee. These contracts are typically lower in value and scope relative to GMP contracts, and are generally entered into when the scope of the project is well defined. Typically, we assume more risk with FFP contracts than GMP contracts since the revenue is fixed and we could realize losses or less than expected profits if we incur more costs than originally estimated. However, these types of contracts offer the opportunity for additional profits when we complete the work for less than originally estimated. • Cost-plus fee contracts provide for revenue equal to costs incurred plus a fee equal to a percentage of such costs but, unlike GMP contracts, do not have a maximum contract amount. Similar to GMP contracts, cost-plus fee contracts are low risk to us since the costs and revenue move proportionately to one another. Construction contract cost estimates are based primarily on contracts in place with subcontractors to complete most of the work, but may also include assumptions, such as performance of subcontractors and cost and availability of materials, to project the outcome of future events over the course of the project. We review and update these estimates regularly as a significant change could affect the profitability of our construction contracts. We recognize adjustments in estimated profit on contracts under the cumulative catch-up method as the modification does not create a new performance obligation. Under this method, the impact of an adjustment to profit recorded to date on a contract is recognized in the period the adjustment is identified. Revenue and profit in future periods are recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on a contract, we recognize the total loss in the quarter it is identified. Our timing of revenue recognition for construction contracts generally differs from the timing of invoicing to customers. We recognize construction contract revenue as we satisfy our performance obligations. Payment terms and conditions vary by contract type. Under most of our contracts, we bill customers monthly, as work progresses, in accordance with the contract terms, with payment due in 30 days, although customers occasionally pay in advance of services being provided. We have determined that our contracts generally do not include a significant financing component. The timing of our customer invoicing is for convenience purposes, not to provide or receive financing. Additionally, the timing of transfer of our services is often at the discretion of the customer. Under most of our contracts, we bill customers one month subsequent to revenue recognition, resulting in contract assets representing unbilled construction revenue.
Expense Classification	Expense Classification We classify as property operating expenses costs incurred for property taxes, ground rents, utilities, property management, insurance, repairs and exterior and interior maintenance, as well as associated labor and indirect costs. We classify as general, administrative and leasing expenses costs incurred for corporate-level management, public company administration, asset management, leasing, investor relations, marketing, corporate-level insurance and leasing prospects, as well as associated labor and indirect costs.
Share-Based Compensation	Share-Based Compensation We issue four forms of share-based compensation: restricted COPT common shares (“restricted shares”), profit interest units (“PIUs”) (time-based and performance-based), deferred share awards (also known as restricted share units) and performance share units (also known as performance share awards) (“PSUs”). We account for share-based compensation based on the fair value of awards on the grant date; such cost is then recognized over the period during which the employee is required to provide service in exchange for the award. No compensation cost is recognized for equity instruments for which employees do not render the requisite service. The guidance also requires that share-based compensation be computed based on awards that are ultimately expected to vest; as a result, future forfeitures of awards are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. If an award is voluntarily cancelled by an employee, we recognize the previously unrecognized cost associated with the original award on the date of such cancellation. We capitalize costs associated with share-based compensation attributable to employees engaged in development and redevelopment activities.
Income Taxes	Income Taxes COPT elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code. To qualify as a REIT, COPT must meet a number of organizational and operational requirements, including a requirement that it distribute at least 90% of its adjusted taxable income to its shareholders. As a REIT, COPT generally will not be subject to federal income tax on taxable income that it distributes to its shareholders. If COPT fails to qualify as a REIT in any tax year, it will be subject to federal income tax on its taxable income at regular corporate rates and may not be able to qualify as a REIT for four subsequent tax years. For federal income tax purposes, dividends to shareholders may be characterized as ordinary income, capital gains or return of capital. The characterization of dividends paid on COPT’s common shares during each of the last three years was as follows: For the Years Ended December 31, 2022 2021 2020 Ordinary income 68.2 % 33.3 % 45.1 % Long-term capital gain 31.8 % 57.3 % 54.9 % Return of capital — % 9.4 % — % The dividends allocated to each of the above years for federal income tax purposes included dividends paid on COPT’s common shares during each of those years except for the dividends paid on January 15, 2021 and 2020 (with a record date of December 31, 2020 and 2019, respectively), which were allocated for federal income tax purposes to 2020 and 2019, respectively. We distributed all of COPT’s REIT taxable income in 2022, 2021 and 2020 and, as a result, did not incur federal income tax in those years. The net basis of our consolidated assets and liabilities for tax reporting purposes was approximately $7 million lower than the amount reported on our consolidated balance sheet as of December 31, 2022.
Recent Accounting Pronouncements	Recent Accounting PronouncementsIn March 2020, the FASB issued guidance containing practical expedients for reference rate reform related activities pertaining to debt, leases, derivatives and other contracts. The guidance is optional and may be elected over time as reference rate reform activities occur. In 2020, we elected to apply an expedient to treat any changes in loans resulting from reference rate reform as debt modifications (as opposed to extinguishments) and hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of the hedge accounting expedients preserves the presentation of derivatives consistent with past presentation. In addition, in 2022 we entered into bilateral agreements with swap counterparties to transition certain interest rate swap agreements from LIBOR to SOFR; in connection with these amendments, we elected to apply an expedient under this guidance for changes in the critical terms of the hedging relationships due to reference rate reform to not result in a dedesignation of these hedging relationships.
Fair Value Measurement	Accounting standards define fair value as the exit price, or the amount that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. The standards also establish a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of us. Unobservable inputs are inputs that reflect our assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available in the circumstances. The hierarchy of these inputs is broken down into three levels: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs include (1) quoted prices for similar assets or liabilities in active markets, (2) quoted prices for identical or similar assets or liabilities in inactive markets and (3) inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly; and Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is most significant to the fair value measurement.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of the estimated useful lives of fixed assets	We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years Operating properties, net, excluding properties held for sale, consisted of the following (in thousands): December 31, 2022 2021 Land $ 539,809 $ 572,900 Buildings and improvements 3,986,524 3,670,133 Less: Accumulated depreciation (1,267,434) (1,152,523) Operating properties, net $ 3,258,899 $ 3,090,510
Schedule of amortization of intangible assets and deferred revenue	We amortize intangible assets and deferred revenue on property acquisitions as follows: Asset Type Amortization Period Statement of Operations Location Above- and below-market leases Related lease terms Lease revenue In-place lease value Related lease terms Depreciation and amortization associated with real estate operations Tenant relationship value Estimated period of time that tenant will lease space in property Depreciation and amortization associated with real estate operations
Schedule of characterization of dividends declared on common and preferred shares	The characterization of dividends paid on COPT’s common shares during each of the last three years was as follows: For the Years Ended December 31, 2022 2021 2020 Ordinary income 68.2 % 33.3 % 45.1 % Long-term capital gain 31.8 % 57.3 % 54.9 % Return of capital — % 9.4 % — %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis	The table below sets forth our financial assets and liabilities accounted for at fair value on a recurring basis as of December 31, 2022 and 2021 and the hierarchy level of inputs used in measuring their respective fair values under applicable accounting standards (in thousands): Description Quoted Prices in Significant Other Significant Total December 31, 2022: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 1,762 $ — $ — $ 1,762 Other 69 — — 69 Interest rate derivatives (1) — 2,631 — 2,631 Total assets $ 1,831 $ 2,631 $ — $ 4,462 Liabilities: Deferred compensation plan liability (2) $ — $ 1,831 $ — $ 1,831 December 31, 2021: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 2,485 $ — $ — $ 2,485 Other 71 — — 71 Other marketable securities (1) 33 — — 33 Interest rate derivatives (1) — 355 — 355 Total assets $ 2,589 $ 355 $ — $ 2,944 Liabilities: Deferred compensation plan liability (2) $ — $ 2,556 $ — $ 2,556 Interest rate derivatives — 3,644 — 3,644 Total liabilities $ — $ 6,200 $ — $ 6,200 (1) Included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. (2) Included in the line entitled “other liabilities” on our consolidated balance sheets.

Properties, Net (Tables)

Properties, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Real Estate [Abstract]
Schedule of operating properties, net	We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years Operating properties, net, excluding properties held for sale, consisted of the following (in thousands): December 31, 2022 2021 Land $ 539,809 $ 572,900 Buildings and improvements 3,986,524 3,670,133 Less: Accumulated depreciation (1,267,434) (1,152,523) Operating properties, net $ 3,258,899 $ 3,090,510
Disclosure of Long Lived Assets Held-for-sale	The table below sets forth the components of assets classified as held for sale on our consolidated balance sheets (in thousands): December 31, 2022 2021 Properties, net $ 156,691 $ 191,857 Deferred rent receivable 4,595 462 Deferred leasing costs, net — 307 Intangible assets on property acquisitions, net — 73 Assets held for sale, net $ 161,286 $ 192,699
Disposal Groups, Including Discontinued Operations	The table below sets forth the property’s results of operations included in discontinued operations on our consolidated statements of operations and its operating and investing cash flows included on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, 2022 2021 2020 Revenues from real estate operations $ 1,980 $ 30,490 $ 27,011 Property operating expenses (971) (16,842) (13,044) Depreciation and amortization associated with real estate operations — (10,290) (11,690) Gain on sale of real estate 28,564 — — Discontinued operations 29,573 3,358 2,277 Cash flows from operating activities $ 5,757 $ 10,930 $ 16,051 Cash flows from investing activities $ 220,565 $ (1,912) $ (11,485)

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Operating Lease Revenue Recognized	The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2022 2021 2020 Fixed $ 453,907 $ 436,768 $ 404,244 Variable 126,262 116,900 104,870 $ 580,169 $ 553,668 $ 509,114 (1) Excludes lease revenue from discontinued operations of which $1.5 million, $22.3 million and $21.3 million was fixed and $527,000, $8.2 million and $5.7 million was variable for 2022, 2021 and 2020, respectively.
Sales-type leases fixed contractual payments due	Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2022 Year Ending December 31, Operating leases Sales-type leases 2023 $ 443,092 $ 960 2024 415,914 960 2025 336,522 960 2026 269,778 960 2027 236,079 960 Thereafter 1,114,240 2,596 Total contractual payments $ 2,815,625 7,396 Less: Amount representing interest (1,730) Net investment in sales-type leases $ 5,666
Operating leases fixed contractual payments due	Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2022 Year Ending December 31, Operating leases Sales-type leases 2023 $ 443,092 $ 960 2024 415,914 960 2025 336,522 960 2026 269,778 960 2027 236,079 960 Thereafter 1,114,240 2,596 Total contractual payments $ 2,815,625 7,396 Less: Amount representing interest (1,730) Net investment in sales-type leases $ 5,666
Right-of-Use Assets and Lease Liabilities	The table below sets forth our property right-of-use assets and property lease liabilities on our consolidated balance sheets (in thousands): As of December 31, Leases Balance Sheet Location 2022 2021 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 37,020 $ 38,361 Finance leases - Property Prepaid expenses and other assets, net 2,207 2,238 Total right-of-use assets $ 39,227 $ 40,599 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 28,759 $ 29,342
Lease Costs	The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2022 2021 2020 Operating lease cost Property leases - fixed Property operating expenses $ 4,114 $ 4,011 $ 2,413 Property leases - variable Property operating expenses 65 45 127 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 31 34 $ 4,210 $ 4,087 $ 2,574 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2022 2021 2020 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,355 $ 3,206 $ 1,694 Financing cash flows for financing leases $ — $ 14 $ 674
Operating Lease, Liability, Maturity	Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2022 2023 $ 3,399 2024 3,451 2025 1,797 2026 1,578 2027 1,593 Thereafter 124,341 Total lease payments 136,159 Less: Amount representing interest (107,400) Lease liability $ 28,759

Real Estate Joint Ventures (Tab

Real Estate Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2022
Equity Method Investments and Joint Ventures [Abstract]
Schedule of information related to investments in consolidated real estate joint ventures	The table below sets forth information as of December 31, 2022 pertaining to our investments in consolidated real estate joint ventures, which are each variable interest entities (dollars in thousands): Nominal Ownership % December 31, 2022 (1) Date Acquired Total Encumbered Assets Total Liabilities Mortgage Debt Entity Location LW Redstone Company, LLC (2) 3/23/2010 85% Huntsville, Alabama $ 595,565 $ 88,646 $ 118,375 $ 52,014 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 168,819 — 854 — M Square Associates, LLC 6/26/2007 50% College Park, Maryland 100,417 59,401 51,042 49,799 $ 864,801 $ 148,047 $ 170,271 $ 101,813 (1) Excludes amounts eliminated in consolidation. (2) As discussed below, we fund all capital requirements. Our partner receives distributions of the first $1.2 million of annual operating cash flows and we receive the remainder.
Schedule of information related to investments in unconsolidated real estate joint ventures	The table below sets forth information pertaining to our investments in unconsolidated real estate joint ventures accounted for using the equity method of accounting (dollars in thousands): Date Acquired Nominal Ownership % Number of Properties Carrying Value of Investment as of December 31, Entity 2022 (1) 2021 BREIT COPT DC JV LLC 6/20/2019 10% 9 $ 11,568 $ 12,460 Quark 12/14/2022 10% 2 6,758 — BRE-COPT 3 6/2/2021 10% 2 3,134 11,850 BRE-COPT 2 (2) 10/30/2020 10% 8 (1,459) 15,579 21 $ 20,001 $ 39,889 (1) Included $21.5 million reported in “Investment in unconsolidated real estate joint ventures” and $1.5 million for investments with deficit balances reported in “other liabilities” on our consolidated balance sheet. (2) Our investment in BRE-COPT 2 was lower than our share of the joint venture’s equity by $7.0 million as of December 31, 2022 and $7.2 million as of December 31, 2021 due to a difference between our cost basis and our share of the joint venture’s underlying equity in its net assets. We recognize adjustments to our share of the joint venture’s earnings and losses resulting from this basis difference in the underlying assets of the joint venture.

Intangible Assets on Property_2

Intangible Assets on Property Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2022
Intangible Assets on Property Acquisitions
Schedule of intangible assets on real estate acquisitions	Intangible assets on property acquisitions consisted of the following (in thousands): December 31, 2022 December 31, 2021 Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net In-place lease value $ 125,207 $ 120,178 $ 5,029 $ 125,591 $ 118,983 $ 6,608 Tenant relationship value 57,210 52,803 4,407 58,082 50,701 7,381 Above-market leases 13,718 13,476 242 13,718 13,435 283 Other 1,333 1,052 281 1,333 1,038 295 $ 197,468 $ 187,509 $ 9,959 $ 198,724 $ 184,157 $ 14,567

Investing Receivables (Tables)

Investing Receivables (Tables)	12 Months Ended
	Dec. 31, 2022
Receivables [Abstract]
Schedule of Investing Receivables	Investing receivables consisted of the following (in thousands): December 31, 2022 2021 Notes receivable from the City of Huntsville $ 69,703 $ 77,784 Other investing loans receivable 17,712 6,041 Amortized cost basis 87,415 83,825 Allowance for credit losses (2,794) (1,599) Investing receivables, net $ 84,621 $ 82,226

Prepaid Expenses and Other As_2

Prepaid Expenses and Other Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Prepaid Expense and Other Assets [Abstract]
Schedule of prepaid expenses and other assets	Prepaid expenses and other assets, net consisted of the following (in thousands): December 31, 2022 2021 Construction contract costs in excess of billings, net $ 22,331 $ 22,384 Prepaid expenses 21,058 20,058 Furniture, fixtures and equipment, net 8,286 9,599 Non-real estate equity investments 5,974 5,544 Net investment in sales-type leases 5,666 6,194 Deferred financing costs, net (1) 5,210 1,314 Deposits 4,616 3,910 Restricted cash 4,172 4,054 Interest rate derivatives 2,631 355 Property - finance right-of-use assets 2,207 2,238 Marketable securities in deferred compensation plan 1,831 2,556 Deferred tax asset, net 1,405 1,841 Other assets 1,230 1,443 Prepaid expenses and other assets, net $ 86,617 $ 81,490 (1) Represents deferred costs, net of accumulated amortization, attributable to our Revolving Credit Facility and interest rate derivatives .
Schedule of tax effects of temporary differences and carry forwards in net deferred tax assets	Deferred tax asset, net reported above includes the following tax effects of temporary differences and carry forwards of our TRS (in thousands): December 31, 2022 2021 Operating loss carry forward $ 1,533 $ 1,835 Property (128) 30 Valuation allowance — (24) Deferred tax asset, net $ 1,405 $ 1,841

Debt, Net (Tables)

Debt, Net (Tables)	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Schedule of debt	Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of December 31, December 31, 2022 2022 2021 Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed rate mortgage debt $ 84,433 $ 86,960 3.82% - 4.62% (2) 2023-2026 Variable rate secured debt 33,318 33,667 SOFR + 0.10% + 1.45% to 1.55% (3) 2025-2026 Total mortgage and other secured debt 117,751 120,627 Revolving Credit Facility (4) 211,000 76,000 SOFR + 0.10% + 0.725% to 1.400% (5) October 2026 Term Loan Facilities (4) 123,948 299,420 SOFR + 0.10% + 0.850% to 1.700% (6) January 2026 Unsecured Senior Notes (4) 2.25%, $400,000 aggregate principal 396,539 395,491 2.25% (7) March 2026 2.00%, $400,000 aggregate principal 396,988 396,512 2.00% (8) January 2029 2.75%, $600,000 aggregate principal 590,123 589,060 2.75% (9) April 2031 2.90%, $400,000 aggregate principal 394,848 394,441 2.90% (10) December 2033 Unsecured note payable 597 753 0% (11) May 2026 Total debt, net $ 2,231,794 $ 2,272,304 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $5.4 million as of December 31, 2022 and $5.8 million as of December 31, 2021. (2) The weighted average interest rate on our fixed rate mortgage debt was 4.07% as of December 31, 2022. (3) The weighted average interest rate on our variable rate secured debt as of December 31, 2022 was 5.58%, or 2.45% including the effect of interest rate swaps that hedge the risk of interest rate changes on this debt. (4) Refer to the paragraphs below for further disclosure. (5) The weighted average interest rate on the Revolving Credit Facility was 5.47% as of December 31, 2022. (6) The interest rate on this loan was 5.72% as of December 31, 2022. (7) The carrying value of these notes reflects an unamortized discount totaling $2.8 million as of December 31, 2022 and $3.6 million as of December 31, 2021 The effective interest rate under the notes, including amortization of the issuance costs, was 2.48%. (8) The carrying value of these notes reflects an unamortized discount totaling $2.1 million as of December 31, 2022 and $2.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.09%. (9) The carrying value of these notes reflects an unamortized discount totaling $8.5 million as of December 31, 2022 and $9.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.94%. (10) The carrying value of these notes reflects an unamortized discount totaling $4.2 million as of December 31, 2022 and $4.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 3.01%. (11) This note carries an interest rate that, upon assumption, was below market rates and it therefore was recorded at its fair value based on applicable effective interest rates. The carrying value of this note reflects an unamortized discount totaling $65,000 as of December 31, 2022 and $108,000 as of December 31, 2021.
Schedule of debt maturities	Our debt matures on the following schedule (in thousands): Year Ending December 31, December 31, 2022 2023 $ 18,954 2024 29,983 2025 23,717 2026 782,300 2027 — Thereafter 1,400,000 Total $ 2,254,954 (1) (1) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $23.2 million.
Schedule of the fair value of debt	The following table sets forth information pertaining to the fair value of our debt (in thousands): December 31, 2022 December 31, 2021 Carrying Estimated Carrying Estimated Fixed-rate debt Unsecured Senior Notes $ 1,778,498 $ 1,433,561 $ 1,775,504 $ 1,809,950 Other fixed-rate debt 85,030 80,330 87,713 87,339 Variable-rate debt 368,266 367,896 409,087 409,639 $ 2,231,794 $ 1,881,787 $ 2,272,304 $ 2,306,928

Interest Rate Derivatives (Tabl

Interest Rate Derivatives (Tables)	12 Months Ended
	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of key terms and fair values of interest rate swap derivatives	The following table sets forth the key terms and fair values of our interest rate swap derivatives (dollars in thousands): Notional Amount Effective Date Expiration Date Fair Value at December 31, Fixed Rate Floating Rate Index 2022 2021 $ 10,880 (1) 1.678 % SOFR plus 0.10% 8/1/2019 8/1/2026 $ 806 $ (234) $ 22,775 (2) 0.573 % SOFR plus 0.10% 4/1/2020 3/26/2025 1,825 355 $ 100,000 1.901 % One-Month LIBOR 9/1/2016 12/1/2022 — (1,361) $ 100,000 1.905 % One-Month LIBOR 9/1/2016 12/1/2022 — (1,365) $ 50,000 (3) 1.908 % One-Month LIBOR 9/1/2016 N/A — (684) $ 2,631 $ (3,289) (1) The notional amount of this instrument is scheduled to amortize to $10.0 million. Effective December 1, 2022, we amended this swap to change the floating rate index from one-month LIBOR to SOFR plus 0.10%. We made elections under reference rate reform related accounting guidance to not result in a dedesignation of this hedging relationship. (2) The notional amount of this instrument is scheduled to amortize to $22.1 million. Effective December 1, 2022, we amended this swap to change the floating rate index from one-month LIBOR to SOFR plus 0.10%. We made elections under reference rate reform related accounting guidance to not result in a dedesignation of this hedging relationship. (3) We cash settled this swap and accrued interest thereon for $625,000 on January 28, 2022.
Schedule of fair value and balance sheet classification of interest rate derivatives	The table below sets forth the fair value of our interest rate derivatives as well as their classification on our consolidated balance sheets (in thousands): Fair Value at December 31, Derivatives Balance Sheet Location 2022 2021 Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 2,631 $ 355 Interest rate swaps designated as cash flow hedges Other liabilities $ — $ (2,960) Interest rate swap not designated Other liabilities $ — $ (684)
Schedule of effect of interest rate derivatives on consolidated statements of operations and comprehensive income	The tables below present the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of Income (Loss) Recognized in AOCI/AOCL on Derivatives Amount of Loss Reclassified from AOCI/AOCL into Interest Expense on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2022 2021 2020 2022 2021 2020 Interest rate derivatives $ 4,730 $ 1,379 $ (39,454) $ (996) $ (5,048) $ (3,725) Amount of Loss Reclassified from AOCL into Loss on Interest Rate Derivatives on Statement of Operations Amount of Loss Recognized on Undesignated Swaps in Loss on Interest Rate Derivatives on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2022 2021 2020 2022 2021 2020 Interest rate derivatives $ — $ — $ (51,865) $ — $ — $ (1,265)

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2022
Noncontrolling Interest [Abstract]
Schedule of activity for redeemable noncontrolling interest	The table below sets forth the activity for these redeemable noncontrolling interests (in thousands): For the Years Ended December 31, 2022 2021 2020 Beginning balance $ 26,898 $ 25,430 $ 29,431 Distributions to noncontrolling interests (2,976) (3,307) (14,034) Net income attributable to noncontrolling interests 2,807 3,160 3,426 Adjustment to arrive at fair value of interests (436) 1,615 6,607 Ending balance $ 26,293 $ 26,898 $ 25,430

Share-Based Compensation and _2

Share-Based Compensation and Other Compensation Matters (Tables)	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Reporting for share-based compensation expense	The table below sets forth our reporting for share based compensation cost (in thousands): For the Years Ended December 31, 2022 2021 2020 General, administrative and leasing expenses $ 7,643 $ 6,881 $ 5,385 Property operating expenses 1,147 1,098 1,119 Capitalized to development activities 847 719 556 Share-based compensation cost $ 9,637 $ 8,698 $ 7,060
Summary of restricted share and TB-PIU transactions under the entity's share-based compensation plans	The following table summarizes restricted shares under the share-based compensation plans for 2020, 2021 and 2022: Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2019 392,863 $ 27.49 Granted 166,918 $ 25.22 Forfeited (25,773) $ 27.12 Vested (173,191) $ 28.14 Unvested as of December 31, 2020 360,817 $ 26.16 Granted 177,995 $ 26.17 Forfeited (39,664) $ 26.62 Vested (164,575) $ 25.95 Unvested as of December 31, 2021 334,573 $ 26.22 Granted 186,515 $ 26.50 Forfeited (43,420) $ 26.47 Vested (152,585) $ 26.39 Unvested as of December 31, 2022 325,083 $ 26.27 Unvested shares as of December 31, 2022 that are expected to vest 297,282 $ 26.25 2022 : Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2019 61,820 $ 26.01 Granted 98,318 $ 25.47 Forfeited (20,622) $ 25.50 Vested (25,182) $ 26.30 Unvested as of December 31, 2020 114,334 $ 25.57 Granted 93,983 $ 26.16 Vested (45,244) $ 25.28 Unvested as of December 31, 2021 163,073 $ 25.99 Granted 101,966 $ 26.39 Vested (77,709) $ 26.04 Unvested as of December 31, 2022 187,330 $ 26.19 Unvested TB-PIUs as of December 31, 2022 that are expected to vest 186,345 $ 26.19
Schedule of PB-PIU's Granted	We made the following grants of PB-PIUs to senior management team members from 2019 through 2022 (dollars in thousands, except per share data): Grant Date Number of PB-PIUs Granted Grant Date Fair Value Number of PB-PIUs Outstanding as of December 31, 2022 1/1/2019 193,682 $ 2,415 — 1/1/2020 176,758 $ 2,891 141,152 1/1/2021 227,544 $ 3,417 227,544 1/1/2022 231,838 $ 3,810 231,838
Schedule of payouts for defined performance under PB-PIU/PSUs	The number of earned awards at the end of the performance period will be determined based on the percentile rank of COPT’s total shareholder return (“TSR”) relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned Awards Payout % 75th or greater 100% of PB-PIUs granted 50th (target) 50% of PB-PIUs granted 25th 25% of PB-PIUs granted Below 25th 0% of PB-PIUs granted The number of PSUs earned (“earned PSUs”) at the end of the performance period were determined based on the percentile rank of COPT’s TSR relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned PSUs Payout % 75th or greater 200% of PSUs granted 50th (target) 100% of PSUs granted 25th 50% of PSUs granted Below 25th 0% of PSUs granted
Schedule of assumptions used in Monte Carlo models for PB-PIUs	The grant date fair value and certain of the assumptions used in the Monte Carlo models for the PB-PIUs granted in 2020, 2021 and 2022 are set forth below: Grant Date Grant Date Fair Value Per PB-PIU at Target-Level Award Baseline Common Share Value Expected Volatility of Common Shares Risk-free Interest Rate 1/1/2020 $ 32.71 $ 29.38 18.0 % 1.65 % 1/1/2021 $ 30.03 $ 26.08 34.7 % 0.18 % 1/1/2022 $ 32.87 $ 27.97 31.7 % 0.98 %
Deferred Shares Granted	We made the following grants of deferred share awards to non-employee Trustees in 2020, 2021 and 2022 (dollars in thousands, except per share data): Year of Grant Number of Deferred Share Awards Granted Aggregate Grant Date Fair Value Grant Date Fair Value Per Award 2020 10,679 $ 253 $ 23.68 2021 3,416 $ 93 $ 27.12 2022 6,771 $ 166 $ 24.50

Information by Business Segme_2

Information by Business Segment (Tables)	12 Months Ended
	Dec. 31, 2022
Segment Reporting [Abstract]
Schedule of segment financial information for real estate operations	The table below reports segment financial information for our reportable segments (in thousands): Defense/IT Locations Fort Meade/BW Corridor NoVA Defense/IT Lackland Air Force Base Navy Support Redstone Arsenal Data Center Shells Total Defense/IT Locations Regional Office Wholesale Other Total Year Ended December 31, 2022 Revenues from real estate operations $ 273,790 $ 73,985 $ 62,911 $ 32,754 $ 38,593 $ 35,722 $ 517,755 $ 59,316 $ 1,980 $ 7,327 $ 586,378 Property operating expenses (97,727) (26,635) (32,301) (14,001) (15,600) (4,372) (190,636) (31,712) (979) (5,074) (228,401) UJV NOI allocable to COPT — — — — — 4,327 4,327 — — — 4,327 NOI from real estate operations $ 176,063 $ 47,350 $ 30,610 $ 18,753 $ 22,993 $ 35,677 $ 331,446 $ 27,604 $ 1,001 $ 2,253 $ 362,304 Additions to long-lived assets $ 48,443 $ 11,102 $ — $ 3,801 $ 3,405 $ — $ 66,751 $ 37,625 $ (35) $ 185 $ 104,526 Transfers from non-operating properties $ 69,771 $ 1,882 $ 1,290 $ 6,420 $ 158,831 $ 179,522 $ 417,716 $ 704 $ — $ — $ 418,420 Segment assets at December 31, 2022 $ 1,387,517 $ 488,277 $ 194,481 $ 169,119 $ 453,543 $ 462,471 $ 3,155,408 $ 550,059 $ — $ 3,804 $ 3,709,271 Year Ended December 31, 2021 Revenues from real estate operations $ 262,120 $ 65,853 $ 57,756 $ 33,757 $ 35,727 $ 31,582 $ 486,795 $ 63,107 $ 30,490 $ 6,668 $ 587,060 Property operating expenses (92,521) (24,785) (30,535) (13,617) (11,618) (4,086) (177,162) (31,056) (17,424) (4,577) (230,219) UJV NOI allocable to COPT — — — — — 4,029 4,029 — — — 4,029 NOI from real estate operations $ 169,599 $ 41,068 $ 27,221 $ 20,140 $ 24,109 $ 31,525 $ 313,662 $ 32,051 $ 13,066 $ 2,091 $ 360,870 Additions to long-lived assets $ 45,647 $ 6,197 $ — $ 4,193 $ 3,542 $ — $ 59,579 $ 35,038 $ 1,680 $ 488 $ 96,785 Transfers from non-operating properties $ 70,514 $ 90,050 $ 59,323 $ — $ 22,739 $ 3,004 $ 245,630 $ 39,319 $ — $ — $ 284,949 Segment assets at December 31, 2021 $ 1,332,399 $ 489,582 $ 198,200 $ 170,985 $ 300,252 $ 350,098 $ 2,841,516 $ 537,268 $ 192,647 $ 4,031 $ 3,575,462 Year Ended December 31, 2020 Revenues from real estate operations $ 254,197 $ 61,685 $ 50,982 $ 32,869 $ 22,515 $ 29,139 $ 451,387 $ 56,759 $ 27,011 $ 3,568 $ 538,725 Property operating expenses (85,032) (22,996) (29,055) (12,655) (8,119) (3,195) (161,052) (27,469) (13,543) (1,776) (203,840) UJV NOI allocable to COPT — — — — — 6,951 6,951 — — — 6,951 NOI from real estate operations $ 169,165 $ 38,689 $ 21,927 $ 20,214 $ 14,396 $ 32,895 $ 297,286 $ 29,290 $ 13,468 $ 1,792 $ 341,836 Additions to long-lived assets $ 31,295 $ 12,314 $ — $ 7,104 $ 2,905 $ — $ 53,618 $ 16,538 $ 10,856 $ 467 $ 81,479 Transfers from non-operating properties $ 21,859 $ 2,557 $ 456 $ — $ 138,122 $ 230,277 $ 393,271 $ 83,091 $ — $ — $ 476,362 Segment assets at December 31, 2020 $ 1,277,849 $ 411,780 $ 142,137 $ 178,897 $ 281,386 $ 419,929 $ 2,711,978 $ 471,356 $ 201,820 $ 3,824 $ 3,388,978
Schedule of reconciliation of segment revenues to total revenues	The following table reconciles our segment revenues to total revenues as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 Segment revenues from real estate operations $ 586,378 $ 587,060 $ 538,725 Construction contract and other service revenues 154,632 107,876 70,640 Less: Revenues from discontinued operations (Note 4) (1,980) (30,490) (27,011) Total revenues $ 739,030 $ 664,446 $ 582,354
Schedule of reconciliation of segment property operating expenses to property operating expenses	The following table reconciles our segment property operating expenses to property operating expenses as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 Segment property operating expenses $ 228,401 $ 230,219 $ 203,840 Less: Property operating expenses from discontinued operations (Note 4) (971) (16,842) (13,044) Total property operating expenses $ 227,430 $ 213,377 $ 190,796
Reconciliation of UJV NOI allocable to COPT to equity in income of unconsolidated entities	The following table reconciles UJV NOI allocable to COPT to equity in income of unconsolidated entities as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 UJV NOI allocable to COPT $ 4,327 $ 4,029 $ 6,951 Less: Income from UJVs allocable to COPT attributable to depreciation and amortization expense, interest expense and gain on extinguishment of debt (3,145) (2,930) (5,120) Add: Equity in income (loss) of unconsolidated non-real estate entities 561 (6) (6) Equity in income of unconsolidated entities $ 1,743 $ 1,093 $ 1,825
Schedule of computation of net operating income from service operations	The table below sets forth the computation of our NOI from service operations (in thousands): For the Years Ended December 31, 2022 2021 2020 Construction contract and other service revenues $ 154,632 $ 107,876 $ 70,640 Construction contract and other service expenses (149,963) (104,053) (67,615) NOI from service operations $ 4,669 $ 3,823 $ 3,025
Schedule of reconciliation of net operating income from real estate operations and service operations to income from continuing operations	The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to income from continuing operations as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2022 2021 2020 NOI from real estate operations $ 362,304 $ 360,870 $ 341,836 NOI from service operations 4,669 3,823 3,025 Depreciation and other amortization associated with real estate operations (141,230) (137,543) (126,503) General, administrative and leasing expenses (35,798) (36,127) (33,001) Business development expenses and land carry costs (3,193) (4,647) (4,473) Impairment losses — — (1,530) Interest expense (61,174) (65,398) (67,937) Interest and other income 9,341 7,879 8,574 Credit loss (expense) recoveries (271) 1,128 933 Gain on sales of real estate 19,250 65,590 30,209 Gain on sale of investment in unconsolidated real estate joint venture — — 29,416 Loss on early extinguishment of debt (609) (100,626) (7,306) Loss on interest rate derivatives — — (53,196) Equity in income of unconsolidated entities 1,743 1,093 1,825 UJV NOI allocable to COPT included in equity in income of unconsolidated entities (4,327) (4,029) (6,951) Income tax expense (447) (145) (353) Revenues from real estate operations from discontinued operations (Note 4) (1,980) (30,490) (27,011) Property operating expenses from discontinued operations (Note 4) 971 16,842 13,044 Income from continuing operations $ 149,249 $ 78,220 $ 100,601
Schedule of reconciliation of segment assets to total assets	The following table reconciles our segment assets to our consolidated total assets (in thousands): As of December 31, 2022 2021 Segment assets $ 3,709,271 $ 3,575,462 Operating properties lease liabilities included in segment assets 28,759 29,342 Non-operating property assets 301,002 449,144 Other assets 218,243 208,504 Total consolidated assets $ 4,257,275 $ 4,262,452

Construction Contract and Oth_2

Construction Contract and Other Service Revenues (Tables)	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The table below reports construction contract and other service revenues by compensation arrangement (in thousands): For the Years Ended December 31, 2022 2021 2020 Construction contract revenue: GMP $ 129,149 $ 68,113 $ 22,032 FFP 15,119 13,897 12,373 Cost-plus fee 8,320 24,260 34,025 Other 2,044 1,606 2,210 $ 154,632 $ 107,876 $ 70,640 The table below reports construction contract and other service revenues by service type (in thousands): For the Years Ended December 31, 2022 2021 2020 Construction contract revenue: Construction $ 151,694 $ 104,020 $ 66,087 Design 894 2,250 2,343 Other 2,044 1,606 2,210 $ 154,632 $ 107,876 $ 70,640
Contract Asset, Contract Liability and Receivable	Accounts receivable related to our construction contract services is included in accounts receivable, net on our consolidated balance sheets. The beginning and ending balances of accounts receivable related to our construction contracts were as follows (in thousands): For the Years Ended December 31, 2022 2021 Beginning balance $ 7,193 $ 13,997 Ending balance $ 7,618 $ 7,193 Contract assets, which we refer to herein as construction contract costs in excess of billings, net, are included in prepaid expenses and other assets, net on our consolidated balance sheets. The beginning and ending balances of our contract assets were as follows (in thousands): For the Years Ended December 31, 2022 2021 Beginning balance $ 22,384 $ 10,343 Ending balance $ 22,331 $ 22,384 Contract liabilities are included in other liabilities on our consolidated balance sheets. Changes in contract liabilities were as follows (in thousands): For the Years Ended December 31, 2022 2021 Beginning balance $ 2,499 $ 4,610 Ending balance $ 2,867 $ 2,499 Portion of beginning balance recognized in revenue during the year $ 278 $ 2,664

Credit Losses on Financial As_2

Credit Losses on Financial Assets and Other Instruments (Tables)	12 Months Ended
	Dec. 31, 2022
Credit Loss [Abstract]
Schedule of Credit Losses, Financial Assets and Other Instruments, Allowance for Credit Loss	The table below sets forth the activity for our allowance for credit losses in 2020, 2021 and 2022 (in thousands): Investing Receivables Tenant Notes Other Assets (2) Off-Balance Sheet Credit Exposures Total December 31, 2019 $ — $ 97 $ — $ — $ 97 Cumulative effect of change for adoption of credit loss guidance 3,732 325 144 1,340 5,541 Credit loss (recoveries) expense (881) 729 559 (1,340) (933) Other changes — 52 (60) — (8) December 31, 2020 2,851 1,203 643 — 4,697 Credit loss (recoveries) expense (1,252) (146) 270 — (1,128) December 31, 2021 1,599 1,057 913 — 3,569 Credit loss expense (recoveries) 1,195 (279) (645) — 271 December 31, 2022 $ 2,794 $ 778 $ 268 $ — $ 3,840 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of December 31, 2022 and December 31, 2021 included $52,000 and $218,000, respectively, in the line entitled “accounts receivable, net” and $216,000 and $695,000, respectively, in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets.
Financing Receivable Credit Quality Indicators	The following table presents the amortized cost basis of our investing receivables, tenant notes receivable and sales-type lease receivables by credit risk classification, by origination year as of December 31, 2022 (in thousands): Origination Year 2017 and Earlier 2018 2019 2020 2021 2022 Total Investing receivables: Credit risk classification: Investment grade $ 60,437 $ — $ — $ 1,887 $ 7,379 $ — $ 69,703 Non-investment grade — — 15 — — 17,697 17,712 Total $ 60,437 $ — $ 15 $ 1,887 $ 7,379 $ 17,697 $ 87,415 Tenant notes receivable: Credit risk classification: Investment grade $ — $ 807 $ 40 $ 195 $ — $ — $ 1,042 Non-investment grade 151 98 89 1,565 — — 1,903 Total $ 151 $ 905 $ 129 $ 1,760 $ — $ — $ 2,945 Sales-type lease receivable: Credit risk classification: Investment grade $ — $ — $ — $ 5,666 $ — $ — $ 5,666

Earnings Per Share ("EPS") (Tab

Earnings Per Share ("EPS") (Tables)	12 Months Ended
	Dec. 31, 2022
Earnings Per Share [Abstract]
Summary of calculation of numerator and denominator in basic and diluted earnings per share	Summaries of the numerator and denominator for purposes of basic and diluted EPS calculations are set forth below (in thousands, except per share data): For the Years Ended December 31, 2022 2021 2020 Numerator: Income from continuing operations $ 149,249 $ 78,220 $ 100,601 Income from continuing operations attributable to noncontrolling interests (5,372) (4,994) (5,477) Income from continuing operations attributable to share-based compensation awards for basic EPS (451) (467) (433) Numerator for basic EPS from continuing operations attributable to COPT common shareholders $ 143,426 $ 72,759 $ 94,691 Redeemable noncontrolling interests (169) (128) — Adjustment to income from continuing operations attributable to share-based compensation awards for diluted EPS 78 44 27 Numerator for diluted EPS from continuing operations attributable to COPT common shareholders $ 143,335 $ 72,675 $ 94,718 Discontinued operations 29,573 3,358 2,277 Discontinued operations attributable to noncontrolling interests (421) (43) (27) Income from discontinued operations attributable to share-based compensation awards for diluted EPS (90) 6 2 Numerator for diluted EPS on net income attributable to COPT common shareholders $ 172,397 $ 75,996 $ 96,970 Denominator (all weighted averages): Denominator for basic EPS (common shares) 112,073 111,960 111,788 Dilutive effect of redeemable noncontrolling interests 116 128 — Dilutive effect of share-based compensation awards 431 330 288 Denominator for diluted EPS (common shares) 112,620 112,418 112,076 Basic EPS: Income from continuing operations attributable to COPT common shareholders $ 1.28 $ 0.65 $ 0.85 Discontinued operations attributable to COPT common shareholders 0.26 0.03 0.02 Net income attributable to COPT common shareholders $ 1.54 $ 0.68 $ 0.87 Diluted EPS: Income from continuing operations attributable to COPT common shareholders $ 1.27 $ 0.65 $ 0.85 Discontinued operations attributable to COPT common shareholders 0.26 0.03 0.02 Net income attributable to COPT common shareholders $ 1.53 $ 0.68 $ 0.87
Schedule of securities excluded from computation of diluted earnings per share	Our diluted EPS computations do not include the effects of the following securities since the conversions of such securities would increase diluted EPS for the respective periods (in thousands): Weighted Average Shares Excluded from Denominator for the Years Ended December 31, 2022 2021 2020 Conversion of common units 1,454 1,257 1,236 Conversion of redeemable noncontrolling interests 866 804 957 Conversion of Series I Preferred Units — — 171

Organization (Narrative) (Detai

Organization (Narrative) (Details) - 12 months ended Dec. 31, 2022 ft² in Millions	property	ft²	a	shares
Corporate Office Properties, L.P | Preferred units
Investments in real estate
Limited partners' capital account, units outstanding (in shares) | shares				0
Corporate Office Properties, L.P | COPT | Common Units
Investments in real estate
Percentage ownership in operating partnership	98%
Operating properties
Investments in real estate
Number of real estate properties	194
Area of real estate property (in sqft or acres) | ft²		23
Operating properties | Office Properties
Investments in real estate
Number of real estate properties	166
Area of real estate property (in sqft or acres) | ft²		17.7
Operating properties | Single-tenant data centers
Investments in real estate
Number of real estate properties	28
Area of real estate property (in sqft or acres) | ft²		5.3
Properties under development
Investments in real estate
Number of real estate properties	7
Area of real estate property (in sqft or acres) | ft²		1
Properties under development | Office Properties
Investments in real estate
Number of real estate properties	5
Properties under development | Single-tenant data centers
Investments in real estate
Number of real estate properties	2
Properties Under Development, Partially-Operational
Investments in real estate
Number of real estate properties	2
Land controlled for future development
Investments in real estate
Area of real estate property (in sqft or acres)		9.5	710
Other land
Investments in real estate
Area of real estate property (in sqft or acres) | a			43
Unconsolidated Real Estate Joint Ventures
Investments in real estate
Number of real estate properties	21
Unconsolidated Real Estate Joint Ventures | Operating properties | Single-tenant data centers
Investments in real estate
Number of real estate properties	21

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Properties and Impairment) (Details)	12 Months Ended
	Dec. 31, 2022
Properties
Period after the cessation of major construction activities for considering property as operational if leases have not commenced earlier (in years)	1 year
Period after the cessation of major construction activities for considering property as partially operational if leases have commenced earlier (in years)	1 year
Property, Plant and Equipment [Line Items]
Period used recovery analysis for long-lived assets to be held and used that may be impaired (in years)	10 years
Minimum | Buildings and building improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Minimum | Land improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Minimum | Equipment and personal property
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Maximum | Buildings and building improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Maximum | Land improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Maximum | Equipment and personal property
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Receivables and Credit Losses) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2020	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss impact		$ 5,541
Accounting Standards Update 2016-13 | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Allowance for credit loss impact	$ 5,500

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Lease and Other Property Revenue) (Details)	Dec. 31, 2022
United States Government
Lessor, Lease, Description [Line Items]
Renewal term	1 year

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Construction Contract and Other Service Revenues) (Details)	Dec. 31, 2022 compensation_arrangement
Accounting Policies [Abstract]
Number of compensation arrangements	3

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Share-Based Compensation) (Details)	12 Months Ended
	Dec. 31, 2022 form
Accounting Policies [Abstract]
Number of forms of share based compensation plans	4

Summary of Significant Accoun_9

Summary of Significant Accounting Policies (Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Approximate amount by which basis of assets and liabilities for tax reporting purposes is higher (lower) than amount reported on consolidated balance sheet	$ (7)
Common Shares
Income Tax Disclosure [Line Items]
Ordinary income	68.20%	33.30%	45.10%
Long-term capital gain	31.80%	57.30%	54.90%
Return of capital	0%	9.40%	0%

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2022	Dec. 31, 2021
Assets and liabilities measured at fair value on a recurring basis
Marketable securities in deferred compensation plan		$ 1,831	$ 2,556
Fair Value, Recurring | Deferred compensation plan | Trustees and Management
Assets and liabilities measured at fair value on a recurring basis
Maximum percentage of participants' compensation which is deferrable (as a percent)	100%
Marketable securities in deferred compensation plan		$ 1,800	$ 2,600

Fair Value Measurements (Recurr

Fair Value Measurements (Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Assets:
Marketable securities in deferred compensation plan	$ 1,831	$ 2,556
Fair value measurement on a recurring basis
Assets:
Other marketable securities		33
Interest rate derivatives	2,631	355
Total assets	4,462	2,944
Liabilities:
Deferred compensation plan liability	1,831	2,556
Interest rate derivatives		3,644
Total liabilities		6,200
Fair value measurement on a recurring basis | Mutual funds
Assets:
Marketable securities in deferred compensation plan	1,762	2,485
Fair value measurement on a recurring basis | Other
Assets:
Marketable securities in deferred compensation plan	69	71
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Other marketable securities		33
Interest rate derivatives	0	0
Total assets	1,831	2,589
Liabilities:
Deferred compensation plan liability	0	0
Interest rate derivatives		0
Total liabilities		0
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds
Assets:
Marketable securities in deferred compensation plan	1,762	2,485
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Assets:
Marketable securities in deferred compensation plan	69	71
Fair value measurement on a recurring basis | Significant Other Observable Inputs(Level 2)
Assets:
Other marketable securities		0
Interest rate derivatives	2,631	355
Total assets	2,631	355
Liabilities:
Deferred compensation plan liability	1,831	2,556
Interest rate derivatives		3,644
Total liabilities		6,200
Fair value measurement on a recurring basis | Significant Other Observable Inputs(Level 2) | Mutual funds
Assets:
Marketable securities in deferred compensation plan	0	0
Fair value measurement on a recurring basis | Significant Other Observable Inputs(Level 2) | Other
Assets:
Marketable securities in deferred compensation plan	0	0
Fair value measurement on a recurring basis | Significant Unobservable  Inputs (Level 3)
Assets:
Other marketable securities		0
Interest rate derivatives	0	0
Total assets	0	0
Liabilities:
Deferred compensation plan liability	0	0
Interest rate derivatives		0
Total liabilities		0
Fair value measurement on a recurring basis | Significant Unobservable  Inputs (Level 3) | Mutual funds
Assets:
Marketable securities in deferred compensation plan	0	0
Fair value measurement on a recurring basis | Significant Unobservable  Inputs (Level 3) | Other
Assets:
Marketable securities in deferred compensation plan	$ 0	$ 0

Properties, Net (Operating prop

Properties, Net (Operating properties, net) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating properties, net
Gross	$ 4,986,537	$ 4,959,709	$ 4,686,802	$ 4,348,006
Operating properties, net	3,258,899	3,090,510
Operating properties, net
Operating properties, net
Less: Accumulated depreciation	(1,267,434)	(1,152,523)
Operating properties, net	3,258,899	3,090,510
Operating properties, net | Land
Operating properties, net
Gross	539,809	572,900
Operating properties, net | Buildings and improvements
Operating properties, net
Gross	$ 3,986,524	$ 3,670,133

Properties, Net (Narrative) (De

Properties, Net (Narrative) (Details) ft² in Thousands, $ in Thousands							3 Months Ended	12 Months Ended
	Jan. 10, 2023 USD ($) property	Dec. 14, 2022 USD ($) property	Jan. 25, 2022 USD ($)	Dec. 30, 2021 USD ($)	Jun. 02, 2021 USD ($) property	Oct. 30, 2020 USD ($) property	Sep. 30, 2020 USD ($)	Dec. 31, 2022 USD ($) ft² property	Dec. 31, 2021 USD ($) ft² property	Dec. 31, 2020 USD ($) ft² property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage sold								90%	90%	90%
Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]								Discontinued operations
Number of properties sold | property								2	2	2
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]				Gain on sales of real estate				Gain on sales of real estate	Gain on sales of real estate	Gain on sales of real estate
Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain on sales of real estate
Quark JV LLC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %		10%
BRE- COPT 3
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %					10%
BRE- COPT 2
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %						10%
Newly-Formed Joint Venture | Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %	10%
Baltimore, Maryland
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges							$ 1,500
Newly-developed properties placed in service
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²								1,300	766	1,800
Number of real estate properties | property								9	8	11
Expansion of Fully-Operational Properties Placed in Service
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²								14		42
Number of real estate properties | property								1		3
Properties under development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²								1,000
Number of real estate properties | property								7
Properties Under Development, Partially-Operational
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties | property								2
Redeveloped Property Placed in Service
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²										21
Data Center Shells in Northern Virginia | Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties held for sale | property								3
Ownership percentage sold		90%			90%	90%
Transaction value		$ 67,000			$ 118,800	$ 89,700
Number of properties sold | property		2			2	2
Proceeds from sale		$ 60,300			$ 106,900	$ 80,700
Gain on disposal								$ 19,200	$ 40,200	$ 30,000
Data Center Shells in Northern Virginia | Disposed of by sale | Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage sold	90%
Transaction value	$ 211,300
Number of properties sold | property	3
Proceeds from sale	$ 190,200
Gain on disposal	$ 49,000
Wholesale Data Center | Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Transaction value			$ 222,500
Gain on disposal			$ 28,600					$ 28,564	$ 0	$ 0
Other Data Center Shells | Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale				$ 30,000
Gain on disposal				$ 25,900

Properties, Net (Schedule of As

Properties, Net (Schedule of Assets Held for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Real Estate [Abstract]
Properties, net	$ 156,691	$ 191,857
Deferred rent receivable	4,595	462
Deferred leasing costs, net	0	307
Intangible assets on property acquisitions, net	0	73
Assets held for sale, net	$ 161,286	$ 192,699

Properties, Net (Components of

Properties, Net (Components of Discontinued Operations) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 25, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from real estate operations		$ 1,980	$ 30,490	$ 27,011
Property operating expenses		(971)	(16,842)	(13,044)
Discontinued operations		29,573	3,358	2,277
Discontinued Operations, Disposed of by Sale | Wholesale Data Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from real estate operations		1,980	30,490	27,011
Property operating expenses		(971)	(16,842)	(13,044)
Depreciation and amortization associated with real estate operations		0	(10,290)	(11,690)
Gain on sale of real estate	$ 28,600	28,564	0	0
Discontinued operations		29,573	3,358	2,277
Cash flows from operating activities		5,757	10,930	16,051
Cash flows from investing activities		$ 220,565	$ (1,912)	$ (11,485)

Leases (Lease Revenue) (Details

Leases (Lease Revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessor, Lease, Description [Line Items]
Lease revenue	$ 580,169	$ 553,668	$ 509,114
Continuing Operations
Lessor, Lease, Description [Line Items]
Fixed	453,907	436,768	404,244
Variable	126,262	116,900	104,870
Lease revenue	580,169	553,668	509,114
Discontinued Operations
Lessor, Lease, Description [Line Items]
Fixed	1,500	22,300	21,300
Variable	$ 527	$ 8,200	$ 5,700

Leases (Percentage of Revenue)

Leases (Percentage of Revenue) (Details) - United States Government - Concentration risk	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lease Revenue From Continuing Operations, Risk Benchmark
Concentration Risk [Line Items]
Percentage of revenue	37%	36%	37%
Fixed Lease Revenue From Continuing Operations Benchmark
Concentration Risk [Line Items]
Percentage of revenue	27%	26%	27%

Leases (Payments to be Received

Leases (Payments to be Received) (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Operating leases
2023	$ 443,092
2024	415,914
2025	336,522
2026	269,778
2027	236,079
Thereafter	1,114,240
Total contractual payments	2,815,625
Sales-type leases
2023	960
2024	960
2025	960
2026	960
2027	960
Thereafter	2,596
Total contractual payments	7,396
Less: Amount representing interest	(1,730)
Net investment in sales-type leases	$ 5,666

Leases (Lessee Arrangements) (D

Leases (Lessee Arrangements) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) Lease
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 39.2
Minimum | Land Leases
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	26 years
Maximum | Land Leases
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	78 years
Washington DC
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 9.7
Lessee, Remaining term of contract	77 years
Lessee, Number of lease contracts | Lease	2
Baltimore, Maryland
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 6.4
Lessee, Remaining term of contract	26 years
Optional renewal term	49 years
Phoenix, Arizona
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 3.6
Lessee, Remaining term of contract	2 years
Optional renewal term	5 years
LW Redstone Company, LLC | Huntsville, Alabama
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 11.4
Lessee, Number of lease contracts | Lease	17
Optional renewal term	25 years
LW Redstone Company, LLC | Huntsville, Alabama | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	40 years
LW Redstone Company, LLC | Huntsville, Alabama | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	49 years
M Square Associates, LLC | College Park, Maryland
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 6
Lessee, Number of lease contracts | Lease	4
M Square Associates, LLC | College Park, Maryland | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	60 years
M Square Associates, LLC | College Park, Maryland | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	71 years
Fort Meade/BW Corridor
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 2.1
Lessee, Remaining term of contract	45 years
Lessee, Number of lease contracts | Lease	2

Leases (Property right-of-use A

Leases (Property right-of-use Assets ) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Leases [Abstract]
Operating leases - Property	$ 37,020	$ 38,361
Finance leases - Property	2,207	2,238
Total right-of-use assets	39,227	40,599
Property - operating lease liabilities	$ 28,759	$ 29,342
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Prepaid expenses and other assets, net	Prepaid expenses and other assets, net

Leases (Weighted Average Terms

Leases (Weighted Average Terms and Discount Rates) (Details)	Dec. 31, 2022
Leases [Abstract]
Operating leases, Weighted average remaining lease term	53 years
Operating lease, Weighted average discount rate	7.19%

Leases (Property Lease Cost) (D

Leases (Property Lease Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Lease costs	$ 4,210	$ 4,087	$ 2,574
Property operating expenses
Lessee, Lease, Description [Line Items]
Property leases - fixed	4,114	4,011	2,413
Property leases - variable	65	45	127
Finance lease cost - amortization of property right-of-use assets	$ 31	$ 31	$ 34

Leases (Supplemental Cash Flow

Leases (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating cash flows for operating leases	$ 3,355	$ 3,206	$ 1,694
Financing cash flows for financing leases	$ 0	$ 14	$ 674

Leases (Lease Liabilities) (Det

Leases (Lease Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
December 31, 2022
2023	$ 3,399
2024	3,451
2025	1,797
2026	1,578
2027	1,593
Thereafter	124,341
Total lease payments	136,159
Less: Amount representing interest	(107,400)
Lease liability	$ 28,759	$ 29,342

Real Estate Joint Ventures (Con

Real Estate Joint Ventures (Consolidated Real Estate Joint Ventures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Investments in consolidated real estate joint ventures
Total Assets	$ 4,257,275	$ 4,262,452
Total Liabilities	2,509,527	$ 2,578,479
LW Redstone Company, LLC
Investments in consolidated real estate joint ventures
Preferred distributions of annual operating cash flows to partner	1,200
Variable Interest Entity, Primary Beneficiary
Investments in consolidated real estate joint ventures
Total Assets	864,801
Total Liabilities	170,271
Variable Interest Entity, Primary Beneficiary | Asset Pledged as Collateral
Investments in consolidated real estate joint ventures
Total Assets	148,047
Variable Interest Entity, Primary Beneficiary | Mortgage and other secured debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 101,813
Variable Interest Entity, Primary Beneficiary | LW Redstone Company, LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	85%
Total Assets	$ 595,565
Total Liabilities	118,375
Variable Interest Entity, Primary Beneficiary | LW Redstone Company, LLC | Asset Pledged as Collateral
Investments in consolidated real estate joint ventures
Total Assets	88,646
Variable Interest Entity, Primary Beneficiary | LW Redstone Company, LLC | Mortgage and other secured debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 52,014
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	95%
Total Assets	$ 168,819
Total Liabilities	854
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC | Asset Pledged as Collateral
Investments in consolidated real estate joint ventures
Total Assets	0
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC | Mortgage and other secured debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 0
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	50%
Total Assets	$ 100,417
Total Liabilities	51,042
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC | Asset Pledged as Collateral
Investments in consolidated real estate joint ventures
Total Assets	59,401
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC | Mortgage and other secured debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 49,799

Real Estate Joint Ventures (Nar

Real Estate Joint Ventures (Narrative) (Details) $ in Thousands, ft² in Millions		12 Months Ended
	Dec. 22, 2020 USD ($) property	Dec. 31, 2022 USD ($) ft² property	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) property	Dec. 21, 2020
Investments in real estate joint ventures
Ownership percentage sold		90%	90%	90%
Number of properties sold | property		2	2	2
Gain on sale of investment in unconsolidated real estate joint venture		$ 0	$ 0	$ 29,416
BRE-COPT 2
Investments in real estate joint ventures
Nominal Ownership %	10%	10%		10%
BRE-COPT 3
Investments in real estate joint ventures
Nominal Ownership %		10%	10%
Quark
Investments in real estate joint ventures
Nominal Ownership %		10%
GI-COPT DC Partnership LLC
Investments in real estate joint ventures
Nominal Ownership %					50%
Ownership interest sold of the original 50% owned	80%
Proceeds from sale of investment in unconsolidated real estate joint venture	$ 60,000
Gain on sale of investment in unconsolidated real estate joint venture	$ 29,400
LW Redstone Company, LLC
Investments in real estate joint ventures
Partner's capital account upon formation		$ 9,000
Percentage of cumulative preferred returns of cash flows on partners' invested capital		13.50%
Percentage of cumulative preferred returns of cash flows on our invested capital		13.50%
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company		85%
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the entity's partners		15%
Number of years following construction commencement threshold achievement before partner's interest can be purchased at fair value		5 years
Construction commencement threshold (in square feet) | ft²		4.4
Construction commencement completed (in sqft) | ft²		2.5
LW Redstone Company, LLC | Maximum
Investments in real estate joint ventures
Infrastructure costs anticipated to be funded by entity for reimbursement by the City of Huntsville (in dollars)		$ 76,000
LW Redstone Company, LLC | Notes receivable from the City of Huntsville
Investments in real estate joint ventures
Infrastructure costs funded to date for reimbursement by the City of Huntsville		$ 70,400
Stevens Investors, LLC | Maximum
Investments in real estate joint ventures
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company		85%
Stevens Investors, LLC | Minimum
Investments in real estate joint ventures
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company		60%
M Square Associates, LLC
Investments in real estate joint ventures
Percentage of residual amounts distributed to each member		50%
GI-COPT DC Partnership LLC | BRE-COPT 2
Investments in real estate joint ventures
Number of properties sold | property	6

Real Estate Joint Ventures (Unc

Real Estate Joint Ventures (Unconsolidated Real Estate Joint Ventures) (Details) $ in Thousands	Dec. 31, 2022 USD ($) property	Dec. 31, 2021 USD ($)	Dec. 31, 2020	Dec. 22, 2020
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated real estate joint ventures	$ 21,460	$ 39,889
Other liabilities	$ 18,556	17,729
Unconsolidated Real Estate Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property	21
Real estate equity method investments	$ 20,001	39,889
Investment in unconsolidated real estate joint ventures	21,500
Other liabilities	$ 1,500
BREIT COPT DC JV LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of real estate properties | property	9
Real estate equity method investments	$ 11,568	12,460
Quark
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of real estate properties | property	2
Real estate equity method investments	$ 6,758	$ 0
BRE-COPT 3
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%	10%
Number of real estate properties | property	2
Real estate equity method investments	$ 3,134	$ 11,850
BRE-COPT 2
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%		10%	10%
Number of real estate properties | property	8
Real estate equity method investments	$ (1,459)	15,579
Difference between the joint venture's cost basis and the entity's share of underlying equity in the net assets	$ 7,000	$ 7,200

Intangible Assets on Property_3

Intangible Assets on Property Acquisitions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 197,468	$ 198,724
Accumulated Amortization	187,509	184,157
Net Carrying Amount	9,959	14,567
Amortization of the intangible assets	$ 4,600	4,700	$ 8,000
Weighted average amortization period of intangible assets	6 years
Estimated future amortization expense associated with the intangible asset categories for the next five years
2023	$ 2,900
2024	1,900
2025	1,600
2026	1,000
2027	717
In-place lease value
Intangible assets on real estate acquisitions
Gross Carrying Amount	125,207	125,591
Accumulated Amortization	120,178	118,983
Net Carrying Amount	$ 5,029	6,608
Weighted average amortization period of intangible assets	4 years
Tenant relationship value
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 57,210	58,082
Accumulated Amortization	52,803	50,701
Net Carrying Amount	$ 4,407	7,381
Weighted average amortization period of intangible assets	8 years
Above-market leases
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 13,718	13,718
Accumulated Amortization	13,476	13,435
Net Carrying Amount	$ 242	283
Weighted average amortization period of intangible assets	5 years
Other
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 1,333	1,333
Accumulated Amortization	1,052	1,038
Net Carrying Amount	$ 281	$ 295
Weighted average amortization period of intangible assets	20 years

Investing Receivables (Details)

Investing Receivables (Details) - Investing Receivables - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 87,415	$ 83,825
Allowance for credit losses	(2,794)	(1,599)	$ (2,851)	$ 0
Investing receivables, net	84,621	82,226
Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	69,703	77,784
Other investing loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 17,712	$ 6,041

Investing Receivables (Narrativ

Investing Receivables (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing Receivable, Accrued Interest, after Allowance for Credit Loss, Statement of Financial Position [Extensible Enumeration]	Investing receivables (net of allowance for credit losses of $2,794 and $1,599, respectively)
Investing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable, fair value disclosure	$ 87	$ 84
Notes receivable from the City of Huntsville | LW Redstone Company, LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	9.95%
Notes receivable, maximum initial maturity term	30 years
Other investing loans receivable | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	8%
Other investing loans receivable | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	14%
Investing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable, net of allowance for credit losses	$ 2.9	$ 5.3
Investing Receivables | Other investing loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other investing loans receivable, remaining term	1 year

Prepaid Expenses and Other As_3

Prepaid Expenses and Other Assets, Net (Prepaid Expenses and Other Assets, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Prepaid Expense and Other Assets [Abstract]
Construction contract costs in excess of billings, net	$ 22,331	$ 22,384
Prepaid expenses	21,058	20,058
Furniture, fixtures and equipment, net	8,286	9,599
Non-real estate equity investments	5,974	5,544
Net investment in sales-type leases	5,666	6,194
Deferred financing costs, net	5,210	1,314
Deposits	4,616	3,910
Restricted cash	4,172	4,054	$ 3,664	$ 3,397
Interest rate derivatives	2,631	355
Property - finance right-of-use assets	2,207	2,238
Marketable securities in deferred compensation plan	1,831	2,556
Deferred tax asset, net	1,405	1,841
Other assets	1,230	1,443
Prepaid expenses and other assets, net	$ 86,617	$ 81,490

Prepaid Expenses and Other As_4

Prepaid Expenses and Other Assets, Net (Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Tax Credit Carryforward [Line Items]
Deferred tax asset, net	$ 1,405	$ 1,841
TRS
Tax Credit Carryforward [Line Items]
Operating loss carry forward	1,533	1,835
-128000	(128)
Property		30
Valuation allowance	0	(24)
Deferred tax asset, net	$ 1,405	$ 1,841

Debt, Net (Debt Schedule) (Deta

Debt, Net (Debt Schedule) (Details)	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Nov. 17, 2021 USD ($)	Aug. 11, 2021 USD ($)	Mar. 11, 2021 USD ($)	Dec. 31, 2020 USD ($)	Sep. 17, 2020 USD ($)
Debt
Carrying Value	$ 2,231,794,000	$ 2,272,304,000
Revolving Credit Facility
Debt
Carrying Value	$ 211,000,000	76,000,000
Weighted average interest rate	5.47%
Term Loan Facility
Debt
Interest rate	5.72%
Debt instrument, face amount						$ 400,000,000
Carrying Value	$ 123,948,000	299,420,000
Unsecured note payable
Debt
Interest rate	0%
Carrying Value	$ 597,000	753,000
Unamortized discount included in carrying value	$ 65,000	108,000
Secured Overnight Financing Rate | Revolving Credit Facility
Debt
Variable rate, additional spread	0.0010
Secured Overnight Financing Rate | Revolving Credit Facility | Minimum
Debt
Variable rate, spread	0.725%
Secured Overnight Financing Rate | Revolving Credit Facility | Maximum
Debt
Variable rate, spread	1.40%
Secured Overnight Financing Rate | Term Loan Facility
Debt
Variable rate, additional spread	0.0010
Secured Overnight Financing Rate | Term Loan Facility | Minimum
Debt
Variable rate, spread	0.85%
Secured Overnight Financing Rate | Term Loan Facility | Maximum
Debt
Variable rate, spread	1.70%
Mortgage and other secured debt
Debt
Carrying Value	$ 117,751,000	120,627,000
Mortgage and other secured debt | Fixed rate mortgage debt
Debt
Carrying Value	$ 84,433,000	86,960,000
Weighted average interest rate	4.07%
Mortgage and other secured debt | Fixed rate mortgage debt | Minimum
Debt
Interest rate	3.82%
Mortgage and other secured debt | Fixed rate mortgage debt | Maximum
Debt
Interest rate	4.62%
Mortgage and other secured debt | Variable rate secured loans
Debt
Carrying Value	$ 33,318,000	33,667,000
Mortgage and other secured debt | Secured Overnight Financing Rate | Variable rate secured loans
Debt
Variable rate, additional spread	0.0010
Weighted average interest rate	5.58%
Mortgage and other secured debt | Secured Overnight Financing Rate | Variable rate secured loans | Interest rate swaps
Debt
Weighted average interest rate	2.45%
Mortgage and other secured debt | Secured Overnight Financing Rate | Variable rate secured loans | Minimum
Debt
Variable rate, spread	1.45%
Mortgage and other secured debt | Secured Overnight Financing Rate | Variable rate secured loans | Maximum
Debt
Variable rate, spread	1.55%
Senior Notes | 2.25%, $400,000 aggregate principal
Debt
Interest rate	2.25%
Debt instrument, face amount	$ 400,000,000						$ 400,000,000
Carrying Value	396,539,000	395,491,000
Unamortized discount included in carrying value	$ 2,800,000	3,600,000
Effective interest rate on debt	2.48%
Senior Notes | 2.00%, $400,000 aggregate principal
Debt
Interest rate	2%
Debt instrument, face amount	$ 400,000,000			$ 400,000,000
Carrying Value	396,988,000	396,512,000
Unamortized discount included in carrying value	$ 2,100,000	2,500,000
Effective interest rate on debt	2.09%
Senior Notes | 2.75%, $600,000 aggregate principal
Debt
Interest rate	2.75%
Debt instrument, face amount	$ 600,000,000				$ 600,000,000
Carrying Value	590,123,000	589,060,000
Unamortized discount included in carrying value	$ 8,500,000	9,500,000
Effective interest rate on debt	2.94%
Senior Notes | 2.90%, $400,000 aggregate principal
Debt
Interest rate	2.90%
Debt instrument, face amount	$ 400,000,000		$ 400,000,000
Carrying Value	394,848,000	394,441,000
Unamortized discount included in carrying value	$ 4,200,000	4,500,000
Effective interest rate on debt	3.01%
Loans Payable
Debt
Net deferred financing costs	$ 5,400,000	$ 5,800,000

Debt, Net (Debt Maturities) (De

Debt, Net (Debt Maturities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule on basis of which debt matures
2023	$ 18,954
2024	29,983
2025	23,717
2026	782,300
2027	0
Thereafter	1,400,000
Total	2,254,954
Net discounts and deferred financing costs	23,200
Capitalized interest costs	$ 6,700	$ 6,500	$ 12,100

Debt, Net (Fair Value of Debt)

Debt, Net (Fair Value of Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Carrying Amount
Debt Instrument [Line Items]
Long-term debt	$ 2,231,794	$ 2,272,304
Carrying Amount | Unsecured Senior Notes
Debt Instrument [Line Items]
Long-term debt	1,778,498	1,775,504
Carrying Amount | Other fixed-rate debt
Debt Instrument [Line Items]
Long-term debt	85,030	87,713
Carrying Amount | Variable-rate debt
Debt Instrument [Line Items]
Long-term debt	368,266	409,087
Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	1,881,787	2,306,928
Estimated Fair Value | Unsecured Senior Notes
Debt Instrument [Line Items]
Long-term debt	1,433,561	1,809,950
Estimated Fair Value | Other fixed-rate debt
Debt Instrument [Line Items]
Long-term debt	80,330	87,339
Estimated Fair Value | Variable-rate debt
Debt Instrument [Line Items]
Long-term debt	$ 367,896	$ 409,639

Debt, Net (Narrative) (Details)

Debt, Net (Narrative) (Details)					12 Months Ended
	Nov. 17, 2021 USD ($)	Aug. 11, 2021 USD ($)	Mar. 11, 2021 USD ($)	Sep. 17, 2020 USD ($)	Dec. 31, 2022 USD ($) extension	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Oct. 26, 2022 USD ($)	Nov. 18, 2021 USD ($)	Apr. 12, 2021 USD ($)	Oct. 19, 2020 USD ($)
Debt Instrument [Line Items]
Loss on early extinguishment of debt					$ (609,000)	$ (100,626,000)	$ (7,306,000)
Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average interest rate					5.47%
Revolving Credit Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, additional spread					0.0010
Term Loan Facility
Debt Instrument [Line Items]
Number of extensions | extension					2
Extension option period					12 months
Line of credit facility, extension fee					0.125%
Loan increase							150,000,000
Repayments of term loan					$ 300,000,000	100,000,000
Loan amount							400,000,000
Interest rate					5.72%
Term Loan Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, additional spread					0.0010
Minimum | Revolving Credit Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, spread					0.725%
Minimum | Term Loan Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, spread					0.85%
Maximum | Revolving Credit Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, spread					1.40%
Maximum | Term Loan Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, spread					1.70%
Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average borrowings					$ 202,800,000	$ 135,800,000
Weighted average interest rate					3.31%	1.18%
Revolving Credit Facility | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, additional spread					0.0010
Revolving Credit Facility | Minimum | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, spread					0.725%
Revolving Credit Facility | Maximum | Secured Overnight Financing Rate
Debt Instrument [Line Items]
Variable rate, spread					1.40%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity					$ 600,000,000			$ 600,000,000
Number of extensions | extension					2
Extension option period					6 months
Line of credit facility, extension fee					0.0625%
Remaining borrowing capacity					$ 389,000,000
Line of Credit | Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee percentage					0.125%
Line of Credit | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee percentage					0.30%
Unsecured Debt | Term Loan Facility
Debt Instrument [Line Items]
Loan amount								$ 125,000,000
Senior Notes
Debt Instrument [Line Items]
Redemption price					100%
Senior Notes | 2.25% Senior Notes
Debt Instrument [Line Items]
Loan amount				$ 400,000,000	$ 400,000,000
Interest rate					2.25%
Initial offering price				99.42%
Proceeds from issuance of debt				$ 395,300,000
Basis point used in determining redemption price prior to maturity					0.35%
Senior Notes | 2.75%, $600,000 aggregate principal
Debt Instrument [Line Items]
Loan amount			$ 600,000,000		$ 600,000,000
Interest rate					2.75%
Initial offering price			98.95%
Proceeds from issuance of debt			$ 589,800,000
Senior Notes | 2.75%, $600,000 aggregate principal | Adjusted Treasury
Debt Instrument [Line Items]
Basis point used in determining redemption price prior to maturity					0.25%
Senior Notes | 2.00%, $400,000 aggregate principal
Debt Instrument [Line Items]
Loan amount		$ 400,000,000			$ 400,000,000
Interest rate					2%
Initial offering price		99.97%
Proceeds from issuance of debt		$ 397,400,000
Senior Notes | 2.00%, $400,000 aggregate principal | Adjusted Treasury
Debt Instrument [Line Items]
Basis point used in determining redemption price prior to maturity					0.20%
Senior Notes | 2.90%, $400,000 aggregate principal
Debt Instrument [Line Items]
Loan amount	$ 400,000,000				$ 400,000,000
Interest rate					2.90%
Initial offering price	99.53%
Proceeds from issuance of debt	$ 395,400,000
Senior Notes | 2.90%, $400,000 aggregate principal | Adjusted Treasury
Debt Instrument [Line Items]
Basis point used in determining redemption price prior to maturity					0.25%
Senior Notes | 3.70% Senior Notes
Debt Instrument [Line Items]
Repurchased face amount				122,900,000							$ 177,100,000
Repurchase face amount plus prepayment premium				$ 126,000,000							$ 180,900,000
Loss on early extinguishment of debt							$ (7,300,000)
Senior Notes | 3.60% Senior Notes and 5.25% Senior Notes
Debt Instrument [Line Items]
Loss on early extinguishment of debt						$ (58,400,000)
Senior Notes | 3.60% Senior Notes
Debt Instrument [Line Items]
Repurchased face amount			184,400,000							$ 165,600,000
Repurchase face amount plus prepayment premium			196,700,000							176,300,000
Senior Notes | 5.250% Senior Notes
Debt Instrument [Line Items]
Repurchased face amount			145,600,000							104,400,000
Repurchase face amount plus prepayment premium			$ 164,700,000							$ 117,700,000
Senior Notes | 5.0% Senior Notes
Debt Instrument [Line Items]
Repurchased face amount									$ 300,000,000
Repurchase face amount plus prepayment premium									$ 336,400,000
Loss on early extinguishment of debt						$ (38,200,000)

Interest Rate Derivatives - Sch

Interest Rate Derivatives - Schedule of key terms and fair values of interest rate swap derivatives (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 28, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair values of interest rate swap derivatives
Fair value of interest rate swaps		$ 2,631
Payments for hedge, investing activities		625	$ 0	$ 53,130
Designated
Fair values of interest rate swap derivatives
Fair value of interest rate swaps			(3,289)
Interest rate swap, effective August 1, 2019 | Designated
Fair values of interest rate swap derivatives
Notional Amount		$ 10,880
Fixed Rate		1.678%
Fair value of interest rate swaps		$ 806	(234)
Notional amount of interest rate derivatives after scheduled amortization		$ 10,000
Interest rate swap, effective August 1, 2019 | Designated | Secured Overnight Financing Rate
Fair values of interest rate swap derivatives
Floating Rate Index		0.10%
Interest rate swap, effective April 2020, swap two | Designated
Fair values of interest rate swap derivatives
Notional Amount		$ 22,775
Fixed Rate		0.573%
Fair value of interest rate swaps		$ 1,825	355
Notional amount of interest rate derivatives after scheduled amortization		$ 22,100
Interest rate swap, effective April 2020, swap two | Designated | Secured Overnight Financing Rate
Fair values of interest rate swap derivatives
Floating Rate Index		0.10%
Interest rate swap, effective September 1, 2016, swap one | Designated
Fair values of interest rate swap derivatives
Notional Amount		$ 100,000
Fixed Rate		1.901%
Fair value of interest rate swaps		$ 0	(1,361)
Interest rate swap, effective September 1, 2016, swap two | Designated
Fair values of interest rate swap derivatives
Notional Amount		$ 100,000
Fixed Rate		1.905%
Fair value of interest rate swaps		$ 0	(1,365)
Interest rate swap, effective September 1, 2016, swap three | Not Designated as Hedging Instrument
Fair values of interest rate swap derivatives
Notional Amount		$ 50,000
Fixed Rate		1.908%
Fair value of interest rate swaps		$ 0	$ (684)
Payments for hedge, investing activities	$ 625

Interest Rate Derivatives - S_2

Interest Rate Derivatives - Schedule of fair value and balance sheet classification of interest rate derivatives (Details) - Interest rate swaps - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Prepaid expenses and other assets, net
Fair values of interest rate swap derivatives
Interest rate swaps designated as cash flow hedges	$ 2,631	$ 355
Other liabilities
Fair values of interest rate swap derivatives
Interest rate swaps designated as cash flow hedges	0	(2,960)
Interest rate swap not designated	$ 0	$ (684)

Interest Rate Derivatives - S_3

Interest Rate Derivatives - Schedule of effect of interest rate derivatives on consolidated statements of operations and comprehensive income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair values of interest rate swap derivatives
Amount of Income (Loss) Recognized in AOCI/AOCL on Derivatives	$ 4,730	$ 1,379	$ (39,454)
Amount of Loss Reclassified from AOCI/AOCL into Interest Expense on Statement of Operations	(996)	(5,048)	(3,725)
Loss on interest rate derivatives	0	0	(53,196)
Interest rate swaps | Reclassification out of Accumulated Other Comprehensive Income | Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest
Fair values of interest rate swap derivatives
Loss on interest rate derivatives	0	0	(51,865)
Interest rate swaps | Interest Expense
Fair values of interest rate swap derivatives
Amount of Loss Reclassified from AOCI/AOCL into Interest Expense on Statement of Operations	(996)	(5,048)	(3,725)
Undesignated Swaps
Fair values of interest rate swap derivatives
Loss on interest rate derivatives	$ 0	$ 0	$ (1,265)

Interest Rate Derivatives - Nar

Interest Rate Derivatives - Narrative (Details) $ in Thousands			1 Months Ended		12 Months Ended
	Jan. 28, 2022 USD ($)	Sep. 22, 2020 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Aug. 31, 2020 USD ($) derivative
Fair values of interest rate swap derivatives
Reclassification adjustments on interest rate derivatives					$ 0	$ 0	$ (51,865)
Payments for hedge, investing activities					$ 625	0	$ 53,130
2.25%, $400,000 aggregate principal | Unsecured Senior Notes
Fair values of interest rate swap derivatives
Interest rate					2.25%
Interest rate swap, effective September 1, 2016, swap three | Interest Expense
Fair values of interest rate swap derivatives
Reclassification adjustments on interest rate derivatives			$ (221)
Interest rate swap, effective September 1, 2016, swap three | Not Designated as Hedging Instrument
Fair values of interest rate swap derivatives
Notional amount of forecasted transaction not probable of occurring			$ 50,000			$ 50,000
Payments for hedge, investing activities	$ 625
Interest rate swaps
Fair values of interest rate swap derivatives
Notional amount of forecasted transaction not probable of occurring								$ 225,000
Number of interest rate derivatives discontinued due to forecasted transaction not probable of occurring | derivative								3
Payments for hedge, investing activities		$ 53,100
Interest rate swaps | Loss on Interest Rate Derivatives
Fair values of interest rate swap derivatives
Reclassification adjustments on interest rate derivatives				$ (51,900)
Interest rate swaps | Designated
Fair values of interest rate swap derivatives
Approximate amount to be reclassified from AOCL to interest expense over the next 12 months					$ 1,300

Redeemable Noncontrolling Int_3

Redeemable Noncontrolling Interests (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2022 USD ($) joint_venture	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Noncontrolling Interest [Abstract]
Number of joint ventures with redeemable noncontrolling interests | joint_venture	2
Redeemable Noncontrolling Interest [Roll Forward]
Beginning balance	$ 26,898	$ 25,430	$ 29,431
Distributions to noncontrolling interests	(2,976)	(3,307)	(14,034)
Net income attributable to noncontrolling interests	2,807	3,160	3,426
Adjustment to arrive at fair value of interests	(436)	1,615	6,607
Ending balance	$ 26,293	$ 26,898	$ 25,430

Equity - COPT and Subsidiaries

Equity - COPT and Subsidiaries (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Common Shares
Number of common shares for each converted common unit (in shares)		1	1	1
Number of operating partnerships units converted into common shares (in units)		0	8,054	14,009
Dividends declared per common share (in dollars per share)		$ 1.10	$ 1.10	$ 1.10
Preferred Shares
Preferred Stock
Number of preferred shares authorized		25,000,000
Number of preferred shares of beneficial interest authorized (in dollars per share)		$ 0.01
2022 ATM Program | Common Shares
Common Shares
At-market-stock, offering program established, aggregate value	$ 300
Shares issued to the public (in shares)		0

Share-Based Compensation and _3

Share-Based Compensation and Other Compensation Matters (Narrative) (Details) $ in Thousands							12 Months Ended
	Feb. 01, 2023 shares	Feb. 01, 2022 shares	Feb. 03, 2021 shares	Jan. 01, 2020 USD ($) shares	Jan. 01, 2019 USD ($) shares	Jan. 01, 2018 USD ($) shares	Dec. 31, 2022 USD ($) Percentile_Rank form shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) shares	May 31, 2017 shares
Executives and Non-Employee Trustees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated pre-vesting forfeitures							0%	0%	0%
All Other Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated pre-vesting forfeitures							8%	8%	8%
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $							$ 5,100
Expected weighted average period during which unrecognized compensation cost will be recognized							2 years
Aggregate intrinsic value of shares issued | $							$ 4,000	$ 4,300	$ 4,400
Number of common shares issued (in shares)							152,585	164,575	173,191
Stock awards granted (in shares or units)							186,515	177,995	166,918
PB-PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $							$ 3,700
Expected weighted average period during which unrecognized compensation cost will be recognized							2 years
Performance period of the award							3 years
Percentile ranks to fall between for PIUs | Percentile_Rank							2
Percent of award distribution rights							10%
TB- PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $							$ 3,000
Expected weighted average period during which unrecognized compensation cost will be recognized							2 years
Aggregate intrinsic value of shares issued | $							$ 2,000	$ 1,200	$ 640
Number of common shares issued (in shares)							77,709	45,244	25,182
Stock awards granted (in shares or units)							101,966	93,983	98,318
Deferred Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $							$ 85
Number of common shares issued (in shares)							0	0	0
Stock awards granted (in shares or units)							6,771	3,416	10,679
Grant Date Fair Value | $							$ 166	$ 93	$ 253
PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of forms of profit interest units | form							2
2017 Omnibus Equity and Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares of beneficial interest authorized to be issued										3,400,000
2019 PB PIU | PB-PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares/units issued for awards vested in period (in shares of units)		156,104
Stock awards granted (in shares or units)					193,682
Grant Date Fair Value | $					$ 2,415
2020 PB PIU | PB-PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)				176,758
Grant Date Fair Value | $				$ 2,891
2020 PB PIU | PB-PIUs | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares/units issued for awards vested in period (in shares of units)	141,152
2018 PSU Grants | PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period of the award							3 years
Shares/units issued for awards vested in period (in shares of units)			93,824
Stock awards granted (in shares or units)						59,110
Grant Date Fair Value | $						$ 1,900

Share-Based Compensation and _4

Share-Based Compensation and Other Compensation Matters (Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-Based Compensation
Share-based compensation cost	$ 9,637	$ 8,698	$ 7,060
General, administrative and leasing expenses
Share-Based Compensation
Share-based compensation cost	7,643	6,881	5,385
Property operating expenses
Share-Based Compensation
Share-based compensation cost	1,147	1,098	1,119
Capitalized to development activities
Share-Based Compensation
Share-based compensation cost	$ 847	$ 719	$ 556

Share-Based Compensation and _5

Share-Based Compensation and Other Compensation Matters (Restricted Shares and TB-PIUs Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Restricted shares
Shares
Unvested at the beginning of the period (in shares or units)	334,573	360,817	392,863
Stock awards granted (in shares or units)	186,515	177,995	166,918
Forfeited (in shares or units)	(43,420)	(39,664)	(25,773)
Vested (in shares or units)	(152,585)	(164,575)	(173,191)
Unvested at the end of the period (in shares or units)	325,083	334,573	360,817
Unvested shares as of December 31, 2022 that are expected to vest (in shares)	297,282
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share or unit)	$ 26.22	$ 26.16	$ 27.49
Grant date fair value (in dollars per share or unit)	26.50	26.17	25.22
Forfeited (in dollars per share or unit)	26.47	26.62	27.12
Vested (in dollars per share or unit)	26.39	25.95	28.14
Unvested at the end of the period (in dollars per share or unit)	26.27	$ 26.22	$ 26.16
Unvested shares as of December 31, 2022 that are expected to vest (in dollars per share or unit)	$ 26.25
TB- PIUs
Shares
Unvested at the beginning of the period (in shares or units)	163,073	114,334	61,820
Stock awards granted (in shares or units)	101,966	93,983	98,318
Forfeited (in shares or units)			(20,622)
Vested (in shares or units)	(77,709)	(45,244)	(25,182)
Unvested at the end of the period (in shares or units)	187,330	163,073	114,334
Unvested shares as of December 31, 2022 that are expected to vest (in shares)	186,345
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share or unit)	$ 25.99	$ 25.57	$ 26.01
Grant date fair value (in dollars per share or unit)	26.39	26.16	25.47
Forfeited (in dollars per share or unit)			25.50
Vested (in dollars per share or unit)	26.04	25.28	26.30
Unvested at the end of the period (in dollars per share or unit)	26.19	$ 25.99	$ 25.57
Unvested shares as of December 31, 2022 that are expected to vest (in dollars per share or unit)	$ 26.19

Share-Based Compensation and _6

Share-Based Compensation and Other Compensation Matters (Grants to Executives) (Details) - USD ($) $ in Thousands						12 Months Ended
	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020	Jan. 01, 2019	Jan. 01, 2018	Dec. 31, 2022
PSUs | 2018 PSU Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)					59,110
Grant Date Fair Value					$ 1,900
PB-PIUs | 2019 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)				193,682
Grant Date Fair Value				$ 2,415
Unvested at the end of the period (in shares or units)						0
PB-PIUs | 2020 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)			176,758
Grant Date Fair Value			$ 2,891
Unvested at the end of the period (in shares or units)						141,152
PB-PIUs | 2021 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)		227,544
Grant Date Fair Value		$ 3,417
Unvested at the end of the period (in shares or units)						227,544
PB-PIUs | 2022 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)	231,838
Grant Date Fair Value	$ 3,810
Unvested at the end of the period (in shares or units)						231,838

Share-Based Compensation and _7

Share-Based Compensation and Other Compensation Matters (Percentile Grant and Assumptions) (Details) - $ / shares				12 Months Ended
	Jan. 01, 2022	Jan. 01, 2021	Jan. 01, 2020	Dec. 31, 2022
PB-PIUs
Potential earned payout for defined levels of performance under awards
Earned payout (as a percent of PSUs/ PIUs granted) on 75th or greater percentile rank				100%
Earned payout (as a percent of PSUs/ PIUs granted) on 50th percentile rank (target)				50%
Earned payout (as a percent of PSUs/ PIUs granted) on 25th percentile rank				25%
Performance share units/ PB PIUs granted on percentile rank below 25th (as a percent)				0%
PB-PIUs | 2020 PB PIU
Assumptions used to value stock awards
Baseline Common Share Value (in dollars per share)			$ 29.38
Expected Volatility of Common Shares			18%
Risk-free Interest Rate			1.65%
PB-PIUs | 2020 PB PIU | Target Level
Assumptions used to value stock awards
Grant date fair value (in dollars per share or unit)			$ 32.71
PB-PIUs | 2021 PB PIU
Assumptions used to value stock awards
Baseline Common Share Value (in dollars per share)		$ 26.08
Expected Volatility of Common Shares		34.70%
Risk-free Interest Rate		0.18%
PB-PIUs | 2021 PB PIU | Target Level
Assumptions used to value stock awards
Grant date fair value (in dollars per share or unit)		$ 30.03
PB-PIUs | 2022 PB PIU
Assumptions used to value stock awards
Baseline Common Share Value (in dollars per share)	$ 27.97
Expected Volatility of Common Shares	31.70%
Risk-free Interest Rate	0.98%
PB-PIUs | 2022 PB PIU | Target Level
Assumptions used to value stock awards
Grant date fair value (in dollars per share or unit)	$ 32.87
PSUs
Potential earned payout for defined levels of performance under awards
Earned payout (as a percent of PSUs/ PIUs granted) on 75th or greater percentile rank				200%
Earned payout (as a percent of PSUs/ PIUs granted) on 50th percentile rank (target)				100%
Earned payout (as a percent of PSUs/ PIUs granted) on 25th percentile rank				50%
Performance share units/ PB PIUs granted on percentile rank below 25th (as a percent)				0%

Share-Based Compensation and _8

Share-Based Compensation and Other Compensation Matters (Deferred Share Awards) (Details) - Deferred Share Awards - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Deferred Share Awards Granted (in shares)	6,771	3,416	10,679
Grant Date Fair Value	$ 166	$ 93	$ 253
Grant Date Fair Value Per Share (in dollars per share or unit)	$ 24.50	$ 27.12	$ 23.68

Information by Business Segme_3

Information by Business Segment - Narrative (Details)	Mar. 31, 2022 property
Segment Reporting [Abstract]
Number of properties changing reportable segments	2

Information by Business Segme_4

Information by Business Segment (Segment Financial Information for Our Reportable Segments) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment financial information for real estate operations
Revenues from real estate operations	$ 739,030	$ 664,446	$ 582,354
UJV NOI allocable to COPT	4,327	4,029	6,951
Segment assets	4,257,275	4,262,452
Segment assets
Segment financial information for real estate operations
Segment assets	3,709,271	3,575,462
Real estate operations
Segment financial information for real estate operations
Revenues from real estate operations	586,378	587,060	538,725
Property operating expenses	(228,401)	(230,219)	(203,840)
UJV NOI allocable to COPT	4,327	4,029	6,951
NOI from real estate operations	362,304	360,870	341,836
Additions to long-lived assets	104,526	96,785	81,479
Transfers from non-operating properties	418,420	284,949	476,362
Real estate operations | Total Defense/IT Locations
Segment financial information for real estate operations
Revenues from real estate operations	517,755	486,795	451,387
Property operating expenses	(190,636)	(177,162)	(161,052)
UJV NOI allocable to COPT	4,327	4,029	6,951
NOI from real estate operations	331,446	313,662	297,286
Additions to long-lived assets	66,751	59,579	53,618
Transfers from non-operating properties	417,716	245,630	393,271
Real estate operations | Total Defense/IT Locations | Fort Meade/BW Corridor
Segment financial information for real estate operations
Revenues from real estate operations	273,790	262,120	254,197
Property operating expenses	(97,727)	(92,521)	(85,032)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	176,063	169,599	169,165
Additions to long-lived assets	48,443	45,647	31,295
Transfers from non-operating properties	69,771	70,514	21,859
Real estate operations | Total Defense/IT Locations | Northern Virginia Defense/IT
Segment financial information for real estate operations
Revenues from real estate operations	73,985	65,853	61,685
Property operating expenses	(26,635)	(24,785)	(22,996)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	47,350	41,068	38,689
Additions to long-lived assets	11,102	6,197	12,314
Transfers from non-operating properties	1,882	90,050	2,557
Real estate operations | Total Defense/IT Locations | Lackland Air Force Base
Segment financial information for real estate operations
Revenues from real estate operations	62,911	57,756	50,982
Property operating expenses	(32,301)	(30,535)	(29,055)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	30,610	27,221	21,927
Additions to long-lived assets	0	0	0
Transfers from non-operating properties	1,290	59,323	456
Real estate operations | Total Defense/IT Locations | Navy Support Locations
Segment financial information for real estate operations
Revenues from real estate operations	32,754	33,757	32,869
Property operating expenses	(14,001)	(13,617)	(12,655)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	18,753	20,140	20,214
Additions to long-lived assets	3,801	4,193	7,104
Transfers from non-operating properties	6,420	0	0
Real estate operations | Total Defense/IT Locations | Redstone Arsenal
Segment financial information for real estate operations
Revenues from real estate operations	38,593	35,727	22,515
Property operating expenses	(15,600)	(11,618)	(8,119)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	22,993	24,109	14,396
Additions to long-lived assets	3,405	3,542	2,905
Transfers from non-operating properties	158,831	22,739	138,122
Real estate operations | Total Defense/IT Locations | Data Center Shells
Segment financial information for real estate operations
Revenues from real estate operations	35,722	31,582	29,139
Property operating expenses	(4,372)	(4,086)	(3,195)
UJV NOI allocable to COPT	4,327	4,029	6,951
NOI from real estate operations	35,677	31,525	32,895
Additions to long-lived assets	0	0	0
Transfers from non-operating properties	179,522	3,004	230,277
Real estate operations | Regional Office
Segment financial information for real estate operations
Revenues from real estate operations	59,316	63,107	56,759
Property operating expenses	(31,712)	(31,056)	(27,469)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	27,604	32,051	29,290
Additions to long-lived assets	37,625	35,038	16,538
Transfers from non-operating properties	704	39,319	83,091
Real estate operations | Wholesale Data Center
Segment financial information for real estate operations
Revenues from real estate operations	1,980	30,490	27,011
Property operating expenses	(979)	(17,424)	(13,543)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	1,001	13,066	13,468
Additions to long-lived assets	(35)	1,680	10,856
Transfers from non-operating properties	0	0	0
Real estate operations | Other
Segment financial information for real estate operations
Revenues from real estate operations	7,327	6,668	3,568
Property operating expenses	(5,074)	(4,577)	(1,776)
UJV NOI allocable to COPT	0	0	0
NOI from real estate operations	2,253	2,091	1,792
Additions to long-lived assets	185	488	467
Transfers from non-operating properties	0	0	0
Real estate operations | Segment assets
Segment financial information for real estate operations
Segment assets	3,709,271	3,575,462	3,388,978
Real estate operations | Segment assets | Total Defense/IT Locations
Segment financial information for real estate operations
Segment assets	3,155,408	2,841,516	2,711,978
Real estate operations | Segment assets | Total Defense/IT Locations | Fort Meade/BW Corridor
Segment financial information for real estate operations
Segment assets	1,387,517	1,332,399	1,277,849
Real estate operations | Segment assets | Total Defense/IT Locations | Northern Virginia Defense/IT
Segment financial information for real estate operations
Segment assets	488,277	489,582	411,780
Real estate operations | Segment assets | Total Defense/IT Locations | Lackland Air Force Base
Segment financial information for real estate operations
Segment assets	194,481	198,200	142,137
Real estate operations | Segment assets | Total Defense/IT Locations | Navy Support Locations
Segment financial information for real estate operations
Segment assets	169,119	170,985	178,897
Real estate operations | Segment assets | Total Defense/IT Locations | Redstone Arsenal
Segment financial information for real estate operations
Segment assets	453,543	300,252	281,386
Real estate operations | Segment assets | Total Defense/IT Locations | Data Center Shells
Segment financial information for real estate operations
Segment assets	462,471	350,098	419,929
Real estate operations | Segment assets | Regional Office
Segment financial information for real estate operations
Segment assets	550,059	537,268	471,356
Real estate operations | Segment assets | Wholesale Data Center
Segment financial information for real estate operations
Segment assets	0	192,647	201,820
Real estate operations | Segment assets | Other
Segment financial information for real estate operations
Segment assets	$ 3,804	$ 4,031	$ 3,824

Information by Business Segme_5

Information by Business Segment (Reconciliation of Revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of segment revenues to total revenues
Construction contract and other service revenues	$ 154,632	$ 107,876	$ 70,640
Less: Revenues from discontinued operations (Note 4)	(1,980)	(30,490)	(27,011)
Total revenues	739,030	664,446	582,354
Operating Expenses [Abstract]
Less: Property operating expenses from discontinued operations (Note 4)	(971)	(16,842)	(13,044)
Total property operating expenses	227,430	213,377	190,796
Reconciliation of UJV NOI allocable to COPT to Equity Income in Unconsolidated entities [Abstract]
UJV NOI allocable to COPT	4,327	4,029	6,951
Less: Income from UJVs allocable to COPT attributable to depreciation and amortization expense, interest expense and gain on extinguishment of debt	(3,145)	(2,930)	(5,120)
Add: Equity in income (loss) of unconsolidated non-real estate entities	561	(6)	(6)
Equity in income of unconsolidated entities	1,743	1,093	1,825
Computation of net operating income from service operations
Construction contract and other service revenues	154,632	107,876	70,640
Construction contract and other service expenses	(149,963)	(104,053)	(67,615)
Real estate operations
Reconciliation of segment revenues to total revenues
Total revenues	586,378	587,060	538,725
Operating Expenses [Abstract]
Property operating expenses	228,401	230,219	203,840
Less: Property operating expenses from discontinued operations (Note 4)	(971)	(16,842)	(13,044)
Reconciliation of UJV NOI allocable to COPT to Equity Income in Unconsolidated entities [Abstract]
UJV NOI allocable to COPT	4,327	4,029	6,951
Service operations
Computation of net operating income from service operations
NOI from service operations	$ 4,669	$ 3,823	$ 3,025

Information by Business Segme_6

Information by Business Segment (NOI Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment financial information for real estate operations
Depreciation and other amortization associated with real estate operations	$ (141,230)	$ (137,543)	$ (126,503)
General, administrative and leasing expenses	(35,798)	(36,127)	(33,001)
Business development expenses and land carry costs	(3,193)	(4,647)	(4,473)
Impairment losses	0	0	(1,530)
Interest expense	(61,174)	(65,398)	(67,937)
Interest and other income	9,341	7,879	8,574
Credit loss (expense) recoveries	(271)	1,128	933
Gain on sales of real estate	19,250	65,590	30,209
Gain on sale of investment in unconsolidated real estate joint venture	0	0	29,416
Loss on early extinguishment of debt	(609)	(100,626)	(7,306)
Loss on interest rate derivatives	0	0	(53,196)
Equity in income of unconsolidated entities	1,743	1,093	1,825
UJV NOI allocable to COPT included in equity in income of unconsolidated entities	(4,327)	(4,029)	(6,951)
Income tax expense	(447)	(145)	(353)
Revenues from real estate operations from discontinued operations (Note 4)	(1,980)	(30,490)	(27,011)
Property operating expenses from discontinued operations (Note 4)	971	16,842	13,044
Income from continuing operations	149,249	78,220	100,601
Real estate operations
Segment financial information for real estate operations
NOI from real estate operations	362,304	360,870	341,836
UJV NOI allocable to COPT included in equity in income of unconsolidated entities	(4,327)	(4,029)	(6,951)
Property operating expenses from discontinued operations (Note 4)	971	16,842	13,044
Service operations
Segment financial information for real estate operations
NOI from service operations	$ 4,669	$ 3,823	$ 3,025

Information by Business Segme_7

Information by Business Segment (Assets Reconciliation) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Reconciliation of segment assets to total assets
Total consolidated assets	$ 4,257,275	$ 4,262,452
Operating properties lease liabilities included in segment assets	28,759	29,342
Segment assets
Reconciliation of segment assets to total assets
Total consolidated assets	3,709,271	3,575,462
Operating properties lease liabilities included in segment assets	28,759	29,342
Non-operating property assets
Reconciliation of segment assets to total assets
Total consolidated assets	301,002	449,144
Other assets
Reconciliation of segment assets to total assets
Total consolidated assets	$ 218,243	$ 208,504

Construction Contract and Oth_3

Construction Contract and Other Service Revenues (Construction Contract and Other Service Revenues by Compensation Arrangement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 154,632	$ 107,876	$ 70,640
Construction
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	151,694	104,020	66,087
Design
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	894	2,250	2,343
Other
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	2,044	1,606	2,210
GMP
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	129,149	68,113	22,032
FFP
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	15,119	13,897	12,373
Cost-plus fee
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	8,320	24,260	34,025
Other
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 2,044	$ 1,606	$ 2,210

Construction Contract and Oth_4

Construction Contract and Other Service Revenues (Percentage of Revenue - Narrative) (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Construction contract revenue | Revenue from Contract with Customer Benchmark | Concentration risk | United States Government
Concentration Risk [Line Items]
Percentage of revenue	90%	79%	55%

Construction Contract and Oth_5

Construction Contract and Other Service Revenues (Rollforwards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Change in Accounts Receivable
Beginning balance	$ 40,752
Ending balance	43,334	$ 40,752
Change in Contract with Customer, Asset
Beginning balance	22,384
Ending balance	22,331	22,384
Construction contract revenue
Change in Accounts Receivable
Beginning balance	7,193	13,997
Ending balance	7,618	7,193
Change in Contract with Customer, Asset
Beginning balance	22,384	10,343
Ending balance	22,331	22,384
Change in Contract with Customer, Liability
Beginning balance	2,499	4,610
Ending balance	2,867	2,499
Portion of beginning balance recognized in revenue during the year	$ 278	$ 2,664

Construction Contract and Oth_6

Construction Contract and Other Service Revenues (Narrative) (Details) - Construction contract revenue - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Remaining performance obligations	$ 67,900,000
Deferred incremental costs	0	$ 0
Credit loss (recoveries) expense	(740,000)	$ 211,000	$ 528,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Disaggregation of Revenue [Line Items]
Remaining performance obligations	$ 65,000,000
Expected timing	1 year

Credit Losses on Financial As_3

Credit Losses on Financial Assets and Other Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Off-Balance Sheet Credit Exposures [Roll Forward]
Beginning balance	$ 0	$ 0	$ 0
Cumulative effect of change for adoption of credit loss guidance			1,340
Credit loss (recoveries) expense	0	0	(1,340)
Other changes			0
Ending balance	0	0	0
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Beginning balance	3,569	4,697	97
Cumulative effect of change for adoption of credit loss guidance			5,541
Credit loss (recoveries) expense	271	(1,128)	(933)
Other changes			(8)
Ending balance	3,840	3,569	4,697
Other Assets
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	913	643	0
Cumulative effect of change for adoption of credit loss guidance			144
Credit loss (recoveries) expense	(645)	270	559
Other changes			(60)
Ending balance	268	913	643
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	268	913	643
Other Assets | Accounts Receivable, Net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	218
Ending balance	52	218
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	52	218
Other Assets | Prepaid expenses and other assets, net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	695
Ending balance	216	695
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	216	695
Investing Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,599	2,851	0
Cumulative effect of change for adoption of credit loss guidance			3,732
Credit loss (recoveries) expense	1,195	(1,252)	(881)
Other changes			0
Ending balance	2,794	1,599	2,851
Tenant Notes Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,057	1,203	97
Cumulative effect of change for adoption of credit loss guidance			325
Credit loss (recoveries) expense	(279)	(146)	729
Other changes			52
Ending balance	$ 778	$ 1,057	$ 1,203

Credit Losses on Financial As_4

Credit Losses on Financial Assets and Other Instruments (Credit Risk Classification) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Investing Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	$ 60,437
2018	0
2019	15
2020	1,887
2021	7,379
2022	17,697
Total	87,415	$ 83,825
Investing Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	60,437
2018	0
2019	0
2020	1,887
2021	7,379
2022	0
Total	69,703
Investing Receivables | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	0
2018	0
2019	15
2020	0
2021	0
2022	17,697
Total	17,712
Tenant Notes Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	151
2018	905
2019	129
2020	1,760
2021	0
2022	0
Total	2,945
Tenant Notes Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	0
2018	807
2019	40
2020	195
2021	0
2022	0
Total	1,042
Tenant Notes Receivables | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	151
2018	98
2019	89
2020	1,565
2021	0
2022	0
Total	1,903
Sales-Type Lease Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2017 and Earlier	0
2018	0
2019	0
2020	5,666
2021	0
2022	0
Total	$ 5,666

Earnings Per Share ("EPS") (Bas

Earnings Per Share ("EPS") (Basic and Diluted Calculation) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Numerator:
Income from continuing operations		$ 149,249	$ 78,220	$ 100,601
Income from continuing operations attributable to noncontrolling interests		(5,372)	(4,994)	(5,477)
Income from continuing operations attributable to share-based compensation awards for basic EPS		(451)	(467)	(433)
Numerator for basic EPS from continuing operations attributable to COPT common shareholders		143,426	72,759	94,691
Redeemable noncontrolling interests		(169)	(128)	0
Adjustment to income from continuing operations attributable to share-based compensation awards for diluted EPS		78	44	27
Numerator for diluted EPS from continuing operations attributable to COPT common shareholders		143,335	72,675	94,718
Discontinued operations		29,573	3,358	2,277
Discontinued operations attributable to noncontrolling interests		(421)	(43)	(27)
Income from discontinued operations attributable to share-based compensation awards for diluted EPS		(90)	6	2
Numerator for diluted EPS on net income attributable to COPT common shareholders		$ 172,397	$ 75,996	$ 96,970
Denominator (all weighted averages):
Denominator for basic EPS (common shares)		112,073	111,960	111,788
Dilutive effect of redeemable noncontrolling interests (common shares)		116	128	0
Dilutive effect of share-based compensation awards (common shares)		431	330	288
Denominator for diluted EPS (common shares)		112,620	112,418	112,076
Basic EPS:
Income from continuing operations attributable to COPT common shareholders - basic (in dollars per share)	[1]	$ 1.28	$ 0.65	$ 0.85
Discontinued operations attributable to COPT common shareholders - basic (in dollars per share)	[1]	0.26	0.03	0.02
Net income attributable to COPT common shareholders - basic (in dollars per share)	[1]	1.54	0.68	0.87
Diluted EPS:
Income from continuing operations attributable to COPT common shareholders - diluted (in dollars per share)	[1]	1.27	0.65	0.85
Discontinued operations attributable to COPT common shareholders - diluted (in dollars per share)		0.26	0.03	0.02
Net income attributable to COPT common shareholders - diluted (in dollars per share)	[1]	$ 1.53	$ 0.68	$ 0.87
[1]Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.

Earnings Per Share ("EPS") (Ant

Earnings Per Share ("EPS") (Anti-Dilutive Securities) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Conversion of common units
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	1,454	1,257	1,236
Conversion of redeemable noncontrolling interests
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	866	804	957
Conversion of Series I preferred units
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	0	0	171
Weighted average restricted shares and deferred share awards
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	399	412	430
Weighted average TB-PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	187	158	89

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Dec. 31, 2022 USD ($) property
Commitments and Contingencies
Estimate of possible loss	$ 4
Environmental Indemnity Agreement
Number of lease properties which were provided environmental indemnifications | property	3
Maximum environmental indemnification to the tenant against consequential damages after acquisition of property	$ 19
Anne Arundel County, Maryland | Tax Incremental Financing Bond
Environmental Indemnity Agreement
Maximum exposure	$ 29

Subsequent Events (Details)

Subsequent Events (Details) $ in Millions						12 Months Ended
	Jan. 10, 2023 USD ($) property	Dec. 14, 2022 USD ($) property	Dec. 30, 2021	Jun. 02, 2021 USD ($) property	Oct. 30, 2020 USD ($) property	Dec. 31, 2022 USD ($) property	Dec. 31, 2021 USD ($) property	Dec. 31, 2020 USD ($) property
Subsequent Event [Line Items]
Ownership percentage sold						90%	90%	90%
Number of properties sold | property						2	2	2
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]			Gain on sales of real estate			Gain on sales of real estate	Gain on sales of real estate	Gain on sales of real estate
Data Center Shells in Northern Virginia | Disposed of by sale
Subsequent Event [Line Items]
Ownership percentage sold		90%		90%	90%
Number of properties sold | property		2		2	2
Transaction value		$ 67		$ 118.8	$ 89.7
Proceeds from sale		$ 60.3		$ 106.9	$ 80.7
Gain on disposal						$ 19.2	$ 40.2	$ 30
Subsequent Event
Subsequent Event [Line Items]
Disposal Group, Not Discontinued Operation, Gain (Loss) on Disposal, Statement of Income or Comprehensive Income [Extensible Enumeration]	Gain on sales of real estate
Subsequent Event | Redshift JV LLC
Subsequent Event [Line Items]
Nominal Ownership %	10%
Subsequent Event | Data Center Shells in Northern Virginia | Disposed of by sale
Subsequent Event [Line Items]
Ownership percentage sold	90%
Number of properties sold | property	3
Transaction value	$ 211.3
Proceeds from sale	190.2
Gain on disposal	$ 49

Schedule III - Real Estate an_2

Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Real Estate and Accumulated Depreciation
Encumbrances	$ 118,293
Initial Cost
Land	709,752
Building and Land Improvements	3,606,680
Costs Capitalized Subsequent to Acquisition	670,105
Gross Amounts Carried At Close of Period
Land	709,752
Building and Land Improvements	4,276,785
Total	4,986,537	$ 4,959,709	$ 4,686,802	$ 4,348,006
Accumulated Depreciation	(1,273,448)	(1,234,908)	$ (1,124,253)	$ (1,007,120)
Additional information
Debt, net	2,231,794	2,272,304
Net discounts and deferred financing costs	23,200
Aggregate cost of assets for federal income tax purposes	$ 3,700,000
Buildings improvements | Minimum
Additional information
Estimated lives over which depreciation is recognized	10 years
Buildings improvements | Maximum
Additional information
Estimated lives over which depreciation is recognized	40 years
Revolving Credit Facility
Additional information
Debt, net	$ 211,000	76,000
Term Loan Facility
Additional information
Debt, net	123,948	$ 299,420
Unsecured Senior Notes
Additional information
Debt, net	1,800,000
Unsecured notes payable
Additional information
Debt, net	597
Fixed rate mortgage loans
Additional information
Net discounts and deferred financing costs	541
100 Light Street
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	26,715
Building and Land Improvements	58,002
Costs Capitalized Subsequent to Acquisition	45,315
Gross Amounts Carried At Close of Period
Land	26,715
Building and Land Improvements	103,317
Total	130,032
Accumulated Depreciation	(30,601)
100 Secured Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	71,159
Costs Capitalized Subsequent to Acquisition	34
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	71,193
Total	71,193
Accumulated Depreciation	(4,121)
1000 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	8,880
Initial Cost
Land	0
Building and Land Improvements	20,533
Costs Capitalized Subsequent to Acquisition	108
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	20,641
Total	20,641
Accumulated Depreciation	(5,045)
1100 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	9,547
Initial Cost
Land	0
Building and Land Improvements	19,593
Costs Capitalized Subsequent to Acquisition	100
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	19,693
Total	19,693
Accumulated Depreciation	(4,408)
114 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	364
Building and Land Improvements	3,109
Costs Capitalized Subsequent to Acquisition	427
Gross Amounts Carried At Close of Period
Land	364
Building and Land Improvements	3,536
Total	3,900
Accumulated Depreciation	(1,779)
1200 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	11,012
Initial Cost
Land	0
Building and Land Improvements	22,389
Costs Capitalized Subsequent to Acquisition	121
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	22,510
Total	22,510
Accumulated Depreciation	(5,077)
1201 M Street SE
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	49,775
Costs Capitalized Subsequent to Acquisition	10,384
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	60,159
Total	60,159
Accumulated Depreciation	(23,155)
1201 Winterson Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,130
Building and Land Improvements	17,202
Costs Capitalized Subsequent to Acquisition	924
Gross Amounts Carried At Close of Period
Land	2,130
Building and Land Improvements	18,126
Total	20,256
Accumulated Depreciation	(6,403)
1220 12th Street, SE
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	42,464
Costs Capitalized Subsequent to Acquisition	9,919
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	52,383
Total	52,383
Accumulated Depreciation	(21,522)
1243 Winterson Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	630
Building and Land Improvements	0
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	630
Building and Land Improvements	0
Total	630
Accumulated Depreciation	0
131 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,906
Building and Land Improvements	7,623
Costs Capitalized Subsequent to Acquisition	6,392
Gross Amounts Carried At Close of Period
Land	1,906
Building and Land Improvements	14,015
Total	15,921
Accumulated Depreciation	(8,472)
132 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,917
Building and Land Improvements	12,259
Costs Capitalized Subsequent to Acquisition	4,984
Gross Amounts Carried At Close of Period
Land	2,917
Building and Land Improvements	17,243
Total	20,160
Accumulated Depreciation	(11,464)
133 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,517
Building and Land Improvements	10,068
Costs Capitalized Subsequent to Acquisition	6,733
Gross Amounts Carried At Close of Period
Land	2,517
Building and Land Improvements	16,801
Total	19,318
Accumulated Depreciation	(11,461)
134 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,684
Building and Land Improvements	7,517
Costs Capitalized Subsequent to Acquisition	5,958
Gross Amounts Carried At Close of Period
Land	3,684
Building and Land Improvements	13,475
Total	17,159
Accumulated Depreciation	(8,950)
1340 Ashton Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	905
Building and Land Improvements	3,620
Costs Capitalized Subsequent to Acquisition	2,631
Gross Amounts Carried At Close of Period
Land	905
Building and Land Improvements	6,251
Total	7,156
Accumulated Depreciation	(3,639)
13450 Sunrise Valley Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,386
Building and Land Improvements	5,576
Costs Capitalized Subsequent to Acquisition	4,955
Gross Amounts Carried At Close of Period
Land	1,386
Building and Land Improvements	10,531
Total	11,917
Accumulated Depreciation	(7,040)
13454 Sunrise Valley Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,847
Building and Land Improvements	11,986
Costs Capitalized Subsequent to Acquisition	10,345
Gross Amounts Carried At Close of Period
Land	2,847
Building and Land Improvements	22,331
Total	25,178
Accumulated Depreciation	(13,637)
135 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,484
Building and Land Improvements	9,750
Costs Capitalized Subsequent to Acquisition	7,085
Gross Amounts Carried At Close of Period
Land	2,484
Building and Land Improvements	16,835
Total	19,319
Accumulated Depreciation	(11,512)
1362 Mellon Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	950
Building and Land Improvements	3,864
Costs Capitalized Subsequent to Acquisition	1,953
Gross Amounts Carried At Close of Period
Land	950
Building and Land Improvements	5,817
Total	6,767
Accumulated Depreciation	(1,577)
13857 McLearen Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,507
Building and Land Improvements	30,177
Costs Capitalized Subsequent to Acquisition	5,715
Gross Amounts Carried At Close of Period
Land	3,507
Building and Land Improvements	35,892
Total	39,399
Accumulated Depreciation	(14,907)
140 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,407
Building and Land Improvements	24,167
Costs Capitalized Subsequent to Acquisition	1,811
Gross Amounts Carried At Close of Period
Land	3,407
Building and Land Improvements	25,978
Total	29,385
Accumulated Depreciation	(12,361)
141 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,398
Building and Land Improvements	9,538
Costs Capitalized Subsequent to Acquisition	4,832
Gross Amounts Carried At Close of Period
Land	2,398
Building and Land Improvements	14,370
Total	16,768
Accumulated Depreciation	(10,153)
14280 Park Meadow Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,731
Building and Land Improvements	15,953
Costs Capitalized Subsequent to Acquisition	5,621
Gross Amounts Carried At Close of Period
Land	3,731
Building and Land Improvements	21,574
Total	25,305
Accumulated Depreciation	(11,413)
1460 Dorsey Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,577
Building and Land Improvements	183
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,577
Building and Land Improvements	183
Total	1,760
Accumulated Depreciation	0
14840 Conference Center Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,572
Building and Land Improvements	8,175
Costs Capitalized Subsequent to Acquisition	5,728
Gross Amounts Carried At Close of Period
Land	1,572
Building and Land Improvements	13,903
Total	15,475
Accumulated Depreciation	(8,420)
14850 Conference Center Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,615
Building and Land Improvements	8,358
Costs Capitalized Subsequent to Acquisition	7,439
Gross Amounts Carried At Close of Period
Land	1,615
Building and Land Improvements	15,797
Total	17,412
Accumulated Depreciation	(8,032)
14900 Conference Center Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,436
Building and Land Improvements	14,402
Costs Capitalized Subsequent to Acquisition	9,371
Gross Amounts Carried At Close of Period
Land	3,436
Building and Land Improvements	23,773
Total	27,209
Accumulated Depreciation	(14,901)
1501 South Clinton Street
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	27,964
Building and Land Improvements	51,990
Costs Capitalized Subsequent to Acquisition	44,816
Gross Amounts Carried At Close of Period
Land	27,964
Building and Land Improvements	96,806
Total	124,770
Accumulated Depreciation	(34,787)
15049 Conference Center Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	4,415
Building and Land Improvements	20,365
Costs Capitalized Subsequent to Acquisition	17,846
Gross Amounts Carried At Close of Period
Land	4,415
Building and Land Improvements	38,211
Total	42,626
Accumulated Depreciation	(22,574)
15059 Conference Center Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	5,753
Building and Land Improvements	13,615
Costs Capitalized Subsequent to Acquisition	6,313
Gross Amounts Carried At Close of Period
Land	5,753
Building and Land Improvements	19,928
Total	25,681
Accumulated Depreciation	(11,364)
1550 West Nursery Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	14,071
Building and Land Improvements	16,930
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	14,071
Building and Land Improvements	16,930
Total	31,001
Accumulated Depreciation	(7,047)
1560 West Nursery Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,441
Building and Land Improvements	113
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,441
Building and Land Improvements	113
Total	1,554
Accumulated Depreciation	(24)
1610 West Nursery Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	259
Building and Land Improvements	246
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	259
Building and Land Improvements	246
Total	505
Accumulated Depreciation	(36)
1616 West Nursery Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	393
Building and Land Improvements	3,323
Costs Capitalized Subsequent to Acquisition	75
Gross Amounts Carried At Close of Period
Land	393
Building and Land Improvements	3,398
Total	3,791
Accumulated Depreciation	(449)
1622 West Nursery Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	393
Building and Land Improvements	2,542
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	393
Building and Land Improvements	2,542
Total	2,935
Accumulated Depreciation	(372)
16442 Commerce Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	613
Building and Land Improvements	2,582
Costs Capitalized Subsequent to Acquisition	1,147
Gross Amounts Carried At Close of Period
Land	613
Building and Land Improvements	3,729
Total	4,342
Accumulated Depreciation	(2,134)
16480 Commerce Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,856
Building and Land Improvements	7,425
Costs Capitalized Subsequent to Acquisition	2,772
Gross Amounts Carried At Close of Period
Land	1,856
Building and Land Improvements	10,197
Total	12,053
Accumulated Depreciation	(5,203)
16501 Commerce Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	522
Building and Land Improvements	2,090
Costs Capitalized Subsequent to Acquisition	1,040
Gross Amounts Carried At Close of Period
Land	522
Building and Land Improvements	3,130
Total	3,652
Accumulated Depreciation	(1,689)
16539 Commerce Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	688
Building and Land Improvements	2,860
Costs Capitalized Subsequent to Acquisition	2,345
Gross Amounts Carried At Close of Period
Land	688
Building and Land Improvements	5,205
Total	5,893
Accumulated Depreciation	(3,190)
16541 Commerce Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	773
Building and Land Improvements	3,094
Costs Capitalized Subsequent to Acquisition	2,630
Gross Amounts Carried At Close of Period
Land	773
Building and Land Improvements	5,724
Total	6,497
Accumulated Depreciation	(3,261)
16543 Commerce Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	436
Building and Land Improvements	1,742
Costs Capitalized Subsequent to Acquisition	879
Gross Amounts Carried At Close of Period
Land	436
Building and Land Improvements	2,621
Total	3,057
Accumulated Depreciation	(1,467)
1751 Pinnacle Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	10,486
Building and Land Improvements	42,339
Costs Capitalized Subsequent to Acquisition	34,512
Gross Amounts Carried At Close of Period
Land	10,486
Building and Land Improvements	76,851
Total	87,337
Accumulated Depreciation	(45,785)
1753 Pinnacle Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	8,275
Building and Land Improvements	34,353
Costs Capitalized Subsequent to Acquisition	25,142
Gross Amounts Carried At Close of Period
Land	8,275
Building and Land Improvements	59,495
Total	67,770
Accumulated Depreciation	(30,720)
206 Research Boulevard
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	0
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	0
Total	0
Accumulated Depreciation	0
209 Research Boulevard
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	134
Building and Land Improvements	1,711
Costs Capitalized Subsequent to Acquisition	543
Gross Amounts Carried At Close of Period
Land	134
Building and Land Improvements	2,254
Total	2,388
Accumulated Depreciation	(772)
210 Research Boulevard
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	113
Building and Land Improvements	1,402
Costs Capitalized Subsequent to Acquisition	536
Gross Amounts Carried At Close of Period
Land	113
Building and Land Improvements	1,938
Total	2,051
Accumulated Depreciation	(610)
2100 L Street
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	57,385
Building and Land Improvements	94,784
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	57,385
Building and Land Improvements	94,784
Total	152,169
Accumulated Depreciation	(4,385)
2100 Rideout Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	7,336
Costs Capitalized Subsequent to Acquisition	3,015
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	10,351
Total	10,351
Accumulated Depreciation	(2,760)
22289 Exploration Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,422
Building and Land Improvements	5,719
Costs Capitalized Subsequent to Acquisition	2,148
Gross Amounts Carried At Close of Period
Land	1,422
Building and Land Improvements	7,867
Total	9,289
Accumulated Depreciation	(4,585)
22299 Exploration Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,362
Building and Land Improvements	5,791
Costs Capitalized Subsequent to Acquisition	3,084
Gross Amounts Carried At Close of Period
Land	1,362
Building and Land Improvements	8,875
Total	10,237
Accumulated Depreciation	(5,531)
22300 Exploration Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,094
Building and Land Improvements	5,038
Costs Capitalized Subsequent to Acquisition	2,772
Gross Amounts Carried At Close of Period
Land	1,094
Building and Land Improvements	7,810
Total	8,904
Accumulated Depreciation	(4,640)
22309 Exploration Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,243
Building and Land Improvements	10,419
Costs Capitalized Subsequent to Acquisition	8,179
Gross Amounts Carried At Close of Period
Land	2,243
Building and Land Improvements	18,598
Total	20,841
Accumulated Depreciation	(9,668)
23535 Cottonwood Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	692
Building and Land Improvements	3,051
Costs Capitalized Subsequent to Acquisition	648
Gross Amounts Carried At Close of Period
Land	692
Building and Land Improvements	3,699
Total	4,391
Accumulated Depreciation	(2,358)
250 W Pratt St
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	8,057
Building and Land Improvements	34,588
Costs Capitalized Subsequent to Acquisition	19,811
Gross Amounts Carried At Close of Period
Land	8,057
Building and Land Improvements	54,399
Total	62,456
Accumulated Depreciation	(22,224)
2600 Park Tower Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	20,284
Building and Land Improvements	34,443
Costs Capitalized Subsequent to Acquisition	5,977
Gross Amounts Carried At Close of Period
Land	20,284
Building and Land Improvements	40,420
Total	60,704
Accumulated Depreciation	(9,764)
2691 Technology Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,098
Building and Land Improvements	17,334
Costs Capitalized Subsequent to Acquisition	9,191
Gross Amounts Carried At Close of Period
Land	2,098
Building and Land Improvements	26,525
Total	28,623
Accumulated Depreciation	(13,031)
2701 Technology Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,737
Building and Land Improvements	15,266
Costs Capitalized Subsequent to Acquisition	7,118
Gross Amounts Carried At Close of Period
Land	1,737
Building and Land Improvements	22,384
Total	24,121
Accumulated Depreciation	(14,080)
2711 Technology Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,251
Building and Land Improvements	21,611
Costs Capitalized Subsequent to Acquisition	4,459
Gross Amounts Carried At Close of Period
Land	2,251
Building and Land Improvements	26,070
Total	28,321
Accumulated Depreciation	(16,361)
2720 Technology Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,863
Building and Land Improvements	29,272
Costs Capitalized Subsequent to Acquisition	3,219
Gross Amounts Carried At Close of Period
Land	3,863
Building and Land Improvements	32,491
Total	36,354
Accumulated Depreciation	(15,238)
2721 Technology Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	4,611
Building and Land Improvements	14,597
Costs Capitalized Subsequent to Acquisition	3,828
Gross Amounts Carried At Close of Period
Land	4,611
Building and Land Improvements	18,425
Total	23,036
Accumulated Depreciation	(11,406)
2730 Hercules Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	8,737
Building and Land Improvements	31,612
Costs Capitalized Subsequent to Acquisition	9,540
Gross Amounts Carried At Close of Period
Land	8,737
Building and Land Improvements	41,152
Total	49,889
Accumulated Depreciation	(25,143)
30 Light Street
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	12,101
Costs Capitalized Subsequent to Acquisition	1,056
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	13,157
Total	13,157
Accumulated Depreciation	(2,742)
300 Secured Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	25,384
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	25,384
Total	25,384
Accumulated Depreciation	0
300 Sentinel Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,517
Building and Land Improvements	59,165
Costs Capitalized Subsequent to Acquisition	2,526
Gross Amounts Carried At Close of Period
Land	1,517
Building and Land Improvements	61,691
Total	63,208
Accumulated Depreciation	(20,225)
302 Sentinel Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,648
Building and Land Improvements	29,687
Costs Capitalized Subsequent to Acquisition	3,802
Gross Amounts Carried At Close of Period
Land	2,648
Building and Land Improvements	33,489
Total	36,137
Accumulated Depreciation	(12,102)
304 Sentinel Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,411
Building and Land Improvements	24,917
Costs Capitalized Subsequent to Acquisition	5,335
Gross Amounts Carried At Close of Period
Land	3,411
Building and Land Improvements	30,252
Total	33,663
Accumulated Depreciation	(13,355)
306 Sentinel Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,260
Building and Land Improvements	22,592
Costs Capitalized Subsequent to Acquisition	3,720
Gross Amounts Carried At Close of Period
Land	3,260
Building and Land Improvements	26,312
Total	29,572
Accumulated Depreciation	(11,085)
308 Sentinel Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,422
Building and Land Improvements	26,208
Costs Capitalized Subsequent to Acquisition	2,365
Gross Amounts Carried At Close of Period
Land	1,422
Building and Land Improvements	28,573
Total	29,995
Accumulated Depreciation	(8,761)
310 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,372
Building and Land Improvements	43,312
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	2,372
Building and Land Improvements	43,312
Total	45,684
Accumulated Depreciation	(7,180)
310 The Bridge Street
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	261
Building and Land Improvements	26,530
Costs Capitalized Subsequent to Acquisition	5,958
Gross Amounts Carried At Close of Period
Land	261
Building and Land Improvements	32,488
Total	32,749
Accumulated Depreciation	(13,337)
312 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,138
Building and Land Improvements	27,797
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	3,138
Building and Land Improvements	27,797
Total	30,935
Accumulated Depreciation	(5,779)
314 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,254
Building and Land Improvements	7,741
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,254
Building and Land Improvements	7,741
Total	8,995
Accumulated Depreciation	(1,713)
316 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,748
Building and Land Improvements	38,156
Costs Capitalized Subsequent to Acquisition	225
Gross Amounts Carried At Close of Period
Land	2,748
Building and Land Improvements	38,381
Total	41,129
Accumulated Depreciation	(10,394)
318 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,185
Building and Land Improvements	28,426
Costs Capitalized Subsequent to Acquisition	562
Gross Amounts Carried At Close of Period
Land	2,185
Building and Land Improvements	28,988
Total	31,173
Accumulated Depreciation	(12,249)
320 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,067
Building and Land Improvements	21,623
Costs Capitalized Subsequent to Acquisition	156
Gross Amounts Carried At Close of Period
Land	2,067
Building and Land Improvements	21,779
Total	23,846
Accumulated Depreciation	(8,206)
322 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,605
Building and Land Improvements	22,827
Costs Capitalized Subsequent to Acquisition	1,900
Gross Amounts Carried At Close of Period
Land	2,605
Building and Land Improvements	24,727
Total	27,332
Accumulated Depreciation	(10,090)
324 Sentinel Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,656
Building and Land Improvements	23,018
Costs Capitalized Subsequent to Acquisition	42
Gross Amounts Carried At Close of Period
Land	1,656
Building and Land Improvements	23,060
Total	24,716
Accumulated Depreciation	(7,109)
4000 Market Street
Real Estate and Accumulated Depreciation
Encumbrances	5,993
Initial Cost
Land	0
Building and Land Improvements	9,198
Costs Capitalized Subsequent to Acquisition	396
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	9,594
Total	9,594
Accumulated Depreciation	(858)
410 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,831
Building and Land Improvements	23,257
Costs Capitalized Subsequent to Acquisition	2,259
Gross Amounts Carried At Close of Period
Land	1,831
Building and Land Improvements	25,516
Total	27,347
Accumulated Depreciation	(7,048)
4100 Market Street
Real Estate and Accumulated Depreciation
Encumbrances	5,217
Initial Cost
Land	0
Building and Land Improvements	8,049
Costs Capitalized Subsequent to Acquisition	7
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	8,056
Total	8,056
Accumulated Depreciation	(710)
420 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,370
Building and Land Improvements	29,550
Costs Capitalized Subsequent to Acquisition	208
Gross Amounts Carried At Close of Period
Land	2,370
Building and Land Improvements	29,758
Total	32,128
Accumulated Depreciation	(6,217)
430 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,852
Building and Land Improvements	21,563
Costs Capitalized Subsequent to Acquisition	2,950
Gross Amounts Carried At Close of Period
Land	1,852
Building and Land Improvements	24,513
Total	26,365
Accumulated Depreciation	(6,632)
44408 Pecan Court
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	817
Building and Land Improvements	1,583
Costs Capitalized Subsequent to Acquisition	1,751
Gross Amounts Carried At Close of Period
Land	817
Building and Land Improvements	3,334
Total	4,151
Accumulated Depreciation	(2,259)
44414 Pecan Court
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	405
Building and Land Improvements	1,619
Costs Capitalized Subsequent to Acquisition	1,149
Gross Amounts Carried At Close of Period
Land	405
Building and Land Improvements	2,768
Total	3,173
Accumulated Depreciation	(1,861)
44417 Pecan Court
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	434
Building and Land Improvements	3,822
Costs Capitalized Subsequent to Acquisition	180
Gross Amounts Carried At Close of Period
Land	434
Building and Land Improvements	4,002
Total	4,436
Accumulated Depreciation	(2,385)
44420 Pecan Court
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	344
Building and Land Improvements	890
Costs Capitalized Subsequent to Acquisition	311
Gross Amounts Carried At Close of Period
Land	344
Building and Land Improvements	1,201
Total	1,545
Accumulated Depreciation	(667)
44425 Pecan Court
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,309
Building and Land Improvements	3,506
Costs Capitalized Subsequent to Acquisition	2,395
Gross Amounts Carried At Close of Period
Land	1,309
Building and Land Improvements	5,901
Total	7,210
Accumulated Depreciation	(4,076)
45310 Abell House Lane
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,272
Building and Land Improvements	13,808
Costs Capitalized Subsequent to Acquisition	1,386
Gross Amounts Carried At Close of Period
Land	2,272
Building and Land Improvements	15,194
Total	17,466
Accumulated Depreciation	(4,357)
4600 River Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	24,573
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	24,573
Total	24,573
Accumulated Depreciation	(1,049)
46579 Expedition Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,406
Building and Land Improvements	5,796
Costs Capitalized Subsequent to Acquisition	2,987
Gross Amounts Carried At Close of Period
Land	1,406
Building and Land Improvements	8,783
Total	10,189
Accumulated Depreciation	(4,897)
46591 Expedition Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,200
Building and Land Improvements	7,199
Costs Capitalized Subsequent to Acquisition	4,394
Gross Amounts Carried At Close of Period
Land	1,200
Building and Land Improvements	11,593
Total	12,793
Accumulated Depreciation	(5,181)
4851 Stonecroft Boulevard
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,878
Building and Land Improvements	11,558
Costs Capitalized Subsequent to Acquisition	223
Gross Amounts Carried At Close of Period
Land	1,878
Building and Land Improvements	11,781
Total	13,659
Accumulated Depreciation	(5,307)
540 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,035
Building and Land Improvements	31,840
Costs Capitalized Subsequent to Acquisition	41
Gross Amounts Carried At Close of Period
Land	2,035
Building and Land Improvements	31,881
Total	33,916
Accumulated Depreciation	(4,124)
550 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,678
Building and Land Improvements	30,363
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	2,678
Building and Land Improvements	30,363
Total	33,041
Accumulated Depreciation	0
5520 Research Park Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	20,072
Costs Capitalized Subsequent to Acquisition	1,979
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	22,051
Total	22,051
Accumulated Depreciation	(7,741)
5522 Research Park Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	4,550
Costs Capitalized Subsequent to Acquisition	855
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	5,405
Total	5,405
Accumulated Depreciation	(2,050)
560 National Business Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,193
Building and Land Improvements	55,149
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	2,193
Building and Land Improvements	55,149
Total	57,342
Accumulated Depreciation	(233)
5801 University Research Court
Real Estate and Accumulated Depreciation
Encumbrances	10,880
Initial Cost
Land	0
Building and Land Improvements	17,431
Costs Capitalized Subsequent to Acquisition	162
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	17,593
Total	17,593
Accumulated Depreciation	(2,294)
5825 University Research Court
Real Estate and Accumulated Depreciation
Encumbrances	19,075
Initial Cost
Land	0
Building and Land Improvements	22,771
Costs Capitalized Subsequent to Acquisition	2,517
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	25,288
Total	25,288
Accumulated Depreciation	(8,978)
5850 University Research Court
Real Estate and Accumulated Depreciation
Encumbrances	20,182
Initial Cost
Land	0
Building and Land Improvements	31,906
Costs Capitalized Subsequent to Acquisition	1,112
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	33,018
Total	33,018
Accumulated Depreciation	(10,623)
6000 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	8,532
Costs Capitalized Subsequent to Acquisition	17
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	8,549
Total	8,549
Accumulated Depreciation	(415)
610 Guardian Way
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	7,636
Building and Land Improvements	53,574
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	7,636
Building and Land Improvements	53,574
Total	61,210
Accumulated Depreciation	(1,572)
6200 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	38,479
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	38,479
Total	38,479
Accumulated Depreciation	0
6700 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,755
Building and Land Improvements	7,019
Costs Capitalized Subsequent to Acquisition	10,504
Gross Amounts Carried At Close of Period
Land	1,755
Building and Land Improvements	17,523
Total	19,278
Accumulated Depreciation	(10,285)
6708 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	897
Building and Land Improvements	12,693
Costs Capitalized Subsequent to Acquisition	1,618
Gross Amounts Carried At Close of Period
Land	897
Building and Land Improvements	14,311
Total	15,208
Accumulated Depreciation	(5,238)
6711 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,683
Building and Land Improvements	23,239
Costs Capitalized Subsequent to Acquisition	2,885
Gross Amounts Carried At Close of Period
Land	2,683
Building and Land Improvements	26,124
Total	28,807
Accumulated Depreciation	(10,779)
6716 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,242
Building and Land Improvements	4,969
Costs Capitalized Subsequent to Acquisition	5,323
Gross Amounts Carried At Close of Period
Land	1,242
Building and Land Improvements	10,292
Total	11,534
Accumulated Depreciation	(6,718)
6721 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,753
Building and Land Improvements	34,090
Costs Capitalized Subsequent to Acquisition	9,263
Gross Amounts Carried At Close of Period
Land	1,753
Building and Land Improvements	43,353
Total	45,106
Accumulated Depreciation	(13,231)
6724 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	449
Building and Land Improvements	5,039
Costs Capitalized Subsequent to Acquisition	2,491
Gross Amounts Carried At Close of Period
Land	449
Building and Land Improvements	7,530
Total	7,979
Accumulated Depreciation	(4,349)
6731 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,807
Building and Land Improvements	19,098
Costs Capitalized Subsequent to Acquisition	6,351
Gross Amounts Carried At Close of Period
Land	2,807
Building and Land Improvements	25,449
Total	28,256
Accumulated Depreciation	(14,983)
6740 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,424
Building and Land Improvements	4,209
Costs Capitalized Subsequent to Acquisition	7,131
Gross Amounts Carried At Close of Period
Land	1,424
Building and Land Improvements	11,340
Total	12,764
Accumulated Depreciation	(2,773)
6741 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	675
Building and Land Improvements	1,711
Costs Capitalized Subsequent to Acquisition	176
Gross Amounts Carried At Close of Period
Land	675
Building and Land Improvements	1,887
Total	2,562
Accumulated Depreciation	(762)
6750 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,263
Building and Land Improvements	12,461
Costs Capitalized Subsequent to Acquisition	6,050
Gross Amounts Carried At Close of Period
Land	1,263
Building and Land Improvements	18,511
Total	19,774
Accumulated Depreciation	(11,751)
6760 Alexander Bell Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	890
Building and Land Improvements	3,561
Costs Capitalized Subsequent to Acquisition	3,915
Gross Amounts Carried At Close of Period
Land	890
Building and Land Improvements	7,476
Total	8,366
Accumulated Depreciation	(5,348)
6940 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,545
Building and Land Improvements	9,916
Costs Capitalized Subsequent to Acquisition	12,340
Gross Amounts Carried At Close of Period
Land	3,545
Building and Land Improvements	22,256
Total	25,801
Accumulated Depreciation	(12,733)
6950 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,596
Building and Land Improvements	28,307
Costs Capitalized Subsequent to Acquisition	3,223
Gross Amounts Carried At Close of Period
Land	3,596
Building and Land Improvements	31,530
Total	35,126
Accumulated Depreciation	(13,441)
7000 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,131
Building and Land Improvements	12,103
Costs Capitalized Subsequent to Acquisition	10,451
Gross Amounts Carried At Close of Period
Land	3,131
Building and Land Improvements	22,554
Total	25,685
Accumulated Depreciation	(11,944)
7000 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	7,542
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	7,542
Total	7,542
Accumulated Depreciation	0
7005 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,036
Building and Land Improvements	747
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	3,036
Building and Land Improvements	747
Total	3,783
Accumulated Depreciation	0
7015 Albert Einstein Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,058
Building and Land Improvements	6,093
Costs Capitalized Subsequent to Acquisition	3,560
Gross Amounts Carried At Close of Period
Land	2,058
Building and Land Improvements	9,653
Total	11,711
Accumulated Depreciation	(5,447)
7061 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	729
Building and Land Improvements	3,094
Costs Capitalized Subsequent to Acquisition	2,909
Gross Amounts Carried At Close of Period
Land	729
Building and Land Improvements	6,003
Total	6,732
Accumulated Depreciation	(3,806)
7063 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	902
Building and Land Improvements	3,684
Costs Capitalized Subsequent to Acquisition	3,470
Gross Amounts Carried At Close of Period
Land	902
Building and Land Improvements	7,154
Total	8,056
Accumulated Depreciation	(4,975)
7065 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	919
Building and Land Improvements	3,763
Costs Capitalized Subsequent to Acquisition	3,174
Gross Amounts Carried At Close of Period
Land	919
Building and Land Improvements	6,937
Total	7,856
Accumulated Depreciation	(4,846)
7067 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,829
Building and Land Improvements	11,823
Costs Capitalized Subsequent to Acquisition	8,125
Gross Amounts Carried At Close of Period
Land	1,829
Building and Land Improvements	19,948
Total	21,777
Accumulated Depreciation	(10,234)
7100 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	12,983
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	12,983
Total	12,983
Accumulated Depreciation	(514)
7125 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	20,487
Building and Land Improvements	49,925
Costs Capitalized Subsequent to Acquisition	27,278
Gross Amounts Carried At Close of Period
Land	20,487
Building and Land Improvements	77,203
Total	97,690
Accumulated Depreciation	(32,510)
7130 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,350
Building and Land Improvements	4,359
Costs Capitalized Subsequent to Acquisition	3,029
Gross Amounts Carried At Close of Period
Land	1,350
Building and Land Improvements	7,388
Total	8,738
Accumulated Depreciation	(4,363)
7134 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	704
Building and Land Improvements	4,700
Costs Capitalized Subsequent to Acquisition	817
Gross Amounts Carried At Close of Period
Land	704
Building and Land Improvements	5,517
Total	6,221
Accumulated Depreciation	(2,144)
7138 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,104
Building and Land Improvements	3,518
Costs Capitalized Subsequent to Acquisition	2,963
Gross Amounts Carried At Close of Period
Land	1,104
Building and Land Improvements	6,481
Total	7,585
Accumulated Depreciation	(4,506)
7142 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,342
Building and Land Improvements	7,148
Costs Capitalized Subsequent to Acquisition	2,851
Gross Amounts Carried At Close of Period
Land	1,342
Building and Land Improvements	9,999
Total	11,341
Accumulated Depreciation	(4,803)
7150 Columbia Gateway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,032
Building and Land Improvements	3,429
Costs Capitalized Subsequent to Acquisition	1,659
Gross Amounts Carried At Close of Period
Land	1,032
Building and Land Improvements	5,088
Total	6,120
Accumulated Depreciation	(2,165)
7150 Riverwood Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,821
Building and Land Improvements	4,388
Costs Capitalized Subsequent to Acquisition	3,436
Gross Amounts Carried At Close of Period
Land	1,821
Building and Land Improvements	7,824
Total	9,645
Accumulated Depreciation	(3,316)
7160 Riverwood Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,732
Building and Land Improvements	7,006
Costs Capitalized Subsequent to Acquisition	4,609
Gross Amounts Carried At Close of Period
Land	2,732
Building and Land Improvements	11,615
Total	14,347
Accumulated Depreciation	(5,835)
7170 Riverwood Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,283
Building and Land Improvements	3,096
Costs Capitalized Subsequent to Acquisition	2,387
Gross Amounts Carried At Close of Period
Land	1,283
Building and Land Improvements	5,483
Total	6,766
Accumulated Depreciation	(3,002)
7175 Riverwood Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,788
Building and Land Improvements	7,269
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,788
Building and Land Improvements	7,269
Total	9,057
Accumulated Depreciation	(1,661)
7200 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	8,348
Costs Capitalized Subsequent to Acquisition	81
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	8,429
Total	8,429
Accumulated Depreciation	(1,830)
7200 Riverwood Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	4,089
Building and Land Improvements	22,630
Costs Capitalized Subsequent to Acquisition	5,036
Gross Amounts Carried At Close of Period
Land	4,089
Building and Land Improvements	27,666
Total	31,755
Accumulated Depreciation	(14,245)
7205 Riverwood Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,367
Building and Land Improvements	21,419
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,367
Building and Land Improvements	21,419
Total	22,786
Accumulated Depreciation	(5,058)
7272 Park Circle Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,479
Building and Land Improvements	6,300
Costs Capitalized Subsequent to Acquisition	4,609
Gross Amounts Carried At Close of Period
Land	1,479
Building and Land Improvements	10,909
Total	12,388
Accumulated Depreciation	(6,471)
7318 Parkway Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	972
Building and Land Improvements	3,888
Costs Capitalized Subsequent to Acquisition	2,284
Gross Amounts Carried At Close of Period
Land	972
Building and Land Improvements	6,172
Total	7,144
Accumulated Depreciation	(3,374)
7400 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	9,223
Costs Capitalized Subsequent to Acquisition	75
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	9,298
Total	9,298
Accumulated Depreciation	(1,756)
7467 Ridge Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,565
Building and Land Improvements	3,116
Costs Capitalized Subsequent to Acquisition	6,876
Gross Amounts Carried At Close of Period
Land	1,565
Building and Land Improvements	9,992
Total	11,557
Accumulated Depreciation	(5,137)
7500 Advanced Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	18,665
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	18,665
Total	18,665
Accumulated Depreciation	(1,201)
7600 Advanced Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	13,752
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	13,752
Total	13,752
Accumulated Depreciation	(826)
7740 Milestone Parkway
Real Estate and Accumulated Depreciation
Encumbrances	15,942
Initial Cost
Land	3,825
Building and Land Improvements	34,176
Costs Capitalized Subsequent to Acquisition	1,262
Gross Amounts Carried At Close of Period
Land	3,825
Building and Land Improvements	35,438
Total	39,263
Accumulated Depreciation	(11,179)
7770 Backlick Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	6,387
Building and Land Improvements	78,892
Costs Capitalized Subsequent to Acquisition	1,669
Gross Amounts Carried At Close of Period
Land	6,387
Building and Land Improvements	80,561
Total	86,948
Accumulated Depreciation	(19,584)
7880 Milestone Parkway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	4,857
Building and Land Improvements	27,175
Costs Capitalized Subsequent to Acquisition	1,617
Gross Amounts Carried At Close of Period
Land	4,857
Building and Land Improvements	28,792
Total	33,649
Accumulated Depreciation	(5,068)
8000 Rideout Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	27,579
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	27,579
Total	27,579
Accumulated Depreciation	(529)
8100 Rideout Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	14,606
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	14,606
Total	14,606
Accumulated Depreciation	0
8200 Rideout Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	43,115
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	43,115
Total	43,115
Accumulated Depreciation	0
8300 Rideout Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	47,658
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	47,658
Total	47,658
Accumulated Depreciation	0
8600 Advanced Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	27,312
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	27,312
Total	27,312
Accumulated Depreciation	(1,394)
8621 Robert Fulton Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,317
Building and Land Improvements	12,642
Costs Capitalized Subsequent to Acquisition	7,680
Gross Amounts Carried At Close of Period
Land	2,317
Building and Land Improvements	20,322
Total	22,639
Accumulated Depreciation	(9,467)
8661 Robert Fulton Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,510
Building and Land Improvements	3,764
Costs Capitalized Subsequent to Acquisition	3,313
Gross Amounts Carried At Close of Period
Land	1,510
Building and Land Improvements	7,077
Total	8,587
Accumulated Depreciation	(4,129)
8671 Robert Fulton Drive
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,718
Building and Land Improvements	4,280
Costs Capitalized Subsequent to Acquisition	4,848
Gross Amounts Carried At Close of Period
Land	1,718
Building and Land Improvements	9,128
Total	10,846
Accumulated Depreciation	(5,418)
870 Elkridge Landing Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,003
Building and Land Improvements	9,442
Costs Capitalized Subsequent to Acquisition	10,464
Gross Amounts Carried At Close of Period
Land	2,003
Building and Land Improvements	19,906
Total	21,909
Accumulated Depreciation	(13,432)
8800 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	11,565
Initial Cost
Land	0
Building and Land Improvements	18,470
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	18,470
Total	18,470
Accumulated Depreciation	(1,437)
891 Elkridge Landing Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,165
Building and Land Improvements	4,772
Costs Capitalized Subsequent to Acquisition	3,994
Gross Amounts Carried At Close of Period
Land	1,165
Building and Land Improvements	8,766
Total	9,931
Accumulated Depreciation	(5,750)
901 Elkridge Landing Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,156
Building and Land Improvements	4,437
Costs Capitalized Subsequent to Acquisition	7,069
Gross Amounts Carried At Close of Period
Land	1,156
Building and Land Improvements	11,506
Total	12,662
Accumulated Depreciation	(5,724)
911 Elkridge Landing Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,215
Building and Land Improvements	4,861
Costs Capitalized Subsequent to Acquisition	3,347
Gross Amounts Carried At Close of Period
Land	1,215
Building and Land Improvements	8,208
Total	9,423
Accumulated Depreciation	(5,448)
938 Elkridge Landing Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	922
Building and Land Improvements	4,748
Costs Capitalized Subsequent to Acquisition	1,516
Gross Amounts Carried At Close of Period
Land	922
Building and Land Improvements	6,264
Total	7,186
Accumulated Depreciation	(3,619)
939 Elkridge Landing Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	939
Building and Land Improvements	3,756
Costs Capitalized Subsequent to Acquisition	4,687
Gross Amounts Carried At Close of Period
Land	939
Building and Land Improvements	8,443
Total	9,382
Accumulated Depreciation	(6,313)
Arundel Preserve
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	13,352
Building and Land Improvements	9,844
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	13,352
Building and Land Improvements	9,844
Total	23,196
Accumulated Depreciation	0
Canton Crossing Land
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	17,285
Building and Land Improvements	8,438
Costs Capitalized Subsequent to Acquisition	1,076
Gross Amounts Carried At Close of Period
Land	17,285
Building and Land Improvements	9,514
Total	26,799
Accumulated Depreciation	(17)
Canton Crossing Util Distr Ctr
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	6,100
Building and Land Improvements	10,450
Costs Capitalized Subsequent to Acquisition	1,974
Gross Amounts Carried At Close of Period
Land	6,100
Building and Land Improvements	12,424
Total	18,524
Accumulated Depreciation	(7,510)
Columbia Gateway - Southridge
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	6,387
Building and Land Improvements	3,725
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	6,387
Building and Land Improvements	3,725
Total	10,112
Accumulated Depreciation	0
Dahlgren Technology Center
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	978
Building and Land Improvements	178
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	978
Building and Land Improvements	178
Total	1,156
Accumulated Depreciation	0
Expedition VII
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	705
Building and Land Improvements	8,332
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	705
Building and Land Improvements	8,332
Total	9,037
Accumulated Depreciation	(113)
M Square Research Park
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	3,230
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	3,230
Total	3,230
Accumulated Depreciation	0
MR Land
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	9,038
Building and Land Improvements	809
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	9,038
Building and Land Improvements	809
Total	9,847
Accumulated Depreciation	0
National Business Park North
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	15,554
Building and Land Improvements	21,463
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	15,554
Building and Land Improvements	21,463
Total	37,017
Accumulated Depreciation	0
North Gate Business Park
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,755
Building and Land Improvements	5
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,755
Building and Land Improvements	5
Total	1,760
Accumulated Depreciation	0
NoVA Office A
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	2,096
Building and Land Improvements	46,849
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	2,096
Building and Land Improvements	46,849
Total	48,945
Accumulated Depreciation	(9,266)
NoVA Office B
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	739
Building and Land Improvements	38,376
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	739
Building and Land Improvements	38,376
Total	39,115
Accumulated Depreciation	(5,695)
NoVA Office C
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	7,751
Building and Land Improvements	80,771
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	7,751
Building and Land Improvements	80,771
Total	88,522
Accumulated Depreciation	(2,472)
NoVA Office D
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	6,587
Building and Land Improvements	40,559
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	6,587
Building and Land Improvements	40,559
Total	47,146
Accumulated Depreciation	(5,483)
Oak Grove A
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	12,866
Building and Land Improvements	41,488
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	12,866
Building and Land Improvements	41,488
Total	54,354
Accumulated Depreciation	(2,232)
Oak Grove B
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	12,866
Building and Land Improvements	41,443
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	12,866
Building and Land Improvements	41,443
Total	54,309
Accumulated Depreciation	(2,866)
Oak Grove C
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	11,741
Building and Land Improvements	77,526
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	11,741
Building and Land Improvements	77,526
Total	89,267
Accumulated Depreciation	(1,369)
Oak Grove D
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	11,741
Building and Land Improvements	71,279
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	11,741
Building and Land Improvements	71,279
Total	83,020
Accumulated Depreciation	(260)
Old Annapolis Road
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,637
Building and Land Improvements	5,500
Costs Capitalized Subsequent to Acquisition	6,902
Gross Amounts Carried At Close of Period
Land	1,637
Building and Land Improvements	12,402
Total	14,039
Accumulated Depreciation	(5,882)
P2 A
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	16,853
Building and Land Improvements	40,159
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	16,853
Building and Land Improvements	40,159
Total	57,012
Accumulated Depreciation	(2,576)
P2 B
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	22,839
Building and Land Improvements	36,388
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	22,839
Building and Land Improvements	36,388
Total	59,227
Accumulated Depreciation	(1,953)
P2 C
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	14,869
Building and Land Improvements	31,597
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	14,869
Building and Land Improvements	31,597
Total	46,466
Accumulated Depreciation	(1,485)
Patriot Ridge
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	18,517
Building and Land Improvements	14,599
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	18,517
Building and Land Improvements	14,599
Total	33,116
Accumulated Depreciation	0
Project EL
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	7,190
Building and Land Improvements	46,746
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	7,190
Building and Land Improvements	46,746
Total	53,936
Accumulated Depreciation	(1,705)
Project EX
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	13,010
Building and Land Improvements	19,107
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	13,010
Building and Land Improvements	19,107
Total	32,117
Accumulated Depreciation	(1,697)
PS A
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	4,078
Building and Land Improvements	8,808
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	4,078
Building and Land Improvements	8,808
Total	12,886
Accumulated Depreciation	0
PS B
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	3,468
Building and Land Improvements	4,407
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	3,468
Building and Land Improvements	4,407
Total	7,875
Accumulated Depreciation	0
Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	25,386
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	25,386
Total	25,386
Accumulated Depreciation	0
Sentry Gateway - T
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	14,020
Building and Land Improvements	38,804
Costs Capitalized Subsequent to Acquisition	13
Gross Amounts Carried At Close of Period
Land	14,020
Building and Land Improvements	38,817
Total	52,837
Accumulated Depreciation	(15,413)
Sentry Gateway - V
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	1,066
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	1,066
Total	1,066
Accumulated Depreciation	(374)
Sentry Gateway - W
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	1,884
Costs Capitalized Subsequent to Acquisition	71
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	1,955
Total	1,955
Accumulated Depreciation	(651)
Sentry Gateway - X
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,964
Building and Land Improvements	21,178
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,964
Building and Land Improvements	21,178
Total	23,142
Accumulated Depreciation	(6,434)
Sentry Gateway - Y
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,964
Building and Land Improvements	21,298
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,964
Building and Land Improvements	21,298
Total	23,262
Accumulated Depreciation	(6,472)
Sentry Gateway - Z
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	1,964
Building and Land Improvements	30,573
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	1,964
Building and Land Improvements	30,573
Total	32,537
Accumulated Depreciation	(5,968)
SP Manassas
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	8,156
Building and Land Improvements	921
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	8,156
Building and Land Improvements	921
Total	9,077
Accumulated Depreciation	0
Westfields - Park Center
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	8,667
Building and Land Improvements	3,170
Costs Capitalized Subsequent to Acquisition	0
Gross Amounts Carried At Close of Period
Land	8,667
Building and Land Improvements	3,170
Total	11,837
Accumulated Depreciation	0
Other Developments, including intercompany eliminations
Real Estate and Accumulated Depreciation
Encumbrances	0
Initial Cost
Land	0
Building and Land Improvements	1,169
Costs Capitalized Subsequent to Acquisition	258
Gross Amounts Carried At Close of Period
Land	0
Building and Land Improvements	1,427
Total	1,427
Accumulated Depreciation	$ (135)

Schedule III - Real Estate an_3

Schedule III - Real Estate and Accumulated Depreciation (Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes in cost of properties
Beginning balance	$ 4,959,709	$ 4,686,802	$ 4,348,006
Improvements and other additions	350,702	342,684	405,940
Sales	(323,874)	(103,097)	(65,475)
Impairments	0	0	(1,530)
Other dispositions	0	(4,511)	(139)
Reclassification from right-of-use asset	0	37,831	0
Ending balance	4,986,537	4,959,709	4,686,802
Changes in accumulated depreciation
Beginning balance	1,234,908	1,124,253	1,007,120
Depreciation expense	124,803	130,604	119,377
Sales	(86,263)	(15,438)	(2,105)
Other dispositions	0	(4,511)	(139)
Ending balance	$ 1,273,448	$ 1,234,908	$ 1,124,253

Uncategorized Items - ofc-20221

Label	Element	Value
Accounting Standards Update [Extensible Enumeration]	us-gaap_AccountingStandardsUpdateExtensibleList	Accounting Standards Update 2016-13 [Member]