COPT Defense Properties (CDP) 10-Q 4 Nov 24 2024 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2024	Oct. 21, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2024
Document Transition Report	false
Entity File Number	1-14023
Entity Registrant Name	COPT DEFENSE PROPERTIES
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	CDP
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		112,693,206
Entity Central Index Key	0000860546
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Properties, net:
Operating properties, net	$ 3,289,959	$ 3,246,806
Projects in development or held for future development	314,729	256,872
Total properties, net	3,604,688	3,503,678
Property - operating right-of-use assets	40,523	41,296
Cash and cash equivalents	34,478	167,820
Investment in unconsolidated real estate joint ventures	39,720	41,052
Accounts receivable, net	42,240	48,946
Deferred rent receivable	159,182	149,237
Lease incentives, net	63,034	61,331
Deferred leasing costs (net of accumulated amortization of $44,178 and $41,448, respectively)	71,815	70,057
Prepaid expenses and other assets, net	95,086	82,037
Total assets	4,234,302	4,246,966
Liabilities:
Debt, net	2,390,839	2,416,287
Accounts payable and accrued expenses	134,112	133,315
Rents received in advance and security deposits	33,213	35,409
Dividends and distributions payable	33,915	32,644
Deferred revenue associated with operating leases	37,660	29,049
Property - operating lease liabilities	33,615	33,931
Other liabilities	15,917	18,996
Total liabilities	2,679,271	2,699,631
Commitments and contingencies (Note 17)
Redeemable noncontrolling interests	22,436	23,580
Shareholders’ equity:
Common Shares of beneficial interest ($0.01 par value; 150,000,000 shares authorized; shares issued and outstanding of 112,693,206 at September 30, 2024 and 112,555,352 at December 31, 2023)	1,127	1,126
Additional paid-in capital	2,493,340	2,489,989
Cumulative distributions in excess of net income	(1,005,260)	(1,009,318)
Accumulated other comprehensive income	58	2,115
Total shareholders’ equity	1,489,265	1,483,912
Noncontrolling interests in subsidiaries:
Common units in COPT Defense Properties, L.P. (“CDPLP”)	28,918	25,502
Other consolidated entities	14,412	14,341
Noncontrolling interests in subsidiaries	43,330	39,843
Total equity	1,532,595	1,523,755
Total liabilities, redeemable noncontrolling interests and equity	4,234,302	4,246,966
Investing Receivables
Properties, net:
Investing receivables (net of allowance for credit losses of $2,867 and $2,377, respectively)	$ 83,536	$ 81,512

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Accumulated amortization of deferred leasing costs	$ 44,178	$ 41,448
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)	112,693,206	112,555,352
Common shares of beneficial interest, shares outstanding (in shares)	112,693,206	112,555,352
Investing Receivables
Investing receivable allowance for credit loss	$ 2,867	$ 2,377

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Revenues
Lease revenue	$ 170,549	$ 155,268	$ 501,601	$ 459,510
Other property revenue	2,014	1,339	4,710	3,731
Construction contract and other service revenues	16,662	11,949	63,523	42,012
Total revenues	189,225	168,556	569,834	505,253
Operating expenses
Property operating expenses	68,881	61,788	199,037	182,808
Depreciation and amortization associated with real estate operations	38,307	37,620	114,819	112,215
Construction contract and other service expenses	16,127	11,493	61,746	40,249
Impairment losses	0	252,797	0	252,797
General, administrative, leasing and other expenses	11,416	10,576	35,195	31,424
Total operating expenses	134,731	374,274	410,797	619,493
Interest expense	(20,376)	(17,798)	(61,760)	(50,759)
Interest and other income, net	3,324	2,529	10,330	6,928
Gain on sales of real estate	0	0	0	49,392
Income (loss) before equity in income (loss) of unconsolidated entities and income taxes	37,442	(220,987)	107,607	(108,679)
Equity in income (loss) of unconsolidated entities	85	(68)	180	(21)
Income tax expense	(130)	(152)	(312)	(467)
Net income (loss)	37,397	(221,207)	107,475	(109,167)
Net (income) loss attributable to noncontrolling interests:
Common units in CDPLP	(711)	3,691	(2,013)	1,882
Other consolidated entities	(601)	1,329	(1,654)	164
Net income (loss) attributable to common shareholders	$ 36,085	$ (216,187)	$ 103,808	$ (107,121)
Earnings per common share:
Net income (loss) attributable to common shareholders - basic (in dollars per share)	$ 0.32	$ (1.94)	$ 0.92	$ (0.96)
Net income (loss) attributable to common shareholders - diluted (in dollars per share)	$ 0.32	$ (1.94)	$ 0.92	$ (0.96)

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 37,397	$ (221,207)	$ 107,475	$ (109,167)
Other comprehensive (loss) income:
Unrealized (loss) income on interest rate derivatives	(2,582)	2,042	1,309	6,816
Reclassification adjustments on interest rate derivatives recognized in interest expense	(1,170)	(1,146)	(3,522)	(2,711)
Total other comprehensive (loss) income	(3,752)	896	(2,213)	4,105
Comprehensive income (loss)	33,645	(220,311)	105,262	(105,062)
Comprehensive (income) loss attributable to noncontrolling interests	(1,116)	4,994	(3,511)	1,964
Comprehensive income (loss) attributable to common shareholders	$ 32,529	$ (215,317)	$ 101,751	$ (103,098)

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Common Shares	Additional Paid-in Capital	Cumulative Distributions in Excess of Net Income	Accumulated Other Comprehensive Income	Noncontrolling Interests
Balance at Dec. 31, 2022	$ 1,721,455	$ 1,124	$ 2,486,116	$ (807,508)	$ 2,071	$ 39,652
Increase (Decrease) in Shareholders' Equity
Redemption of common units	(540)					(540)
Share-based compensation issued, net of redemptions	6,636	1	3,092			3,543
Redemption of vested equity awards	(1,199)		(1,199)
Adjustments to noncontrolling interests resulting from changes in ownership of CDPLP	0		22			(22)
Comprehensive (loss) income	(106,918)			(107,121)	4,023	(3,820)
Dividends	(96,256)			(96,256)
Distributions to owners of common units in CDPLP	(1,639)					(1,639)
Distributions to noncontrolling interests in other consolidated entities	(22)					(22)
Adjustments for changes in fair value of redeemable noncontrolling interests	1,686		1,686
Reclassification of redeemable noncontrolling interests to equity	2,670					2,670
Balance at Sep. 30, 2023	1,525,873	1,125	2,489,717	(1,010,885)	6,094	39,822
Balance at Jun. 30, 2023	1,776,695	1,125	2,486,996	(762,617)	5,224	45,967
Increase (Decrease) in Shareholders' Equity
Redemption of common units	(86)					(86)
Share-based compensation issued, net of redemptions	2,459		1,052			1,407
Redemption of vested equity awards	(48)		(48)
Adjustments to noncontrolling interests resulting from changes in ownership of CDPLP	0		1,324			(1,324)
Comprehensive (loss) income	(220,905)			(216,187)	870	(5,588)
Dividends	(32,081)			(32,081)
Distributions to owners of common units in CDPLP	(547)					(547)
Distributions to noncontrolling interests in other consolidated entities	(7)					(7)
Adjustments for changes in fair value of redeemable noncontrolling interests	393		393
Balance at Sep. 30, 2023	1,525,873	1,125	2,489,717	(1,010,885)	6,094	39,822
Balance at Dec. 31, 2023	1,523,755	1,126	2,489,989	(1,009,318)	2,115	39,843
Increase (Decrease) in Shareholders' Equity
Conversion of common units to common shares	0		538			(538)
Redemption of common units	(1,420)					(1,420)
Share-based compensation issued, net of redemptions	8,226	1	3,132			5,093
Redemption of vested equity awards	(1,194)		(1,194)
Adjustments to noncontrolling interests resulting from changes in ownership of CDPLP	0		(269)			269
Comprehensive (loss) income	103,816			103,808	(2,057)	2,065
Dividends	(99,750)			(99,750)
Distributions to owners of common units in CDPLP	(1,959)					(1,959)
Distributions to noncontrolling interests in other consolidated entities	(23)					(23)
Adjustments for changes in fair value of redeemable noncontrolling interests	1,144		1,144
Balance at Sep. 30, 2024	1,532,595	1,127	2,493,340	(1,005,260)	58	43,330
Balance at Jun. 30, 2024	1,530,506	1,127	2,489,931	(1,008,087)	3,614	43,921
Increase (Decrease) in Shareholders' Equity
Conversion of common units to common shares	0		538			(538)
Redemption of common units	(142)					(142)
Share-based compensation issued, net of redemptions	2,741		1,012			1,729
Redemption of vested equity awards	(66)		(66)
Adjustments to noncontrolling interests resulting from changes in ownership of CDPLP	0		1,597			(1,597)
Comprehensive (loss) income	33,139			36,085	(3,556)	610
Dividends	(33,258)			(33,258)
Distributions to owners of common units in CDPLP	(645)					(645)
Distributions to noncontrolling interests in other consolidated entities	(8)					(8)
Adjustments for changes in fair value of redeemable noncontrolling interests	328		328
Balance at Sep. 30, 2024	$ 1,532,595	$ 1,127	$ 2,493,340	$ (1,005,260)	$ 58	$ 43,330

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Stockholders' Equity [Abstract]
Beginning balance (in shares)	112,650,930	112,538,555	112,555,352	112,423,893
Conversion of common units to common shares (in shares)	40,000		40,000
Share-based compensation issued, net of redemptions (in shares)	2,276	9,291	97,854	123,953
Ending balance (in shares)	112,693,206	112,547,846	112,693,206	112,547,846

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash flows from operating activities
Revenues from real estate operations received	$ 513,267	$ 476,679
Construction contract and other service revenues received	60,441	59,245
Property operating expenses paid	(196,123)	(183,061)
Construction contract and other service expenses paid	(54,728)	(51,220)
General, administrative, leasing and other expenses paid	(26,210)	(24,739)
Interest expense paid	(58,742)	(42,829)
Lease incentives paid	(13,893)	(21,072)
Sales-type lease costs paid	(1,680)	(7,236)
Interest and other income received	6,426	3,021
Other	1,119	848
Net cash provided by operating activities	229,877	209,636
Cash flows from investing activities
Acquisitions of operating properties and related intangible assets	(32,244)	0
Properties in development or held for future development	(129,387)	(211,100)
Tenant improvements on operating properties	(36,698)	(57,020)
Other capital improvements on operating properties	(22,572)	(13,310)
Proceeds from sale of properties	0	189,506
Leasing costs paid	(10,743)	(10,698)
Other	2,524	775
Net cash used in investing activities	(229,120)	(101,847)
Proceeds from debt
Revolving Credit Facility	0	291,000
Unsecured senior notes	0	336,375
Repayments of debt
Revolving Credit Facility	0	(427,000)
Scheduled principal amortization	(1,879)	(2,289)
Other debt repayments	(27,649)	(15,902)
Common share dividends paid	(98,581)	(95,095)
Other	(6,401)	(6,055)
Net cash (used in) provided by financing activities	(134,510)	81,034
Net (decrease) increase in cash and cash equivalents and restricted cash	(133,753)	188,823
Cash and cash equivalents and restricted cash
Cash and cash equivalents and restricted cash at beginning of period	169,424	16,509
Cash and cash equivalents and restricted cash at end of period	35,671	205,332
Reconciliation of net income (loss) to net cash provided by operating activities:
Net income (loss)	107,475	(109,167)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and other amortization	116,605	114,041
Impairment losses	0	252,797
Amortization of deferred financing costs and net debt discounts	5,106	3,889
Change in net deferred rent receivable and liability	(1,103)	(2,899)
Gain on sales of real estate	0	(49,392)
Share-based compensation	7,826	6,226
Other	(2,399)	(2,382)
Changes in operating assets and liabilities:
Decrease in accounts receivable	6,503	3,111
Increase in lease incentives and prepaid expenses and other assets, net	(14,279)	(3,199)
Increase (decrease) in accounts payable, accrued expenses and other liabilities	6,339	(5,436)
(Decrease) increase in rents received in advance and security deposits	(2,196)	2,047
Net cash provided by operating activities	229,877	209,636
Reconciliation of cash and cash equivalents and restricted cash:
Cash and cash equivalents at beginning of period	167,820	12,337
Restricted cash at beginning of period	1,604	4,172
Cash and cash equivalents and restricted cash at beginning of period	169,424	16,509
Cash and cash equivalents at end of period	34,478	204,238
Restricted cash at end of period	1,193	1,094
Cash and cash equivalents and restricted cash at end of period	35,671	205,332
Supplemental schedule of non-cash investing and financing activities:
Decrease in accrued capital improvements, leasing and other investing activity costs	(9,008)	(18,931)
Recognition of operating right-of-use assets and related lease liabilities	2,976	6,714
Recognition of finance right-of-use assets and related lease liabilities	0	434
Investment in unconsolidated real estate joint venture retained in property disposition	0	21,121
(Decrease) increase in fair value of derivatives applied to accumulated other comprehensive income and noncontrolling interests	(2,213)	4,105
Dividends/distributions payable	33,915	32,645
Decrease in noncontrolling interests and increase in shareholders’ equity in connection with the conversion of common units into common shares	538	0
Adjustments to noncontrolling interests resulting from changes in CDPLP ownership	269	(22)
Decrease in redeemable noncontrolling interests and increase in equity to adjust for changes in fair value of redeemable noncontrolling interests	(1,144)	(1,686)
Reclassification of redeemable noncontrolling interests to equity	$ 0	$ 2,670

Organization

Organization	9 Months Ended
	Sep. 30, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization COPT Defense Properties (“COPT Defense”) and subsidiaries (collectively, the “Company”, “we” or “us”) is a fully-integrated and self-managed real estate investment trust (“REIT”) focused on owning, operating and developing properties in locations proximate to, or sometimes containing, key U.S. Government (“USG”) defense installations and missions (which we refer to herein as our Defense/IT Portfolio). Our tenants include the USG and their defense contractors, who are primarily engaged in priority national security activities, and who generally require mission-critical and high security property enhancements. As of September 30, 2024, our Defense/IT Portfolio included: > 194 operating properties totaling 22.2 million square feet comprised of 16.5 million square feet in 164 office properties and 5.7 million square feet in 30 single-tenant data center shells. We owned 24 of these data center shells through unconsolidated real estate joint ventures; > five properties under development (two office properties and three data center shells) that will total approximately 831,000 square feet upon completion; and > approximately 1,020 acres of land controlled that we believe could be developed into approximately 11.0 million square feet. We also owned eight other operating properties totaling 2.1 million square feet and approximately 50 acres of other developable land in the Greater Washington, DC/Baltimore region as of September 30, 2024. We conduct almost all of our operations and own almost all of our assets through our operating partnership, COPT Defense Properties, L.P. (“CDPLP”) and subsidiaries (collectively, the “Operating Partnership”), of which COPT Defense is the sole general partner. CDPLP owns real estate directly and through subsidiary partnerships and limited liability companies (“LLCs”). In addition to owning real estate, CDPLP 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 CDPLP are in the form of common and preferred units. As of September 30, 2024, COPT Defense owned 97.5% of the outstanding CDPLP common units (“common units”) and there were no preferred units outstanding. Common units not owned by COPT Defense carry certain redemption rights. The number of common units owned by COPT Defense is equivalent to the number of outstanding common shares of beneficial interest (“common shares”) of COPT Defense, and the entitlement of common units to quarterly distributions and payments in liquidation is substantially the same as that of COPT Defense common shareholders.

Summary of Significant Accounti

Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2024
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 Defense, the Operating Partnership, their subsidiaries and other entities in which COPT Defense 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. These interim financial statements should be read together with the consolidated financial statements and notes thereto as of and for the year ended December 31, 2023 included in our 2023 Annual Report on Form 10-K. The unaudited consolidated financial statements include all adjustments that are necessary, in the opinion of management, to fairly state our financial position and results of operations. All adjustments are of a normal recurring nature. The consolidated financial statements have been prepared using the accounting policies described in our 2023 Annual Report on Form 10-K. 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. Recent Accounting Pronouncements In November 2023, the Financial Accounting Standard Board (“FASB”) issued guidance to improve reportable segment disclosure requirements. This guidance requires disclosure of incremental segment information on an annual and interim basis and is effective for us beginning after December 15, 2024. Early adoption is permitted. The guidance will be applied retrospectively to all periods presented unless it is impracticable to do so. Upon application of this guidance, we expect to report certain additional segment disclosures, including information regarding our chief operating decision maker under the guidance and segment expenses, but otherwise do not expect it to affect our consolidated financial statements. In December 2023, the FASB issued guidance to improve income tax disclosures. This guidance requires enhanced annual disclosures primarily related to existing rate reconciliation and income taxes paid disclosure requirements and is effective for us for annual periods beginning after December 15, 2024. Early adoption is permitted. We expect to apply this guidance prospectively. We are currently assessing the application of this guidance but do not expect it to materially affect our future related disclosures. In March 2024, the FASB issued guidance to reduce complexity and diversity in practice in determining whether a profits interest award is accounted for as a share-based payment. This guidance is effective for us for annual and interim periods beginning after December 15, 2024. Early adoption is permitted. This guidance can be applied either retrospectively to all prior periods presented in the financial statements or prospectively to profits interest or similar awards granted or modified on or after the effective date for our application of this guidance. We do not expect the adoption of this guidance to affect our consolidated financial statements.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Recurring Fair Value Measurements The fair values of our interest rate derivatives, as disclosed in Note 9, 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 September 30, 2024, 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 7, 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 8, 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. The table below sets forth our financial assets and liabilities accounted for at fair value on a recurring basis as of September 30, 2024 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 Assets: (1) Interest rate derivatives $ — $ 754 $ — $ 754 Liabilities: (2) Interest rate derivatives $ — $ 409 $ — $ 409 (1) Included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheet. (2) Included in the line entitled “other liabilities” on our consolidated balance sheet.

Properties, Net

Properties, Net	9 Months Ended
	Sep. 30, 2024
Real Estate [Abstract]
Properties, Net	Properties, Net Operating properties, net consisted of the following (in thousands): September 30, December 31, Land $ 491,304 $ 482,964 Buildings and improvements 4,301,385 4,164,004 Less: Accumulated depreciation (1,502,730) (1,400,162) Operating properties, net $ 3,289,959 $ 3,246,806 In the nine months ended September 30, 2024, we acquired the following operating office properties: > 6841 Benjamin Franklin Drive, a 202,000 square foot property in Columbia, Maryland (included in the Fort Meade/BW Corridor sub-segment of our Defense/IT Portfolio reportable segment) that was 56% leased, for a purchase price of $15.0 million on March 15, 2024; and > 3900 Rogers Road, an 80,000 square foot property in San Antonio, Texas (included in the Lackland Air Force Base sub-segment of our Defense/IT Portfolio reportable segment) that was vacant on the acquisition date and subsequently leased in full, for a purchase price of $17.0 million on September 26, 2024. The table below sets forth the allocation of the aggregate purchase price and transaction costs associated with these acquisitions (in thousands): Land, operating properties $ 8,361 Building and improvements 16,635 Intangible assets on real estate acquisitions 7,248 Total acquisition cost $ 32,244 Intangible assets recorded in connection with these acquisitions included the following (dollars in thousands): Weighted Average Amortization Period Tenant relationship value $ 3,752 12.4 In-place lease value 2,229 2.4 Above-market leases 1,267 2.4 $ 7,248 7.6

Leases

Leases	9 Months Ended
	Sep. 30, 2024
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 Three Months Ended September 30, For the Nine Months Ended September 30, Lease revenue 2024 2023 2024 2023 Fixed $ 129,357 $ 120,408 $ 382,918 $ 354,908 Variable 41,192 34,860 118,683 104,602 $ 170,549 $ 155,268 $ 501,601 $ 459,510 Lessee Arrangements As of September 30, 2024, our balance sheet included $43.0 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating with various expiration dates. Our property right-of-use assets and property lease liabilities on our consolidated balance sheets consisted of the following (in thousands): Leases Balance Sheet Location September 30, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,523 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,510 2,565 Total right-of-use assets $ 43,033 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,615 $ 33,931 Finance leases - Property Other liabilities 397 415 Total lease liabilities $ 34,012 $ 34,346 As of September 30, 2024, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.36%, while our finance leases had a weighted average remaining lease term of eight years and a weighted average discount rate of 9.14%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease cost 2024 2023 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,929 $ 1,808 $ 5,687 $ 5,146 Property leases - variable Property operating expenses 42 17 219 50 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 18 56 57 Interest on lease liabilities Interest expense 9 10 28 33 $ 1,999 $ 1,853 $ 5,990 $ 5,286 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Nine Months Ended September 30, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 5,232 $ 4,432 Operating cash flows for financing leases $ 28 $ 33 Financing cash flows for financing leases $ 18 $ 14 Payments on property leases were due as follows (in thousands): September 30, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 1,746 $ 15 2025 2,589 63 2026 2,001 65 2027 2,016 67 2028 2,032 69 Thereafter 153,349 297 Total lease payments 163,733 576 Less: Amount representing interest (130,118) (179) Lease liability $ 33,615 $ 397 (1) Represents the three months ending December 31, 2024.
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 Three Months Ended September 30, For the Nine Months Ended September 30, Lease revenue 2024 2023 2024 2023 Fixed $ 129,357 $ 120,408 $ 382,918 $ 354,908 Variable 41,192 34,860 118,683 104,602 $ 170,549 $ 155,268 $ 501,601 $ 459,510 Lessee Arrangements As of September 30, 2024, our balance sheet included $43.0 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating with various expiration dates. Our property right-of-use assets and property lease liabilities on our consolidated balance sheets consisted of the following (in thousands): Leases Balance Sheet Location September 30, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,523 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,510 2,565 Total right-of-use assets $ 43,033 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,615 $ 33,931 Finance leases - Property Other liabilities 397 415 Total lease liabilities $ 34,012 $ 34,346 As of September 30, 2024, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.36%, while our finance leases had a weighted average remaining lease term of eight years and a weighted average discount rate of 9.14%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease cost 2024 2023 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,929 $ 1,808 $ 5,687 $ 5,146 Property leases - variable Property operating expenses 42 17 219 50 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 18 56 57 Interest on lease liabilities Interest expense 9 10 28 33 $ 1,999 $ 1,853 $ 5,990 $ 5,286 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Nine Months Ended September 30, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 5,232 $ 4,432 Operating cash flows for financing leases $ 28 $ 33 Financing cash flows for financing leases $ 18 $ 14 Payments on property leases were due as follows (in thousands): September 30, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 1,746 $ 15 2025 2,589 63 2026 2,001 65 2027 2,016 67 2028 2,032 69 Thereafter 153,349 297 Total lease payments 163,733 576 Less: Amount representing interest (130,118) (179) Lease liability $ 33,615 $ 397 (1) Represents the three months ending December 31, 2024.
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 Three Months Ended September 30, For the Nine Months Ended September 30, Lease revenue 2024 2023 2024 2023 Fixed $ 129,357 $ 120,408 $ 382,918 $ 354,908 Variable 41,192 34,860 118,683 104,602 $ 170,549 $ 155,268 $ 501,601 $ 459,510 Lessee Arrangements As of September 30, 2024, our balance sheet included $43.0 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating with various expiration dates. Our property right-of-use assets and property lease liabilities on our consolidated balance sheets consisted of the following (in thousands): Leases Balance Sheet Location September 30, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,523 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,510 2,565 Total right-of-use assets $ 43,033 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,615 $ 33,931 Finance leases - Property Other liabilities 397 415 Total lease liabilities $ 34,012 $ 34,346 As of September 30, 2024, our operating leases had a weighted average remaining lease term of 53 years and a weighted average discount rate of 7.36%, while our finance leases had a weighted average remaining lease term of eight years and a weighted average discount rate of 9.14%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease cost 2024 2023 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,929 $ 1,808 $ 5,687 $ 5,146 Property leases - variable Property operating expenses 42 17 219 50 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 18 56 57 Interest on lease liabilities Interest expense 9 10 28 33 $ 1,999 $ 1,853 $ 5,990 $ 5,286 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Nine Months Ended September 30, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 5,232 $ 4,432 Operating cash flows for financing leases $ 28 $ 33 Financing cash flows for financing leases $ 18 $ 14 Payments on property leases were due as follows (in thousands): September 30, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 1,746 $ 15 2025 2,589 63 2026 2,001 65 2027 2,016 67 2028 2,032 69 Thereafter 153,349 297 Total lease payments 163,733 576 Less: Amount representing interest (130,118) (179) Lease liability $ 33,615 $ 397 (1) Represents the three months ending December 31, 2024.

Real Estate Joint Ventures

Real Estate Joint Ventures	9 Months Ended
	Sep. 30, 2024
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 September 30, 2024 pertaining to our investments in consolidated real estate joint ventures, which are each variable interest entities (dollars in thousands): Nominal Ownership % September 30, 2024 Date Formed Total Encumbered Assets Total Liabilities Mortgage Debt Entity Location LW Redstone Company, LLC (1) 3/23/2010 85% Huntsville, Alabama $ 740,718 $ 35,023 $ 74,670 $ 22,227 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 130,342 — 2,599 — M Square Associates, LLC 6/26/2007 50% College Park, Maryland 97,273 56,446 49,272 47,741 $ 968,333 $ 91,469 $ 126,541 $ 69,968 (1) We fund all capital requirements. Our partner receives distributions of $1.2 million of annual operating cash flows and we receive the remainder. 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 Formed Nominal Ownership % Number of Properties Carrying Value of Investment (1) Entity September 30, December 31, Redshift JV LLC 1/10/2023 10% 3 $ 20,955 $ 21,053 BREIT COPT DC JV LLC 6/20/2019 10% 9 9,781 10,629 Quark JV LLC 12/14/2022 10% 2 6,711 6,727 B RE COPT DC JV III LLC 6/2/2021 10% 2 2,273 2,643 B RE COPT DC JV II LLC (2) 10/30/2020 10% 8 (3,370) (2,777) 24 $ 36,350 $ 38,275 (1) Included $39.7 million and $41.1 million reported in “investment in unconsolidated real estate joint ventures” and $3.4 million and $2.8 million for investments with deficit balances reported in “other liabilities” on our consolidated balance sheets as of September 30, 2024 and December 31, 2023, respectively. (2)

Investing Receivables

Investing Receivables	9 Months Ended
	Sep. 30, 2024
Receivables [Abstract]
Investing Receivables	Investing Receivables Investing receivables consisted of the following (in thousands): September 30, December 31, Notes receivable from the City of Huntsville $ 83,158 $ 77,022 Other investing loan receivable 3,245 6,867 Amortized cost basis 86,403 83,889 Allowance for credit losses (2,867) (2,377) Investing receivables, net $ 83,536 $ 81,512 The balances above include accrued interest receivable, net of allowance for credit losses, of $4.5 million as of September 30, 2024 and $6.0 million as of December 31, 2023. 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%. Our other investing loan receivable as of September 30, 2024 carries an effective interest rate of 14.0% and matures in 2025. The fair value of these receivables was approximately $86 million as of September 30, 2024 and $84 million as of December 31, 2023.

Debt, Net

Debt, Net	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Debt, Net	Debt, Net Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of September 30, 2024 September 30, December 31, Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed-rate mortgage debt $ 37,391 $ 66,314 3.82% June 2026 Variable-rate secured debt 32,577 32,894 SOFR + 0.10% + 1.45% to 1.55% (2) 2025-2026 (3) Total mortgage and other secured debt 69,968 99,208 Revolving Credit Facility 75,000 75,000 SOFR + 0.10% + 0.725% to 1.400% (4) October 2026 (5) Term Loan Facility 124,547 124,291 SOFR + 0.10% + 0.850% to 1.700% (6) January 2026 (7) Unsecured Senior Notes 2.25%, $400,000 aggregate principal 398,425 397,608 2.25% (8) March 2026 5.25%, $345,000 aggregate principal (9) 337,132 335,802 5.25% (10) September 2028 2.00%, $400,000 aggregate principal 397,838 397,471 2.00% (11) January 2029 2.75%, $600,000 aggregate principal 592,048 591,212 2.75% (12) April 2031 2.90%, $400,000 aggregate principal 395,584 395,265 2.90% (13) December 2033 Unsecured note payable 297 430 0% (14) May 2026 Total debt, net $ 2,390,839 $ 2,416,287 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $4.3 million as of September 30, 2024 and $5.3 million as of December 31, 2023. (2) Including the effect of interest rate swaps that hedge the risk of interest rate changes, the weighted average interest rate on our variable-rate secured debt as of September 30, 2024 was 2.44%; excluding the effect of these swaps, the weighted average interest rate on this debt as of September 30, 2024 was 6.87%. (3) Most of this debt matures in 2025, with the ability for us to extend such maturity by two 12-month periods at our option, provided that there is no default on the debt and we pay an extension fee of 0.10% of the debt balance for each extension period. (4) The weighted average interest rate on the Revolving Credit Facility was 6.35% as of September 30, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (5) The facility matures in October 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. (6) The interest rate on this loan was 6.60% as of September 30, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (7) This facility matures in January 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. (8) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.3 million as of September 30, 2024 and $1.9 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 2.48%. (9) As described further in our 2023 Annual Report on Form 10-K, these notes have an exchange settlement feature under which the notes may, under certain circumstances, be exchangeable at the option of the holders. Upon exchange, the principal amount of notes is payable in cash, with the remainder of the exchange obligation, if any, as determined based on the exchange price per common share at the time of settlement, payable in cash, common shares or a combination thereof at our election. As of September 30, 2024, the exchange rate of the notes equaled 33.3882 of our common shares per $1,000 principal amount of notes (equivalent to an exchange price of approximately $29.95 per common share). (10) The carrying value of these notes reflects unamortized commissions totaling $7.0 million as of September 30, 2024 and $8.1 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 5.83%. (11) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.5 million as of September 30, 2024 and $1.8 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 2.09%. (12) The carrying value of these notes reflects unamortized discounts and commissions totaling $6.9 million as of September 30, 2024 and $7.6 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 2.94%. (13) The carrying value of these notes reflects unamortized discounts and commissions totaling $3.6 million as of September 30, 2024 and $3.9 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 3.01%. (14) 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 $14,000 as of September 30, 2024 and $32,000 as of December 31, 2023. All debt is owed by the Operating Partnership. While COPT Defense is not directly obligated by any debt, it has guaranteed CDPLP’s Revolving Credit Facility, Term Loan Facility and Unsecured Senior Notes. All of our mortgage and other secured debt as of September 30, 2024 was for consolidated real estate joint ventures (see Note 6). The table below sets forth interest expense recognized on the 5.25% Exchangeable Senior Notes due 2028 (the “5.25% Notes”) for the three and nine months ended September 30, 2024 and 2023 (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Interest expense at stated interest rate $ 4,528 $ 956 $ 13,584 $ 956 Interest expense associated with amortization of debt discount and issuance costs 393 124 1,162 124 Total $ 4,921 $ 1,080 $ 14,746 $ 1,080 Certain of our debt instruments require that we comply with a number of restrictive financial covenants. As of September 30, 2024, we were compliant with these financial covenants. Our debt matures on the following schedule (in thousands): Year Ending December 31, September 30, 2024 2024 (1) $ 455 2025 23,717 2026 646,300 2027 — 2028 345,000 Thereafter 1,400,000 Total $ 2,415,472 (2) (1) Represents the three months ending December 31, 2024. (2) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $24.6 million. We capitalized interest costs of $712,000 in the three months ended September 30, 2024, $1.5 million in the three months ended September 30, 2023, $1.9 million in the nine months ended September 30, 2024 and $3.5 million in the nine months ended September 30, 2023. The following table sets forth information pertaining to the fair value of our debt (in thousands): September 30, 2024 December 31, 2023 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Fixed-rate debt Unsecured Senior Notes $ 2,121,027 $ 1,968,894 $ 2,117,358 $ 1,876,611 Other fixed-rate debt 37,688 35,959 66,744 63,692 Variable-rate debt 232,124 233,373 232,185 232,270 $ 2,390,839 $ 2,238,226 $ 2,416,287 $ 2,172,573

Interest Rate Derivatives

Interest Rate Derivatives	9 Months Ended
	Sep. 30, 2024
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): Fair Value at Notional Amount Fixed Rate Floating Rate Index Effective Date Expiration Date September 30, December 31, $ 10,460 (1) 1.678% SOFR + 0.10% 8/1/2019 8/1/2026 $ 343 $ 571 $ 22,250 (2) 0.573% SOFR + 0.10% 4/1/2020 3/26/2025 411 1,084 $ 150,000 3.742% One-Month SOFR 2/1/2023 2/2/2026 (304) 681 $ 50,000 3.747% One-Month SOFR 2/1/2023 2/2/2026 (105) 222 $ 345 $ 2,558 (1) The notional amount of this instrument is scheduled to amortize to $10.0 million. (2) The notional amount of this instrument is scheduled to amortize to $22.1 million. Each of these swaps was designated as a cash flow hedge of interest rate risk. 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 Derivatives Balance Sheet Location September 30, December 31, Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 754 $ 2,558 Interest rate swaps designated as cash flow hedges Other liabilities $ (409) $ — The table below presents the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of (Loss) Income Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations Derivatives in Hedging Relationships For the Three Months Ended September 30, For the Nine Months Ended September 30, For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 2024 2023 2024 2023 Interest rate derivatives $ (2,582) $ 2,042 $ 1,309 $ 6,816 $ 1,170 $ 1,146 $ 3,522 $ 2,711 Based on the fair value of our derivatives as of September 30, 2024, we estimate that approximately $708,000 of gains will be reclassified from accumulated other comprehensive income (“ AOCI”) as a decrease to interest expense over the next 12 months.

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests	9 Months Ended
	Sep. 30, 2024
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	Redeemable Noncontrolling Interests Redeemable noncontrolling interests on our consolidated balance sheets include the ownership interests of our partners in LW Redstone Company, LLC and Stevens Investors, LLC due to the partners’ rights to require us to acquire their interests. Effective in June 2023, these rights expired for our Stevens Investors, LLC partners, which resulted in our reclassification of their interests from redeemable noncontrolling interests to the noncontrolling interests in subsidiaries section of equity. The table below sets forth the activity for redeemable noncontrolling interests (in thousands): For the Nine Months Ended September 30, 2024 2023 Beginning balance $ 23,580 $ 26,293 Distributions to noncontrolling interests (1,446) (1,971) Net income attributable to noncontrolling interests 1,446 1,856 Adjustments for changes in fair value of interests (1,144) (1,686) Reclassification of Stevens Investors, LLC interests to equity — (2,670) Ending balance $ 22,436 $ 21,822

Equity

Equity	9 Months Ended
	Sep. 30, 2024
Equity [Abstract]
Equity	Equity As of September 30, 2024, we had remaining capacity under our at-the-market stock offering program equal to an aggregate gross sales price of $300 million in common shares. We declared dividends per common share of $0.295 in the three months ended September 30, 2024, $0.285 in the three months ended September 30, 2023, $0.885 in the nine months ended September 30, 2024 and $0.855 in the nine months ended September 30, 2023. During the nine months ended September 30, 2024, a CDPLP limited partner converted 40,000 common units in CDPLP for an equal number of common shares. See Note 15 for disclosure of common share activity pertaining to our share-based compensation plans.

Information by Business Segment

Information by Business Segment	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Information by Business Segment	Information by Business Segment We have the following reportable segments: Defense/IT Portfolio; and Other. We also report on Defense/IT Portfolio sub-segments, which include the following: Fort George G. Meade and the Baltimore/Washington Corridor (“Fort Meade/BW Corridor”); Northern Virginia Defense/IT Locations (“NoVA Defense/IT”); Lackland Air Force Base (in San Antonio, Texas); 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, Alabama); 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). 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 (“UJV” or “UJVs”) that is allocable to our ownership interest (“UJV NOI allocable to COPT Defense”). 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, net of deficit investment balances reported in “other liabilities” (which were included in our data center shells sub-segment and totaled $36.4 million and $39.2 million as of September 30, 2024 and 2023, respectively). In the third quarter of 2024, we retrospectively changed our segment assets definition to include deficit investment balances 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 Portfolio Fort Meade/BW Corridor NoVA Defense/IT Lackland Air Force Base Navy Support Redstone Arsenal Data Center Shells Total Defense/IT Portfolio Other Total Three Months Ended September 30, 2024 Revenues from real estate operations $ 80,056 $ 22,083 $ 16,879 $ 8,068 $ 18,332 $ 9,029 $ 154,447 $ 18,116 $ 172,563 Property operating expenses (27,929) (9,252) (9,160) (4,084) (6,463) (1,554) (58,442) (10,439) (68,881) UJV NOI allocable to COPT Defense — — — — — 1,844 1,844 — 1,844 NOI from real estate operations $ 52,127 $ 12,831 $ 7,719 $ 3,984 $ 11,869 $ 9,319 $ 97,849 $ 7,677 $ 105,526 Additions to long-lived assets $ 14,101 $ 5,357 $ 17,034 $ 3,520 $ 1,521 $ — $ 41,533 $ 4,040 $ 45,573 Transfers from non-operating properties $ 418 $ 16 $ — $ 66 $ 25,846 $ 406 $ 26,752 $ 141 $ 26,893 Three Months Ended September 30, 2023 Revenues from real estate operations $ 73,350 $ 20,333 $ 16,193 $ 8,190 $ 13,768 $ 6,811 $ 138,645 $ 17,962 $ 156,607 Property operating expenses (25,216) (7,900) (8,567) (3,933) (4,948) (678) (51,242) (10,546) (61,788) UJV NOI allocable to COPT Defense — — — — — 1,675 1,675 — 1,675 NOI from real estate operations $ 48,134 $ 12,433 $ 7,626 $ 4,257 $ 8,820 $ 7,808 $ 89,078 $ 7,416 $ 96,494 Additions to long-lived assets $ 7,057 $ 4,639 $ — $ 1,201 $ 8,566 $ — $ 21,463 $ 4,567 $ 26,030 Transfers from non-operating properties $ 983 $ 95 $ 51 $ 1 $ 63,025 $ 58,405 $ 122,560 $ 102 $ 122,662 Nine Months Ended September 30, 2024 Revenues from real estate operations $ 235,839 $ 64,110 $ 49,737 $ 24,534 $ 52,157 $ 27,086 $ 453,463 $ 52,848 $ 506,311 Property operating expenses (80,456) (27,444) (26,645) (11,343) (17,976) (4,588) (168,452) (30,585) (199,037) UJV NOI allocable to COPT Defense — — — — — 5,319 5,319 — 5,319 NOI from real estate operations $ 155,383 $ 36,666 $ 23,092 $ 13,191 $ 34,181 $ 27,817 $ 290,330 $ 22,263 $ 312,593 Additions to long-lived assets $ 48,161 $ 19,762 $ 17,034 $ 6,049 $ 2,545 $ — $ 93,551 $ 14,496 $ 108,047 Transfers from non-operating properties $ 2,658 $ 1,011 $ 9 $ 106 $ 60,119 $ 3,891 $ 67,794 $ 1,884 $ 69,678 Segment assets at September 30, 2024 $ 1,447,217 $ 492,912 $ 200,968 $ 161,007 $ 602,573 $ 427,972 $ 3,332,649 $ 314,806 $ 3,647,455 Nine Months Ended September 30, 2023 Revenues from real estate operations $ 215,303 $ 60,003 $ 49,393 $ 24,233 $ 40,160 $ 19,790 $ 408,882 $ 54,359 $ 463,241 Property operating expenses (73,924) (23,155) (26,463) (10,992) (14,334) (2,015) (150,883) (31,925) (182,808) UJV NOI allocable to COPT Defense — — — — — 4,988 4,988 — 4,988 NOI from real estate operations $ 141,379 $ 36,848 $ 22,930 $ 13,241 $ 25,826 $ 22,763 $ 262,987 $ 22,434 $ 285,421 Additions to long-lived assets $ 42,838 $ 14,994 $ 62 $ 2,269 $ 17,339 $ — $ 77,502 $ 12,572 $ 90,074 Transfers from non-operating properties $ 11,392 $ 582 $ 96 $ 2,651 $ 81,352 $ 63,653 $ 159,726 $ 129 $ 159,855 Segment assets at September 30, 2023 $ 1,397,107 $ 486,561 $ 190,344 $ 163,630 $ 548,201 $ 380,366 $ 3,166,209 $ 310,828 $ 3,477,037 The following table reconciles our segment revenues to total revenues as reported on our consolidated statements of operations (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Segment revenues from real estate operations $ 172,563 $ 156,607 $ 506,311 $ 463,241 Construction contract and other service revenues 16,662 11,949 63,523 42,012 Total revenues $ 189,225 $ 168,556 $ 569,834 $ 505,253 The following table reconciles UJV NOI allocable to COPT Defense to equity in income (loss) of unconsolidated entities as reported on our consolidated statements of operations (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 UJV NOI allocable to COPT Defense $ 1,844 $ 1,675 $ 5,319 $ 4,988 Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense (1,759) (1,743) (5,139) (5,006) Add: Equity in loss of unconsolidated non-real estate entities — — — (3) Equity in income (loss) of unconsolidated entities $ 85 $ (68) $ 180 $ (21) 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Construction contract and other service revenues $ 16,662 $ 11,949 $ 63,523 $ 42,012 Construction contract and other service expenses (16,127) (11,493) (61,746) (40,249) NOI from service operations $ 535 $ 456 $ 1,777 $ 1,763 The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to net income (loss) as reported on our consolidated statements of operations (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 NOI from real estate operations $ 105,526 $ 96,494 $ 312,593 $ 285,421 NOI from service operations 535 456 1,777 1,763 Depreciation and other amortization associated with real estate operations (38,307) (37,620) (114,819) (112,215) Impairment losses — (252,797) — (252,797) General, administrative, leasing and other expenses (11,416) (10,576) (35,195) (31,424) Interest expense (20,376) (17,798) (61,760) (50,759) Interest and other income, net 3,324 2,529 10,330 6,928 Gain on sales of real estate — — — 49,392 Equity in income (loss) of unconsolidated entities 85 (68) 180 (21) UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities (1,844) (1,675) (5,319) (4,988) Income tax expense (130) (152) (312) (467) Net income (loss) $ 37,397 $ (221,207) $ 107,475 $ (109,167) The following table reconciles our segment assets to our consolidated total assets (in thousands): September 30, September 30, Segment assets $ 3,647,455 $ 3,477,037 Operating properties lease liabilities included in segment assets 34,012 33,360 Investment in UJV deficit balance included in segment assets 3,370 2,327 Non-operating property assets 314,729 324,168 Other assets 234,736 402,365 Total consolidated assets $ 4,234,302 $ 4,239,257 The accounting policies of the segments are the same as those used to prepare our consolidated financial statements. In the segment reporting presented above, we did not allocate interest expense, depreciation and amortization, impairment losses, gain on sales of real estate and equity in income (loss) 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, leasing and other expenses, interest and other income, net, 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	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Construction Contract and Other Service Revenues	Construction Contract and Other Service Revenues We disaggregate in the table below our construction contract and other service revenues by compensation arrangement as we believe it best depicts the nature, timing and uncertainty of our revenue (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Construction contract revenue: Firm fixed price $ 8,158 $ 6,616 $ 29,343 $ 21,898 Guaranteed maximum price 6,318 2,817 28,410 11,561 Cost-plus fee 1,868 2,205 4,574 7,472 Other 318 311 1,196 1,081 $ 16,662 $ 11,949 $ 63,523 $ 42,012 We recognized an insignificant amount of revenue in the three and nine months ended September 30, 2024 and 2023 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 Nine Months Ended September 30, 2024 2023 Beginning balance $ 10,500 $ 7,618 Ending balance $ 3,836 $ 5,367 Contract assets 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 Nine Months Ended September 30, 2024 2023 Beginning balance $ 15,086 $ 22,331 Ending balance $ 22,540 $ 8,356 Contract liabilities are included in other liabilities on our consolidated balance sheets. Changes in contract liabilities were as follows (in thousands): For the Nine Months Ended September 30, 2024 2023 Beginning balance $ 4,176 $ 2,867 Ending balance $ 2,536 $ 3,938 Portion of beginning balance recognized in revenue during: Three months ended September 30, $ 87 $ 64 Nine months ended September 30, $ 2,198 $ 164 Revenue allocated to the remaining performance obligations under existing contracts as of September 30, 2024 that will be recognized as revenue in future periods was $22.7 million, most of which we expect to recognize in the three months ending December 31, 2024.

Credit Losses on Financial Asse

Credit Losses on Financial Assets and Other Instruments	9 Months Ended
	Sep. 30, 2024
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 for the nine months ended September 30, 2024 and 2023 (in thousands): Investing Receivables Tenant Notes Other Assets (2) Total December 31, 2023 $ 2,377 $ 666 $ 153 $ 3,196 Net credit loss expense (recoveries) (3) 490 57 (51) 496 September 30, 2024 $ 2,867 $ 723 $ 102 $ 3,692 December 31, 2022 $ 2,794 $ 778 $ 268 $ 3,840 Net credit loss expense (recoveries) (3) 829 (64) (88) 677 Write-offs — (33) — (33) September 30, 2023 $ 3,623 $ 681 $ 180 $ 4,484 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of September 30, 2024 and December 31, 2023 included $46,000 and $87,000, respectively, in the line entitled “accounts receivable, net” and $56,000 and $66,000, respectively, in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. (3) Included in the line entitled “interest and other income, net” on our consolidated statements of operations. 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 September 30, 2024 (in thousands): Origination Year 2019 and Earlier 2020 2021 2022 2023 2024 Total Investing receivables: Credit risk classification: Investment grade $ 69,247 $ 2,656 $ 10,623 $ — $ 632 $ — $ 83,158 Non-investment grade — — — 3,245 — — 3,245 Total $ 69,247 $ 2,656 $ 10,623 $ 3,245 $ 632 $ — $ 86,403 Tenant notes receivable: Credit risk classification: Investment grade $ 591 $ 51 $ — $ — $ — $ — $ 642 Non-investment grade 110 1,333 — — — 446 1,889 Total $ 701 $ 1,384 $ — $ — $ — $ 446 $ 2,531 Sales-type lease receivables: Credit risk classification: Investment grade $ — $ 4,644 $ — $ — $ — $ 965 $ 5,609 Our investment grade credit risk classification represents entities with investment grade credit ratings from ratings agencies (such as S&P Global Ratings, Moody’s Investors Service, Inc. or Fitch Ratings, Inc.), 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 September 2024. An insignificant portion of the tenant notes receivable set forth above was past due, which we define as being delinquent by more than three months from the due date.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation Restricted Shares The following table summarizes restricted shares activity under our share-based compensation plans for the nine months ended September 30, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 353,455 $ 25.82 Granted 167,502 $ 24.84 Forfeited (20,980) $ 25.77 Vested (152,642) $ 25.82 Unvested as of September 30, 2024 347,335 $ 25.35 Restricted shares granted to employees generally 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 $3.7 million for the nine months ended September 30, 2024. Profit Interest Units in CDPLP (“PIUs”) We granted two forms of PIUs: time-based PIUs (“TB-PIUs”); and performance-based PIUs (“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 automatically convert into common units in CDPLP if, or when, a book-up event (as defined under federal income tax regulations) has occurred and carry substantially the same rights to distributions as common units. TB-PIUs The following table summarizes TB-PIUs activity under our share-based compensation plans for the nine months ended September 30, 2024: Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 194,415 $ 25.76 Granted 127,795 $ 24.57 Vested (93,577) $ 25.63 Unvested as of September 30, 2024 228,633 $ 25.15 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 common units but carry no redemption rights. The aggregate intrinsic value of TB-PIUs that vested was $2.3 million for the nine months ended September 30, 2024. PB-PIUs On January 1, 2024, we granted certain senior management team members 299,766 PB-PIUs with a three-year performance period concluding on the earlier of December 31, 2026 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 following the end of the performance period will be determined based on the percentile rank of COPT Defense’s total shareholder return (“TSR”) relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned PB-PIUs 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 is negative when its TSR’s percentile rank exceeds the 50th percentile, then the earned PB-PIU payout percentage used to arrive at the earned awards would be reduced by 12.5 percentage points, but in no event to a payout percentage of less than 50% of PB-PIUs granted; however, the resulting reduction in earned awards would subsequently be deemed earned awards if COPT Defense’s TSR becomes positive on any date in the calendar year following the end of the performance period. In addition, regardless of COPT Defense’s TSR relative to the peer group, no less than 50% (target) of the PB-PIUs granted will be earned if COPT Defense’s TSR is at least 10% and no less than 25% of the PB-PIUs granted will be earned if COPT Defense’s TSR is at least 6%, with linear interpolation if COPT Defense’s TSR is between 6% and 10%. During the performance period, PB-PIUs carry rights to distributions equal to 10% of the distribution rights of common units but carry no redemption rights. Following the end of the performance period, we will settle the award by issuing vested PIUs equal to: the number of earned awards; and 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 through the date of settlement, divided by the price of our common shares over a defined period of time. 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. These PB-PIU grants had an aggregate grant date fair value of $5.4 million ($36.06 per target-level award associated with the grants) that is being recognized over the performance period. The grant date fair value was computed using a Monte Carlo model that included the following assumptions: baseline common share value of $25.63; expected volatility for common shares of 25.9%; and a risk-free interest rate of 4.13%. Based on COPT Defense’s TSR relative to its peer group of companies, for the 2021 PB-PIUs issued to executives that vested on December 31, 2023, we issued 211,845 PIUs in settlement of the PB-PIUs on February 1, 2024. Deferred Share Awards During the nine months ended September 30, 2024, non-employee Trustees were granted 8,796 deferred share awards with an aggregate grant date fair value of $217,000 ($24.66 per award). 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).

Earnings Per Share ("EPS")

Earnings Per Share ("EPS")	9 Months Ended
	Sep. 30, 2024
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 (loss) available to common shareholders allocable to unrestricted common shares by the weighted average number of unrestricted common shares outstanding during the period after allocating undistributed earnings between common shareholders and participating securities under the two-class method. Our participating securities include restricted shares and PIUs and deferred share awards not previously settled by common share issuances. 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. We compute diluted EPS using the treasury stock method for unvested restricted shares, TB-PIUs and deferred share awards and the if-converted method for common units, redeemable noncontrolling interests, PB-PIUs and vested PIUs and deferred share awards not previously settled by common share issuances. 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net income (loss) attributable to common shareholders $ 36,085 $ (216,187) $ 103,808 $ (107,121) Income attributable to share-based compensation awards for basic EPS (127) (992) (385) (1,093) Numerator for basic EPS on net income (loss) attributable to common shareholders 35,958 (217,179) 103,423 (108,214) Adjustment to income attributable to share-based compensation awards for diluted EPS 23 — 66 — Numerator for diluted EPS on net income (loss) attributable to common shareholders $ 35,981 $ (217,179) $ 103,489 $ (108,214) Denominator (all weighted averages): Denominator for basic EPS (common shares) 112,314 112,196 112,279 112,170 Dilutive effect of share-based compensation awards 696 — 566 — Denominator for diluted EPS (common shares) 113,010 112,196 112,845 112,170 Basic EPS attributable to common shareholders $ 0.32 $ (1.94) $ 0.92 $ (0.96) Diluted EPS attributable to common shareholders $ 0.32 $ (1.94) $ 0.92 $ (0.96) 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Conversion of common units 1,696 1,520 1,675 1,508 Conversion of redeemable noncontrolling interests 747 882 873 980 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 for the three months ended September 30, 2024 and 2023 of 436,000 and 423,000, respectively, and for the nine months ended September 30, 2024 and 2023 of 433,000 and 411,000, respectively; > weighted average TB-PIUs for the three months ended September 30, 2024 and 2023 of 229,000 and 171,000, respectively, and for the nine months ended September 30, 2024 and 2023 of 221,000 and 174,000, respectively; > weighted average vested PIUs for the three months ended September 30, 2024 and 2023 of 223,000 and 170,000, respectively, and for the nine months ended September 30, 2024 and 2023 of 212,000 and 148,000, respectively; and > weighted average PB-PIUs for the three months ended September 30, 2024 and 2023 of 718,000 and 608,000, respectively, and for the nine months ended September 30, 2024 and 2023 of 740,000 and 636,000, respectively. Our 5.25% Notes have an exchange settlement feature under which the principal amount of notes exchanged is payable in cash, with the remainder of the exchange obligation, if any, as determined based on the exchange price per common share at the time of settlement, payable in cash, common shares or a combination thereof at our election. These notes did not affect our diluted EPS reported above since the weighted average closing price of our common shares for the three and nine months ended September 30, 2024 and 2023 was less than the exchange price applicable to that period.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2024
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 September 30, 2024, management believes that it is reasonably possible that we could recognize a loss of up to $4.8 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 $25 million as of September 30, 2024. 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 September 30, 2024, we do not expect any such future fundings will be required.

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Sep. 30, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2024
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These consolidated financial statements include the accounts of COPT Defense, the Operating Partnership, their subsidiaries and other entities in which COPT Defense 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. These interim financial statements should be read together with the consolidated financial statements and notes thereto as of and for the year ended December 31, 2023 included in our 2023 Annual Report on Form 10-K. The unaudited consolidated financial statements include all adjustments that are necessary, in the opinion of management, to fairly state our financial position and results of operations. All adjustments are of a normal recurring nature. The consolidated financial statements have been prepared using the accounting policies described in our 2023 Annual Report on Form 10-K.
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.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In November 2023, the Financial Accounting Standard Board (“FASB”) issued guidance to improve reportable segment disclosure requirements. This guidance requires disclosure of incremental segment information on an annual and interim basis and is effective for us beginning after December 15, 2024. Early adoption is permitted. The guidance will be applied retrospectively to all periods presented unless it is impracticable to do so. Upon application of this guidance, we expect to report certain additional segment disclosures, including information regarding our chief operating decision maker under the guidance and segment expenses, but otherwise do not expect it to affect our consolidated financial statements. In December 2023, the FASB issued guidance to improve income tax disclosures. This guidance requires enhanced annual disclosures primarily related to existing rate reconciliation and income taxes paid disclosure requirements and is effective for us for annual periods beginning after December 15, 2024. Early adoption is permitted. We expect to apply this guidance prospectively. We are currently assessing the application of this guidance but do not expect it to materially affect our future related disclosures. In March 2024, the FASB issued guidance to reduce complexity and diversity in practice in determining whether a profits interest award is accounted for as a share-based payment. This guidance is effective for us for annual and interim periods beginning after December 15, 2024. Early adoption is permitted. This guidance can be applied either retrospectively to all prior periods presented in the financial statements or prospectively to profits interest or similar awards granted or modified on or after the effective date for our application of this guidance. We do not expect the adoption of this guidance to affect our consolidated financial statements.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2024
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 September 30, 2024 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 Assets: (1) Interest rate derivatives $ — $ 754 $ — $ 754 Liabilities: (2) Interest rate derivatives $ — $ 409 $ — $ 409 (1) Included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheet. (2) Included in the line entitled “other liabilities” on our consolidated balance sheet.

Properties, Net (Tables)

Properties, Net (Tables)	9 Months Ended
	Sep. 30, 2024
Real Estate [Abstract]
Schedule of Operating Properties, Net	Operating properties, net consisted of the following (in thousands): September 30, December 31, Land $ 491,304 $ 482,964 Buildings and improvements 4,301,385 4,164,004 Less: Accumulated depreciation (1,502,730) (1,400,162) Operating properties, net $ 3,289,959 $ 3,246,806
Schedule of Allocation of Acquisition Costs	The table below sets forth the allocation of the aggregate purchase price and transaction costs associated with these acquisitions (in thousands): Land, operating properties $ 8,361 Building and improvements 16,635 Intangible assets on real estate acquisitions 7,248 Total acquisition cost $ 32,244
Schedule of Intangible Assets Acquired	Intangible assets recorded in connection with these acquisitions included the following (dollars in thousands): Weighted Average Amortization Period Tenant relationship value $ 3,752 12.4 In-place lease value 2,229 2.4 Above-market leases 1,267 2.4 $ 7,248 7.6

Leases (Tables)

Leases (Tables)	9 Months Ended
	Sep. 30, 2024
Leases [Abstract]
Schedule of Lease Revenue Recognized Between Fixed and Variable Lease Revenue	The table below sets forth our composition of lease revenue recognized between fixed- and variable-lease revenue (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease revenue 2024 2023 2024 2023 Fixed $ 129,357 $ 120,408 $ 382,918 $ 354,908 Variable 41,192 34,860 118,683 104,602 $ 170,549 $ 155,268 $ 501,601 $ 459,510
Schedule of Property Right-of-use Assets and Lease Liabilities	Our property right-of-use assets and property lease liabilities on our consolidated balance sheets consisted of the following (in thousands): Leases Balance Sheet Location September 30, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,523 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,510 2,565 Total right-of-use assets $ 43,033 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,615 $ 33,931 Finance leases - Property Other liabilities 397 415 Total lease liabilities $ 34,012 $ 34,346
Schedule of Property Lease Costs and Effect of Property Lease Payments on Consolidated Statements of Cash Flows	The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Three Months Ended September 30, For the Nine Months Ended September 30, Lease cost 2024 2023 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,929 $ 1,808 $ 5,687 $ 5,146 Property leases - variable Property operating expenses 42 17 219 50 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 18 56 57 Interest on lease liabilities Interest expense 9 10 28 33 $ 1,999 $ 1,853 $ 5,990 $ 5,286 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Nine Months Ended September 30, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 5,232 $ 4,432 Operating cash flows for financing leases $ 28 $ 33 Financing cash flows for financing leases $ 18 $ 14
Schedule of Payments Due on Property Operating Leases	Payments on property leases were due as follows (in thousands): September 30, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 1,746 $ 15 2025 2,589 63 2026 2,001 65 2027 2,016 67 2028 2,032 69 Thereafter 153,349 297 Total lease payments 163,733 576 Less: Amount representing interest (130,118) (179) Lease liability $ 33,615 $ 397 (1) Represents the three months ending December 31, 2024.
Schedule of Payments Due on Property Finance Leases	Payments on property leases were due as follows (in thousands): September 30, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 1,746 $ 15 2025 2,589 63 2026 2,001 65 2027 2,016 67 2028 2,032 69 Thereafter 153,349 297 Total lease payments 163,733 576 Less: Amount representing interest (130,118) (179) Lease liability $ 33,615 $ 397 (1) Represents the three months ending December 31, 2024.

Real Estate Joint Ventures (Tab

Real Estate Joint Ventures (Tables)	9 Months Ended
	Sep. 30, 2024
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 September 30, 2024 pertaining to our investments in consolidated real estate joint ventures, which are each variable interest entities (dollars in thousands): Nominal Ownership % September 30, 2024 Date Formed Total Encumbered Assets Total Liabilities Mortgage Debt Entity Location LW Redstone Company, LLC (1) 3/23/2010 85% Huntsville, Alabama $ 740,718 $ 35,023 $ 74,670 $ 22,227 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 130,342 — 2,599 — M Square Associates, LLC 6/26/2007 50% College Park, Maryland 97,273 56,446 49,272 47,741 $ 968,333 $ 91,469 $ 126,541 $ 69,968 (1) We fund all capital requirements. Our partner receives distributions of $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 Formed Nominal Ownership % Number of Properties Carrying Value of Investment (1) Entity September 30, December 31, Redshift JV LLC 1/10/2023 10% 3 $ 20,955 $ 21,053 BREIT COPT DC JV LLC 6/20/2019 10% 9 9,781 10,629 Quark JV LLC 12/14/2022 10% 2 6,711 6,727 B RE COPT DC JV III LLC 6/2/2021 10% 2 2,273 2,643 B RE COPT DC JV II LLC (2) 10/30/2020 10% 8 (3,370) (2,777) 24 $ 36,350 $ 38,275 (1) Included $39.7 million and $41.1 million reported in “investment in unconsolidated real estate joint ventures” and $3.4 million and $2.8 million for investments with deficit balances reported in “other liabilities” on our consolidated balance sheets as of September 30, 2024 and December 31, 2023, respectively. (2)

Investing Receivables (Tables)

Investing Receivables (Tables)	9 Months Ended
	Sep. 30, 2024
Receivables [Abstract]
Schedule of Investing Receivables	Investing receivables consisted of the following (in thousands): September 30, December 31, Notes receivable from the City of Huntsville $ 83,158 $ 77,022 Other investing loan receivable 3,245 6,867 Amortized cost basis 86,403 83,889 Allowance for credit losses (2,867) (2,377) Investing receivables, net $ 83,536 $ 81,512

Debt, Net (Tables)

Debt, Net (Tables)	9 Months Ended
	Sep. 30, 2024
Debt Disclosure [Abstract]
Schedule of Debt	Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of September 30, 2024 September 30, December 31, Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed-rate mortgage debt $ 37,391 $ 66,314 3.82% June 2026 Variable-rate secured debt 32,577 32,894 SOFR + 0.10% + 1.45% to 1.55% (2) 2025-2026 (3) Total mortgage and other secured debt 69,968 99,208 Revolving Credit Facility 75,000 75,000 SOFR + 0.10% + 0.725% to 1.400% (4) October 2026 (5) Term Loan Facility 124,547 124,291 SOFR + 0.10% + 0.850% to 1.700% (6) January 2026 (7) Unsecured Senior Notes 2.25%, $400,000 aggregate principal 398,425 397,608 2.25% (8) March 2026 5.25%, $345,000 aggregate principal (9) 337,132 335,802 5.25% (10) September 2028 2.00%, $400,000 aggregate principal 397,838 397,471 2.00% (11) January 2029 2.75%, $600,000 aggregate principal 592,048 591,212 2.75% (12) April 2031 2.90%, $400,000 aggregate principal 395,584 395,265 2.90% (13) December 2033 Unsecured note payable 297 430 0% (14) May 2026 Total debt, net $ 2,390,839 $ 2,416,287 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $4.3 million as of September 30, 2024 and $5.3 million as of December 31, 2023. (2) Including the effect of interest rate swaps that hedge the risk of interest rate changes, the weighted average interest rate on our variable-rate secured debt as of September 30, 2024 was 2.44%; excluding the effect of these swaps, the weighted average interest rate on this debt as of September 30, 2024 was 6.87%. (3) Most of this debt matures in 2025, with the ability for us to extend such maturity by two 12-month periods at our option, provided that there is no default on the debt and we pay an extension fee of 0.10% of the debt balance for each extension period. (4) The weighted average interest rate on the Revolving Credit Facility was 6.35% as of September 30, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (5) The facility matures in October 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. (6) The interest rate on this loan was 6.60% as of September 30, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (7) This facility matures in January 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. (8) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.3 million as of September 30, 2024 and $1.9 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 2.48%. (9) As described further in our 2023 Annual Report on Form 10-K, these notes have an exchange settlement feature under which the notes may, under certain circumstances, be exchangeable at the option of the holders. Upon exchange, the principal amount of notes is payable in cash, with the remainder of the exchange obligation, if any, as determined based on the exchange price per common share at the time of settlement, payable in cash, common shares or a combination thereof at our election. As of September 30, 2024, the exchange rate of the notes equaled 33.3882 of our common shares per $1,000 principal amount of notes (equivalent to an exchange price of approximately $29.95 per common share). (10) The carrying value of these notes reflects unamortized commissions totaling $7.0 million as of September 30, 2024 and $8.1 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 5.83%. (11) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.5 million as of September 30, 2024 and $1.8 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 2.09%. (12) The carrying value of these notes reflects unamortized discounts and commissions totaling $6.9 million as of September 30, 2024 and $7.6 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 2.94%. (13) The carrying value of these notes reflects unamortized discounts and commissions totaling $3.6 million as of September 30, 2024 and $3.9 million as of December 31, 2023. The effective interest rate under the notes, including amortization of such costs, was 3.01%. (14) 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 $14,000 as of September 30, 2024 and $32,000 as of December 31, 2023.
Schedule of Interest Expense	The table below sets forth interest expense recognized on the 5.25% Exchangeable Senior Notes due 2028 (the “5.25% Notes”) for the three and nine months ended September 30, 2024 and 2023 (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Interest expense at stated interest rate $ 4,528 $ 956 $ 13,584 $ 956 Interest expense associated with amortization of debt discount and issuance costs 393 124 1,162 124 Total $ 4,921 $ 1,080 $ 14,746 $ 1,080
Schedule of Debt Maturities	Our debt matures on the following schedule (in thousands): Year Ending December 31, September 30, 2024 2024 (1) $ 455 2025 23,717 2026 646,300 2027 — 2028 345,000 Thereafter 1,400,000 Total $ 2,415,472 (2) (1) Represents the three months ending December 31, 2024. (2) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $24.6 million.
Schedule of Fair Value of Debt	The following table sets forth information pertaining to the fair value of our debt (in thousands): September 30, 2024 December 31, 2023 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Fixed-rate debt Unsecured Senior Notes $ 2,121,027 $ 1,968,894 $ 2,117,358 $ 1,876,611 Other fixed-rate debt 37,688 35,959 66,744 63,692 Variable-rate debt 232,124 233,373 232,185 232,270 $ 2,390,839 $ 2,238,226 $ 2,416,287 $ 2,172,573

Interest Rate Derivatives (Tabl

Interest Rate Derivatives (Tables)	9 Months Ended
	Sep. 30, 2024
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): Fair Value at Notional Amount Fixed Rate Floating Rate Index Effective Date Expiration Date September 30, December 31, $ 10,460 (1) 1.678% SOFR + 0.10% 8/1/2019 8/1/2026 $ 343 $ 571 $ 22,250 (2) 0.573% SOFR + 0.10% 4/1/2020 3/26/2025 411 1,084 $ 150,000 3.742% One-Month SOFR 2/1/2023 2/2/2026 (304) 681 $ 50,000 3.747% One-Month SOFR 2/1/2023 2/2/2026 (105) 222 $ 345 $ 2,558 (1) The notional amount of this instrument is scheduled to amortize to $10.0 million. (2) The notional amount of this instrument is scheduled to amortize to $22.1 million.
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 Derivatives Balance Sheet Location September 30, December 31, Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 754 $ 2,558 Interest rate swaps designated as cash flow hedges Other liabilities $ (409) $ —
Schedule of Effect of Interest Rate Derivatives on Consolidated Statements of Operations and Comprehensive Income	The table below presents the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of (Loss) Income Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations Derivatives in Hedging Relationships For the Three Months Ended September 30, For the Nine Months Ended September 30, For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 2024 2023 2024 2023 Interest rate derivatives $ (2,582) $ 2,042 $ 1,309 $ 6,816 $ 1,170 $ 1,146 $ 3,522 $ 2,711

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Tables)	9 Months Ended
	Sep. 30, 2024
Noncontrolling Interest [Abstract]
Schedule of Activity for Redeemable Noncontrolling Interest	The table below sets forth the activity for redeemable noncontrolling interests (in thousands): For the Nine Months Ended September 30, 2024 2023 Beginning balance $ 23,580 $ 26,293 Distributions to noncontrolling interests (1,446) (1,971) Net income attributable to noncontrolling interests 1,446 1,856 Adjustments for changes in fair value of interests (1,144) (1,686) Reclassification of Stevens Investors, LLC interests to equity — (2,670) Ending balance $ 22,436 $ 21,822

Information by Business Segme_2

Information by Business Segment (Tables)	9 Months Ended
	Sep. 30, 2024
Segment Reporting [Abstract]
Schedule of Segment Financial Information for Reportable Segments	The table below reports segment financial information for our reportable segments (in thousands): Defense/IT Portfolio Fort Meade/BW Corridor NoVA Defense/IT Lackland Air Force Base Navy Support Redstone Arsenal Data Center Shells Total Defense/IT Portfolio Other Total Three Months Ended September 30, 2024 Revenues from real estate operations $ 80,056 $ 22,083 $ 16,879 $ 8,068 $ 18,332 $ 9,029 $ 154,447 $ 18,116 $ 172,563 Property operating expenses (27,929) (9,252) (9,160) (4,084) (6,463) (1,554) (58,442) (10,439) (68,881) UJV NOI allocable to COPT Defense — — — — — 1,844 1,844 — 1,844 NOI from real estate operations $ 52,127 $ 12,831 $ 7,719 $ 3,984 $ 11,869 $ 9,319 $ 97,849 $ 7,677 $ 105,526 Additions to long-lived assets $ 14,101 $ 5,357 $ 17,034 $ 3,520 $ 1,521 $ — $ 41,533 $ 4,040 $ 45,573 Transfers from non-operating properties $ 418 $ 16 $ — $ 66 $ 25,846 $ 406 $ 26,752 $ 141 $ 26,893 Three Months Ended September 30, 2023 Revenues from real estate operations $ 73,350 $ 20,333 $ 16,193 $ 8,190 $ 13,768 $ 6,811 $ 138,645 $ 17,962 $ 156,607 Property operating expenses (25,216) (7,900) (8,567) (3,933) (4,948) (678) (51,242) (10,546) (61,788) UJV NOI allocable to COPT Defense — — — — — 1,675 1,675 — 1,675 NOI from real estate operations $ 48,134 $ 12,433 $ 7,626 $ 4,257 $ 8,820 $ 7,808 $ 89,078 $ 7,416 $ 96,494 Additions to long-lived assets $ 7,057 $ 4,639 $ — $ 1,201 $ 8,566 $ — $ 21,463 $ 4,567 $ 26,030 Transfers from non-operating properties $ 983 $ 95 $ 51 $ 1 $ 63,025 $ 58,405 $ 122,560 $ 102 $ 122,662 Nine Months Ended September 30, 2024 Revenues from real estate operations $ 235,839 $ 64,110 $ 49,737 $ 24,534 $ 52,157 $ 27,086 $ 453,463 $ 52,848 $ 506,311 Property operating expenses (80,456) (27,444) (26,645) (11,343) (17,976) (4,588) (168,452) (30,585) (199,037) UJV NOI allocable to COPT Defense — — — — — 5,319 5,319 — 5,319 NOI from real estate operations $ 155,383 $ 36,666 $ 23,092 $ 13,191 $ 34,181 $ 27,817 $ 290,330 $ 22,263 $ 312,593 Additions to long-lived assets $ 48,161 $ 19,762 $ 17,034 $ 6,049 $ 2,545 $ — $ 93,551 $ 14,496 $ 108,047 Transfers from non-operating properties $ 2,658 $ 1,011 $ 9 $ 106 $ 60,119 $ 3,891 $ 67,794 $ 1,884 $ 69,678 Segment assets at September 30, 2024 $ 1,447,217 $ 492,912 $ 200,968 $ 161,007 $ 602,573 $ 427,972 $ 3,332,649 $ 314,806 $ 3,647,455 Nine Months Ended September 30, 2023 Revenues from real estate operations $ 215,303 $ 60,003 $ 49,393 $ 24,233 $ 40,160 $ 19,790 $ 408,882 $ 54,359 $ 463,241 Property operating expenses (73,924) (23,155) (26,463) (10,992) (14,334) (2,015) (150,883) (31,925) (182,808) UJV NOI allocable to COPT Defense — — — — — 4,988 4,988 — 4,988 NOI from real estate operations $ 141,379 $ 36,848 $ 22,930 $ 13,241 $ 25,826 $ 22,763 $ 262,987 $ 22,434 $ 285,421 Additions to long-lived assets $ 42,838 $ 14,994 $ 62 $ 2,269 $ 17,339 $ — $ 77,502 $ 12,572 $ 90,074 Transfers from non-operating properties $ 11,392 $ 582 $ 96 $ 2,651 $ 81,352 $ 63,653 $ 159,726 $ 129 $ 159,855 Segment assets at September 30, 2023 $ 1,397,107 $ 486,561 $ 190,344 $ 163,630 $ 548,201 $ 380,366 $ 3,166,209 $ 310,828 $ 3,477,037
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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Segment revenues from real estate operations $ 172,563 $ 156,607 $ 506,311 $ 463,241 Construction contract and other service revenues 16,662 11,949 63,523 42,012 Total revenues $ 189,225 $ 168,556 $ 569,834 $ 505,253
Schedule of Reconciliation of UJV NOI Allocable to CDP to Equity in Income of Unconsolidated Entities	The following table reconciles UJV NOI allocable to COPT Defense to equity in income (loss) of unconsolidated entities as reported on our consolidated statements of operations (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 UJV NOI allocable to COPT Defense $ 1,844 $ 1,675 $ 5,319 $ 4,988 Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense (1,759) (1,743) (5,139) (5,006) Add: Equity in loss of unconsolidated non-real estate entities — — — (3) Equity in income (loss) of unconsolidated entities $ 85 $ (68) $ 180 $ (21)
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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Construction contract and other service revenues $ 16,662 $ 11,949 $ 63,523 $ 42,012 Construction contract and other service expenses (16,127) (11,493) (61,746) (40,249) NOI from service operations $ 535 $ 456 $ 1,777 $ 1,763
Schedule of Reconciliation of Net Operating Income from Real Estate Operations for Reportable Segments and Service Operations to Net Income (Loss)	The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to net income (loss) as reported on our consolidated statements of operations (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 NOI from real estate operations $ 105,526 $ 96,494 $ 312,593 $ 285,421 NOI from service operations 535 456 1,777 1,763 Depreciation and other amortization associated with real estate operations (38,307) (37,620) (114,819) (112,215) Impairment losses — (252,797) — (252,797) General, administrative, leasing and other expenses (11,416) (10,576) (35,195) (31,424) Interest expense (20,376) (17,798) (61,760) (50,759) Interest and other income, net 3,324 2,529 10,330 6,928 Gain on sales of real estate — — — 49,392 Equity in income (loss) of unconsolidated entities 85 (68) 180 (21) UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities (1,844) (1,675) (5,319) (4,988) Income tax expense (130) (152) (312) (467) Net income (loss) $ 37,397 $ (221,207) $ 107,475 $ (109,167)
Schedule of Reconciliation of Segment Assets to Total Assets	The following table reconciles our segment assets to our consolidated total assets (in thousands): September 30, September 30, Segment assets $ 3,647,455 $ 3,477,037 Operating properties lease liabilities included in segment assets 34,012 33,360 Investment in UJV deficit balance included in segment assets 3,370 2,327 Non-operating property assets 314,729 324,168 Other assets 234,736 402,365 Total consolidated assets $ 4,234,302 $ 4,239,257

Construction Contract and Oth_2

Construction Contract and Other Service Revenues (Tables)	9 Months Ended
	Sep. 30, 2024
Revenue from Contract with Customer [Abstract]
Schedule of Construction Contract and Other Service Revenues by Compensation Arrangement	We disaggregate in the table below our construction contract and other service revenues by compensation arrangement as we believe it best depicts the nature, timing and uncertainty of our revenue (in thousands): For the Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Construction contract revenue: Firm fixed price $ 8,158 $ 6,616 $ 29,343 $ 21,898 Guaranteed maximum price 6,318 2,817 28,410 11,561 Cost-plus fee 1,868 2,205 4,574 7,472 Other 318 311 1,196 1,081 $ 16,662 $ 11,949 $ 63,523 $ 42,012
Schedule of Accounts Receivable, Contract Assets and Contract Liabilities	The beginning and ending balances of accounts receivable related to our construction contracts were as follows (in thousands): For the Nine Months Ended September 30, 2024 2023 Beginning balance $ 10,500 $ 7,618 Ending balance $ 3,836 $ 5,367 For the Nine Months Ended September 30, 2024 2023 Beginning balance $ 15,086 $ 22,331 Ending balance $ 22,540 $ 8,356 For the Nine Months Ended September 30, 2024 2023 Beginning balance $ 4,176 $ 2,867 Ending balance $ 2,536 $ 3,938 Portion of beginning balance recognized in revenue during: Three months ended September 30, $ 87 $ 64 Nine months ended September 30, $ 2,198 $ 164

Credit Losses on Financial As_2

Credit Losses on Financial Assets and Other Instruments (Tables)	9 Months Ended
	Sep. 30, 2024
Credit Loss [Abstract]
Schedule of Allowance for Credit Loss	The table below sets forth the activity for our allowance for credit losses for the nine months ended September 30, 2024 and 2023 (in thousands): Investing Receivables Tenant Notes Other Assets (2) Total December 31, 2023 $ 2,377 $ 666 $ 153 $ 3,196 Net credit loss expense (recoveries) (3) 490 57 (51) 496 September 30, 2024 $ 2,867 $ 723 $ 102 $ 3,692 December 31, 2022 $ 2,794 $ 778 $ 268 $ 3,840 Net credit loss expense (recoveries) (3) 829 (64) (88) 677 Write-offs — (33) — (33) September 30, 2023 $ 3,623 $ 681 $ 180 $ 4,484 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of September 30, 2024 and December 31, 2023 included $46,000 and $87,000, respectively, in the line entitled “accounts receivable, net” and $56,000 and $66,000, respectively, in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. (3)
Schedule of Credit Risk Classification	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 September 30, 2024 (in thousands): Origination Year 2019 and Earlier 2020 2021 2022 2023 2024 Total Investing receivables: Credit risk classification: Investment grade $ 69,247 $ 2,656 $ 10,623 $ — $ 632 $ — $ 83,158 Non-investment grade — — — 3,245 — — 3,245 Total $ 69,247 $ 2,656 $ 10,623 $ 3,245 $ 632 $ — $ 86,403 Tenant notes receivable: Credit risk classification: Investment grade $ 591 $ 51 $ — $ — $ — $ — $ 642 Non-investment grade 110 1,333 — — — 446 1,889 Total $ 701 $ 1,384 $ — $ — $ — $ 446 $ 2,531 Sales-type lease receivables: Credit risk classification: Investment grade $ — $ 4,644 $ — $ — $ — $ 965 $ 5,609

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2024
Share-Based Payment Arrangement [Abstract]
Schedule of Restricted Share and TB-PIU Activity	The following table summarizes restricted shares activity under our share-based compensation plans for the nine months ended September 30, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 353,455 $ 25.82 Granted 167,502 $ 24.84 Forfeited (20,980) $ 25.77 Vested (152,642) $ 25.82 Unvested as of September 30, 2024 347,335 $ 25.35 The following table summarizes TB-PIUs activity under our share-based compensation plans for the nine months ended September 30, 2024: Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 194,415 $ 25.76 Granted 127,795 $ 24.57 Vested (93,577) $ 25.63 Unvested as of September 30, 2024 228,633 $ 25.15
Schedule of Payouts for Defined Performance under PB-PIUs	The number of earned awards following the end of the performance period will be determined based on the percentile rank of COPT Defense’s total shareholder return (“TSR”) relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned PB-PIUs 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

Earnings Per Share ("EPS") (Tab

Earnings Per Share ("EPS") (Tables)	9 Months Ended
	Sep. 30, 2024
Earnings Per Share [Abstract]
Schedule 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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Numerator: Net income (loss) attributable to common shareholders $ 36,085 $ (216,187) $ 103,808 $ (107,121) Income attributable to share-based compensation awards for basic EPS (127) (992) (385) (1,093) Numerator for basic EPS on net income (loss) attributable to common shareholders 35,958 (217,179) 103,423 (108,214) Adjustment to income attributable to share-based compensation awards for diluted EPS 23 — 66 — Numerator for diluted EPS on net income (loss) attributable to common shareholders $ 35,981 $ (217,179) $ 103,489 $ (108,214) Denominator (all weighted averages): Denominator for basic EPS (common shares) 112,314 112,196 112,279 112,170 Dilutive effect of share-based compensation awards 696 — 566 — Denominator for diluted EPS (common shares) 113,010 112,196 112,845 112,170 Basic EPS attributable to common shareholders $ 0.32 $ (1.94) $ 0.92 $ (0.96) Diluted EPS attributable to common shareholders $ 0.32 $ (1.94) $ 0.92 $ (0.96)
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 Three Months Ended September 30, For the Nine Months Ended September 30, 2024 2023 2024 2023 Conversion of common units 1,696 1,520 1,675 1,508 Conversion of redeemable noncontrolling interests 747 882 873 980

Organization (Details)

Organization (Details) - 9 months ended Sep. 30, 2024 ft² in Thousands	property	ft²	a	shares
COPT Defense Properties | Preferred Units
Investments in real estate
Limited partners' capital account, units outstanding (in units) | shares				0
COPT Defense Properties, L.P. | COPT Defense Properties | Common Units | COPT Defense Properties
Investments in real estate
Percentage ownership in operating partnership	97.50%
Unconsolidated Real Estate Joint Ventures
Investments in real estate
Number of real estate properties	24
Operating Properties | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	194
Area of real estate property (in sqft or acres) | ft²		22,200
Operating Properties | Greater Washington, DC/Baltimore | Other
Investments in real estate
Number of real estate properties	8
Area of real estate property (in sqft or acres) | ft²		2,100
Operating Properties | Office Properties | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	164
Area of real estate property (in sqft or acres) | ft²		16,500
Operating Properties | Single-tenant data centers | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	30
Area of real estate property (in sqft or acres) | ft²		5,700
Operating Properties | Single-tenant data centers | Unconsolidated Real Estate Joint Ventures | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	24
Properties under development | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	5
Area of real estate property (in sqft or acres) | ft²		831
Properties under development | Office Properties | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	2
Properties under development | Single-tenant data centers | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	3
Land controlled for development | Defense/IT Portfolio
Investments in real estate
Area of real estate property (in sqft or acres)		11,000	1,020
Land controlled for development | Greater Washington, DC/Baltimore | Other
Investments in real estate
Area of real estate property (in sqft or acres) | a			50

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Fair value measurement on a recurring basis $ in Thousands	Sep. 30, 2024 USD ($)
Assets:
Interest rate derivatives	$ 754
Liabilities:
Interest rate derivatives	409
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Interest rate derivatives	0
Liabilities:
Interest rate derivatives	0
Significant Other Observable Inputs (Level 2)
Assets:
Interest rate derivatives	754
Liabilities:
Interest rate derivatives	409
Significant Unobservable  Inputs (Level 3)
Assets:
Interest rate derivatives	0
Liabilities:
Interest rate derivatives	$ 0

Properties, Net - Operating Pro

Properties, Net - Operating Properties, Net (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Operating Properties, Net
Operating properties, net	$ 3,289,959	$ 3,246,806
Operating Properties
Operating Properties, Net
Less: Accumulated depreciation	(1,502,730)	(1,400,162)
Operating properties, net	3,289,959	3,246,806
Operating Properties | Land
Operating Properties, Net
Gross	491,304	482,964
Operating Properties | Buildings and improvements
Operating Properties, Net
Gross	$ 4,301,385	$ 4,164,004

Properties, Net - Narrative (De

Properties, Net - Narrative (Details) ft² in Thousands, $ in Millions	Sep. 26, 2024 USD ($) ft²	Mar. 15, 2024 USD ($) ft²
6841 Benjamin Franklin Drive
Asset Acquisition [Line Items]
Square footage of real estate properties (in square feet) | ft²		202
Asset acquisition, percentage leased		56%
Purchase price | $		$ 15
3900 Rogers Road
Asset Acquisition [Line Items]
Square footage of real estate properties (in square feet) | ft²	80
Purchase price | $	$ 17

Properties, Net - Allocation of

Properties, Net - Allocation of Acquisition Costs (Details) - All acquisitions $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Asset Acquisition [Line Items]
Intangible assets on real estate acquisitions	$ 7,248
Total acquisition cost	32,244
Land, operating properties
Asset Acquisition [Line Items]
Real estate	8,361
Building and improvements
Asset Acquisition [Line Items]
Real estate	$ 16,635

Properties, Net - Intangible as

Properties, Net - Intangible assets Acquired (Details) - All acquisitions $ in Thousands	9 Months Ended
	Sep. 30, 2024 USD ($)
Intangible assets on real estate acquisitions
Intangible assets on real estate acquisitions	$ 7,248
Weighted Average Amortization Period (in Years)	7 years 7 months 6 days
Tenant relationship value
Intangible assets on real estate acquisitions
Intangible assets on real estate acquisitions	$ 3,752
Weighted Average Amortization Period (in Years)	12 years 4 months 24 days
In-place lease value
Intangible assets on real estate acquisitions
Intangible assets on real estate acquisitions	$ 2,229
Weighted Average Amortization Period (in Years)	2 years 4 months 24 days
Above-market leases
Intangible assets on real estate acquisitions
Intangible assets on real estate acquisitions	$ 1,267
Weighted Average Amortization Period (in Years)	2 years 4 months 24 days

Leases - Lease Revenue (Details

Leases - Lease Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Leases [Abstract]
Fixed	$ 129,357	$ 120,408	$ 382,918	$ 354,908
Variable	41,192	34,860	118,683	104,602
Lease revenue	$ 170,549	$ 155,268	$ 501,601	$ 459,510

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	Sep. 30, 2024 USD ($)
Leases [Abstract]
Carrying value of lessee right-of-use asset	$ 43
Operating leases, weighted average remaining lease term	53 years
Operating leases, weighted average discount rate	7.36%
Finance leases, weighted average remaining lease term	8 years
Finance leases, weighted average discount rate	9.14%

Leases - Property Right-of-Use

Leases - Property Right-of-Use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Right-of-use assets
Operating leases - Property	$ 40,523	$ 41,296
Finance leases - Property	2,510	2,565
Total right-of-use assets	$ 43,033	$ 43,861
Finance leases - right-of-use assets, location	Prepaid expenses and other assets, net	Prepaid expenses and other assets, net
Lease liabilities
Operating leases - Property	$ 33,615	$ 33,931
Finance leases - Property	397	415
Total lease liabilities	$ 34,012	$ 34,346
Finance leases, lease liability, location	Other liabilities	Other liabilities

Leases - Property Lease Costs (

Leases - Property Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Operating lease cost
Property leases - fixed	$ 1,929	$ 1,808	$ 5,687	$ 5,146
Property leases - variable	42	17	219	50
Finance lease cost
Amortization of property right-of-use assets	19	18	56	57
Interest on lease liabilities	9	10	28	33
Lease costs	$ 1,999	$ 1,853	$ 5,990	$ 5,286

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ 5,232	$ 4,432
Operating cash flows for financing leases	28	33
Financing cash flows for financing leases	$ 18	$ 14

Leases - Payments Due on Proper

Leases - Payments Due on Property Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Property Operating Leases
2024	$ 1,746
2025	2,589
2026	2,001
2027	2,016
2028	2,032
Thereafter	153,349
Total lease payments	163,733
Less: Amount representing interest	(130,118)
Lease liability	33,615	$ 33,931
Property Finance Leases
2024	15
2025	63
2026	65
2027	67
2028	69
Thereafter	297
Total lease payments	576
Less: Amount representing interest	(179)
Lease liability	$ 397	$ 415

Real Estate Joint Ventures - In

Real Estate Joint Ventures - Investments in Consolidated Real Estate Joint Ventures (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Investments in consolidated real estate joint ventures
Total Assets	$ 4,234,302	$ 4,246,966	$ 4,239,257
Total Liabilities	2,679,271	$ 2,699,631
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	968,333
Total Liabilities	126,541
Variable Interest Entity, Primary Beneficiary | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	91,469
Variable Interest Entity, Primary Beneficiary | Mortgage Debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 69,968
Variable Interest Entity, Primary Beneficiary | LW Redstone Company LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	85%
Total Assets	$ 740,718
Total Liabilities	74,670
Variable Interest Entity, Primary Beneficiary | LW Redstone Company LLC | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	35,023
Variable Interest Entity, Primary Beneficiary | LW Redstone Company LLC | Mortgage Debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 22,227
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	95%
Total Assets	$ 130,342
Total Liabilities	2,599
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	0
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC | Mortgage 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	$ 97,273
Total Liabilities	49,272
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	56,446
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC | Mortgage Debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 47,741

Real Estate Joint Ventures - _2

Real Estate Joint Ventures - Investments in Unconsolidated Real Estate Joint Ventures (Details) $ in Thousands	Sep. 30, 2024 USD ($) property	Dec. 31, 2023 USD ($)
Unconsolidated Real Estate Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	24
Carrying Value of Investment	$ 36,350	$ 38,275
Unconsolidated Real Estate Joint Ventures | Investment in unconsolidated real estate joint ventures
Schedule of Equity Method Investments [Line Items]
Carrying Value of Investment	39,700	41,100
Unconsolidated Real Estate Joint Ventures | Other liabilities
Schedule of Equity Method Investments [Line Items]
Carrying Value of Investment	$ (3,400)	(2,800)
Redshift JV LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	3
Carrying Value of Investment	$ 20,955	21,053
BREIT COPT DC JV LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	9
Carrying Value of Investment	$ 9,781	10,629
Quark JV LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	2
Carrying Value of Investment	$ 6,711	6,727
B RE COPT DC JV III LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	2
Carrying Value of Investment	$ 2,273	2,643
B RE COPT DC JV II LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	8
Carrying Value of Investment	$ (3,370)	(2,777)
Difference between the joint venture's lower cost basis and the entity's share of underlying equity in the net assets	$ 6,700	$ 6,800

Investing Receivables - Investi

Investing Receivables - Investing Receivables (Details) - Investing Receivables - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 86,403	$ 83,889
Allowance for credit losses	(2,867)	(2,377)	$ (3,623)	$ (2,794)
Investing receivables, net	83,536	81,512
Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	83,158	77,022
Other investing loan receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 3,245	$ 6,867

Investing Receivables - Narrati

Investing Receivables - Narrative (Details) - Investing Receivables - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable, net of allowance for credit losses	$ 4.5	$ 6
Notes receivable, fair value disclosure	$ 86	$ 84
Notes receivable from the City of Huntsville | LW Redstone Company LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	9.95%
Other investing loan receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Effective interest rate	14%

Debt, Net - Schedule of Debt (D

Debt, Net - Schedule of Debt (Details)		9 Months Ended
	Sep. 30, 2024 USD ($) extension $ / shares	Sep. 30, 2024 USD ($) extension $ / shares	Dec. 31, 2023 USD ($)
Debt
Carrying Value	$ 2,390,839,000	$ 2,390,839,000	$ 2,416,287,000
Revolving Credit Facility
Debt
Carrying Value	$ 75,000,000	$ 75,000,000	75,000,000
Variable rate, additional spread over SOFR		0.10%
Weighted average interest rate	6.35%	6.35%
Number of extensions | extension	2	2
Extension option period		6 months
Extension fee percentage		0.0625%
Revolving Credit Facility | Minimum
Debt
Variable rate, spread over SOFR		0.725%
Revolving Credit Facility | Maximum
Debt
Variable rate, spread over SOFR		1.40%
Term Loan Facility
Debt
Interest rate	6.60%	6.60%
Carrying Value	$ 124,547,000	$ 124,547,000	124,291,000
Variable rate, additional spread over SOFR		0.10%
Number of extensions | extension	2	2
Extension option period		12 months
Extension fee percentage		0.125%
Term Loan Facility | Minimum
Debt
Variable rate, spread over SOFR		0.85%
Term Loan Facility | Maximum
Debt
Variable rate, spread over SOFR		1.70%
Mortgage and other secured debt
Debt
Carrying Value	$ 69,968,000	$ 69,968,000	99,208,000
Loans payable
Debt
Net deferred financing costs	$ 4,300,000	$ 4,300,000	5,300,000
Fixed-rate mortgage debt | Mortgage and other secured debt
Debt
Interest rate	3.82%	3.82%
Carrying Value	$ 37,391,000	$ 37,391,000	66,314,000
Variable-rate secured debt | Mortgage and other secured debt
Debt
Carrying Value	$ 32,577,000	$ 32,577,000	32,894,000
Variable rate, additional spread over SOFR		0.10%
Weighted average interest rate	6.87%	6.87%
Number of extensions | extension	2	2
Extension option period		12 months
Extension fee percentage		0.10%
Variable-rate secured debt | Mortgage and other secured debt | Interest rate swaps
Debt
Weighted average interest rate	2.44%	2.44%
Variable-rate secured debt | Mortgage and other secured debt | Minimum
Debt
Variable rate, spread over SOFR		1.45%
Variable-rate secured debt | Mortgage and other secured debt | Maximum
Debt
Variable rate, spread over SOFR		1.55%
2.25%, $400,000 aggregate principal | Unsecured Senior Notes
Debt
Interest rate	2.25%	2.25%
Debt instrument, face amount	$ 400,000,000	$ 400,000,000
Carrying Value	398,425,000	398,425,000	397,608,000
Unamortized discounts and/or commissions included in carrying value	$ 1,300,000	$ 1,300,000	1,900,000
Effective interest rate on debt	2.48%	2.48%
5.25%, $345,000 aggregate principal | Unsecured Senior Notes
Debt
Interest rate	5.25%	5.25%
Debt instrument, face amount	$ 345,000,000	$ 345,000,000
Carrying Value	337,132,000	337,132,000	335,802,000
Unamortized discounts and/or commissions included in carrying value	$ 7,000,000	$ 7,000,000	8,100,000
Effective interest rate on debt	5.83%	5.83%
Exchange rate of notes	0.0333882
Exchange price (in dollars per share) | $ / shares	$ 29.95	$ 29.95
2.00%, $400,000 aggregate principal | Unsecured Senior Notes
Debt
Interest rate	2%	2%
Debt instrument, face amount	$ 400,000,000	$ 400,000,000
Carrying Value	397,838,000	397,838,000	397,471,000
Unamortized discounts and/or commissions included in carrying value	$ 1,500,000	$ 1,500,000	1,800,000
Effective interest rate on debt	2.09%	2.09%
2.75%, $600,000 aggregate principal | Unsecured Senior Notes
Debt
Interest rate	2.75%	2.75%
Debt instrument, face amount	$ 600,000,000	$ 600,000,000
Carrying Value	592,048,000	592,048,000	591,212,000
Unamortized discounts and/or commissions included in carrying value	$ 6,900,000	$ 6,900,000	7,600,000
Effective interest rate on debt	2.94%	2.94%
2.90%, $400,000 aggregate principal | Unsecured Senior Notes
Debt
Interest rate	2.90%	2.90%
Debt instrument, face amount	$ 400,000,000	$ 400,000,000
Carrying Value	395,584,000	395,584,000	395,265,000
Unamortized discounts and/or commissions included in carrying value	$ 3,600,000	$ 3,600,000	3,900,000
Effective interest rate on debt	3.01%	3.01%
Unsecured note payable
Debt
Interest rate	0%	0%
Carrying Value	$ 297,000	$ 297,000	430,000
Unamortized discounts and/or commissions included in carrying value	$ 14,000	$ 14,000	$ 32,000

Debt, Net - Narrative (Details)

Debt, Net - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt Disclosure [Abstract]
Interest costs capitalized	$ 712	$ 1,500	$ 1,900	$ 3,500

Debt, Net - Schedule of Interes

Debt, Net - Schedule of Interest Expense (Details) - 5.25%, $345,000 aggregate principal - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Debt
Interest expense at stated interest rate	$ 4,528	$ 956	$ 13,584	$ 956
Interest expense associated with amortization of debt discount and issuance costs	393	124	1,162	124
Total	$ 4,921	$ 1,080	$ 14,746	$ 1,080
Unsecured Senior Notes
Debt
Interest rate	5.25%		5.25%

Debt, Net - Debt Maturities (De

Debt, Net - Debt Maturities (Details) $ in Thousands	Sep. 30, 2024 USD ($)
Schedule on basis of which debt matures
2024	$ 455
2025	23,717
2026	646,300
2027	0
2028	345,000
Thereafter	1,400,000
Total	2,415,472
Net discounts and deferred financing costs	$ 24,600

Debt, Net - Fair Value of Debt

Debt, Net - Fair Value of Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Carrying Amount
Carrying amount and estimated fair value of debt
Long-term debt	$ 2,390,839	$ 2,416,287
Carrying Amount | Unsecured Senior Notes
Carrying amount and estimated fair value of debt
Long-term debt	2,121,027	2,117,358
Carrying Amount | Other fixed-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	37,688	66,744
Carrying Amount | Variable-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	232,124	232,185
Estimated Fair Value
Carrying amount and estimated fair value of debt
Long-term debt	2,238,226	2,172,573
Estimated Fair Value | Unsecured Senior Notes
Carrying amount and estimated fair value of debt
Long-term debt	1,968,894	1,876,611
Estimated Fair Value | Other fixed-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	35,959	63,692
Estimated Fair Value | Variable-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	$ 233,373	$ 232,270

Interest Rate Derivatives - Key

Interest Rate Derivatives - Key Terms and Fair Value of Interest Rate Derivative (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Fair values of interest rate swap derivatives
Fair value of interest rate swaps	$ 345	$ 2,558
Designated | Interest rate swap, effective August 1, 2019
Fair values of interest rate swap derivatives
Notional Amount	$ 10,460
Fixed Rate	1.678%
Floating Rate Index (over SOFR)	0.10%
Fair value of interest rate swaps	$ 343	571
Notional amount of interest rate derivatives after scheduled amortization	10,000
Designated | Interest rate swap, effective April 1, 2020
Fair values of interest rate swap derivatives
Notional Amount	$ 22,250
Fixed Rate	0.573%
Floating Rate Index (over SOFR)	0.10%
Fair value of interest rate swaps	$ 411	1,084
Notional amount of interest rate derivatives after scheduled amortization	22,100
Designated | Interest rate swap, effective February 1, 2023 3.742%
Fair values of interest rate swap derivatives
Notional Amount	$ 150,000
Fixed Rate	3.742%
Fair value of interest rate swaps	$ (304)	681
Designated | Interest rate swap, effective February 1, 2023 3.747%
Fair values of interest rate swap derivatives
Notional Amount	$ 50,000
Fixed Rate	3.747%
Fair value of interest rate swaps	$ (105)	$ 222

Interest Rate Derivatives - Fai

Interest Rate Derivatives - Fair Value and Classification of Interest Rate Derivatives (Details) - Interest rate swaps - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Prepaid expenses and other assets, net
Fair value of interest rate derivatives and balance sheet classification
Interest rate swaps designated as cash flow hedges	$ 754	$ 2,558
Other liabilities
Fair value of interest rate derivatives and balance sheet classification
Interest rate swaps designated as cash flow hedges	$ (409)	$ 0

Interest Rate Derivatives - Eff

Interest Rate Derivatives - Effect of Interest Rate Derivatives on Statement of Operations and Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of (Loss) Income Recognized in AOCI on Derivatives	$ (2,582)	$ 2,042	$ 1,309	$ 6,816
Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations	1,170	1,146	3,522	2,711
Interest rate swaps
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of (Loss) Income Recognized in AOCI on Derivatives	(2,582)	2,042	1,309	6,816
Interest rate swaps | Interest expense
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations	$ 1,170	$ 1,146	$ 3,522	$ 2,711

Interest Rate Derivatives - Nar

Interest Rate Derivatives - Narrative (Details) - Interest rate swaps - Designated $ in Thousands	Sep. 30, 2024 USD ($)
Fair values of interest rate swap derivatives
Approximate amount to be reclassified from AOCL to interest expense over the next 12 months	$ 708
Fair value of derivative liability, excluding the effects of accrued interest and credit valuation adjustments	412
Settlement amount of derivative obligation at termination value	$ 185

Redeemable Noncontrolling Int_3

Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Redeemable Noncontrolling Interest [Roll Forward]
Beginning balance	$ 23,580	$ 26,293
Distributions to noncontrolling interests	(1,446)	(1,971)
Net income attributable to noncontrolling interests	1,446	1,856
Adjustments for changes in fair value of interests	(1,144)	(1,686)
Reclassification of Stevens Investors, LLC interests to equity	0	(2,670)
Ending balance	$ 22,436	$ 21,822

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Equity [Abstract]
At the market, offering program established, aggregate value	$ 300		$ 300
Dividends declared per share (in dollars per share)	$ 0.295	$ 0.285	$ 0.885	$ 0.855
Conversion of common units to common shares (in shares)	40,000		40,000

Information by Business Segme_3

Information by Business Segment - Narrative (Details) - USD ($) $ in Millions	Sep. 30, 2024	Sep. 30, 2023
Unconsolidated real estate joint ventures owning operating properties | Defense/IT Portfolio | Data Center Shells
Segment financial information for real estate operations
Net carrying value of investments	$ 36.4	$ 39.2

Information by Business Segme_4

Information by Business Segment - Segment Financial Information for Our Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Segment financial information for real estate operations
Revenues from real estate operations	$ 189,225	$ 168,556	$ 569,834	$ 505,253
UJV NOI allocable to COPT Defense	1,844	1,675	5,319	4,988
Segment assets	4,234,302	4,239,257	4,234,302	4,239,257	$ 4,246,966
Operating segments
Segment financial information for real estate operations
Segment assets	3,647,455	3,477,037	3,647,455	3,477,037
Real Estate Operations
Segment financial information for real estate operations
Revenues from real estate operations	172,563	156,607	506,311	463,241
Property operating expenses	(68,881)	(61,788)	(199,037)	(182,808)
UJV NOI allocable to COPT Defense	1,844	1,675	5,319	4,988
NOI from real estate operations	105,526	96,494	312,593	285,421
Additions to long-lived assets	45,573	26,030	108,047	90,074
Transfers from non-operating properties	26,893	122,662	69,678	159,855
Real Estate Operations | Defense/IT Portfolio
Segment financial information for real estate operations
Revenues from real estate operations	154,447	138,645	453,463	408,882
Property operating expenses	(58,442)	(51,242)	(168,452)	(150,883)
UJV NOI allocable to COPT Defense	1,844	1,675	5,319	4,988
NOI from real estate operations	97,849	89,078	290,330	262,987
Additions to long-lived assets	41,533	21,463	93,551	77,502
Transfers from non-operating properties	26,752	122,560	67,794	159,726
Real Estate Operations | Defense/IT Portfolio | Fort Meade/BW Corridor
Segment financial information for real estate operations
Revenues from real estate operations	80,056	73,350	235,839	215,303
Property operating expenses	(27,929)	(25,216)	(80,456)	(73,924)
UJV NOI allocable to COPT Defense	0	0	0	0
NOI from real estate operations	52,127	48,134	155,383	141,379
Additions to long-lived assets	14,101	7,057	48,161	42,838
Transfers from non-operating properties	418	983	2,658	11,392
Real Estate Operations | Defense/IT Portfolio | NoVA Defense/IT
Segment financial information for real estate operations
Revenues from real estate operations	22,083	20,333	64,110	60,003
Property operating expenses	(9,252)	(7,900)	(27,444)	(23,155)
UJV NOI allocable to COPT Defense	0	0	0	0
NOI from real estate operations	12,831	12,433	36,666	36,848
Additions to long-lived assets	5,357	4,639	19,762	14,994
Transfers from non-operating properties	16	95	1,011	582
Real Estate Operations | Defense/IT Portfolio | Lackland Air Force Base
Segment financial information for real estate operations
Revenues from real estate operations	16,879	16,193	49,737	49,393
Property operating expenses	(9,160)	(8,567)	(26,645)	(26,463)
UJV NOI allocable to COPT Defense	0	0	0	0
NOI from real estate operations	7,719	7,626	23,092	22,930
Additions to long-lived assets	17,034	0	17,034	62
Transfers from non-operating properties	0	51	9	96
Real Estate Operations | Defense/IT Portfolio | Navy Support
Segment financial information for real estate operations
Revenues from real estate operations	8,068	8,190	24,534	24,233
Property operating expenses	(4,084)	(3,933)	(11,343)	(10,992)
UJV NOI allocable to COPT Defense	0	0	0	0
NOI from real estate operations	3,984	4,257	13,191	13,241
Additions to long-lived assets	3,520	1,201	6,049	2,269
Transfers from non-operating properties	66	1	106	2,651
Real Estate Operations | Defense/IT Portfolio | Redstone Arsenal
Segment financial information for real estate operations
Revenues from real estate operations	18,332	13,768	52,157	40,160
Property operating expenses	(6,463)	(4,948)	(17,976)	(14,334)
UJV NOI allocable to COPT Defense	0	0	0	0
NOI from real estate operations	11,869	8,820	34,181	25,826
Additions to long-lived assets	1,521	8,566	2,545	17,339
Transfers from non-operating properties	25,846	63,025	60,119	81,352
Real Estate Operations | Defense/IT Portfolio | Data Center Shells
Segment financial information for real estate operations
Revenues from real estate operations	9,029	6,811	27,086	19,790
Property operating expenses	(1,554)	(678)	(4,588)	(2,015)
UJV NOI allocable to COPT Defense	1,844	1,675	5,319	4,988
NOI from real estate operations	9,319	7,808	27,817	22,763
Additions to long-lived assets	0	0	0	0
Transfers from non-operating properties	406	58,405	3,891	63,653
Real Estate Operations | Other
Segment financial information for real estate operations
Revenues from real estate operations	18,116	17,962	52,848	54,359
Property operating expenses	(10,439)	(10,546)	(30,585)	(31,925)
UJV NOI allocable to COPT Defense	0	0	0	0
NOI from real estate operations	7,677	7,416	22,263	22,434
Additions to long-lived assets	4,040	4,567	14,496	12,572
Transfers from non-operating properties	141	102	1,884	129
Real Estate Operations | Operating segments
Segment financial information for real estate operations
Segment assets	3,647,455	3,477,037	3,647,455	3,477,037
Real Estate Operations | Operating segments | Defense/IT Portfolio
Segment financial information for real estate operations
Segment assets	3,332,649	3,166,209	3,332,649	3,166,209
Real Estate Operations | Operating segments | Defense/IT Portfolio | Fort Meade/BW Corridor
Segment financial information for real estate operations
Segment assets	1,447,217	1,397,107	1,447,217	1,397,107
Real Estate Operations | Operating segments | Defense/IT Portfolio | NoVA Defense/IT
Segment financial information for real estate operations
Segment assets	492,912	486,561	492,912	486,561
Real Estate Operations | Operating segments | Defense/IT Portfolio | Lackland Air Force Base
Segment financial information for real estate operations
Segment assets	200,968	190,344	200,968	190,344
Real Estate Operations | Operating segments | Defense/IT Portfolio | Navy Support
Segment financial information for real estate operations
Segment assets	161,007	163,630	161,007	163,630
Real Estate Operations | Operating segments | Defense/IT Portfolio | Redstone Arsenal
Segment financial information for real estate operations
Segment assets	602,573	548,201	602,573	548,201
Real Estate Operations | Operating segments | Defense/IT Portfolio | Data Center Shells
Segment financial information for real estate operations
Segment assets	427,972	380,366	427,972	380,366
Real Estate Operations | Operating segments | Other
Segment financial information for real estate operations
Segment assets	$ 314,806	$ 310,828	$ 314,806	$ 310,828

Information by Business Segme_5

Information by Business Segment - Reconciliation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reconciliation of segment revenues to total revenues
Total revenues	$ 189,225	$ 168,556	$ 569,834	$ 505,253
Construction contract and other service revenues	16,662	11,949	63,523	42,012
Real Estate Operations
Reconciliation of segment revenues to total revenues
Total revenues	$ 172,563	$ 156,607	$ 506,311	$ 463,241

Information by Business Segme_6

Information by Business Segment - Reconciliation of UJV NOI to Equity in Income (Loss) of Unconsolidated Entities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Reconciliation of UJV NOI allocable to COPT to equity income (loss) in unconsolidated entities
UJV NOI allocable to COPT Defense	$ 1,844	$ 1,675	$ 5,319	$ 4,988
Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense	(1,759)	(1,743)	(5,139)	(5,006)
Add: Equity in loss of unconsolidated non-real estate entities	0	0	0	(3)
Equity in income (loss) of unconsolidated entities	$ 85	$ (68)	$ 180	$ (21)

Information by Business Segme_7

Information by Business Segment - Computation of NOI from Service Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment financial information for real estate operations
Construction contract and other service revenues	$ 16,662	$ 11,949	$ 63,523	$ 42,012
Construction contract and other service expenses	(16,127)	(11,493)	(61,746)	(40,249)
Service Operations
Segment financial information for real estate operations
NOI from service operations	$ 535	$ 456	$ 1,777	$ 1,763

Information by Business Segme_8

Information by Business Segment - Reconciliation of NOI from Real Estate Operations and NOI from Service Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment financial information for real estate operations
Depreciation and other amortization associated with real estate operations	$ (38,307)	$ (37,620)	$ (114,819)	$ (112,215)
Impairment losses	0	(252,797)	0	(252,797)
General, administrative, leasing and other expenses	(11,416)	(10,576)	(35,195)	(31,424)
Interest expense	(20,376)	(17,798)	(61,760)	(50,759)
Interest and other income, net	3,324	2,529	10,330	6,928
Gain on sales of real estate	0	0	0	49,392
Equity in income (loss) of unconsolidated entities	85	(68)	180	(21)
UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities	(1,844)	(1,675)	(5,319)	(4,988)
Income tax expense	(130)	(152)	(312)	(467)
Net income (loss)	37,397	(221,207)	107,475	(109,167)
Real Estate Operations
Segment financial information for real estate operations
NOI from real estate operations	105,526	96,494	312,593	285,421
UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities	(1,844)	(1,675)	(5,319)	(4,988)
Service Operations
Segment financial information for real estate operations
NOI from service operations	$ 535	$ 456	$ 1,777	$ 1,763

Information by Business Segme_9

Information by Business Segment - Reconciliation of Segment Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023
Reconciliation of segment assets to total assets
Total consolidated assets	$ 4,234,302	$ 4,246,966	$ 4,239,257
Operating properties lease liabilities included in segment assets	34,012	$ 34,346
Operating segments
Reconciliation of segment assets to total assets
Total consolidated assets	3,647,455		3,477,037
Operating properties lease liabilities included in segment assets	34,012		33,360
Operating segments | Investment in UJV with deficit balance
Reconciliation of segment assets to total assets
Investment in UJV deficit balance included in segment assets	3,370		2,327
Non-operating property assets
Reconciliation of segment assets to total assets
Total consolidated assets	314,729		324,168
Other assets
Reconciliation of segment assets to total assets
Total consolidated assets	$ 234,736		$ 402,365

Construction Contract and Oth_3

Construction Contract and Other Service Revenues - Construction Contracts and Other Service Revenues by Compensation Arrangement and Service Type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 16,662	$ 11,949	$ 63,523	$ 42,012
Firm fixed price
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	8,158	6,616	29,343	21,898
Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	6,318	2,817	28,410	11,561
Cost-plus fee
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	1,868	2,205	4,574	7,472
Other
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 318	$ 311	$ 1,196	$ 1,081

Construction Contract and Oth_4

Construction Contract and Other Service Revenues - Schedule of Accounts Receivable, Contract Asset and Contract Liability (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Change in Accounts Receivable
Beginning balance			$ 48,946
Ending balance	$ 42,240		42,240
Construction Contract Revenue
Change in Accounts Receivable
Beginning balance			10,500	$ 7,618
Ending balance	3,836	$ 5,367	3,836	5,367
Change in Contract with Customer, Asset
Beginning balance			15,086	22,331
Ending balance	22,540	8,356	22,540	8,356
Change in Contract with Customer, Liability
Beginning balance			4,176	2,867
Ending balance	2,536	3,938	2,536	3,938
Portion of beginning balance recognized in revenue	$ 87	$ 64	$ 2,198	$ 164

Construction Contract and Oth_5

Construction Contract and Other Service Revenues - Narrative (Details) - Construction Contract Revenue - USD ($)	Sep. 30, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Remaining performance obligations	$ 22,700,000
Deferred incremental costs	$ 0	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-10-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	3 months

Credit Losses on Financial As_3

Credit Losses on Financial Assets and Other Instruments - Allowance for Credit Loss (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Beginning balance	$ 3,196	$ 3,840
Net credit loss expense (recoveries)	496	677
Write-offs		(33)
Ending balance	3,692	4,484
Other Assets
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	153	268
Net credit loss expense (recoveries)	(51)	(88)
Write-offs		0
Ending balance	102	180
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	102	180
Other Assets | Accounts Receivable, Net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	87
Ending balance	46
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	46
Other Assets | Prepaid expenses and other assets, net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	66
Ending balance	56
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	56
Investing Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,377	2,794
Net credit loss expense (recoveries)	490	829
Write-offs		0
Ending balance	2,867	3,623
Tenant Notes Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	666	778
Net credit loss expense (recoveries)	57	(64)
Write-offs		(33)
Ending balance	$ 723	$ 681

Credit Losses on Financial As_4

Credit Losses on Financial Assets and Other Instruments - Credit Risk Classification (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Investing Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	$ 69,247
2020	2,656
2021	10,623
2022	3,245
2023	632
2024	0
Total	86,403	$ 83,889
Investing Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	69,247
2020	2,656
2021	10,623
2022	0
2023	632
2024	0
Total	83,158
Investing Receivables | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	0
2020	0
2021	0
2022	3,245
2023	0
2024	0
Total	3,245
Tenant notes receivable:
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	701
2020	1,384
2021	0
2022	0
2023	0
2024	446
Total	2,531
Tenant notes receivable: | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	591
2020	51
2021	0
2022	0
2023	0
2024	0
Total	642
Tenant notes receivable: | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	110
2020	1,333
2021	0
2022	0
2023	0
2024	446
Total	1,889
Sales-type lease receivables: | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	0
2020	4,644
2021	0
2022	0
2023	0
2024	965
Total	$ 5,609

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Shares and TB-PIUs Activity (Details)	9 Months Ended
	Sep. 30, 2024 $ / shares shares
Restricted shares
Number of Shares
Unvested at the beginning of the period (in shares or units) | shares	353,455
Granted (in shares or units) | shares	167,502
Forfeited (in shares or units) | shares	(20,980)
Vested (in shares or units) | shares	(152,642)
Unvested at the end of the period (in shares or units) | shares	347,335
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share or unit) | $ / shares	$ 25.82
Granted (in dollars per share or unit) | $ / shares	24.84
Forfeited (in dollars per share or unit) | $ / shares	25.77
Vested (in dollars per share or unit) | $ / shares	25.82
Unvested at the end of the period (in dollars per share or unit) | $ / shares	$ 25.35
Time-based PIU's
Number of Shares
Unvested at the beginning of the period (in shares or units) | shares	194,415
Granted (in shares or units) | shares	127,795
Vested (in shares or units) | shares	(93,577)
Unvested at the end of the period (in shares or units) | shares	228,633
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share or unit) | $ / shares	$ 25.76
Granted (in dollars per share or unit) | $ / shares	24.57
Vested (in dollars per share or unit) | $ / shares	25.63
Unvested at the end of the period (in dollars per share or unit) | $ / shares	$ 25.15

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands			9 Months Ended
	Feb. 01, 2024 shares	Jan. 01, 2024 USD ($) percentile_rank $ / shares shares	Sep. 30, 2024 USD ($) form $ / shares shares
Restricted shares
Share-Based Compensation
Aggregate intrinsic value of awards upon vesting | $			$ 3,700
Granted (in shares or units) | shares			167,502
Granted (in dollars per share or unit) | $ / shares			$ 24.84
PIUs
Share-Based Compensation
Number of forms of profit interest units | form			2
Time-based PIU's
Share-Based Compensation
Aggregate intrinsic value of awards upon vesting | $			$ 2,300
Granted (in shares or units) | shares			127,795
Granted (in dollars per share or unit) | $ / shares			$ 24.57
Performance-based PIU's
Share-Based Compensation
The number of percentile ranks to fall between to earn interpolated PB-PIUs between such percentile ranks, conditioned on the percentile rank exceeding 25% | percentile_rank		2
Payout percentage reduction when TSR percentile rank exceeds target and TSR is negative		12.50%
Minimum payout percentage if TSR percentile rank exceeds the 50th percentile and TSR is negative		50%
Minimum payout percentage if TSR is at least 10%		50%
Minimum payout percentage if TSR is at least 6%		25%
Percent of award distribution rights		10%
Award performance period		3 years
Aggregate grant date fair value | $		$ 5,400
Baseline value per common share (in dollars per share) | $ / shares		$ 25.63
Expected volatility of common shares		25.90%
Risk-free interest rate		4.13%
Performance-based PIU's | Target Level
Share-Based Compensation
Granted (in dollars per share or unit) | $ / shares		$ 36.06
Performance-based PIU's | Senior Management Team Members
Share-Based Compensation
Granted (in shares or units) | shares		299,766
Award vesting period		3 years
Performance-based PIU's | Executives | 2021 PB PIU
Share-Based Compensation
Units issued for awards vested in period (in units) | shares	211,845
Deferred share awards
Share-Based Compensation
Granted (in shares or units) | shares			8,796
Aggregate grant date fair value | $			$ 217
Granted (in dollars per share or unit) | $ / shares			$ 24.66

Share-Based Compensation - Sche

Share-Based Compensation - Schedule of Payouts for Defined Performance under PB-PIUs (Details) - Performance-based PIU's	Jan. 01, 2024
Potential earned PSUs payout for defined levels of performance under awards
Earned PB-PIUs payout granted on 75th or greater percentile rank	100%
Earned PB-PIUs payout granted on 50th percentile rank	50%
Earned PB-PIUs payout granted on 25th percentile rank	25%
Earned PB-PIUs payout granted on percentile rank below 25th	0%

Earnings Per Share ("EPS") - Sc

Earnings Per Share ("EPS") - Schedule of Calculation Of Numerator and Denominator in Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net income (loss) attributable to common shareholders	$ 36,085	$ (216,187)	$ 103,808	$ (107,121)
Income attributable to share-based compensation awards for basic EPS	(127)	(992)	(385)	(1,093)
Numerator for basic EPS on net income (loss) attributable to common shareholders	35,958	(217,179)	103,423	(108,214)
Adjustment to income attributable to share-based compensation awards for diluted EPS	23	0	66	0
Numerator for diluted EPS on net (loss) income attributable to common shareholders	$ 35,981	$ (217,179)	$ 103,489	$ (108,214)
Denominator (all weighted averages):
Denominator for basic EPS (common shares) (in shares)	112,314	112,196	112,279	112,170
Dilutive effect of share-based compensation awards (in shares)	696	0	566	0
Denominator for diluted EPS (common shares) (in shares)	113,010	112,196	112,845	112,170
Basic EPS attributable to common shareholders (in dollars per share)	$ 0.32	$ (1.94)	$ 0.92	$ (0.96)
Diluted EPS attributable to common shareholders (in dollars per share)	$ 0.32	$ (1.94)	$ 0.92	$ (0.96)

Earnings Per Share ("EPS") - _2

Earnings Per Share ("EPS") - Schedule of Securities Excluded From Computation Of Diluted Earnings Per Share (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Conversion of common units
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	1,696	1,520	1,675	1,508
Conversion of redeemable noncontrolling interests
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	747	882	873	980

Earnings Per Share ("EPS") - Na

Earnings Per Share ("EPS") - Narrative (Details) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Weighted average restricted shares and deferred shares
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	436	423	433	411
Weighted average TB-PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	229	171	221	174
Weighted Average Vested PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	223	170	212	148
Weighted Average PB-PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	718	608	740	636

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Sep. 30, 2024 USD ($) property
Commitments and Contingencies
Estimate of possible loss (up to)	$ 4.8
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	$ 25