COPT Defense Properties (CDP) 10-Q 1 May 24 2024 Q1 Quarterly report Financial data

Cover

Cover - shares	3 Months Ended
	Mar. 31, 2024	Apr. 22, 2024
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 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		112,634,870
Entity Central Index Key	0000860546
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	Q1
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Properties, net:
Operating properties, net	$ 3,272,452	$ 3,246,806
Projects in development or held for future development	245,426	256,872
Total properties, net	3,517,878	3,503,678
Property - operating right-of-use assets	40,368	41,296
Cash and cash equivalents	123,144	167,820
Investment in unconsolidated real estate joint ventures	40,597	41,052
Accounts receivable, net	50,088	48,946
Deferred rent receivable	153,788	149,237
Lease incentives, net	61,150	61,331
Deferred leasing costs (net of accumulated amortization of $41,846 and $41,448, respectively)	70,902	70,057
Prepaid expenses and other assets, net	92,457	82,037
Total assets	4,232,895	4,246,966
Liabilities:
Debt, net	2,416,873	2,416,287
Accounts payable and accrued expenses	111,981	133,315
Rents received in advance and security deposits	37,557	35,409
Dividends and distributions payable	33,906	32,644
Deferred revenue associated with operating leases	34,019	29,049
Property - operating lease liabilities	33,141	33,931
Other liabilities	16,406	18,996
Total liabilities	2,683,883	2,699,631
Commitments and contingencies (Note 17)
Redeemable noncontrolling interests	22,966	23,580
Shareholders’ equity:
Common Shares of beneficial interest ($0.01 par value; 150,000,000 shares authorized; shares issued and outstanding of 112,640,861 at March 31, 2024 and 112,555,352 at December 31, 2023)	1,126	1,126
Additional paid-in capital	2,487,468	2,489,989
Cumulative distributions in excess of net income	(1,009,964)	(1,009,318)
Accumulated other comprehensive income	3,849	2,115
Total shareholders’ equity	1,482,479	1,483,912
Noncontrolling interests in subsidiaries:
Common units in COPT Defense Properties, L.P. (“CDPLP”)	29,214	25,502
Other consolidated entities	14,353	14,341
Noncontrolling interests in subsidiaries	43,567	39,843
Total equity	1,526,046	1,523,755
Total liabilities, redeemable noncontrolling interests and equity	4,232,895	4,246,966
Investing Receivables
Properties, net:
Investing receivables (net of allowance for credit losses of $2,361 and $2,377, respectively)	$ 82,523	$ 81,512

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accumulated amortization of deferred leasing costs	$ 41,846	$ 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)	112,640,861	112,555,352
Common shares of beneficial interest, shares outstanding (in shares)	112,640,861	112,555,352
Investing Receivables
Investing receivable allowance for credit loss	$ 2,361	$ 2,377

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues
Lease revenue	$ 165,433	$ 150,560
Other property revenue	1,230	1,121
Construction contract and other service revenues	26,603	15,820
Total revenues	193,266	167,501
Operating expenses
Property operating expenses	66,746	59,420
Depreciation and amortization associated with real estate operations	38,351	36,995
Construction contract and other service expenses	26,007	15,201
General, administrative, leasing and other expenses	11,747	10,490
Total operating expenses	142,851	122,106
Interest expense	(20,767)	(16,442)
Interest and other income, net	4,122	2,256
Gain on sales of real estate	0	49,378
Income before equity in income (loss) of unconsolidated entities and income taxes	33,770	80,587
Equity in income (loss) of unconsolidated entities	69	(64)
Income tax expense	(168)	(125)
Net income	33,671	80,398
Net income attributable to noncontrolling interests:
Common units in CDPLP	(608)	(1,293)
Other consolidated entities	(454)	(326)
Net income attributable to common shareholders	$ 32,609	$ 78,779
Earnings per common share:
Net income attributable to common shareholders - basic (in dollars per share)	$ 0.29	$ 0.70
Net income attributable to common shareholders - diluted (in dollars per share)	$ 0.29	$ 0.70

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income	$ 33,671	$ 80,398
Other comprehensive income (loss):
Unrealized income (loss) on interest rate derivatives	2,981	(215)
Reclassification adjustments on interest rate derivatives recognized in interest expense	(1,180)	(591)
Total other comprehensive income (loss)	1,801	(806)
Comprehensive income	35,472	79,592
Comprehensive income attributable to noncontrolling interests	(1,129)	(1,531)
Comprehensive income attributable to common shareholders	$ 34,343	$ 78,061

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	(373)					(373)
Share-based compensation issued, net of redemptions	1,814	1	1,059			754
Redemption of vested equity awards	(1,113)		(1,113)
Adjustments to noncontrolling interests resulting from changes in ownership of CDPLP	0		(2,342)			2,342
Comprehensive income	78,893			78,779	(718)	832
Dividends	(32,091)			(32,091)
Distributions to owners of common units in CDPLP	(544)					(544)
Distributions to noncontrolling interests in other consolidated entities	(8)					(8)
Adjustments for changes in fair value of redeemable noncontrolling interests	781		781
Balance at Mar. 31, 2023	1,768,814	1,125	2,484,501	(760,820)	1,353	42,655
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
Redemption of common units	(1,180)					(1,180)
Share-based compensation issued, net of redemptions	2,810		1,158			1,652
Redemption of vested equity awards	(1,039)		(1,039)
Adjustments to noncontrolling interests resulting from changes in ownership of CDPLP	0		(3,255)			3,255
Comprehensive income	35,003			32,609	1,734	660
Dividends	(33,255)			(33,255)
Distributions to owners of common units in CDPLP	(655)					(655)
Distributions to noncontrolling interests in other consolidated entities	(8)					(8)
Adjustments for changes in fair value of redeemable noncontrolling interests	615		615
Balance at Mar. 31, 2024	$ 1,526,046	$ 1,126	$ 2,487,468	$ (1,009,964)	$ 3,849	$ 43,567

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - shares	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Statement of Stockholders' Equity [Abstract]
Common shares outstanding (in shares)	112,640,861	112,513,857
Share-based compensation issued, net of redemptions (in shares)	85,509	89,964

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Revenues from real estate operations received	$ 173,830	$ 152,273
Construction contract and other service revenues received	11,445	18,765
Property operating expenses paid	(58,314)	(55,753)
Construction contract and other service expenses paid	(18,894)	(21,999)
General, administrative, leasing and other expenses paid	(11,828)	(11,681)
Interest expense paid	(20,996)	(12,031)
Lease incentives paid	(6,578)	(10,350)
Interest and other income received	3,551	1,316
Other	(1,226)	(1,795)
Net cash provided by operating activities	70,990	58,745
Cash flows from investing activities
Acquisitions of operating properties and related intangible assets	(15,210)	0
Development of properties	(39,932)	(71,282)
Tenant improvements on operating properties	(7,946)	(22,568)
Other capital improvements on operating properties	(13,084)	(5,512)
Proceeds from sale of properties	0	189,325
Leasing costs paid	(2,666)	(4,655)
Other	(73)	(125)
Net cash (used in) provided by investing activities	(78,911)	85,183
Proceeds from debt
Revolving Credit Facility	0	95,000
Repayments of debt
Revolving Credit Facility	0	(188,000)
Scheduled principal amortization	(769)	(790)
Other debt repayments	0	(15,902)
Common share dividends paid	(32,104)	(30,941)
Other	(3,546)	(2,900)
Net cash used in financing activities	(36,419)	(143,533)
Net (decrease) increase in cash and cash equivalents and restricted cash	(44,340)	395
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	125,084	16,904
Reconciliation of net income to net cash provided by operating activities:
Net income	33,671	80,398
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and other amortization	38,959	37,597
Amortization of deferred financing costs and net debt discounts	1,699	1,250
Change in net deferred rent receivable and liability	496	(6,869)
Gain on sales of real estate	0	(49,378)
Share-based compensation	2,645	1,733
Other	(178)	(376)
Changes in operating assets and liabilities:
Increase in accounts receivable	(1,303)	(2,802)
(Increase) decrease in lease incentives and prepaid expenses and other assets, net	(2,498)	9,361
Decrease in accounts payable, accrued expenses and other liabilities	(4,649)	(16,806)
Increase in rents received in advance and security deposits	2,148	4,637
Net cash provided by operating activities	70,990	58,745
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	123,144	15,199
Restricted cash at end of period	1,940	1,705
Cash and cash equivalents and restricted cash at end of period	125,084	16,904
Supplemental schedule of non-cash investing and financing activities:
Decrease in accrued capital improvements, leasing and other investing activity costs	(19,113)	(11,043)
Recognition of operating right-of-use assets and related lease liabilities	277	6,697
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
Increase (decrease) in fair value of derivatives applied to accumulated other comprehensive income and noncontrolling interests	1,801	(806)
Dividends/distributions payable	33,906	32,630
Adjustments to noncontrolling interests resulting from changes in CDPLP ownership	3,255	2,342
Decrease in redeemable noncontrolling interests and increase in equity to adjust for changes in fair value of redeemable noncontrolling interests	$ (615)	$ (781)

Organization

Organization	3 Months Ended
	Mar. 31, 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 March 31, 2024, our Defense/IT Portfolio included: • 193 operating properties totaling 22.0 million square feet comprised of 16.3 million square feet in 163 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; • six properties under development (three office properties and three data center shells), including one partially-operational property, that will total approximately 959,000 square feet upon completion; and • approximately 650 acres of land controlled that we believe could be developed into approximately 7.7 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 March 31, 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 March 31, 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	3 Months Ended
	Mar. 31, 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. We are currently assessing the impact of this guidance on our future related disclosures. 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 are currently assessing the application of this guidance on our future related disclosures.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Recurring Fair Value Measurements We have a non-qualified elective deferred compensation plan for Trustees and certain members of our management team that, prior to December 31, 2019, permitted participants to defer up to 100% of their compensation on a pre-tax basis and receive a tax-deferred return on such deferrals. Effective December 31, 2019, no new investments of deferred compensation were eligible for the plan. The assets held in the plan (comprised of mutual funds) and the corresponding liability to the participants are measured at fair value on a recurring basis on our consolidated balance sheets using quoted market prices. The balance of the plan, which was fully funded and totaled $2.0 million as of March 31, 2024, is included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. The offsetting liability associated with the plan is adjusted to fair value at the end of each accounting period based on the fair value of the plan assets and reported in “other liabilities” on our consolidated balance sheets. The assets of the plan are classified in Level 1 of the fair value hierarchy, while the offsetting liability is classified in Level 2 of the fair value hierarchy. The fair values of our interest rate derivatives, 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 March 31, 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 March 31, 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) Marketable securities in deferred compensation plan $ 1,959 $ — $ — $ 1,959 Interest rate derivatives — 4,359 — 4,359 Total assets $ 1,959 $ 4,359 $ — $ 6,318 Liabilities: (2) Deferred compensation plan liability $ — $ 1,959 $ — $ 1,959 (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	3 Months Ended
	Mar. 31, 2024
Real Estate [Abstract]
Properties, Net	Properties, Net Operating properties, net consisted of the following (in thousands): March 31, December 31, Land $ 488,371 $ 482,964 Buildings and improvements 4,218,702 4,164,004 Less: Accumulated depreciation (1,434,621) (1,400,162) Operating properties, net $ 3,272,452 $ 3,246,806 On March 15, 2024, we acquired 6841 Benjamin Franklin Drive, a 202,000 square foot operating office 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. The table below sets forth the allocation of the purchase price and transaction costs associated with this acquisition (in thousands): Land, operating properties $ 5,428 Building and improvements 2,534 Intangible assets on real estate acquisitions 7,248 Total acquisition cost $ 15,210 Intangible assets recorded in connection with this acquisition 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	3 Months Ended
	Mar. 31, 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 March 31, Lease revenue 2024 2023 Fixed $ 126,198 $ 116,039 Variable 39,235 34,521 $ 165,433 $ 150,560 Lessee Arrangements As of March 31, 2024, our balance sheet included $42.9 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 March 31, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,368 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,547 2,565 Total right-of-use assets $ 42,915 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,141 $ 33,931 Finance leases - Property Other liabilities 409 415 Total lease liabilities $ 33,550 $ 34,346 As of March 31, 2024, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.32%, while our finance leases had a weighted average remaining lease term of nine 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 March 31, Lease cost 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,859 $ 1,535 Property leases - variable Property operating expenses 34 17 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 20 Interest on lease liabilities Interest expense 9 13 $ 1,921 $ 1,585 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Three Months Ended March 31, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 1,724 $ 1,185 Operating cash flows for financing leases $ 9 $ 13 Financing cash flows for financing leases $ 6 $ 4 Payments on property leases were due as follows (in thousands): March 31, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 5,099 $ 46 2025 2,403 63 2026 1,815 65 2027 1,830 66 2028 1,847 69 Thereafter 139,906 297 Total lease payments 152,900 606 Less: Amount representing interest (119,759) (197) Lease liability $ 33,141 $ 409 (1) Represents the nine 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 March 31, Lease revenue 2024 2023 Fixed $ 126,198 $ 116,039 Variable 39,235 34,521 $ 165,433 $ 150,560 Lessee Arrangements As of March 31, 2024, our balance sheet included $42.9 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 March 31, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,368 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,547 2,565 Total right-of-use assets $ 42,915 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,141 $ 33,931 Finance leases - Property Other liabilities 409 415 Total lease liabilities $ 33,550 $ 34,346 As of March 31, 2024, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.32%, while our finance leases had a weighted average remaining lease term of nine 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 March 31, Lease cost 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,859 $ 1,535 Property leases - variable Property operating expenses 34 17 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 20 Interest on lease liabilities Interest expense 9 13 $ 1,921 $ 1,585 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Three Months Ended March 31, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 1,724 $ 1,185 Operating cash flows for financing leases $ 9 $ 13 Financing cash flows for financing leases $ 6 $ 4 Payments on property leases were due as follows (in thousands): March 31, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 5,099 $ 46 2025 2,403 63 2026 1,815 65 2027 1,830 66 2028 1,847 69 Thereafter 139,906 297 Total lease payments 152,900 606 Less: Amount representing interest (119,759) (197) Lease liability $ 33,141 $ 409 (1) Represents the nine 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 March 31, Lease revenue 2024 2023 Fixed $ 126,198 $ 116,039 Variable 39,235 34,521 $ 165,433 $ 150,560 Lessee Arrangements As of March 31, 2024, our balance sheet included $42.9 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 March 31, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,368 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,547 2,565 Total right-of-use assets $ 42,915 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,141 $ 33,931 Finance leases - Property Other liabilities 409 415 Total lease liabilities $ 33,550 $ 34,346 As of March 31, 2024, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.32%, while our finance leases had a weighted average remaining lease term of nine 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 March 31, Lease cost 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,859 $ 1,535 Property leases - variable Property operating expenses 34 17 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 20 Interest on lease liabilities Interest expense 9 13 $ 1,921 $ 1,585 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Three Months Ended March 31, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 1,724 $ 1,185 Operating cash flows for financing leases $ 9 $ 13 Financing cash flows for financing leases $ 6 $ 4 Payments on property leases were due as follows (in thousands): March 31, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 5,099 $ 46 2025 2,403 63 2026 1,815 65 2027 1,830 66 2028 1,847 69 Thereafter 139,906 297 Total lease payments 152,900 606 Less: Amount representing interest (119,759) (197) Lease liability $ 33,141 $ 409 (1) Represents the nine months ending December 31, 2024.

Real Estate Joint Ventures

Real Estate Joint Ventures	3 Months Ended
	Mar. 31, 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 March 31, 2024 pertaining to our investments in consolidated real estate joint ventures, which are each variable interest entities (dollars in thousands): Nominal Ownership % March 31, 2024 Date Formed Total Encumbered Assets Total Liabilities Mortgage Debt Entity Location LW Redstone Company, LLC (1) 3/23/2010 85% Huntsville, Alabama $ 723,509 $ 98,418 $ 98,619 $ 50,205 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 130,123 — 3,579 — M Square Associates, LLC 6/26/2007 50% College Park, Maryland 98,456 56,944 50,317 48,337 $ 952,088 $ 155,362 $ 152,515 $ 98,542 (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 March 31, December 31, Redshift JV LLC 1/10/2023 10% 3 $ 21,021 $ 21,053 BREIT COPT DC JV LLC 6/20/2019 10% 9 10,321 10,629 Quark JV LLC 12/14/2022 10% 2 6,722 6,727 B RE COPT DC JV III LLC 6/2/2021 10% 2 2,533 2,643 B RE COPT DC JV II LLC (2) 10/30/2020 10% 8 (2,982) (2,777) 24 $ 37,615 $ 38,275 (1) Included $40.6 million and $41.1 million reported in “investment in unconsolidated real estate joint ventures” and $3.0 million and $2.8 million for investments with deficit balances reported in “other liabilities” on our consolidated balance sheets as of March 31, 2024 and December 31, 2023, respectively. (2)

Investing Receivables

Investing Receivables	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
Investing Receivables	Investing Receivables Investing receivables consisted of the following (in thousands): March 31, December 31, Notes receivable from the City of Huntsville $ 78,017 $ 77,022 Other investing loan receivable 6,867 6,867 Amortized cost basis 84,884 83,889 Allowance for credit losses (2,361) (2,377) Investing receivables, net $ 82,523 $ 81,512 The balances above include accrued interest receivable, net of allowance for credit losses, of $822,000 as of March 31, 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 March 31, 2024 carries a stated interest rate of 12.0% and matures in 2024. The fair value of these receivables was approximately $85 million as of March 31, 2024 and $84 million as of December 31, 2023.

Debt, Net

Debt, Net	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Debt, Net	Debt, Net Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of March 31, 2024 March 31, December 31, Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed-rate mortgage debt $ 65,753 $ 66,314 3.82% to 4.62% (2) 2024-2026 Variable-rate secured debt 32,789 32,894 SOFR + 0.10% + 1.45% to 1.55% (3) 2025-2026 (4) Total mortgage and other secured debt 98,542 99,208 Revolving Credit Facility 75,000 75,000 SOFR + 0.10% + 0.725% to 1.400% (5) October 2026 (6) Term Loan Facility 124,376 124,291 SOFR + 0.10% + 0.850% to 1.700% (7) January 2026 (8) Unsecured Senior Notes 2.25%, $400,000 aggregate principal 397,879 397,608 2.25% (9) March 2026 5.25%, $345,000 aggregate principal (10) 336,237 335,802 5.25% (11) September 2028 2.00%, $400,000 aggregate principal 397,593 397,471 2.00% (12) January 2029 2.75%, $600,000 aggregate principal 591,489 591,212 2.75% (13) April 2031 2.90%, $400,000 aggregate principal 395,371 395,265 2.90% (14) December 2033 Unsecured note payable 386 430 0% (15) May 2026 Total debt, net $ 2,416,873 $ 2,416,287 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $5.0 million as of March 31, 2024 and $5.3 million as of December 31, 2023. (2) The weighted average interest rate on our fixed-rate mortgage debt was 4.10% as of March 31, 2024. (3) 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 March 31, 2024 was 2.45%; excluding the effect of these swaps, the weighted average interest rate on this debt as of March 31, 2024 was 6.93%. (4) 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. (5) The weighted average interest rate on the Revolving Credit Facility was 6.48% as of March 31, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (6) 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. (7) The interest rate on this loan was 6.73% as of March 31, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (8) 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. (9) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.7 million as of March 31, 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%. (10) 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 March 31, 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). (11) The carrying value of these notes reflects unamortized commissions totaling $7.7 million as of March 31, 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%. (12) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.7 million as of March 31, 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%. (13) The carrying value of these notes reflects unamortized discounts and commissions totaling $7.4 million as of March 31, 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%. (14) The carrying value of these notes reflects unamortized discounts and commissions totaling $3.8 million as of March 31, 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%. (15) 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 $25,000 as of March 31, 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 March 31, 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 months ended March 31, 2024 (in thousands): Interest expense at stated interest rate $ 4,528 Interest expense associated with amortization of debt discount and issuance costs 382 Total $ 4,910 Certain of our debt instruments require that we comply with a number of restrictive financial covenants. As of March 31, 2024, we were compliant with these financial covenants. Our debt matures on the following schedule (in thousands): Year Ending December 31, March 31, 2024 2024 (1) $ 29,214 2025 23,717 2026 646,300 2027 — 2028 345,000 Thereafter 1,400,000 Total $ 2,444,231 (2) (1) Represents the nine months ending December 31, 2024. (2) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $27.4 million. We capitalized interest costs of $589,000 in the three months ended March 31, 2024 and $770,000 in the three months ended March 31, 2023. The following table sets forth information pertaining to the fair value of our debt (in thousands): March 31, 2024 December 31, 2023 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Fixed-rate debt Unsecured Senior Notes $ 2,118,569 $ 1,880,835 $ 2,117,358 $ 1,876,611 Other fixed-rate debt 66,139 63,013 66,744 63,692 Variable-rate debt 232,165 232,105 232,185 232,270 $ 2,416,873 $ 2,175,953 $ 2,416,287 $ 2,172,573

Interest Rate Derivatives

Interest Rate Derivatives	3 Months Ended
	Mar. 31, 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 March 31, December 31, $ 10,580 (1) 1.678% SOFR + 0.10% 8/1/2019 8/1/2026 $ 639 $ 571 $ 22,400 (2) 0.573% SOFR + 0.10% 4/1/2020 3/26/2025 963 1,084 $ 150,000 3.742% One-Month SOFR 2/1/2023 2/2/2026 2,071 681 $ 50,000 3.747% One-Month SOFR 2/1/2023 2/2/2026 686 222 $ 4,359 $ 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 March 31, December 31, Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 4,359 $ 2,558 The table below presents the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of Income (Loss) Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations Derivatives in Hedging Relationships For the Three Months Ended March 31, For the Three Months Ended March 31, 2024 2023 2024 2023 Interest rate derivatives $ 2,981 $ (215) $ 1,180 $ 591 Based on the fair value of our derivatives as of March 31, 2024, we estimate that approximately $3.6 million 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	3 Months Ended
	Mar. 31, 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 Three Months Ended March 31, 2024 2023 Beginning balance $ 23,580 $ 26,293 Distributions to noncontrolling interests (468) (763) Net income attributable to noncontrolling interests 469 699 Adjustments for changes in fair value of interests (615) (781) Ending balance $ 22,966 $ 25,448

Equity

Equity	3 Months Ended
	Mar. 31, 2024
Equity [Abstract]
Equity	Equity As of March 31, 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 March 31, 2024 and $0.285 in the three months ended March 31, 2023. See Note 15 for disclosure of common share activity pertaining to our share-based compensation plans.

Information by Business Segment

Information by Business Segment	3 Months Ended
	Mar. 31, 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). 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 March 31, 2024 Revenues from real estate operations $ 78,068 $ 21,426 $ 16,411 $ 8,226 $ 16,808 $ 8,457 $ 149,396 $ 17,267 $ 166,663 Property operating expenses (27,890) (9,262) (8,688) (3,626) (5,792) (943) (56,201) (10,545) (66,746) UJV NOI allocable to COPT Defense — — — — — 1,740 1,740 — 1,740 NOI from real estate operations $ 50,178 $ 12,164 $ 7,723 $ 4,600 $ 11,016 $ 9,254 $ 94,935 $ 6,722 $ 101,657 Additions to long-lived assets $ 26,340 $ 4,491 $ — $ 598 $ 672 $ — $ 32,101 $ 4,790 $ 36,891 Transfers from non-operating properties $ 1,575 $ 993 $ 9 $ — $ 32,884 $ 3,075 $ 38,536 $ 9 $ 38,545 Segment assets at March 31, 2024 $ 1,458,458 $ 489,544 $ 187,232 $ 161,210 $ 584,790 $ 434,194 $ 3,315,428 $ 312,784 $ 3,628,212 Three Months Ended March 31, 2023 Revenues from real estate operations $ 69,777 $ 19,829 $ 15,605 $ 7,925 $ 13,414 $ 6,692 $ 133,242 $ 18,439 $ 151,681 Property operating expenses (24,520) (7,572) (7,945) (3,543) (4,636) (594) (48,810) (10,610) (59,420) UJV NOI allocable to COPT Defense — — — — — 1,642 1,642 — 1,642 NOI from real estate operations $ 45,257 $ 12,257 $ 7,660 $ 4,382 $ 8,778 $ 7,740 $ 86,074 $ 7,829 $ 93,903 Additions to long-lived assets $ 12,135 $ 2,398 $ 62 $ 759 $ 6,594 $ — $ 21,948 $ 3,289 $ 25,237 Transfers from non-operating properties $ 5,781 $ 238 $ 28 $ 2,650 $ 14,392 $ 3,311 $ 26,400 $ 13 $ 26,413 Segment assets at March 31, 2023 $ 1,390,273 $ 486,649 $ 193,160 $ 169,235 $ 472,237 $ 324,422 $ 3,035,976 $ 549,138 $ 3,585,114 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 March 31, 2024 2023 Segment revenues from real estate operations $ 166,663 $ 151,681 Construction contract and other service revenues 26,603 15,820 Total revenues $ 193,266 $ 167,501 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 March 31, 2024 2023 UJV NOI allocable to COPT Defense $ 1,740 $ 1,642 Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense (1,671) (1,704) Add: Equity in loss of unconsolidated non-real estate entities — (2) Equity in income (loss) of unconsolidated entities $ 69 $ (64) 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 March 31, 2024 2023 Construction contract and other service revenues $ 26,603 $ 15,820 Construction contract and other service expenses (26,007) (15,201) NOI from service operations $ 596 $ 619 The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to net income as reported on our consolidated statements of operations (in thousands): For the Three Months Ended March 31, 2024 2023 NOI from real estate operations $ 101,657 $ 93,903 NOI from service operations 596 619 Depreciation and other amortization associated with real estate operations (38,351) (36,995) General, administrative, leasing and other expenses (11,747) (10,490) Interest expense (20,767) (16,442) Interest and other income, net 4,122 2,256 Gain on sales of real estate — 49,378 Equity in income (loss) of unconsolidated entities 69 (64) UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities (1,740) (1,642) Income tax expense (168) (125) Net income $ 33,671 $ 80,398 The following table reconciles our segment assets to our consolidated total assets (in thousands): March 31, March 31, Segment assets $ 3,628,212 $ 3,585,114 Operating properties lease liabilities included in segment assets 33,550 35,327 Non-operating property assets 245,828 345,518 Other assets 325,305 212,033 Total consolidated assets $ 4,232,895 $ 4,177,992 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, 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	3 Months Ended
	Mar. 31, 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 March 31, 2024 2023 Construction contract revenue: Guaranteed maximum price $ 13,640 $ 6,743 Firm fixed price 10,900 5,879 Cost-plus fee 1,486 2,709 Other 577 489 $ 26,603 $ 15,820 We recognized an insignificant amount of revenue in the three months ended March 31, 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 Three Months Ended March 31, 2024 2023 Beginning balance $ 10,500 $ 7,618 Ending balance $ 12,734 $ 6,786 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 Three Months Ended March 31, 2024 2023 Beginning balance $ 15,086 $ 22,331 Ending balance $ 25,857 $ 20,619 Contract liabilities are included in other liabilities on our consolidated balance sheets. Changes in contract liabilities were as follows (in thousands): For the Three Months Ended March 31, 2024 2023 Beginning balance $ 4,176 $ 2,867 Ending balance $ 2,783 $ 3,399 Portion of beginning balance recognized in revenue during period $ 1,487 $ 77 Revenue allocated to the remaining performance obligations under existing contracts as of March 31, 2024 that will be recognized as revenue in future periods was $49.3 million, all of which we expect to recognize in the nine months ending December 31, 2024. We have no deferred incremental costs incurred to obtain or fulfill our construction contracts or other service revenues as of March 31, 2024 and December 31, 2023. Credit loss expense or recoveries on construction contracts receivable and unbilled construction revenue were insignificant for the periods reported herein.

Credit Losses on Financial Asse

Credit Losses on Financial Assets and Other Instruments	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2024 and 2023 (in thousands): Investing Receivables Tenant Notes Other Assets (2) Total December 31, 2023 $ 2,377 $ 666 $ 153 $ 3,196 Credit loss expense (recoveries) (3) (16) 116 (78) 22 March 31, 2024 $ 2,361 $ 782 $ 75 $ 3,218 December 31, 2022 $ 2,794 $ 778 $ 268 $ 3,840 Credit loss expense (recoveries) (3) 143 (19) (57) 67 Write-offs — (33) — (33) March 31, 2023 $ 2,937 $ 726 $ 211 $ 3,874 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of March 31, 2024 and December 31, 2023 included $16,000 and $87,000, respectively, in the line entitled “accounts receivable, net” and $59,000 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 March 31, 2024 (in thousands): Origination Year 2019 and Earlier 2020 2021 2022 2023 2024 Total Investing receivables: Credit risk classification: Investment grade $ 65,932 $ 2,529 $ 9,291 $ — $ 265 $ — $ 78,017 Non-investment grade — — — 6,867 — — 6,867 Total $ 65,932 $ 2,529 $ 9,291 $ 6,867 $ 265 $ — $ 84,884 Tenant notes receivable: Credit risk classification: Investment grade $ 658 $ 94 $ — $ — $ — $ — $ 752 Non-investment grade 151 1,400 — — — 487 2,038 Total $ 809 $ 1,494 $ — $ — $ — $ 487 $ 2,790 Sales-type lease receivables: Credit risk classification: Investment grade $ — $ 4,949 $ — $ — $ — $ 1,160 $ 6,109 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 March 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. Tenant notes receivable on nonaccrual status as of March 31, 2024 and December 31, 2023 were not significant. We did not recognize any interest income on tenant notes receivable on nonaccrual status during the three months ended March 31, 2024 and 2023.

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 353,455 $ 25.82 Granted 135,481 $ 24.56 Forfeited (7,131) $ 26.01 Vested (121,702) $ 26.06 Unvested as of March 31, 2024 360,103 $ 25.26 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 $3.0 million for the three months ended March 31, 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 three months ended March 31, 2024: Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 194,415 $ 25.76 Granted 110,203 $ 24.56 Vested (75,485) $ 26.08 Unvested as of March 31, 2024 229,133 $ 25.08 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 $1.8 million for the three months ended March 31, 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.

Earnings Per Share ("EPS")

Earnings Per Share ("EPS")	3 Months Ended
	Mar. 31, 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 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 March 31, 2024 2023 Numerator: Net income attributable to common shareholders $ 32,609 $ 78,779 Income attributable to share-based compensation awards for basic EPS (150) (297) Numerator for basic EPS on net income attributable to common shareholders 32,459 78,482 Redeemable noncontrolling interests — (64) Adjustment to income attributable to share-based compensation awards for diluted EPS 21 49 Numerator for diluted EPS on net income attributable to common shareholders $ 32,480 $ 78,467 Denominator (all weighted averages): Denominator for basic EPS (common shares) 112,231 112,127 Dilutive effect of redeemable noncontrolling interests — 91 Dilutive effect of share-based compensation awards 509 410 Denominator for diluted EPS (common shares) 112,740 112,628 Basic EPS attributable to common shareholders $ 0.29 $ 0.70 Diluted EPS attributable to common shareholders $ 0.29 $ 0.70 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 March 31, 2024 2023 Conversion of common units 1,625 1,489 Conversion of redeemable noncontrolling interests 947 972 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 March 31, 2024 and 2023 of 429,000 and 398,000, respectively; • weighted average TB-PIUs for the three months ended March 31, 2024 and 2023 of 206,000 and 181,000, respectively; and • weighted average vested PIUs for the three months ended March 31, 2024 and 2023 of 188,000 and 103,000, 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 months ended March 31, 2024 was less than the exchange price applicable to that period.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 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 March 31, 2024, management believes that it is reasonably possible that we could recognize a loss of up to $4.6 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 $27 million as of March 31, 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 March 31, 2024, we do not expect any such future fundings will be required.

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Mar. 31, 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)	3 Months Ended
	Mar. 31, 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. We are currently assessing the impact of this guidance on our future related disclosures. 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 are currently assessing the application of this guidance on our future related disclosures.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 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) Marketable securities in deferred compensation plan $ 1,959 $ — $ — $ 1,959 Interest rate derivatives — 4,359 — 4,359 Total assets $ 1,959 $ 4,359 $ — $ 6,318 Liabilities: (2) Deferred compensation plan liability $ — $ 1,959 $ — $ 1,959 (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)	3 Months Ended
	Mar. 31, 2024
Real Estate [Abstract]
Schedule of operating properties, net	Operating properties, net consisted of the following (in thousands): March 31, December 31, Land $ 488,371 $ 482,964 Buildings and improvements 4,218,702 4,164,004 Less: Accumulated depreciation (1,434,621) (1,400,162) Operating properties, net $ 3,272,452 $ 3,246,806
Schedule of allocation of acquisition costs	The table below sets forth the allocation of the purchase price and transaction costs associated with this acquisition (in thousands): Land, operating properties $ 5,428 Building and improvements 2,534 Intangible assets on real estate acquisitions 7,248 Total acquisition cost $ 15,210
Schedule of intangible assets acquired	Intangible assets recorded in connection with this acquisition 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)	3 Months Ended
	Mar. 31, 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 March 31, Lease revenue 2024 2023 Fixed $ 126,198 $ 116,039 Variable 39,235 34,521 $ 165,433 $ 150,560
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 March 31, December 31, Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 40,368 $ 41,296 Finance leases - Property Prepaid expenses and other assets, net 2,547 2,565 Total right-of-use assets $ 42,915 $ 43,861 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 33,141 $ 33,931 Finance leases - Property Other liabilities 409 415 Total lease liabilities $ 33,550 $ 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 March 31, Lease cost 2024 2023 Operating lease cost Property leases - fixed Property operating expenses $ 1,859 $ 1,535 Property leases - variable Property operating expenses 34 17 Finance lease cost Amortization of property right-of-use assets Property operating expenses 19 20 Interest on lease liabilities Interest expense 9 13 $ 1,921 $ 1,585 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Three Months Ended March 31, Supplemental cash flow information 2024 2023 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 1,724 $ 1,185 Operating cash flows for financing leases $ 9 $ 13 Financing cash flows for financing leases $ 6 $ 4
Schedule of payments due on property operating leases	Payments on property leases were due as follows (in thousands): March 31, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 5,099 $ 46 2025 2,403 63 2026 1,815 65 2027 1,830 66 2028 1,847 69 Thereafter 139,906 297 Total lease payments 152,900 606 Less: Amount representing interest (119,759) (197) Lease liability $ 33,141 $ 409 (1) Represents the nine months ending December 31, 2024.
Schedule of payments due on property finance leases	Payments on property leases were due as follows (in thousands): March 31, 2024 Year Ending December 31, Operating Leases Finance Leases 2024 (1) $ 5,099 $ 46 2025 2,403 63 2026 1,815 65 2027 1,830 66 2028 1,847 69 Thereafter 139,906 297 Total lease payments 152,900 606 Less: Amount representing interest (119,759) (197) Lease liability $ 33,141 $ 409 (1) Represents the nine months ending December 31, 2024.

Real Estate Joint Ventures (Tab

Real Estate Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2024 pertaining to our investments in consolidated real estate joint ventures, which are each variable interest entities (dollars in thousands): Nominal Ownership % March 31, 2024 Date Formed Total Encumbered Assets Total Liabilities Mortgage Debt Entity Location LW Redstone Company, LLC (1) 3/23/2010 85% Huntsville, Alabama $ 723,509 $ 98,418 $ 98,619 $ 50,205 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 130,123 — 3,579 — M Square Associates, LLC 6/26/2007 50% College Park, Maryland 98,456 56,944 50,317 48,337 $ 952,088 $ 155,362 $ 152,515 $ 98,542 (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 March 31, December 31, Redshift JV LLC 1/10/2023 10% 3 $ 21,021 $ 21,053 BREIT COPT DC JV LLC 6/20/2019 10% 9 10,321 10,629 Quark JV LLC 12/14/2022 10% 2 6,722 6,727 B RE COPT DC JV III LLC 6/2/2021 10% 2 2,533 2,643 B RE COPT DC JV II LLC (2) 10/30/2020 10% 8 (2,982) (2,777) 24 $ 37,615 $ 38,275 (1) Included $40.6 million and $41.1 million reported in “investment in unconsolidated real estate joint ventures” and $3.0 million and $2.8 million for investments with deficit balances reported in “other liabilities” on our consolidated balance sheets as of March 31, 2024 and December 31, 2023, respectively. (2)

Investing Receivables (Tables)

Investing Receivables (Tables)	3 Months Ended
	Mar. 31, 2024
Receivables [Abstract]
Schedule of investing receivables	Investing receivables consisted of the following (in thousands): March 31, December 31, Notes receivable from the City of Huntsville $ 78,017 $ 77,022 Other investing loan receivable 6,867 6,867 Amortized cost basis 84,884 83,889 Allowance for credit losses (2,361) (2,377) Investing receivables, net $ 82,523 $ 81,512

Debt, Net (Tables)

Debt, Net (Tables)	3 Months Ended
	Mar. 31, 2024
Debt Disclosure [Abstract]
Schedule of debt	Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of March 31, 2024 March 31, December 31, Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed-rate mortgage debt $ 65,753 $ 66,314 3.82% to 4.62% (2) 2024-2026 Variable-rate secured debt 32,789 32,894 SOFR + 0.10% + 1.45% to 1.55% (3) 2025-2026 (4) Total mortgage and other secured debt 98,542 99,208 Revolving Credit Facility 75,000 75,000 SOFR + 0.10% + 0.725% to 1.400% (5) October 2026 (6) Term Loan Facility 124,376 124,291 SOFR + 0.10% + 0.850% to 1.700% (7) January 2026 (8) Unsecured Senior Notes 2.25%, $400,000 aggregate principal 397,879 397,608 2.25% (9) March 2026 5.25%, $345,000 aggregate principal (10) 336,237 335,802 5.25% (11) September 2028 2.00%, $400,000 aggregate principal 397,593 397,471 2.00% (12) January 2029 2.75%, $600,000 aggregate principal 591,489 591,212 2.75% (13) April 2031 2.90%, $400,000 aggregate principal 395,371 395,265 2.90% (14) December 2033 Unsecured note payable 386 430 0% (15) May 2026 Total debt, net $ 2,416,873 $ 2,416,287 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $5.0 million as of March 31, 2024 and $5.3 million as of December 31, 2023. (2) The weighted average interest rate on our fixed-rate mortgage debt was 4.10% as of March 31, 2024. (3) 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 March 31, 2024 was 2.45%; excluding the effect of these swaps, the weighted average interest rate on this debt as of March 31, 2024 was 6.93%. (4) 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. (5) The weighted average interest rate on the Revolving Credit Facility was 6.48% as of March 31, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (6) 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. (7) The interest rate on this loan was 6.73% as of March 31, 2024, excluding the effect of interest rate swaps that hedge the risk of interest rate changes (see Note 9). (8) 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. (9) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.7 million as of March 31, 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%. (10) 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 March 31, 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). (11) The carrying value of these notes reflects unamortized commissions totaling $7.7 million as of March 31, 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%. (12) The carrying value of these notes reflects unamortized discounts and commissions totaling $1.7 million as of March 31, 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%. (13) The carrying value of these notes reflects unamortized discounts and commissions totaling $7.4 million as of March 31, 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%. (14) The carrying value of these notes reflects unamortized discounts and commissions totaling $3.8 million as of March 31, 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%. (15) 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 $25,000 as of March 31, 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 months ended March 31, 2024 (in thousands): Interest expense at stated interest rate $ 4,528 Interest expense associated with amortization of debt discount and issuance costs 382 Total $ 4,910
Schedule of debt maturities	Our debt matures on the following schedule (in thousands): Year Ending December 31, March 31, 2024 2024 (1) $ 29,214 2025 23,717 2026 646,300 2027 — 2028 345,000 Thereafter 1,400,000 Total $ 2,444,231 (2) (1) Represents the nine months ending December 31, 2024. (2) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $27.4 million.
Schedule of fair value of debt	The following table sets forth information pertaining to the fair value of our debt (in thousands): March 31, 2024 December 31, 2023 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Fixed-rate debt Unsecured Senior Notes $ 2,118,569 $ 1,880,835 $ 2,117,358 $ 1,876,611 Other fixed-rate debt 66,139 63,013 66,744 63,692 Variable-rate debt 232,165 232,105 232,185 232,270 $ 2,416,873 $ 2,175,953 $ 2,416,287 $ 2,172,573

Interest Rate Derivatives (Tabl

Interest Rate Derivatives (Tables)	3 Months Ended
	Mar. 31, 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 March 31, December 31, $ 10,580 (1) 1.678% SOFR + 0.10% 8/1/2019 8/1/2026 $ 639 $ 571 $ 22,400 (2) 0.573% SOFR + 0.10% 4/1/2020 3/26/2025 963 1,084 $ 150,000 3.742% One-Month SOFR 2/1/2023 2/2/2026 2,071 681 $ 50,000 3.747% One-Month SOFR 2/1/2023 2/2/2026 686 222 $ 4,359 $ 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 March 31, December 31, Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 4,359 $ 2,558
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 Income (Loss) Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations Derivatives in Hedging Relationships For the Three Months Ended March 31, For the Three Months Ended March 31, 2024 2023 2024 2023 Interest rate derivatives $ 2,981 $ (215) $ 1,180 $ 591

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Tables)	3 Months Ended
	Mar. 31, 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 Three Months Ended March 31, 2024 2023 Beginning balance $ 23,580 $ 26,293 Distributions to noncontrolling interests (468) (763) Net income attributable to noncontrolling interests 469 699 Adjustments for changes in fair value of interests (615) (781) Ending balance $ 22,966 $ 25,448

Information by Business Segme_2

Information by Business Segment (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2024 Revenues from real estate operations $ 78,068 $ 21,426 $ 16,411 $ 8,226 $ 16,808 $ 8,457 $ 149,396 $ 17,267 $ 166,663 Property operating expenses (27,890) (9,262) (8,688) (3,626) (5,792) (943) (56,201) (10,545) (66,746) UJV NOI allocable to COPT Defense — — — — — 1,740 1,740 — 1,740 NOI from real estate operations $ 50,178 $ 12,164 $ 7,723 $ 4,600 $ 11,016 $ 9,254 $ 94,935 $ 6,722 $ 101,657 Additions to long-lived assets $ 26,340 $ 4,491 $ — $ 598 $ 672 $ — $ 32,101 $ 4,790 $ 36,891 Transfers from non-operating properties $ 1,575 $ 993 $ 9 $ — $ 32,884 $ 3,075 $ 38,536 $ 9 $ 38,545 Segment assets at March 31, 2024 $ 1,458,458 $ 489,544 $ 187,232 $ 161,210 $ 584,790 $ 434,194 $ 3,315,428 $ 312,784 $ 3,628,212 Three Months Ended March 31, 2023 Revenues from real estate operations $ 69,777 $ 19,829 $ 15,605 $ 7,925 $ 13,414 $ 6,692 $ 133,242 $ 18,439 $ 151,681 Property operating expenses (24,520) (7,572) (7,945) (3,543) (4,636) (594) (48,810) (10,610) (59,420) UJV NOI allocable to COPT Defense — — — — — 1,642 1,642 — 1,642 NOI from real estate operations $ 45,257 $ 12,257 $ 7,660 $ 4,382 $ 8,778 $ 7,740 $ 86,074 $ 7,829 $ 93,903 Additions to long-lived assets $ 12,135 $ 2,398 $ 62 $ 759 $ 6,594 $ — $ 21,948 $ 3,289 $ 25,237 Transfers from non-operating properties $ 5,781 $ 238 $ 28 $ 2,650 $ 14,392 $ 3,311 $ 26,400 $ 13 $ 26,413 Segment assets at March 31, 2023 $ 1,390,273 $ 486,649 $ 193,160 $ 169,235 $ 472,237 $ 324,422 $ 3,035,976 $ 549,138 $ 3,585,114
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 March 31, 2024 2023 Segment revenues from real estate operations $ 166,663 $ 151,681 Construction contract and other service revenues 26,603 15,820 Total revenues $ 193,266 $ 167,501
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 March 31, 2024 2023 UJV NOI allocable to COPT Defense $ 1,740 $ 1,642 Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense (1,671) (1,704) Add: Equity in loss of unconsolidated non-real estate entities — (2) Equity in income (loss) of unconsolidated entities $ 69 $ (64)
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 March 31, 2024 2023 Construction contract and other service revenues $ 26,603 $ 15,820 Construction contract and other service expenses (26,007) (15,201) NOI from service operations $ 596 $ 619
Schedule of reconciliation of net operating income from real estate operations for reportable segments and service operations to net income	The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to net income as reported on our consolidated statements of operations (in thousands): For the Three Months Ended March 31, 2024 2023 NOI from real estate operations $ 101,657 $ 93,903 NOI from service operations 596 619 Depreciation and other amortization associated with real estate operations (38,351) (36,995) General, administrative, leasing and other expenses (11,747) (10,490) Interest expense (20,767) (16,442) Interest and other income, net 4,122 2,256 Gain on sales of real estate — 49,378 Equity in income (loss) of unconsolidated entities 69 (64) UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities (1,740) (1,642) Income tax expense (168) (125) Net income $ 33,671 $ 80,398
Schedule of reconciliation of segment assets to total assets	The following table reconciles our segment assets to our consolidated total assets (in thousands): March 31, March 31, Segment assets $ 3,628,212 $ 3,585,114 Operating properties lease liabilities included in segment assets 33,550 35,327 Non-operating property assets 245,828 345,518 Other assets 325,305 212,033 Total consolidated assets $ 4,232,895 $ 4,177,992

Construction Contract and Oth_2

Construction Contract and Other Service Revenues (Tables)	3 Months Ended
	Mar. 31, 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 March 31, 2024 2023 Construction contract revenue: Guaranteed maximum price $ 13,640 $ 6,743 Firm fixed price 10,900 5,879 Cost-plus fee 1,486 2,709 Other 577 489 $ 26,603 $ 15,820
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 Three Months Ended March 31, 2024 2023 Beginning balance $ 10,500 $ 7,618 Ending balance $ 12,734 $ 6,786 For the Three Months Ended March 31, 2024 2023 Beginning balance $ 15,086 $ 22,331 Ending balance $ 25,857 $ 20,619 For the Three Months Ended March 31, 2024 2023 Beginning balance $ 4,176 $ 2,867 Ending balance $ 2,783 $ 3,399 Portion of beginning balance recognized in revenue during period $ 1,487 $ 77

Credit Losses on Financial As_2

Credit Losses on Financial Assets and Other Instruments (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2024 and 2023 (in thousands): Investing Receivables Tenant Notes Other Assets (2) Total December 31, 2023 $ 2,377 $ 666 $ 153 $ 3,196 Credit loss expense (recoveries) (3) (16) 116 (78) 22 March 31, 2024 $ 2,361 $ 782 $ 75 $ 3,218 December 31, 2022 $ 2,794 $ 778 $ 268 $ 3,840 Credit loss expense (recoveries) (3) 143 (19) (57) 67 Write-offs — (33) — (33) March 31, 2023 $ 2,937 $ 726 $ 211 $ 3,874 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of March 31, 2024 and December 31, 2023 included $16,000 and $87,000, respectively, in the line entitled “accounts receivable, net” and $59,000 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 March 31, 2024 (in thousands): Origination Year 2019 and Earlier 2020 2021 2022 2023 2024 Total Investing receivables: Credit risk classification: Investment grade $ 65,932 $ 2,529 $ 9,291 $ — $ 265 $ — $ 78,017 Non-investment grade — — — 6,867 — — 6,867 Total $ 65,932 $ 2,529 $ 9,291 $ 6,867 $ 265 $ — $ 84,884 Tenant notes receivable: Credit risk classification: Investment grade $ 658 $ 94 $ — $ — $ — $ — $ 752 Non-investment grade 151 1,400 — — — 487 2,038 Total $ 809 $ 1,494 $ — $ — $ — $ 487 $ 2,790 Sales-type lease receivables: Credit risk classification: Investment grade $ — $ 4,949 $ — $ — $ — $ 1,160 $ 6,109

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 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 three months ended March 31, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 353,455 $ 25.82 Granted 135,481 $ 24.56 Forfeited (7,131) $ 26.01 Vested (121,702) $ 26.06 Unvested as of March 31, 2024 360,103 $ 25.26 The following table summarizes TB-PIUs activity under our share-based compensation plans for the three months ended March 31, 2024: Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2023 194,415 $ 25.76 Granted 110,203 $ 24.56 Vested (75,485) $ 26.08 Unvested as of March 31, 2024 229,133 $ 25.08
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)	3 Months Ended
	Mar. 31, 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 March 31, 2024 2023 Numerator: Net income attributable to common shareholders $ 32,609 $ 78,779 Income attributable to share-based compensation awards for basic EPS (150) (297) Numerator for basic EPS on net income attributable to common shareholders 32,459 78,482 Redeemable noncontrolling interests — (64) Adjustment to income attributable to share-based compensation awards for diluted EPS 21 49 Numerator for diluted EPS on net income attributable to common shareholders $ 32,480 $ 78,467 Denominator (all weighted averages): Denominator for basic EPS (common shares) 112,231 112,127 Dilutive effect of redeemable noncontrolling interests — 91 Dilutive effect of share-based compensation awards 509 410 Denominator for diluted EPS (common shares) 112,740 112,628 Basic EPS attributable to common shareholders $ 0.29 $ 0.70 Diluted EPS attributable to common shareholders $ 0.29 $ 0.70
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 March 31, 2024 2023 Conversion of common units 1,625 1,489 Conversion of redeemable noncontrolling interests 947 972

Organization (Details)

Organization (Details) - 3 months ended Mar. 31, 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	193
Area of real estate property (in sqft or acres) | ft²		22,000
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	163
Area of real estate property (in sqft or acres) | ft²		16,300
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	6
Area of real estate property (in sqft or acres) | ft²		959
Properties under development | Office Properties | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	3
Properties under development | Single-tenant data centers | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	3
Properties under development, partially operational | Defense/IT Portfolio
Investments in real estate
Number of real estate properties	1
Land controlled for development | Defense/IT Portfolio
Investments in real estate
Area of real estate property (in sqft or acres)		7,700	650
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 - Narra

Fair Value Measurements - Narrative (Details) - Fair value measurement on a recurring basis - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2024
Assets and liabilities measured at fair value on a recurring basis
Marketable securities in deferred compensation plan		$ 1,959
Deferred compensation plan | Trustees and Management
Assets and liabilities measured at fair value on a recurring basis
Maximum percentage of participants' compensation which is deferrable (as a percent)	100%
Marketable securities in deferred compensation plan		$ 2,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities, Measured on Recurring Basis (Details) - Fair value measurement on a recurring basis $ in Thousands	Mar. 31, 2024 USD ($)
Assets:
Marketable securities in deferred compensation plan	$ 1,959
Interest rate derivatives	4,359
Total assets	6,318
Liabilities:
Deferred compensation plan liability	1,959
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Marketable securities in deferred compensation plan	1,959
Interest rate derivatives	0
Total assets	1,959
Liabilities:
Deferred compensation plan liability	0
Significant Other Observable Inputs (Level 2)
Assets:
Marketable securities in deferred compensation plan	0
Interest rate derivatives	4,359
Total assets	4,359
Liabilities:
Deferred compensation plan liability	1,959
Significant Unobservable  Inputs (Level 3)
Assets:
Marketable securities in deferred compensation plan	0
Interest rate derivatives	0
Total assets	0
Liabilities:
Deferred compensation plan liability	$ 0

Properties, Net - Operating Pro

Properties, Net - Operating Properties, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Operating Properties, Net
Operating properties, net	$ 3,272,452	$ 3,246,806
Operating Properties
Operating Properties, Net
Less: Accumulated depreciation	(1,434,621)	(1,400,162)
Operating properties, net	3,272,452	3,246,806
Operating Properties | Land
Operating Properties, Net
Gross	488,371	482,964
Operating Properties | Buildings and improvements
Operating Properties, Net
Gross	$ 4,218,702	$ 4,164,004

Properties, Net - Narrative (De

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

Properties, Net - Allocation of

Properties, Net - Allocation of Acquisition Costs (Details) - 6841 Benjamin Franklin Drive $ in Thousands	Mar. 15, 2024 USD ($)
Business Acquisition [Line Items]
Intangible assets on real estate acquisitions	$ 7,248
Total acquisition cost	15,210
Land, operating properties
Business Acquisition [Line Items]
Real estate	5,428
Building and improvements
Business Acquisition [Line Items]
Real estate	$ 2,534

Properties, Net - Intangible as

Properties, Net - Intangible assets Acquired (Details) - 6841 Benjamin Franklin Drive $ in Thousands	Mar. 15, 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
	Mar. 31, 2024	Mar. 31, 2023
Leases [Abstract]
Fixed	$ 126,198	$ 116,039
Variable	39,235	34,521
Lease revenue	$ 165,433	$ 150,560

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	Mar. 31, 2024 USD ($)
Leases [Abstract]
Carrying value of lessee right-of-use asset	$ 42.9
Operating leases, weighted average remaining lease term	51 years
Operating leases, weighted average discount rate	7.32%
Finance leases, weighted average remaining lease term	9 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	Mar. 31, 2024	Dec. 31, 2023
Right-of-use assets
Operating leases - Property	$ 40,368	$ 41,296
Finance leases - Property	2,547	2,565
Total right-of-use assets	$ 42,915	$ 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	$ 33,141	$ 33,931
Finance leases - Property	409	415
Total lease liabilities	$ 33,550	$ 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
	Mar. 31, 2024	Mar. 31, 2023
Operating lease cost
Property leases - fixed	$ 1,859	$ 1,535
Property leases - variable	34	17
Finance lease cost
Amortization of property right-of-use assets	19	20
Interest on lease liabilities	9	13
Lease costs	$ 1,921	$ 1,585

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows for operating leases	$ 1,724	$ 1,185
Operating cash flows for financing leases	9	13
Financing cash flows for financing leases	$ 6	$ 4

Leases - Payments Due on Proper

Leases - Payments Due on Property Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Property Operating Leases
2024	$ 5,099
2025	2,403
2026	1,815
2027	1,830
2028	1,847
Thereafter	139,906
Total lease payments	152,900
Less: Amount representing interest	(119,759)
Lease liability	33,141	$ 33,931
Property Finance Leases
2024	46
2025	63
2026	65
2027	66
2028	69
Thereafter	297
Total lease payments	606
Less: Amount representing interest	(197)
Lease liability	$ 409	$ 415

Real Estate Joint Ventures - In

Real Estate Joint Ventures - Investments in Consolidated Real Estate Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Investments in consolidated real estate joint ventures
Total Assets	$ 4,232,895	$ 4,246,966	$ 4,177,992
Total Liabilities	2,683,883	$ 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	952,088
Total Liabilities	152,515
Variable Interest Entity, Primary Beneficiary | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	155,362
Variable Interest Entity, Primary Beneficiary | Mortgage Debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 98,542
Variable Interest Entity, Primary Beneficiary | LW Redstone Company LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	85%
Total Assets	$ 723,509
Total Liabilities	98,619
Variable Interest Entity, Primary Beneficiary | LW Redstone Company LLC | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	98,418
Variable Interest Entity, Primary Beneficiary | LW Redstone Company LLC | Mortgage Debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 50,205
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC
Investments in consolidated real estate joint ventures
Nominal Ownership %	95%
Total Assets	$ 130,123
Total Liabilities	3,579
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	$ 98,456
Total Liabilities	50,317
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC | Encumbered Assets
Investments in consolidated real estate joint ventures
Total Assets	56,944
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC | Mortgage Debt
Investments in consolidated real estate joint ventures
Total Liabilities	$ 48,337

Real Estate Joint Ventures - _2

Real Estate Joint Ventures - Investments in Unconsolidated Real Estate Joint Ventures (Details) $ in Thousands	Mar. 31, 2024 USD ($) property	Dec. 31, 2023 USD ($)
Schedule of Equity Method Investments [Line Items]
Investment in unconsolidated real estate joint ventures	$ 40,597	$ 41,052
Other liabilities	$ 16,406	18,996
Unconsolidated Real Estate Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of Properties | property	24
Carrying value of Investments	$ 37,615	38,275
Other liabilities	$ 3,000	2,800
Redshift JV LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	3
Carrying value of Investments	$ 21,021	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 Investments	$ 10,321	10,629
Quark JV LLC
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10%
Number of Properties | property	2
Carrying value of Investments	$ 6,722	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 Investments	$ 2,533	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 Investments	$ (2,982)	(2,777)
Difference between the joint venture's cost basis and the entity's share of underlying equity in the net assets	$ 6,800	$ 6,800

Investing Receivables - Investi

Investing Receivables - Investing Receivables (Details) - Investing Receivables - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 84,884	$ 83,889
Allowance for credit losses	(2,361)	(2,377)	$ (2,937)	$ (2,794)
Investing receivables, net	82,523	81,512
Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	78,017	77,022
Other investing loan receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 6,867	$ 6,867

Investing Receivables - Narrati

Investing Receivables - Narrative (Details) - Investing Receivables - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable, net of allowance for credit losses	$ 822	$ 6,000
Notes receivable, fair value disclosure	$ 85,000	$ 84,000
Other investing loan receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	12%
LW Redstone Company LLC | Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	9.95%

Debt, Net - Schedule of Debt (D

Debt, Net - Schedule of Debt (Details)		3 Months Ended
	Mar. 31, 2024 USD ($) extension $ / shares	Mar. 31, 2024 USD ($) extension $ / shares	Dec. 31, 2023 USD ($)
Debt
Carrying Value	$ 2,416,873,000	$ 2,416,873,000	$ 2,416,287,000
Revolving Credit Facility
Debt
Carrying Value	$ 75,000,000	$ 75,000,000	75,000,000
Number of extensions | extension	2	2
Extension option period		6 months
Extension fee percentage		0.0625%
Revolving Credit Facility | Secured Overnight Financing Rate
Debt
Variable rate, additional spread		0.10%
Weighted average interest rate	6.48%	6.48%
Revolving Credit Facility | Minimum | Secured Overnight Financing Rate
Debt
Variable rate, spread		0.725%
Revolving Credit Facility | Maximum | Secured Overnight Financing Rate
Debt
Variable rate, spread		1.40%
Term Loan Facility
Debt
Carrying Value	$ 124,376,000	$ 124,376,000	124,291,000
Number of extensions | extension	2	2
Extension option period		12 months
Extension fee percentage		0.125%
Term Loan Facility | Secured Overnight Financing Rate
Debt
Interest rate	6.73%	6.73%
Variable rate, additional spread		0.10%
Term Loan Facility | Minimum | Secured Overnight Financing Rate
Debt
Variable rate, spread		0.85%
Term Loan Facility | Maximum | Secured Overnight Financing Rate
Debt
Variable rate, spread		1.70%
Mortgage and other secured debt
Debt
Carrying Value	$ 98,542,000	$ 98,542,000	99,208,000
Loans payable
Debt
Net deferred financing costs	5,000,000	5,000,000	5,300,000
Fixed-rate mortgage debt | Mortgage and other secured debt
Debt
Carrying Value	$ 65,753,000	$ 65,753,000	66,314,000
Weighted average interest rate	4.10%	4.10%
Fixed-rate mortgage debt | Mortgage and other secured debt | Minimum
Debt
Interest rate	3.82%	3.82%
Fixed-rate mortgage debt | Mortgage and other secured debt | Maximum
Debt
Interest rate	4.62%	4.62%
Variable-rate secured debt | Mortgage and other secured debt
Debt
Carrying Value	$ 32,789,000	$ 32,789,000	32,894,000
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 | Secured Overnight Financing Rate
Debt
Variable rate, additional spread		0.10%
Weighted average interest rate	6.93%	6.93%
Variable-rate secured debt | Mortgage and other secured debt | Secured Overnight Financing Rate | Interest rate swaps
Debt
Weighted average interest rate	2.45%	2.45%
Variable-rate secured debt | Mortgage and other secured debt | Minimum | Secured Overnight Financing Rate
Debt
Variable rate, spread		1.45%
Variable-rate secured debt | Mortgage and other secured debt | Maximum | Secured Overnight Financing Rate
Debt
Variable rate, spread		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	397,879,000	397,879,000	397,608,000
Unamortized discounts and/or commissions included in carrying value	$ 1,700,000	$ 1,700,000	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	336,237,000	336,237,000	335,802,000
Unamortized discounts and/or commissions included in carrying value	$ 7,700,000	$ 7,700,000	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	397,593,000	397,593,000	397,471,000
Unamortized discounts and/or commissions included in carrying value	$ 1,700,000	$ 1,700,000	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	591,489,000	591,489,000	591,212,000
Unamortized discounts and/or commissions included in carrying value	$ 7,400,000	$ 7,400,000	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	395,371,000	395,371,000	395,265,000
Unamortized discounts and/or commissions included in carrying value	$ 3,800,000	$ 3,800,000	3,900,000
Effective interest rate on debt	3.01%	3.01%
Unsecured note payable
Debt
Interest rate	0%	0%
Carrying Value	$ 386,000	$ 386,000	430,000
Unamortized discounts and/or commissions included in carrying value	$ 25,000	$ 25,000	$ 32,000

Debt, Net - Narrative (Details)

Debt, Net - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Debt
Interest costs capitalized	$ 589	$ 770
5.25%, $345,000 aggregate principal | Unsecured Senior Notes
Debt
Interest rate	5.25%

Debt, Net - Schedule of Interes

Debt, Net - Schedule of Interest Expense (Details) - 5.25%, $345,000 aggregate principal $ in Thousands	3 Months Ended
	Mar. 31, 2024 USD ($)
Debt
Interest expense at stated interest rate	$ 4,528
Interest expense associated with amortization of debt discount and issuance costs	382
Total	$ 4,910

Debt, Net - Debt Maturities (De

Debt, Net - Debt Maturities (Details) $ in Thousands	Mar. 31, 2024 USD ($)
Schedule on basis of which debt matures
2024	$ 29,214
2025	23,717
2026	646,300
2027	0
2028	345,000
Thereafter	1,400,000
Total	2,444,231
Net discounts and deferred financing costs	$ 27,400

Debt, Net - Fair Value of Debt

Debt, Net - Fair Value of Debt (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Carrying Amount
Carrying amount and estimated fair value of debt
Long-term debt	$ 2,416,873	$ 2,416,287
Carrying Amount | Unsecured Senior Notes
Carrying amount and estimated fair value of debt
Long-term debt	2,118,569	2,117,358
Carrying Amount | Other fixed-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	66,139	66,744
Carrying Amount | Variable-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	232,165	232,185
Estimated Fair Value
Carrying amount and estimated fair value of debt
Long-term debt	2,175,953	2,172,573
Estimated Fair Value | Unsecured Senior Notes
Carrying amount and estimated fair value of debt
Long-term debt	1,880,835	1,876,611
Estimated Fair Value | Other fixed-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	63,013	63,692
Estimated Fair Value | Variable-rate debt
Carrying amount and estimated fair value of debt
Long-term debt	$ 232,105	$ 232,270

Interest Rate Derivatives - Key

Interest Rate Derivatives - Key Terms and Fair Value of Interest Rate Derivative (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Fair values of interest rate swap derivatives
Fair value of interest rate swaps	$ 4,359	$ 2,558
Designated | Interest rate swap, effective August 1, 2019
Fair values of interest rate swap derivatives
Notional Amount	$ 10,580
Fixed Rate	1.678%
Fair value of interest rate swaps	$ 639	$ 571
Notional amount of interest rate derivatives after scheduled amortization	10,000
Designated | Interest rate swap, effective August 1, 2019 | Secured Overnight Financing Rate
Fair values of interest rate swap derivatives
Floating Rate Index		0.10%
Designated | Interest rate swap, effective April 1, 2020
Fair values of interest rate swap derivatives
Notional Amount	$ 22,400
Fixed Rate	0.573%
Fair value of interest rate swaps	$ 963	$ 1,084
Notional amount of interest rate derivatives after scheduled amortization	22,100
Designated | Interest rate swap, effective April 1, 2020 | Secured Overnight Financing Rate
Fair values of interest rate swap derivatives
Floating Rate Index		0.10%
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	$ 2,071	$ 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	$ 686	$ 222

Interest Rate Derivatives - Fai

Interest Rate Derivatives - Fair Value and Classification of Interest Rate Derivatives (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Prepaid expenses and other assets, net | Interest rate swaps
Fair value of interest rate derivatives and balance sheet classification
Interest rate swaps designated as cash flow hedges	$ 4,359	$ 2,558

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
	Mar. 31, 2024	Mar. 31, 2023
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of Income (Loss) Recognized in AOCI on Derivatives	$ 2,981	$ (215)
Amount of Income Reclassified from AOCI into Interest Expense on Statement of Operations	1,180	591
Interest rate swaps
Effect of interest rate derivatives on consolidated statements of operations and comprehensive income
Amount of Income (Loss) Recognized in AOCI on Derivatives	2,981	(215)
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	$ 1,180	$ 591

Interest Rate Derivatives - Nar

Interest Rate Derivatives - Narrative (Details) $ in Millions	Mar. 31, 2024 USD ($)
Interest rate swaps | Designated
Fair values of interest rate swap derivatives
Approximate amount to be reclassified from AOCL to interest expense over the next 12 months	$ 3.6

Redeemable Noncontrolling Int_3

Redeemable Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Redeemable Noncontrolling Interest [Roll Forward]
Beginning balance	$ 23,580	$ 26,293
Distributions to noncontrolling interests	(468)	(763)
Net income attributable to noncontrolling interests	469	699
Adjustments for changes in fair value of interests	(615)	(781)
Ending balance	$ 22,966	$ 25,448

Equity (Details)

Equity (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Equity [Abstract]
At the market, offering program established, aggregate value	$ 300
Dividends declared per share (in dollars per share)	$ 0.295	$ 0.285

Information by Business Segme_3

Information by Business Segment - Segment Financial Information for Our Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Segment financial information for real estate operations
Revenues from real estate operations	$ 193,266	$ 167,501
UJV NOI allocable to COPT Defense	1,740	1,642
Segment assets	4,232,895	4,177,992	$ 4,246,966
Segment assets
Segment financial information for real estate operations
Segment assets	3,628,212	3,585,114
Real Estate Operations
Segment financial information for real estate operations
Revenues from real estate operations	166,663	151,681
Property operating expenses	(66,746)	(59,420)
UJV NOI allocable to COPT Defense	1,740	1,642
NOI from real estate operations	101,657	93,903
Additions to long-lived assets	36,891	25,237
Transfers from non-operating properties	38,545	26,413
Real Estate Operations | Defense/IT Portfolio
Segment financial information for real estate operations
Revenues from real estate operations	149,396	133,242
Property operating expenses	(56,201)	(48,810)
UJV NOI allocable to COPT Defense	1,740	1,642
NOI from real estate operations	94,935	86,074
Additions to long-lived assets	32,101	21,948
Transfers from non-operating properties	38,536	26,400
Real Estate Operations | Defense/IT Portfolio | Fort Meade/BW Corridor
Segment financial information for real estate operations
Revenues from real estate operations	78,068	69,777
Property operating expenses	(27,890)	(24,520)
UJV NOI allocable to COPT Defense	0	0
NOI from real estate operations	50,178	45,257
Additions to long-lived assets	26,340	12,135
Transfers from non-operating properties	1,575	5,781
Real Estate Operations | Defense/IT Portfolio | NoVA Defense/IT
Segment financial information for real estate operations
Revenues from real estate operations	21,426	19,829
Property operating expenses	(9,262)	(7,572)
UJV NOI allocable to COPT Defense	0	0
NOI from real estate operations	12,164	12,257
Additions to long-lived assets	4,491	2,398
Transfers from non-operating properties	993	238
Real Estate Operations | Defense/IT Portfolio | Lackland Air Force Base
Segment financial information for real estate operations
Revenues from real estate operations	16,411	15,605
Property operating expenses	(8,688)	(7,945)
UJV NOI allocable to COPT Defense	0	0
NOI from real estate operations	7,723	7,660
Additions to long-lived assets	0	62
Transfers from non-operating properties	9	28
Real Estate Operations | Defense/IT Portfolio | Navy Support
Segment financial information for real estate operations
Revenues from real estate operations	8,226	7,925
Property operating expenses	(3,626)	(3,543)
UJV NOI allocable to COPT Defense	0	0
NOI from real estate operations	4,600	4,382
Additions to long-lived assets	598	759
Transfers from non-operating properties	0	2,650
Real Estate Operations | Defense/IT Portfolio | Redstone Arsenal
Segment financial information for real estate operations
Revenues from real estate operations	16,808	13,414
Property operating expenses	(5,792)	(4,636)
UJV NOI allocable to COPT Defense	0	0
NOI from real estate operations	11,016	8,778
Additions to long-lived assets	672	6,594
Transfers from non-operating properties	32,884	14,392
Real Estate Operations | Defense/IT Portfolio | Data Center Shells
Segment financial information for real estate operations
Revenues from real estate operations	8,457	6,692
Property operating expenses	(943)	(594)
UJV NOI allocable to COPT Defense	1,740	1,642
NOI from real estate operations	9,254	7,740
Additions to long-lived assets	0	0
Transfers from non-operating properties	3,075	3,311
Real Estate Operations | Other
Segment financial information for real estate operations
Revenues from real estate operations	17,267	18,439
Property operating expenses	(10,545)	(10,610)
UJV NOI allocable to COPT Defense	0	0
NOI from real estate operations	6,722	7,829
Additions to long-lived assets	4,790	3,289
Transfers from non-operating properties	9	13
Real Estate Operations | Segment assets
Segment financial information for real estate operations
Segment assets	3,628,212	3,585,114
Real Estate Operations | Segment assets | Defense/IT Portfolio
Segment financial information for real estate operations
Segment assets	3,315,428	3,035,976
Real Estate Operations | Segment assets | Defense/IT Portfolio | Fort Meade/BW Corridor
Segment financial information for real estate operations
Segment assets	1,458,458	1,390,273
Real Estate Operations | Segment assets | Defense/IT Portfolio | NoVA Defense/IT
Segment financial information for real estate operations
Segment assets	489,544	486,649
Real Estate Operations | Segment assets | Defense/IT Portfolio | Lackland Air Force Base
Segment financial information for real estate operations
Segment assets	187,232	193,160
Real Estate Operations | Segment assets | Defense/IT Portfolio | Navy Support
Segment financial information for real estate operations
Segment assets	161,210	169,235
Real Estate Operations | Segment assets | Defense/IT Portfolio | Redstone Arsenal
Segment financial information for real estate operations
Segment assets	584,790	472,237
Real Estate Operations | Segment assets | Defense/IT Portfolio | Data Center Shells
Segment financial information for real estate operations
Segment assets	434,194	324,422
Real Estate Operations | Segment assets | Other
Segment financial information for real estate operations
Segment assets	$ 312,784	$ 549,138

Information by Business Segme_4

Information by Business Segment - Reconciliation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconciliation of segment revenues to total revenues
Construction contract and other service revenues	$ 26,603	$ 15,820
Total revenues	193,266	167,501
Real Estate Operations
Reconciliation of segment revenues to total revenues
Total revenues	$ 166,663	$ 151,681

Information by Business Segme_5

Information by Business Segment - Reconciliation of UJV NOI to Equity in Income (Loss) of Unconsolidated Entities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Reconciliation of UJV NOI allocable to COPT to equity income (loss) in unconsolidated entities
UJV NOI allocable to COPT Defense	$ 1,740	$ 1,642
Less: Income from UJV allocable to COPT Defense attributable to depreciation and amortization expense and interest expense	(1,671)	(1,704)
Add: Equity in loss of unconsolidated non-real estate entities	0	(2)
Equity in income (loss) of unconsolidated entities	$ 69	$ (64)

Information by Business Segme_6

Information by Business Segment - Computation of NOI from Service Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment financial information for real estate operations
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 March 31, 2024 2023 Construction contract and other service revenues $ 26,603 $ 15,820 Construction contract and other service expenses (26,007) (15,201) NOI from service operations $ 596 $ 619
Construction contract and other service revenues	$ 26,603	$ 15,820
Construction contract and other service expenses	(26,007)	(15,201)
Service Operations
Segment financial information for real estate operations
NOI from service operations	$ 596	$ 619

Information by Business Segme_7

Information by Business Segment - Reconciliation of NOI from Real Estate Operations and NOI from Service Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Segment financial information for real estate operations
Depreciation and other amortization associated with real estate operations	$ (38,351)	$ (36,995)
General, administrative, leasing and other expenses	(11,747)	(10,490)
Interest expense	(20,767)	(16,442)
Interest and other income, net	4,122	2,256
Gain on sales of real estate	0	49,378
Equity in income (loss) of unconsolidated entities	69	(64)
UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities	(1,740)	(1,642)
Income tax expense	(168)	(125)
Net income	33,671	80,398
Real Estate Operations
Segment financial information for real estate operations
NOI from real estate operations	101,657	93,903
UJV NOI allocable to COPT Defense included in equity in income (loss) of unconsolidated entities	(1,740)	(1,642)
Service Operations
Segment financial information for real estate operations
NOI from service operations	$ 596	$ 619

Information by Business Segme_8

Information by Business Segment - Reconciliation of Segment Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023
Reconciliation of segment assets to total assets
Total consolidated assets	$ 4,232,895	$ 4,246,966	$ 4,177,992
Operating properties lease liabilities included in segment assets	33,550	$ 34,346
Segment assets
Reconciliation of segment assets to total assets
Total consolidated assets	3,628,212		3,585,114
Operating properties lease liabilities included in segment assets	33,550		35,327
Non-operating property assets
Reconciliation of segment assets to total assets
Total consolidated assets	245,828		345,518
Other assets
Reconciliation of segment assets to total assets
Total consolidated assets	$ 325,305		$ 212,033

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
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 26,603	$ 15,820
Guaranteed maximum price
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	13,640	6,743
Firm fixed price
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	10,900	5,879
Cost-plus fee
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	1,486	2,709
Other
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 577	$ 489

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
	Mar. 31, 2024	Mar. 31, 2023
Change in Accounts Receivable
Beginning balance	$ 48,946
Ending balance	50,088
Construction Contract Revenue
Change in Accounts Receivable
Beginning balance	10,500	$ 7,618
Ending balance	12,734	6,786
Change in Contract with Customer, Asset
Beginning balance	15,086	22,331
Ending balance	25,857	20,619
Change in Contract with Customer, Liability
Beginning balance	4,176	2,867
Ending balance	2,783	3,399
Portion of beginning balance recognized in revenue during period	$ 1,487	$ 77

Construction Contract and Oth_5

Construction Contract and Other Service Revenues - Narrative (Details) - Construction Contract Revenue - USD ($)	Mar. 31, 2024	Dec. 31, 2023
Disaggregation of Revenue [Line Items]
Remaining performance obligations	$ 49,300,000
Deferred incremental costs	$ 0	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	9 months

Credit Losses on Financial As_3

Credit Losses on Financial Assets and Other Instruments - Allowance for Credit Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Beginning balance	$ 3,196	$ 3,840
Credit loss expense (recoveries)	22	67
Write-offs		(33)
Ending balance	3,218	3,874
Other Assets
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	153	268
Credit loss expense (recoveries)	(78)	(57)
Write-offs		0
Ending balance	75	211
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	75	211
Other Assets | Accounts Receivable, Net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	87
Ending balance	16
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	16
Other Assets | Prepaid expenses and other assets, net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	66
Ending balance	59
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	59
Investing Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,377	2,794
Credit loss expense (recoveries)	(16)	143
Write-offs		0
Ending balance	2,361	2,937
Tenant Notes Receivable
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	666	778
Credit loss expense (recoveries)	116	(19)
Write-offs		(33)
Ending balance	$ 782	$ 726

Credit Losses on Financial As_4

Credit Losses on Financial Assets and Other Instruments - Credit Risk Classification (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Investing Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	$ 65,932
2020	2,529
2021	9,291
2022	6,867
2023	265
2024	0
Total	84,884	$ 83,889
Investing Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	65,932
2020	2,529
2021	9,291
2022	0
2023	265
2024	0
Total	78,017
Investing Receivables | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	0
2020	0
2021	0
2022	6,867
2023	0
2024	0
Total	6,867
Tenant notes receivable:
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	809
2020	1,494
2021	0
2022	0
2023	0
2024	487
Total	2,790
Tenant notes receivable: | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	658
2020	94
2021	0
2022	0
2023	0
2024	0
Total	752
Tenant notes receivable: | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	151
2020	1,400
2021	0
2022	0
2023	0
2024	487
Total	2,038
Sales-type lease receivables: | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2019 and Earlier	0
2020	4,949
2021	0
2022	0
2023	0
2024	1,160
Total	$ 6,109

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Shares and TB-PIUs Activity (Details)	3 Months Ended
	Mar. 31, 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	135,481
Forfeited (in shares or units) | shares	(7,131)
Vested (in shares or units) | shares	(121,702)
Unvested at the end of the period (in shares or units) | shares	360,103
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	24.56
Forfeited (in dollars per share or unit) | $ / shares	26.01
Vested (in dollars per share or unit) | $ / shares	26.06
Unvested at the end of the period (in dollars per share or unit) | $ / shares	$ 25.26
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	110,203
Vested (in shares or units) | shares	(75,485)
Unvested at the end of the period (in shares or units) | shares	229,133
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	24.56
Vested (in dollars per share or unit) | $ / shares	26.08
Unvested at the end of the period (in dollars per share or unit) | $ / shares	$ 25.08

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) $ / shares in Units, $ in Millions			3 Months Ended
	Feb. 01, 2024 shares	Jan. 01, 2024 USD ($) percentile_rank $ / shares shares	Mar. 31, 2024 USD ($) form $ / shares shares
Restricted shares
Share-Based Compensation
Aggregate intrinsic value of awards upon vesting | $			$ 3
Granted (in shares or units) | shares			135,481
Granted (in dollars per share or unit) | $ / shares			$ 24.56
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 | $			$ 1.8
Granted (in shares or units) | shares			110,203
Granted (in dollars per share or unit) | $ / shares			$ 24.56
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 | $		$ 5.4
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

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
	Mar. 31, 2024	Mar. 31, 2023
Numerator:
Net income attributable to common shareholders	$ 32,609	$ 78,779
Income attributable to share-based compensation awards for basic EPS	(150)	(297)
Numerator for basic EPS on net income attributable to common shareholders	32,459	78,482
Redeemable noncontrolling interests	0	(64)
Adjustment to income attributable to share-based compensation awards for diluted EPS	21	49
Numerator for diluted EPS on net (loss) income attributable to common shareholders	$ 32,480	$ 78,467
Denominator (all weighted averages):
Denominator for basic EPS (common shares) (in shares)	112,231	112,127
Dilutive effect of redeemable noncontrolling interests (in shares)	0	91
Dilutive effect of share-based compensation awards (in shares)	509	410
Denominator for diluted EPS (common shares) (in shares)	112,740	112,628
Basic EPS attributable to common shareholders (in dollars per share)	$ 0.29	$ 0.70
Diluted EPS attributable to common shareholders (in dollars per share)	$ 0.29	$ 0.70

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
	Mar. 31, 2024	Mar. 31, 2023
Conversion of common units
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	1,625	1,489
Conversion of redeemable noncontrolling interests
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	947	972

Earnings Per Share ("EPS") - Na

Earnings Per Share ("EPS") - Narrative (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Weighted average restricted shares and deferred shares
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	429	398
Weighted average TB-PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	206	181
Weighted Average Vested PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	188	103

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Mar. 31, 2024 USD ($) property
Commitments and Contingencies
Estimate of possible loss (up to)	$ 4.6
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	$ 27