COPT Defense Properties (CDP) 10-K 22 Feb 22 2021 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2021	Feb. 07, 2022	Jun. 30, 2021
Cover [Abstract]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-14023
Entity Registrant Name	CORPORATE OFFICE PROPERTIES TRUST
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	23-2947217
Entity Address, Address Line One	6711 Columbia Gateway Drive
Entity Address, Address Line Two	Suite 300
Entity Address, City or Town	Columbia
Entity Address, State or Province	MD
Entity Address, Postal Zip Code	21046
City Area Code	443
Local Phone Number	285-5400
Title of 12(b) Security	Common Shares of beneficial interest, $0.01 par value
Trading Symbol	OFC
Security Exchange Name	NYSE
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 2.8
Entity Common Stock, Shares Outstanding		112,319,982
Documents Incorporated by Reference	Portions of the proxy statement of Corporate Office Properties Trust for its 2022 Annual Meeting of Shareholders to be filed within 120 days after the end of the fiscal year covered by this Form 10-K are incorporated by reference into Part III of this Form 10-K.
Entity Central Index Key	0000860546
Amendment Flag	false
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Baltimore, Maryland
Auditor Firm ID	238

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Properties, net:
Operating properties, net	$ 3,090,510	$ 2,915,016
Projects in development or held for future development	442,434	447,269
Total properties, net	3,532,944	3,362,285
Property - operating right-of-use assets	38,361	40,570
Property - finance right-of-use assets	2,238	40,425
Assets held for sale, net	192,699	201,820
Cash and cash equivalents	13,262	18,369
Investment in unconsolidated real estate joint ventures	39,889	29,303
Accounts receivable, net	40,752	41,637
Deferred rent receivable	108,926	91,851
Intangible assets on property acquisitions, net	14,567	19,249
Deferred leasing costs (net of accumulated amortization of $31,768 and $30,124, respectively)	65,850	58,177
Prepaid expenses and other assets, net	130,738	104,583
Total assets	4,262,452	4,077,023
Liabilities:
Debt, net	2,272,304	2,086,918
Accounts payable and accrued expenses	186,202	142,717
Rents received in advance and security deposits	32,262	33,425
Dividends and distributions payable	31,299	31,231
Deferred revenue associated with operating leases	9,341	10,832
Property - operating lease liabilities	29,342	30,746
Interest rate derivatives	3,644	9,522
Other liabilities	14,085	12,490
Total liabilities	2,578,479	2,357,881
Commitments and contingencies (Note 19)
Redeemable noncontrolling interests	26,898	25,430
Corporate Office Properties Trust’s shareholders’ equity:
Common Shares of beneficial interest ($0.01 par value; 150,000,000 shares authorized; shares issued and outstanding of 112,327,533 at December 31, 2021 and 112,181,759 at December 31, 2020)	1,123	1,122
Additional paid-in capital	2,481,539	2,478,906
Cumulative distributions in excess of net income	(856,863)	(809,836)
Accumulated other comprehensive loss	(3,059)	(9,157)
Total Corporate Office Properties Trust’s shareholders’ equity	1,622,740	1,661,035
Noncontrolling interests in subsidiaries:
Common units in Corporate Office Properties, L.P. (“COPLP”)	21,363	20,465
Other consolidated entities	12,972	12,212
Noncontrolling interests in subsidiaries	34,335	32,677
Total equity	1,657,075	1,693,712
Total liabilities, redeemable noncontrolling interests and equity	4,262,452	4,077,023
Investing Receivables
Properties, net:
Investing receivables (net of allowance for credit losses of $1,599 and $2,851, respectively)	$ 82,226	$ 68,754

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Accumulated amortization of deferred leasing costs	$ 31,768	$ 30,124
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)	112,327,533	112,181,759
Common Shares of beneficial interest, shares outstanding (in shares)	112,327,533	112,181,759
Investing Receivables
Investing receivable allowance for credit loss	$ 1,599	$ 2,851

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues
Lease revenue		$ 553,668	$ 509,114	$ 493,165
Other property revenue		2,902	2,600	4,893
Construction contract and other service revenues		107,876	70,640	113,763
Total revenues		664,446	582,354	611,821
Operating expenses
Property operating expenses		213,377	190,796	185,449
Depreciation and amortization associated with real estate operations		137,543	126,503	125,008
Construction contract and other service expenses		104,053	67,615	109,962
Impairment losses		0	1,530	329
General, administrative and leasing expenses		36,127	33,001	35,402
Business development expenses and land carry costs		4,647	4,473	4,239
Total operating expenses		495,747	423,918	460,389
Interest expense		(65,398)	(67,937)	(71,052)
Interest and other income		7,879	8,574	7,894
Credit loss recoveries		1,128	933	0
Gain on sales of real estate		65,590	30,209	105,230
Gain on sale of investment in unconsolidated real estate joint venture		0	29,416	0
Loss on early extinguishment of debt		(100,626)	(7,306)	0
Loss on interest rate derivatives		0	(53,196)	0
Income from continuing operations before equity in income of unconsolidated entities and income taxes		77,272	99,129	193,504
Equity in income of unconsolidated entities		1,093	1,825	1,633
Income tax (expense) benefit		(145)	(353)	217
Income from continuing operations		78,220	100,601	195,354
Discontinued operations		3,358	2,277	4,650
Net income		81,578	102,878	200,004
Net income attributable to noncontrolling interests:
Common units in COPLP		(1,012)	(1,180)	(2,363)
Preferred units in COPLP		0	(300)	(564)
Other consolidated entities		(4,025)	(4,024)	(5,385)
Net income attributable to COPT common shareholders		$ 76,541	$ 97,374	$ 191,692
Basic Earnings per common share:
Income from continuing operations - basic (in dollars per share)	[1]	$ 0.65	$ 0.85	$ 1.68
Discontinued operations - basic (in dollars per share)	[1]	0.03	0.02	0.04
Net income attributable to COPT common shareholders - basic (in dollars per share)	[1]	0.68	0.87	1.72
Diluted Earnings per common share:
Income from continuing operations - diluted (in dollars per share)	[1]	0.65	0.85	1.67
Discontinued operations - diluted (in dollar per share)	[1]	0.03	0.02	0.04
Net income attributable to COPT common shareholders - diluted (in dollars per share)	[1]	$ 0.68	$ 0.87	$ 1.71
[1]	Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 81,578	$ 102,878	$ 200,004
Other comprehensive income (loss)
Unrealized income (loss) on interest rate derivatives	1,379	(39,454)	(24,321)
Reclassification adjustments on interest rate derivatives recognized in interest expense	5,048	3,725	(1,415)
Reclassification adjustments on interest rate derivatives recognized in loss on interest rate derivatives	0	51,865	0
Equity in other comprehensive income of equity method investee	0	0	199
Total other comprehensive income (loss)	6,427	16,136	(25,537)
Comprehensive income	88,005	119,014	174,467
Comprehensive income attributable to noncontrolling interests	(5,366)	(5,353)	(7,981)
Comprehensive income attributable to COPT	$ 82,639	$ 113,661	$ 166,486

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock At-the-Market Program	Forward Equity Sale Agreement	Common Shares	Common SharesCumulative Effect, Period of Adoption, Adjusted Balance	Common SharesForward Equity Sale Agreement	Additional Paid-in Capital	Additional Paid-in CapitalCumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-in CapitalCommon Stock At-the-Market Program	Additional Paid-in CapitalForward Equity Sale Agreement	Cumulative Distributions in Excess of Net Income	Cumulative Distributions in Excess of Net IncomeCumulative Effect, Period of Adoption, Adjustment	Cumulative Distributions in Excess of Net IncomeCumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive LossCumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive LossCumulative Effect, Period of Adoption, Adjusted Balance	Noncontrolling Interests	Noncontrolling InterestsCumulative Effect, Period of Adoption, Adjustment	Noncontrolling InterestsCumulative Effect, Period of Adoption, Adjusted Balance
Balance at Dec. 31, 2018	$ 1,627,048					$ 1,102			$ 2,431,355				$ (846,808)			$ (238)			$ 41,637
Balance (in shares) at Dec. 31, 2018	110,241,868
Increase (Decrease) in Shareholders' Equity
Conversion of common units to common shares	$ 0					1			1,585										(1,586)
Redemption of common units	$ (25)																		(25)
Common shares issued during the period (in shares)				1,000	1,614,087
Common shares issued during the period				$ 29	$ 46,454			$ 16			$ 29	$ 46,438
Share-based compensation issuance, net of redemptions (in shares)	106,711
Share-based compensation issuance, net of redemptions	$ 7,456					2			6,131										1,323
Redemption of vested equity awards	(2,064)								(2,064)
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP	0								(167)										167
Comprehensive income	170,632												191,692			(25,206)			4,146
Dividends	(123,159)												(123,159)
Distributions to owners of common and preferred units in COPLP	(2,057)																		(2,057)
Contributions from noncontrolling interests in other consolidated entities	2,570																		2,570
Distributions to noncontrolling interests in other consolidated entities	(5,890)																		(5,890)
Adjustment to arrive at fair value of redeemable noncontrolling interests	$ (1,749)								(1,749)
Balance (in shares) at Dec. 31, 2019	112,068,705
Balance at Dec. 31, 2019	$ 1,719,245	$ (5,541)	$ 1,713,704			1,121	$ 1,121		2,481,558	$ 2,481,558			(778,275)	$ (5,541)	$ (783,816)	(25,444)	$ 0	$ (25,444)	40,285	$ 0	$ 40,285
Increase (Decrease) in Shareholders' Equity
Accounting Standards Update [Extensible List]	Accounting Standards Update 2016-13
Conversion of common units to common shares	$ 0					0			211										(211)
Redemption of preferred units	$ (8,800)																		(8,800)
Share-based compensation issuance, net of redemptions (in shares)	99,045
Share-based compensation issuance, net of redemptions	$ 6,584					1			4,676										1,907
Redemption of vested equity awards	(1,699)								(1,699)
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP	0								767										(767)
Comprehensive income	115,588												97,374			16,287			1,927
Dividends	(123,394)												(123,394)
Distributions to owners of common and preferred units in COPLP	(1,746)																		(1,746)
Contributions from noncontrolling interests in other consolidated entities	112																		112
Distributions to noncontrolling interests in other consolidated entities	(30)																		(30)
Adjustment to arrive at fair value of redeemable noncontrolling interests	$ (6,607)								(6,607)
Balance (in shares) at Dec. 31, 2020	112,181,759
Balance at Dec. 31, 2020	$ 1,693,712					1,122			2,478,906				(809,836)			(9,157)			32,677
Increase (Decrease) in Shareholders' Equity
Conversion of common units to common shares	0								121										(121)
Redemption of common units	$ (339)																		(339)
Share-based compensation issuance, net of redemptions (in shares)	137,720
Share-based compensation issuance, net of redemptions	$ 8,481					1			4,301										4,179
Redemption of vested equity awards	(2,492)								(2,492)
Adjustments to noncontrolling interests resulting from changes in ownership of COPLP	0								2,318										(2,318)
Comprehensive income	84,845												76,541			6,098			2,206
Dividends	(123,568)												(123,568)
Distributions to owners of common and preferred units in COPLP	(1,595)																		(1,595)
Distributions to noncontrolling interests in other consolidated entities	(30)																		(30)
Adjustment to arrive at fair value of redeemable noncontrolling interests	(1,615)								(1,615)
Other	$ (324)																		(324)
Balance (in shares) at Dec. 31, 2021	112,327,533
Balance at Dec. 31, 2021	$ 1,657,075					$ 1,123			$ 2,481,539				$ (856,863)			$ (3,059)			$ 34,335

Consolidated Statements of Eq_2

Consolidated Statements of Equity (Parenthetical) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Shares outstanding (in shares)	112,327,533	112,181,759	112,068,705	110,241,868
Conversion of common units to common shares (in shares)	8,054	14,009	105,039
Share-based compensation issuance, net of redemptions (in shares)	137,720	99,045	106,711
Common Stock At-the-Market Program
Common shares issued during the period (in shares)			1,000
Forward Equity Sale Agreement
Common shares issued during the period (in shares)			1,614,087

Consolidated Statements of Cash

Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Cash flows from operating activities
Revenues from real estate operations received	$ 571,092	$ 542,727	$ 530,280
Construction contract and other service revenues received	100,222	78,470	94,677
Property operating expenses paid	(223,254)	(202,660)	(196,611)
Construction contract and other service expenses paid	(86,602)	(67,760)	(96,789)
General, administrative, leasing, business development and land carry costs paid	(29,072)	(31,406)	(29,347)
Interest expense paid	(65,184)	(61,471)	(67,475)
Lease incentives paid	(18,127)	(11,925)	(9,482)
Sales-type lease costs paid	(2,065)	(10,747)	0
Income taxes paid	(60)	(4)	0
Other	2,198	3,200	3,305
Net cash provided by operating activities	249,148	238,424	228,558
Cash flows from investing activities
Development and redevelopment of properties	(267,905)	(344,401)	(394,444)
Tenant improvements on operating properties	(21,488)	(28,754)	(23,809)
Other capital improvements on operating properties	(30,026)	(32,756)	(24,659)
Proceeds from property dispositions
Sale of properties	143,116	83,165	108,128
Distribution from unconsolidated real estate joint venture following contribution of properties	0	0	201,499
Proceeds from sale of investment in unconsolidated real estate joint venture	0	59,841	0
Non-operating distributions from unconsolidated real estate joint venture	1,287	3,695	22,426
Investing receivables funded	(5,880)	(272)	(11,180)
Investing receivables payments received	0	8,000	0
Leasing costs paid	(21,913)	(16,938)	(16,825)
Settlement of interest rate derivatives	0	(53,130)	0
Other	(160)	(4,242)	849
Net cash used in investing activities	(202,969)	(325,792)	(138,015)
Proceeds from debt
Revolving Credit Facility	597,000	664,000	409,000
Unsecured senior notes	1,382,614	395,264	0
Other debt proceeds	4,630	206,931	43,615
Repayments of debt
Revolving Credit Facility	(664,000)	(698,000)	(445,000)
Unsecured senior notes	(900,000)	(300,000)	0
Scheduled principal amortization	(3,860)	(4,125)	(4,310)
Other debt repayments	(238,397)	(12,031)	(77)
Deferred financing costs paid	(3,620)	(2,400)	(448)
Payments in connection with early extinguishment of debt	(95,180)	(7,029)	0
Net proceeds from issuance of common shares	0	0	46,415
Common share dividends paid	(123,527)	(123,367)	(122,657)
Distributions paid to noncontrolling interests in other consolidated entities	0	(30)	(5,890)
Distributions paid to redeemable noncontrolling interests	(2,273)	(14,357)	(1,659)
Redemption of preferred units	0	(8,800)	0
Other	(4,283)	(4,785)	(3,352)
Net cash (used in) provided by financing activities	(50,896)	91,271	(84,363)
Net (decrease) increase in cash and cash equivalents and restricted cash	(4,717)	3,903	6,180
Cash and cash equivalents and restricted cash
Beginning of year	22,033	18,130	11,950
End of year	17,316	22,033	18,130
Reconciliation of net income to net cash provided by operating activities:
Net income	81,578	102,878	200,004
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and other amortization	150,644	140,031	138,903
Impairment losses	0	1,530	329
Amortization of deferred financing costs and net debt discounts	5,224	4,272	3,639
Increase in deferred rent receivable	(19,090)	(2,168)	(4,091)
Gain on sales of real estate	(65,590)	(30,209)	(105,230)
Gain on sale of investment in unconsolidated real estate joint venture	0	(29,416)	0
Share-based compensation	7,979	6,503	6,714
Loss on early extinguishment of debt	100,626	7,306	0
Loss on interest rate derivatives	0	53,196	0
Other	(5,047)	(7,855)	(6,022)
Changes in operating assets and liabilities:
Increase in accounts receivable	(662)	(6,377)	(7,141)
Increase in prepaid expenses and other assets, net	(27,355)	(7,626)	(22,457)
Increase in accounts payable, accrued expenses and other liabilities	22,004	6,554	20,369
(Decrease) increase in rents received in advance and security deposits	(1,163)	(195)	3,541
Net cash provided by operating activities	249,148	238,424	228,558
Reconciliation of cash and cash equivalents and restricted cash:
Cash and cash equivalents	13,262	18,369	14,733
Restricted cash	4,054	3,664	3,397
Cash and cash equivalents and restricted cash	17,316	22,033	18,130
Supplemental schedule of non-cash investing and financing activities:
Increase (decrease) in accrued capital improvements, leasing and other investing activity costs	20,667	(9,421)	35,913
Reclassification of finance right-of-use asset to operating properties, net in connection with exercise of bargain purchase option	37,831	0	0
Finance right-of-use asset contributed by noncontrolling interest in joint venture	0	0	2,570
Recognition of operating right-of-use assets and related lease liabilities	328	13,340	840
Non-cash changes from property dispositions:
Investment in unconsolidated real estate joint ventures retained in property disposition	11,842	11,474	34,506
Contribution of properties to unconsolidated real estate joint venture	0	0	158,542
Increase (decrease) in fair value of derivatives applied to accumulated other comprehensive income and noncontrolling interests	6,233	(35,728)	(25,817)
Equity in other comprehensive income of an equity method investee	0	0	199
Dividends/distributions payable	31,299	31,231	31,263
Decrease in noncontrolling interests and increase in shareholders’ equity in connection with the conversion of common units into common shares	121	211	1,586
Adjustments to noncontrolling interests resulting from changes in COPLP ownership	(2,318)	(767)	167
Increase in redeemable noncontrolling interests and decrease in equity to carry redeemable noncontrolling interests at fair value	$ 1,615	$ 6,607	$ 1,749

Organization

Organization	12 Months Ended
	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	Organization Corporate Office Properties Trust (“COPT”) and subsidiaries (collectively, the “Company”, “we” or “us”) is a fully-integrated and self-managed real estate investment trust (“REIT”). We own, manage, lease, develop and selectively acquire office and data center properties. The majority of our portfolio is in locations that support the United States Government (“USG”) and its contractors, most of whom are engaged in national security, defense and information technology (“IT”) related activities servicing what we believe are growing, durable, priority missions (“Defense/IT Locations”). We also own a portfolio of office properties located in select urban/urban-like submarkets in the Greater Washington, DC/Baltimore region with durable Class-A office fundamentals and characteristics (“Regional Office”). As of December 31, 2021, our properties included the following (all references to number of properties, square footage, acres and megawatts are unaudited): • 186 properties totaling 21.7 million square feet comprised of 17.0 million square feet in 160 office properties and 4.7 million square feet in 26 single-tenant data center shells. We owned 19 of these data center shells through unconsolidated real estate joint ventures; • 11 properties under development (eight office properties and three data center shells), including one partially-operational property, that we estimate will total approximately 1.7 million square feet upon completion; • approximately 720 acres of land controlled for future development that we believe could be developed into approximately 8.9 million square feet and 43 acres of other land; and • a wholesale data center with a capacity of 19.25 megawatts that we sold on January 25, 2022. We conduct almost all of our operations and own almost all of our assets through our operating partnership, Corporate Office Properties, L.P. (“COPLP”) and subsidiaries (collectively, the “Operating Partnership”), of which COPT is the sole general partner. COPLP owns real estate directly and through subsidiary partnerships and limited liability companies (“LLCs”). In addition to owning real estate, COPLP also owns subsidiaries that provide real estate services such as property management, development and construction services primarily for our properties but also for third parties. Some of these services are performed by a taxable REIT subsidiary (“TRS”). Equity interests in COPLP are in the form of common and preferred units. As of December 31, 2021, COPT owned 98.3% of the outstanding COPLP common units (“common units”) and there were no preferred units outstanding. Common units not owned by COPT carry certain redemption rights. The number of common units owned by COPT is equivalent to the number of outstanding common shares of beneficial interest (“common shares”) of COPT, and the entitlement of common units to quarterly distributions and payments in liquidation is substantially the same as that of COPT common shareholders.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation These consolidated financial statements include the accounts of COPT, the Operating Partnership, their subsidiaries and other entities in which COPT has a majority voting interest and control. We also consolidate certain entities when control of such entities can be achieved through means other than voting rights (“variable interest entities” or “VIEs”) if we are deemed to be the primary beneficiary of such entities. We eliminate all intercompany balances and transactions in consolidation. We use the equity method of accounting when we own an interest in an entity and can exert significant influence over but cannot control the entity’s operations. We discontinue equity method accounting if our investment in an entity (and net advances) is reduced to zero unless we have guaranteed obligations of the entity or are otherwise committed to provide further financial support for the entity. When we own an equity investment in an entity and cannot exert significant influence over its operations, we measure the investment at fair value, with changes recognized through net income. For an investment without a readily determinable fair value, we measure the investment at cost, less any impairments, plus or minus changes resulting from observable price changes for an identical or similar investment of the same issuer. Reclassifications We reclassified certain amounts from prior periods to conform to the current period presentation of our consolidated financial statements with no effect on previously reported net income or equity, including amounts reclassified in conjunction with the transfer of our wholesale data center to discontinued operations in 2021. We provide disclosure regarding our discontinued operations in Note 4. Use of Estimates in the Preparation of Financial Statements We make estimates and assumptions when preparing financial statements under generally accepted accounting principles (“GAAP”). These estimates and assumptions affect various matters, including: • the reported amounts of assets and liabilities in our consolidated balance sheets as of the dates of the financial statements; • the disclosure of contingent assets and liabilities as of the dates of the financial statements; and • the reported amounts of revenues and expenses in our consolidated statements of operations during the reporting periods. Significant estimates are inherent in the presentation of our financial statements in a number of areas, including the evaluation of the collectability of accounts and deferred rent receivable, the determination of estimated useful lives of assets, the determination of lease terms, the evaluation of long-lived assets for impairment, the amount of impairment losses recognized, the allocation of property acquisition costs, the amount of revenue recognized relating to tenant improvements, the level of expense recognized in connection with share-based compensation and the determination of accounting method for investments. Actual results could differ from these and other estimates. Properties We report properties to be developed or held and used in operations at our depreciated cost, reduced for impairment losses. We capitalize direct and indirect project costs (including related compensation and other indirect costs), interest expense and real estate taxes associated with properties, or portions thereof, undergoing development or redevelopment activities. In capitalizing interest expense, if there is a specific borrowing for a property undergoing development or redevelopment activities, we apply the interest rate of that borrowing to the average accumulated expenditures that do not exceed such borrowing; for the portion of expenditures exceeding any such specific borrowing, we apply our weighted average interest rate on other borrowings to the expenditures. We continue to capitalize costs while development or redevelopment activities are underway until a property becomes “operational,” which occurs when lease terms commence (generally when the tenant has control of the leased space and we have delivered the premises to the tenant as required under the terms of such lease), but no later than one year after the cessation of major construction activities. When leases commence on portions of a newly-developed or redeveloped property in the period prior to one year from the cessation of major construction activities, we consider that property to be “partially operational.” When a property is partially operational, we allocate the costs associated with the property between the portion that is operational and the portion under development. We start depreciating costs associated with newly-developed or redeveloped properties as they become operational. For newly-developed properties, we classify improvements provided under the terms of a lease that are deemed to be landlord assets (as discussed further below) as new building development costs. Most of our leases provide for some form of improvements to leased space. When we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets. If the improvements are landlord assets, we capitalize the cost of the improvements and recognize depreciation expense over the estimated useful lives of the assets as discussed below. We recognize any payments from the tenant for such assets as lease revenue over the term of the lease. If the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset and amortize it as a reduction of rental revenue over the term of the lease. In determining whether improvements constitute landlord or tenant assets, we consider numerous factors, including whether the economic substance of the lease terms is properly reflected and whether the improvements: have value to us as real estate; are unique to the tenant or reusable by other tenants; may be altered or removed by the tenant without our consent or without compensating us for any lost fair value; or are owned, and remain, with us or the tenant at the end of the lease term. We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years We report properties disposed or classified as held for sale as discontinued operations when the disposition represents a strategic shift having a major effect on our operations and financial results (such as a disposition of a reportable segment or subsegment or major line of business). For discontinued operations, we classify for all periods presented the associated: assets as held for sale on our consolidated balance sheets; and results of operations as discontinued operations on our consolidated statements of operations (including interest expense on debt specifically identifiable to such components). For periods in which a property not reported as discontinued operations is classified as held for sale, we classify the assets of the property’s asset group as held for sale on our consolidated balance sheets. Sales of Properties We recognize gains from sales of consolidated interests in properties to non-customer third parties when we have transferred control of such interests. Impairment of Properties We assess the asset groups associated with each of our properties, including operating properties, properties in development, land held for future development, related intangible assets, right-of-use assets, deferred rents receivable and lease liabilities, for indicators of impairment quarterly or when circumstances indicate that an asset group may be impaired. If our analyses indicate that the carrying values of certain properties’ asset groups may be impaired, we perform a recovery analysis for such asset groups. For properties to be held and used, we analyze recoverability based on the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over, in most cases, a ten-year holding period. If we believe it is more likely than not that we will dispose of the properties earlier, we analyze recoverability using a probability weighted analysis of the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over the various possible holding periods. If the analysis indicates that the carrying value of a tested property’s asset group is not recoverable from its estimated future cash flows, the property’s asset group is written down to the property’s estimated fair value and an impairment loss is recognized. If and when our plans change, we revise our recoverability analyses to use the cash flows expected from the operations and eventual disposition of such property using holding periods that are consistent with our revised plans. Changes in holding periods may require us to recognize impairment losses. Fair values are estimated based on contract prices, indicative bids, discounted cash flow analyses, yield analyses or comparable sales analyses. Estimated cash flows used in our impairment analyses are based on our plans for the property and our views of market and economic conditions. The estimates consider items such as current and future market rental and occupancy rates, estimated operating and capital expenditures and recent sales data for comparable properties; most of these items are influenced by market data obtained from real estate leasing and brokerage firms and our direct experience with the properties and their markets. When we determine that a property is held for sale, we stop depreciating the property and estimate the property’s fair value, net of selling costs; if we then determine that the estimated fair value, net of selling costs, is less than the net book value of the property’s asset group, we recognize an impairment loss equal to the difference and reduce the net book value of the property’s asset group. Acquisition of Operating Properties Upon completion of operating property acquisitions, we allocate the purchase price to tangible and intangible assets and liabilities associated with such acquisitions based on our estimates of their fair values. We determine these fair values by using market data and independent appraisals available to us and making numerous estimates and assumptions. We allocate operating property acquisitions to the following components: • properties based on a valuation performed under the assumption that the property is vacant upon acquisition (the “if-vacant value”). The if-vacant value is allocated between land and buildings or, in the case of properties under development, development in progress. We also allocate additional amounts to properties for in-place tenant improvements based on our estimate of improvements per square foot provided under market leases that would be attributable to the remaining non-cancelable terms of the respective leases; • above- and below-market lease intangible assets or liabilities based on the present value (using an interest rate reflective of the risks associated with the leases acquired) of the difference between: (1) the contractual amounts to be received pursuant to the in-place leases; and (2) our estimate of fair market lease rates for the corresponding space, measured over a period equal to the remaining non-cancelable term of the lease. The capitalized above- and below-market lease values are amortized as adjustments to lease revenue over the remaining lease terms of the respective leases, and to renewal periods in the case of below-market leases; • in-place lease value based on our estimates of: (1) the present value of additional income to be realized as a result of leases being in place on the acquired properties; and (2) costs to execute similar leases. Our estimate of costs to execute similar leases includes leasing commissions, legal and other related costs; • tenant relationship value based on our evaluation of the specific characteristics of each tenant’s lease and our overall relationship with that respective tenant. Characteristics we consider in determining these values include the nature and extent of our existing business relationships with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals, among other factors; and • above- and below-market cost arrangements (such as real estate tax treaties or above- or below-market ground leases) based on the present value of the expected benefit from any such arrangements in place on the property at the time of acquisition. Leased Assets, as a Lessee We recognize right-of-use assets and lease liabilities for land and other assets leased by us from third parties for terms of at least one year. We recognize lease expense over lease terms on a straight-line basis for operating leases and on an effective interest method basis for finance leases. In determining right-of-use assets and lease liabilities, we estimate an appropriate incremental borrowing rate on a fully-collateralized basis for the terms of the leases. Since the terms under our land leases are usually significantly longer than the terms of borrowings available to us on a fully-collateralized basis, our estimates of rates for such leases require significant judgment, and consider factors such as estimated interest rates available to us on a fully-collateralized basis for shorter-termed debt and U.S. Treasury rates. We elected to apply a package of practical expedients that enabled us to carry forward, upon adoption, our historical assessments of: expired or existing leases regarding their lease classification; and whether any expired or existing contracts are, or contain, leases. We also elected a practical expedient that enabled us to avoid the need to assess whether expired or existing land easements not previously accounted for as leases are, or contain, a lease. Cash and Cash Equivalents Cash and cash equivalents include all cash and liquid investments that mature three months or less from when they are purchased. Cash equivalents are reported at cost, which approximates fair value. We maintain our cash in bank accounts in amounts that may exceed Federally insured limits at times. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions. Investments in Marketable Securities We classify marketable securities as trading securities when we have the intent to sell such securities in the near term, and classify other marketable securities as available-for-sale securities. We determine the appropriate classification of investments in marketable securities at the acquisition date and re-evaluate the classification at each balance sheet date. We report investments in marketable securities classified as trading securities at fair value (which is included in the line entitled “Prepaid expenses and other assets, net” on our consolidated balance sheets), with unrealized gains and losses recognized through earnings; on our consolidated statements of cash flows, we classify cash flows from these securities as operating activities. Receivables and Credit Losses We evaluate our receivables from customers and borrowers for collectability and recognize estimated credit losses on these receivables. We use judgment in estimating these losses based on the credit status of the entities associated with the individual receivables and payment history. Effective January 1, 2020, we adopted guidance issued by the Financial Accounting Standards Board (“FASB”) that changed how we measure credit losses for most financial assets and certain other instruments not measured at fair value through net income from an incurred loss model to an expected loss approach. We adopted this guidance using the modified retrospective transition method under which we recognized a $5.5 million allowance for credit losses by means of a cumulative-effect adjustment to cumulative distributions in excess of net income and did not adjust prior comparative reporting periods. Our consolidated statements of operations reflect adjustments for changes in our expected credit losses occurring subsequent to adoption of this guidance. Our items within the scope of this guidance included the following: • investing receivables, as disclosed in Note 8; • tenant notes receivable; • net investment in sales-type leases; • other assets comprised of non-lease revenue related accounts receivable (primarily from construction contract services) and contract assets from unbilled construction contract revenue; and • off-balance sheet credit exposures. Under this guidance, we recognize an estimate of our expected credit losses on these items as an allowance, as the guidance requires that financial assets be measured on an amortized cost basis and be presented at the net amount expected to be collected (or as a separate liability in the case of off-balance sheet credit exposures). The allowance represents the portion of the amortized cost basis that we do not expect to collect (or loss we expect to incur in the case of off-balance sheet credit exposures) due to credit over the contractual life based on available information relevant to assessing the collectability of cash flows, which includes consideration of past events, current conditions and reasonable and supportable forecasts of future economic conditions (including consideration of asset- or borrower-specific factors). The guidance requires the allowance for expected credit losses to reflect the risk of loss, even when that risk is remote. An allowance for credit losses is measured and recorded upon the initial recognition of a financial asset (or off-balance sheet credit exposure), regardless of whether it is originated or purchased. Quarterly, the expected losses are re-estimated, considering any cash receipts and changes in risks or assumptions, with resulting adjustments recognized as credit loss expense or recoveries on our consolidated statements of operations. We estimate expected credit losses for in-scope items using historical loss rate information developed for varying classifications of credit risk and contractual lives. Due to our limited quantity of items within the scope of this guidance and the unique risk characteristics of such items, we individually assign each in-scope item a credit risk classification. The credit risk classifications assigned by us are determined based on credit ratings assigned by ratings agencies (as available) or are internally-developed based on available financial information, historical payment experience, credit documentation, other publicly available information and current economic trends. In addition, for certain items in which the risk of credit loss is affected by the economic performance of a real estate development project, we develop probability weighted scenario analyses for varying levels of performance in estimating our credit loss allowance (applicable to our notes receivable from the City of Huntsville disclosed in Note 8 and a tax incremental financing obligation disclosed in Note 19). For lease revenue, if collectability is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. Prior to our adoption of the credit loss guidance discussed above, we evaluated the collectability of both interest and principal of loans whenever events or changes in circumstances indicated such amounts may not be recoverable. A loan was impaired when it was probable that we would be unable to collect all amounts due according to the existing contractual terms. When a loan was impaired, the amount of the loss accrual was calculated by comparing the carrying amount of the investment to the present value of expected future cash flows discounted at the loan’s effective interest rate and the value of any collateral under such loan. When we believe that collection of interest income on an investing or tenant note receivable is not probable, we place the receivable on nonaccrual status, meaning interest income is recognized when payments are received rather than on an accrual basis. We write off receivables when we believe the facts and circumstances indicate that continued pursuit of collection is no longer warranted. When cash is received in connection with receivables for which we have previously recognized credit losses, we recognize reductions in our credit losses. Intangible Assets and Deferred Revenue on Property Acquisitions We amortize intangible assets and deferred revenue on property acquisitions as follows: Asset Type Amortization Period Above- and below-market leases Related lease terms In-place lease value Related lease terms Tenant relationship value Estimated period of time that tenant will lease space in property Above- and below-market cost arrangements Term of arrangements We recognize the amortization of acquired above- and below-market leases as adjustments to rental revenue. We recognize the amortization of above- and below-market cost arrangements as adjustments to property operating expenses. We recognize the amortization of other intangible assets on property acquisitions as amortization expense. Deferred Leasing Costs We defer costs incurred to obtain new tenant leases or extend existing tenant leases. We amortize these costs evenly over the lease terms. We classify leasing costs paid as an investing activity on our statements of cash flows since such costs are necessary in order for us to generate long-term future cash flows from our properties. When tenant leases are terminated early, we expense any unamortized deferred leasing costs associated with those leases over the shortened term of the lease. Deferred Financing Costs We defer costs of financing arrangements and recognize these costs as interest expense over the related debt terms on a straight-line basis, which approximates the amortization that would occur under the effective interest method of amortization. We expense any unamortized loan costs when loans are retired early. We present deferred costs of financing arrangements as a direct deduction from the related debt liability, except for costs attributable to line-of-credit arrangements and interest rate derivatives, which we present in the balance sheet in the line entitled “prepaid expenses and other assets, net”. Interest Rate Derivatives Our primary objectives in using interest rate derivatives are to add stability to interest expense and to manage exposure to interest rate movements. To accomplish this objective, we use interest rate swaps as part of our interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for our making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. We use interest rate swaps to hedge the cash flows associated with interest rates on variable-rate debt borrowings. We also use forward-starting interest rate swaps to hedge the cash flows associated with interest rates on forecasted fixed-rate borrowings. We recognize all derivatives as assets or liabilities on our consolidated balance sheet at fair value. We defer all changes in the fair value of designated cash flow hedges to accumulated other comprehensive income (“AOCI”) or loss (“AOCL”), reclassifying such deferrals to interest expense as interest expense is recognized on the hedged forecasted transactions. When an interest rate swap designated as a cash flow hedge no longer qualifies for hedge accounting and the hedged transactions are probable not to occur, we recognize changes in fair value of the hedge previously deferred to AOCI or AOCL, along with any changes in fair value occurring thereafter, through earnings. We do not use interest rate derivatives for trading or speculative purposes. We manage counter-party risk by only entering into contracts with major financial institutions based upon their credit ratings and other risk factors. We use standard market conventions and techniques such as discounted cash flow analysis, option pricing models, replacement cost and termination cost in computing the fair value of derivatives at each balance sheet date. We made an accounting policy election to use an exception provided for in the applicable accounting guidance with respect to measuring counterparty credit risk for derivative instruments; this election enables us to measure the fair value of groups of assets and liabilities associated with derivative instruments consistently with how market participants would price the net risk exposure as of the measurement date. Noncontrolling Interests Our consolidated noncontrolling interests are comprised of interests in COPLP not owned by COPT and interests in consolidated real estate joint ventures not owned by us (discussed further in Note 6). We evaluate whether noncontrolling interests are subject to redemption features outside of our control. We classify noncontrolling interests that are currently redeemable for cash at the option of the holders or are probable of becoming redeemable as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets; we adjust these interests each period to the greater of their fair value or carrying amount (initial amount as adjusted for allocations of income and losses and contributions and distributions), with a corresponding offset to additional paid-in capital on our consolidated balance sheets. Our other noncontrolling interests are reported in the equity section of our consolidated balance sheets. Revenue Recognition Lease and Other Property Revenue We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases usually include options under which the tenant may renew its lease based on market rates at the time of renewal, which are then typically subject to further negotiation. These leases occasionally provide the tenant with an option to terminate its lease early usually for a defined termination fee. Most of our lease revenue is from fixed contractual payments defined under the lease that, in most cases, escalate annually over the term of the lease. Our lease revenue also includes variable lease payments predominantly for tenant reimbursements of property operating expenses and lease termination fees. Property operating expense reimbursement structures vary, with some tenants responsible for all of a property’s expenses, while others are responsible for their share of a property’s expense only to the extent such expenses exceed amounts defined in the lease (which are derived from the property’s historical expense levels). Lease termination fees in most cases result from a tenant’s exercise of an existing right under a lease. Upon lease commencement, we evaluate leases to determine if they meet criteria set forth in lease accounting guidance for classification as sales-type leases or direct financing leases; if a lease meets none of these criteria, we classify the lease as an operating lease. Upon commencement of sales-type leases, we derecognize the underlying asset, recognizing in its place a net investment in the lease equal to the sum of the lease receivable and the present value of any unguaranteed residual asset and recognize any selling profit or loss created as a result of the difference between those two amounts. Similarly, for direct financing leases, the lessor derecognizes the underlying asset and recognizes a net investment in the lease, but, unlike in a sales-type lease, defers profit and amortizes it as interest income over the lease term. Our leases of properties as lessor are predominantly classified as operating leases, for which the underlying asset remains on our balance sheet and is depreciated consistently with other owned assets, with income recognized as described further below. We recognize minimum rents on operating leases, net of abatements, on a straight-line basis over the term of tenant leases. A lease term commences when: (1) the tenant has control of the leased space (legal right to use the property); and (2) we have delivered the premises to the tenant as required under the terms of the lease. The term of a lease includes the noncancellable periods of the lease along with periods covered by: (1) a tenant option to extend the lease if the tenant is reasonably certain to exercise that option; (2) a tenant option to terminate the lease if the tenant is reasonably certain not to exercise that option; and (3) an option to extend (or not to terminate) the lease in which exercise of the option is controlled by us as the lessor. When assessing the expected lease end date, we use judgment in contemplating the significance of: any penalties a tenant may incur should it choose not to exercise any existing options to extend the lease or exercise any existing options to terminate the lease; and economic incentives for the tenant based on any existing contract, asset, entity or market-based factors in the lease. While a significant portion of our portfolio is leased to the USG, and the majority of those leases consist of a series of one-year renewal options, or provide for early termination rights, we have concluded that exercise of existing renewal options, or continuation of such leases without exercising early termination rights, is reasonably certain for most of these leases. We report the amount by which our minimum rental revenue recognized on a straight-line basis under leases exceeds the contractual rent billings associated with such leases as deferred rent receivable on our consolidated balance sheets. Amounts by which our minimum rental revenue recognized on a straight-line basis under leases are less than the contractual rent billings associated with such leases are reported in liabilities as deferred revenue associated with operating leases on our consolidated balance sheets. In connection with a tenant’s entry into, or modification of, a lease, if we make cash payments to, or on behalf of, the tenant for purposes other than funding the construction of landlord assets, we generally defer the amount of such payments as lease incentives. As discussed above, when we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets; if the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset. We amortize lease incentives as a reduction of rental revenue over the term of the lease. If collectability under a lease is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. We recognize lease revenue associated with tenant expense recoveries in the same periods in which we incur the related expenses, including tenant reimbursements of property taxes, utilities and other property operating expenses. We recognize fees received for lease terminations as revenue and write off against such revenue any (1) deferred rents receivable, and (2) deferred revenue, lease incentives and intangible assets that are amortizable into rental revenue associated with the leases; the resulting net amount is the net revenue from the early termination of the leases. When a tenant’s lease for space in a property is terminated early but the tenant continues to lease such space under a new or modified lease in the property, the net revenue from the early termination of the lease is recognized evenly over the remaining life of the new or modified lease in place on that property. Effective January 1, 2019, we adopted guidance issued by the FASB setting forth principles for the recognition, measurement, presentation and disclosure of leases, which required lessors of real estate to account for leases using an approach substantially equivalent to guidance previously in place for operating leases, direct financing leases and sales-type leases. Upon adoption, we elected to apply a package of practical expedients that enabled us to carry

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value MeasurementsAccounting standards define fair value as the exit price, or the amount that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. The standards also establish a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of us. Unobservable inputs are inputs that reflect our assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available in the circumstances. The hierarchy of these inputs is broken down into three levels: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs include (1) quoted prices for similar assets or liabilities in active markets, (2) quoted prices for identical or similar assets or liabilities in inactive markets and (3) inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly; and Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is most significant to the fair value measurement. Recurring Fair Value Measurements We have a non-qualified elective deferred compensation plan for Trustees and certain members of our management team that, prior to December 31, 2019, permitted participants to defer up to 100% of their compensation on a pre-tax basis and receive a tax-deferred return on such deferrals. Effective December 31, 2019, no new investments of deferred compensation were eligible for the plan. The assets held in the plan (comprised primarily of mutual funds and equity securities) and the corresponding liability to the participants are measured at fair value on a recurring basis on our consolidated balance sheets using quoted market prices, as are other marketable securities that we hold. The balance of the plan, which was fully funded, totaled $2.6 million as of December 31, 2021 and $3.0 million as of December 31, 2020, and is included in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets along with an insignificant amount of other marketable securities. The offsetting liability associated with the plan is adjusted to fair value at the end of each accounting period based on the fair value of the plan assets and reported in “other liabilities” on our consolidated balance sheets. The assets of the plan are classified in Level 1 of the fair value hierarchy, while the offsetting liability is classified in Level 2 of the fair value hierarchy. The fair values of our interest rate derivatives are determined using widely accepted valuation techniques, including a discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate market data and implied volatilities in such interest rates. While we determined that the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our interest rate derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default. However, as of December 31, 2021 and 2020, we assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivatives and determined that these adjustments were not significant. As a result, we determined that our interest rate derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The carrying values of cash and cash equivalents, restricted cash, accounts receivable, other assets (excluding investing receivables) and accounts payable and accrued expenses are reasonable estimates of their fair values because of the short maturities of these instruments. The fair values of our investing receivables, as disclosed in Note 8, were based on the discounted estimated future cash flows of the loans (categorized within Level 3 of the fair value hierarchy); the discount rates used approximate current market rates for loans with similar maturities and credit quality, and the estimated cash payments include scheduled principal and interest payments. For our disclosure of debt fair values in Note 10, we estimated the fair value of our unsecured senior notes based on quoted market rates for our senior notes (categorized within Level 1 of the fair value hierarchy) and estimated the fair value of our other debt based on the discounted estimated future cash payments to be made on such debt (categorized within Level 3 of the fair value hierarchy); the discount rates used approximate current market rates for loans, or groups of loans, with similar maturities and credit quality, and the estimated future payments include scheduled principal and interest payments. Fair value estimates are made as of a specific point in time, are subjective in nature and involve uncertainties and matters of significant judgment. For additional fair value information, refer to Note 8 for investing receivables, Note 10 for debt and Note 11 for interest rate derivatives. The table below sets forth our financial assets and liabilities accounted for at fair value on a recurring basis as of December 31, 2021 and 2020 and the hierarchy level of inputs used in measuring their respective fair values under applicable accounting standards (in thousands): Description Quoted Prices in Significant Other Significant Total December 31, 2021: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 2,485 $ — $ — $ 2,485 Other 71 — — 71 Other marketable securities (1) 33 — — 33 Interest rate derivatives (1) — 355 — 355 Total assets $ 2,589 $ 355 $ — $ 2,944 Liabilities: Deferred compensation plan liability (2) $ — $ 2,556 $ — $ 2,556 Interest rate derivatives — 3,644 — 3,644 Total liabilities $ — $ 6,200 $ — $ 6,200 December 31, 2020: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 3,008 $ — $ — $ 3,008 Other 19 — — 19 Other marketable securities (1) 30 — — 30 Total assets $ 3,057 $ — $ — $ 3,057 Liabilities: Deferred compensation plan liability (2) $ — $ 3,027 $ — $ 3,027 Interest rate derivatives — 9,522 — 9,522 Total liabilities $ — $ 12,549 $ — $ 12,549 (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	12 Months Ended
	Dec. 31, 2021
Real Estate [Abstract]
Properties, Net	Properties, Net Operating properties, net consisted of the following (in thousands): December 31, 2021 2020 Land $ 572,900 $ 522,219 Buildings and improvements 3,670,133 3,444,804 Less: Accumulated depreciation (1,152,523) (1,052,007) Operating properties, net $ 3,090,510 $ 2,915,016 Discontinued Operations As of December 31, 2021, our wholesale data center was under contract to be sold, and the sale was completed on January 25, 2022. Our wholesale data center, a separate reportable segment, is reported herein as discontinued operations. The table below sets forth the components of our wholesale data center’s assets classified as held for sale on our consolidated balance sheets (in thousands): December 31, 2021 2020 Properties, net $ 191,857 $ 200,264 Deferred rent receivable 462 1,025 Intangible assets on property acquisitions, net 73 95 Deferred leasing costs, net 307 436 Assets held for sale, net $ 192,699 $ 201,820 The table below sets forth our wholesale data center’s results of operations included in discontinued operations on our consolidated statements of operations and its operating and investing cash flows included on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, 2021 2020 2019 (in thousands) Revenues from real estate operations $ 30,490 $ 27,011 $ 29,405 Property operating expenses (16,842) (13,044) (12,694) Depreciation and amortization associated with real estate operations (10,290) (11,690) (12,061) Discontinued operations 3,358 2,277 4,650 Cash flows from operating activities $ 10,930 $ 16,051 $ 18,626 Cash flows from investing activities $ (1,912) $ (11,485) $ (805) 2021 Dispositions On June 2, 2021, we sold a 90% interest in two data center shell properties in Northern Virginia based on an aggregate property value of $118.8 million and retained a 10% interest in the properties through B RE COPT DC JV III LLC (“BRE-COPT 3”), a newly-formed joint venture. Our partner in the joint venture acquired the 90% interest from us for $106.9 million. We account for our interest in the joint venture using the equity method of accounting as described further in Note 6. We recognized a gain on sale of $40.2 million. On December 30, 2021, we sold a property that was previously removed from service from our data center shells sub-segment for $30.0 million and recognized a gain on sale of $25.9 million. 2021 Development Activities In 2021, we placed into service 766,000 square feet in eight newly-developed properties. As of December 31, 2021, we had 11 properties under development, including one partially-operational property, that we estimate will total 1.7 million square feet upon completion. 2020 Dispositions On October 30, 2020, we sold a 90% interest in two data center shell properties in Northern Virginia based on an aggregate property value of $89.7 million and retained a 10% interest in the properties through B RE COPT DC JV II LLC (“BRE-COPT 2”), a newly-formed joint venture. Our partner in the joint venture acquired the 90% interest from us for $80.7 million. We account for our interest in the joint venture using the equity method of accounting as described further in Note 6. We recognized a gain on sale of $30.0 million. 2020 Development Activities In 2020, we placed into service 1.8 million square feet in 11 newly-developed properties, 42,000 square feet in expansions of three fully-operational properties and 21,000 square feet in a redeveloped property. In the third quarter of 2020, we concluded that we no longer expected to develop a property in Baltimore, Maryland. As a result, we recognized an impairment loss on previously incurred pre-development costs of $1.5 million. 2019 Dispositions In 2019, we sold, through a series of transactions, a 90% interest in nine data center shells in Northern Virginia based on an aggregate property value of $345.1 million, retaining a 10% interest in the properties through BREIT COPT DC JV LLC (“BREIT-COPT”), a newly-formed joint venture. The transactions for seven of these properties were completed on June 20, 2019 and the remaining two properties on December 5, 2019. Our partner in the joint venture acquired the 90% interest from us for $310.6 million. We account for our interest in the joint venture using the equity method of accounting as described further in Note 6. We recognized a gain on sale of $105.2 million. 2019 Development Activities In 2019, we placed into service 1.1 million square feet in nine newly-developed properties and 85,000 square feet in one property under redevelopment.

Leases

Leases	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2021 2020 2019 Fixed $ 436,768 $ 404,244 $ 392,341 Variable 116,900 104,870 100,824 $ 553,668 $ 509,114 $ 493,165 (1) Excludes lease revenue from discontinued operations of which $22.3 million, $21.3 million and $20.0 million was fixed and $8.2 million, $5.7 million and $9.3 million was variable for 2021, 2020 and 2019, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 36% in 2021 and 37% in 2020 and 2019 of our total lease revenue, and 26% in 2021 and 27% in 2020 and 2019 of our fixed lease revenue. Our lease revenue from the USG in 2021, 2020 and 2019 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 16). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2021 Year Ending December 31, Operating leases Sales-type leases 2022 $ 430,910 $ 960 2023 391,551 960 2024 344,256 960 2025 256,725 960 2026 193,051 960 Thereafter 939,463 3,556 Total contractual payments $ 2,555,956 8,356 Less: Amount representing interest (2,162) Net investment in sales-type leases $ 6,194 Lessee Arrangements As of December 31, 2021, our balance sheet included $40.6 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 27 years to 79 years (excluding extension options). As of December 31, 2021, our right-of-use assets included: • $10.9 million for land in a business park in Huntsville, Alabama under 16 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 41 to 50 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.9 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 78 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 27 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.1 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 61 to 72 years; • $5.1 million for data center space in Phoenix, Arizona with a remaining term of three years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.2 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 46 years, all of the rent on which was previously paid. Our property right-of-use assets consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 38,361 $ 40,570 Finance leases - Property (1) Property - finance right-of-use assets 2,238 40,425 Total right-of-use assets $ 40,599 $ 80,995 (1) On October 22, 2021, we acquired land leased in Washington, D.C., for which we had a $37.8 million right-of-use asset as of December 31, 2021, for a nominal amount under a bargain purchase option. Property lease liabilities consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 29,342 $ 30,746 Finance leases - Property Other liabilities — 28 Total lease liabilities $ 29,342 $ 30,774 As of December 31, 2021, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.16%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2021 2020 2019 Operating lease cost Property leases - fixed Property operating expenses $ 4,011 $ 2,413 $ 1,664 Property leases - variable Property operating expenses 45 127 4 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 34 30 $ 4,087 $ 2,574 $ 1,698 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,206 $ 1,694 $ 1,004 Financing cash flows for financing leases $ 14 $ 674 $ 14 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2021 2022 $ 3,297 2023 3,352 2024 3,403 2025 1,749 2026 1,530 Thereafter 122,448 Total lease payments 135,779 Less: Amount representing interest (106,437) Lease liability $ 29,342
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2021 2020 2019 Fixed $ 436,768 $ 404,244 $ 392,341 Variable 116,900 104,870 100,824 $ 553,668 $ 509,114 $ 493,165 (1) Excludes lease revenue from discontinued operations of which $22.3 million, $21.3 million and $20.0 million was fixed and $8.2 million, $5.7 million and $9.3 million was variable for 2021, 2020 and 2019, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 36% in 2021 and 37% in 2020 and 2019 of our total lease revenue, and 26% in 2021 and 27% in 2020 and 2019 of our fixed lease revenue. Our lease revenue from the USG in 2021, 2020 and 2019 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 16). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2021 Year Ending December 31, Operating leases Sales-type leases 2022 $ 430,910 $ 960 2023 391,551 960 2024 344,256 960 2025 256,725 960 2026 193,051 960 Thereafter 939,463 3,556 Total contractual payments $ 2,555,956 8,356 Less: Amount representing interest (2,162) Net investment in sales-type leases $ 6,194 Lessee Arrangements As of December 31, 2021, our balance sheet included $40.6 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 27 years to 79 years (excluding extension options). As of December 31, 2021, our right-of-use assets included: • $10.9 million for land in a business park in Huntsville, Alabama under 16 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 41 to 50 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.9 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 78 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 27 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.1 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 61 to 72 years; • $5.1 million for data center space in Phoenix, Arizona with a remaining term of three years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.2 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 46 years, all of the rent on which was previously paid. Our property right-of-use assets consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 38,361 $ 40,570 Finance leases - Property (1) Property - finance right-of-use assets 2,238 40,425 Total right-of-use assets $ 40,599 $ 80,995 (1) On October 22, 2021, we acquired land leased in Washington, D.C., for which we had a $37.8 million right-of-use asset as of December 31, 2021, for a nominal amount under a bargain purchase option. Property lease liabilities consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 29,342 $ 30,746 Finance leases - Property Other liabilities — 28 Total lease liabilities $ 29,342 $ 30,774 As of December 31, 2021, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.16%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2021 2020 2019 Operating lease cost Property leases - fixed Property operating expenses $ 4,011 $ 2,413 $ 1,664 Property leases - variable Property operating expenses 45 127 4 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 34 30 $ 4,087 $ 2,574 $ 1,698 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,206 $ 1,694 $ 1,004 Financing cash flows for financing leases $ 14 $ 674 $ 14 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2021 2022 $ 3,297 2023 3,352 2024 3,403 2025 1,749 2026 1,530 Thereafter 122,448 Total lease payments 135,779 Less: Amount representing interest (106,437) Lease liability $ 29,342
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2021 2020 2019 Fixed $ 436,768 $ 404,244 $ 392,341 Variable 116,900 104,870 100,824 $ 553,668 $ 509,114 $ 493,165 (1) Excludes lease revenue from discontinued operations of which $22.3 million, $21.3 million and $20.0 million was fixed and $8.2 million, $5.7 million and $9.3 million was variable for 2021, 2020 and 2019, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 36% in 2021 and 37% in 2020 and 2019 of our total lease revenue, and 26% in 2021 and 27% in 2020 and 2019 of our fixed lease revenue. Our lease revenue from the USG in 2021, 2020 and 2019 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 16). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2021 Year Ending December 31, Operating leases Sales-type leases 2022 $ 430,910 $ 960 2023 391,551 960 2024 344,256 960 2025 256,725 960 2026 193,051 960 Thereafter 939,463 3,556 Total contractual payments $ 2,555,956 8,356 Less: Amount representing interest (2,162) Net investment in sales-type leases $ 6,194 Lessee Arrangements As of December 31, 2021, our balance sheet included $40.6 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 27 years to 79 years (excluding extension options). As of December 31, 2021, our right-of-use assets included: • $10.9 million for land in a business park in Huntsville, Alabama under 16 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 41 to 50 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.9 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 78 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 27 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.1 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 61 to 72 years; • $5.1 million for data center space in Phoenix, Arizona with a remaining term of three years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.2 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 46 years, all of the rent on which was previously paid. Our property right-of-use assets consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 38,361 $ 40,570 Finance leases - Property (1) Property - finance right-of-use assets 2,238 40,425 Total right-of-use assets $ 40,599 $ 80,995 (1) On October 22, 2021, we acquired land leased in Washington, D.C., for which we had a $37.8 million right-of-use asset as of December 31, 2021, for a nominal amount under a bargain purchase option. Property lease liabilities consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 29,342 $ 30,746 Finance leases - Property Other liabilities — 28 Total lease liabilities $ 29,342 $ 30,774 As of December 31, 2021, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.16%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2021 2020 2019 Operating lease cost Property leases - fixed Property operating expenses $ 4,011 $ 2,413 $ 1,664 Property leases - variable Property operating expenses 45 127 4 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 34 30 $ 4,087 $ 2,574 $ 1,698 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,206 $ 1,694 $ 1,004 Financing cash flows for financing leases $ 14 $ 674 $ 14 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2021 2022 $ 3,297 2023 3,352 2024 3,403 2025 1,749 2026 1,530 Thereafter 122,448 Total lease payments 135,779 Less: Amount representing interest (106,437) Lease liability $ 29,342
Leases	Leases Lessor Arrangements We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases encompass all, or a portion, of properties, with various expiration dates. Our lease revenue is comprised of: fixed lease revenue, including contractual rent billings under leases recognized on a straight-line basis over lease terms and amortization of lease incentives and above- and below- market lease intangibles; and variable lease revenue, including tenant expense recoveries, lease termination revenue and other revenue from tenants that is not fixed under leases. The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2021 2020 2019 Fixed $ 436,768 $ 404,244 $ 392,341 Variable 116,900 104,870 100,824 $ 553,668 $ 509,114 $ 493,165 (1) Excludes lease revenue from discontinued operations of which $22.3 million, $21.3 million and $20.0 million was fixed and $8.2 million, $5.7 million and $9.3 million was variable for 2021, 2020 and 2019, respectively. A significant concentration of our lease revenue from continuing operations was earned from our largest tenant, the USG, including 36% in 2021 and 37% in 2020 and 2019 of our total lease revenue, and 26% in 2021 and 27% in 2020 and 2019 of our fixed lease revenue. Our lease revenue from the USG in 2021, 2020 and 2019 was earned primarily from properties in the Fort Meade/BW Corridor, Lackland Air Force Base and Northern Virginia Defense/IT (“NoVA Defense/IT”) reportable sub-segments (see Note 16). Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2021 Year Ending December 31, Operating leases Sales-type leases 2022 $ 430,910 $ 960 2023 391,551 960 2024 344,256 960 2025 256,725 960 2026 193,051 960 Thereafter 939,463 3,556 Total contractual payments $ 2,555,956 8,356 Less: Amount representing interest (2,162) Net investment in sales-type leases $ 6,194 Lessee Arrangements As of December 31, 2021, our balance sheet included $40.6 million in right-of-use assets associated primarily with land leased from third parties underlying certain properties that we are operating. The land leases have long durations with remaining terms ranging from 27 years to 79 years (excluding extension options). As of December 31, 2021, our right-of-use assets included: • $10.9 million for land in a business park in Huntsville, Alabama under 16 leases through our LW Redstone Company, LLC joint venture, with remaining terms ranging from 41 to 50 years and options to renew for an additional 25 years that were not included in the term used in determining the asset balance; • $9.9 million for land underlying operating office properties in Washington, D.C. under two leases with remaining terms of approximately 78 years; • $6.4 million for land underlying a parking garage in Baltimore, Maryland under a lease with a remaining term of 27 years and an option to renew for an additional 49 years that was included in the term used in determining the asset balance; • $6.1 million for land in a research park in College Park, Maryland under four leases through our M Square Associates, LLC joint venture, all of the rent on which was previously paid. These leases had remaining terms ranging from 61 to 72 years; • $5.1 million for data center space in Phoenix, Arizona with a remaining term of three years and an option to renew for an additional five years that were not included in the term used in determining the asset balance; and • $2.2 million for other land underlying operating properties in our Fort Meade/BW Corridor sub-segment under two leases with remaining terms of approximately 46 years, all of the rent on which was previously paid. Our property right-of-use assets consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 38,361 $ 40,570 Finance leases - Property (1) Property - finance right-of-use assets 2,238 40,425 Total right-of-use assets $ 40,599 $ 80,995 (1) On October 22, 2021, we acquired land leased in Washington, D.C., for which we had a $37.8 million right-of-use asset as of December 31, 2021, for a nominal amount under a bargain purchase option. Property lease liabilities consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 29,342 $ 30,746 Finance leases - Property Other liabilities — 28 Total lease liabilities $ 29,342 $ 30,774 As of December 31, 2021, our operating leases had a weighted average remaining lease term of 51 years and a weighted average discount rate of 7.16%. The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2021 2020 2019 Operating lease cost Property leases - fixed Property operating expenses $ 4,011 $ 2,413 $ 1,664 Property leases - variable Property operating expenses 45 127 4 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 34 30 $ 4,087 $ 2,574 $ 1,698 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,206 $ 1,694 $ 1,004 Financing cash flows for financing leases $ 14 $ 674 $ 14 Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2021 2022 $ 3,297 2023 3,352 2024 3,403 2025 1,749 2026 1,530 Thereafter 122,448 Total lease payments 135,779 Less: Amount representing interest (106,437) Lease liability $ 29,342

Real Estate Joint Ventures

Real Estate Joint Ventures	12 Months Ended
	Dec. 31, 2021
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 pertaining to our investments in consolidated real estate joint ventures as of December 31, 2021 (dollars in thousands): Nominal Ownership % December 31, 2021 (1) Date Acquired Total Encumbered Assets Total Liabilities Entity Location LW Redstone Company, LLC (2) 3/23/2010 85% Huntsville, Alabama $ 478,739 $ 89,589 $ 93,730 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 165,806 — 1,406 M Square Associates, LLC 6/26/2007 50% College Park, Maryland 101,515 60,795 52,589 $ 746,060 $ 150,384 $ 147,725 (1) Excludes amounts eliminated in consolidation. (2) As discussed below, we fund all capital requirements. Our partner generally receives distributions of the first $1.2 million of annual operating cash flows and we receive the remainder. Each of these joint ventures are engaged in the development and operation of real estate. We concluded that these joint ventures are variable interest entities. We consolidate these joint ventures because of our: (1) power to direct the matters that most significantly impact their activities, including development, leasing and management of their properties; and (2) right to receive returns on our fundings and, in many cases, the obligation to fund the activities of the ventures to the extent that third-party financing is not obtained, both of which could be potentially significant to them. With regard to these joint ventures: • for LW Redstone Company, LLC, we anticipate funding certain infrastructure costs (up to a maximum of $76.0 million excluding accrued interest thereon) due to be reimbursed by the City of Huntsville as discussed further in Note 8. We had advanced $68.1 million to the City through December 31, 2021 to fund such costs. We also expect to fund additional development costs through equity contributions to the extent that third party financing is not obtained. Our partner was credited with $9.0 million in invested capital upon formation and is not required to make, nor has it made, additional equity contributions. Cash flows are generally distributed to the partners as follows: (1) cumulative preferred returns of 13.5% on our partner’s invested capital; (2) cumulative preferred returns of 13.5% on our invested capital; (3) return of our invested capital; (4) return of our partner’s invested capital; and (5) any remaining residual 85% to us and 15% to our partner. Our partner has the right to require us to acquire its interest for fair value; accordingly, we classify the fair value of our partner’s interest as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets. We have the right to acquire our partner’s interest at fair value upon the earlier of five years following the project’s achievement of a construction commencement threshold of 4.4 million square feet or March 2040; the project had achieved approximately 2.3 million square feet of construction commencement through December 31, 2021. Our partner has the right to receive some or all of the consideration for the acquisition of its interests in the form of common units in COPLP; • for Stevens Investors, LLC, net cash flows of this entity will be distributed to the partners as follows: (1) member loans and accrued interest; (2) pro rata return of the partners’ capital; (3) pro rata return of the partners’ respective unpaid preferred returns; and (4) varying splits of 85% to 60% to us and the balance to our partners as we reach specified return hurdles. As of December 31, 2021, we also had a $112.0 million construction loan to the joint venture, which is eliminated in consolidation, that carries an interest rate of LIBOR plus 2.35% and had a balance of $92.2 million; the loan matures on August 11, 2024, and we have priority for repayment in full of borrowings and accrued interest on the loan over partner distributions of any future refinancing proceeds or other available cash flows. Our partners have the right to require us to acquire some or all of their interests for fair value for a defined period of time from December 2021 until June 2023; accordingly, we classify the fair value of our partners’ interest as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets. We and our partners each have the right to acquire each other’s interests at fair value beginning in December 2023. Our partners have the right to receive some or all of the consideration for the acquisition of their interests in the form of common units in COPLP; and • for M Square Associates, LLC, net cash flows of this entity are distributed to the partners as follows: (1) member loans and accrued interest; (2) our preferred return and capital contributions used to fund infrastructure costs; (3) the partners’ preferred returns and capital contributions used to fund all other costs in proportion to their respective accrued returns and capital accounts; and (4) residual amounts distributed 50% to each member. We disclose the activity of our redeemable noncontrolling interests in Note 12. The ventures discussed above include only ones in which parties other than us own interests. Unconsolidated Real Estate Joint Ventures The table below sets forth information pertaining to our investments in unconsolidated real estate joint ventures accounted for using the equity method of accounting (dollars in thousands): Date Acquired Nominal Ownership % Number of Properties Carrying Value of Investment (1) Entity December 31, 2021 December 31, 2020 BRE-COPT 2 (2) 10/30/2020 10% 8 $ 15,579 $ 15,988 BREIT-COPT 6/20/2019 10% 9 12,460 13,315 BRE-COPT 3 6/2/2021 10% 2 11,850 — 19 $ 39,889 $ 29,303 (1) Included in the line entitled “investment in unconsolidated real estate joint ventures” on our consolidated balance sheets. (2) Our investment in BRE-COPT 2 was lower than our share of the joint venture’s equity by $7.2 million as of December 31, 2021 and $7.4 million as of December 31, 2020 due to a difference between our cost basis and our share of the joint venture’s underlying equity in its net assets. We recognize adjustments to our share of the joint venture’s earnings and losses resulting from this basis difference in the underlying assets of the joint venture. These joint ventures operate triple-net leased, single-tenant data center shell properties in Northern Virginia. With regard to these joint ventures: • BRE-COPT 2 was formed in 2020, when, as described further in Note 4, we sold a 90% interest in two properties and retained a 10% interest in the properties through the joint venture. As discussed below, this joint venture acquired an additional six properties through a transaction completed on December 22, 2020; • BREIT-COPT was formed in 2019, when, as described further in Note 4, we sold a 90% interest in nine properties and retained a 10% interest in the properties through the joint venture; and • BRE-COPT 3 was formed in 2021, when, as described further in Note 4, we sold a 90% interest in two properties and retained a 10% interest in the properties through the joint venture. We concluded that these joint ventures are variable interest entities. Under the terms of the joint venture agreements, we and our partners receive returns in proportion to our investments, and our maximum exposure to losses is limited to our investments, subject to certain indemnification obligations with respect to nonrecourse debt secured by the properties. The nature of our involvement in the activities of the joint venture does not give us power over decisions that significantly affect its economic performance. We previously also owned a 50% interest in GI-COPT DC Partnership LLC (“GI-COPT”), an unconsolidated joint venture that owned and operated six triple-net leased, single tenant data center shell properties in Northern Virginia. On December 22, 2020, we sold, through a series of transactions, 80% of our 50% interests in the properties and associated mortgage debt that we owned through GI-COPT. We received $60 million in proceeds and a 10% retained interest in the LLCs through BRE-COPT 2, and recognized a gain of $29.4 million on the sale of these interests. GI-COPT was dissolved upon completion of these transactions.

Intangible Assets on Property A

Intangible Assets on Property Acquisitions	12 Months Ended
	Dec. 31, 2021
Intangible Assets on Property Acquisitions
Intangible Assets on Property Acquisitions	Intangible Assets on Property Acquisitions Intangible assets on property acquisitions consisted of the following (in thousands): December 31, 2021 December 31, 2020 Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net In-place lease value $ 125,591 $ 118,983 $ 6,608 $ 128,693 $ 120,010 $ 8,683 Tenant relationship value 58,082 50,701 7,381 58,082 48,163 9,919 Above-market leases 13,718 13,435 283 13,718 13,380 338 Other 1,333 1,038 295 1,333 1,024 309 $ 198,724 $ 184,157 $ 14,567 $ 201,826 $ 182,577 $ 19,249

Investing Receivables

Investing Receivables	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Investing Receivables	Investing Receivables Investing receivables consisted of the following (in thousands): December 31, 2021 2020 Notes receivable from the City of Huntsville $ 77,784 $ 65,564 Other investing loans receivable 6,041 6,041 Amortized cost basis 83,825 71,605 Allowance for credit losses (1,599) (2,851) Investing receivables, net $ 82,226 $ 68,754 The balances above include accrued interest receivable, net of allowance for credit losses, of $5.3 million as of December 31, 2021 and $4.8 million as of December 31, 2020. Our notes receivable from the City of Huntsville funded infrastructure costs in connection with our LW Redstone Company, LLC joint venture (see Note 6) and carry an interest rate of 9.95%. These notes and the accrued and unpaid interest thereon, which compounds annually on March 1, will be repaid using the real estate taxes generated by the properties developed by the joint venture. When these tax revenues are sufficient to cover the debt service on a certain increment of municipal bonds, the City of Huntsville will be required to issue bonds to repay the notes and the accrued and unpaid interest thereon. Each note has a maturity date of the earlier of 30 years from the date issued or the expiration of the tax increment district comprising the developed properties in 2045. Our other investing loans receivable carry an interest rate of 8.0% and mature in 2022. The fair value of these receivables was approximately $84 million as of December 31, 2021 and $73 million as of December 31, 2020.

Prepaid Expenses and Other Asse

Prepaid Expenses and Other Assets, Net	12 Months Ended
	Dec. 31, 2021
Prepaid Expense and Other Assets [Abstract]
Prepaid Expenses and Other Assets, Net	Prepaid Expenses and Other Assets, Net Prepaid expenses and other assets, net consisted of the following (in thousands): December 31, 2021 2020 Lease incentives, net $ 51,486 $ 35,642 Construction contract costs in excess of billings, net 22,384 10,343 Prepaid expenses 20,058 19,690 Furniture, fixtures and equipment, net 9,599 10,433 Net investment in sales-type leases 6,194 6,573 Non-real estate equity investments 5,544 5,509 Restricted cash 4,054 3,664 Marketable securities in deferred compensation plan 2,556 3,027 Deferred tax asset, net 1,841 1,989 Deferred financing costs, net (1) 1,314 2,439 Other assets 5,708 5,274 Prepaid expenses and other assets, net $ 130,738 $ 104,583 (1) Represents deferred costs, net of accumulated amortization, attributable to our Revolving Credit Facility and interest rate derivatives . Deferred tax asset, net reported above includes the following tax effects of temporary differences and carry forwards of our TRS (in thousands): December 31, 2021 2020 Operating loss carry forward $ 1,835 $ 2,087 Property 30 103 Valuation allowance (24) (201) Deferred tax asset, net $ 1,841 $ 1,989 We recognize a valuation allowance on our deferred tax asset if we believe that all, or some portion, of the asset may not be realized. An increase or decrease in the valuation allowance resulting from a change in circumstances that causes a change in our judgment about the realizability of our deferred tax asset is included in income. We believe it is more likely than not that the results of future operations in our TRS will generate sufficient taxable income to realize our December 31, 2021 net deferred tax asset.

Debt, Net

Debt, Net	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Debt, Net	Debt, Net Debt Summary Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of December 31, December 31, 2021 2021 2020 Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed rate mortgage debt (2) $ 86,960 $ 139,991 3.82% - 4.62% (3) 2023-2026 Variable rate secured debt 33,667 115,119 LIBOR + 1.45% to 1.55% (4) 2025-2026 Total mortgage and other secured debt 120,627 255,110 Revolving Credit Facility 76,000 143,000 LIBOR + 0.775% to 1.45% (5) March 2023 Term Loan Facility 299,420 398,447 LIBOR + 1.00% to 1.65% (6) December 2022 Unsecured Senior Notes 2.25%, $400,000 aggregate principal 395,491 394,464 2.25% (7) March 2026 2.00%, $400,000 aggregate principal 396,512 — 2.00% (8) January 2029 2.75%, $600,000 aggregate principal 589,060 — 2.75% (9) April 2031 2.90%, $400,000 aggregate principal 394,441 — 2.90% (10) December 2033 3.60%, $350,000 aggregate principal — 348,888 3.60% (11) N/A 5.25%, $250,000 aggregate principal — 248,194 5.25% (12) N/A 5.00%, $300,000 aggregate principal — 297,915 5.00% (13) N/A Unsecured note payable 753 900 0% (14) May 2026 Total debt, net $ 2,272,304 $ 2,086,918 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $5.8 million as of December 31, 2021 and $5.9 million as of December 31, 2020. (2) Certain of the fixed rate mortgages carry interest rates that, upon assumption, were above or below market rates and therefore were recorded at their fair value based on applicable effective interest rates. The carrying values of these loans reflect net unamortized premiums totaling $155,000 as of December 31, 2020. (3) The weighted average interest rate on our fixed rate mortgage debt was 4.07% as of December 31, 2021. (4) The weighted average interest rate on our variable rate secured debt was 1.62% as of December 31, 2021. (5) The weighted average interest rate on the Revolving Credit Facility was 1.20% as of December 31, 2021. (6) The interest rate on this loan was 1.10% as of December 31, 2021. (7) The carrying value of these notes reflects an unamortized discount totaling $3.6 million as of December 31, 2021 and $4.5 million as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 2.48%. (8) The carrying value of these notes reflects an unamortized discount totaling $2.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.09%. Refer to paragraph below for further disclosure. (9) The carrying value of these notes reflects an unamortized discount totaling $9.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.94%. Refer to paragraph below for further disclosure. (10) The carrying value of these notes reflects an unamortized discount totaling $4.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 3.01%. Refer to paragraph below for further disclosure. (11) The carrying value of these notes reflects an unamortized discount totaling $781,000 as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 3.70%. Refer to paragraph below for further disclosure. (12) The carrying value of these notes reflects an unamortized discount totaling $1.6 million as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 5.49%. Refer to paragraph below for further disclosure. (13) The carrying value of these notes reflects an unamortized discount totaling $1.8 million as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 5.15%. Refer to paragraph below for further disclosure. (14) This note carries an interest rate that, upon assumption, was below market rates and it therefore was recorded at its fair value based on applicable effective interest rates. The carrying value of this note reflects an unamortized discount totaling $108,000 as of December 31, 2021 and $161,000 as of December 31, 2020. All debt is owed by the Operating Partnership. While COPT is not directly obligated by any debt, it has guaranteed COPLP’s Revolving Credit Facility, Term Loan Facility and Unsecured Senior Notes. Certain of our debt instruments require that we comply with a number of restrictive financial covenants, including maximum leverage ratio, unencumbered leverage ratio, minimum fixed charge coverage ratio, minimum unencumbered interest coverage ratio, minimum debt service and maximum secured indebtedness ratio. In addition, the terms of some of COPLP’s debt may limit its ability to make certain types of payments and other distributions to COPT in the event of default or when such payments or distributions may prompt failure of debt covenants. As of December 31, 2021, we were compliant with these financial covenants. Our debt matures on the following schedule (in thousands): Year Ending December 31, December 31, 2021 2022 $ 303,333 2023 94,953 2024 29,983 2025 23,717 2026 446,300 Thereafter 1,400,000 Total $ 2,298,286 (1) (1) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $26.0 million. We capitalized interest costs of $6.5 million in 2021, $12.1 million in 2020 and $10.8 million in 2019. The following table sets forth information pertaining to the fair value of our debt (in thousands): December 31, 2021 December 31, 2020 Carrying Estimated Carrying Estimated Fixed-rate debt Unsecured Senior Notes $ 1,775,504 $ 1,809,950 $ 1,289,461 $ 1,334,342 Other fixed-rate debt 87,713 87,339 140,891 142,838 Variable-rate debt 409,087 409,639 656,566 654,102 $ 2,272,304 $ 2,306,928 $ 2,086,918 $ 2,131,282 Revolving Credit Facility We have an unsecured revolving credit facility (referred to herein as the “Revolving Credit Facility”) with an aggregate lender commitment of $800.0 million, with the ability for us to increase the lenders’ aggregate commitment to $1.25 billion, provided that there is no default under the facility and subject to the approval of the lenders. The facility matures on March 10, 2023, with the ability for us to further 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 0.075% of the total availability under the facility for each extension period. The interest rate on the facility is based on LIBOR plus 0.775% to 1.450%, as determined by the credit ratings assigned to COPLP by Standard & Poor’s Ratings Services, Moody’s Investors Service, Inc. or Fitch Ratings Ltd. (collectively, the “Ratings Agencies”). The facility also carries a quarterly fee that is based on the lenders’ aggregate commitment under the facility multiplied by a per annum rate of 0.125% to 0.300%, as determined by the credit ratings assigned to COPLP by the Ratings Agencies. As of December 31, 2021, the maximum borrowing capacity under this facility totaled $800.0 million, of which $724.0 million was available. Weighted average borrowings under our Revolving Credit Facility totaled $135.8 million in 2021 and $204.9 million in 2020. The weighted average interest rate on our Revolving Credit Facility was 1.18% in 2021 and 1.55% in 2020. Term Loan Facilities As of December 31, 2021, we had an unsecured term loan facility that carries a variable interest rate based on the LIBOR rate (customarily the 30-day rate) plus 1.00% to 1.65%, as determined by: a ratio of our debt to our assets; and the credit ratings assigned to COPLP by the Ratings Agencies. We amended this loan in 2020 to increase the loan amount by $150.0 million and change the interest terms, and repaid $100.0 million of the loan in 2021. In connection with our Revolving Credit Facility discussed above, we have the ability to borrow up to $500.0 million under new term loans from the facility’s lender group provided that there is no default under the facility and subject to the approval of the lenders. Unsecured Senior Notes During 2020 and 2021, we issued the following unsecured senior notes: • $400.0 million of 2.25% Senior Notes due 2026 (the “2.25% Notes”) at an initial offering price of 99.42% of their face value on September 17, 2020, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $395.3 million. The notes mature on March 15, 2026; • $600.0 million of 2.75% Senior Notes due 2031 (the “2.75% Notes”) at an initial offering price of 98.95% of their face value on March 11, 2021, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $589.8 million. The notes mature on April 15, 2031; • $400.0 million of 2.00% Senior Notes due 2029 (the “2.00% Notes”) at an initial offering price of 99.97% of their face value on August 11, 2021, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $397.4 million. The notes mature on January 15, 2029; and • $400.0 million of 2.90% Senior Notes due 2033 (the “2.90% Notes”) at an initial offering price of 99.53% of their face value on November 17, 2021, resulting in proceeds, after deducting underwriting discounts, but before other offering expenses, of $395.4 million. The notes mature on December 1, 2033. We may redeem our unsecured senior notes, in whole at any time or in part from time to time, at our option, at a redemption price equal to the greater of (1) the aggregate principal amount of the notes being redeemed or (2) the sum of the present values of the remaining scheduled payments of principal and interest thereon (not including any portion of such payments of interest accrued as of the date of redemption) discounted to its present value, on a semi-annual basis at an adjusted treasury rate plus a spread (35 basis points for the 2.25% Notes, 25 basis points for the 2.75% Notes, 20 basis points for the 2.00% Notes and 25 basis points for the 2.90% Notes), plus, in each case, accrued and unpaid interest thereon to the date of redemption. However, in each case, if this redemption occurs on or after a defined date (February 15, 2026 for the 2.25% Notes, January 15, 2031 for the 2.75% Notes, November 15, 2028 for the 2.00% Notes and September 1, 2033 for the 2.90% Notes), the redemption price will be equal to 100% of the principal amount of the notes being redeemed, plus accrued and unpaid interest thereon to, but not including, the applicable redemption date. These notes are unconditionally guaranteed by COPT. During 2020 and 2021, we purchased or redeemed the following unsecured senior notes: • purchased pursuant to a tender offer $122.9 million of our 3.70% Senior Notes due 2021 (the “3.70% Notes”) on September 17, 2020 for $126.0 million, plus accrued interest; and redeemed the remaining $177.1 million of the 3.70% Notes on October 19, 2020 for $180.9 million plus accrued interest. In connection with this purchase and redemption, we recognized a loss on early extinguishment of debt of $7.3 million in 2020; • purchased pursuant to tender offers $184.4 million of 3.60% Senior Notes due 2023 (the “3.60% Notes”) for $196.7 million and $145.6 million of 5.25% Senior Notes due 2024 (the “5.25% Notes”) for $164.7 million, plus accrued interest effective March 11, 2021; and on April 12, 2021, redeemed the remaining $165.6 million of 3.60% Notes for $176.3 million and $104.4 million of 5.25% Notes for $117.7 million, plus accrued interest. In connection with these purchases and redemptions, we recognized a loss on early extinguishment of debt of $58.4 million in 2021; and • redeemed $300.0 million of 5.00% Senior Notes due 2025 on November 18, 2021 for $336.4 million plus accrued interest. We recognized a loss on early extinguishment of debt of $38.2 million for this redemption in 2021.

Interest Rate Derivatives

Interest Rate Derivatives	12 Months Ended
	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Interest Rate Derivatives	Interest Rate Derivatives The following table sets forth the key terms and fair values of our interest rate swap derivatives (dollars in thousands): Notional Amount Effective Date Expiration Date Fair Value at December 31, Fixed Rate Floating Rate Index 2021 2020 $ 100,000 1.901 % One-Month LIBOR 9/1/2016 12/1/2022 $ (1,361) $ (3,394) $ 100,000 1.905 % One-Month LIBOR 9/1/2016 12/1/2022 (1,365) (3,401) $ 50,000 (1) 1.908 % One-Month LIBOR 9/1/2016 12/1/2022 (684) (1,704) $ 11,120 (2) 1.678 % One-Month LIBOR 8/1/2019 8/1/2026 (234) (733) $ 23,000 (3) 0.573 % One-Month LIBOR 4/1/2020 3/26/2025 355 (290) $ (3,289) $ (9,522) (1) Refer to additional disclosure below. (2) The notional amount of this instrument is scheduled to amortize to $10.0 million. (3) 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 except for the swap with a $50.0 million notional amount. We discontinued hedge accounting for this swap effective in December 2021 when we determined that some of its hedged forecasted transactions were probable not to occur due to our entry into a contract to sell our wholesale data center and the debt pay down expected upon completion of the sale. This resulted in our reclassification of $221,000 in losses from AOCL to interest expense in our statement of operations. The table below sets forth the fair value of our interest rate derivatives as well as their classification on our consolidated balance sheets (in thousands): Fair Value at December 31, Derivatives Balance Sheet Location 2021 2020 Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 355 $ — Interest rate swaps designated as cash flow hedges Interest rate derivatives (liabilities) $ (2,960) $ (9,522) Interest rate swap not designated Interest rate derivatives (liabilities) $ (684) $ — The tables below presents the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of Income (Loss) Recognized in AOCL on Derivatives Amount of (Loss) Gain Reclassified from AOCL into Interest Expense on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2021 2020 2019 2021 2020 2019 Interest rate derivatives $ 1,379 $ (39,454) $ (24,321) $ (5,048) $ (3,725) $ 1,415 Amount of Loss Reclassified from AOCL into Loss on Interest Rate Derivatives on Statement of Operations Amount of Loss Recognized on Undesignated Swaps in Loss on Interest Rate Derivatives on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2021 2020 2019 2021 2020 2019 Interest rate derivatives $ — $ (51,865) $ — $ — $ (1,265) $ — As described further in Note 10, in September 2020, we completed our issuance of the 2.25% Notes. In August 2020, in anticipation of pursuing such an issuance, we determined that the forecasted transactions hedged by three interest rate swaps with an effective date of June 30, 2020 and an aggregate notional amount of $225.0 million were no longer probable of occurring, resulting in our discontinuance of hedge accounting on these swaps. When we consummated the note issuance in September 2020, we determined that it was probable that the forecasted transactions would not occur, resulting in our reclassification of $51.9 million in losses from AOCL to loss on interest rate derivatives on our statements of operations. On September 22, 2020, we cash settled these swaps and accrued interest thereon for an aggregate amount of $53.1 million. Based on the fair value of our derivatives as of December 31, 2021, we estimate that approximately $3.4 million of losses will be reclassified from AOCL as an increase to interest expense over the next 12 months. We have agreements with each of our interest rate derivative counterparties that contain provisions under which, if we default or are capable of being declared in default on defined levels of our indebtedness, we could also be declared in default on our derivative obligations. Failure to comply with the loan covenant provisions could result in our being declared in default on any derivative instrument obligations covered by the agreements. As of December 31, 2021, we were not in default with any of these provisions. As of December 31, 2021, the fair value of interest rate derivatives in a liability position related to these agreements was $3.7 million, excluding the effects of accrued interest and credit valuation adjustments. As of December 31, 2021, we had not posted any collateral related to these agreements. If we breach any of these provisions, we could be required to settle our obligations under the agreements at their termination value, which was $4.1 million as of December 31, 2021.

Redeemable Noncontrolling Inter

Redeemable Noncontrolling Interests	12 Months Ended
	Dec. 31, 2021
Noncontrolling Interest [Abstract]
Redeemable Noncontrolling Interests	Redeemable Noncontrolling Interests As discussed further in Note 6, our partners in two real estate joint ventures, LW Redstone Company, LLC and Stevens Investors, LLC, have the right to require us to acquire their respective interests at fair value; accordingly, we classify the fair value of our partners’ interests as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets. The table below sets forth the activity for these redeemable noncontrolling interests (in thousands): For the Years Ended December 31, 2021 2020 2019 Beginning balance $ 25,430 $ 29,431 $ 26,260 Distributions to noncontrolling interests (3,307) (14,034) (2,413) Net income attributable to noncontrolling interests 3,160 3,426 3,835 Adjustment to arrive at fair value of interests 1,615 6,607 1,749 Ending balance $ 26,898 $ 25,430 $ 29,431

Equity

Equity	12 Months Ended
	Dec. 31, 2021
Stockholders' Equity Note [Abstract]
Equity	Equity Preferred Shares As of December 31, 2021, we had 25.0 million preferred shares authorized and unissued at $0.01 par value per share. Common Shares In November 2018, we established an at-the-market (“ATM”) stock offering program under which we may offer and sell common shares in at-the-market stock offerings having an aggregate gross sales price of up to $300.0 million (the “2018 ATM Program”). Under the 2018 ATM Program, we may also, at our discretion, sell common shares under forward equity sales agreements. As of December 31, 2021, we had not issued any shares under the 2018 ATM Program. In 2019, we issued 1.6 million shares for net proceeds of $46.5 million under forward equity sale agreements no longer in effect to issue shares at an initial gross offering price of $31.00 per share, before underwriting discounts, commissions and offering expenses. The forward sale price received upon physical settlement of the agreements was subject to adjustment on a daily basis based on a floating interest rate factor equal to the overnight bank funding rate less a spread, and was decreased on each of certain dates specified in the agreements during the term of the agreements. Certain holders of COPLP common units converted their units into common shares on the basis of one common share for each common unit in the amount of 8,054 in 2021, 14,009 in 2020 and 105,039 in 2019. We declared dividends per common share of $1.10 in 2021, 2020 and 2019. We pay dividends at the discretion of our Board of Trustees. Our ability to pay cash dividends will be dependent upon: (1) the cash flow generated from our operations; (2) cash generated or used by our financing and investing activities; and (3) the annual distribution requirements under the REIT provisions of the Code described in Note 2 and such other factors as the Board of Trustees deems relevant. Our ability to make cash dividends will also be limited by the terms of COPLP’s Partnership Agreement, as well as by limitations imposed by state law. In addition, we are prohibited from paying cash dividends in excess of the amount necessary for us to qualify for taxation as a REIT if a default or event of default exists pursuant to the terms of our Revolving Credit Facility and unsecured term loan; this restriction does not currently limit our ability to pay dividends, and we do not believe that this restriction is reasonably likely to limit our ability to pay future dividends because we expect to comply with the terms of these debt agreements. See Note 14 for disclosure of common share activity pertaining to our share-based compensation plans.

Share-Based Compensation and Ot

Share-Based Compensation and Other Compensation Matters	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Share-Based Compensation and Other Compensation Matters	Share-Based Compensation and Other Compensation Matters Share-Based Compensation Plans In May 2017, we adopted the 2017 Omnibus Equity and Incentive Plan following the approval of such plan by our common shareholders, and we amended the plan in November 2018 (as amended, the “2017 Plan”). We may issue equity-based awards under this plan to officers, employees, non-employee trustees and any other key persons of us and our subsidiaries, as defined in the plan. The plan provides for a maximum of 3.4 million of our common shares to be issued in the form of options, share appreciation rights, restricted share unit awards, restricted share awards, unrestricted share awards, PIUs, dividend equivalent rights and other equity-based awards and for the granting of cash-based awards. This plan expires on May 11, 2027. Shares for the 2017 Plan are issued under a registration statement on Form S-8 that became effective upon filing with the Securities and Exchange Commission. The table below sets forth our reporting for share based compensation cost (in thousands): For the Years Ended December 31, 2021 2020 2019 General, administrative and leasing expenses $ 6,881 $ 5,385 $ 5,748 Property operating expenses 1,098 1,119 966 Capitalized to development activities 719 556 742 Share-based compensation cost $ 8,698 $ 7,060 $ 7,456 The amounts included in our consolidated statements of operations for share-based compensation reflected an estimate of pre-vesting forfeitures of 0% for awards to our executives and non-employee Trustees and 0% to 8% for awards to all other employees. As of December 31, 2021, unrecognized compensation costs related to unvested awards included: • $5.2 million on restricted shares expected to be recognized over a weighted average period of approximately two years; • $3.0 million on performance-based PIUs (“PB-PIUs”) expected to be recognized over a weighted average performance period of approximately two years; • $2.7 million on time-based PIUs (“TB-PIUs”) expected to be recognized over a weighted average period of approximately two years; and • $34,000 on deferred share awards expected to be recognized through May 2022. Restricted Shares The following table summarizes restricted shares under the share-based compensation plans for 2019, 2020 and 2021: Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2018 438,685 $ 28.38 Granted 195,520 $ 26.56 Forfeited (56,341) $ 29.44 Vested (185,001) $ 28.01 Unvested as of December 31, 2019 392,863 $ 27.49 Granted 166,918 $ 25.22 Forfeited (25,773) (1) $ 27.12 Vested (173,191) $ 28.14 Unvested as of December 31, 2020 360,817 $ 26.16 Granted 177,995 $ 26.17 Forfeited (39,664) $ 26.62 Vested (164,575) $ 25.95 Unvested as of December 31, 2021 334,573 $ 26.22 Unvested shares as of December 31, 2021 that are expected to vest 306,658 $ 26.22 (1) Includes 9,064 restricted shares previously awarded to our former Executive Vice President and Chief Operating Officer that were forfeited upon his resignation. Restricted shares granted to employees vest based on increments and over periods of time set forth under the terms of the respective awards provided that the employee remains employed by us. Restricted shares granted to non-employee Trustees vest on the first anniversary of the grant date, provided that the Trustee remains in his or her position. The aggregate intrinsic value of restricted shares that vested was $4.3 million in 2021, $4.4 million in 2020 and $4.9 million in 2019. PIUs We granted two forms of PIUs: TB-PIUs; and PB-PIUs. TB-PIUs are subject to forfeiture restrictions until the end of the requisite service period, at which time the TB-PIUs automatically convert into vested PIUs. PB-PIUs are subject to a market condition in that the number of earned awards are determined at the end of the performance period (as described further below) and then settled in vested PIUs. Vested PIUs carry substantially the same rights to redemption and distributions as non-PIU common units. TB-PIUs TB-PIUs granted to senior management team members vest based on increments and over periods of time set forth under the terms of the respective awards provided that the employee remains employed by us. TB-PIUs granted to non-employee Trustees vest on the first anniversary of the grant date, provided that the Trustee remains in his or her position. Prior to vesting, TB-PIUs carry substantially the same rights to distributions as non-PIU common units but carry no redemption rights. The following table summarizes TB-PIUs under the share-based compensation plan for 2019, 2020 and 2021 : Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2018 — N/A Granted 61,820 $ 26.01 Unvested as of December 31, 2019 61,820 $ 26.01 Granted 98,318 $ 25.47 Forfeited (20,622) (1) $ 25.50 Vested (25,182) $ 26.30 Unvested as of December 31, 2020 114,334 $ 25.57 Granted 93,983 $ 26.16 Vested (45,244) $ 25.28 Unvested as of December 31, 2021 163,073 $ 25.99 Unvested TB-PIUs as of December 31, 2021 that are expected to vest 162,472 $ 25.99 (1) Represents TB-PIUs previously awarded to our former Executive Vice President and Chief Operating Officer that were forfeited upon his resignation. The aggregate intrinsic value of TB-PIUs that vested was $1.2 million in 2021 and $640,000 in 2020. PB-PIUs We made the following grants of PB-PIUs to executives in 2019, 2020 and 2021 (dollars in thousands, except per share data): Grant Date Number of PB-PIUs Granted Grant Date Fair Value Number of PB-PIUs Outstanding as of December 31, 2021 (1) 1/1/2019 193,682 $ 2,415 156,104 1/1/2020 176,758 $ 2,891 141,152 1/1/2021 227,544 $ 3,417 227,544 (1) Excludes 73,184 PB-PIUs previously awarded to our former Executive Vice President and Chief Operating Officer that were forfeited upon his resignation. The PB-PIUs each have a three-year performance period concluding on the earlier of the respective performance period end dates, or the date of: (1) termination by us without cause, death or disability of the executive or constructive discharge of the executive (collectively, “qualified termination”); or (2) a sale event. The number of earned awards at the end of the performance period will be determined based on the percentile rank of COPT’s total shareholder return (“TSR”) relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned Awards Payout % 75th or greater 100% of PB-PIUs granted 50th (target) 50% of PB-PIUs granted 25th 25% of PB-PIUs granted Below 25th 0% of PB-PIUs granted If the percentile rank exceeds the 25th percentile and is between two of the percentile ranks set forth in the table above, then the percentage of the earned awards will be interpolated between the ranges set forth in the table above to reflect any performance between the listed percentiles. If COPT’s TSR during the measurement period is negative, the maximum number of earned awards will be limited to the target level payout percentage. During the performance period, PB-PIUs carry rights to distributions equal to 10% of the distribution rights of non-PIU common units but carry no redemption rights. At the end of the performance period, we will settle the award by issuing vested PIUs equal to the number of earned awards and either: • for awards granted January 1, 2019 and 2020, paying cash equal to the excess, if any, of: the aggregate distributions that would have been paid with respect to vested PIUs issued in settlement of the earned awards through the date of settlement had such vested PIUs been issued on the grant date; over the aggregate distributions made on the PB-PIUs during the performance period; or • for awards granted January 1, 2021, issuing additional vested PIUs equal to the excess, if any, of (1) the aggregate distributions that would have been paid with respect to vested PIUs issued in settlement of the earned awards through the date of settlement had such vested PIUs been issued on the grant date over (2) the aggregate distributions made on the PB-PIUs during the performance period, divided by the price of our common shares on the settlement date. If a performance period ends due to a sale event or qualified termination, the number of earned awards is prorated based on the portion of the three-year performance period that has elapsed. If employment is terminated by the employee or by us for cause, all PB-PIUs are forfeited. Based on COPT’s TSR relative to its peer group of companies, for the 2019 PB-PIUs issued to executives that vested on December 31, 2021, we issued 156,104 PIUs in settlement of the PB-PIUs on February 1, 2022. We computed grant date fair values for PB-PIUs using Monte Carlo models and are recognizing these values over the respective performance periods. The grant date fair value and certain of the assumptions used in the Monte Carlo models for the PB-PIUs granted in 2019, 2020 and 2021 are set forth below: Grant Date Grant Date Fair Value Per PB-PIU at Target-Level Award Baseline Common Share Value Expected Volatility of Common Shares Risk-free Interest Rate 1/1/2019 $ 24.94 $ 21.03 21.0 % 2.51 % 1/1/2020 $ 32.71 $ 29.38 18.0 % 1.65 % 1/1/2021 $ 30.03 $ 26.08 34.7 % 0.18 % PSUs As of December 31, 2021, we had no PSU grants outstanding. Below is information for executive grants of PSUs with performance periods included in these consolidated financial statements (dollars in thousands): Grant Date Number of PSUs Granted Grant Date Fair Value 1/1/2017 39,351 $ 1,415 1/1/2018 59,110 $ 1,890 The PSUs each had three-year performance periods concluding on the earlier of the respective performance period end dates or the date of: (1) termination by us without cause, death or disability of the executive or constructive discharge of the executive (collectively, “qualified termination”); or (2) a sale event. The number of PSUs earned (“earned PSUs”) at the end of the performance period were determined based on the percentile rank of COPT’s TSR relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned PSUs Payout % 75th or greater 200% of PSUs granted 50th (target) 100% of PSUs granted 25th 50% of PSUs granted Below 25th 0% of PSUs granted If the percentile rank exceeded the 25th percentile and was between two of the percentile ranks set forth in the table above, then the percentage of the earned PSUs was interpolated between the ranges set forth in the table above to reflect any performance between the listed percentiles. At the end of the performance period, we settled the award by issuing fully-vested COPT shares equal to the number of earned PSUs in settlement of the award plan and either: • for awards granted January 1, 2017, issuing fully-vested COPT shares equal to the aggregate dividends that would have been paid with respect to the common shares issued in settlement of the earned PSUs through the date of settlement had such shares been issued on the grant date, divided by the share price on the settlement date; or • for awards granted January 1, 2018, paying cash equal to the aggregate dividends that would have been paid with respect to the common shares issued in settlement of the earned PSUs through the date of settlement had such shares been issued on the grant date. If employment was terminated by the employee or by us for cause, all PSUs were forfeited. PSUs do not carry voting rights. Based on COPT’s TSR relative to its peer group of companies: • for the 2017 PSUs that vested on December 31, 2019, we issued 23,181 common shares in settlement of the PSUs on January 13, 2020; and • for the 2018 PSUs that vested on December 31, 2020, we issued 93,824 common shares in settlement of the PSUs on February 3, 2021. We computed grant date fair values for PSUs using Monte Carlo models and recognized these values over the performance periods. Deferred Share Awards We made the following grants of deferred share awards to non-employee Trustees in 2019, 2020 and 2021 (dollars in thousands, except per share data): Year of Grant Number of Deferred Share Awards Granted Aggregate Grant Date Fair Value Grant Date Fair Value Per Award 2019 3,432 $ 95 $ 27.60 2020 10,679 $ 253 $ 23.68 2021 3,416 $ 93 $ 27.12 Deferred share awards vest on the first anniversary of the grant date, provided that the Trustee remains in his or her position. We settle deferred share awards by issuing an equivalent number of common shares upon vesting of the awards or a later date elected by the Trustee (generally upon cessation of being a Trustee). We issued 3,097 common shares with a grant date fair value of $26.77 per award and an aggregate intrinsic value of $86,000 in settlement of deferred shares in 2019 (no award settlements occurred in 2020 or 2021).

Credit Losses, Financial Assets

Credit Losses, Financial Assets and Other Instruments	12 Months Ended
	Dec. 31, 2021
Credit Loss [Abstract]
Credit Losses, Financial Assets and Other Instruments	Credit Losses, Financial Assets and Other Instruments The table below sets forth the activity for the allowance for credit losses (in thousands): For the Years Ended December 31, 2020 and 2021 Investing Receivables Tenant Notes Other Assets (2) Off-Balance Sheet Credit Exposures Total December 31, 2019 $ — $ 97 $ — $ — $ 97 Cumulative effect of change for adoption of credit loss guidance 3,732 325 144 1,340 5,541 Credit loss (recoveries) expense (881) 729 559 (1,340) (933) Other changes — 52 (60) — (8) December 31, 2020 2,851 1,203 643 — 4,697 Credit loss (recoveries) expense (1,252) (146) 270 — (1,128) December 31, 2021 $ 1,599 $ 1,057 $ 913 $ — $ 3,569 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of December 31, 2021 and December 31, 2020 included $218,000 and $257,000, respectively, in the line entitled “accounts receivable, net” and $695,000 and $386,000, respectively, in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets. The following table presents the amortized cost basis of our investing receivables, tenants notes receivable and sales-type lease receivables by credit risk classification, by origination year as of December 31, 2021 (in thousands): Origination Year 2016 and Earlier 2017 2018 2019 2020 2021 Total Investing receivables: Credit risk classification: Investment grade $ 70,434 $ 1,069 $ — $ — $ 1,675 $ 4,606 $ 77,784 Non-investment grade — — — 6,041 — — 6,041 Total $ 70,434 $ 1,069 $ — $ 6,041 $ 1,675 $ 4,606 $ 83,825 Tenant notes receivable: Credit risk classification: Investment grade $ — $ — $ 921 $ 63 $ 271 $ — $ 1,255 Non-investment grade 207 — 132 137 1,724 — 2,200 Total $ 207 $ — $ 1,053 $ 200 $ 1,995 $ — $ 3,455 Sales-type lease receivable: Credit risk classification: Investment grade $ — $ — $ — $ — $ 6,194 $ — $ 6,194 Our investment grade credit risk classification represents entities with investment grade credit ratings from ratings agencies (such as Standard & Poor’s Ratings Services, Moody’s Investors Service, Inc. or Fitch Ratings Ltd.), meaning that they are considered to have at least an adequate capacity to meet their financial commitments, with credit risk ranging from minimal to moderate. Our non-investment grade credit risk classification represents entities with either no credit agency credit ratings or ratings deemed to be sub-investment grade; we believe that there is significantly more credit risk associated with this classification. The credit risk classifications of our investing receivables and tenant notes receivable were last updated in December 2021. An insignificant portion of the investing and tenant notes receivables set forth above was past due, which we define as being delinquent by more than three months from the due date. Notes receivable on nonaccrual status as of December 31, 2021 and 2020 were not significant. We did not recognize any interest income on notes receivable on nonaccrual status during the years ended December 31, 2021 and 2020.

Information by Business Segment

Information by Business Segment	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Information by Business Segment	Information by Business SegmentWe have the following reportable segments: Defense/IT Locations; Regional Office; Wholesale Data Center; and Other. We also report on Defense/IT Locations sub-segments, which include the following: Fort George G. Meade and the Baltimore/Washington Corridor (“Fort Meade/BW Corridor”); NoVA Defense/IT; Lackland Air Force Base (in San Antonio); locations serving the U.S. Navy (“Navy Support”), which included properties proximate to the Washington Navy Yard, the Naval Air Station Patuxent River in Maryland and the Naval Surface Warfare Center Dahlgren Division in Virginia; Redstone Arsenal (in Huntsville); and data center shells (properties leased to tenants to be operated as data centers in which the tenants fund the costs for the power, fiber connectivity and data center infrastructure). In 2021, we retrospectively classified certain activities with our Other reportable segment that were previously classified with our Wholesale Data Center reportable segment.We measure the performance of our segments through the measure we define as net operating income from real estate operations (“NOI from real estate operations”), which includes: real estate revenues and property operating expenses; and the net of revenues and property operating expenses of real estate operations owned through unconsolidated real estate joint ventures (“UJVs”) that is allocable to our ownership interest (“UJV NOI allocable to COPT”). Amounts reported for segment assets represent long-lived assets associated with consolidated operating properties (including the carrying value of properties, right-of-use assets, net of related lease liabilities, intangible assets, deferred leasing costs, deferred rents receivable and lease incentives) and the carrying value of investments in UJVs owning operating properties. Amounts reported as additions to long-lived assets represent additions to existing consolidated operating properties, excluding transfers from non-operating properties, which we report separately. The table below reports segment financial information for our reportable segments (in thousands): Defense/IT Locations Fort Meade/BW Corridor NoVA Defense/IT Lackland Air Force Base Navy Support Redstone Arsenal Data Center Shells Total Defense/IT Locations Regional Office Wholesale Other Total Year Ended December 31, 2021 Revenues from real estate operations $ 262,120 $ 62,390 $ 57,756 $ 33,757 $ 35,727 $ 31,582 $ 483,332 $ 66,570 $ 30,490 $ 6,668 $ 587,060 Property operating expenses (92,521) (23,218) (30,535) (13,617) (11,618) (4,086) (175,595) (32,623) (17,424) (4,577) (230,219) UJV NOI allocable to COPT — — — — — 4,029 4,029 — — — 4,029 NOI from real estate operations $ 169,599 $ 39,172 $ 27,221 $ 20,140 $ 24,109 $ 31,525 $ 311,766 $ 33,947 $ 13,066 $ 2,091 $ 360,870 Additions to long-lived assets $ 45,647 $ 5,823 $ — $ 4,193 $ 3,542 $ — $ 59,205 $ 35,412 $ 1,680 $ 488 $ 96,785 Transfers from non-operating properties $ 70,514 $ 90,050 $ 59,323 $ — $ 22,739 $ 3,004 $ 245,630 $ 39,319 $ — $ — $ 284,949 Segment assets at December 31, 2021 $ 1,332,399 $ 471,760 $ 198,200 $ 170,985 $ 300,252 $ 350,098 $ 2,823,694 $ 555,090 $ 192,647 $ 4,031 $ 3,575,462 Year Ended December 31, 2020 Revenues from real estate operations $ 254,197 $ 57,817 $ 50,982 $ 32,869 $ 22,515 $ 29,139 $ 447,519 $ 60,627 $ 27,011 $ 3,568 $ 538,725 Property operating expenses (85,032) (21,321) (29,055) (12,655) (8,119) (3,195) (159,377) (29,144) (13,543) (1,776) (203,840) UJV NOI allocable to COPT — — — — — 6,951 6,951 — — — 6,951 NOI from real estate operations $ 169,165 $ 36,496 $ 21,927 $ 20,214 $ 14,396 $ 32,895 $ 295,093 $ 31,483 $ 13,468 $ 1,792 $ 341,836 Additions to long-lived assets $ 31,295 $ 11,620 $ — $ 7,104 $ 2,905 $ — $ 52,924 $ 17,232 $ 10,856 $ 467 $ 81,479 Transfers from non-operating properties $ 21,859 $ 2,557 $ 456 $ — $ 138,122 $ 230,277 $ 393,271 $ 83,091 $ — $ — $ 476,362 Segment assets at December 31, 2020 $ 1,277,849 $ 392,714 $ 142,137 $ 178,897 $ 281,386 $ 419,929 $ 2,692,912 $ 490,422 $ 201,820 $ 3,824 $ 3,388,978 Year Ended December 31, 2019 Revenues from real estate operations $ 252,781 $ 55,742 $ 51,140 $ 32,659 $ 16,593 $ 26,571 $ 435,486 $ 59,611 $ 29,405 $ 2,961 $ 527,463 Property operating expenses (82,815) (19,779) (29,042) (13,579) (6,626) (1,962) (153,803) (29,682) (13,213) (1,445) (198,143) UJV NOI allocable to COPT — — — — — 5,705 5,705 — — — 5,705 NOI from real estate operations $ 169,966 $ 35,963 $ 22,098 $ 19,080 $ 9,967 $ 30,314 $ 287,388 $ 29,929 $ 16,192 $ 1,516 $ 335,025 Additions to long-lived assets $ 34,618 $ 9,326 $ — $ 8,912 $ 1,548 $ — $ 54,404 $ 20,925 $ 893 $ 128 $ 76,350 Transfers from non-operating properties $ 18,606 $ 4,548 $ 10,781 $ — $ 33,606 $ 159,472 $ 227,013 $ — $ (1,012) $ — $ 226,001 Segment assets at December 31, 2019 $ 1,280,656 $ 396,914 $ 146,592 $ 184,257 $ 138,501 $ 279,099 $ 2,426,019 $ 392,319 $ 202,935 $ 3,685 $ 3,024,958 The following table reconciles our segment revenues to total revenues as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 Segment revenues from real estate operations $ 587,060 $ 538,725 $ 527,463 Construction contract and other service revenues 107,876 70,640 113,763 Less: Revenues from discontinued operations (Note 4) (30,490) (27,011) (29,405) Total revenues $ 664,446 $ 582,354 $ 611,821 The following table reconciles our segment property operating expenses to property operating expenses as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 Segment property operating expenses $ 230,219 $ 203,840 $ 198,143 Less: Property operating expenses from discontinued operations (Note 4) (16,842) (13,044) (12,694) Total property operating expenses $ 213,377 $ 190,796 $ 185,449 The following table reconciles UJV NOI allocable to COPT to equity in income of unconsolidated entities as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 UJV NOI allocable to COPT $ 4,029 $ 6,951 $ 5,705 Less: Income from UJVs allocable to COPT attributable to depreciation and amortization expense and interest expense (2,930) (5,120) (4,065) Add: Equity in loss of unconsolidated non-real estate entities (6) (6) (7) Equity in income of unconsolidated entities $ 1,093 $ 1,825 $ 1,633 As previously discussed, we provide real estate services such as property management, development and construction services primarily for our properties but also for third parties. The primary manner in which we evaluate the operating performance of our service activities is through a measure we define as net operating income from service operations (“NOI from service operations”), which is based on the net of revenues and expenses from these activities. Construction contract and other service revenues and expenses consist primarily of subcontracted costs that are reimbursed to us by the customer along with a management fee. The operating margins from these activities are small relative to the revenue. We believe NOI from service operations is a useful measure in assessing both our level of activity and our profitability in conducting such operations. The table below sets forth the computation of our NOI from service operations (in thousands): For the Years Ended December 31, 2021 2020 2019 Construction contract and other service revenues $ 107,876 $ 70,640 $ 113,763 Construction contract and other service expenses (104,053) (67,615) (109,962) NOI from service operations $ 3,823 $ 3,025 $ 3,801 The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to income from continuing operations as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 NOI from real estate operations $ 360,870 $ 341,836 $ 335,025 NOI from service operations 3,823 3,025 3,801 Interest and other income 7,879 8,574 7,894 Credit loss recoveries 1,128 933 — Gain on sales of real estate 65,590 30,209 105,230 Gain on sale of investment in unconsolidated real estate joint venture — 29,416 — Equity in income of unconsolidated entities 1,093 1,825 1,633 Income tax (expense) benefit (145) (353) 217 Depreciation and other amortization associated with real estate operations (137,543) (126,503) (125,008) Impairment losses — (1,530) (329) General, administrative and leasing expenses (36,127) (33,001) (35,402) Business development expenses and land carry costs (4,647) (4,473) (4,239) Interest expense (65,398) (67,937) (71,052) UJV NOI allocable to COPT included in equity in income of unconsolidated entities (4,029) (6,951) (5,705) Revenues from real estate operations from discontinued operations (Note 4) (30,490) (27,011) (29,405) Property operating expenses from discontinued operations (Note 4) 16,842 13,044 12,694 Loss on early extinguishment of debt (100,626) (7,306) — Loss on interest rate derivatives — (53,196) — Income from continuing operations $ 78,220 $ 100,601 $ 195,354 The following table reconciles our segment assets to our consolidated total assets (in thousands): As of December 31, 2021 2020 Segment assets $ 3,575,462 $ 3,388,978 Operating properties lease liabilities included in segment assets 29,342 30,721 Non-operating property assets 449,144 466,991 Other assets 208,504 190,333 Total consolidated assets $ 4,262,452 $ 4,077,023 The accounting policies of the segments are the same as those used to prepare our consolidated financial statements, except that discontinued operations are not presented separately for segment purposes. In the segment reporting presented above, we did not allocate interest expense, depreciation and amortization, impairment losses, gain on sales of real estate, gain on sale of investment in unconsolidated real estate joint venture, loss on early extinguishment of debt, loss on interest rate derivatives and equity in income of unconsolidated entities not included in NOI to our real estate segments since they are not included in the measure of segment profit reviewed by management. We also did not allocate general, administrative and leasing expenses, business development expenses and land carry costs, interest and other income, credit loss recoveries, income taxes and noncontrolling interests because these items represent general corporate or non-operating property items not attributable to segments.

Construction Contract and Other

Construction Contract and Other Service Revenues	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Construction Contract and Other Service Revenues	Construction Contract and Other Service Revenues We disaggregate our construction contract and other service revenues by compensation arrangement and by service type as we believe it best depicts the nature, timing and uncertainty of our revenue. The table below reports construction contract and other service revenues by compensation arrangement (in thousands): For the Years Ended December 31, 2021 2020 2019 Construction contract revenue: GMP $ 68,113 $ 22,032 $ 67,708 Cost-plus fee 24,260 34,025 34,386 FFP 13,897 12,373 10,688 Other 1,606 2,210 981 $ 107,876 $ 70,640 $ 113,763 The table below reports construction contract and other service revenues by service type (in thousands): For the Years Ended December 31, 2021 2020 2019 Construction contract revenue: Construction $ 104,020 $ 66,087 $ 112,170 Design 2,250 2,343 612 Other 1,606 2,210 981 $ 107,876 $ 70,640 $ 113,763 We derived 79% of our construction contract revenue from the USG in 2021, 55% in 2020 and 74% in 2019. We recognized an insignificant amount of revenue in 2021, 2020 and 2019 from performance obligations satisfied (or partially satisfied) in previous periods. Accounts receivable related to our construction contract services is included in accounts receivable, net on our consolidated balance sheets. The beginning and ending balances of accounts receivable related to our construction contracts were as follows (in thousands): For the Years Ended December 31, 2021 2020 Beginning balance $ 13,997 $ 12,378 Ending balance $ 7,193 $ 13,997 Contract assets, which we refer to herein as construction contract costs in excess of billings, net, are included in prepaid expenses and other assets, net on our consolidated balance sheets. The beginning and ending balances of our contract assets were as follows (in thousands): For the Years Ended December 31, 2021 2020 Beginning balance $ 10,343 $ 17,223 Ending balance $ 22,384 $ 10,343 Contract liabilities are included in other liabilities on our consolidated balance sheets. Changes in contract liabilities were as follows (in thousands): For the Years Ended December 31, 2021 2020 Beginning balance $ 4,610 $ 1,184 Ending balance $ 2,499 $ 4,610 Portion of beginning balance recognized in revenue during the year $ 2,664 $ 757 Revenue allocated to the remaining performance obligations under existing contracts as of December 31, 2021 that will be recognized as revenue in future periods was $147.8 million, of which we expect to recognize approximately $98 million in 2022.

Earnings Per Share ("EPS")

Earnings Per Share ("EPS")	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Earnings Per Share ("EPS")	Earnings Per Share (“EPS”) We present both basic and diluted EPS. We compute basic EPS by dividing net income available to common shareholders allocable to unrestricted common shares under the two-class method by the weighted average number of unrestricted common shares outstanding during the period. Our computation of diluted EPS is similar except that: • the denominator is increased to include: (1) the weighted average number of potential additional common shares that would have been outstanding if securities that are convertible into common shares were converted; and (2) the effect of dilutive potential common shares outstanding during the period attributable to redeemable noncontrolling interests, share-based compensation awards and forward equity sale agreements using the if-converted or treasury stock methods; and • the numerator is adjusted to add back any changes in income or loss that would result from the assumed conversion into common shares that we add to the denominator. Summaries of the numerator and denominator for purposes of basic and diluted EPS calculations are set forth below (in thousands, except per share data): For the Years Ended December 31, 2021 2020 2019 Numerator: Income from continuing operations $ 78,220 $ 100,601 $ 195,354 Income from continuing operations attributable to noncontrolling interests (4,994) (5,477) (8,255) Income from continuing operations attributable to share-based compensation awards for basic EPS (467) (433) (638) Numerator for basic EPS from continuing operations attributable to COPT common shareholders $ 72,759 $ 94,691 $ 186,461 Redeemable noncontrolling interests (128) — 132 Adjustment to income from continuing operations attributable to share-based compensation awards for diluted EPS 44 27 33 Numerator for diluted EPS from continuing operations attributable to COPT common shareholders $ 72,675 $ 94,718 $ 186,626 Discontinued operations 3,358 2,277 4,650 Discontinued operations attributable to noncontrolling interests (43) (27) (57) Income from discontinued operations attributable to share-based compensation awards for diluted EPS 6 2 (18) Numerator for diluted EPS on net income attributable to COPT common shareholders $ 75,996 $ 96,970 $ 191,201 Denominator (all weighted averages): Denominator for basic EPS (common shares) 111,960 111,788 111,196 Dilutive effect of redeemable noncontrolling interests 128 — 119 Dilutive effect of share-based compensation awards 330 288 308 Denominator for diluted EPS (common shares) 112,418 112,076 111,623 Basic EPS: Income from continuing operations attributable to COPT common shareholders $ 0.65 $ 0.85 $ 1.68 Discontinued operations attributable to COPT common shareholders 0.03 0.02 0.04 Net income attributable to COPT common shareholders $ 0.68 $ 0.87 $ 1.72 Diluted EPS: Income from continuing operations attributable to COPT common shareholders $ 0.65 $ 0.85 $ 1.67 Discontinued operations attributable to COPT common shareholders 0.03 0.02 0.04 Net income attributable to COPT common shareholders $ 0.68 $ 0.87 $ 1.71 Our diluted EPS computations do not include the effects of the following securities since the conversions of such securities would increase diluted EPS for the respective periods (in thousands): Weighted Average Shares Excluded from Denominator for the Years Ended December 31, 2021 2020 2019 Conversion of common units 1,257 1,236 1,299 Conversion of redeemable noncontrolling interests 804 957 896 Conversion of Series I Preferred Units — 171 176 The following securities were also excluded from the computation of diluted EPS because their effect was antidilutive: • weighted average restricted shares and deferred share awards of 412,000 for 2021, 430,000 for 2020 and 441,000 for 2019; • weighted average TB-PIUs of 158,000 for 2021, 89,000 for 2020 and 51,000 for 2019; • weighted average options of 12,000 for 2019; and • weighted average shares related to forward equity sale agreements of 376,000 for 2019.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Litigation and Claims In the normal course of business, we are subject to legal actions and other claims. We record losses for specific legal proceedings and claims when we determine that a loss is probable and the amount of loss can be reasonably estimated. As of December 31, 2021, management believes that it is reasonably possible that we could recognize a loss of up to $3.6 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 operation. 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 much 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 $31 million as of December 31, 2021. The real estate taxes on increases in assessed values post-bond issuance of properties in development districts encompassing the National Business Park are transferred to a special fund pledged to the repayment of the bonds. While we are obligated to fund, through a special tax, any future shortfalls between debt service of the bonds and real estate taxes available to repay the bonds, as of December 31, 2021, we do not expect any such future fundings will be required. Effects of COVID-19 As of the date of this filing, spread of COVID-19 continues world- and nation-wide. Since the beginning of 2021, the United States has significantly increased the proportion of the population that has received COVID-19 vaccines, and there is increased confidence that spread of COVID-19 can, to a large extent, be contained through vaccinations and wearing masks indoors in public. As a result, most restrictive measures previously instituted by governments and other authorities to control spread have been gradually lifted and an increased proportion of the population has resumed a return to normal activities. However, there continues to be significant uncertainty regarding the duration and extent of the pandemic due to factors such as the continuing spread of the virus, the pace of world- and nation-wide vaccination efforts, the continued emergence of new variants of the virus and the efficacy of vaccines against such variants. While the pandemic has impacted the operations of much of the commercial real estate industry, we believe that we have been less susceptible to such impact due to our portfolio’s significant concentration in Defense/IT Locations. As a result, we believe that we have not been significantly affected by the pandemic. COVID-19, along with measures instituted to prevent spread, may adversely affect us in many ways, including, but not limited to: • disruption of our tenants’ operations, which could adversely affect their ability, or willingness, to sustain their businesses and/or fulfill their lease obligations; • our ability to maintain occupancy in our properties and obtain new leases for unoccupied and new development space at favorable terms or at all; • shortages in supply of products or services from our and our tenants’ vendors that are needed for us and our tenants to operate effectively, and which could lead to increased costs for such products and services; • access to debt and equity capital on attractive terms or at all. Severe disruption and instability in the global financial markets or deteriorations in credit and financing conditions may affect our or our tenants’ ability to access capital necessary to fund operations, refinance debt or fund planned investments on a timely basis, and may adversely affect the valuation of financial assets and liabilities; • our and our tenants’ ability to continue or complete planned development, including the potential for delays in the supply of materials or labor necessary for development; and • an increase in the pace of businesses implementing remote work arrangements over the long-term, which would adversely effect demand for office space.

Quarterly Data (Unaudited)

Quarterly Data (Unaudited)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Quarterly Data (Unaudited)	Quarterly Data (Unaudited) The tables below set forth selected quarterly information for the years ended December 31, 2021 and 2020 (in thousands, except per share/unit data). 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, including amounts reclassified in conjunction with the transfer of our wholesale data center to discontinued operations in December 2021. For the Year Ended December 31, 2021 For the Year Ended December 31, 2020 First Quarter Second Quarter Third Quarter Fourth Quarter First Quarter Second Quarter Third Quarter Fourth Quarter Revenues $ 154,388 $ 157,207 $ 166,919 $ 185,932 $ 138,625 $ 138,321 $ 148,801 $ 156,607 (Loss) income from continuing operations $ (6,894) $ 43,219 $ 28,343 $ 13,552 $ 24,426 $ 24,984 $ (30,991) $ 82,182 Discontinued operations 815 679 451 1,413 1,124 137 (351) 1,367 Net (loss) income $ (6,079) $ 43,898 $ 28,794 $ 14,965 $ 25,550 $ 25,121 $ (31,342) $ 83,549 Net loss (income) attributable noncontrolling interests (590) (1,497) (1,693) (1,257) (1,496) (1,624) (503) (1,881) Net (loss) income attributable to COPT common shareholders $ (6,669) $ 42,401 $ 27,101 $ 13,708 $ 24,054 $ 23,497 $ (31,845) $ 81,668 Basic EPS $ (0.06) $ 0.38 $ 0.24 $ 0.12 $ 0.21 $ 0.21 $ (0.29) $ 0.73 Diluted EPS $ (0.06) $ 0.38 $ 0.24 $ 0.12 $ 0.21 $ 0.21 $ (0.29) $ 0.73

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2021
Subsequent Events [Abstract]
Subsequent Events	Subsequent EventOn January 25, 2022, we sold 9651 Hornbaker Road in Manassas, Virginia, our wholesale data center, for $222.5 million, resulting in a gain on sale of approximately $29 million.

Schedule III - Real Estate and

Schedule III - Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2021
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III-Real Estate and Accumulated Depreciation	Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 100 Light Street (O) Baltimore, MD $ — $ 26,715 $ 58,002 $ 36,662 $ 26,715 $ 94,664 $ 121,379 $ (25,616) 1973/2011 8/7/2015 100 Secured Gateway (O) Huntsville, AL — — 71,089 — — 71,089 71,089 (2,340) 2020 3/23/2010 1000 Redstone Gateway (O) Huntsville, AL 9,281 — 20,533 76 — 20,609 20,609 (4,525) 2013 3/23/2010 1100 Redstone Gateway (O) Huntsville, AL 9,913 — 19,593 88 — 19,681 19,681 (3,912) 2014 3/23/2010 114 National Business Parkway (O) Annapolis Junction, MD — 364 3,109 404 364 3,513 3,877 (1,679) 2002 6/30/2000 1200 Redstone Gateway (O) Huntsville, AL 11,441 — 22,389 141 — 22,530 22,530 (4,509) 2013 3/23/2010 1201 M Street SE (O) Washington, DC — — 49,775 10,290 — 60,065 60,065 (21,051) 2001 9/28/2010 1201 Winterson Road (O) Linthicum, MD — 2,130 17,009 901 2,130 17,910 20,040 (5,952) 1985/2017 4/30/1998 1220 12th Street SE (O) Washington, DC — — 42,464 9,749 — 52,213 52,213 (19,797) 2003 9/28/2010 1243 Winterson Road (L) Linthicum, MD — 630 — — 630 — 630 — (6) 12/19/2001 131 National Business Parkway (O) Annapolis Junction, MD — 1,906 7,623 5,893 1,906 13,516 15,422 (7,872) 1990 9/28/1998 132 National Business Parkway (O) Annapolis Junction, MD — 2,917 12,259 4,876 2,917 17,135 20,052 (11,075) 2000 5/28/1999 133 National Business Parkway (O) Annapolis Junction, MD — 2,517 10,068 6,731 2,517 16,799 19,316 (10,935) 1997 9/28/1998 134 National Business Parkway (O) Annapolis Junction, MD — 3,684 7,517 5,726 3,684 13,243 16,927 (8,014) 1999 11/13/1998 1340 Ashton Road (O) Hanover, MD — 905 3,620 2,540 905 6,160 7,065 (3,423) 1989 4/28/1999 13450 Sunrise Valley Drive (O) Herndon, VA — 1,386 5,576 4,952 1,386 10,528 11,914 (6,583) 1998 7/25/2003 13454 Sunrise Valley Drive (O) Herndon, VA — 2,847 11,986 9,240 2,847 21,226 24,073 (12,918) 1998 7/25/2003 135 National Business Parkway (O) Annapolis Junction, MD — 2,484 9,750 7,003 2,484 16,753 19,237 (10,779) 1998 12/30/1998 1362 Mellon Road (O) Hanover, MD — 950 3,864 1,632 950 5,496 6,446 (1,193) 2006 2/10/2006 13857 McLearen Road (O) Herndon, VA — 3,507 30,177 4,915 3,507 35,092 38,599 (13,842) 2007 7/11/2012 140 National Business Parkway (O) Annapolis Junction, MD — 3,407 24,167 1,784 3,407 25,951 29,358 (11,646) 2003 12/31/2003 141 National Business Parkway (O) Annapolis Junction, MD — 2,398 9,538 4,832 2,398 14,370 16,768 (9,758) 1990 9/28/1998 14280 Park Meadow Drive (O) Chantilly, VA — 3,731 15,953 5,500 3,731 21,453 25,184 (10,469) 1999 9/29/2004 1460 Dorsey Road (L) Hanover, MD — 1,577 115 — 1,577 115 1,692 — (6) 2/28/2006 14840 Conference Center Drive (O) Chantilly, VA — 1,572 8,175 5,730 1,572 13,905 15,477 (7,895) 2000 7/25/2003 14850 Conference Center Drive (O) Chantilly, VA — 1,615 8,358 5,345 1,615 13,703 15,318 (7,455) 2000 7/25/2003 14900 Conference Center Drive (O) Chantilly, VA — 3,436 14,402 9,282 3,436 23,684 27,120 (14,024) 1999 7/25/2003 1501 South Clinton Street (O) Baltimore, MD — 27,964 51,990 23,731 27,964 75,721 103,685 (31,475) 2006 10/27/2009 15049 Conference Center Drive (O) Chantilly, VA — 4,415 20,365 17,846 4,415 38,211 42,626 (20,360) 1997 8/14/2002 15059 Conference Center Drive (O) Chantilly, VA — 5,753 13,615 4,543 5,753 18,158 23,911 (10,774) 2000 8/14/2002 1550 West Nursery Road (O) Linthicum, MD — 14,071 16,930 — 14,071 16,930 31,001 (6,678) 2009 10/28/2009 1560 West Nursery Road (O) Linthicum, MD — 1,441 113 — 1,441 113 1,554 (22) 2014 10/28/2009 1610 West Nursery Road (O) Linthicum, MD — 259 246 — 259 246 505 (29) 2016 4/30/1998 1616 West Nursery Road (O) Linthicum, MD — 393 3,323 75 393 3,398 3,791 (358) 2017 4/30/1998 1622 West Nursery Road (O) Linthicum, MD — 393 2,542 — 393 2,542 2,935 (308) 2016 4/30/1998 16442 Commerce Drive (O) Dahlgren, VA — 613 2,582 1,135 613 3,717 4,330 (1,988) 2002 12/21/2004 16480 Commerce Drive (O) Dahlgren, VA — 1,856 7,425 2,619 1,856 10,044 11,900 (4,754) 2000 12/28/2004 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 16501 Commerce Drive (O) Dahlgren, VA — 522 2,090 1,040 522 3,130 3,652 (1,544) 2002 12/21/2004 16539 Commerce Drive (O) Dahlgren, VA — 688 2,860 2,326 688 5,186 5,874 (3,058) 1990 12/21/2004 16541 Commerce Drive (O) Dahlgren, VA — 773 3,094 2,596 773 5,690 6,463 (2,989) 1996 12/21/2004 16543 Commerce Drive (O) Dahlgren, VA — 436 1,742 838 436 2,580 3,016 (1,348) 2002 12/21/2004 1751 Pinnacle Drive (O) McLean, VA — 10,486 42,339 33,825 10,486 76,164 86,650 (42,720) 1989/1995 9/23/2004 1753 Pinnacle Drive (O) McLean, VA — 8,275 34,353 24,092 8,275 58,445 66,720 (28,325) 1976/2004 9/23/2004 206 Research Boulevard (O) Aberdeen, MD — — — — — — — — 2012 9/14/2007 209 Research Boulevard (O) Aberdeen, MD — 134 1,711 543 134 2,254 2,388 (687) 2010 9/14/2007 210 Research Boulevard (O) Aberdeen, MD — 113 1,402 426 113 1,828 1,941 (543) 2010 9/14/2007 2100 L Street (O) Washington, DC — 57,385 94,152 — 57,385 94,152 151,537 (1,987) 2020 8/11/2015 2100 Rideout Road (O) Huntsville, AL — — 7,336 2,995 — 10,331 10,331 (2,274) 2016 3/23/2010 22289 Exploration Drive (O) Lexington Park, MD — 1,422 5,719 2,129 1,422 7,848 9,270 (4,369) 2000 3/24/2004 22299 Exploration Drive (O) Lexington Park, MD — 1,362 5,791 3,049 1,362 8,840 10,202 (5,297) 1998 3/24/2004 22300 Exploration Drive (O) Lexington Park, MD — 1,094 5,038 2,770 1,094 7,808 8,902 (4,134) 1997 11/9/2004 22309 Exploration Drive (O) Lexington Park, MD — 2,243 10,419 8,114 2,243 18,533 20,776 (8,947) 1984/1997 3/24/2004 23535 Cottonwood Parkway (O) California, MD — 692 3,051 648 692 3,699 4,391 (2,193) 1984 3/24/2004 250 W Pratt St (O) Baltimore, MD — 8,057 34,588 18,482 8,057 53,070 61,127 (18,418) 1985 3/19/2015 2600 Park Tower Drive (O) Vienna, VA — 20,284 34,443 4,621 20,284 39,064 59,348 (8,392) 1999 4/15/2015 2691 Technology Drive (O) Annapolis Junction, MD — 2,098 17,334 5,565 2,098 22,899 24,997 (12,224) 2005 5/26/2000 2701 Technology Drive (O) Annapolis Junction, MD — 1,737 15,266 7,033 1,737 22,299 24,036 (13,380) 2001 5/26/2000 2711 Technology Drive (O) Annapolis Junction, MD — 2,251 21,611 4,335 2,251 25,946 28,197 (14,988) 2002 11/13/2000 2720 Technology Drive (O) Annapolis Junction, MD — 3,863 29,272 2,897 3,863 32,169 36,032 (14,204) 2004 1/31/2002 2721 Technology Drive (O) Annapolis Junction, MD — 4,611 14,597 3,783 4,611 18,380 22,991 (10,792) 2000 10/21/1999 2730 Hercules Road (O) Annapolis Junction, MD — 8,737 31,612 8,998 8,737 40,610 49,347 (23,935) 1990 9/28/1998 30 Light Street (O) Baltimore, MD — — 12,101 1,008 — 13,109 13,109 (2,308) 2009 8/7/2015 300 Secured Gateway (O) Annapolis Junction, MD — — 3,128 — — 3,128 3,128 — (7) 3/23/2010 300 Sentinel Drive (O) Annapolis Junction, MD — 1,517 59,165 2,569 1,517 61,734 63,251 (18,370) 2009 11/14/2003 302 Sentinel Drive (O) Annapolis Junction, MD — 2,648 29,687 2,293 2,648 31,980 34,628 (10,987) 2007 11/14/2003 304 Sentinel Drive (O) Annapolis Junction, MD — 3,411 24,917 4,875 3,411 29,792 33,203 (12,067) 2005 11/14/2003 306 Sentinel Drive (O) Annapolis Junction, MD — 3,260 22,592 3,303 3,260 25,895 29,155 (10,098) 2006 11/14/2003 308 Sentinel Drive (O) Annapolis Junction, MD — 1,422 26,208 2,354 1,422 28,562 29,984 (7,882) 2010 11/14/2003 310 Sentinel Way (O) Annapolis Junction, MD — 2,372 42,591 — 2,372 42,591 44,963 (6,103) 2016 11/14/2003 310 The Bridge Street (O) Huntsville, AL — 261 26,530 5,227 261 31,757 32,018 (12,236) 2009 8/9/2011 312 Sentinel Way (O) Annapolis Junction, MD — 3,138 27,797 — 3,138 27,797 30,935 (5,084) 2014 11/14/2003 314 Sentinel Way (O) Annapolis Junction, MD — 1,254 7,741 — 1,254 7,741 8,995 (1,480) 2008 11/14/2003 316 Sentinel Way (O) Annapolis Junction, MD — 2,748 38,156 193 2,748 38,349 41,097 (9,410) 2011 11/14/2003 318 Sentinel Way (O) Annapolis Junction, MD — 2,185 28,426 560 2,185 28,986 31,171 (11,482) 2005 11/14/2003 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 320 Sentinel Way (O) Annapolis Junction, MD — 2,067 21,623 127 2,067 21,750 23,817 (7,606) 2007 11/14/2003 322 Sentinel Way (O) Annapolis Junction, MD — 2,605 22,827 1,910 2,605 24,737 27,342 (9,329) 2006 11/14/2003 324 Sentinel Way (O) Annapolis Junction, MD — 1,656 23,018 6 1,656 23,024 24,680 (6,531) 2010 6/29/2006 4000 Market Street (O) Huntsville, AL 6,052 — 9,187 — — 9,187 9,187 (626) 2018 3/23/2010 410 National Business Parkway (O) Annapolis Junction, MD — 1,831 23,257 2,259 1,831 25,516 27,347 (6,032) 2012 6/29/2006 4100 Market Street (O) Huntsville, AL 5,269 — 8,020 7 — 8,027 8,027 (506) 2019 3/23/2010 420 National Business Parkway (O) Annapolis Junction, MD — 2,370 29,534 148 2,370 29,682 32,052 (5,467) 2013 6/29/2006 430 National Business Parkway (O) Annapolis Junction, MD — 1,852 21,563 1,893 1,852 23,456 25,308 (5,746) 2011 6/29/2006 44408 Pecan Court (O) California, MD — 817 1,583 1,751 817 3,334 4,151 (1,983) 1986 3/24/2004 44414 Pecan Court (O) California, MD — 405 1,619 1,138 405 2,757 3,162 (1,686) 1986 3/24/2004 44417 Pecan Court (O) California, MD — 434 3,822 180 434 4,002 4,436 (2,195) 1989/2015 3/24/2004 44420 Pecan Court (O) California, MD — 344 890 291 344 1,181 1,525 (607) 1989 11/9/2004 44425 Pecan Court (O) California, MD — 1,309 3,506 2,394 1,309 5,900 7,209 (3,757) 1997 5/5/2004 45310 Abell House Lane (O) California, MD — 2,272 13,808 878 2,272 14,686 16,958 (3,888) 2011 8/30/2010 4600 River Road (O) College Park, MD — — 24,032 — — 24,032 24,032 (436) 2020 1/29/2008 46579 Expedition Drive (O) Lexington Park, MD — 1,406 5,796 2,874 1,406 8,670 10,076 (4,563) 2002 3/24/2004 46591 Expedition Drive (O) Lexington Park, MD — 1,200 7,199 3,408 1,200 10,607 11,807 (4,557) 2005 3/24/2004 4851 Stonecroft Boulevard (O) Chantilly, VA — 1,878 11,558 194 1,878 11,752 13,630 (5,001) 2004 8/14/2002 540 National Business Parkway (O) Annapolis Junction, MD — 2,035 31,249 41 2,035 31,290 33,325 (3,321) 2017 6/29/2006 5520 Research Park Drive (O) Catonsville, MD — — 20,072 1,757 — 21,829 21,829 (7,078) 2009 4/4/2006 5522 Research Park Drive (O) Catonsville, MD — — 4,550 855 — 5,405 5,405 (1,851) 2007 3/8/2006 560 National Business Parkway (O) Annapolis Junction, MD — 2,193 28,973 — 2,193 28,973 31,166 — (7) 6/29/2006 5801 University Research Court (O) College Park, MD 11,120 — 17,431 144 — 17,575 17,575 (1,772) 2018 1/29/2008 5825 University Research Court (O) College Park, MD 19,552 — 22,771 1,678 — 24,449 24,449 (8,014) 2008 1/29/2008 5850 University Research Court (O) College Park, MD 20,686 — 31,906 894 — 32,800 32,800 (9,746) 2008 1/29/2008 6000 Redstone Gateway (O) Huntsville, AL — — 8,550 — — 8,550 8,550 (201) 2020 3/23/2010 610 Guardian Way (O) Annapolis Junction, MD — 7,636 49,873 — 7,636 49,873 57,509 (276) 2021 6/29/2006 6200 Redstone Gateway (O) Huntsville, AL — — 14,067 — — 14,067 14,067 — (7) 3/23/2010 6700 Alexander Bell Drive (O) Columbia, MD — 1,755 7,019 9,541 1,755 16,560 18,315 (9,466) 1988 5/14/2001 6708 Alexander Bell Drive (O) Columbia, MD — 897 12,693 1,618 897 14,311 15,208 (4,956) 1988/2016 5/14/2001 6711 Columbia Gateway Drive (O) Columbia, MD — 2,683 23,239 2,258 2,683 25,497 28,180 (9,995) 2006-2007 9/28/2000 6716 Alexander Bell Drive (O) Columbia, MD — 1,242 4,969 4,672 1,242 9,641 10,883 (6,399) 1990 12/31/1998 6721 Columbia Gateway Drive (O) Columbia, MD — 1,753 34,090 7,318 1,753 41,408 43,161 (11,406) 2009 9/28/2000 6724 Alexander Bell Drive (O) Columbia, MD — 449 5,039 2,492 449 7,531 7,980 (4,042) 2001 5/14/2001 6731 Columbia Gateway Drive (O) Columbia, MD — 2,807 19,098 5,689 2,807 24,787 27,594 (14,085) 2002 3/29/2000 6740 Alexander Bell Drive (O) Columbia, MD — 1,424 4,209 757 1,424 4,966 6,390 (2,627) 1992 12/31/1998 6741 Columbia Gateway Drive (O) Columbia, MD — 675 1,711 176 675 1,887 2,562 (715) 2008 9/28/2000 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 6750 Alexander Bell Drive (O) Columbia, MD — 1,263 12,461 5,856 1,263 18,317 19,580 (11,133) 2001 12/31/1998 6760 Alexander Bell Drive (O) Columbia, MD — 890 3,561 3,915 890 7,476 8,366 (5,115) 1991 12/31/1998 6940 Columbia Gateway Drive (O) Columbia, MD — 3,545 9,916 9,227 3,545 19,143 22,688 (11,631) 1999 11/13/1998 6950 Columbia Gateway Drive (O) Columbia, MD — 3,596 28,312 3,223 3,596 31,535 35,131 (12,711) 1998/2019 10/22/1998 7000 Columbia Gateway Drive (O) Columbia, MD — 3,131 12,103 8,551 3,131 20,654 23,785 (10,921) 1999 5/31/2002 7000 Redstone Gateway (O) Huntsville, AL — — 897 — — 897 897 — (7) 3/23/2010 7005 Columbia Gateway Drive (L) Columbia, MD — 3,036 747 — 3,036 747 3,783 — (6) 6/26/2014 7015 Albert Einstein Drive (O) Columbia, MD — 2,058 6,093 3,560 2,058 9,653 11,711 (5,005) 1999 12/1/2005 7061 Columbia Gateway Drive (O) Columbia, MD — 729 3,094 2,884 729 5,978 6,707 (3,608) 2000 8/30/2001 7063 Columbia Gateway Drive (O) Columbia, MD — 902 3,684 3,470 902 7,154 8,056 (4,721) 2000 8/30/2001 7065 Columbia Gateway Drive (O) Columbia, MD — 919 3,763 3,145 919 6,908 7,827 (4,703) 2000 8/30/2001 7067 Columbia Gateway Drive (O) Columbia, MD — 1,829 11,823 6,683 1,829 18,506 20,335 (9,409) 2001 8/30/2001 7100 Redstone Gateway (O) Huntsville, AL — — 12,975 — — 12,975 12,975 (204) 2021 3/23/2010 7125 Columbia Gateway Drive (O) Columbia, MD — 20,487 49,844 24,637 20,487 74,481 94,968 (30,038) 1973/1999 6/29/2006 7130 Columbia Gateway Drive (O) Columbia, MD — 1,350 4,359 3,029 1,350 7,388 8,738 (4,101) 1989 9/19/2005 7134 Columbia Gateway Drive (O) Columbia, MD — 704 4,700 729 704 5,429 6,133 (1,988) 1990/2016 9/19/2005 7138 Columbia Gateway Drive (O) Columbia, MD — 1,104 3,518 2,963 1,104 6,481 7,585 (4,286) 1990 9/19/2005 7142 Columbia Gateway Drive (O) Columbia, MD — 1,342 7,148 2,771 1,342 9,919 11,261 (4,494) 1994/2018 9/19/2005 7150 Columbia Gateway Drive (O) Columbia, MD — 1,032 3,429 1,705 1,032 5,134 6,166 (1,938) 1991 9/19/2005 7150 Riverwood Drive (O) Columbia, MD — 1,821 4,388 1,953 1,821 6,341 8,162 (3,162) 2000 1/10/2007 7160 Riverwood Drive (O) Columbia, MD — 2,732 7,006 4,609 2,732 11,615 14,347 (5,300) 2000 1/10/2007 7170 Riverwood Drive (O) Columbia, MD — 1,283 3,096 2,387 1,283 5,483 6,766 (2,787) 2000 1/10/2007 7175 Riverwood Drive (O) Columbia, MD — 1,788 7,269 — 1,788 7,269 9,057 (1,479) 1996/2013 7/27/2005 7200 Redstone Gateway (O) Huntsville, AL — — 8,348 81 — 8,429 8,429 (1,611) 2013 3/23/2010 7200 Riverwood Drive (O) Columbia, MD — 4,089 22,630 4,693 4,089 27,323 31,412 (13,365) 1986 10/13/1998 7205 Riverwood Drive (O) Columbia, MD — 1,367 21,419 — 1,367 21,419 22,786 (4,523) 2013 7/27/2005 7272 Park Circle Drive (O) Hanover, MD — 1,479 6,300 4,609 1,479 10,909 12,388 (5,971) 1991/1996 1/10/2007 7318 Parkway Drive (O) Hanover, MD — 972 3,888 1,647 972 5,535 6,507 (3,120) 1984 4/16/1999 7400 Redstone Gateway (O) Huntsville, AL — — 9,223 75 — 9,298 9,298 (1,519) 2015 3/23/2010 7467 Ridge Road (O) Hanover, MD — 1,565 3,116 5,997 1,565 9,113 10,678 (4,585) 1990 4/28/1999 7500 Advanced Gateway (O) Huntsville, AL — — 18,663 — — 18,663 18,663 (734) 2020 3/23/2010 7600 Advanced Gateway (O) Huntsville, AL — — 13,752 — — 13,752 13,752 (482) 2020 3/23/2010 7740 Milestone Parkway (O) Hanover, MD 16,432 3,825 34,176 1,254 3,825 35,430 39,255 (10,226) 2009 7/2/2007 7770 Backlick Road (O) Springfield, VA — 6,387 78,891 1,528 6,387 80,419 86,806 (17,275) 2012 3/10/2010 7880 Milestone Parkway (O) Hanover, MD — 4,857 26,836 1,338 4,857 28,174 33,031 (4,132) 2015 9/17/2013 8000 Rideout Road (O) Huntsville, AL — — 21,667 — — 21,667 21,667 (53) 2021 (7) 3/23/2010 8200 Rideout Road (O) (8) Huntsville, AL — — 16,890 — — 16,890 16,890 — (7) 3/23/2010 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) 8300 Rideout Road (O) (8) Huntsville, AL — — 18,301 — — 18,301 18,301 — (7) 3/23/2010 8600 Advanced Gateway (O) Huntsville, AL — — 27,298 — — 27,298 27,298 (711) 2020 3/23/2010 8621 Robert Fulton Drive (O) Columbia, MD — 2,317 12,642 6,191 2,317 18,833 21,150 (8,822) 2005-2006 6/10/2005 8661 Robert Fulton Drive (O) Columbia, MD — 1,510 3,764 3,302 1,510 7,066 8,576 (3,825) 2002 12/30/2003 8671 Robert Fulton Drive (O) Columbia, MD — 1,718 4,280 4,294 1,718 8,574 10,292 (5,066) 2002 12/30/2003 870 Elkridge Landing Road (O) Linthicum, MD — 2,003 9,442 10,464 2,003 19,906 21,909 (12,706) 1981 8/3/2001 8800 Redstone Gateway (O) Huntsville, AL 11,679 — 18,465 — — 18,465 18,465 (974) 2019 3/23/2010 891 Elkridge Landing Road (O) Linthicum, MD — 1,165 4,772 3,844 1,165 8,616 9,781 (5,472) 1984 7/2/2001 901 Elkridge Landing Road (O) Linthicum, MD — 1,156 4,437 6,034 1,156 10,471 11,627 (5,115) 1984 7/2/2001 911 Elkridge Landing Road (O) Linthicum, MD — 1,215 4,861 3,307 1,215 8,168 9,383 (5,116) 1985 4/30/1998 938 Elkridge Landing Road (O) Linthicum, MD — 922 4,748 1,534 922 6,282 7,204 (3,420) 1984 7/2/2001 939 Elkridge Landing Road (O) Linthicum, MD — 939 3,756 4,470 939 8,226 9,165 (6,064) 1983 4/30/1998 9651 Hornbaker Road (D) (9) Manassas, VA — 6,050 250,407 17,785 6,050 268,192 274,242 (82,385) 2010 9/14/2010 Arundel Preserve (L) Hanover, MD — 13,352 9,717 — 13,352 9,717 23,069 — (6) 7/2/2007 Canton Crossing Land (L) Baltimore, MD — 17,285 8,409 227 17,285 8,636 25,921 — (6) 10/27/2009 Canton Crossing Util Distr Ctr (O) Baltimore, MD — 6,100 10,450 1,689 6,100 12,139 18,239 (6,887) 2006 10/27/2009 Columbia Gateway - Southridge (L) Columbia, MD — 6,387 3,722 — 6,387 3,722 10,109 — (6) 9/20/2004 Dahlgren Technology Center (L) Dahlgren, VA — 978 178 — 978 178 1,156 — (6) 3/16/2005 Expedition VII (O) Lexington Park, MD — 705 7,208 — 705 7,208 7,913 — (7) 3/24/2004 IN 1 (O) Northern Virginia — 1,815 16,017 — 1,815 16,017 17,832 (1,136) 2019 8/31/2016 IN 2 (O) Northern Virginia — 2,627 28,936 — 2,627 28,936 31,563 (1,804) 2019 8/31/2016 M Square Research Park (L) College Park, MD — — 2,417 — — 2,417 2,417 — (6) 1/29/2008 MR Land (L) Northern Virginia — 9,038 554 — 9,038 554 9,592 — (6) 11/8/2018 National Business Park North (L) Annapolis Junction, MD — 18,232 36,875 — 18,232 36,875 55,107 — (6) 6/29/2006 North Gate Business Park (L) Aberdeen, MD — 1,755 5 — 1,755 5 1,760 — (6) 9/14/2007 NoVA Office A (O) (8) Chantilly, VA — 2,096 46,849 — 2,096 46,849 48,945 (8,096) 2015 7/18/2002 NoVA Office B (O) (8) Chantilly, VA — 739 38,376 — 739 38,376 39,115 (4,715) 2016 7/18/2002 NoVA Office C (O) (8) Chantilly, VA — 7,751 78,907 — 7,751 78,907 86,658 (477) 2021 7/18/2002 NoVA Office D (O) (8) Chantilly, VA — 6,587 40,559 — 6,587 40,559 47,146 (4,466) 2017 7/2/2013 Oak Grove A (O) Northern Virginia — 12,866 34,814 — 12,866 34,814 47,680 (1,358) 2020 11/1/2018 Oak Grove B (O) Northern Virginia — 12,866 41,083 — 12,866 41,083 53,949 (1,832) 2019 11/1/2018 Oak Grove C (O) Northern Virginia — 9,491 64,671 — 9,491 64,671 74,162 — (7) 11/1/2018 Oak Grove Phase II (L) Northern Virginia — 13,992 13,820 — 13,992 13,820 27,812 — (6) 11/1/2018 Old Annapolis Road (O) Columbia, MD — 1,637 5,500 6,755 1,637 12,255 13,892 (5,362) 1974/1985 12/14/2000 P2 A (O) Northern Virginia — 16,853 40,132 — 16,853 40,132 56,985 (1,739) 2020 5/2/2019 P2 B (O) Northern Virginia — 22,839 36,362 — 22,839 36,362 59,201 (1,194) 2020 5/2/2019 P2 C (O) Northern Virginia — 14,869 31,482 — 14,869 31,482 46,351 (828) 2020 5/2/2019 Initial Cost Gross Amounts Carried Property (Type) (1) Location Encumbrances (2) Land Building Costs Capitalized Subsequent to Acquisition Land Building Total Accumulated Depreciation (4) Year Built or Renovated Date Acquired (5) Patriot Ridge (L) Springfield, VA — 18,517 14,573 — 18,517 14,573 33,090 — (6) 3/10/2010 Project EL (O) Confidential-USA — 7,430 45,226 — 7,430 45,226 52,656 (552) 2021 1/20/2006 Project EX (O) (10) Confidential-USA — 13,010 19,097 — 13,010 19,097 32,107 (1,174) 2018 7/16/2008 PS A (O) Northern Virginia — 4,078 2,200 — 4,078 2,200 6,278 — (7) 1/27/2005 PS B (O) Northern Virginia — 3,468 1,940 — 3,468 1,940 5,408 — (7) 1/27/2005 Redstone Gateway (L) Huntsville, AL — — 29,937 — — 29,937 29,937 — (6) 3/23/2010 Sentry Gateway - T (O) San Antonio, TX — 14,020 38,804 13 14,020 38,817 52,837 (14,443) 1982/2008 3/30/2005 Sentry Gateway - V (O) San Antonio, TX — — 1,066 — — 1,066 1,066 (348) 2007 3/30/2005 Sentry Gateway - W (O) San Antonio, TX — — 1,884 71 — 1,955 1,955 (599) 2009 3/30/2005 Sentry Gateway - X (O) San Antonio, TX — 1,964 21,178 — 1,964 21,178 23,142 (5,905) 2010 1/20/2006 Sentry Gateway - Y (O) San Antonio, TX — 1,964 21,298 — 1,964 21,298 23,262 (5,940) 2010 1/20/2006 Sentry Gateway - Z (O) San Antonio, TX — 1,964 30,573 — 1,964 30,573 32,537 (5,203) 2015 6/14/2005 SP Manassas (L) Manassas, VA — 8,156 300 — 8,156 300 8,456 — (6) 7/24/2019 Westfields - Park Center (L) Chantilly, VA — 8,667 3,155 — 8,667 3,155 11,822 — (6) 7/2/2013 Other Developments, including Various — — 506 259 — 765 765 (115) Various Various $ 121,425 $ 720,485 $ 3,635,390 $ 603,834 $ 720,485 $ 4,239,224 $ 4,959,709 $ (1,234,908) (1) A legend for the Property Type follows: (O) = Office or Data Center Shell Property; (L) = Land held or pre-development; (D) = Wholesale Data Center; and (V) = Various. (2) Excludes our Revolving Credit Facility of $76.0 million, term loan facilities of $299.4 million, unsecured senior notes of $1.8 billion, unsecured notes payable of $753,000, and deferred financing costs, net of premiums, on the remaining loans of $798,000. (3) The aggregate cost of these assets for Federal income tax purposes was approximately $3.7 billion as of December 31, 2021. (4) The estimated lives over which depreciation is recognized follow: Building and land improvements: 10-40 years; and tenant improvements: related lease terms. (5) The acquisition date of multi-parcel properties reflects the date of the earliest parcel acquisition. The acquisition date of properties owned through real estate joint ventures reflects the date of the formation of the joint venture. (6) Held as of December 31, 2021. (7) Under development as of December 31, 2021. (8) The carrying amounts of these properties exclude allocated costs of the garage being constructed to support the properties. (9) Classified as held for sale as of December 31, 2021. (10) This property represents land under a long-term contract. The following table summarizes our changes in cost of properties for the years ended December 31, 2021, 2020 and 2019 (in thousands): 2021 2020 2019 Beginning balance $ 4,686,802 $ 4,348,006 $ 4,148,529 Improvements and other additions 342,684 405,940 480,418 Sales (1) (103,097) (65,475) (242,497) Impairments — (1,530) (329) Other dispositions (4,511) (139) (340) Reclassification from (to) right-of-use asset 37,831 — (37,775) Ending balance $ 4,959,709 $ 4,686,802 $ 4,348,006 The following table summarizes our changes in accumulated depreciation for the same time periods (in thousands): 2021 2020 2019 Beginning balance $ 1,124,253 $ 1,007,120 $ 897,903 Depreciation expense 130,604 119,377 117,973 Sales (1) (15,438) (2,105) (8,416) Other dispositions (4,511) (139) (340) Ending balance $ 1,234,908 $ 1,124,253 $ 1,007,120 (1) Includes our sale, through a series of transactions, of ownership interests in data center shells through newly-formed unconsolidated real estate joint ventures, as described in Note 4 to our consolidated financial statements.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation These consolidated financial statements include the accounts of COPT, the Operating Partnership, their subsidiaries and other entities in which COPT has a majority voting interest and control. We also consolidate certain entities when control of such entities can be achieved through means other than voting rights (“variable interest entities” or “VIEs”) if we are deemed to be the primary beneficiary of such entities. We eliminate all intercompany balances and transactions in consolidation. We use the equity method of accounting when we own an interest in an entity and can exert significant influence over but cannot control the entity’s operations. We discontinue equity method accounting if our investment in an entity (and net advances) is reduced to zero unless we have guaranteed obligations of the entity or are otherwise committed to provide further financial support for the entity.
Reclassifications	Reclassifications We reclassified certain amounts from prior periods to conform to the current period presentation of our consolidated financial statements with no effect on previously reported net income or equity, including amounts reclassified in conjunction with the transfer of our wholesale data center to discontinued operations in 2021. We provide disclosure regarding our discontinued operations in Note 4.
Use of Estimates in the Preparation of Financial Statements	Use of Estimates in the Preparation of Financial Statements We make estimates and assumptions when preparing financial statements under generally accepted accounting principles (“GAAP”). These estimates and assumptions affect various matters, including: • the reported amounts of assets and liabilities in our consolidated balance sheets as of the dates of the financial statements; • the disclosure of contingent assets and liabilities as of the dates of the financial statements; and • the reported amounts of revenues and expenses in our consolidated statements of operations during the reporting periods.
Properties	Properties We report properties to be developed or held and used in operations at our depreciated cost, reduced for impairment losses. We capitalize direct and indirect project costs (including related compensation and other indirect costs), interest expense and real estate taxes associated with properties, or portions thereof, undergoing development or redevelopment activities. In capitalizing interest expense, if there is a specific borrowing for a property undergoing development or redevelopment activities, we apply the interest rate of that borrowing to the average accumulated expenditures that do not exceed such borrowing; for the portion of expenditures exceeding any such specific borrowing, we apply our weighted average interest rate on other borrowings to the expenditures. We continue to capitalize costs while development or redevelopment activities are underway until a property becomes “operational,” which occurs when lease terms commence (generally when the tenant has control of the leased space and we have delivered the premises to the tenant as required under the terms of such lease), but no later than one year after the cessation of major construction activities. When leases commence on portions of a newly-developed or redeveloped property in the period prior to one year from the cessation of major construction activities, we consider that property to be “partially operational.” When a property is partially operational, we allocate the costs associated with the property between the portion that is operational and the portion under development. We start depreciating costs associated with newly-developed or redeveloped properties as they become operational. For newly-developed properties, we classify improvements provided under the terms of a lease that are deemed to be landlord assets (as discussed further below) as new building development costs. Most of our leases provide for some form of improvements to leased space. When we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets. If the improvements are landlord assets, we capitalize the cost of the improvements and recognize depreciation expense over the estimated useful lives of the assets as discussed below. We recognize any payments from the tenant for such assets as lease revenue over the term of the lease. If the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset and amortize it as a reduction of rental revenue over the term of the lease. In determining whether improvements constitute landlord or tenant assets, we consider numerous factors, including whether the economic substance of the lease terms is properly reflected and whether the improvements: have value to us as real estate; are unique to the tenant or reusable by other tenants; may be altered or removed by the tenant without our consent or without compensating us for any lost fair value; or are owned, and remain, with us or the tenant at the end of the lease term. We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years We report properties disposed or classified as held for sale as discontinued operations when the disposition represents a strategic shift having a major effect on our operations and financial results (such as a disposition of a reportable segment or subsegment or major line of business). For discontinued operations, we classify for all periods presented the associated: assets as held for sale on our consolidated balance sheets; and results of operations as discontinued operations on our consolidated statements of operations (including interest expense on debt specifically identifiable to such components). For periods in which a property not reported as discontinued operations is classified as held for sale, we classify the assets of the property’s asset group as held for sale on our consolidated balance sheets.
Sale of Properties	Sales of PropertiesWe recognize gains from sales of consolidated interests in properties to non-customer third parties when we have transferred control of such interests.
Impairment of Properties	Impairment of Properties We assess the asset groups associated with each of our properties, including operating properties, properties in development, land held for future development, related intangible assets, right-of-use assets, deferred rents receivable and lease liabilities, for indicators of impairment quarterly or when circumstances indicate that an asset group may be impaired. If our analyses indicate that the carrying values of certain properties’ asset groups may be impaired, we perform a recovery analysis for such asset groups. For properties to be held and used, we analyze recoverability based on the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over, in most cases, a ten-year holding period. If we believe it is more likely than not that we will dispose of the properties earlier, we analyze recoverability using a probability weighted analysis of the estimated undiscounted future cash flows expected to be generated from the operations and eventual disposition of the properties over the various possible holding periods. If the analysis indicates that the carrying value of a tested property’s asset group is not recoverable from its estimated future cash flows, the property’s asset group is written down to the property’s estimated fair value and an impairment loss is recognized. If and when our plans change, we revise our recoverability analyses to use the cash flows expected from the operations and eventual disposition of such property using holding periods that are consistent with our revised plans. Changes in holding periods may require us to recognize impairment losses. Fair values are estimated based on contract prices, indicative bids, discounted cash flow analyses, yield analyses or comparable sales analyses. Estimated cash flows used in our impairment analyses are based on our plans for the property and our views of market and economic conditions. The estimates consider items such as current and future market rental and occupancy rates, estimated operating and capital expenditures and recent sales data for comparable properties; most of these items are influenced by market data obtained from real estate leasing and brokerage firms and our direct experience with the properties and their markets.
Acquisition of Operating Properties	Acquisition of Operating Properties Upon completion of operating property acquisitions, we allocate the purchase price to tangible and intangible assets and liabilities associated with such acquisitions based on our estimates of their fair values. We determine these fair values by using market data and independent appraisals available to us and making numerous estimates and assumptions. We allocate operating property acquisitions to the following components: • properties based on a valuation performed under the assumption that the property is vacant upon acquisition (the “if-vacant value”). The if-vacant value is allocated between land and buildings or, in the case of properties under development, development in progress. We also allocate additional amounts to properties for in-place tenant improvements based on our estimate of improvements per square foot provided under market leases that would be attributable to the remaining non-cancelable terms of the respective leases; • above- and below-market lease intangible assets or liabilities based on the present value (using an interest rate reflective of the risks associated with the leases acquired) of the difference between: (1) the contractual amounts to be received pursuant to the in-place leases; and (2) our estimate of fair market lease rates for the corresponding space, measured over a period equal to the remaining non-cancelable term of the lease. The capitalized above- and below-market lease values are amortized as adjustments to lease revenue over the remaining lease terms of the respective leases, and to renewal periods in the case of below-market leases; • in-place lease value based on our estimates of: (1) the present value of additional income to be realized as a result of leases being in place on the acquired properties; and (2) costs to execute similar leases. Our estimate of costs to execute similar leases includes leasing commissions, legal and other related costs; • tenant relationship value based on our evaluation of the specific characteristics of each tenant’s lease and our overall relationship with that respective tenant. Characteristics we consider in determining these values include the nature and extent of our existing business relationships with the tenant, growth prospects for developing new business with the tenant, the tenant’s credit quality and expectations of lease renewals, among other factors; and • above- and below-market cost arrangements (such as real estate tax treaties or above- or below-market ground leases) based on the present value of the expected benefit from any such arrangements in place on the property at the time of acquisition.
Leased Assets, as a Lessee	Leased Assets, as a Lessee We recognize right-of-use assets and lease liabilities for land and other assets leased by us from third parties for terms of at least one year. We recognize lease expense over lease terms on a straight-line basis for operating leases and on an effective interest method basis for finance leases. In determining right-of-use assets and lease liabilities, we estimate an appropriate incremental borrowing rate on a fully-collateralized basis for the terms of the leases. Since the terms under our land leases are usually significantly longer than the terms of borrowings available to us on a fully-collateralized basis, our estimates of rates for such leases require significant judgment, and consider factors such as estimated interest rates available to us on a fully-collateralized basis for shorter-termed debt and U.S. Treasury rates.
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents include all cash and liquid investments that mature three months or less from when they are purchased. Cash equivalents are reported at cost, which approximates fair value. We maintain our cash in bank accounts in amounts that may exceed Federally insured limits at times. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions.
Investments in Marketable Securities	Investments in Marketable SecuritiesWe classify marketable securities as trading securities when we have the intent to sell such securities in the near term, and classify other marketable securities as available-for-sale securities. We determine the appropriate classification of investments in marketable securities at the acquisition date and re-evaluate the classification at each balance sheet date. We report investments in marketable securities classified as trading securities at fair value (which is included in the line entitled “Prepaid expenses and other assets, net” on our consolidated balance sheets), with unrealized gains and losses recognized through earnings; on our consolidated statements of cash flows, we classify cash flows from these securities as operating activities.
Receivables and Credit Losses	Receivables and Credit Losses We evaluate our receivables from customers and borrowers for collectability and recognize estimated credit losses on these receivables. We use judgment in estimating these losses based on the credit status of the entities associated with the individual receivables and payment history. Effective January 1, 2020, we adopted guidance issued by the Financial Accounting Standards Board (“FASB”) that changed how we measure credit losses for most financial assets and certain other instruments not measured at fair value through net income from an incurred loss model to an expected loss approach. We adopted this guidance using the modified retrospective transition method under which we recognized a $5.5 million allowance for credit losses by means of a cumulative-effect adjustment to cumulative distributions in excess of net income and did not adjust prior comparative reporting periods. Our consolidated statements of operations reflect adjustments for changes in our expected credit losses occurring subsequent to adoption of this guidance. Our items within the scope of this guidance included the following: • investing receivables, as disclosed in Note 8; • tenant notes receivable; • net investment in sales-type leases; • other assets comprised of non-lease revenue related accounts receivable (primarily from construction contract services) and contract assets from unbilled construction contract revenue; and • off-balance sheet credit exposures. Under this guidance, we recognize an estimate of our expected credit losses on these items as an allowance, as the guidance requires that financial assets be measured on an amortized cost basis and be presented at the net amount expected to be collected (or as a separate liability in the case of off-balance sheet credit exposures). The allowance represents the portion of the amortized cost basis that we do not expect to collect (or loss we expect to incur in the case of off-balance sheet credit exposures) due to credit over the contractual life based on available information relevant to assessing the collectability of cash flows, which includes consideration of past events, current conditions and reasonable and supportable forecasts of future economic conditions (including consideration of asset- or borrower-specific factors). The guidance requires the allowance for expected credit losses to reflect the risk of loss, even when that risk is remote. An allowance for credit losses is measured and recorded upon the initial recognition of a financial asset (or off-balance sheet credit exposure), regardless of whether it is originated or purchased. Quarterly, the expected losses are re-estimated, considering any cash receipts and changes in risks or assumptions, with resulting adjustments recognized as credit loss expense or recoveries on our consolidated statements of operations. We estimate expected credit losses for in-scope items using historical loss rate information developed for varying classifications of credit risk and contractual lives. Due to our limited quantity of items within the scope of this guidance and the unique risk characteristics of such items, we individually assign each in-scope item a credit risk classification. The credit risk classifications assigned by us are determined based on credit ratings assigned by ratings agencies (as available) or are internally-developed based on available financial information, historical payment experience, credit documentation, other publicly available information and current economic trends. In addition, for certain items in which the risk of credit loss is affected by the economic performance of a real estate development project, we develop probability weighted scenario analyses for varying levels of performance in estimating our credit loss allowance (applicable to our notes receivable from the City of Huntsville disclosed in Note 8 and a tax incremental financing obligation disclosed in Note 19). For lease revenue, if collectability is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. Prior to our adoption of the credit loss guidance discussed above, we evaluated the collectability of both interest and principal of loans whenever events or changes in circumstances indicated such amounts may not be recoverable. A loan was impaired when it was probable that we would be unable to collect all amounts due according to the existing contractual terms. When a loan was impaired, the amount of the loss accrual was calculated by comparing the carrying amount of the investment to the present value of expected future cash flows discounted at the loan’s effective interest rate and the value of any collateral under such loan. When we believe that collection of interest income on an investing or tenant note receivable is not probable, we place the receivable on nonaccrual status, meaning interest income is recognized when payments are received rather than on an accrual basis. We write off receivables when we believe the facts and circumstances indicate that continued pursuit of collection is no longer warranted. When cash is received in connection with receivables for which we have previously recognized credit losses, we recognize reductions in our credit losses.
Intangible Assets and Deferred Revenue on Property Acquisitions	Intangible Assets and Deferred Revenue on Property Acquisitions We amortize intangible assets and deferred revenue on property acquisitions as follows: Asset Type Amortization Period Above- and below-market leases Related lease terms In-place lease value Related lease terms Tenant relationship value Estimated period of time that tenant will lease space in property Above- and below-market cost arrangements Term of arrangements We recognize the amortization of acquired above- and below-market leases as adjustments to rental revenue. We recognize the amortization of above- and below-market cost arrangements as adjustments to property operating expenses. We recognize the amortization of other intangible assets on property acquisitions as amortization expense.
Deferred Leasing and Deferred Financing Costs	Deferred Leasing Costs We defer costs incurred to obtain new tenant leases or extend existing tenant leases. We amortize these costs evenly over the lease terms. We classify leasing costs paid as an investing activity on our statements of cash flows since such costs are necessary in order for us to generate long-term future cash flows from our properties. When tenant leases are terminated early, we expense any unamortized deferred leasing costs associated with those leases over the shortened term of the lease. Deferred Financing Costs We defer costs of financing arrangements and recognize these costs as interest expense over the related debt terms on a straight-line basis, which approximates the amortization that would occur under the effective interest method of amortization. We expense any unamortized loan costs when loans are retired early. We present deferred costs of financing arrangements as a direct deduction from the related debt liability, except for costs attributable to line-of-credit arrangements and interest rate derivatives, which we present in the balance sheet in the line entitled “prepaid expenses and other assets, net”.
Interest Rate Derivatives	Interest Rate Derivatives Our primary objectives in using interest rate derivatives are to add stability to interest expense and to manage exposure to interest rate movements. To accomplish this objective, we use interest rate swaps as part of our interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable-rate amounts from a counterparty in exchange for our making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. We use interest rate swaps to hedge the cash flows associated with interest rates on variable-rate debt borrowings. We also use forward-starting interest rate swaps to hedge the cash flows associated with interest rates on forecasted fixed-rate borrowings. We recognize all derivatives as assets or liabilities on our consolidated balance sheet at fair value. We defer all changes in the fair value of designated cash flow hedges to accumulated other comprehensive income (“AOCI”) or loss (“AOCL”), reclassifying such deferrals to interest expense as interest expense is recognized on the hedged forecasted transactions. When an interest rate swap designated as a cash flow hedge no longer qualifies for hedge accounting and the hedged transactions are probable not to occur, we recognize changes in fair value of the hedge previously deferred to AOCI or AOCL, along with any changes in fair value occurring thereafter, through earnings. We do not use interest rate derivatives for trading or speculative purposes. We manage counter-party risk by only entering into contracts with major financial institutions based upon their credit ratings and other risk factors.
Noncontrolling Interests	Noncontrolling InterestsOur consolidated noncontrolling interests are comprised of interests in COPLP not owned by COPT and interests in consolidated real estate joint ventures not owned by us (discussed further in Note 6). We evaluate whether noncontrolling interests are subject to redemption features outside of our control. We classify noncontrolling interests that are currently redeemable for cash at the option of the holders or are probable of becoming redeemable as redeemable noncontrolling interests in the mezzanine section of our consolidated balance sheets; we adjust these interests each period to the greater of their fair value or carrying amount (initial amount as adjusted for allocations of income and losses and contributions and distributions), with a corresponding offset to additional paid-in capital on our consolidated balance sheets. Our other noncontrolling interests are reported in the equity section of our consolidated balance sheets.
Revenue Recognition	Revenue Recognition Lease and Other Property Revenue We lease real estate properties, comprised primarily of office properties and data center shells, to third parties. These leases usually include options under which the tenant may renew its lease based on market rates at the time of renewal, which are then typically subject to further negotiation. These leases occasionally provide the tenant with an option to terminate its lease early usually for a defined termination fee. Most of our lease revenue is from fixed contractual payments defined under the lease that, in most cases, escalate annually over the term of the lease. Our lease revenue also includes variable lease payments predominantly for tenant reimbursements of property operating expenses and lease termination fees. Property operating expense reimbursement structures vary, with some tenants responsible for all of a property’s expenses, while others are responsible for their share of a property’s expense only to the extent such expenses exceed amounts defined in the lease (which are derived from the property’s historical expense levels). Lease termination fees in most cases result from a tenant’s exercise of an existing right under a lease. Upon lease commencement, we evaluate leases to determine if they meet criteria set forth in lease accounting guidance for classification as sales-type leases or direct financing leases; if a lease meets none of these criteria, we classify the lease as an operating lease. Upon commencement of sales-type leases, we derecognize the underlying asset, recognizing in its place a net investment in the lease equal to the sum of the lease receivable and the present value of any unguaranteed residual asset and recognize any selling profit or loss created as a result of the difference between those two amounts. Similarly, for direct financing leases, the lessor derecognizes the underlying asset and recognizes a net investment in the lease, but, unlike in a sales-type lease, defers profit and amortizes it as interest income over the lease term. Our leases of properties as lessor are predominantly classified as operating leases, for which the underlying asset remains on our balance sheet and is depreciated consistently with other owned assets, with income recognized as described further below. We recognize minimum rents on operating leases, net of abatements, on a straight-line basis over the term of tenant leases. A lease term commences when: (1) the tenant has control of the leased space (legal right to use the property); and (2) we have delivered the premises to the tenant as required under the terms of the lease. The term of a lease includes the noncancellable periods of the lease along with periods covered by: (1) a tenant option to extend the lease if the tenant is reasonably certain to exercise that option; (2) a tenant option to terminate the lease if the tenant is reasonably certain not to exercise that option; and (3) an option to extend (or not to terminate) the lease in which exercise of the option is controlled by us as the lessor. When assessing the expected lease end date, we use judgment in contemplating the significance of: any penalties a tenant may incur should it choose not to exercise any existing options to extend the lease or exercise any existing options to terminate the lease; and economic incentives for the tenant based on any existing contract, asset, entity or market-based factors in the lease. While a significant portion of our portfolio is leased to the USG, and the majority of those leases consist of a series of one-year renewal options, or provide for early termination rights, we have concluded that exercise of existing renewal options, or continuation of such leases without exercising early termination rights, is reasonably certain for most of these leases. We report the amount by which our minimum rental revenue recognized on a straight-line basis under leases exceeds the contractual rent billings associated with such leases as deferred rent receivable on our consolidated balance sheets. Amounts by which our minimum rental revenue recognized on a straight-line basis under leases are less than the contractual rent billings associated with such leases are reported in liabilities as deferred revenue associated with operating leases on our consolidated balance sheets. In connection with a tenant’s entry into, or modification of, a lease, if we make cash payments to, or on behalf of, the tenant for purposes other than funding the construction of landlord assets, we generally defer the amount of such payments as lease incentives. As discussed above, when we are required to provide improvements under the terms of a lease, we determine whether the improvements constitute landlord assets or tenant assets; if the improvements are tenant assets, we defer the cost of improvements funded by us as a lease incentive asset. We amortize lease incentives as a reduction of rental revenue over the term of the lease. If collectability under a lease is not probable, revenue recognized is limited to the lesser of revenue that would have been recognized if collectability was probable or lease payments collected. We recognize lease revenue associated with tenant expense recoveries in the same periods in which we incur the related expenses, including tenant reimbursements of property taxes, utilities and other property operating expenses. We recognize fees received for lease terminations as revenue and write off against such revenue any (1) deferred rents receivable, and (2) deferred revenue, lease incentives and intangible assets that are amortizable into rental revenue associated with the leases; the resulting net amount is the net revenue from the early termination of the leases. When a tenant’s lease for space in a property is terminated early but the tenant continues to lease such space under a new or modified lease in the property, the net revenue from the early termination of the lease is recognized evenly over the remaining life of the new or modified lease in place on that property. Effective January 1, 2019, we adopted guidance issued by the FASB setting forth principles for the recognition, measurement, presentation and disclosure of leases, which required lessors of real estate to account for leases using an approach substantially equivalent to guidance previously in place for operating leases, direct financing leases and sales-type leases. Upon adoption, we elected to apply a package of practical expedients that enabled us to carry forward upon adoption our historical assessments of: expired or existing leases regarding their lease classification and deferred recognition of non-incremental direct leasing costs; and whether any expired or existing contracts are, or contain, leases. We also elected a practical expedient that enabled us to avoid the need to assess whether expired or existing land easements not previously accounted for as leases are, or contain, a lease. In addition, we elected a practical expedient to avoid separating non-lease components that otherwise would need to be accounted for under revenue accounting guidance (such as tenant reimbursements of property operating expenses) from the associated lease component since (1) the non-lease components have the same timing and pattern of transfer as the associated lease component and (2) the lease component, if accounted for separately, would be classified as an operating lease; this enables us to account for the combination of the lease component and non-lease components as an operating lease since the lease component is the predominant component of the combined components. Construction Contract and Other Service Revenues We enter into construction contracts to complete various design and construction services primarily for our USG tenants. The revenues and expenses from these services consist primarily of subcontracted costs that are reimbursed to us by our customers along with a fee. These services are an ancillary component of our overall operations, with small operating margins relative to the revenue. We review each contract to determine the performance obligations and allocate the transaction price based on the standalone selling price, as discussed further below. We recognize revenue under these contracts as services are performed in an amount that reflects the consideration we expect to receive in exchange for those services. Our performance obligations are satisfied over time as work progresses. Revenue recognition is determined using the input method based on costs incurred as of a point in time relative to the total estimated costs at completion to measure progress toward satisfying our performance obligations. We believe incurred costs of work performed best depicts the transfer of control of the services being transferred to the customer. In determining whether the performance obligations of each construction contract should be accounted for separately versus together, we consider numerous factors that may require significant judgment, including: whether the components contracted are substantially the same with the same pattern of transfer; whether the customer could contract with another party to perform construction based on our design project; and whether the customer can elect not to move forward after the design phase of the contract. Most of our contracts have a single performance obligation as the promise to transfer the services is not separately identifiable from other obligations in the contracts and, therefore, are not distinct. Some contracts have multiple performance obligations, most commonly due to having distinct project phases for design and construction that our customer is managing separately. In these cases, we allocate the transaction price between these performance obligations based on the relative standalone selling prices, which we determine by evaluating: the relative costs of each performance obligation; the expected operating margins (which typically do not vary significantly between obligations); and amounts set forth in the contracts for each obligation. Contract modifications, such as change orders, are routine for our construction contracts and are generally determined to be additions to the existing performance obligations because they would have been part of the initial performance obligations if they were identified at the initial contract date. We have three main types of compensation arrangements for our construction contracts: guaranteed maximum price (“GMP”); firm fixed price (“FFP”); and cost-plus fee. • GMP contracts provide for revenue equal to costs incurred plus a fee equal to a percentage of such costs, up to a maximum contract amount. We generally enter into GMP contracts for projects that are significant in nature based on the size of the project and total fees, and for which the full scope of the project has not been determined as of the contract date. GMP contracts are lower risk to us than FFP contracts since the costs and revenue move proportionately to one another. • FFP contracts provide for revenue equal to a fixed fee. These contracts are typically lower in value and scope relative to GMP contracts, and are generally entered into when the scope of the project is well defined. Typically, we assume more risk with FFP contracts than GMP contracts since the revenue is fixed and we could realize losses or less than expected profits if we incur more costs than originally estimated. However, these types of contracts offer the opportunity for additional profits when we complete the work for less than originally estimated. • Cost-plus fee contracts provide for revenue equal to costs incurred plus a fee equal to a percentage of such costs but, unlike GMP contracts, do not have a maximum contract amount. Similar to GMP contracts, cost-plus fee contracts are low risk to us since the costs and revenue move proportionately to one another. Construction contract cost estimates are based primarily on contracts in place with subcontractors to complete most of the work, but may also include assumptions, such as performance of subcontractors and cost and availability of materials, to project the outcome of future events over the course of the project. We review and update these estimates regularly as a significant change could affect the profitability of our construction contracts. We recognize adjustments in estimated profit on contracts under the cumulative catch-up method as the modification does not create a new performance obligation. Under this method, the impact of an adjustment to profit recorded to date on a contract is recognized in the period the adjustment is identified. Revenue and profit in future periods are recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on a contract, we recognize the total loss in the quarter it is identified. Our timing of revenue recognition for construction contracts generally differs from the timing of invoicing to customers. We recognize construction contract revenue as we satisfy our performance obligations. Payment terms and conditions vary by contract type. Under most of our contracts, we bill customers monthly, as work progresses, in accordance with the contract terms, with payment due in 30 days, although customers occasionally pay in advance of services being provided. We have determined that our contracts generally do not include a significant financing component. The primary purpose of the timing of our invoicing is for convenience, not to receive financing from our customers or to provide customers with financing. Additionally, the timing of transfer of the services is often at the discretion of the customer. Under most of our contracts, we bill customers one month subsequent to revenue recognition, resulting in contract assets representing unbilled construction revenue.
Expense Classification	Expense Classification We classify as property operating expenses costs incurred for property taxes, ground rents, utilities, property management, insurance, repairs and exterior and interior maintenance, as well as associated labor and indirect costs attributable to these costs. We classify as general, administrative and leasing expenses costs incurred for corporate-level management, public company administration, asset management, leasing, investor relations, marketing and corporate-level insurance (including general business and director and officers) and leasing prospects, as well as associated labor and indirect costs attributable to these expenses.
Share-Based Compensation	Share-Based Compensation We issue four forms of share-based compensation: restricted COPT common shares (“restricted shares”), deferred share awards (also known as restricted share units), performance share units (also known as performance share awards) (“PSUs”) and profit interest units (“PIUs”) (time-based and performance-based). We account for share-based compensation in accordance with authoritative guidance provided by the FASB that establishes standards for the accounting for transactions in which an entity exchanges its equity instruments for goods or services, focusing primarily on accounting for transactions in which an entity obtains employee services in share-based payment transactions. The guidance requires us to measure the cost of employee services received in exchange for an award of equity instruments based generally on the fair value of the award on the grant date; such cost is then recognized over the period during which the employee is required to provide service in exchange for the award. No compensation cost is recognized for equity instruments for which employees do not render the requisite service. The guidance also requires that share-based compensation be computed based on awards that are ultimately expected to vest; as a result, future forfeitures of awards are estimated at the time of grant and revised, if necessary, in subsequent periods if actual forfeitures differ from those estimates. If an award is voluntarily cancelled by an employee, we recognize the previously unrecognized cost associated with the original award on the date of such cancellation. We capitalize costs associated with share-based compensation attributable to employees engaged in development and redevelopment activities. We compute the fair value of restricted shares, time-based PIUs (“TB-PIUs”) and deferred share awards based on the fair value of COPT common shares on the grant date. We compute the fair value of PSUs and performance-based PIUs (“PB-PIUs”) using a Monte Carlo model. Significant assumptions used for that model include the following: the baseline common share value is the market value on the grant date; the risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant; and expected volatility is based on historical volatility of COPT’s common shares.
Income Taxes	Income Taxes COPT elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code. To qualify as a REIT, COPT must meet a number of organizational and operational requirements, including a requirement that it distribute at least 90% of its adjusted taxable income to its shareholders. As a REIT, COPT generally will not be subject to Federal income tax on taxable income that it distributes to its shareholders. If COPT fails to qualify as a REIT in any tax year, it will be subject to Federal income tax on its taxable income at regular corporate rates and may not be able to qualify as a REIT for four subsequent tax years. For Federal income tax purposes, dividends to shareholders may be characterized as ordinary income, capital gains or return of capital. The characterization of dividends paid on COPT’s common shares during each of the last three years was as follows: For the Years Ended December 31, 2021 2020 2019 Ordinary income 33.3 % 45.1 % 54.4 % Long-term capital gain 57.3 % 54.9 % 45.6 % Return of capital 9.4 % — % — % The dividends allocated to each of the above years for Federal income tax purposes included dividends paid on COPT’s common shares during each of those years except for the dividends paid on January 15, 2021 and 2020 (with a record date of December 31, 2020 and 2019, respectively), which were allocated for Federal income tax purposes to 2020 and 2019, respectively. We distributed all of COPT’s REIT taxable income in 2021, 2020 and 2019 and, as a result, did not incur Federal income tax in those years. The net basis of our consolidated assets and liabilities for tax reporting purposes was approximately $18 million lower than the amount reported on our consolidated balance sheet as of December 31, 2021.
Recent Accounting Pronouncements	Recent Accounting PronouncementsIn March 2020, the FASB issued guidance containing practical expedients for reference rate reform related activities pertaining to debt, leases, derivatives and other contracts. The guidance is optional and may be elected over time as reference rate reform activities occur. In 2020, we elected to apply an expedient to treat any changes in loans resulting from reference rate reform as debt modifications (as opposed to extinguishments) and hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of the hedge accounting expedients preserves the presentation of derivatives consistent with past presentation. We will continue to evaluate the impact of this guidance and may apply other elections as applicable as additional changes in the market occur.
Fair Value Measurement	Accounting standards define fair value as the exit price, or the amount that would be received upon sale of an asset or paid to transfer a liability in an orderly transaction between market participants as of the measurement date. The standards also establish a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that the most observable inputs be used when available. Observable inputs are inputs market participants would use in valuing the asset or liability developed based on market data obtained from sources independent of us. Unobservable inputs are inputs that reflect our assumptions about the factors market participants would use in valuing the asset or liability developed based upon the best information available in the circumstances. The hierarchy of these inputs is broken down into three levels: Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities; Level 2 inputs include (1) quoted prices for similar assets or liabilities in active markets, (2) quoted prices for identical or similar assets or liabilities in inactive markets and (3) inputs (other than quoted prices) that are observable for the asset or liability, either directly or indirectly; and Level 3 inputs are unobservable inputs for the asset or liability. Categorization within the valuation hierarchy is based upon the lowest level of input that is most significant to the fair value measurement.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2021
Accounting Policies [Abstract]
Schedule of the estimated useful lives of fixed assets	We depreciate our fixed assets using the straight-line method over their estimated useful lives as follows: Estimated Useful Lives Buildings and building improvements 10-40 years Land improvements 10-20 years Tenant improvements on operating properties Shorter of remaining useful lives of assets or related lease term Equipment and personal property 3-10 years
Schedule of amortization of intangible assets and deferred revenue	We amortize intangible assets and deferred revenue on property acquisitions as follows: Asset Type Amortization Period Above- and below-market leases Related lease terms In-place lease value Related lease terms Tenant relationship value Estimated period of time that tenant will lease space in property Above- and below-market cost arrangements Term of arrangements
Schedule of characterization of dividends declared on common and preferred shares	The characterization of dividends paid on COPT’s common shares during each of the last three years was as follows: For the Years Ended December 31, 2021 2020 2019 Ordinary income 33.3 % 45.1 % 54.4 % Long-term capital gain 57.3 % 54.9 % 45.6 % Return of capital 9.4 % — % — %

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2021
Fair Value Disclosures [Abstract]
Schedule of fair value assets and liabilities measured on recurring basis	The table below sets forth our financial assets and liabilities accounted for at fair value on a recurring basis as of December 31, 2021 and 2020 and the hierarchy level of inputs used in measuring their respective fair values under applicable accounting standards (in thousands): Description Quoted Prices in Significant Other Significant Total December 31, 2021: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 2,485 $ — $ — $ 2,485 Other 71 — — 71 Other marketable securities (1) 33 — — 33 Interest rate derivatives (1) — 355 — 355 Total assets $ 2,589 $ 355 $ — $ 2,944 Liabilities: Deferred compensation plan liability (2) $ — $ 2,556 $ — $ 2,556 Interest rate derivatives — 3,644 — 3,644 Total liabilities $ — $ 6,200 $ — $ 6,200 December 31, 2020: Assets: Marketable securities in deferred compensation plan (1) Mutual funds $ 3,008 $ — $ — $ 3,008 Other 19 — — 19 Other marketable securities (1) 30 — — 30 Total assets $ 3,057 $ — $ — $ 3,057 Liabilities: Deferred compensation plan liability (2) $ — $ 3,027 $ — $ 3,027 Interest rate derivatives — 9,522 — 9,522 Total liabilities $ — $ 12,549 $ — $ 12,549 (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)	12 Months Ended
	Dec. 31, 2021
Real Estate [Abstract]
Schedule of operating properties, net	Operating properties, net consisted of the following (in thousands): December 31, 2021 2020 Land $ 572,900 $ 522,219 Buildings and improvements 3,670,133 3,444,804 Less: Accumulated depreciation (1,152,523) (1,052,007) Operating properties, net $ 3,090,510 $ 2,915,016
Disposal Groups, Including Discontinued Operations	The table below sets forth the components of our wholesale data center’s assets classified as held for sale on our consolidated balance sheets (in thousands): December 31, 2021 2020 Properties, net $ 191,857 $ 200,264 Deferred rent receivable 462 1,025 Intangible assets on property acquisitions, net 73 95 Deferred leasing costs, net 307 436 Assets held for sale, net $ 192,699 $ 201,820 The table below sets forth our wholesale data center’s results of operations included in discontinued operations on our consolidated statements of operations and its operating and investing cash flows included on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, 2021 2020 2019 (in thousands) Revenues from real estate operations $ 30,490 $ 27,011 $ 29,405 Property operating expenses (16,842) (13,044) (12,694) Depreciation and amortization associated with real estate operations (10,290) (11,690) (12,061) Discontinued operations 3,358 2,277 4,650 Cash flows from operating activities $ 10,930 $ 16,051 $ 18,626 Cash flows from investing activities $ (1,912) $ (11,485) $ (805)

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Operating Lease Revenue Recognized	The table below sets forth our composition of lease revenue recognized between fixed and variable lease revenue (in thousands): For the Years Ended December 31, Lease revenue (1) 2021 2020 2019 Fixed $ 436,768 $ 404,244 $ 392,341 Variable 116,900 104,870 100,824 $ 553,668 $ 509,114 $ 493,165 (1) Excludes lease revenue from discontinued operations of which $22.3 million, $21.3 million and $20.0 million was fixed and $8.2 million, $5.7 million and $9.3 million was variable for 2021, 2020 and 2019, respectively.
Sales-type leases fixed contractual payments due	Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2021 Year Ending December 31, Operating leases Sales-type leases 2022 $ 430,910 $ 960 2023 391,551 960 2024 344,256 960 2025 256,725 960 2026 193,051 960 Thereafter 939,463 3,556 Total contractual payments $ 2,555,956 8,356 Less: Amount representing interest (2,162) Net investment in sales-type leases $ 6,194
Operating leases fixed contractual payments due	Fixed contractual payments due under our property leases were as follows (in thousands): As of December 31, 2021 Year Ending December 31, Operating leases Sales-type leases 2022 $ 430,910 $ 960 2023 391,551 960 2024 344,256 960 2025 256,725 960 2026 193,051 960 Thereafter 939,463 3,556 Total contractual payments $ 2,555,956 8,356 Less: Amount representing interest (2,162) Net investment in sales-type leases $ 6,194
Right-of-Use Assets and Lease Liabilities	Our property right-of-use assets consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Right-of-use assets Operating leases - Property Property - operating right-of-use assets $ 38,361 $ 40,570 Finance leases - Property (1) Property - finance right-of-use assets 2,238 40,425 Total right-of-use assets $ 40,599 $ 80,995 (1) On October 22, 2021, we acquired land leased in Washington, D.C., for which we had a $37.8 million right-of-use asset as of December 31, 2021, for a nominal amount under a bargain purchase option. Property lease liabilities consisted of the following (in thousands): As of December 31, Leases Balance Sheet Location 2021 2020 Lease liabilities Operating leases - Property Property - operating lease liabilities $ 29,342 $ 30,746 Finance leases - Property Other liabilities — 28 Total lease liabilities $ 29,342 $ 30,774
Lease Costs	The table below presents our total property lease cost (in thousands): Statement of Operations Location For the Years Ended December 31, Lease cost 2021 2020 2019 Operating lease cost Property leases - fixed Property operating expenses $ 4,011 $ 2,413 $ 1,664 Property leases - variable Property operating expenses 45 127 4 Finance lease cost Amortization of property right-of-use assets Property operating expenses 31 34 30 $ 4,087 $ 2,574 $ 1,698 The table below presents the effect of property lease payments on our consolidated statements of cash flows (in thousands): For the Years Ended December 31, Supplemental cash flow information 2021 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 3,206 $ 1,694 $ 1,004 Financing cash flows for financing leases $ 14 $ 674 $ 14
Operating Lease, Liability, Maturity	Payments on property operating leases were due as follows (in thousands): Year Ending December 31, December 31, 2021 2022 $ 3,297 2023 3,352 2024 3,403 2025 1,749 2026 1,530 Thereafter 122,448 Total lease payments 135,779 Less: Amount representing interest (106,437) Lease liability $ 29,342

Real Estate Joint Ventures (Tab

Real Estate Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2021
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 pertaining to our investments in consolidated real estate joint ventures as of December 31, 2021 (dollars in thousands): Nominal Ownership % December 31, 2021 (1) Date Acquired Total Encumbered Assets Total Liabilities Entity Location LW Redstone Company, LLC (2) 3/23/2010 85% Huntsville, Alabama $ 478,739 $ 89,589 $ 93,730 Stevens Investors, LLC 8/11/2015 95% Washington, D.C. 165,806 — 1,406 M Square Associates, LLC 6/26/2007 50% College Park, Maryland 101,515 60,795 52,589 $ 746,060 $ 150,384 $ 147,725 (1) Excludes amounts eliminated in consolidation. (2) As discussed below, we fund all capital requirements. Our partner generally receives distributions of the first $1.2 million of annual operating cash flows and we receive the remainder.
Schedule of information related to investments in unconsolidated real estate joint ventures	The table below sets forth information pertaining to our investments in unconsolidated real estate joint ventures accounted for using the equity method of accounting (dollars in thousands): Date Acquired Nominal Ownership % Number of Properties Carrying Value of Investment (1) Entity December 31, 2021 December 31, 2020 BRE-COPT 2 (2) 10/30/2020 10% 8 $ 15,579 $ 15,988 BREIT-COPT 6/20/2019 10% 9 12,460 13,315 BRE-COPT 3 6/2/2021 10% 2 11,850 — 19 $ 39,889 $ 29,303 (1) Included in the line entitled “investment in unconsolidated real estate joint ventures” on our consolidated balance sheets. (2) Our investment in BRE-COPT 2 was lower than our share of the joint venture’s equity by $7.2 million as of December 31, 2021 and $7.4 million as of December 31, 2020 due to a difference between our cost basis and our share of the joint venture’s underlying equity in its net assets. We recognize adjustments to our share of the joint venture’s earnings and losses resulting from this basis difference in the underlying assets of the joint venture.

Intangible Assets on Property_2

Intangible Assets on Property Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2021
Intangible Assets on Property Acquisitions
Schedule of intangible assets on real estate acquisitions	Intangible assets on property acquisitions consisted of the following (in thousands): December 31, 2021 December 31, 2020 Gross Carrying Amount Accumulated Amortization Net Gross Carrying Amount Accumulated Amortization Net In-place lease value $ 125,591 $ 118,983 $ 6,608 $ 128,693 $ 120,010 $ 8,683 Tenant relationship value 58,082 50,701 7,381 58,082 48,163 9,919 Above-market leases 13,718 13,435 283 13,718 13,380 338 Other 1,333 1,038 295 1,333 1,024 309 $ 198,724 $ 184,157 $ 14,567 $ 201,826 $ 182,577 $ 19,249

Investing Receivables (Tables)

Investing Receivables (Tables)	12 Months Ended
	Dec. 31, 2021
Receivables [Abstract]
Schedule of Investing Receivables	Investing receivables consisted of the following (in thousands): December 31, 2021 2020 Notes receivable from the City of Huntsville $ 77,784 $ 65,564 Other investing loans receivable 6,041 6,041 Amortized cost basis 83,825 71,605 Allowance for credit losses (1,599) (2,851) Investing receivables, net $ 82,226 $ 68,754

Prepaid Expenses and Other As_2

Prepaid Expenses and Other Assets, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Prepaid Expense and Other Assets [Abstract]
Schedule of prepaid expenses and other assets	Prepaid expenses and other assets, net consisted of the following (in thousands): December 31, 2021 2020 Lease incentives, net $ 51,486 $ 35,642 Construction contract costs in excess of billings, net 22,384 10,343 Prepaid expenses 20,058 19,690 Furniture, fixtures and equipment, net 9,599 10,433 Net investment in sales-type leases 6,194 6,573 Non-real estate equity investments 5,544 5,509 Restricted cash 4,054 3,664 Marketable securities in deferred compensation plan 2,556 3,027 Deferred tax asset, net 1,841 1,989 Deferred financing costs, net (1) 1,314 2,439 Other assets 5,708 5,274 Prepaid expenses and other assets, net $ 130,738 $ 104,583 (1) Represents deferred costs, net of accumulated amortization, attributable to our Revolving Credit Facility and interest rate derivatives .
Schedule of tax effects of temporary differences and carry forwards in net deferred tax assets	Deferred tax asset, net reported above includes the following tax effects of temporary differences and carry forwards of our TRS (in thousands): December 31, 2021 2020 Operating loss carry forward $ 1,835 $ 2,087 Property 30 103 Valuation allowance (24) (201) Deferred tax asset, net $ 1,841 $ 1,989

Debt, Net (Tables)

Debt, Net (Tables)	12 Months Ended
	Dec. 31, 2021
Debt Disclosure [Abstract]
Schedule of debt	Our debt consisted of the following (dollars in thousands): Carrying Value (1) as of December 31, December 31, 2021 2021 2020 Stated Interest Rates Scheduled Maturity Mortgage and Other Secured Debt: Fixed rate mortgage debt (2) $ 86,960 $ 139,991 3.82% - 4.62% (3) 2023-2026 Variable rate secured debt 33,667 115,119 LIBOR + 1.45% to 1.55% (4) 2025-2026 Total mortgage and other secured debt 120,627 255,110 Revolving Credit Facility 76,000 143,000 LIBOR + 0.775% to 1.45% (5) March 2023 Term Loan Facility 299,420 398,447 LIBOR + 1.00% to 1.65% (6) December 2022 Unsecured Senior Notes 2.25%, $400,000 aggregate principal 395,491 394,464 2.25% (7) March 2026 2.00%, $400,000 aggregate principal 396,512 — 2.00% (8) January 2029 2.75%, $600,000 aggregate principal 589,060 — 2.75% (9) April 2031 2.90%, $400,000 aggregate principal 394,441 — 2.90% (10) December 2033 3.60%, $350,000 aggregate principal — 348,888 3.60% (11) N/A 5.25%, $250,000 aggregate principal — 248,194 5.25% (12) N/A 5.00%, $300,000 aggregate principal — 297,915 5.00% (13) N/A Unsecured note payable 753 900 0% (14) May 2026 Total debt, net $ 2,272,304 $ 2,086,918 (1) The carrying values of our debt other than the Revolving Credit Facility reflect net deferred financing costs of $5.8 million as of December 31, 2021 and $5.9 million as of December 31, 2020. (2) Certain of the fixed rate mortgages carry interest rates that, upon assumption, were above or below market rates and therefore were recorded at their fair value based on applicable effective interest rates. The carrying values of these loans reflect net unamortized premiums totaling $155,000 as of December 31, 2020. (3) The weighted average interest rate on our fixed rate mortgage debt was 4.07% as of December 31, 2021. (4) The weighted average interest rate on our variable rate secured debt was 1.62% as of December 31, 2021. (5) The weighted average interest rate on the Revolving Credit Facility was 1.20% as of December 31, 2021. (6) The interest rate on this loan was 1.10% as of December 31, 2021. (7) The carrying value of these notes reflects an unamortized discount totaling $3.6 million as of December 31, 2021 and $4.5 million as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 2.48%. (8) The carrying value of these notes reflects an unamortized discount totaling $2.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.09%. Refer to paragraph below for further disclosure. (9) The carrying value of these notes reflects an unamortized discount totaling $9.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 2.94%. Refer to paragraph below for further disclosure. (10) The carrying value of these notes reflects an unamortized discount totaling $4.5 million as of December 31, 2021. The effective interest rate under the notes, including amortization of the issuance costs, was 3.01%. Refer to paragraph below for further disclosure. (11) The carrying value of these notes reflects an unamortized discount totaling $781,000 as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 3.70%. Refer to paragraph below for further disclosure. (12) The carrying value of these notes reflects an unamortized discount totaling $1.6 million as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 5.49%. Refer to paragraph below for further disclosure. (13) The carrying value of these notes reflects an unamortized discount totaling $1.8 million as of December 31, 2020. The effective interest rate under the notes, including amortization of the issuance costs, was 5.15%. Refer to paragraph below for further disclosure. (14) This note carries an interest rate that, upon assumption, was below market rates and it therefore was recorded at its fair value based on applicable effective interest rates. The carrying value of this note reflects an unamortized discount totaling $108,000 as of December 31, 2021 and $161,000 as of December 31, 2020.
Schedule of debt maturities	Our debt matures on the following schedule (in thousands): Year Ending December 31, December 31, 2021 2022 $ 303,333 2023 94,953 2024 29,983 2025 23,717 2026 446,300 Thereafter 1,400,000 Total $ 2,298,286 (1) (1) Represents scheduled principal amortization and maturities only and therefore excludes net discounts and deferred financing costs of $26.0 million.
Schedule of the fair value of debt	The following table sets forth information pertaining to the fair value of our debt (in thousands): December 31, 2021 December 31, 2020 Carrying Estimated Carrying Estimated Fixed-rate debt Unsecured Senior Notes $ 1,775,504 $ 1,809,950 $ 1,289,461 $ 1,334,342 Other fixed-rate debt 87,713 87,339 140,891 142,838 Variable-rate debt 409,087 409,639 656,566 654,102 $ 2,272,304 $ 2,306,928 $ 2,086,918 $ 2,131,282

Interest Rate Derivatives (Tabl

Interest Rate Derivatives (Tables)	12 Months Ended
	Dec. 31, 2021
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of key terms and fair values of interest rate swap derivatives	The following table sets forth the key terms and fair values of our interest rate swap derivatives (dollars in thousands): Notional Amount Effective Date Expiration Date Fair Value at December 31, Fixed Rate Floating Rate Index 2021 2020 $ 100,000 1.901 % One-Month LIBOR 9/1/2016 12/1/2022 $ (1,361) $ (3,394) $ 100,000 1.905 % One-Month LIBOR 9/1/2016 12/1/2022 (1,365) (3,401) $ 50,000 (1) 1.908 % One-Month LIBOR 9/1/2016 12/1/2022 (684) (1,704) $ 11,120 (2) 1.678 % One-Month LIBOR 8/1/2019 8/1/2026 (234) (733) $ 23,000 (3) 0.573 % One-Month LIBOR 4/1/2020 3/26/2025 355 (290) $ (3,289) $ (9,522) (1) Refer to additional disclosure below. (2) The notional amount of this instrument is scheduled to amortize to $10.0 million. (3) 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 December 31, Derivatives Balance Sheet Location 2021 2020 Interest rate swaps designated as cash flow hedges Prepaid expenses and other assets, net $ 355 $ — Interest rate swaps designated as cash flow hedges Interest rate derivatives (liabilities) $ (2,960) $ (9,522) Interest rate swap not designated Interest rate derivatives (liabilities) $ (684) $ —
Schedule of effect of interest rate derivatives on consolidated statements of operations and comprehensive income	The tables below presents the effect of our interest rate derivatives on our consolidated statements of operations and comprehensive income (in thousands): Amount of Income (Loss) Recognized in AOCL on Derivatives Amount of (Loss) Gain Reclassified from AOCL into Interest Expense on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2021 2020 2019 2021 2020 2019 Interest rate derivatives $ 1,379 $ (39,454) $ (24,321) $ (5,048) $ (3,725) $ 1,415 Amount of Loss Reclassified from AOCL into Loss on Interest Rate Derivatives on Statement of Operations Amount of Loss Recognized on Undesignated Swaps in Loss on Interest Rate Derivatives on Statement of Operations For the Years Ended December 31, For the Years Ended December 31, Derivatives in Hedging Relationships 2021 2020 2019 2021 2020 2019 Interest rate derivatives $ — $ (51,865) $ — $ — $ (1,265) $ —

Redeemable Noncontrolling Int_2

Redeemable Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2021
Noncontrolling Interest [Abstract]
Schedule of activity for redeemable noncontrolling interest	The table below sets forth the activity for these redeemable noncontrolling interests (in thousands): For the Years Ended December 31, 2021 2020 2019 Beginning balance $ 25,430 $ 29,431 $ 26,260 Distributions to noncontrolling interests (3,307) (14,034) (2,413) Net income attributable to noncontrolling interests 3,160 3,426 3,835 Adjustment to arrive at fair value of interests 1,615 6,607 1,749 Ending balance $ 26,898 $ 25,430 $ 29,431

Share-Based Compensation and _2

Share-Based Compensation and Other Compensation Matters (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payment Arrangement [Abstract]
Reporting for share-based compensation expense	The table below sets forth our reporting for share based compensation cost (in thousands): For the Years Ended December 31, 2021 2020 2019 General, administrative and leasing expenses $ 6,881 $ 5,385 $ 5,748 Property operating expenses 1,098 1,119 966 Capitalized to development activities 719 556 742 Share-based compensation cost $ 8,698 $ 7,060 $ 7,456
Summary of restricted share and TB-PIU transactions under the entity's share-based compensation plans	The following table summarizes restricted shares under the share-based compensation plans for 2019, 2020 and 2021: Shares Weighted Average Grant Date Fair Value Unvested as of December 31, 2018 438,685 $ 28.38 Granted 195,520 $ 26.56 Forfeited (56,341) $ 29.44 Vested (185,001) $ 28.01 Unvested as of December 31, 2019 392,863 $ 27.49 Granted 166,918 $ 25.22 Forfeited (25,773) (1) $ 27.12 Vested (173,191) $ 28.14 Unvested as of December 31, 2020 360,817 $ 26.16 Granted 177,995 $ 26.17 Forfeited (39,664) $ 26.62 Vested (164,575) $ 25.95 Unvested as of December 31, 2021 334,573 $ 26.22 Unvested shares as of December 31, 2021 that are expected to vest 306,658 $ 26.22 (1) Includes 9,064 restricted shares previously awarded to our former Executive Vice President and Chief Operating Officer that were forfeited upon his resignation. 2021 : Number of TB-PIUs Weighted Average Grant Date Fair Value Unvested as of December 31, 2018 — N/A Granted 61,820 $ 26.01 Unvested as of December 31, 2019 61,820 $ 26.01 Granted 98,318 $ 25.47 Forfeited (20,622) (1) $ 25.50 Vested (25,182) $ 26.30 Unvested as of December 31, 2020 114,334 $ 25.57 Granted 93,983 $ 26.16 Vested (45,244) $ 25.28 Unvested as of December 31, 2021 163,073 $ 25.99 Unvested TB-PIUs as of December 31, 2021 that are expected to vest 162,472 $ 25.99 (1) Represents TB-PIUs previously awarded to our former Executive Vice President and Chief Operating Officer that were forfeited upon his resignation.
Schedule of PB-PIU/PSUs Granted	We made the following grants of PB-PIUs to executives in 2019, 2020 and 2021 (dollars in thousands, except per share data): Grant Date Number of PB-PIUs Granted Grant Date Fair Value Number of PB-PIUs Outstanding as of December 31, 2021 (1) 1/1/2019 193,682 $ 2,415 156,104 1/1/2020 176,758 $ 2,891 141,152 1/1/2021 227,544 $ 3,417 227,544 (1) Excludes 73,184 PB-PIUs previously awarded to our former Executive Vice President and Chief Operating Officer that were forfeited upon his resignation. As of December 31, 2021, we had no PSU grants outstanding. Below is information for executive grants of PSUs with performance periods included in these consolidated financial statements (dollars in thousands): Grant Date Number of PSUs Granted Grant Date Fair Value 1/1/2017 39,351 $ 1,415 1/1/2018 59,110 $ 1,890
Schedule of payouts for defined performance under PB-PIU/PSUs	The number of earned awards at the end of the performance period will be determined based on the percentile rank of COPT’s total shareholder return (“TSR”) relative to a peer group of companies, as set forth in the following schedule: Percentile Rank Earned Awards Payout % 75th or greater 100% of PB-PIUs granted 50th (target) 50% of PB-PIUs granted 25th 25% of PB-PIUs granted Below 25th 0% of PB-PIUs granted Percentile Rank Earned PSUs Payout % 75th or greater 200% of PSUs granted 50th (target) 100% of PSUs granted 25th 50% of PSUs granted Below 25th 0% of PSUs granted
Schedule of assumptions used in Monte Carlo models for PB-PIUs	The grant date fair value and certain of the assumptions used in the Monte Carlo models for the PB-PIUs granted in 2019, 2020 and 2021 are set forth below: Grant Date Grant Date Fair Value Per PB-PIU at Target-Level Award Baseline Common Share Value Expected Volatility of Common Shares Risk-free Interest Rate 1/1/2019 $ 24.94 $ 21.03 21.0 % 2.51 % 1/1/2020 $ 32.71 $ 29.38 18.0 % 1.65 % 1/1/2021 $ 30.03 $ 26.08 34.7 % 0.18 %
Deferred Shares Granted	We made the following grants of deferred share awards to non-employee Trustees in 2019, 2020 and 2021 (dollars in thousands, except per share data): Year of Grant Number of Deferred Share Awards Granted Aggregate Grant Date Fair Value Grant Date Fair Value Per Award 2019 3,432 $ 95 $ 27.60 2020 10,679 $ 253 $ 23.68 2021 3,416 $ 93 $ 27.12

Credit Losses, Financial Asse_2

Credit Losses, Financial Assets and Other Instruments (Tables)	12 Months Ended
	Dec. 31, 2021
Credit Loss [Abstract]
Schedule of Credit Losses, Financial Assets and Other Instruments, Allowance for Credit Loss	The table below sets forth the activity for the allowance for credit losses (in thousands): For the Years Ended December 31, 2020 and 2021 Investing Receivables Tenant Notes Other Assets (2) Off-Balance Sheet Credit Exposures Total December 31, 2019 $ — $ 97 $ — $ — $ 97 Cumulative effect of change for adoption of credit loss guidance 3,732 325 144 1,340 5,541 Credit loss (recoveries) expense (881) 729 559 (1,340) (933) Other changes — 52 (60) — (8) December 31, 2020 2,851 1,203 643 — 4,697 Credit loss (recoveries) expense (1,252) (146) 270 — (1,128) December 31, 2021 $ 1,599 $ 1,057 $ 913 $ — $ 3,569 (1) Included in the line entitled “accounts receivable, net” on our consolidated balance sheets. (2) The balance as of December 31, 2021 and December 31, 2020 included $218,000 and $257,000, respectively, in the line entitled “accounts receivable, net” and $695,000 and $386,000, respectively, in the line entitled “prepaid expenses and other assets, net” on our consolidated balance sheets.
Financing Receivable Credit Quality Indicators	The following table presents the amortized cost basis of our investing receivables, tenants notes receivable and sales-type lease receivables by credit risk classification, by origination year as of December 31, 2021 (in thousands): Origination Year 2016 and Earlier 2017 2018 2019 2020 2021 Total Investing receivables: Credit risk classification: Investment grade $ 70,434 $ 1,069 $ — $ — $ 1,675 $ 4,606 $ 77,784 Non-investment grade — — — 6,041 — — 6,041 Total $ 70,434 $ 1,069 $ — $ 6,041 $ 1,675 $ 4,606 $ 83,825 Tenant notes receivable: Credit risk classification: Investment grade $ — $ — $ 921 $ 63 $ 271 $ — $ 1,255 Non-investment grade 207 — 132 137 1,724 — 2,200 Total $ 207 $ — $ 1,053 $ 200 $ 1,995 $ — $ 3,455 Sales-type lease receivable: Credit risk classification: Investment grade $ — $ — $ — $ — $ 6,194 $ — $ 6,194

Information by Business Segme_2

Information by Business Segment (Tables)	12 Months Ended
	Dec. 31, 2021
Segment Reporting [Abstract]
Schedule of segment financial information for real estate operations	The table below reports segment financial information for our reportable segments (in thousands): Defense/IT Locations Fort Meade/BW Corridor NoVA Defense/IT Lackland Air Force Base Navy Support Redstone Arsenal Data Center Shells Total Defense/IT Locations Regional Office Wholesale Other Total Year Ended December 31, 2021 Revenues from real estate operations $ 262,120 $ 62,390 $ 57,756 $ 33,757 $ 35,727 $ 31,582 $ 483,332 $ 66,570 $ 30,490 $ 6,668 $ 587,060 Property operating expenses (92,521) (23,218) (30,535) (13,617) (11,618) (4,086) (175,595) (32,623) (17,424) (4,577) (230,219) UJV NOI allocable to COPT — — — — — 4,029 4,029 — — — 4,029 NOI from real estate operations $ 169,599 $ 39,172 $ 27,221 $ 20,140 $ 24,109 $ 31,525 $ 311,766 $ 33,947 $ 13,066 $ 2,091 $ 360,870 Additions to long-lived assets $ 45,647 $ 5,823 $ — $ 4,193 $ 3,542 $ — $ 59,205 $ 35,412 $ 1,680 $ 488 $ 96,785 Transfers from non-operating properties $ 70,514 $ 90,050 $ 59,323 $ — $ 22,739 $ 3,004 $ 245,630 $ 39,319 $ — $ — $ 284,949 Segment assets at December 31, 2021 $ 1,332,399 $ 471,760 $ 198,200 $ 170,985 $ 300,252 $ 350,098 $ 2,823,694 $ 555,090 $ 192,647 $ 4,031 $ 3,575,462 Year Ended December 31, 2020 Revenues from real estate operations $ 254,197 $ 57,817 $ 50,982 $ 32,869 $ 22,515 $ 29,139 $ 447,519 $ 60,627 $ 27,011 $ 3,568 $ 538,725 Property operating expenses (85,032) (21,321) (29,055) (12,655) (8,119) (3,195) (159,377) (29,144) (13,543) (1,776) (203,840) UJV NOI allocable to COPT — — — — — 6,951 6,951 — — — 6,951 NOI from real estate operations $ 169,165 $ 36,496 $ 21,927 $ 20,214 $ 14,396 $ 32,895 $ 295,093 $ 31,483 $ 13,468 $ 1,792 $ 341,836 Additions to long-lived assets $ 31,295 $ 11,620 $ — $ 7,104 $ 2,905 $ — $ 52,924 $ 17,232 $ 10,856 $ 467 $ 81,479 Transfers from non-operating properties $ 21,859 $ 2,557 $ 456 $ — $ 138,122 $ 230,277 $ 393,271 $ 83,091 $ — $ — $ 476,362 Segment assets at December 31, 2020 $ 1,277,849 $ 392,714 $ 142,137 $ 178,897 $ 281,386 $ 419,929 $ 2,692,912 $ 490,422 $ 201,820 $ 3,824 $ 3,388,978 Year Ended December 31, 2019 Revenues from real estate operations $ 252,781 $ 55,742 $ 51,140 $ 32,659 $ 16,593 $ 26,571 $ 435,486 $ 59,611 $ 29,405 $ 2,961 $ 527,463 Property operating expenses (82,815) (19,779) (29,042) (13,579) (6,626) (1,962) (153,803) (29,682) (13,213) (1,445) (198,143) UJV NOI allocable to COPT — — — — — 5,705 5,705 — — — 5,705 NOI from real estate operations $ 169,966 $ 35,963 $ 22,098 $ 19,080 $ 9,967 $ 30,314 $ 287,388 $ 29,929 $ 16,192 $ 1,516 $ 335,025 Additions to long-lived assets $ 34,618 $ 9,326 $ — $ 8,912 $ 1,548 $ — $ 54,404 $ 20,925 $ 893 $ 128 $ 76,350 Transfers from non-operating properties $ 18,606 $ 4,548 $ 10,781 $ — $ 33,606 $ 159,472 $ 227,013 $ — $ (1,012) $ — $ 226,001 Segment assets at December 31, 2019 $ 1,280,656 $ 396,914 $ 146,592 $ 184,257 $ 138,501 $ 279,099 $ 2,426,019 $ 392,319 $ 202,935 $ 3,685 $ 3,024,958
Schedule of reconciliation of segment revenues to total revenues	The following table reconciles our segment revenues to total revenues as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 Segment revenues from real estate operations $ 587,060 $ 538,725 $ 527,463 Construction contract and other service revenues 107,876 70,640 113,763 Less: Revenues from discontinued operations (Note 4) (30,490) (27,011) (29,405) Total revenues $ 664,446 $ 582,354 $ 611,821
Schedule of reconciliation of segment property operating expenses to property operating expenses	The following table reconciles our segment property operating expenses to property operating expenses as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 Segment property operating expenses $ 230,219 $ 203,840 $ 198,143 Less: Property operating expenses from discontinued operations (Note 4) (16,842) (13,044) (12,694) Total property operating expenses $ 213,377 $ 190,796 $ 185,449
Reconciliation of UJV NOI allocable to COPT to equity in income of unconsolidated entities	The following table reconciles UJV NOI allocable to COPT to equity in income of unconsolidated entities as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 UJV NOI allocable to COPT $ 4,029 $ 6,951 $ 5,705 Less: Income from UJVs allocable to COPT attributable to depreciation and amortization expense and interest expense (2,930) (5,120) (4,065) Add: Equity in loss of unconsolidated non-real estate entities (6) (6) (7) Equity in income of unconsolidated entities $ 1,093 $ 1,825 $ 1,633
Schedule of computation of net operating income from service operations	The table below sets forth the computation of our NOI from service operations (in thousands): For the Years Ended December 31, 2021 2020 2019 Construction contract and other service revenues $ 107,876 $ 70,640 $ 113,763 Construction contract and other service expenses (104,053) (67,615) (109,962) NOI from service operations $ 3,823 $ 3,025 $ 3,801
Schedule of reconciliation of net operating income from real estate operations and service operations to income from continuing operations	The following table reconciles our NOI from real estate operations for reportable segments and NOI from service operations to income from continuing operations as reported on our consolidated statements of operations (in thousands): For the Years Ended December 31, 2021 2020 2019 NOI from real estate operations $ 360,870 $ 341,836 $ 335,025 NOI from service operations 3,823 3,025 3,801 Interest and other income 7,879 8,574 7,894 Credit loss recoveries 1,128 933 — Gain on sales of real estate 65,590 30,209 105,230 Gain on sale of investment in unconsolidated real estate joint venture — 29,416 — Equity in income of unconsolidated entities 1,093 1,825 1,633 Income tax (expense) benefit (145) (353) 217 Depreciation and other amortization associated with real estate operations (137,543) (126,503) (125,008) Impairment losses — (1,530) (329) General, administrative and leasing expenses (36,127) (33,001) (35,402) Business development expenses and land carry costs (4,647) (4,473) (4,239) Interest expense (65,398) (67,937) (71,052) UJV NOI allocable to COPT included in equity in income of unconsolidated entities (4,029) (6,951) (5,705) Revenues from real estate operations from discontinued operations (Note 4) (30,490) (27,011) (29,405) Property operating expenses from discontinued operations (Note 4) 16,842 13,044 12,694 Loss on early extinguishment of debt (100,626) (7,306) — Loss on interest rate derivatives — (53,196) — Income from continuing operations $ 78,220 $ 100,601 $ 195,354
Schedule of reconciliation of segment assets to total assets	The following table reconciles our segment assets to our consolidated total assets (in thousands): As of December 31, 2021 2020 Segment assets $ 3,575,462 $ 3,388,978 Operating properties lease liabilities included in segment assets 29,342 30,721 Non-operating property assets 449,144 466,991 Other assets 208,504 190,333 Total consolidated assets $ 4,262,452 $ 4,077,023

Construction Contract and Oth_2

Construction Contract and Other Service Revenues (Tables)	12 Months Ended
	Dec. 31, 2021
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The table below reports construction contract and other service revenues by compensation arrangement (in thousands): For the Years Ended December 31, 2021 2020 2019 Construction contract revenue: GMP $ 68,113 $ 22,032 $ 67,708 Cost-plus fee 24,260 34,025 34,386 FFP 13,897 12,373 10,688 Other 1,606 2,210 981 $ 107,876 $ 70,640 $ 113,763 The table below reports construction contract and other service revenues by service type (in thousands): For the Years Ended December 31, 2021 2020 2019 Construction contract revenue: Construction $ 104,020 $ 66,087 $ 112,170 Design 2,250 2,343 612 Other 1,606 2,210 981 $ 107,876 $ 70,640 $ 113,763
Contract Asset, Contract Liability and Receivable	Accounts receivable related to our construction contract services is included in accounts receivable, net on our consolidated balance sheets. The beginning and ending balances of accounts receivable related to our construction contracts were as follows (in thousands): For the Years Ended December 31, 2021 2020 Beginning balance $ 13,997 $ 12,378 Ending balance $ 7,193 $ 13,997 Contract assets, which we refer to herein as construction contract costs in excess of billings, net, are included in prepaid expenses and other assets, net on our consolidated balance sheets. The beginning and ending balances of our contract assets were as follows (in thousands): For the Years Ended December 31, 2021 2020 Beginning balance $ 10,343 $ 17,223 Ending balance $ 22,384 $ 10,343 Contract liabilities are included in other liabilities on our consolidated balance sheets. Changes in contract liabilities were as follows (in thousands): For the Years Ended December 31, 2021 2020 Beginning balance $ 4,610 $ 1,184 Ending balance $ 2,499 $ 4,610 Portion of beginning balance recognized in revenue during the year $ 2,664 $ 757

Earnings Per Share ("EPS") (Tab

Earnings Per Share ("EPS") (Tables)	12 Months Ended
	Dec. 31, 2021
Earnings Per Share [Abstract]
Summary of calculation of numerator and denominator in basic and diluted earnings per share	Summaries of the numerator and denominator for purposes of basic and diluted EPS calculations are set forth below (in thousands, except per share data): For the Years Ended December 31, 2021 2020 2019 Numerator: Income from continuing operations $ 78,220 $ 100,601 $ 195,354 Income from continuing operations attributable to noncontrolling interests (4,994) (5,477) (8,255) Income from continuing operations attributable to share-based compensation awards for basic EPS (467) (433) (638) Numerator for basic EPS from continuing operations attributable to COPT common shareholders $ 72,759 $ 94,691 $ 186,461 Redeemable noncontrolling interests (128) — 132 Adjustment to income from continuing operations attributable to share-based compensation awards for diluted EPS 44 27 33 Numerator for diluted EPS from continuing operations attributable to COPT common shareholders $ 72,675 $ 94,718 $ 186,626 Discontinued operations 3,358 2,277 4,650 Discontinued operations attributable to noncontrolling interests (43) (27) (57) Income from discontinued operations attributable to share-based compensation awards for diluted EPS 6 2 (18) Numerator for diluted EPS on net income attributable to COPT common shareholders $ 75,996 $ 96,970 $ 191,201 Denominator (all weighted averages): Denominator for basic EPS (common shares) 111,960 111,788 111,196 Dilutive effect of redeemable noncontrolling interests 128 — 119 Dilutive effect of share-based compensation awards 330 288 308 Denominator for diluted EPS (common shares) 112,418 112,076 111,623 Basic EPS: Income from continuing operations attributable to COPT common shareholders $ 0.65 $ 0.85 $ 1.68 Discontinued operations attributable to COPT common shareholders 0.03 0.02 0.04 Net income attributable to COPT common shareholders $ 0.68 $ 0.87 $ 1.72 Diluted EPS: Income from continuing operations attributable to COPT common shareholders $ 0.65 $ 0.85 $ 1.67 Discontinued operations attributable to COPT common shareholders 0.03 0.02 0.04 Net income attributable to COPT common shareholders $ 0.68 $ 0.87 $ 1.71
Schedule of securities excluded from computation of diluted earnings per share	Our diluted EPS computations do not include the effects of the following securities since the conversions of such securities would increase diluted EPS for the respective periods (in thousands): Weighted Average Shares Excluded from Denominator for the Years Ended December 31, 2021 2020 2019 Conversion of common units 1,257 1,236 1,299 Conversion of redeemable noncontrolling interests 804 957 896 Conversion of Series I Preferred Units — 171 176

Quarterly Data (Unaudited) (Tab

Quarterly Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Schedule of selected quarterly information	The tables below set forth selected quarterly information for the years ended December 31, 2021 and 2020 (in thousands, except per share/unit data). 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, including amounts reclassified in conjunction with the transfer of our wholesale data center to discontinued operations in December 2021. For the Year Ended December 31, 2021 For the Year Ended December 31, 2020 First Quarter Second Quarter Third Quarter Fourth Quarter First Quarter Second Quarter Third Quarter Fourth Quarter Revenues $ 154,388 $ 157,207 $ 166,919 $ 185,932 $ 138,625 $ 138,321 $ 148,801 $ 156,607 (Loss) income from continuing operations $ (6,894) $ 43,219 $ 28,343 $ 13,552 $ 24,426 $ 24,984 $ (30,991) $ 82,182 Discontinued operations 815 679 451 1,413 1,124 137 (351) 1,367 Net (loss) income $ (6,079) $ 43,898 $ 28,794 $ 14,965 $ 25,550 $ 25,121 $ (31,342) $ 83,549 Net loss (income) attributable noncontrolling interests (590) (1,497) (1,693) (1,257) (1,496) (1,624) (503) (1,881) Net (loss) income attributable to COPT common shareholders $ (6,669) $ 42,401 $ 27,101 $ 13,708 $ 24,054 $ 23,497 $ (31,845) $ 81,668 Basic EPS $ (0.06) $ 0.38 $ 0.24 $ 0.12 $ 0.21 $ 0.21 $ (0.29) $ 0.73 Diluted EPS $ (0.06) $ 0.38 $ 0.24 $ 0.12 $ 0.21 $ 0.21 $ (0.29) $ 0.73

Organization (Narrative) (Detai

Organization (Narrative) (Details) - 12 months ended Dec. 31, 2021 ft² in Millions	property	ft²	a	MW	shares
Corporate Office Properties, L.P | COPT | Preferred units
Investments in real estate
Limited partners' capital account, units outstanding (in shares) | shares					0
Common Units | Corporate Office Properties, L.P | COPT
Investments in real estate
Percentage ownership in operating partnership	98.30%
Operating properties
Investments in real estate
Number of real estate properties	186
Area of real estate property (in sqft or acres) | ft²		21.7
Operating properties | Office Properties
Investments in real estate
Number of real estate properties	160
Area of real estate property (in sqft or acres) | ft²		17
Operating properties | Single-tenant data centers
Investments in real estate
Number of real estate properties	26
Area of real estate property (in sqft or acres) | ft²		4.7
Wholesale Data Center
Investments in real estate
Capacity (in megawatts) | MW				19.25
Properties under development
Investments in real estate
Number of real estate properties	11
Area of real estate property (in sqft or acres) | ft²		1.7
Properties under development | Office Properties
Investments in real estate
Number of real estate properties	8
Properties under development | Single-tenant data centers
Investments in real estate
Number of real estate properties	3
Properties Under Development, Partially-Operational
Investments in real estate
Number of real estate properties	1
Land controlled for future development
Investments in real estate
Area of real estate property (in sqft or acres)		8.9	720
Other land
Investments in real estate
Area of real estate property (in sqft or acres) | a			43
Unconsolidated Real Estate Joint Ventures
Investments in real estate
Number of real estate properties	19
Unconsolidated Real Estate Joint Ventures | Operating properties | Single-tenant data centers
Investments in real estate
Number of real estate properties	19

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Properties and Impairment) (Details)	12 Months Ended
	Dec. 31, 2021
Properties
Period after the cessation of major construction activities for considering property as operational if leases have not commenced earlier (in years)	1 year
Period after the cessation of major construction activities for considering property as partially operational if leases have commenced earlier (in years)	1 year
Property, Plant and Equipment [Line Items]
Period used recovery analysis for long-lived assets to be held and used that may be impaired (in years)	10 years
Minimum | Buildings and building improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Minimum | Land improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years
Minimum | Equipment and personal property
Property, Plant and Equipment [Line Items]
Estimated useful life	3 years
Maximum | Buildings and building improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	40 years
Maximum | Land improvements
Property, Plant and Equipment [Line Items]
Estimated useful life	20 years
Maximum | Equipment and personal property
Property, Plant and Equipment [Line Items]
Estimated useful life	10 years

Summary of Significant Accoun_5

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

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Revenue Recognition) (Details)	Dec. 31, 2021
United States Government
Lessor, Lease, Description [Line Items]
Renewal term	1 year

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Share-Based Compensation) (Details)	12 Months Ended
	Dec. 31, 2021form
Accounting Policies [Abstract]
Number of forms of share based compensation plans	4

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Income Taxes) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Tax Disclosure [Line Items]
Approximate amount by which basis of assets and liabilities for tax reporting purposes is higher (lower) than amount reported on consolidated balance sheet	$ 18
Common Shares
Income Tax Disclosure [Line Items]
Ordinary income	33.30%	45.10%	54.40%
Long-term capital gain	57.30%	54.90%	45.60%
Return of capital	9.40%	0.00%	0.00%

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2021	Dec. 31, 2020
Assets and liabilities measured at fair value on a recurring basis
Marketable securities in deferred compensation plan		$ 2,556	$ 3,027
Fair Value, Recurring | Deferred compensation plan | Trustees and Management
Assets and liabilities measured at fair value on a recurring basis
Maximum percentage of participants' compensation which is deferrable (as a percent)	100.00%
Marketable securities in deferred compensation plan		$ 2,600	$ 3,000

Fair Value Measurements (Recurr

Fair Value Measurements (Recurring Basis) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets:
Marketable securities in deferred compensation plan	$ 2,556	$ 3,027
Fair value measurement on a recurring basis
Assets:
Other marketable securities	33	30
Interest rate derivatives	355
Total assets	2,944	3,057
Liabilities:
Deferred compensation plan liability	2,556	3,027
Interest rate derivatives	3,644	9,522
Total liabilities	6,200	12,549
Fair value measurement on a recurring basis | Mutual funds
Assets:
Marketable securities in deferred compensation plan	2,485	3,008
Fair value measurement on a recurring basis | Other
Assets:
Marketable securities in deferred compensation plan	71	19
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Other marketable securities	33	30
Interest rate derivatives	0
Total assets	2,589	3,057
Liabilities:
Deferred compensation plan liability	0	0
Interest rate derivatives	0	0
Total liabilities	0	0
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Mutual funds
Assets:
Marketable securities in deferred compensation plan	2,485	3,008
Fair value measurement on a recurring basis | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other
Assets:
Marketable securities in deferred compensation plan	71	19
Fair value measurement on a recurring basis | Significant Other Observable Inputs(Level 2)
Assets:
Other marketable securities	0	0
Interest rate derivatives	355
Total assets	355	0
Liabilities:
Deferred compensation plan liability	2,556	3,027
Interest rate derivatives	3,644	9,522
Total liabilities	6,200	12,549
Fair value measurement on a recurring basis | Significant Other Observable Inputs(Level 2) | Mutual funds
Assets:
Marketable securities in deferred compensation plan	0	0
Fair value measurement on a recurring basis | Significant Other Observable Inputs(Level 2) | Other
Assets:
Marketable securities in deferred compensation plan	0	0
Fair value measurement on a recurring basis | Significant Unobservable  Inputs (Level 3)
Assets:
Other marketable securities	0	0
Interest rate derivatives	0
Total assets	0	0
Liabilities:
Deferred compensation plan liability	0	0
Interest rate derivatives	0	0
Total liabilities	0	0
Fair value measurement on a recurring basis | Significant Unobservable  Inputs (Level 3) | Mutual funds
Assets:
Marketable securities in deferred compensation plan	0	0
Fair value measurement on a recurring basis | Significant Unobservable  Inputs (Level 3) | Other
Assets:
Marketable securities in deferred compensation plan	$ 0	$ 0

Properties, Net (Operating prop

Properties, Net (Operating properties, net) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating properties, net
Gross	$ 4,959,709	$ 4,686,802	$ 4,348,006	$ 4,148,529
Operating properties, net	3,090,510	2,915,016
Operating properties, net
Operating properties, net
Less: accumulated depreciation	(1,152,523)	(1,052,007)
Operating properties, net	3,090,510	2,915,016
Operating properties, net | Land
Operating properties, net
Gross	572,900	522,219
Operating properties, net | Buildings and improvements
Operating properties, net
Gross	$ 3,670,133	$ 3,444,804

Properties, Net (Schedule of As

Properties, Net (Schedule of Assets Held for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets held for sale, net	$ 192,699	$ 201,820
Discontinued Operations, Held-for-sale | Wholesale Data Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Properties, net	191,857	200,264
Deferred rent receivable	462	1,025
Intangible assets on property acquisitions, net	73	95
Deferred leasing costs, net	307	436
Assets held for sale, net	$ 192,699	$ 201,820

Properties, Net (Components of

Properties, Net (Components of Discontinued Operations) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from real estate operations									$ 30,490	$ 27,011	$ 29,405
Property operating expenses									(16,842)	(13,044)	(12,694)
Discontinued operations	$ 1,413	$ 451	$ 679	$ 815	$ 1,367	$ (351)	$ 137	$ 1,124	3,358	2,277	4,650
Discontinued Operations, Held-for-sale | Wholesale Data Center
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues from real estate operations									30,490	27,011	29,405
Property operating expenses									(16,842)	(13,044)	(12,694)
Depreciation and amortization associated with real estate operations									(10,290)	(11,690)	(12,061)
Discontinued operations									3,358	2,277	4,650
Cash flows from operating activities									10,930	16,051	18,626
Cash flows from investing activities									$ (1,912)	$ (11,485)	$ (805)

Properties, Net (Narrative) (De

Properties, Net (Narrative) (Details) ft² in Thousands, $ in Millions	Dec. 30, 2021USD ($)	Jun. 02, 2021USD ($)property	Oct. 30, 2020USD ($)property	Sep. 30, 2020USD ($)	Dec. 31, 2021USD ($)ft²property	Dec. 31, 2020USD ($)ft²property	Dec. 31, 2019USD ($)ft²property	Dec. 22, 2020	Dec. 05, 2019property	Jun. 20, 2019property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage sold					90.00%	90.00%	90.00%
Number of properties sold					2	2	9
BRE-COPT 3
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %		10.00%			10.00%
Number of real estate properties					2
BRE-COPT 2
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %			10.00%		10.00%	10.00%		10.00%
Number of real estate properties					8
BREIT-COPT
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Nominal Ownership %					10.00%		10.00%
Number of real estate properties					9
Baltimore, Maryland
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Impairment charges | $				$ 1.5
Newly-developed properties placed in service
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²					766	1,800	1,100
Number of real estate properties					8	11	9
Properties under development
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²					1,700
Number of real estate properties					11
Properties Under Development, Partially-Operational
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties					1
Expansion of Fully-Operational Properties Placed in Service
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²						42
Number of real estate properties						3
Redeveloped Property Placed in Service
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of real estate property (in sqft or acres) | ft²						21	85
Number of real estate properties							1
Data Center Shells in Northern Virginia | Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Ownership percentage sold		90.00%	90.00%				90.00%
Number of properties sold		2	2				9		2	7
Transaction value | $		$ 118.8	$ 89.7				$ 345.1
Proceeds from sale | $		$ 106.9	$ 80.7				310.6
Gain on disposal | $					$ 40.2	$ 30	$ 105.2
Other Data Center Shells | Disposed of by sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale | $	$ 30
Gain on disposal | $	$ 25.9

Leases (Lease Revenue) (Details

Leases (Lease Revenue) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Fixed	$ 436,768	$ 404,244	$ 392,341
Variable	116,900	104,870	100,824
Lease revenue	553,668	509,114	493,165
Discontinued Operations, Held-for-sale
Lessee, Lease, Description [Line Items]
Fixed	22,300	21,300	20,000
Variable	$ 8,200	$ 5,700	$ 9,300

Leases (Payments to be Received

Leases (Payments to be Received) (Details) $ in Thousands	Dec. 31, 2021USD ($)
Operating leases
2022	$ 430,910
2023	391,551
2024	344,256
2025	256,725
2026	193,051
Thereafter	939,463
Total contractual payments	2,555,956
Sales-type leases
2022	960
2023	960
2024	960
2025	960
2026	960
Thereafter	3,556
Total contractual payments	8,356
Less: Amount representing interest	(2,162)
Net investment in sales-type leases	$ 6,194

Leases (Percentage of Revenue)

Leases (Percentage of Revenue) (Details) - United States Government - Concentration risk	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lease Revenue From Continuing Operations, Risk Benchmark
Concentration Risk [Line Items]
Percentage of revenue	36.00%	37.00%	37.00%
Fixed Lease Revenue From Continuing Operations Benchmark
Concentration Risk [Line Items]
Percentage of revenue	26.00%	27.00%	27.00%

Leases (Lessee Arrangements) (D

Leases (Lessee Arrangements) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)Lease
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 40.6
Minimum | Land Leases
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	27 years
Maximum | Land Leases
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	79 years
Washington DC
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 9.9
Lessee, Remaining term of contract	78 years
Lessee, Number of lease contracts | Lease	2
Baltimore, Maryland
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 6.4
Lessee, Remaining term of contract	27 years
Optional renewal term	49 years
Phoenix, Arizona
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 5.1
Lessee, Remaining term of contract	3 years
Optional renewal term	5 years
LW Redstone Company, LLC | Huntsville, Alabama
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 10.9
Lessee, Number of lease contracts | Lease	16
Optional renewal term	25 years
LW Redstone Company, LLC | Huntsville, Alabama | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	41 years
LW Redstone Company, LLC | Huntsville, Alabama | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	50 years
M Square Associates, LLC | College Park, Maryland
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 6.1
Lessee, Number of lease contracts | Lease	4
M Square Associates, LLC | College Park, Maryland | Minimum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	61 years
M Square Associates, LLC | College Park, Maryland | Maximum
Lessee, Lease, Description [Line Items]
Lessee, Remaining term of contract	72 years
Fort Meade/BW Corridor
Lessee, Lease, Description [Line Items]
Lessee, Right-of-use asset	$ 2.2
Lessee, Remaining term of contract	46 years
Lessee, Number of lease contracts | Lease	2

Leases (Property right-of-use A

Leases (Property right-of-use Assets ) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating leases - Property	$ 38,361	$ 40,570
Finance leases - Property	2,238	40,425
Total right-of-use assets	40,599	80,995
Property - operating lease liabilities	29,342	30,746
Finance leases - Property	0	28
Total lease liabilities	$ 29,342	$ 30,774
Finance Lease, Liability, Statement of Financial Position [Extensible List]	Other liabilities	Other liabilities

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	Oct. 22, 2021USD ($)
Land
Lessee, Lease, Description [Line Items]
Carrying value of finance lease right of use asset acquired under bargain purchase option	$ 37.8

Leases (Weighted Average Terms

Leases (Weighted Average Terms and Discount Rates) (Details)	Dec. 31, 2021
Leases [Abstract]
Operating leases, Weighted average remaining lease term	51 years
Operating lease, Weighted average discount rate	7.16%

Leases (Property Lease Cost) (D

Leases (Property Lease Cost) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lease costs	$ 4,087	$ 2,574	$ 1,698
Property operating expenses
Lessee, Lease, Description [Line Items]
Property leases - fixed	4,011	2,413	1,664
Property leases - variable	45	127	4
Finance lease cost - amortization of property right-of-use assets	$ 31	$ 34	$ 30

Leases (Supplemental Cash Flow

Leases (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating cash flows for operating leases	$ 3,206	$ 1,694	$ 1,004
Financing cash flows for financing leases	$ 14	$ 674	$ 14

Leases (Lease Liabilities) (Det

Leases (Lease Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
December 31, 2021
2022	$ 3,297
2023	3,352
2024	3,403
2025	1,749
2026	1,530
Thereafter	122,448
Total lease payments	135,779
Less: Amount representing interest	(106,437)
Lease liability	$ 29,342	$ 30,746

Real Estate Joint Ventures (Con

Real Estate Joint Ventures (Consolidated Real Estate Joint Ventures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Consolidated Real Estate Joint Ventures [Line Items]
Total Assets	$ 4,262,452	$ 4,077,023
Total Liabilities	2,578,479	$ 2,357,881
LW Redstone Company, LLC
Consolidated Real Estate Joint Ventures [Line Items]
Preferred distributions of annual operating cash flows to partner	1,200
Variable Interest Entity, Primary Beneficiary
Consolidated Real Estate Joint Ventures [Line Items]
Total Assets	746,060
Encumbered Assets	150,384
Total Liabilities	$ 147,725
Variable Interest Entity, Primary Beneficiary | LW Redstone Company, LLC
Consolidated Real Estate Joint Ventures [Line Items]
Nominal Ownership %	85.00%
Total Assets	$ 478,739
Encumbered Assets	89,589
Total Liabilities	$ 93,730
Variable Interest Entity, Primary Beneficiary | Stevens Investors, LLC
Consolidated Real Estate Joint Ventures [Line Items]
Nominal Ownership %	95.00%
Total Assets	$ 165,806
Encumbered Assets	0
Total Liabilities	$ 1,406
Variable Interest Entity, Primary Beneficiary | M Square Associates, LLC
Consolidated Real Estate Joint Ventures [Line Items]
Nominal Ownership %	50.00%
Total Assets	$ 101,515
Encumbered Assets	60,795
Total Liabilities	$ 52,589

Real Estate Joint Ventures (Nar

Real Estate Joint Ventures (Narrative) (Details) $ in Thousands, ft² in Millions	Dec. 22, 2020USD ($)property	Dec. 31, 2021USD ($)ft²property	Dec. 31, 2020USD ($)property	Dec. 31, 2019USD ($)property	Jun. 02, 2021	Dec. 21, 2020	Oct. 30, 2020
Investments in real estate joint ventures
Ownership percentage sold		90.00%	90.00%	90.00%
Number of properties sold | property		2	2	9
Gain on sale of investment in unconsolidated real estate joint venture		$ 0	$ 29,416	$ 0
BRE-COPT 2
Investments in real estate joint ventures
Nominal Ownership %	10.00%	10.00%	10.00%				10.00%
BREIT-COPT
Investments in real estate joint ventures
Nominal Ownership %		10.00%		10.00%
BRE-COPT 3
Investments in real estate joint ventures
Nominal Ownership %		10.00%			10.00%
GI-COPT DC Partnership LLC
Investments in real estate joint ventures
Ownership interest sold of the original 50% owned	80.00%
Nominal Ownership %						50.00%
Proceeds from sale of investment in unconsolidated real estate joint venture	$ 60,000
Gain on sale of investment in unconsolidated real estate joint venture	$ 29,400
LW Redstone Company, LLC
Investments in real estate joint ventures
Partner's capital account upon formation		$ 9,000
Percentage of cumulative preferred returns of cash flows on partners' invested capital		13.50%
Percentage of cumulative preferred returns of cash flows on our invested capital		13.50%
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company		85.00%
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the entity's partners		15.00%
Number of years following construction commencement threshold achievement before partner's interest can be purchased at fair value		5 years
Construction commencement threshold (in square feet) | ft²		4.4
Construction commencement completed (in sqft) | ft²		2.3
LW Redstone Company, LLC | Maximum
Investments in real estate joint ventures
Infrastructure costs anticipated to be funded by entity for reimbursement by the City of Huntsville (in dollars)		$ 76,000
LW Redstone Company, LLC | Notes receivable from the City of Huntsville
Investments in real estate joint ventures
Infrastructure costs funded to date for reimbursement by the City of Huntsville		68,100
Stevens Investors, LLC | Construction Loan
Investments in real estate joint ventures
Related party transaction, amounts of transaction		112,000
Loans and leases receivable, related parties		$ 92,200
Stevens Investors, LLC | Construction Loan | London Interbank Offered Rate (LIBOR)
Investments in real estate joint ventures
Related party transaction, rate		2.35%
Stevens Investors, LLC | Maximum
Investments in real estate joint ventures
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company		85.00%
Stevens Investors, LLC | Minimum
Investments in real estate joint ventures
Percentage of residual distributable cash flows in excess of unpaid cumulative preferred returns and return of invested capital entitled to the company		60.00%
M Square Associates, LLC
Investments in real estate joint ventures
Percentage of residual amounts distributed to each member		50.00%
GI-COPT DC Partnership LLC | BRE-COPT 2
Investments in real estate joint ventures
Number of properties sold | property	6

Real Estate Joint Ventures (Unc

Real Estate Joint Ventures (Unconsolidated Real Estate Joint Ventures) (Details) $ in Thousands	Dec. 31, 2021USD ($)property	Jun. 02, 2021	Dec. 31, 2020USD ($)	Dec. 22, 2020	Oct. 30, 2020	Dec. 31, 2019
Unconsolidated Real Estate Joint Ventures
Schedule of Equity Method Investments [Line Items]
Number of real estate properties | property	19
Real estate equity method investments	$ 39,889		$ 29,303
BRE-COPT 2
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10.00%		10.00%	10.00%	10.00%
Number of real estate properties | property	8
Real estate equity method investments	$ 15,579		$ 15,988
Difference between the joint venture's cost basis and the entity's share of B RE COPT’s underlying equity in the net assets acquired from GI-COPT	$ 7,200		7,400
BREIT-COPT
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10.00%					10.00%
Number of real estate properties | property	9
Real estate equity method investments	$ 12,460		13,315
BRE-COPT 3
Schedule of Equity Method Investments [Line Items]
Nominal Ownership %	10.00%	10.00%
Number of real estate properties | property	2
Real estate equity method investments	$ 11,850		$ 0

Intangible Assets on Property_3

Intangible Assets on Property Acquisitions (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 198,724	$ 201,826
Accumulated Amortization	184,157	182,577
Net Carrying Amount	14,567	19,249
Amortization of the intangible assets	$ 4,700	8,000	$ 8,700
Weighted average amortization period of intangible assets	7 years
Estimated future amortization expense associated with the intangible asset categories for the next five years
2022	$ 3,200
2023	2,800
2024	2,200
2025	2,000
2026	1,300
In-place lease value
Intangible assets on real estate acquisitions
Gross Carrying Amount	125,591	128,693
Accumulated Amortization	118,983	120,010
Net Carrying Amount	$ 6,608	8,683
Weighted average amortization period of intangible assets	5 years
Tenant relationship value
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 58,082	58,082
Accumulated Amortization	50,701	48,163
Net Carrying Amount	$ 7,381	9,919
Weighted average amortization period of intangible assets	8 years
Above-market leases
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 13,718	13,718
Accumulated Amortization	13,435	13,380
Net Carrying Amount	$ 283	338
Weighted average amortization period of intangible assets	7 years
Other
Intangible assets on real estate acquisitions
Gross Carrying Amount	$ 1,333	1,333
Accumulated Amortization	1,038	1,024
Net Carrying Amount	$ 295	$ 309
Weighted average amortization period of intangible assets	21 years

Investing Receivables (Details)

Investing Receivables (Details) - Investing Receivables - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 83,825	$ 71,605
Allowance for credit losses	(1,599)	(2,851)	$ 0
Investing receivables, net	82,226	68,754
Notes receivable from the City of Huntsville
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	77,784	65,564
Other investing loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amortized cost basis	$ 6,041	$ 6,041

Investing Receivables (Narrativ

Investing Receivables (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Investing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable, fair value disclosure	$ 84	$ 73
Notes receivable from the City of Huntsville | LW Redstone Company, LLC
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	9.95%
Note receivable term	30 years
Other investing loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest rate	8.00%
Investing Receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accrued interest receivable, net of allowance for credit losses	$ 5.3	$ 4.8

Prepaid Expenses and Other As_3

Prepaid Expenses and Other Assets, Net (Prepaid Expenses and Other Assets, Net) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Prepaid Expense and Other Assets [Abstract]
Lease incentives, net	$ 51,486	$ 35,642
Construction contract costs in excess of billings, net	22,384	10,343
Prepaid expenses	20,058	19,690
Furniture, fixtures and equipment, net	9,599	10,433
Net investment in sales-type leases	6,194	6,573
Non-real estate equity investments	5,544	5,509
Restricted cash	4,054	3,664	$ 3,397	$ 3,884
Marketable securities in deferred compensation plan	2,556	3,027
Deferred tax asset, net	1,841	1,989
Deferred financing costs, net	1,314	2,439
Other assets	5,708	5,274
Total	$ 130,738	$ 104,583

Prepaid Expenses and Other As_4

Prepaid Expenses and Other Assets, Net (Deferred Tax Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Tax Credit Carryforward [Line Items]
Deferred tax asset, net	$ 1,841	$ 1,989
TRS
Tax Credit Carryforward [Line Items]
Operating loss carry forward	1,835	2,087
Property	30	103
Valuation allowance	(24)	(201)
Deferred tax asset, net	$ 1,841	$ 1,989

Debt, Net (Debt Schedule) (Deta

Debt, Net (Debt Schedule) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Nov. 17, 2021	Aug. 11, 2021	Mar. 11, 2021	Dec. 31, 2020	Sep. 17, 2020
Debt
Carrying Value	$ 2,272,304,000				$ 2,086,918,000
Revolving Credit Facility
Debt
Carrying Value	$ 76,000,000				143,000,000
Weighted average interest rate	1.20%
Term Loan Facility
Debt
Interest rate	1.10%
Carrying Value	$ 299,420,000				398,447,000
Unsecured note payable
Debt
Interest rate	0.00%
Carrying Value	$ 753,000				900,000
Unamortized discount included in carrying value	$ 108,000				161,000
London Interbank Offered Rate (LIBOR) | Revolving Credit Facility | Minimum
Debt
Variable rate, spread	0.775%
London Interbank Offered Rate (LIBOR) | Revolving Credit Facility | Maximum
Debt
Variable rate, spread	1.45%
London Interbank Offered Rate (LIBOR) | Term Loan Facility | Minimum
Debt
Variable rate, spread	1.00%
London Interbank Offered Rate (LIBOR) | Term Loan Facility | Maximum
Debt
Variable rate, spread	1.65%
Mortgage and other secured debt
Debt
Carrying Value	$ 120,627,000				255,110,000
Mortgage and other secured debt | Fixed rate mortgage debt
Debt
Carrying Value	$ 86,960,000				139,991,000
Unamortized premium included in carrying value					155,000
Weighted average interest rate	4.07%
Mortgage and other secured debt | Fixed rate mortgage debt | Minimum
Debt
Interest rate	3.82%
Mortgage and other secured debt | Fixed rate mortgage debt | Maximum
Debt
Interest rate	4.62%
Mortgage and other secured debt | Variable rate secured loans
Debt
Carrying Value	$ 33,667,000				115,119,000
Weighted average interest rate	1.62%
Mortgage and other secured debt | London Interbank Offered Rate (LIBOR) | Variable rate secured loans | Minimum
Debt
Variable rate, spread	1.45%
Mortgage and other secured debt | London Interbank Offered Rate (LIBOR) | Variable rate secured loans | Maximum
Debt
Variable rate, spread	1.55%
Senior Notes | 2.25%, $400,000 aggregate principal
Debt
Interest rate	2.25%
Debt instrument, face amount	$ 400,000,000					$ 400,000,000
Carrying Value	395,491,000				394,464,000
Unamortized discount included in carrying value	$ 3,600,000				4,500,000
Effective interest rate on debt	2.48%
Senior Notes | 2.00%, $400,000 aggregate principal
Debt
Interest rate	2.00%
Debt instrument, face amount	$ 400,000,000		$ 400,000,000
Carrying Value	396,512,000				0
Unamortized discount included in carrying value	$ 2,500,000
Effective interest rate on debt	2.09%
Senior Notes | 2.75%, $600,000 aggregate principal
Debt
Interest rate	2.75%
Debt instrument, face amount	$ 600,000,000			$ 600,000,000
Carrying Value	589,060,000				0
Unamortized discount included in carrying value	$ 9,500,000
Effective interest rate on debt	2.94%
Senior Notes | 2.90%, $400,000 aggregate principal
Debt
Interest rate	2.90%
Debt instrument, face amount	$ 400,000,000	$ 400,000,000
Carrying Value	394,441,000				0
Unamortized discount included in carrying value	$ 4,500,000
Effective interest rate on debt	3.01%
Senior Notes | 3.60%, $350,000 aggregate principal
Debt
Interest rate	3.60%
Debt instrument, face amount	$ 350,000,000
Carrying Value	$ 0				348,888,000
Unamortized discount included in carrying value					$ 781,000
Effective interest rate on debt					3.70%
Senior Notes | 5.25%, $250,000 aggregate principal
Debt
Interest rate	5.25%
Debt instrument, face amount	$ 250,000,000
Carrying Value	$ 0				$ 248,194,000
Unamortized discount included in carrying value					$ 1,600,000
Effective interest rate on debt					5.49%
Senior Notes | 5.00%, $300,000 aggregate principal
Debt
Interest rate	5.00%
Debt instrument, face amount	$ 300,000,000
Carrying Value	0				$ 297,915,000
Unamortized discount included in carrying value					$ 1,800,000
Effective interest rate on debt					5.15%
Loans Payable
Debt
Net deferred financing costs	$ 5,800,000				$ 5,900,000
Line of Credit | London Interbank Offered Rate (LIBOR) | Minimum | Revolving Credit Facility
Debt
Variable rate, spread	0.775%
Line of Credit | London Interbank Offered Rate (LIBOR) | Maximum | Revolving Credit Facility
Debt
Variable rate, spread	1.45%

Debt, Net (Debt Maturities) (De

Debt, Net (Debt Maturities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Schedule on basis of which debt matures
2022	$ 303,333
2023	94,953
2024	29,983
2025	23,717
2026	446,300
Thereafter	1,400,000
Total	2,298,286
Net discounts and deferred financing costs	26,000
Capitalized interest costs	$ 6,500	$ 12,100	$ 10,800

Debt, Net (Fair Value of Debt)

Debt, Net (Fair Value of Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Carrying Amount
Debt Instrument [Line Items]
Long-term debt	$ 2,272,304	$ 2,086,918
Carrying Amount | Unsecured Senior Notes
Debt Instrument [Line Items]
Long-term debt	1,775,504	1,289,461
Carrying Amount | Other fixed-rate debt
Debt Instrument [Line Items]
Long-term debt	87,713	140,891
Carrying Amount | Variable-rate debt
Debt Instrument [Line Items]
Long-term debt	409,087	656,566
Estimated Fair Value
Debt Instrument [Line Items]
Long-term debt	2,306,928	2,131,282
Estimated Fair Value | Unsecured Senior Notes
Debt Instrument [Line Items]
Long-term debt	1,809,950	1,334,342
Estimated Fair Value | Other fixed-rate debt
Debt Instrument [Line Items]
Long-term debt	87,339	142,838
Estimated Fair Value | Variable-rate debt
Debt Instrument [Line Items]
Long-term debt	$ 409,639	$ 654,102

Debt, Net (Narrative) (Details)

Debt, Net (Narrative) (Details)	Nov. 17, 2021USD ($)	Aug. 11, 2021USD ($)	Mar. 11, 2021USD ($)	Sep. 17, 2020USD ($)	Dec. 31, 2021USD ($)extension	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Nov. 18, 2021USD ($)	Apr. 12, 2021USD ($)	Oct. 19, 2020USD ($)
Debt Instrument [Line Items]
Loss on early extinguishment of debt					$ (100,626,000)	$ (7,306,000)	$ 0
Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average interest rate					1.20%
Aggregate additional borrowing capacity					$ 500,000,000
Term Loan Facility
Debt Instrument [Line Items]
Loan increase					150,000,000
Repayments of term loan					$ 100,000,000
Minimum | Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate, spread					0.775%
Minimum | Term Loan Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate, spread					1.00%
Maximum | Revolving Credit Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate, spread					1.45%
Maximum | Term Loan Facility | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate, spread					1.65%
Revolving Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average borrowings					$ 135,800,000	$ 204,900,000
Weighted average interest rate					1.18%	1.55%
Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity					$ 800,000,000
Maximum availability					$ 1,250,000,000
Number of extensions | extension					2
Extension option period					6 months
Line of credit facility, extension fee					0.075%
Remaining borrowing capacity					$ 724,000,000
Line of Credit | Revolving Credit Facility | Minimum
Debt Instrument [Line Items]
Commitment fee percentage					0.125%
Line of Credit | Revolving Credit Facility | Minimum | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate, spread					0.775%
Line of Credit | Revolving Credit Facility | Maximum
Debt Instrument [Line Items]
Commitment fee percentage					0.30%
Line of Credit | Revolving Credit Facility | Maximum | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable rate, spread					1.45%
Senior Notes
Debt Instrument [Line Items]
Redemption price					100.00%
Senior Notes | 2.25% Senior Notes
Debt Instrument [Line Items]
Loan amount				$ 400,000,000	$ 400,000,000
Initial offering price				99.42%
Proceeds from issuance of debt				$ 395,300,000
Basis point used in determining redemption price prior to maturity					0.35%
Senior Notes | 2.75%, $600,000 aggregate principal
Debt Instrument [Line Items]
Loan amount			$ 600,000,000		$ 600,000,000
Initial offering price			98.95%
Proceeds from issuance of debt			$ 589,800,000
Senior Notes | 2.75%, $600,000 aggregate principal | Adjusted Treasury
Debt Instrument [Line Items]
Basis point used in determining redemption price prior to maturity					0.25%
Senior Notes | 2.00%, $400,000 aggregate principal
Debt Instrument [Line Items]
Loan amount		$ 400,000,000			$ 400,000,000
Initial offering price		99.97%
Proceeds from issuance of debt		$ 397,400,000
Senior Notes | 2.00%, $400,000 aggregate principal | Adjusted Treasury
Debt Instrument [Line Items]
Basis point used in determining redemption price prior to maturity					0.20%
Senior Notes | 2.90%, $400,000 aggregate principal
Debt Instrument [Line Items]
Loan amount	$ 400,000,000				$ 400,000,000
Initial offering price	99.53%
Proceeds from issuance of debt	$ 395,400,000
Senior Notes | 2.90%, $400,000 aggregate principal | Adjusted Treasury
Debt Instrument [Line Items]
Basis point used in determining redemption price prior to maturity					0.25%
Senior Notes | 3.70% Senior Notes
Debt Instrument [Line Items]
Repurchased face amount				122,900,000						$ 177,100,000
Repurchase face amount plus prepayment premium				$ 126,000,000						$ 180,900,000
Loss on early extinguishment of debt						$ (7,300,000)
Senior Notes | 3.60% Senior Notes and 5.25% Senior Notes
Debt Instrument [Line Items]
Loss on early extinguishment of debt					$ (58,400,000)
Senior Notes | 3.60% Senior Notes
Debt Instrument [Line Items]
Loan amount					350,000,000
Repurchased face amount			184,400,000						$ 165,600,000
Repurchase face amount plus prepayment premium			196,700,000						176,300,000
Senior Notes | 5.250% Senior Notes
Debt Instrument [Line Items]
Loan amount					250,000,000
Repurchased face amount			145,600,000						104,400,000
Repurchase face amount plus prepayment premium			$ 164,700,000						$ 117,700,000
Senior Notes | 5.0% Senior Notes
Debt Instrument [Line Items]
Loan amount					300,000,000
Repurchased face amount								$ 300,000,000
Repurchase face amount plus prepayment premium								$ 336,400,000
Loss on early extinguishment of debt					$ (38,200,000)

Interest Rate Derivatives (Deta

Interest Rate Derivatives (Details) $ in Thousands	Sep. 22, 2020USD ($)	Dec. 31, 2021USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Aug. 31, 2020USD ($)derivative
Fair values of interest rate swap derivatives
Fair value of interest rate swaps		$ (3,289)		$ (3,289)
Reclassification adjustments on interest rate derivatives				0	$ (51,865)	$ 0
Derivatives in Hedging Relationships
Amount of Income (Loss) Recognized in AOCL on Derivatives				1,379	(39,454)	(24,321)
Amount of (Loss) Gain Reclassified from AOCL into Interest Expense on Statement of Operations				(5,048)	(3,725)	1,415
Gain (loss) on derivative instruments, net				0	(53,196)	0
Payments for hedge, investing activities				0	53,130	0
Interest rate swaps
Fair values of interest rate swap derivatives
Notional amount of forecasted transaction not probable of occurring							$ 225,000
Derivatives in Hedging Relationships
Number of interest rate derivatives discontinued due to forecasted transaction not probable of occurring | derivative							3
Payments for hedge, investing activities	$ 53,100
Interest rate swaps | Reclassification out of Accumulated Other Comprehensive Income | Accumulated Net Gain (Loss) from Cash Flow Hedges Including Portion Attributable to Noncontrolling Interest
Derivatives in Hedging Relationships
Gain (loss) on derivative instruments, net				0	(51,865)	0
Interest rate swaps | Interest Expense
Derivatives in Hedging Relationships
Amount of (Loss) Gain Reclassified from AOCL into Interest Expense on Statement of Operations				(5,048)	(3,725)	1,415
Interest rate swaps | Interest Rate Derivatives
Fair values of interest rate swap derivatives
Reclassification adjustments on interest rate derivatives			$ 51,900
Interest rate swaps | Prepaid expenses and other assets, net
Fair value of interest rate derivatives and balance sheet classification
Interest rate swaps designated as cash flow hedges		355		355	0
Interest rate swaps | Interest rate derivatives (liabilities)
Fair value of interest rate derivatives and balance sheet classification
Interest rate swaps designated as cash flow hedges		(2,960)		(2,960)	(9,522)
Interest rate swap not designated		(684)		(684)	0
Interest rate swap, effective September 1, 2016, swap three | Interest Expense
Fair values of interest rate swap derivatives
Reclassification adjustments on interest rate derivatives		(221)
Undesignated Swaps
Derivatives in Hedging Relationships
Gain (loss) on derivative instruments, net				0	(1,265)	$ 0
Designated
Fair values of interest rate swap derivatives
Fair value of interest rate swaps					(9,522)
Designated | Interest rate swaps
Derivatives in Hedging Relationships
Approximate amount to be reclassified from AOCL to interest expense over the next 12 months		3,400		3,400
Fair value of derivative liability		3,700		3,700
Settlement amount of derivative obligation at termination value		4,100		4,100
Designated | Interest rate swap, effective September 1, 2016, swap one
Fair values of interest rate swap derivatives
Notional Amount		$ 100,000		$ 100,000
Fixed Rate		1.901%		1.901%
Fair value of interest rate swaps		$ (1,361)		$ (1,361)	(3,394)
Designated | Interest rate swap, effective September 1, 2016, swap two
Fair values of interest rate swap derivatives
Notional Amount		$ 100,000		$ 100,000
Fixed Rate		1.905%		1.905%
Fair value of interest rate swaps		$ (1,365)		$ (1,365)	(3,401)
Designated | Interest rate swap, effective September 1, 2016, swap three
Fair values of interest rate swap derivatives
Fair value of interest rate swaps					(1,704)
Designated | Interest rate swap, effective August 1, 2019
Fair values of interest rate swap derivatives
Notional Amount		$ 11,120		$ 11,120
Fixed Rate		1.678%		1.678%
Fair value of interest rate swaps		$ (234)		$ (234)	(733)
Notional amount of interest rate derivatives after scheduled amortization		10,000		10,000
Designated | Interest rate swap, effective April 2020, swap two
Fair values of interest rate swap derivatives
Notional Amount		$ 23,000		$ 23,000
Fixed Rate		0.573%		0.573%
Fair value of interest rate swaps		$ 355		$ 355	$ (290)
Notional amount of interest rate derivatives after scheduled amortization		22,100		22,100
Not Designated as Hedging Instrument | Interest rate swap, effective September 1, 2016, swap three
Fair values of interest rate swap derivatives
Notional Amount		$ 50,000		$ 50,000
Fixed Rate		1.908%		1.908%
Fair value of interest rate swaps		$ (684)		$ (684)
Notional amount of forecasted transaction not probable of occurring		$ 50,000		$ 50,000

Redeemable Noncontrolling Int_3

Redeemable Noncontrolling Interests (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)joint_venture	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Noncontrolling Interest [Abstract]
Number of joint ventures with redeemable noncontrolling interests | joint_venture	2
Redeemable Noncontrolling Interest [Roll Forward]
Beginning balance	$ 25,430	$ 29,431	$ 26,260
Distributions to noncontrolling interests	(3,307)	(14,034)	(2,413)
Net income attributable to noncontrolling interests	3,160	3,426	3,835
Adjustment to arrive at fair value of interests	1,615	6,607	1,749
Ending balance	$ 26,898	$ 25,430	$ 29,431

Equity - COPT and Subsidiaries

Equity - COPT and Subsidiaries (Details) - USD ($)	1 Months Ended	12 Months Ended
	Nov. 30, 2018	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Common Shares
Number of common shares for each converted common unit (in shares)		1	1	1
Number of operating partnerships units converted into common shares (in units)		8,054	14,009	105,039
Dividends declared per common share (in dollars per share)		$ 1.10	$ 1.10	$ 1.10
Preferred Shares
Preferred Stock
Number of preferred shares authorized		25,000,000
Number of preferred shares of beneficial interest authorized (in dollars per share)		$ 0.01
2018 ATM Program | Common Shares
Common Shares
At-market-stock, offering program established, aggregate value	$ 300,000,000
Shares issued to the public (in shares)		0
Forward Equity Sale Agreement | Common Shares
Common Shares
Shares issued to the public (in shares)				1,600,000
Net proceeds from issuance of shares after underwriting discounts and commissions but before offering expenses				$ 46,500,000
Initial gross offering price per share (in dollars per share)				$ 31

Share-Based Compensation and _3

Share-Based Compensation and Other Compensation Matters (Narrative) (Details) $ / shares in Units, $ in Thousands	Feb. 01, 2022shares	Feb. 03, 2021shares	Jan. 13, 2020shares	Jan. 01, 2019$ / shares	Dec. 31, 2021USD ($)formPercentile_Rank$ / sharesshares	Dec. 31, 2020USD ($)$ / sharesshares	Dec. 31, 2019USD ($)$ / sharesshares	May 31, 2017shares
Executives and Non-Employee Trustees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated pre-vesting forfeitures					0.00%	0.00%	0.00%
Minimum | All Other Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated pre-vesting forfeitures					0.00%	0.00%	0.00%
Maximum | All Other Employees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated pre-vesting forfeitures					8.00%	8.00%	8.00%
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $					$ 5,200
Expected weighted average period during which unrecognized compensation cost will be recognized					2 years
Aggregate intrinsic value of shares issued | $					$ 4,300	$ 4,400	$ 4,900
Grant date fair value (in dollars per share or unit) | $ / shares					$ 26.17	$ 25.22	$ 26.56
Number of common shares issued (in shares)					164,575	173,191	185,001
Grant date fair value (in dollars per share or unit) of awards issued | $ / shares					$ 25.95	$ 28.14	$ 28.01
Restricted shares | Non-Employee Trustees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					1 year
Performance-based PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $					$ 3,000
Expected weighted average period during which unrecognized compensation cost will be recognized					2 years
Percentile ranks to fall between for PIUs | Percentile_Rank					2
Percent of award distribution rights					10.00%
Performance period of the award					3 years
Performance-based PIUs | Former Executive Vice President and Chief Operating Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares excluded from outstanding amount (shares)					73,184
Time-based PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $					$ 2,700
Expected weighted average period during which unrecognized compensation cost will be recognized					2 years
Aggregate intrinsic value of shares issued | $					$ 1,200	$ 640
Grant date fair value (in dollars per share or unit) | $ / shares					$ 26.16	$ 25.47	$ 26.01
Number of common shares issued (in shares)					45,244	25,182
Grant date fair value (in dollars per share or unit) of awards issued | $ / shares					$ 25.28	$ 26.30
Time-based PIUs | Non-Employee Trustees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					1 year
Deferred Share Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost | $					$ 34
Aggregate intrinsic value of shares issued | $							$ 86
Grant date fair value (in dollars per share or unit) | $ / shares					$ 27.12	$ 23.68	$ 27.60
Number of common shares issued (in shares)					0	0	3,097
Grant date fair value (in dollars per share or unit) of awards issued | $ / shares							$ 26.77
Deferred Share Awards | Non-Employee Trustees
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period					1 year
Profit Interest Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of forms of profit interest units | form					2
Performance share units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period of the award					3 years
The number of percentile ranks to fall between to earn interpolated PSUs between such percentile ranks, conditioned on the percentile rank exceeding 25% | Percentile_Rank					2
2017 Omnibus Equity and Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of common shares of beneficial interest authorized to be issued								3,400,000
2017 PSU Grants | Performance share units | Executives
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued for awards vested in period (in shares)			23,181
2018 PSU Grants | Performance share units | Executives
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued for awards vested in period (in shares)		93,824
2019 PB PIU | Performance-based PIUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Baseline Common Share Value (in dollars per share) | $ / shares				$ 21.03
Expected volatility of common shares (as a percent)				21.00%
Risk-free interest rate (as a percent)				2.51%
2019 PB PIU | Performance-based PIUs | Executives | Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued for awards vested in period (in shares)	156,104

Share-Based Compensation and _4

Share-Based Compensation and Other Compensation Matters (Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-Based Compensation
Share-based compensation cost	$ 8,698	$ 7,060	$ 7,456
General, administrative and leasing expenses
Share-Based Compensation
Share-based compensation cost	6,881	5,385	5,748
Property operating expenses
Share-Based Compensation
Share-based compensation cost	1,098	1,119	966
Capitalized to development activities
Share-Based Compensation
Share-based compensation cost	$ 719	$ 556	$ 742

Share-Based Compensation and _5

Share-Based Compensation and Other Compensation Matters (Restricted Shares and TB-PIUs Activity) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted shares
Shares
Unvested at the beginning of the period (in shares or units)	360,817	392,863	438,685
Stock awards granted (in shares or units)	177,995	166,918	195,520
Forfeited (in shares or units)	(39,664)	(25,773)	(56,341)
Vested (in shares or units)	(164,575)	(173,191)	(185,001)
Unvested at the end of the period (in shares or units)	334,573	360,817	392,863
Unvested shares as of December 31, 2020 that are expected to vest (in shares)	306,658
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share or unit)	$ 26.16	$ 27.49	$ 28.38
Grant date fair value (in dollars per share or unit)	26.17	25.22	26.56
Forfeited (in dollars per share or unit)	26.62	27.12	29.44
Vested (in dollars per share or unit)	25.95	28.14	28.01
Unvested at the end of the period (in dollars per share or unit)	26.22	$ 26.16	$ 27.49
Unvested shares as of December 31, 2021 that are expected to vest (in dollars per share or unit)	$ 26.22
Restricted shares | Former Executive Vice President and Chief Operating Officer
Shares
Forfeited (in shares or units)		(9,064)
Time-based PIUs
Shares
Unvested at the beginning of the period (in shares or units)	114,334	61,820	0
Stock awards granted (in shares or units)	93,983	98,318	61,820
Forfeited (in shares or units)		(20,622)
Vested (in shares or units)	(45,244)	(25,182)
Unvested at the end of the period (in shares or units)	163,073	114,334	61,820
Unvested shares as of December 31, 2020 that are expected to vest (in shares)	162,472
Weighted Average Grant Date Fair Value
Unvested at the beginning of the period (in dollars per share or unit)	$ 25.57	$ 26.01
Grant date fair value (in dollars per share or unit)	26.16	25.47	$ 26.01
Forfeited (in dollars per share or unit)		25.50
Vested (in dollars per share or unit)	25.28	26.30
Unvested at the end of the period (in dollars per share or unit)	25.99	$ 25.57	$ 26.01
Unvested shares as of December 31, 2021 that are expected to vest (in dollars per share or unit)	$ 25.99

Share-Based Compensation and _6

Share-Based Compensation and Other Compensation Matters (Grants to Executives) (Details) - USD ($) $ in Thousands	Jan. 01, 2021	Jan. 01, 2020	Jan. 01, 2019	Jan. 01, 2018	Jan. 01, 2017	Dec. 31, 2021
Performance-based PIUs | 2019 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)			193,682
Grant Date Fair Value			$ 2,415
Unvested at the end of the period (in shares or units)						156,104
Performance-based PIUs | 2020 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)		176,758
Grant Date Fair Value		$ 2,891
Unvested at the end of the period (in shares or units)						141,152
Performance-based PIUs | 2021 PB PIU
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)	227,544
Grant Date Fair Value	$ 3,417
Unvested at the end of the period (in shares or units)						227,544
Performance share units | 2017 PSU Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)					39,351
Grant Date Fair Value					$ 1,415
Performance share units | 2018 PSU Grants
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards granted (in shares or units)				59,110
Grant Date Fair Value				$ 1,890

Share-Based Compensation and _7

Share-Based Compensation and Other Compensation Matters (Percentile Grant and Assumptions) (Details) - $ / shares	Jan. 01, 2021	Jan. 01, 2020	Jan. 01, 2019	Dec. 31, 2021
Performance-based PIUs
Potential earned payout for defined levels of performance under awards
Earned payout (as a percent of PSUs/ PIUs granted) on 75th or greater percentile rank				100.00%
Earned payout (as a percent of PSUs/ PIUs granted) on 50th percentile rank (target)				50.00%
Earned payout (as a percent of PSUs/ PIUs granted) on 25th percentile rank				25.00%
Performance share units/ PB PIUs granted on percentile rank below 25th (as a percent)				0.00%
Performance-based PIUs | 2019 PB PIU
Assumptions used to value stock awards
Baseline Common Share Value (in dollars per share)			$ 21.03
Expected Volatility of Common Shares			21.00%
Risk-free Interest Rate			2.51%
Performance-based PIUs | 2019 PB PIU | Target Level
Assumptions used to value stock awards
Grant date fair value (in dollars per share or unit)			$ 24.94
Performance-based PIUs | 2020 PB PIU
Assumptions used to value stock awards
Baseline Common Share Value (in dollars per share)		$ 29.38
Expected Volatility of Common Shares		18.00%
Risk-free Interest Rate		1.65%
Performance-based PIUs | 2020 PB PIU | Target Level
Assumptions used to value stock awards
Grant date fair value (in dollars per share or unit)		$ 32.71
Performance-based PIUs | 2021 PB PIU
Assumptions used to value stock awards
Baseline Common Share Value (in dollars per share)	$ 26.08
Expected Volatility of Common Shares	34.70%
Risk-free Interest Rate	0.18%
Performance-based PIUs | 2021 PB PIU | Target Level
Assumptions used to value stock awards
Grant date fair value (in dollars per share or unit)	$ 30.03
Performance share units
Potential earned payout for defined levels of performance under awards
Earned payout (as a percent of PSUs/ PIUs granted) on 75th or greater percentile rank				200.00%
Earned payout (as a percent of PSUs/ PIUs granted) on 50th percentile rank (target)				100.00%
Earned payout (as a percent of PSUs/ PIUs granted) on 25th percentile rank				50.00%
Performance share units/ PB PIUs granted on percentile rank below 25th (as a percent)				0.00%

Share-Based Compensation and _8

Share-Based Compensation and Other Compensation Matters (Deferred Share Awards) (Details) - Deferred Share Awards - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Deferred Share Awards Granted (in shares)	3,416	10,679	3,432
Aggregate Grant Date Fair Value	$ 93	$ 253	$ 95
Grant Date Fair Value Per Share (in dollars per share or unit)	$ 27.12	$ 23.68	$ 27.60
Number of common shares issued (in shares)	0	0	3,097
Grant date fair value (in dollars per share or unit) of awards issued			$ 26.77
Aggregate intrinsic value of shares issued			$ 86

Credit Losses, Financial Asse_3

Credit Losses, Financial Assets and Other Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Off-Balance Sheet Credit Exposures [Roll Forward]
Beginning balance	$ 0	$ 0
Cumulative effect of change for adoption of credit loss guidance		1,340
Credit loss (recoveries) expense	0	(1,340)
Other changes		0
Ending balance	0	0	$ 0
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Beginning balance	4,697	97
Cumulative effect of change for adoption of credit loss guidance		5,541
Credit loss (recoveries) expense	(1,128)	(933)	0
Other changes		(8)
Ending balance	3,569	4,697	97
Other Assets
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	643	0
Cumulative effect of change for adoption of credit loss guidance		144
Credit loss (recoveries) expense	270	559
Other changes		(60)
Ending balance	913	643	0
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	913	643	0
Other Assets | Accounts Receivable, Net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	257
Ending balance	218	257
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	218	257
Other Assets | Prepaid expenses and other assets, net
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	386
Ending balance	695	386
Credit Losses, Financial Assets and Other Instruments [Roll Forward]
Accounts receivable, allowance for credit loss	695	386
Investing Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,851	0
Cumulative effect of change for adoption of credit loss guidance		3,732
Credit loss (recoveries) expense	(1,252)	(881)
Other changes		0
Ending balance	1,599	2,851	0
Tenant Notes Receivables
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	1,203	97
Cumulative effect of change for adoption of credit loss guidance		325
Credit loss (recoveries) expense	(146)	729
Other changes		52
Ending balance	$ 1,057	$ 1,203	$ 97

Credit Losses, Financial Asse_4

Credit Losses, Financial Assets and Other Instruments (Credit Risk Classification) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Investing Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	$ 70,434
2017	1,069
2018	0
2019	6,041
2020	1,675
2021	4,606
Total	83,825	$ 71,605
Investing Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	70,434
2017	1,069
2018	0
2019	0
2020	1,675
2021	4,606
Total	77,784
Investing Receivables | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	0
2017	0
2018	0
2019	6,041
2020	0
2021	0
Total	6,041
Tenant Notes Receivables
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	207
2017	0
2018	1,053
2019	200
2020	1,995
2021	0
Total	3,455
Tenant Notes Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	0
2017	0
2018	921
2019	63
2020	271
2021	0
Total	1,255
Tenant Notes Receivables | Non-investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	207
2017	0
2018	132
2019	137
2020	1,724
2021	0
Total	2,200
Sales-Type Lease Receivables | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
2016 and Earlier	0
2017	0
2018	0
2019	0
2020	6,194
2021	0
Total	$ 6,194

Information by Business Segme_3

Information by Business Segment (Segment Financial Information for Our Reportable Segments) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment financial information for real estate operations
Revenues from real estate operations	$ 185,932	$ 166,919	$ 157,207	$ 154,388	$ 156,607	$ 148,801	$ 138,321	$ 138,625	$ 664,446	$ 582,354	$ 611,821
Property operating expenses									(213,377)	(190,796)	(185,449)
UJV NOI allocable to COPT									4,029	6,951	5,705
Segment assets	4,262,452				4,077,023				4,262,452	4,077,023
Segment assets
Segment financial information for real estate operations
Segment assets	3,575,462				3,388,978				3,575,462	3,388,978
Real estate operations
Segment financial information for real estate operations
Revenues from real estate operations									587,060	538,725	527,463
Property operating expenses									(230,219)	(203,840)	(198,143)
UJV NOI allocable to COPT									4,029	6,951	5,705
NOI from real estate operations									360,870	341,836	335,025
Additions to long-lived assets									96,785	81,479	76,350
Transfers from non-operating properties									284,949	476,362	226,001
Real estate operations | Total Defense/IT Locations
Segment financial information for real estate operations
Revenues from real estate operations									483,332	447,519	435,486
Property operating expenses									(175,595)	(159,377)	(153,803)
UJV NOI allocable to COPT									4,029	6,951	5,705
NOI from real estate operations									311,766	295,093	287,388
Additions to long-lived assets									59,205	52,924	54,404
Transfers from non-operating properties									245,630	393,271	227,013
Real estate operations | Total Defense/IT Locations | Fort Meade/BW Corridor
Segment financial information for real estate operations
Revenues from real estate operations									262,120	254,197	252,781
Property operating expenses									(92,521)	(85,032)	(82,815)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									169,599	169,165	169,966
Additions to long-lived assets									45,647	31,295	34,618
Transfers from non-operating properties									70,514	21,859	18,606
Real estate operations | Total Defense/IT Locations | Northern Virginia Defense/IT
Segment financial information for real estate operations
Revenues from real estate operations									62,390	57,817	55,742
Property operating expenses									(23,218)	(21,321)	(19,779)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									39,172	36,496	35,963
Additions to long-lived assets									5,823	11,620	9,326
Transfers from non-operating properties									90,050	2,557	4,548
Real estate operations | Total Defense/IT Locations | Lackland Air Force Base
Segment financial information for real estate operations
Revenues from real estate operations									57,756	50,982	51,140
Property operating expenses									(30,535)	(29,055)	(29,042)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									27,221	21,927	22,098
Additions to long-lived assets									0	0	0
Transfers from non-operating properties									59,323	456	10,781
Real estate operations | Total Defense/IT Locations | Navy Support Locations
Segment financial information for real estate operations
Revenues from real estate operations									33,757	32,869	32,659
Property operating expenses									(13,617)	(12,655)	(13,579)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									20,140	20,214	19,080
Additions to long-lived assets									4,193	7,104	8,912
Transfers from non-operating properties									0	0	0
Real estate operations | Total Defense/IT Locations | Redstone Arsenal
Segment financial information for real estate operations
Revenues from real estate operations									35,727	22,515	16,593
Property operating expenses									(11,618)	(8,119)	(6,626)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									24,109	14,396	9,967
Additions to long-lived assets									3,542	2,905	1,548
Transfers from non-operating properties									22,739	138,122	33,606
Real estate operations | Total Defense/IT Locations | Data Center Shells
Segment financial information for real estate operations
Revenues from real estate operations									31,582	29,139	26,571
Property operating expenses									(4,086)	(3,195)	(1,962)
UJV NOI allocable to COPT									4,029	6,951	5,705
NOI from real estate operations									31,525	32,895	30,314
Additions to long-lived assets									0	0	0
Transfers from non-operating properties									3,004	230,277	159,472
Real estate operations | Regional Office
Segment financial information for real estate operations
Revenues from real estate operations									66,570	60,627	59,611
Property operating expenses									(32,623)	(29,144)	(29,682)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									33,947	31,483	29,929
Additions to long-lived assets									35,412	17,232	20,925
Transfers from non-operating properties									39,319	83,091	0
Real estate operations | Wholesale Data Center
Segment financial information for real estate operations
Revenues from real estate operations									30,490	27,011	29,405
Property operating expenses									(17,424)	(13,543)	(13,213)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									13,066	13,468	16,192
Additions to long-lived assets									1,680	10,856	893
Transfers from non-operating properties									0	0	(1,012)
Real estate operations | Other
Segment financial information for real estate operations
Revenues from real estate operations									6,668	3,568	2,961
Property operating expenses									(4,577)	(1,776)	(1,445)
UJV NOI allocable to COPT									0	0	0
NOI from real estate operations									2,091	1,792	1,516
Additions to long-lived assets									488	467	128
Transfers from non-operating properties									0	0	0
Real estate operations | Segment assets
Segment financial information for real estate operations
Segment assets	3,575,462				3,388,978				3,575,462	3,388,978	3,024,958
Real estate operations | Segment assets | Total Defense/IT Locations
Segment financial information for real estate operations
Segment assets	2,823,694				2,692,912				2,823,694	2,692,912	2,426,019
Real estate operations | Segment assets | Total Defense/IT Locations | Fort Meade/BW Corridor
Segment financial information for real estate operations
Segment assets	1,332,399				1,277,849				1,332,399	1,277,849	1,280,656
Real estate operations | Segment assets | Total Defense/IT Locations | Northern Virginia Defense/IT
Segment financial information for real estate operations
Segment assets	471,760				392,714				471,760	392,714	396,914
Real estate operations | Segment assets | Total Defense/IT Locations | Lackland Air Force Base
Segment financial information for real estate operations
Segment assets	198,200				142,137				198,200	142,137	146,592
Real estate operations | Segment assets | Total Defense/IT Locations | Navy Support Locations
Segment financial information for real estate operations
Segment assets	170,985				178,897				170,985	178,897	184,257
Real estate operations | Segment assets | Total Defense/IT Locations | Redstone Arsenal
Segment financial information for real estate operations
Segment assets	300,252				281,386				300,252	281,386	138,501
Real estate operations | Segment assets | Total Defense/IT Locations | Data Center Shells
Segment financial information for real estate operations
Segment assets	350,098				419,929				350,098	419,929	279,099
Real estate operations | Segment assets | Regional Office
Segment financial information for real estate operations
Segment assets	555,090				490,422				555,090	490,422	392,319
Real estate operations | Segment assets | Wholesale Data Center
Segment financial information for real estate operations
Segment assets	192,647				201,820				192,647	201,820	202,935
Real estate operations | Segment assets | Other
Segment financial information for real estate operations
Segment assets	$ 4,031				$ 3,824				$ 4,031	$ 3,824	$ 3,685

Information by Business Segme_4

Information by Business Segment (Reconciliation of Revenue) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation of segment revenues to total revenues
Construction contract and other service revenues									$ 107,876	$ 70,640	$ 113,763
Less: Revenues from discontinued operations (Note 4)									(30,490)	(27,011)	(29,405)
Total revenues	$ 185,932	$ 166,919	$ 157,207	$ 154,388	$ 156,607	$ 148,801	$ 138,321	$ 138,625	664,446	582,354	611,821
Operating Expenses [Abstract]
Property operating expenses									213,377	190,796	185,449
Less: Property operating expenses from discontinued operations (Note 4)									(16,842)	(13,044)	(12,694)
Reconciliation of UJV NOI allocable to COPT to Equity Income in Unconsolidated entities [Abstract]
UJV NOI allocable to COPT									4,029	6,951	5,705
Less: Income from UJVs allocable to COPT attributable to depreciation and amortization expense and interest expense									(2,930)	(5,120)	(4,065)
Add: Equity in loss of unconsolidated non-real estate entities									(6)	(6)	(7)
Equity in income of unconsolidated entities									1,093	1,825	1,633
Computation of net operating income from service operations
Construction contract and other service revenues									107,876	70,640	113,763
Construction contract and other service expenses									(104,053)	(67,615)	(109,962)
Real estate operations
Reconciliation of segment revenues to total revenues
Total revenues									587,060	538,725	527,463
Operating Expenses [Abstract]
Property operating expenses									230,219	203,840	198,143
Less: Property operating expenses from discontinued operations (Note 4)									(16,842)	(13,044)	(12,694)
Reconciliation of UJV NOI allocable to COPT to Equity Income in Unconsolidated entities [Abstract]
UJV NOI allocable to COPT									4,029	6,951	5,705
Service operations
Computation of net operating income from service operations
NOI from service operations									$ 3,823	$ 3,025	$ 3,801

Information by Business Segme_5

Information by Business Segment (NOI Reconciliation) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment financial information for real estate operations
Interest and other income									$ 7,879	$ 8,574	$ 7,894
Credit loss recoveries									1,128	933	0
Gain on sales of real estate									65,590	30,209	105,230
Gain on sale of investment in unconsolidated real estate joint venture									0	29,416	0
Equity in income of unconsolidated entities									1,093	1,825	1,633
Income tax (expense) benefit									(145)	(353)	217
Depreciation and other amortization associated with real estate operations									(137,543)	(126,503)	(125,008)
Impairment losses									0	(1,530)	(329)
General, administrative and leasing expenses									(36,127)	(33,001)	(35,402)
Business development expenses and land carry costs									(4,647)	(4,473)	(4,239)
Interest expense									(65,398)	(67,937)	(71,052)
UJV NOI allocable to COPT included in equity in income of unconsolidated entities									(4,029)	(6,951)	(5,705)
Revenues from real estate operations from discontinued operations (Note 4)									(30,490)	(27,011)	(29,405)
Property operating expenses from discontinued operations (Note 4)									16,842	13,044	12,694
Loss on early extinguishment of debt									(100,626)	(7,306)	0
Loss on interest rate derivatives									0	(53,196)	0
Income from continuing operations	$ 13,552	$ 28,343	$ 43,219	$ (6,894)	$ 82,182	$ (30,991)	$ 24,984	$ 24,426	78,220	100,601	195,354
Real estate operations
Segment financial information for real estate operations
NOI from real estate operations									360,870	341,836	335,025
UJV NOI allocable to COPT included in equity in income of unconsolidated entities									(4,029)	(6,951)	(5,705)
Property operating expenses from discontinued operations (Note 4)									16,842	13,044	12,694
Service operations
Segment financial information for real estate operations
NOI from service operations									$ 3,823	$ 3,025	$ 3,801

Information by Business Segme_6

Information by Business Segment (Assets Reconciliation) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of segment assets to total assets
Total consolidated assets	$ 4,262,452	$ 4,077,023
Operating properties lease liabilities included in segment assets	29,342	30,746
Segment assets
Reconciliation of segment assets to total assets
Total consolidated assets	3,575,462	3,388,978
Operating properties lease liabilities included in segment assets	29,342	30,721
Non-operating property assets
Reconciliation of segment assets to total assets
Total consolidated assets	449,144	466,991
Other assets
Reconciliation of segment assets to total assets
Total consolidated assets	$ 208,504	$ 190,333

Construction Contract and Oth_3

Construction Contract and Other Service Revenues (Construction Contract and Other Service Revenues by Compensation Arrangement) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 107,876	$ 70,640	$ 113,763
Construction
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	104,020	66,087	112,170
Design
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	2,250	2,343	612
Other
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	1,606	2,210	981
GMP
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	68,113	22,032	67,708
Cost-plus fee
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	24,260	34,025	34,386
FFP
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	13,897	12,373	10,688
Other
Disaggregation of Revenue [Line Items]
Construction contract and other service revenues	$ 1,606	$ 2,210	$ 981

Construction Contract and Oth_4

Construction Contract and Other Service Revenues (Percentage of Revenue - Narrative) (Details)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Construction contract revenue | Revenue from Contract with Customer Benchmark | Concentration risk | United States Government
Concentration Risk [Line Items]
Percentage of revenue	79.00%	55.00%	74.00%

Construction Contract and Oth_5

Construction Contract and Other Service Revenues (Rollforwards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Change in Accounts Receivable
Beginning balance	$ 41,637
Ending balance	40,752	$ 41,637
Change in Contract with Customer, Asset
Beginning balance	10,343
Ending balance	22,384	10,343
Construction contract revenue
Change in Accounts Receivable
Beginning balance	13,997	12,378
Ending balance	7,193	13,997
Change in Contract with Customer, Asset
Beginning balance	10,343	17,223
Ending balance	22,384	10,343
Change in Contract with Customer, Liability
Beginning balance	4,610	1,184
Ending balance	2,499	4,610
Portion of beginning balance recognized in revenue during the year	$ 2,664	$ 757

Construction Contract and Oth_6

Construction Contract and Other Service Revenues (Remaining Performance Obligations) (Details) $ in Millions	Dec. 31, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Remaining performance obligations	$ 147.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue from Contract with Customer [Abstract]
Remaining performance obligations	$ 98
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Expected timing	1 year

Construction Contract and Oth_7

Construction Contract and Other Service Revenues (Deferred Incremental Costs Incurred) (Details) - Construction contract revenue - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Deferred incremental costs	$ 0	$ 0
Credit loss expense	$ 211,000	$ 528,000

Earnings Per Share ("EPS") (Bas

Earnings Per Share ("EPS") (Basic and Diluted Calculation) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Numerator:
Income from continuing operations										$ 78,220		$ 100,601		$ 195,354
Income from continuing operations attributable to noncontrolling interests										(4,994)		(5,477)		(8,255)
Income from continuing operations attributable to share-based compensation awards for basic EPS										(467)		(433)		(638)
Numerator for basic EPS from continuing operations attributable to COPT common shareholders										72,759		94,691		186,461
Redeemable noncontrolling interests										(128)		0		132
Adjustment to income from continuing operations attributable to share-based compensation awards for diluted EPS										44		27		33
Numerator for diluted EPS from continuing operations attributable to COPT common shareholders										72,675		94,718		186,626
Discontinued operations		$ 1,413	$ 451	$ 679	$ 815	$ 1,367	$ (351)	$ 137	$ 1,124	3,358		2,277		4,650
Discontinued operations attributable to noncontrolling interests										(43)		(27)		(57)
Income from discontinued operations attributable to share-based compensation awards for diluted EPS										6		2		(18)
Numerator for diluted EPS from continuing operations attributable to COPT common shareholders										$ 75,996		$ 96,970		$ 191,201
Denominator (all weighted averages):
Denominator for basic EPS (common shares)										111,960		111,788		111,196
Dilutive effect of redeemable noncontrolling interests (common shares)										128		0		119
Dilutive effect of share-based compensation awards (common shares)										330		288		308
Denominator for diluted EPS (common shares)										112,418		112,076		111,623
Basic Earnings per common share:
Income from continuing operations attributable to COPT common shareholders (in dollars per share)	[1]									$ 0.65		$ 0.85		$ 1.68
Discontinued operations attributable to COPT common shareholders (in dollars per share)	[1]									0.03		0.02		0.04
Net income attributable to COPT common shareholders - basic (in dollars per share)		$ 0.12	$ 0.24	$ 0.38	$ (0.06)	$ 0.73	$ (0.29)	$ 0.21	$ 0.21	0.68	[1]	0.87	[1]	1.72	[1]
Diluted Earnings per common share:
Income from continuing operations attributable to COPT common shareholders (in dollars per share)	[1]									0.65		0.85		1.67
Discontinued operations attributable to COPT common shareholders (in dollars per share)										0.03		0.02		0.04
Net income attributable to COPT common shareholders - diluted (in dollars per share)		$ 0.12	$ 0.24	$ 0.38	$ (0.06)	$ 0.73	$ (0.29)	$ 0.21	$ 0.21	$ 0.68	[1]	$ 0.87	[1]	$ 1.71	[1]
[1]	Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.

Earnings Per Share ("EPS") (Ant

Earnings Per Share ("EPS") (Anti-Dilutive Securities) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Conversion of common units
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	1,257	1,236	1,299
Conversion of redeemable noncontrolling interests
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	804	957	896
Conversion of Series I preferred units
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	0	171	176
Weighted average restricted shares and deferred share awards
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	412	430	441
Weighted average TB-PIUs
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)	158	89	51
Weighted average options
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)			12
Weighted average shares related to forward equity sale agreements
Antidilutive securities
Weighted average antidilutive securities excluded from computation of diluted earnings per share (in shares)			376

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Dec. 31, 2021USD ($)property
Commitments and Contingencies
Estimate of possible loss	$ 3.6
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	$ 31

Quarterly Data (Unaudited) (Det

Quarterly Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021		Dec. 31, 2020		Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$ 185,932	$ 166,919	$ 157,207	$ 154,388	$ 156,607	$ 148,801	$ 138,321	$ 138,625	$ 664,446		$ 582,354		$ 611,821
(Loss) income from continuing operations	13,552	28,343	43,219	(6,894)	82,182	(30,991)	24,984	24,426	78,220		100,601		195,354
Discontinued operations	1,413	451	679	815	1,367	(351)	137	1,124	3,358		2,277		4,650
Net income	14,965	28,794	43,898	(6,079)	83,549	(31,342)	25,121	25,550	$ 81,578		$ 102,878		$ 200,004
Net income attributable to noncontrolling interests in consolidated entities	(1,257)	(1,693)	(1,497)	(590)	(1,881)	(503)	(1,624)	(1,496)
Net income attributable to COPT common shareholders	$ 13,708	$ 27,101	$ 42,401	$ (6,669)	$ 81,668	$ (31,845)	$ 23,497	$ 24,054
Basic EPS (in dollars per share)	$ 0.12	$ 0.24	$ 0.38	$ (0.06)	$ 0.73	$ (0.29)	$ 0.21	$ 0.21	$ 0.68	[1]	$ 0.87	[1]	$ 1.72	[1]
Diluted EPS (in dollars per share)	$ 0.12	$ 0.24	$ 0.38	$ (0.06)	$ 0.73	$ (0.29)	$ 0.21	$ 0.21	$ 0.68	[1]	$ 0.87	[1]	$ 1.71	[1]
[1]	Basic and diluted earnings per common share are calculated based on amounts attributable to common shareholders of Corporate Office Properties Trust.

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - 9651 Hornbaker Road - Disposed of by sale $ in Millions	Jan. 25, 2022USD ($)
Subsequent Event [Line Items]
Transaction value	$ 222.5
Discontinued operation, gain on disposal	$ 29

Schedule III - Real Estate an_2

Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Real Estate and Accumulated Depreciation
Encumbrances	$ 121,425
Initial Cost
Land	720,485
Building and Land Improvements	3,635,390
Costs Capitalized Subsequent to Acquisition	603,834
Gross Amounts Carried At Close of Period
Land	720,485
Building and Land Improvements	4,239,224
Total	4,959,709	$ 4,686,802	$ 4,348,006	$ 4,148,529
Accumulated Depreciation	(1,234,908)	(1,124,253)	$ (1,007,120)	$ (897,903)
Additional information
Debt, net	2,272,304	2,086,918
Net discounts and deferred financing costs	26,000
Aggregate cost of assets for federal income tax purposes	$ 3,700,000
Buildings improvements | Minimum
Additional information
Estimated lives over which depreciation is recognized	10 years
Buildings improvements | Maximum
Additional information
Estimated lives over which depreciation is recognized	40 years
Revolving Credit Facility
Additional information
Debt, net	$ 76,000	143,000
Term Loan Facility
Additional information
Debt, net	299,420	$ 398,447
Unsecured Senior Notes
Additional information
Debt, net	1,800,000
Unsecured notes payable
Additional information
Debt, net	753
Fixed rate mortgage loans
Additional information
Net discounts and deferred financing costs	798
100 Light Street
Initial Cost
Land	26,715
Building and Land Improvements	58,002
Costs Capitalized Subsequent to Acquisition	36,662
Gross Amounts Carried At Close of Period
Land	26,715
Building and Land Improvements	94,664
Total	121,379
Accumulated Depreciation	(25,616)
100 Secured Gateway
Initial Cost
Building and Land Improvements	71,089
Gross Amounts Carried At Close of Period
Building and Land Improvements	71,089
Total	71,089
Accumulated Depreciation	(2,340)
1000 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	9,281
Initial Cost
Building and Land Improvements	20,533
Costs Capitalized Subsequent to Acquisition	76
Gross Amounts Carried At Close of Period
Building and Land Improvements	20,609
Total	20,609
Accumulated Depreciation	(4,525)
1100 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	9,913
Initial Cost
Building and Land Improvements	19,593
Costs Capitalized Subsequent to Acquisition	88
Gross Amounts Carried At Close of Period
Building and Land Improvements	19,681
Total	19,681
Accumulated Depreciation	(3,912)
114 National Business Parkway
Initial Cost
Land	364
Building and Land Improvements	3,109
Costs Capitalized Subsequent to Acquisition	404
Gross Amounts Carried At Close of Period
Land	364
Building and Land Improvements	3,513
Total	3,877
Accumulated Depreciation	(1,679)
1200 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	11,441
Initial Cost
Building and Land Improvements	22,389
Costs Capitalized Subsequent to Acquisition	141
Gross Amounts Carried At Close of Period
Building and Land Improvements	22,530
Total	22,530
Accumulated Depreciation	(4,509)
1201 M Street SE
Initial Cost
Building and Land Improvements	49,775
Costs Capitalized Subsequent to Acquisition	10,290
Gross Amounts Carried At Close of Period
Building and Land Improvements	60,065
Total	60,065
Accumulated Depreciation	(21,051)
1201 Winterson Road
Initial Cost
Land	2,130
Building and Land Improvements	17,009
Costs Capitalized Subsequent to Acquisition	901
Gross Amounts Carried At Close of Period
Land	2,130
Building and Land Improvements	17,910
Total	20,040
Accumulated Depreciation	(5,952)
1220 12th Street, SE
Initial Cost
Building and Land Improvements	42,464
Costs Capitalized Subsequent to Acquisition	9,749
Gross Amounts Carried At Close of Period
Building and Land Improvements	52,213
Total	52,213
Accumulated Depreciation	(19,797)
1243 Winterson Road
Initial Cost
Land	630
Gross Amounts Carried At Close of Period
Land	630
Total	630
131 National Business Parkway
Initial Cost
Land	1,906
Building and Land Improvements	7,623
Costs Capitalized Subsequent to Acquisition	5,893
Gross Amounts Carried At Close of Period
Land	1,906
Building and Land Improvements	13,516
Total	15,422
Accumulated Depreciation	(7,872)
132 National Business Parkway
Initial Cost
Land	2,917
Building and Land Improvements	12,259
Costs Capitalized Subsequent to Acquisition	4,876
Gross Amounts Carried At Close of Period
Land	2,917
Building and Land Improvements	17,135
Total	20,052
Accumulated Depreciation	(11,075)
133 National Business Parkway
Initial Cost
Land	2,517
Building and Land Improvements	10,068
Costs Capitalized Subsequent to Acquisition	6,731
Gross Amounts Carried At Close of Period
Land	2,517
Building and Land Improvements	16,799
Total	19,316
Accumulated Depreciation	(10,935)
134 National Business Parkway
Initial Cost
Land	3,684
Building and Land Improvements	7,517
Costs Capitalized Subsequent to Acquisition	5,726
Gross Amounts Carried At Close of Period
Land	3,684
Building and Land Improvements	13,243
Total	16,927
Accumulated Depreciation	(8,014)
1340 Ashton Road
Initial Cost
Land	905
Building and Land Improvements	3,620
Costs Capitalized Subsequent to Acquisition	2,540
Gross Amounts Carried At Close of Period
Land	905
Building and Land Improvements	6,160
Total	7,065
Accumulated Depreciation	(3,423)
13450 Sunrise Valley Drive
Initial Cost
Land	1,386
Building and Land Improvements	5,576
Costs Capitalized Subsequent to Acquisition	4,952
Gross Amounts Carried At Close of Period
Land	1,386
Building and Land Improvements	10,528
Total	11,914
Accumulated Depreciation	(6,583)
13454 Sunrise Valley Drive
Initial Cost
Land	2,847
Building and Land Improvements	11,986
Costs Capitalized Subsequent to Acquisition	9,240
Gross Amounts Carried At Close of Period
Land	2,847
Building and Land Improvements	21,226
Total	24,073
Accumulated Depreciation	(12,918)
135 National Business Parkway
Initial Cost
Land	2,484
Building and Land Improvements	9,750
Costs Capitalized Subsequent to Acquisition	7,003
Gross Amounts Carried At Close of Period
Land	2,484
Building and Land Improvements	16,753
Total	19,237
Accumulated Depreciation	(10,779)
1362 Mellon Road
Initial Cost
Land	950
Building and Land Improvements	3,864
Costs Capitalized Subsequent to Acquisition	1,632
Gross Amounts Carried At Close of Period
Land	950
Building and Land Improvements	5,496
Total	6,446
Accumulated Depreciation	(1,193)
13857 McLearen Road
Initial Cost
Land	3,507
Building and Land Improvements	30,177
Costs Capitalized Subsequent to Acquisition	4,915
Gross Amounts Carried At Close of Period
Land	3,507
Building and Land Improvements	35,092
Total	38,599
Accumulated Depreciation	(13,842)
140 National Business Parkway
Initial Cost
Land	3,407
Building and Land Improvements	24,167
Costs Capitalized Subsequent to Acquisition	1,784
Gross Amounts Carried At Close of Period
Land	3,407
Building and Land Improvements	25,951
Total	29,358
Accumulated Depreciation	(11,646)
141 National Business Parkway
Initial Cost
Land	2,398
Building and Land Improvements	9,538
Costs Capitalized Subsequent to Acquisition	4,832
Gross Amounts Carried At Close of Period
Land	2,398
Building and Land Improvements	14,370
Total	16,768
Accumulated Depreciation	(9,758)
14280 Park Meadow Drive
Initial Cost
Land	3,731
Building and Land Improvements	15,953
Costs Capitalized Subsequent to Acquisition	5,500
Gross Amounts Carried At Close of Period
Land	3,731
Building and Land Improvements	21,453
Total	25,184
Accumulated Depreciation	(10,469)
1460 Dorsey Road
Initial Cost
Land	1,577
Building and Land Improvements	115
Gross Amounts Carried At Close of Period
Land	1,577
Building and Land Improvements	115
Total	1,692
14840 Conference Center Drive
Initial Cost
Land	1,572
Building and Land Improvements	8,175
Costs Capitalized Subsequent to Acquisition	5,730
Gross Amounts Carried At Close of Period
Land	1,572
Building and Land Improvements	13,905
Total	15,477
Accumulated Depreciation	(7,895)
14850 Conference Center Drive
Initial Cost
Land	1,615
Building and Land Improvements	8,358
Costs Capitalized Subsequent to Acquisition	5,345
Gross Amounts Carried At Close of Period
Land	1,615
Building and Land Improvements	13,703
Total	15,318
Accumulated Depreciation	(7,455)
14900 Conference Center Drive
Initial Cost
Land	3,436
Building and Land Improvements	14,402
Costs Capitalized Subsequent to Acquisition	9,282
Gross Amounts Carried At Close of Period
Land	3,436
Building and Land Improvements	23,684
Total	27,120
Accumulated Depreciation	(14,024)
1501 South Clinton Street
Initial Cost
Land	27,964
Building and Land Improvements	51,990
Costs Capitalized Subsequent to Acquisition	23,731
Gross Amounts Carried At Close of Period
Land	27,964
Building and Land Improvements	75,721
Total	103,685
Accumulated Depreciation	(31,475)
15049 Conference Center Drive
Initial Cost
Land	4,415
Building and Land Improvements	20,365
Costs Capitalized Subsequent to Acquisition	17,846
Gross Amounts Carried At Close of Period
Land	4,415
Building and Land Improvements	38,211
Total	42,626
Accumulated Depreciation	(20,360)
15059 Conference Center Drive
Initial Cost
Land	5,753
Building and Land Improvements	13,615
Costs Capitalized Subsequent to Acquisition	4,543
Gross Amounts Carried At Close of Period
Land	5,753
Building and Land Improvements	18,158
Total	23,911
Accumulated Depreciation	(10,774)
1550 West Nursery Road
Initial Cost
Land	14,071
Building and Land Improvements	16,930
Gross Amounts Carried At Close of Period
Land	14,071
Building and Land Improvements	16,930
Total	31,001
Accumulated Depreciation	(6,678)
1560 West Nursery Road
Initial Cost
Land	1,441
Building and Land Improvements	113
Gross Amounts Carried At Close of Period
Land	1,441
Building and Land Improvements	113
Total	1,554
Accumulated Depreciation	(22)
1610 West Nursery Road
Initial Cost
Land	259
Building and Land Improvements	246
Gross Amounts Carried At Close of Period
Land	259
Building and Land Improvements	246
Total	505
Accumulated Depreciation	(29)
1616 West Nursery Road
Initial Cost
Land	393
Building and Land Improvements	3,323
Costs Capitalized Subsequent to Acquisition	75
Gross Amounts Carried At Close of Period
Land	393
Building and Land Improvements	3,398
Total	3,791
Accumulated Depreciation	(358)
1622 West Nursery Road
Initial Cost
Land	393
Building and Land Improvements	2,542
Gross Amounts Carried At Close of Period
Land	393
Building and Land Improvements	2,542
Total	2,935
Accumulated Depreciation	(308)
16442 Commerce Drive
Initial Cost
Land	613
Building and Land Improvements	2,582
Costs Capitalized Subsequent to Acquisition	1,135
Gross Amounts Carried At Close of Period
Land	613
Building and Land Improvements	3,717
Total	4,330
Accumulated Depreciation	(1,988)
16480 Commerce Drive
Initial Cost
Land	1,856
Building and Land Improvements	7,425
Costs Capitalized Subsequent to Acquisition	2,619
Gross Amounts Carried At Close of Period
Land	1,856
Building and Land Improvements	10,044
Total	11,900
Accumulated Depreciation	(4,754)
16501 Commerce Drive
Initial Cost
Land	522
Building and Land Improvements	2,090
Costs Capitalized Subsequent to Acquisition	1,040
Gross Amounts Carried At Close of Period
Land	522
Building and Land Improvements	3,130
Total	3,652
Accumulated Depreciation	(1,544)
16539 Commerce Drive
Initial Cost
Land	688
Building and Land Improvements	2,860
Costs Capitalized Subsequent to Acquisition	2,326
Gross Amounts Carried At Close of Period
Land	688
Building and Land Improvements	5,186
Total	5,874
Accumulated Depreciation	(3,058)
16541 Commerce Drive
Initial Cost
Land	773
Building and Land Improvements	3,094
Costs Capitalized Subsequent to Acquisition	2,596
Gross Amounts Carried At Close of Period
Land	773
Building and Land Improvements	5,690
Total	6,463
Accumulated Depreciation	(2,989)
16543 Commerce Drive
Initial Cost
Land	436
Building and Land Improvements	1,742
Costs Capitalized Subsequent to Acquisition	838
Gross Amounts Carried At Close of Period
Land	436
Building and Land Improvements	2,580
Total	3,016
Accumulated Depreciation	(1,348)
1751 Pinnacle Drive
Initial Cost
Land	10,486
Building and Land Improvements	42,339
Costs Capitalized Subsequent to Acquisition	33,825
Gross Amounts Carried At Close of Period
Land	10,486
Building and Land Improvements	76,164
Total	86,650
Accumulated Depreciation	(42,720)
1753 Pinnacle Drive
Initial Cost
Land	8,275
Building and Land Improvements	34,353
Costs Capitalized Subsequent to Acquisition	24,092
Gross Amounts Carried At Close of Period
Land	8,275
Building and Land Improvements	58,445
Total	66,720
Accumulated Depreciation	(28,325)
206 Research Boulevard
Gross Amounts Carried At Close of Period
Total	0
209 Research Boulevard
Initial Cost
Land	134
Building and Land Improvements	1,711
Costs Capitalized Subsequent to Acquisition	543
Gross Amounts Carried At Close of Period
Land	134
Building and Land Improvements	2,254
Total	2,388
Accumulated Depreciation	(687)
210 Research Boulevard
Initial Cost
Land	113
Building and Land Improvements	1,402
Costs Capitalized Subsequent to Acquisition	426
Gross Amounts Carried At Close of Period
Land	113
Building and Land Improvements	1,828
Total	1,941
Accumulated Depreciation	(543)
2100 L Street
Initial Cost
Land	57,385
Building and Land Improvements	94,152
Gross Amounts Carried At Close of Period
Land	57,385
Building and Land Improvements	94,152
Total	151,537
Accumulated Depreciation	(1,987)
2100 Rideout Road
Initial Cost
Building and Land Improvements	7,336
Costs Capitalized Subsequent to Acquisition	2,995
Gross Amounts Carried At Close of Period
Building and Land Improvements	10,331
Total	10,331
Accumulated Depreciation	(2,274)
22289 Exploration Drive
Initial Cost
Land	1,422
Building and Land Improvements	5,719
Costs Capitalized Subsequent to Acquisition	2,129
Gross Amounts Carried At Close of Period
Land	1,422
Building and Land Improvements	7,848
Total	9,270
Accumulated Depreciation	(4,369)
22299 Exploration Drive
Initial Cost
Land	1,362
Building and Land Improvements	5,791
Costs Capitalized Subsequent to Acquisition	3,049
Gross Amounts Carried At Close of Period
Land	1,362
Building and Land Improvements	8,840
Total	10,202
Accumulated Depreciation	(5,297)
22300 Exploration Drive
Initial Cost
Land	1,094
Building and Land Improvements	5,038
Costs Capitalized Subsequent to Acquisition	2,770
Gross Amounts Carried At Close of Period
Land	1,094
Building and Land Improvements	7,808
Total	8,902
Accumulated Depreciation	(4,134)
22309 Exploration Drive
Initial Cost
Land	2,243
Building and Land Improvements	10,419
Costs Capitalized Subsequent to Acquisition	8,114
Gross Amounts Carried At Close of Period
Land	2,243
Building and Land Improvements	18,533
Total	20,776
Accumulated Depreciation	(8,947)
23535 Cottonwood Parkway
Initial Cost
Land	692
Building and Land Improvements	3,051
Costs Capitalized Subsequent to Acquisition	648
Gross Amounts Carried At Close of Period
Land	692
Building and Land Improvements	3,699
Total	4,391
Accumulated Depreciation	(2,193)
250 W Pratt St
Initial Cost
Land	8,057
Building and Land Improvements	34,588
Costs Capitalized Subsequent to Acquisition	18,482
Gross Amounts Carried At Close of Period
Land	8,057
Building and Land Improvements	53,070
Total	61,127
Accumulated Depreciation	(18,418)
2600 Park Tower Drive
Initial Cost
Land	20,284
Building and Land Improvements	34,443
Costs Capitalized Subsequent to Acquisition	4,621
Gross Amounts Carried At Close of Period
Land	20,284
Building and Land Improvements	39,064
Total	59,348
Accumulated Depreciation	(8,392)
2691 Technology Drive
Initial Cost
Land	2,098
Building and Land Improvements	17,334
Costs Capitalized Subsequent to Acquisition	5,565
Gross Amounts Carried At Close of Period
Land	2,098
Building and Land Improvements	22,899
Total	24,997
Accumulated Depreciation	(12,224)
2701 Technology Drive
Initial Cost
Land	1,737
Building and Land Improvements	15,266
Costs Capitalized Subsequent to Acquisition	7,033
Gross Amounts Carried At Close of Period
Land	1,737
Building and Land Improvements	22,299
Total	24,036
Accumulated Depreciation	(13,380)
2711 Technology Drive
Initial Cost
Land	2,251
Building and Land Improvements	21,611
Costs Capitalized Subsequent to Acquisition	4,335
Gross Amounts Carried At Close of Period
Land	2,251
Building and Land Improvements	25,946
Total	28,197
Accumulated Depreciation	(14,988)
2720 Technology Drive
Initial Cost
Land	3,863
Building and Land Improvements	29,272
Costs Capitalized Subsequent to Acquisition	2,897
Gross Amounts Carried At Close of Period
Land	3,863
Building and Land Improvements	32,169
Total	36,032
Accumulated Depreciation	(14,204)
2721 Technology Drive
Initial Cost
Land	4,611
Building and Land Improvements	14,597
Costs Capitalized Subsequent to Acquisition	3,783
Gross Amounts Carried At Close of Period
Land	4,611
Building and Land Improvements	18,380
Total	22,991
Accumulated Depreciation	(10,792)
2730 Hercules Road
Initial Cost
Land	8,737
Building and Land Improvements	31,612
Costs Capitalized Subsequent to Acquisition	8,998
Gross Amounts Carried At Close of Period
Land	8,737
Building and Land Improvements	40,610
Total	49,347
Accumulated Depreciation	(23,935)
30 Light Street
Initial Cost
Building and Land Improvements	12,101
Costs Capitalized Subsequent to Acquisition	1,008
Gross Amounts Carried At Close of Period
Building and Land Improvements	13,109
Total	13,109
Accumulated Depreciation	(2,308)
300 Secured Gateway
Initial Cost
Building and Land Improvements	3,128
Gross Amounts Carried At Close of Period
Building and Land Improvements	3,128
Total	3,128
300 Sentinel Drive
Initial Cost
Land	1,517
Building and Land Improvements	59,165
Costs Capitalized Subsequent to Acquisition	2,569
Gross Amounts Carried At Close of Period
Land	1,517
Building and Land Improvements	61,734
Total	63,251
Accumulated Depreciation	(18,370)
302 Sentinel Drive
Initial Cost
Land	2,648
Building and Land Improvements	29,687
Costs Capitalized Subsequent to Acquisition	2,293
Gross Amounts Carried At Close of Period
Land	2,648
Building and Land Improvements	31,980
Total	34,628
Accumulated Depreciation	(10,987)
304 Sentinel Drive
Initial Cost
Land	3,411
Building and Land Improvements	24,917
Costs Capitalized Subsequent to Acquisition	4,875
Gross Amounts Carried At Close of Period
Land	3,411
Building and Land Improvements	29,792
Total	33,203
Accumulated Depreciation	(12,067)
306 Sentinel Drive
Initial Cost
Land	3,260
Building and Land Improvements	22,592
Costs Capitalized Subsequent to Acquisition	3,303
Gross Amounts Carried At Close of Period
Land	3,260
Building and Land Improvements	25,895
Total	29,155
Accumulated Depreciation	(10,098)
308 Sentinel Drive
Initial Cost
Land	1,422
Building and Land Improvements	26,208
Costs Capitalized Subsequent to Acquisition	2,354
Gross Amounts Carried At Close of Period
Land	1,422
Building and Land Improvements	28,562
Total	29,984
Accumulated Depreciation	(7,882)
310 Sentinel Way
Initial Cost
Land	2,372
Building and Land Improvements	42,591
Gross Amounts Carried At Close of Period
Land	2,372
Building and Land Improvements	42,591
Total	44,963
Accumulated Depreciation	(6,103)
310 The Bridge Street
Initial Cost
Land	261
Building and Land Improvements	26,530
Costs Capitalized Subsequent to Acquisition	5,227
Gross Amounts Carried At Close of Period
Land	261
Building and Land Improvements	31,757
Total	32,018
Accumulated Depreciation	(12,236)
312 Sentinel Way
Initial Cost
Land	3,138
Building and Land Improvements	27,797
Gross Amounts Carried At Close of Period
Land	3,138
Building and Land Improvements	27,797
Total	30,935
Accumulated Depreciation	(5,084)
314 Sentinel Way
Initial Cost
Land	1,254
Building and Land Improvements	7,741
Gross Amounts Carried At Close of Period
Land	1,254
Building and Land Improvements	7,741
Total	8,995
Accumulated Depreciation	(1,480)
316 Sentinel Way
Initial Cost
Land	2,748
Building and Land Improvements	38,156
Costs Capitalized Subsequent to Acquisition	193
Gross Amounts Carried At Close of Period
Land	2,748
Building and Land Improvements	38,349
Total	41,097
Accumulated Depreciation	(9,410)
318 Sentinel Way
Initial Cost
Land	2,185
Building and Land Improvements	28,426
Costs Capitalized Subsequent to Acquisition	560
Gross Amounts Carried At Close of Period
Land	2,185
Building and Land Improvements	28,986
Total	31,171
Accumulated Depreciation	(11,482)
320 Sentinel Way
Initial Cost
Land	2,067
Building and Land Improvements	21,623
Costs Capitalized Subsequent to Acquisition	127
Gross Amounts Carried At Close of Period
Land	2,067
Building and Land Improvements	21,750
Total	23,817
Accumulated Depreciation	(7,606)
322 Sentinel Way
Initial Cost
Land	2,605
Building and Land Improvements	22,827
Costs Capitalized Subsequent to Acquisition	1,910
Gross Amounts Carried At Close of Period
Land	2,605
Building and Land Improvements	24,737
Total	27,342
Accumulated Depreciation	(9,329)
324 Sentinel Way
Initial Cost
Land	1,656
Building and Land Improvements	23,018
Costs Capitalized Subsequent to Acquisition	6
Gross Amounts Carried At Close of Period
Land	1,656
Building and Land Improvements	23,024
Total	24,680
Accumulated Depreciation	(6,531)
4000 Market Street
Real Estate and Accumulated Depreciation
Encumbrances	6,052
Initial Cost
Building and Land Improvements	9,187
Gross Amounts Carried At Close of Period
Building and Land Improvements	9,187
Total	9,187
Accumulated Depreciation	(626)
410 National Business Parkway
Initial Cost
Land	1,831
Building and Land Improvements	23,257
Costs Capitalized Subsequent to Acquisition	2,259
Gross Amounts Carried At Close of Period
Land	1,831
Building and Land Improvements	25,516
Total	27,347
Accumulated Depreciation	(6,032)
4100 Market Street
Real Estate and Accumulated Depreciation
Encumbrances	5,269
Initial Cost
Building and Land Improvements	8,020
Costs Capitalized Subsequent to Acquisition	7
Gross Amounts Carried At Close of Period
Building and Land Improvements	8,027
Total	8,027
Accumulated Depreciation	(506)
420 National Business Parkway
Initial Cost
Land	2,370
Building and Land Improvements	29,534
Costs Capitalized Subsequent to Acquisition	148
Gross Amounts Carried At Close of Period
Land	2,370
Building and Land Improvements	29,682
Total	32,052
Accumulated Depreciation	(5,467)
430 National Business Parkway
Initial Cost
Land	1,852
Building and Land Improvements	21,563
Costs Capitalized Subsequent to Acquisition	1,893
Gross Amounts Carried At Close of Period
Land	1,852
Building and Land Improvements	23,456
Total	25,308
Accumulated Depreciation	(5,746)
44408 Pecan Court
Initial Cost
Land	817
Building and Land Improvements	1,583
Costs Capitalized Subsequent to Acquisition	1,751
Gross Amounts Carried At Close of Period
Land	817
Building and Land Improvements	3,334
Total	4,151
Accumulated Depreciation	(1,983)
44414 Pecan Court
Initial Cost
Land	405
Building and Land Improvements	1,619
Costs Capitalized Subsequent to Acquisition	1,138
Gross Amounts Carried At Close of Period
Land	405
Building and Land Improvements	2,757
Total	3,162
Accumulated Depreciation	(1,686)
44417 Pecan Court
Initial Cost
Land	434
Building and Land Improvements	3,822
Costs Capitalized Subsequent to Acquisition	180
Gross Amounts Carried At Close of Period
Land	434
Building and Land Improvements	4,002
Total	4,436
Accumulated Depreciation	(2,195)
44420 Pecan Court
Initial Cost
Land	344
Building and Land Improvements	890
Costs Capitalized Subsequent to Acquisition	291
Gross Amounts Carried At Close of Period
Land	344
Building and Land Improvements	1,181
Total	1,525
Accumulated Depreciation	(607)
44425 Pecan Court
Initial Cost
Land	1,309
Building and Land Improvements	3,506
Costs Capitalized Subsequent to Acquisition	2,394
Gross Amounts Carried At Close of Period
Land	1,309
Building and Land Improvements	5,900
Total	7,209
Accumulated Depreciation	(3,757)
45310 Abell House Lane
Initial Cost
Land	2,272
Building and Land Improvements	13,808
Costs Capitalized Subsequent to Acquisition	878
Gross Amounts Carried At Close of Period
Land	2,272
Building and Land Improvements	14,686
Total	16,958
Accumulated Depreciation	(3,888)
4600 River Road
Initial Cost
Building and Land Improvements	24,032
Gross Amounts Carried At Close of Period
Building and Land Improvements	24,032
Total	24,032
Accumulated Depreciation	(436)
46579 Expedition Drive
Initial Cost
Land	1,406
Building and Land Improvements	5,796
Costs Capitalized Subsequent to Acquisition	2,874
Gross Amounts Carried At Close of Period
Land	1,406
Building and Land Improvements	8,670
Total	10,076
Accumulated Depreciation	(4,563)
46591 Expedition Drive
Initial Cost
Land	1,200
Building and Land Improvements	7,199
Costs Capitalized Subsequent to Acquisition	3,408
Gross Amounts Carried At Close of Period
Land	1,200
Building and Land Improvements	10,607
Total	11,807
Accumulated Depreciation	(4,557)
4851 Stonecroft Boulevard
Initial Cost
Land	1,878
Building and Land Improvements	11,558
Costs Capitalized Subsequent to Acquisition	194
Gross Amounts Carried At Close of Period
Land	1,878
Building and Land Improvements	11,752
Total	13,630
Accumulated Depreciation	(5,001)
540 National Business Parkway
Initial Cost
Land	2,035
Building and Land Improvements	31,249
Costs Capitalized Subsequent to Acquisition	41
Gross Amounts Carried At Close of Period
Land	2,035
Building and Land Improvements	31,290
Total	33,325
Accumulated Depreciation	(3,321)
5520 Research Park Drive
Initial Cost
Building and Land Improvements	20,072
Costs Capitalized Subsequent to Acquisition	1,757
Gross Amounts Carried At Close of Period
Building and Land Improvements	21,829
Total	21,829
Accumulated Depreciation	(7,078)
5522 Research Park Drive
Initial Cost
Building and Land Improvements	4,550
Costs Capitalized Subsequent to Acquisition	855
Gross Amounts Carried At Close of Period
Building and Land Improvements	5,405
Total	5,405
Accumulated Depreciation	(1,851)
560 National Business Parkway
Initial Cost
Land	2,193
Building and Land Improvements	28,973
Gross Amounts Carried At Close of Period
Land	2,193
Building and Land Improvements	28,973
Total	31,166
5801 University Research Court
Real Estate and Accumulated Depreciation
Encumbrances	11,120
Initial Cost
Building and Land Improvements	17,431
Costs Capitalized Subsequent to Acquisition	144
Gross Amounts Carried At Close of Period
Building and Land Improvements	17,575
Total	17,575
Accumulated Depreciation	(1,772)
5825 University Research Court
Real Estate and Accumulated Depreciation
Encumbrances	19,552
Initial Cost
Building and Land Improvements	22,771
Costs Capitalized Subsequent to Acquisition	1,678
Gross Amounts Carried At Close of Period
Building and Land Improvements	24,449
Total	24,449
Accumulated Depreciation	(8,014)
5850 University Research Court
Real Estate and Accumulated Depreciation
Encumbrances	20,686
Initial Cost
Building and Land Improvements	31,906
Costs Capitalized Subsequent to Acquisition	894
Gross Amounts Carried At Close of Period
Building and Land Improvements	32,800
Total	32,800
Accumulated Depreciation	(9,746)
6000 Redstone Gateway
Initial Cost
Building and Land Improvements	8,550
Gross Amounts Carried At Close of Period
Building and Land Improvements	8,550
Total	8,550
Accumulated Depreciation	(201)
610 Guardian Way
Initial Cost
Land	7,636
Building and Land Improvements	49,873
Gross Amounts Carried At Close of Period
Land	7,636
Building and Land Improvements	49,873
Total	57,509
Accumulated Depreciation	(276)
6200 Redstone Gateway
Initial Cost
Building and Land Improvements	14,067
Gross Amounts Carried At Close of Period
Building and Land Improvements	14,067
Total	14,067
6700 Alexander Bell Drive
Initial Cost
Land	1,755
Building and Land Improvements	7,019
Costs Capitalized Subsequent to Acquisition	9,541
Gross Amounts Carried At Close of Period
Land	1,755
Building and Land Improvements	16,560
Total	18,315
Accumulated Depreciation	(9,466)
6708 Alexander Bell Drive
Initial Cost
Land	897
Building and Land Improvements	12,693
Costs Capitalized Subsequent to Acquisition	1,618
Gross Amounts Carried At Close of Period
Land	897
Building and Land Improvements	14,311
Total	15,208
Accumulated Depreciation	(4,956)
6711 Columbia Gateway Drive
Initial Cost
Land	2,683
Building and Land Improvements	23,239
Costs Capitalized Subsequent to Acquisition	2,258
Gross Amounts Carried At Close of Period
Land	2,683
Building and Land Improvements	25,497
Total	28,180
Accumulated Depreciation	(9,995)
6716 Alexander Bell Drive
Initial Cost
Land	1,242
Building and Land Improvements	4,969
Costs Capitalized Subsequent to Acquisition	4,672
Gross Amounts Carried At Close of Period
Land	1,242
Building and Land Improvements	9,641
Total	10,883
Accumulated Depreciation	(6,399)
6721 Columbia Gateway Drive
Initial Cost
Land	1,753
Building and Land Improvements	34,090
Costs Capitalized Subsequent to Acquisition	7,318
Gross Amounts Carried At Close of Period
Land	1,753
Building and Land Improvements	41,408
Total	43,161
Accumulated Depreciation	(11,406)
6724 Alexander Bell Drive
Initial Cost
Land	449
Building and Land Improvements	5,039
Costs Capitalized Subsequent to Acquisition	2,492
Gross Amounts Carried At Close of Period
Land	449
Building and Land Improvements	7,531
Total	7,980
Accumulated Depreciation	(4,042)
6731 Columbia Gateway Drive
Initial Cost
Land	2,807
Building and Land Improvements	19,098
Costs Capitalized Subsequent to Acquisition	5,689
Gross Amounts Carried At Close of Period
Land	2,807
Building and Land Improvements	24,787
Total	27,594
Accumulated Depreciation	(14,085)
6740 Alexander Bell Drive
Initial Cost
Land	1,424
Building and Land Improvements	4,209
Costs Capitalized Subsequent to Acquisition	757
Gross Amounts Carried At Close of Period
Land	1,424
Building and Land Improvements	4,966
Total	6,390
Accumulated Depreciation	(2,627)
6741 Columbia Gateway Drive
Initial Cost
Land	675
Building and Land Improvements	1,711
Costs Capitalized Subsequent to Acquisition	176
Gross Amounts Carried At Close of Period
Land	675
Building and Land Improvements	1,887
Total	2,562
Accumulated Depreciation	(715)
6750 Alexander Bell Drive
Initial Cost
Land	1,263
Building and Land Improvements	12,461
Costs Capitalized Subsequent to Acquisition	5,856
Gross Amounts Carried At Close of Period
Land	1,263
Building and Land Improvements	18,317
Total	19,580
Accumulated Depreciation	(11,133)
6760 Alexander Bell Drive
Initial Cost
Land	890
Building and Land Improvements	3,561
Costs Capitalized Subsequent to Acquisition	3,915
Gross Amounts Carried At Close of Period
Land	890
Building and Land Improvements	7,476
Total	8,366
Accumulated Depreciation	(5,115)
6940 Columbia Gateway Drive
Initial Cost
Land	3,545
Building and Land Improvements	9,916
Costs Capitalized Subsequent to Acquisition	9,227
Gross Amounts Carried At Close of Period
Land	3,545
Building and Land Improvements	19,143
Total	22,688
Accumulated Depreciation	(11,631)
6950 Columbia Gateway Drive
Initial Cost
Land	3,596
Building and Land Improvements	28,312
Costs Capitalized Subsequent to Acquisition	3,223
Gross Amounts Carried At Close of Period
Land	3,596
Building and Land Improvements	31,535
Total	35,131
Accumulated Depreciation	(12,711)
7000 Columbia Gateway Drive
Initial Cost
Land	3,131
Building and Land Improvements	12,103
Costs Capitalized Subsequent to Acquisition	8,551
Gross Amounts Carried At Close of Period
Land	3,131
Building and Land Improvements	20,654
Total	23,785
Accumulated Depreciation	(10,921)
7000 Redstone Gateway
Initial Cost
Building and Land Improvements	897
Gross Amounts Carried At Close of Period
Building and Land Improvements	897
Total	897
7005 Columbia Gateway Drive
Initial Cost
Land	3,036
Building and Land Improvements	747
Gross Amounts Carried At Close of Period
Land	3,036
Building and Land Improvements	747
Total	3,783
7015 Albert Einstein Drive
Initial Cost
Land	2,058
Building and Land Improvements	6,093
Costs Capitalized Subsequent to Acquisition	3,560
Gross Amounts Carried At Close of Period
Land	2,058
Building and Land Improvements	9,653
Total	11,711
Accumulated Depreciation	(5,005)
7061 Columbia Gateway Drive
Initial Cost
Land	729
Building and Land Improvements	3,094
Costs Capitalized Subsequent to Acquisition	2,884
Gross Amounts Carried At Close of Period
Land	729
Building and Land Improvements	5,978
Total	6,707
Accumulated Depreciation	(3,608)
7063 Columbia Gateway Drive
Initial Cost
Land	902
Building and Land Improvements	3,684
Costs Capitalized Subsequent to Acquisition	3,470
Gross Amounts Carried At Close of Period
Land	902
Building and Land Improvements	7,154
Total	8,056
Accumulated Depreciation	(4,721)
7065 Columbia Gateway Drive
Initial Cost
Land	919
Building and Land Improvements	3,763
Costs Capitalized Subsequent to Acquisition	3,145
Gross Amounts Carried At Close of Period
Land	919
Building and Land Improvements	6,908
Total	7,827
Accumulated Depreciation	(4,703)
7067 Columbia Gateway Drive
Initial Cost
Land	1,829
Building and Land Improvements	11,823
Costs Capitalized Subsequent to Acquisition	6,683
Gross Amounts Carried At Close of Period
Land	1,829
Building and Land Improvements	18,506
Total	20,335
Accumulated Depreciation	(9,409)
7100 Redstone Gateway
Initial Cost
Building and Land Improvements	12,975
Gross Amounts Carried At Close of Period
Building and Land Improvements	12,975
Total	12,975
Accumulated Depreciation	(204)
7125 Columbia Gateway Drive
Initial Cost
Land	20,487
Building and Land Improvements	49,844
Costs Capitalized Subsequent to Acquisition	24,637
Gross Amounts Carried At Close of Period
Land	20,487
Building and Land Improvements	74,481
Total	94,968
Accumulated Depreciation	(30,038)
7130 Columbia Gateway Drive
Initial Cost
Land	1,350
Building and Land Improvements	4,359
Costs Capitalized Subsequent to Acquisition	3,029
Gross Amounts Carried At Close of Period
Land	1,350
Building and Land Improvements	7,388
Total	8,738
Accumulated Depreciation	(4,101)
7134 Columbia Gateway Drive
Initial Cost
Land	704
Building and Land Improvements	4,700
Costs Capitalized Subsequent to Acquisition	729
Gross Amounts Carried At Close of Period
Land	704
Building and Land Improvements	5,429
Total	6,133
Accumulated Depreciation	(1,988)
7138 Columbia Gateway Drive
Initial Cost
Land	1,104
Building and Land Improvements	3,518
Costs Capitalized Subsequent to Acquisition	2,963
Gross Amounts Carried At Close of Period
Land	1,104
Building and Land Improvements	6,481
Total	7,585
Accumulated Depreciation	(4,286)
7142 Columbia Gateway Drive
Initial Cost
Land	1,342
Building and Land Improvements	7,148
Costs Capitalized Subsequent to Acquisition	2,771
Gross Amounts Carried At Close of Period
Land	1,342
Building and Land Improvements	9,919
Total	11,261
Accumulated Depreciation	(4,494)
7150 Columbia Gateway Drive
Initial Cost
Land	1,032
Building and Land Improvements	3,429
Costs Capitalized Subsequent to Acquisition	1,705
Gross Amounts Carried At Close of Period
Land	1,032
Building and Land Improvements	5,134
Total	6,166
Accumulated Depreciation	(1,938)
7150 Riverwood Drive
Initial Cost
Land	1,821
Building and Land Improvements	4,388
Costs Capitalized Subsequent to Acquisition	1,953
Gross Amounts Carried At Close of Period
Land	1,821
Building and Land Improvements	6,341
Total	8,162
Accumulated Depreciation	(3,162)
7160 Riverwood Drive
Initial Cost
Land	2,732
Building and Land Improvements	7,006
Costs Capitalized Subsequent to Acquisition	4,609
Gross Amounts Carried At Close of Period
Land	2,732
Building and Land Improvements	11,615
Total	14,347
Accumulated Depreciation	(5,300)
7170 Riverwood Drive
Initial Cost
Land	1,283
Building and Land Improvements	3,096
Costs Capitalized Subsequent to Acquisition	2,387
Gross Amounts Carried At Close of Period
Land	1,283
Building and Land Improvements	5,483
Total	6,766
Accumulated Depreciation	(2,787)
7175 Riverwood Drive
Initial Cost
Land	1,788
Building and Land Improvements	7,269
Gross Amounts Carried At Close of Period
Land	1,788
Building and Land Improvements	7,269
Total	9,057
Accumulated Depreciation	(1,479)
7200 Redstone Gateway
Initial Cost
Building and Land Improvements	8,348
Costs Capitalized Subsequent to Acquisition	81
Gross Amounts Carried At Close of Period
Building and Land Improvements	8,429
Total	8,429
Accumulated Depreciation	(1,611)
7200 Riverwood Drive
Initial Cost
Land	4,089
Building and Land Improvements	22,630
Costs Capitalized Subsequent to Acquisition	4,693
Gross Amounts Carried At Close of Period
Land	4,089
Building and Land Improvements	27,323
Total	31,412
Accumulated Depreciation	(13,365)
7205 Riverwood Drive
Initial Cost
Land	1,367
Building and Land Improvements	21,419
Gross Amounts Carried At Close of Period
Land	1,367
Building and Land Improvements	21,419
Total	22,786
Accumulated Depreciation	(4,523)
7272 Park Circle Drive
Initial Cost
Land	1,479
Building and Land Improvements	6,300
Costs Capitalized Subsequent to Acquisition	4,609
Gross Amounts Carried At Close of Period
Land	1,479
Building and Land Improvements	10,909
Total	12,388
Accumulated Depreciation	(5,971)
7318 Parkway Drive
Initial Cost
Land	972
Building and Land Improvements	3,888
Costs Capitalized Subsequent to Acquisition	1,647
Gross Amounts Carried At Close of Period
Land	972
Building and Land Improvements	5,535
Total	6,507
Accumulated Depreciation	(3,120)
7400 Redstone Gateway
Initial Cost
Building and Land Improvements	9,223
Costs Capitalized Subsequent to Acquisition	75
Gross Amounts Carried At Close of Period
Building and Land Improvements	9,298
Total	9,298
Accumulated Depreciation	(1,519)
7467 Ridge Road
Initial Cost
Land	1,565
Building and Land Improvements	3,116
Costs Capitalized Subsequent to Acquisition	5,997
Gross Amounts Carried At Close of Period
Land	1,565
Building and Land Improvements	9,113
Total	10,678
Accumulated Depreciation	(4,585)
7500 Advanced Gateway
Initial Cost
Building and Land Improvements	18,663
Gross Amounts Carried At Close of Period
Building and Land Improvements	18,663
Total	18,663
Accumulated Depreciation	(734)
7600 Advanced Gateway
Initial Cost
Building and Land Improvements	13,752
Gross Amounts Carried At Close of Period
Building and Land Improvements	13,752
Total	13,752
Accumulated Depreciation	(482)
7740 Milestone Parkway
Real Estate and Accumulated Depreciation
Encumbrances	16,432
Initial Cost
Land	3,825
Building and Land Improvements	34,176
Costs Capitalized Subsequent to Acquisition	1,254
Gross Amounts Carried At Close of Period
Land	3,825
Building and Land Improvements	35,430
Total	39,255
Accumulated Depreciation	(10,226)
7770 Backlick Road
Initial Cost
Land	6,387
Building and Land Improvements	78,891
Costs Capitalized Subsequent to Acquisition	1,528
Gross Amounts Carried At Close of Period
Land	6,387
Building and Land Improvements	80,419
Total	86,806
Accumulated Depreciation	(17,275)
7880 Milestone Parkway
Initial Cost
Land	4,857
Building and Land Improvements	26,836
Costs Capitalized Subsequent to Acquisition	1,338
Gross Amounts Carried At Close of Period
Land	4,857
Building and Land Improvements	28,174
Total	33,031
Accumulated Depreciation	(4,132)
8000 Rideout Road
Initial Cost
Building and Land Improvements	21,667
Gross Amounts Carried At Close of Period
Building and Land Improvements	21,667
Total	21,667
Accumulated Depreciation	(53)
8200 Rideout Road
Initial Cost
Building and Land Improvements	16,890
Gross Amounts Carried At Close of Period
Building and Land Improvements	16,890
Total	16,890
8300 Rideout Road
Initial Cost
Building and Land Improvements	18,301
Gross Amounts Carried At Close of Period
Building and Land Improvements	18,301
Total	18,301
8600 Advanced Gateway
Initial Cost
Building and Land Improvements	27,298
Gross Amounts Carried At Close of Period
Building and Land Improvements	27,298
Total	27,298
Accumulated Depreciation	(711)
8621 Robert Fulton Drive
Initial Cost
Land	2,317
Building and Land Improvements	12,642
Costs Capitalized Subsequent to Acquisition	6,191
Gross Amounts Carried At Close of Period
Land	2,317
Building and Land Improvements	18,833
Total	21,150
Accumulated Depreciation	(8,822)
8661 Robert Fulton Drive
Initial Cost
Land	1,510
Building and Land Improvements	3,764
Costs Capitalized Subsequent to Acquisition	3,302
Gross Amounts Carried At Close of Period
Land	1,510
Building and Land Improvements	7,066
Total	8,576
Accumulated Depreciation	(3,825)
8671 Robert Fulton Drive
Initial Cost
Land	1,718
Building and Land Improvements	4,280
Costs Capitalized Subsequent to Acquisition	4,294
Gross Amounts Carried At Close of Period
Land	1,718
Building and Land Improvements	8,574
Total	10,292
Accumulated Depreciation	(5,066)
870 Elkridge Landing Road
Initial Cost
Land	2,003
Building and Land Improvements	9,442
Costs Capitalized Subsequent to Acquisition	10,464
Gross Amounts Carried At Close of Period
Land	2,003
Building and Land Improvements	19,906
Total	21,909
Accumulated Depreciation	(12,706)
8800 Redstone Gateway
Real Estate and Accumulated Depreciation
Encumbrances	11,679
Initial Cost
Building and Land Improvements	18,465
Gross Amounts Carried At Close of Period
Building and Land Improvements	18,465
Total	18,465
Accumulated Depreciation	(974)
891 Elkridge Landing Road
Initial Cost
Land	1,165
Building and Land Improvements	4,772
Costs Capitalized Subsequent to Acquisition	3,844
Gross Amounts Carried At Close of Period
Land	1,165
Building and Land Improvements	8,616
Total	9,781
Accumulated Depreciation	(5,472)
901 Elkridge Landing Road
Initial Cost
Land	1,156
Building and Land Improvements	4,437
Costs Capitalized Subsequent to Acquisition	6,034
Gross Amounts Carried At Close of Period
Land	1,156
Building and Land Improvements	10,471
Total	11,627
Accumulated Depreciation	(5,115)
911 Elkridge Landing Road
Initial Cost
Land	1,215
Building and Land Improvements	4,861
Costs Capitalized Subsequent to Acquisition	3,307
Gross Amounts Carried At Close of Period
Land	1,215
Building and Land Improvements	8,168
Total	9,383
Accumulated Depreciation	(5,116)
938 Elkridge Landing Road
Initial Cost
Land	922
Building and Land Improvements	4,748
Costs Capitalized Subsequent to Acquisition	1,534
Gross Amounts Carried At Close of Period
Land	922
Building and Land Improvements	6,282
Total	7,204
Accumulated Depreciation	(3,420)
939 Elkridge Landing Road
Initial Cost
Land	939
Building and Land Improvements	3,756
Costs Capitalized Subsequent to Acquisition	4,470
Gross Amounts Carried At Close of Period
Land	939
Building and Land Improvements	8,226
Total	9,165
Accumulated Depreciation	(6,064)
9651 Hornbaker Road
Initial Cost
Land	6,050
Building and Land Improvements	250,407
Costs Capitalized Subsequent to Acquisition	17,785
Gross Amounts Carried At Close of Period
Land	6,050
Building and Land Improvements	268,192
Total	274,242
Accumulated Depreciation	(82,385)
Arundel Preserve
Initial Cost
Land	13,352
Building and Land Improvements	9,717
Gross Amounts Carried At Close of Period
Land	13,352
Building and Land Improvements	9,717
Total	23,069
Canton Crossing Land
Initial Cost
Land	17,285
Building and Land Improvements	8,409
Costs Capitalized Subsequent to Acquisition	227
Gross Amounts Carried At Close of Period
Land	17,285
Building and Land Improvements	8,636
Total	25,921
Canton Crossing Util Distr Ctr
Initial Cost
Land	6,100
Building and Land Improvements	10,450
Costs Capitalized Subsequent to Acquisition	1,689
Gross Amounts Carried At Close of Period
Land	6,100
Building and Land Improvements	12,139
Total	18,239
Accumulated Depreciation	(6,887)
Columbia Gateway - Southridge
Initial Cost
Land	6,387
Building and Land Improvements	3,722
Gross Amounts Carried At Close of Period
Land	6,387
Building and Land Improvements	3,722
Total	10,109
Dahlgren Technology Center
Initial Cost
Land	978
Building and Land Improvements	178
Gross Amounts Carried At Close of Period
Land	978
Building and Land Improvements	178
Total	1,156
Expedition VII
Initial Cost
Land	705
Building and Land Improvements	7,208
Gross Amounts Carried At Close of Period
Land	705
Building and Land Improvements	7,208
Total	7,913
IN 1
Initial Cost
Land	1,815
Building and Land Improvements	16,017
Gross Amounts Carried At Close of Period
Land	1,815
Building and Land Improvements	16,017
Total	17,832
Accumulated Depreciation	(1,136)
IN 2
Initial Cost
Land	2,627
Building and Land Improvements	28,936
Gross Amounts Carried At Close of Period
Land	2,627
Building and Land Improvements	28,936
Total	31,563
Accumulated Depreciation	(1,804)
M Square Research Park
Initial Cost
Building and Land Improvements	2,417
Gross Amounts Carried At Close of Period
Building and Land Improvements	2,417
Total	2,417
MR Land
Initial Cost
Land	9,038
Building and Land Improvements	554
Gross Amounts Carried At Close of Period
Land	9,038
Building and Land Improvements	554
Total	9,592
National Business Park North
Initial Cost
Land	18,232
Building and Land Improvements	36,875
Gross Amounts Carried At Close of Period
Land	18,232
Building and Land Improvements	36,875
Total	55,107
North Gate Business Park
Initial Cost
Land	1,755
Building and Land Improvements	5
Gross Amounts Carried At Close of Period
Land	1,755
Building and Land Improvements	5
Total	1,760
NoVA Office A
Initial Cost
Land	2,096
Building and Land Improvements	46,849
Gross Amounts Carried At Close of Period
Land	2,096
Building and Land Improvements	46,849
Total	48,945
Accumulated Depreciation	(8,096)
NoVA Office B
Initial Cost
Land	739
Building and Land Improvements	38,376
Gross Amounts Carried At Close of Period
Land	739
Building and Land Improvements	38,376
Total	39,115
Accumulated Depreciation	(4,715)
NoVA Office C
Initial Cost
Land	7,751
Building and Land Improvements	78,907
Gross Amounts Carried At Close of Period
Land	7,751
Building and Land Improvements	78,907
Total	86,658
Accumulated Depreciation	(477)
NoVA Office D
Initial Cost
Land	6,587
Building and Land Improvements	40,559
Gross Amounts Carried At Close of Period
Land	6,587
Building and Land Improvements	40,559
Total	47,146
Accumulated Depreciation	(4,466)
Oak Grove A
Initial Cost
Land	12,866
Building and Land Improvements	34,814
Gross Amounts Carried At Close of Period
Land	12,866
Building and Land Improvements	34,814
Total	47,680
Accumulated Depreciation	(1,358)
Oak Grove B
Initial Cost
Land	12,866
Building and Land Improvements	41,083
Gross Amounts Carried At Close of Period
Land	12,866
Building and Land Improvements	41,083
Total	53,949
Accumulated Depreciation	(1,832)
Oak Grove C
Initial Cost
Land	9,491
Building and Land Improvements	64,671
Gross Amounts Carried At Close of Period
Land	9,491
Building and Land Improvements	64,671
Total	74,162
Accumulated Depreciation	0
Oak Grove Phase II
Initial Cost
Land	13,992
Building and Land Improvements	13,820
Gross Amounts Carried At Close of Period
Land	13,992
Building and Land Improvements	13,820
Total	27,812
Old Annapolis Road
Initial Cost
Land	1,637
Building and Land Improvements	5,500
Costs Capitalized Subsequent to Acquisition	6,755
Gross Amounts Carried At Close of Period
Land	1,637
Building and Land Improvements	12,255
Total	13,892
Accumulated Depreciation	(5,362)
P2 A
Initial Cost
Land	16,853
Building and Land Improvements	40,132
Gross Amounts Carried At Close of Period
Land	16,853
Building and Land Improvements	40,132
Total	56,985
Accumulated Depreciation	(1,739)
P2 B
Initial Cost
Land	22,839
Building and Land Improvements	36,362
Gross Amounts Carried At Close of Period
Land	22,839
Building and Land Improvements	36,362
Total	59,201
Accumulated Depreciation	(1,194)
P2 C
Initial Cost
Land	14,869
Building and Land Improvements	31,482
Gross Amounts Carried At Close of Period
Land	14,869
Building and Land Improvements	31,482
Total	46,351
Accumulated Depreciation	(828)
Patriot Ridge
Initial Cost
Land	18,517
Building and Land Improvements	14,573
Gross Amounts Carried At Close of Period
Land	18,517
Building and Land Improvements	14,573
Total	33,090
Project EL
Initial Cost
Land	7,430
Building and Land Improvements	45,226
Gross Amounts Carried At Close of Period
Land	7,430
Building and Land Improvements	45,226
Total	52,656
Accumulated Depreciation	(552)
Project EX
Initial Cost
Land	13,010
Building and Land Improvements	19,097
Gross Amounts Carried At Close of Period
Land	13,010
Building and Land Improvements	19,097
Total	32,107
Accumulated Depreciation	(1,174)
PS A
Initial Cost
Land	4,078
Building and Land Improvements	2,200
Gross Amounts Carried At Close of Period
Land	4,078
Building and Land Improvements	2,200
Total	6,278
PS B
Initial Cost
Land	3,468
Building and Land Improvements	1,940
Gross Amounts Carried At Close of Period
Land	3,468
Building and Land Improvements	1,940
Total	5,408
Redstone Gateway
Initial Cost
Building and Land Improvements	29,937
Gross Amounts Carried At Close of Period
Building and Land Improvements	29,937
Total	29,937
Sentry Gateway - T
Initial Cost
Land	14,020
Building and Land Improvements	38,804
Costs Capitalized Subsequent to Acquisition	13
Gross Amounts Carried At Close of Period
Land	14,020
Building and Land Improvements	38,817
Total	52,837
Accumulated Depreciation	(14,443)
Sentry Gateway - V
Initial Cost
Building and Land Improvements	1,066
Gross Amounts Carried At Close of Period
Building and Land Improvements	1,066
Total	1,066
Accumulated Depreciation	(348)
Sentry Gateway - W
Initial Cost
Building and Land Improvements	1,884
Costs Capitalized Subsequent to Acquisition	71
Gross Amounts Carried At Close of Period
Building and Land Improvements	1,955
Total	1,955
Accumulated Depreciation	(599)
Sentry Gateway - X
Initial Cost
Land	1,964
Building and Land Improvements	21,178
Gross Amounts Carried At Close of Period
Land	1,964
Building and Land Improvements	21,178
Total	23,142
Accumulated Depreciation	(5,905)
Sentry Gateway - Y
Initial Cost
Land	1,964
Building and Land Improvements	21,298
Gross Amounts Carried At Close of Period
Land	1,964
Building and Land Improvements	21,298
Total	23,262
Accumulated Depreciation	(5,940)
Sentry Gateway - Z
Initial Cost
Land	1,964
Building and Land Improvements	30,573
Gross Amounts Carried At Close of Period
Land	1,964
Building and Land Improvements	30,573
Total	32,537
Accumulated Depreciation	(5,203)
SP Manassas
Initial Cost
Land	8,156
Building and Land Improvements	300
Gross Amounts Carried At Close of Period
Land	8,156
Building and Land Improvements	300
Total	8,456
Westfields - Park Center
Initial Cost
Land	8,667
Building and Land Improvements	3,155
Gross Amounts Carried At Close of Period
Land	8,667
Building and Land Improvements	3,155
Total	11,822
Other Developments, including intercompany eliminations
Initial Cost
Building and Land Improvements	506
Costs Capitalized Subsequent to Acquisition	259
Gross Amounts Carried At Close of Period
Building and Land Improvements	765
Total	765
Accumulated Depreciation	$ (115)

Schedule III - Real Estate an_3

Schedule III - Real Estate and Accumulated Depreciation (Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Changes in cost of properties
Beginning balance	$ 4,686,802	$ 4,348,006	$ 4,148,529
Improvements and other additions	342,684	405,940	480,418
Sales	(103,097)	(65,475)	(242,497)
Impairments	0	(1,530)	(329)
Other dispositions	(4,511)	(139)	(340)
Reclassification from (to) right-of-use asset	37,831	0	(37,775)
Ending balance	4,959,709	4,686,802	4,348,006
Changes in accumulated depreciation
Beginning balance	1,124,253	1,007,120	897,903
Depreciation expense	130,604	119,377	117,973
Sales	(15,438)	(2,105)	(8,416)
Other dispositions	(4,511)	(139)	(340)
Ending balance	$ 1,234,908	$ 1,124,253	$ 1,007,120